, 


THE  LIBRARY 

OF 

THE  UNIVERSITY 
OF  CALIFORNIA 


PRESENTED  BY 

PROF.  CHARLES  A.  KOFOID  AND 
MRS.  PRUDENCE  W.  KOFOID 


PRINCIPLES 


HUMAN  PHYSIOLOGY, 


PRINCIPLES 


HUMAN   PHYSIOLOGY, 

WITH  TilEIK  CHIEF  . 

• 

APPLICATIONS  TO  PSYCHOLOGY,  PATHOLOGY,  THERAPEUTICS, 
HYGIENE,  AND  FORENSIC  MEDICINE. 

BY 

WILLIAM  B.  CARPENTER,  M.D.,F.R.S.,F.G.S., 

EXAMINER  IX  PHYSIOLOGY  AND  COMPARATIVE  ANATOMY 

IN  THE  UNIVERSITY  OF  LONDON,  PROFESSOR  OF  MEDICAL  JURISPRUDENCE 

IN  UNIVERSITY  COLLEGE,  ETC. 


JFtfif)  Enumait  from  if)*  JFourtfi  anfc  SEitl-argJtfc  3Lonirott 

WITH  THREE  HUNDRED  AND  FOURTEEN  ILLUSTRATIONS. 

EDITED,    WITH    ADDITIONS, 
BY 

FRANCIS  GURNET  SMITH,  M.D., 

PROFESSOR  OF  THE  INSTITUTES  OP  MEDICINE  IN  THE  MEDICAL  DEPARTMENT  OF  PENNSYLVANIA  COLLEGE, 
LECTURER  ON  PHYSIOLOGY  IN  THE  PHILADELPHIA  ASSOCIATION  FOR  MEDICAL  INSTRUCTION,  ETC. 


PHILADELPHIA: 

BLANCHARD    AND    LEA. 

1853. 


Entered  according  to  the  Act  of  Congress,  in  the  year  1852,  by 
BLANCHARD  AND  LEA, 

in  the  Office  of  the  Clerk  of  the  District  Court  of  the  United  States  in  and  for  the 
Eastern  District  of  Pennsylvania. 


PHILADELPHIA  : 
T.  K.  AND  P.  G.  COLLINS,  PRINTERS. 


k.  \bm-w 


TO 

WILLIAM   PULTENEY  ALISON, 

M.D.,  F.R.S.E.  Ac.  &c. 

PROFESSOR  OP  THE  PRACTICE   OF  MEDICINE   OF  THE   UNIVERSITY  OF  EDINBURGH. 


MY  DEAR  SIR, 

I  take  the  liberty  of  inscribing  the  following  Work  to  you,  as  an 
expression  of  my  grateful  remembrance  of  the  value  of  your  instruc- 
tions, of  my  respect  for  those  Intellectual  faculties  which  render  you 
pre-eminent  amongst  the  Medical  Philosophers  of  our  time,  and  of  my 
admiration  for  those  Moral  excellencies  which  call  forth  the  warm  re- 
gard of  all  who  are  acquainted  with  your  character. 

In  many  parts  of  this  Treatise,  you  will  find  that  doctrines,  which 
you  have  long  upheld  in  opposition  to  almost  the  whole  Physiological 
world,  are  defended  with  such  resources  as  I  could  command ;  and  that, 
in  many  instances,  such  convincing  evidence  of  their  truth  has  been 
afforded  by  recent  observations,  that  further  opposition  to  them  would 
now  seem  vain.  And  if  I  have  presumed  to  differ  from  you  on  some 
points,  it  has  been  in  the  spirit  of  that  independence,  which  you  have 
uniformly  encouraged  in  your  pupils ;  yet  with  a  distrust  of  my  own 
judgment,  wherever  it  came  into  collision  with  yours. 

That  you  may  long  be  spared  to  be  the  ornament  of  your  University, 
and  the  honor  of  your  City,  is  the  earnest  wish  of, 

Dear  Sir, 

Your  obliged  Pupil, 

WILLIAM  B.  CARPENTER. 


EDITOR'S    NOTICE. 


A  GLANCE  at  the  Author's  Preface  will  show  that  the  present  edition 
has  been  remodelled  to  an  extent  which  renders  it  almost  a  new  work. 
Dr.  Carpenter's  untiring  industry  has  left  little  for  the  American  editor 
to  add  beyond  an  occasional  illustration  of  the  text,  or  notice  of  more 
recent  discoveries.  Upwards  of  one  hundred  wood-engravings  have 
been  introduced  through  the  liberality  of  the  publishers  (the  greater 
number  by  the  Author  in  his  preparation  of  the  sheets  for  this  Ameri- 
can edition),  by  which,  it  is  hoped,  its  value  is  greatly  enhanced.  It 
is  confidently  believed  that  the  present  will  more  than  sustain  the 
enviable  reputation  already  attained  by  former  editions,  of  being  one 
of  the  fullest  and  most  complete  treatises  on  the  subject  in  the  English 
language.  + 

The  additional  matter  is  inclosed  in  brackets  [  ]. 

291  SPRUCE  STREET,  Nov.  1852. 


AUTHOR'S    PREFACE 


FIFTH  AMERICAN  AND  FOURTH  ENGLISH  EDITION. 


THE  Author  feels  it  necessary  to  apologize  to  those,  whose  kind  ap- 
preciation of  the  following  work  occasioned  a  call  for  a  New  Edition 
as  much  as  two  years  since,  for  the  delay  which  has  attended  its  ap- 
pearance. Having  been  at  that  time  engaged  in  rewriting  his  "  Prin- 
ciples of  General  and  Comparative  Physiology,"  he  felt  that  he  could 
not  do  justice  to  that  work,  if  he  were  not  to  bring  it  to  a  conclusion 
before  taking  another  in  hand ;  and  when,  on  the  completion  of  that 
task,  he  applied  himself  to  the  preparation  of  his  "  Principles  of 
Human  Physiology,"  for  the  press,  he  found  that  nothing  short  of  an 
entire  remodelling  of  the  preceding  Edition  would  in  any  degree  satisfy 
his  notions  of  what  such  a  treatise  ought  to  be.  For  although  no  fun- 
damental change  had  taken  place  during  the  interval  in  the  fabric  of 
Physiological  Science,  yet  a  large  number  of  less  important  modifica- 
tions had  been  effected,  which  had  combined  to  produce  a  very  con- 
siderable alteration  in  its  aspect.  Moreover,  the  progressive  maturation 
of  his  own  views,  and  his  increased  experience  as  a  Teacher,  had  not 
only  rendered  him  more  keenly  alive  to  the  imperfections  which  were 
inherent  in  its  original  plan,  but  had  caused  him  to  look  upon  many 
topics  in  a  light  very  different  from  that  under  which  he  had  previously 
regarded  them ;  and,  in  particular,  he  felt  a  strong  desire  to  give  to  his 
work  as  practical  a  character  as  possible,  without  foregoing  the  position 
which  (he  trusts  he  may  say  without  presumption)  he  had  succeeded  in 
gaining  for  it,  as  a  philosophical  exposition  of  one  important  department 
of  Physiological  Science.  He  was  led,  therefore,  to  the  determination 
of,  in  reality,  producing  a  new  treatise,  in  which  only  those  parts  of  the 
old  should  be  retained,  which  might  express  the  existing  state  of  know- 
ledge, and  of  his  own  opinions,  on  the  points  to  which  they  relate ;  and 


X  PREFACE   TO   THE   FOURTH   EDITION. 

the  following  outline  of  the  changes  which  he  has  made  will  show  the 
extent  to  which  this  reconstruction  has  been  accomplished : — 

Considering  it  extremely  important  that  his  readers  should  have  a 
clear  idea  of  the  sense  in  which  the  terms  Law  and  Cause  are  subse- 
quently employed,  he  has  devoted  a  few  pages  of  the  Introduction  to 
an  explanation  of  his  views  upon  these  points ;  and  he  hopes  that  he 
may  be  there  found  to  have  thrown  some  light  upon  the  philosophy  of 
causation,  which  may  be  of  assistance  to  other  scientific  inquirers. 

In  order  to  make  room  for  a  portion  of  the  new  matter  which  he 
desired  to  introduce  into  the  treatise,  he  has  felt  it  necessary  to  omit  all 
those  references  to  the  structure  and  vital  actions  of  the  lower  animals 
which  had  not  an  immediate  and  direct  bearing  upon  Human  Physiology ; 
and  consequently,  of  the  First  Chapter  of  the  previous  editions — "  On 
the  Place  of  Man  in  the  Scale  of  Being," — he  has  only  retained  so 
much  as  related  to  the  characteristics  that  distinguish  Man  from  the 
Mammalia  which  most  nearly  approach  him.  The  succeeding  Chapter, 
which  treated  "  Of  the  Different  Branches  of  the  Human  Family  and 
their  Mutual  Relations,"  has  been  extended  in  all  that  relates  to  Man, 
and  curtailed  in  that  which  rather  belongs  to  Comparative  Physiology ; 
and  has  been  transferred  to  nearly  the  end  of  the  volume,  which  the 
Author  considers  to  be  now  the  more  appropriate  place  for  it. 

The  Second  Chapter  of  the  present  Edition,  comprising  a  general 
view  "Of  the  Chemical  Components  of  the  Human  Body,  and  the 
Changes  which  they  undergo  within  it,"  is  now  for  the  first  time  intro- 
duced. The  Author  has  aimed  to  render  it  as  complete  as  its  necessary 
limits  would  permit;  and  hopes  that  he  will  be  found  not  to  have  omitted 
anything  truly  important,  and  to  have  presented  a  faithful,  though  con- 
cise exposition  of  the  present  state  of  our  knowledge  upon  this  import- 
ant subject.  In  the  preparation  of  this  Chapter,  he  has  made  great 
use  of  the  admirable  "Physiological  Chemistry"  of  Prof.  Lehmann, 
now  in  progress  of  translation  by  Prof.  Day  for  the  Cavendish  Society; 
and  not  only  this,  but  other  portions  of  his  work  that  involve  a  scientific 
knowledge  of  Organic  Chemistry,  have  had  the  advantage  of  Prof. 
Day's  revision — a  service  for  which  the  Author  feels  greatly  indebted, 
both  for  himself,  and  in  behalf  of  his  readers.  Several  new  views  will 
be  found  in  this  Chapter,  which  have  occurred  to  the  Author  during  its 
preparation  ;  he  would  especially  point  to  that  of  the  respective  rela- 
tions of  Fibrin  and  Albumen  to  the  nutritive  processes,  and  of  the  for- 
mer to  the  Gelatinous  tissues  (§§  29,  30) ;  and  to  the  General  Summary 
which  forms  the  last  section,  in  which  the  discoveries  of  M.  Cl.  Bernard 
in  regard  to  the  elaboration  of  sugar  and  fat  in  the  Liver,  are  placed 
(he  believes)  in  a  somewhat  novel  aspect. 


PREFACE   TO    THE   FOURTH   EDITION.  XI 

From  the  consideration  of  .the  chemical  components  of  the  organism, 
and  of  the  participation  of  chemical  forces  in  its  operations,  it  seemed 
natural  to  pass  on  to  that  of  "  The  Structural  Elements  of  the  Human 
Body,  and  the  Vital  Actions  which  they  exhibit,"  which  forms  the  sub- 
ject of  the  Third  Chapter.  Nearly  the  whole  of  this  Chapter,  which 
includes  the  general  doctrines  of  Cell-formation  and  of  Vital  Force,  in 
their  application  to  Human  Physiology,  appears  for  the  first  time  in 
this  edition. 

Passing  on  to  the  more  detailed  survey  of  the  constituent  parts  of  the 
Human  body,  the  first  place  seemed  to  be  claimed  by  the  Blood;  the 
"Physical  Characters,  Chemical  Composition,  and  Vital  Properties"  of 
which  are  treated  of  at  some  length  in  Chapter  IV.  This  portion  has 
been  greatly  extended,  and  almost  entirely  rewritten ;  the  great  import- 
ance of  the  subject,  in  its  bearings  on  Pathology  as  well  as  on  Physio- 
logy, having  been  constantly  kept  in  view.  The  Author  does  not  profess 
to  have  included  by  any  means  all  that  might  have  been  brought  together 
on  the  subject ;  but  he  has  selected  those  facts  with  which  he  considered 
it  most  important  that  his  readers  should  be  acquainted,  and  those  doc- 
trines which  seemed  to  him  to  have  the  most  direct  practical  applications. 
As  original  contributions  to  this  department  of  Physiology,  he  would 
especially  point  to  the  correction  (§  154)  of  the  ordinary  analyses  of  the 
Blood  (the  essential  point  of  which,  he  may  remark,  has  been  brought 
under  the  notice  of  the  French  Academy  by  M.  Lecanu,  some  months 
since  this  chapter  passed  through  the  press);  and  to  the  account  of  that 
state  of  the  blood  which  gives  a  special  predisposition  to  zymotic  dis- 
ease (§  210) — a  doctrine,  which,  although  to  a  certain  extent  hypothe- 
tical, will  be  found  (he  believes)  to  be  in  such  strict  accordance  with  all 
the  known  facts  bearing  upon  the  subject,  as  to  be  almost  entitled  to 
rank  as  a  legitimate  generalization  of  them. 

The  Fifth  Chapter,  "  On  the  Primary  Tissues  of  the  Living  Body; 
their  Structure,  Composition,  and  Actions,"  is  essentially  the  same  with 
the  Third  Chapter  of  the  previous  Edition ;  but  a  large  amount  of  new 
matter,  in  great  part  supplied  by  the  elaborate  "  Mikroscopische  Ana- 
tomie"  of  Prof.  Kblliker,  has  been  incorporated  in  it;  and  many  new 
illustrations,  chiefly  derived  from  the  same  source,  have  been  introduced. 
The  account  of  the  vital  endowments  of  the  Muscular  and  Nervous  tis- 
sues, previously  contained  in  other  chapters,  has  been  transferred  to 
this ;  so  as  to  make  it  embody  a  complete  sketch  of  those  physiological 
actions  of  the  separate  parts  of  the  organism,  which  are  afterwards  to 
be  considered  in  their  relations  to  each  other. 

This  Chapter  is  followed,  as  in  the  previous  Edition,  by  a  "  General 


Xll  PREFACE   TO   THE   FOURTH   EDITION. 

View  of  the  Functions  of  the  Human  Body"  (CHAP,  vi.),  in  which  there 
has  been  but  little  alteration. 

In  conformity  with  the  opinion  expressed  by  some  of  his  friendly 
Critics,  and  by  many  Teachers  of  Physiology,  the  Author  has  reversed 
the  previous  arrangement  of  the  Chapters  which  treat  of  the  Functions 
in  detail ;  those  relating  to  the  Organic  Functions  being  now  placed 
before  those  in  which  the  Animal  Functions  are  described,  instead  of 
after.  This  has  involved  a  new  distribution  of  much  of  the  matter 
which  was  previously  treated  in  a  connected  form  in  the  Chapter  on 
the  "  Functions  of  the  Nervous  System;"  since  it  has  appeared  to  the 
Author  very  desirable  that  the  whole  group  of  actions  whose  aggregate 
makes  up  each  function,  should  now  be  considered  in  its  connection;  and 
thus  the  movements  of  Deglutition,  Eespiration,  &c.,  not  having  been 
explained  (as  was  formerly  the  case)  in  the  earlier  part  of  the  volume, 
are  described,  and  their  connection  with  the  Nervous  System  examined, 
under  each  separate  head.  As  their  general  relations  to  the  Nervous 
System  are  previously  explained,  however,  in  the  Sixth  Chapter,  the 
Author  does  not  apprehend  that  any  inconvenience  will  be  experienced 
from  this  alteration. — By  the  adoption  of  this  change,  in  some  degree 
against  his  own  judgment,  the  Author  trusts  that  he  has  sufficiently 
marked  his  desire  to  profit  by  all  such  advice  as  may  be  tendered  to 
him  in  a  friendly  spirit,  and  by  those  whose  position  or  attainments 
give  value  to  their  opinion. 

The  series  of  Chapters  on  the  several  Organic  Functions  remain 
essentially  the  same  as  in  the  previous  Edition;  but  important  additions 
and  corrections  have  been  made  in  every  one.  Thus,  in  Chapter  vii. 
"On  Food  and  the  Digestive  Process,"  the  whole  subject  of  Food  is 
much  more  fully  discussed  than  heretofore ;  and  the  most  important  of 
the  results  obtained  from  the  study  of  the  Digestive  Process  by  Fre- 
richs,  Bernard,  and  other  experimenters,  have  been  embodied  in  the 
account  of  it.  In  Chapter  vin.,  "  On  Absorption  and  Sanguification," 
the  structure  and  development  of  the  Ductless  Glands  have  been  more 
fully  described,  in  accordance  with  the  researches  of  Kblliker,  Sanders, 
Ecker,  Gray,  and  others ;  and  their  relation  to  the  process  of  Sanguifi- 
cation more  clearly  elucidated.  In  Chapter  ix.  "  On  the  Circulation 
of  the  Blood,"  the  causes  of  the  Heart's  Sounds  have  been  more  fully 
considered ;  a  view  of  the  nature  of  its  rhythmical  contractions  has 
been  suggested  (§§  498,  499),  which  the  Author  believes  to  be  original ; 
and  the  most  important  among  the  results  of  Prof.  Volkmann's  elabo- 
rate researches  on  the  Dynamics  of  the  Movement  of  the  Blood  have 
been  introduced.  In  Chapter  x.,  "  On  Respiration,"  the  most  import- 
ant additions  to  the  first  section  are  those  which  embody  the  results  of 


PREFACE   TO    THE   FOURTH   EDITION.  Xlll 

Dr.  Hutchison's  inquiries  on  the  movements  of  Respiration ;  to  the 
second,  the  data  furnished  by  the  researches  of  MM.  Regnault  and 
Reiset,  Prof.  Scharling,  M.  Barral,  and  others,  upon  the  amount  of 
Oxygen  absorbed  and  of  Carbonic  Acid  exhaled ;  whilst  the  third,  in 
which  the  "Effects  of  Suspension  or  Deficiency  of  Respiration"  are 
discussed,  has  been  largely  augmented  by  a  summary  of  the  evidence 
afforded,  by  our  recent  experience,  of  the  marked  tendency  of  an  habitu- 
ally imperfect  Respiration  to  produce  a  liability  to  Zymotic  disease. 
Nearly  the  whole  of  Chapter  xi.,  ".On  Nutrition,"  has  been  newly 
written  for  this  Edition ;  and  here,  as  elsewhere,  the  Author  has  been 
greatly  indebted  to  the  Hunterian  Lectures  of  his  friend,  Mr.  Paget, 
whose  contributions  to  this  department  of  Physiology  he  regards  as  of 
the  highest  scientific  as  well  as  practical  value.  He  cannot  forbear, 
moreover,  to  express  the  pleasure  which  he  has  derived,  from  finding 
that  Mr.  -Paget  most  fully  recognizes,  and  gives  him  credit  for  two  im- 
portant doctrines  which  he  had  taught  in  former  editions  of  this  work ; 
namely,  the  limits  to  the  Duration  of  individual  parts,  imposed  by  the 
very  fact  of  their  independent  vitality,  and  varying  with  the  activity,  of 
their  vital  operations ;  and  the  diminished  formative  power  of  the  tissues, 
as  one  of  the  essential  constituents  of  the  state  of  Inflammation.  In 
Chapter  xn.,  "On  Secretion  and  Excretion,"  important  additions  have 
been  made  under  almost  every  head ;  and  those  parts,  especially,  which 
relate  to  the  agency  of  the  Excretory  apparatus  in  maintaining  the 
purity  of  the  Blood,  have  been  extended.  This  Chapter,  however,  is 
less  comprehensive  than  formerly ;  several  of  the  subjects  which  it  pre- 
viously included,  having  been  transferred  to  portions  of  the  work  in 
which  they  seemed  to  find  more  appropriate  places  ;  the  Salivary  and 
Pancreatic  secretions  being  now  treated  of  in  the  Chapter  on  Digestion, 
and  those  of  the  Testes  and  Mammae  in  that  on  Generation.  Of  the 
three  subjects  included  in  Chapter  xin.,  "  On  the  Evolution  of  Heat, 
Light,  and  Electricity,"  the  first  alone  had  been  systematically  con- 
sidered in  the  previous  editions,  and  this  has  been  considerably  ex- 
tended in  the  present ;  under  the  second  head  will  be  found  some  very 
curious  observations  on  the  evolution  of  Light  in  the  living  Human 
subject ;  and  under  the  third  is  given  a  summary  of  the  results  of  the 
admirable  researches  of  M.  Du  Bois-Reymond,  which  have  been  recently 
brought  before  the  scientific  public  in  this  country  by  Dr.  Bence  Jones. 
It  is  in  the  Chapter  (xiv.)  devoted  to  the  Functions  of  the  Nervous 
System,  which  constitutes  one-fifth  of  the  entire  volume,  that  the  great- 
est additions  and  alterations  will  be  found.  This  subject,  in  its  Psycho- 
logical as  well  as  in  its  Physiological  relations,  has  occupied  more  of  the 
Author's  attention  than  any  other  department  of  Physiology ;  and  he 


Xv  PREFACE   TO   THE   FOURTH  EDITION. 

now  offers  the  more  matured  fruits  of  his  inquiries  and  reflections,  with 
some  confidence  that,  even  if  his  views  should  hereafter  require  modifi- 
cation as  to  details,  they  will  be  found  to  be  fundamentally  correct,  and 
to  furnish  materials  of  some  value  in  Psychological  inquiry,  as  well  as 
in  the  study  of  Mental  Pathology, — a  subject  which  is  now  receiving  for 
the  first  time  (in  this  country,  at  least)  the  attention  which  its  vast  im- 
portance demands.  The  peculiar  states  which  are  known  under  the 
designations  of  Somnambulism,  Hypnotism,  Mesmerism,  Electro-Biology, 
&c.,  are  all  considered  in  their  relations,  to  Sleep  on  the  one  hand,  and 
to  the  ordinary  condition  of  Mental  Activity  on  the  other  ;  and  the 
Author  ventures  to  believe  that  he  has  not  only  succeeded  in  throwing 
considerable  light  upon  the  nature  of  these  aberrant  forms  of  psychical 
action,  but  that  he  has  been  enabled  to  deduce  from  their  phenomena 
some  inferences  of  great  importance  in  Psychological  science.  He 
would  particularly  refer  to  all  that  portion  of  Section  5  ("  On  the  Cere- 
brum and  its  Functions")  which  relates  to  the  Automatic  operations  of 
the  Mind,  and  to  the  relation  of  the  Will  to  these,  as  opening  up  what 
he  believes  to  be  an  entirely  new  line  of  inquiry. 

It  is  with  great  satisfaction  that  he  can  refer  to  his  friends,  Dr.  Hol- 
land and  Dr.  Laycock,  as  participating  (in  regard  to  all  essential  points 
at  least)  in  his  own  views  on  all  these  subjects ;  and  though  all  which 
he  has  here  written  upon  them  is  the  expression  of  the  results  of  his 
own  observation  and  reflection,  yet  he  gladly  takes  this  opportunity  of 
acknowledging  the  great  benefit  which  he  has  derived  from  the  writings 
and  conversation  of  these  philosophical  and  independent  thinkers.  It 
would  be  ungrateful  if  he  were  not  also  to  record  his  obligations  to  his 
friendj,  Mr.  John  S.  Mill,  and  Mr.  Daniel  Morell,  who  have  allowed  him 
to  bring  his  Psychological  views  under  their  notice,  from  time  to  time, 
and  to  subject  them  to  the  test  of  their  own  far  more  extensive  and 
profound  acquaintance  with  that  department  of  his  inquiry. 

In  Chapter  XV.,  "  On  Sensation,  and  the  Organs  of  the  Senses," 
comparatively  little  change  has  been  made;  several  additions  have  been 
introduced,  however,  and  some  corrections  made.  The  next  Chapter 
(xvi.),  "  On  Muscular  Movements,"  has  been  entirely  remodelled,  the 
portion  which  relates  to  the  vital  endowments  of  Muscular  Fibre  having 
been  removed  to  Chapter  V.,  Section  6,  and  its  place  supplied  by  new 
matter  which  contains  many  original  views,  especially  under  Section  4, 
which  treats  of  "the  Influence  of  Expectant  Attention  on  Muscular 
Movements."  Comparatively  little  alteration  has  been  found  necessary 
in  Chapter  xvil.,  "  On  the  Voice  and  Speech,"  or  in  Chapter  xvili., 
"  On  the  Influence  of  the  Nervous  System  on  the  Organic  Functions ;" 
an  important  addition  has  been  made  to  the  latter,  however,  with  refer- 


PREFACE  TO  THE  FOURTH  EDITION.  XV 

ence  to  the  influence  of  the  state  of  "expectant  attention"  on  the  ope- 
rations of  Nutrition,  Secretion,  &c. 

The  additions  and  alterations  which  have  been  made  in  Chapter  xix. 
"  On  Generation,"  will  be  found  to  be  both  numerous  and  important, 
especially  under  the  Section  on  the  "Development  of  the  Embryo;" 
which  has  been  almost  entirely  rewritten,  so  .as  to  bring  the  view  of 
this  process  more  into  accordance  with  the  existing  state  of  our  know- 
ledge of  it.  The  Author  has  not  felt  it  expedient,  however  (for  the 
reasons  mentioned  in  §  922),  to  enter  into  minute  details  upon  this  sub- 
ject.. 

In  Chapter  xx.,  "  On  the  Different  Branches  of  the  Human  Family, 
and  their  Mutual  Relations,"  all  that  directly  relates  to  its  subject  has 
been  considerably  extended,  and  many  novelties  have  been  introduced ; 
whilst  those  arguments  for  the  Specific  Unity  of  the  Human  Races, 
which  are  derived  from  the  analogy  of  the  lower  animals,  have  been 
simply  referred  to, — having  been  fully  dwelt  on  by  the  Author  else- 
where. 

The  closing  Chapter,  "  On  Death,"  has  been  almost  entirely  written 
for  this  Edition ;  the  subject  having  been  only  touched  on  incidentally 
in  the  preceding. 

The  Author  trusts  that  it  will  be  apparent,  from  the  foregoing  sum- 
mary, that  he  has  spared  no  pains  to  render  the  present  Edition  worthy 
of  the  favorable  reception  which  has  been  accorded  to  its  predecessors. 
The  principle  he  has  adopted  throughout,  has  been  that  of  making  the 
Treatise  express  his  present  convictions  and  opinions,  as  completely  as 
if  it  had  now  been  for  the  first  time  put  forth ;  the  old  materials  having 
been  incorporated  with  the  new,  rather  than  the  new  with  the  old ;  and 
having  only  been  employed,  where  they  could  be  readily  made  subser- 
vient to  this  purpose.  In  making  his  selection  from  the  vast  mass  of 
results  which  have  been  recently  accumulated  by  the  diligent  labors  of 
Physiologists  of  various  countries,  the  Author  has  been  guided  by  the 
principle  which  he  expressed  in  the  preface  to  his  previous  Edition ; — 
that,  namely,  of  not  rashly  introducing  changes  inconsistent  with  usually 
received  views ; — nor,  on  the  other  hand,  showing  an  unwillingness  to 
reject  the  statements  of  those  who  have  taken  adequate  pains  to  arrive 
at  accurate  conclusions.  "  He  trusts  that  he  may  be  found" — now  as 
then — "  to  have  exercised  a  sound  discretion,  both  as  to  what  he  has 
admitted,  and  what  he  has  rejected ;  and  that  his  work  will  appear  to 
exhibit,  on  the  whole,  a  faithful  reflection  of  the  present  aspect  of  Phy- 
siological Science.  He  cannot  venture  to  expect,  however,  that  he  has 
succeeded  in  every  instance,  so  that  each  of  his  readers  will  be  in  con- 


XVI  PREFACE   TO   THE    FOURTH   EDITION. 

stant  agreement  with  him ;  since  it  is  impossible  that  they  should  all 
survey  the  subject  from  the  same  point  of  view." 

In  conformity  with  a  desire  frequently  expressed,  both  by  critics  and 
readers,  a  large  number  of  references  have  been  introduced;  and  to 
this  addition,  no  small  portion  of  the  augmented  bulk  of  the  volume  is 
due.  Here,  as  in  his  companion-work,  the  Author  has  felt  himself  com- 
pelled, by  want  of  space,  "  to  limit  his  references,  for  the  most  part,  to 
those  new  facts  and  doctrines,  which  cannot  yet  be  said  to  have  become 
part  of  the  common  stock  of  Physiological  Science."  The  special  In- 
dex of  "  Authors  referred  to,"  will  be  found,  he  hopes,  of  service  to 
those  who  wish  to  know  the  views  of  the  original  writers  quoted,  upon 
any  particular  topic.  To  the  knowledge  of  many  of  these,  he  has  been 
led  by  the  excellent  "  Handbook  of  Physiology"  of  Messrs  Kirkes  and 
Paget,  to  which  he  gladly  expresses  his  obligations  in  this  particular. 
He  has  himself  consulted  the  originals,  however,  in  all  cases  in  which 
he  could  gain  access  to  them. 

In  conclusion,  the  Author  would  repeat  the  remarks  with  which  he 
brought  to  a  close  the  Preface  to  the  first  Edition  (1842); — uthat  in  a 
work  involving  many  details,  it  is  not  to  be  expected  that  no  error 
should  have  crept  in ;  but  that  he  has  endeavored  to  secure  correctness, 
by  relying  only  upon  such  authorities  as  appeared  to  him  competent, 
and  by  comparing  their  statements  with  such  general  principles  as  he 
considers  well  established.  For  the  truth  of  those  principles,  he  holds 
'himself  responsible ;  for  the  correctness  of  the  details,  he  must  appeal 
to  those  from  whom  they  are  derived,  and  to  whom  he  has  generally  re- 
ferred. He  hopes  that  he  will  not  be  found  unwilling  to  modify  either, 
when  they  have  been  proved  to  be  erroneous ;  nor  indisposed  to  profit 
by  criticism,  when  administered  in  a  friendly  spirit." 

UNIVERSITY  HALL,  November,  1852. 


TABLE   OF  CONTENTS. 


INTRODUCTION. 

PAGE 

NATURE  AND  OBJECTS  OF  PHYSIOLOGICAL  SCIENCE  .          . .   ,  .          33 

CHAPTER   I. 

OF  THE  DISTINCTIVE  CHARACTERISTICS  OF  MAN      .....          41 

CHAPTER   II. 

OF  THE  CHEMICAL  COMPONENTS  OF  THE  HUMAN  BODY,  AND  THE  CHANGES  WHICH 

THEY  UNDERGO  WITHIN  IT             »  •        '  .            .             .             .             .             .  51 

1.  Albuminous  Compounds                   .  '          .             .             .             .             .  53 

2.  Gelatinous  Compounds         .......  66 

3.  Oleaginous  Compounds      .-.            .            .•           .            .            .            .  69 

4.  Saccharine  Compounds    -   .-         :•            .            .            .            .             .  75 

5.  Excrementitious  Substances       ,,  .            «            .            .            .            .  80 

6.  Inorganic  Substances  forming  part  of  the  Living  Body,  and  contained  in 

its  Excretions      .  .  .         •  ?  '.  ,  .  .98 

7.  General  Summary. — Operation  of  Chemical  Forces  in  the  Living  Body     .         112 

CHAPTER   III. 

OF  THE  STRUCTURAL  ELEMENTS  OF  THE  HUMAN  BODY,  AND  THE  VITAL  ACTIONS 

WHICH  THEY  EXHIBIT        .  .  .  .        *)..  .  .  .         119 

1.  Of  the  Elementary  Forms  of  Organic  Structure,  and  their  modes  of  Vital 

Activity  .  .  .  .  .  .  .  .120 

2.  Of  Vital  Force,  and  the  Conditions  of  its  Exercise  .  .  .140 

3.  General  Survey  of  the  Life  of  Man  .  V  .  .  .148 

CHAPTER   IV. 

OF  THE  BLOOD  ;  ITS  PHYSICAL  CHARACTERS,  CHEMICAL  COMPOSITION,  AND  VITAL 

PROPERTIES         .  .  •          .  .  .  .  .  .  .  153 

1.  General  Considerations        .  * .  c          .  .  .  .  .  153 

2.  Physical,  Chemical,  and  Structural  Characters  of  the  Blood          y^        .  156 

3.  Of  the  Vital  Properties  of  the  Blood,  and  its  Relations  to  the  Living  Organism  191 
2 


XV111  CONTENTS. 


CHAPTEK   V. 

PAGK 

OF  THE  PRIMARY  TISSUES  OF  THE  HUMAN  BODY;  THEIR  STRUCTURE,  COMPOSITION, 

AND  ACTIONS        .........  222 

1.  Of  the  Simple  Fibrous  Tissues        ......  224 

2.  Of  the  Fibro-Cellular  Membranes  and  their  Appendages                .             .  229 

3.  Of  the  purely  Cellular  Tissues;  Fat  and  Cartilage  .  .  .256 

4.  Of  the  Tissues  consolidated  by  Earthy  deposit ;  Bones  and  Teeth              .  266 

5.  Of  the  Simple  Tubular  Tissues;  Capillary  Bloodvessels  and  Absorbents    .  298 

6.  Of  the  Muscular  Tissue      .......  303 

7.  Of  the  Nervous  Tissue       .            .                        .            .            .           !  334 

CHAPTER   VI. 

GENERAL  VIEW  OF  THE  FUNCTIONS  OF  THE  HUMAN  BODY    ....        358 

1.  Of  the  Mutual  Dependence  of  its  Vital  Actions     .  .  .  .358 

2.  Functions  of  Vegetative  Life          ......        363 

3.  Functions  of  Animal  Life   .  371 


CHAPTER   VII. 

OF  FOOD  AND  THE  DIGESTIVE  PROCESS        ......  375 

1.  Of  Food,  its  Nature  and  Destination           .            ,            .            .            .  375 

2.  Of  Hunger  and  Thirst ;  Starvation            ',"'.','„          .             .             .  391 

3.  Movements  of  the  Alimentary  Canal          .            .            .            .            .  397 

4.  Of  the  Changes  which  the  Food  undergoes  during  its  passage  along  the 

Alimentary  Canal  .  .  .  .  .  .  .411 


CHAPTER   VIII. 

OF  ABSORPTION  AND  SANGUIFICATION          ......  438 

1.  Of  Absorption  from  the  Digestive  Cavity  .             .             .             .             .  438 

2.  Absorption  from  the  Body  in  General         .             .             .             .  445 

3.  Of  the  Elaboration  of  the  Nutrient  Materials.     Sanguification      .            .  449 

CHAPTER   IX. 

OF  THE  CIRCULATION  OF  THE  BLOOD           .            .            .            .            ...  466 

1.  Of  the  Circulation  in  General         .            .             .          jt            .            .  466 

2.  Action  of  the  Heart            .......  468 

3.  Movement  of  the  Blood  in  the  Arteries      .             .            .  "          .             .  482 

4.  Movement  of  the  Blood  in  the  Capillaries              ....  491 

5.  Movement  of  the  Blood  in  the  Veins          .             .             .             .            .  497 

6.  Peculiarities  of  the  Circulation  in  different  parts  ....  500 

CHAPTER   X. 

OF  RESPIRATION      .            .            .            .            .            .            .            ...  502 

1.  Nature  of  the  Function,  and  Provisions  for  its  Performance          .            .  502 


CONTENTS.  XIX 

PAGE 

2.  Effects  of  .Respiration  on  the  Air    ......        521 

3.  Effects  of  Suspension  or  Deficiency  of  Respiration  .  .  .        535 


CHAPTER   XI. 

OF  NUTRITION         .  .  .  .  .  .  .  .  .  546 

1.  General  Considerations.     Formative  Power  of  Individual  Parts    .  .  546 

2.  Varying  Activity  of  the  Nutritive  Processes.     Reparative  Operations       .  554 

3.  Abnormal  Forms  of  the  Nutritive  Process  ....  566 


CHAPTER   XII. 

OF  SECRETION  AND  EXCRETION        ,  .  .  .  .  .  .  574 

1.  Of  Secretion  in  General      .......  574 

2.  The  Liver.     Secretion  of  Bile       '».       V          .  .  .  .  581 

3.  The  Kidneys.     Secretion  of  Urine  .....  594 

4.  The  Skin.     Cutaneous  Transpiration          .          V  *  •  •  611 


CHAPTER   XIII. 

EVOLUTION  OF  HEAT,  LIOHT,  AND  ELECTRICITY       .....        614 

1.  General  Considerations       .  .  .  ~  .  .  .         614 

2.  Evolution  of  Heat .615 

3.  Evolution  of  Light          ,.'/:,  .  .  .  .  .         632 

4.  Evolution  of  Electricity      .......        633 


CHAPTER   XIV. 

OF  THE  FUNCTIONS  OF  THE  NERVOUS  SYSTEM          .....        641 

1.  General  Summary  .......         641 

2.  Of  the  Spinal  Cord  and  Medulla  Oblongata;  their  Structure  and  Actions          659 

3.  Of  the  Sensory  Ganglia  and  their  Functions.     Consensual  Movements      .         719 

4.  Of  the  Cerebellum  and  its  Functions          .  .  .  .  .728 

5.  Of  the  Cerebrum  and  its  Functions  .....        741 
Of  Sleep     ......         '  .  .  .        819 

6.  Of  the  Sympathetic  System  and  its  Functions        .  «  .  .        829 

7.  General  Recapitulation,  and  Pathological  Applications      ."  .  .831 


CHAPTER   XV. 

OF  SENSATION  AND  THE  ORGANS  OF  THE  SENSES     .....  848 

1.  Of  Sensation  in  general      .                          .             .            .             .             .  848 

2.  Sense  of  Touch       ........  858 

3.  Sense  of  Taste        ........  862 

4.  Sense  of  Smell       .           '."'"        ......  871 

5.  Sense  of  Vision      .            .            .            .            .            .            .            .  873 

6.  Sense  of  Hearing    .  ^  .  .  .  .  .894 


XX  CONTENTS. 


CHAPTEK   XVI. 

PAGE 

OF  MUSCULAB  MOVEMENTS  .......        909 

1.  General  Considerations        .......         909 

2.  Of  the  Symmetry  and  Harmony  of  Muscular  Movements    •  .  .911 

3.  Energy  and  Rapidity  of  Muscfftar  Contraction       .  .  .  .917 

4.  On  the  Influence  of  Expectant  Attention  on  Muscular  Movements  .        920 


CHAPTER  XVII. 

OF  THE  VOICE  AND  SPEECH             .            .  .            .  .            .            .'       924 

1.  Of  the  Larynx  and  its  Actions        .  .-         ,  .     t        .            .         924 

2.  Of  Articulate  Sounds  935 


CHAPTER   XVIII. 

OF  THE  JNFLUENCE  OF  THE  NERVOUS  SYSTEM  ON  THE  ORGANIC  FUNCTIONS              .  941 

CHAPTER   XIX. 

OF  GENERATION       .         „  ,            .            .            .            .  .                         .  948 

1.  General  Character  of  the  Function  .  .   •  .  .948 

2.  Action  of  the  Male              .         '    .    •    •  •   .  • ;         .  .             .             .  951 

3.  Action  of  the  Female          .  .  .  .  •  .  .957 

4.  Development  of  the  Embryo           .             .  '         .  .             .             .  985 

5.  Of  Lactation           .            .            .            .            „  .            .            .  1018 

CHAPTER   XX. 

OF  THE  DIFFERENT  BRANCHES  OF  THE  HUMAN  FAMILY  AND  THEIR  MUTUAL  RELA- 
TIONS      .            .            .        '     .            .            .            .  .            .            .  1029 

1.  General  Considerations       .            .            .            .  .            .            .  1029 

2.  General  Survey  of  the  Principal  Families  of  Mankind  .             .             .  1042 

CHAPTER   XXI. 

OF  DEATH   .  1054 


LIST  OF  WOOD-ENGRAVINGS. 


FIG.  PAGE 

1.  View  of  the  base  of  the  Skull  of  Man,  compared  with  that  of  the  Orang- 

Outan;  after  Owen  .  .  .  .  .  .  .43 

2.  Comparative  view  of  the  Skeleton  of  Man,  and  that  of  the  Orang-Outan        .  45 
2*.-  Fibrous  structure  of  Inflammatory  Exudation ;  after  Gerber             .             .  61 

3.  Fibrous  membrane  from  the  Egg- sh elk;  original          ....  62 

4.  Cells  from  Chorda  Dorsalis  of  Lamprey ;  after  Quekett  .  .  .121 

5.  Haematococcus  Binalis,  in  various  stages  of  development ;  after  Hassall         .  125 

6.  Multiplication  of  Cells  by  binary  subdivision                ....  125 

7.  Multiplication  of  Cartilage-cells  by  duplication ;  after  Leidy               .             .  126 

8.  Section  of  branchial  Cartilage  of  Tadpole ;  after  Schwann      .             .             .  127 

9.  Endogenous  Cell-growth  in  cells  of  a  meliceritous  tumor ;  after  Goodsir         .  127 

10.  Cells  with  radiating  fibres ;  after  Addison        .....  138 

11.  Red  Corpuscles  of  Human  Blood ;  after  Donne            ....  158 

12.  Red  Corpuscles  of  Frog's  Blood ;  after  Wagner  .  .  .  .159 

13.  Capillaries  of  the  Frog's  foot  .......  164 

14.  Development  of  the  first  set  of  Red  Corpuscles  in  the  blood  of  the  Batrachian 

Larva        .........  166 

15.  Development  of  the  first  set  of  Red  Corpuscles  in  the  blood  of  the  Mamma- 

lian Embryo          ........  167 

16.  Development  of  Human  Lymph  and  Chyle-corpuscles  into  Red  Corpuscles  of 

the  Blood               ........  168 

17.  Microscopic  appearance  of  a  drop  of  Blood  in  the  Inflammatory  condition ; 

after  Addison        ........  199 

18.  White  Fibrous  Tissue,  from  Ligament ;  original           ....  224 

19.  Yellow  Fibrous  Tissue,  from  Ligamentum  nuchse ;  original     .             .             .  225 

20.  Arrangement  of  Fibres  in  Areolar  Tissue ;  original     ....  226 

21.  The  two  elements  of  Areolar  Tissue,  in  their  natural  relations  to  one  another  227 

22.  Development  of  Fibres  from  Cells ;  after  Lebert          ....  228 

23.  Diagram  of  the  structure  of  an  Involuted  Mucous  Membrane ;  after  Todd     .  233 

24.  Pavement  Epithelium- Cells ;  after  Lebert        .  .  .  .  .235 

25.  Cylinder-Epithelium ;  after  Kolliker    ......  235 

26.  Vibratile  or  Ciliated  Epithelium ;  after  Henle              ....  236 

27.  Villi  of  the  Human  Intestine ;  after  Kolliker  .  .  .  .239 

28.  Distribution  of  Capillaries  around  follicles  of  mucous  membrane ;  after  Berres  239 

29.  Portion  of  one  of  Brunner's  Glands ;  after  Allen  Thomson      .             .             .  240 

30.  One  of  the  Hepatic  Caeca  of  Astacus  Afifinis  ;  after  Leidy       .             .             .  241 

31.  Capillary  Network  around  the  follicles  of  Parotid  Gland ;  after  Berres           .  241 

32.  Sebaceous  Glands         ........  243 

33.  Cutaneous  Glandulse  of  external  Meatus  Auditorius ;  after  Wagner    .             .  243 

34.  Development  of  the  Sebaceous  Glands ;  after  Kolliker             .             .             .  244 

35.  Sweat-Gland,  and  the  commencement  of  its  duct         ....  245 

36.  Vertical  section  of  Epidermis,  from  the  palm  of  the  hand ;  after  Erasmus 

Wilson       .........  247 

37.  Vertical  section  of  the  Skin  of  the  Thumb ;  after  Kolliker      .             .             .  247 

38.  Vertical  section  of  the  Skin  of  the  Thigh  of  a  Negro ;  after  Kolliker              .  247 

39.  Pigment-Cells ;  after  Henle      .             .             .             .             .             .             .  249 

40.  Oblique  section  through  the  matrix  of  the  Nail ;  after  Kolliker           .             .  250 

41.  Section  of  skin  on  the  end  of  the  Finger         .....  250 

2* 


XX11  LIST   OF   WOOD-ENGRAVINGS. 

FIG.  PAGE 

42.  Structure  of  Human  Hair       .......  252 

43.  Hair-bulb  of  a  well-developed  Human  Hair  .             .             .             .             .  253 

44.  Development  of  the  Hair-Bulbs ;  after  Kolliker         .  .  .  .254 

45.  Development  of  the  Hair  in  the  Eyebrows     .....  255 

46.  Development  of  Second  Eyelashes  in  an  Infant  of  a  year  old             .             .  255 

47.  Changes  in  the  Hair  at  the  close  of  its  existence       ....  256 

48.  Cells  of  Adipose  Tissue ;  original      ......  257 

49.  Fat  Vesicles  assuming  the  polyhedral  form    .....  257 

50.  Bloodvessels  of  Fat    .             .             .             .             .             .             .            .  258 

51.  Section  of  Branchial  Cartilage  of  Tadpole ;  after  Schwann  .             .             .  260 

52.  Section  of  Fibro-Cartilage ;  after  Lebert        .             .             .             .  .           .  261 

53.  Vessels  between  the  Articular  Cartilage  and  attached  Synovial  Membrane    .  261 

54.  Nutrient  Vessels  of  Cartilage ;  after  Toynbee            .                          .             .262 
65.  Vertical  section  of  Sclerotica  and  Cornea ;  after  Todd  and  Bowman              .  263 

56.  Tubes  of  the  Cornea  of  an  Ox,  injected;  after  Todd  and  Bowman    .             .  264 

57.  Nutrient  Vessels  of  the  Cornea ;  after  Toynbee                                   ,  264 
68.  Structure  of  the  Crystalline  Lens ;  after  Todd  and  Bowman              .            ,  '      265 

59.  Transverse  section  of  Ulna,  deprived  of  its  earth ;  after  Sharpey     .             .  267 

60.  Haversian  canals  in  a  long  Bone ;  after  Todd  and  Bowman   .             .             .  268 

61.  Transverse  section  of  Clavicle ;  original         .....  268 

62.  Lacunae  of  Osseous  substance             ......  269 

63.  Thin  layer  of  fibrous  base  of  Osseous  tissue  ;  after  Sharpey              ,             .  270 

64.  Intramembranous  ossification  in  Parietal  Bone ;  after  Sharpey          .             .  273 

65.  Growing  extremities  of  Spicula  of  bone ;  after  Sharpey         .             .             .  273 

66.  Transverse  section  of  Cartilage  close  to  the  plane  of  Ossification ;  after  Todd 

and  Bowman         ........  274 

67.  Vertical   section  through  Cartilage  and  Incipient  Bone;   after  Todd  and 

Bowman   .........  274 

68.  Vertical  section  of  Cartilage  at  Seat  of  Ossification ;  after  Todd  and  Bowman  274 

69.  Osseous  Network  formed  in  the  Intercellular  Substance  of  Cartilage              .  275 

70.  Transverse  section  of  Growing  Bone1;  after  Sharpey              .             .             .  276 
70*.  Portion  of  border  of  Os  Frontis,  from  a  Human  Embryo;  after  Leidy       .  278 

71.  Mode  of  Ossification  in  Long  Bones;  after  Sharpey  ....  279 

72.  Formation  of  Bone  in  Periosteum       ......  279 

73.  Vertical  section  of  Human  Molar  Tooth ;  after  Man<fl  .  .  .283 

74.  Section  through  the  Fang  of  a  Molar  Tooth ;  after  Czermak              .             .  283 

75.  Transverse  sections  of  Dentine ;  after  Kolliker           .             .             .  284 

76.  Nodular  layer  of  the  Dentine  of  the  Fang;  after  Czermak    .             .             .  284 

77.  Vertical  section  of  Enamel  of  Human  Molar  Tooth ;  after  Owen       .             T  285 

78.  Transverse  section  of  Enamel ;  after  Kolliker            ....  285 

79.  Vessels  of  Dental  Papilla ;  after  Berres         .....  287 

80.  Sections  of  Dentinal  Pulp  in  successive  stages  of  its  development     .             .  288 

81.  Formation  of  Enamel ;  after  Owen    ......  289 

82.  Formation  of  the  Cementum ;  after  Owen      .....  290 

83.  First  stage  of  formation  of  Teeth ;  after  Goodsir      ....  291 

84.  Diagram  illustrating  subsequent  stages  of  formation  of  Teeth ;  after  Goodsir  291 
86.         Do.                                do.                                do.                       after  Goodsir  293 

86.  Replacement  of  Milk-tooth  by  Permanent  tooth  ;  after  Paget           .             .  296 

87.  Capillary  Network  in  Frog's  foot;  after  Wagner        .  .  .  .298 

88.  Capillary  vessels  from  Pia  Mater ;  after  Henle          ....  300 

89.  Formation  of  Capillaries  in  tail  of  Tadpole;  after  Kolliker  .             .             .  301 

90.  Fasciculus  of  fibres  of  Voluntary  Muscle ;  after  Baly            .             .            .  303 

91.  Portion  of  Human  Muscular  Fibre,  separating  into  disks;  after  Bowman     .  304 

92.  Muscular  Fibre  broken  across,  showing  Myolemma;  after  Bowman  .             .  304 

93.  Transverse  section  of  Muscular  Fibres  of  Teal ;  after  Bowman        .             .  305 

94.  Fragment  of  Muscular  Fibre  from  Heart  of  Ox ;  after  Bowman        .             .  305 

95.  Structure  of  ultimate  fibrillse  of  striated  Muscular  Fibre      .             .             .  306 

96.  Muscular  fibre  of  Dysticus,  contracted  in  the  centre ;  after  Bowman             .  307 

97.  Muscular  fibre  of  Skate,  in  different  stages  of  contraction ;  after  Bowman  .  308 

98.  Attachment  of  Tendon  to  Muscular  Fibre  in  Skate ;  after  Bowman  .             .  309 

99.  Non-striated  Muscular  Fibre ;  after  Bowman              ....  309 

100.  Fusiform  cells  of  Smooth  Muscular  Fibre ;  after  Kolliker     .             .             .  310 

101.  Capillary  Network  of  Muscle ;  after  Berres  .....  312 

102.  Terminating  loops  of  Nerves  in  Muscles ;  after  Burdach       .             .             .  313 

103.  Muscular  Fibres  from  Foetal  Pectoralis          .  .  .  .  .314 


LIST   OF   WOOD-ENGRAVINGS.  XX111 

FIG.  PAGE 

104.  Mass  of  Muscular  Fibres  from  Pectoralis  Major  of  Human  Foetus   .             .  314 

105.  Structure  of  Sympathetic  Ganglion;  after  Valentin                .             .             .  335 

106.  Structure  of  Tubular  Nerve-Fibres ;  after  Wagner    ....  336 

107.  Various  forms  of  Ganglionic  Vesicles ;  after  Kolliker             .             .             .  338 

108.  Connection  between  Nerve-Fibres  and  Ganglionic  Cells  ;  after  Wagner          .  340 

109.  Vesicular  and  fibrous  matter  in  the  Gasserian  ganglion;  after  Todd  and 

Bowman    .........  340 

110.  View  of  piece  of  Otic  ganglion  of  Sheep;  after  Valentin      .             .             .  340 

111.  Distribution  of  the  Tactile  Nerves  at  extremity  of  Human  Thumb;  after 

Wagner     .........  341 

112.  Terminal  loops  of  nerve  in  the  pulp  of  a  Tooth ;  after  Valentin        .             .  342 

113.  Structure  of  Pacinian  body ;  after  Sharpey  .             .             .             .             .  343 

114.  Capillary  Network  of  Nervous  Centres ;  after  Berres             .             .             .  344 

115.  Capillary  loops  in  skin  of  Finger ;  after  Berres          ....  344 

116.  View  of  the  Organs  of  Digestion  in  their  whole  length          .             .             .  399 

117.  Muscles  of  the  Tongue,  Palate,  Larynx,  and  Pharynx           .             .             .  401 

118.  Front  view  of  Stomach  distended       .  .  .  .  .405 

119.  Interior  of  the  Stomach          .  .  .  .  .  .  .405 

120.  Interior  of  Stomach  and  Duodenum   .         •   *    j        .         V..<            .             .  406 

121.  Lobule  of  Parotid  Gland ;  after  Wagner          .....  411 

122.  Section  of  mucous  membrane  of  Stomach :  after  Todd      *',             .             .  415 

123.  Sections  of  Stomach-tubes  and  cells ;  after  Todd       ....  415 

124.  Vertical  section  of  a  Stomach-cell,  with  its  tubes       .  .  .  .416 

125.  Portion  of  mucous  membrane  of  Stomach ;  after  Boyd          .             .             .  416 
125*.  Tubular  follicles  of  Pig's  Stomach ;  after  Wasmann             .             .             .  417 

126.  Appearance  of  the  lining  membrane  of  the  Stomach ;  after  Neill      .             .  418 

127.  Section  of  small  Intestine,  containing  glands  of  Peyer            .             .             .  433 

128.  Part  of  one  of  the  patches  of  Peyer's  glands              ....  433 

129.  Portion  of  patch  of  Peyerian  glandulae,  from  Ileum  of  Pig   .             .             .  434 

130.  Vertical  section  of  Peyerian  glandulae,  from  Ileum  of  Pig     .             .             .  434 

131.  Capillary  plexus  of  Intestinal  Villi     .             .             .                       '•    .. -t        .  439 

132.  Inverted  section  of  the  Ileum              .             .             .             .             ,v  1         .  440 

133.  Vessels  of  Intestinal  Villus  of  a  Hare ;  after  Dollinger         .             .             .  440 

134.  Extremity  of  Intestinal  Villus ;  after  Goodsir            .             .             .  \^         .  441 

135.  Extremity  of  Intestinal  Villus  during  absorption ;  after  Kolliker       .             .  441 

136.  Diagram  of  a  Lymphatic  Gland  ;  after  Goodsir           .             .             .             .  451 

137.  Portion  of  Intra-glandular  Lymphatic ;  after  Goodsir         •    .  '•*         .             .  451 

138.  Section  of  Thymus  Gland ;  after  Cooper        .             .         »   *>  '         .             .  460 

139.  The  Anatomy  of  the  Heart     .  .  .  .  .  .  .474 

140.  Haemadynamometer  of  Poisseuille      ......  480 

141.  Web  of  Frog's  foot,  slightly  magnified;  after  Wagner            .             .             .483 
141*.  Haemodrometer  of  Volkmann            .             .             .            V           .  ^-         .  489 
141f.  Lung  of  Triton,  slightly  magnified ;  after  Wagner   .             1..        ;••••-         .  504 

142.  Portion  of  the  same  more  highly  magnified ;  after  Wagner    .             .             .  505 

143.  Capillary  circulation  in  lung  of  living  Triton ;  after  Wagner               .             .  505 
143*.  Small  Bronchial  Tube  laid  open ;  after  Todd  and  Bowman             :  „ . ;          .  506 

144.  The  Larynx,  Trachea,  and  Bronchiae               .             .         VV    >        «.•*          .  507 

145.  Bronchia  and  Bloodvessels  of  the  Lungs         .   •          .  •*     *•*"••'        Y  *>         .  508 

146.  Arrangement  of  Capillaries  in  Human  Lung .             .             .         $•&>•$        .  508 
146*.  Thin  slice  from  pleural  surface  of  Cat's  Lung ;  after  Rossignol       .             .  509 
146|.  Bronchial  termination  in  Lung  of  Dog;  after  Eossignol       .             .             .  509 

147.  Plan  of  augmentation  of  secreting  surface  by  formation  of  processes ;  after 

Sharpey    .........  574 

148.  Plans  of  extension   of  secreting   surface  by  inversion  or  recession;   after 

Sharpey    .........  575 

149.  Lobule  of  Liver  of  Squilla  Mantis ;  after  M  tiller        .             .                      •     .  581 

150.  One  of  the  Hepatic  Caeca  of  Astacus  Affinis ;  after  Leidy     .             .             .  582 

151.  Inferior  surface  of  the  Liver  .....             ^             .  582 

152.  Lobules  of  Liver,  with  branches  of  Hepatic  Vein ;  after  Kiernan      .             .  583 

153.  Horizontal  section  of  Lobules,  showing  arrangement  of  their  Bloodvessels ; 

after  Kiernan         ........  584 

154.  Horizontal  section  of  Lobules,  showing  arrangement  of  their  Bile-ducts ;  after 

Kiernan     .                                        .                          .....  585 

155.  Transverse  section  of  a  Lobule  of  the  Human  Liver ;  after  Leidy     .             .  586 

156.  Portion  of  the  same  more  highly  magnified ;  after  Leidy  ,     .             .             .  586 


XXIV  LIST    OF    WOOD-ENGRAVINGS. 

FIG.  PAGB 

157.  Portion  of  Biliary  Tube  from  Human  liver;  after  Leidy        .             .             .  586 

158.  Lobules  in  a  state  of  anaemia ;  after  Kiernan             ....  588 

159.  Lobules  in  first  stage  of  hepatic  venous  congestion ;  after  Kiernan   .             .  588 

160.  Lobules  in  second  stage  of  hepatic  venous  congestion;  after  Kiernan            .  589 

161.  Lobules  in  a  state  of  portal  venous  congestion ;  after  Kiernan           .             .  589 

162.  .Hepatic  cells  gorged  with  Fat;  after  Bowman            ....  589 

163.  Section  of  Kidney ;  after  Wagner       ......  595 

164.  Portion  of  Tubulus  Uriniferus ;  after  Wagner            ....  595 

165.  Magnified  view  of  small  portion  of  Kidney ;  after  Wagner    .             .             .  596 

166.  Structure  of  Malpighian  Body ;  after  Bowman           ....  596 

167.  Distribution  of  the  Renal  Vessels ;  after  Bowman      ....  598 

168.  Sudoriparous  Gland,  from  palm  of  hand ;  after  Wilson  .  .  .611 

169.  Arrangement  of  apparatus  to  exhibit  the  Nervous  current  of  Electricity ; 

after  Du  Bois-Reymond    .......  638 

170.  Do.                do.                        do.                                do.  639 

171.  Brain  of  Cod;  after  Leuret    .......  647 

172.  A  view  of  the  Great  Sympathetic  Nerve         .             .             .             .             .  •  658 

173.  Roots  of  a  Dorsal  Spinal  Nerve ;  after  Todd  and  Bowman     .             .             .  669 

174.  Transverse  section  of  Human  Spinal  Cord      .....  661 

175.  Transverse  section  of  Spinal  Cord,  at  different  points ;  after  Solly    .             .  663 

176.  Anterior  view  of  Medulla  Oblongata ;  after  Todd  and  Bowman          .             .  676 

177.  Posterior  view  of  Medulla  Oblongata ;  after  Todd  and  Bowman        .            .  676 

178.  Dissection  of  Medulla'  Oblongata         ......  677 

179.  Transverse  section  of  Medulla  Oblongata ;  after  Stilling       .             .             .  678 

180.  Course  of  the  Motor  Tract ;  after  Bell            .....  679 

181.  Course  of  the  Sensory  Tract;  after  Bell         .....  680 
181*.  View  of  the  posterior  part  of  the  Cord        .             .             .  ,          .             .681 

182.  Plan  of  the  distribution  of  the  Fifth  Pair      .....  682 

183.  Ophthalmic  Ganglion  ........  684 

184.  Nerves  of  the  Orbit;  after  Arnold      ......  686 

185.  Diagram  of  the  distribution  of  the  Seventh  Pair       ....  687 

186.  Diagram  of  the  distribution  of  the  Eighth  Pair;  after  Erasmus  Wilson         .  689 

187.  View  of  the  distribution  of  the  Glosso-pharyngeal,  Pneumogastric,  and  Spinal 

Accessory  Nerves,  or  the  Eighth  Pair      .....  689 

188.  A  view  of  the  course  and  distribution  of  the  Hypoglossal  or  Ninth  Pair       .  692 
188*.  Cerebral  connection  of  the  Cerebral  Nerves  694 

189.  Sensory  Ganglia          .             ...             .             .             .             .             .  703 

189*.  Dissection  of  a  Brain  hardened  in  spirits  of  wine   ....  704 

190.  A  view  of  the  Optic  Nerve  and  the  origins  of  seven  other  pairs         .             .  715 

191.  Course  of  the  Fibres  in  the  Chiasma ;  after  Todd  and  Bowman         .             .  717 

192.  Origin  and  distribution  of  the  Portio  Mollis  of  Seventh  Pair,  or  Auditory 

Nerve 718 

193.  Cerebellum     .  .  .  .  .  .  .  .  .729 

194.  Analytical  diagram  of  the  Encephalon ;  after  Mayo  ....  730 
194*.  Connection  between  the  Motor  Tract  and  the  Cerebellum    .             .             .  731 
194f .  Course  and  connection  of  Fibres  of  Corpus  Callosum           .             .             .  743 
194J.  Course  of  Fibres  of  superior  longitudinal  Commissure        .             .             .  744 
194|.  Relations  of  the  Fornix        .......  745 

195.  Diagram  of  mutual  relations  of  principal  Encephalic  Centres,  as  shown  in 

vertical  section     .             .             .             .             .             .             .             .  756 

196.  Capillary  Network  at  margin  of  Lips ;  after  Berres  ....  858 

197.  Dorsal  surface  of  Tongue ;  from  Soemmering              ....  864 

198.  Simple  Papillae  near  the  base  of  the  Tongue ;   after  Todd  and  Bowman        .  865 

199.  Vertical  section  of  one  of  the  circumvallate  Papillae ;  after  Todd  and  Bowman  865 

200.  Compound  and  simple  Papillae  of  Foramen  Ccecum ;  after  Todd  and  Bowman  866 

201.  Capilkry  Network  of  fungiform  Papillae  of  Tongue;  after  Berres     .             .  866 

202.  Fungiform  Papilla,  with  its  simple  Papillae  and  Vessels ;   after  Todd  and 

Bowman    .                                      ...*...  867 

203.  Various  forms  of  the  conical  Papillae ;  after  Todd  and  Bowman        .             .  867 

204.  Section  of  filiform  and  fungiform  Papillae ;  after  Todd  and  Bowman               .  867 

205.  Secondary  Papilla  of  the  conical  class,  treated  with  acetic  acid ;  after  Todd 

and  Bowman                                    .             .             .             .             .             .  868 

206.  Distribution  of  the  Olfactory  Nervl  on  Septum  Nasi;  after  Erasmus  Wilson  871 

207.  Olfactory  filaments  of  the  Dog ;  after  Todd  and  Bowman      .             .             .  872 

208.  Longitudinal  section  of  globe  of  the  Eye       .....  875 


LIST   OP   WOOD-ENGRAVINGS.  XXV 

PIG.  PAGE 

209.  Ciliary  Muscle ;  after  Todd  and  Bowman       .....  876 

210.  Capillary  Network  of  Retina ;  after  Berres  .....  87<'| 

211.  Part  of  Retina  of  Frog           .......  878 

212.  Vertical  section  of  Human  Retina  and  Hyaloid  membrane ;  after  Todd  and 

Bowman    .........  878 

213.  Membrane  of  Jacob ;  after  Jacob       ......  879 

214.  Stereoscopic  figures ;  original             ......  886 

215.  Stereoscopic  projections  of  Pyramid ;  after  Wheatstone        .             .             .  887 

216.  Diagram  illustrating  Visual  Angle  ;  original               ....  889 

217.  General  section  of  the  Ear ;  after  Scarpa       .....  899 

218.  Auditory  Nerve  taken  out  of  the  Cochlea       .....  895 

219.  Magnified  view  of  Lamina  Spirales     .  .  •    .  .895 

220.  Diagram  of  inner  wall  of  Tympanum ;  after  Todd  and  Bowman        .             .  896 

221.  Membrana  Tympani   ........  900 

222.  Ossicles  of  the  Ear ;  after  Arnold       ......  900 

223.  Labyrinth  of  left  side              .                         902 

224.  Distribution  of  Nerves  in  the  Ampullae           .....  903 

225.  Ampullae  of  External  Semicircular  Membranous  Canal          .                         .  903 

226.  Axis  of  Cochlea  and  Lamina  Spiralis              .....  904 

227.  Cochlea  of  a  new-born  Infant              ......  904 

228.  Cochlea  divided  through  the  centre  of  Modiolus ;  after  Breschet       .             .  905 

229.  View  of  Left  Ear        ........  906 

230.  Anterior  view  of  External  Ear,  Meatus  Auditorius,  &c.                      .             .  906 

231.  External  and  sectional  views  of  the  Larynx ;  after  Willis      .             .             .  925 

232.  Bird's-eye  view  of  Larynx  from  above  ;  after  WiUis  .  .  .926 

233.  Posterior  view  of  Larynx ;  after  Sharpey      .....  926 

234.  Diagram  of  Direction  of  Muscular  Forces  of  Larynx ;  after  Willis  .             .  927 

235.  Artificial  Glottis ;  after  Willis             ......  931 

236.  Diagram  representing  the  Generative  Process  in  Plants ;  original     .             .  950 

237.  The  Testicle  injected  with  Mercury ;  after  Lauth      .  .  .  .952 

238.  Minute  structure  of  Testis     .......  952 

239.  Human  Testis  injected  with  Mercury ;  after  Lauth    .  .  .  .953 

240.  Diagram  of  the  structure  of  the  same            .             .             .    '         .             .  953 

241.  Diagram  of  a  Graafian  Vesicle  containing  an  Ovum  .          '.,/"•        .             .  957 

242.  Constituent  parts  of  Mammalian  Ovum ;  after  Coste                           .             .  958 

243.  Ovarium  of  Rabbit,  at  period  of  heat;  after  Pouchet            .             .             .  959 

244.  Cells  forming  original  substance  of  Corpus  Luteum ;  after  Pouchet .             .  963 

245.  Successive  stages  of  formation  of  Corpus  Luteum  ;  after  Pouchet    .             .  964 

246.  Corpora  Lutea  of  different  periods     ......  965 

247.  Ovarian  Ovum  from  a  Bitch  in  heat   ......  971 

248.  Section  of  lining  membrane  of  Uterus  at  commencement  of  Pregnancy ;  after 

Weber       .  .  .  .  .  .  .  .  .972 

249.  The  same,  more  enlarged ;  after  Weber          .             ,            .             .             .  973 

250.  Thin  segments  of  Human  Decidua ;  after  Sharpey    ....  973 

251.  First  stage  of  formation  of  Decidua  Reflexa ;  after  Coste      .            \             .  973 

252.  More  advanced  stage  of  the  same ;  after  Coste          ....  974 

253.  Extremity  of  a  Villus  magnified  200  diameters ;  after  Weber            .             .  975 

254.  Portion  of  ultimate  ramifications  of  Umbilical  vessels ;  original        .             .  975 

255.  Extremity  of  a  Placental  Villus;  after  Weber            .  976 

256.  External  membrane  and  cells  of  Placental  Villus ;  after  Goodsir       .             .  976 

257.  Diagram  of  arrangement  of  Placental  Decidua ;  after  Goodsir           .             .  976 

258.  Diagram  of  structure  of  the  Placenta             .             .             .             .  977 

259.  Diagram  of  Placental  Cavity ;  after  Reid       .....  977 

260.  Cleaving  of  the  Yelk  after  fecundation  in  ovum  of  Ascaris ;  after  Kolliker  and 


261.  Subdivision  of  Yelk  in  Mammalian  Ovum      .....  988 

262.  Plan  of  early  Uterine  Ovum ;  after  Wagner  .  .  .  .  .  991 

263.  Diagram  of  Ovum,  showing  formation  of  Amnion;  after  Wagner      .  .  991 

264.  The  same,  still  more  advanced,  the  Allantois  beginning  to  appear;  after 

Wagner     .  «;  ,  .  .  .  .  .  .  993 

265.  Diagram  of  Ovum  in  second  month,  showing  incipient  formation  of  Placenta ; 

after  Wagner         ...  ....  993 

266.  Diagram  of  Circulation  in  Human  Embryo  and  its  appendages  ;  after  Coste  994 

267.  Anterior  view  of  same ;  after  Coste  ......  994 

268.  Diagram  illustrating  Foetal  Circulation ;  after  Erasmus  Wilson          .  .  997 


XXVI  LIST    OF   WOOD-ENGRAVINGS. 

FIG.  PAGE 

269.  Embryo  Dog,  showing  junction  of  umbilical  vesicle  with  intestinal  canal       .  998 

270.  Origin  of  Liver  from  intestinal  wall ;  after  Miiller     ....  999 

271.  First  appearance  of  the  Lungs ;  after  Wagner           .             .             .             .  1000 

272.  State  of  urinary  and  genital  apparatus  in  early  embryo  of  Chick ;  after  Miiller  1001 

273.  Urinary  and  generative  organs  of  a  Human  Embryo              .             .             .  1004 

274.  Elements  of  a  Vertebra ;  after  Owen              ...             .             .             .  1005 

275.  Human  Embryo  of  sixth  week ;  after  Wagner           ....  1009 

276.  Brain  of  Human  Embryo  at  twelfth  week ;  after  Tiedemann             .             .  1010 

277.  Diagram  representing  the  comparative  viability  of  the  male  and  female  at 

different  ages ;  after  Quetelet       .  .  .  .  .1016 

278.  Diagram  representing  the  comparative  heights  and  weights  of  the  male  and 

female  at  different  ages ;  after  Quetelet  .....  1017 

279.  Mammary  Gland         ........  1018 

280.  Vertical  section  of  Mammary  Gland  .  .  .  .  .  .1018 

281.  Distribution  of  Milk-Ducts  in  mammary  glands ;  after  Sir  A.  Cooper            .  1019 

282.  Termination  of  a  portion  of  Milk-Duct  in  a  cluster  of  follicles ;  after  Sir  A. 

Cooper      .                          .......  1020 

283.  Mammary  Follicles  with  contained  cells ;  after  Lebert           .             .             .  1020 

284.  Views  of  Prognathous  Skull ;  after  Prichard              ....  1033 

285.  Views  of  Pyramidal  Skull ;  after  Prichard    .....  1034 

286.  View  of  Oval  Skull;  after  Prichard  .            .....  1034 


PLATE.  1 


T.  Sindair!s  LM'., 


EXPLANATION  OF  PLATES. 


PLATE   I. 

FIG. 

1.  Spermatozoa  of  Man;  A,  viewed  on  the  surface;  B,  viewed  edgewise  (g  958). 

2.  Vesicles  of  evolution  from  the  seminal  fluid  of  the  Dog ;  A,  B,  c,  single  vesicles  of  dif- 

ferent sizes ;  D,  single  vesicle  within  its  parent-cell ;  E,  parent-cell  inclosing  seven 
vesicles  of  evolution  ($  959). 

3.  Development  of  Spermatozoa  within  the  vesicles  of  evolution ;  A,  B,  vesicles  containing 

spermatozoa  in  process  of  formation ;  c,  D,  spermatozoa  escaping  from  the  vesicles 
(2  959). 

[The  three  preceding  figures  are  after  Wagner  and  Leuckardt  ("Cyclop,  of  Anatomy 
and  Physiology,"  Art.  "Semen").] 

4.  Thin  slice  of  the  ovarium  of  a  Sow  three  weeks  old,  showing  the  Graafian  vesicles  or 

ovisacs  imbedded  in  a  fibro-cellular  stroma.  The  ovisacs  are  filled  with  cells,  in 
the  midst  of  which  one  large  one  may  be  specially  distinguished ;  this,  which  is 
the  germinal  vesicle,  is  surrounded  by  minute  granules,  which  constitute  the  first 
indication  of  the  yelk  (|  963). 

5.  Ovum  of  a  Rabbit,  showing  the  vitelline  mass  almost  entirely  converted  into  distinct 

cells,  of  which  those  at  the  surface  are  pressed  against  each  other  and  against  the 
zona  pellucida,  so  as  to  assume  an  hexagonal  form.  The  dark  portion  consists  of 
a  mass  of  vitelline  spheres,  which  has  not  undergone  this  conversion  (§  996). 

6.  Ovum  of  the  Rabbit,  seven  days  after  impregnation,  viewed  on  a  black  ground.     The 

outer  membrane  is  the  chorion,  on  which  are  seen  incipient  villosities.  Within  this 
is  the  blastodermic  vesicle,  at  the  summit  of  which  is  the  projection  formed  by  the 
area  aerminativa ;  and  from  this  the  mucous  layer  of  the  germinal  membrane  is 
seen  to  extend  over  about  one-third  of  the  surface  of  the  contained  yelk  (g  996). 

7.  Portion  of  the  germinal  membrane,  taken  from  the  area  aerminativa,  to  show  the  two 

layers  of  which  it  is  composed ;  the  serous,  or  animal  layer,  is  turned  back,  so  as 
to  show  the  mucous,  or  vegetative,  layer  in  situ.  In  the  latter  is  seen  the  primitive 
trace  (§  996). 

8.  Portion  of  the  serous  layer  of  the  germinal  membrane,  highly  magnified ;  showing  that 

it  is  made  up  of  nucleated  cells,  united  by  intercellular  substance,  and  filled  with 
minute  molecules  (§  996). 

9.  Portion  of  the  mucous  layer  of  the  germinal  membrane,  highly  magnified ;  showing  that 

it  is  made  up  of  cells  whose  borders  are  more  distinct  and  more  closely  applied  to 
each  other  than  those  of  the  serous  layer,  and  whose  contents  are  more  transparent 
(8  996). 

[The  six  preceding  figures  are  after  Bischoff  ("Entwickelungsgeschichte  der  Siiuge- 
thiere,"  &c.  (1842);  "des  Kanincheneies"  (1842);   "des  Hunde-eies"  (1845).] 


XXV111  EXPLANATION   OF   PLATES. 

FIG. 

10.  Gravid  uterus  of  a  Woman,  who  had  committed  suicide  in  the  seventh  week  of  preg- 
nancy, laid  open ;  a,  os  uteri  internum ;  b,  cavity  of  the  cervix ;  c,  c,  c,  c,  the  four 
flaps  of  the  body  of  the  uterus  turned  back;  d,  d,  d,  inner  surface  of  uterine 
decidua ;  e,  e,  decidua  reflexa ;  /,  /,  external  villous  surface  of  the  chorion ;  g, 
internal  surface  of  the  chorion ;  h,  amnion ;  i,  umbilical  vesicle ;  k,  umbilical  cord ; 
I,  embryo;  m,  space  between  chorion  and  amnion  (§|  919-921,  and  938,  939). 
[After  Wagner  ("Icones  Physiologic^").] 


PLATE    II. 

11.  Uterine  Ovum  of  Rabbit,  showing  the  Area  Pellucida,  with  the  primitive  trace  ($  937). 

12.  More  advanced  ovum,  showing  the  incipient  formation  of  the  Vertebral  column,  and 

the  dilatation  of  the  primitive  groove  at  its  anterior  extremity  ($  937). 

13.  More  advanced  embryo,  seen  on  its  ventral  side,  and  showing  the  first  development  of 

the  Circulating  apparatus.  Around  the  Vascular  Area  is  shown  the  terminal  sinus 
0,  a,  a.  The  blood  returns  from  this  by  two  superior  branches,  b,  b,  and  two  in- 
ferior, c,  c,  of  the  omphalo-meseraic  veins,  to  the  heart,  d;  which  is,  at  this  period, 
a  tube  curved  on  itself,  and  presenting  the  first  indication  of  a  division  into  cavi- 
ties. The  two  aortic  trunks  appear,  in  the  abdominal  region,  as  the  inferior 
vertebral  arteries,  e,  e ;  from  which  are  given  off  the  omphalo-meseraic  arteries, 
/,  /,  which  form  a  network  that  distributes  the  blood  over  the  vascular  area.  In 
the  cephalic  region  are  seen  the  anterior  cerebral  vesicles,  with  the  two  ocular 
vesicles,  g  (\\  938,  940). 
[The  three  preceding  figures  are  from  the  works  of  Bisehoff  previously  cited.] 


PLATE.  II. 


Tig.  12. 


T.Simiairs  Vth.PftLLa. 


INTRODUCTION. 


THE  object  of  the  science  of  Physiology  is  to  bring  together,  in  a  systematic 
form,  the  phenomena  which  normally  present  themselves  during  the  existence 
of  living  beings;  and  to  classify  and  compare  these  in  such  a  manner,  as  to 
deduce  from  them  those  general  Laws  or  Principles  which  express  the  conditions 
of  their  occurrence,  and  to  determine  the  Causes  to  which  they  are  attributable. 

The  term  "  Law"  having  been  frequently  applied  to  physical  and  physiological 
phenomena,  in  a  manner  very  different  from  that  which  sound  philosophy  sanc- 
tions, it  is  desirable  to  explain  the  acceptation  (believed  by  the  author  to  be  the 
only  legitimate  one)  in  which  it  is  here  employed.  Viewed  in  their  scientific 
aspect,  the  so-called  Laws  of  Nature  are  nothing  else  than  general  expressions 
of  the  conditions  under  which  certain  assemblages  of  phenomena  occur,  so  far 
as  those  conditions  are  known  to  us.  Thus  the  law  of  Gravitation  in  General 
Physics  (the  most  comprehensive  of  any  with  which  we  are  acquainted),  is 
nothing  else  than  a  simple  expression  of  the  fact,  that,  under  all  circumstances, 
two  masses  of  matter  will  attract  each  other,  with  forces  directly  proportional 
to  their  respective  bulks,  and  inversely  as  the  square  of  their  distances.  So, 
again,  the  law  of  Cell-growth,  which  seems  to  hold  nearly  the  same  rank  in 
Physiology  with  that  of  Gravitation  in  Physics,  embodies  these  two  general 
facts  (1),  that  all  organized  beings  originate  in  cells,  and  (2),  that  the  various 
functions  of  life  are  carried  on,  even  in  the  adult  condition,  by  the  continued 
growth  and  development  of  cells. 

It  is  a  very  common  fallacy,  however,  to  assume  that  we  have  sufficiently 
accounted  for  a  phenomenon,  when  we  have  referred  it  to  a  "general  law." 
Thus  if  a  man  be  asked  why  a  stone  falls  to  the  earth,  he  commonly  considers 
that  he  gives  a  satisfactory  explanation  when  he  replies,  "  Because  of  the  Law  of 
gravitation."  But  it  must  be  remembered  that  this  "  law  of  gravitation"  is  a 
law,  that  is,  a  generalized  expression  of  facts,  only  because  all  stones  fall  to  the 
3 


34  INTRODUCTION. 

earth,  and  all  other  masses  of  matter  (so  far  as  we  know)  towards  each  other ; 
therefore,  to  say  that  a  stone  falls  to  the  earth  because  of  the  law  of  gravitation, 
is  merely  to  say  that  two  bodies  are  attracted  together  because  all  others  are — 
which  is  obviously  nothing  else,  than  an  extension  of  the  statement  from  the 
particular  to  the  general  fact.  It  cannot,  indeed,  be  kept  too  constantly  in  view, 
"  that  in  science,  those  who  speak  of  explaining  any  phenomenon  mean  (or  should 
mean)  pointing  out  not  some  more  familiar,  but  merely  some  more  general  phe- 
nomenon, of  which  it  is  a  partial  exemplification ;"  the  explanation  being  ac- 
counted most  complete,  when  the  conditions  of  such  general  phenomenon  can 
be  expressed  in  the  precise  form  of  a  "  law,"  with  which  those  of  the  particular 
case  can  be  shown  to  accord,  and  from  which,  therefore,  its  occurrence  may  be 
predicted  deductively.  The  whole  problem  of  the  scientific  investigation  of 
Nature  may,  indeed,  be  thus  stated  :  "  What  are  the  fewest  assumptions,  which, 
being  granted,  the  order  of  nature  as  it  exists  would  be  the  result  ?  What  are 
the  fewest  general  propositions,  from  which  all  the  uniformities  existing  in  nature 
could  be  deduced  F"1 

In  its  scientific  acceptation,  therefore,  a  Law  of  Nature  must  be  admitted  to 
possess  no  coercive  power  whatever ;  and  to  speak  of  phenomena  as  being  governed 
by  laws,  is  altogether  incorrect.  The  only  sense  in  which  this  form  of  expression 
can  be  admitted  to  have  any  true  meaning,  is  when  the  law  is  the  expression  of 
a  will,  which  is  potent  to  produce,  to  direct,  or  to  restrain  the  actions  to  which 
it  relates.  Thus  the  laws  of  a  State  are  expressions  of  the  Will  of  the  govern- 
ing power,  intended  to  regulate  the  conduct  of  the  community  over  which  it 
rules ;  and  they  become  entirely  inoperative,  from  the  moment  when  that  power 
ceases  to  be  effectual  to  carry  out  the  purposes  which  it  has  thus  announced. 
So  then,  if  we  recognize  in  the  Universe  the  existence  of  a  sustaining  and  con- 
trolling Power,  we  may  regard  the  Laws  of  Nature  which  Man  has  discovered, 
as  expressions  of  the  plan  (so  far  as  he  has  succeeded  in  unveiling  it)  according 
to  which  that  Power  acts ;  and  we  may  then  legitimately  speak  of  the  phenomena 
of  Nature  as  governed  by,  or  rather  taking  place  according  to,  Laws — it  being 
always  borne  in  mind,  however,  that  these  laws  are  mere  human  expressions  of 
the  plan  on  which  the  Divine  Power  seems  to  operate,  and  may  be  not  only  very 
imperfect,  but  also  very  incorrect.  The  moment,  then,  that  we  attribute  to  Laws 
of  Nature  a  coercive  efficacy,  we  pass  from  the  domain  of  Natural  Science  into 
that  of  Theology;  and  imply,  if  we  do  not  formally  recognize,  the  existence  of 
a  Power,  of  whose  modus  operandi  these  laws  are  the  presumed  exponents.3 

1  See  "Elements  of  Logic,"  by  Mr.  J.  S.  Mill,  3d  ed.  vol.  i.  p.  486. 

2  The  neglect  of  this  distinction  has  led  to  many  fallacies ;  not  the  least  of  which  is,  that 


INTRODUCTION.  35 

The  sense  in  which  the  term  Cause,  also,  is  to  be  employed,  should  be  clearly 
understood  at  the  outset  of  any  scientific  inquiry  that  involves  its  use;  more 
especially,  since  there  is  a  considerable  discrepancy  between  the  popular  accepta- 
tion of  the  word,  and  the  meaning  which  is  now  generally  assigned  to  it  by  logi- 
cians ;  and  it  is  peculiarly  necessary  for  the  correctness  of  Medical  reasoning, 
that  its  import  should  be  definitely  settled.  When  the  "  cause"  of  any  event  is 
spoken  of,  in  common  parlance,  we  certainly  attach  to  the  term  the  idea  of  power, 
at  the  same  time  that  we  include  the  notion  of  the  conditions  under  which  that 
power  operates;  and  this  practical  view  of  the  case  will  be  found  (as  the  Author 
believes)  to  be  the  correct  one.  On  the  other  hand,  the  logician  draws  a  dis- 
tinction between  the  "efficient"  and  the  "physical"  cause  of  any  phenomenon, 
dismisses  the  former  as  a  matter  with  which  scientific  inquiry  is  not  legitimately 
concerned,  and  applies  himself  to  the  consideration  of  the  latter  alone,  which  he 
defines  to  be  "  the  antecedent,  or  the  concurrence  of  antecedents,  on  which  it  is 
invariably  and  unconditionally  consequent."  (Mill,  op.  cit.)  But  when  this 
assemblage  of  antecedents  is  analyzed,  it  is  uniformly  found  that  they  may  be 
resolved  into  two  categories,  which  may  be  distinguished  as  the  dynamical  and 
the  material :  the  former  supplying  the  force  or  power  to  which  the  change  must 
be  attributed ;  whilst  the  latter  afford  the  conditions  under  which  that  power  is 
exerted.  Thus  in  a  Steam-Engine,  we  see  the  dynamical  agency  of  Heat  made 
to  produce  mechanical  power,  by  the  mode  in  which  it  is  applied — first,  to  impart 
a  mutual  repulsion  to  the  particles  of  water,  and  then,  by  means  of  that  mutual 
repulsion,  to  give  motion  to  the  various  solid  parts  of  which  the  machine  is  coin- 
posed.  And  thus,  if  asked  what  is  the  cause  of  the  movement  of  the  Steam- 
Engine,  we  distinguish  in  our  reply  between  the  dynamical  condition  supplied 
by  the  Heat,  and  the  material  condition  (or  assemblage  of  conditions)  afforded 
by  the  collocation  of  the  boiler,  cylinder,  piston,  valves,  &e.  So,  again,  if  we  are 
asked  what  is  the  cause  of  the  movement  of  a  spinning-jenny,  we  refer  it  to  its 
connection  by  bands  or  wheels  with  some  shaft,  which  itself  derives  its  power  to 
move  from  a  steam-engine  or  water-wheel ;  these  material  collocations  here  again 
serving  to  supply  the  conditions  under  which  that  Force  becomes  operative.  In 
like  manner,  if  we  inquire  into  the  causes  of  the  germination  of  a  seed,  which 
has  been  brought  to  the  surface  of  the  earth,  after  remaining  dormant,  through 
having  been  buried  deep  beneath  the  soil,  for  (it  may  be)  thousands  of  years — 
we  are  told  that  the  phenomenon  depends  upon  warmth,  moisture,  and  oxygen : 

the  discovery  of  a  scientific  law  affords  a  sufficient  account  of  the  occurrence  of  natural 
phenomena ;  and  that  the  notion  of  the  personal  agency  of  the  Deity  in  their  production  is, 
therefore,  an  unwarrantable  assumption. 


36  INTRODUCTION. 

but  out  of  these  we  single  warmth  as  the  dynamical  condition;  whilst  the 
oxygen  and  the  water,  with  the  organized  structure  of  the  seed  itself,  and  the 
organic  compounds  which  are  stored  up  in  its  substance,  constitute  the  material. 
A  strictly  scientific  inquiry,  then,  must  recognize  Dynamical  agency,  as  well 
as  Material  condition ;  and  it  will  be  found  that  this  is  peculiarly  requisite  in 
the  Science  of  Life,  which  has  been  pursued  by  some  as  if  it  were  a  sufficient 
account  of  every  phenomenon  not  otherwise  explicable,  to  refer  it  to  a  "  vital 
principle;"  whilst  others  have  endeavored  to  reduce  all  Physiological  causation 
to  a  set  of  material  conditions,  maintaining  that  Life  entirely  depends  on  "  organi- 
zation/' and  that  the  hypothesis  of  a  vital  principle  is  consequently  unnecessary 
and  unphilosophical.  Others,  again,  who  have  recognized  the  operation  of  Phy- 
sical and  Chemical  agencies  in  the  living  body,  have  maintained  that  all  Vital 
action  is  but  a  peculiar  manifestation  of  heat,  mechanical  power,  chemical  affinity, 
and  the  like ;  and  have  thus  attempted  to  break  down  the  barrier  between  the 
Organized  and  the  Inorganic  creation.  The  Author  has  elsewhere1  endeavored 
to  show,  that  we  have  evidence  of  the  operation  of  a  power  in  the  living  body, 
whose  manifestations  are  so  different  from  those  of  any  of  the  Physical  Forces, 
that  we  cannot  reasonably  refrain  from  giving  it  a  distinctive  designation ;  and 
that  this  "  Vital  Power"  may  exert  itself  in  a  great  variety  of  modes,  and  may 
consequently  produce  a  great  variety  of  phenomena,  according  to  the  material 
conditions  of  its  operation,  just  as  (though  the  comparison  be  somewhat  clumsy) 
the  mechanical  power  which  turns  the  engine-shaft  in  an  extensive  factory,  is 
rendered  efficient  for  an  immense  variety  of  purposes,  according  to  the  construc- 
tion and  arrangement  of  the  several  machines  through  which  it  is  distributed. 
And  further,  he  has  attempted  to  prove,  that  the  source  of  this  Vital  Power  is 
to  be  found,  not  in  the  organization  of  the  being  itself,  but  in  the  forces  which 
operate  upon  it  ab  externo;  and  that  it  has  the  same  close  and  intimate  relation 
with  the  Heat,  Electricity,  Chemical  Affinity,  and  other  agencies  of  the  In- 
organic world,  which  they  have  been  proved  to  have  with  each  other :  so  that, 

just  as  Heat  acting  upon  water  generates  Mechanical  force,  or  when  applied  to 

\ 
a  certain  combination  of  metals  excites  Electricity,  so,  when  brought  to  bear 

upon  a  torpid  animal  or  upon  a  seed  (in  which  the  material  conditions  of  this 
activity  are  present),  it  manifests  itself  as  Vital  Force,  and  is  the  immediate 
dynamical  condition  of  the  phenomena  of  growth,  development,  &c. 

But  further,  the  term  Cause  has  a  Theological  as  well  as  a  Scientific  sense;  and, 
like  the  two  usages  of  the  term  Law,  these  two  acceptations  are  perfectly  har- 

1  See  his  Memoir  "On  the  Mutual  Relations  of  the  Vital  and  Physical  Forces,"  in  the 
Philosophical  Transactions  for  1850. 


INTRODUCTION.  37 

monious,  although  in  themselves  different.  "When  in  scientific  inquiry  we  have 
traced  a  multitude  of  complex  phenomena  up  to  a  single  force,  and  have  shown 
that  their  variety  is  due  only  to  the  diversity  of  the  conditions  under  which  that 
force  is  operating,  we  still  have  to  ascertain  the  source  of  this  force  ;  and  it  is 
no  sufficient  account  of  it  to  show  that  it  is  but  a  metamorphosed  form  of 
some  other  force.  We  may  even  be  led  by  Science  to  look  upon  all  the  phe- 
nomena of  the  Universe  as  the  results  of  the  operation  of  a  single  dynamical 
agent,  varied  in  the  modes  of  its  manifestation  according  to  the  nature  of  the 
mechanism  (so  to  speak)  which  it  puts  in  action.  The  existence  of  this  force, 
causa  causarum,  still  remains  unaccounted  for;  but  at  this  point  Physical 
Science  ends,  and  the  question  becomes  one  of  an  entirely  different  order. 
The  inquiring  mind  cannot  stop  here;  and  if  it  seek  a  solution  in  its  own  ex- 
perience, it  is  led  by  the  consciousness  that  by  its  own  volition  it  can  give 
rise  to  a  force  which  is  capable  of  operating  upon  the  material  world,  to  look  to 
an  Intelligent  Will  as  the  ultimate  spring  of  all  those  changes  for  which  it 
can  find  no  other  source,  and  to  regard  the  Forces  of  the  Universe  in  general 
as  so  many  modes  of  operation  of  the  one  Omnipotent  and  Omnipresent  Mind. 
Viewed  under  this  aspect,  therefore,  all  the  phenomena  of  Nature  which  have 
not  their  origin  in  the  mental  power  of  subordinate  beings,  must  be  considered 
as  the  immediate  exponents  of  the  Will  of  the  Creator ;  and  thus  again  we  are 
led  to  regard  their  so-called  "Laws,"  as  but  Man's  expression  of  the  condi- 
tions under  which  the  Divine  Power  appears  continually  operative  in  producing 
them. 

In  a  purely  Scientific  Treatise,  however,  it  is  in  the  scientific  sense  alone  that 
the  terms  " Cause"  and  "Law"  are  to  be  understood;  and  wherever  they  occur 
in  the  following  work,  therefore,  the  Author  would  imply  by  the  former  the 
exercise  of  a  force  or  power,  Physical  or  Vital,  operating  under  certain  definite 
material  conditions ;  whilst  by  the  latter  he  would  designate  every  such  general 
exponent  of  those  conditions  under  which  a  force  operates,  as  may  enable  the 
results  to  be  determined  beforehand.  Thus  the  Law  of  Gravitation  defines  in 
general  terms  that  constant  relation  between  the  bulk  and  the  distance  of  masses 
of  matter,  on  the  one  hand,  and  the  amount  of  force  which  is  developed  by  their 
mutual  attraction,  on  the  other,  which  enables  us,  by  an  acquaintance  with  the 
particulars  of  the  former,  to  predicate  those  of  the  latter.  And  the  Law  of 
Definite  Proportions  expresses  in  general  terms  that  relation  between  the  "com- 
bining equivalents"  of  different  substances,  which  enables  us,  when  we  apply  it 
to  particulars,  to  determine  precisely  how  much  of  a  compound  substance  will 
be  decomposed  by  the  force  of  Chemical  attraction,  which  a  given  amount  of 


38  INTRODUCTION. 

another  substance  may  exert  upon  one  of  its  components,  and  what  will  be  the 
nature  and  constitution  of  the  product. 

In  order  to  determine  the  most  general  laws  of  Physiological  Science,  a  very 
extensive  comparison  is  requisite.  Principles,  which  might  seem  of  paramount 
importance  in  regard  to  one  group  of  living  beings,  are  often  found,  on  a  more 
extended  review,  to  be  quite  subordinate.  For  example,  the  predominance  of 
the  Nervous  System  in  the  higher  classes  of  Animals,  and  its  evidently  close 
connection  with  many  of  the  functions  of  life,  have  led  several  Physiologists  to 
the  opinion,  that  its  influence  is  essential  to  the  performance  of  the  functions  of 
Nutrition,  Secretion,  &c. ;  but,  on  turning  our  attention  to  the  Vegetable  king- 
dom, in  which  nothing  analogous  to  a  nervous  system  can  be  proved  to  exist, 
we  find  these  functions  going  on  with  even  greater  activity  than  in  animals.  It 
is  clear,  therefore,  they  may  be  performed  without  it ;  and,  on  a  closer  examina- 
tion of  the  phenomena  presented  by  Animals,  it  is  seen  that  these  may  be 
explained  better,  on  the  principle  that  the  nervous  system  has  a  powerful  influ- 
ence on  such  actions,  than  on  the  idea  that  it  affords  a  condition  essential  to 
them.  Recent  inquiries  have  shown,  that  the  agents  immediately  concerned  in 
these  operations  are  of  the  same  nature  in  both  kingdoms ;  the  separation  of  the 
nutrient  materials  from  the  circulating  fluid,  or  the  elimination  of  substances 
which  are  to  be  withdrawn  from  it,  being  performed  in  the  Animal,  as  in  the 
Plant,  by  cells,  in  the  manner  to  be  explained  hereafter.  This  is  only  one  out 
of  many  instances,  which  it  would  be  easy  to  adduce,  in  proof  of  the  necessity 
of  bringing  together  all  the  phenomena  of  the  same  kind,  in  whatever  class  of 
living  beings  they  may  be  presented,  before  we  attempt  to  erect  any  general 
principles  in  Physiology. 

The  object  of  the  present  treatise,  however,  is  not  to  follow  out  such  an  in- 
vestigation, which  has  been  pursued,  as  fully  as  his  limits  would  allow,  in  the 
Author's  " Principles  of  Physiology,  General  and  Comparative;"  but  to  show 
the  detailed  application  of  the  principles  of  which  Physiological  science  may 
now  be  said  to  consist,  to  the  phenomena  exhibited  by  the  Human  organism, 
during  the  continuance  of  health  or  normal  life.  These  phenomena,  when  they 
occur  in  a  disturbed  or  irregular  manner,  constitute  disease  or  abnormal  life ; 
and  become  the  subjects  of  the  science  of  Pathology.  It  is  impossible  to  draw 
a  precise  line  of  demarcation  between  the  states  of  health  and  disease ;  since 
many  variations  occur,  which  do  not  pass  the  limits  of  what  must  be  called  in 
some  individuals  the  normal  state,  but  which  must  be  regarded  as  decidedly 
abnormal  conditions  in  others.  The  sciences  ef  Physiology  and  Pathology, 
therefore,  are  very  closely  related;  and  neither  can  be  pursued  with  the  highest 


INTRODUCTION.  39 

prospect  of  success,  except  in  connection  with  the  other.  It  is  now  coming  to 
be  generally  felt,  that  our  fundamental  ideas  of  healthy  vital  action  must  rest 
on  the  knowledge  of  the  structure,  composition,  and  properties  of  the  minutest 
portions  of  the  fabric;  and  in  like  manner,  our  fundamental  notions  of  the 
changes  in  which  disease  essentially  consists,  are  coming  to  rest  more  and  more 
upon  the  detection  of  the  perversions  which  the  actions  of  these  parts  undergo, 
and  of  the  minute  alterations  of  structure  and  composition  which  they  involve. 
.  It  is,  in  fact,  in  the  detection  of  those  first  departures  from  the  normal  actions 
which  frequently  constitute  the  essence  of  a  disease,  and  in  the  determination 
of  the  causes  to  whose  operation  they  are  referable,  that  Medical  Science  is  at 
present  making  the  greatest  progress ;  and  it  would  not  be  difficult  to  show,  that 
this  progress  is  intimately  connected  with  the  advance  of  Physiology.  To  say 
that  it  is  impossible  to  interpret  the  phenomena  of  disease  with  any  probability 
of  correctness,  impossible  to  apply  remedies  with  a  reasonable  expectation  of 
success — impossible,  therefore,  to  practise  the  healing  art  as  it  ought  to  be  prac- 
tised— unless  we  are  acquainted  with  the  normal  or  healthy  action  of  the  system, 
might  seem  a  truism ;  and  yet,  however  self-evident  the  truth  of  the  assertion, 
it  is  very  far  from  having  the  weight  which  it  ought  to  possess.  The  phenomena 
of  Disease  have  been  isolated  from  those  of  Health,  as  if  they  belonged  to  quite 
a  distinct  category,  and  were  dependent  upon  a  set  of  causes  altogether  dissimilar. 
It  has  been  too  much  lost  sight  of,  that  every  diseased  action  is  but  a  perversion, 
by  excess,  by  diminution,  or  by  depravation,  of  some  natural  function ',  and  that 
only  through  an  acquaintance  with  the  latter  can  the  former  be  understood 
(otherwise  than  in  a  merely  empirical  fashion),  either  as  to  its  cause,  its  nature, 
or  its  tendencies.  It  has  been  assumed  by  some  Pathologists,  that  Physiology 
ought  to  furnish  a  set  of  direct  rules  for  the  treatment  of  disease;  and,  as  it 
cannot  rightly  profess  to  furnish  these,  it  has  been  set  down  by  others  as  having 
no  practical  value  whatever.  Whereas  the  real  Medical  Philosopher  rather  looks 
to  Physiology  as  affording  guidance  in  the  pursuit  of  those  rules,  by  furnishing 
a  clue  to  his  interpretation  of  symptoms,  by  pointing  out  the  direction  in  which 
he  may  look  for  remedies,  and  by  letting  in,  here  and  there,  a  beam  of  light 
that  shall  guide  him  through  the  intricacies  of  his  search.  In  fact,  it  is  with 
this  constant  but  unobtrusive  assistance  from  Physiology,  that  the  Pathologist 
advances  in  his  career  of  research ;  and  hence  it  is  just  where  our  Physiological 
knowledge  is  most  precise,  and  its  generalizations  most  comprehensive,  that  our 
Pathological  information  is  most  advanced  and  most  fruitful  in  practical  results. 
It  may  be  taken,  indeed,  as  a  general  fact,  that  those  Arts,  or  collections  of 
rules  for  a  given  purpose,  are  the  most  perfect  in  their  application,  which  are 


40  INTRODUCTION. 

built  upon  the  most  secure  foundation  in  Science.  "It  is  the  office  of  science," 
says  Bacon,  "  to  shorten  the  long  turnings  and  windings  of  experience ;"  and 
in  proportion  as  Medical  Science  becomes  so  perfect,  that  it  can  not  only  say 
what  is,  or  what  happens,  in  the  human  body,  in  the  state  of  health  or  disease, 
but  also  what  will  happen  when  the  conditions  are  altered,  in  that  proportion, 
it  is  evident,  will  it  be  possible  to  frame  rules  or  directions  for  conduct — express- 
ing "do  this/'  "avoid  that" — from  the  practice  of  which  a  certain  result  may 
be  predicted.  And  if,  at  the  present  time,  there  should  be  more  doubt  than 
perhaps  ever  previously  existed  in  the  minds  of  the  Profession  at  large,  with 
regard  to  the  efficacy  of  many  plans  of  medical  treatment,  in  spite  of  the  strong 
testimony  as  to  their  value  which  has  been  traditionally  handed  down,  it  is 
because,  for  the  most  part,  the  confidence  which  has  been  felt  in  them  has 
rested  upon  too  narrow  a  foundation  of  imperfectly- scrutinized  experience,  and 
a  definite  scientific  rationale  has  been  either  found  wanting  altogether,  or,  if  it 
had  a  supposed  existence,  has  been  shown  to  have  been  fallacious.  But,  on  the 
other  hand,  whilst  many  time-honored  traditions  have  thus  been  overthrown, 
new  doctrines  have  been  advanced  with  all  that  assurance  of  value  which  is 
afforded  by  the  clear  and  positive  direction  which  Science  affords ;  and  to  these 
the  intelligent  practitioner  will  attach  himself  as  his  securest  guides,  confident 
that,  even  if  the  practice  they  inculcate  may  not  lead  him  to  the  success  he 
desires,  they  will  not  antagonize  the  efforts  which  Nature  may  be  making  to 
effect  a  cure  in  her  own  way. 

Whilst  it  will  be  the  special  object  of  the  following  Treatise,  therefore,  to  show 
in  what  that  normal  activity  of  the  human  body,  which  we  call  Health,  consists, 
and  to  explain  the  conditions  upon  which  its  continuance  is  dependent,  the 
reader's  attention  will  be  directed  from  time  to  time  to  the  practical  rules  which 
arise  out  of  the  application  of  Physiological  Science  to  the  Art  of  Hygiene ; 
and  in  like  manner,  when  speaking  of  the  most  frequent  of  those  perversions 
of  normal  activity,  in  which  Disease  consists,  some  of  the  most  important  of 
those  principles  of  treatment  will  be  laid  down,  which  constitute  the  application 
of  Pathological  Science  to  the  Art  of  Therapeutics. 

In  proportion  as  the  treatment  of  disease  shall  be  thus  withdrawn  from  the 
domain  of  empiricism,  and  be  founded  on  scientific  principles,  in  that  proportion 
will  the  Medical  Profession  acquire  that  dignified  confidence  in  itself,  which 
shall  keep  it  steady  to  its  high  and  noble  aims ;  and  will  attain  that  general  esti- 
mation, which  will  be  freely  accorded  to  its  enlightened  and  disinterested  pursuit 
of  them. 


CHAPTER    I. 

OF   THE  DISTINCTIVE   CHARACTERISTICS   OP   MAN. 

1.  BY  Cuvier  and  nearly  all  modern  Zoologists,  the  various  races  of  Mankind 
are  included  under  one  genus,  Homo;  and  this  genus  takes  rank,  in  the  classi- 
fication of  Mammalia,  as  a  distinct  order,  BIMANA,  of  which  it  is  the  sole 
representative.  Of  all  the  characters  which  distinguish  Man  from  the  inferior 
Mammalia,  the  possession  of  two  hands  is  doubtless  the  most  easily  recognized, 
and  at  the  same  time,  the  most  intimately  related  to  the  general  organization  of 
the  body;  and  there  is  none,  therefore,  which  could  be  more  appropriately 
selected  as  the  basis  of  a  distinctive  designation  of  this  order.  At  first  sight,  it 
might  be  considered  that  the  possession  of  only  two  hands,  whilst  Apes  and 
Monkeys  and  their  allies  are  designated  as  possessing  four,  is  a  character  of  in- 
feriority; but  such  is  not  really  the  case;  for  none  of  these  four  hands  are 
adapted  to  the  variety  of  actions  of  which  those  of  man  are  capable,  and  they 
are  all  in  some  degree  required  for  support;  so  that  whilst  in  the  higher  forms 
of  the  Quadrumanous  order,  the  extremities  present  a  certain  approximation  in 
structure  to  those  of  Man,  in  the  lower  they  gradually  assimilate  to  the  ordi- 
nary quadrupedal  type.  "That,"  says  Cuvier,  "which  constitutes  the  handy 
properly  so  called,  is  the  faculty  of  opposing  the  thumb  to  the  other  fingers,  so 
as  to  seize  upon  the  most  minute  objects;  a  faculty  which  is  carried  to  its  highest 
degree  of  perfection  in  Man,  in  whom  the  whole  anterior  extremity  is  free,  and 
can  be  employed  in  prehension."  The  peculiar  prehensile  power  possessed  by 
Man  is  chiefly  dependent  upon  the  size  and  power  of  the  thumb;  which  is  more 
developed  in  Man,  than  it  is  in  the  highest  apes.  The  thumb  of  the  human 
hand  can  be  brought  into  exact  opposition  to  the  extremities  of  all  the  fingers, 
whether  singly  or  in  combination;  whilst  in  those  Quadrumaiia  which  most 
nearly  approach  Man,  the  thumb  is  so  short,  and  the  fingers  so  much  elongated, 
that  their  tips  can  scarcely  be  brought  into  opposition;  and  the  thumb  and 
fingers  are  so  weak,  that  they  can  never  be  opposed  to  each  other  with  any  de- 
gree of  force.  Hence,  although  admirably  adapted  for  clinging  round  bodies 
of  a  certain  size,  such  as  the  small  branches  of  trees,  &c.,  the  extremities  of  the 
Qua'drumana  can  neither  seize  very  minute  objects  with  such  precision,  nor  sup- 
port large  ones  with  such  firmness,  as  are  essential  to  the  dexterous  performance 
of  a  variety  of  operations,  for  which  the  hand  of  Man  is  admirably  adapted. 
There  is  much  truth,  then,  in  Sir  C.  Bell's  remark,  that  "we  ought  to  define 
the  hand  as  belonging  exclusively  to  man."  There  is  in  him,  what  we  observe 
in  none  of  the  Mammalia  which  approach  him  in  other  respects,  a  complete  dis- 
tinction in  the  functional  character  of  the  anterior  and  posterior  extremities; 
the  former  being  adapted  for  prehension  alone,  and  the  latter  for  support  and 
progression  alone ;  and  thus  each  function  is  performed  in  a  much  higher  degree 
of  perfection,  than  it  can  be  when  two  such  opposite  purposes  have  to  be  united. 
For  not  only  is  the  hand  of  Man  a  much  more  perfect  prehensile  instrument 
than  that  of  the  Orang  or  Chimpanzee,  but  his  foot  is  a  much  more  perfect 
organ  of  support  and  progression  than  theirs,  being  adapted  to  maintain  his 
body  in  an  erect  position,  alike  during  rest  and  whilst  in  motion — an  attitude 
which  even  the  most  anthropoid  apes  can  only  sustain  for  a  short  time,  and  with 


42  HUMAN   PHYSIOLOGY. 

an  obvious  effort.  The  arm  of  the  higher  apes  has  as  wide  a  range  of  motion 
as  that  of  Man,  so  far  as' its  articulation  is  concerned;  but  it  is  only  when  the 
animal  is  in  the  erect  attitude,  that  the  limb  can  have  free  play.  Thus  the 
structure  of  the  whole  frame  must  be  conformable  to  that  of  the  hand,  in  the 
way  that  we  find  it  to  be  in  Man,  in  order  that  this  organ  may  be  advantage- 
ously applied  to  the  purposes  which  it  is  adapted  to  perform.  But  it  cannot  be 
said  with  truth  (as  some  have  maintained)  that  Man  owes  his  superiority  to  his 
hand  alone ;  for  without  the  mind  by  which  it  is  directed,  and  the  senses  by 
which  its  operations  are  guided,  it  would  be  a  comparatively  valueless  instru- 
ment. Man's  elevated  position  is  due  to  the  superiority  of  his  mind  and  of  its 
material  instruments  conjointly;  for  if  destitute  of  either,  the  human  race  must 
be  speedily  extinguished  altogether,  or  reduced  to  a  very  subordinate  grade  of 
existence. 

2.  The  next  series  of  characters  to  be  considered,  are  those  by  which  Man  is 
adapted  to  the  erect  attitude. — On  examining  his  cranium,  we  remark  that  the 
occipital  condyles  are  so  placed,  that  a  perpendicular  dropped  from  the  centre 
of  gravity  of  the  head  would  nearly  fall  between  them,  so  as  to  be  within  the 
base  on  which  it  rests  upon  the  spinal  column.  The  foramen  magnum  is  not 
placed  in  the  centre  of  the  base  of  the  skull,  but  just  behind  it;  so  that  the 
greater  specific  gravity  of  the  posterior  part  of  the  head,  which  is  entirely  filled 
with  solid  matter,  is  compensated  by  the  greater  length  of  the  anterior  part, 
which  contains  many  cavities.  There  is,  indeed,  a  little  over-compensation, 
which  gives  a  slight  preponderance  to  the  front  of  the  head,  so  that  it  drops 
forwards  and  downwards,  when  all  the  muscles  are  relaxed ;  but  the  muscles 
which  are  attached  to  the  back  of  the  head  are  far  larger  and  more  numerous 
than  those  in  front  of  the  condyles,  so  that  they  are  evidently  intended  to 
counteract  this  disposition ;  and  we  find,  accordingly,  that  we  can  keep  up  the 
head  for  the  whole  day,  with  so  slight  and  involuntary  an  effort,  that  no  fatigue 
is  produced  by  it.  Moreover,  the  plane  of  the  foramen  magnum,  and  the  sur- 
faces of  the  condyles,  have  a  nearly  horizontal  direction  when  the  head  is  up- 
right; and  thus  the  weight  of  the  skull  is  laid  vertically  upon  the  top  of  the 
vertebral  column.  If  these  arrangements  be  compared  with  those  which  pre- 
vail in  other  Mammalia,  it  will  be  found  that  the  foramen  and  condyles  are 
placed  in  the  latter  much  nearer  the  back  of  the  head,  and  that  their  plane  is 
more  oblique.  Thus,  whilst  the  foramen  magnum  is  situated,  in  Man,  just 
behind  the  centre  of  the  base  of  the  skull,  it  is  found,  in  the  Chimpanzee  and 
Orang  Outan,  to  occupy  the  middle  of  the  posterior  third  (Fig.  1);  and,  as  we 
descend  through  the  scale  of  Mammalia,  we  observe  that  it  gradually  approaches 
the  back  of  the  skull,  and  at  last  comes  nearly  into  the  line  of  its  longest  dia- 
meter, as  we  see  in  the  Horse.  Again,  in  all  Mammalia  except  Man,  the  plane 
of  the  condyles  is  oblique,  so  that,  even  if  the  head  were  equally  balanced  upon 
them,  the  force  of  gravity  would  tend  to  carry  it  forwards  and  downwards :  in 
Man,  the  angle  which  they  make  with  the  horizon  is  very  small;  in  the  Orang 
Outan,  it  is  as  much  as  37°;  and  in  the  Horse,  their  plane  is  vertical,  making 
the  angle  90°.  If,  therefore,  the  natural  posture  of  Man  were  horizontal,  the 
plane  of  his  condyles  would  be  brought,  like  that  of  the  Horse,  into  the  verti- 
cal position ;  and  the  head,  instead  of  being  nearly  balanced  on  the  summit  of 
the  vertebral  column,  would  hang  at  the  end  of  the  neck,  so  that  its  whole 
weight  would  have  to  be  supported  by  some  external  and  constantly-acting 
power.  But  for  this,  there  is  neither  in  the  skeleton,  the  ligamentous  appara- 
tus, nor  the  muscular  system  of  Man,  any  adequate  provision;  so  that  in  any 
other  than  the  vertical  position,  his  head,  which  is  relatively  heavier  than  that 
of  most  Mammalia,  would  be  supported  with  more  difficulty  and  effort  than  it 
is  in  any  other  animal. 

3.  The  position  of  the  face  immediately  beneath  the  brain,  so  that  its  front 


DISTINCTIVE   CHARACTERISTICS   OF   MAN. 


43 


is  nearly  in  the  same  plane  as  the  forehead,  is  peculiarly  characteristic  of  Man  ; 
for  the  crania  of  the  Chimpanzee  and  Orang,  which  approach  nearest  to  that  of 
Man,  are  entirely  posterior  to,  and  not  above,  the  face.  It  should  be  remarked 

Fig.  1. 


View  of  the  base  of  the  skull  of  Man,  compared  with  that  of  the  Orang  Outan. 

that,  in  the  young  Ape,  there  is  a  much  greater  resemblance  to  Man  in  this 
respect,  than  there  is  in  the  adult;  for  it  is  at  the  time  of  the  second  dentition, 
that  the  muzzle  of  the  Ape  acquires  its  peculiar  elongation,  and  consequent 
projection  in  front  of  the  forehead  (Fig.  1);  and  the  whole  cast  of  the  features 
is  altered  at  the  same  time,  so  that  it  approaches  much  more  to  that  of  the  lower 
Quadrumana,  than  would  be  supposed  from  observation  of  the  young  animal 
only.1  This  increased  projection  of  the  muzzle,  taken  in  connection  with  the 
obliquity  of  the  condyles,  is  another  evidence  of  want  of  perfect  adaptation  to 
the  erect  posture ;  whilst  the  absence  of  prominence  in  the  face  of  Man  shows 
that  none  but  the  erect  position  can  be  natural  to  him.  For  supposing  that, 
with  a  head  formed  and  situated  as  at  present,  he  were  to  move  on  all-fours,  his 
face  would  be  brought  into  a  plane  parallel  with  the  ground ;  so  that  as  painful 
an  effort  would  be  required  to  examine  with  the  eyes  an  object  placed  in  front 
of  the  body,  as  is  now  necessary  to  keep  the  eyes  fixed  on  the  zenith;  the  nose 
would  then  be  incapacitated  for  receiving  any  other  odorous  emanations,  than 
those  proceeding  from  the  earth  or  from  the  body  itself;  and  the  mouth  could 
not  touch  the  ground,  without  bringing  the  forehead  and  chin  also  into  contact 
with  it.  The  oblique  position  of  the  condyles  in  the  Quadrumana  enables  them, 
without  much  difficulty,  to  adapt  the  inclination  of  their  heads  to  the  horizontal 
or  to  the  erect  posture ;  but  the  natural  position,  in  the  highest  among  them,  is 
unquestionably  one  in  which  the  spinal  column  is  inclined,  the  body  being 
partially  thrown  forwards,  so  as  to  rest  upon  the  anterior  extremities ;  and  in  this 
position,  the  face  is  directed  forwards  without  any  effort,  owing  to  the  mode  in 
which  the  head  is  obliquely  articulated  with  the  spine. 

4.  The  vertebral  column  in  Man,  although  not  absolutely  straight,  has  its 
curves  so  arranged,  that,  when  the  body  is  in  an  erect  posture,  a  vertical  line 
from  its  summit  would  Ml  exactly  on  the  centre  of  its  base.  It  increases  con- 
siderably in  size  in  the  lumbar  region,  so  as  to  be  altogether  somewhat  pyramidal 

1  None  but  young  specimens  of  the  Chimpanzee  and  Orang  Outan  have  ever  been 
brought  alive  to  this  country ;  and  they  have  never  long  survived  the  period  of  their  second 
dentition. 


44  HUMAN   PHYSIOLOGY. 

in  form.  The  lumbar  portion,  in  the  Chimpanzee  and  Orang,  is  not  of  the  same 
proportional  strength;  and  contains  but  four  vertebrae,  instead  of  five.  The 
processes  for  the  attachment  of  the  dorso-spinal  muscles  to  this  part,  are  pecu- 
liarly large  and  strong  in  Man;  and  this  arrangement  is  obviously  adapted  to 
overcome  the  tendency,  which  the  weight  of  the  viscera  in  front  of  the  column 
would  have,  to  draw  it  forwards  and  downwards.  On  the  other  hand,  the 
spinous  processes  of  the  cervical  and  dorsal  vertebrae,  which  are  in  other  Mam- 
malia large  and  strong,  for  the  attachment  of  the  ligaments  and  muscles  that 
support  the  head,  have  comparatively  little  prominence  in  Man,  his  head  being 
nearly  balanced  on  the  top  of  the  column. — The  base  of  the  human  vertebral 
column  is  placed  on  a  sacrum  of  greater  proportional  breadth,  than  that  of  any 
other  animal;  this  sacrum  is  fixed  between  two  widely-expanded  ilia;  and  the 
whole  pelvis  is  thus  peculiarly  broad.  In  this  manner,  the  femoral  articulations 
are  thrown  very  far  apart,  so  as  to  give  a  wide  basis  of  support ;  and  by  the 
oblique  direction  of  the  pelvis,  the  weight  of  the  body  is  transmitted  almost 
vertically  from  the  top  of  the  sacrum  to  the  upper  part  of  the  thigh-bones. 
The  pelvis  of  the  anthropoid  Apes  is  very  differently  constructed;  as  will  be  seen 
in  the  adjoining  cut  (Fig.  2),  in  which  the  skeleton  of  the  Orang  is  placed  in 
proximity  with  that  of  Man.  It  is  much  larger  and  narrower;  its  alas  extend 
upwards  rather  than  outwards,  so  that  the  space  between  the  lowest  ribs  and 
the  crest  of  the  iliac  bones  is  much  less  than  in  Man;  their  surfaces  are  nearly 
parallel  to  that  of  the  sacrum,  which  is  itself  longer  and  narrower ;  and  the 
axis  of  the  pelvis  is  nearly  parallel  with  that  of  the  vertebral  column.  The 
position  of  the  human  femur,  in  which  its  head  is  most  securely  retained  in  its 
deep  aeetabulum,  is  that  which  it  has,  when  supporting  the  body  in  the  erect 
attitude;  in  the  Chimpanzee  and  Orang,  its  analogous  position  is  an  obliquo 
angle  to  the  long  axis  of  the  pelvis,  so  that  the  body  leans  forwards  in  front  of 
it;  in  many  Mammalia,  as  in  the  Elephant,  it  forms  nearly  a  right  angle  with 
the  vertebral  column;  and  in  several  others,  as  the  Horse,  Ox,  &c.;  the  angle 
which  it  makes  with  the  axis  of  the  pelvis  and  vertebral  column  is  acute.  In 
this  respect,  then,  the  skeleton  of  Man  presents  an  adaptation  to  the  erect  pos- 
ture, which  is  exhibited  by  that  of  no  other  Mammal. 

5.  The  lower  extremities  of  Man  are  remarkable  for  their  length  ;  which  is 
proportionably  greater  than  that  which  we  find  in  any  other  Mammalia,  except 
the  Kangaroo  tribe.  The  chief  difference  in  their  proportional  length,  between 
Man  and  the  semi-erect  Apes,  is  seen  in  the  thigh ;  and .  it  is  from  the  relative 
length  of  this  part  in  him,  as  well  as  from  the  comparative  shortness  of  his  an- 
terior extremities,  that  his  hands  only  reach  the  middle  of  his  thighs,  whilst  in 
the  Chimpanzee  they  hang  on  a  level  with  the  knees,  and  in  the  Orang  they 
descend  to  the  ankles.  The  Human  femur  is  distinguished  by  its  form  and 
position,  as  well  as  by  its  length.  The  obliquity  and  length  of  its  neck  still 
further  increase  the  breadth  of  the  hips ;  whilst  they  cause  the  lower  extremities 
of  the  femora  to  be  somewhat  obliquely  directed  towards  each  other,  so  that  the 
knees  are  brought  more  into  the  line  of  the  axis  of  the  body.  This  arrangement 
is  obviously  of  great  use  in  facilitating  the  purely  biped  progression  of  Man,  in 
which  the  entire  weight  of  the  body  has  to  be  alternately  supported  on  each 
limb ;  for  if  the  knees  had  been  kept  further  apart,  the  whole  body  must  have 
been  swung  from  side  to  side  at  each  step,  so  as  to  bring  the  centre  of  gravity 
over  the  top  of  each  tibia ;  as  is  seen,  to  a  certain  extent,  in  the  female  sex, 
whose  walk,  owing  to  the  greater  breadth  of  the  pelvis  and  the  separation  be- 
tween the  knees,  is  less  steady  than  that  of  the  male.  There  is  a  very  marked 
contrast  between  the  knee-joint  of  Man,  and  that  even  of  the  highest  Apes.  In 
the  former,  the  opposed  extremities  of  the  femur  and  the  tibia  are  expanded,  so 
as  to  present  a  very  broad  articulating  surface ;  and  the  internal  condyle  of  the 
femur  being  the  longer  of  the  two,  they  are  in  the  same  horizontal  plane  in  the 


DISTINCTIVE   CHARACTERISTICS   OF   MAN 


45 


Fig.  2. 


Comparative  view  of  the  Skeleton  of  Man  and  that  of  the  Orang  Outan. 


46  HUMAN  PHYSIOLOGY. 

usual  oblique  position  of  that  bone ;  so  that  by  this  arrangement,  the  whole 
weight-  of  the  body,  in  its  erect  posture,  falls  vertically  on  the  top  of  the  tibia, 
when  the  joint  is  in  the  firmest  position  in  which  it  can  be  placed.  The  knee- 
joint  of  the  Orang,  on  the  other  hand,  is  comparatively  deficient  in  extent  of 
articulating  surface  ;  and  its  whole  conformation  indicates  that  it  is  not  intended 
to  serve  as  more  than  a  partial  support.  The  Human  foot  is,  in  proportion  to 
the  size  of  the  whole  body,  larger,  broader,  and  stronger,  than  that  of  any  other 
Mammal  save  the  Kangaroo.  Its  plane  is  directed  at  right  angles  to  that  of  the 
leg ;  and  its  sole  is  concave,  so  that  the  weight  of  the  body  falls  on  the  summit 
of  an  arch,  of  which  the  os  calcis  and  the  metatarsal  bones  form  the  two  points 
of  support.  This  arched  form  of  the  foot,  and  the  natural  contact  of  the  os 
calcis  with  the  ground,  are  peculiar  to  Man  alone.  All  the  Apes  have  the  os 
calcis  small,  straight,  and  more  or  less  raised  from  the  ground  ;  which  they 
touch,  when  standing  erect,  with  the  outer  side  only  of  the  foot :  whilst  in 
animals  more  remote  from  Man,  the  os  calcis  is  brought  still  more  into  the  line 
of  the  tibia ;  and  the  foot  being  more  elongated  and  narrowed,  only  the  extremi- 
ties of  the  toes  come  in  contact  with  the  ground.  Hence  Man  is  the  only  species 
of  Mammal  which  can  stand  upon  one  leg.  All  the  points  in  which  the  feet  of 
the  anthropoid  Apes  differ  from  his,  are  such  as  assimilate  them  to  the  manual 
type  of  conformation,  and  enable  them  to  serve  as  more  efficient  prehensile 
organs ;  whilst  they  diminish  their  capacity  to  sustain  the  weight  of  the  body, 
when  it  simply  rests  upon  them. 

6.  There  is  a  considerable  difference  in  the  form  of  the  trunk,  between  Man 
and  most  other  Mammalia ;  for  his  thorax  is  expanded  laterally,  and  flattened 
in  front,  so  as  to  prevent  the  centre  of  gravity  from  being  carried  too  far  for- 
wards ;  and  his  sternum  is  short  and  broad.     Between  the  bony  walls  of  the 
thorax  and  the  margin  of  the  pelvis,  a  considerable  space  intervenes,  which  is 
occupied  solely  by  muscles  and  tegmnentary  membranes ;  and  these  would  be 
quite  insufficient  to  sustain  the  weight  of  the  viscera,  if  the  habitual  position  of 
the  trunk  had  been  horizontal.     In  these  particulars,  however,  the  most  anthro- 
poid Apes  agree  more  or  less  completely  with  Man. 

7.  Returning  now  to  the  skull  for  a  more  minute  examination,  we  observe 
that  the  cranium  of  Man  is  distinguished  from  that  of  the  anthropoid  Apes,  not 
merely  by  its  great  capacity,  but  also  by  its  smoothness ;  its  surface  being 
almost  entirely  deficient  in  those  ridges  for  the  attachment  of  muscles,  which 
are  remarkably  strong  both  in  the  Chimpanzee  and  Orang,  and  which  impart 
to  its  configuration  somewhat  of  a  carnivorous  character.    This  aspect  is  strength- 
ened by  the  great  depth  of  the  temporal  fossa,  and  by  the  extent  and  strength 
of  the  zygomatic  arch;  features  that  are  most  remarkably  developed  in  the 
Troglodytes  gorilla,  a  newly-discovered  species  of  Chimpanzee,  which  is  regarded 
by  Prof.  Owen  as  presenting  on  the  whole  the  nearest  approach  to  the  human 
type.     Moreover,  the  jaws  in  even  the  most  degraded  races  of  Man  project  far 
less  from  the  general  plane  of  the  face,  than  they  do  in  the  Apes  ;  and  his  teeth 
are  arranged  in  a  continuous  series,  without  any  hiatus  or  any  considerable  dif- 
ference in  length,  whilst  all  the  Apes,  in  their  adult  state  at  least,  are  furnished 
with  canine  teeth  of  extraordinary  length,  between  the  sockets  of  which  and 
those  of  the  adjoining  teeth  (in  front  in  the  upper  jaw,  and  behind  in  the  lower), 
there  is  a  vacant  space  or  diastenia.     Even  in  the  most  prognathous  Human 
skulls,  moreover,  the  incisors  meet  each  other  much  more  nearly  in  the  same 
axis  than  they  do  in  the  anthropoid  Apes,  in  which  they  form  an  angle  with 
each  other  that  is  not  nearly  so  divergent.     The  fusion  of  the  intermaxillary  or 
premaxillary  bones  with  the  superior  maxillary,  at  an  early  period  of  foetal  life, 
is  a  remarkable  character  of  the  Human  cranium,  as  distinguishing  it  from  that 
of  the  Apes,  in  which  the  intermaxillary  bones  remain  separate  to  a  much  later 
period;  sometimes  differing  also,  in  a  very  marked  degree,  in  size  and  shape. 


DISTINCTIVE   CHARACTERISTICS   OF   MAN.  47 

Thus  in  the  Troglodytes  gorilla,  these  bones  are  not  only  remarkable  for  their 
prominence,  but  also  for  their  upward  extension  round  the  nostrils,  so  that  they 
completely  exclude  the  maxillary  bones  from  their  borders,  and  form  the  bases 
of  support  for  the  nasal  bones ;  and  although  they  coalesce  with  the  maxillaries 
at  and  near  the  alveolar  portion,  they  remain  separate  elsewhere.  The  lower 
jaw  of  Man  is  remarkable  for  that  prominence  at  its  symphysis,  which  forms 
the  chin ;  and  although  this,  also,  is  least  developed  in  the  most  prognathous 
human  crania,  yet  it  is  never  so  deficient  as  it  is  in  the  lower  jaw  of  the  Chim- 
panzee and  Orang. — It  is  curious  to  observe  that  the  skulls  of  the  young  of 
Man  and  of  the  anthropoid  Apes  resemble  one  another  much  more  than  do  those 
of  the  adults  ;  each  tending  to  diverge,  in  its  advance  towards  full  development, 
from  a  type  which  seemed  almost  similar  in  both.  It  is  only  after  their  second 
dentition,  that  the  anthropoid  Apes  present  those  cranial  characters  which  pecu- 
liarly tend  to  degrade  them  towards  the  truly  quadrupedal  type ;  and  in  the 
Human  subject  we  see  that  in  the  advance  from  childhood  to  adult  age,  there 
is  a  progressive  enlargement  of  the  face,  in  proportion  to  the'  capacity  of  the 
cranial  cavity.1 

8.  The  great  size  of  the  cranial  portion  of  the  skull  in  Man,  as  compared 
with  the  facial,  produces  a  marked  difference  between  his  facial  angle,  and  that 
of  even  the  highest  Quadrumana.     According  to  Camper,  who  first  applied  this 
method  of  measurement,  the  facial  angle  of  the  average  of  European  skulls  is 
80°,  whilst  in  the  ideal  heads  of  the  Grecian  gods  it  is  increased  to  90° ;  on 
the  other  hand,  in  the  skull  of  a  Kalmuck  he  found  it  to  be  75° ;  and  in  that 
of  a  Negro  only  70° ;  and  applying  the  same  system  of  measurement  to  the 
skulls  of  Apes,  he  found  them  to  range  from  64°  to  60°.     But  these  last  mea- 
surements were  all  taken  from  young  skulls,  in  which  the  forward  extension  of 
the  jaws,  which  takes  place  on  the  second  dentition,  had  not  yet  occurred.     In 
the  adult  Chimpanzee,  as  we  learn  from   the   measurements  of  Prof.  Owen, 
the  facial  angle  is  no  more  than  35°,  and  in  the  adult  Orang  only  30° ;  so  that 
instead  of  the  Negro  being  nearer  to  the  Ape  than  to  the  European,  as  Camper's 
estimate  would  make  him,  the  interval  between  the  most  degraded  Human  races 
and  the  most  elevated  Quadrumana  is  vastly  greater  than  between  the  highest 
and  the  lowest  forms  of  humanity.     It  must  be  borne  in  mind  that  the  facial 
angle  is  so  much  affected  by  the  degree  of  prominence  of  the  jaws,  that  it  can 
never  afford  any  certain  information  concerning  the  elevation  of  the  forehead 
and  the  capacity  of  the  cranium  ;  all  that  it  can  in  any  degree  serve  to  indicate, 
being  the  relative  proportion  between  the  facial  and  the  cranial  parts  of  the 
skull. 

9.  The  most  characteristic  peculiarity  of  the  Human  Myology,  is  the  great 
development  of  those  muscles  of  the  trunk  and  limbs  which  contribute  to  the 
maintenance  of  the  erect  posture.     Thus,  the  gastrocnemii,  and  the  other  mus- 
cles which  tend  to  keep  the  leg  erect  upon  the  foot,  form  a  much  more  promi- 
nent "  calf  than  is  seen  either  in  the  most  anthropoid  Apes,  or  in  any  other 
animal.     So,  again,  the  extensors  of  the  leg  upon  the  thigh  are  much  more 
powerful  than  the  flexors;  a  character  which  is  peculiar  to  man.     The  glutsei, 
by  which  the  pelvis  is  kept  erect  upon  the  thigh,  are  of  far  greater  size  than  is 
elsewhere   seen.     The  superior  power  of  the  muscles  tending  to  draw  the  head 
and  spine  backwards,  has  been  already  referred  to.     Among  the  differences  in 
the  attachment  of  individual  muscles,  it  may  be  noticed  that  the  flexor  longus 
pollicis  pedis  proceeds  in   Man  to  the  great  toe  alone,  on  which  the  weight  of 
the  body  is  often  supported  j  whilst  it  is  attached  in  the  Chimpanzee  and  Orang 

1  See  Prof.  Owen's  Papers  on  the  Anatomy  of  the  Orang  and  Chimpanzee,  in  the  "  Zoo- 
logical Transactions,"  vols.  i.  and  iii. ;  and  Prof.  Vrolik,  in  the  Art.  Quadrumana,  in  the 
"Cyclopaedia  of  Anatomy  and  Physiology,"  vol.  iv. 


48  HUMAN   PHYSIOLOGY. 

to  the  three  middle  toes  also.     The  latissimus  dorsi  is  destitute  in  Man  of  that 
prolongation  attached  to  the  olecranon,  which  is  found  in  the  lower  Mammalia, 
and  which  exists  even  in  the  Chimpanzee,  probably  giving  assistance  in  its  climb- 
ing operations.     The  larger  size  of  the  muscles  of  the  thumb  is,  as  might  be  ex- 
rted,  a  characteristic  of  the  hand  of  Man ;  although  the  number  of  muscles 
which  that  digit  is  moved  is  the  same  in  the  Chimpanzee  as  in  the  Human 
subject.     The  existence  of  the  extensor  digiti  indicis,  however,  as  a  distinct 
muscle,  is  peculiar  to  Man. 

10.  The  Visceral  apparatus  of  Man  presents  very  few  characteristic  pecu- 
liarities, by  which  it  can  be  distinguished  from  that  of  the  higher  Quadrumana ; 
among  the  most  remarkable  is  the  absence  of  the  laryngeal  pouches,  which  exist 
even  in  the  Chimpanzee  and  Orang  Outan,  as  dilatations  of  the  laryngeal  ven- 
tricles.— Of  the  anatomy  of  the  last-named  animals  in  their  adult  condition, 
however,  we  know  as  yet  too  little  to  enable  its  conformity  to  that  of  Man  to  be 
confidently  pronounced  upon. 

11.  The  Brain  of  Man  does  not  differ  so  much  in  conformation  from  that  of 
the  Chimpanzee  and  Orang,  as  the  superiority  of  his  mental  endowments  might 
have  led  us  to  anticipate.     The  following  are  the  principal  differences  which  it 
seems  to  present :  1.  The  mass  of  the  entire  brain  is  considerably  larger  in 
proportion  to  that  of  the  body,  and  in  proportion  also  to  the  diameter  of  the 
nerves  which  are  connected  with  it. — 2.  In  the  external  configuration  of  the 
Cerebrum,  we  notice  that  the  posterior  lobes  are  more  developed,  so  as  to  pro- 
ject further  beyond  the  Cerebellum  than  they  do  in  any  of  the  Quadrumana ; 
the  convolutions  are  more  numerous,  and  the  sulci  are  deeper. — 3.  On  examin- 
ing the  internal  structure,  it  is  found  that  the  peripheral  layer  of  gray  matter 
is  thicker,  the  corpus  callosum  extends  further  backwards,  and  the  posterior 
cornua  of  the  lateral  ventricles  are  relatively  longer  and  larger  than  they  are  in 
any  Quadrumana.— 4.  The  Cerebellum,  also,  is  proportionally  larger. 

12.  The  small  size  of  the  face  of  Man,  compared  with  that  of  the  cranium,  is 
an  indication  that  in  him  the  senses  are  subordinate  to  the  intelligence.     Accord- 
ingly we  find  that  while  he  is  surpassed  by  many  of  the  lower  animals  in  acuteness 
of  sensibility  to  light,  sound,  &c.  he  stands  pre-eminent  in  the  power  of  comparing 
and  judging  of  his  sensations,  and  of  drawing  conclusions  from  them  as  to  their  ob- 
jective sources.    Moreover,  although  none  of  his  senses  are  very  acute  in  his  natu- 
ral state  they  are  all  moderately  so,  and  they  are  capable  of  being  wonderfully 
improved  by  practice,  when  circumstances  strongly  call  for  their  exercise.     This 
seems  especially  the  case  with  the  tactile  sense,  of  which  Man  can  make  greater  use 
than  any  other  animal,  in  consequence  of  the  entire  freedom  of  his  anterior  extre- 
mities ;  although  there  are  many  which  surpass  him  in  their  power  of  appreciating 
certain  classes  of  tactile  impressions. — So  again,  Man's  nervo-muscular  power  is 
inferior  to  that  of  most  other  animals  of  his  size ;   the  full  grown  Orang,  for 
example,  surpasses  him  both  in  strength  and  agility ;  and  the  larger  Chimpan- 
zee, according  to  the  statements  of  the  Negroes  who  have  encountered  it,  is  far 
more  than  a  match  for  any  single  man,  and  is  almost  certain  to  destroy  any 
human  opponent  once  within  his  grasp.     The  absence  of  any  natural  weapons 
of  offence,  and  of  direct  means  of,  defence,  are  remarkable  characteristics  of 
Man,  and  distinguish  him  not  only  from  the  lower  Mammalia,  but  also  from  the 
most  anthropoid  Apes  j  in  which  it  is  obvious  (both  from  their  habits  and  gene- 
ral organization)  that  the  enormous  canines  have  no  relation  to  a  carnivorous 
regimen,  but  are  instruments  of  warfare.     On  those  animals  to  which  Nature 
has  denied  weapons  of  attack,  she  has  bestowed  the  means  either  of  passive 
defence,  of  concealment,  or  of  flight ;  in  each  of  which  Man  is  deficient.     Yet, 
by  his  superior  reason,  he  has  not  only  been  enabled  to  resist  the  attacks  of 
other  animals,  but  even  to  bring  them  into  subjection  to  himself.     His  intellect 
can  scarcely  suggest  the  mechanism  which  his  hands  cannot  frame ;  and  he  has 


DISTINCTIVE   CHARACTERISTICS    OF    MAN.  49 

devised  and  constructed  arms  more  powerful  than  those  which  any  creature 
wields,  and  defences  so  secure  as  to  defy  the  assaults  of  all  but  his  fellow-men. 

13.  Man  is  further  remarkable  for  his  power  of  adaptation  to  varieties  in  ex- 
ternal condition,  which  renders  him  to  a  great  extent  independent  of  them.  He 
is  capable  of  sustaining  the  highest  as  well  as  the  lowest  extremes  of  tempera- 
ture, and  of  atmospheric  pressure.     In  the  former  of  these  particulars,  he  is 
strikingly  contrasted  with  the  anthropoid  Apes;  the  Chimpanzees  being  restricted 
to  the  hottest  parts  of  Africa,  and  the  Orang  Outan  to  the  tropical  portions  of 
the  Indian  Archipelago;  and  neither  of  these  Animals  being  capable  of  living 
in  temperate  climates  without  the  assistance  of  artificial  heat,  even  with  the  aid 
of  which  they  have  not  hitherto  survived  their  second  dentition.     So,  again, 
although  Man's  diet  seems  naturally  of  a  mixed  character,  he  can  support  him- 
self in  health  and  strength,  either  on  an  exclusively  vegetable  diet,  or,  under 
particular  circumstances,  on  an  almost  exclusively  animal  regimen. 

14.  The   slow  growth  of  Man,  and  the  length  of  time  during  which  he 
remains  in  a  state  of  dependence,  are  peculiarities  that  remarkably  distinguish 
him  from  all  other  animals.     He  is  unable  to  obtain  his  own  food,  during  at  least 
the  first  three  years  of  his  life ;  and  he  does  not  attain  to  his  full  bodily  stature 
and  mental  capacity,  until  he  is  more  than  twenty  years  of  age.     This  retarda- 
tion of  the  developmental  process  seems  to  have  reference  to  the  high  grade 
which  it  is  ultimately  to  attain;  for  everywhere,  throughout  the  Organized 
Creation,  do  we  observe  that  the  most  elevated  forms  are  those  which  go  through 
the  longest  preparatory  stages,  and  of  which  the  evolution  is  most  dependent 
upon  the  assistance  afforded  by  the  parental  organism  during  its  earlier  periods. 
The  peculiar  prolongation  of  this  state  of  dependence  in  the  Human  species  has 
a  most  important  and  evident  effect  upon  the  social  condition  of  the  race ;  being, 
in  fact,  the  chief  source  of  family  ties,  and  affording  the  opportunity  for  the 
education  which  transmits  to  the  rising  generation  tlie  influence  of  the  intel- 
lectual culture  and  moral  training  of  the  past. 

15.  Still,  however  widely  Man  may  be  distinguished  from  other  animals  by 
these  and  other  particulars  of  his  structure  and  economy,  he  is  yet  more  dis- 
tinguished by  those  mental  endowments,  and  by  the  habitudes  of  life  and  action 
thence  resulting,  which  must  be  regarded  as  the  essential  characteristics  of 
humanity.     It  is  in  adapting  himself  to  the  conditions  of  his  existence,  in  pro- 
viding himself  with  food,  shelter,  weapons  of  attack  and  defence,  &c.,  that 
Man's  intellectual  powers  are  first  called  into  active  operation;  and  when  thus 
aroused,  their  development  has  no  assignable  limit.     The  Will,  guided  by  the 
intelligence,  and  acted  on  by  the  desires  and  emotions,  takes  the  place  in  Man 
of  the  Instinctive  propensities  which  are  the  usual  springs  of  action  in  the 
lower  animals ;  and  although  among  the  most  elevated  of  these,  the  intelligent 
will  is  called  into  exercise  to  a  certain  extent,  yet  it  never  acquires  among  them 
the  dominance  which  it  possesses  in  Man,  and  the  character  never  rises  beyond 
that  of  the  child.     In  fact,  the  correspondence  between  the  psychical  endow- 
ments of  the  Chimpanzee,  and  those  of  the  Human  infant  before  it  begins  to 
speak,  is  very  close.     The  capacity  for  intellectual  progress  is  a  most  remark- 
able peculiarity  of  Man's  psychical  nature.     The  instinctive  habits  of  the  lower 
animals  are  limited,  are  peculiar  to  each  species,  and  have  immediate  reference 
to  their  bodily  wants.     Where  a  particular  adaptation  of  means  to  ends,  of 
actions  to  circumstances,  is  made  by  an  individual  (as  is  frequently  the  case, 
when  some  amount  of  intelligence  or  rationality  exists),  the  rest  do  not  seem 
to  profit  by  that  experience ;  so  that,  although  the  instincts  of  particular  animals 
may  be  modified  by  the  training  of  Man,  or  by  the  education  of  circumstances, 
so  as  to  show  themselves  after  a  few  generations  under  new  forms,  no  elevation 
in  intelligence  appears  ever  to  take  place  spontaneously,  no  psychical  improve- 
ment is  manifested  in  the  species  at  large.     One  of  the  most  important  aids  iu 

4 


50  HUMAN   PHYSIOLOGY. 

the  use  and  development  of  the  Human  Mind,  is  the  capacity  for  articulate 
speech;  of  which,  so  far  as  we  know,  Man  is  the  only  animal  in  possession.1 
There  is  no  doubt  that  many  other  species  have  certain  powers  of  communica- 
tion between  individuals ;  but  these  are  probably  very  limited,  and  of  a  kind 
more  allied  to  "  the  language  of  signs,"  than  to  a  proper  verbal  language.  In 
fact,  it  is  obvious  that  the  use  of  a  language  composed  of  a  certain  number  of 
distinct  sounds,  combined  into  words  in  a  multitude  of  different  modes,  requires 
a  certain  power  of  abstraction  and  generalization,  in  which  it  appears  that  the 
lower  animals  are  altogether  deficient.  So,  again,  verbal  language  affords  the 
only  means  whereby  abstract  ideas  can  be  communicated;  and  those  who  have 
perused  the  interesting  narrative  given  by  Dr.  Howe  of  his  successful  training 
of  Laura  Bridgman,  will  remember  how  marked  was  the  improvement  in  her 
mental  condition,  from  the  time  when  she  first  apprehended  the  fact  that  she 
could  give  such  expression  to  her  thoughts,  feelings,  and  desires,  as  should 
secure  their  being  comprehended  by  others. 

16.  This  capacity  for  progress  is  connected  with  another  element  in  Man's 
nature,  which  it  is  difficult  to  isolate  and  define,  but  which  interpenetrates  and 
blends  with  his  whole  psychical  character.  "The  soul,"  it  has  been  remarked, 
"  is  that  side  of  our  nature  which  is  in  relation  with  the  Infinite;"  and  it  is  the 
existence  of  this  relation,  in  whatever  way  we  may  describe  it,  which  seems  to 
constitute  the  distinctive  peculiarity  of  Man.  It  is  in  the  desire  for  an  improve- 
ment in  his  condition,  occasioned  by  an  aspiration  after  something  nobler  and 
purer,  that  the  main-spring  of  human  progress  may  be  said  to  lie ;  among  the 
lowest  races  of  mankind,  the  capacity  exists,  but  the  desire  seems  dormant. 
When  once  thoroughly  awakened,  however,  it  seems  to  "grow  by  what  it  feeds 
on ;"  and  the  advance  once  commenced,  little  external  stimulus  is  needed ;  for 
the  desire  increases  at  least  as  fast  as  the  capacity.  In  the  higher  grades  of 
mental  development,  there  is  a  continual  looking  upwards,  not  (as  in  the  lower) 
towards  a  more  elevated  human  standard,  but  at  once  to  something  beyond  and 
above  man  and  material  nature.  This  seems  the  chief  source  of  the  tendency 
to  believe  in  some  unseen  existence ;  which  may  take  various  forms,  but  which 
seems  never  entirely  absent  from  any  race  or  nation,  although,  like  other  innate 
tendencies,  it  may  be  deficient  in  individuals.  Attempts  have  been  made  by 
some  travellers  to  prove  that  particular  nations  are  destitute  of  it;  but  such 
assertions  have  been  based  only  upon  a  limited  acquaintance  with  their  habits 
of  thought,  and  with  their  outward  observances ;  for  there  are  probably  none 
who  do  not  possess  the  idea  of  some  invisible  Power,  external  to  themselves, 
whose  favor  they  seek,  and  whose  anger  they  deprecate,  by  sacrifice  and  other 
ceremonials.  It  requires  a  higher  mental  cultivation  than  is  commonly  met 
with,  to  conceive  of  this  Power  as  having  a  Spiritual  existence ;  but  wherever 
the  idea  of  spirituality  can  be  defined,  this  seems  connected  with  it.  The  vulgar 
readiness  to  believe  in  ghosts,  demons,  &c.,  is  only  an  irregular  or  depraved 
manifestation  of  the  same  tendency.  Closely  connected  with  it  is  the  desire  to 
participate  in  this  spiritual  existence,  of  which  the  germ  has  been  implanted  in 
the  mind  of  Man,  and  which,  developed  as  it  is  by  the  mental  cultivation  that 
is  almost  necessary  for  the  formation  of  the  idea,  has  been  regarded  by  philoso- 
phers in  all  ages  as  one  of  the  chief  natural  arguments  for  the  immortality  of 
the  soul.  By  this  immortal  soul,  Man  is  connected  with  that  higher  order  of 
being,  in  which  Intelligence  exists,  unrestrained  in  its  exercise  by  the  imper- 
fections of  that  corporeal  mechanism  through  which  it  here  operates;  and  to 
this  state — a  state  of  more  intimate  communion  of  mind  with  mind,  and  of 
creatures  with  their  Creator — he  is  encouraged  to  aspire,  as  the  reward  of  his 
improvement  of  the  talents  here  committed  to  his  charge. 

1  [London  Journal  of  Psychological  Medicine,  for  July  1851;  art.  Instinct  and  Reason, 
by  James  Rumball,  Esq. — ED.] 


CHEMICAL   COMPONENTS   OF   THE   HUMAN   BODY.  51 


CHAPTER    II. 

OP   THE   CHEMICAL   COMPONENTS   OP   THE   HUMAN   BODY,    AND   THE 
CHANGES   WHICH   THEY   UNDERGO   WITHIN   IT. 

THE  body  of  Man,  like  that  of  every  other  Organized  being,  is  composed  of 
elementary  substances  that  exist  abundantly  in  the  Inorganic  Universe,  in  the 
midst  of  which  it  is  placed ;  and  it  is  from  that  Universe,  that  all  its  materials 
are  derived,  either  directly  or  indirectly.  The  atmosphere  supplies  the  Plant 
with  water,  carbonic  acid,  and  ammonia ;  and  at  the  expense  of  the  oxygen,  hy- 
drogen, carbon,  and  nitrogen,  which  it  appropriates  from  these  simple  binary 
compounds,  the  Plant  generates  certain  peculiar  substances,  of  more  complex 
composition,  which  are  applied  in  the  first  place  to  the  extension  of  its  own 
structure,  but  which  are  destined  afterwards  to  constitute  the  materials  of  Ani- 
mal nutrition.  On  the  other  hand,  the  Animal,  availing  itself  of  these  supplies, 
gives  back  to  the  Inorganic  world,  not  only  by  the  decay  of  its  body  after  death, 
but  also  by  the  continual  decomposition  taking  place  in  it  during  life,  the  ele- 
ments which  the  Plant  had  withdrawn  ;  and  this,  for  the  most  part,  in  the  very 
forms  in  which  they  were  originally  combined,  viz.  water,  carbonic  acid,  and 
ammonia.  Most  Plants  also  take  up  mineral  substances  of  some  kind  from  the 
soil,  which  are  united  more  or  less  closely  with  the  organic  compounds  formed 
by  them,  and  which  enter  with  these  into  the  bodies  of  Animals ;  to  be  in  like 
manner  restored  to  the  earth  beneath  them,  by  the  decay  of  the  organisms  of 
which  they  have  formed  part. — As  this  remarkable  sequence  has  been  more 
fully  traced  out  elsewhere,1  and  as  the  Physiologist  has  much  less  to  do  with 
the  Ultimate  components  of  the  Animal  body,  than  he  has  with  the  Organic 
Compounds  which  are  supplied  to  it  as  nutriment  and  of  which  its  fabric  is 
composed,  it  will  not  be  requisite  to  dwell  any  longer  upon  this  part  of  the  sub- 
ject; and  we  may  at  once  pass  on  to  consider  the  nature  and  properties  of  these 
compounds,  and  to  inquire  into  the  metamorphoses  which  they  undergo  within 
the  living  system.  In  doing  this,  it  would  seem  most  appropriate  to  adopt  a 
classification  primarily  founded  rather  upon  their  physiological  than  upon  their 
purely  chemical  relations — upon  the  position  they  hold  in  the  vital  economy, 
rather  than  upon  their  ultimate  composition  or  their  resemblances  to  inor- 
ganic compounds.  We  should  thus  be  led  to  arrange  them  in  four  principal 
groups : — 

I.  The  histogenetic  substances,  which  have  been  introduced  into  the  body  as 
the  materials  of  its  fabric,  or  are  generated  from  these  compounds  subsequently 
to  their  introduction  into  it,  and  are  on  their  way  to  become  part  of  its  organized 
structure  by  progressive  metamorphosis.     These  are  either  organic  or  inorganic 
compounds ;  and  of  the  former,  all,  save  fatty  matters,  belong  to  the  azotized  or 
nitrogenous  group. 

II.  The  calorific  substances,  which  are  either  introduced  into  the  body  as 
components  of  the  food,  or  which  are  formed  within  it — by  the  metamorphosis 

*  See  the  Author's  "Principles  of  Physiology,  General  and  Comparative,"  chap,  v., 
Am.  Ed. 


52  CHEMICAL   COMPONENTS   OF   THE   HUMAN   BODY. 

either  of  the  histogenetic  substances,  or  of  the  components  of  the  tissues  them- 
selves ; — these  substances  are  all  of  the  saccharine  or  of  the  oleaginous  class,  or 
are  derivable  from  them  by  very  simple  transformations. 

III.  The  components  of  the  actual  living  tissues. 

IV.  The  excrementitious  substances,  which  are  formed  within  the  body  as  the 
products  of  the  disintegration  and  retrograde  metamorphosis  of  its  tissues,  and 
which  are  on  their  way  from  these  to  the  outlets  of  the  excretory  apparatus ; — 
these  constituting  a  group  intermediate  in  their  chemical  character  between  the 
foregoing  and  inorganic  matter. 

It  is  to  be  observed,  however,  that  in  this  classification  (as  in  every  other 
assemblage  of  natural  objects)  the  different  groups  are  connected  together  by 
intermediate  links,  which  render  it  impossible  to  isolate  them  completely.  Thus, 
fatty  matters  must  be  looked  upon  as  histogenetic  substances,  since  they  seem 
essential  to  the  production  of  almost  all  the  tissues,  and  enter  largely  into  the 
composition  of  the  adipose  and  nervous ;  yet  their  production  within  the  body 
seems  to  have  most  immediate  reference  to  the  demand  set  up  by  the  com- 
bustive  process,  in  which  a  far  larger  quantity  is  daily  consumed,  than  can  be 
required  for  the  maintenance  of  the  organized  fabric.  So,  again,  fat  as  such 
must  be  regarded  as  a  component  of  the  actual  living  tissues,  and  therefore  as 
belonging  to  the  third  class ;  but  it  does  not,  like  the  histogenetic  substances, 
undergo  organization,  being  simply  combined  mechanically  with  the  other  com- 
ponents, and  being  capable  of  ready  separation  from  them  by  no  other  than 
mechanical  means.  On  the  other  hand,  although  the  third  class  may  be  regarded 
as,  in  great  measure,  chemically  identical  with  the  first,  yet  the  molecular 
condition  of  their  respective  components  is  very  different ;  for  the  properties  of 
the  living  tissues  cannot  be  chemically  examined,  until  they  have  been  deprived 
of  all  those  characters  which  distinguish  them  as  organized  substances,  and  are 
reduced  back  to  a  state  resembling  that  in  which  they  are  first  taken  into  the 
body.  Here  again,  however,  we  meet  with  a  link  of  transition;  for  fibrin,  which 
ranks  as  one  of  the  histogenetic  substances,  may  be  almost  regarded  as  "  liquid 
flesh,"  (§  24,)  and  as  therefore  deserving  of  a  place  in  the  third  class.  And 
lastly,  the  fourth  class  of  substances  is  connected  with  the  third  by  this  circum- 
stance, that  the  excrementitious  substances  are  separated  from  the  blood  into 
which  they  have  been  received  back,  by  the  agency  of  glandular  structures,  of 
whose  organized  tissues  they  form  part  for  a  time,  as  fat  does  of  adipose  tissue  : 
whilst,  again,  they  are  connected  with  the  second  by  the  fact,  that  a  considera- 
ble part  of  the  products  of  disintegration  is  made  use  of  as  calorific  material, 
being  converted  within  the  body  into  saccharine  and  oleaginous  substances  in 
all  respects  resembling  those  taken  in  as  food. — It  will,  therefore,  be  found  con- 
venient to  modify  the  above  classification,  by  arranging  the  substances  which  it 
includes  in  some  degree  according  to  their  Chemical  characters,  still  keeping  in 
view,  however,  their  physiological  destination.  Thus  we  shall  consider  in  the 
1st  place  the  substances  of  the  Albuminous  type,  or  " protein-compounds/'  both 
as  the  materials  for,  and  as  the  components  of,  the  living  tissues;  and  2dly, 
those  of  the  Gelatinous  type,  under  the  same  aspects.  From  these  we  shall 
pass,  Sdly,  to  the  Oleaginous  group,  of  which  the  chief  constituents  may  be 
ranked  both  as  histogenetic  and  as  calorific  substances,  while  some  members  of 
it  should  probably  rank  also  as  products  of  disintegration  :  and  in  connection 
with  these  will  be  described,  4thly,  the  Saccharine  matters,  which  are  also  in 
part  to  be  regarded  as  products  of  disintegration,  and  which  are  more  exclusively 
calorific  than  the  oleaginous,  being  never  applied  to  the  formation  of  tissue  save 
through  conversion  into  fatty  compounds.  In  the  5th  place,  we  shall  pass  under 
review  the  most  notable  of  those  metamorphic  forms,  under  which  the  compo- 
nents of  the  tissues  present  themselves  in  the  principal  Excretions.  And  lastly 


ALBUMINOUS   COMPOUNDS.  53 

we  shall  notice  the  Inorganic  Constituents,  which,  with  the  preceding,  enter  into 
the  composition  of  the  Human  fabric.1 

1.  Albuminous  Compounds. 

18.  Under  this  head  may  be  grouped  together  a  series  of  organic  compounds, 
which  are  of  primary  importance  in  histogenesis  or  the  formation  of  tissue ;  and 
this  not  less  in  the  Vegetable  kingdom  than  in  the  Animal ;  the  original  cell- 
walls  of  the  Plant,  as  well  as  those  of  the  Animal,  being  formed  at  their  ex- 
pense.2 Putting  aside  those  Albuminous  substances  which  are  proper  to  the 
Vegetable  kingdom,  and  restricting  ourselves  to  those  which  are  parts  of  the 
Animal  body  or  are  formed  within  it,  we  find  this  group  to  consist  of  Albumen, 
which  may  be  taken  as  its  type,  with  Casein,  Globulin,  and  Fibrin;  these  are 
also  generally  known  under  the  designation  of  "  Protein-compounds;"3  and  the 
following  properties  are  for  the  most  part  common  to  them  all :  They  occur  in 
two  conditions,  namely,  in  a  soluble,  and  in  an  insoluble  or  scarcely  soluble  state  j 
it  is  in  the  former  condition  that  we  find  them  naturally  existing  in  the  animal 
fluids.  The  soluble  modification,  when  dried,  forms  a  faint  yellow,  translucent, 
friable  mass,  having  no  smell  or  peculiar  taste ;  it  dissolves  in  water,  but  is  in- 
soluble in  alcohol  and  ether ;  it  is  precipitated  by  alcohol  from  the  aqueous 
solution,  after  which  it  is  usually  insoluble  in  water.  The  aqueous  solution  is 
precipitated  by  most  metallic  salts,  and  the  precipitate  generally  contains  the 
acid  and  base  of  the  salt  employed,  in  addition  to  the  protein-compound.  The 
greater  number  cannot  be  precipitated  from  their  aqueous  solution  by  alkalies, 
or  by  most  of  the  vegetable  acids ;  but  they  are  precipitated  by  mineral  acids 
(with  the  exception  of  ordinary  phosphoric  acid)  and  by  tannic  acid ',  and  by 
some  of  these  they  are  converted  into  their  insoluble  form.  Into  this,  more- 
over, the  greater  number  of  them  are  changed  by  boiling ;  and  it  is  in  this 
mode  that  their  insoluble  forms  are  commonly  obtained. — The  insoluble  com- 
pounds, when  dried,  are  white  and  pulverizable,  without  taste  or  smell,  without 
reaction  on  vegetable  colors,  and  insoluble  in  water,  alcohol,  ether,  and  all 
indifferent  menstrua  ;  but  they  are  all  more  or  less  readily  dissolved  by  alkalies, 
from  which  they  may  be  precipitated  by  mere  neutralization  with  acids.  Their 
behavior  towards  different  acids  is  by  no  means  so  uniform,  and  must  be  sepa- 
rately described  in  each  case.  All  of  them,  however,  are  acted  on  in  a  peculiar 
manner  by  concentrated  Nitric  and  Hydrochloric  acids ;  the  former  giving  them 
when  heated  a  deep  lemon-colored  tint ;  whilst  the  latter  causes  them  to 
assume  a  gradually-increasing  Hue  color,  which  becomes  intense  when  they 
are  exposed  to  warmth  and  air.  Again,  they  are  all  dissolved  by  concentrated 
acetic  acid  and  other  organic  acids,  as  well  as  by  phosphoric  acid ;  and  are 
precipitated  from  these  solutions  by  ferrocyanide  of  potassium. — All  the  protein- 
compounds  contain  Sulphur,  which  seems  to  be  one  of  their  essential  constitu- 
ents, not  being  capable  of  entire  separation  without  the  complete  destruction  of 
the  organic  substance,  although  a  part  may  be  withdrawn  by  digestion  with 
fixed  alkalies. 

1  In  the  following  outline,  the  authority  principally  relied  upon  will  be  the  "Physiolo- 
gical Chemistry"  of  Prof.  Lehmann,  of  which  a  translation  (by  Prof.  G.  E.  Day)  is  now 
in  course  of  publication  by  the  Cavendish  Society. 

2  See  "Principles  of  Physiology,  General  and  Comparative,"  Am.  Ed.,  $  136. 

3  Although  this  designation  was  first  given  them  by  Mulder  under  an  idea  (which  has 
since  proved  to  be  erroneous)  that  he  could  obtain  from  either  of  them  a  certain  organic 
base,  free  from  sulphur  and  phosphorus,  to  which  he  gave  the  name  of  Protein,  yet  it  has 
been  found  to  be  so  convenient  both  in  Chemistry  and  Physiology,  that  there  seems  to  be 
a  general  accordance  in  its  retention.     See  Lehmann's  "Physiological  Chemistry,"  vol.  i. 
p.  326. 


54  CHEMICAL   COMPONENTS   OP   THE   HUMAN   BODY. 

19.  All  the  Protein-compounds  are  very  liable  to  decomposition;  this  change 
taking  place  in  them  spontaneously,  when  they  are  exposed  to  the  air  at  ordinary 
temperatures ;  and  being  very  readily  induced  by  oxidizing  agents,  alkalies,  &c., 
the  effect  of  which  is  promoted  by  heat.  As  yet,  however,  no  satisfactory  clue 
has  been  obtained  to  the  very  complex  composition  of  these  substances ;  since 
they  cannot  be  resolved  by  analysis  (like  complex  inorganic  bodies)  into  two  or 
more  compounds  whose  synthesis  reproduces  the  original.  Still,  it  is  very  inte- 
resting to  observe  that,  whilst  the  ultimate  decomposition  of  the  protein-com- 
pounds resolves  them  (with  oxygen  taken  from  the  atmosphere)  into  water, 
carbonic  acid,  and  ammonia,  various  organic  compounds  may  be  generated  by 
a  less  complete  separation  of  their  components.  Thus  by  the  action  of  oxidiz- 
ing substances,  the  formic,  acetic,  butyric,  caproic,  and  other  organic  acids  of 
the  same  group,  which  occur  naturally  in  the  animal  body,  may  be  obtained ; 
and  there  is  a  strong  probability  that  the  ordinary  fatty  acids  may  be  generated 
by  a  similar  change  (§  40). — Again,  by  the  prolonged  action  of  caustic  alkalies 
upon  the  protein-compounds,  a  crystalline  substance  is  obtained,  which  is  termed 
Leucine;  this  forms  colorless  scales,  destitute  of  taste  and  odor;  it  is  soluble 
in  water,  and  sublimes  unchanged.  It  consists  of  12C,  12H,  IN,  40.  There 
is  not  at  present  any  evidence  that  this  substance  is  ever  produced  in  the  liv- 
ing body;  but  a  strong  interest  attaches  to  it,  from  the  fact  that  it  may  be 
procured  from  .Gelatin,  as  well  as  from  the  Protein-compounds.  Another 
compound  obtained  by  the  same  reaction  is  called  Tyro&ine;  it  crystallizes  in 
brilliant  needles ;  and  its  formula  is  16C,  9H,  IN,  50. — The  tendency  to 
decomposition  which  exists  in  this  class  of  substances,  not  merely  occasions  the 
re-arrangement  of  their  own  elements  in  new  compounds  of  a  different  character, 
but  also  tends  to  produce  similar  changes  in  other  substances ;  and  it  is  probable 
that  this  kind  of  agency  takes  place  to  a  great  extent  in  the  living  body.  Thus 
a  protein-compound,  in  a  certain  stage  of  decomposition,  will  convert  starch  into 
sugar;  in  a  more  advanced  state  of  change,  it  will  convert  sugar  into  lactic  acid, 
mannite,  and  vegetable  mucus,  or  into  alcohol  and  carbonic  acid ;  and  by  the 
same  agency,  lactic  acid  may  be  resolved  into  butyric  acid,  hydrogen,  and  car- 
bonic acid.1  This  property  of  exciting  change  in  other  substances,  whilst 
themselves  passing  into  decay,  makes  it  very  important  that  the  history  of  the 
protein-compounds  in  the  living  body  should  be  fully  made  out ;  since  it  is 
obvious  that  they  are  not  merely  required  as  histogenetic  materials,  but  that 
they  also  take  an  important  part  in  the  transformation  of  other  substances  by 
their  action  as  ferments. 

20.  Of  the  whole  series  of  protein-compounds,  Albumen  is  obviously  the  one 
which  may  be  considered  as  the  proper  pabulum  of  the  Animal  tissues  gene- 
rally; since  we  have  evidence  that  from  it,  in  combination  with  fatty  matter  and 
mineral  ingredients,  all  the  tissues  of  the  body  may  be  generated.  The  store 
of  nutriment  laid  up  within  the  egg,  from  which  in  due  time  the  chick  is  de- 
veloped, with  its  bones,  muscles,  nerves,  tendons,  ligaments,  membranes,  skin, 
horny  bill,  feathers,  &c.,  is  composed  of  nothing  else ;  and  the  albumen  of  the 
blood  of  the  adult  animal  is  continually  being  withdrawn  from  it,  to  be  applied 
in  like  manner  to  the  maintenance  of  these  various  tissues.3  We  shall  find, 
moreover,  that  the  other  histogenetic  substances,  when  employed  as  food,  must 
be  reduced  to  the  state  of  albumen,  before  they  can  be  appropriated  by  the 
living  system.  The  properties  of  Albumen  may  be  studied  in  the  white  of  the 
egg,  or  in  the  serum  of  the  blood,  from  either  of  which  situations  it  may  be 

1  See  Prof.  Liebig's  "Familiar  Letters  on  Chemistry,"  3d  ed.  p.  207. 

2  Even  if  it  should  be  proved  that  the  Gelatigenous  tissues  are  ever  formed  from  Gelatin 
taken  in  as  food,  which  the  Author  believes  to  be  highly  improbable  (see  \  35),  yet  there 
can  be  no  question  that  they  are  formed  from  the  albuminous  part  of  the  blood,  when  (as 
in  all  Herbivorous  animals)  the  aliment  contains  no  gelatinous  component. 


ALBUMINOUS   COMPOUNDS.  65 

obtained  in  a  nearly  pure  state  by  very  simple  means.  These  two  forms  of  it, 
however,  are  not  precisely  identical;  indeed,  it  appears  from  recent  inquiries 
that  striking  differences  are  produced  in  albumen,  not  merely  by  the  presence 
of  some  other  body,  such  as  an  alkali  or  a  salt,  but  by  the  different  proportions 
in  which  this  occurs;  and  hence  it  is  that  various  and  contradictory  statements 
have  been  made,  in  reference  to  the  properties  of  this  substance.  The  follow- 
ing are  the  facts  of  most  physiological  interest.  —  In  the  before-mentioned 
animal  fluids,  as  well  as  in  several  others,  Albumen  exists  in  its  soluble  form, 
but  not  in  an  isolated  state ;  for  it  is  united  with  soda  as  an  acid  to  its  base, 
and  thus  may  be  formed  a  basic,  neutral,  or  acid  albuminate  of  soda.  The 
basic  compound,  which  contains  about  1£  per  cent,  of  soda,  and  gives  a 
slightly  alkaline  reaction,  is  the  one  which  ordinarily  presents  itself  in  normal 
blood,  as  well  as  in  the  egg;  but  diseased  blood  (as  first  ascertained  by  Scherer) 
very  frequently  contains  a  neutral  albuminate,  the  characteristic  of  which  is, 
that  its  solution  becomes  turbid  on  the  simple  addition  of  water ;  and  it  has  been 
shown  by  Lehmann  that  this  occurs  normally  in  the  blood  of  the  hepatic  and 
splenic  veins,  that  of  the  former  having  been  deprived  of  a  portion  of  its  alkali 
whilst  passing  through  the  liver,  and  that  of  the  latter  having  received  an 
additional  charge  of  its  acid  in  the  splenic  parenchyma. — The  ordinary  basic 
albuminate  of  soda,  or  sodo-albumen,  is  far  more  soluble  in  water  than  is  pure 
albumen,  which,  indeed,  when  entirely  separated  from  all  other  substances,  is 
probably  not  soluble  at  all.  It  differs  from  pure  albumen,  moreover,  in  the 
mode  in  which  it  coagulates  on  the  application  of  heat;  for  whilst  the  latter 
separates  in  flakes,  sodo-albumen  forms  a  white  gelatinous  mass,  or,  if  the  fluid 
be  much  diluted,  makes  itself  apparent  only  by  a  milky  or  opalescent  turbidity. 
The  alkaline  reaction  of  a  solution  of  sodo-albumen  becomes  more  marked  on 
boiling,  which  indicates  that  at  least  a  portion  of  the  alkali  must  be  separated 
from  the  albumen  on  its  coagulation;  and  according  to  Prof.  Liebig  (op.  cit.  p. 
387,  note),  a  new  compound  of  albumen  with  phosphoric  acid  and  lime  is  then 
probably  formed.  A  moderately  strong  solution  of  pure  albumen  in  water  be- 
comes turbid  at  140°,  becomes  completely  insoluble  at  145°,  and  separates  in 
flakes  at  167°;  when  excessively  diluted,  however,  no  turbidity  can  be  produced 
by  a  less  heat  than  194° ;  and  coagula  will  only  separate  after  it  has  been  boiled  a 
considerable  time.  After  having  been  dried  in  vacuo,  however,  or  at  a  temperature 
below  120°,  Albumen  may  be  heated  to  212°  without  passing  into  the  insoluble 
condition.1  Albumen  may  be  precipitated  from  an  aqueous  solution  by  diluted 
alcohol;  but  it  does  not  pass  into  the  insoluble  form,  unless  a  large  quantity  of 
strong  alcohol  be  added.  It  is  also  precipitated  by  creosote.  Albumen  is  con- 
verted into  the  insoluble  form  by  most  acids;  but  it  is  not  precipitated  by  the 
mineral  acids,  unless  they  are  added  in  excess;  and  the  organic  acids,  with  the 
exception  of  the  tannic,  do  not  throw  it  down.  It  is  converted  into  the  insolu- 
ble form  by  alkalies,  but  is  not  precipitated  by  them,  being  held  up  by  their 
presence.  The  greater  number  of  metallic  salts  precipitate  albumen,  which 
generally  passes  into  the  insoluble  state,  and  enters  into  combination,  either 
with  the  basic  salt  itself,  or  with  its  acid  and  its  base  separately ;  one  of  these 
salts,  the  albuminate  of  the  chloride  of  mercury,  is  of  much  interest,  as  being 
that  which  is  produced  by  the  mixture  of  a  solution  of  albumen  with  one  of 
corrosive  sublimate. — The  following  is  the  composition  of  Albumen,  according 
to  the  most  recent  analyses  of  two  eminent  chemists. 

1  The  fact  that  dry  Albumen  may  be  heated  to  a  much  higher  temperature,  without 
passing  into  the  insoluble  form,  than  Albumen  in  solution  can  be,  is  of  much  interest,  in 
relation  to  the  experiments  of  Doyere  and  others  upon  the  tenacity  of  life  of  the  Tardi- 
grade tribe  of  Rotifera ;  for  it  has  been  found  that,  when  completely  desiccated,  the  bodies 
of  these  animals  might  be  exposed  to  a  heat  of  250°,  without  the  destruction  of  their 
vitality.  See  "Princ.  of  Phys.,  Gen.  and  Cornp.,"  Am.  Ed.,  g  65. 


56  CHEMICAL   COMPONENTS   OP   THE    HUMAN   BODY. 

gcherer.  Mulder. 

Carbon 54.9  53.5 

Hydrogen 7.0  7.0 

Nitrogen              15.7  15.5 

Oxygen         )  f  22.0 

Sulphur        V 22.4  -I    1.6 

Phosphorus  J  (   0.4 

100.0  100.0 

It  has  lately  been  affirmed,  however,  by  Prof.  Liebig,  that  Phosphorus  is  not 
(like  Sulphur)  a  true  constituent  of  Albumen,  or  of  any  of  the  Protein-com- 
pounds ;  and  that  it  has  no  existence  in  any  article  of  food,  or  in  any  tissue  of 
the  body,  save  in  combination  with  oxygen  as  phosphoric  acid.1  Albumen  seems 
never  to  occur  in  the  animal  body,  except  in  such  intimate  union  with  fatty  and 
mineral  substances,  that  it  is  with  difficulty  separated  from  them.  The  quantity 
of  these  is  variable;  but  altogether  they  usually  amount  to  at  least  6  per  cent., 
of  which  from  1  to  2.5  per  cent,  consists  of  phosphate  of  lime. 

21.  As  a  general  rule,  Albumen  is  found  in  all  the  nutritive  fluids  of  the 
body,  as  the  Blood,  the  Chyle,  the  Lymph,  and  the  serous  exudation  which 
percolates  through  the  interstices  of  the  tissues.     From  several  of  the  tissues, 
also,  it  may  be  obtained  in  considerable  abundance ;  but  it  is  not  always  easy 
to  say  whether  it  is  a  natural  constituent  of  such  tissues,  or  whether  it  is  simply 
left  by  the  fluid  with  which  they  were  charged.     It  has  been  recently  affirmed 
by  Prof.   Liebig,  however,  that  the  characteristic  solid  constituent  of  Muscle, 
which  has  been  usually  known  under  the  designation  of  fibrin,  is  in  reality 
essentially  conformable  in  all  its  chemical  relations  with  coagulated  Albumen ; 
and  is  at  any  rate  much  more  nearly  allied  to  it,  than  it  is  to  the  fibrin  of 
the  blood.     And  if  this  be  true,  it  is  probable  that  the  same  may  be  said  of  the 
watts  of  the  component  cells  of  the  glandular,  nervous,  adipose,  epidermic,  and 
other  tissues,  however  different  may  be  the  character  of  their  contents ;  and 
that  Albumen  is,  in  fact,  the  fundamental  constituent  of  all  such  tissues  as  do 
not  belong  to  the  gelatinous  type.     It  cannot  be  said  that  Albumen  is  a  normal 
constituent  of  any  of  the  secreted  fluids,  such  as  the  salivary,  gastric,  or  pancre- 
atic; the  peculiar  organic  constituents  of  these  being  apparently  albuminous 
substances  in  a  state  of  change.     And  among  the  proper  excretory  matters,  it 
is  certain  that  albumen  is  never  found  but  in  consequence  of  morbid  action ;  its 
appearance  indicating  either  disease  of  the  excreting  organ,  or  a  marked  alter- 
ation either  in  the  composition  of  the  blood  or  in  the  mode  of  its  circulation. 

22.  The  place  of  Albumen  is  occupied  in   Milk  by  the  substance  termed 
Casein,  which  seems  to  differ  from  it  less  in  ultimate  composition,  than  it  does 
in  chemical  properties.     Casein,  like  albumen,  occurs  in  the  soluble  and  inso- 
luble states ;  but  the  passage  from  one  to  the  other  takes  place  under  different 
conditions.    It  appears,  from  the  late  researches  of  Scherer  and  Rochleder,  that 
pure  Casein  is  insoluble  in  water,  and  that  the  soluble  casein  is   a  combination 
of  pure  casein  with  an  alkaline  or  earthy  base,  the  withdrawal  of  which  is  the 
cause  of  its  precipitation  by  acids.3     In  this  precipitation,  the  casein  is  not 
reduced  to  its  insoluble  form  ;  as,  by  neutralizing  the  acids  with  alkalies  or  me- 
tallic oxides,  it  again  dissolves.     Casein  is  not  (like  Albumen)  made  to  coagu- 
late from  its  ordinary  state  of  solution  by  the  agency  of  heat ;  and  the  precipi- 
tate thrown  down  by  the  addition  of  a  small  quantity  of  alcohol  is  readily 
dissolved  again  in  water.    The  most  characteristic  distinctions  between  Albumen 
and  Casein,  however,  are  afforded  by  the  peculiar  action  of  the  lactic  and  acetic 
acids,  and  of  the  "  rennet"  of  the  calf's  stomach,  upon  the  latter ;  for  Casein 

1  See  his  "  Familiar  Letters  on  Chemistry,"  pp.  437  and  451. 

2  See  the  Memoir  of  Dr.  Panum,  hereafter  cited. 


ALBUMINOUS  COMPOUNDS.  57 

is  very  readily  precipitated  by  those  acids,  although  they  do  not  form  combina- 
tions with  it,  and  it  is  made  to  coagulate  by  contact  with  an  excessively  small 
portion  of  rennet ;  whilst  neither  of  these  reagents  has  any  effect  upon  ordinary 
Albumen.1 — The  analyses  given  by  different  chemists  of  the  ultimate  composi- 
tion of  Casein,  differ  quite  as  much  from  each  other,  in  regard  to  the  propor- 
tions of  Oxygen,  Hydrogen,  Carbon,  and  Nitrogen,  which  it  contains,  as  they 
do  from  the  analyses  of  Albumen  already  cited ;  and  the  only  positive  diversity 
between  the  two  substances,  that  can  be  detected  by  ultimate  analysis,  seems  to 
be  in  the  absence  of  phosphorus  from  casein,  and  in  the  smaller  proportion  of 
sulphur  which  it  includes. — Casein,  like  albumen,  never  occurs  in  nature  in  an 
isolated  form,  but  is  intimately  blended  with  other  substances;  and  it  is  specially 
remarkable  for  the  quantity  of  Phosphate  of  Lime  which  is  incorporated  with 
it,  as  much  as  6  per  cent,  of  this  earthy  salt  being  usually  obtainable  from  it. — 
It  is  in  the  milk  of  the  Mammalian  female,  that  we  meet  with  Casein  in  the 
greatest  abundance;  and  it  must  be  formed  in  that  secretion  either  from  the 
albumen  of  her  blood,  or  at  the  expense  of  her  solid  tissues.  When  introduced 
as  food  into  the  stomach  of  her  offspring,  it  is  there  completely  coagulated,  and 
seems  to  be  reduced  back  in  the  digestive  process  to  the  condition  of  Albumen, 
as  it  also  is  when  used  as  food  in  its  coagulated  state  by  the  adult.  Casein  has 
been  obtained  in  considerable  quantity  from  the  blood  of  puerperal  women,  in 
whom  the  secretion  of  milk  has  been  checked ;  but  it  seems  doubtful  if  true 
casein  is  ever  a  normal  constituent  of  the  blood.  Various  experimenters  have 
affirmed  its  presence ;  but  their  results  do  not  for  the  most  part  seem  trust- 
worthy, since  they  are  invalidated  by  certain  fallacies  which  have  been  pointed 
out  by  Prof.  Lehmann  (op.  cit.  vol.  i.  p.  380).  The  existence  of  Casein  in 
ordinary  blood-serum  has  been  more  recently  affirmed  by  Dr.  Panum ;  but  his 
experiments  are  scarcely  satisfactory,  since  it  appears  by  no  means  impossible 
that  what  he  represents  to  be  Casein  may  be  nothing  else  than  the  neutral 
albuininate  of  soda  (§  20),  which  is  precipitated,  as  we  have  seen,  by  the  addi- 
tion of  water,  and  which  may  also  be  thrown  down  by  acetic  acid.3 — It  is  inte- 
resting to  remark,  however,  that  from  the  latter  inquiries  of  Prof.  Lehmann,  it 
seems  by  no  means  improbable  that  the  Vitellin,  which  forms  the  albuminous 
body  of  the  yolk  of  the  egg,  and  which  has  been  described  as  a  peculiar  com- 
pound intermediate  between  albumen  and  fibrin,  is  in  reality  a  mixture  of  Albu- 
men with  Casein.  "  The  amorphous  dark  granules  of  the  yolk/'  he  says,  "  are 
pure  casein  free  from  alkali,  which,  like  ordinary  casein,  is  rich  in  phosphate  of 
lime ;  while  in  the  proper  intercellular  fluid  of  the  yolk,  there  is  no  casein,  but 

1  It  is  shown  by  Prof.  Lehmann,  however,  that  under  certain  circumstances  Albumen 
may  be  precipitated  by  acetic  acid ;  and  that  even  the  rennet-test  is  liable  to  fallacies. 
It  is  very  commonly  supposed  that  the  coagulation  of  Casein  in  milk,  when  treated  with 
rennet,  is  due  to  the  action  of  rennet  as  a  ferment  upon  the  sugar  of  milk,  the  lactic  acid 
thus  formed  being  the  real  precipitant  of  the  casein.     The  experiments  cited  by  Prof. 
Lehmann,  however,  render  it  probable  that  the  action  of  rennet  upon  casein  does  not  re- 
quire the  intermediation  of  lactic  acid.     (Op.  cit.  pp.  375-381.) 

2  It  has  been  ascertained  by  Dr.  Panum,  that  pure  Casein  from  milk  is  readily  soluble 
in  water  containing  a  certain  quantity  of  phosphate  of  soda,  but  is  precipitated  when  this 
solution  is  too  much  diluted  ;  and  this  fact  he  applies  to  the  explanation  of  the  turbidity 
which  he  has  found  to  be  frequently  produced  in  ordinary  blood-serum  by  the  addition  of 
acetic  acid,  or  by  dilution  with  water,  or  by  both  means  combined ;  this  reaction  being 
supposed  by  him  to  take  place  under  the  following  conditions. — The  (supposed)  Casein, 
united  with  soda,  is  held  in  solution  by  the  salts  which  are  present,  especially  phosphate 
of  soda ;  if  its  quantity  be  very  large,  the  solvent  power  of  the  salts  is  sufficiently  weakened 
by  the  addition  of  water  to  occasion  its  precipitation ;  and  the  addition  of  acetic  acid, 
without  dilution,  will  produce  the  same  effect  by  withdrawing  its  soda  ;  but  if  its  quantity 
be  smaller,  its  precipitation  can  only  be  accomplished  by  the  dilution  of  the  solution,  and 
the  addition  of  acetic  acid,  conjointly. — See  Dr.  Panum's  Memoir  in  the  "Bibliothek  fur 
Laager,"  for  Jan.  1850,  and  the  "London  Journal  of  Medicine,"  July,  1850. 


58  CHEMICAL   COMPONENTS   OF   THE    HUMAN   BODY. 

merely  dissolved  albumen  poor  in  alkali."  On  shaking  fresh  yolk  with  ether 
and  water,  there  is  formed  under  the  yellow  fatty  stratum  of  ether,  a  white  and 
somewhat  viscid  mass,  which  has  been  mistaken  for  Vitellin  coagulated  by 
ether ;  but  if  this  substance  be  carefully  separated  by  filtration  and  washing,  it 
is  found  to  bear  a  perfect  resemblance  to  pure  casein,  answering  to  all  the  casein- 
tests  (including  that  of  rennet),  and  merely  containing  additionally  a  little  albu- 
men poor  in  salts.1 

23.  Nearly  allied  to  Albumen,  and  differing  from  it  rather  in  its  physiological 
than  in  its  chemical  relations,  is  another  substance  which  is  largely  present  in 
the  Human  body ;  namely,  Globulin.    This  is  one  of  the  constituents  of  the  red 
blood-corpuscles,  and  is  also  found  in  the  peculiar  cells  of  the  crystalline  lens; 
and  is  probably  to  be  regarded  as  albumen  somewhat  changed  by  the  peculiar 
action  of  these  bodies.     It  cannot  be  certainly  shown  to  differ  from  Albumen 
in  ultimate  composition,  except  that  (like  Casein)  it  contains  no  phosphorus; 
but  it  is  not  coagulated  by  heat  with  nearly  the  same  facility,  whilst,  on  the  other 
hand,  it  is  readily  precipitated  by  acetic  acid.     In  these  respects,  Globulin  may 
be  considered  as  intermediate   between  Albumen  and   Casein;  and  it  seems 
further  to  correspond  with  the  latter  substance,  in  being  quite  insoluble  in  water 
when  detached  from  all  k;s  combinations,  being  only  held  in  solution  by  union 
with  an  alkali,  or  by  the  presence  of  phosphate  of  soda.     In  its  coagulated 
state,  it  cannot  be  distinguished  from  other  protein-compounds.     The  quantity 
of  saline  matter  usually  combined  with  globulin  seems  to  be  small ;  the  soluble 
salts  amounting  to  about  1.5  per  cent,  and  the  phosphate  of  lime  to  no  more 
than  0.25  per  cent. 

24.  The  substance  known  as  Fibrin  is  almost  as  closely  accordant  with  Albu- 
men as  are  the  foregoing,  in  regard  to  its  ultimate  composition  and  its  purely 
chemical  relations;  but  it  differs  widely  in  its  physiological  characters,  which 
are  such  as  distinctly  indicate  that  it  possesses  properties  of  a  different  nature 
from  its  chemical  and  physical  attributes,  and  deserving  to  be  ranked  as  vital. 
Neither  Albumen,  nor  any  other  of  the  protein-compounds  already  described, 
presents  the  slightest  tendency  to  pass  spontaneously  into  any  condition  that 
presents  the  least  trace  of  organization;  the  masses  formed  by  their  coagulation, 
in  whatever  way  this  may  have  been  brought  about,  being  mere  aggregations  of 
amorphous  particles,  entirely  destitute  of  structure.     But  it  is  the  characteristic 
property  of  Fibrin,  that,  although  existing  in  solution  in  certain  animal  fluids, 
so  long  as  they  are  contained  within  the  living  vessels,  it  tends  to  separate  itself 
in  the  solid  form,  that  is,  to  coagulate  spontaneously,  when  no  longer  subjected 
to  vital  influence,  as  when  withdrawn  from  the  living  body,  or  when  the  body 
itself  dies ;  and,  further,  that  the  coagulum,  when  formed  under  favorable  cir- 
cumstances, exhibits  a  definite  organic  structure,  of  a  very  simple  kind  indeed, 
but  such  as  closely  resembles  that  of  tissues  which  form  a  large   part  of  the 
animal  fabric. — This  substance  is  one,  consequently,  of  great  physiological  im- 
portance.    It  is  found  in  all  fluids  that  are  being  applied  to  the  nutrition  of 
living  tissues,  or  are  in  immediate  preparation  for  that  purpose :  thus  it  is  one 
of  the  most  characteristic  ingredients  of  the  Blood;  it  also  presents  itself  in 
Chyle  and  Lymph;  and  it  is  a  component  of  all  those   exudations  which  are 
designated  as  "plastic,"  from  their  tendency  to  give  origin  to  new  tissues.     On 
the  other  hand,  it  is  entirely  absent  from  all  the  normal  secreted  fluids,  whether 
these  are  destined  for  special  uses  within  the  body,  or  are  to  be  carried  forth 
and  discharged  as  the  products  of  its  decay.     All  these  circumstances  seem  to 
point  very  decidedly  to  the  conclusion,  that  Fibrin  is  to  be  considered  as  a 
hutoffenetic  substance  in  the  act  of  conversion  into  living  tissue,  its  molecules 
having  a  tendency  to  assume  one  of  the  peculiar  arrangements  which  is  charac- 

•  "Lehrbucli  der  physiologischen  Chemie,"  Band  ii.  p.  349. 


ALBUMINOUS   COMPOUNDS.  59 

teristic  of  organization.  Whether  all  Albuminous  substances,  however,  must 
pass  through  the  condition  of  Fibrin,  before  they  can  be  applied  to  the  purposes 
of  nutrition,  is  a  question  which  cannot  as  yet  be  determined ;  and  it  is  safer, 
in  the  present  state  of  our  knowledge  (or  rather  of  our  ignorance),  not  to  dog- 
matize upon  the  subject. — We  shall  first  consider  the  chemico-physical,  and  then 
the  physiological  or  vital  properties  of  Fibrin. 

25.  The  ultimate  composition  of  Fibrin  cannot  be  said  with  any  degree  of 
certainty  to  diifer  from  that  of  Albumen,  as  will  be  seen  from  the  following 
analytical  results,  which  scarcely  diifer  more  from  those  already  given  for  Albu- 
men, than  they  differ  from  each  other : — 

Scherer.  Mulder. 

Carbon       T        /"    .         .         .         ."'  '  .    '  53.6  52.7 

Hydrogen   ....         i1    :'V'"/;V  6.9  6.9 

Nitrogen     .         .  -'-;V  t^J.*'.  £   v..- ;•;;..». --.s  15.7  15.4 

Oxygen         )  (23.5 

Sulphur        L      .         ,.,.':*..*,«,     .,  ...v,,.*  23.8  \    1.2 

Phosphorus  J  (   0.3 

100.0  100.0 

Most  of  the  later  elementary  analyses  of  Fibrin  support  the  view,  that  there  is 
rather  a  larger  quantity  of  oxygen  contained  in  it  than  in  Albumen ;  but  all 
these  results  are  liable  to  fallacy,  arising  from  the  extreme  difficulty  of  obtain- 
ing fibrin  in  a  perfectly  pure  state;1  and  it  would  not  be  safe  to  rest  much  upon 
them.  So  long  as  Fibrin  exists  in  solution  (as  in  frog's  blood,  diluted  with 
sugared  water,  and  deprived  of  its  corpuscles  by  filtration),  it  can  scarcely  be 
distinguished  from  Albumen  by  the  effects  of  reagents  upon  it,  nearly  all  sub- 
stances which  precipitate  the  one,  precipitating  the  other  also;  ether,  however, 
is  an  exception,  for  it  causes  fibrin  to  coagulate,  whilst  the  albumen  remains 
dissolved. — In  its  spontaneously  coagulated  state,  Fibrin  is  a  yellowish,  opaque, 
fibrous  mass,  insoluble  in  water,  alcohol,  and  ether;  it  possesses  in  this  condi- 
tion somewhat  of  the  softness  and  elasticity  which  characterize  the  /flesh  of 
animals,  and  contains  about  three-fourths  of  its  weight  of  water.  By  drying, 
this  water  may  be  expelled,  and  the  fibrin  becomes  a  hard  and  brittle  substance ; 
but,  like  flesh,  it  imbibes  water  again  when  moistened,  and  recovers  its  original 
softness  and  elasticity.  Fibrin  in  this  state  is  remarkably  distinguished  from 
coagulated  Albumen,  by  its  power  of  decomposing  the  peroxide  of  hydrogen, 
on  which  albumen  has  no  effect.  When  Fibrin  is  treated  with  strong  acetic  acid, 
it  imbibes  the  acid,  and  swells  up  into  a  transparent  colorless  jelly,  which  is 
soluble  in  hot  water;  this  peculiar  change  showing  a  marked  difference  between 
fibrin  and  albumen,  and  indicating  the  relationship  of  the  former  to  the  sub- 
stance of  the  gelatigenous  tissues  (§  29).  Again,  when  treated  with  water 
acidified  with  one-tenth  part  of  hydrochloric  acid,  Fibrin  swells  up,  and  forms 
a  gelatinous  mass,  returning  to  its  original  volume  when  more  acid  is  added, 
and  again  swelling  up  on  the  addition  of  water,  without  any  notable  proportion 
of  it  being  dissolved;  in  this  respect  differing  completely  from  the  substance  of 
Muscle,  which  is  readily  dissolved  by  dilute  hydrochloric  acid.3  Coagulated 
fibrin,  however,  may  be  converted  into  a  substance  closely  resembling  albumen, 
by  means  which  tend  to  destroy  its  peculiar  molecular  arrangement.  This 
change  happens,  indeed,  as  a  simple  result  of  incipient  decomposition ;  for  under 
exposure  to  air,  and  with  the  presence  of  a  sufficient  amount  of  water,  Fibrin 
at  first  dissolves  away  into  a  substance,  which,  like  albumen,  is  coagulable  by 
heat;  during  this  process  it  attracts  oxygen;  and  a  continuance  of  the  decom- 

1  See  Lehmann,  op.  cit.  p.  353. 

2  See  Prof.  Liebig's  important  Memoir  on  the  distinction  between  the  Fibrin  of  the 
Blood  and  that  of  Muscle,  in  the  "Annalen  der  Chemie  und  Pharmacie,"  Band  Ixxiii. 


60  CHEMICAL   COMPONENTS   OF   THE   HUMAN   BODY. 

position  leads  to  the  development  of  ammonia,  carbonic  acid,  butyric  acid,  and 
sulphuretted  hydrogen,  and  leaves  a  residue  consisting  principally  of  leucine  and 
tyrosine  (§  19).  It  was  long  since  pointed  out  by  Denis,1  that  spontaneously- 
coagulated  fibrin  may  also  be  reduced  to  a  condition  closely  resembling  that  of 
albumen,  by  the  action  of  nitrate  of  potash  (this  action,  as  is  justly  remarked 
by  Lehmann,  not  being  one  of  mere  solution,  but  of  transformation);  and  it 
has  been  since  ascertained  by  Zimmermann,  that  various  saline  solutions  will 
have  the  same  effect  upon  fibrin  digested  in  them.2  Although  there  is  much 
discrepancy  in  the  evidence  on  this  point,  yet  on  the  whole  it  seems  that  the 
fibrin  of  venous  blood  is  thus  taken  up  more  readily  than  the  fibrin  of  arterial 
blood,  or  than  fibrin  which  has  been  exposed  for  some  time  to  the  air;  and  that 
exposure  to  the  air  has  the  effect  of  precipitating  the  dissolved  protein-compound 
in  fine  flocks;  thus  indicating  that  arterial  fibrin  is  in  a  state  of  higher  oxida- 
tion than  venous  fibrin,  and  is  further  removed  from  the  state  of  albumen. 
The  solution  thus  obtained  coagulates  in  flakes  at  the  temperature  of  about  162° ; 
but  it  differs  from  an  albuminous  solution  in  being  strongly  precipitated  by  acetic 
acid;  whilst,  on  the  other  hand,  it  is  not  coagulated  by  ether,  as  is  true  fibrin 
in  solution. — When  Fibrin  is  boiled,  moreover,  it  is  converted  into  a  substance 
which  can  scarcely  be  distinguished  chemically  from  coagulated  albumen;  and 
this  operation  prevents  it  from  being  converted  into  a  soluble  albumen-like  sub- 
stance by  digestion  in  saline  solutions.  By  continued  boiling,  however,  with 
free  exposure  to  the  air,  its  character  is  further  changed ;  and  it  is  converted 
into  the  substance  termed  by  Mulder  tritoxide  of  protein  (§  29),  which  may  also 
be  obtained  by  treating  albumen  in  the  same  manner. — Thus  all  the  means 
which  tend  to  bring  back  Fibrin  to  the  condition  of  a  mere  chemical  compound, 
by  destroying  that  peculiar  molecular  arrangement  which  its  particles  have 
acquired,  tends  to  reproduce  in  it  the  properties  of  ordinary  Albumen.  Like 
Albumen,  moreover,  Fibrin  is  always  in  a  state  of  intimate  union  with  fatty 
substances;  about  2£  per  cent,  of  these  being  usually  associated  with  it. 
Mineral  substances,  especially  phosphate  of  lime,  also  present  themselves  in  its 
ash;  but  usually  in  smaller  proportion  than  in  that  of  albumen. 

26.  The  process  of  solidification  of  Fibrin,  as  ordinarily  seen  in  the  coagula- 
tion of  the  Blood  when  drawn  from  the  vessels  of  the  living  body,  is  somewhat 
complicated  by  the  presence  of  the  corpuscles  which  are  floating  in  the  fibrinous 
fluid ;  and  it  can  be  better  watched  when  these  corpuscles  have  been  separated 
from  it,  either  by  filtration,  or  by  subsidence.  Thus  when  the  coagulation  takes 
place  at  an  unusually  long  interval  after  the  blood  has  been  drawn  (as  com- 
monly happens  in  the  case  of  inflammatory  blood),  the  red  corpuscles  sink 
towards  the  bottom,  in  virtue  of  their  higher  specific  gravity,  and  the  fibrinous 
fluid  is  left  free  from  them  ;  and  the  same  end  may  be  obtained  by  covering  the 
blood  with  a  layer  of  oil,  which,  by  excluding  the  atmosphere,  retards  its  coagu- 
lation ;  or  by  treating  it  wifch  dilute  solutions  of  alkaline  sulphates,  nitrates,  &c., 
which  have  a  similar  retarding  effect.  The  first  indication  of  the  approaching 
change,  as  seen  with  a  microscope  in  a  thin  film,  consists  in  the  appearance  of 
minute  molecular  points,  which  are  scattered  over  the  field;  and  from  these 
speedily  arise  fine  thread-like  prolongations,  which  radiate  irregularly  from 
them,  crossing  those  that  arise  from  other  centres,  and  at  last  covering  the 
whole  field  of  view  as  with  a  delicate  but  somewhat  irregular  cobweb.  This 
fibrillation  seems  to  bear  a  certain  analogy  to  crystallization,  being  the  result  of 
forces  which  tend  to  withdraw  the  solid  particles  from  their  state  of  solution  in 
the  liquid,  and  to  bring  them  together  in  a  certain  definite  mode  of  aggregation ; 
and  there  are  certain  peculiarities  in  the  process,  which  to  some  extent  bear  out 

1  "Arch.  g6n.  de  Med.,"  3ieme  Ser.  torn.  i.  p.  171. 
8  "Casper's  Wochensckrift,"  No.  30,  1843. 


ALBUMINOUS   COMPOUNDS.  61 

this  analogy.  Thus,  just  as  crystals  will  form  around  a  nucleus  of  the  same 
kind,  from  a  solution  which  would  not  otherwise  have  deposited  them,  so  will  a 
fibrinous  coagulum  often  separate  from  a  serous  fluid,  and  form  around  a  piece  of 
washed  clot  of  blood,  or  of  the  buffy  coat,  or  of  muscle  or  some  other  animal  tissue 
placed  in  it,  although  the  fluid  (such  as  that  of  hydrocele)  would  not  have 
otherwise  shown  any  disposition  to  coagulate.1  It  is  to  be  remembered,  how- 
ever, that  the  processes  of  crystallization  and  fibrillation  cannot  be  more  closely 
likened,  either  in  their  conditions  or  in  their  results ;  for  the  latter  occurs  only 
in  a  substance  which  has  been  removed  by  vital  action  from  the  category  of 
ordinary  chemical  compounds,  and  it  produces  a  distinctly  organic  form  ;  whilst 
in  crystallization  we  have  a  typical  example  of  the  exertion  of  the  purely 
physical  forces,  tending  to  produce  a  perfectly  symmetrical  and  homogeneous 
body,  whose  shape  is  characteristically  that  of  inorganic  or  mineral  substances. 
27.  The  degree  of  regularity  with  which  this  fibrillation  takes  place,  and 
the  completeness  of  the  fibres  which  are  formed  by  it,  seem  to  depend  especially 
upon  two  conditions  :  1st,  the  degree  of  previous  elaboration  to  which  the. fibrin 
has  been  subjected;  and  2d,  the  properties  of  the  surface  on  which  it  takes 
place.  Thus  we  find  the  coagulum  of  some  specimens  of  blood  to  be  much 
firmer,  and  its  fibrous  structure  to  be  more  distinct,  than  that  of  others ;  the  fibril- 
lation of  the  fibrinous  fluid  of  inflammatory  blood  is  usually  more  complete  than 
that  of  ordinary  blood;  and  that  of  the  fluid  of  plastic  exudations,  formerly 
known  as  "coagulable  lymph/'  is  still  more  distinct.  But  further,  the  fibrilla- 
tion takes  place  far  more  perfectly  when  the  fibrinous  fluid  is  effused  on  a  living 
surface,  than  when  it  is  spread  out  over  dead  matter;  and  thus  it  happens  that 
fibrinous  effusions  are  much  more  completely  converted  into  fibrous  tissue  within 
the  living  body,  and  in  immediate  contact  with  living  tissue,  than  they  ever  are 
when  removed  from  it.  A  marked  difference  may  be  observed  in  this  respect, 
between  the  superficial  and  the  central  portions  of  a  blood-clot  which  has  been 
effused  in  the  substance  of  the  living  solids ;  for  it  is  always  in  the  former  that 
the  organizing  process  is  most  advanced,  a  firm  and  distinct  fibrous  membrane 
being  often  found  on  the  exterior  of  such  clots,  whilst  their  interior  is  soft  and 
amorphous.3  Generally  speaking,  the 

fibrillation   is    more   perfect,    the   more  Fig.  2. 

slowly  it  takes  place ;  and  the  higher  the 
previous  vitalization  of  the  fibrin,  the 
longer  is  it  before  it  changes  its  state. 
Thus  the  coagulation  of  sthenic  inflam- 
matory blood,  which  produces  a  clot  of 
remarkable  firmness,  is  much  longer  in 
taking  place  than  the  coagulation  of  ordi- 
nary blood;  whilst  the  coagulation  of  the 
blood  of  cachectic  subjects,  which  takes 
place  very  rapidly,  is  feeble  and  imper- 
fect. The  plastic  effusions  .poured  out 
from  the  blood  in  these  two  opposite 
conditions,  partake  of  the  character  of  ,,., 

xu     vi      j    -x     ix-     xi.  e  xi.      •    a  Fibrous  structure  of  inflammatory  exudation 

the  blood  itself ;  those  of  the  mflamma-  from  peritoneum. 

tory  blood  of  a  previously  healthy  subject 

being  converted  into  fibrous  membranes  of  considerable  firmness  (Fig.  2),  which 

^  !  Such  appears  to  the  Author  to  be  the  true  view  of  the  results  of  the  interesting  expe- 
riments of  Prof.  Buchanan  of  Glasgow;  for  an  account  of  which  see  the  "  Proceedings  of 
the  Glasgow  Philosophical  Society"  for  1845,  and  the  "Medical  Gazette"  for  1836  pp  52 
and  90,  and  for  1845,  p.  617,  et  seq. 

2  See  Dr.  G.  Burrows,  in  "Medical   Gazette,"  1835;    and  Mr.  Prescott  Hewett    in 
"  Medico-Chirurg.  Trans."  1845. 


62  CHEMICAL   COMPONENTS   OP   THE   HUMAN   BODY. 

are  subsequently  penetrated  by  bloodvessels,  and  become  regularly  organized 
tissues ;  whilst  those  proceeding  from  the  blood  of  cachectic  subjects  frequently 
undergo  a  certain  degree  of  organization  with  great  rapidity,  but  do  not  go  on 
to  the  same  perfection,  and  speedily  degenerate.1 

28.  One  of  the  most  remarkable  examples  of  the  consolidation  of  a  fibrinous 
exudation  into  a  regular  fibrous  tissue  (which,  however,  never  becomes  vascu- 
lar), is  afforded  by  the  membrane  adherent  to  the  interior  of  the  egg-shell  (mem- 
brana  putaminis),  and  also  by  that  which  forms  the  basis  of  the  egg-shell  itself 
(Fig.  3).     Between  the  two,  there  is  no  essential  difference ;  as  may  be  seen 
by  examining  "  an  egg  without  shell,"  as  it  is  commonly  termed  (or  rather  one 
in  which  the  shell-membrane  has  not  been  consolidated  by  the  deposition  of  cal- 
careous matter) ;  or  by  treating  the  egg-shell  with  dilute  acid,  so  as  to  remove 
the  particles  of  carbonate  of  lime,  which  are  deposited  in  the  interstices  of  the 

network.  The  place  of  the  shell  is  then  found  to 
be  occupied  by  a  membrane  of  considerable  firmness, 
closely  resembling  that  which  lines  the  shell  and  sur- 
rounds the  albumen  of  the  egg,  but  thicker  and  more 
spongy.  After  maceration  for  a  few  days,  either  of 
these  membranes  may  be  separated  into  a  number  of 
laminae;  each  of  which  (if  sufficiently  thin)  will  show 
a  beautiful  arrangement  of  reticulated  fibres.  It  is 
impossible  to  refuse  to  such  a  structure  the  designa- 
tion of  an  organized  tissue,  although  it  contains  no 
vessels,  and  must  be  found  by  the  simple  consolida- 
tion of  a  fibrinous  exudation,  poured  out  from  the 
lining  membrane  of  the  oviduct  of  the  bird,  so  as  to 
Fibrous  membrane  from  the  Egg-  invest  and  inclose  the  albuminous  exudations  which 
gheii.  have  been  previously  poured  out,  layer  by  layer, 

around  the  yolk-bag.      It  is  probably  in  the  same 

manner  that  the  Chorion  of  the  Mammiferous  animal  originates ;  since  this  is  a 
new  envelope,  formed  around  the  ovum,  during  its  passage  along  the  Fallopian 
tube.  In  the  latter,  for  an  ulterior  purpose,  vessels  are  afterwards  developed,  by 
extension  from  the  contained  ovum ;  and  by  the  nutrition  they  supply,  its  size 
is  increased,  and  changes  take  place  in  its  texture.  But  in  the  egg-membrane  of 
the  Bird,  there  is  no  need  of  vessels ;  because  no  subsequent  change  in  its  tex- 
ture is  required,  and  its  duration  is  sufficient  for  the  purpose  it  has  to  answer. 

29.  Thus,  then,  we  are  led  to  regard  the  fibrillation  of  Fibrin  as  a  process 
quite  different  from  the  coagulation  of  Albumen  or  Casein ;  and  to  consider  it 
as  an  expression  or  manifestation  of  the  vital  force  with  which  the  former  has 
been  endowed,  during  that  Assimilation  of  the  crude  material  furnished  by  the 
latter,  which  seems  to  be  the  first  step  in  its  conversion  into  living  tissue.    And 
this  view  is  confirmed  by  many  facts,  which  will  be  more  appropriately  stated 
when  the  Blood  is  under  consideration  (CHAP.  IV.),  and  which  show  that  the 
condition  of  the  Fibrin  in  that  fluid  is  intimately  related  to  the  vital  powers  of 
the  system  at  large.     When  this  fibrillation  takes  place  out  of  the  body,  it  may 
probably  be  regarded  as  the  ultimate  manifestation  of  the  vitality  of  the  Fibrin, 
which  is  expended  in  producing  it;  and  .thus  it  happens  that  the  fibrinous  coagu- 
lum  passes  into  decomposition,  without  attaining  any  higher  grade  of  develop- 
ment.    But  when  it  takes  place  in  contact  with  a  living  surface,  the  exuded 
material,  continuing  to  receive  vital  influence  from  this,  and  becoming  pene- 

1  See  especially  Mr.  Dalrymple's  Memoirs  "  On  the  rapid  organization  of  Lymph  in 
Cachexia,"  in  the  "Med.-Chir.  Trans."  vol.  xxiii.;  and  "On  the  early  organization  of 
coagula  and  mixed  fibrinous  effusions  under  certain  conditions  of  the  system,"  op.  cit 
vol.  xxvii. 


ALBUMINOUS    COMPOUNDS.  63 

trated  by  fresh  blood  conveyed  in  vessels  that  extend  themselves  into  it,  gradu- 
ally passes  into  a  state  of  more  complete  organization,  and  is  at  last  developed 
into  the  condition  of  a  living  tissue.  It  is  an  obvious  error,  therefore,  to  speak 
of  the  act  of  coagulation  as  an  indication  of  the  death  of  the  Fibrin,  since  it  is 
only  so  when  the  isolation  of  the  substance  prevents  its  vital  force,  which  has 
been  thus  expended,  from  being  renewed ;  whilst,  on  the  other  hand,  when  the 
coagulation  takes  place  under  more  favorable  circumstances,  it  is  simply  the 
transition-stage  between  the  existence  of  the  fibrin  in  the  liquid  state  and  its 
existence  as  a  part  of  the  solid  fabric,  and  must  thus  be  regarded  as  a  stage  in  its 
progress  towards  complete  organization. — We  are  scarcely  warranted,  however, 
in  hence  inferring  that  Fibrin  is  the  pabulum,  at  the  expense  of  which  all  the 
tissues  are  nourished.  A  very  marked  chemical  line  of  distinction  seems  to 
separate  the  simply  fibrous  from  the  proper  cellular  tissues,  for  the  former  are 
gelatinous  in  their  composition,  whilst  the  latter  are  albuminous;  and  it  has 
been  recently  asserted  by  Prof.  Liebig,  that  fibrin,  considered  chemically,  is  in 
some  respects  intermediate  between  these  two  classes  of  compounds.1  Further, 
it  appears  from  Mr.  Paget's  observations  on  inflammatory  effusions,3  that  the 
development  of  cells  and  the  production  of  fibres  do  not  take  place  with  equal 
readiness  in  the  same  effusion ;  but  that  the  condition  of  the  plastic  fluid  which 
is  favorable  to  the  one,  is  unfavorable  to  the  other.  It  may  be  surmised, 
then,  that  the  peculiar  vital  powers  with  which  the  fibrin  is  endowed,  give  it  a 
special  tendency  to  development  into  tissues  of  the  fibro-gelatinous  type,  which 
may  thus  be  almost  said  to  be  pre-formed  in  the  blood ;  whilst  the  tissues  of  the 
cellulo-albuminous  type  develop  themselves  at  the  expense  of  some  other  element 
of  the  blood,  possibly  the  globulin  of  the  floating  corpuscles.  But  nothing  cer- 
tain can  be  stated  on  this  subject.3 

30.  The  prolonged  action  of  boiling  water,  with  free  access  of  air,  upon  Albu- 

1  Prof.  Liebig  speaks  of  the  fibrin  of  blood  as  "perhaps  albumen  half  converted  into 
gelatin."     "Familiar  Letters,"  p.  40. 

2  See  his  "  Lectures  on  Inflammation,"  in  the  "  Medical  Gazette,"  1850,  vol.  xlv.  p. 
1012. 

3  It  might  be  thought  that  some  notice  is  here  required  of  the  hypothesis  put  forth  by  Dr. 
Zimmermann,  and  espoused  by  Mr.  Simon  and  some  other  pathologists  in  this  country,  that 
the  Fibrin  of  the  blood  is  one  of  those  elements  of  the  circulating  fluid  "  which  have  arisen 
in  it  from  its  own  decay,  or  have  reverted  to  it  from  the  waste  of  the  tissues,"  instead  of 
being,  as  represented  above,  "  that  ingredient  of  the  blood,  which,  in  the  ascending  scale 
of  development,  stands  next  for  appropriation  into  the  living  textures  of  the  body,  and 
which  represents  the  ripeness  and  perfection  and  nutritiveness  of  the  blood."     [The  fol- 
lowing are  the  arguments  by  which  Mr.  Simon  supports  this  hypothesis :    First,  I  find 
that  fibrin  is  undiminished  by  bleeding,  however  frequently  repeated  ;  nay,  that  it  often, 
or  even  usually  increases  under  this  debilitating  treatment ;  its  highest  figure  given  in 
Andral's  book  (10.2)  was  at  a  fourth  bleeding  ;  and  Scherer  found  it  as  high  as  12.7  at 
the  third  venesection  in  a  case  of  pneumonia.     I  find  that  under  many  other  circumstances 
of  exhaustion  and  weakness  and  inanition,  during  the  progress  of  starvation, 1  during  dis- 
eases essentially  anaemic,  during  violent  fatigue,  and  the  like,  its  proportion  has  been 
found  at  least  as  high,  perhaps  higher,  than  in  the  inflammatory  process.    And  as  in  these 
respects  I  find  its  proceeding  to  be  in  direct  contrast  to  that  of  the  red-globules  (which 
we  know  to  be  potential  elements  in  the  blood,  and  which  are  at  once  reduced  by  bleeding 
or  starvation)  so  also  do  I  find  a  similar  contrast  in  another  striking  particular.     Messrs. 
Andral  and  Gavarret,  in  the  course  of  their  extensive  researches  in  the  comparative  phy- 
siology of  the  blood,  ascertained  that  an  improvement  in  the  breed  of  an  animal  tended 
always  (cceteris  paribus]  to  increase  the  proportion  of  its  colored  blood-corpuscles ;  they 
found  that  the  same  improvement  tended  likewise  to  diminish  the  proportion  of  its  fibrin. 
And  I  find  further  indications  of  the  same  inverse  ratio  between  the  fibrinousness  and  the 
perfection  of  the  blood,  in  the  facts — that  there  is  little  or  no  fibrin  in  the  blood  of  the 


1  In  analyzing  the  blood  of  seventeen  healthy  horses,  Andral  and  Gavarret  found  the  maximum  of  fibrin  to 
be  5  per  1000 ;  the  minimum  to  be  3 ;  the  mean  to  be  4.  In  dealing  with  diseased  horses,  many  of  them 
meagre  and  half-starved,  Dr.  Franz  Simon  found  this  proportion  increased  to  11  or  12  per  1000.  In  one  ewe, 
particularly  of  experimental  starvation  of  a  horse,  after  four  days'  total  abstinence,  this  observer  found  that 
the  animal's  proportion  of  fibrin  had  risen  from  5  to  9. 


64  CHEMICAL   COMPONENTS   OF   THE   HUMAN   BODY. 

men  and  Fibrin,  gives  rise  to  changes  in  their  condition,  and  probably  also  in 
their  composition,  which  indicate  a  transition  towards  the  gelatinous  type. 
When  Fibrin  is  thus  treated,  two  new  substances  are  produced,  one  of  which  is 
taken  up  by  the  water,  whilst  the  other  remains  insoluble  j  the  former  is  spoken 
of  by  Mulder  as  a  tritoxide  of  protein,  and  the  latter  as  a  binoxide  ;  but  the 
propriety  of  these  designations  is  extremely  doubtful.  When  Albumen  is  thus 
treated,  only  the  (so-called)  tritoxide  is  produced ;  and  the  insoluble  residue  is 
still  albumen.  Whatever  may  be  the  real  composition  of  these  substances,  their 
presence  in  the  living  body,  and  their  artificial  production  from  the  protein- 
compounds,  give  them  an  indubitable  importance. — The  tritoxide  of  protein  is, 
like  gelatin,  readily  soluble  in  water,  and  is  insoluble  in  alcohol  and  ether ;  it 
is  precipitated  from  its  solution  by  dilute  mineral  acids,  chlorine-water,  tannic 
acid,  corrosive  sublimate,  and  most  of  the  salts  of  the  metallic  oxides  ]  but  it  is 
not  thrown  down  by  dilute  acetic  acid,  by  neutral  alkaline  salts,  nor  by  that 
very  delicate  test  for  the  ordinary  protein-compounds  (§  18),  ferrocyanide  of 
potassium.  When  dried,  it  is  easily  pulverizable  ;  but  when  moist,  it  is  tough, 
viscid,  and  capable  of  being  drawn  out  in  threads ;  and  when  warmed,  it  has 
an  odor  resembling  that  of  gelatin.  It  is  probable  that  a  small  quantity  of  this 
substance  always  exists  among  the  "  extractive  matters"  of  the  Blood ;  but  it 
maybe  obtained  in  considerable  amount  from  the  "  buffy  coat"  of  inflammatory 
blood ;  and  when  its  presence  was  first  detected  there,  it  was  mistaken  for 
gelatin,  so  similar  are  its  properties.  According  to  Mulder,  it  is  chemically 
identical  with  the  substance  termed  pyin,  which  was  discovered  by  Griiterbock  in 
pus ;  and  it  is  a  very  significant  fact,  that  the  basis  of  false  membranes,  and 
that  of  the  skin  of  the  foetus,  both  of  them  being  fibrous  tissues  in  an  incipient 
grade  of  formation,  have  been  considered  to  bear  a  closer  resemblance  to  pyin 
than  to  any  other  organic  compound.  It  may  be  anticipated,  then,  that  more 
accurate  investigations  in  regard  to  the  composition  and  physiological  relations 
of  this  substance,  may  help  to  bridge  over  the  hiatus  which  at  present  exists 

foetus,  none  in  the  egg,  none  in  the  chyme,  and  less  in  the  blood  of  the  carnivora  (who 
feed  on  it)  than  in  that  of  the  herbivora. 

Some  of  these  facts,  derived  from  very  different  sources,  appear  quite  inexplicable  on 
the  theory  that  fibrin  is  essential  to  the  progressive  development  of  the  tissues ;  and  the 
opposite  inference  seems  unavoidable,  that  it  must  be  considered  an  excrementitious  pro- 
duct, derived  from  the  waste  of  the  tissues  or  the  oxidation  of  the  blood,  and  in  progress 
of  elimination  from  the  system.  This  conclusion,  carried  into  the  domain  of  pathology, 
would  lead  us  to  suppose  that  an  augmented  proportion  of  fibrin  in  the  blood  (whether 
occurring  in  active  disease,  or  within  the  limits  of  apparent  health)  can  be  taken  as  an 
indication  only  of  increased  labor  and  waste  in  certain  elements  of  the  body,  not  of  an 
increased  development  in  the  resources  and  nutrition  of  the  blood.  And  on  the  same 
grounds  it  would  appear  that  a  super-fibrination  of  the  blood,  in  acute  inflammatory  dis- 
eases, must  be  regarded  as  a  consequence  and  effect  of  those  diseases,  not  as  their  cause, 
and  not  as  a  primary  affection. ' — ED.]  This  doctrine  seems  to  the  Author  to  be  completely 
opposed  by  the  whole  physiological  history  of  Fibrin,  and  more  particularly  by  the  gradual 
development  of  this  ingredient  in  chyle,  during  its  onward  progress  towards  the  sangui- 
ferous  system ;  whilst,  again,  it  seems  to  be  entirely  negatived  by  a  comparison  of  the 
condition  of  fibrin  with  that  of  the  known  products  of  the  disintegration  of  the  tissues, 
such  as  urea  or  creatin,  in  which  we  see  a  marked  tendency  to  the  reproduction  of  purely 
physical  and  chemical  conditions  (and  this  pre-eminently  in  their  crystalline  aggregation), 
to  the  exclusion  of  those  of  vitality.  We  shall  see  that  these  last,  although  we  know  that 
they  must  be  continually  passing  through  the  blood,  are  eliminated  from  it  with  such 
jealous  care,  that,  in  the  healthy  state,  they  scarcely  accumulate  in  sufficient  amount  to 
be  detectable  ;  it  is  scarcely  conceivable,  therefore,  that  fibrin,  if  a  product  of  disintegra- 
tion, on  its  way  out  of  the  system,  should  accumulate  in  the  blood  to  the  extent  of 
between  2  and  3  parts  in  1000. — For  an  examination  of  the  objections  brought  by  Mr. 
Simon  against  the  commonly-received  view,  the  reader  is  referred  to  the  "  Brit,  and  For. 
Med.-Chir.  Rev."  vol.  vii.  p.  478. 


Simon's  "Lectures  on  General  Pathology,"  pp.  44-45,  Am.  Ed. 


ALBUMINOUS   COMPOUNDS.  65 

between  the  albuminous  and  gelatinous  compounds. — The  undissolved  residue 
left  when  fibrin  has  been  boiled  for  some  time,  to  which  the  name  of  binoxide 
of  protein  has  been  given,  is  soluble  in  dilute  acetic,  hydrochloric,  nitric  and 
sulphuric  acids,  and  also  in  potash  and  ammonia,  and  it  is  precipitated  from  its 
acid  solutions  by  ferrocyanide  of  potassium  and  acetate  of  lead  ;  in  these  re- 
spects, therefore,  agreeing  with  the  protein-compounds.  This  substance  also 
seems  to  exist  in  the  buffy  coat  of  the  blood,  and  perhaps  too  in  healthy  blood ; 
but  the  chief  interest  attaching  to  it  arises  from  the  fact,  that  a  substance  appa- 
rently identical  may  be  obtained  from  Hair,  by  dissolving  this  in  potash,  adding 
a  little  acetic  acid  to  throw  down  the  protein,  and  then  adding  a  larger  quantity  of 
the  acid,  which  throws  down  the  binoxide  of  protein  as  a  bright  yellow  precipitate. 
31.  Although  differing  considerably  from  the  protein-compounds  in  its  che- 
mical constitution,  the  Hsematin,  which  forms  the  coloring  portion  of  the  con- 
tents of  the  red  corpuscles  of  the  blood,  will  be  here  most  appropriately  noticed ; 
being  obviously  a  derivative  from  albumen,  and  being  not  improbably  in  progress 
of  preparation  to  bear  a  part  in  the  composition  of  higher  tissues.  Hsematin  is 
so  intimately  united  with  the  Globulin  of  the  red  corpuscles  (§  23),  that  the 
two  substances  can  only  be  separated  after  their  solidification;  what  is  said  of 
its  properties,  therefore,  refers  only  to  its  coagulated  state.  It  constitutes,  when 
dried,  a  dark  brown,  slightly  lustrous  mass,  which  is  devoid  of  taste  and  smell, 
and  is  insoluble  in  water,  alcohol,  and  ether ;  it  is  readily  dissolved,  however, 
by  weak  alcohol  to  which  sulphuric  or  hydrochloric  acid  has  been  added,  and 
forms  a  brown  solution,  which,  on  saturation  with  an  alkali,  yields  a  blood-red 
color.  Water  acidulated  with  the  same  acids,  exerts  no  solvent  power  on  hae- 
matin ;  but  very  dilute  solutions  of  the  caustic  alkalies  or  their  carbonates, 
either  in  water  or  in  alcohol,  dissolve  hsematin  in  almost  every  proportion.  In 
ultimate  composition,  Haematin  departs  widely  from  either  the  albuminous  or 
the  gelatinous  type,  and  is  remarkable  for  containing  a  considerable  proportion 
of  iron ;  as  is  seen  Vy  the  following  statement  founded  upon  Mulder's  analyses  : — 

Carbon.         -        .    '    ,.    '    .   ?''".  '  _  V. "'"' "'»'  :^'/;  V    '"",     ,    .  65.3 

Hydrogen       .      -  . '''•' '•' 5.4 

Nitrogen        .    ;'SV  "•* '.         .         .         .         .         .         .         .  10.4 

Oxygen        ,..  v'?!^ H-9 

Iron 7.0 

100.0 

Much  controversy  has  taken  place  regarding  the  condition  in  which  the  Iron 
exists  in  Hsematin ;  and  the  question  cannot  be  regarded  as  yet  satisfactorily 
determined.  This  much,  however,  is  certain;  that  the  red  color  is  not  due,  as 
has  been  commonly  supposed,  to  the  presence  of  iron ;  since  it  has  been  clearly 
shown  by  Scherer,  Sanson,  and  Mulder,  that  the  iron  may  be  abstracted  from 
this  red  pigment,  by  the  agency  of  acids,  without  in  the  least  degree  affecting 
its  color. — Of  the  mode  in  which  Haematin  is  generated,  and  of  its  office  in  the 
animal  economy,  we  are  at  present  completely  ignorant.  It  would  appear  to 
be  formed  by  the  agency  of  the  blood-cells,  at  the  expense  of  the  components 
of  the  fluid  in  which  they  float ;  and  it  is  considered  probable  by  Lehmann,  that 
in  this  metamorphosis  fatty  matter  takes  an  essential  part.  Hsematin  does  not 
present  itself  normally  anywhere  else  than  in  the  red  corpuscles;  and  although 
there  appears  some  reason  to  believe  that  these  are  specially  connected  with  the 
activity  of  the  respiratory  process  (§  147),  yet  no  direct  evidence  has  yet  been 
obtained  as  to  the  mode  in  which  they  minister  to  it.1  The  color  of  muscular 

1  It  may,  however,  be  said  with  almost  positive  certainty,  that  the  notion  put  forth  by 
Prof.  Liebig — that  it  is  the  iron  of  the  blood-cells  which  serves  as  the  carrier  of  oxygen 
5 


66  CHEMICAL   COMPONENTS    OF   THE    HUMAN   BODY. 

tissue  seems  to  be  dependent,  not  merely  upon  the  blood  which  circulates  through 
it,  but  also  upon  the  contents  of  its  tubular  fibres ;  so  also  does  the  hue  of  the 
vesicular  element  of  nervous  tissue  depend  partly  upon  the  pigmentary  matter 
contained  within  its  cells.  Tt  does  not  seem,  then,  to  be  an  unreasonable  sur- 
mise, that  the  hsematin  of  the  blood-corpuscles  is  a  substance  which  is  being 
prepared  by  them  for  the  nutrition  of  these  tissues;  and  this  idea  is  confirmed 
by  the  special  relation  which  seems  to  exist  between  the  presence  of  a  large 
proportion  of  corpuscles  in  the  blood,  and  the  nervo-muscular  power  of  the 
animal  (§  147). — Nearly  allied  to  haematin  is  a  substance  to  which  the  term 
Haematoidin  has  been  given,  and  which  may  be  regarded  with  probability  as 
haematin  in  a  state  of  retrograde  metamorphosis.  This  is  found  in  sanguineous 
effusions,  such  as  those  in  the  substance  of  the  brain  or  skin,  or  those  produced 
by  the  bursting  of  the  Graafian  follicles  for  the  extrusion  of  the  ova;  and  it 
presents  itself  most  characteristically  in  the  form  of  rhombohedric  crystals,  of 
a  yellowish-red  or  ruby  color,  although  it  frequently  occurs  in  the  amorphous 
condition  of  granules  and  irregular  masses.  This  substance  has  not  yet  been 
obtained  in  a  state  sufficiently  pure,  and  in  a  quantity  large  enough,  to  admit  of 
its  being  subjected  to  a  rigid  examination ;  but  it  has  been  ascertained  to  be  in- 
soluble in  alkalies,  and  to  behave  differently  from  haematin  with  other  reagents. 
Haematoidin  has  been  inferred  by  Virchow,  from  his  recent  investigations,1  to 
be  a  compound  of  haematin  and  some  protein  substance,  the  latter  probably 
forming  the  crystalline,  and  the  former  the  coloring  portion  of  the  compound ; 
and  this  seems  the  more  likely,  since  Reichert  has  found  an  albuminous  sub- 
stance, in  the  form  of  tetrahedral  crystals,  in  extra vasated  blood.  It  seems 
probable,  further,  that  haematoidin  is  a  stage  of  transition  between  the  blood- 
pigment  and  the  coloring  matters  of  the  bile,  namely,  cholepyrrhin  and  biliful- 
vin  (§  70). 

2.  Gelatinous  Compounds. 

32.  A  large  proportion,  perhaps  not  less  than  half,  of  the  tissues  of  the  body 
of  Man,  as  of  that  of  the  higher  animals  generally,  is  composed  of  a  substance, 
which,  when  these  tissues  are  acted  on  by  boiling  water,  dissolves  in  it,  and 
forms  a  jelly  on  cooling.     Some  tissues  dissolve  readily  in  this  manner,  and 
leave  scarcely  any  residue;  whilst  others  require  a  longer  coction,  and  a  larger 
proportion  of  insoluble  matter  remains.     The  substance   thus  obtained  from 
bones,  cartilages,  tendons,  ligaments,  skin,  mucous  and  serous  membranes,  &c. 
is  known  under  the  generic  appellation  of  Gelatin;  there  are,  however,  two 
forms  of  it,  one  of  which  is  distinguished  as  glutin  or  gelatin-proper,  whilst  the 
other  is  known  as  chondrin.     Although  differing  in  their  ultimate  composition 
and  in  their  behavior  with  reagents,  these  two  substances  agree  in  certain  cha- 
racteristic peculiarities,  by  which  they  are  distinguished  from  the  protein-com- 
pounds.   These  are — their  sparing  solubility  in  cold  water,  the  contact  of  which, 
however,  makes  them  swell  up  and  soften;  their  ready  solubility  in  hot  water, 
with  the  formation  of  a  jelly  as  the  solution  cools,  this  being  more  or  less  stiff 
according  to  the  source  from  which  the  Gelatin  has  been  obtained,  and  the  pro- 
portion of  it  which  has  been  dissolved;  and  the  readiness  with  which  both  forms 
are  thrown  down  by  tannic  acid  and  chlorine-water,  whilst  they  are  unaffected 
by  ferrocyanide  of  potassium. 

33.  Glutin  is  the  form  of  gelatin  which  is  yielded  on  boiling  by  the  White 

from  the  lungs  to  the  tissues  (being  then  in  the  state  of  peroxide),  and  of  carbonic  acid 
from  the  tissues  to  the  lungs  (being  then  in  the  state  of  carbonate  of  the  protoxide) — is 
not  now  held  by  any  chemist  of  repute,  and  ought  to  be  entirely  abandoned. 
1  See  "Ann.  der  Chem.  und  Pharm.,"  band  Ixxviii.  p.  353. 


GELATINOUS    COMPOUNDS.  67 

Fibrous  tissue  wherever  it  occurs,  and  by  the  animal  basis  of  Bone,  which  is 
nearly  identical  with  this.  It  gelatinizes  so  strongly,  that  1  part  of  it  in 
100  of  water  forms  a  consistent  jelly  on  cooling.  Its  reaction  with  tannic 
acid  is  so  distinct,  that  the  white  cheesy  precipitate  which  this  reagent  forms,  is 
visible  in  a  solution  of  1  part  of  glutin  in  5000  of  water.  This,  however,  is 
the  only  acid  which  throws  down  glutin  from  its  aqueous  solution ;  and  alkalies 
have  no  other  effect  than  that  of  precipitating  a  little  bone-earth.  Creosote 
gives  the  solution  a  milky  turbidity;  but  the  only  earthy  and  metallic  salts 
which  precipitate  it  are  corrosive  sublimate,  bichloride  of  platinum,  and  sul- 
phate of  binoxide  of  platinum.  In  this  respect,  as  we  shall  presently  see,  glutin 
differs  markedly  from  chondrin.  If  the  solution  of  glutin  in  hot  water  be 
boiled  for  some  time,  it  loses  the  property  of  gelatinizing,  and  at  the  same  time 
phosphate  of  lime  is  separated  from  it  (Liebig's  "Familiar  Letters/7  p.  387, 
note) ;  and  a  similar  effect  is  produced  by  repeatedly  dissolving  glutin  in  hot 
water  with  exposure  to  air.  Putrefaction  takes  place  more  readily  in  glutin 
than  in  fibrin  under  similar  circumstances;  and  according  to  Gannal,  the 
gelatigenous  tissues  are  the  first  of  the  solid  animal  structures  to  become 
putrid. — Glutin  does  not  seem  to  include  phosphorus  as  one  of  its  necessary 
components;  and  the  quantity  of  sulphur  which  it  contains  (about  0.50  per 
cent.,  according  to  Prof.  Liebig)  is  much  smaller  than  that  which  enters  into 
the  composition  of  the  Albuminous  substances.  But  it  appears  to  form  definite 
chemical  combinations  with  phosphate  and  carbonate  of  lime,  since  in  the  sub- 
stance not  merely  of  normal  osseous  tissue,  but  of  the  abnormal  ossifications  of 
fibrous  membranes,  &c.  no  such  Jicterogeneousness  is  seen,  as  would  be  produced 
by  a  mere  interstitial  admixture  of  the  organic  and  earthy  matters.  The  latter 
are  easily  separated,  however,  by  the  action  of  dilute  acids. — When  Glutin  is 
boiled  for  some  time  in  caustic  potash,  it  is  decomposed,  with  escape  of  ammonia; 
and  two  new  compounds,  leucine  and  glycine  are  produced.  The  formation  of 
the  first  of  these  is  of  peculiar  interest;  since,  as  the  same  substance  is  obtain- 
able by  the  same  agency  from  the  protein-compounds  (§  19),  a  certain  similarity 
in  the  arrangement  of  the  ultimate  elements  of  these  two  bodies  is  indicated, 
notwithstanding  their  differences  in  composition  and  characters.  Glycine  (or 
gelatin-sugar)  is  an  organic  base  of  much  interest  in  its  relations  to  certain 
excretory  substances,  as  the  hippuric  acid  of  the  urine,  and  the  glycocholic  acid 
of  the  bile  (§§  58,  68) ;  it  has  a  strong  sweet  taste,  and  is  very  soluble  in  water, 
from  which  it  may  be  crystallized  like  ordinary  sugar;  and  its  composition  is 
comparatively  simple,  its  formula  being  4  Carbon,  4  Hydrogen,  1  Nitrogen, 
3  Oxygen. 

34.  The  general  properties  of  Chondrin  are  very  similar  to  those  of  Glutin ; 
but  it  is  obtainable  only  from  Cartilages,  and  this  after  very  prolonged  boiling ; 
and  it  differs  from  glutin  in  being  precipitated  by  certain  reagents,  which  have 
no  effect  upon  the  latter.  Thus,  most  acids  throw  down  a  precipitate  from  a 
solution  of  chondrin,  though  this  may  escape  notice  on  account  of  the  facility 
with  which  it  redissolves  in  a  slight  excess  of  the  acid ;  a  considerable  precipi- 
tate, however,  is  thrown  down  by  acetic  acid,  which  is  not  redissolved  by  any 
excess  or  even  by  concentrated  acid.  Chondrin  is  also  precipitated  by  a  num- 
ber of  metallic  and  other  salts,  which  have  no  such  effect  on  glutin  ;  among  the 
most  important  of  these  are  alum,  the  sulphates  of  the  protoxide  and  peroxide 
of  iron,  sulphate  of  copper,  acetate  of  lead,  and  the  nitrates  of  silver  and  of  the 
suboxide  of  mercury. — The  comparative  elementary  composition  of  these  two 
substances  is  shown  in  the  following  table  ;  from  which  it  appears  that,  the 
proportions  of  carbon  and  hydrogen  being  nearly  the  same  in  both,  glutin  con- 
tains much  more  nitrogen  and  less  oxygen  than  chondrin. 


68  CHEMICAL   COMPONENTS   OF   THE   HUMAN   BODY. 

GMJTIN.  CHONDRIN. 

Mulder.  Scherer.  Mulder.  Scherer. 

Carbon          .         .         .         50.4  50.8  50.0  50.7 

Hydrogen     ...  6.7  7.1  6.6  6.9 

Nitrogen       .         .         .         18.3  18.3  14.4  14.7 

^Yi611  1  24.6  23.8  29.0  27.7 

Sulphur  / 

100.0          100.0  '  100.0  100.0 

35.  It  is  remarkable  that,  notwithstanding  the  very  large  proportion  of  the 
entire  mass  of  the  body,  which  is  formed  by  the  Gelatigenous  tissues,  no  Gelatin 
should  be  detectable  either  in  the  Blood,  or  in  any  of  the  healthy  fluids ;  and 
this  fact  seems  to  indicate  that  the  transformation  of  protein-compounds  into 
gelatin,  which  must  take  place  wherever  the  food  does  not  contain  that  substance 
(as  in  the  case  of  herbivorous  animals  and  of  the  embryo  within  the  egg),  is 
effected  in  the  very  act  of  their  conversion  into  fibrous  tissue — a  view  which 
appears  to  derive  probability  from  the  various  facts  already  stated  respecting  the 
properties  of  Fibrin  (§§  25,  27).     If  this  be  true,  it  seems  highly  improbable 
that  the  gelatigenous  tissues  are  ever  produced  in  any  other  way,  or  that  gelatin 
employed  as  food  can  ever  acquire  even  the  low  degree  of  organization  which 
they  exhibit;  and  reasons  will  be  hereafter  given  for  the  belief,  that  this  sub- 
stance cannot  be  truly  regarded  as  a  histogenetic  material,  but  must  be  looked 
upon  merely  as  a  pabulum  for  the  combustive  process  (see  CHAP.  vn.). — Some 
Chemists,  indeed,  maintain,  that  Gelatin  is  rather  a  product  of  the  operation 
practised  to  separate  it,  than  a  real  constituent  of  the  living  solids ;  but  this 
idea  is  inconsistent  with  several  important  facts.    Thus,  the  gelatigenous  tissues 
will  exhibit,  without  any  preparation,  the  best-marked  of  the  chemical  properties 
by  which  Gelatin  is  characterized — that  of  forming  an  insoluble  compound  with 
tannic  acid ;  and  the  tanno-gelatin,  which  may  be  obtained  by  precipitating  gela- 
tin from  its  solution,  appears  to  be  identical  with  that  which  results  from  the 
action  of  tannin  on  animal  membrane,  in  every  respect  save  the  want  of  its 
organic  structure.     A  similar  precipitate  is  thrown  down,  as  Dr.  Alfred  Taylor 
has  recently  shown,  by  adding  tannic  acid  to  the  solution  obtained  by  acting  on 
Skin  with  acetic  or  oxalic  acid.     And  further,  the  composition  of  gelatin,  and 
that  of  the  gelatigenous  tissues  (allowance  being  made  for  the  presence  of  other 
ingredients  in  the  latter),  are  found  by  ultimate  analysis  to  be  identical. — The 
fact  appears  to  be  that  there  is  somewhat  of  the  same  difference  between  gelatin, 
chemically  considered,  and  the  fibrous  tissues,  bone,  &c.  from  which  it  is  ex- 
tracted, that  exists  between  albumen  and  muscular  fibre  (§  21);  chemically 
they  are  identical,  but  the  molecular  arrangement  of  the  particles  has  been 
altered  by  organization,  so  that  the  operation  of  solvents  is  required  to  bring 
back  the  organic  compounds  to  their  original  structureless  condition.     And  this 
view  harmonizes  well  with  the  fact,  that  the  tissues  which  are  most  readily  dis- 
solved by  hot  water,  and  on  which  cold  water  has  the  most  action  (such  as  those 
of  the  air-bladder  of  the  fish),  are  those  which  have  the  least  definite  organic 
structure;  whilst,  on  the  other  hand,  those  of  which  the  fibrous  structure  is 
most  complete,  require  the  most  prolonged  action  of  hot  water  to  gelatinize  them. 
There  is  a  difference,  too,  in  the  characters  of  the  gelatin  obtained  from  these 
different  sources ;  for  that  which  is  so  readily  yielded  by  the  fish's  air-bladder, 
and  is  known  as  "isinglass,"  never  forms  a  strong  glue,  even  when  quite  dry  ; 
so  also  the  gelatin  of  the  skin  of  young  animals,  which  forms  "  size/'  though 
setting  more  firmly  than  isinglass,  cannot  be  advantageously  employed  by  the 
carpenter ;  his  hard  "  glue"  being  all  obtained  from  the  skin,  bones,  &c.  of 
adults.     These  differences  have  been  imputed  by  Dr.  Prout  to  diversities  in  the 
quantity  of  water  held  in  combination  by  the  gelatin. — The  extreme  difficulty 


OLEAGINOUS   COMPOUNDS.  b9 

which  attends  the  first  solution  of  Chondrin  cannot,  however,  be  thus  explained ; 
and  must  be  imputed  to  some  peculiarity  in  the  molecular  aggregation  of  the 
substance,  which  does  not  manifest  itself  in  a  fibrous  arrangement. — It  is  inte- 
resting to  remark  that,  of  all  the  gelatigenous  tissues,  there  is  not  one  which  can 
be  said  to  have  other  than  mechanical  functions,  such  as  that  of  binding  parts 
together,  resisting  tension,  or  antagonizing  pressure.  On  the  other  hand,  all 
the  proper  vital  functions  of  the  body  are  performed  by  tissues  whose  composi- 
tion is  albuminous. 

3.    Oleaginous  Compounds. 

36.  We  now  arrive  at  the  non-azotized  division  of  the  organic  compounds 
entering  into  the  composition  of  the  animal  fabric;  and  the  first  group  to  be 
noticed,  as  connecting  the  histogenetic  substances  with  the  mere  combustive 
materials,  is  that  of  the  Oleaginous  or  Fatty  matters.     These  are  pre-eminently 
remarkable  for  the  small  amount  of  oxygen  which  enters  into  their  composition, 
and  for  containing  carbon  and  hydrogen  in  nearly  equivalent  proportions;  they 
are  soluble  in  ether  and  hot  alcohol ;  but  they  are  insoluble  in  cold  alcohol  and 
in  water.     Fatty  substances  are  ranked  as  saponifiable  or  non-saponifiable, 
according  as  they  are  or  are  not  decomposed  by  strong  bases,  such  as  alkalies 
or  the  oxide  of  lead.     When  this  decomposition  takes  place,  the  fatty  matter  is 
separated  into  two  constituents ;  an  acid,  which  unites  with  the  stronger  base  to 
form  a  soap  or  a  plaster;  and  a  weak  base,  which  is  set  free.    How  far  this  acid 
and  base  have  a  separate  existence  previously  to  the  act  of  saponification,  or  are 
formed  in  the  process  itself,  cannot  at  present  be  positively  stated.     It  is  a  re- 
markable fact,  however,  that  the  separation  of  the  fatty  acids  from  their  base 
may  be  effected  also  by  the  agency  of  putrescent  albuminous  matters ;  and  this 
has  been  shown  by  Lehmann  to  occur  during  the  fermentation  of  milk. 

37.  The  fatty  substances  which  present  themselves  most  largely  in  the  Human 
body,  are  Margarin  and  Olein ;  the  former  of  these  being  solid  when  separate, 
but  being  dissolved  in  the  latter  (which  retains  its  fluidity  when  cooled  down 
below  0°  Fahr.)  at  the  ordinary  temperature  of  the  body.     In  the  fat  of  most 
other  animals,  the  Margarin  is  replaced  by  Stearin;  and  these  two  substances, 
as  will  be  presently  shown,  have  very  close  chemical  relations. — Margarin 
exists  in  small  quantity,  along  with  stearin,  in  most  animal  fats;  and  it  is  the 
principal  solid  constituent  of  the  vegetable  fats,  with  which,  therefore,  Human 
fat  more  closely  corresponds  than  does  that  of  most  other  animals.    It  is  a  white, 
solid,  spermaceti-like  substance,  which  melts  at  118°,  and  which  crystallizes 
from  its  solution  in  hot  alcohol  as  a  flocculent  white  powder,  that  is  found  by 
the  microscope  to  consist  of  very  delicate  and  often  curved  needles,  often  so 
grouped  as  to  radiate  from  a  central  nucleus,  an  appearance  not  unfrequently 
seen  within  the  cells  of  Adipose  tissue. — Stearin  is  also  a  spermaceti-like  sub- 
stance ;  but  its  melting-point  is  higher,   namely,  144° ;  and  it  separates  on 
cooling  from  its  solution  in  hot  alcohol  (which  takes  up  less  of  it  than  of  mar- 
garin)  in  snow-white  glistening  scales,  which  are  either  rhomboidal  tablets,  or 
short  rhombic  prisms. —  Olein  exists  in  small  quantity  in  the  solid  fats,  but  con- 
stitutes the  principal  part  of  the  fixed  oils;  and  the  tendency  of  these  to  solidi- 
fication by  cold  depends  upon  the  amount  of  stearin  or  margarin  which  they 
may  contain.     When  separated  from  these,  it  is  a  simple  colorless  oil,  which 
has  a  peculiar  tendency  to  become  rancid  on  exposure  to  the  air. — The  follow- 
ing results  of  the  ultimate  analyses  of  the  fat  of  different  animals,  by  Chevreul, 
will  show  the  close  correspondence  in  their  composition ;  whilst  it  also  makes 
apparent  the  very  large  proportion  of  Carbon  which  they  all  contain. 


70  CHEMICAL   COMPONENTS   OF   THE   HUMAN  BODY. 

Hog's  Lard.  Mutton  Fat.  Human  Fat. 

Carbon        ....         79.098  78.996  79.000 

Hydrogen   ....         11.146  11.700  11.416 

Oxygen       ....  9.756  9.304  9.584 


100.000  100.000  100.000 

38.  The  saponification  of  these  fatty  substances  gives  rise  to  the  production 
of  the  Margaric,  Stearic,  and  Oleic  acids,  and  of  the  base  known  as  Glycerine. — 
Margaric  acid  is  a  solid  white  substance,  destitute  of  smell  or  taste,  which 
crystallizes  from  a  hot  alcoholic  solution  in  groups  of  very  delicate  nacreous 
needles,  that  under  the  microscope  appear  interlaced  like  tufts  of  grass  j  it  melts 
at  the  temperature  of  133°;  and  when  further  heated,  it  decomposes  and  be- 
comes" inflammable.     Its  alcoholic  solution  has  a  slightly  acid  reaction  with 
litmus-paper. — Stearic  acid  closely  resembles  the  preceding;  but  it  is  less  solu- 
ble in  hot  alcohol,  so  that  when  both  are  dissolved  together,  it  is  the  first  to 
crystallize  as  the  alcohol  cools,  and  its  crystals  have  the  form  of  elongated 
lozenge-shaped  plates.     Its  melting-point  is  167°;  and  its  alcoholic  solution  has 
a  sufficiently  powerful  acid  reaction  to  dissolve  the  alkaline  carbonates. —  Oleic 
acid,  like  olein,  is  liquid  at  ordinary  temperatures,  and  is  a  limpid  oily  fluid, 
having  neither  taste  nor  smell,  and  exerting  no  action  upon  litmus.     In  this 
state,  when  freely  exposed  to  the  atmosphere,  it  absorbs  twenty  times  its  volume 
of  oxygen,  without  giving  off  carbonic  acid,  and  becomes  changed  into  a  thicker 
fluid  which  reddens  litmus;  so  that  oleic  acid  usually  exhibits  this  reaction,  un- 
less special  care  have  been  taken  to  obtain  it  in  a  state  of  purity.     When  cooled 
down  to  about  43°,  however,  oleic  acid  solidifies  into  a  hard  white  crystalline 
mass,  which  remains  unaffected  by  exposure  to  the  atmosphere.     It  is  soluble 
in  alcohol  at  ordinary  temperatures ;  but  crystallizes  out  of  this  solution  in  long 
needles,  when  it  is  exposed  to  extreme  cold. — The  following  table  of  the  atomic 
constitution  of  these  acids  will  assist  in  showing  their  mutual  relations : — 

Stearic.          Margaric.  Oleic. 

Carbon       v   * ;  > -.'* ••••  -.•.  -j •;;  *•'•. •  j\- •':..< .','     68  34  36 

Hydrogen      .*  -  '  V     mt  'i'6.-r. ,.  V-     .>        66  33  33 

Oxygen          f't      *     . 'v       ^  .,  r. ' >..,  '  .  ,        533 

Water        , ;;  : . "  t  '.  '  ,. ': .;"<^".'/ ., :.     211 

Thus  it  appears  that  Stearic  acid  is  the  equivalent  of  two  proportionals  of 
Margaric  acid,  minus  1  eq.  of  oxygen;  and  as  it  is  easy  to  convert  the  former  into 
the  latter  by  dry  distillation,  there  is  every  probability  that  stearic  acid  is  formed 
in  the  living  body  at  the  expense  of  the  margaric  acid,  which  may  be  taken  in 
as  a  constituent  of  vegetable  food.  Further,  a  relation  between  the  Margaric 
and  Oleic  acids  is  indicated  by  the  fact  that,  when  the  latter  is  exposed  to  the 
action  of  oxygen  at  an  elevated  temperature,  it  becomes  converted  into  an  acid 
whose  composition  is  represented  by  the  formula  34C,  33H,  50;  whilst  the 
former,  when  treated  with  peroxide  of  lead,  so  as  to  be  made  to  undergo  further 
oxidation,  is  converted  into  an  acid  whose  composition  is  represented  by  the 
formula  34C,  33H,  40 -f  HO;  so  that  these  two  compounds  appear  to  present 
different  grades  of  oxidation  of  one  and  the  same  radical. 

39.  The  substance  known  as  Glycerine  is  produced  in  the  act  of  saponifying 
the  ordinary  fats  of  the  body  of  man  and  of  most  other  animals ;  and  has  been 
commonly  regarded  as  the  base  with  which  the  fatty  acids  are  united  to  form 
them.     It  has  not  been  found  possible,  however,  to  reproduce  margarin,  stearin, 
or  olein,  by  combining  their  respective  acids  with  glycerine;  and  there  are 
moreover,  adequate  reasons  for  considering  that  the  real  base  of  the  fats  is  a 
compound  having  the  composition  3C,  2H,  0,  whilst  glycerine  is  formed  by 
60,  7H,  50,  and  that  two  equivalents  of  the  former  are  converted  into  one  of 


OLEAGINOUS   COMPOUNDS.  71 

the  latter  in  the  act  of  saponification,  by  the  addition  of  3  equivs.  of  water.  To 
this  hypothetical  base,  the  name  of  oxide  of  lipyl  has  been  applied. — Glycerine 
is  a  faintly  yellow  fluid,  with  an  agreeable  sweetish  taste ;  it  cannot  be  obtained 
in  a  solid  form,  but  may  be  brought  to  the  consistence  of  a  thick  syrup ;  it  dis- 
solves readily  in  water  and  alcohol,  but  not  in  ether ;  and  it  exerts  no  reaction 
on  vegetable  colors.  It  is  remarkable  for  its  solvent  powers,  which  are  scarcely 
inferior  to  those  of  water ;  and  in  particular  for  the  large  quantity  of  alkalies 
and  metallic  oxides  which  it  will  take  up.  When  heated  in  the  air,  it  becomes 
inflammable,  and  burns  with  a  blue  flame. 

40.  The  saponifiable  Fats  ordinarily  make  up  a  considerable  part  of  the  sub- 
stance of  the  Human  body,  and  are  found  in  large  amount  in  its  "nutritious 
fluids.  There  can  be  no  doubt  that  they  are  derived  from  the  fatt}T  components 
of  the  food,  when  these  exist  in  sufficient  amount;  but  there  is  also  adequate 
evidence  that  fatty  matters  may  be  generated  by  the  transformation  of  the  Sac- 
charine compounds.  The  experiments  of  Liebig,  Dumas,  Boussingault,  Persoz, 
and  others,  have  shown  that  animals  fed  upon  an  amylaceous  diet  form  more  fat 
than  this  contains  f  but  they  have  not  made  evident  either  the  place  in  which 
that  transformation  takes  place,  nor  the  mode  in  which  it  is  effected.  The  re- 
searches of  M.  Bernard,  however,  have  thrown  considerable  light  upon  this 
subject;  and  have  shown  that  the  Liver  is  probably  the  organ  by  whose  agency 
the  production  of  fat  is  accomplished.  For  he  has  ascertained  that  the  blood 
of  the  hepatic  vein  ordinarily  contains  more  fat  than  that  of  the  portal  vein ; 
and  that  the  hepatic  vein  contains  fat,  when  none  can  be  found  in  the  portal 
vein,  the  animal  having  been  previously  fed  on  substances  containing  no  fatty 
matter.  He  has  further  ascertained  that  this  production  of  fat  is  to  a  certain 
degree  vicarious  with  that  of  sugar,  to  be  presently  described  (§  46) ;  the  former 
being  characteristic  of  herbivorous,  and  the  latter  of  carnivorous  animals ;  the 
former  ceasing,  when  the  latter  is  unusually  excited  by  puncture  of  the  medulla 
oblongata ;  and  fat  deing  deficient  in  the  liver  of  diabetic  patients,  whilst  con- 
versely sugar  is  deficient  in  fatty  liver.3  But  there  are  certain  phenomena 
attending  the  degeneration  and  decay  of  Albuminous  substances,  which  seem  to 
indicate  that  Fatty  matter  may  be  generated  also  by  their  metamorphosis.  This 
probability  rests  not  only  upon  the  fact,  that  acids  of  the  butyric  acid  group 
have  been  actually  generated  during  the  decomposition  of  albumen  (§  18),  but 
also  upon  the  evidence  afforded  by  that  pathological  change  occurring  in  the 
living  body,  to  which  the  name  of  "  fatty  degeneration' '  has  been  applied,  and 
by  that  production  of  "adipocere"  in  dead  bodies  which  sometimes  takes  place 
to  a  very  remarkable  extent.  To  the  former  class  of  phenomena,  attention  has 
been  particularly  directed  by  Prof.  Rokitansky  and  by  Mr.  Paget ;  the  former 
of  whom3  enumerates  eleven  classes  of  instances  in  which  protein-compounds 
are  replaced  by  fatty  matter,  in  such  conditions  that  it  is  hardly  possible  to 
assume  anything  but  that  the  fat  is  one  of  the  products  of  spontaneous  trans- 
formation of  the  higher  compound ;  whilst  the  latter4  strengthens  this  view  by 
various  additional  considerations.  The  substance  termed  adipocere  is  nothing 
else  than  a  soap  formed  by  the  combination  of  fatty  acids  with  an  ammoniacal 
or  calcareous  base ;  and  it  may  be  generated  in  the  course  of  even  a  few  weeks 

1  See  especially  the  Memoirs  of  the  last-named  experimenters  in  the  "Ann.  de  Chim." 
Nouv.  Ser.  torn  xvi.  p.  419. 

2  See  the  Reports  of  the  Lectures  delivered  by  M.  Bernard  before  the  College  of  France, 
in  "  L'Union  Medicale"  for  1850,  Nos.  82,  et  seq. ;  and  a  very  excellent  digest  of  M.  Ber- 
nard's recent  contributions  to  Experimental  Physiology,  contained  in  the   "American 
Journal  of  the  Medical  Sciences"  for  July  and  October,  1851. 

3  "  Handbuch  der  Pathologischen  Anatomic,"  band  i.  pp.  283-90. 

4  See  Mr.  Paget' s   "Lectures  on  Nutrition,"  Lect.  v.  in  the  "Medical  Gazette"  for 
1847. 


72  CHEMICAL   COMPONENTS   OF   THE    HUMAN   BODY. 

by  macerating  a  piece  of  muscle  in  water,  as  has  been  proved  by  various  experi- 
menters.1— This  conversion  of  protein-compounds  into  fatty  matters,  however, 
must  always  be  looked  upon  as  a  pathological  change,  when  it  occurs  in  the  tis- 
sues ;  but  its  spontaneous  occurrence  must  be  admitted  as  valid  evidence,  that 
the  fat  which  is  generated  in  the  liver  may  be  formed  out  of  the  products  of  the 
disintegration  of  the  albuminous  tissues,  or  even  by  the  metamorphosis  of  the 
albuminous  elements  of  the  food.3  In  one  of  these  two  modes  it  seems  evident 
that  the  liver-fat  must  be  formed  in  Carnivorous  animals  ;  but  in  the  Herbivora 
its  materials  will  be  more  readily  furnished  by  the  saccharine  alimentary  mat- 
ters. 

41.  The  importance  of  these  Fatty  matters  in  the  Animal  economy  must  not 
be  estimated  merely  by  the  proportion  of  its  fabric  that  is  made  up  of  Adipose 
tissue,  the  cells  of  which  are  filled  with  a  mixture  of  Margarin  (in  man),  or  of 
Stearin  (in  most  other  animals),  with  Olein.  For  it  is  next  to  certain  that  the 
nutrition  of  Nervous  tissue  is  effected  in  great  degree  at  their  expense,  although 
the  precise  composition  of  that  tissue,  and  its  chemical  relations  to  the  histo- 
genetic  substances,  have  not  yet  been  elucidated.  And  we  shall  find  that  their 
presence  in  the  Chyle  and  Blood  has  probably  a  no  less  intimate  relation  to  the 
general  processes  of  Nutrition,  than  it  has  to  the  formation  of  the  tissues  of 
which  it  is  the  more  especial  pabulum.  Further,  a  considerable  proportion  of 
the  fatty  matters  introduced  into  the  nutritious  fluids  of  warm-blooded  animals, 
never  forms  part  of  their  tissues  at  all,  but  is  at  once  removed  by  a  process 
essentially  resembling  combustion,  on  which  the  maintenance  of  the  heat  of  the 
body  is  dependent. — The  amount  of  fatty  matter  in  the  Chyle  depends  in  great 
part  upon  the  nature  of  the  food,  being  larger  in  proportion  as  the  digested 
aliment  has  contained  a  greater  abundance  of  it ;  and  its  presence  is  indicated 
by  the  milky  opacity  that  distinguishes  this  fluid  from  Lymph,  to  which  in 
other  respects  it  bears  a  close  resemblance.  This  milky  opacity  is  not  so  much 
due  to  the  presence  of  the  larger  oil-globules,  which  are  distinctly  recognizable 
as  such  with  the  aid  of  the  microscope ;  as  it  is  to  the  diffusion  of  the  fatty 
matter  through  the  whole  liquid,  in  particles  of  such  extreme  minuteness  that 
their  diameter  can  be  scarcely  measured,  forming  what  has  been  termed  by  Mr. 
Gulliver  the  "molecular  base"  of  the  chyle.  The  fatty  matter  of  the  Chyle  is 
for  the  most  part  unsaponified,  and  corresponds  in  its  composition  to  that  of 
the  ordinary  salts  of  the  oxide  of  lipyl. — The  amount  of  fat  contained  in  the 

1  It  has  been  supposed  by  some,  that  the  presence  of  adipocere  is  sufficiently  accounted 
for  by  that  of  the  fat  previously  contained  in  the  muscular  substance,  and  that  the  decom- 
position of  the  proper  muscular  tissue  has  no  share  in  its  formation,  except  as  furnishing 
its  base.     This,  however,  is  an  untenable  proposition.     A  body  was  exhumed  at  Bristol 
some  years  since,  which  had  been  buried  during  the  Civil  War,  and  which  appeared  exter- 
nally in  a  state  of  remarkable  preservation,  the  flesh  retaining  much  of  the  plumpness  of 
life  ;  and  as  this  was  in  a  state  of  complete  saponification,  it  is  obvious  that  the  amount 
of  adipocere  must  have  been  far  greater  than  the  fat  previously  in  the  body  would  account 
for.     And  besides,  the  structural  form  of  the  muscular  tissue  may  be  clearly  made  out  in 
adipocere  produced  by  the  action  of  water  upon  it.     Further,  it  has  been  ascertained  by 
Blondeau  ("  Compt.  Rend."  torn.  xxv.  p.  360),  that  the  casein  of  cheese  undergoes  a  grad- 
ual transformation  into  a  saponifiable  fat ;  and  that  the  same  change  takes  place  in  fibrin 
under  similar  circumstances. — For  an  excellent  summary  of  the  evidence  upon  this  sub- 
ject, with  various  pathological  and  experimental  illustrations,  see  the  Memoir  of  Dr.  R. 
Quain  on  "Fatty  Diseases  of  the  Heart,"  in  the  "  Medico-Chirurgical  Transactions,"  vol. 
xxxiii. 

2  Certain  experiments  of  Boussingault  upon  ducks   appear  at  first  sight  to  favor  the 
idea  that  fat  may  be  formed  from  albuminous  substances  during  the  digestive  process  ; 
but,  as  has  been  pointed  out  by  Lehmann  (op.  cit.  vol.  i.  p.  258),  these  results  are  by  no 
means  sufficient  to  prove  the  existence  of  so  remarkable  a  transformation,  since  the  fatty 
matters  found  within  the  intestinal  canal,  when  the  birds  had  been  fed  on  albumen  and 
casein  containing  little  or  no  fat,  may  have  been  derived  from  the  bile. 


OLEAGINOUS   COMPOUNDS.  73 

Blood  is  more  constant,  being  comparatively  little  dependent  upon  the  supply 
directly  furnished  by  the  food ;  and  here,  therefore,  we  have  an  additional  proof 
that  the  organism  itself  possesses  the  power  of  generating  fat  from  other  mate- 
rials, so  as  to  supply  what  may  be  deficient  in  the  aliment.  In  its  normal  condi- 
tion, the  Blood  contains  from  about  1.4  to  3.3  parts  of  fat  in  1000 ;  but  this 
proportion  may  undergo  a  large  temporary  increase,  by  the  admixture  of  chyle 
peculiarly  rich  in  oily  matters.  Thus  when  blood  is  drawn  within  an  hour  or 
two  after  a  meal  including  much  fat,  particularly  if  this  had  been  preceded  by 
a  long  fast,  the  admixture  of  chyle  is  indicated  by  the  "  milkiness"  of  the  serum, 
which  is  found  on  examination  to  depend  upon  the  presence  of  the  "  molecular 
base"  of  the  chyle ;  and  the  total  proportion  of  fatty  matter  in  the  blood  then 
considerably  exceeds  the  average.  In  a  few  hours  more,  however,  the  serum 
recovers  its  usual  clearness,  and  the  excess  of  fat  in  the  blood  disappears ;  owing, 
it  may  be  reasonably  surmised,  to  its  consumption  in  the  processes  of  nutrition 
and  respiration.  The  saponifiable  fatty  matters  proper  to  the  blood  exist  in  it 
(excepting  in  the  case  just  stated)  only  in  the  saponified  condition;  this  change 
being  due  to  the  influence  of  the  fixed  alkalies  with  which  they  are  come  into 
contact.  As  already  mentioned,  they  seem  to  be  united  with  the  Fibrin  of  the 
blood  with  peculiar  intimacy,  and  they  constitute  not  less  than  3  per  cent,  of 
its  substance  ;  more  than  2  per  cent,  of  fat  may  be  obtained  from  the  dried  blood- 
corpuscles  ;  whilst  the  dry  solids  of  the  serum  do  not  contain  above  1.8  per  cent. 
— The  quantity  of  fat  in  the  Lymph  is  never  large;  and  usually  only  traces  of 
this  substance  are  found. 

42.  Next  to  the  nutrition  of  the  adipose  and  nervous  tissues,  the  most  obvi- 
ous purpose  to  which  the  Fatty  matters  of  the  chyle  and  blood  are  subservient, 
is  the  maintenance  of  Animal  Heat.  The  conditions  of  this  calorifying  process 
will  be  more  particularly  considered  hereafter  (CHAP,  xin.);  and  at  present  it 
will  be  sufficient  to  state,  that  it  seems  essentially  to  consist  in  the  union  of  the 
carbon  and  hydrogen  of  fatty  and  other  combustible  matters,  with  oxygen  intro- 
duced by  the  respiratory  process;  thus  generating  carbonic  acid  and  water, 
which  are  set  free  through  the  same  channel. — But  there  is  strong  reason  to 
believe,  that  Fatty  matter  performs  a  most  important  part  in  the  assimilation 
of  even  the  albuminous  constituents  of  the  food,  and  in  their  conversion  into 
plastic  material  in  the  first  place,  and  subsequently  into  actual  tissue.  It  has 
been  shown  by  Lehmann  and  Elsasser,  that  the  combination  of  fat  with  protein- 
compounds  renders  the  latter  much  more  easily  reducible  by  the  digestive  pro- 
cess; and  it  has  also  been  shown  by  Lehmann,  that  the  presence  of  fat  is 
necessary  to  enable  albuminous  matters  to  act  as  ferments;  whence  he  comes 
to  the  conclusion,  on  chemical  grounds  only,  that  "fat  is  one  of  the  most  active 
agents  in  the  metamorphosis  of  animal  matter."  This  view  derives  support 
from  a  large  number  of  facts  with  which  the  Physiologist  and  Pathologist  are 
familiar.  For,  as  was  first  specially  noticed  by  Ascherson,1  fat  is  always  present 
in  considerable  amount  in  newly-forming  organized  fabrics;  it  being  a  uni- 
versal constituent  of  the  nuclei  of  cells,  both  in  the  Vegetable  and  Animal 
kingdoms,  and  being  a  large  component  of  embryonic  structures  generally. 
Moreover,  as  just  now  pointed  out,  the  fat  of  the  blood  is  most  intimately  as- 
sociated, and  is  combined  in  largest  amount,  with  the  most  vitalized  constituents 
of  the  blood,  namely,  the  fibrin  and  the  corpuscles;  and  plastic  exudations 
from  the  blood  contain  much  more  true  fat  than  the  non-plastic,  although  the 
latter  may  contain  a  considerable  amount  of  cholesterin.  So,  again,  those  can- 
cerous growths  whose  increase  is  most  remarkable  for  its  rapidity,  contain  a 
large  amount  of  fat.  The  remarkable  power  which  cod-liver  oil  has  been  found 

1  See  his  Memoir  "Ueber  die  physiologische  Bedeutung  der  Fettstoffe,"  in  "Mailer's 
Archiv."  1840. 


74  CHEMICAL   COMPONENTS   OF   THE   HUMAN   BODY. 

to  possess,  of  promoting  the  nutrient  processes  in  individuals  laboring  under 
tuberculous  cachexia,  can  scarcely  be  attributed  to  anything  else  than  to  its 
furnishing  an  abundant  supply  of  fatty  matters  in  a  form  that  renders  them 
peculiarly  easy  of  assimilation.     Taking  all  these  facts  into  account,  we  seem 
justified  in  accepting  the  conclusion,  that  in  the  metamorphosis  of  the  albumi- 
nous constituents  of  the  food  into  the  organized  tissues,  of  which  they  are  the 
I  roper  pabulum,  fat  takes  an  essential  part;  and  thus  it  comes  to  have  a  much 
igher  place  in  the  economy  of  the  living  system  than  has  usually  been  assigned 
to  it.1 

43.  Of  the  non-saponifiable  fats,  or  "lipoids,"  there  are  two  which  appear  to 
be  normal  constituents  of  the  blood;  though  it  is  doubtful  whether  they  are 
ever  employed  in  the  formation  of  tissue,  and  whether  they  are  not  rather  to 
be  looked  on  as  excrementitious  products,  resulting  from  the  disintegration  of  the 
living  structure. —  Cholesterin  (or  biliary  fat),  the  most  important  of  these,  is 
a  hard  spermaceti-like  substance,  which  separates  from  its  solutions  in  nacreous 
scales  that  are  found  under  the  microscope  to  have  the  form  of  rhombic  tablets ; 
it  is  quite  insoluble  in  water,  but  is  soluble  in  ether,  and  also  in  boiling  alcohol, 
from  which,  however,  the  greater  part  separates  in  cooling;  it.  is  also  slightly 
soluble  in  soap-water,  and  more  freely  in  the  fatty  oils  and  in  taurocholic  acid. 
It  does  not  melt  until  heated  to  298°,  and  it  solidifies  again  and  becomes  per- 
fectly crystalline  at  275°.  It  is  not  decomposed  by  concentrated  alkalies,  even 
when  the  mixture  is  submitted  to  prolonged  heat.  Its  composition  is  represented 
by  the  formula  37C,  32H,  0;  but  its  combining  equivalent  is  as  yet  uncertain. 
Cholesterin  is  constantly  present  in  the  blood,  to  the  amount  of  from  .025  to  .2 
parts  in  1000  (that  is,  from  ^th  to  jth  of  one-thousandth  part  of  the  whole 
mass) ;  and  its  quantity  seems  to  be  augmented  in  old  age,  and  in  many  acute 
diseases,  as  also  in  icterus.  It  is  also  stated  to  be  a  constituent  of  the  nervous 
tissue,  having  been  extracted  from  the  brain  by  Couerbe  and,  other  experiment- 
ers; but  it  may  be  doubted  whether  it  is  not  rather  a  product  of  the  disintegra- 
tion of  nerve-substance,  which  is  destined  to  be  taken  back  into  the  blood  for 
elimination  by  the  excretory  apparatus,  like  the  kreatine  which  may  be  extracted 
from  the  juice  of  flesh  (§  60),  or  the  urea  which  is  obtainable  from  the  vitreous 
humor  of  the  eye  (§  53),  both  being  undoubtedly  excrementitious  matters. 
For  Cholesterin  is  a  characteristic  component  of  the  biliary  excretion,  and  is 
closely  related  to  its  peculiar  acids;2  so  that  it  can  scarcely  be  looked  upon  in 
any  other  light  than  as  an  excrementitious  product,  the  highest  function  of 
which  is  to  assist  in  the  support  of  the  calorifying  process.  It  is  frequently 
separated  from  the  blood  as  a  morbid  product;  thus  it  is  often  present  in  con- 
siderable quantity  in  dropsical  fluids,  and  particularly  in  the  contents  of  cysts; 
and  may  be  deposited  in  the  solid  form  in  degenerated  structures,  tubercular 
concretions,  &c. — Of  the  other  non-saponifiable  fat,  termed  Serolin,  much  less 
is  known.  It  is  obtained  from  the  serum  of  blood,  after  the  removal  of  the 
other  fats;  and  seems  to  differ  from  cholesterin  chiefly  in  having  a  lower  nielt- 

1  It  was  first  discovered  by  Ascherson,  that  when  an  oil-globule  is  surrounded  by  an 
albuminous  solution,  it  becomes  invested  by  a  pellicle  of  coagulated  albumen ;  and  he  went 
so  far  as  to  present  this  as  the  type  of  cell-formation  in  the  living  body.     In  this,  however, 
he  was  undoubtedly  in  error;  for  the  passive  coagulated  albuminous  pellicle  thus  formed 
has  nothing  in  common  with  the  activity  of  a  true  cell ;  and  it  may  be  generated,  more- 
over (as  shown  by  Mulder),  around  other  substances,  gum  arabic,  for  instance. — In  con- 
nection with  this  subject,  the  Memoir  by  Prof.  Bennett  on  "the  Structural  Relation  of 
Oil  and  Albumen  in  the  Animal  Economy,"  in  the  "Edinb.  Monthly  Journ.  of  Med.  Sci." 
vol.  viii.  p.  566,  and  his  work  on  Cod-liver  Oil,  may  be  advantageously  referred  to. 

2  By  the  action  of  oxidizing  agents  upon  Cholesterin,  a  peculiar  acid,  cholesteric  acid, 
is  obtained;  and  the  same  acid  (as  shown  by  Schlieper)  may  be  obtained  in  the  same  way 
from  the  resinous  acids  of  the  bile,  and  from  no  other  organic  substance  whatever.     (See 
Liebig's  "Familiar  Letters,"  p.  440,  note.) 


SACCHARINE   COMPOUNDS.  75 

ing-point,  97°,  and  in  separating  from  its  alcoholic  solution  in  nacreous  glisten- 
ing flocculi. 

44.  It  has  been  supposed  that  the  substance  of  the  Brain  contains  fatty  acids 
of  a  peculiar  character,  to  which  the  terms  Cerebric  and  Oleo-pJiosphoric  have 
been  given  by  Fremy.     Both  of  these  have  been  said  to  contain  a  large  quantity 
of  phosphorus,  and  the  former  to  present  the  additional  anomaly  of  a  fatty  acid 
containing  nitrogen.     It  appears  probable,  however,  that  in  the  analysis  of  Nerv- 
ous tissue  which  gave  the  latter  of  these  results,  due  care  was  not  taken  to 
separate  its  fatty  and  its  albuminous  constituents ;  and  that  the  supposed  Cere- 
bric acid  has  no  real  existence,  being  merely  an  admixture  of  albumen  with  an 
ordinary  fatty  acid.1     Still,  it  appears  that  the  fats  of  the  brain  contain  phospho- 
rus in  some  peculiar  state  of  combination,  and  similar  "  phosphorized  fats"  are 
found  in  the  blood;  and  the  belief  formerly  expressed  by  Berzelius,  that  the 
phosphorized  fats  of  the  blood  are  chiefly  contained  within  the  red  corpuscles, 
has  been  recently  confirmed  by  the  analyses  of  Lehmann,  who  has  found  in  the 
red  corpuscles  of  arterial  blood  1.8  per  cent.,  in  those  of  venous  blood  no  less 
than  3.6  per  cent,  of  fat  extractible  by  ether,  which,  when  incinerated,  yielded 
not  less  than  22  per  cent,  of  ash,  chiefly  consisting  of  acid  phosphate  of  lime. — 
In  what  state  this  phosphorus  exists,  however,  is  as  yet  uncertain.     It  will  be 
remembered  that  Prof.  Liebig  has  lately  ainrmed  very  decidedly,  that  phospho- 
rus does  not  occur,  either  in  the  nervous  tissue  or  in  any  organic  compound, 
except  in  the  condition  of  phosphoric  acid. — It  remains  to  be  seen,  therefore, 
how  far  the  fatty  matters  of  the  Nervous  tissue  are  really  peculiar  to  it,  and 
whether,  if  they  are  different  from  the  ordinary  fats,  the  latter  may  be  meta- 
morphosed into  them. 

4.   Saccharine  Compounds. 

45.  Of  the  organic  components  of  the  human  body,  it  now  only  remains  for 
us  to  consider  those  of  the  Saccharine  group,  whose  presence  in  the  nutritious 
fluids,  so  far  as  at  present  known,  serves  no  higher  purpose  than  that  of  supply- 
ing material  for  the  calorifying  process,  unless  they  can  be  indirectly  made 
available,  by  undergoing  conversion  into  fat,  as  materials  for  the  generation  of 
tissue. — The  form  of  Sugar  which  appears  to  be  normally  present  (usually,  at 
least,  if  not  constantly)  in  the  Blood,  is  that  known  as  Glucose,  or  "grape-sugar," 
which  is  the  saccharine  compound  that  is  most  commonly  present  in  fruits,  and 
that  results  from  the  transformation  of  starch  by  the  action  of  acids,  ferments, 
&c.     This  substance  differs  from  cane-sugar  both  in  composition  and  properties  j 
for  whilst  the  formula  of  crystallized  cane-sugar  is  12C,  11H,  110  (which  is 
considered  as  resulting  from  the  combination  of  120,  9H,  90,  the  equivalent 
of  anhydrous  sugar,  with  2HO),  that  of  crystallized  glucose  is  12C,  14H,  14O, 
this  also  containing  2  equivalents  of  HO  in  combination  with  the  sugar  itself. 
Glucose  is  much  less  sweet  than  cane-sugar,  is  only  half  as  soluble  in  water, 
and  is  much  less  disposed  either  to  crystallize,  or  to  enter  into  combination  with 
oxide  of  lead  and  other  substances.     It  has  less,  in  fact,  of  those  peculiar  pro- 
perties which  so  remarkably  assimilate  cane-sugar  to  inorganic  compounds.     We 
accordingly  find  that  the  relations  of  the  two  sugars  to  the  animal  economy  are 
very  different.     Cane-sugar,  when  injected  in  any  considerable  amount  into  the 
general  current  of  the  circulation,  is  neither  assimilated  nor  removed  by  the 
combustive  process ;  but,  like  soluble  salts  thus  introduced,  is  speedily  removed 
by  the  kidney,  being  discovered  in  the  urine.3     On  the  other  hand,  a  much  larger 

1  Liebig's  "  Animal  Chemistry,"  3d  edit.,  p.  257. 

2  This  has  been  shown  by  various  experimenters,  among  whom  Dr.  Percy  ("Medical 
Gazette,"  vol.  xxxii.),  Prof.  Lehmann  ("Physiological  Chemistry,"  vol.  i.  p.  298),  and 
Dr.  Cl.  Bernard  ("  Compt.  Rend."  torn.  xxii.  pp.  534-537),  may  be  particularly  mentioned. 


76  CHEMICAL   COMPONENTS    OF   THE   HUMAN   BODY. 

quantity  of  grape-sugar  may  be  injected  into  the  general  circulation,  without  any 
trace  of  it  becoming  detectable  in  the  urine  ;*  hence,  it  is  obvious  that  this  is 
applicable  to  some  purpose  within  the  system,  and  does  not  require  to  be  cast 
out  as  a  foreign  substance.  The  presence  of  Glucose  in  the  Chyle  and  Blood 
appears  to  depend  upon  the  presence  of  either  starch  or  sugar  in  the  food.  The 
transformation  of  starch  into  glucose  is  effected,  as  will  hereafter  be  seen,  during 
the  passage  of  the  alimentary  matter  along  nearly  the  whole  length  of  the  canal ; 
this  conversion  being  begun  by  the  saliva,  and  continued  by  the  pancreatic  and 
other  secretions  which  are  poured  into  the  intestinal  tube.  That  the  glucose 
thus  formed  is  partly  taken  up  by  the  lacteals,  appears  from  the  experiments  of 
Trommer  and  Lehmann;3  but  that  it  is  also  more  directly  absorbed  into  the 
blood-vessels,  like  other  soluble  matters,  by  simple  endosmose,  has  been  deter- 
mined by  M.  Cl.  Bernard,3  who  has  always  met  with  distinct  traces  of  cane-sugar 
in  the  blood  of  the  vena  portse  of  animals  that  have  been  fed  upon  it ;  and  there 
appears  to  be  a  special  provision  in  the  liver  for  the  conversion  of  the  sugar  thus 
absorbed,  into  the  form  in  which  its  presence  in  the  blood  can  be  best  tolerated 
until  it  is  eliminated  by  the  respiratory  process.  For  it  appears  from  the  expe- 
riments of  M.  Bernard  (loc.  cit.)  that,  although  cane-sugar  is  rapidly  eliminated 
by  the  kidneys  when  it  is  injected  into  the  general  circulation,  it  may  be  injected 
in  considerable  amount  into  the  portal  system,  without  producing  any  such  ef- 
fect. When  large  quantities  of  saccharine  or  of  amylaceous  matters  have  been 
employed  as  food,  the  general  mass  of  the  blood  is  found  to  contain  an  apprecia- 
ble portion  of  sugar,  as  has  been  shown  some  time  since  by  Prof.  R.  Thompson,4 
and  M.  Magendie.5  But  it  has  been  recently  shown  by  M.  Bernard,  that  a  sugar 
nearly  allied  to  glucose  is  a  constant  constituent  of  the  blood  drawn  from  the 
hepatic  vein,  ascending  cava,  right  auricle,  and  pulmonary  artery  of  all  animals, 
whether  they  have  been  fed  upon  amylaceous  or  saccharine  substances,  or  upon 
food  entirely  destitute  of  these  principles ; — a  fact  of  the  highest  interest,  of 
which  the  explanation  will  presently  appear. 

46.  From  the  readiness  with  which  Glucose  undergoes  transformation  into 
lactic  acid,  in  the  presence  of  azotized  compounds,  there  can  be  little  doubt  that 
this  change  is  continually  taking  place  in  the  living  body ;  and  it  is  probably  in 
the  form  of  lactic  acid,  that  glucose  is  rendered  subservient  to  the  maintenance 
of  animal  heat  by  the  combustive  process.  Such,  therefore,  we  may  consider  to 
be  the  usual  destination  of  the  Saccharine  compounds  introduced  as  food.  But, 
as  already  mentioned,  there  is  ample  evidence  that,  when  there  is  a  deficiency 
of  fatty  matters  in  the  food,  these  may  be  formed  by  a  metamorphosis  of  its  sac- 
charine constituents ;  and  with  this  change,  there  is  a  strong  probability  that 
the  Liver  is  chiefly  concerned.  But  further,  evidence  has  been  recently  obtained, 
that  this  important  organ  can  actually  generate  Sugar  from  other  than  amyla- 
ceous compounds ;  for  it  has  been  ascertained  by  M.  Bernard,  that  the  substance 

1  The  following  are  given  by  Magendie  as  the  proportions  in  which  different  sugars 
require  to  be  injected  into  the  jugular,  in  order  that  they  should  be  discoverable  in  the 
urine. 

Cane-sugar         ;>    -a**  •  ;;y  -.         .         .        •*,.•'  v:;     «      '  ;         1 
Mannite      .        ^{       ,       ,v»*.    .•»•.  •  Jj  .- ..,  «j  ..•', .» * ,:;  '*-.!,   ;.  '     ;„ .'..      1 

Sugar  of  Milk     .  '  v  ,        c         . "       . ''      ,.  \  ...  .  , .    f ,  ;    .         5 

Glucose      .        ,.*      .    :     ,*..     fr         .',     .*,    :.'      V       '..'       .       50 
Sugar  of  the  Liver      .       ..      .  vJ      '.        .     ,'•!-'•'•         .     240 

Thus  we  see  that  50  times  as  much  of  glucose  as  of  cane-sugar,  and  nearly  5  times  as 
much  of  liver-sugar  as  of  glucose,  is  required  to  produce  this  effect.  (See  "  L' Union 
Medicale,"  1849,  Nos.  72,  75,  79.) 

2  "Physiological  Chemistry,"  vol.  i.  p.  289. 

*  "Gazette  Medicale,"  1850,  No.  5. 

4  "Philos.  Magaz.,"  April  and  May,  1845,  and  "Medical  Gazette,"  Oct.  10,  1845. 

*  "Compt.  Rend."  torn.  xxx.  pp.  191,  192. 


SACCHARINE   COMPOUNDS.  77 

of  the  liver  contains  sugar,  even  in  animals  that  have  been  fed  for  some  time  on 
animal  food  alone  (a  discovery  which  has  been  verified  in  the  Giessen  Laboratory) 
— that  the  blood  of  the  hepatic  vein  of  such  animals  contains  sugar,  although 
none  is  to  be  found  in  that  of  the  vena  portae — and  that  sugar  is  contained  in 
the  liver  of  embryos,  both  of  mammals  and  oviparous  animals.  In  the  case  of 
a  healthy  adult  who  was  guillotined  while  fasting,  it  was  calculated,  from  the 
analysis  of  a  portion  of  the  liver,  that  the  whole  mass  of  it  must  have  contained 
360  grains  of  sugar.  In  Herbivorous  animals,  whose  food  contains  a  large  sup- 
ply of  amylaceous  and  saccharine  matter,  it  appears  that  the  liver  does  not  thus 
furnish  any  large  quantity  of  this  sugar;  whilst  on  the  other  hand,  a  portion  of 
the  saccharine  constituents  of  the  portal  blood  seems  to  be  converted  into  fatty 
matter  in  its  passage  through  the  liver.  But  in  Carnivorous  animals,  which 
have  already  a  supply  of  fat  in  their  food,  but  no  sugar,  the  transforming  process 
would  seem  to  be  of  a  different  kind,  sugar  being  generated  de  novo,  although 
from  what  element  of  the  blood  it  is  produced,  has  not  yet  been  clearly  deter- 
mined. There  seems  a  strong  probability,  however,  that  the  production  of  sugar 
takes  place  at  the  expense  of  protein-compounds ;  and  that  it  is  the  chief  means 
by  which  the  products  of  the  disintegration  of  muscular  and  other  albuminous 
tissues  are  made  available  for  the  maintenance  of  animal  heat  by  the  combustive 
process ;  and  this  view  derives  confirmation  from  the  fact,  that  a  new  form  of 
Sugar,  termed  Inosite,  whose  formula  is  120,  16H,  160,  has  been  recently 
discovered  by  Scherer  in  the  "juice  of  flesh,"  where  its  presence  is  almost  un- 
doubtedly to  be  attributed  to  the  disintegration  of  muscular  tissue.1  (See  also 
§  91,  VI.)  Of  the  characters  of  the  sugar  thus  produced  in  the  liver,  little  is 
yet  definitely  known  "}  but  it  would  appear  far  to  surpass  even  glucose  in  the 
readiness  with  which  it  is  carried  off  by  the  respiratory  process ;  for,  according 
to  the  statement  of  M.  Bernard,  as  much  as  12  grammes  may  be  injected  into 
the  blood  with  no  more  effect  upon  the  urine  than  is  produced  by  2.5  grammes 
of  glucose,  or  by  .05  of  cane-sugar.2 

47.  This  metamorphic  action  of  the  liver  would  seem  to  be  influenced  by 
conditions  of  the  nervous  system ;  for  when  the  upper  part  of  the  medulla  ob- 
longata,  near  the  origin  of  the  pneumogastric  nerve,3  is  irritated  by  puncture  or 
by  a  slight  galvanic  shock,  the  production  of  sugar  in  the  liver  takes  place  to 
so  great  an  extent,  that  a  portion  of  this  substance  finds  its  way  into  the  urine, 
and  a  temporary  artificial  diabetes  is  speedily  established.  This  effect  so  speedily 
ensues,  that  sugar  has  been  detected  in  the  general  mass  of  the  blood,  and  in 
every  secretion  formed  from  it,  except  the  saliva  (into  which  he  never  found  it 
enter)  within  twenty  minutes  after  the  operation.  It  is  even  possible,  accord- 

1  "Ann.  der  Chem.  und  Pharm.,"  band  Ixxiii.  p.  322. 

2  It  is  considered  by  M.  Bernard,  that  diabetic  sugar  rather  corresponds  to  this  "  sugar 
of  the  liver,"  than  it  does  to  glucose.     He  found  no  less  than  833  grains  of  sugar  in  the 
liver  of  a  diabetic  subject ;  and  he  remarks  that  the  liver  is  generally  hypertrophied  in 
this  disease.     Hence  he  looks  to  the  liver  as  its  primary  seat ;  and  imputes  the  glycosuria 
to  an  excessive  production  of  sugar  in  the  liver,  which  would  seem  then  to  exercise  its 
metamorphic  power  upon  the  azotized  constituents  of  the  blood,  and  thus  to  destroy  the 
material  for  the  nutritive  processes — an  idea  that  corresponds  well  with  the  phenomena  of 
the  disease,  which  indicate  an  impoverishment  of  the  nutritive  fluid,  the  solids  of  the  body 
exhibiting  a  rapid  waste,  notwithstanding  that  there  may  be  an  extraordinary  appetite, 
and  a  very  large  amount  of  azotized  nutriment  may  be  taken.     Moreover,  it  would  seem, 
from  Dr.  Prout's  observations,  as  if  the  presence  of  a  small  quantity  of  saccharine  matter 
in  the  food  tended  to  promote  this  metamorphosis  in  its  other  constituents ;  the  eating  of 
a  single  pear  having  been  observed  by  him  to  neutralize  all  the  benefit  which  had  been 
obtained  by  an  abstinence  from  saccharine  and  amylaceous  matters,  prolonged  through 
several  months. 

3  The  part  of  which  the  injury  is  most  effectual  in  producing  this  result,  is  that  which 
lies  in  the  groove  between  the  corpora  restiformia  and  corpora  olivaria,  and  over  the  ad- 
joining part  of  the  latter. 


78  CHEMICAL   COMPONENTS    OF   THE    HUMAN   BODY. 

ing  to  M.  Bernard,  to  predict  the  amount  of  sugar  that  will  be  secreted,  accord- 
ing to  the  depth  of  the  incision.  On  the  other  hand,  if  the  injury  thus  done  be 
too  great,  or  if  a  violent  electric  shock  be  transmitted  through  the  medulla  ob- 
longata,  or  any  other  severe  lesion  be  inflicted  on  the  nervous  system,  the  pro- 
duction of  sugar  is  suspended ;  and  it  appears  that  the  same  suspension  may 
occur  as  a  result  of  diseases  which  produce  a  diminution  of  nervous  power. 
Division  of  the  pneumogastric  nerves  usually  prevents  the  irritation  of  the 
medulla  oblongata  from  exerting  its  usual  effect,  and  even  checks  the  production 
of  sugar  when  it  has  already  appeared  in  the  urine ;  but  this  result  is  by  no 
means  constant. — The  duration  of  the  presence  of  sugar  in  the  urine  after  the 
operation  is  variable,  according  to  the  animal  experimented  on  and  the  method 
employed ;  in  general,  it  lasts  forty-eight  hours  in  the  rabbit,  and  four  days  in 
the  dog ;  but  in  one  dog  it  continued  for  as  much  as  seven  days.  The  animals 
are  extremely  restless  during  this  period;  the  respiratory  movements  are 
hurried ;  the  arterial  blood  presents  almost  a  venous  tint ;  the  quantity  of  car- 
bonic acid  given  off  is  augmented ;  nevertheless,  the  temperature  of  the  body  is 
diminished  several  degrees.1 

48.  In  close  relation  with  the  Sugars,  both  chemically  and  physiologically, 
stands  Lactic  Acid,  the  presence  of  which,  as  a  normal  element  of  the  blood, 
and  as  performing  very  important  functions  in  the  economy,  may  now  be  re- 
garded as  well  established ;  and  it  will  be  conveniently  considered  here,  although 
it  might  be  in  some  respects  more  appropriately  placed  in  the  category  of  excre- 
mentitious  matters. — This  substance,  in  its  most  concentrated  state,  is  a  color- 
less, inodorous,  thick,  syrupy  fluid,  which  cannot  be  solidified  by  the  most  intense 
cold,  dissolves  readily  in  water,  alcohol,  and  ether,  has  a  strongly  acid  taste  and 
reaction,  and  displaces  not  merely  volatile  acids,  but  even  many  of  the  stronger 
mineral  acids,  from  their  salts.  With  bases  it  generally  forms  neutral  salts,  all 
of  which  are  soluble  in  water ;  but  the  alkaline  lactates,  and  some  others,  cannot 
be  made  to  crystallize ;  being  only  brought,  by  the  greatest  concentration,  to  the 
condition  of  syrupy  fluids.  The  composition  of  this  acid  is  considered  to  be  60, 
5H,  50;  and  it  thus  bears  a  close  relation  to  that  of  Sugar,  being  exactly  half 
one  equiv.  of  anhydrous  Sugar-}- one  equiv.  of  Water.  It  is,  in  fact,  from  sugar 
or  starch  that  it  is  most  directly  produced ;  being  the  result  of  a  new  arrangement 
of  the  atoms  of  these  substances  under  the  influence  of  an  azotized  ferment,  as 
when  milk  is  turned  sour  by  the  action  of  its  casein  upon  its  sugar.  But  an  acid 
may  be  extracted  from  the  "  juice  of  flesh/'  which,  whilst  apparently  identical  in 

1  This  last  fact  appears  at  first  sight  to  stand  in  marked  opposition  to  the  chemical 
theory  of  Animal  Heat ;  but  the  Author  would  suggest  that  the  following  may  be  its  ex- 
planation.— The  production  of  heat  being  dependent  upon  the  combustion  (or  union  with 
oxygen),  not  merely  of  carbon,  but  of  hydrogen,  and  the  amount  of  heat  disengaged  by 
the  combustion  of  hydrogen  being  much  greater  than  that  given  off  by  the  combustion  of 
its  equivalent  of  carbon,  we  might  expect  that  the  conversion  of  a  fatty  substance,  which 
is  almost  entirely  composed  of  hydrogen  and  carbon,  into  water  and  carbonic  acid,  shall 
give  off  a  far  larger  amount  of  heat  than  the  combustion  of  a  farinaceous  or  saccharine 
substance,  in  which  there  is  only  carbon  to  be  burned  off,  the  hydrogen  being  already 
united  with  oxygen  in  the  proportion  to  form  water.  Experience  shows  that  such  is  the 
case ;  for  in  the  Arctic  regions,  ordinary  bread  is  found  to  be  very  inefficient  for  the  main- 
tenance of  animal  heat,  although  an  ample  supply  of  oleaginous  matters  is  completely  effect- 
ual for  this  purpose ;  and,  as  Sir  John  Richardson  has  informed  the  Author,  it  has  been 
recently  found  by  the  Hudson's  Bay  traders,  that  maize  bread,  which  contains  a  considera- 
ble proportion  of  oil,  is  a  most  supporting  food.  Consequently,  when  the  production  of 
fat  by  the  liver  is  suspended,  and  the  production  of  sugar  takes  its  place>  the  amount  of 
heat  generated  by  the  consumption  of  even  an  augmented  quantity  of  the  latter,  will  not 
be  equal  to  that  resulting  from  the  combustion  of  the  former ;  for  only  carbon  will  be 
burned  off  in  the  one  case,  whilst  both  carbon  and  hydrogen  were  consumed  in  the  other. 
The  above  account  of  the  researches  of  M.  Bernard  is  derived  from  the  sources  already 
referred  to  (§  40,  note). 


SACCHARINE   COMPOUNDS.  79 

composition  and  in  most  essential  properties  with  that  obtained  from  the  fermen- 
tation of  sugar,  differs  from  it  in  certain  of  the  properties  of  the  salts  which  it 
forms  with  bases;  and  the  acid  of  the  juice  of  flesh  has  been  recently  distin- 
guished as  a  lactic  acid,  whilst  that  obtained  in  the  usual  way  (with  which  the 
acid  of  the  gastric  fluid  corresponds)  is  designated  as  b  lactic  acid.  This  distinc- 
tion will  be  found  to  be  of  much  importance,  when  we  examine  into  the  sources 
of  lactic  acid  in  the  animal  economy. — Much  discussion  has  taken  place  at  dif- 
ferent times  with  regard  to  the  existence  of  lactic  acid  in  various  parts  of  the 
animal  body,  chiefly  in  consequence  of  the  extreme  difficulty  of  determining  its 
presence  by  ordinary  chemical  tests ;  the  production  of  some  of  its  crystalline  salts, 
and  the  accurate  measurement  of  the  angles  of  these,  being  the  only  method  on 
which  reliance  can  be  placed.  The  following,  according  to  Lehmann,  may  be 
regarded  as  well-established  facts,  free  from  the  errors  of  the  earlier  analyses. 

49.  Lactic  acid  is  a  constant  constituent  of  the  gastric  juice ;  and  as  this  is 
true  of  carnivorous  as  well  as  of  herbivorous  animals,  it  cannot  be  looked  on  in 
any  other  light  than  as  a  secretion  from  the  blood.  It  is  also  found  in  the  con- 
tents of  the  small  intestines,  which,  notwithstanding  the  neutralizing  power  of 
the  bile,  usually  exhibit  an  acid  reaction ;  but  although  its  presence  there  may 
be  attributed  to  the  admixture  of  the  gastric  solvent,  yet,  as  it  is  found  in  much 
larger  amount  in  the  small  intestines  of  herbivorous  than  in  those  of  carnivorous 
animals,  and  as  its  proportion  is  increased  in  the  former  by  the  ingestion  of  fari- 
naceous food,  the  excess  would  seem  to  be  due  to  the  direct  transformation  of 
amylaceous  matters  in  the  alimentary  canal.  The  acid  reaction  of  the  mucus 
which  lines  the  intestinal  tube  has  been  found  to  be  due  to  lactic  acid ;  as  is  also 
that  which  often  presents  itself  in  the  contents  of  the  large  intestine,  especially 
when  vegetable  food  has  been  ingested.  Distinct  evidence  has  been  obtained  of 
the  presence  of  lactic  acid  in  the  chyle  of  herbivorous  animals,  in  which  it  is 
obviously  derived  from  the  food;  on  the  other  hand,  there  are  indications  of  its 
existence  in  the  lymph,  where  its  presence  must  be  rather  attributed  to  its  pro- 
duction in  the  muscular  substance.  It  seems  impossible  to  demonstrate  the 
existence  of  lactic  acid  in  healthy  blood,  by  direct  experiment;  but,  as  Lehniann 
remarks,  athe  simplest  induction  proves  that  it  must  be  present  there,  even  if  it 
only  remains  for  a  very  short  period;"  since  in  no  other  way  can  it  be  under- 
stood how  the  lactic  acid  introduced  by  the  chyle,  or  generated  in  the  muscular 
substance,  can  find  its  way  into  the  gastric,  urinary,  cutaneous,  or  other  secre- 
tions. The  fact  appears  to  be  that,  in  the  healthy  state  of  the  system,  lactic 
acid  is  decomposed  by  the  respiratory  process,  or  is  eliminated  from  the  blood 
by  the  secretory  operations,  as  fast  as  it  finds  its  way  into  the  circulation ;  and 
thus,  as  in  the  case  of  urea,  it  never  accumulates  in  the  blood  to  such  a  degree 
as  to  make  its  presence  evident,  unless  it  be  either  introduced  in  undue  propor- 
tion, or  its  elimination  be  checked.  It  seems  probable  that  when  the  blood  pre- 
sents an  acid  reaction,  as  happens  in  some  diseases,  this  is  to  be  attributed  to  an 
excess  of  lactic  acid ;  since  this  substance,  although  not  distinctly  detected  in 
such  blood,  has  been  clearly  made  out  in  the  fluids  exuded  from  it.  The  rapidity 
with  which  lactic  acid  is  decomposed  by  the  respiratory  process  (carbonic  acid 
being  left,  in  combination  with  the  basis),  may  be  judged  of  by  the  fact  that 
within  from  five  to  thirteen  minutes  after  considerable  quantities  of  the  alkaline 
lactates  have  been  introduced  into  the  stomach,  or  have  been  injected  into  the 
current  of  the  circulation,  the  urine  is  found  to  be  rendered  alkaline  by  the  pre- 
sence of  their  carbonates. — The  existence  of  free  lactic  acid  in  the  juice  of  flesh, 
as  long  ago  asserted  by  Berzelius,  may  now  be  considered  as  a  certainty;  and  it 
is  probable  that,  as  further  maintained  by  Berzelius,  the  amount  of  free  lactic 
acid  in  a  muscle  is  proportioned  to  the  degree  in  which  it  had  been  previously 
exercised.  Now,  that  this  lactic  acid  cannot  have  been  generated  by  the  direct 
transformation  of  the  elements  of  food,  and  merely  attracted  from  the  blood  by 


80  CHEMICAL   COMPONENTS    OF   THE   HUMAN   BODY. 

the  muscular  substance,  but  is  one  of  the  products  of  the  direct  transformation 
of  that  substance  consequent  upon  the  exertion  of  its  vital  powers,  appears  from 
this,  that  it  is  found  in  the  muscles  of  purely  carnivorous  animals  in  no  smaller 
amount  than  in  those  of  the  animals  that  have  consumed  amylaceous  or  saccha- 
rine matters  as  food ;  and  although  it  has  not  yet  been  produced  artificially,  either 
by  fermentation  or  otherwise,  from  any  nitrogenous  animal  matter,  yet,  as  is 
pointed  out  by  Lehmann,  there  are  strong  indications  that  such  a  conversion  is 
by  no  means  hypothetical  ;  and  all  that  has  been  said  of  the  generation  of  sugar 
in  the  body  (§  46),  of  course  applies  ecjually  to  lactic  acid. — The  occasional  pre- 
sence of  lactic  acid  in  the  urine,  appears  to  have  been  fully  proved  by  the  re- 
searches of  Lehmann;  who  has  shown  that,  although  it  cannot  be  considered  as 
a  normal  constituent  of  that  excretion,  it  is  liable  to  appear  there,  whenever  the 
quantity  introduced  into  the  blood  in  a  given  time,  whether  by  the  transforma- 
tion of  the  amylaceous  and  saccharine  constituents  of  the  food,  or  by  the  meta- 
morphosis of  muscular  tissue,  is  greater  than  the  respiratory  process  can  carry 
off;  and  thus  it  may  be  habitually  present  in  the  urine  of  individuals  whose  re- 
spiration is  obstructed,  notwithstanding  that  no  actual  excess  of  it  has  been  gene- 
rated within  their  bodies. — Lactic  acid  seems  also  to  be  occasionally  present  in 
the  sweat  (which  owes  its  sour  smell,  however,  to  acetic  acid) ;  and  its  presence 
has  been  suspected  also  in  the  bile,  though  with  respect  to  this  it  would  not  be 
safe  to  make  a  positive  statement. 

50.  On  the  whole,  then,  it  may  be  positively  affirmed,  that  Lactic  acid  is  a 
normal  constituent  of  the  Human  body,  and  that  it  is  to  be  looked  on  under  two 
aspects,  both  as  to  its  origin  and  its  destination.    Its  origin  may  be  attributed  : 
1st,  to  the  direct  transformation  of  the  amylaceous  and  saccharine  constituents 
of  the  food ;  and  2d,  to  the  metamorphosis  of  muscular  and  (probably)  other 
azotized  tissues.    On  the  other  hand,  its  destination  may  be  considered  as  being  : 
1st,  to  supply  a  pabulum  for  the  combustive  process,  and  thus  to  contribute 
in  maintaining  the  heat  of  the  body ;  and  2d,  to  take  part  in  the  reduction  of 
the  albuminous  and  other  constituents  of  food  in  the  stomach,  either  by  itself 
acting  as  the  solvent,  or  by  decomposing  the  chlorides  of  calcium  or  sodium 
contained  in  the  gastric  fluid,  and  by  thus  setting  free  hydrochloric  acid.     Its 
presence  in  the  urinary  secretions  may  be  regarded  as  exceptional ;  the  kidneys 
affording  (so  to  speak)  a  safety-valve,  whereby  the  accumulation  of  lactic  acid 
in  the  blood  is  prevented. 

5.  Excrementitious  Substances. 

51.  Although  it  might  seem  more  correct  to  proceed,  in  the  next  place,  to 
speak  of  the  Mineral  or  Inorganic  constituents  of  the  Human  body,  yet  it  will 
better  serve  the  purpose  of  illustrating  the  chemical  metamorphoses  which  take 
place  in  the  economy,  if  we  next  direct  our  attention  to  those  Organic  compounds, 
which  may  be  regarded  as  the  products  of  the  disintegration  of  the  tissues,  or 
of  the  decomposition  of  superfluous  alimentary  matter,  and  which,  wherever 
they  are  found  within  the  living  body,  may  be  considered  as  on  their  way  to  be 
eliminated  from  it  by  the  action  of  the  excretory  organs. — Of  these  excremen- 
titious  matters  it  may  be  stated  generally,  that,  although  their  composition  is 
such  as  (with  very  few  exceptions)  the  Chemist  is  unable  to  imitate  by  the 
artificial  union  of  their  components,  yet  it  is  far  simpler  than  that  of  the  Histo- 
genetic  substances ;  the  number  of  the  combining  equivalents  of  their  elements 
being  smaller,  and  the  mode  in  which  they  are  united  (as  indicated  by  the  de- 
compositions of  which  these  compounds  are  susceptible)  being  usually  much 
more  apparent.     Moreover,  several  of  them  are  remarkable  for  their  capability 
of  assuming  a  crystalline  form  ;  which,  as  long  since  pointed  out  by  Dr.  Prout, 
is  peculiarly  indicative  of  their  incapacity  for  serving  as  materials  for  the  con- 


EXCREMENTITIOUS    SUBSTANCES.  81 

struction  of  living  tissues.  And  of  all  of  them  it  may  be  said,  that  their  accu- 
mulation in  the  Blood  is  extremely  deleterious  ;  so  that,  if  they  should  be  gene- 
rated faster  than  the  excretory  organs  can  remove  them,  a  serious  derangement 
of  the  vital  economy  is  produced.  These  peculiarities  separate  the  proper 
excrementitious  substances  from  all  those  which  are  introduced  into  the  body 
as  food,  and  which  serve  either  for  the  genesis  of  tissue,  or  for  the  supply  of  the 
combustive  process ;  but,  as  already  remarked,  the  two  groups  are  connected  by 
intermediate  links — cholesterine,  though  a  normal  element  of  the  blood,  being 
a  component  of  the  biliary  excretion — whilst  lactic  acid,  though  a  most  import- 
ant ingredient  in  the  gastric  juice,  is  an  essentially  excrementitious  product  of 
the  metamorphosis  of  the  saccharine  compounds,  whose  constant  and  complete 
elimination  from  the  blood  seems  to  be  most  carefully  provided  for. — Like  the 
histogenetic  substances,  the  proper  Excrementitious  matters  may  be  divided 
into  two  principal  groups,  in  one  of  which  nitrogen  is  the  predominating  and 
characteristic  ingredient,  whilst  in  the  other  we  find  carbo-hydrogen  in  excess ; 
and  these  two  groups  form  the  chief  components  of  the  Urinary  and  the  Biliary 
excretions  respectively. 

52.  Of  the  first  of  these  groups,  the  substance  of  by  far  the  most  importance 
in  the  Human  body,  is  Urea ;  and  this,  although  not  possessing  an  alkaline 
reaction,  is  regarded  as  basic,  since  it  has  the  power  of  forming  saline  compounds 
with  acids.  Urea  is  obtained  from  the  fluids  containing  it,  in  a  crystalline 
form :  but  the  shape  of  its  crystals  varies  according  as  it  separates  rapidly  or 
gradually ;  these  being  white,  silky,  glistening  needles  in  the  former  case  ;  and 
flat,  colorless,  four-sided  prisms,  terminated  by  one  or  two  oblique  surfaces,  in 
the  latter.  Urea  is  devoid  of  smell,  has  a  saltish  cooling  taste,  and  is  unaffected 
by  exposure  to  the  atmosphere.  It  dissolves  readily  in  its  weight  of  cold  water, 
and  in  hot  water  in  every  proportion  ;  it  is  also  soluble  in  4  or  5  parts  of  cold, 
and  in  2  parts  of  warm  alcohol  ]  and  it  is  not  precipitated  from  its  solutions  by 
metallic  salts,  tannic  acid,  or  any  other  reagent.  It  has  been  stated  to  combine 
as  a  base  with  a  considerable  number  of  acids ;  but  the  only  salts  which  it  is 
certainly  known  to  form,  are  the  nitrate,  oxalate,  and  hydrochlorate ,  and  it  is 
by  the  use  of  either  nitric  or  oxalic  acid,  that  urea  is  most  readily  obtained  from 
its  solutions,  since  the  salts  which  it  forms  with  them  are  far  less  soluble  in 
water  than  is  urea  itself.  Urea  unites  also,  however,  with  many  salts,  some  of 
which  hold  it  in  such  firm  combination,  that  it  cannot  be  thus  separated  from 
them. — The  composition  of  Urea  is  extremely  simple  in  comparison  with  that 
of  the  azotized  histogenetic  substances,  its  formula  being  2  Carbon,  4  Hydrogen, 
2  Nitrogen,  and  2  Oxygen  ;  but  Chemists  are  not  yet  agreed  upon  the  mode  in 
which  these  atoms  are  united.  The  number  of  the  combining  equivalents  of  the 
respective  elements  is  the  same  as  that  which  exists  in  the  Cyanate  of  Ammonia ; 
and  it  was  long  since  ascertained  by  Wohler,  that  this  salt  may  be  converted 
into  (basic)  urea  by  the  rearrangement  of  its  atoms,  without  any  alteration  in 
its  ultimate  composition.  This  artificial  production  of  urea  may  be  considered 
as  one  of  the  most  interesting  discoveries  ever  made  in  organic  chemistry.  When 
organic  matters,  either  putrefying  or  capable  of  undergoing  putrefaction,  are 
mixed  with  an  aqueous  solution  of  Urea,  the  latter  is  soon  converted,  with  the 
addition  of  two  equivalents  of  water,  into  Carbonic  acid  and  Ammonia ;  thus 
restoring  to  the  atmosphere,  in  their  original  state  of  combination,  the  compounds 
at  whose  expense  the  Plant  first  generated  the  organic  constituents  of  the  Animal 
body.  This  change  takes  place  in  the  Urine  very  soon  after  its  expulsion  from 
the  body ;  the  mucus  of  the  bladder  acting  as  the  ferment  required.1 

1  See  MM.  Dumas  and  Boussingault  "  On  the  Chemical  and  Physiological  Balance  of 
Organic  Nature,"  3d  edit,  (transl.),  p.  41 ;  and  the  Author's  "Principles  of  Physiology, 
General  and  Comparative,"  p.  186,  Am.  Ed. 

6 


82  CHEMICAL   COMPONENTS   OF   THE   HUMAN   BODY. 

53.  That  Urea  is  to  be  regarded  as  one  of  the  most  important  products  of  the 
disintegration  of  the  azotized  tissues  of  the  body,  cannot  now  be  doubted  for  a 
moment.  It  may  be  produced  by  the  decomposition  of  various  nitrogenous  sub- 
stances, both  natural  and  artificial;  and  it  is  a  fact  of  the  greatest  physiological 
interest  (as  will  be  presently  apparent),  that  it  may  be  obtained  from  creatine  by 
the  action  of  baryta-water  or  alkalies.  In  inquiring  into  the  precise  mode  of  its 
production,  we  must  trace  it  backwards  (so  to  speak)  from  the  Urine,  of  which 
in  Man  it  is  the  characteristic  ingredient. — There  is  now  abundant  evidence,  that 
urea  is  not  generated  (as  formerly  supposed)  in  the  act  of  secretion,  but  that  it 
exists  preformed  in  the  blood ;  for  not  only  does  it  accumulate  largely  in  the 
circulating  fluid,  when  its  elimination  by  the  normal  outlet  is  checked,  but  it 
presents  itself,  though  in  extremely  small  amount,  in  healthy  blood,  as  has  been 
determined  by  Strahl  and  Lieberkiihn,  Garrod,  and  (still  more  decisively)  by 
Lehmann.  That  its  proportion  in  the  circulating  fluid  never  arises  to  an  amount 
that  would  render  it  easily  detectable,  notwithstanding  that  it  is  continually 
either  being  generated  within  the  vessels,  or  being  absorbed  into  them  from 
without,  is  readily  accounted  for  by  the  avidity  (so  to  speak)  with  which  the 
kidney  seizes  upon  even  the  smallest  proportion  of  this  substance,  and  eliminates 
it  from  the  nutritive  fluid.  The  purpose  with  which  this  organ  has  been  enabled 
thus  to  act,  becomes  obvious  enough  when  it  is  remembered  that  Urea  is  a  sub- 
stance whose  accumulation  in  the  blood  is  most  pernicious ;  as  is  seen  in  various 
forms  of  disease,  of  which  the  most  severe  symptoms,  and  not  unfrequently  the 
fatal  termination  itself,  are  directly  attributable  to  this  mode  of  poisoning. 
Moreover,  it  has  been  shown,  by  the  calculations  of  Lehmann,  that  it  would 
require  the  whole  urea  generated  in  the  system  to  accumulate  in  the  blood  for 
at  least  an  -hour  (so  as  to  impregnate  it  with  l-24th  part  of  the  total  quantity 
passed  in  one  day)  before  it  would  amount  to  such  a  percentage  as  can  be  cer- 
tainly detected  in  that  fluid.  Even  if  it  could  never  be  recognized  in  healthy 
blood,  therefore,  no  argument  would  be  thence  furnished  against  the  doctrine 
that  it  is  present  as  such  in  the  blood  before  it  passes  to  the  kidneys.  This 
doctrine  is  confirmed  by  the  fact,  that  Urea  may  be  discovered  in  various  fluids 
separated  from  the  blood ;  and  this  not  only  when  the  normal  elimination  is 
checked,  but  also  in  the  usual  state  of  health.  Thus  it  has  been  found  by 
Millon  and  Wohler  in  the  vitreous  and  aqueous  humors  of  the  eye,  by  Rees  in 
milk  and  liquor  amnii,  and  by  Landerer  in  the  sweat ;  and  when  the  renal 
arteries  have  been  tied,  or  the  kidneys  have  been  removed,  or  their  secreting 
action  has  been  interfered  with  by  injury  to  their  nerves  or  by  disease,  Urea 
has  been  detected  in  almost  every  secretion  and  fluid  exudation  that  has  been 
drawn  or  poured  forth  from  the  circulating  current. — The  question  now  arises, 
whether  the  Urea  thus  contained  within  the  blood-vessels  is  generated  there,  or 
whether  it  is  taken  up  from  extraneous  sources,  to  be  conveyed  by  the  current 
of  the  circulation  to  the  excretory  outlets.  Now  in  favor  of  the  first  of  these 
opinions  it  may  be  urged,  that,  as  will  appear  hereafter  (CHAP,  xn.,  SECT.  3), 
Urea  is  not  formed  only  from  the  disintegration  of  the  living  tissues,  but  that  it  is 
also  generated  at  the  expense  of  superfluous  alimentary  materials,  which,  having 
been  introduced  into  the  blood,  and  not  being  required  to  supply  the  wants  of 
the  system,  pass  into  decomposition  without  ever  having  been  converted  into 
tissue.  Such  being  the  case,  a  part  at  least  of  the  Urea  that  is  eliminated  from 
the  blood  may  be  considered  as  having  been  generated  within  the  vessels ;  since 
it  is  very  seldom  that  of  the  supply  of  nitrogenous  aliment  ingested  by  man, 
there  is  not  some  portion  that  may  be  considered  superfluous.  Now  of  that 
portion  which  has  its  origin  in  the  disintegration  of  the  tissues,  the  greater  part 
may  be  set  down  to  metamorphosis  of  the  muscular  substance,  since  it  is  found 
that  muscular  exercise  has  a  special  power  of  augmenting  the  quantity  of  urea 


EXCREMENTITIOUS    SUBSTANCES.  83 

in  the  urine ;  and  the  question  arises,  whether  Urea  is  one  of  the  immediate 
products  of  this  metamorphosis,  or  whether  some  other  compound  is  first  gene- 
rated, which  is  converted  into  urea  after  its  absorption  into  the  circulation. 
Now  although  it  is  impossible  in  the  present  state  of  our  knowledge  to  answer 
this  question  in  either  way  with  any  degree  of  certainty,  yet  there  is  certainly 
a  strong  probability  that  the  second  of  these  views  is  the  correct  one ;  for,  in 
the  first  place,  no  trace  of  urea  has  been  found  in  the  "  juice  of  flesh ;"  whilst, 
secondly,  this  juice  contains  a  considerable  amount  of  the  substance  (creatine), 
from  which  urea  may  be  generated  artificially  (§  60).  That  uric  acid  also  may 
be  converted  into  urea  in  the  circulating  blood,  seems  to  have  been  distinctly 
proved  by  the  experiments  to  be  presently  cited  (§  55).  It  appears  most  pro- 
bable, therefore,  that  the  products  of  the  disintegration  of  muscle  are  received 
into  the  blood,  not  in  the  form  of  urea  itself,  but  in  that  of  creatine  or  of  some 
other  compound,  which  is  capable  of  being  resolved  into  urea  by  further 
metamorphosis  ;  and  that  the  immediate  source  of  urea,  therefore,  in  the  latter 
case  as  in  the  former,  is  one  of  the  constituents  of  the  circulating  blood. 

54.  Next  in  importance  to  Urea,  and  taking  its  place  as  the  predominating 
component  of  the  urinary  excretion  of  most  animals  below  Mammalia,  is  Uric  Acid. 
The  small  proportion,  however,  in  which  this  substance  normally  presents  itself 
in  the  urine  of  Man — its  usual  amount  being  less  than  1  part  in  1000  of  Urine, 
whilst  that  of  Urea  is  from  about  25  to  32  parts  in  1000 — might  seem  to  ren- 
der it  unnecessary  to  enter  at  length  into  its  chemical  peculiarities  or  its  physi- 
ological relations.  But  although  in  the  healthy  system  it  may  seem  to  perform 
a  subordinate  part,  there  can  be  no  doubt  whatever  that  in  various  disordered 
states  of  the  body  an  augmented  production  of  uric  acid,  or  a  deficient  meta- 
morphosis or  elimination  of  it,  or  both  conditions  combined,  exercise  a  very 
important  influence,  and  become  the  sources  of  other  perversions;  and  it  is 
therefore  a  matter  of  great  consequence  to  trace  out,  so  far  as  is  possible,  the 
entire  history  of  this  substance,  both  chemical  and  physiological. — Pure  uric 
acid  occurs  either  in  a  glistening  white  powder,  or  in  very  minute  scales,  whose 
form,  when  they  are  examined  by  the  microscope,  is  found  to  be  distinctly 
crystalline,  although  the  shape  of  the  crystals  is  liable  to  considerable  variation. 
As  it  is  by  the  microscope,  rather  than  by  any  chemical  tests,  that  the  presence 
of  uric  acid  is  most  readily  detected,  and  as  its  Protean  forms  of  crystallization, 
although  easily  reduced  by  the  crystallographer  to  a  determinate  system,  are 
liable  to  perplex  those  who  have  not  the  advantage  of  his  scientific  knowledge, 
it  will  be  advantageous  here  to  cite  the  description  of  them  given  by  Prof. 
Lehmann.  "Uric  acid,  when  it  gradually  and  spontaneously  separates  from 
urine,  appears  in  most  cases  in  the  whetstone  form,  that  is,  it  forms  flat  tablets, 
which  resemble  sections  made  with  the  double  knife  through  strongly  bi-convex 
lenses,  or  rhombic  tablets  whose  obtuse  angles  have  been  rounded.  As  the 
urinary  pigment  adheres  very  tenaciously  to  the  uric  acid,  it  is  only  rarely  that 
these  crystals  are  devoid  of  color,  and  if  we  see  a  crystal  presenting  an  extra- 
ordinary form  and  of  a  yellow  color,  the  probability  is  that  it  is  a  crystal  of 
uric  acid.  On  artificially  separating  uric  acid  from  its  salts,  it  often  appears  in 
perfect  rhombic  tablets,  and  even  oftener  in  six-sided  plates  resembling  those  of 
cystine ;  when  uric  acid  crystallizes  very  slowly,  it  forms  elongated  rectangular 
tablets  or  parallelepipeds,  or  rectangular  four-sided  prisms,  with  horizontal  ter- 
minal planes;  the  latter  are  often  grouped  together  in  clusters;  we  have  also 
barrel-shaped  or  cylindrical  prisms,  which  are  composed  of  the  more  rarely- 
occurring  elliptic  tablets;  and  finally  saw-like  or  toothed  crystals,  and  many 
derivatives  of  these  forms.  If  we  cannot  decide  with  certainty  regarding  the 
presence  of  uric  acid  from  the  form  of  a  crystal,  we  must  dissolve  it  in  potash, 
place  it  under  the  microscope,  and  add  a  minute  drop  of  acetic  acid;  we  shall 


84  CHEMICAL   COMPONENTS    OF   THE    HUMAN   BODY. 

then  always  obtain  one  of  the  more  common  forms/'1  Uric  acid  is  devoid  of 
odor  and  taste;  it  requires  1800  or  1900  parts  of  hot  water,  and  14,000  or 
15,000  parts  of  water  at  the  ordinary  temperature  of  68°,  to  dissolve  it;  but  it 
dissolves  readily  in  solutions  of  the  alkaline  carbonates,  phosphates,  lactates, 
and  acetates,  abstracting  some  of  the  alkali  from  the  salts;  it  is  expelled  from 
these  solutions,  however,  by  an  excess  of  the  free  acids.  Uric  acid  is  one  of 
the  weakest  class  of  acids;  it  does  not  redden  litmus  paper;  it  does  not  directly 
expel  carbonic  acid  from  carbonate  of  potash,  but  simply  withdraws  a  portion 
of  the  alkali,  leaving  the  remainder  in  the  condition  of  a  bicarbonate;  and  it 
does  the  same  with  a  solution  of  basic  phosphate  of  soda,  changing  its  pre- 
viously alkaline  into  an  acid  reaction,  by  the  production  of  a  biphosphate. 
According  to  the  analysis  of  Bensch,  the  formula  of  Uric  Acid  (usually  stated 
at  IOC,  4H,  4N,  60)  is  really  50,  1H,  2N,  20+ HO.  The  acid  has  not  been 
obtained,  however,  in  its  anhydrous  state;  and  its  existence  must  be  admitted 
to  be  hypothetical. 

55.  Uric  acid,  when  subjected  to  the  operation  of  various  reagents,  may  be 
made  to  undergo  a  great  number  of  changes,  and  to  give  rise  to  a  large  series 
of  organic  compounds.  Some  of  these  metamorphoses  it  is  important  to  notice 
here;  as  they  throw  light  upon  the  phenomena  of  the  living  organism.  Thus 
it  is  found  that  urea  may  be  produced  by  the  artificial  oxidation  of  uric  acid ; 
and  this  in  more  than  one  mode.  Thus,  if  four  parts  of  uric  acid  be  mixed 
with  eight  parts  of  moderately  strong  hydrochloric  acid,  and  one  part  of  chlo- 
rate of  potass  be  gradually  introduced,  Urea  is  formed,  together  with  a  new 
compound  termed  Alloxan,  which  in  its  turn  may  be  resolved  by  a  further  sup- 
ply of  oxygen  into  urea  and  oxalic  acid,  or,  by  still  higher  oxygenation,  into 
urea  and  carbonic  acid.  So,  again,  when  uric  acid  is  boiled  with  peroxide  of 
lead,  there  are  formed,  as  the  resultants  of  the  process,  an  Oxalate  of  the  pro- 
toxide of  lead,  Urea,  and  Allantoin;  this  last  being  a  substance  which  naturally 
presents  itself  in  the  fluid  of  the  allantois  of  the  foetal  calf  (being,  in  fact,  the 
secretion  of  its  temporary  kidneys),  and  which  there  seems  to  take  the  place  of 
urea,  although  its  composition  is  represented  by  a  very  different  formula  (80, 
5H,  4N,  50).  The  production  of  Urea  from  Uric  acid  is  thus  represented  by 
Prof.  Liebig: — 

C.  H.  N.  0.  C.  H.  N.  0. 

1  equiv.  hydrated  Uric  acid  =  5     223"]          ["242  2  =  1  equiv.  Urea. 

2  equivs.  Water  .         .         =2          2  |  3  6  =  3  equivs.  Carb.  acid. 

3  equivs.  Oxygen         .         =  3  |-  =  -I 

5    4    2     8j          [5    4    2     8 

Now  it  has  been  ascertained  by  the  experiments  of  Wohler  and  Frerichs,2  that 
if  urate  of  potash  be  injected  in  quantities  of  30  or  40  grains  into  the  blood- 
vessels of  rabbits,  no  uric  acid  shows  itself  in  the  urine,  but  the  quantity  of 
urea  is  enormously  increased,  and  oxalate  of  lime  makes  its  appearance ;  so  that 
a  metamorphosis  of  uric  acid  into  urea  must  have  taken  place  in  the  circulating 
current,  and  this  probably  by  means  of  the  oxidating  process  of  respiration.3 
Further,  there  is  evidence  afforded  by  the  phenomena  of  calculous  disorders, 
that  there  is  a  natural  alternation  between  the  deposits  of  uric  and  of  oxalic  acids ; 

1  "Physiological  Chemistry,"  vol  i.  p.  210. 

2  "Ann.  der  Chem.  und  Pharm.,"  band  Ixv.  pp.  338-342. 

3  According  to  Liebig  ("Familiar  Letters,"  p.  399),  this  process  is  to  be  likened  to  the 
reduction  of  the  salts  of  the  vegetable  acids,  the  citrates,  tartrates,  malates,  or  to  that  of 
the  lactates,  to  the  condition  of  carbonates;  for,  he  remarks,  "it  is  well  known  that  urea 
corresponds  in  composition  to  carbonic  acid ;  being  carbonic  acid  in  which  half  the  oxygen 
is  represented  and  replaced  by  its  equivalent  of  amide  (N,  2H)."     This  view  of  its  con- 
stitution, however  ingenious,  seems  far  from  accordant  with  the  basic  character  of  urea. 


EXCREMENTITIOUS    SUBSTANCES.  85 

the  latter  being  found  to  replace  the  former,  when  more  exercise  is  taken  by 
the  subjects  of  them,  whilst  a  still  greater  amount  of  exercise  favors  the  meta- 
morphosis of  the  uric  acid  into  urea,  by  the  higher  oxygenation  which  the  aug- 
mented respiration  will  tend  to  produce.1 — When  Uric  acid  is  dissolved  in  dilute 
nitric  acid,  and  the  fluid  is  evaporated  until  it  assumes  a  reddish  tint,  the  solu- 
tion, being  allowed  to  cool  to  150°,  and  being  then  saturated  with  ammonia, 
deposits  a  substance  which  crystallizes  in  short  four-sided  prisms,  that  present 
a  garnet-red  hue  by  transmitted  light,  but  have  a  cantharides-green  lustre  by 
reflected  light.  This  substance  has  been  named  Murexide,  on  account  of  its 
reddish-purple  color,  resembling  that  of  the  Tyrian  dye  which  was  obtained 
from  a  species  of  Murex ;  but  it  was  long  since  maintained  by  Dr.  Prout  to  be 
in  reality  a  Purpurate  of  Ammonia ;  and  this  view  of  its  composition,  although 
contested  for  some  time,  is  now  generally  admitted — the  Purpuric  acid,  or 
Murexan,  being  obtained  in  a  separate  form,  and  entering  into  combinations  of 
other  bases.  Murexide  is  one  source  of  the  colors  of  the  pink  and  lateritious 
sediments,  which  so  frequently  present  themselves  in  the  urine;  these  hues 
partly  depend,  however,  upon  the  peculiar  coloring  principles  of  that  secretion 
(§  64). — It  is  by  the  formation  of  murexide  that  the  presence  of  Uric  acid  is 
best  determined  chemically;  for  the  purplish-red  residue  which  its  solution  in 
nitric  acid  leaves  on  evaporation,  suffices  to  distinguish  it  from  every  other 
organic  substance,  except  perhaps  caffeine ;  and  whatever  doubt  may  remain  is 
dissipated  by  the  development  of  a  splendid  violet  tint  on  the  addition  of  caustic 
potash,  this  being  the  result  of  the  action  of  that  substance  on  murexide. 

56.  Owing  to  the  almost  complete  insolubility  of  Uric  Acid  in  water,  so  long 
as  it  remains  uncombined,  it  could  not  be  a  constituent  of  the  urinary  secretion, 
unless  held  in  solution  by  some  other  substance.  This  substance  appears  from 
the  researches  of  Liebig,  which  have  been  confirmed  by  other  Chemists,  to  be 
phosphate  of  soda,  which  yields  up  a  part  of  its  base  to  form  an  acid  urate  of 
soda,  and  is  itself  converted  into  a  superphosphate.  This  urate  of  soda  is  not 
possessed  of  any  great  solubility,  especially  in  cold  water ;  and  thus  it  may  be 
precipitated,  if  present  in  excess,  when  the  temperature  of  the  urine  is  lowered, 
although  it  was  in  a  state  of  perfect  solution  at  the  time  that  the  urine  was  void- 
ed. An  augmentation  of  the  normal  amount  of  uric  acid  in  the  urine  almost 
always  takes  place  when  there  is  any  febrile  disturbance  in  the  system ;  and  it 
may  be  so  great  as  to  prevent  the  whole  of  the  acid  from  being  united  with  a 
base,  so  that  free  uric  acid  presents  itself  in  the  urine.  It  is  very  seldom,  how- 
ever, that  such  is  the  case;  for  the  lateritious  sediment  deposited  in  diseases 
attended  with  fever,  consists,  according  to  Lehmann,  not  of  amorphous  uric  acid 
as  was  long  believed,  nor  of  urate  of  ammonia  as  maintained  by  Dr.  G-olding 
Bird,3  but  chiefly  of  urate  of  soda,  mixed  with  very  small  quantities  of  urate  of 
lime  and  urate  of  ammonia.  After  urine  has  been  discharged,  however,  for  an 
hour  or  more,  crystals  of  free  uric  acid  may  frequently  be  found  in  it ;  this  being 
consequent  upon  a  change  in  the  constituents  of  the  urine  itself  on  exposure  to 
the  atmosphere,  whereby  lactic  acid  is  developed  in  it,  as  has  been  demonstrated 
by  Scherer.  So,  again,  a  deposit  of  urate  of  ammonia  may  present  itself  in  urine 
that  has  been  exposed  to  the  air  for  a  still  longer  period,  and  has  undergone 
the  alkaline  fermentation ;  but  it  is  very  rare  to  find  crystals  of  this  salt  in  the 
urine  of  paraplegic  patients  which  has  become  alkaline  within  the  bladder,  and 

1  See  Prof.  Liebig's  "Chemistry  in  its  applications  to  Physiology  and  Pathology,"  2d 
edit.  p.  137. 

2  By  Dr.  Golding  Bird,  however,  it  is  still  maintained  that  uric  acid  normally  exists  in 
the  urine  in  combination  with  ammonia,  derived  from  the  phosphate  of  soda  and  ammonia 
which  he  believes  to  be  one  of  its  ordinary  constituents ;  and  that  in  the  deposits  in  question 
the  urate  of  ammonia  predominates,  though  he  allows  that  the  urates  of  soda  and  lime  are 
also  to  be  found. — See  his  "  Urinary  Deposits,"  2d  Am.  Ed.,  pp.  69  and  113. 


86  CHEMICAL   COMPONENTS    OP   THE    HUMAN   BODY. 

still  rarer  to  discover  it  in  the  urine  which  has  been  rendered  alkaline  by  the 
general  conditions  of  the  system.  As  a  general  rule,  it  may  be  stated,  that  no 
conclusions  can  be  drawn  respecting  the  amount  of  uric  acid  in  the  urine,  from 
the  formation  of  a  sediment,  either  of  this  substance  or  of  one  of  its  salts;  since 
the  deposition  of  this  sediment  will  be  determined  by  a  number  of  conditions  which 
affect  its  solubility,  independently  of  those  which  occasion  variations  in  the  ab- 
solute quantity  produced.  Among  these,  not  the  least  important  is  the  amount 
of  the  watery  portion  of  the  secretion;  since  a  diminution  of  this  may  occasion 
a  precipitation  of  urate  of  soda  or  urate  of  ammonia  on  its  cooling,  although  these 
salts  were  dissolved  in  it  at  the  temperature  of  the  body.  So,  again,  the  pre- 
sence of  lactic  acid  may  occasion  a  precipitation  of  uric  acid,  although  the  latter 
has  not  been  formed  in  excess.  The  peculiar  conditions  of  the  system  which 
give  rise  to  these  deposits,  will  have  to  be  considered  hereafter  (CHAPTER  xii., 
SECT.  3). 

57.  Tracing  back  the  formation  of  Uric  acid,  as  we  have  attempted  to  do  in  the 
case  of  Urea,  we  find  ample  evidence,  in  the  first  place,  that  it  is  not  generated 
in  the  act  of  secretion,  but  that  it  pre-exists  in  the  blood ;  as  it  has  been  de- 
tected there,  not  merely  in  diseased  states  of  the  system,  in  which  either  its 
elimination  is  checked,  or  its  production  is  increased,  or  both  conditions  concur ; 
but  even,  though  in  very  minute  quantity,  in  healthy  blood.1  Urate  of  soda 
is  found  in  abundance  in  gouty  concretions  and  tophaceous  deposits;  and  it 
has  been  observed  by  Dr.  Gr.  Bird  as  a  sort  of  efflorescence  on  the  surface  of 
the  limbs  of  patients  suffering  under  rheumatic  gout.2  It  cannot  be  doubted 
that  Uric  acid  is  formed,  either  directly  or  indirectly,  by  the  metamorphosis 
of  the  protein-compounds,  whether  this  be  consequent  upon  the  disintegration 
of  the  living  tissues,  or  upon  the  decomposition  of  superfluous  alimentary 
materials;  and  we  have  seen  that  there  is  adequate  evidence  that  it  may  be  con- 
verted into  urea  in  the  living  body,  as  in  the  laboratory  of  the  Chemist,  whilst 
there  is  no  corresponding  evidence  that  urea  can  be  converted  into  uric  acid. 
When  it  is  borne  in  mind,  also,  that  uric  acid  is  by  far  the  more  general  of  these 
two  substances — urea  being  almost  peculiar  to  the  Mammalian  class  which  is 
remarkable  for  the  fluidity  of  its  urine,  whilst  uric  acid,  in  combination  with 
soda  and  ammonia,  is  the  characteristic  constituent  of  the  semi-solid  urine  of 
the  oviparous  Yertebrata,  as  well  as  of  that  of  many  Invertebrate  animals3 — 
there  seems  a  strong  probability  that  uric  acid  is  one  of  the  first  products  (if 
not  actually  the  first)  of  that  metamorphosis,  and  that  urea  is  subsequently 
generated  from  it  during  its  passage  through  the  circulation.  That  of  the  entire 
amount  of  uric  acid  generated  in  the  system,  a  part  is  directly  derived  from  the 
food,  when  this  contains  a  superfluity  of  azotized  compounds,  appears  from  the 
experiments  of  Lehmann,  who  found  that  whilst  he  voided  11.24  grains  of  uric 
acid  in  twenty-four  hours,  whilst  living  upon  a  diet  entirely  unazotized — this 
quantity,  therefore,  representing  that  which  results  from  the  "waste"  of  the 
tissues  alone — he  disengaged  15.7  grains  when  living  upon  a  vegetable  diet, 
18.17  grains  upon  a  mixed  animal  and  vegetable  diet,  and  22.64  grains  (or 
rather  more  than  double  the  first  amount)  when  his  diet  was  exclusively  animal. 

1  See  Dr.  Garrod's  Observations  on  certain  pathological  conditions  of  the  Blood  in  Gout, 
Rheumatism,  and  Bright's  Disease,  in  "  Medico-Chirurg.  Trans."  vol.  xxxi. 

2  Op.  cit.  p.  117,  Am.  Ed. 

»  A  substance  termed  Guanine,  which  has  weak  basic  properties,  and  whose  formula  is 
IOC,  6H,  5N,  20,  has  been  discovered  by  linger  in  guano,  which  is  the  mingled  urinary 
and  fecal  excrement  of  sea-fowls ;  it  has  been  recently  discovered  also  in  the  excrements 
of  spiders,  by  Will  and  Gorup-Besanez  ;  and  they  think  it  probable  that  a  substance  which 
they  find  in  the  urinary  organs  of  the  river  craw-fish  and  of  the  fresh-water  mussel,  is 
identical  with  this.  Dr.  J.  Davy  believed  that  the  urinary  secretion  of  scorpions  and  spi- 
ders consists  for  the  most  part  of  xanthine  or  "  uric  oxide,"  (|  66 ;)  but  the  substance  which 
he  discovered  was  more  probably  guanine. 


EXCREMENTITIOUS    SUBSTANCES.  '87 

This,  as  will  hereafter  appear,  is  a  point  of  considerable  importance  in  the  treat- 
ment of  diseases  attended  with  excessive  production  of  uric  acid.  Scarcely  a 
trace  of  uric  acid  has  yet  been  detected  in  the  muscles ;  but  it  has  been  recently 
found  by  Scherer  in  considerable  quantity  in  the  spleen,  where  it  is  accompanied 
by  another  substance  nearly  related  to  it  in  composition,  which  he  has  also  ob- 
tained from  the  heart,  both  of  man  and  of  the  ox.  This  substance,  which  has  been 
termed  Ifypoxanthine,  presents  itself  in  the  form  of  a  white  crystalline  powder, 
which  is  soluble  in  180  parts  of  boiling  water,  but  requires  1090  parts  of  cold 
water  for  its  solution,  so  that  it  is  deposited  on  the  cooling  of  a  decoction  of  the 
substance  of  the  spleen.1  Its  formula  is  50,  2H,  2N,  10;  and  it  thus  con- 
tains 2  equivs.  less  of  oxygen  than  hydrated  Uric  acid,  into  which  it  may  very 
probably  be  metamorphosed. 

58.  Uric  acid  is  almost  uniformly  replaced  in  the  urine  of  herbivorous  animals 
by  an  acid  of  very  different  composition ;  which,  having  been  first  distinguished 
by  Liebig  in  the  urine  of  the  horse,  was  named  by  him  Hippuric  acid.  His 
subsequent  inquiries  satisfied  him  that  it  also  exists  normally,  though  in  com- 
paratively small  quantities,  in  the  urine  of  Man,  especially  after  the  use  of 
vegetable  food ;  and  if  it  is  ever  entirely  absent,  it  is  probably  so  only  when  the 
diet  is  exclusively  animal — just  as  it  is  absent  from  the  urine  of  calves  while 
suckling,  being  replaced  in  them  by  uric  acid.  Hippuric  acid  crystallizes  from 
hot  solutions  in  the  form  of  minute  spangles,  or  of  larger,  obliquely-striated, 
four-sided  prisms,  terminating  at  the  two  ends  in  two  flat  surfaces ;  the  element- 
ary form,  however,  which  is  best  seen  in  crystals  obtained  by  slow  evaporation, 
is  a  vertical  rhombic  prism.  This  acid  is  devoid  of  smell,  has  a  slightly  bitter 
but  not  an  acid  taste,  dissolves  in  400  parts  of  cold  water,  and  very  freely  in 
hot  water,  and  reddens  litmus-paper  powerfully.  Its  formula  is  18C,  8H,  IN, 
50,  +  HO ;  and  it  is  thus  remarkable  for  the  almost  complete  absence  of  nitro- 
gen and  for  the  large  proportion  of  carbon,  a  constitution  which  approximates  it 
closely  to  the  biliary  compounds.  When  boiled  with  concentrated  hydrochloric 
acid,  this  substance  undergoes  a  very  remarkable  change ;  being  resolved  into 
Grlycine  or  gelatin-sugar  (§  33),  and  Benzoic  acid,  probably  in  the  manner  fol- 
lowing, one  additional  equivalent  of  water  being  alone  required. 

C.  H.  N.  0.  C.  H.  N.  0. 

1  equiv.  hydrated  Hipp,  acid  =  189     1     6^1        f   4     5     1     4  =  1  equiv.  Glycine. 
1  equiv.  Water       .         .         =        1  111  14     5  3  =  1  equiv.  Benzoic  acid. 


1810     1     7J        [18  10     1     7 

Various  other  reagents  will  cause  the  production  of  benzoic  acid  at  the  expense 
of  hippuric ;  and  this  change  takes  place  during  the  putrescent  fermentation  of 
urine  of  which  hippuric  acid  is  a  constituent.  According  to  the  view  originally 
suggested  by  Strecker,  hippuric  acid  is  really  to  be  considered  as  a  "  conjugated 
acid,"  formed  by  the  union  of  benzoic  acid,  which  he  supposed  to  pre-exist  in  it, 
with  an  adjunct  composed  of  4C,  H3,  IN,  20,  which  in  separating  takes  to  itself 
an  equiv.  of  water  and  forms  glycine ;  and  this  view  (although  since  abandoned 
by  Strecker  himself)  is  considered  by  Lehmann  as  the  most  probable,  especially 
since  one  of  the  biliary  acids  (§  68)  appears  to  have  an  analogous  constitution, 
glycine  being  there  also  generated  by  the  action  of  acids  upon  it.2  The  close 

1  "Ann.  der  Chem.  und  Pharm.,"  band  Ixxiii.  p.  328. 

2  See  his  "Physiological  Chemistry,"  vol.  i.  pp.  189-192. — The  term  "  conjugated  acid" 
is  applied  to  a  class  of  compounds  recently  discovered,  in  which  certain  organic  acids  unite 
with  other  and  more  basic  bodies  without  losing  anything  of  their  acidity,  still  saturating 
the  same  quantity  of  base  as  if  the  organic  "adjunct"  did  not  exist.     This  adjunct,  which 
follows  the  acid  as  an  integral  constituent  through  all  its  combinations,  exerts  an  essential 
influence  on  its  physical,  and  even  on  many  of  its  chemical  properties.     (Op.  cit.  p.  184.) 


88  CHEMICAL   COMPONENTS    OF   THE   HUMAN   BODY. 

relation  of  Hippuric  to  Benzoic  acid  is  further  indicated  by  the  well-established 
fact,  that  not  only  benzoic  acid,  but  also  the  oil  of  bitter  almonds,  and  cinnamic 
acid,  which  have  the  same  compound  radical  benzoi/l,  are  converted  into  hippuric 
acid  in  the  body.1 

59.  The  remarkable  predominance  of  Carbon  in  Hippuric  acid,  and  its  limita- 
tion to  the  urine  of  animals  which  partly  or  entirely  subsist  on  vegetable  food, 
seem  at  first  sight  to  support  the  idea  of  its  discoverer,  that  it  is  mainly  formed 
at  the  expense  of  the  non-azotized  articles  of  food.  But  this  view  is  directly  op- 
posed by  the  following  facts  stated  by  Prof.  Lehmann  :  In  the  urine  of  patients 
suffering  under  febrile  diseases,  and  taking  but  a  very  small  amount  of  food  of 
any  kind,  the  amount  of  hippuric  acid  in  the  urine  is  increased ;  the  urine  of 
tortoises  which  had  been  kept  fasting  for  more  than  six  weeks,  still  contained 
hippuric  acid;  and  the  urine  of  diabetic  patients  restricted  to  a  purely  animal 
diet  also  exhibits  it.  Further,  it  is  occasionally  to  be  detected,  as  we  learn 
from  Dr.  G.  Bird  (op.  cit.  p.  195),  in  the  urine  of  infants  at  the  breast.  More- 
over, since  it  has  been  ascertained  by  Guckelberger  that  the  azotized  histogenetic 
substances,  when  treated  with  oxidizing  agents,  yield  benzoyl-compounds ;  and 
since  albuminous  as  well  as  gelatinous  substances  yield  glycine  (§  33);  it  would 
appear  highly  probable  that  Hippuric  acid  is  to  be  regarded  as  one  of  the  products 
of  their  decomposition,  and  that  it  is  not  in  any  way  derived  from  non-azotized 
articles  of  food.  The  peculiar  richness  in  carbon  which  distinguishes  this  sub- 
stance is  by  no  means  opposed  to  such  a  view ;  since  an  equal  proportion  is  found 
in  biliary  matters,  and  also  in  the  coloring  matters  of  the  urine,  the  materials 
of  both  of  which  are  unquestionably  derived  in  great  part  from  the  metamorphosis 
of  the  azotized  tissues.  And  when  all  the  facts  of  the  case  are  taken  into  account, 
it  does  not  seem  difficult  to  account  for  the  peculiar  proneness  of  this  acid  to 
appear  in  the  urine  of  herbivorous  animals;  since  the  abundance  of  the  carbona- 
ceous elements  of  their  food  will  tend  to  prevent  the  oxidation  of  the  highly- 
carbonized  products  of  the  waste  of  the  tissues,  and  will  thus  leave  these  to  be 
got  rid  of  through  the  liver  and  kidneys.  And  this  view  derives  confirmation 
from  the  fact,  that  when  stall-fed  animals,  in  whose  urine  hippuric  acid  abounds, 
are  subjected  to  exercise,  the  hippuric  acid  is  more  or  less  completely  replaced 
by  benzoic  acid  which  contains  a  smaller  proportion  of  carbon.  Further,  when 
hippuric  acid  presents  itself  in  unusual  amount  in  states  of  disease,  its  appearance 
is  generally  coincident  with  imperfect  action,  either  of  the  lungs,  skin,  or  liver, 
which  are  the  three  great  emunctories  of  carbonaceous  matters;  so  that  its  pre- 
sence in  the  urine  may  be  considered  as  indicating  that  a  larger  amount  of  car- 
bonaceous matter  is  present  in  the  circulation,  than  the  respiratory  process,  with 
the  cutaneous  and  biliary  excretions,  can  remove.  That  there  is  generally  a 
deficiency  of  urea  in  the  urine,  when  hippuric  acid  makes  its  appearance  in  un- 
usual quantity,  seems  an  additional  indication  that  these  two  substances  are 
derived  from  the  same  ultimate  sources. — Hippuric  acid  has  not  yet  been  detected 
in  Human  blood,  or  in  any  other  secretion  than  the  urinary ;  but  it  has  been 
discovered  in  the  blood  of  the  Ox. 

6j).  Two  substances  have  been  recently  detected  in  the  urine,  which  are  of 
very  considerable  interest,  as  tending  to  connect  the  formation  of  the  components 
of  this  secretion  with  the  disintegration  of  the  azotized  tissues,  more  intimately 

1  It  was  at  one  time  considered,  that  the  hippuric  acid  which  appears  in  the  urine  after 
the  administration  of  the  benzoic,  is  formed  at  the  expense  of  the  uric  ;  and  it  was  proposed 
by  Dr.  A.  Ure  to  administer  benzoic  acid,  when  a  tendency  to  the  increased  production  or 
to  the  precipitation  of  uric  acid  shows  itself  in  the  system,  in  order  that  it  may  be  eliminated 
in  the  more  soluble  form  of  hippuric  acid.  But  the  results  of  analysis  do  not  bear  out  this 
view ;  the  quantity  of  uric  acid  in  the  urine,  after  the  administration  of  benzoic  acid,  not 
showing  any  perceptible  diminution. 


EXCREMENTITIOUS    SUBSTANCES.  89 

than  the  facts  previously  known  appeared  to  justify.  These  substances  are 
termed  Creatine  and  Creatinine^  designations  which  were  conferred  upon  them 
from  their  presence  in  the  "juice  of  flesh/'  of  which  they  are  constant  constitu- 
ents, and  from  which  they  may  be  most  readily  obtained. —  Creatine  is  a  neutral 
substance,  presenting  itself  in  the  form  of  colorless  transparent  crystals,  which, 
when  they  are  deposited  from  a  concentrated  solution,  are  long  and  acicular, 
but  when  formed  more  slowly  are  short  and  thick ;  these  crystals  contain  two 
equivs.  of  water  of  crystallization,  which  they  lose  when  heated  to  112°,  them- 
selves becoming  opaque.  It  is  very  soluble  in  hot  water,  but  requires  74.4 
parts  of  cold  water  to  dissolve  it.  It  is  of  a  bitter,  strongly  pungent  taste ; 
and  irritates  the  pharynx.  Its  formula  is  80,  9H,  3N,  40.  The  proportion 
which  creatine  bears  to  the  whole  mass  of  flesh  is  very  small,  and  is  subject  to 
considerable  variation  in  different  animals,  as  well  as  (probably)  in  different 
states  of  the  same.  Thus  in  1000  parts  of  ox-heart,  Dr.  Gregory  found  from 
1.37  to  1.42  parts  of  creatine  ;  in  the  same  amount  of  the  flesh  of  the  cod,  0.93 
in  one  experiment,  and  1.7  (or  nearly  double)  in  the  other ;  in  the  flesh  of  a 
pigeon,  1.82  parts  ;  and  in  that  of  a  skate  no  more  than  0.60  parts.  It  has  not 
been  detected  in  the  substance  either  of  the  brain,  liver,  or  kidneys ;  and  its 
proportion  in  the  urine  is  so  small  that  this  has  not  yet  been  determined,  its 
place  being  almost  entirely  occupied  by  creatinine.  When  creatine  is  boiled 
with  alkaline  solutions  or  with  baryta-water,  it  is  resolved  into  Urea  and  a  new 
substance  termed  Sarcosine;  and  for  the  reasons  already  given  (§  53),  it  seems 
likely  that  some  such  change  as  that  represented  by  the  following  formula  takes 
place  in  the  living  body : — 

C.  H.  0.  N.        C.  H.  0.  N. 

{2     4    2     2  =  1  equiv.  Urea. 
6714  =  l  "^  Cosine. 
8  11     3     6 

It  is  true  that  Sarcosine  does  not  make  its  appearance,  as  such,  in  the  solids  or 
fluids  of  the  body  ;  but  there  is  reason  to  think  that  it  may  be  rapidly  decom- 
posed, for,  by  the  addition  of  one  equiv.  of  water,  it  would  become  isomeric 
with  lactate  of  ammonia,  and  may  not  impossibly,  therefore,  be  further  reduced 
by  the  respiratory  process,  in  the  same  manner  as  are  the  lactates  generally 
(§  49).  Although  Creatine  dissolves  unchanged  in  dilute  acids,  it  becomes  con- 
verted, by  heating  with  strong  acids,  into  Creatinine,  giving  off  two  equivs.  of 
water.  This  substance,  which  also  forms  prismatic  crystals,  moderately  soluble 
in  water,  differs  considerably  from  creatine  in  its  chemical  relations ;  for  it  has 
a  strong  alkaline  reaction,  even  separating  ammonia  from  its  salts,  and  serves  as 
a  powerful  base  to  acids,  with  which  it  forms  soluble  and  readily  crystallizable 
salts.  It  also  forms  double  salts  with  various  metallic  compounds,  in  a  man- 
ner very  analogous  to  ammonia ;  and  among  these  is  the  white  crystalline  com- 
pound with  chloride  of  zinc,  whose  production  in  the  urine,  upon  the  addition  of 
that  substance,  first  led  to  the  detection  of  creatine  and  creatinine  as  consti- 
tuents of  the  secretion. 

61.  The  relations  of  these  two  substances,  both  chemical  and  physiological, 
pretty  clearly  indicate  that  Creatinine  is  to  be  regarded  as  a  derivative  from 
Creatine  ;  for  whilst  the  latter  predominates  in  the  juice  of  flesh,  almost  to  the 
exclusion  of  the  former,  the  former  predominates  in  the  urine  almost  to  the  ex- 
clusion of  the  latter.  Moreover,  as  we  have  just  seen,  creatinine  may  be  pro- 
duced by  a  very  simple  process  from  creatine ;  and  this  change  takes  place  in 
urine  even  after  it  has  passed  out  of  the  body,  for,  when  putrid,  this  fluid  is  no 
longer  found  to  contain  creatine,  the  whole  of  that  substance  having  undergone 
metamorphosis.  On  the  other  hand,  creatinine  cannot  be  converted  into  crea- 


90  CHEMICAL   COMPONENTS    OF   THE   HUMAN   BODY. 

tine  by  any  known  chemical  process ;  and  there  is  no  evidence  that  such  con- 
version ever  takes  place  in  the  living  body.  Looking,  then,  to  the  nature  of 
creatine  itself,  to  its  relations  to  creatinine  and  to  urea,  and  to  the  fact  that  it  is 
a  constituent  of  urine,  there  can  be  no  doubt  whatever  that,  so  far  from  being 
an  alimentary  substance,  whose  presence  in  the  muscular  tissue  serves  an 
important  purpose  in  nutrition,1  it  is  from  the  first  destined  to  excretion,  and  is 
received  back  into  the  circulation  by  absorption  from  the  muscular  tissue,  to 
be  eliminated  chiefly  under  different  forms,  through  the  kidneys.  As  it  is 
found  so  constantly  in  the  juice  of  flesh,  more  abundantly  in  that  of  wild  and 
hunted  animals  than  in  that  of  tame  and  domesticated  races,  and  most  abund- 
antly of  all  in  the  substance  of  that  never-resting  muscle,  the  heart,  it  may  be 
fairly  presumed  to  be  a  product  of  the  disintegration  of  the  muscular  tissue;  and, 
so  far  as  we  at  present  know,  it  is  the  first  product  of  that  metamorphosis.  Of 
the  mode  in  which  that  change  is  effected,  however,  or  of  the  nature  of  the  com- 
plementary substances  into  which  the  protein-compound  resolves  itself,  we  are 
at  present  entirely  ignorant. 

62.  Some  light  upon  this  last  point,  however,  may  possibly  be  derived  from 
the  study  of  the  other  constituents  of  the  "juice  of  flesh."  In  this  Liebig 
occasionally  detected  an  acid,  to  which  he  has  given  the  name  of  Inosic ;  this 
is  not  crystallizable,  but  forms  a  syrupy  fluid  readily  dissolving  in  water,  and 
possesses  an  agreeable  taste  of  the  juice  of  meat.  It  reddens  litmus  strongly, 
and  forms  crystallizable  salt  with  bases.  Its  formula  is  considered  to  be  IOC, 
6H,  2N,  100+ HO;  and  it  is  thus  remarkable  for  the  large  proportion  of 
oxygen  which-  it  contains.  It  has  not  been  detected  either  in  the  urine  or  in 
any  other  excretion;  and  if  its  absence  in  the  excretory  fluids  should  be  sub- 
stantiated, it  must  evidently  undergo  some  metamorphosis  in  its  passage  from 
the  muscles  to  the  final  outlets  of  the  products  of  their  disintegration.  Dr.  Gr. 
Bird  has  pointed  out  (op.  cit.  p.  37)  that  the  constituents  of  Inosinic  acid  are 
exactly  those  of  Acetic  acid,  Oxalic  acid,  and  Urea ; 

C.   H.  N.  0.          C.  H.  N.  0. 

43  3=1  equiv.  Acetic  acid. 

4  6=2  equivs.  Oxalic  acid. 

1  equiv.  hydrated  Inosinic  acid=  10     7     2  11  =-1    2     4    2  2=1  equiv.  Urea. 


10     7     2  11 

and  suggests  this  as  a  possible  resolution  of  the  first-named  substance,  the  acetic 
and  oxalic  acids  being  carried  off  by  oxidation  through  the  lungs,  and  the  urea 
being  removed  by  the  kidneys.  It  is  some  confirmation  of  this  view,  that  acetic 
acid  has  been  found  by  Scherer  in  the  juice  of  flesh.  Inosinic  acid,  however, 
would  not  appear  to  be  one  of  the  necessary  products  of  the  disintegration  of 
muscle ;  for  it  is  frequently  absent  altogether,  and,  when  it  is  present,  its  quan- 
tity is  very  variable. — Two  other  organic  acids  have  been  observed  by  Liebig 
in  the  juice  of  flesh,  besides  the  lactic  (§  48);  but  little  is  known  of  their  com- 
position. From  his  latest  inquiries,  however,  it  appears  that  the  juice  of  flesh 
immediately  on  being  expressed  has  no  acid  reaction,  but  that  this  very  speedily 
presents  itself  on  exposure  of  the  fluid  to  the  atmosphere ;  from  which  it  may 

1  This  doctrine,  advanced  by  Prof.  Liebig  in  his  important  treatise  on  "  The  Chemistry 
of  Food,"  is  a  specimen  of  the  absurdities  into  which  even  so  eminent  a  Chemist  may  be 
betrayed,  when  he  abandons  that  path  of  purely  chemical  research  in  which  he  is  approached 
by  few,  to  speculate  upon  a  subject  of  which  he  is  comparatively  ignorant,  and  on  which 
the  opinions  of  scientific  Physiologists  have  a  much  higher  claim  to  consideration. — Both 
Chemists  and  Physiologists,  however,  are  now  so  generally  in  accordance  with  regard  to 
the  excrementitious  character  of  Creatine,  that  the  original  doctrine  of  Prof.  Liebig  will 
probably  be  soon  forgotten. 


EXCREMENTITIOUS   SUBSTANCES.  91 

be  inferred  that  these  acids  do  not  originally  exist  in  the  fluid,  but  that  they 
are  formed  there  by  a  fermentation-process  subsequently  to  its  removal  from 
the  body.  The  recent  discovery  of  Inosite,  or  muscle-sugar  (§  46),  appears 
to  afford  a  connecting  link  by  which  we  may  account  for  the  production  of 
lactic  acid  in  this  situation. 

63.  It  will  the  better  serve  to  show  the  remarkable  predominance  of  Nitrogen 
in  nearly  all  of  these  excrementitious  matters  now  described,  if  we  arrange  their 
respective  formulae  in  a  tabular  mode,  and  compare  the  percentages  of  that  ele- 
ment which  they  severally  contain. 

Percentage 
Carbon.  Hydrogen.  Nitrogen.  Oxygen,    of  Nitrogen. 

49           36            6           14  W  «7 

40          31             5           12  }15'67 

2            4            2            2  46.67 

5223  33.33 

18            9             1             6  7.82 

10            7            2          11  15.30 

8546  35.44 

8934  32.06 

8732  37.17 


Urea 

Uric  Acid 

Hippuric  Acid  (hydrated' 

Inosic  Acid  (hydrated) 

Allantoine  (hydrated) 

Creatine 

Creatinine 


Thus  we  see  that  whilst  the  proportion  of  nitrogen  in  Inosic  acid  is  almost  pre- 
cisely the  same  as  in  Albumen,  the  proportion  of  nitrogen  in  Uric  acid,  Allan- 
toine, Creatine,  and  Creatinine,  is  more  than  double  that  which  Albumen  contains, 
whilst  that  of  Urea  is  almost  exactly  triple ;  on  the  other  hand,  the  percentage 
of  nitrogen  in  Hippuric  acid  is  exactly  half  that  which  is  found  in  Albumen. 
Again,  the  percentage  of  carbon  in  Hippuric  acid  (60.33)  considerably  exceeds 
that  which  Albumen  contains  (54.88),  and  is  no  less  than  three  times  as  great 
as  that  which  exists  in  Urea  (20.0). 

64.  Before  quitting  these  characteristic  components  of  the  Urinary  secretion, 
it  will  be  desirable  to  mention  certain  other  organic  substances,  of  which  some 
are  constantly  present  in  it,  whilst  the  occurrence  of  others  is  exceptional  or 
abnormal. — Chemists  have  been  in  the  habit  of  designating,  under  the  general 
term  Extractive  Matters,  substances  which,  whether  they  are  produced  by  the 
reagents  employed,  or  exist  preformed  in  the  animal  fluids,  are  so  deficient  in 
characteristic  properties,  that  they  are  not  capable  of  being  distinguished  by 
analytical  processes,  or  of  being  separated  and  exhibited  in  a  pure  state.  With 
the  progress  of  science,  however,  one  substance  after  another  has  been  with- 
drawn from  this  group ;  thus  by  the  more  attentive  study  of  the  extractive 
matters  of  the  Urine,  creatine,  creatinine,  and  hippuric  acid  have  been  found 
among  its  components ;  and  the  extractive  of  the  Blood  has  already  yielded 
Mulder's  binoxide  and  tritoxide  of  protein  (§  30),  and  will  probably  afford 
many  more  substances  equally  capable  of  being  separately  and  characteristically 
distinguished.  The  Extractive  matters  must  therefore  be  regarded,  according 
to  the  just  remark  of  Lehmann,  as  important  factors  in  the  metamorphosis  of 
animal  tissue,  both  progressive  and  retrograde,  and  deserve  the  most  careful 
and  attentive  Chemical  examination.  Among  the  extractives  of  the  Urine,  have 
been  usually  ranked  the  Coloring  Matters;  the  study  of  which,  for  reasons  enu- 
merated by  Lehinann  (op.  cit.  p.  318),  is  attended  with  peculiar  difficulties.  It 
was  suggested  by  Dr.  Prout  that  two  distinct  pigments  probably  exist ;  and 
this  view  is  to  a  certain  extent  confirmed  by  the  recent  investigations  of  Scherer1 
and  Heller. a  These,  however,  seem  to  indicate  that  there  is  originally  but  a 
single  pigment  (the  uroxanthin  of  Heller),  probably  derived  from  the  haematm 
of  disintegrated  blood-corpuscles  (or  possibly  from  the  pigmentary  matter  of 

1  "Ann.  der  Chem.  tmd  Pharm.,"  band  Ivii.  pp.  180,  195. 

2  "Arch,  fur  Chemie  und  Mikrosk.,"  band  ii.  pp.  161,  173. 


92  CHEMICAL   COMPONENTS   OF   THE   HUMAN   BODY. 

the  nerve-vesicles,  which  may  itself  be  derived  from  the  blood-corpuscles,  §  31)  ; 
but  that  this  pigment  may  be  very  easily  decomposed  into  two  substances,  dif- 
fering in  their  respective  amounts  of  carbon  and  hydrogen.  One  of  these, 
termed  by  Heller  uro-glaucin,  forms  a  dark  blue  powder,  which,  when  dried, 
possesses  a  coppery  lustre  and  dissolves  in  alcohol  with  a  splendid  purple  color. 
The  other  coloring  substance,  which  may  be  generated  by  the  action  of  hydro- 
chloric and  other  acids  upon  the  ordinary  urine-pigment,  is  of  a  yellowish  pink 
hue  when  dissolved  in  alcohol,  and  specially  attaches  itself  to  the  uric-acid  salts, 
which,  when  they  are  deposited  from  the  urine,  carry  it  down  with  them,  just 
as  alumina  carries  down  the  coloring  matter  of  cochineal ;  this  substance  (the 
uro-erythrine  of  Simon,  the  ur-rhodin  of  Heller)  was  long  since  termed  purpu- 
rine1 by  Dr.  Gr.  Bird,  and  by  this  name  it  may  be  most  conveniently  designated. 
The  urine-pigment  as  a  whole  is  remarkable  for  the  large  proportion  of  carbon, 
58£  per  cent.,  which  it  contains;  in  the  purpurine  generated  by  the  action  of 
hydrochloric  acid  on  urine,  the  proportion  of  carbon  is  62 £  per  cent.;  but  in 
the  urine  of  patients  suffering  under  febrile  disorders  or  organic  disease  of  the 
liver,  in  which  a  very  large  amount  of  purpurine  exists,  and  in  which  bile-pig- 
ment (a  still  more  highly  carbonized  substance,  §  70)  is  very  commonly  present 
likewise,  the  proportion  of  carbon  has  been  found  to  rise  even  to  65f  per  cent. 
The  pathological  conditions  under  which  the  amount  of  this  carbonaceous  pig- 
ment increases,  are  such  as  to  indicate  that  the  elimination  of  carbon  by  the 
liver,  lungs,  and  skin  is  not  being  performed  with  its  due  activity ;  and  the 
superfluity  is  thus  thrown  upon  the  kidneys  for  excretion.3 — There  seems  no 
doubt  that  even  normal  Urine  contains  Sulphur  in  an  unoxidized  state ;  and 
the  inquiries  of  Prof.  Ronalds  have  led  him  to  the  conclusion  that  this  element, 
together  with  a  small  quantity  of  Phosphorus,  is  contained  in  a  peculiar  com- 
pound which  forms  part  of  the  so-called  "  extractive."  This  compound  has  not 
yet  been  obtained  in  a  separate  form;  but  it  furnishes  the  medium  for  the  eli- 
mination of  from  at  least  3  to  5  grains  of  sulphur  in  the  twenty-four  hours. 
The  sulphur  and  phosphorus  set  free  by  the  disintegration  of  the  albuminous 
tissues,  are  for  the  most  part  oxidated  in  the  system,  and  carried  out  of  it  in  the 
form  of  sulphuric  and  phosphoric  acids,  in  union  with  bases.  But,  as  we  shall 
hereafter  see  (§  69),  a  provision  exists  in  the  biliary  excretion,  for  carrying  off 
a  large  amount  of  sulphur  in  an  unoxidized  state;  and  it  would  appear  as  if  the 
urine  became  the  vehicle  for  whatever  unoxidized  sulphur  may  remain  to  be 
eliminated.  The  normal  presence  of  this  sulphur-extractive  in  the  urine  has 
an  interesting  relation  to  the  occasional  or  abnormal  occurrence  of  the  highly 
sulphurized  substance  known  as  Cystine  (§  66). 

65.  Among  the  organic  compounds  whose  occurrence  in  Human  urine  is 
abnormal,  we  may  first  mention  Xanihine,  or  Uric  oxide,  which  is  a  very  rare 
constituent  of  calculi  and  of  sedimentary  deposits.  This  seems  to  be  a  neutral 
substance,  having  no  action  on  vegetable  colors,  and  not  being  yet  known  to 
enter  into  combination  with  either  acids  or  alkalies.  When  freshly  precipitated, 
it  presents  itself  as  a  white  powder,  which  is  neither  crystalline  nor  gelatinous; 
and,  when  dried,  it  forms  pale,  yellowish,  hard  masses,  which,  on  being  rubbed, 
assume  a  waxy  brightness.  The  calculi  composed  of  this  substance  closely 
resemble  those  formed  of  uric  acid,  for  which  they  are  generally  mistaken ;  they 
may  be  distinguished,  however,  by  the  well-marked  salmon  or  rather  cinnamon 
tint  presented  by  their  sections,  and  by  the  insolubility  of  their  substance  in  a 

1  It  is  important  to  bear  in  mind  that  this  substance  has  no  relation  whatever  to  murex- 
ide  (§  55),  which  was  termed  purpurate  of  ammonia  by  Dr.  Prout,  under  the  influence  of  an 
erroneous  view  of  its  constitution. 

2  See  Dr.  Golding  Bird's  "Urinary  Deposits,"  pp.  146-148,  Am.  Ed.,  and  CHAP.  xn. 
SECT.  3,  of  the  present  volume. 


EXCREMENTITIOUS    SUBSTANCES.  93 

weak  solution  of  carbonate  of'  potass,  which  dissolves  uric  acid.1  It  is  soluble, 
however,  in  the  fixed  alkalies  and  ammonia,  as  also  in  nitric  and  sulphuric 
acids.  As  no  compounds  have  yet  been  obtained,  by  which  its  combining 
equivalent  can  be  determined,  the  formula  50,  211,  2N,  20,  must  be  con- 
sidered as  representing  nothing  more  than  the  percentage  composition  of  its 
elements ;  and,  although  this  only  differs  from  that  of  hydrated  Uric  acid  in  the 
want  of  a  single  equiv.  of  oxygen,  yet  all  attempts  to  generate  either  from  the 
other,  or  to  obtain  urea  from  uric  oxide,  have  hitherto  failed.  So,  also,  it  seems 
to  differ  from  Hypoxanthine  (§  57)  only  in  containing  one  more  equiv.  of  oxy- 
gen ;  but  no  real  relation  has  been  shown  to  exist  between  these  substances. — 
Of  the  conditions  under  which  Xanthine  is  formed  in  the  living  body,  it  is  im- 
possible at  present  to  form  the  slightest  idea.  Strahl  and  Lieberkiihn  believe 
that  they  have  discovered  it  in  ordinary  Human  urine ;  but  the  substance  which 
they  describe  seems  rather  to  be  Guanine  (§  57,  note),  which,  when  first  dis- 
covered, was  mistaken  for  Xanthine,  but  which  differs  from  it  in  composition 
and  properties,  and  is  readily  distinguished  from  it  by  its  solubility  and  hydro- 
chloric acid.  Guanine  is  a  yellowish-white  crystalline  powder,  devoid  of  odor 
or  taste,  insoluble  in  water,  and  having  no  action  on  vegetable  colors;  it  serves, 
however,  as  a  base  to  acids,  though  its  salts  are  very  unstable ;  and  its  formula 
is  IOC,  5H,  5N,  20+ HO.  Guanine  appears,  from  the  researches  of  Will 
and  Gorup-Besanez,3  to  be  one  of  the  characteristic  constituents  of  the  urinary 
secretion  in  Invertebrated  animals ;  and,  if  it  should  prove  to  be  of  constant 
or  even  of  frequent  occurrence  in  Human  urine,  the  fact  will  be  one  of  no 
little  interest.  No  doubt  can  be  entertained,  that  Xanthine  and  Guanine  are 
both  of  them  to  be  regarded  as  products  of  the  metamorphosis  of  the  azotized 
tissues. 

66.  A  substance  is  occasionally  found  in  Urinary  calculi,  and  also  in  sedi- 
mentary deposits,  which  is  remarkable  for  the  large  proportion  of  Sulphur — 
amounting  to  26.66  per  cent. — included  in  its  composition.  The  substance, 
termed  Cystine,  occurs  in  the  form  of  colorless,  transparent,  hexagonal  plates  or 
prisms,  is  devoid  of  taste  or  smell,  is  insoluble  in  water  and  alcohol,  and  has  no 
action  on  vegetable  colors ;  but  it  serves  as  a  base  to  oxalic  and  the  mineral 
acids,  forming  with  them  saline  combinations,  most  of  which  are  crystallizable. 
Its  formula  is  6C,  6H,  IN,  2S,  40 ;  but  no  probable  account  can  yet  be 
given  of  the  mode  in  which  these  equivalents  are  combined  and  arranged.  It 
is  very  readily  soluble  in  ammonia,  but  forms  no  compound  with  it,  so  that  on 
the  evaporation  of  the  ammonia  it  crystallizes  in  its  characteristic  tablets;  and 
by  this  character,  as  well  as  by  the  peculiar  and  disagreeable  odor  which  it 
emits  in  burning  when  heated  on  platina-foil,  cystine  may  be  readily  distin- 
guished from  any  other  urinary  sediment.  Though  its  occasional  presence  in 
urine  has  not  been  noticed  by  many  observers,  yet  it  would  appear  sometimes 
to  exist  there  in  considerable  quantity,  forming  a  nearly  white  or  pale  fkwn- 
colored  pulverulent  deposit,  much  resembling  the  pale  variety  of  urate  of  am- 
monia, for  which  it  is  liable  to  be  mistaken ;  and  so  copious  may  this  be,  that 
Dr.  G.  Bird  states  that  he  has  seen  a  6  oz.  bottle  full  of  urine  let  fall  by  repose 
a  sediment  of  cystine  to  the  depth  of  half  an  inch.  According  to  this  excellent 
observer,  the  presence  of  cystine  in  the  urine  may  often  be  detected  by  micro- 
scopic examination,  where  it  forms  no  distinct  deposit ;  and  this  especially  in 
strumous  subjects,  a  class  which  he  regards  as  peculiarly  subject  to  cystin-urea. 
It  has  also  been  observed  in  chlorotic  subjects.  There  can  be  no  doubt  that 
cystine  is  one  of  the  forms  under  which  the  products  of  the  metamorphosis  of 
the  albuminous  tissues  present  themselves ;  and  its  composition  is  not  so  far 

1  See  Dr.  Golding  Bird's  "Urinary  Deposits,"  pp.  138-142,  Am.  Ed. 

2  "Ann,  der  Chem.  u.  Pharm.,"  band  Ixix.  p.  117. 


94  CHEMICAL   COMPONENTS   OF   THE   HUMAN   BODY. 

removed  from  that  of  the  ordinary  results  of  that  metamorphosis,  as  would  at 
first  sight  appear.     For,  as  Dr.  G.  Bird  has  pointed  out, 

C.    H.  N.  0.  S.  C.  H.   N.  0.  S. 


4eqs.Urea  .  .  .=24220 
2  eqs.  Hydrated  Uric  Acid  .  =10  4460 
4  eqs.  Sulphuretted  Hydrogen  =4  4 

12  12    6    8    4 


12  12     2     8     4=2  eqs.  Cystine. 
4  =4  eqs.  Nitrogen. 


12  12     6     8     4 


It  is  a  very  remarkable  circumstance  that  the  composition  of  Cystine  should 
present  an  extremely  close  relation  to  that  of  Taurine,  the  sulphurized  consti- 
tuent of  the  bile  (§  69) ;  their  respective  percentages  of  hydrogen,  nitrogen, 
and  sulphur  being  almost  precisely  identical,  and  the  difference  lying  only  in 
those  of  carbon  and  oxygen ;  as  will  be  seen  from  the  following  comparison : — 

Cystine.  Taurine. 

Carbon       ^  ,..,.,,,*,    ;  :.,.:;,-       .     30.00  19.20 

Hydrogen.       ,.'"      i-.  ',-•..,    .,.  *.     ^       .       5.00  5.60 

Nitrogen     .         '..    "  ."      .        '."'.,"       .     11.66  11.20 

Oxygen       .    '    .''•;"    !  .       ' .  "     .'        .     26.67  38.40 

Sulphur      .<    :<".  =  •>••   V';r  &*  *'> -:':   '."       .     26.67  25.60 


100.00  100.00 

Here,  then,  we  have  another  marked  example  of  the  vicarious  nature  of  the 
urinary  and  biliary  excretions ;  the  former  taking  upon  itself  the  removal, 
under  peculiar  circumstances,  of  a  product  whose  components  should  normally 
find  their  way  into  the  latter.1 

67.  We  now  pass  from  that  group  of  Excretory  matters  of  which  Nitrogen  is 
the  predominating  constituent,  to  that  of  which  Carbon  and  Hydrogen  are  the 
principal  components;  and  as  the  former  are  the  characteristic  ingredients  of 
the  Urinary  excretion,  so  are  the  latter  of  the  Biliary.     Regarding  the  organic 
compounds  we  have  now  to  consider,  however,  our  knowledge  is  far  less  definite 
and  satisfactory  than  it  is  respecting  those  which  have  been  already  passed  in 
review ;   and  this  arises  from  several  causes,  among  which  may  be  more  par- 
ticularly mentioned  the  great  facility  with  which  they  are  decomposed,  both 
spontaneously,  and  by  the  operation  of  reagents ;  so  that  it  is  by  no  means  easy 
to  say,  in  many  instances,  whether  a  given  substance,  extracted  from   the  bile 
by  analytical  operations,  pre-existed  in  it,  or  has  been  subsequently  formed 
under  the  treatment  to  which  that  fluid  has  been  subjected.     There  has,  conse- 
quently, been  a  vast  discrepancy  of  opinion  amongst  Chemists,  with  regard  to 
the  constitution  of  this  excretion ;  some  having  regarded  as  original  components, 
what  others  have  considered  as  secondary ;  and  the  number  of  proximate  con- 
stituents having  been  ranked  high  by  some,  whilst  others  have  reduced  it  to  no 
more  than  four  or  five. — According  to  Strecker,  whose  researches  have  been 
more  successful,  and  whose  views  seem  more  trustworthy,  than  those  of  any 
other  chemist,  we  are  to  regard  the  proper  biliary  matter  as  chiefly  composed 
of  two  substances,  which  are  regarded  by  Lehmann   as  "  conjugated  acids" 
(§  58,  note),  formed  by  the  union  of  one  and  the  same  acid,  the  true  Cholic^ 
with  Glycine  and  Taurine  respectively,  and  hence  termed  by  him  the  Glyco- 
cholic  and  the  Taurocholic. 

68.  This  Clwlic  acid  (the  cTiolalic  of  Strecker),  which  was  first  obtained  in  a 
state  of  purity  by  Demargay,  is  a  fatty  or  rather  a  resinous  acid,  from  which 
nitrogen  is  altogether  absent,  whilst  oxygen  is  present  in  it  in  only  a  small 
proportion,  its  formula  being   48C,  39H,  90.     It  forms  tetrahedral   or  more 

1  See,  on  the  whole  of  this  subject,  the  excellent  treatise  of  Dr.  Golding  Bird  on  "Uri- 
nary Deposits,"  already  referred  to. 


EXCREMENTITIOUS   SUBSTANCES.  95 

rarely  square  octohedral  crystals,  which  effloresce  on  exposure  to  the  air ;  it  is 
soluble  in  750  parts  of  boiling  water,  and  in  4000  parts  of  cold,  and  dissolves 
very  readily  in  alcohol,  especially  when  heated.  Its  taste  is  bitter,  leaving  a 
faint  sweetish  after-taste.  It  fuses  at  383°;  if  heated  above  that  temperature, 
it  loses  its  atom  of  basic  water,  and  is  converted  into  choloidic  acid;  and  if 
heated  to  554°,  it  becomes  converted  into  dysli/sin,  a  resinous  substance  having 
no  acid  properties.  These  changes  may  also  be  effected  by  boiling  cholic  acid 
with  hydrochloric  acid.  The  acid  reaction  of  this  substance  is  sufficiently  strong 
to  redden  litmus,  and  to  enable  it,  with  the  aid  of  heat,  to  expel  the  carbonic 
acid  from  solutions  of  the  alkaline  carbonates.  The  salts  which  it  forms  possess 
a  bitter,  and  at  the  same  time  a  slightly  sweet  taste ;  they  are  all  soluble  in 
alcohol,  but  water  dissolves  only  the  cholates  of  the  alkalies  and  of  baryta. 
The  salts  of  choloidic  acid  are  perfectly  isomeric  with  those  of  cholic  acid ;  but 
it  is  curious  that  the  former  acid  is  displaced  even  by  carbonic  acid,  although 
with  the  aid  of  heat  it  decomposes  the  carbonates.  Cholic  acid  may  be  recog- 
nized wherever  it  occurs — whether  combined  with  its  adjuncts  as  a  conjugated 
acid,  or  metamorphosed  into  the  choloidic — by  the  excellent  test  devised  by 
Pettenkofer,  founded  upon  its  peculiar  reaction  with  sugar  and  sulphuric  acid ; 
for  if,  to  the  fluid  suspected  to  contain  bile,  there  be  first  added  a  little  solution 
of  sugar,  and  pure  sulphuric  acid  be  then  added  by  drops,  a  yellowish  color  is 
produced,  deepening  to  a  pale  cherry,  then  to  a  carmine,  and  lastly  to  an  intense 
violet  tint,  if  bile  be  present.  This  test  may,  therefore,  be  applied  to  determine 
the  presence  or  absence  of  the  characteristic  components  of  bile ;  and  we  shall 
hereafter  notice  some  of  the  results  of  its  application.  When  choloidic  acid  is 
distilled  with  nitric  acid,  it  yields  the  volatile  acids  of  the  butyric  and  succinic 
acid  groups,  as  does  also  oleic  acid  under  similar  treatment ;  and  it  has  been 
recently  pointed  out  by  Schultze,1  that  oleine,  when  submitted  to  the  bile-test, 
presents  nearly  the  same  reaction  as  bile ;  so  that  a  special  relation  seems  to 
exist  between  them.  Cholic  acid  does  not  naturally  occur  in  its  isolated  state, 
and  can  only  be  obtained  by  processes  that  have  the  effect  of  separating  it  from 
the  nitrogenous  substances  with  which  it  is  normally  conjugated. — The  com- 
pound of  Cholic  acid  and  Grlycine  (§  33),  termed  by  Lehmann  Glycocholic  acid, 
but  formerly  known  par  excellence  as  the  bilic  or  cholic  acid,  is  the  principal 
organic  constituent  of  the  bile  of  most  animals ;  being  united  in  that  fluid  with 
potash  and  soda  as  bases,  and  not  having  a  sufficiently  strong  acidity  to  prevent 
its  salts  from  possessing  an  alkaline  reaction.  This  acid  crystallizes  in  extremely 
delicate  needles,  which  remain  unchanged  at  277°;  it  has  a  bitterish-sweet  taste, 
dissolves  in  120.5  parts  of  hot  water,  and  303  of  cold,  and  is  readily  soluble  in 
spirit.  By  prolonged  boiling  with  alkalies  or  baryta-water,  it  is  resolved  into 
cholic  acid  and  glycine ;  whilst,  if  boiled  with  concentrated  sulphuric  or  mu- 
riatic acids,  it  is  resolved  into  choloidic  acid  and  glycine.  Its  alkaline  salts, 
which  form  "  crystallized  bile,"  are  very  soluble  both  in  water  and  spirit, 
and  separate  from  their  alkaline  solutions  on  the  addition  of  ether,  in  large 
glistening  white  clusters  of  radiating  needles,  resembling  wavellite.  These 
burn,  when  heated,  with  a  bright  smoky  flame.  The  formula  of  this  acid  is 
52C,  42H,  N,  110 -f  HO;  and,  with  the  addition  of  another  equivalent  of  water, 
is  exactly  that  of  cholic  acid  -f-  glycine. 

69.  The  other  conjugated  acid  of  bile,  termed  by  Lehmann  the  Taurocholic 
(but  also  named  choleic  acid,  and  formerly  known  as  bilin),  has  not  yet  been 
separated  in  a  state  of  perfect  purity,  that  is  to  say,  free  from  glycocholic  acid ; 
it  cannot  be  obtained  in  a  crystalline  state,  and  it  is  more  soluble  in  water  than 
glycocholic  acid,  whilst  its  acid  properties  are  far  weaker.  It  dissolves  fats, 
fatty  acids,  and  cholesterin  in  large  quantities;  and  is  thus  the  cause  why  glyco- 

•  Canstatt's  "Jahresbericlit,"  1850,  p.  101. 


96  CHEMICAL   COMPONENTS    OF  THE    HUMAN   BODY. 

cholic  acid  is  not  precipitated,  when  acids  are  added  to  fresh  bile.  When  boiled 
with  alkalies,  it  is  resolved  into  taurine  and  cholic  acid ;  and  when  boiled  with 
the  mineral  acids,  into  taurine  and  choloidic  acid.  Its  formula,  as  deduced  from 
the  composition  of  its  salts,  is  52C,  45H,  IN,  2S,  140;  and  this,  with  an 
additional  equivalent  of  water,  corresponds  to  cholic  acid  +  taurine.  The  alka- 
line taurocholates,  which  are  the  forms  under  which  this  acid  exists  in  the  bile, 
dissolve  readily  in  water  and  alcohol ;  they  have  no  reaction  on  vegetable  colors, 
and  have  a  sweet  taste  with  a  bitter  after-taste ;  when  heated,  they  melt  and 
burn  with  a  bright  smoky  flame.  Although  they  may  be  kept  for  some  time 
in  solutions  exposed  to  the  air,  without  decomposition,  provided  they  be  pure, 
yet  they  are  very  readily  affected  by  the  presence  of  certain  nitrogenous  sub- 
stances, such  as  mucus;  and  taurine  is  then  set  free,  with  alkaline  cholates  and 
choloidates. — The  substance  now  designated  Taurine  (formerly  known  as  biliary 
asparagine)  is  a  very  peculiar  neutral  compound,  which  crystallizes  in  colorless, 
regular,  hexagonal  prisms,  with  four  and  six-sided  sharp  extremities.  It  is 
hard,  craunches  between  the  teeth,  has  a  cooling  taste,  resists  the  action  of  the 
atmosphere,  dissolves  in  15  £  parts  of  water  and  573  of  dilute  alcohol,  and  has 
no  action  on  vegetable  colors.  It  dissolves,  without  undergoing  change,  even 
at  the  boiling  point,  in  the  mineral  acids,  but  forms  no  compounds  with  them ; 
hence  it  cannot  be  properly  considered  as  a  base. .  The  most  remarkable  peculi- 
arity in  its  composition  is  the  large  proportion  of  Sulphur  which  it  contains, 
this  amounting  to  25.6  per  cent. ;  and  yet,  notwithstanding  that  this  substance 
had  been  analyzed  by  Grmelin,  Demar§ay,  Pelouze,  and  Dumas,  the  presence  of 
this  element  was  overlooked,  until  it  was  discovered  by  Redtenbacher.1  It  may 
be  made  evident  by  the  development  of  sulphurous  acid,  when  taurine  is  in- 
flamed in  air;  and  in  this  manner,  when  the  presence  of  one  of  the  conjugated 
biliary  acids  has  been  detected  by  Pettenkofer's  test,  it  may  be  determined  to 
be  the  tauro-cholic.  When  taurine  is  boiled  with  caustic  potash,  it  develops 
ammonia,  and  leaves  a  residue  consisting  solely  of  sulphurous  and  acetic  acids 
in  combination  with  potash.  It  is  thought  probable  by  Lehmann,  that  the 
sulphur  of  Taurine  already  exists  in  an  oxidized  condition,  since  it  cannot  be 
recognized  in  this  substance  by  any  of  the  ordinary  fluid  oxidizing  agents. 
Taurine  has  never  been  found  in  an  isolated  state  in  healthy  bile,  although,  as 
just  now  pointed  out,  it  is  set  free  by  the  spontaneous  decomposition  of  the 
tauro-cholates.  It  must  undoubtedly  be  regarded  as  one  of  the  products  of  the 
metamorphosis  of  the  albuminous  tissues ;  but  of  the  mode  in  which  it  is  gene- 
rated, no  account  whatever  can  be  given. 

70.  The  coloring  matter  of  the  Bile,  or  Bile-pigment,  is  a  substance  pecu- 
liarly difficult  to  investigate  satisfactorily,  owing  especially  to  the  very  small 
quantity  in  which  it  occurs,  and  to  its  extreme  instability.  The  most  frequent 
form  under  which  it  presents  itself,  is  that  of  a  brown,  non-crystalline  powder, 
devoid  of  taste  and  smell,  insoluble  in  water,  very  slightly  soluble  in  ether,  and 
more  so  in  alcohol,  to  which  it  communicates  a  distinct  yellow  tint ;  this  sub- 
stance, the  cholepyrrhin  of  Berzelius,  the  Mliphaein  of  Simon,  constitutes  a 
large  part  of  most  biliary  calculi,  in  which,  however,  it  exists  in  a  state  of  inso- 
luble combination  with  lime.  When  it  is  dissolved  in  alkaline  solutions,  these, 
which  are  at  first  of  a  clear  yellow,  become,  by  exposure  to  the  air,  of  a  greenish- 
brown  tint;  and  it  is  on  this  modification,  the  consequence  probably  of  a  higher 
oxidation,  that  the  well-known  changes  of  color  which  occur  in  some  of  the 
animal  fluids  are  dependent.  The  yellow  alkaline  solution,  when  treated  with 
nitric  acid,  becomes  first  green,  then  blue  (which  hue,  however,  can  hardly  be 
detected  in  consequence  of  its  rapid  transition  into  violet),  and  then  red ;  after 
a  considerable  period,  the  red  again  passes  into  a  yellow  color,  but  the  nature 

1  "Ann.  der  Chem.  und  Pharm.,"  band  Ivii.  pp.  170-174. 


EXCREMENTITIOUS   SUBSTANCES.  97 

of  the  substance  is  then  entirely  changed.  When  the  yellow  alkaline  solution 
is  treated  with  hydrochloric  acid,  the  pigment  is  precipitated  with  a  green  tint ; 
this  precipitate  forms  a  red  solution  with  nitric  acid,  and  a  green  solution  with 
the  alkalies,  and  appears  to  be  perfectly  identical  with  the  green  modification  of 
bile-pigment.  When  acids  are  added  to  fresh  bile,  a  green  color  is  produced, 
if  oxygen  be  present,  but  not  if  it  be  excluded.  Bile-pigment  is  occasionally 
found  in  the  urine  in  large  quantities,  when  its  secretion  by  the  natural  channel 
is  prevented ;  and  it  may  be  readily  recognized  by  the  nitric  acid  test.  There 
is  much  uncertainty  in  regard  to  the  precise  composition  of  this  substance,  for 
the  reasons  already  specified;  the  analyses  which  have  been  made  of  it,  however, 
indicate  that  it  is  remarkable  for  the  enormous  proportion  of  carbon  which  it 
contains,  this  being  as  much  as  68  per  cent.,  and  thus  exceeding  the  proportion 
of  that  element  in  the  black  pigment  of  the  eye,  and  in  abnormal  melanic  de- 
posits; it  contains  also  about  8  per  cent,  of  nitrogen. — The  bile  of  the  Ox 
contains  a  green  pigment  which  seems  to  be  distinct  from  the  preceding,  not 
undergoing  changes  of  color  when  treated  with  nitric  acid,  and  containing  little 
or  no  nitrogen ;  this  was  considered  by  Berzelius  to  be  identical  with  the  chloro- 
phyll of  plants,  and  was  designated  by  him  as  biliverdin;  it  does  not  seem, 
however,  to  be  present  in  human  bile.  Another  pigmentary  substance  has  been 
discovered  in  bile,  however,  which  is  distinguished  by  its  crystalline  form,  and 
by  its  reddish-yellow  hue ;  this  was  named  by  Berzelius  bilifulvin. — The  source 
of  these  coloring  matters  is  probably  to  be  looked  for,  as  already  pointed  out 
(§  31),  in  the  hsematin  of  the  red  corpuscles ;  which  undergoes  changes,  after 
their  disintegration  has  commenced,  that  show  a  decided  approximation  to  them. 
And  it  is  a  most  important  confirmation  of  this  view,  that  hsematin,  when 
effused  in  situations  where  it  can  be  acted  on  by  the  air,  exhibits  most  of  the 
shades  of  color  which  have  been  mentioned  as  characteristic  of  biliphaein ;  as 
is  seen  in  the  ordinary  case  of  a  cutaneous  ecchymosis.  With  regard  to  the 
place  in  which  the  actual  transformation  occurs,  however,  we  are  entirely  igno- 
rant; for  although  bile-pigment  frequently  shows  itself  in  large  quantities  in  the 
blood,  and  is  deposited  by  it  in  the  tissues  and  fluids,  saturating  the  bones, 
teeth,  cartilages,  ligaments,  fibrous  tissues  (being  especially  evident  in  the  scle- 
rotic coat  of  the  eye,  and  in  the  skin),  showing  itself  also  in  the  nerves,  the 
crystalline  lens,  and  the  vitreous  humor,  and  more  or  less  tinging  all  the  secre- 
tions and  exudations  into  which  the  fluid  of  the  blood  passes ;  yet  this  may 
fairly  be  attributed,  as  we  shall  presently  see,  to  the  reabsorption  of  the  pigment 
subsequently  to  its  elimination  by  the  liver  (§  71).  And  looking  to  the  general 
physiological  relations  of  this  organ,  hereafter  to  be  pointed  out,  we  may  surmise, 
without  improbability,  that  it  is  by  its  agency  that  the  transformation  is  effected, 
and  that  the  bile-pigments  do  not  pre-exist  as  such  in  the  blood. 

71.  With  regard  to  the  source  of  the  various  components  of  the  Biliary  ex- 
cretion which  have  been  now  described,  our  information  is  much  less  precise 
than  it  is  with  respect  to  the  principal  excretory  matters  of  the  Urine.  This 
arises,  not  merely  from  the  difficulties  already  adverted  to  as  attending  the 
chemical  determination  of  the  true  constituents  of  Bile ;  but  also  from  the  fact 
that  the  detection  of  their  presence  in  the  blood  by  no  means  implies  their  pre- 
existence  in  the  circulating  fluid.  For,  as  we  shall  hereafter  see  (CHAP.  Vii.), 
there  is  strong  reason  to  believe  that  a  considerable  proportion  of  the  solid  mat- 
ters of  the  bile,  which  are  poured  into  the  upper  part  of  the  intestinal  tube,  are 
normally  reabsorbed,  and  again  introduced  into  the  current  of  the  circulation, 
before  reaching  the  outlet ;  and  it  is  quite  certain  that  such  reabsorption  may 
take  place  in  cases  of  obstruction  in  the  biliary  ducts,  when  the  bile  is  secreted, 
but  cannot  find  its  way  into  the  alimentary  canal.  Hence,  neither  the  detection 
of  cholic  acid  in  the  blood  by  Pettenkofer's  test — which  has  been  occasionally 
accomplished,  even  in  cases  of  disease  in  which  the  liver  did  not  seem  impli- 


CHEMICAL   COMPONENTS   OF   THE   HUMAN   BODY. 

cated,  though  never  in  perfect  health — nor  its  detection  in  the  urine  or  in  va- 
rious fluids  exuded  from  the  blood,  affords  the  least  evidence  that  it  was  pre- 
formed there ;  any  more,  indeed,  than  does  the  accumulation  of  the  coloring 
matter  which  makes  its  presence  so  obvious  in  jaundice.  Of  that  evidence 
which  is  furnished  in  the  case  of  the  urine,  by  the  detection  of  some  of  its  cha- 
racteristic components  in  the  tissues  which  undergo  most  rapid  disintegration, 
we  have  here  a  most  complete  deficiency ;  for  no  trace  of  the  biliary  acids  has 
yet  been  found  in  the  tissues,  except  under  circumstances  which  justify  the 
belief  that  these  substances  were  deposited  there.  The  only  distinct  indication 
yet  obtained,  that  the  characteristic  components  of  bile  are  preformed  in  the 
blood  (Cholesterine  being  scarcely  to  be  reckoned  as  such),  is  afforded  by  the 
experiments  of  Kunde,  one  of  the  pupils  of  Lehmann ;  who  demonstrated,  by 
Pettenkofer's  test,  the  presence  of  biliary  matters  in  the  blood  of  frogs  whose 
livers  had  been  extirpated.  On  the  other  hand,  there  is  much  that  indicates,  if 
it  does  not  prove,  that  the  function  of  the  liver  is  not  the  mere  selection  and 
elimination  of  the  elements  of  bile  from  the  blood ;  but  that  it  exercises  a  most 
important  transforming  power,  both  over  the  constituents  of  the  blood,  and 
over  those  of  the  bile.  Of  the  evidence  which  has  been  lately  adduced  in  proof 
of  the  first  of  these  positions,  some  notice  has  already  been  taken  (§§  40,  46) ; 
and  that  of  the  second  will  be  more  appropriately  considered  hereafter  (CHAP. 
xn.  SECT.  2).  At  present  it  will  be  sufficient  to  remark,  that,  whilst  a  chemi- 
cal comparison  of  the  elements  of  the  Bile  and  Urine  shows  that  each  of  these 
excretions  is  (so  to  speak)  the  complement  of  the  other,  and  that  the  mass  of 
the  blood  or  of  the  solid  tissues  might  resolve  itself  into  these  two  sets  of  com- 
pounds (§  91),  various  physiological  and  pathological  phenomena  seem  to  indi- 
cate, that  the  products  of  the  metamorphosis  of  the  tissues  which  afterwards 
become  the  components  of  bile,  do  not  take  the  form  of  those  components  until 
they  have  been  acted  on  by  the  liver,  and  reduced  to  a  state  comparatively  innox- 
ious. For  whilst  there  is  abundant  evidence  that  the  constituents  of  bile,  both  its 
resinous  acids,  and  its  coloring  matter,  may  be  reabsorbed  without  serious  injury; 
and  whilst  there  is  strong  reason  to  believe  that,  as  regards  the  resinous  acids,  such 
reabsorption  is  habitual;  there  is  adequate  proof,  on  the  other  hand,  that  the  reten- 
tion within  the  circulating  current  of  the  matters  from  which  bile  is  formed,  owing 
to  structural  disease  or  functional  inactivity  of  the  liver,  is  attended  with  the  most 
serious  consequences,  and  will,  if  prolonged,  induce  a  fatal  result. — It  is  surmised 
by  Lehmann,  in  consequence  of  the  resemblance  already  pointed  out  between  the 
cholic  and  oleic  acids,  that  bile  is  partly  formed  from  the  fatty  matters  of  the 
system ;  but  there  is  no  adequate  proof  of  this ;  and  as  we  have  seen  that  fatty 
matters  may  themselves  be  formed  by  the  metamorphosis  of  albuminous  sub- 
stances (§  40),  there  seems  no  reason  to  dissent  from  the  usually  received  opin- 
ion, that  the  chief  source  of  biliary  matter  is  ultimately  to  be  found  in  the  dis- 
integration of  the  azotized  tissues. 

6.  Inorganic  Substances  forming  part  of  the  Living  Body,  and  contained  in  its 

Excretions. 

72.  Although  it  might  have  been  supposed  that  the  Chemist  would  have  had 
comparatively  little  difficulty  in  determining  what  are  to  be  regarded  as  the  In- 
organic or  Mineral  constituents  of  the  body,  yet  the  attainment  of  a  precise 
knowledge  of  them  is  attended  with  peculiar  difficulties,  arising  out  of  the  mode 
in  which  these  constituents  are  blended  with  Organic  compounds.  The  usual 
method  of  determining  their  presence,  nature,  and  amount,  has  been  to  incine- 
rate the  dried  tissue  or  the  solid  residue  of  the  fluid,  and  to  analyze  the  ash 
which  remains  ;  but  this  process,  as  Prof.  Lehmann  justly  remarks,  gives  us  no 
information  with  regard  to  the  combinations  in  which  the  constituents  of  that 


INORGANIC   SUBSTANCES.  99 

ash  occurred  in  the  organic  substance.  Thus,  to  take  a  simple  example,  nothing 
can  be  certainly  made  out  from  it  with  regard  to  the  presence  of  lactic  acid, 
since  all  the  lactates  are  reduced  by  incineration  to  carbonates;  so  again,  from 
the  presence  of  sulphates  and  phosphates  in  the  ash,  it  cannot  be  determined 
whether  the  sulphuric  and  phosphoric  acids  pre-existed  as  such  in  the  organic 
substance,  or  whether  they  were  present  as  sulphur  and  phosphorus,  which,  hav- 
ing become  oxidized  during  the  incineration,  have  combined  with  alkaline  or 
earthy  bases  previously  combined  with  lactic  or  carbonic  acid.  Further,  the 
carbon  of  the  organic  compound  may  produce  important  alterations,  during  its 
combustion,  in  the  condition  of  the  mineral  salts  \  thus  it  will  tend  to  reduce 
the  sulphates  to  the  condition  of  metallic  sulphurets,  and  to  volatilize  a  portion 
of  the  sulphur  in  the  condition  of  sulphurous  acid ;  and  it  will  have  a  similar 
effect  upon  the  phosphoric  acid  of  the  acid  salts.  So,  again,  common  phosphate 
of  soda,  at  a  high  temperature,  removes  a  part  of  the  base,  not  only  from  the 
carbonates  but  also  from  the  sulphates  of  the  alkalies,  as  well  as  from  the  me- 
tallic chlorides  of  the  ash;  so  that  not  only  does  all  the  alkaline  carbonate  dis- 
appear from  the  ash,  but  a  portion  of  the  hydrochloric  or  sulphuric  acid  may 
also  be  lost.  When  we  consider  these  and  other  facts  in  reference  to  the  analy- 
sis of  the  ash,  we  shall  readily  accord  with  Prof.  Lehmann's  remark,  "  that 
most  of  these  analyses  should  be  used  with  great  caution,  and  that  physiological 
conclusions  should  not  be  too  readily  drawn  from  them."  The  new  methods 
recently  introduced  by  Prof.  H.  Hose  have  led  that  eminent  analyst  to  the  con- 
clusion, that  various  compounds  of  potassium,  sodium,  calcium,  iron,  phospho- 
rus, and  sulphur  exist  preformed  in  organic  substances  in  an  unoxidized  state, 
and  take  an  important  part  in  their  metamorphoses ;  for  he  finds  that  in  the 
carbonaceous  residue  left  after  the  incineration  of  an  animal  or  vegetable  sub- 
stance, there  is  always  a  certain  quantity  of  alkaline  and  earthy  salts  which  can- 
not be  removed  from  it  by  the  ordinary  menstrua,  and  which  must,  therefore, 
exist  in  it  in  some  peculiar  state  of  combination.  And  it  is  a  confirmation  of 
this  view,  that  the  proportion  of  such  mineral  matters  contained  in  blood,  flesh, 
milk,  and  yolk-of-egg,  amounts  to  as  much  as  from  one-third  to  one-half  of  the 
whole ;  whilst  those  of  urine,  in  which  there  is  independent  reason  to  believe 
that  nearly  all  the  bases  and  radicals  are  oxidized,  do  not  amount  to  0.6  per 
cent. 

73.  In  the  following  account  of  the  mineral  components  of  the  body,  there- 
fore, those  only  will  be  mentioned,  whose  presence  in  it  has  been  clearly  deter- 
mined ;  and  even  these  must  be  arranged  in  two  categories,  according  as  their 
presence  is  essential  or  accidental.  For  whilst  there  are  certain  substances, 
which  are  constantly  met  with  in  such  large  amount,  and  which  so  obviously 
fulfil  important  purposes  in  the  economy,  that  they  may  be  unhesitatingly 
ranked  among  the  essential  components  of  the  body,  there  are  others,  which, 
although  very  commonly  present,  are  found  in  very  small  proportion,  and  under 
circumstances  which  lead  to  the  belief  that  they  neither  take  a  share  in  the 
nutritive  operations,  nor  discharge  any  mechanical  function  in  the  living  body, 
but  that  they  have  been  (so  to  speak)  accidentally  introduced  from  the  food, 
and  that  they  are  retained  merely  through  defect  of  the  eliminating  processes. 
The  presence  of  such  matters,  therefore,  is  of  comparatively  little  interest  to 
the  Physiologist ;  but  it  is  of  great  importance  to  the  Medical  Jurist,  who  may 
be  called  upon  to  declare  whether  copper,  lead,  or  arsenic,  found  in  a  dead 
body,  can  be  justly  regarded  as  a  normal  component  of  the  tissues. — We  shall 
first  consider,  then,  those  inorganic  substances  which  are  to  be  regarded  as  essen- 
tial components  of  the  Human  fabric ;  and  since  no  classification  of  them,  in 
the  present  state  of  our  knowledge,  would  be  likely  to  have  any  permanent 
scientific  value,  we  shall  arrange  them  in  the  order  of  what  appears  to  be  their 
relative  importance  in  the  economy.  From  these  we  shall  pass  to  the  sub- 


100  CHEMICAL  COMPONENTS   OP  THE   HUMAN   BODY. 

stances  found  in  the  excretions,  one  of  whose  constituents  has  been  generated  by 
the  metamorphosis  of  alimentary  matters.  And  lastly,  we  shall  notice  those 
substances  which  appear  to  be  only  accidentally  present  in  the  body. 

74.  First,  in  order  of  importance — whether  we  look  at  the  large  proportion 
of  the  bulk  of  the  fabric  which  is  formed  by  it,  to  the  influence  which  its  pre- 
sence exerts  on  the  physical  properties  of  the  various  tissues  into  which  it  enters, 
or  to  the  number  and  variety  of  purposes  to  which  it  is  subservient  in  the  chemico- 
vital  operations  of  the  living  body — is  unquestionably  Water.     The  quantity 
of  this  liquid  which  may  be  evaporated  from  the  body  by  complete  desiccation, 
is,  according  to  the  recent  experiments  of  Chevreul,1  about  two-thirds  of  its 
entire  weight ;  and  its  predominance  is  by  no  means  restricted  to  what  are  com- 
monly accounted  the  "  fluids"  of  the  system,  such  as  the  Blood,  Chyle,  Lymph, 
&c. ;  since,  as  the  following  Table  will  show,8  it  is  contained  in  nearly  as  large 
an  amount  in  several  of  the  so-called  "  solid"  tissues. 

Specific  Gravity. 

1200  to  1600 

1300 

1200 

1100 

1100 

1080  to  1090 

1070.. 

1055  to  1060 

1050  to  1055 
1040  to  1050 
1030  to  1045 
942 

When  we  examine  into  the  uses  of  this  large  proportion  of  Water,  we  find,  in 
the  first  place,  that  it  serves  a  purpose  simply  mechanical ;  imparting  to  the 
tissues  that  suppleness  and  extensibility  which  characterize  them  in  their  natural 
state,  but  which  are  completely  removed  by  drying  them.  Thus  a  piece  of  tendon, 
when  desiccated,  shrinks  into  a  firm  and  nearly  inflexible  rod,  much  resembling 
a  piece  of  dried  glue ;  yet,  if  macerated  in  water  for  a  sufficient  length  of  time,  it 
recovers,  by  the  absorption  of  liquid,  its  original  pliancy.  In  like  manner,  a 
piece  of  the  yellow  fibrous  tissue  of  the  ligamentum  nuchae  of  a  Sheep  or  Ox  dries 
into  a  hard  unyielding  substance ;  yet  if  allowed  to  imbibe  its  original  proportion 
of  water  it  recovers  its  peculiar  elasticity.  The  tissues  in  which  we  find  least 
water  are  those  whose  functions  are  most  purely  p Tiy sical;  thus  we  see  that 
Bone,  whose  sole  office  is  to  afford  an  inflexible  support,  contains  no  more  than 
from  10  to  20  per  cent,  of  fluid,  the  principal  part  even  of  this  belonging  to  the 
softer  tissues  immediately  connected  with  its  nutrition ;  so  in  the  Cuticle  and  its 
appendages,  whose  purpose  is  merely  protective,  and  which  are  partly  desiccated 
by  exposure  to  the  air,  the  proportion  of  solid  matter  is  at  least  half.  On  the  other 
hand  the  proportion  of  water  in  Muscle  averages  75  per  cent.,  and  in  the  sub- 
stance of  the  Brain  it  is  no  less  than  from  80  to  84  per  cent. ;  the  last-named 
tissues  being  among  those  of  which  the  vital  endowments  are  the  most  remark- 
able, and  being  those  (as  will  be  seen  hereafter)  in  which  the  most  rapid  nutri- 
tive changes  take  place  during  their  state  of  vital  activity. 

75.  But  further,  the  presence  of  Water  is  essential  to  the  performance  of  all 
those  chemico-vital  processes  by  which  the  integrity  of  the  living  body  is  main- 
tained; and  a  deficiency  in  the  aqueous  portion  of  the  fluids  soon  manifests  itself 

1  "  Anatomie  General,"  par  P.  A.  Beclard,  3ieme  edit.  1851,  p.  53. 

2  See  Prof.  Allen  Thomson's  "  Outlines  of  Physiology,"  p.  130. 


Bone    .        »        . 

Percentage  of  Solid  Matter. 
V       ,  .•'"„    ,     80  to  90 

Hair    . 

y_   "\.  •'"'.  ."''     60 

Cuticle         .        . 

Nerve  .       ;:.  '•'  ••  '. 

V      'V  '  '  ."       50 

•  V-  •   ;'•*••  •'•'.  f-   43 

Skin     . 
Fibrous  Textures  . 
Artery  .        .        .. 
Cartilage  ") 
Muscle       [•        .  ; 
Glands      J 
Blood  . 
Wall  of  Intestine  . 
Brain       ,;  .,..  .  >  fi< 
Fat 

30  to  40 
.     .  „        30  to  35 
.        f    -     25  to  30 

':;y;-.r;^ir,:J.iv    23  to  28 

20  to  23 

.'      ,        18 
v      .       *        16  to  20 

INORGANIC   SUBSTANCES.  101 

in  a  disturbance  of  these  operations,  even  though  the  constitution  of  the  solid 
tissues  may  have  not  yet  been  affected.  As  a  general  rule  it  may  be  stated, 
that  no  Chemical  action  takes  place  between  solid  substances,  and  that  they  re- 
quire to  be  dissolved  in  water  or  some  other  menstruum,  before  they  can  be  made 
to  affect  each  other;  and  we  find  that  this  rule  holds  good  constantly  in  the  or- 
ganized fabric,  alike  of  Plants  and  of  Animals.  No  alimentary  material  can  be 
appropriated  by  the  organism,  save  in  the  liquid  form;  and  hence  it  is  that 
Animals,  whose  food  is  solid,  are  endowed  with  a  digestive  apparatus  for  its 
reduction  to  the  state  in  which  it  may  be  absorbed  by  the  sanguiferous  and  lac- 
teal vessels,  which  answer  to  the  rootlets  of  Plants,  this  state  being  either  one 
of  complete  solution,  or  of  very  minute  division.  No  other  liquid  than  Water 
can  thus  act  as  a  solvent  for  the  various  articles  of  food  introduced  into  the 
stomach.  Again,  it  is  Water  which  continues  to  form  the  solvent  of  the  nutri- 
tive materials,  after  they  have  found  their  way  into  the  current  of  the  circulation, 
and  have  undergone  that  assimilating  process  which  prepares  them  for  being 
applied  to  the  renovation  of  the  solid  tissues;  and,  of  the  "  vital  fluid"  which 
courses  in  minute  streams  through  nearly  every  part  of  the  body,  vivifying  and 
renovating  the  tissues  which  it  traverses,  water  constitutes  as  much  as  from  76 
to  80  per  cent.  So,  again,  it  is  the  Water  of  the  blood,  which  not  merely  brings 
to  the  living  tissues  the  materials  of  their  development  in  a  state  ready  for  ap- 
propriation, but  also  takes  up  the  products  of  their  disintegration  and  decay,  and 
conveys  them,  by  a  most  complicated  and  wonderful  system  of  sewerage,  alto- 
gether out  of  the  system. — It  is  not  difficult  to  understand,  then,  how  seriously 
the  chemico- vital  operations  of  the  body  must  be  affected  by 'a  deficiency  in  the 
normal  proportion  of  this  liquid,  more  especially  as  some  of  the  substances  to  be 
transported  are  of  very  difficult  solubility ;  and  we  find  that  the  demand  for  it, 
when  it  is  withheld,  soon  becomes  even  more  pressing  than  the  demand  for  solid 
food.  It  is  remarkable  that  there  are  many  Plants  and  even  Animals,  which 
can  be  reduced  to  a  state  of  complete  inactivity  by  the  desiccation  of  their  tissues, 
without  the  absolute  loss  of  their  vitality ;  the  usual  condition  of  their  bodies 
being  recovered,  and  their  vital  powers  being  restored,  when  they  have  been 
allowed  to  imbibe  an  adequate  supply  of  water.1 

76.  Of  the  solid  inorganic  components  of  the  Human  body,  that  which  is 
of  greatest  importance  in  regard  to  its  amount  and  to  the  mechanical  purposes 
to  which  it  is  subservient,  is  Phosphate  of  Lime,  or  "  bone-earth;"  and  there  is 
a  strong  probability  that  it  is  subservient  also  to  very  important  purposes  in 
the  chemico-vital  operations  of  the  economy.3  It  is  in  the  Bones  that  this  earthy 

1  See  the  Author's  "  Principles  of  Physiology,  General  and  Comparative,"  p.  39,  Am.  Ed. 

2  "The  constant  occurrence  of  Phosphate  of  Lime  in  the  histogenetic  substances,  and 
especially  in  the  plastic  fluids,"  remarks  Prof.  Lehmann,  "as  well  as  its  deposition  in  many 
pathologically-degenerated  cells  of  the  animal  body,  obviously  strengthens  the  opinion  that 
this  substance  plays  an  important  part  in  the  metamorphosis  of  the  animal  tissues,  and 
especially  in  the  formation  and  in  the  subsequent  changes  of  animal  cells."     (Op.  cit. 
p.  416.)     This  doctrine  has  been  strongly  advocated  in  a  work  entitled  "Der  Phosphora- 
saure  Kalk  in  physiologischer  und  therapeutischer  Beziehung,"  (Gottingen,  I860,)  by  Dr. 
Beneke ;  who  has  further  maintained  that,  in  various  diseases  which  are  characterized  by 
imperfect  nutrition,  the  real  source  of  the  want  of  formative  action  lies  in  the  deficiency  of 
this  substance,  which  is  carried  out  of  the  system  in  abnormal  quantity,  whenever  an  excess 
of  Oxalic  acid  is  generated  within  it ;  in  proof  of  which  he  alleges  that  great  benefit  is  de- 
rived in  such  cases  from  the  remedial  administration  of  phosphate  of  lime,  as  well  as  from 
the  prevention  of  the  formation' of  oxalic  acid,  where  this  is  possible.     (See  the  "Proceed- 
ings of  the  Royal  Society,"  June  20, 1850.) — It  is  remarkable  that  the  glandular  epithelium 
of  the  mantle  of  certain  Bivalve  Mollusks,  which  seems  to  be  specially  concerned  in  the 
formation  of  the  shell,  should  be  found  to  contain  as  much  as  15  per  cent,  of  phosphate  of 
lime,  with  only  3  per  cent,  of  the  carbonate,  the  remainder  of  their  solid  components  being 
made  up  of  organic  matter ;  yet  the  shell  itself  contains  no  more  than  a  trace  of  the  phosphate. 
(See  C.  Schmidt,  "  Zur  vergleichenden  Physiologic,"  pp.  58-60.) 


102  CHEMICAL   COMPONENTS   OP   THE   HUMAN  BODY. 

f . 

salt  (which  has  been  recently  determined  to  be  composed  of  3  equivs.  Lime  + 1 
equiv.  Phosphoric  acid,  and  not,  as  Berzelius  supposed,  8  equivs.  Lime  -f  3  equivs. 
Phosphoric  acid)  presents  itself  in  the  greatest  abundance.  In  healthy  bones, 
its  proportion  ranges  from  48  to  59  per  cent. ;  being  greatest,  as  Yon  Bibra  has 
shown,  in  those  bones  which  are  most  required  to  possess  resisting  power.1  In 
the  Dentine  of  teeth,  its  proportion  rises  to  66  per  cent. ;  and  in  the  Enamel  to 
nearly  90  per  cent.  It  is  remarkable  that,  in  this  last  situation,  it  should  pre1- 
sent  an  almost  crystalline  mode  of  aggregation,  whilst  the  Enamel  is  the  hardest 
of  all  organic  substances,  being  capable  of  striking  fire  with  steel ;  and  it  seems 
scarcely  possible  to  avoid  tracing  a  connection  between  these  two  facts,  more 
especially  as  phosphate  of  lime,  in  certain  states  of  crystallization,  forms  one  of 
the  hardest  of  all  mineral  bodies.  On  the  other  hand,  in  bones  which  are  un- 
dergoing softening  from  any  form  of  disease,  the  proportion  of  phosphate  of  lime 
is  diminished ;  and  an  artificial  softening  may  be  induced  by  restricting  animals 
to  food  containing  little  or  none  of  this  salt.  In  regard  to  the  mode  in  which 
it  is  deposited  there  is  a  strong  probability  (as  already  remarked,  §  33)  that  the 
earthy  salt  forms  a  definite  chemical  compound  with  the  organic  base.  It  is  not 
only  in  the  skeleton,  however,  that  phosphate  of  lime  presents  itself;  for  it  is  a 
constituent  of  all  the  soft  tissues  of  the  body,  being  intimately  united  with  the 
organic  compounds  which  are  their  essential  constituents.  Thus  the  ash  of 
Cartilage,  amounting  to  more  than  4  per  cent.,  chiefly  consists  of  bone-earth; 
and  well-dried  Muscular  fibre  contains  about  1  per  cent,  of  this  substance.  It 
would  almost  seem,  indeed,  to  be  a  necessary  accompaniment  to  the  protein- 
compounds,  which  are  with  difficulty  freed  from  it  completely  (§§  20,  22).  As 
might  be  expected,  therefore,  it  is  met  with  in  solution  in  all  the  animal  fluids ; 
both  those  which  contain  the  nutritive  materials,  and  those  which  are  conveying 
out  of  the  body  the  waste  matters  of  the  system.  In  the  former,  it  is  no  doubt 
held  in  solution  by  the  protein-compounds ;  thus  in  Milk,  we  find  it  in  intimate 
union  with  the  casein,  which  has  a  special  solvent  power  for  bone-earth ;  and  in 
Blood  it  is  in  like  manner  united  with  the  albumen,  and,  in  a  less  degree,  with 
the  fibrin.  All  fluids  into  which  these  substances  pass,  even  in  a  state  of  in- 
cipient metamorphosis — as  the  lymph  of  the  lymphatics,  the  serous  fluid  which 
permeates  the  lacunae  of  the  tissues,  the  salivary,  gastric,  and  pancreatic  secre- 
tions, &c. — contain  phosphate  of  lime  as  their  accompaniment.  On  the  other 
hand,  it  forms  a  considerable  proportion  of  the  inorganic  constituents  of  the 
urine ;  and  there  its  condition  is  entirely  different,  as  it  is  completely  dissociated 
from  organic  matter.  Its  solubility  in  that  fluid  seems  due  to  the  fact  that, 
although  entirely  insoluble  in  water,  a  small  quantity  of  this  salt  is  taken  up  by 
solutions  of  chloride  of  sodium  or  of  hydrochlorate  of  ammonia,  or  by  fluids 
charged  with  carbonic  acid.  And  it  is  further  remarkable,  that  lactic  acid  has 
a  special  solvent  power  for  phosphate  of  lime;  as  much  as  68 £  parts  of  this  salt 
being  dissolved  by  100  parts  of  the  anhydrous  acid. — It  is  probable,  as  pointed 
out  by  Lehmann,  that  phosphate  of  lime  may  be  formed  within  the  body,  by  the 
union  of  phosphoric  acid  set  free  from  the  alkaline  phosphates,  or  generated  by 
the  oxidation  of  phosphorus,  with  carbonate  of  lime  contained  in  the  food  or 
water  consumed;  but  there  cannot  be  a  doubt  that  the  greater  part  of  what  is 
contained  in  the  body,  is  introduced  there  ready  formed.  Of  its  abundance  in 
the  aliment  of  carnivorpus  animals,  there  is  no  need  to  say  more ;  and  it  is 
present  to  a  large  extent  in  all  the  most  nutritious  articles  of  vegetable  food, 
especially  in  the  corn-grains. 

77.  Although  the  phosphate  of  lime  is  the  principal  solidifying  ingredient 
of  the  Bones  and  Teeth  of  the  higher  animals,  yet  they  also  contain  a  considera- 

1  See  his  "Chemische  Untersuchungen  xiber  die  Knocken  und  Ziihne  des  Menschen, 
und  der  Wirbelthiere,"  Schweinfurt,  1844. 


INORGANIC  SUBSTANCES.  103 

ble  amount  of  the  Carbonate;  the  proportion  which  the  latter  salt  bears  to  the 
former  being  greater  in  young  animals  than  in  old.1  Thus,  according  to  Leh- 
mann,  the  ratio  of  the  carbonate  to  the  phosphate  is  as  1  :  3.8  in  the  Bones  of 
a  new-born  child,  as  1  :  5.9  in  those  of  an  adult  male,  and  as  1  :  8.1  in  those  of 
an  old  male.  So,  according  to  Lassaigne,  the  proportion  in  the  Teeth  of  a  new- 
born child  is  as  1  :  3.6,  in  those  of  a  child  six  years  old  as  1  :  5.3,  in  those  of 
an  adult  as  1:6,  and  in  those  of  an  aged  man  as  1  :  6.6.  In  the  enamel  of 
human  teeth,  according  to  Yon  Bibra  (pp.  cit.),  the  proportion  is  as  1  :  20.5. — 
It  is  worthy  of  note  that  the  massive  skeletons  of  the  inert  Polypifera  and  Mol- 
lusca  are  consolidated  by  carbonate  of  lime,  almost  to  the  complete  exclusion  of 
the  Phosphate ;  whilst  the  comparatively  light  and  thin  calcareous  casing  of  the 
Crustacea,  which,  like  the  osseous  skeleton  of  Vertebrata,  serves  for  the  attach- 
ment of  the  muscles  that  move  the  body,  and  therefore  needs  considerable 
strength  in  proportion  to  its  substance,  contains  an  appreciable  amount  of  the 
phosphate.  In  phleboliths  and  other  abnormal  calcareous  concretions,  creta- 
ceous tubercles,  &c.,  the  proportion  of  carbonate  of  lime  is  usually  high.  It  is 
curious  that  carbonate  of  lime  should  normally  present  itself  in  a  crystalline 
form,  in  a  certain  part  of  the  human  organism,  namely,  within  the  membranous 
lining  of  the  vestibule  of  the  ear,  on  the  inner  surface  of  which  it  is  deposited, 
the  crystals  being  sometimes  contained  within  cells.  They  are  very  minute,  so 
as  even  to  exhibit  the  molecular  movements  characteristic  of  particles  of  very 
small  dimensions ;  yet  their  crystalline  form  may  be  determined  to  be  that  of  a 
prism  derivable  from  the  rhombohedron  of  calc-spar.  Crystals  of  this  nature 
occur  much  more  frequently  and  abundantly  among  the  lower  animals,  both  in 
the  organs  of  hearing  and  in  other  parts ;  thus  among  the  Batrachia  they  are 
found  in  the  membrane  of  the  brain,  and  in  that  which  lines  the  intervertebral  fora- 
mina.— For  the  sources  of  carbonate  of  lime  in  the  animal  organism,  it  is  not 
requisite  to  go  far  to  seek ;  since,  almost  all  the  water  which  is  used  as  drink 
contains  an  appreciable  portion  of  it,  and  in  the  waters  that  have  percolated 
through  calcareous  soils,  the  amount  of  this  salt  is  very  considerable.  More- 
over, lime  is  taken  in  by  all  herbivorous  animals,  in  combination  with  vegeta- 
ble acids ;  and  these  salts  are  converted  into  carbonates  within  the  body ;  so 
that  the  carbonate  of  lime,  if  not  converted  into  a  sulphate,  muriate,  or  phos- 
phate, is  excreted  as  such  by  the  urine,  in  which  it  consequently  appears  occa- 
sionally in  large  quantities.  This  substance  is  probably  held  in  solution  in  the 
animal  fluids  (as  in  ordinary  spring  water)  by  free  carbonic  acid ;  but  the  chlo- 
ride of  sodium,  and  other  alkaline  salts  which  they  contain,  may  exert  an  addi- 
tional solvent  power. — Of  this  substance  it  may  be  remarked,  in  conclusion,  that 
there  is  no  evidence  of  its  subserviency  to  any  other  than  a  mechanical  purpose 
within  the  living  body. 

78.  With  the  foregoing  calcareous  salts,  a  small  quantity  of  Phosphate  of 
Magnesia  is  almost  invariably  associated.  It  is  chiefly  found  in  the  bones ;  and 
its  proportion  is  somewhat  larger  in  the  bones  of  herbivora  than  in  those  of  car- 
nivora,  the  largest  proportion  presenting  itself  in  the  teeth  of  Pachydermata. 
The  ash  of  all  the  animal  fluids  and  tissues  contains  a  little  phosphate  of  mag- 
nesia ;  and  its  presence  is  made  known  by  the  microscope  in  tissues  in  which 
putrefaction  has  actively  commenced,  these  being  everywhere  studded  with 
crystals  of  the  "  triple  phosphate"  of  ammonia  and  magnesia,  a  salt  which  is 
formed  wherever  phosphate  of  magnesia  is  dissolved  in  an  ammoniacal  liquid. 
Phosphate  of  magnesia  is  introduced  into  the  body  as  a  part  of  the  ordinary 
food  both  of  carnivorous  and  herbivorous  animals ;  but  it  exists  in  much  larger 
proportion  in  many  vegetable  substances,  especially  the  seeds  of  the  Cerealia, 

1  This  statement  is  controverted  by  Von  Bibra  ;  but  it  is  supported  by  the  analyses  of 
Lehmann  and  many  other  chemists. 


104  CHEMICAL   COMPONENTS   OP   THE   HUMAN   BODY. 

than  it  does  in  animal  flesh ;  and  as  no  more  seems  to  be  taken  up  than  the  sys- 
tem requires,  the  residue  is  carried  off  in  the  feces,  of  whose  ash  from  10  £  to 
13  per  cent,  has  been  found  to  consist  of  phosphate  of  magnesia  when  a  mixed 
diet  was  employed.  It  seems  to  be  from  the  superfluity  of  this  salt  in  their 
food,  that  the  tendency  to  intestinal  concretions  arises  in  many  herbivorous  ani- 
mals ;  those  which  are  common  in  the  horse,  for  example,  consisting  almost 
entirely  of  the  triple  phosphate,  with  fragments  of  straw,  &c.  The  proportion 
of  this  salt  which  is  absorbed,  and  which  is  embodied  in  the  various  tissues, 
seems  normally  to  enter  the  urine  when  set  free  by  their  disintegration,  and  to 
be  thus  carried  out  of  the  body,  at  a  rate  corresponding  to  that  of  its  introduc- 
tion. If,  however,  free  ammonia  should  be  generated,  either  by  decomposition 
of  the  urine,  or  by  a  state  of  incipient  putrescence  of  the  solids  or  fluids  of  the 
body,  the  triple  phosphate  is  produced ;  and  thus  it  is  that  it  is  often  found  in 
considerable  amount  in  the  urine,  and  that  it  presents  itself  in  the  fecal  evacua- 
tions in  cases  of  typhoid  fever.  That  it  is  a  real  excretion  in  the  latter  case,  is 
sufficiently  obvious  from  the  fact  that  it  cannot  have  been  furnished  by  the 
food ;  and  it  is  interesting  to  observe  that  its  crystals  are  found  thickly  studding 
the  ulcerated  patches  of  intestinal  glandulse,  which  are  probably  the  seat  of  their 
elimination. — There  is  no  reason  to  think  that  the  function  of  phosphate  of  mag- 
nesia in  the  system  is  less  mechanical  than  that  of  carbonate  of  lime. 

79.  A  minute  proportion  of  Fluoride  of  Calcium  has  been  so  constantly 
found  in  the  bones,  that  it  may  be  considered  as  one  of  their  ordinary  compo- 
nents ;  how  far,  however,  its  presence  is  to  be  regarded  as  essential,  or  how  far 
it  depends  upon  the  combination  of  this  with  other  calcareous  salts  contained  in 
the  food,  has  not  yet  been  determined.  That  it  is  specially  attracted  by  osseous 
tissue,  even  when  this  is  no  longer  alive,  appears  from  the  fact  that  fossil  bones 
are  often  found  to  contain  it  in  extraordinary  amount,  no  less  than  15  or  16  per 
cent,  being  occasionally  discovered  in  them ;  and  this  can  scarcely  have  been 
derived  from  any  other  source  than  a  percolation  of  water  charged  with  fluoride 
of  calcium  through  the  strata  in  which  the  bones  were  imbedded.  It  would 
seem,  moreover,  that  the  teeth,  and  especially  the  enamel,  contain  a  much  larger 
proportion  of  this  substance  than  does  any  other  living  texture ;  thus  Berzelius 
found  2.1  per  cent,  of  fluoride  of  calcium  in  the  dentine,  and  3.2  per  cent,  in 
the  enamel,  of  a  human  tooth.  It  is  obvious  that  this  compound  must  be  de- 
rived from  the  solid  or  liquid  aliment  introduced  into  the  system,  and  must  be 
absorbed  into  the  blood ;  and  there  is  experimental  proof  that  such  is  the  case. 
Fluoride  of  calcium  may  be  detected  in  many  mineral  waters,  and  is  soluble, 
according  to  the  experiments  of  Dr.  G.  Wilson,1  in  about  28,000  times  its  weight 
of  water;  and  it  is  contained  in  the  ashes  of  plants  growing  on  micaceous  soils. 
The  same  experimenter  appears  clearly  to  have  determined  its  presence  in  Blood 
and  in  Milk,  although  he  has  not  made  a  quantitative  appreciation  of  it ;  and 
we  may  fairly  expect  that  it  might  be  detected  in  the  Urine,  if  a  sufficiently 
large  amount  were  examined,  this  being  the  channel  by  which  it  would  proba- 
bly find  its  way  out  of  the  body.2 

1  Reports  of  British  Association  for  1850,  pp.  67,  68. 

2  It  is  right  here  to  mention  that,  although  the  presence  of  fluoride  of  calcium  in  the 
animal  body  has  been  very  generally  admitted,  a  doubt  has  been  thrown  upon  the  validity 
of  the  proofs  usually  relied  on.     Dr.  G.  0.  Rees  states  ("Guy's  Hospital  Reports,"  No. 
ix.)  that  he  could  not  succeed  in  unequivocally  detecting  this  salt  in  bone-ash,  although  as 
little  as  0.3  gr.  added  to  100  grains  of  bone-ash  produced  unequivocal  corrosion  of  glass ;  and 
he  is  disposed  to  attribute  the  very  different  results  obtained  by  other  Chemists,  to  the 
power  of  phosphoric  acid  to  corrode  glass  of  inferior  quality. — It  may  be,  however,  that 
the  presence  of  this  salt  is   purely  accidental,  depending  upon  an  impregnation  of  the 
waters  of  the  neighborhood,  and  upon  its  reception  into  plants  growing  under  circum- 
stances in  which  it  is  abundantly  supplied.     If  this  be  the  case,  it  might  be  met  with  in 
considerable  amount  in  some  bones,  and  be  entirely  wanting  in  others. 


INORGANIC   SUBSTANCES.  105 

80.  Although  Silica  is  one  of  the  most  important  mineral  ingredients  of 
many  Plants,  and  is  also  abundant  in  some  of  the  lower  forms  of  Animal  struc- 
ture, yet  it  is  present  to  only  a  very  small  extent  in  the  Human  organism,  the 
sole  tissue  of  which  it  seems  to  be  a  normal  constituent  being  the  Hair.1     Ac- 
cording to  the  analysis  of  Laer  and  Grorup-Besanez,  about  0.22  per  cent,  of  silica 
is  to  be  found  in  the  ordinary  brown  hair  of  man ;  the  ashes  of  which  contain 
nearly  13.9  of  this  earth.     It  has  been  discovered  in  the  blood  of  Man  by  Mil- 
Ion,  and  in  that  of  the  Ox  by  Weber,  in  both  cases,  however,  in  a  quantity  not 
exceeding  0.20  per  cent,  of  the  ash ;  in  the  ash  of  birds'  blood,  on  the  other 
hand,  its  proportion  is  about  five  times  as  great  as  might  be  expected  from  the 
larger  demand  for  it  in  their  organisms.     Silica  has  been  detected  also  in  the 
bile  and  urine,  and  is  obviously  carried  out  of  the  system  through  these  chan- 
nels ;  what  is  found  in  the  solid  excrements  has  obviously  been  derived  directly 
from  the  food.     It  is  in  the  seed-coats  of  many  seeds,  especially  those  of 
the  Monocotyledonous  division,  that  the  chief  source  of  the  silica  introduced 
into  the  bodies  of  animals  is  to  be  found ;  and  hence  it  is  that  the  feathers  of 
granivorous  birds  present  a  much  larger  proportion  of  silica  than  any  others, 
and  that  granivorous  quadrupeds  are  peculiarly  subject  to  intestinal  concretions 
including  a  large  quantity  of  silica. 

81.  Among  those  inorganic  components  of  the  Human  body,  whose  function 
is  rather  chemical  than  mechanical,  we  may  first  notice  Hydrochloric  acid,  which 
may  be  regarded  as  an  occasional,  if  not  a  constant  component  of  the  gastric 
fluid.3     Both  lactic  and  hydrochloric  acids  have  a  powerful  action  on  albuminous 
substances ;  and  there  is  reason  to  think  that  the  acid  reaction  and  solvent 
powers  of  the  gastric  fluid  may  be  due  to  either  one  or  the  other.     In  the  gas- 
tric fluid  of  Man,  however,  it  seems  certain  (as  will  be  shown,  hereafter,  CHAP. 
Vii.)  that  free  hydrochloric  acid  normally  exists,  in  such  a  proportion  as  to 
render  it  efficient  as  the  solvent. 

82.  Of  all  the  mineral  constituents  of  the  Human  organism,  there  is  none 
more  important  in  a  chemical  point  of  view  than   Chloride  of  Sodium.     This 
substance  occurs  in  nearly  every  part  of  the  body,  both  solid  and  fluid,  in  close 
and  intimate  relation  with  the  organic  compounds,  whose  chemical  and  physical 
properties  are  materially  influenced  by  it :  thus  Albumen  partly  owes  its  solu- 
bility to  this  salt,  and  the  differences  which  it  presents  in  coagulating  are  in  great 
degree  dependent  upon  the  quantity  of  it  that  is  present;  pure  Casein,  which  is 
otherwise  insoluble,  is  also  dissolved  by  common  salt;  and  if  salt  be  added  in 
increased  proportion,  it  has  the  power  of  impeding  the  coagulation  of  the  Fibrin 
of  the  blood.     Moreover,  this  substance  js  not  only  uniformly  present,  but  exists 
in  nearly  definite  and  constant  proportions,  in  the  several  tissues  and  fluids; 
and  the  existence  of  a  provision  for  the  limitation  of  the  quantity  retained  in 
the  system  renders  these  proportions  but  little  liable  to  be  affected,  in  the  way 
of  excess  at  least,  by  the  quantity  of  salt  which  the  food  may  contain.     Thus 
Lehmann  found  that  whilst  his  own  blood  in  a  normal  state  contained  4.14  parts 
of  chloride  of  sodium  in  1000,  this  proportion  was  only  increased  to  4.15  after 

1  It  is  interesting  to  remark  that  Gorup-Besanez  has  found  Silica  to  be  a  uniform  com- 
ponent of  the  feathers  of  Birds ;  of  the  ashes  of  which  it  constitutes  from  6.9  to  as  much 
as  65  per  cent.     Moreover,  the  silica  presents  itself  in  much  larger  amount  in  the  feathers 
of  adult  birds  than  in  those  of  the  young,  only  traces  of  it  being  found  in  newly-grown 
feathers ;  and  further,  it  is  in  the  feathers  of  the  wings,  in  which  the  greatest  rigidity  is 
required,  that  the  largest  amount  of  silica  is  contained. 

2  This  acid  can  always  be  obtained  from  gastric  fluid  by  distillation.    It  has  been  found, 
however,  that  lactic  acid,  which  is  also  present  in  the  stomach  ($  49),  has  the  power  of 
decomposing  chloride  of  sodium,  and  of  setting  free  hydrochloric  acid,  by  the  aid  of  heat ; 
but  whether  it  ordinarily  does  this  at  the  temperature  of  the  stomach,  is  doubtful.     Even 
during  evaporation  in  vacuo,  lactic  acid  will  decompose  chloride  of  calcium,  and  will  thus 
disengage  hydrochloric  acid. 


106 


CHEMICAL  COMPONENTS  OP  THE  HUMAN  BODY. 


the  use  of  very  salt  food  which  caused  intense  thirst,  and  only  rose  to  4.18  when 
two  ounces  of  salt  had  been  taken  an  hour  before,  and  two  quarts  of  water  had 
been  drunk  in  the  interval.  The  quantity  of  salt  in  the  blood  in  different  dis- 
eases, however,  is  liable  to  great  variation ;  and  there  can  be  little  doubt  that 
this  variation  is  intimately  connected  (though  whether  in  the  relation  of  cause 
or  in  that  of  effect,  we  are  scarcely  yet  entitled  to  surmise)  with  the  histological 
and  other  transformations  of  the  components  of  the  blood.1  The  proportion  of 
chloride  of  sodium  differs  greatly  in  the  several  tissues,  and  also  at  different 
periods  of  the  development  of  the  same  tissue.  Thus  in  Muscle,  according  to  En- 
derlin,  100  parts  of  the  ash  left  after  incineration  of  ox-flesh  yielded  nearly  46 
per  cent,  of  the  chlorides  of  sodium  and  potassium  ;  which,  as  this  ash  constitutes 
4.23  per  cent,  of  the  dried  flesh,  would  give  1.94  as  the  proportion  of  chloride 
of  sodium  in  100  parts  of  the  latter ;  and  reckoning  this  dried  residue  to  con- 
stitute 23  per  cent,  of  the  whole  substance  of  the  muscle  (the  remaining  77 
parts  being  water),  the  proportion  of  chloride  of  sodium  in  the  latter  will  be 
0.44;  these  figures,  as  will  be  presently  seen,  bearing  a  remarkably  close  corre- 
spondence to  those  which  represent  the  proportion  of  chloride  of  sodium  in  the  ash, 
solid  residue,  and  entire  mass,  of  the  'Blood.  Next  to  muscle,  the  largest  percentage 
of  chloride  of  sodium  seems  to  be  contained  in  Cartilage;  and  this  especially  in  the 
temporary  cartilages  of  the  foetus,  the  proportion  diminishing  as  the  phosphate  of 
lime  is  deposited.  The  percentage  of  chloride  of  sodium  contained  in  the  ash  of 
the  costal  cartilage  of  an  adult  has  been  stated  at  8.2,  and  in  the  laryngeal  cartilage 
at  11.2 ;  but  as  the  ash  does  not  constitute  above  3.4  per  cent,  of  the  entire 
substance,  the  percentage  of  chloride  of  sodium  in  the  latter  is  at  most  0.38 
of  the  whole,  or  less  than  that  of  blood  and  muscle.  In  Bone,  only  from  0.7  to 
1.5  per  cent,  could  be  extracted  from  the  ash. — Besides  the  important  uses  of 
common  salt  in  the  Blood  which  have  been  already  adverted  to,  it  serves  the 
important  purpose  of  furnishing  the  hydrochloric  acid  required  (by  many 
animals  at  least)  for  the  gastric  secretion  (§  81);  and  it  also  furnishes  the  soda- 
base  for  the  alkaline  phosphate,  whose  presence  in  the  blood  appears  to  serve  a 
most  important  purpose  in  the  respiratory  process  (§  84).  Moreover,  there  is 
reason  to  think,  from  the  experiments  of  Boussingault  upon  animals,  as  well  as 
from  other  considerations,  that  the  presence  of  salt  in  the  blood  and  excreted 
fluids  facilitates  the  deportation  of  excrementitious  substances ,  from  the  body. 
— The  proportion  in  which  it  occurs  in  the  principal  animal  fluids  is  repre- 
sented by  the  following  table,  constructed  by  Prof.  Lehmann  chiefly  from  his 
own  analyses : — 

PERCENTAGE  OF  CHLORIDE  OF  SODIUM  IN  VARIOUS  ANIMAL  FLUIDS,  THEIR  SOLID  RESIDUE, 

AND  THEIR  ASH. 


Human  Blood 

Blood  of  Horse 

Chyle    .        ; 

Lymph  (Nasse) 

Serum  of  the  Bl 

Blood  of  the  Cat  (Nasse) 

Chyle  (Nasse) 

Human  Milk 

Saliva   . 

Gastric  Juice  of  Dog 

Human  Bile 

Mucus  (Nasse) 

Serum  of  Pus  (Nasse)    . 


- 

Liquid. 
0.421 

. 

0.510 

•   " 

0.531 

IfiKJr  <WW 

0.412 

d  (Nasse) 

0.405 

Nasse) 

0.537 

.        . 

0.710 

i               •' 

0.087 

J 

0.153 

°g          • 

0.126 

0.364 

•  '"'''   ''«            ' 

0.583 

BBC)  '. 

1.260 

Solid  Residue. 

1.931 

2.750 

8.313 

8.246 

5.200 

2.826 

7.529 

0.726 
12.988 
12.753 

3.353 
13.100 
11.454 


Ash. 
57.641 
67.105 
67.884 
72.902 
59.090 
67.128 
62.286 
33.089 
62.195 
42.089 
30.464 
70.000 
72.330 


1  The  special  influence  of  the  saline  constituents  of  the  Blood  upon  its  red  corpuscles, 
will  be  noticed  hereafter  (§139). 


INORGANIC  SUBSTANCES.  107 

The  quantity  of  chloride  of  sodium  contained  in  the  Urine  is  liable  to  very 
great  variations,  being  greatly  augmented  when  an  excess  of  salt  has  been  in- 
gested either  in  food  or  in  water ;  and  it  is  obvious  that  it  is  one  of  the  offices 
of  the  kidney  to  filter  off,  so  to  speak,  the  superfluity  of  this  substance  from  the 
blood.  Chloride  of  sodium  finds  its  way  into  the  system,  as  a  constituent  of 
almost  all  articles  both  of  vegetable  and  animal  diet;  it  is  also  contained,  though 
in  small  proportion,  in  most  of  the  water  which  is  used  as  drink ;  and  by  most 
races  of  man,  it  is  used  in  considerable  amount  as  a  condiment.  It  seems  pro- 
bable, however,  that  the  quantity  which  is  really  required  is  usually  supplied 
by  the  ordinary  diet;  and  there  are  numerous  tribes  which  subsist  in  health 
and  vigor  without  any  additional  source  of  it.  Probably  the  inhabitants  of 
inland  countries  may  stand  in  greater  need  of  salt,  than  the  dwellers  on  the 
seaboard ;  since  the  plants  grown  in  the  latter  situation  contain  a  much  larger 
amount  of  this  saline  derived  from  the  atmosphere,  than  do  those  raised  at  a 
great  distance  from  the  ocean. 

83.  That  a  small  quantity  of  the  Alkaline  Carbonates  (especially  of  carbon- 
ate of  soda)  exists  in  ordinary  Blood,  though  its  presence  was  denied  by  Ender- 
lin,  is  now  generally  admitted  by  Chemists.  Lehmann  states  the  proportion, 
as  the  mean  of  ten  analyses  of  ox-blood,  at  0.16  per  cent.  Since  free  carbonic 
acid  is  undoubtedly  present  both  in  venous  and  arterial  blood,  it  has  been  main- 
tained that  its  soda  must  be  in  the  condition  of  a  bicarbonate,  since  the  ordinary 
carbonate  of  soda  cannot  remain  as  such  in  the  presence  of  a  free  acid ;  but  the 
soda-salt,  whatever  be  its  nature,  is  probably  united  so  intimately  with  the  pro- 
tein-compounds, that  its  ordinary  modes  of  combination  are  greatly  modified. 
The  carbonate  and  bicarbonate  of  soda  (particularly  the  latter)  have  a  special 
power  of  rendering  Albumen  soluble ;  and  their  presence  in  large  quantity  has 
the  effect  of  impeding  or  altogether  preventing  the  coagulation  of  the  Fibrin, 
apparently  through  their  power  of  chemically  dissolving  it. — The  alkaline  car- 
bonates in  the  blood  are  probably  for  the  most  part  not  introduced  as  such,  but 
result  from  the  decomposition  of  the  lactates  (§  49)  and  of  other  salts  formed 
by  organic  acids,  a  considerable  amount  of  which  must  be  ingested  in  the  food 
of  herbivorous  animals.  And  one,  at  least,  of  their  functions  within  the  system, 
is  to  supply  a  base  for  the  acids  which  are  generated  within  it;  these  acids  being 
produced  (as  in  the  case  of  phosphoric  and  sulphuric  acids)  during  the  disinte- 
gration of  the  tissues,  and  forming,  with  bases,  neutral  salts  which  are  speedily 
eliminated  from  the  system  by  the  kidneys ;  or  (as  in  the  case  of  lactic  acid) 
being  developed  by  the  metamorphosis  of  compounds  which  may  have  never 
formed  part  of  the  living  tissues,  and  being  only  united  temporarily  with  the 
base,  to  be  reduced  by  the  respiratory  process,  leaving  the  base  in  its  original 
state  of  combination  with  carbonic  acid. — The  following,  according  to  Prof. 
Liebig,  are  among  the  important  purposes  which  are  served  by  the  alkalinity  of 
the  Blood.  By  its  means,  the  chief  constituents  of  the  blood  are  kept  in  their 
fluid  state ;  the  extreme  facility  with  which  the  blood  moves  through  the 
minutest  vessels  is  due  to  the  small  degree  of  permeability  of  the  walls  of  these 
vessels  for  the  alkaline  fluid.  The  free  alkali  acts  as  a  resistance  to  many 
causes,  which,  in  the  absence  of  the  alkali,  would  coagulate  the  albumen.  The 
more  alkali  the  blood  contains,  the  higher  is  the  temperature  at  which  its  albu- 
men coagulates ;  and  with  a  certain  amount  of  alkali,  the  blood  is  no  longer 
coagulated  by  heat  at  all.  On  the  alkali  depends  a  remarkable  property  of  the 
blood,  that  of  dissolving  the  oxides  of  iron,  which  are  ingredients  of  the  color- 
ing matters  of  the  blood,  as  well  as  other  metallic  oxides,  so  as  to  form  perfectly 
transparent  solutions.  The  free  alkali  serves  also  to  promote  the  combustion 
of  organic  compounds,  which  in  its  presence  acquire  a  power  of  combining  with 
oxygen  that  they  do  not  possess  alone  at  ordinary  temperatures ;  thus  milk- 
sugar  and  grape-sugar,  in  presence  of  a  free  alkali,  and  with  the  aid  of  a  gentle 


108  CHEMICAL   COMPONENTS   OP   THE   HUMAN  BODY. 

heat,  deprive  even  metallic  oxides  of  their  oxygen.  Further,  it  is  by  the  alka- 
linity of  the  blood,  that  the  metamorphosis  of  the  malic,  citric,  tartaric,  and 
other  organic  acids  used  as  food,  is  promoted ;  and  the  same  influence  is  exerted 
even  over  uric  acid,  which,  when  introduced  into  the  system  from  without,  is 
speedily  resolved  into  urea  and  oxalic  acid.  If  on  the  other  hand,  there  be  not 
an  adequate  supply  of  alkali  in  the  blood,  some  of  the  vegetable  acids  (such  as 
the  gallic  and  tartaric)  pass  through  it  unchanged,  and  make  their  appearance 
in  the  urine ;  this  being  especially  the  case  in  carnivorous  animals,  whose  blood 
(according  to  Prof.  Liebig)  contains  more  of  the  alkaline  phosphates,  and  less  of 
the  carbonates,  than  that  of  herbivorous  or  omnivorous  animals.1  It  was  at  one 
time  maintained  by  Prof.  Liebig,  that  the  presence  of  carbonate  of  soda  in  the 
serum  of  the  blood  promotes  the  absorption  of  carbonic  acid  by  the  circulating 
fluid,  this  being  displaced  by  oxygen  in  the  lungs.  He  has  latterly  urged,  how- 
ever, that  this  action  must  be  very  insignificant,  in  comparison  with  that  which 
is  performed  by  phosphate  of  soda.3 

84.  The  ordinary  analyses  of  the  blood  and  of  other  fluids  of  the  living  body 
indicate  the  presence  of  a  considerable  amount  of  the  Alkaline  Phosphates,  soda 
being  the  predominating  base ;  and  much  ingenious  speculation  has  been  put 
forth  concerning  their  special  uses  in  promoting  the  metamorphoses  of  tissue, 
arising  out  of  the  remarkable  variety  in  the  combining  proportions  of  phosphoric 
acid  and  its  bases.  But  it  has  been  rendered  doubtful,  to  say  the  least,  by  the 
recent  analyses  of  Rose,  whether  the  phosphates  do  exist  as  such  in  the  blood, 
£c.,  and  whether  they  are  not  rather  formed  during  the  incinerating  process,  by 
the  oxidation  of  phosphorus,  and  the  combination  of  the  phosphoric  acid  thus 
formed  with  the  alkaline  bases  previously  combined  with  carbonic  or  with  or- 
ganic acids.  Moreover,  as  it  appears  from  the  researches  of  Prof.  Liebig  just 
cited,  that  the  relative  amount  of  the  alkaline  phosphates  and  carbonates  in  the 
blood  of  different  animals,  is  subject  to  great  variation  in  accordance  with  the 
nature  of  their  food  (the  former  being  in  largest  proportion  in  the  blood  of  car- 
nivorous, and  the  latter  in  that  of  purely  herbivorous  animals),  it  may  be  sus- 
pected that  substances,  whose  quantity  seems  to  be  so  much  a  matter  of  indif- 
ference, must  either  be  of  secondary  importance  in  the  vital  economy,  or  must 
be  in  some  degree  vicarious  with  each  other.  This  last  idea  is  perhaps  the 
nearest  to  the  truth ;  for,  according  to  Prof.  Liebig,  the  alkalinity  of  the  blood 
in  carnivorous  animals  is  due  much  rather  to  the  presence  of  the  basic  phosphate 
of  soda  than  to  that  of  the  carbonate.  Moreover,  the  remarkable  power  which 
the  serum  of  the  blood  possesses  for  the  absorption  of  carbonic  acid  (nearly  twice 
its  volume  of  that  gas  being  taken  up  by  it  at  the  ordinary  temperature,  which 
is  double  the  amount  which  water  will  absorb  under  the  same  circumstances), 
is  mainly  due  to  the  presence  of  phosphate  of  soda ;  a  solution  of  1  part  of 
which  in  100  parts  of  water  is  found  to  take  up  twice  as  much  carbonic  acid  as 
an  equal  bulk  of  water  will  absorb  at  the  same  temperature,  two-thirds  of  this 
being  readily  yielded  up  when  the  liquid  is  agitated  with  air,  or  the  atmospheric 
pressure  is  diminished.  This  property  is  not  possessed  by  a  solution  of  phos- 
phate of  potash  j  and  the  constant  presence  of  a  certain  amount  of  phosphate  of 
soda  in  the  blood,  even  when  none  exists  in  the  food,  which  is  very  significant 
of  its  importance  in  the  economy,  is  explained  by  Prof.  Liebig  by  the  fact,  that 
when  phosphate  of  potash  is  brought  in  contact  with  chloride  of  sodium,  a  double 
decomposition  takes  place,  of  which  phosphate  of  soda  is  one  of  the  products, 
this  remaining  in  the  blood,  whilst  the  potash-salt  is  appropriated  by  the  muscu- 
lar substance  (§  85).s  The  alkaline  phosphates  find  their  way  very  readily  into 

1  See  Prof.  Liebig's  "Familiar  Letters  on  Chemistry,"  letter  xxviii. ;  and  his  "Re- 
searches on  the  Chemistry  of  Food,"  pp.  93,  et  seq. 

•  See  his  "  Researches  on  the  Chemistry  of  Food,"  pp.  113-6. 
»  Ibid,  pp.  104-118. 


INORGANIC  SUBSTANCES.  109 

the  urine ;  and  it  will  be  shown  hereafter  that  a  temporary  augmentation  of 
their  amount  in  that  excretion  is  often  traceable  to  an  unusual  disintegration 
of  Nervous  matter,  setting  free  its  excess  of  phosphorus  in  the  state  of  phos- 
phoric acid.  Where  the  largest  proportion  of  phosphorized  aliment  is  taken, 
there  will  of  course  be  the  largest  proportion  of  phosphatic  salts  in  the  urine ; 
and  thus  it  happens  that  the  urine  of  carnivorous  animals  is  much  more  strongly 
acidified  than  that  of  herbivorous,  and  that  the  urine  of  the  latter  is  often  alka- 
line from  the  abundance  of  bases  and  the  deficiency  of  phosphoric  acid. 

85.  Although  Soda  has  been  spoken  of  as  the  predominant  base  of  the  alka- 
line carbonates  and  phosphates,  yet  the  presence  of  Potash  in  appreciable  quan- 
tity must  not  be  left  out  of  view,  more  especially  as  this  substance  presents 
itself  in  muscle  in  so  much  larger  a  proportion,  that  its  special  relation  to  mus- 
cular tissue  can  scarcely  be  a  matter  of  doubt.     The  following,  according  to 
Prof.  Liebig,1  are  the  relative  amounts  of  Soda  and  Potash  in  the  Blood  and 
Muscle  of  five  different  animals,  the  Soda  being  reckoned  at  100. 

Potash  in  the  Blood.  Potash  in  the  Flesh. 

Fowl      .        .       '.    •".    "j""?;.        .       40.8  384 

Ox          ...        :'*'   ';"•"."  v'.    *    6.9  279 

Horse     .        .        .        V'  VW  (V  < ;  ;J       9.5  285 

Fox        ...     ,^.-,-A.:,,v,-  *>•  214 

Pike       .      .  .  ,**;*wU£^  :fi.,V,?i;*  ^.  ,'  497 

How  far  these  proportions  are  liable  to  be  influenced  by  the  nature  of  the  food, 
and  within  what  limits  they  are  normally  confined,  has  not  yet  been  determined ; 
and  it  is  scarcely  yet  safe,  therefore,  to  found  any  theory  of  disease  upon  a  sup- 
posed excess  or  deficiency  of  the  potash  base.3 

86.  Although  Ammonia  is  found  abundantly  in  excreted  matters,  and  may 
be  regarded  as  one  of  the  ordinary  products  of  the  decomposition  which  is  con- 
tinually taking  place  in  the  living  body,  yet  it  cannot  be  properly  said  to  be  one 
of  its  constituents,  since  it  is  nowhere  found  either  in  the  nutritive  fluids  or  in 
the  living  solids,  so  long  as  they  preserve  their  healthy  state.     Even  in  the 
Urine,  when  freshly  secreted  in  the  state  of  health,  it  is  positively  denied  by 
Prof.  Lehmann  that  Ammonia  exists;  the  precipitate  thrown  down  on  the  addi- 
tion of  bichloride  of  platinum  (which  was  regarded  by  Heintz  as  indicating  its 
presence)  being  really  a  potash  salt.     When  decomposition  commences  in  the 
fluid,  however,  a  large  quantity  of  ammonia  soon  shows  itself;  as  it  does  also 
in  certain  states  of  disease  (CHAP.  xii.  SECT.  3).     Ammonia  seems  to  be  a  nor- 
mal constituent  of  the  cutaneous  and  pulmonary  exhalations;  being  found  in 
the  sweat,  especially  that  of  the  axillae,  and  in  the  halitus  of  the  breath. 

87.  That  Iron  is  a  normal  constituent  of  the  Human  body,  has  been  already 
pointed  out  in  the  account  of  Haematin  (§31).     It  is  not  by  any  means  con- 
fined, however,  to  the  red  corpuscles;  for  it  exists,  though  in  minute  proportion, 
in  the  liquor  sanguinis  in  which  they  float,  and  it  is  found  also  in  various  solid 
tissues.     The  percentage  which  it  forms  of  the  entire  ash  is,  according  to  Rose's 
method,  in  ox-blood  6.84,  in  milk  10.47,  in  yolk  of  egg  1.85,  in  white  of  egg 
2.09,  in  horseflesh  1.00,  in  bile  0.23,  and  in  feces  2.09.     According  to  Von 
Laer,  hair  contains  about  0.4  per  cent,  of  iron,  which  amounts  to  no  less  than 
from  one-ninth  to  one-half  of  the  entire  ash.     The  presence  of  this  substance  in 
such  large  and  constant  amount,  especially  in  the  nutritive  fluids,  shows  that  it 
cannot  be  regarded  as  an  accidental  component;  but  it  must  be  confessed  that 

1  "Researches  on  the  Chemistry  of  Food,"  p.  107. 

2  The  experiments  of  Dr.  Garrod  have  led  him  to  the  conclusion,  that  the  proximate 
cause  of  Scurvy  lies  in  the  deficiency  of  potash  in  the  blood ;  and  that  this  disease  may 
be  successfully  treated  by  the  administration  of  alkaline  medicines  alone.    (See  his  papers 
in  the  "  Lancet"  and  in  the  "Edinb.  Monthly  Journal,"  for  1848.)     A  much  larger  induc- 
tion, however,  is  requisite  for  the  establishment  of  this  position. 


110  CHEMICAL   COMPONENTS   OF   THE   HUMAN   BODY. 

nothing  definite  can  be  predicated  of  its  uses.  These  are  no  doubt  specially 
connected  with  the  function  of  the  red-corpuscles,  whatever  this  may  prove  to 
be ;  and  it  is  an  additional  indication  of  the  coloring-matter  of  the  bile  being 
derived  from  haematin  (§  70),  to  find  that  iron  is  readily  detectable  in  the  for- 
mer substance.  As  almost  every  article  of  ordinary  food,  whether  animal  or 
vegetable,  contains  iron,  its  presence  in  the  system  is  easily  accounted  for. 
Under  ordinary  circumstances,  this  source  will  be  quite  adequate;  but  when 
there  is  a  deficiency  in  the  amount  of  the  red-corpuscles  of  the  blood,  and  it  is 
desirable  to  accelerate  their  production,  the  administration  of  iron  in  a  separate 
form,  especially  in  conjunction  with  a  diet  of  which  animal  flesh  constitutes  a 
large  part,  usually  promotes  their  development. 

88.  The  foregoing  constitute  all  the  inorganic  substances  (in  addition  to  the 
Sulphur  and  Phosphorus  already  spoken  of  in  connection  with  the  protein-com- 
pounds), which  can  be  regarded  as  normal  components  of  the  tissues  and  nutri- 
tious fluids  of  the  Human  body.  There  are  certain  others,  however,  which 
ordinarily  present  themselves  in  the  excretions,  either  as  constituents  of  the 
food  which  are  at  once  rejected,  or  as  results  of  the  chemical  processes  that  take 
place  within  the  system ;  and  which,  though  occasionally  to  be  detected  in  the 
blood,  seem  to  be  present  there  only  as  on  the  road  to  their  outlets.  In  this 
light  we  are  probably  to  regard  the  Alkaline  Sulphates,  which,  although  abun- 
dant in  the  urine,  are  rarely  to  be  detected  in  the  blood,  milk,  bile,  &c.,  except 
by  processes  which  will  oxidize  the  sulphur  they  may  contain,  and  which  will 
consequently  produce  sulphates  that  did  not  exist  there  before.  Even  when 
sulphates  are  taken  into  the  stomach,  it  appears  that  they  are  ordinarily  con- 
verted, in  part  at  least,  into  sulphurets,  in  the  alimentary  canal ;  this  change 
being  due,  as  the  experiments  of  Lehmann  have  shown,  to  the  decomposition 
which  is  going  on  in  the  organic  matters  in  contact  with  the  saline.  Of  that 
which  does  not  undergo  this  conversion,  a  small  quantity  finds  its  way  into  the 
circulation,  to  be  immediately  eliminated  by  the  kidneys;  whilst  the  residue,  if 
large  doses  have  been  given,  passes  off  unchanged  in  the  feces.  When  no  such 
extraneous  source  of  the  sulphates  exists  in  the  solids  or  liquids  ingested,  the 
quantity  of  them  which  is  found  in  the  urine  may  be  considered  as  representing 
an  equivalent  amount  of  sulphur  which  has  been  introduced  into  the  system  in 
combination  with  the  protein-compounds,  and  which  has  been  set  free  and  oxi- 
dized in  the  final  metamorphosis  of  tissue.  The  proportion  is  higher  when  a 
strictly  animal  diet  is  employed,  than  when  the  diet  is  of  the  ordinary  mixed 
character;  and  higher  on  a  mixed,  than  on  a  purely  vegetable  diet.  This  is  just 
what  might  be  anticipated,  from  the  larger  proportion  of  the  sulphurized  com- 
pounds in  animal  flesh. — It  appears  scarcely  requisite  to  mention  Carbonate  of 
Magnesia  under  this  head;  since,  although  it  is  very  commonly  found  in  the 
urine  and  in  the  urinary  concretions  of  herbivorous  animals,  it  is  comparatively 
rare  in  Man.  As  the  magnesia  seems  to  be  introduced  in  the  state  of  phosphate, 
this  carbonate  is  probably  formed  by  double  decomposition  with  some  calcareous 
salt  formed  by  an  organic  acid,  the  lime  being  converted  into  a  phosphate,  and 
the  magnesia  uniting  with  the  organic  acid,  to  be  afterwards  reduced  to  the  state 
of  carbonate. — Under  this  head  may  also  be  noticed  the  Sulphocyanide  of  po- 
tassium which  is  usually  present  in  human  Saliva,  and  which  gives  a  blood-red 
color  to  the  per-salts  of  iron,  that  is  liable  to  be  confounded  with  that  produced 
by  morphia.  As  this  substance  occurs  in  extremely  small  quantity,  and  as  it  is 
frequently  absent  altogether  without  any  concurrent  deficiency  in  the  digestive 
power,  it  cannot  be  regarded  as  an  essential  constituent  of  the  Salivary  secre- 
tion. 

89.  We  have  now,  in  the  last  place,  to  advert  to  the  asserted  presence  of  cer- 
tain Metals,  as  normal  or  occasional  constituents  of  the  Human  body.  That 
which  is  of  the  most  importance  in  a  medico-legal  point  of  view,  is  Arsenic; 


INORGANIC  SUBSTANCES.  Ill 

which  was  at  one  time  maintained  by  Orfila  to  be  constantly  met  with  in  bones. 
That  this  statement  was  erroneous,  has  been  fully  proved  by  subsequent  re- 
searches ;*  and  it  may  be  confidently  asserted  that  the  presence  of  arsenic  in  the 
tissues  can  only  be  attributed  to  its  introduction  into  the  system  in  some  special 
mode.  Even  when  minute  doses  of  arsenic  are  introduced  into  the  body,  as  by 
the  use  of  mineral  waters,  vinegar,  &c.,  containing  this  substance,  they  are 
speedily  eliminated  from  it  by  the  urinary  secretion ;  so  that  the  metal  does 
not  accumulate  in  the  tissues.  It  is  only  when  introduced  more  rapidly  than 
the  system  can  carry  it  off,  that  it  exhibits  its  deleterious  effects  upon  the  eco- 
nomy, and  that  it  is  detectable  in  the  solid  tissues.  Thus  Dr.  Letheby  has 
shown  that  poisonous  doses  of  arsenic  may  be  repeatedly  administered  to  animals, 
without  the  usual  injurious  consequences,  if  diuretics  be  given  at  the  same  time 
so  as  to  occasion  an  unusual  activity  in  their  elimination.  When  even  a  sin- 
gle dose  has  been  administered,  however,  sufficiently  potent  to  occasion  death, 
arsenic  may  very  frequently  be  detected  in  the  liver  and  kidneys  (the  excreting 
organs  towards  which  it  is  specially  determined),  and  sometimes  also  in  the  heart, 
lungs,  brain,  and  muscles. — The  frequent  presence  of  Copper  in  the  liver  of 
Man,  and  in  the  bile  and  biliary  concretions,  may  now  be  regarded  as  a  well- 
established  fact  in  Animal  Chemistry ;  but  it  is  not  hence  to  be  concluded  that 
this  metal  is  a  normal  constituent  of  his  body.  On  the  contrary,  there  is  valid 
reason  to  believe  that,  when  introduced  in  small  quantities,  either  by  its  presence 
in  the  food  or  drink  ingested,  or  by  the  accidental  contamination  of  these  by  the 
utensils  employed  in  their  preparation,  copper  is  removed  by  the  excretory  ap- 
paratus, the  liver  affording  the  special  channel  for  its  elimination.  It  is  inte- 
resting to  remark  that  copper  appears  to  be  a  normal  constituent  of  the  blood  of 
some  marine  Invertebrated  animals  (both  Molluscous  and  Articulated),  where 
it  seems  to  replace  iron.2 — The  presence  of  Lead  in  the  tissues  and  fluids  of  the 
Human  body  would  seem  to  be  far  more  frequent  j  yet  it  is  not  entitled  to  rank 
as  a  normal  component  of  the  organism.  Lead  is  pre-eminently  cumulative  in 
its  tendencies ;  that  is,  when  it  has  been  introduced  into  the  circulation  in  small 
quantities,  the  excreting  organs  make  little  effort  to  remove  it,  and  it  is  depo- 
sited in  the  tissues.  Thus  it  happens  that  the  habitual  ingestion  of  even  very 
minute  quantities  of  this  metal,  will,  if  continued  for  a  sufficient  length  of  time, 
give  rise  at  last  to  the  most  severe  symptoms ;  and  that  the  entire  body  seems 
to  be  then  charged  with  the  poison,  which  may  especially  fix,  however,  upon 
particular  muscles,  or  groups  of  muscles,  which  it  paralyzes,  and  in  whose  sub- 
stance it  is  deposited  in  very  sensible  amount.  In  the  treatment  of  such  cases,  it 
is  a  matter  of  the  greatest  importance  to  obtain  the  elimination  of  the  poison 
through  the  excretory  organs ;  and  it  does  not  appear  that  either  the  liver  or 
the  kidneys  can  be  acted  on  for  this  purpose  so  effectually  as  the  skin,  through 
which  the  lead  may  be  drawn  forth  in  large  quantities  by  means  of  warm  sul- 
phurous baths.3  That  the  kidneys,  however,  do  serve  as  channels  for  its  removal, 
is  proved  by  the  detection  of  lead  in  the  urine,  by  hydrosulphate  of  ammonia; 
and  it  seems  to  be  to  its  power  of  rendering  lead  soluble,  and,  at  the  same  time, 
to  its  stimulation  of  the  kidneys  to  increased  action,  so  as  to  eliminate  the 

1  See  the  Report  on  this  subject,  made  by  a  Committee  of  the  French  Institute  in  1841. 
The  medical  witness,  however,  who  is  called  on  to  speak  as  to  the  presence  of  arsenic  in 
the  tissues,  may  expect  to  be  severely  questioned  as  to  this  point  by  an  opposing  counsel, 
and  should  be  prepared  with  his  negative  evidence. 

2  It  is  affirmed  by  Millon,  that  copper  may  be  detected  in  human  blood ;  but  his  con- 
clusions have  been  controverted  by  Melsens.     See  "Ann.  de  Chim.  et  de  Phys.,"  Sieme 
ser.  torn,  xxiii.  pp.  358-372. 

3  See  a  highly  interesting  case  of  Chronic  Lead  Poisoning,  in  which  this  remedy  was 
most  effectually  employed,  in  the  "Dublin  Quarterly  Journal  of  Medical  Science,"  vol. 
vii.  p.  415. 


112  CHEMICAL   COMPONENTS   OF   THE   HUMAN   BODY. 

soluble  compound,  that  we  are  to  attribute  the  good  effects  which  have  been 
obtained  from  the  use  of  iodide  of  potassium  in  removing  Lead  from  the  system. 

7.   General  Summary. —  Operation  of  Chemical  Forces  in  the  Living  Body. 

90.  We  have  now  passed  in  review  the  chief  among  those  components  of  the 
Human  body — whether  presenting  themselves  in  its  nutritive  fluids,  in  its  solid 
tissues,  or  in  its  excretory  products — whose  existence  has  been  made  definitely 
known  by  Chemists.     It  is  by  no  means  to  be  assumed  that  what  has  here  been 
stated  affords  a  complete  list  of  the  chemical  components  of  this  fabric;  still 
less,  that  the  account  which  has  been  given  of  the  metamorphoses  they  undergo, 
is  to  be  received  in  the  light  of  a  determinate  scheme.    We  should,  indeed,  regard 
it  as  a  mere  sketch  or  outline,  in  which  the  broad  features  are  conveyed  with 
tolerable  distinctness,  but  of  which  the  details  remain  to  be  filled  in  by  careful 
study.     And  the  greatest  advantage  which  can  be  derived  from  this  method  of 
viewing  the  subject,  consists  in  the  more  definite  boundary  we  are  enabled  to 
draw  between  what  is  known  and  what  is  unknown,  and  again,  between  what 
rests  on  a  fair  basis  of  probability,  and  what  has  no  better  foundation  than  vague 
surmise.     Moreover,  there  is  an  obvious  advantage  in  combining  the  chemical 
and  the  physiological  view  of  the  facts  in  question.     For  the  mere  Chemist  will 
not  only  be  liable  to  continual  error,  when  he  attempts  to  reason  as  to  what 
takes  place  in  the  penetralia  of  the  living  body  from  what  he  observes  in  his 
laboratory,  without  taking  into  account  the  difference  in  the  conditions  of  the 
phenomena  (of  which  kind  of  error  some  of  the  speculations  of  Prof.  Liebig  have 
afforded  remarkable  examples) ;  but  he  will  also  be  at  a  great  disadvantage  in 
the  prosecution  of  his  inquiries,  for  want  of  the  guiding  clue  which  Physiologi- 
cal knowledge  alone  can  afford.     On  the  other  hand,  the  Physiologist  cannot 
safely  make  a  step  in  advance,  when  engaged  in  the  study  of  the  metamorphoses 
of  the  alimentary  materials  into  the  living  solids,  and  of  the  subsequent  reduc- 

-  tion  of  the  latter  to  the  condition  of  excrementitious  matters,  without  relying 
on  those  exact  data  which  Chemical  tests  and  analyses  can  alone  supply ;  it 
being  to  these,  in  fact,  that  he  owes  whatever  definite  knowledge  he  possesses 
of  the  composition  of  these  several  bodies,  with  which  it  is  of  -the  most  funda- 
mental importance  that  he  should  be  acquainted.  Accordingly,  all  the  most 
productive  researches  of  recent  times,  in  this  department,  have  been  the  work 
of  men,  who  have  either  combined  within  themselves  these  two  kinds  of  know- 
ledge, or  who  have  brought  them  to  bear  upon  one  another  from  extraneous 
sources. 

91.  The  following  Summary  is  intended  to  convey,  within  a  narrow  compass, 
the  leading  conclusions,  in  regard  to  the  Chemistry  of  the  living  Body,  to  which 
the  Chemico-physiological  labors  of  recent  times  appear  to  point. 

I.  The  organic  materials  indispensable  for  the  genesis  of  Tissue,  consist  of 
Albuminous  and  Fatty  compounds. — The  former  present  themselves  under  various 
aspects,  in  the  Vegetable  as  well  as  in  the  Animal  kingdom,  all  being  reducible, 
however,  to  the  ordinary  state  of  Albumen  by  the  digestive  process ;  and  in 
their  natural  states  of  combination,  they  include  most  of  the  inorganic  substances 
which  are  required  in  addition.     There  is  no  reason  whatever  to  believe,  that 
Albuminous  compounds  can  be  generated  within  the  animal  body,  by  the  trans- 
formation of  substances  belonging  to  an  entirely  different  type. — The  latter  are 
directly  afforded  by  ordinary  animal  food,  and  by  many  kinds  of  vegetable  pro- 
ductions ;  and  it  seems  to  be  when  they  are  thus  supplied,  that  they  are  most 
readily  made  available  in  histogenesis.     They  may  be  produced  within  the  body, 
however,  by  the  metamorphosis  of  either  Albuminous  or  Saccharine  compounds. 

II.  The  great  mass  of  those  tissues  of  the  body  which  belong  to  the  cellular 
type,  is  generated  at  the  expense  of  Albuminous  matter ;  fat-particles,  however, 


OPERATION   OF   CHEMICAL   FORCES   IN   THE   LIVING   BODY.      113 

being  intimately  blended  with  this  in  an  early  stage  of  their  formation.  Of 
this  we  have  a  notable  example  in  the  case  of  Muscular  tissue ;  but  the  cell- 
walls  of  all  other  textures  would  be  found,  if  they  could  be  entirely  freed  from 
their  contents,  to  have  the  same  composition.  Even  if  they  be  altogether  chemi- 
cally identical,  however,  the  molecular  condition  of  the  particles  composing  the 
amorphous  coagulum  and  the  living  cell  must  be  entirely  different;  and  the 
latter  exhibits  distinctive  vital  properties,  in  virtue  of  the  organizing  process  to 
which  its  material  has  been  subjected.  Not  merely  the  cell-walls,  but  the  cell- 
contents  of  these  tissues  (with  the  exception  of  those  concerned  in  the  act  of 
excretion),  seem  to  be  derived  from  the  Albuminous  or  from  the  Fatty  constitu- 
ents of  the  blood :  this  seems  clear,  for  example,  in  regard  to  the  globulin  and 
hsematin  of  the  red  corpuscles  of  the  blood,  and  the  horny  matter  of  the  epider- 
mis and  its  appendages,  which  must  have  their  source  in  the  former  ;  and  also 
with  respect  to  the  contents  of  the  adipose  and  nervous  vesicles,  which  must  be 
drawn  wholly  or  in  part  from  the  latter.  Whether,  in  the  construction  of  the 
tissues  of  this  class,  the  Albumen  of  the  blood  may  serve  directly  as  the  pabulum 
for  the  production  of  cells,  or  whether  it  must  needs  pass  first  through  the  con- 
dition of  Fibrin,  cannot  be  distinctly  affirmed  ;  there  is  no  positive  evidence  in 
support  of  either  proposition ;  but  the  probabilities  appear  to  the  Author  on  the 
whole  to  favor  the  former  view. 

in.  The  great  mass  of  the  gelatigenous  tissues  of  the  body,  whose  texture  is 
simply  fibrous,  is  also  derived  from  the  albuminous  element  of  the  Blood;  but 
this  passes  through  the  intermediate  condition-  of  Fibrin,  which  may  be  regarded 
as  a  substance  endowed  with  the  power  of  self-development  into  a  low  form  of 
organized  structure,  and  therefore  as  having  already  undergone  a  vitalizing  in- 
fluence. There  is  no  sufficient  reason  to  believe  that  Gelatin  employed  as  food 
can  ever  be  applied  even  to  this  purpose  in  the  body ;  since  all  that  we  know  of 
the  genesis  of  the  simple  fibrous  tissues  indicates  that,  in  assuming  their  charac- 
teristic structure,  they  pass  through  gradations  similar  to  those  which  we  witness 
in  the  production  of  the  adventitious  tissue  of  fibrinous  exudations. 

IV.  When  the  death  and  disintegration  of  the  tissues  again  bring  their  com- 
ponents under  complete  subjection  to  Chemical  forces,  an  entirely  different  series 
of  metamorphoses  takes  place,  tending  to  degrade  these  components  towards  the 
condition  of  inorganic  compounds.  They  would  seem  to  resolve  themselves  into 
two  classes  of  substances ; — on  the  one  hand,  saccharine,  oleaginous,  and  resin- 
ous matters,  analogous  to  those  of  plants,  in  which  carbon  predominates  ; — on 
the  other,  a  set  of  compounds  peculiar  to  animals,  of  which  nitrogen  is  the  cha- 
racteristic ingredient.  From  the  albuminous  constituent  of  muscle,  for  example, 
there  is  direct  evidence  that  fat,  sugar,  and  lactic  acid  may  be  generated  on  the 
one  hand;  on  the  other,  creatine,  and  (probably  through  this  creatine)  urea, 
with  the  rest  of  the  highly-azotized  components  of  the  urinary  excretion.  The 
sugar  generated  by  the  agency  of  the  liver,  from  the  products  of  the  waste  or 
disintegration  of  the  system  that  are  contained  in  the  blood,  seems  to  be  at  once 
employed  in  supporting  the  combustive  process  by  which  the  animal  heat  is 
maintained.  The  fat  may  be  directly  applied  to  the  same  purpose,  or  may  be 
stored  up  in  the  cells  of  Adipose  tissue  for  future  use.  The  peculiar  resinous 
acids  of  the  bile,  which  are  probably  formed  from  the  same  source,  appear  to 
fulfil,  in  part  at  least,  a  similar  destination,  after  having  been  made  subservient 
to  other  purposes.  The  lactic  acid,  chiefly  generated  in  the  substance  of  the 
muscles  (probably  by  the  metamorphosis  of  a  saccharine  compound,  which  may 
be  looked  on  as  the  immediate  product  of  their  disintegration),  is  in  like  man- 
ner destined  to  be  carried  off  by  the  respiratory  process,  though  a  part  of  it 
may  first  be  rendered  subservient  to  the  digestive  operation.  But  if  the  respira- 
tory process  should  not  be  sufficiently  active  to  remove  these  highly-carbonized 
compounds  from  the  blood,  we  may  find  the  lactic  and  hippuric  acids  in  the  urine, 
8 


114  CHEMICAL   COMPONENTS   OF   THE   HUMAN   BODY. 

with  the  addition  of  carbonaceous  pigmentary  matter.  On  the  other  hand,  the 
highly-azotized  substances  are  destined  for  immediate  elimination  by  the  kid- 
neys ;  their  presence  in  the  current  of  the  circulation  being  so  hurtful,  that 
even  a  small  amount  of  accumulation  might  induce  fatal  results. 

V.  Besides  the  foregoing  substances,  there  are  doubtless  others  which  have 
not  been  so  carefully  studied,  and  which  are  passed  off  by  distinct  channels. 
Thus,  we  have  no  precise  knowledge  of  those  products  of  disintegration  which 
are  thrown  off  by  the  skin ;  and  the  proper  fecal  matter,  which  is  undoubtedly 
derived  from  some  excretion  poured  into  the  alimentary  canal,  rather  than  from 
putrescent  changes  in  the  residue  of  the  substances  which  are  passing  through 
it,  has  not  yet  been  made  the  subject  of  accurate  examination. 

vi.  Where  more  alimentary  matter  is  introduced  into  the  blood  than  is  re- 
quired for  the  genesis  of  living  tissue,  this  probably  undergoes  the  same  decom- 
posing changes,  as  do  the  effete  matters  that  are  set  free  by  the  disintegration 
of  the  organized  fabric.  The  saccharine  and  oleaginous  matters  are  directly 
carried  off  by  the  combustive  process,  only  that  portion  being  applied  to  the  pro- 
duction of  adipose  tissue  which  may  not  be  required  for  the  maintenance  of  the 
temperature  of  the  body ;  whilst  the  albuminous  and  gelatinous  appear  to  be 
resolved  into  the  two  classes  of  compounds  already  indicated,  part  of  which  are 
eliminated  by  the  liver  and  lungs,  the  other  part  chiefly  by  the  kidneys,  but 
also  by  the  skin  and  (its  internal  reflexion)  the  alimentary  canal.  It  may  here 
be  mentioned,  as  an  additional  evidence  of  the  production  of  sugar  from  albumi- 
nous compounds  within  the  living-  body,  that  it  is  found  in  the  milk  of  Carnivo- 
rous animals,  which  have  been  for  some  time  restricted  to  a  diet  of  animal 
flesh.1  r;v 

Our  data  are  at  present  far  too  imperfect  to  allow  this  series  of  metamorphoses  to  be 
definitely  represented  by  the  aid  of  formulae ;  nevertheless,  there  are  certain  general  rela- 
tions which  have  a  real  existence,  and  which  may  be  appropriately  indicated  in  this  mode. 
The  following  are  given  by  Prof.  Liebig  ("Familiar  Letters  on  Chemistry,"  p.  439),  as 
examples  of  the  transformations  which  may  occur;  it  is  to  be  observed,  however,  that 
some  of  the  formulae  which  he  employs  (op.  cit.,  p.  437)  differ  from  those  in  com- 
mon use. 

1  equiv.  of  Albumen  with  10  equivs.  of  Water,  contains  the  elements  of  2  equivs.  of 
Glutin  and  1  equiv.  of  Choleic  (tauro-cholic)  acid,  thus — 

C.       H.      N.     0.    S.  C.       H.      N.     0.     S. 

1  Albumen  ==  216     169     27     68     %  ]        f  164     134     26     64        =2  Glutin. 
10  Water       =  10  10  52       45       1     14    2  =  1  Choleic  acid. 


216     179    27     78    2J        [216     179    27     78    2 

1  equiv.  of  Fibrin  of  Blood  with  8  equivs.  of  Water  contains  the  elements  of  1  equiv.  of 
Glutin  and  1  equiv.  of  Albumen. 

C.        H.       N.      < 

1  Fibrin  =  298      228      40      92      2]        f216     169      27     68       2  =  1  Albumen. 
8  Water  =  8  8  82       67      13      32  =1  Glutin. 


298      236    40     100      2J        [298     236      40    100       2 

1  equiv.  of  Casein  with  10  equivs.  of  Oxygen  contains  the  elements  of  1  equiv.  of  Albu- 
men and  1  equiv.  of  Chondrin. 

S. 

1  Casein     =288     228     86     90    2]        f216     169      27      68       2  =  1  Albumen. 
10  Oxygen  =  10  72       59        9      32  =  1  Chondrin. 


288     228     36  100    2  288     228     36     100      2 


1  This  was  at  one  time  denied  by  Dumas ;  but  the  fact  has  been  fully  established  by  the 
researches  of  Bensch,  who  has  also  explained  the  reason  of  Dumas' s  failure  to  detect  the 
presence  of  sugar.  (See  •''Ann.  der  Chem.  und  Pharm.,"  band  Ixi.  p.  221.) 


OPERATION   OF   CHEMICAL   FORCES   IN   THE   LIVING   BODY.       115 

The  three  preceding  formulae  represent  such  metamorphoses  as  may  occur  in  the  genesis 
of  tissues ;  the  following  represent  some,  of  those  which  may  take  place  in  their  disinte- 
gration, in  which  (it  must  be  remembered)  oxygen  drawn  from  the  air  performs  an  im- 
portant part. 

1  equiv.  of  Albumen  with  10  equivs.  of  Water  and  56  equivs.  of  Oxygen  contains  the 
elements  of  1  equiv.  of  Choleic  (tauro-cholic)  acid,  2  equivs.  of  Cholic  (glyco-cholic)  acid, 
12  equivs.  of  Urea,  and  36  equivs.  of  Carbonic  acid. 

C.       H.     N.     0.   S.  C.      H.      N.    0.     S. 

52     45       1     14    2  =  1  Choleic  acid. 


1  Albumen  =  216     169     27     68 
10  Water       =  10  10 

56  Oxygen     =  56 


216     179     27  134    2J 


104     86       2     24        =2  Cholic  acid. 
24    48     24    24        =  12  Urea. 
36  72         =  36  Carbonic  acid. 


216  179    27  134    2 


1  equiv.  of  Glutin  with  10  equivs.  of  Oxygen  contains  the  elements  of  1  equiv.  of  Cholic 
(glyco-cholic)  acid,  3  equivs.  of  Uric  acid,  and  12  equivs.  of  Water. 

C.  H.  N.  0.  C.  H.  N.  0. 

i   m  *•              QO  «?  IQ  QO  1  f52  43  1  12  =  1  Cholic  acid. 

IGlutm     =82  67  13  32  3Q  12  12  18  ^  8  Uric  acid. 

10  Oxygen   =  10  I  I  12  =  12  Water. 


82     67     13    42  J        [82     67  13  42 

1  equiv.  of  Chondrin  contains  the  elements  of  one  Cholic  (glyco-cholic)  acid,  2  Uric 
acid,  and  8  Water. 

C.     H.    N.     0.  C.     H.  N.  0. 

52     43  1  12  =  1  Cholic  acid. 

1  Chondrin  =  72     59     9     32  \  =  \  20       8  8  12  =  2  Uric  acid. 

8  8  =  8  Water. 


72     59     9     32 

Now  although  it  must  be  admitted  that,  by  a  dexterous  management  of  formulae,  almost 
any  kind  of  transformation  may  be  effected  on  paper,  yet  the  above  coincidences  are  so  re- 
markable in  themselves,  and  are  so  closely  accordant  with  phenomena  of  whose  occur- 
rence we  have  independent  evidence,  that  it  seems  hardly  just  to  regard  them  as  merely 
fortuitous. 

Vii.  The  Inorganic  acids,  bases,  and  saline  compounds,  which  properly  rank 
as  constituents  of  the  body,  are  for  the  most  part  applied  to  its  construction  in 
the  forms  in  which  they  were  introduced  from  the  food;  and  they  reappear 
under  the  same  forms  in  the  excretions.  But  new  compounds  are  also  pro- 
duced during  the  progress  of  the  metamorphic  changes  already  referred  to. 
Thus,  a  portion  of  the  sulphur  taken  in  as  a  constituent  of  albuminous  food, 
seems  to  be  oxidized  in  the  final  disintegration  of  the  tissues  by  which  that 
albumen  was  appropriated,  and  is  converted  into  sulphuric  acid ;  a  part,  how- 
ever, still  remaining  unoxidized,  and  passing  off  in  that  state,  both  by  the  bile 
and  the  urine.  So,  again,  if  phosphorus  (as  such)  be  a  constituent  of  the  pro- 
tein-compounds, or  be  united  with  fatty  matters,  it  must  undergo  a  similar  oxi- 
dation within  the  system;  as  it  scarcely  ever  presents  itself  in  the  excretions 
under  any  other  form  than  that  of  phosphoric  acid.  On  the  other  hand,  by 
the  oxidation  of  various  organic  acids  largely  contained  in  vegetable  food,  their 
alkaline  bases  are  reduced  to  the  state  of  carbonates,  so  as  to  be  ready  to  com- 
bine with  any  of  the  stronger  acids  that  may  be  present  in  the  system;  and 
ammonia  seems  also  to  be  generated  d&  novo.  Thus  a  supply  of  bases  is  pre- 
pared, ready  to  neutralize  not  merely  the  acids  whose  mode  of  production  has 
just  been  described,  but  also  the  uric,  hippuric,  and  lactic  acids  which  are  gene- 
rated within  the  body,  and  which  do  not  readily  pass  off  from  it  except  in  com- 
bination with  bases;  and  according  as  the  proportion  of  these  bases  is  equivalent 
to  that  of  the  acids;  exceeds  it,  or  is  exceeded  by  it,  will  the  urine  be  neutral, 


116  CHEMICAL   COMPONENTS   OF   THE   HUMAN   BODY. 

alkaline,  or  acid. — When  mineral  substances,  whose  presence  is  superfluous  or 
noxious,  are  introduced  into  the  body,  an  effort  is  usually  made  for  their  elimi- 
nation, by  some  of  the  excretory  organs;  most  commonly  by  the  kidneys. 

92.  There  is  very  strong  evidence  that,  in  all  these  transformations,  Chemical 
forces  are  alone  concerned;  this  evidence  arising,  on  the  one  hand,  from  the 
nature  of  the  changes  themselves;  and,  on  the  other,  from  the  certainty  that 
such  forces  must  be  in  operation,  and  that  their  effects  will  be  modified  by  the 
peculiar  conditions  under  which  they  are  exerted.  We  have  already  seen  that 
many  of  the  changes  taking  place  within  the  living  body  can  be  precisely  imi- 
tated out  of  it,  by  the  use  of  means  whose  actual  operation  is  of  the  same  kind, 
though  the  modus  operandi  may  be  very  different.  Of  this  a  remarkable  ex- 
ample is  afforded  by  the  process  of  oxidation,  which  is  continually  going  on 
within  the  system,  and  which  produces  a  most  important  influence  on  the  con- 
dition of  the  products  of  its  disintegration.  When  the  Chemist  desires  to  con- 
vert one  organic  compound  into  another  by  oxidation,  he  treats  it  with  some 
substance  (e.  g.  nitric  acid  or  peroxide  of  lead)  which  readily  yields  oxygen ; 
whereas,  the  Physiological  method  is  altogether  different,  for  the  substance  to  be 
acted  on,  being  diffused  through  the  circulating  fluid,  is  exposed  to  the  direct 
influence  of  the  oxygen  of  the  air,  in  a  state  of  almost  infinitely  minute  division, 
during  the  passage  of  that  fluid  through  the  multitudinous  capillary  channels 
of  the  lungs.  Now  of  the  efficacy  of  this  state  of  subdivision,  in  bringing 
about  changes  which  do  not  occur  when  the  substances  to  whose  attractive 
forces  these  are  due  are  simply  exposed  to  each  other  en  masse,  we  have  a  very 
remarkable  example  in  the  fact  that  iron,  when  reduced  from  the  oxide  to  the 
metallic  state  by  a  current  of  hydrogen  gas,  and  thus  left  as  a  very  fine  powder, 
becomes  spontaneously  ignited  by  exposure  to  common  air,  and  oxidizes  as 
rapidly  as  a  piece  of  iron-wire  would  do  when  burned  in  pure  oxygen  or  im- 
mersed in  nitric  acid.  This  point  has  scarcely  been  sufficiently  attended  to  by 
Chemists,  who  have  too  readily  satisfied  themselves  with  accounting  for  such 
metamorphoses  by  laboratory  operations,  without  inquiring  how  far  similar 
agencies  could  be  at  work  within  the  body :  and  we  shall  hereafter  find  that  this 
powerful  oxidizing  process  is  probably  employed,  not  merely  in  the  combustion 
of  materials  introduced  into  the  body,  or  supplied  from  itself,  for  the  mainte- 
nance of  its  heat,  nor  only,  in  addition,  for  the  removal  of  some  of  the  products 
of  its  own  disintegration,  but  also  for  the  decomposition  and  elimination  of 
certain  organic  poisons,  from  which,  when  they  have  been  introduced  into  the 
body  from  without,  it  is  freed  through  this  channel,  as  it  is  from  many  of  those 
of  a  mineral  nature  through  the  kidneys. — Allusion  has  already  been  made, 
again,  to  the  peculiar  action  of  ferments  (§  19),  which  tend  to  produce  new 
arid  simpler  arrangements  of  the  elements  of  organic  compounds,  such  as  no 
ordinary  reagents  could  effect.  And  it  has  been  also  pointed  out  that  the  very 
same  substance  in  different  stages  of  decomposition  may  occasion  the  genesis  of 
several  different  sets  of  new  compounds,  according  to  the  state  in  which  it  may 
itself  happen  to  be  when  employed  for  this  purpose.  Moreover,  it  has  been 
also  seen,  in  how  very  marked  a  degree  the  condition  and  the  metamorphoses  of 
organic  compounds  are  effected  by  the  presence  of  very  small  quantities  of  in- 
organic substances;  but  whether  their  influence  be  that  of  ordinary  chemical 
attraction,  or  that  which  has  been  termed  "catalytic"  power,  cannot  yet  be 
positively  stated. — It  is  to  be  remembered,  moreover,  that  the  circulating  fluid, 
which  is  probably  the  seat  of  most  of  these  metamorphoses,  is  itself  in  a  state 
of  constant  change ;  that  new  components  are  continually  being  introduced,  on 
the  one  hand  from  the  alimentary  materials,  and  on  the  other  from  the  disinte- 
gration of  the  tissues;  and  that  such  a  condition  must  be  eminently  favorable 
to  the  chemical  metamorphosis  of  its  organic  constituents. — It  may  be  remarked, 
moreover,  that  the  mode  in  which  capillarity  is  brought  into  action  in  the  pro- 


OPERATION   OF   CHEMICAL   FORCES   IN   THE   LIVING   BODY.       117 

cesses  of  nutrition,  is  likely  to  have  an  important  influence  in  determining 
further  chemical  changes,  in  virtue  of  the  galvanic  action  which  may  thus  be 
set  up;  it  having  been  shown  by  Becquerel  that,  if  the  bend  of  a  siphon  be 
filled  with  fine  sand,  and  an  acid  be  poured  into  one  leg  and  an  alkaline  solution 
into  the  other,  the  chemical  action  which  ensues  at  their  point  of  meeting  will 
give  rise  to  a  galvanic  current  between  the  contents  of  the  two  legs,  when  these 
are  connected  by  a  wire  passing  from  one  to  the  other  through  the  open  ends  of 
the  siphon.  As  the  blood  and  the  tissues  are  continually  acting  chemically  on 
one  another  through  the  permeable  walls  of  the  vessels,  it  is  scarcely  possible 
but  that  electric  currents  should  be  thus  generated;  and  it  seems  very  probable 
that  these  may  perform  an  important  part  in  the  metamorphoses  in  question. 

93.  On  the  whole  it  may  be  confidently  affirmed,  that  of  the  changes  which 
have  been  described  in  the  present  chapter,  there  are  none — save  the  production 
of  Fibrin,  whose  peculiarly  vital  properties  have  been  already  dwelt  on  (§  29) — 
which  there  is  any  adequate  reason  to  attribute  to  other  than  Chemical  agencies ; 
for  if  all  cannot  yet  be  precisely  imitated  by  laboratory  processes,  this  imitation 
has  been  successfully  practised  in  the  case  of  a  large  number  of  them  ;  and  the 
nature  of  the  remainder  is  such  as  leaves  it  by  no  means  improbable  that  they 
too  will  be  reduced  to  the  same  category.     In  treating  of  this  subject,  it  would 
be  very  easy  to  obtain  a  temporary  solution  of  all  difficulties  of  this  kind,  by 
regarding  every  case  not  otherwise  explicable  as  a  manifestation  of  "  vital  force ;" 
but  such  a  method  is  altogether  inconsistent  with  sound  philosophy ;  and  we 
have  no  right  to  call  in  the  assistance  of  vital  force  on  any  other  occasion  than 
when  we  witness  phenomena  which  are  not  only  inexplicable  by,  but  altogether 
inconsistent  with,  the    known  operations   of  Physical   and    Chemical    forces. 
Phenomena  of  this  kind  will  hereafter  come  under  our  consideration ;  but  none 
such  (with  the  single  exception  just  referred  to)  have  yet  fallen  under  our  notice; 
the  metamorphoses  we  have  been  considering  being  mere  changes  in  composition, 
analogous  to  those  which  have  been  effected  in  the  laboratory;  and  the  elements 
alike  of  the  original  substances,  and  of  the  products  of  their  changes,  being 
held  together  by  affinities  in  which  Life  has  obviously  no  concern. — It  is  not 
here  denied,  however,  that  Vital  Force  has  an  influence  upon  the  Chemical  phe- 
nomena of  the  body;  on  the  contrary,  much  evidence  will  be  hereafter  given, 
that  such  an  influence  is  exerted,  especially  through  the  nervous  system.     But 
this  agency  may  be  considered  to  operate,  after  the  manner  of  Electricity  or 
Heat,  in  modifying  the  play  of  ordinary  Chemical  attractions,  rather  than  in 
substituting  for  them  a  new  set  of  "vital  affinities." 

94.  The  highest  estimate,  however,  that  we  seem  justified  in  making,  of  the 
play  of  Chemical  Affinities  in  the  living  body,  is  applicable  only  to  those  trans- 
formations, which,  on  the  one  hand,  prepare  the  pabulum  for  that  Organizing 
process,  whereon  is  dependent  the  development  of  vital  properties  in  substances 
that  were  previously  inert;  and  which,  on  the  other,  minister  to  the  application 
of  the  effete  matters,  resulting  from  the  disintegration  of  tissues  whose  term  of 
life  is  over,  to  purposes  that  are  advantageous  to  the  system  in  general,  or  are 
subservient  to  their  removal  in  the  most  effective  manner  from  the  economy,  to 
whose  operations  their  continued  presence  would  be  prejudicial.     Thus  the  re- 
duction of  all  the  protein  compounds  to  the  condition  of  Albumen,  in  the  diges- 
tive process,  and  the  introduction  of  this  substance  into  the  blood  in  its  soluble 
form,  can  be  accounted  nothing  else  than  a  purely  chemical  operation.     The 
same  may  be  said  of  the  conversion  of  starch  into  sugar,  and  of  sugar  into 
fatty  matter.     It  may  be  surmised,  moreover,  that  the  production  of  globulin 
and  of  haematin  from  albuminous  material,  may  be  due  to  chemical  actions  de- 
termined by  the  vital  agency  of  the  floating  cells  of  the  blood,  in  the  manner 
indicated  in  the  preceding  paragraph.     And  the  same  may  be  true  of  the  change 
of  composition  (if  any  difference  really  exists),  which  is  a  part  of  the  metamor- 


118  CHEMICAL  COMPONENTS   OF   THE   HUMAN   BODY. 

phosis  of  albumen  into  fibrin;  and  of  that  still  more  decided  change  which 
subsequently  takes  place,  when  the  fibrous  tissues  are  converted,  in  the  act  of 
formation,  into  the  substance  which  yields  gelatin.  For,  as  already  pointed  out, 
although  the  Chemist  has  not  yet  succeeded  in  imitating  this  metamorphosis, 
yet  there  are  circumstances  which  indicate  that  such  a  fundamental  relation  ex- 
ists between  the  protein-compounds  and  gelatin  as  leaves  no  right  to  assume 
that  any  other  than  chemical  forces  are  concerned  in  it. 

95.  But  with  the  changes  directly  concerned  in  the  development  of  living 
tissue,  Chemistry  would  seem  to  have  nothing  whatever  to  do.     The  substance 
of  Muscle,  for  example,  is  chemically  the  same  with  the  Albumen  of  the  blood ; 
and  the  whole  difference  between  the  organized  structure   possessed  by  the 
former  and  the  amorphous  coagulum  formed  by  the  latter,  between  the  marvel- 
lous activity  of  the  one  and  the  passive  inertness  of  the  other,  must  be  attributed 
to  Vital  force  alone.     Now  it  is  one  of  the  chief  peculiarities  of  this  Vital  force, 
that  it  is  able,  so  long  as  it  is  capable  of  being  fully  exerted,  to  resist  and  keep 
at  bay  the  influence  of  those  Chemical  and  Physical  forces,  which  would  tend, 
were  it  not  for  this  property  of  the  living  substance,  to  effect  its  speedy  disinte- 
gration and  decay.     Of  this  we  have  a  most  characteristic  and  apposite  example, 
in  the  case  of  a  seed  that  has  been  brought  to  the  surface  of  the  soil,  after  hav- 
ing been  buried  for  a  long  lapse  of  years  or  centuries  in  the  earth.     Whilst  it 
remained  in  complete  seclusion  from  moisture  and  oxygen,  and  was  kept  at  a 
low  temperature,  no  appreciable  alteration  took  place  in  it ;  but  so  soon  as  it  is 
exposed  to  warmth,  and  to  the  contact  of  air  and  water,  it  must  begin  to  change 
— its  passive  existence  giving  place  to  a  state  either  of  growth  or  of  decay, 
according  as  it  has  retained,  or  has  lost,  its  vital  properties.     For  the  very 
agents  which  are  most  effectual  in  stimulating  it  to  vital  activity,  and  which 
afford  the  conditions,  dynamical  and  material,  whereby  the  seed  develops  itself 
into  the  plant,  are  those  which,  if  the  seed  be  no  longer  capable  of  germination, 
most  favor  its  decay,  reducing  its  organic  components  back  to  the  condition  of 
inorganic  compounds.     This  peculiar  attribute  of  living  substances  will  be  more 
fully  considered  in  the  next  Chapter. 

96.  Immediately,  however,  that  we  pass  the  confines  of  Life,  we  re-enter  the 
domain  of  Chemistry ;  for  so  soon  as  the  vital  activity  of  the  living  tissues  has 
ceased,  their  materials  again  become  entirely  subject  to  Chemical  forces ;  and 
all  the  metamorphoses  which  we  have  been  occupied  in  tracing  out — tending, 
as  they  do,  to  reduce  the  organic  compounds  with  which  they  commence,  lower 
and  lower  in  the  scale,  until  these  are  restored  to  the  forms  of  simple  binary 
composition  from  which  their  elements  were  at  first  derived — can  scarcely  be 
regarded  in  any  other  light  than  as  the  result  of  ordinary  Chemical  agencies. 
Thus,  then,  according  to  the  view  here  advocated,  the  Life  of  each  part  is  de- 
pendent upon  Chemical  operations,  in  so  far  as  it  is  by  these  that  its  nutrient 
materials  are  prepared,  and  the  products  of  its  decomposition  are  carried  away ; 
but  the  application  which  it  makes  of  such  materials  to  the  production  of  new 
organized  tissue,  and  the  various  actions  which  that  tissue  then  exerts  in  virtue 
of  its  organization,  are  not  only  incapable  of  being  explained  on  Chemical  prin- 
ciples, but  often  take  place  in  direct  antagonism  to  Chemical  forces.1 

1  It  has  seemed  advisable  to  attempt  thus  to  mark  out  the  operation  of  Chemical  Forces 
in  the  living  body,  since  the  prevalent  notions  on  this  subject  appear  to  the  Author  either 
erroneous  or  vague.  The  accumulating  evidence  of  the  purely  chemical  nature  of  many 
of  those  changes  of  composition,  which  were  formerly  set  down  as  the  results  of  "  vital  affi- 
nity," has  led  many  Chemists  to  the  idea  that  the  whole  series  of  Vital  operations  is  to  be 
explained  upon  Chemical  principles ;  and  the  notion  of  Vital  force  has  been  set  aside  as  a 
physiological  fiction,  for  which  there  is  no  longer  any  pretence.  Feeling  satisfied,  how- 
ever, that  Vital  force  has  as  certain  an  existence,  and  as  definite  a  sphere  of  operation,  as 
Chemical  Affinity,  the  Author  will  make  it  his  endeavor,  in  this  Treatise,  so  to  analyze 
the  phenomena  of  the  living  body,  as  to  trace  the  respective  limits  of  the  operation  of  each 
of  these  powers. 


ELEMENTARY  FORMS   OF    ORGANIC    STRUCTURE.  119 


CHAPTER    III. 

OF   THE    STRUCTURAL   ELEMENTS   OF   THE   HUMAN   BODY,    AND   THE 
VITAL   ACTIONS   WHICH   THEY   EXHIBIT. 

97.  IT  may  be  stated,  as  one  of  the  most  general  facts  in  Physiology,  that 
Vital  force  can  only  manifest  itself  through  that  peculiar  arrangement  of  mat- 
ter, which  is  distinguished  as  organized  structure;*  since  this  alone  affords  that 
assemblage  of  material  conditions,  which  is  required  to  concur  with  the  dynam- 
ical agency  that  is  the  active  principle  of  the  whole,  for  the  production  of  the 
phenomena  of  Life.  (See  INTRODUCTION,  p.  36.)  But  of  such  organized  struc- 
ture, there  are  a  ^reat  many  varieties,  even  within  the  single  organism  of  Man. 
Thus  it  has  been  customary  to  reckon  as  the  distinct  structural  components,  or 
Elementary  Tissues  of  which  his  fabric  is  composed,  Bones,  Teeth,  and  Carti- 
lages, which  form  its  solid  framework,  with  the  Ligaments  which  unite  these 
to  each  other,  and  the  Tendons  which  communicate  motion  to  them  from  the 
muscles ; — the  Skin  (with  its  appendages)  which  envelops  the  exterior  of  the 
body,  the  Mucous  Membranes  which  are  prolonged  from  this  into  all  the  cavi- 
ties that  are  connected  with  its  surface,  and  the  Serous  Membranes  which  line 
the  shut  sacs ; — the  Bloodvessels  and  Absorbents,  which  serve  for  the  distribu- 
tion of  the  nutritious  fluids,  and  the  Glands  which  eliminate  various  substances 
from  these ; — the  Muscles  which  communicate  motion  to  the  osseous  framework, 
or  to  the  contents  of  the  canals  and  tubules  that  convey  alimentary  and  other 
substances  through  the  system,  and  the  Nerves  which  excite  the  Muscles  to 
contraction  and  also  serve  as  the  instruments  for  the  reception  of  sensations  and 
for  the  operations  of  the  mind— and  finally,  the  Areolar  tissue  which  serves  to 
connect  together  the  preceding,  and  the  Adipose  which  is  commonly  diffused, 
more  or  less  universally,  through  this,  but  sometimes  forms  masses  of  its  own ; 
— each  of  these  having  a  structure  and  a  mode  of  vital  action  in  some  degree 
peculiar  to  itself,  and  being  hence  considered  as  possessing  distinctive  vital  en- 
dowments. In  attempting,  therefore,  to  analyze  the  varied  and  complex  pheno- 
mena which  make  up  the  physiological  history  of  Man,  there  is  an  obvious 
advantage  in  first  making  ourselves  acquainted  with  these  elementary  compo- 
nents of  his  corporeal  structure,  and  with  the  several  forms  of  vital  activity  to 
which  they  minister.  But,  although,  by  so  doing,  we  might  seem  to  have  com- 
menced with  the  very  foundations  of  Physiological  Science,  yet  such  is  not 
really  the  case ;  for  before  considering  what  are  the  peculiar  distinctions  in 
structural  arrangement  and  in  vital  properties,  which  these  tissues  severally  ex- 
hibit, we  should  inquire  what  they  all  have  in  common,  and  should  seek  to  de- 
termine whether  there  be  any  fundamental  relation  between  their  respective 
types  of  organization  and  modes  of  vital  activity,  which  is  capable  of  being  em- 
bodied in  a  general  expression.  And  this  inquiry  has  a  value  at  the  present 
time,  to  which  it  could  never  before  lay  claim ;  since,  on  the  one  hand,  the 
microscopic  examination  of  the  Elementary  Tissues,  not  only  in  their  complete 
state,  but  also  in  their  various  phases  of  development,  has  shown  that  they  have 

1  For  the  distinctive  characters  of  Organized  Structures  in  general,  see  the  Author's 
"Principles  of  Physiology,  General  and  Comparative,"  CHAP,  n.,  Am.  Ed. 


120        OF   THE    STRUCTURAL   ELEMENTS   OF   THE   HUMAN   BODY. 

far  more  of  similarity  in  intimate  structure,  as  well  as  a  closer  community  of 
origin,  than  could  have  been  even  suspected  without  such  scrutiny ;  whilst,  on 
the  other,  the  clearer  apprehension  to  which  we  have  been  led  by  the  progress 
of  Physical  Philosophy,1  in  regard  to  the  relations  of  different  modes  of  Dynami- 
cal agency,  seems  to  render  it  possible  to  attain  to  a  far  more  definite  and  compre- 
hensive view  than  was  previously  within  our  reach,  in  regard  to  the  nature  of  Vital 
Force,  and  the  conditions  of  its  operation.  Of  the  existence  of  this  force,  we 
have  just  as  much  evidence  in  the  phenomena  exhibited  by  living  beings,  as  we 
have  of  the  force  of  Gravitation  in  determining  the  movements  of  the  heavenly 
bodies,  or  of  that  of  Chemical  Affinity  in  producing  changes  of  combination 
among  the  elements  of  our  own  planet.  But  the  peculiar  complexity  of  the 
circumstances  under  which  it  operates,  and  the  co-operation  of  Chemical  and 
Physical  agencies  in  many  of  the  phenomena  which  essentially  depend  upon  it, 
frequently  obstruct  the  recognition  of  its  acts,  and  constitute  an  additional  rea- 
son for  studying  these  under  their  simplest  forms. 

1.    Of  the  Elementary  Forms  of  Organic  Structure,  and  their  Modes  of  Vital 

Activity. 

98.  All  the  Elementary  Tissues  seem  reducible,  by  Microscopic  analysis,  to 
three  primitive  forms ;— namely,  Cells,  Fibres,  and  Membranes.     Of  these  it 
is  obvious  that  Cells  are  the  most  essential  j  since  in  the  entire  Vegetable  king- 
dom, as  well  as  in  the  lowest  tribes  of  Animals,  the  whole  fabric  is  composed  of 
cells  and  their  derivatives ;  and  there  is  a  period  in  the  history  of  even  the 
Human  organism,  when  neither  of  the  other  elements  exists.     We  shall  find, 
moreover,  that  it  is  by  cells  and  their  derivatives,  that  all  the  proper  vital 
actions  of  the  body  are  performed.     To  these  elements,  however,  Fibres?  are 
added  in  the  bodies  of  the  higher  animals ;  for  the  sole  purpose,  apparently,  of 
conferring  upon  their  parts  that  freedom  of  movement  which  is  essential  to  the 
conditions  of  Animal  existence.     There  is  every  reason  to  believe,  that  their 
function  is  purely  physical ;  being  nothing  else  than  the  resistance  to  tension 
(with  or  without  a  certain  degree  of  elasticity),  of  which  advantage  is  taken  in 
two  principal  modes;  such  fibres  being  used  to  bind  together  separate  parts  that 
are  to  have  a  certain  range  of  motion  one  upon  the  other,  and  also  to  communi- 
cate and  apply  mechanical  power  generated  at  some  other  and  (it  may  be)  dis- 
tant point.     The   simple  homogeneous  Membrane,  also,  which  is  known  as 
"primary"  or  " basement-membrane,"  must  be  considered  as  one  of  the  less 
essential  among  the  fundamental  constituents  of  the  Human  organism ;  though 
its  office  is  still  of  great  importance.     As  regards  the  vital  functions,  simple 
membrane  may  be  considered  as  entirely  passive ;  but  it  serves  the  very  im- 
portant physical  purpose  of  limiting  and  bounding  the  tissues  of  various  organs, 
and  of  separating  the  various  collections  of  fluid  within  the  body,  in  such  a 
manner  as  to  prevent  their   too  ready  admixture,  whilst  admitting  a  certain 
amount  of  transudation  from  one  to  the  other. — We  shall  now  consider  each  of 
these  Elements  in  more  detail. 

99.  Of  Cells,  and  Cell-Life. — The  Cells  which  are  thus  to  be  regarded  as 
the  fundamental  components  of  the  Animal  body,  differ  in  no  important  par- 
ticular of  structure  or  composition,  from  those  of  which  the  Vegetable  fabric  is 
made  up ;  and  their  endowments  also  may  be  shown  to  be  essentially  similar, 

See  especially  Prof.  Grove's  Treatise  on  "The  Correlation  of  the  Physical  Forces." 
2  This  term  is  here  used  in  the  strict  sense,  as  applicable  to  the  solid  and  simple  fibres 
of  which  Ligaments,  Tendons,  &c.  are  made  up,  and  not  to  the  (so-called)  Muscular  and 
Nervous  fibres,  which,  as  will  hereafter  appear,  are  really  tubes  consisting  of  elongated  or 
coalesced  cells. 


OF   CELLS   AND   CELL-LIFE.  121 

although  by  no  means  identical.1 — The  fully-formed  cell  (Fig.  4)  is  a  membran- 
ous bag  or  vesicle,  enclosing  a  cavity,  which  is  occupied  by  some  kind  of  liquid 
or  solid  substance.     Its  typical  form  may  be  con- 
sidered as  globular  or  spheroidal;  but  this  is  com-  Fig.  4. 
paratively  seldom  exhibited,  except  in  newly-gene- 
rated cells  ;  for  it  is  usually  more  or  less  altered 
subsequently,   by  forces  operating  either  within 
the  cell  or  externally  to  it.     Thus  the  cells  of 
adipose  tissue,  which  are  usually  spheroidal  when 
lying  separately  in  the  midst  of  areolar  tissue 
(Fig.  48),  become  polyhedral  by  mutual  pressure 
when  compacted  into  a  mass  (Fig.  49).     Many 


kinds  of  cells  have  the  form  of  flattened  disks  ;       Cells  from  chorda  dorgalia  of  Lam. 
these  being  sometimes  regularly  circular  or  ellip-     prey :  a,  a,  their  nuclei, 
tical,  as  the  red  corpuscles  of  the  blood  (Figs.  11 

and  12),  sometimes  polygonal,  as  the  pigment-cells  of  the  choroid  coat  (Fig.  39), 
and  some  varieties  of  the  pavement-epithelium  (Fig.  13) ;  but  frequently  of 
irregular  outline,  as  is  more  commonly  the  case  with  the  pavement-epithelium 
(Fig.  24)  and  with  the  cells  composing  the  parenchyma  of  the  liver  (Fig.  157,  B). 
This  flattening  proceeds  so  far  in  the  cells  of  the  epidermis,  as  to  render  them 
mere  scales  (Fig.  36,  a).  On  the  other  hand,  the  originally-spheroidal  cells  may 
become  elongated,  instead  of  depressed ;  and  may  then  assume  either  a  very 
regular  prismatic  form  with  flattened  polygonal  extremities,  as  in  some  varieties 
of  cylinder-epithelium,  but  especially  in  the  enamel  of  teeth  (Fig.  77);  or  these 
elongated  cells  may  be  more  or  less  cylindrical  with  pointed  extremities,  thus 
becoming  fusiform  or  spindle-shaped,  as  is  well  shown  in  the  cells  forming  the 
shaft  of  the  hair,  but  still  better  in  those  of  which  the  "  smooth"  or  "  non- 
striated^  muscular  fibre  is  composed  (Fig.  99).  One  of  the  most  curious 
examples  of  change  of  form,  however,  is  presented  by  those  cells,  which,  while 
not  departing  from  the  spheroidal  type,  send  out  caudate  processes ;  and  these, 
when  they  issue  from  the  whole  circumference  of  the  cell,  give  to  it  a  stellate 
character.  Both  caudate  and  stellate  cells  are  found  in  the  vesicular  substance 
of  the  nervous  tissue  (Fig.  107),  and  in  the  pigment-cells  of  the  lower  animals 
(Fig.  87,  3,  3);  and  it  is  probable  that  the  "  lacunae"  and  "canaliculi"  of  bone 
(Fig.  62)  are  stellate  cells,  and  that  it  is  also  by  the  inosculation  of  the  peri- 
pheral extensions  of  such  cells,  that  'the  ultimate  ramifications  of  capillary  blood- 
vessels, absorbents,  and  nerves,  are  at  first  generated  (Fig.  89). — The  size  of 
cells  is  not  less  variable  than  their  forms.  Thus  even  in  the  Human  body,  we 
find  them  ranging  from  l-300th  of  an  inch,  which  is  the  diameter  of  many  fat- 
cells  and  nerve-vesicles,  to  about  l-3200th  of  an  inch,  which  is  the  average 
diameter  of  the  red  blood-disks,  and  thence  to  as  little  as  l-10,000th  or  even 
l-15,000th  of  an  inch,  which  is  the  ordinary  diameter  of  the  fibrillse  of  the 
"  striated"  muscle,  each  of  which,  as  will  be  shown  hereafter,  is  a  linear  series 
of  very  minute  cells  (Fig.  95). — Either  lying  freely  within  the  cavity  of  the 
cell,  or,  as  more  commonly  happens,  attached  to  some  part  of  its  walls,  we 
usually  find  a  body  of  a  somewhat  granular  appearance,  which  is  called  a  nucleus 
(Fig.  4,  a).  And  thus,  in  examining  into  the  structure  and  endowments  of 
cells,  we  have  to  consider  (1)  the  cell-wall,  (2)  the  cell-contents,  and  (3)  the 
nucleus. 

100.  The  Cell-wall,  in  its  primitive  state,  is  an  apparently  structureless  or 
homogeneous  membrane  of  extreme  tenuity;  resembling,  in  fact,  the  base- 
ment-membrane to  be  hereafter  described.  In  composition  it  agrees  uniformly 
(so  far  as  is  yet  known)  with  the  protein-compounds;  and  it  is  only  when  ad- 

1  See  "Princ.  of  Gen.  and  Comp.  Phys.,"  CHAP,  iv.,  Am.  Ed. 


122         OP   THE   STRUCTURAL   ELEMENTS   OF   THE   HUMAN   BODY. 

ventitious  deposits  have  been  made  upon  its  interior,  from  the  peculiar  contents 
of  the  cell — as  in  the  case  of  the  deposit  of  horny  matter  within  the  cells  of 
the  epidermic  tissues — that  its  character  seems  altered.  This  uniformity  in 
the  composition  of  the  cell-wall  is  indicated,  independently  of  other  consider- 
ations, by  the  uniform  action  of  acetic  acid  upon  it;  for  except  in  the  cases  in 
which  the  original  cell-walls  are  thickened  by  secondary  deposit,  this  reagent 
renders  them  so  transparent,  that  they  become  for  the  time  almost  invisible, 
though  brought  into  view  again  on  the  addition  of  potash.  It  is  one  of  the 
most  remarkable  peculiarities  of  this  membrane,  that  whilst  it  keeps  together 
the  liquid  contents  of  the  cell,  and  can  afford  resistance  to  any  ordinary  mechani- 
cal force  tending  to  their  expulsion,  it  may  still  permit  the  most  ready  transu- 
dation  of  fluids,  although  not  the  slightest  trace  of  pores  for  their  passage 
through  it  can  be  seen  with  the  highest  magnifying  powers.  And  thus,  in  the 
ordinary  current  of  nutrition,  fluids  may  pass  from  cell  to  cell,  apparently  by 
endosmotic  action,  with  considerable  rapidity,  notwithstanding  the  presence  of 
the  intervening  septa.  There  is  no  evidence  that  this  membrane  possesses  any 
distinctly  vital  property;  and  its  function  appears  essentially  to  consist  in  the 
limitation  of  the  cell-contents,  which  are  drawn  together  by  other  agency.  For 
when  we  examine  into  the  history  of  cytogenesis  or  cell-formation,  we  shall  find 
that  when  cells  originate  de  novo,  the  cell-membrane  is  generated  at  a  compara- 
tively late  stage,  not  making  its  appearance  until  the  other  components  are 
already  in  existence  (§  106). 

101.  The  Cell-contents  are  as  varied  in  their  composition,  as  the  cell-walls  are 
uniform.  In  the  first  place,  they  may  be  either  solid  or  liquid.  Of  the  solid, 
we  have  examples  in  the  prismatic  cells  of  the  enamel  of  teeth  (Fig.  77),  which 
are  completely  filled  with  mineral  matter  in  a  state  of  crystalline  aggregation, 
just  as  are  the  prismatic  cells  which  form  the  external  layer  of  many  bivalve 
shells.1  So,  again,  the  contents  of  the  cells  which  constitute  the  horny  layer  of 
the  epidermis  and  the  substance  of  the  nails  (Fig.  40),  become  solid  by  the 
desiccation  of  the  fluid  in  which  the  horny  matter  seems  to  have  been  originally 
dissolved.  It  is  obvious,  however,  that  no  vital  action  can  go  on,  in  cells  whose 
contents  are  of  such  a  character ;  and  we  accordingly  find  that  the  tissues  thus 
consolidated  are  completely  thrown  out  of  the  current  of  change,  and  that  their 
functions  are  purely  physical — that  of  the  Epidermis  and  its  horny  appendages, 
as  well  as  of  Shell,  being  simply  protective,  and  that  of  the  Enamel  of  teeth 
being  to  resist  pressure.  The  liquid  cell-contents  are  extremely  various;  and  it 
is,  in  fact,  in  their  diversity,  that  the  peculiarity  of  many  tissues  consists.  Thus, 
as  we  shall  hereafter  see,  all  the  glands  are  formed  upon  a  plan  essentially  the 
same;  and  their  different  endowments  are  entirely  due  to  the  diverse  properties 
of  the  cells  of  which  they  are  essentially  composed,  one  set  filling  themselves 
with  the  components  of  bile  (Fig.  30),  another  with  those  of  milk,  another  with 
sebaceous  matter,  whilst  within  another  set  are  generated  the  moving  particles 
characteristic  of  the  seminal  secretion  (Plate  I.  Fig.  3).  Again,  we  shall  find 
one  set  of  cells  drawing  fatty  matter  into  their  interior  from  the  contents  of 
the  alimentary  canal  (Fig.  135),  whilst  another  set,  eliminating  a  similar  sub- 
stance from  the  blood,  stores  it  up  as  a  part  of  the  bodily  fabric  (Fig.  48). 
And  the  color  which  is  characteristic  of  particular  parts,  as,  for  instance,  the 
lining  of  the  choroid  coat  of  the  eye,  the  mammary  areola,  the  hair,  and  the 
entire  epidermis  of  the  dark  races  of  mankind,  the  red  corpuscles  of  the  blood, 
and  the  vesicles  of  nervous  matter,  is  due  to  the  presence  of  pigmentary  matter, 
either  of  a  deep  black,  or  of  some  lighter  hue,  which  forms  either  a  part  or  the 
whole  of  the  contents  of  particular  cells.  These  several  sets  of  cells  cannot  be 
formed,  therefore,  unless  that  pabulum  be  supplied  to  them  which  they  require, 

1  See  "Prin.  of  Gen.  and  Comp.  Phys.,"  §  197,  Am.  Ed. 


OF   CELLS   AND   CELL-LIFE.  123 

not  merely  for  the  generation  of  their  cell-wall,  but  also  for  the  filling  of  their 
cavity  with  its  characteristic  contents ;  and  we  shall  find  that  in  some  instances 
this  pabulum  appears  itself  to  contain  these  peculiar  substances  already  formed, 
whilst  in  others  the  cell  seems  to  exercise  a  certain  converting  power,  by  which 
it  produces  them  from  some  other  compounds.  Not  unfrequently,  the  contents 
of  the  cells  include  a  number  of  minute  molecules;  and  these  exhibit  an  active 
movement  within  the  cell,  especially  when  water  is  added,  so  as  to  dilute  the 
fluid  in  which  they  are  suspended.  This  movement,  which  is  well  seen  in  the 
interior  of  the  colorless  corpuscles  of  the  blood,  of  the  nerve-vesicles,  of  pus 
and  mucus-corpuscles,  of  pigment-cells,  and  occasionally  in  cells  of  other  kinds, 
is  not  to  be  regarded  as  having  any  dependence  on  vital  forces ;  for  it  is  nothing 
else  than  the  "  molecular  movement/7  which  (as  long  since  shown  by  Mr.  Rob- 
ert Brown)  is  exhibited  by  almost  any  very  finely-divided  particles  that  are 
freely  suspended  in  liquids.1 

102.  The  nuclei  of  cells  present  numerous  varieties  of  structure  and  aspect. 
In  their  simplest  condition,  they  seem  to  be  nothing  else  than  assemblages  of 
minute  particles,  sometimes  of  molecular  minuteness,  in  other  instances  large, 
well-defined  granules;  and  among  these  may  usually  be  distinguished  some  that 
are  of  an  oleaginous  character.  In  other  cases,  again,  these  assemblages  of 
granules  appear  to  have  a  distinct  investment  of  their  own,  which  separates  them 
from  the  general  cavity  of  the  cell;  this  is  most  distinctly  seen  in  pigment- 
cells  and  epidermic  cells.  At  or  near  the  centre  of  the  nucleus,  one  or  more 
corpuscles  are  frequently  seen,  very  distinct  from  its  general  mass,  which  are 
termed  nucleoli  (Fig.  24,  c);  and  these  appear  in  many  instances  to  have  the 
character  of  minute  vesicles.  It  is  probable,  however,  that  the  term  "  nucle- 
olus"  has  been  attached  to  bodies  which  are  really  very  different  from  each 
other,  both  structurally  and  functionally;  and  there  is  yet  much  to  be  learned 
on  the  subject.  The  nucleus,  as  already  stated,  is  usually  found  attached  to  the 
inner  wall  of  the  cell,  and  sometimes  even  appears  to  be  imbedded  in  its  sub- 
stance ;  but  it  is  occasionally  observed  to  lie  freely  in  the  cavity.  The  form  of 
the  nucleus  is  for  the  most  part  nearly  circular,  and  it  may  be  usually  observed 
to  continue  so,  even  when  the  form  of  the  cell  has  undergone  its  most  remark- 
able alterations,  e.  g.  becoming  fusiform  or  stellate  ;3  but  a  very  peculiar  excep- 
tion is  presented  by  the  nuclei  of  the  "  smooth"  muscular  fibre-cells,  which  are 
staff-shaped  (Fig.  100,  c);  this  character  serving  to  distinguish  these  cells  from 
others  which  closely  resemble  them  in  form,  but  which  do  not  possess  their 
peculiar  vital  endowments.  The  size  of  the  nuclei  is  more  constant  than  that 
of  the  cells  in  which  they  are  found ;  their  usual  diameter  being  from  l-4000th 
to  l-6000th  of  an  inch.  Hence  the  proportion  of  the  cell  which  the  nucleus 
occupies  is  extremely  variable ;  for  the  whole  cell-cavity  is  sometimes  nearly 
filled  by  it,  especially  in  young  cells,  so  that  it  is  difficult  to  make  out  the  pre- 
sence of  a  distinct  cell- wall,  unless  by  adding  water  or  acetic  acid  which  raises  up 
the  latter ;  whilst  in  other  instances,  especially  when  the  cell  is  fully  formed, 
the  nucleus  is  comparatively  small,  being  only  from  one-fourth  to  one-tenth  of 
the  diameter  of  the  cell.  The  former  condition  is  well  seen  in  the  chyle  and 
lymph-corpuscles;  the  latter  in  the  pavement  epithelium-cells  (Fig.  24).  That 
the  composition  of  the  nucleus  is  in  some  respects  different  from  that  of  the  cell- 
wall,  is  shown  by  the  fact  that  the  contact  of  acetic  acid  neither  dissolves  it  nor 

1  One  of  the  most  convenient  methods  of  exhibiting  this  movement  is  to  rub  up  a  little 
Gamboge  in  water;  for  the  resinous  particles  of  this  substance,  being  suspended  by  the 
gummy,  will  continue  in  motion  for  any  length  of  time,  even  when  completely  secluded 
from  the  air,  so  that  evaporation  of  the  liquid  can  have  nothing  to  do  with  it. 

2  A  stellate  nucleus  is  normally  found  in  the  cartilage-corpuscles  of  Cephalopoda,  and 
abnormally  in  some  cartilaginous  tumors  in  Man.     See  Mr.  Paget's  "Lectures  on  Tumors," 
"Medical  Gazette,"  Aug.  8,  1851. 


124         OF   THE    STRUCTURAL   ELEMENTS   OP   THE    HUMAN   BODY. 

renders  it  transparent,  but  on  the  contrary  brings  it  into  greater  distinctness 
(partly  by  rendering  the  cell-wall  transparent)  ;  it  is  not  yet  known,  however, 
what  is  the  precise  nature  of  its  component  substance.  It  seems  to  be  the 
general  fact,  that  every  Animal  cell  possesses  a  nucleus  at  some  period  or  other 
of  its  life;  and  this  nucleus  seems  to  be  usually  persistent  (as  it  is  capable  of 
being  brought  into  view  by  reagents,  when  it  is  not  otherwise  apparent),  so  long 
as  the  cell  itself  is  undergoing  developmental  changes.  But  in  the  state  of 
complete  development,  the  nucleus  sometimes  disappears  ;  thus  it  is  normally 
absent  in  the  red  corpuscles  of  the  blood  of  Mammals,  and  not  unfrequently  in 
fat-cells  ;  and  it  is  frequently  seen  to  present  a  shrunken  and  wasted  appearance 
in  the  cells  of  tissues  which  are  undergoing  degeneration.  It  will  be  presently 
shown,  that  there  is  strong  reason  to  regard  the  nucleus  as  the  chief  agent  in 
the  vital  operations  of  the  cell  ;  seeing  that  it  can  exercise  its  functions  even 
without  the  development  of  a  cell-wall  to  enclose  the  substances  which  it  draws 
around  it,  and  on  which  it  exercises  its  peculiar  powers  (§  117).  Where  two 
or  more  nuclei  are  seen  in  a  single  cell  (Fig.  8),  they  may  be  regarded  as  origi- 
nating in  the  subdivision  of  the  primordial  single  nucleus,  and  as  indicating  the 
approaching  subdivision  of  tne  cell  itself,  or  the  formation  of  a  young  cell  with- 
in it. 

103.  The  history  of  the  Animal  cell,  in  its  simplest  form,  is  precisely  that 
of  a  Vegetable  cell  of  the  lowest  kind.  -  Every  cell  lives  for  itself,  and  by  itself, 
like  each  of  the  solitary  cells  of  the  humblest  Protophytes  ;  and  if  the  neces- 
sary conditions  be  furnished  (these  being  essentially  a  due  supply  of  nutriment, 
and  a  proper  temperature),  it  may  continue  to  live  and  to  grow,  and  may  go 
through  all  the  phases  of  its  development,  quite  independently  of  the  organism 
of  which  it  originally  formed  part.  Of  this  we  have  numerous  examples  in  the 
artificial  implantation  of  parts  of  one  body  upon  or  within  another  ;  the  graft 
uniting  itself  with  its  new  stock,  and  continuing  to  grow  after  its  own  fashion 
at  the  expense  of  the  nourishment  thence  derived.  But  a  still  more  remark- 
able example  is  normally  and  constantly  presented  by  the  spermatic  cells  of 
certain  animals,  such  as  the  Decapod  Crustacea1  and  certain  Nematoid  Entozoa  ;3 
which  are  cast  forth  from  the  organs  of  the  male  in  which  they  were  generated, 
and  are  transferred  into  the  body  of  the  female,  when  as  yet  they  are  in  a  com- 
paratively early  stage  of  their  own  development;  the  spermatozoa  being  not 
yet  formed  within  them,  but  being  produced  during  the  subsequent  life  of  the 
cells,  which  apparently  goes  on  as  favorably  within  the  generative  passages  of 
the  female,  as  it  would  have  done  within  the  organs  in  which  the  spermatic  cells 
were  at  first  formed,  the  requisite  conditions  being  duly  supplied.3  All  the 
component  cells  of  any  one  organism  may  be  considered  as  the  descendants  of 
the  primordial  cell  in  which  it  originated;  but  the  methods  of  their  production 
are  by  no  means  the  same  in  every  instance,  an  end  essentially  the  same  being 
brought  about  by  means  which  appear  (at  least)  to  be  very  different.  The 
various  modes  of  cell-development  may,  however,  be  reduced  to  two  principal 
forms;  —  that,  namely,  in  which  the  new  cells  arise  from  or  within  pre-existing 
cells,  being  produced  by  the  subdivision  either  of  the  cells  themselves,  or  of 
their  nuclei,  which  is  termed  endogenous  development;  —  and  that  in  which  they 
originate  in  germs  developed  de  novo  in  the  midst  of  an  organizable  "  blastema," 
which  has  been  prepared  by  a  previous  exercise  of  vital  force,  and  which  still 
requires  the  continued  operation  of  that  force  ab  extra  for  its  due  organization 
(§  29).  Each  of  these  modes  of  cytogenesis,  or  cell-development,  will  now  be 
separately  considered. 


'  Mr.  H.  D.  S.  Goodsir,  in  "Anatomical  and  Pathological  Observations,"  p.  39. 
•  Dr.  Nelson,  "Proceedings  of  the  Royal  Society,"  J 
3  For  an  application  of  this  curious  fact  to  the  possib 
protracted  gestation  in  the  Human  subject,  see  CHAP.  xix. 


•  Dr.  Nelson,  "Proceedings  of  the  Royal  Society,"  June  19,  1851. 

3  For  an  application  of  this  curious  fact  to  the  possible  explanation  of  certain  cases  of 


OF   CELLS   AND   CELL-LIFE. 


125 


104.  The  multiplication  of  cells  by  duplicative  subdivision,  which  is  the  most 
common  form  of  cytogenesis  in  the  Vegetable  kingdom,  and  which  is  particular- 
ly well  seen  in  the  simplest  Cellular  Plants 
(Fig.  5),  is  observed  to  take  place  also 
within  the  Animal  body,  after  a  manner 
essentially  the  same,  in  most  cases  in  which 
new  parts  are  being  developed  in  continuity 
with  the  old.  The  most  characteristic  ex- 
ample of  it  is  seen  in  the  early  Embryo ; 
which,  at  first  consisting  of  but  a  single 
cell,  has  its  number  of  cells  augmented  by 
such  duplication,  to  2,  4,  8,  16,  32,  64,  &c. 
(Fig.  6.)  The  same  process  may  also  be 
watched  through  the  whole  of  life  in  Carti- 
lage ;  and  it  is  one  of  the  means  by  which 
the  Red  Corpuscles  of  the  blood  are  multi- 
plied in  an  early  stage  of  their  development 
(§  149).  The  commencement  of  this  pro- 
cess in  the  Vegetable  cell  is  indicated  by 
its  elongation,  and  by  a  slight  hour-glass 
constriction  (Fig.  5,  6),  which  seems  due 
to  the  tendency  of  the  contents  of  the  cell 
to  separate  into  two  halves ;  and  between 
these  a  division  is  subsequently  formed 
(GJ  d)  by  the  gradual  infolding  of  the 
"  primordial  utricle,"  or  inner  cell-wall,  which  is  the  true  representative  of  the 
wall  of  the  Animal  cell.1  Where  a  distinct  nucleus  exists,  however — as  is  the 

Fig.  6. 


Hcematococcus  binalis,  in  various  stages  of  de- 
velopment; a,  a,  simple  rounded  cells;  6,  elon- 
gated cell,  the  endochrome  preparing  to  divide ; 

c,  c,  cells  in  which  the  division  has  taken  place; 

d,  large  parent  cell,  in  which  the  process  has  been 
repeated  a  second  time,  so  as  to  form  a  cluster 
of  four  secondary  cells,  such  as  is  often  seen  in 
Cartilage. 


Multiplication  of  cells  by  binary  subdivision;  A,  B,  c,  D,  early  stages  of  the  process,  from  ovum  of  Ascaris 
dentata;  E,  p,  G,  H,  more  advanced  stages,  from  ovum  of  Cucullanus  degans, 

case  in  most  Animal  cells — the  process  of  subdivision  seems  frequently  to  com- 
mence in  it ;  for  before  any  distinct  inflection  of  the  cell-wall  can  be  perceived, 
the  nucleus  may  be  seen  to  elongate,  and  to  show  a  tendency  to  subdivision  into 
two  equal  parts.  Each  of  these,  wKen  completely  separated,  draws  round  it  a 
portion  of  the  contents  of  the  cell ;  so  that  the  cell-wall,  which  at  first  exhibits 


1  See  "Prin.  of  Phys.,  Gen.  and  Comp.,"  pp.  91,  92,  Am.  Ed. 


126 


OF   THE    STRUCTURAL   ELEMENTS    OF    THE    HUMAN   BODY. 


merely  a  sort  of  hour-glass  contraction,  is  at  last  inflected  so  far  as  to  constitute 
a  complete  partition  between  the  two  halves  of  the  original  cell;  and  these 
henceforth  become  two  independent  cells,  which  may  go  through  the  same  pro- 
cess in  their  turn  (Fig.  7,  A — D).  The  repetition  of  this  operation  may  take 
place  either  in  the  same  or  in  the  contrary  direction,  so  as  to  produce  four  cells, 
either  linearly  arranged  (E,  F,  G),  or  clustered  together  (H)  ;  and  this  dupli- 
cation may  go  on  upon  the  same  plan,  until  a  large  mass  has  been  produced  by 
the  subdivision  of  a  single  original  cell.  In  ordinary  Cartilage,1  it  is  most  com- 
mon to  see  the  cells  forming  clusters  (Fig.  41) ;  but  in  Cartilage  which  is  being 
prepared  for  ossification,  we  see  long  lines  of  cells,  which  have  been  obviously 
produced  by  the  first  of  these  methods  of  multiplication  (Figs.  65,  66). 

Fig.  7. 

A  B  C  D 


Multiplication  of  Cartilage-cells  by  duplication:  A,  original  cell;  B,  the  same  beginning  to  divide;  c,  the 
same  showing  complete  division  of  the  nucleus ;  D,  the  same  with  the  halves  of  the  nucleus  separated,  and  the 
cavity  of  the  cell  subdivided;  E,  continuation  of  the  same  process,  with  cleavage  in  contrary  direction,  to  form 
a  cluster  of  four  cells ;  F,  G,  H,  production  of  a  longitudinal  series  of  cells,  by  continuation  of  cleavage  in  the 
same  direction. 

105.  Not  unfrequently,  however,  the  multiplication  of  cells  takes  place,  not 
so  much  by  the  subdivision  of  the  pre-existing  cell,  as  by  the  development  of 
new  cells  in  its  interior ;  these  appear  to  take  their  origin  in  the  nucleus,  which 
subdivides  into  two  or  more  portions,  each  of  them  drawing  a  portion  of  the  con- 
tents of  the  parent-cell  towards  itself,  and  becoming  converted  into  a  cell  by  the 
development  of  a  cell-wall  around  this ;  and  they  gradually  increase  in  dimen- 
sions, until  they  come  to  occupy  the  entire  cavity  of  the  parent-cell,  and  may  so 
distend  its  wall,  by  their  further  enlargement,  that  it  can  no  longer  be  distin- 
guished. Of  this  method  of  cell-formation,  also,  we  have  examples  in  cartilage, 
especially  in  its  early  stage  of  development,  when  its  growth  is  rapid  (Fig.  8) ; 
but  we  there  seldom  see  more  than  three  or  four  cells  thus  generated  within 
a  parent-cell  at  any  one  time.  It  is  in  structures  of  more  rapid  growth,  such 

1  It  is  thought  by  Dr.  Leidy,  who  has  carefully  studied  this  process  in  Cartilage  (see 
his  valuable  paper  "On  the  Intimate  Structure  and  History  of  Articular  Cartilages,"  in 
the  "Amer.  Journ.  of  Med.  Sci.,"  April,  1849),  that  the  direction  of  the  subdivision  is 
determined  by  that  in  which  there  is  least  resistance  to  the  extension  of  the  group  of  cells ; 
but  such  can  scarcely  be  the  case  in  regard  to  the  embryonic  mass,  the  cells  of  which,  if 
this  were  the  sole  determining  influence,  would  continue  to  multiply  on  a  uniform  plan ; 
instead  of  which,  as  soon  as  they  have  arrived  at  a  certain  degree  of  minuteness  of  sub- 
division, a  diversity  of  arrangement  begins  to  show  itself  in  the  component  parts  of  what 
was  previously  a  homogeneous  assemblage. 


OF   CELLS  AND   CELL-LIFE. 


127 


as  granulations/  and  especially  in  cells 
of  a  cancerous  or  malignant  character, 
whose  speedy  development  and  no  less 
speedy  degeneration  are  among  their 
most  distinguishing  features,  that  we 
most  frequently  witness  the  subdivi- 
sion of  the  nucleus  into  a  considerable 
number  of  parts,  and  the  development 
of  numerous  cells  at  one  time  within 
the  cavity  of  each  parent-cell  (Fig.  9). 
The  same  method  may  often  be  reco'g- 
nized,  however,  in  the  development  of 
cells  within  Glandular  follicles;  for 
where  each  follicle  is  a  single  parent- 
cell,  and  its  nucleus  remains  persistent 
as  a  "  germinal  centre,"  subsequently 
to  its  becoming  a  follicle  by  the  rup- 
ture or  thinning  away  of  a  part  of  its 
cell-wall,  it  appears  to  be  by  the  con- 
tinual sprouting  of  new  cells  from  this 
nucleus,  that  the  materials  of  the  secre- 
tion are  eliminated  from  the  blood 
(Fig.  30). — As  a  general  rule,  how- 
ever, it  may  be  remarked,  that  the 
production  of  a  large  number  of  cells 
within  a  single  parent-cell  only  takes 
place  when  this  new  brood  is  not  to 
form  a  permanent  part  of  the  organism, 
or  to  be  itself  the  originator  of  a  sub- 
sequent growth.  It  would  seem,  in- 
deed, as  if  this  rapid  method  of  multi- 
plication occasioned  an  exhaustion  of 
vital  force ;  so  that  the  cells  thus  gene- 
rated are  incapacitated  for  any  other 
purpose ;  whilst  the  comparatively  slow 
method  of  duplicative  subdivision  may 
be  repeated,  time  after  time,  to  an  ex- 
tent to  which  it  is  impossible  to  assign 
a  limit,  each  pair  of  cells  thus  pro- 
duced having  an  equal  capacity  with 
its  progenitors  for  going  through  that 
process. 

106.  There  are  cases,  however,  in 
which  cells  are  developed,  without  any 
direct  connection  with  pre-existing 
cells,  in  the  midst  of  a  blastema  or  for- 
mative fluid  poured  out  from  the  blood. 
Still,  it  is  uncertain  to  what  extent  this 
is  to  be  considered  as  one  of  the  ordi- 
nary modes  in  which  the  elements  of 


Fig.  8. 


L 


Section  of  branchial  Cartilage  of  Tadpole  of  Rana, 
paradoxa :  a,  fe,  c,  intercellular  substance,  with  which 
the  walls  of  the  parent-cells  are  incorporated ;  d,  single 
nucleus;  e,  nucleus  dividing  into  two;  df,  e',  two 
nuclei  in  one  cell,  formed  by  division  of  single  nucleus ; 
/.  secondary  cell,  forming  around  nucleus  g ;  h,  two 
nuclei  within  single  secondary  cell ;  t,  three  secondary 
cells,  within  one  primary  cell. 

Fig.  9. 


Endogenous  cell-growth  in  cells  of  a  Meliceritous 
Tumor:  a,  cells  presenting  nuclei  in  various  stages 
of  development  into  a  new  brood;  6,  parent-cell, 
completely  filled  with  a  new  brood  of  young  cells, 
which  have  originated  from  vthe  granules  of  the 
nucleus. 


1  It  is  stated  by  Mr.  Paget  ("  Lectures  on  the  Processes  of  Repair  and  Reproduction  after 
Injuries,"  in  the  "  Medical  Gazette,"  1849)  that  in  granulations  there  are  often  to  be  found 
large  compound  cells  of  oval  form,  and  as  much  as  l-250th  of  an  inch  in  diameter,  containing 
eight,  ten,  or  more  nuclei,  which  have  been  derived  by  subdivision  from  the  nucleus  of  the 
simple  cell,  and  which  are  probably  destined  to  be  the  nuclei  of  as  many  separate  cells. 


128          OF   THE   STRUCTURAL  ELEMENTS    OF   THE    HUMAN   BODY. 

the  tissues  are  produced  and  increased ;  for  it  has  been  hitherto  chiefly  observed 
in  cases  in  which  a  plastic  exudation  has  been  poured  out  for  reparative  purposes, 
or  in  which  a  structure  of  an  abnormal  character  is  being  generated.  The  first  step 
in  the  process  usually  appears  to  be  the  aggregation  of  some  of  the  minute  mole- 
cules which  the  fluid  or  semi-solid  blastema  contains,  so  that  they  form  little 
rounded  masses,  or  nuclei,  from  which  the  new  cells  originate.  The  mode  in 
which  the  cell-wall  is  formed  does  not  appear  to  be  by  any  means  constant. 
Sometimes  it  seems  to  rise  and  separate  itself  from  the  nucleus  itself,  as  if  it 
were  formed  by  the  melting  together  of  molecules  precipitated  upon  or  attracted 
to  the  nucleus ;  but  more  frequently  it  appears  to  be  generated  by  the  expansion 
of  the  wall  of  the  nucleus  itself;  in  either  case,  however,  commencing  to  enlarge 
and  separate  itself  from  the  nucleus  by  the  endosmosis  or  assimilation  of  fluid 
from  the  surrounding  blastema.1  But  there  are  other  cases  in  which  the  nuclear 
particles  appear  to  draw  around  them  certain  components  of  the  substance  in 
which  they  lie,  before  any  cell-wall  can  be  discerned,  this  being  subsequently 
generated  around  this  collection,  which  then  constitutes  the  contents  of  the 
newly-formed  cell.  This  first-formed  nucleus  may  be  persistent,  and  may  take 
a  part  in  the  subsequent  vital  actions  of  the  cell,  of  whatever  kind  these  may 
be ;  or  it  may  be  superseded  by  a  second  nucleus,  which  subsequently  makes  its 
appearance  in  some  other  part  of  the  cell-wall. — It  seems  probable  that  the  first 
formation  of  the  chyle  and  lymph-corpuscles,  which  subsequently  develop  them- 
selves into  blood-corpuscles,  takes  place  from  free  nuclei ;  and  it  has  been  main- 
tained by  some  that  the  epidermis  and  epithelium  are  likewise  formed  in  the 
same  manner; — both  these  views,  however,  require  confirmation. 

107.  Another  mode  of  Cytogenesis  must  be  mentioned  as  of  occasional  occur- 
rence ;  namely,  the  expansion  of  a  single  apparently  homogeneous  granule  into 
a  cell,  without  the  previous  formation  of  any  perceptible  nucleus;  a  distinction 
first  showing  itself  between  the  exterior  portion  of  the  granule,  which  becomes 
the  cell-wall,  and  the  interior  which  seems  to  melt  down  to  form  the  first  cell- 
contents;  and  the  former  extending  itself,  as  the  latter  augment  by  imbibition 
from  the  surrounding  fluid.  It  is  on  this  plan  that  the  development  of  the 
"  zoospores"  of  many  of  the  Algae  seems  frequently  to  take  place  ;a  for  these,  at 
the  time  of  their  emission,  can  frequently  not  be  considered  as  anything  else 
than  "  granules."  And  the  first  development  of  blood-corpuscles  in  the  Chick, 
as  seen  in  blood  drawn  from  the  heart  on  the  third  day,  is  affirmed  by  Mr.  Ma- 
cleod3  to  present  a  similar  series  of  phenomena.  Indeed,  it  may  be  surmised 
that,  when  a  large  number  of  young  cells  are  simultaneously  or  successively 
evolved  from  the  nucleus  of  a  parent-cell  (§  105),  it  is  by  some  such  mode  of 
development  from  the  individual  particles  composing  the  nucleus ;  for  the  appear- 
ance which  is  presented  when  this  process  is  being  carried  on,  is  very  much  that 
of  the  sprouting  of  its  marginal  granules  into  young  cells  (Fig.  9).  And  it 
seems  probable  that,  wherever  a  single  granule  is  thus  evolved  into  a  cell,  it  has 
been  discharged  as  a  reproductive  particle  from  a  pre-existing  cell ;  its  conditions 
of  development  being  in  this  respect  different  from  those  of  the  granules  which 
form  nuclei  by  their  aggregation  in  the  midst  of  a  plastic  exudation,  and  which, 
not  having  undergone  the  same  preparation,  are  not  endued  with  vital  properties 
of  as  high  a  character. — On  the  whole  of  this  subject,  however,  considerable 
obscurity  still  rests;  and  while  it  is  next  to  certain  that  cells  may  be  generated 
within  the  Human  body  in  each  of  the  modes  now  described,  there  is  still  very 
much  to  be  learned  respecting  the  conditions  under  which  every  form  of  the 
process,  respectively  occurs. 

•  See  Prof.  Bennett's  Treatise  "On  Cancerous  and  Cancroid  Growths,"  p.  146. 

2  See  "Prin.  of  Phys.,  Gen.  and  Comp.,"  \\  142,  267,  a,  Am.  Ed. 

3  "  Lond.  and  Edinb.  Monthly  Journ.,"  Sept.,  1842. 


OF   CELLS   AND   CELL-LIFE.  129 

108.  We  have  now  to  inquire  into  the  nature  of  those  peculiar  phenomena, 
of  which  Cells  are  the  instruments,  and  to  which  the  designation  of  Vital  is  given, 
on  account  of  their  restriction  to  the  living  organism,  and  their  distinctness  from 
those  of  a  physical  or  chemical  nature.     The  series  of  actions  constituting  Cell- 
Development,  under  whichever  of  the  foregoing  modes  it  may  take  place,  is,  of 
all  these  phenomena,  that  which  stands  in  most  complete  opposition  to  anything 
displayed  by  the  Inorganic  world ;  and  we  see  in  it  the  type  of  the  development 
of  the  entire  fabric,  which  essentially  consists  in  the  continual  multiplication  of 
its  component  cells  by  one  or  other  of  the  processes  just  described,  and  in  the 
subsequent  changes  which  they  undergo.     Thus  we  observe  the  appropriation  of 
certain  nutrient  materials,  derived  from  external  sources,  in  the  first  extension 
of  the  cell-wall,  the  enlargement  of  the  nucleus,  and  the  collection  and  increase 
of  the  cell-contents ;  and  upon  these  materials  a  certain  degree  of  transformation 
is  commonly  exerted.     As  already  pointed  out  (§  17),  there  is  but  little  if  any 
chemical  change  needed  for  the  incorporation  of  the  nutrient  materials  with  which 
the  Animal  cell  is  supplied,  into  its  own  substance ;  the  cell-walls  and  nuclei 
being  apparently  of  the  same  chemical  nature  with  the  constituents  of  the  blood, 
at  the  expense  of  which  they  are  developed :  but  we  must  here  recognize  a  vital 
change,  in  virtue  of  which  they  are  rendered  henceforth  capable  of  exhibiting 
actions,  which,  so  long  as  they  remain  mere  chemical  compounds,  they  are  utterly 
unable  to  perform.     The  cell-contents,  on  the  other  hand,  for  the  most  part 
remain  as  mere  chemical  compounds;  and  though  they  are  in  many  instances 
directly  furnished  by  the  nutrient  fluid,  there  are  other  cases  in  which  their  com- 
position is  so  different  from  that  of  anything  it  can  be  shown  to  include,  that  we 
must  reckon,  as  one  manifestation  of  the  peculiar  attributes  of  the  cell,  the  power 
of  Chemical  Transformation.     But  its  power  may  be  also  exerted  in  vitalizing 
its  contents  or  a  certain  portion  of  them ;  this  power  of   Vital  Transformation 
being  probably  possessed  in  a  low  degree  by  many  cells  which  prepare  the  nu- 
trient material  for  its  appropriation  by  the  living  tissues,  but  being  pre-eminently 
the  endowment  of  those  which  are  concerned  in  the  generative  operations. — 
Thus,  then,  in  the  simple  act  of  Cytogenesis,  we  recognize  a  force  in  operation 
which  converts  certain  chemical  compounds  into  a  living  organized  structure,  not 
only  moulding  them  into  a  peculiar  and  characteristic  form,  but  endowing  them 
with  new  attributes.     And  not  the  least  remarkable  of  these  attributes  is  that 
power  of  increase  and  multiplication,  whereby  the  same  alterations  may  be  effected 
in  an  almost  unlimited  amount  of  raw  material;  so  that  an  aggregation  of  organ- 
ized tissue,  sufficient  to  produce  a  fabric  of  considerable  dimensions,  may  be 
thereby  generated  from  a  single  primordial  cell. 

109.  The  history  of  the  life  of  a  Cell  is  by  no  means  completed,  however,  by 
the  fullest  enumeration  of  the  successional  phenomena  exhibited  in  its  develop- 
ment and  multiplication ;  for,  after  it  has  attained  its  full  growth,  it  may  itself 
undergo  alterations  of  various  kinds,  or  may  become  the  instrument  of  effecting 
changes  in  others,  such  as  can  scarcely  be  regarded  in  any  other  light  than  as 
manifestations  of  a  force  identical  with  that  which  was  operative  in  its  original 
production. — Among  the  changes  occurring  in  the  cell  itself,  that  which  may 
be  first  noticed  is  the  permanent  alteration  mform  which  certain  cells  undergo, 
not  from  forces  external  to  them,  but  from  agencies  at  work  in  their  interior. 
Thus,  although  spheroidal  cells  may  be  converted  into  polygonal  by  mutual 
pressure  on  all  sides,  or  may  be  lengthened  towards  the  fusiform  shape  when 
that  pressure  is  less  in  one  direction  than  in  another,  or  may  be  flattened  down 
into  a  scale  by  the  loss  of  its  fluid,  yet  it  is  impossible  to  account  in  any  such 
mode  for  the  extraordinary  elongation  of  certain  cells,  or  for  the  flattening  of 
others,  when  no  pressure  is  being  exerted  upon  them;  or  for  the  extension  of 
offsets  from  others  into  caudate  or  stellate  prolongations  (§  146).     Some  of  these 
cases  are  not  improbably  to  be  accounted  for  by  the  extension  of  the  cell,  whilst 

9 


130         OF   THE    STRUCTURAL   ELEMENTS   OF  THE   HUMAN   BODY. 

still  increasing  in  size,  in  the  direction  of  least  resistance;  in  the  same  manner 
as  the  roots  of  plants  send  forth  their  prolongations,  sometimes  of  extraordinary 
length,  through  the  soil  which  they  can  most  readily  traverse.  But  there  is 
reason  to  believe  that  such  alterations  of  form  may  also  be  effected,  even  after 
the  cells  have  attained  their  full  dimensions,  by  the  agency  of  currents  within 
the  cell,  whose  maintenance  is  intimately  connected  with  its  nutrient  operations, 
and  whose  "  set"  in  particular  directions  determines  the  protrusion  of  the  cell- 
wall  at  the  points  towards  which  they  tend.  It  is  well  known  that  such  currents 
are  frequently  to  be  observed  in  the  cells  of  Plants ;  indeed,  it  seems  probable 
that  they  take  place  in  every  vegetable  cell  at  a  certain  stage  of  its  development.1 
Regular  currents,  apparently  of  a  similar  nature,  and  quite  distinct  from  the 
"  molecular  movements"  which  cannot  be  justly  attributed  to  any  other  than 
physical  causes  (§  101),  have  also  been  witnessed  within  many  Animal  cells : 
thus  Prof.  Sharpey  has  seen  a  clump  of  dark  granular  matter  in  regular  revo- 
lution, and  numerous  separated  granules  coursing  round  and  round,  within  the 
spheroidal  pigment-cells  of  the  tail  of  a  Tadpole.9  Prof.  Czermak  has  described 
peculiar  rotatory  movements  in  certain  vesicles  attached  to  the  fine  extremities 
of  the  seminal  tubes  in  the  salamander.3  Prof.  Kb'lliker  has  observed  analogous 
movements  in  the  cells  of  the  seminal  filaments  of  a  Polyclinum,  and  in  large 
cells  in  the  sprouting  arms  of  a  Medusoid  animal  ;4  and  a  still  more  remarkable 
case,  in  which  the  currents  within  the  cell  distinctly  determined  the  protrusion 
of  the  cell-wall  in  one  direction  or  anotUer,  has  been  witnessed  by  the  Author 
in  one  of  the  lowest  forms  of  animal  life,  and  has  been  elsewhere  described  by 
him  in  detail.5 — On  the  whole,  then,  we  seem  entitled  to  affirm  that  such 
permanent  alterations  in  the  forms  of  cells,  as  cannot  be  explained  by  external 
pressure,  are  dependent  upon  an  agency  of  the  same  kind  with  that  which  is 
concerned  in  the  ordinary  operations  of  development;  and  must  thus  be  re- 
garded as  a  continual  manifestation  of  what  may  be  conveniently  designated 
by  the  term  Cell- force? 

110.  Certain  kinds  of  cells,  however,  exhibit  more  rapid  changes  of  form, 
such  as  cannot  be  so  directly  attributed  to  their  nutritive  operations ;  and  these 
may  take  place  in  such  a  manner,  as  to  communicate  motion  to  objects  external 
to  them.  Moreover,  these  changes  may  take  place  altogether  spontaneously 
(i.  e.,  independently  of  any  external  stimulation),  or  they  may  only  occur  when 
some  exciting  influence  is  communicated  to  the  cell.  Of  both  forms  of  move- 
ment, we  have  numerous  illustrations  in  the  Vegetable  kingdom;  the  rhythmical 
undulations  of  the  elongated  cell-filaments  of  the  Oscillatoriae,  or  the  alternat- 
ing flexures  of  the  stalks  of  the  lateral  leaflets  of  the  Hedysarum  gyrans,  being 
examples  of  the  former;  whilst  the  closure  of  the  fly-trap  of  the  Dionsea,  the 

1  See  "Prin.  of  Phys.  Gen.  and  Comp.,"  \  137,  Am.  Ed. 

2  Introduction  to  Dr.  Quain's  "Elements  of  Anatomy,"  5th  edit.,  p.  65,  Am,.  Ed.,  note. 

3  "Oester.  Medic.  Jahrbucher,"  Jan.  1845  ;  and  "  Brit,  and  For.  Med.  Rev.,"  vol.  xxii. 
p.  264. 

4  "  Entwick.  der  Cephalopoden,"  p.  156. 

s  "  Prin.  of  Phys.  Gen.  and  Comp.,"  p.  244,  Am.  Ed. 

«  The  Author  is  particularly  desirous  that  he  should  be  understood  as  implying  by  this 
term,  not  that  the  force  is  produced  or  generated  by  the  cell,  but  merely  that  the  growth 
of  the  cell  is  the  most  general  manifestation  of  that  force,  to  which  it  is  convenient  to  refer 
as  a  standard  of  comparison ;  and  also  that  the  cell  aifords  the  ordinary  instrumental  con- 
dition for  the  exercise  of  the  force  in  question,  although  it  can  doubtless  be  exerted  in 
many  cases  in  which  cell-development  does  not  take  place.  The  use  which  he  would  make 
of  the  term  is  just  that  which  is  commonly  made  of  the  term  "  engine-power"  in  mechanics ; 
for  the  steam-engine  possesses  no  power  in  itself,  but  is  simply  the  instrument  most  com- 
monly employed,  because  the  most  convenient  and  advantageous  yet  devised,  for  the  appli- 
cation of  the  expansive  force  of  steam,  generated  by  the  application  of  Heat,  to  the  produc- 
tion of  mechanical  motion ;  this  Heat,  which  is  the  real  motive  power,  being  capable  of 
manifesting  itself  in  a  great  variety  of  other  modes. 


OP  CELLS   AND   CELL-LIFE.  131 

folding  of  the  leaves  of  the  Mimosa,  and  the  flexure  of  the  stamen  of  the  Ber- 
berry, upon  mechanical  or  chemical  stimulation,  are  specimens  of  the  latter. 
In  all  these  cases,  the  aptitude  for  the  movement,  whether  "  spontaneous"  or 
"  excited/7  is  so  clearly  dependent  upon  the  general  vital  activity  of  the  cells 
which  perform  it,  that  we  can  scarcely  regard  it  in  any  other  light  than  as  an 
expression  or  manifestation  of  their  peculiar  force.  And  this  view  derives  con- 
firmation from  all  that  we  know  of  the  conditions  under  which  movement  is 
originated  in  Animals.  For  here,  too,  may  it  be  said  that  all  motion  is  depend- 
ent upon  the  change  of  form  of  cells ;  and  that  this  change  may  be  either 
"  spontaneous"  or  excited,"  but  in  both  cases  must  be  regarded  as  a  mani- 
festation of  vital  force.  Of  the  spontaneous  movement,  we  have  the  most  re- 
markable example  in  the  incessant  rhythmical  action  of  the  cilia  (Fig.  26) 
which  line  many  of  the  tubes  and  cavities  of  the  body ;  these  cilia  being,  it 
would  appear,  nothing  else  than  prolongations  of  the  cell  itself,  though  of  ex- 
treme tenuity.  Their  movement  is  obviously  dependent  upon  the  life  of  the 
cell  from  which  they  are  put  forth,  and  is  retarded  or  brought  to  a  stand  by 
agencies  which  tend  to  depress  its  vital  power.  But  these  are  not  the  only 
cases  in  which  cells  appear  to  undergo  rhythmical  changes  of  form,  as  a  part  of 
their  regular  vital  operations;  for  the  alternating  contractions  and  dilatations  of 
the  cavities  of  the  heart  appear  due  to  an  action  of  this  kind  in  its  muscular 
walls;  and  we  may  not  improbably  regard  the  contraction  of  the  uterine  struc- 
ture, when  it  has  reached  a  certain  stage  of  its  development,  in  the  same  light. 
In  both  these  cases,  it  is  true,  it  is  to  be  observed  that  the  structures  in  question 
are  peculiarly  amenable  to  the  influence  of  stimuli;  thus  the  rhythmical  action 
of  the  heart  may  be  re-excited,  after  it  has  been  suspended,  by  a  slight  mechani- 
cal irritation,  and  its  regular  movements  may  be  either  accelerated  or  retarded 
by  nervous  influence ;  so,  again,  the  parturient  efforts  of  the  uterus  may  be  in- 
duced, when  they  would  not  otherwise  take  place,  by  mechanical  or  nervous 
stimulation,  or,  when  they  are  already  going  on,  they  may  be  accelerated  or  re- 
tarded by  the  same  agency.  But  still,  when  every  source  of  excitement  is  ex- 
cluded, we  cannot  but  perceive  that  these  actions  take  place  with  a  spontaneity 
which  can  scarcely  be  accounted  for  in  any  other  way  than  by  considering  them 
as  expressions  of  the  vital  activity  of  the  component  cells  of  these  forms  of 
muscular  tissue,  which  manifests  itself  in  this  mode  when  the  developmental 
life  of  the  cell  has  attained  its  maturity.  And  this  view  is  strikingly  confirmed 
by  what  we  know  of  the  origin  and  termination  of  these  movements.  For  the 
action  of  the  heart  commences,  when  as  yet  its  contractile  parietes  consist  but 
of  an  assemblage  of  ordinary-looking  cells,  no  proper  muscular  tissue  being 
evolved,  and  no  nervous  system  being  yet  developed  from  which  the  stimulus 
to  the  movement  can  proceed ;  and  it  is  impossible  to  assign  any  other  cause  for 
the  movement  under  such  circumstances,  than  the  attributes  inherent  in  the 
tissues  which  perform  it.  So,  again,  as  will  be  shown  hereafter  (CHAP.  XIX. 
SECT.  3),  the  parturient  action  of  the  uterus  cannot  be  fairly  attributed  to  any 
of  the  agencies  which  have  been  supposed  to  excite  it ;  but  must  be  looked 
upon  as  one  of  those  phenomena,  whose  periodical  recurrence  is  due  to  the 
regularity  of  the  operations  of  growth,  whereby  the  tissue  attains  its  maturity 
in  a  certain  limited  time,  and  then  discharges  itself  of  its  vital  force  in  the 
shape  of  motor  power;  just  as  another  cell  will  consume  it  in  the  development 
of  a  brood  of  young  ones,  or  in  the  performance  of  chemical  transformations, 
setting  free  the  product,  when  completely  formed,  by  its  own  rupture  or  deli- 
quescence. And  the  subsequent  result  is  just  what  on  this  view  might  be  an- 
ticipated ;  for  the  vital  power  of  the  tissue  being  thus  exhausted,  it  speedily 
undergoes  degeneration  and  death ;  and  thus  it  is  that  the  reduction  of  the 
uterus  to  its  normal  size  takes  place  so  much  more  rapidly  after  parturition,  than 
does  the  wasting  of  ordinary  muscles  by  simple  disuse.  Hence  we  may  look 


132         OF   THE   STRUCTURAL   ELEMENTS   OF   THE   HUMAN   BODY. 

upon  the  development  of  the  muscular  substance  of  the  uterus,  which  is  going 
on  during  the  whole  period  of  gestation,  as  in  reality  consisting  in  the  accumu- 
lation of  a  vast  reservoir  of  cell-force,  which  is  to  be  consumed  in  one  powerful 
effort.  The  contraction  of  the  muscles  ordinarily  termed  "voluntary,"  which 
also  will  be  shown  hereafter  to  be  dependent  upon  changes  of  form  taking  place 
in  the  cells  of  their  component  fibrillae,  is  not  of  the  "  spontaneous/'  but  of  the 
"  excited"  kind;  but  here,  too,  we  have  evidence  that  the  mechanical  movement 
is  to  be  regarded  but  as  an  expression  of  vital  force,  in  the  fact  (now  universally 
admitted  by  Physiologists)  that  every  act  of  muscular  exertion  necessarily  in- 
volves as  its  condition  the  disintegration  of  a  certain  amount  of  muscular  tissue, 
whose  components  are  then  removed  as  effete  by  the  excretory  processes ;  tso 
that  we  may  look  upon  the  death  of  such  cells,  whose  term  of  life  might  other- 
wise have  been  considerably  prolonged,  as  the  result  of  the  expenditure  of  their 
peculiar  modification  of  force,  under  the  guise  of  mechanical  power. 

111.  What  has  been  said  of  the  cells  which  possess  the  attribute  of  motility^ 
is  also  true  of  that  still  more  remarkable  order  of  cells,  peculiar  to  the  Animal 
kingdom,  by  whose  agency  Nerve-force  is  developed.  The  nature  of  this  force, 
and  its  relations  to  Electricity  and  other  physical  agencies,  will  be  discussed 
hereafter  (CHAP.  v.  SECT.  7);  but  at  present  it  will  be  sufficient  to  state,  that 
there  can  be  no  reasonable  doubt  of  the  dependence  of  its  production,  in  the 
central  organs,  upon  the  development  of  the  peculiar  cells  which  constitute  their 
ganglionic  or  vesicular  substance ;  and  that  the  progress  of  physiological  inquiry 
seems  to  justify  the  belief  (long  since  entertained  and  expressed  by  the  Author), 
that  cells  or  cell-nuclei  are  usually  the  agents  in  the  origination  of  nerve-force 
at  the  peripheral  extremities  of  the  nerve-fibres.  This  nerve-force  may  be  re- 
garded as  the  very  highest  manifestation  of  Vital  Power,  in  virtue  alike  of  its 
intimate  relation  with  Mental  agency,  which  it  serves  to  excite,  and  by  which  it 
is  in  turn  excited  (CHAP,  xiv.),  of  its  power  of  exciting  or  checking  Muscular 
movements,  and  of  the  control  it  exerts  over  the  Vital  operations  of  cells  in 
general,  whether  these  take  the  form  of  multiplication  or  of  chemico-vital  trans- 
formation, or  present  themselves  under  any  other  aspect.  For,  so  obvious  is  the 
controlling  and  regulating  action  of  the  Nervous  System,  where  (as  in  Man),  it 
attains  its  highest  development,  over  those  acts  of  nutrition,  secretion,  &c., 
which  essentially  consist  in  the  production  and  growth  of  cells,  that  many 
Physiologists  have  regarded  these  actions  as  necessarily  dependent  upon  the 
exercise  of  nervous  power.  For  this  assumption,  however,  there  is  no  evidence 
whatever;  and  it  is  strongly  opposed  by  the  fact,  that  these  actions  are  per- 
formed under  conditions  essentially  the  same  as  they  are  in  the  Vegetable  king- 
dom, in  which  nervous  power  has  no  existence.  And  all  the  phenomena  which 
have  been  adduced  in  its  support,  are  fully  capable  of  being  scientifically  ex- 
pressed by  the  view  here  advocated;  for  just  as  Electricity  developed  by  chemi- 
cal change  may  operate  (by  its  correlation  with  chemical  affinity)  in  producing 
other  chemical  changes  elsewhere,  so  may  Nerve-force,  which  has  its  origin  in 
cell-formation,  excite  or  modify  the  process  of  cell-formation  in  other  parts,  and 
thus  influence  all  the  vital  manifestations  of  the  several  tissues,  whatever  may 
be  their  own  individual  characters.  Further,  we  have  evidence  in  the  phe- 
nomena of  Nervous  action  (CHAP.  v.  SECT.  7),  that  the  production  of  Nerve- 
force,  like  the  development  of  Muscular  power,  involves  the  degeneration  and 
death  of  a  certain  amount  of  the  tissue  which  serves  as  its  instrument ;  so  that 
we  are  furnished  by  this  fact  with  an  additional  reason  for  the  belief,  that  nerv- 
ous agencv  is  to  be  regarded  as  but  a  peculiar  modus  operandi  of  the  same  force 
as  that  which  is  elsewhere  operative  in  cell-development. 

112.  Thus,  then,  we  have  distinguished  the  following  as  the  principal  mani- 
festations of  Cell-Life : — 


OF   CELLS   AND   CELL-LIFE.  133 

a.  Growth  of  the  original  cell,  from  its  germ  to  its  maturity ;  involving 

the  selection  and  appropriation  of  its  materials. 

b.  Multiplication,  by  the  subdivision  either  of  the  original  cell  or  of  its 

nucleus. 

c.  Chemical  Transformation,  exerted  upon  the  pabulum  of  the  cell,  where- 

by new  products  may  be  generated  in  its  interior. 

d.  Vitalization  of  a  portion  of  the  pabulum,  whereby  it  becomes  endowed 

with  vital  properties  of  its  own,  so  as  even  to  originate  cells  de  novo. 

e.  Permanent  Changes  of  Form,  taking  place  in  connection   with  acts  of 

growth,  and  giving  a  peculiar  character  to  the  tissue. 

/.  Temporary  Changes  of  Form,  applied  to  the  generation  of  mechanical 
force,  and  to  the  production  of  sensible  motions. 

g.  Production  of  Nerve-Force,  which  may  affect  all  the  preceding  opera- 
tions, and  which  is  intimately  related  to  Mental  agency. 

The  first  five  of  these  are  manifested  in  those  constructive  operations,  which  are 
common  alike  to  the  Plant  and  to  the  Animal,  and  which  consist  in  the  building- 
up  of  the  organized  fabric.  Of  this  organized  fabric,  on  the  other  hand,  the 
exercise  of  the  last  two  may  be  regarded  as  essentially  destructive  ;  since  they 
involve  an  expenditure  of  that  force  which  previously  held  together  the  compo- 
nents of  the  tissues,  whereby  these  components  are  given  up  to  the  disintegrat- 
ing agency  of  the  Chemical  and  Physical  forces.  But  it  is  in  the  exercise  of 
Nervo-Muscular  power  that  the  Life  of  the  Animal  essentially  consists;  and  the 
constructive  operations  which  take  place  in  its  fabric  (as  will  be  more  fully 
shown  hereafter,  CHAP.  VI.),  may  be  regarded  as  essentially  destined  to  provide 
its  material  and  dynamical  conditions. 

113.  That  these  various  phenomena  are  to  be  regarded  as  manifestations  of 
one  and  the  same  Vital  Force,  of  which  the  several  modifications  of  Organic 
Structure  that  exhibit  them  are  the  respective  instruments,  may  be  argued,  not 
merely  from  the  facts  already  urged,  but  also  from  the  community  of  origin  of 
all  the  tissues  and  organs  of  each  individual,  in  a  single  primordial  cell.  For, 
like  the  humblest  forms  of  Vegetable  and  Animal  life  which  permanently  con- 
sist of  separate  and  independent  cells,  the  embryo  of  even  the  highest  types  of 
each  kingdom,  in  the  earliest  phase  of  its  development,  is  but  a  single  cell ;  and 
during  the  earlier  period  of  its  increase,  we  observe  that  it  displays  only  that 
most  general  manifestation  of  cell-force  which  consists  in  growth  and  multipli- 
cation. The  descendants  of  this  parent-cell,  however,  soon  begin  to  undergo  a 
variety  of  transformations,  and  to  assume  a  diversity  of  characters ;  and  we  ob- 
serve, in  fact,  that  a  sort  of  "division  of  labor"  takes  place  among  them,  each 
group  of  cells  being  appropriated  to  some  particular  office,  and  discharging  it 
alone  to  the  exclusion  of  the  rest;  as  if,  by  this  special  direction  of  the  vital 
force,  the  cell  which  is  its  instrument  is  unfitted  for  any  other  kind  of  vital 
agency.  Of  this  relation  of  reciprocity  between  the  several  manifestations  of 
vital  power,  the  following  examples,  among  many  others,  may  be  cited. — "Where 
the  whole  energy  of  the  cell  is  directed  to  multiplication,  we  do  not  observe 
either  chemical  transformation,  or  change  of  form,  or  development  into  any  other 
tissue;  nor  do  we  find  that  either  motor  power  or  nerve-force  is  generated.  Of 
this  we  have  already  had  an  example  in  that  early  phase  of  embryonic  life,  in 
which  cell-multiplication  takes  place  with  extraordinary  rapidity.  In  the  for- 
mation of  new  parts  which  make  their  appearance  at  a  subsequent  time,  we  find 
that  their  foundation  is  laid  in  a  mass  of  cells  which  rapidly  multiply,  up  to  a 
certain  point  (like  those  of  the  embryonic  mass),  without  any  change  of  form  or 
character ;  and  that,  when  they  have  once  begun  to  undergo  development  into 
other  kinds  of  tissue,  they  multiply  no  longer.  So,  again,  in  those  cancerous 
growths,  whose  rapid  increase  is  one  of  their  most  important  distinctive  features, 


134         OF   THE   STRUCTURAL   ELEMENTS   OF   THE   HUMAN   BODY. 

we  usually  observe  that  the  whole  texture  retains  its  primitive  cellular  charac- 
ter ;  and  that  the  development  of  higher  forms  of  tissue  only  occurs  in  those 
whose  growth  is  slower,  their  cells  having  ceased  to  multiply  themselves  thus 
rapidly,  when  they  underwent  histological  change.  But  perhaps  one  of  the 
most  striking  examples  of  this  principle  is  presented  by  those  glandular  follicles 
which  act  as  parent-cells,  developing  in  their  interior  a  successional  progeny, 
which  are  the  true  secreting  cells :  for  the  former  possess  no  secreting  power, 
their  vital  force  being  expended  in  the  production  of  the  latter ;  whilst  on  the 
other  hand,  the  latter  possess  no  reproductive  power,  but  die  and  are  cast  off 
when  they  have  reached  their  maturity,  even  their  own  cell-walls  being  usually 
very  imperfectly  developed  (§  117),  as  if  their  whole  vital  force  had  been  ex- 
pended in  the  secreting  process. — So,  again,  the  cells  whose  vital  force  is  exerted 
in  mechanical  movement,  seem  exclusively  adapted  for  this  purpose,  apparently 
performing  no  other  vital  changes  than  those  involved  in  their  own  develop- 
ment. Thus,  the  ciliated  epithelium-cells  which  line  the  respiratory  passages 
and  the  ducts  of  many  glands,  appear  never  to  perform  that  secretory  function 
which  is  discharged  by  other  non-ciliated  cells  of  the  same  stratum ;  so  that, 
their  mode  of  production  and  the  general  conditions  of  their  development  being 
essentially  the  same,  we  can  scarcely  fail  to  regard  the  ciliary  movement  and 
the  secreting  action  as,  however  dissimilar  in  themselves,  two  modes  of  opera- 
tion of  one  and  the  same  "  cell-force/7  Again,  the  elongated  cells  which  con- 
stitute the  non-striated  muscular  fibre,  and  the  minute  cellules  of  which  the 
fibrillae  of  the  striated  muscular  fibre  are  made  up,  seem  to  exercise  no  chemical 
change,  to  undergo  no  further  development,  and  to  undergo  disintegration 
without  having  previously  multiplied  themselves ;  so  that  all  increase  and  re- 
generation of  muscular  tissue  appear  to  take  place,  either  by  production  de  novo, 
or  possibly  (in  the  case  of  the  striated  fibre)  by  the  continued  development  of 
new  cells  from  the  nucleus  of  the  parent-cell,  which,  like  that  of  the  glandular 
follicle,  performs  no  other  function  than  that  of  multiplication. — The  cells  com- 
posing the  nervous  tissue,  again,  do  not  show  any  indication  of  reproductive 
power,  and  seem  to  undergo  disintegration  as  the  direct  consequence  of  their 
production  of  nerve-force ;  so  that  they,  too,  appear  to  expend  their  whole  vital 
energy  in  one  particular  mode  of  action,  and  to  have  no  power  to  spare  for  any 
other. 

114.  We  have  hitherto  spoken  only  of  that  part  of  the  Life  of  the  Cell,  which 
intervenes  between  its  origin  and  its  epoch  of  maturity ;  we  have  now  to  advert 
to  its  decline  and  death ;  and  these  are  to  be  regarded,  no  less  than  the  pre- 
ceding, as  part  of  that  regular  series  of  changes  by  which  it  is  distinguished  as 
an  organized  structure.  For  it  may  be  stated  as  a  general  rule,  that  the  amount 
of  vital  action  which  can  be  peformed  by  each  living  cell  has  a  definite  limit ; 
an4  that  when  a  certain  point  has  been  once  reached,  a  diminution  in  the  vital 
activity  of  the  cell  must  ensue,  and  it  must  become  more  and  more  subject  to 
those  influences  which  are  constantly  tending  to  degrade  it  to  the  condition  of 
inorganic  matter.  Hence  there  is  for  the  most  part  a  limit  to  the  duration  of 
each  component  cell  of  the  organism,  which  is  quite  irrespective  of  that  of  the 
organism  at  large;  the  life  of  the  latter  being  maintained  by  the  continual  de- 
velopment of  new  tissues,  in  the  place  of  those  which  are  degenerating  and  de- 
caying. But  this  limit  is  by  no  means  constant ;  since  a  cell  may  live  faster  or 
slower,  that  is,  it  may  put  forth  a  greater  or  less  degree  of  vital  energy  in  a 
given  time,  in  accordance  with  the  conditions  under  which  it  is  placed ;  and  the 
more  rapid  the  rate  of  life,  the  more  brief,  cseteris paribus,  is  its  duration.  Of 
this  general  principle,  abundant  examples  are  afforded  to  us  in  the  Vegetable 
kingdom,  in  which  we  can  readily  trace  the  operation  of  varying  degrees  of  light 
and  heat ;  but  it  is  not  difficult  to  trace  them  out  also  in  cold-blooded  animals  \ 
and  the  only  reason  for  the  greater  constancy  in  the  rate  of  decay  and  renova- 


OF   CELLS   AND   CELL-LIFE.  135 

tion  of  the  tissues  in  warin-blooded  animals,  seems  to  lie  in  the  uniformity  of 
the  temperature  at  which  they  are  kept,  which  uniformity  tends  to  produce  a 
determinate  regularity  in  the  rate  of  their  vital  activity  (§  127).  As  already 
remarked,  the  very  influences  which  call  into  action  the  vital  properties  of  a 
living  tissue,  tend  to  produce  its  decay,  when  it  no  longer  possesses  the  faculty 
of  turning  them  (so  to  speak)  to  this  account ;  and  thus  it  is  that,  in  warm- 
blooded animals,  the  cessation  of  those  changes  in  which  life  consists,  immedi- 
ately leaves  the  way  clear  for  that  disintegration  which  is  effected  by  Chemical 
forces,  and  this  the  more  actively  as  the  temperature  is  higher.  The  only  tis- 
sues, indeed,  that  can  resist  the  operation  of  these  forces  are  such  as,  in  virtue 
of  their  peculiar  composition,  are  not  readily  affected  by  them.  Thus  we  find 
that  bones,  teeth,  hairs,  &c.,  may  have  their  existence  almost  indefinitely  pro- 
longed, without  any  sensible  degeneration,  after  the  complete  cessation  of  all 
vital  changes  in  their  substance  ;  since  that  very  consolidation  of  these  tissues, 
which  put  them  out  of  the  pale  of  active  life,  at  the  same  time  rendered  them 
less  subject  than  before  to  the  degrading  influence  of  Chemical  agencies.  Even 
the  softest  and  most  decomposable  of  the  tissues  may  be  preserved  from  decay, 
provided  that  they  are  either  kept  at  a  sufficiently  low  temperature,  or  are  en- 
tirely secluded  from  oxygen,  or  are  completely  deprived  of  their  moisture ;  either 
of  which  conditions  is  incompatible  with  the  persistence  of  vital  activity.  And 
thus  it  happens  that  not  only  the  seeds  of  Plants,  but  many  Animal  organisms 
of  a  high  degree  of  development,  may  be  kept  in  a  dormant  condition  for  an. 
unlimited  period,  by  the  reduction  of  their  temperature  or  the  withdrawal  of 
the  liquid  components  of  their  structure;  ready  for  a  renewal  of  their  vital  ac- 
tivity, whenever  the  deficient  conditions  may  be  supplied.1 

115.  The  different  behavior  (to  use  a  term  now  naturalized  in  Chemical 
Science)  of  the  living  and  of  the  dead  organism  under  the  same  conditions,  is 
commonly  accounted  for  by  the  supposition,  that  the  Vital  force,  so  long  as  it 
endures,  antagonizes  the  operation  of  the  Physical  and  Chemical  agencies,  which 
are  constantly  tending  to  the  disintegration  of  the  living  structure ;  and  that, 
so  soon  as  the  former  is  extinct,  the  latter  can  exert  their  influence  without 
restraint  or  opposition.  But  against  this  doctrine,  several  cogent  objections  may 
be  adduced.  For  in  the  first  place,  the  conditions  most  favourable  to  the  decay 
of  the  organism  after  its  death,  are  those  which  are  not  only  most  favorable,  but 
are  absolutely  essential,  to  its  life,  whilst  it  retains  its  vital  properties ;  the 
presence  of  Water  being  requisite  for  all  the  transformations  which  the  nutrient 
materials  undergo,  as  well  as  for  the  very  construction  of  a  cell ;  the  presence 
of  Oxygen  being  necessary  for  the  greater  number,  if  not  for  the  whole,  of  the 
chemical  actions  which  the  life  of  the  cell  involves ;  and  the  dynamical  agency 
of  Heat  being  so  completely  indispensable,  that  the  amount  of  Vital  Action  put 
forth  may  be  almost  considered  as  the  definite  equivalent  of  the  amount  of  this 
power  that  is  in  operation.3  But  if  more  than  a  certain  measure  of  these  powers 
should  be  exerted,  the  effect  is  not  beneficial,  but  injurious,  to  the  living  organ- 
ism, which  is  then  acted  on  as  if  it  were  composed  of  dead  matter.  Thus  we 
see  that  whilst  to  every  living  being  there  is  a  certain  range  of  temperature, 
more  or  less  limited,  within  which  its  vital  activity  is  normally  exercised,  any 
considerable  elevation  above  that  standard  occasions  a  perversion  of  that  activity, 
which  tends  to  its  destruction ;  and  a  heat  sufficient  for  the  decomposition  of 
its  organic  constituents  is  not  less  effectual  in  producing  this  change  on  the  liv- 
ing body,  than  it  is  on  the  dead.  So,  whilst  the  respiration  of  atmospheric  air 
is  necessary  for  almost  every  manifestation  of  life,  the  introduction  of  undiluted 
oxygen  into  the  system  is  speedily  fatal,  apparently  through  the  violence  of  the 

'  See  "Prin.  of  Phys.,  Gen.  and  Comp.,"  CHAP.  in.  SECT.  4,  Am.  Ed. 

2   Op.  Cit.,  CHAP.  III.  SECT.  3. 


136         OF   THE   STRUCTURAL   ELEMENTS   OF   THE   HUMAN   BODY. 

actions  which  it  excites. — So,  again,  if  we  observe  the  operation  of  other  agen- 
cies than  those  to  which  reference  has  hitherto  been  principally  made,  we  notice 
that  they  either  modify  its  vital  action,  or  entirely  destroy  its  vital  activity. 
Thus,  a  moderate  current  of  Electricity  appears  to  promote  or  retard  the  nutri- 
tive or  other  operations,  according  as  it  favors  or  antagonizes  the  chemico-vital 
changes  which  they  involve  ;4  whilst  a  violent  shock  is  at  once  destructive  of 
life,  a  more  powerful  discharge  being  required  as  the  bulk  of  the  animal  is 
greater.  So,  again,  we  find  that  various  Chemical  agents  exert  a  very  definite 
influence  on  the  living  body ;  their  forces  not  being  kept  at  bay  by  its  Vital 
powers,  but  manifesting  themselves  either  in  the  modification  of  its  vital  opera- 
tions, or  in  the  destruction  of  its  living  tissue.  Of  the  former  class  of  effects, 
we  have  a  good  illustration  in  the  action  of  what  are  termed  the  irritant  poisons ; 
these,  for  the  most  part,  being  substances  which  are  known  to  have  a  definite 
chemical  relation  to  the  components  of  the  living  tissues,  and  which  tend,  by 
entering  into  new  combinations  with  them,  to  interfere  with  those  changes  in 
which  vital  activity  essentially  consists.  Thus,  Arsenic  and  Corrosive  Sublimate 
form  combinations  with  Albumen,  of  such  stability  that  they  are  among  the 
most  perfect  preservatives  of  dead  tissues  which  we  possess;  and  hence,  even  if 
they  do  not  absolutely  withdraw  the  Albuminous  constituents  of  the  living  tis- 
sues from  their  normal  combinations,  tkey  tend  to  do  so,  and  by  thus  interfering 
with  the  action  of  the  vital  forces,  occasion  that  perversion  of  the  nutrient 
operations  which  manifests  itself  as  Inflammation.3  A  more  energetic  Chemical 
action  is  exerted,  however,  by  the  Corrosive  poisons,  which  operate  upon  the 
living  tissues,  not  in  modifying  their  vital  activity,  but  (by  completely  changing 
the  state  of  their  organic  constituents)  in  putting  a  complete  and  entire  check 
to  it;  and  there  is  no  reason  to  regard  the  Chemical  changes  which  they  occa- 
sion in  the  living  tissues,  as  in  any  degree  different  from  those  which  they  would 
effect  on  substances  of  the  same  composition  not  endowed  with  life.  A  still 
more  remarkable  influence  is  exerted  by  those  "  ferments"  or  Septic  poisons, 
which  have  a  special  power  of  exciting  and  promoting  decomposition  in  the 
components  of  the  tissues  (§  19)  ;  for  of  these,  the  introduction  of  an  extremely 
minute  quantity  into  the  organism  is  sufficient  to  pervert  or  even  to  destroy  its 
entire  vital  activity.  Those  of  the  less  potent  kind  appear  to  act,  not  by  at 
once  checking  the  nutritive  operations,  but  by  lowering  or  degrading  them; 
accelerating  the  stage  of  degeneration  in  the  tissues  which  are  already  in  a 
state  of  vital  activity,  and  preventing  the  newly-originating  tissues  from  attain- 
ing their  normal  perfection  either  of  structure  or  of  action,  so  that  the  degene- 
rative stage  in  them  also  is  more  speedily  induced.  But  there  are  some  which 
appear  to  be  capable  of  putting  an  almost  immediate  stop  to  all  the  vital  opera- 
tions of  the  system,  in  virtue  of  the  changes  of  composition  which  they  effect ; 
and  here  too  we  observe,  that  the  poisons  which  are  most  powerfully  destructive 
of  life,  are  those  which  induce  the  most  rapid  degradation  of  the  organic  com- 
ponents of  the  tissues  to  the  state  of  inorganic  compounds,  as  is  shown  by  the 
very  speedy  decay  of  the  bodies  of  those  who  have  died  from  the  bites  of  ser- 
pents, malignant  fevers,  &c.,  a  state  of  putrescence  manifesting  itself  in  many 
instances  even  before  life  is  extinct. 

116.  Thus,  then,  we  may  state  it  as  a  general  fact,  that,  so  far  from  the  Living 
Organism  having  the  power  of  resisting  the  operation  of  Chemical  and  Physical 
Agencies,  it  is  completely  amenable  to  them;  but  that  certain  of  them  exert 
their  influence  upon  it  in  a  mode  very  different  from  that  in  which  they  act  on 
dead  matter,  affording,  in  fact,  the  material  and  dynamical  conditions  requisite 

'  "Prin.  of  Phys.,  Gen.  and  Comp.,"  gg  107-112,  Am.  Ed. 

2  This  condition  will  be  shown  hereafter  (CHAP.  xi.  SECT.  3)  to  involve  a  lowering  of  the 
vital  powers  of  the  solid  tissues  which  it  affects. 


OF   FREE   NUCLEI   AND   THEIR  ACTIONS.  137 

for  the  maintenance  of  its  vital  activity ;  whilst  others  modify  and  pervert  that 
activity  without  destroying  it,  so  as  to  give  rise  to  morbid  actions;  the  effects 
of  others,  again,  being  so  completely  antagonistic  to  all  vital  activity,  that  it  is 
at  once  checked  by  them.  And  we  shall  hereafter  see  reason  to  believe,  that 
just  as  the  unorganized  pabulum  provided  for  the  nutrition  of  the  structure,  is 
converted  by  the  act  of  Organization  into  the  living  cell,  so  the  Physical  and 
Chemical  forces  whose  influence  promotes  that  organization  are  really  metamor- 
phosed (so  to  speak)  into  Vital  power  by  the  instrumentality  of  the  cell-germ, 
so  that  all  the  forms  of  "  cell-force"  are  thus  immediately  derived  from  them. 
It  is,  however,  inherent  in  the  very  nature  of  the  living  organism  that  this 
instrumentality  should  only  persist  for  a  limited  time.  The  changes  involved 
in  the  process  of  organization  have  the  effect  of  rendering  the  organic  structure 
less  and  less  instrumental  in  determining  this  metamorphosis  of  force;  and  thus 
a  time  arrives,  when  the  capacity  of  development  is  exhausted,  and  when  the 
physical  and  chemical  forces,  no  longer  turned  to  the  account  of  vital  activity, 
begin  to  exert  a  disintegrating  power.  Hence  in  the  Life  of  each  cell,  there  is 
a  period  in  which  its  peculiar  attributes  are  undergoing  augmentation,  an  epoch 
of  perfection,  a  period  of  decline,  and  an  epoch  of  entire  cessation ;  and  the  latter 
is  forthwith  succeeded  (save  in  the  exceptional  cases  already  referred  to,  §  114), 
by  the  decay  of  the  structure.  And  in  proportion  to  the  degree  of  vital  energy 
which  the  cell  possesses  (that  is,  to  its  power  of  turning  Chemical  and  Physical 
agencies  to  its  own  account,  instead  of  being  itself  perverted  by  them),  will  it 
be  able  to  resist  the  operation  of  influences  which  tend  to  its  disintegration.  All 
this  is  true,  as  will  be  shown  hereafter  (SECT.  3),  of  the  organism  at  large,  as 
well  as  of  the  single  cell ;  in  fact,  the  entire  organism,  commencing  in  a  single 
cell,  and  developed  through  the  multiplication  of  cells,  may  be  considered,  even 
at  its  fullest  development,  as  exhibiting,  distributed  (as  it  were)  through  its 
various  component  parts,  all  those  attributes  which  have  now  been  described  as 
characteristic  of  cells  in  general;  and  the  phenomena,  not  merely  of  normal  life, 
but  of  disease,  and  of  the  influence  of  morbific  and  remedial  agents,  will  be  found 
to  be  so  many  illustrations  of  the  doctrines  now  enunciated.  It  is  indeed  sur- 
prising, that  with  this  mass  of  familiar  facts  continually  presenting  themselves 
to  the  observation  of  Physiologists,  any  such  doctrine  should  have  held  its  ground, 
as  that  the  living  organism  withdraws  its  components  from  the  domain  of  Phy- 
sical and  Chemical  forces;  and  only  restores  them  to  the  authority  of  these, 
when  it  has  itself  lost  the  supremacy  of  the  "Vital  Principle"  or  "Organic 
Agent"  which  was  supposed  to  hold  possession  of  the  living  organized  body. 

117.  Of  Free  Nuclei  and  their  Actions. — Although  the  "  Cell"  has  been 
spoken  of  as  the  type  of  organic  structure,  and  the  "  Cell-force"  as  the  most 
general  form  of  vital  agency,  yet  it  must  not  be  left  out  of  view  that  there  is 
strong  evidence  of  the  presence  of  similar  attributes  in  bodies  resembling  cell- 
nuclei,  which,  although  they  may  never  go  on  to  be  developed  into  cells,  appear 
to  be  the  instruments  of  vital  operations  of  a  very  determinate  kind.  This  is  espe- 
cially the  case,  as  first  pointed  out  by  Mr.  Simon,1  in  the  case  of  the  so-called 
"  Vascular  Glands,"  whose  elaborating  influence  is  exercised  upon  materials  which 
are  withdrawn  from  the  current  of  the  circulation  only  to  be  restored  to  it  again ; 
there  being  here  obviously  not  the  same  necessity  fora  limitary  membrane,  as  where 
the  material  drawn  by  the  nucleus  of  the  secreting  cell  around  itself,  is  destined 
to  be  completely  separated  and  to  be  cast  forth  through  another  channel.  There 
are  various  cases,  however,  even  among  the  ordinary  secreting  structures,  in 
which  the  cell-membrane  seems  to  be  wanting,  free  nuclei  being  found  both  in 
the  organ  and  in  the  secreted  fluid ;  this  is  especially  the  case,  for  example,  in 
the  gastric  glands.  And  generally  it  may  be  remarked,  as  Mr.  Simon  has  pointed 

1  "Physiological  Essay  on  the  Thymus  Gland,"  p.  84. 


138 


OF   THE    STRUCTURAL   ELEMENTS   OF   THE   HUMAN   BODY. 


out  (toe.  cit.),  that  the  cell-wall  of  secreting  cells  is  much  less  perfectly  formed 
than  that  of  the  cells  which  are  to  remain  as  components  of  the  solid  tissues,  and 
has  a  much  greater  tendency  to  deliquescence,  whereby  the  contents  of  the  cell 
are  set  free. — Again,  the  presence  of  nuclei  appears  to  exert  an  influence,  as 
will  be  presently  shown,  on  the  production  of  fibres  in  the  midst  of  an  organiza- 
ble  blastema ;  and  there  seems  reason  to  think,  also,  that  the  yellow  or  elastic 
fibres  are  formed  by  the  linear  extension  of  the  nuclei  themselves  (§  224). 
Some  forms  of  basement-membrane,  too,  seem  to  be  composed  of  aggregations  of 
nuclear  particles,  which  not  improbably  serve  as  the  instruments  of  promoting 
vital  operations  in  organizable  fluids  in  their  proximity.  These  facts  concur  with 
those  already  cited  (§  102),  to  support  the  view  that  the  nucleus  is  that  compo- 
nent of  the  Cell  through  which  its  peculiar  powers  are  chiefly  exerted. 

118.  Of  Simple  Fibres;  their  Formation  and  Properties. — That  all  the 
Animal  tissues  have  their  origin  in  Cells,  so  that  even  the  widest  diversities  of 
type  are  reducible  to  the  same  category,  was  the  doctrine  originally  put  forth  by 
Schwann,  who  first  attempted  to  generalize  the  phenomena  (most  of  them  dis- 
covered by  his  own  observations)  which  are  presented  by  their  development. 
By  subsequent  research,  however,  it  has  been  shown  that  this  statement  was  too 
hasty }  and  that,  although  many  of  the  tissues  retain  their  primitive  cellular 
type  through  life,  and  many  more  are  evidently  generated  from  cells  which  sub- 
sequently undergo  metamorphosis,  there  are  some  in  which  scarcely  any  other 
cell-agency  can  be  traced  than  that  concerned  in  the  preparation  of  the  plastic 
material.  This  would  seem  to  be  the  case  especially  with  those  Simple  Fibrous 
Tissues,  hereafter  to  be  described  (CHAP.  v.  SECT.  1),  which  make  up  a  very 
considerable  proportion  of  the  bulk  of  the  body.  For  although  it  seems  indu- 
bitable that  they  may  be  formed  by  the  transformation  of  cells,  and  although 
they  probably  are  thus  generated  in  the  first  development  of  the  organism,  yet 
their  subsequent  production  (especially  in  the  reparation  of  injuries  under  favor- 
able circumstances)  seems  to  be  effected  by  the  fibrillation  of  an  "  organizable 
blastema"  (§§  26-28).  Even  here  the  course  and  direction  of  the  fibres  seem 
often  to  be  determined  by  the  nuclear  particles  which  the  fibrillating  substance 
includes;  for  in  the  reproduction  of  tendinous  tissue,  as  observed  by  Mr.  Paget,1 
the  nuclei  are  formed  and  become  elongated  before  any  fibrillation  is  visible,  and 
the  fibrillation  takes  place  in  the  direction  in  which 
they  lie,  so  that  each  nucleus  is  imbedded  in  a  fasci- 
culus of  fibres;  and  a  similar  relation  has  been  pointed 
out  by  Mr.  Addison,3  who  has  remarked  that  the  fibres 
which  are  formed  during  the  coagulation  of  the  Liquor 
Sanguinis  or  in  other  plastic  exudations,  often  seem 
to  radiate  from  the  cells  or  nuclear  corpuscles  which 
these  fluids  may  contain  (Fig.  10).  These  facts  give 
a  sufficient  explanation  of  the  presence  of  nuclei  in 
the  midst  of  the  simple  fibrous  tissues,  which  has 
been  adduced  in  support  of  the  doctrine  of  their  ori- 
gin in  cells. — A  very  marked  example  of  the  produc- 
tion of  fibres  in  the  midst  of  an  organizable  substance, 
without  any  direct  intervention  of  cells,  is  afforded 
by  Fibro-  Cartilage  ;  the  various  forms  of  which  pre- 
sent every  gradation  between  the  perfectly  homoge- 
neous intercellular  substance  of  ordinary  Cartilage 


Fig.  10. 


Cells  with  radiating  Fibres,  from 
the  fluid  of  the  vesicles  of  Herpes 
labialis. 


1  "Lectures  on  the  Processes  of  Repair  and  Reproduction  after  Injuries,"  in  "Medical 
Gazette,"  1849,  vol.  xliii.  p.  1071. 

2  "  Second  Series  of  Experimental  Researches  on  the  Process  of  Nutrition  in  the  Living 
Structure,"  p.  5  ;  and  "Third  Series,"  p.  7. 


OF  SIMPLE  MEMBRANE;  ITS  FORMATION  AND  PROPERTIES.     139 

(Fig.  51)  and  a  distinct  fibrous  tissue  (Fig.  52).  Here,  too,  it  is  possible  that, 
although  the  fibres  do  not  themselves  originate  in  the  transformation  of  cells, 
the  cells  of  the  cartilage  may  exert  such  a  determining  agency  in  their  produc- 
tion, as  appears  to  proceed  from  the  nuclei  in  the  cases  previously  referred  to. — 
Of  all  the  varieties  of  Fibrous  tissue  thus  generated,  it  may  be  stated  that  their 
function  is  simply  mechanical ;  that  consequently  the  performance  of  that  func- 
tion does  not  depend  upon  a  continuance  of  vital  activity;  and  that  they  do  not 
seem  to  possess  that  power  of  self-formation  which  is  characteristic  of  the  cellular 
tissues,  but  for  the  most  part  depend,  for  their  production,  the  maintenance,  and 
regeneration  after  injury,  upon  the  formative  power  of  the  Blood  (§  224). 

119.  Of  Simple  Membrane;  its  Formation  and  Properties. — In  many  parts 
of  the  Animal  body,  we  meet  with  membranous  expansions  of  extreme  delicacy 
and  transparency,  in  which  no  definite  structure  can  be  discovered ;  and  these 
seem,  like  the  simple  fibres  just  described,  to  have  been  formed  rather  directly 
from  the  nutritive  fluid,  than  indirectly  by  any  process  of  transformation.  The 
characters  of  this  kind  of  membrane  were  first  pointed  out  by  Mr.  Bowman1 
and  Prof.  Goodsir;2  by  the  former  of  whom  it  was  named  &ase?we7^-membrane, 
as  being  the  foundation  or  resting-place  for  the  epithelial  or  epidermic  cells 
which  usually  lie  upon  its  free  surface ;  whilst  by  the  latter  it  was  termed  the 
primary  or  germinal  membrane,  as  furnishing  (in  his  opinion)  the  germs  of 
those  cells.  In  its  very  simplest  form,  the  basement-membrane  is  a  pellicle  of 
such  extreme  delicacy,  that  its  thickness  scarcely  admits  of  being  measured ;  it 
is  to  all  appearance  perfectly  homogeneous,  and  presents  not  the  slightest  trace 
of  structure  under  the  highest  powers  of  the  microscope,  appearing  like  a  thin 
film  of  coagulated  gelatine.  Examples  of  this  kind  may  easily  be  procured,  by 
acting  on  the  inner  layer  of  any  bivalve  shell  with  dilute  acid ;  this  dissolves 
away  the  calcareous  matter,  and  leaves  the  basement-membrane.  In  other  cases, 
however,  the  membrane  is  not  so  homogeneous ;  a  number  of  minute  granules 
being  scattered,  with  more  or  less  of  uniformity,  through  the  transparent  sub- 
stance. And  we  not  unfrequently  find,  in  the  place  of  these  uniformly  dis- 
tributed granules,  a  series  of  distinct  spots,  arranged  at  equal  or  variable  dis- 
tances, and  lying  in  different  directions ;  of  this  Prof.  Goodsir  has  adduced  a 
good  example  in  the  membrane  of  the  intra-glandular  lymphatics.3  Moreover, 
the  membrane  thus  constituted  is  disposed  to  break  up  into  portions  of  equal 
size,  each  of  which  contains  one  of  these  spots ;  whilst  in  the  more  homogeneous 
forms  previously  described,  no  appearance  of  any  definite  arrangement  is  per- 
ceptible when  they  are  torn.  Hence  it  would  seem  as  if  the  first  and  simplest 
form  were  produced  by  the  simple  consolidation  of  a  thin  layer  of  homogeneous 
fluid  ]  the  second  by  a  layer  of  such  fluid,  including  nuclear  particles ;  and  the 
third  by  the  coalescence  of  flattened  cells,  whose  further  development  has  been 
checked,  but  whose  nuclei  may  still  continue %  to  perform  their  characteristic 
functions.  It  is  probable  that  the  primary  membrane  exists,  under  one  or 
other  of  these  forms,  on  all  the  free  surfaces  of  the  body ;  though  it  cannot 
be  everywhere  demonstrated.  Thus  it  appears  to  constitute  ^the  outer  layer  of 
the  true  Skin,  lying  between  its  fibrous  substance  and  the  epidermis ;  it  lines 
all  the  cavities  formed  by  Mucous  membranes,  and  is  prolonged  into  all  the 
ducts  and  ultimate  follicles  and  tubuli  of  Glands  which  are  connected  with  them, 
being,  indeed,  with  the  exception  of  the  epithelial  cells  which  cover  its  inner  sur- 
face, the  sole  constituent  of  some  of  these ;  it  forms  the  innermost  layer,  also, 
of  the  Serous  and  Synovial  membranes,  there,  also,  supporting  the  epithelium ; 

1  See  his  memoir  "On  the  Structure  and  Uses  of  the  Malpighian  Bodies  of  the  Kidney" 
in  the  "Philos.  Transact.,"  1842;  and  the  "Cyclopedia  of  Anatomy  and  Physiology," 
vol.  iii.,  Art.  "Mucous  Membrane." 

2  "Anatomical  and  Pathological  Observations,"  p.  3. 

3  "Anatomical  and  Physiological  Observations,"  pp.  46,  47. 


140         OF   THE   STRUCTURAL   ELEMENTS   OF   THE   HUMAN   BODY. 

and  it  lines  the  bloodvessels  and  lymphatics,  forming  the  sole  constituent  of 
the  walls  of  their  minutest  divisions.  In  all  these  cases,  its  function  appears  to 
be,  in  part  at  least,  the  limitation  of  the  too  free  transudation  of  fluid ;  a  sufficient 
amount  being  allowed  to  pass,  however,  for  the  wants  of  the  tissues  which  it  cuts 
off  from  direct  relation  with  the  blood.  Thus,  the  epidermic  and  epithelial  cells 
of  the  skin,  mucous  membranes,  &c.,  draw  their  nourishment,  through  the  base- 
ment-membrane on  which  they  rest,  from  the  vessels  of  the  subjacent  tissue; 
just  as  the  tissues  which  are  themselves  permeated  by  capillary  vessels  can  only 
draw  nutrient  materials  from  the  interior  of  the  latter  through  the  membrane 
which  constitutes  their  walls.  But  it  seems  probable  that  this  membrane  usually 
performs  a  much  more  important  office  than  that  of  simply  limiting  the  fluids, 
whilst  allowing  the  requisite  degree  of  transudation ;  for  there  is  strong  reason 
to  believe  that  it  has  an  important  instrumentality  in  the  production  of  the  cells 
which  are  continually  originating  on  its  surface,  either  by  itself  furnishing  their 
germs,  or  (in  the  case  of  the  epidermis)  by  promoting  the  development  of  cells 
de  novo  in  the  organizable  blastema  which  lies  beneath  its  deepest  layers.  The 
mode  in  which  these  cells  originate,  however,  will  become  the  subject  of  dis- 
cussion hereafter  (CHAP.  v.  SECT.  2). 

2.    Of  Vital  force,  and  the  Conditions  of  its  Exercise. 

120.  When  we  pass  from  the  mere  observation  of  the  elementary  phenomena 
of  Life,  described  in  the  previous  section,  to  the  search  for  their  causes,  we  find 
that,  as  in  other  cases,  the  conditions  of  all  Vital  changes  are  twofold,  namely, 
material  and  dynamical  (INTRODUCTION,  p.  35);  the  former  consisting  in  the 
due  supply  of  the  appropriate  pabulum  for  the  development  of  organic  structure ; 
the  latter,  in  the  exercise  of  a  force  or  power  whereby  this  is  organized  and  vital- 
ized. The  Animal  cell  cannot,  like  that  of  the  Plant,  generate  its  pabulum  for 
itself  out  of  the  inorganic  elements  around  it ;  but  is  dependent  upon  that  which 
has  been  prepared  for  it;  and  in  Man,  as  in  all  the  higher  forms  of  Animal  ex- 
istence, this  pabulum  is  furnished  to  each  growing  part  by  the  circulating  fluid, 
which  has  been  prepared  by  previous  operations.  It  is  the  essential  character 
of  this  fluid,  that  it  contains  the  materials  ready  to  be  appropriated  by  the  walls 
and  nuclei  of  cells,  which  are  probably,  as  we  have  seen,  of  uniform  composition ; 
and  the  material  of  the  simple  fibres  and  membranes,  also,  is  yielded  by  the 
essential  components  of  the  blood,  in  a  state  in  which  it  seems  readily  to  undergo 
the  requisite  transformation.  The  contents  of  the  various  groups  of  cells  form- 
ing part  of  the  organism  are,  however,  extremely  varied;  and  no  particular 
order  of  these  can  be  generated,  unless  the  nutritive  fluid  contain  the  materials 
for  them,  either  ready  formed,  or  in  a  state  in  which  the  cell  itself  can  produce 
them  by  a  process  of  chemical  transformation.  Thus,  Adipose  tissue  cannot  be 
formed,  unless  there  be  fatty  matter  in  the  blood ;  the  Red  Corpuscles  cannot 
be  produced  without  a  supply  of  iron;  the  Secreting  cells  of  the  Kidney  require 
for  their  development  a  supply  of  urinary  matter ; — and  so  on.  But  further, 
there  is  evidence  that  the  presence  of  a  particular  substance  in  the  nutritive  fluid 
determines  the  development  of  the  particular  kind  of  cell  of  which  it  is  the 
appropriate  pabulum,  provided  that  the  other  requisite  conditions  are  supplied. 
Thus,  an  increase  of  Adipose  tissue  takes  place,  when  the  blood  habitually  con- 
tains an  unusual  amount  of  fat;  an  augmentation  in  the  proportion  of  the  Red 
Corpuscles  of  the  blood  may  be  distinctly  observed  (especially  if  they  have  been 
previously  diminished  unduly),  when  an  additional  supply  of  iron  is  afforded 
(§174);  and  when  one  of  the  kidneys  has  been  removed,  or  is  prevented  by 
disease  from  performing  its  normal  duty,  the  other,  if  it  remain  healthy,  under- 
goes an  extraordinary  increase  in  size,  so  as  to  perform  the  duty  of  both  organs, 
the  augmented  development  of  its  secreting  structure  being  here  also  fairly 


OF   VITAL   FORCE,    AND   THE   CONDITIONS   OF   ITS   EXERCISE.      141 

attributable  to  the  accumulation  of  its  appropriate  materials  in  the  blood.  This 
principle  is  one  most  fertile  in  Pathological  applications;  for  there  can  be  little 
doubt  that  the  development  of  many  morbid  growths  is  due,  not  so  much  to  a 
perverted  local  action,  as  to  the  presence  of  certain  morbid  matters  in  the  blood, 
which  determine  the  formation  of  tissues  that  use  them  as  their  appropriate 
pabulum.  Such  is  pretty  obviously  the  case  with  those  disorders  which  (like 
the  Exanthemata)  are  universally  admitted  to  be  of  "  constitutional"  character, 
and  which  are  distinctly  traceable  to  a  poison  introduced  through  the  blood,  whose 
first  influence  is  exerted  in  modifying  the  physical  and  vital  properties  of  that 
fluid ;  and  the  evidence  has  been  of  late  accumulating,  that  it  is  true  also  of  the 
various  forms  of  Cancer,  the  local  development  of  an  abnormal  structure  being 
in  this  case,  also,  nothing  else  than  the  manifestation  of  the  existence  of  that 
peculiar  matter  in  the  blood,  which  is  the  appropriate  nutriment  of  its  compo- 
nent tissues — or,  as  Mr.  Simon  appropriately  designates  it,  "a  new  excretory 
organ,  which  tends  essentially  to  acts  of  eliminative  secretion,  just  as  distinctly 
as  the  healthy  liver  or  the  healthy  kidney."1 

121.  But  however  abundant  may  be  the  supply  of  the  nutritive  materials,  and 
however  complete  may  be  their  preparedness  for  organization,  they  can  no  more 
become  organized  into  cells  by  their  own  powers,  than  a  mass  of  iron  could  shape 
itself  into  a  steam-engine  or  a  spinning-jenny.     They  need  to  be  acted  on  by 
the  appropriate  force  ;  and  this  we  have  seen  to  be,  in  the  first  place,  the  vital 
power  of  a  pre-existing  organism.     For  whether  new  cells  are  formed  by  the 
subdivision  of  previous  cells,  or  sprout  from  the  granules  of  their  nuclei  (either 
within  the  parent-cell,  or  after  being  set  free  from  it),  or  originate  in  an  organi- 
zable  blastema,  we  trace  that  influence  everywhere  exerted.     When  the  cell 
reaches  a  certain  stage  of  its  development,  however,  it  becomes  self-dependent ; 
being  capable  of  maintaining  its  own  life,  if  the  material  conditions  be  supplied, 
without  the  assistance  of  vital  force  imparted  to  it  from  without;  and  in  its  turn, 
it  comes  to  impart  a  similar  power  to  the  germs  which  it  may  itself  prepare,  or 
to  the  plastic  fluid  which  it  may  assist  in  elaborating. 

122.  But  the  question  next  arises,  what  is  the  original  source  of  that  Organiz- 
ing force,  which  the  cell  receives  during  the  early  stage  of  its  development,  and 
which  it  subsequently  itself  exerts  upon  the  nutrient  matter  it  appropriates  ? 
And  to  this  question  it  seems  now  possible  to  give  a  more  satisfactory  answer 
than  that  with  which  Physiologists  were  formerly  obliged  to  satisfy  themselves. 
For  it  was  maintained  by  some,  that  the  germ  of  every  living  being  contains 
within  itself  the  whole  of  the  force  necessary  to  accomplish  the  organization  of 
its  fabric,  and  to  impart  to  each  portion  of  it  the  peculiar  powers  with  which  it 
is  endowed;  an  obvious  objection  to  which  doctrine  is,  that,  if  this  be  true,  not 
only  must  the  germ  contain  the  whole  vital  force  of  the  fabric  into  which  it  is 
evolved,  but  also  that  which  it  imparts  to  its  descendants ;  so  that  the  first  indi- 
vidual of  a  race  must  have  concentrated  within  itself  the  vital  force  of  its  entire 
posterity — a  palpable  reductio  ad  absurd  um.     To  escape  from  this  difficulty,  it 
has  been  alleged  that  the  vital  force  with  which  matter  becomes  endowed  by  the 
process  of  organization,  previously  existed  in  it  in  a  latent  or  dormant  state,  and 
is  made  sensible  when  the  nutrient  matter  is  incorporated  into  a  living  fabric. 
This  doctrine  could  claim  no  higher  value  than  that  of  a  mere  hypothesis;  and 
it  rested  on  the  idea  that  latent  or  dormant  force  of  other  kinds   (such  as 
Heat)  had  a  real  existence — an  idea  of  which  a  more  logical  appreciation  of  the 
facts  of  science  has  completely  exposed  the  fallacy.     For  it  is  now  coming  to  be 
generally  acknowledged,  that  all  force  must  (from  its  very  nature)  be  active  in 
some  mode  or  other;  that  force  can  neither  originate  de  novo,  nor  cease  to  be 

1  See  Mr.  Simon's  " Lectures  on  General  Pathology,"  pp.  87,  152;  and  Mr.  Paget's 
"Lectures  on  Inflammation,"  in  "Medical  Gazette,"  1851,  vol.  xlv.  p.  92.  % 


142         OF   THE   STRUCTURAL   ELEMENTS   OF   THE   HUMAN   BODY. 

operative  under  some  form ;  and  that  in  every  case  in  which  force  seems  to  be 
annihilated,  it  merely  changes  its  modus  operandi.  Thus,  when  Motion  is 
retarded  by  friction,  Heat  is  generated,  with  Electricity  in  addition  whenever 
the  rubbing  surfaces  are  otherwise  than  perfectly  homogeneous ;  so  when  Heat 
is  caused  to  vaporize  water,  it  no  longer  manifests  itself  as  Heat,  but  in  the 
form  of  mechanical  power  which  produces  Motion ;  and  the  discharge  which 
restores  the  Electric  equilibrium  is  in  like  manner  attended  with  the  develop- 
ment of  Mechanical  force.1  It  will  be  found  that,  in  all  instances  in  which  such 
a  conversion  or  metamorphosis  of  force  takes  place,  some  material  substratum  is 
required  as  its  instrument.  This  may  be,  in  some  cases,  of  almost  any  descrip- 
tion whatever ;  as  when  Heat  is  produced  by  the  friction  (or  retarded  motion) 
of  solids,  liquids,  or  even  gases ;  or  when  Motion  (as  shown  in  expansion)  is 
produced  by  the  application  of  heat  to  any  kind  of  material  substance.  But  in 
other  cases,  the  change  can  only  be  effected  through  some  special  kind  of  instru- 
ment ;  or,  if  several  substances  may  serve  as  its  medium,  there  is  some  one 
which  is  greatly  superior  to  every  other,  in  the  readiness  with  which  a  certain 
force  manifests  itself  through  it.  Thus,  iron  is  the  substance  through  which  an 
Electric  current  can  best  develop  Magnetic  force ;  a  combination  of  bismuth  and 
antimony  is  that  through  which  Heat  can  best  generate  Electricity ;  and  the 
affection  of  Light  by  Magnetism,  though  producible  through  any  transparent 
medium  (but  not  through  a  vacuum),  can  be  made  much  more  obvious  when 
the  magnetism  is  made  to  act  upon  a  glass  composed  of  vitrified  borate  of  lead, 
than  through  the  medium  of  any  other  substance  yet  known.  It  is,  indeed,  on 
this  speciality  in  the  action  of  different  substances,  when  subjected  to  the  influ- 

1  [The  doctrine  of  the  correlation  of  the  Physical  forces  here  alluded  to  has  never  as 
yet,  we  believe,  been  accredited  to  its  true  source.  The  treatise  of  Prof.  Grove  on  the 
Correlation  of  the  Physical  Forces  is  usually  regarded  as  the  first  publication  on  this  sub- 
ject. It  is  dated  1843.  This  was  followed  by  that  of  Dr.  J.  R.  Mayer,  dated  Heilbronn, 
1845.  Subsequently  there  have  appeared  the  author's  memoir  on  the  "  Mutual  Relations 
of  the  Physical  and  Vital  Forces,"  in  1850;  and  Mr.  Newport's  paper  "On  the  Reciprocal 
Relation  of  the  Vital  and  Physical  Forces,"  1850.  In  anticipation  of  all  these,  however, 
the  doctrine  was  formally  enunciated  from  the  chair  of  "Institutes  of  Medicine"  by  Prof. 
Jackson  of  the  University  of  Pennsylvania,  as  early  as  the  year  1837,  as  will  be  seen  by 
the  following  extract  from  an  introductory  lecture  delivered  and  published  at  that  time. 
"Physical  phenomena,  according  to  the  class  they  belong  to,  are  referred  to  a  few  simple 
laws,  as  gravity,  caloric,  affinity,  galvanism,  electricity,  magnetism ;  all  of  which,  it  can 
now  be  scarcely  doubted,  are  modifications  of  one  great  force.  The  force  producing  phy- 
siological or  organic  phenomena  may  be  no  more  than  a  modification  of  the  same  ruling 
power  displaying  its  activity  in  organized  matter.  Movements,  the  influence  or  powers 
that  cause  them,  the  directions  they  assume  from  the  combined  influence  of  powers  and 
resistances,  intrinsic  or  external,  when  studied  in  inorganic  bodies,  constitute  physics; 
and  in  organized  bodies,  physiology,  or,  as  it  may  be  more  aptly  named,  organic  physics" ' 

The  explanation  of  many  of  the  phenomena  of  living  beings,  hitherto  regarded  as  vital 
phenomena,  upon  chemical  and  physical  principles,  has  been  taught  by  Prof.  Jackson  for 
the  last  eight  years,  and  a  large  portion  of  his  course  has  been  devoted  to  the  classification 
and  arrangement  of  them  into  the  separate  classes  to  which  they  belong ;  thus,  the  pro- 
duction of  the  immediate  materials  of  organic  tissue  by  a  transformation  of  albumen,  di- 
gestion, calorification,  and  secretion,  are  classed  as  chemical  actions ;  absorption,  endos- 
mose,  -muscular  electricity,  vision,  hearing,  voice,  belong  to  physics.  The  spinal  functions 
are  purely  dynamic ;  the  muscular  functions  are  mechanical.  The  principles  of  mechanics 
are  applicable  to  the  explanation  of  the  circulation — a  hydraulic  apparatus ;  to  locomotion, 
general  or  partial ;  and  to  the  operation  of  ingestion  and  egestion. 

In  the  second  edition  of  Prof.  Grove's  treatise  on  the  "  Correlation  of  Forces,"  published 
in  1850,  the  following  remarks  occur:  "I  believe  that  the  same  principle  and  mode  of 
reasoning  as  have  been  adopted  in  this  essay,  might  be  applied  to  the  organic,  as  well  as 
to  the  inorganic  world;  and  that  muscular  force,  animal  and  vegetable  heat,  &c.,  might, 
and  at  some  time  will,  be  shown  to  have  similar  definite  correlation."  The  correlation 
between  the  mechanical  force  of  the  muscular  system  and  heat  was  announced  in  a  paper 
read  by  Prof.  Jackson  before 'the  American  Medical  Association  in  1849,  and  published  in 
their  '••Transactions"  for  the  year  1849. — Ed.~\ 


OF   VITAL   FORCE,    AND   THE   CONDITIONS   OF  ITS   EXERCISE. 


143 


ence  of  the  same  forces,  that  our  notion  of  their  properties  entirely  rests ;  and 
to  say  that  all  matter  which  is  capable  of  becoming  organized  possesses  "vital 
properties/'  is  merely  to  affirm,  in  other  words,  that  it  is  capable  of  being  made 
a  part  of  a  living  structure,  and  of  -becoming  the  instrument  of  operating  after 
the  same  fashion  upon  other  matter — leaving  the  question  as  to  the  source  or 
origin  of  the  force  which  thus  changes  it,  or  by  which  it  induces  changes  in  other 
matter,  just  where  it  was. 

123.  The  doctrines  which  have  been  just  now  glanced  at,  as  expressing  the 
present  aspect  of  Physical  Science,  whilst  they  indicate  the  fallacy  of  some  of 
what  have  been  considered  the  established  principles  of  Physiology,  conduct  us 
at  the  same  time  to  a  new  and  more  satisfactory  solution  of  the  problem.  Look- 
ing at  the  phenomena  of  Life  from  the  same  point  of  view  as  that  from  which 
we  are  now  taught  to  regard  those  of  Physical  Science — namely,  as  the  results 
or  manifestations  of  a  certain  kind  of  force,  acting  through  those  forms  of  matter 
which  we  term  organized — we  are  further  led  to  seek  for  its  source,  not  in  the 
organism  itself,  but  in  some  power  external  to  it.  And  this  power  we  find  in 
those  Physical  agencies,  Light,  Heat,  and  Electricity,  which  have  been  com- 
monly accounted  "Vital  Stimuli/'  their  operation,  either  singly  or  in  combina- 
tion, having  long  been  recognized  as  necessary  to  enable  an  organized  structure 
to  manifest  vital  phenomena.  Thus,  Light,  acting  upon  the  living  Vegetable 
cell,  makes  it  the  instrument  of  decomposing  carbonic  acid,  water,  and  ammonia, 
and  of  generating  organic  compounds  which  the  Chemist  has  not  yet  been  able 
to  imitate ;  and  the  amount  of  carbonic  acid  thus  decomposed  has  been  found  to 
bear  a  constant  ratio  (cseteris  paribus)  to  the  illuminating  power  of  the  rays 
which  it  receives.1  The  agency  of  light,  however,  is  chiefly  exerted  in  prepar- 
ing the  pabulum  to  be  appropriated  by  the  organism ;  and  we  see,  in  the  germi- 
nating seed,  that  where  this  has  been  previously  ela-borated,  light  is  not  required 
for  its  conversion  into  living  tissue.  But  for  this  purpose,  a  certain  measure  of 
Heat  is  required;  and  the  rate  of  germination,  that  is,  the  rate  at  which  the 
organizable  material  is  converted  into  living  tissue,  is  determined  (within  certain 
limits)  by  the  degree  in  which  that  agent  is  in  operation.  In  the  Animal  king- 
dom, for  which,  as  for  the  germinating  seed,  the  nutrient  material  is  already 
provided  by  a  pre-existing  vegetation,  the  dynamical  influence  of  Light  is  of 
comparatively  little  importance;  but  we  have  abundant  evidence,  in  the  life  of 
the  "cold-blooded"  tribes,  which  are  destitute  of  the  power  of  maintaining  an 
independent  temperature,  that  the  rate  of  vital  activity,  as  manifested  both  in 
the  phenomena  of  growth  and  development,  and  in  the  production  of  nervo- 
muscular  force,  is  determined  (within  certain  limits)  by  the  amount  of  Heat 
to  which  the  individual  is  subjected.  This  dependence  is  no  less  real  and 
immediate  in  the  case  of  warm-blooded  animals ;  but  it  is  rendered  less  apparent 
by  the  uniformity  of  temperature  which  they  are  enabled  to  sustain.  Of  the 
degree  in  which  the  ordinary  phenomena  of  Life  are  dependent  upon  Electricity 
acting  upon  the  organism  from  without,  we  as  yet  know  next  to  nothing ;  the 
mode  in  which  they  are  affected  by  this  agent  not  having  been  yet  precisely 
determined.  It  can  scarcely  be  doubted,  however,  from  what  is  known,  that  it 
stands  in  very  close  relation  to  Vital  force,  and  is  capable  of  exerting  an  ex- 
tremely powerful  influence  upon  its  operations. 

124.  It  seems,  then,  to  be  a  legitimate  expression  of  the  dynamical  conditions 
requisite  for  the  production  of  the  phenomena  which  we  distinguish  as  Vital,  to 
say  that  they  are  dependent,  directly  or  indirectly,  upon  the  Physical  forces 
pervading  the  Universe;  which,  acting  through  organized  structure  as  their 
"  material  substratum/'  manifest  themselves  as  Vital  Force,  one  of  the  most 
characteristic  operations  of  this  being  the  production  of  new  tissue,  which  in  its 

1  See  Prof.  Draper  "  on  the  Forces  which  produce  the  Organization  of  Plants,"  p.  177. 


144         OF   THE    STRUCTURAL   ELEMENTS   OF   THE   HUMAN   BODY. 

turn  may  become  the  instrument  of  a  similar  metamorphosis.  And  we  have 
the  same  kind  of  evidence,  that  Light  and  Heat,  acting  upon  the  organic  germ, 
become  transformed  into  Vital  force,  which  we  possess  of  the  conversion  of  Heat 
into  Electricity  by  acting  on  a  certain  combination  of  Metals,  or  of  Electricity 
into  Magnetism  by  being  passed  round  a  bar  of  iron,  or  of  Heat  or  Electricity 
into  Motion  when  their  self-repulsive  action  separates  the  particles  of  matter 
from  each  other.  For  we  shall  presently  find,  that  just  as  Heat,  Light,  Chemi- 
cal Affinity,  &c.,  are  transformable  into  Vital  force,  so  is  Vital  force  capable  of 
manifesting  itself  in  the  production  of  Light,  Heat,  Electricity,  Chemical  Affinity, 
or  Mechanical  Motion ;  thus  completing  the  proof  of  that  mutual  relationship, 
or  "  correlation, "  which  has  been  shown  to  exist  among  the  Physical  and  Che- 
mical forces  themselves. 

125.  In  order,  however,  to  arrive  at  a  definite  and  complete  conception  of  the 
source  of  Vital  force  in  the  Human  Organism,  it  will  be  necessary  to  examine, 
a  little  more  in  detail,  into  the  reciprocal  relations,  material  and  dynamical, 
which  subsist  between  the  Animal  and  Vegetable  kingdoms,  and  between  these 
and  the  Inorganic  world. — The  Plant,  when  acted  on  by  Light,  forms  certain 
organic  compounds,  at  the  expense  of  the  water,  carbonic  acid,  and  ammonia, 
of  the  soil  and  atmosphere,  decomposing  these  binary  compounds  into  their  four 
elements,  and  uniting  these  again  into  ternary  and  quaternary  combinations  of 
a  very  peculiar  character }  and  the  Light,  by  whose  agency  alone  this  process 
can  be  effected,  may  be  considered  as  metamorphosed  into  the  peculiar  affinity, 
or  chemical  force,  by  which  the  elements  of  these  compounds  are  held  together.1 
The  pabulum  thus  generated  is  applied  by  the  Vegetable  organism  to  the  exten- 
sion of  its  own  structure,  the  vital  force  requisite  for  this  purpose  being  sus- 
tained by  Heat  acting  ab  externo ;  and  thus  the  fabric  may  be  augmented  to  an 
almost  unlimited  extent,  every  increase  of  surface  affording  a  new  instrument 
for  the  agency  of  light,  and  thus  affording  the  conditions  requisite  for  the  pro- 
duction of  an  additional  amount  of  organic  compounds.  The  whole  nisus  of 
vegetable  life  may  be  considered  as  manifesting  itself  in  this  production ;  and, 
in  effecting  it,  each  organism  is  not  only  drawing  material,  but  force  from  the 
universe  around  it.  Supposing  that  no  Animals  existed  to  consume  these  or- 
ganic compounds,  they  would  be  all  at  last  restored  back  to  the  inorganic  con- 
dition by  spontaneous  decay,  which  would  reproduce  the  water,  carbonic  acid, 
and  ammonia,  from  which  they  were  at  first  generated.  In  this  decay,  how- 
ver  slow,  light  and  heat  would  be  given  out,  in  the  same  amount  as  when  more 
evidently  produced  in  the  ordinary  combustive  process ;  and  we  do  in  fact  ob- 
serve, that,  during  certain  phases  of  vegetation  (namely,  germination  and  flow- 
ering) a  sensible  amount  of  Heat  is  produced  by  many  plants  as  one  of  the 
ordinary  phenomena  of  their  lives,  Light  also  being  occasionally  manifested.3 
Moreover,  spontaneous  movements  are  sometimes  to  be  observed  in  Plants, 
under  circumstances  which  indicate  that  they  are  to  be  considered  as  manifesta- 
tions or  expressions  of  Vital  force;  and  thus  the  Vegetable,  even  during  its 
life,  may  restore  to  the  Universe  some  portion  of  the  forces  which  it  has  derived 
from  it  under  other  forms.  It  is  only,  however,  when  the  complete  conversion 
of  the  organic  compounds  it  has  formed,  into  the  binary  compounds  which  fur- 
nished their  materials,  has  taken  place,  that  the  Plant  can  be  considered  as  hav- 
ing wholly  given  back  the  forces  which  it  consumed  in  their  first  production; 
and  this  period  may  be  also  indefinitely  postpoaed  by  the  preservation  of  these 
substances ;  so  that  in  fact  it  is  only  now,  that  Man,  whilst  consuming  the 

1  That  Light,  or  some  component  of  it,  ceases  to  exist  as  such,  when  it  thus  operates 
upon  living  Vegetable  surfaces,  is  shown  by  the  curious  fact  that  such  surfaces  are  al- 
ways represented  in  Photographic  pictures  as  if  they  were  black,  that  is,  as  if  they  received 
or  reflected  no  light  at  all. 

2  See  "Prin.  of  Phys.,  Gen.  and  Comp.,"  \\  607,  616,  Am.  Ed. 


OF   VITAL   FORCE,    AND   THE   CONDITIONS   OF   ITS   EXERCISE.      145 

stores  of  Coal  which  have  been  prepared  for  his  use  by  the  luxuriant  Flora  of 
past  ages,  is  reproducing  and  applying  to  his  own  purposes  the  Light  and  Heat 
which  sustained  the  vegetable  life  of  the  Carboniferous  period,  whilst  returning 
to  the  atmosphere  the  water,  carbonic  acid,  and  ammonia,  which  were  then 
withdrawn  from  it. 

126.  But  the  Organic  Compounds  which  the  agency  of  Light  and  Heat  upon 
the  Vegetable  fabric  has  produced,  are  designed  for  a  much  higher  purpose  than 
that  of  being  merely  given  back  to  the  Inorganic  universe  by  decay  or  combus- 
tion; and  the  forces  which  hold  together  their  elements  have  a  much  more  ex- 
alted destiny.     In  serving  as  the  food  of  Animals,  a  part  of  these  compounds 
become  the  materials  of  their  organized  tissues,  and  the  instruments  by  which 
their  various  forms  of  Vital  power  are  exercised;  and  in  the  greater  number  of 
Animals,  as  in  the  germinating  seed,  the  Heat  which  is  supplied  from  without 
may  be  looked  upon  as  the  ultimate  source  of  the  power  by  which  the  organ- 
izing process  is  carried  on.     Thus,  during  the  whole  period  of  growth  and  de- 
velopment, there  is,  as  in  the  Plant,  a  continual  augmentation  in  the  amount  of 
Vital  action  performed ;  and  the  increase  of  this  would  be  unlimited,  were  it 
not  checked  by  a  process  of  a  converse  character.     For  the  peculiar  activity  of 
Animals  consists,  not  in  the  phenomena  of  vegetative  growth,  but, in  the  per- 
formance of  movements,  through  the  instrumentality  of  the  nervo-muscular 
apparatus,  which  is  built  up  by  the  organizing  process;  and  the  execution  of 
these  movements  involves  an  expenditure  of  Vital  force,  as  manifested  in  the 
death  and  disintegration  of  the  nervo-muscular  tissues,  which  appears  to  be  in 
strict  relation  to  the  amount  of  Physical  power  thus  generated.     And  thus  it 
happens,  that  there  is,  during  Animal  life,  a  continual  restoration  to  the  Inor- 
ganic world,  of  the  water,  carbonic  acid,  and  ammonia,  originally  supplied  by  it 
as  the  food  of  plants ;  these  being  formed  by  the  union  of  the  oxygen  of  the 
atmosphere  (which  was  not  appropriated  by  the  plant)  with  the  elements  of  the 
nervo-muscular  tissue,  or  rather  with  those  of  urea,  lactic  acid,  &c.,  which  are 
the  immediate  products  of  their  decay  (§  91).     Not  only  is  Motion  thus  gene- 
rated, but  also  Heat,  and  (occasionally)  Light  and  Electricity;  and  thus  an 
Animal  which  has  arrived  at  its  full  growth,  and  which  is  simply  maintaining 
the  standard  it  has  then  acquired,  is  continually  restoring  to  the  Inorganic 
world  both  the  material  equivalents  of  its  food,  and  the  dynamical  equivalents 
of  the  Chemical  affinities  which  held  together  the  elements  of  this,  as  well  as 
of  the  Heat  which  supplied  the  organizing  force  whereby  it  was  converted  into 
living  tissue.     The  final  decay  of  the  organism,  as  in  the  Plant,  will  give  back 
both  the  material  and  dynamical  equivalents  of  the  matter  and  force  which  were 
consumed  in  its  first  production,  unless  its  substance  should  be  appropriated  as 
food  by  another  organism ;  in  which  case  it  serves  to  the   Carnivorous  animal 
precisely  the  same  purposes,  as  those  to  which  the  organic  compounds  supplied 
by  the  Plant  are  subservient  in  the  Herbivorous  animal. 

127.  The  condition  of  Man  and  of  all  "  warm-blooded"  animals,  however, 
differs  in  this  important  particular  from  that  of  "  cold-blooded"  animals,  and  of 
plants.     For,  whilst  the  latter  are  almost  entirely  dependent  for  the  Heat  which 
is  the  source  of  their  vital  force,  upon  that  which  they  receive  from  the  solar 
rays,  so  that  their  temperature  rises  and  falls  with  that  of  the  medium  they  in- 
habit, the  former  are  enabled  to  maintain  the  heat  of  their  bodies  at  a  constant 
standard,  by  combustive  processes  which  take  place  in  their  interior,  at  the  ex- 
pense, not  only  of  the  materials  of  their  disintegrated  tissues,  but  also  of  a  por- 
tion of  their  food,  the  non-azotized  ingredients  of  which  are  chiefly  appropriated 
to  this  purpose  (§§  42,  50).     And  thus  we  find  that  whilst  the  Azotized  com- 
pounds prepared  by  Plants  supply  the  actual  materials   for  the  building-up  of 
the  Animal  fabric,  the  Hydro-carbonaceous  or  non-azotized  (starchy,  saccharine, 
oleaginous,  &c.),  answer  the  not  less  important  purpose  of  furnishing,  by  their 

10 


146         OF   THE    STRUCTURAL   ELEMENTS   OF    THE    HUMAN   BODY. 

restoration  to  their  original  condition,  the  chief  dynamical  agency,  which,  act- 
ing through  the  previously-formed  organic  structure,  enables  it  to  appropriate 
the  former,  and  thus  to  supply  the  conditions  needed  for  the  production  of  nervo- 
muscular  power,  the  development  of  which  may  be  considered  as  the  great  end 
and  aim  of  Animal  existence.  And  it  is  a  very  interesting  exemplification  of 
the  correctness  of  these  views,  that  the  rate  of  recurrence  of  those  "periodical 
phenomena"  of  various  kinds,  which  mark  the  progress  of  vital  activity,  should 
be  almost  entirely  dependent  among  cold-blooded  animals  upon  external  influ- 
ences, so  that  they  may  be  artificially  accelerated  by  warmth  and  retarded  by  cold ; 
whereas,  in  warm-blooded  animals,  their  recurrence  is  far  more  regular,  the  rate 
of  their  vital  activity  being  kept  at  a  much  more  uniform  standard,  in  virtue  of 
their  fixed  temperature.1 

[It  is  questionable  whether  the  views,  so  ingeniously  conceived,  and  which 
here  and  elsewhere9  are  so  ably  expounded,  advance  our  knowledge  of  the  agency 
concerned  in  the  production  of  vital  manifestation ;  whether,  after  all,  we  are  not 
constrained  to  look  beyond  a  "  material  substratum/'  and  the  "  Physical  forces 
pervading  the  universe/'  for  that  unknown  force  which,  out  of  formless  material, 
is  capable  of  evolving  forms.  Is  it  possible  to  regard  the  organic  forms  of  living 
beings,  bearing  the  impress  of  ideas  that  could  originate  only  in  the  profoundest 
wisdom,  as  proceeding  from  a  force  identical  with  chemical  or  physical  forces,  or 
any  mere  material  force  or  a  necessary  result  of  any  material  condition  ? 

Prof.  Jackson  dissents,  in  a  published  lecture,  from  the  views  of  the  author, 
and  contends  for  the  existence  of  a  peculiar  "  organic  or  vital  force  exclusively 
manifested  in  organic  or  living  beings,  the  dominant  principle  of  organic  or 
vital  actions,  and  the  generator  of  typical  organic  forms."  The  essential  cha- 
racteristic of  an  organic  force  is,  that  it  must  be  present  in  every  organized 
being,  and  that  it  shall  participate  in  every  organic  or  life-action.  Growth 
or  nutrition,  and  the  production  of  typical  forms  are  the  only  phenomena 
that  satisfy  these  indispensable  conditions.  Nervous  force  confined  to  animals, 
and  restricted  in  them  to  nervous  organs  and  apparatus,  fails  in  the  attributes 
of  an  organic,  or  life-force.  Every  organic  form  is  a  life  instrument,  or 
mechanism;  and  the  combined  operations  of  those  which  exist  in  a  living 
organism  constitute  the  phenomena  of  its  life.  The  forms  after  which  the 
tissues  and  organs  of  organized  beings  are  constructed,  are  typical,  and  they  are 
the  essential  organic  phenomena  depending  on  Organic  or  Vital  force,  to  which 
nutrition,  or  the  formation  of  special  organizable  materials,  depending  on  chemi- 
cal forces,  is  subservient. 

The  complete  separation  of  typical  organic  form,  and  simple  nutrition  or 
growth,  is  shown  in  polypous  or  fungoid  growths,  in  cancer  growths,  and  in  some 
cases  of  monstrosities.  In  these  instances  there  is  rapid  production  of  organ- 
izable material,  and  of  growth  or  nutrition,  but  the  cause  or  force  developing 
a  typical  form  is  either  quiescent  or  perverted.  There  is  no  organization ;  there 
is  structure,  but  an  entire  absence  of  normal  tissue  and  of  an  organic  type. 

The  special  character  of  Organic,  or  radical  force  of  Life  is  modality,  or  the 
power  of  creating  organic  forms,  the  instruments  and  mechanisms  of  life.  It 
possesses  none  of  the  attributes  of  the  Physical  Forces  in  its  action  and  influ- 
ences. It  has  no  identity  with  them  :  yet  there  is  undoubted  correlation.  But 
correlation  and  intimate  dependency  do  not  constitute  identity  of  nature.  A 
clear  distinction  is  apparent  between  the  force  that  prepares  by  a  chemical  action 

1  See,  on  the  subject  of  the  preceding  Section,  the  Author's  Memoir  "On  the  Mutual 
Relations  of  the  Vital  and  Physical  Forces,"  in  the  "Philosophical  Transactions"  for  1850; 
Mr.  Newport's  paper  "On  the  Reciprocal  Relations  of  the  Vital  and  Physical  Forces,"  in 
the  "Annals  of  Natural  History,"  Nov.  1850;  and  Dr.  J.  R.  Mayer's  Treatise  "Die  organ- 
ische  Bewegung  in  ihrem  Zusemmenhange  met  dem  stoflfwechsel,"  Heilbronn,  1835. 

2  Princ.  of  Gen.  and  Comp.  Phys.,  g  52,  Am.  Ed. 


OF  VITAL   FORCE,    AND   THE   CONDITIONS   OF   ITS  EXERCISE.      147 

the  material  for  constructing  an  organ  or  instrument,  and  the  force  that  forms 
an  ideal  plan  of  the  instrument  or  organ,  and  constructs  it  of  this  material. 

The  phenomena  of  living  beings,  when  the  organism  is  fully  developed,  and 
its  functions  performed  in  all  the  energy  of  life,  cannot  be  accurately  analyzed. 
The  actions  of  a  living  organism  are  so  interwoven  with  each  other ;  they  are 
so  mutually  intermingled  and  sustaining,  that  the  order  of  their  precedence  is 
not  clearly  observable.  But  in  the  hatching  of  an  egg,  or  the  germination  of 
a  seed,  the  development  of  an  organism  can  be  observed  through  all  its  stages. 

An  examination  of  the  organic  materials  from  which  the  tissues  of  the  newly 
formed  chick  are  constituted,  shows  them  to  be  substances  that  had  no  existence 
in  the  original  egg ;  these  transformations  of  albumen,  undeniably  chemical  in 
nature,  take  place  only  at  a  definite  temperature.  Keep  the  egg  at  a  heat  of 
90°,  the  development  will  not  proceed  beyond  the  first  step;  let  the  heat  be 
maintained  at  110°  F.,  and  the  development  is  equally  arrested.  An  exact 
temperature  is  thus  shown,  under  the  germ-force,  to  be  the  excitor  of  the  special 
chemical  actions  that  generate  from  albumen  special  plasmata  for  organic  struc- 
ture. 

But  these  special  chemical  actions  and  the  formations  of  the  specific  plasms 
for  the  different  tissues,  occur  only  in  the  presence  of  germ-force.  The  germ 
in  these  operations  appears  to  act  in  the  mode  designated  by  Berzelius,  as  cat- 
alytic— or  by  the  action  of  presence.  When  a  germ  has  not  been  produced, 
however,  as  in  an  unfecundated  egg,  and  the  egg  be  exposed  to  a  heat  of  98°  to 
100°  F.,  and  to  atmospheric  air,  then,  instead  of  the  transformation  of  albumen 
into  organic  plasma,  and  next  into  organized  structure,  the  ordinary  chemical 
action  of  putrefaction  is  excited,  and  the  products  are  sulphuretted  hydrogen 
and  sulphuret  of  ammonia. 

This  fact  proves  that  germ-force  is  the  determinative  cause  of  the  special 
chemico-organic  action  necessary  to  organization ;  but  there  is  nothing  that  shows 
identity  between  germ-force,  the  radical  and  primary  organic  force,  heat  and 
chemical  force. 

But  the  phenomena  which  most  unquestionably  characterize  Organic  Nature, 
are  the  perpetual  production  of  special  organic  matter,  and  repetitions  in  suc- 
cessive generations  of  the  same  typical  forms,  infinite  in  number  and  variety, 
expressed  in  the  organization  of  living  beings.  Organic  forms  proceed  from  form- 
less plastic  matter  now,  as  at  the  beginning.  But  the  most  striking  and  familiar 
feature  distinguishing  organic  forms,  at  once  mysterious  and  indefinable,  is  the 
permanency  of  the  created  form,  while  the  material  expressing  that  form  is  the 
most  unstable  and  transitory  of  substances.  Two  forces  are  in  constant  antago- 
nism ;  the  organic  typical,  or  modal  force,  creative  and  preservative  of  the  organic 
form;  and  the  chemical  forces  of  the  material  molecules  that  keep  the  sub- 
stances of  the  forms  in  endless  change.  The  force  that  thus  controls  molecular 
actions,  and  impels  them  to  evolve  from  matter  typical  organic  forms,  is  the 
exclusive  attribute  of  Organic  Nature.  It  is  transmitted  from  generation  to 
generation,  and  is  the  endowment  of  the  germ;  Grerm-force  and  Organic  force 
are  identical. 

The  organic,  germ,  or  formative  force  presides  over  the  initial  phenomena  of 
life,  and  preserves  the  integrity  of  the  organs  and  their  functions  in  after  years. 
It  opposes  a  resistance  to  all  disturbing  agents,  and  shows  itself  to  be  the  "vis 
medicatrix  naturae." 

It  is  not  to  be  understood,  however,  that  it  is  self-acting;  it  is  dependent  upon 
exterior  agents  for  power  to  develop  it  into  activity.  Of  this  we  have  an  ex- 
ample in  the  seed,  which,  though  possessed  of  vitality,  or  the  power  of  being 
roused  into  life,  will  never  germinate  unless  supplied  with  materials  of  growth, 
heat,  oxygen  and  water.  If  any  one  of  these  essentials  be  absent,  disease  results ; 
if  all  are  wanting,  death  ensues. 


148         OF   THE    STRUCTURAL   ELEMENTS    OF   THE   HUMAN   BODY. 

The  exposition  given  above  explains  the  grounds  upon  which  Professor  Jackson 
dissents  from  the  opinion  of  the  author,  who  regards  Organic  force  as  identical 
with  the  Physical  forces.  No  one  can  deny  their  correlation ;  but  no  phenomena 
of  the  Physical  forces  have  analogy  or  resemblance  to  the  persistent  maintenance 
of  typical  forms  amidst  the  ceaseless  commotion  of  the  atoms  of  organic  matter 
in  its  eternal  circle  of  decomposition  and  recombination,  the  constant  phenomena 
of  organic  actions.1 

The  same  doctrine  has  also  been  advanced  by  Dr.  Kirkes  in  his  "  Manual 
of  Physiology/'  in  the  elucidation  of  which,  after  describing  the  "  formative 
force"  as  the  "ability  manifested  in  living  bodies  to  form  themselves  out  of 
materials  dissimilar  from  them/'  he  employs  the  following  language  : — 

"  The  property  to  which  is  referred  the  formative  power  of  living  beings  is, 
however,  no  simple  property,  such  as  the  '  attraction'  of  mechanical  science  or 
the  '  affinity'  of  chemistry.  These  manifest  themselves  in  acts  so  simple  and 
almost  uniform,  that  the  hypothesis  which  assumes  the  existence  of  such  pro- 
perties, supplies  at  once  the  language  in  which  their  laws  of  action  may  be 
enunciated.  But  in  the  simplest  exercise  of  living  formative  power,  even  in 
that  which  accomplishes  the  formation  of  a  cell,  there  is  evidence  of  the  opera- 
tion of  many  forces;  mechanical  force  is  shown  in  the  determination  of  the  po- 
sition, shape,  and  relations  of  the  cell ;  chemical  force  is  the  determination  of 
the  composition  of  its  walls  and  contents,  and  with  these,  or  as  if  directing  them, 
that  vital  force,  different  from  them  and  from  all  other  known  physical  forces, 
is  in  operation,  by  virtue  of  which  the  cell  acquires  all  the  properties  that  charac- 
terize the  species  or  organ  to  which  it  is  attached,  and  becomes  capable  of  taking 
part  in  vital  processes — even  in  such  processes  as  those  in  which  itself  originated. 

"  Thus  the  vital  formative  force  seems  not  to  oppose  or  exclude,  but  to  include 
and  direct  physical  forces  that  issue  from  the  mere  matter  of  the  organic  body. 
It  may  therefore  be  believed  that  every  vital  act  is  accompanied  with  physical 
changes  in  the  active  matter ;  but  there  is  no  sufficient  evidence  that  such 
changes  ever  wholly  constitute  or  make  up  any  of  those  that  are  called  vital  acts. 
In  all  those  acts  or  processes,  some  force  is  exercised  peculiar  to  the  state  of  life, 
and  as  different  from  all  recognized  physical  forces  as  they  are  different  from  one 
another.  We  cannot  tell  how  much  in  each  act  of  the  living  body  is  physical, 
and  how  much  depends  on  the  peculiar  vital  force.  The  advancing  knowledge 
of  the  physical  sciences  does,  indeed,  prove  every  year  that  effects  which  used  to 
be  ascribed  to  vital  forces  are  due  to  the  operation  of  the  forces  of  chemistry 
and  mechanics  ;  and  it  may  be  observed,  generally,  that  the  substances  in  which 
the  processes  of  organic  life  are  most  actively  carried  on,  are  those  whose  chemi- 
cal composition  is  most  remote  from  that  of  inorganic  matter.  Still  many  things 
yet  remain,  observed  only  in  the  living  body,  so  completely  dependent  on  the 
maintenance  of  the  whole  state  of  life,  and  so  different  from  what  physical 
forces  ever  accomplish  in  dead  matter,  that  we  cannot  refer  them  to  the  opera- 
tion of  those  forces.  Any  hypothesis  which  would  abolish  the  idea  of  vital 
formative  force  would  be  much  less  reasonable  and  useful  than  that  which  ad- 
mits it ;  indeed,  unless  we  admit  the  existence  of  such  a  force  in  the  processes 
of  organic  life,  and  adopt  the  language  which  the  hypothesis  suggests,  it  is 
hardly  possible  to  express  the  ordinary  facts  of  Physiology."3 — Ed.~] 

3.   General  Survey  of  the  Life  of  Man. 
128.  It  will  be  advantageous,  before  proceeding  further,  to  apply  the  doctrines 

1  Lecture  introductory  to  the  course,  on  the  Institutes  of  Medicine  in  the  University  of 
Pennsylvania,  by  Samuel  Jackson,  M.  D.,  Philadelphia,  1851. 

2  Manual  of  Physiology,  by  Wm.  Senhouse  Kirkes,  M.  D.,  assisted  by  James  Paget, 
F.  R.  S.:  Philadelphia,  Lea  &  Blanchard,  p.  39,  Am.  Ed. 


GENERAL  SURVEY  OF  THE  LIFE  OF  MAN.  149 

which  it  has  been  the  purpose  of  the  preceding  section  to  point  out  and  illus- 
trate, to  the  history  of  Human  Life,  considered  under  its  most  general  aspect. 
The  germ  of  the  Human  organism,  derived  from  the  vital  operations  of  its 
parents,  must  be  considered  as  possessing  a  property  or  capacity,  whereby,  when 
it  is  placed  in  the  requisite  material  conditions,  and  subjected  to  a  certain  dynami- 
cal agency,  it  evolves  itself  into  the  complete  fabric,  which  is  subsequently  main- 
tained by  the  continuance  of  the  same  agencies.  And  this  property  is  so  far 
peculiar,  that  the  germ  of  Man  can  never  be  evolved  into  any  other  form  than 
the  Human,  although  it  may  attain  this  but  very  imperfectly.  It  is,  however, 
a  purely  passive  capacity ;  and  the  germ  must  be  acted  on  by  a  force  external  to 
it,  before  it  can  advance  a  single  step  in  the  developmental  process.  This  force 
is  Heat,  which,  being  supplied  by  the  parental  organism,  is  converted  by  the 
instrumentality  of  the  germ  into  the  Vital  force,  whereby  it  appropriates  the 
nutrient  materials  supplied  to  it,  and  converts  these  into  living  tissue.1  These 
nutrient  materials,  prepared  by  the  parent,  are  stored  up  in  the  ovum  in  suffi- 
cient quantity  to  serve  for  the  early  development  of  the  embryo,  until  it  can 
obtain  them  from  other  sources ;  but  while  their  quantity  is  adequate,  in  the 
Oviparous  animal,  to  serve  for  the  evolution  of  its  fabric  into  such  a  degree  of 
completeness  as  enables  it  to  ingest  and  appropriate  its  further  supplies  for  itself, 
it  suffices  in  the  Mammal  for  little  else  than  to  enable  the  germ  to  evolve  an 
apparatus  whereby  it  may  receive  a  continued  supply  more  directly  imparted  to 
it  from  the  bloodvessels  of  the  mother.  The  first  step  in  the  process  of  evolu- 
tion consists  in  mere  growth,  that  is,  in  the  multiplication  of  cells  by  duplicative 
subdivision,  without  any  departure  from  the  primitive  type ;  but  gradually  we 
see  indications  of  development,  in  the  multiplication  of  cells  in  particular  direc- 
tions, whereby  the  foundation  is  laid  of  the  principal  organs  of  the  fabric,  and 
in  the  metamorphoses  of  certain  of  them  into  the  tissues  which  are  characteristic 
of  the  perfect  organism ;  and  it  is  in  these  two  particulars  alone,  that  the  later 
stages  of  embryonic  life  essentially  differ  from  the  earlier.  During  all  this  time, 
Heat  is  being  continually  supplied  by  the  parent  and  appropriated  by  the  em- 
bryo; which,  at  its  period  of  maturity,  exhibits  the  result  of  the  continued 
operation  of  the  organizing  force,  and  of  its  action,  through  the  instrumentality 
of  the  germ  (in  the  first  place)  and  (subsequently)  of  the  living  fabric  that  has 
had  its  origin  in  it,  upon  the  nutrient  materials  with  which  it  has  been  sup- 
plied.— Up  to  this  time,  there  has  been  very  little  expenditure  of  Vital  force  in 
anything  else  than  the  formation  of  tissue ;  for  the  life  of  the  embryo  is  one 
rather  of  organic  or  vegetative,  than  of  animal  activity ;  the  action*  of  the  heart, 
and  the  occasional  reflex  movements  of  the  limbs,  being  its  only  manifestations 
of  nervo-muscular  power.  And  thus  it  seems  to  be,  that  the  formative  capacity 
is  greater  during  embryonic  life  than  at  any  subsequent  period,  and  greater  in 
its  earlier  than  in  its  later  stages ;  so  that  we  have  not  only  evidence  of  an 
extraordinary  power  of  regenerating  parts  which  have  been  lost  by  disease  or 
accident,  as  shown  in  attempts  at  the  reproduction  of  entire  limbs  after  their 
" spontaneous  amputation;"  but  there  is  also  not  unfrequently  an  absolute 
excess  of  productive  power,  as  shown  in  the  development  of  supernumerary 
organs,  which  may  even  proceed  to  the  extent  of  the  complete  duplication  of  the 
entire  body,  by  the  early  subdivision  of  the  embryonic  structure  into  two  inde- 
pendent halves.  (See  CHAP.  xix.  SECT.  4.) 

1  This  is  seen  obviously  enough  in  the  incubation  of  Birds,  in  which  the  contact  of  the 
surface  of  the  body  imparts  that  heat  to  the  germ  which  it  derives  in  Mammals  from  the 
textures  wherein  it  is  imbedded.  It  is  curious  to  observe  that  in  several  cold-blooded 
animals,  there  is  a  special  provision  for  generating  heat,  when  the  developmental  processes 
are  being  actively  carried  on ;  as  in  the  maturation  of  the  pupae  of  Bees,  and  the  evolution 
of  the  embryo  within  the  egg  in  certain  viviparous  Reptiles.  See  "Prin.  of  Phys.,  Gen. 
and  Comp.,"  §£  623  and  725,  Am.  Ed. 


150         OF    THE    STRUCTURAL   ELEMENTS   OF   THE    HUMAN   BODY. 

129.  From  the  time  of  its  entrance  into  the  world,  however,  the  condition  of 
the  Human  infant  is  essentially  changed.     It  is  no  longer  supplied  with  nutri- 
ment by  the  direct  transmission  of  organizable  materials  from  the  circulating 
fluid  of  the  mother  to  its  own ;  but  obtains  it  by  the  processes  of  digestion,  ab- 
sorption, and  assimilation,  which  involve  a  certain  expenditure  of  vital  force  in 
the  performance  of  the  chemical  and  vital  changes  in  which  these  processes  con- 
sist.    Thus  the  secretion  of  the  gastric,  biliary,  and  pancreatic  fluids  is  a  truly 
vital  process,  although  the  action  of  these  fluids  upon  the  alimentary  materials 
may  be  purely  chemical ;  so,  again,  although  part  of  the  process  of  absorption 
is  effected  by  purely  physical  agencies,  another  part  involves  the  development 
and  active  agency  of  cells,  and  thus  occasions  a  demand  for  vital  force ;  and  the 
further  preparation  of  the  absorbed  materials  for  the  purposes  of  nutrition  seems 
also  to  require  an  expenditure  of  that  which,  for  the  sake  of  convenience,  we 
have  termed  the  "cell-force."     Thus,  then,  even  as  regards  these  preliminary 
operations,  the  infant  is  placed  in  a  very  different  condition  from  the  intra-ute- 
rine  embryo ;  and  in  order  that  the  change  may  not  be  too  sudden,  the  nutri- 
ment provided  by  Nature  for  the  early  period  of  infantile  life  is  such  as  to 
occasion  the  least  possible  demand  upon  its  vital  powers  for  the  preparation  of 
the  organizable  material  which  is  required  for  its  further  growth  and  develop- 
ment.    But  the  transition  is  a  most  important  one  in  another  particular ;  the 
infant  is  now  thrown  in  great  degree  upon  its  own  resources  for  the  generation 
of  its  heat ;  and  this  it  is  enabled  to  accomplish  by  the  combustion  of  a  portion 
of  its  food  which  is  specially  provided  for  the  purpose,  this  combustion  being 
promoted  by  the  arrangements  for  that  active  respiration  which  now  supersedes 
the  very  limited  aeration  of  its  circulating  fluids  that  was  sufficient  during  foetal 
life.     Now  in  the  movements  of  the  respiratory  muscles  and  of  the  walls  of  the 
alimentary  canal,  we  have  a  new  source  of  expenditure  of  vital  force,  and  of 
destruction  of  tissue;  and  this  expenditure  is  progressively  augmented,  as  the 
motions  of  the  body  and  limbs  become  increasingly  active.     Thus  we  find  that 
the  formative  powers  are  not  exercised  during  childhood  and  youth,  solely  in 
the  construction  and  augmentation  of  the  fabric  (as  they  were  during  embryonic 
life),  since  there  is  a  constant  demand  upon  them  for  its  maintenance  ;  and  this 
demand  becomes  greater  and  greater,  in  proportion  to  the  exercise  of  the  Animal 
powers. 

130.  At  the  same  time  there  appears  to  be  a  progressive  reduction  in  the 
"  germinal  capacity ;"  for  not  only  is  there  to  be  observed  a  diminishing  aptitude 
for  the  production  of  new  parts  (as  shown,  for  example,  in  the  cessation  of  the 
production  of  new  tooth-sacs  by  gemmation  from  the  old,  the  last  operation  of 
this  kind  being  that  by  which  the  "dentes  sapientise"  are  originated  (§  285)), 
but  we  also  perceive  a  decrease  in  the  power  of  repairing  the  ravages  which 
disease  or  injury  may  have  made  in  the  organism  as  previously  formed.     Still, 
however,  this  capacity  manifests  itself  in  a  very  remarkable  manner  during  the 
whole  period  of  growth  ;  being  most  obviously  displayed  in  the  complete  evolu- 
tion of  the  generative  apparatus,  the  condition  of  which  was  previously  rudiment- 
ary ;  but  being  in  reality  yet  more  remarkably  exhibited  in  the  various  acts  by 
which  the  type  or  pattern  of  the  organism  is  maintained  and  completed,  not- 
withstanding the  various  influences  tending  to  its  degradation.     For  it  must  be 
borne  in  mind,  that  the  growth  of  the  body  of  Man,  or  of  that  of  any  of  the 
higher  Animals,  takes  place  in  a  manner  essentially  different  from  that  of  the 
Vegetable  fabric ;  the  latter  mainly  consisting  in  addition  to  the  parts  already 
formed,  whilst  the  former  is  effected  by  a  continual  development  of  new  structure 
in  place  of  the  old.     Thus  in  the  Tree  we  observe,  year  by  year,  the  same  trunk, 
the  same  branches,  the  same  roots ;  and  the  only  difference  which  we  notice 
between  the  young  tree  and  the  old  one  consists  in  the  increased  thickness   of 
the  original  stem  and  of  its  ramifications,  which  is  shown  by  a  transverse  section 


GENERAL  SURVEY  OF  THE  LIFE  OF  MAN.  151 

to  depend  entirely  upon  the  enclosure  of  the  original  in  new  layers  of  wood  pro- 
gressively developed  around  it,  and  in  the  greater  number  and  extent  of  the 
smaller  twigs  and  rootlets,  which  are  put  forth,  year  by  year,  from  the  larger. 
When  we  compare,  on  the  other  hand,  a  single  limb  of  the  adult  man  with  that 
of  the  infant,  we  find  that  the  position  of  every  part  of  it  has  changed.  The 
same  bones,  muscles,  tendons,  ligaments,  bloodvessels,  nerves,  &c.,  are  recog- 
nizable in  both  cases;  and  maintain,  with  little  variation,  the  same  relative  po- 
sitions. But  the  bone  has  swollen,  as  it  were,  in  every  direction,  so  that  its 
very  cavity  is  now  of  absolutely  larger  diameter  than  the  entire  shaft  of  the 
bone  of  the  infant,  whilst  the  whole  length  of  the  latter  would  constitute  but  a 
fraction  of  the  distance  that  now  intervenes  between  its  extremities.  With  the 
enlargement  of  the  bone,  the  points  of  muscular  attachment  are  of  course  sepa- 
rated from  each  other ;  and  the  muscles  themselves  undergo  a  similar  augment- 
ation, as  do  likewise  all  the  soft  tissues  connected  with  them ;  these  seeming, 
like  the  bone,  to  have  swollen  by  a  process  of  interstitial  growth,  rather  than 
to  have  simply  received  additions  to  their  surface  and  extremities.  Now  it  will 
be  shown  hereafter  (§  267),  that  this  enlargement  is  effected,  in  the  case  of  the 
Bone,  not  by  a  mere  superficial  addition  (such  as  that  which  causes  the  shell  of 
the  Echinus  to  swell  from  the  size  of  the  head  of  a  pin  to  that  of  the  head  of  a 
child,  the  new  matter  being  developed  at  the  edges  of  the  numerous  polygonal 
plates  of  which  it  is  composed),  but  by  a  combination  of  the  processes  of  absorp- 
tion and  of  deposition  ;  or  rather,  in  fact,  by  the  continual  progress  of  degene- 
ration and  death,  consentaneously  with  every  new  production  of  living  organized 
tissue.  And  what  is  true  of  the  bone  is  true  also,  there  is  good  reason  to  be- 
lieve, of  the  Muscles  and  all  the  softer  organs,  the  normal  duration  of  whose 
individual  parts  is  naturally  less ;  so  that  their  enlargement  seems  essentially 
to  consist  in  the  excess  of  production  over  the  disintegration  which  is  continually 
taking  place  in  them,  this  disintegration  (as  shown  by  the  amount  of  the  urea, 
carbonic  acid,  &c.,  which  are  excreted)  being  far  more  rapid  during  the  period 
of  growth  than  it  is  in  the  subsequent  stages  of  life. 

131.  That  the  germinal  capacity,  though  inferior  to  that  of  the  embryo,  still 
persists  in  a  high  degree  during  the  period  of  childhood  and  youth,  is  further 
shown  in  the  readiness  with  which  the  effects  of  injuries  and  disease  are  recovered 
from  y  for  although  the  regeneration  of  lost  parts  does  not  take  place  to  nearly 
the  same  extent  as  during  early  embryonic  life,  yet,  up  to  a  certain  point,  it  is 
effected  with  great  completeness,  and  with  much  greater  rapidity  than  at  later 
epochs.  It  is  still,  in  fact,  rather  in  the  exercise  of  formative  power,  than  in 
the  production  of  nervo-muscular  vigor,  that  the  vital  force  of  this  period  is 
displayed  ]  and  we  may  readily  trace  such  a  relation  of  reciprocity  between  these 
two  modes  of  its  manifestation,  as  is  strongly  indicative  of  the  community  of 
their  source.  For  it  is  familiar  to  every  observer,  that,  when  the  growth  of  a 
child  or  a  young  person  is  peculiarly  quick,  its  nervo-muscular  energy  is  usually 
feeble,  and  its  power  of  endurance  brief,  in  comparison  with  that  which  can  be 
put  forth  by  one  whose  frame  is  undergoing  less  rapid  increase.  And  we  observe, 
moreover,  that  the  capacity  of  resistance  to  depressing  influences  of  various  kinds, 
which  is  a  no  less  decided  manifestation  of  the  vital  power  of  the  organism  (see- 
ing that  these  influences  are  of  a  kind  which  tend  towards  its  death),  is  possessed 
by  the  latter  in  a  far  higher  degree  than  by  the  former. — Under  one  form  or 
the  other,  however,  we  must  recognize  the  existence  of  a  high  degree  of  vital 
power  during  the  period  of  childhood  and  adolescence ;  and  this  power  is  sus- 
tained by  the  large  consumption  of  food;  for  this  affords  not  merely  the  mate- 
rials largely  required  for  the  construction  of  the  fabric  (which  may  be  said  to 
bo  in  continual  progress  of  pulling-down  and  rebuilding,  all  the  old  materials 
being  carried  away  as  useless),  but  also  those  which  serve  for  the  maintenance 
of  the  heat  of  the  body,  and  which  thus  supply  the  force  which  is  requisite  for 


152         OF   THE    STRUCTURAL   ELEMENTS   OF   THE   HUMAN   BODY. 

the  sustentation  of  its  activity.  The  human  infant  at  first  possesses  but  a  feeble 
heat-producing  power;  and  the  lower  the  temperature  to  which  it  is  exposed, 
the  more  does  it  depend  upon  some  external  source  of  warmth.  As  its  digestive 
capacity  improves,  however,  and  it  can  appropriate  an  adequate  supply  of  food, 
its  calorific  power  augments;  for  its  rapid  circulation  and  active  respiration 
enable  the  combustive  process  to  be  performed  with  an  energy  greatly  surpassing 
that  which  is  displayed  in  later  life,  as  is  shown  in  the  quantity  of  carbonic  acid 
thrown  off.  And  thus,  as  it  is  from  its  food  that  the  organism  derives  not 
merely  its  materials  but  its  vital  force,  and  as  the  expenditure  of  both  is  pecu- 
liarly rapid,  it  comes  to  pass  that  the  dependence  of  life  upon  a  continual  supply 
of  food  is  far  more  close  at  this  period  than  subsequently;  so  that  when  children 
and  adults  are  subjected  at  the  same  time  to  complete  or  partial  starvation,  the 
former  succumb  much  earlier  than  the  latter. 

132.  The  period  of  adult  age  is  marked  by  an  increase  alike  in  the  nervo- 
muscular  power  of  the  body,  and  in  its  general  vigor  and  endurance ;  the  aug- 
mentation of  the  latter  being  most  strongly  displayed  in  the  activity  of  the 
generative  function.     Still  it  cannot  be  said  that  its  vital  force  is  on  the  whole 
increased  in  proportion  to  its  bulk ;  for  the  formative  power  is  decidedly  dimin- 
ished.    The  production  of  new  tissue  is  now  for  the  most  part  limited  to  the 
replacement  of  that  which  has  become  effete  by  use;  there  is  no  longer  a  capa- 
city for  the  production  of  new  organs,  and  comparatively  little  for  the  augmen- 
tation of  those  already  existing;    the  increase  of  the  uterine  and  mammary 
structures,  during  the  period  of  gestation,  being  the  most  important  examples  of 
formative  power,  and  these  presenting  themselves  in  the  sex  in  which  there  is 
least  of  nervo-muscular  activity  and  of  general  vigor.     We  should  infer,  then, 
that  the  " germinal  capacity"  is  now  on  the  decline;  and  this  further  appears 
from  the  inferior  energy  and  completeness  with  which  the  reparative  processes 
are  performed,  as  compared  with  the  mode  in  which  they  are  executed  during 
the  period  of  growth.     Moreover,  the  ordinary  rate  of  waste  or  degeneration  of 
tissue  is  now  much  less  rapid  than  during  the  period  of  growth;  for  we  have 
seen  that  decay  and  removal,  in  the  latter  case,  are  among  the  very  conditions 
of  increase ;  whilst  in  the  former,  they  proceed,  for  the  most  part,  only  from 
the  expenditure  of  the  vital  powers  of  the  tissues,  consequent  upon  their  func- 
tional activity.— The  whole  nisus  of  development,  in  fact,  during  this  period, 
appears  to  be  directed  towards  the  maintenance  of  the  organism  in  the  state 
which  it  had  acquired  at  its  commencement,  by  the  regeneration  of  its  tissues  as 
fast  as  they  undergo  disintegration,  and  by  the  renovation  of  its  vital  force  in 
proportion  as  this  is  expended.     There  is  consequently  a  less  demand  for  aliment- 
ary material,  than  during  the  previous  periods  (allowance  being  made  for  the 
augmented  bulk  of  the  body) ;  the  proportional  amount  of  heat  produced  (as 
indicated  by  the  carbonic  acid  exhaled)  is  also  less ;  and  the  dependence  of  life 
upon  a  constant  supply  of  aliment  is  far  less  close. 

133.  The  decline  of  life  exhibits  a  much  more  obvious  diminution  of  the 
whole  vital  power  of  the  organism ;  for  not  only  is  its  formative  activity  now 
greatly  reduced,  but  its  nervo-muscular  energy  and  general  vigor  progressively 
diminish,  and  its  generative  power  declines  or  ceases  entirely.     Of  this  diminu- 
tion in  formative  power,  we  have  evidence  in  the  entire  absence  of  any  attempt 
at  new  development,  in  the  less  perfect  and  more  tedious  manner  in  which  the 
losses  of  substance  occasioned  by  disease  or  injury  are  recovered  from,  and  in 
the  gradual  degeneration  of  the  organism  in  general.     The  tissues  which  are 
rendered  effete  by  their  functional  activity  are  not  any  longer  replaced  in  their 
normal  completeness :  for,  either  the  quantity  of  new  tissue  is  inadequate,  so  that 
the  bulk  of  the  organs  is  obviously  reduced;  or  their  quality  is  rendered  imper- 
fect, by  the  production  of  structures  in  various  phases  of  degeneration  (especially 
the  fatty),  in  place  of  those  which  had  been  previously  developed  in  the  fullest 


OP   THE   BLOOD.  —  GENERAL   CONSIDERATIONS.  153 

completeness.  The  inferiority  of  nervo-muscular  energy  and  of  general  vigor 
are  thus  evidently  the  result  of  the  deficiency,  and  not  (as  in  the  period  of 
growth)  of  the  excess,  of  formative  power ;  and  in  proportion  as  the  "  waste"  of 
the  tissues  consequent  upon  their  functional  activity  is  more  rapid  than  their 
renovation,  a  progressive  diminution  must  take  place.  It  is  obvious  that  the 
cause  of  this  decline  must  lie  within  the  organism  itself;  since  the  external  con- 
ditions remaining  the  same,  the  same  amount  of  vital  activity  is  no  longer  mani- 
fested ;  and  we  can  scarcely  attribute  it  to  any  other  source,  than  a  gradual 
decline  in  the  "germinal  capacity/7  which  seems  to  set  a  limit  to  the  life  of  the 
entire  organism,  as  it  does  to  that  of  the  single  cell.  For,  when  neither  disease 
nor  accident  shortens  what  may  be  considered  the  normal  term  of  life,  there  is 
a  gradual  diminution  in  every  kind  of  vital  activity,  until  it  entirely  ceases ;  the 
formative  power  seems  progressively  to  exhaust  itself,  until  no  assistance  from 
artificial  heat,  no  supply  of  the  most  nutritious  food,  can  any  longer  avail  for  the 
generation  of  new  tissue;  and  the  nervo-muscular  energy  gradually  declines, 
until  at  last  even  those  actions  on  which  the  circulation  and  respiration  entirely 
depend  can  no  longer  be  performed,  and  with  the  cessation  of  these  functions  the 
life  of  the  entire  organism  becomes  extinct. — Such  we  may  consider  to  be  the 
mode  in  which  Death  normally  occurs.  Various  abnormal  influences,  however, 
may  bring  about  this  final  result,  at  an  earlier  period,  and  in  different  modes; 
these  will  be  considered  on  a  future  occasion  (CHAP.  xxi.). 


CHAPTER   IV. 

OP  THE  BLOOD;  ITS  PHYSICAL  CHARACTERS,  CHEMICAL 
COMPOSITION,  AND  VITAL  PROPERTIES. 

1.    General  Considerations. 

134.  IN  the  organism  of  Man,  as  in  that  of  all  the  higher  Animals,  the 
materials  for  the  nutrition  of  every  portion  of  the  structure  are  supplied  by  the 
Blood,  which,  itself  formed  at  the  expense  of  the  organic  and  inorganic  constitu- 
ents of  the  Food,  is  constantly  circulating  through  the  vessels  during  the  whole 
of  life  ;  and  each  tissue  possesses  the  power  of  drawing  from  this  liquid,  and  of 
appropriating  to  its  own  use,  the  particular  components  of  its  substance,  which 
either  pre-exist  as  such  in  the  blood,  or  are  capable  of  being  readily  formed 
from  it  by  a  process  of  chemical  transformation.  The  supply  of  these  materials, 
however,  is  by  no  means  the  sole  purpose  of  the  Circulation  of  the  Blood ;  for  it 
also  furnishes  the  means  of  removing  the  effete  particles  which  are  set  free  by 
the  disintegration  of  the  tissues ;  these  being  drawn  into  the  current,  probably 
at  the  very  time  when  the  components  of  the  newly-forming  structures  are  given 
forth,  and  being  conveyed  by  it  to  the  various  organs  which  are  provided  for  their 
elimination.  Hence  the  Blood  not  only  contains  the  materials  for  the  renovation 
of  the  tissues,  but  also  the  products  of  their  decay :  but  there  is  an  important 
difference  in  the  proportion  of  these  two  sets  of  components ;  for  whilst  the  former 
make  up  the  principal  part  of  the  mass  of  the  fluid,  the  latter  are  only  detectable 
in  it  with  difficulty,  so  long  as  the  excretory  organs  maintain  their  normal  acti- 
vity ;  and  only  make  their  presence  obvious,  when  they  accumulate  unduly,  in 
consequence  of  the  retardation  or  suspension  of  the  eliminating  operations. — 
But  besides  thus  meeting  the  demand  occasioned  by  the  constructive  operations, 


154  OF   THE   BLOOD. 

and  preventing  the  results  of  the  destructive  from  exerting  an  injurious  influence 
on  the  system,  the  Circulation  of  the  Blood  serves  the  important  purpose  of 
introducing  Oxygen  from  the  atmosphere,  the  presence  of  which  appears  to 
be  an  essential  condition  of  the  peculiar  vital  activity  of  the  Nervous  and  Muscu- 
lar tissues,  whilst  it  is  also  required  in  various  other  metamorphoses  which  form 
part  both  of  the  constructive  and  of  the  destructive  operations;  and  just  as  the 
circulating  current  takes  up,  and  carries  to  their  appropriate  outlets,  the  various 
excretory  matters  which  are  set  free  in  the  course  of  its  nutrient  operations,  so 
does  it  also  imbibe  the  Carbonic  acid,  which  is  one  of  the  chief  products  of  the 
action  of  oxygen  upon  the  tissues  and  fluids  of  the  body,  and  convey  this  to  the 
lungs  and  skin  for  elimination.  This  product  is  continually  being  formed  in  such 
large  amount  that  its  presence  in  the  blood  can  always  be  readily  demonstrated ; 
and  if  its  elimination  be  checked  for  even  a  few  minutes,  it  accumulates  to  such 
an  extent  as  to  occasion  the  immediate  destruction  of  life. — But  besides  the 
Histogenetic  materials  and  oxygen,  on  the  one  hand,  and  the  various  products 
of  the  disintegration  of  the  tissues  on  the  other,  the  blood  contains  those  non- 
azotized  substances  which  are  received  into  it  for  the  purpose  of  supplying  the 
pabulum  of  the  combustive  process  ;  and  the  union  of  their  elements  with  oxygen 
introduced  from  the  atmosphere,  which  is  continually  going  on,  becomes  an  ad- 
ditional source  of  the  production  of  carbonic  acid,  and  of  its  injurious  accu- 
mulation if  its  elimination  be  checked. 

135.  From  the  variety  of  operations  to  which  the  Blood  is  subservient,  it 
naturally  follows  that  the  changes  which  it  undergoes  in  different  parts  of  its 
circulation  are  of  a  very  diversified  nature,  and  that  the  composition  of  the 
fluid  in  the  several  parts  of  its  course  will  be  far  from  uniform.     Between  the 
blood  which  is  being  distributed  by  the  Systemic  arteries  to  the  body  at  large, 
and  that  which  is  being  collected  from  it  again  by  the  systemic  veins,  after 
having  percolated  the  tissues,  there  is  not  only  an  obvious  difference  in  hue, 
which  indicates  an  important  change,  but  there  is  also  a  considerable  difference  in 
composition,  which  is  revealed  by  chemical  analysis :  and  a  difference  of  a  con- 
verse nature  presents  itself,  between  the  blood  that  is  on  its  way  to  be  distributed 
to  the  Lungs,  and  that  which  is  returning  from  them.     So,  again,  although  there 
is  no  obvious  dissimilarity  in  physical  characters  between  the  blood  which  is 
transmitted  to  the  Liver  by  the  vena  portae,  and  that  which  is  carried  off7  from 
it  by  the  hepatic  vein,  yet  chemical  analysis  reveals  a  very  remarkable  difference 
in  their  composition,  and  shows  that  the  blood  of  the  ascending  vena  cava  (above 
the  entrance  of  the  hepatic  vein),  that  of  the  right  cavities  of  the  heart,  and  that 
of  the  pulmonary  artery,  differs  from  all  other  blood  in  the  body,  in  containing 
an  appreciable  quantity  of  sugar  (§  45).     In  many  other  cases,  we  know  that  an 
important  difference  must  exist,  although  chemical  analysis  has  not  yet  detected 
it ;  thus,  the  blood  of  the  Renal  vein  must  be  more  free  from  the  components  of 
the  urinary  excretion  than  that  of  the  renal  artery  which  conveys  them  to  the 
kidney ;  whilst  the  blood  of  the  systemic  veins  in  general  must  contain  them 
in  greater  amount  than  their  corresponding  arteries,  since  they  are  discharged 
into  the  current  during  its  passage  through  the  tissues,  of  whose  disintegration 
they  are  among  the  products. — In  the  account  to  be  presently  given  of  the  Blood, 
those  most  general  characters  and  properties  will  be  first  described  which  it  pre- 
sents in  all  parts  of  its  circulation  ;  the  principal  differences  which  have  been 
substantiated  in  the  composition  of  the  blood  in  the  several  portions  of  its  circuit 
will  then  be  noticed ;  and,  lastly,  some  account  will  be  given  of  the  most  import- 
ant of  those  pathological  alterations  which  it  exhibits  in  disease. 

136.  The  precise  determination  of  the  quantity  of  Blood  contained  in  the 
body  is  more  difficult  than  might  have  been  at  first  supposed ;  and  the  estimates 
which  have  been  made  of  it  have  been  most  strangely  discrepant.     The  entire 
amount  which  flows  from  a  large  arterial  trunk,  freely  opened,  can  by  no  means 


GENERAL   CONSIDERATIONS.  155 

be  taken  as  a  measure ;  since,  however  freely  it  may  be  permitted  to  escape,  a 
considerable  quantity  still  remains  within  the  bloodvessels,  especially  if  the 
heart's  action  fail  before  the  loss  of  blood  has  proceeded  very  far,  so  that  it 
is  not  drawn  from  the  venous  system.  A  closer  approximation  may  be  made 
by  opening  several  vessels  at  once,  which  was  the  method  adopted  by  Herbst  j1 
who  estimated  the  proportion  of  the  weight  of  the  blood  to  that  of  the  entire 
body  to  be  as  1  : 12  in  the  Ox,  as  1  : 16  in  the  Dog,  as  1 : 18  in  the  Horse,  as 
1  : 20  in  the  Goat,  Calf,  Lamb,  and  Hare,  as  1  : 22  in  the  Sheep  and  Cat,  and 
as  1  : 24  in  the  Rabbit.  With  these  estimates,  the  conclusions  drawn  by  Vanner, 
from  his  recent  observations  in  the  abattoirs  of  Paris,  pretty  closely  correspond ; 
for  he  is  led  by  them  to  the  belief,  that  for  horned  cattle  in  general,  the  propor- 
tion does  not  vary  far  from  1 :  20.2  It  is  obvious,  however,  that  no  such  method 
can  give  more  than  a  minimum, ;  since,  even  after  the  most  complete  exsanguina- 
tion  that  the  freest  opening  of  the  vessels  can  permit,  a  considerable  quantity 
of  blood  is  still  retained  in  them,  and  especially  in  those  of  the  head.  And 
there  are  various  observations  which  lead  to  the  belief,  that  such  estimates  are 
far  too  low  as  regards  Man ;  since  it  appears  that  a  quantity  of  blood  equal  to  at 
least  one-tenth  of  the  weight  of  his  body  may  be  poured  forth  from  his  vessels 
within  a  short  time.  Still,  occurrences  of  this  kind,  of  which  Haller  has  brought 
together  an  interesting  collection,3  afford  but  an  unsafe  basis  for  our  estimate ; 
since  it  is  necessary  to  allow  for  the  fact,  that  when  the  vessels  are  becoming 
emptied  of  blood,  a  transudation  of  fluid  takes  place  into  them  from  the  surround- 
ing tissues,  as  is  evidenced  by  the  diminution  in  the  specific  gravity,  and  in  the 
increase  in  the  proportion  of  water,  which  are  apparent  when  even  the  first  and 
last  parts  of  the  blood  drawn  at  an  ordinary  venesection  are  compared  (§  162)  : 
so  that,  if  the  hemorrhage  be  going  on  for  some  hours,  a  much  larger  quantity 
of  fluid  may  be  poured  forth  from  the  vessels  than  was  ever  contained  within 
them  at  any  one  time;  and  if  liquids  be  ingested  during  its  continuance,  a  por- 
tion of  these,  being  at  once  received  into  the  circulating  current,  will  go  to  aug- 
ment the  amount  which  escapes  from  it.  Two  remarkable  instances  of  this  kind 
are  cited  by  Burdach4  from  Wrisberg,  who  states  that  a  female  who  died  from 
violent  rnetrorrhagia  lost  26  Ibs.  of  blood,  and  that  24  Ibs.  were  collected  from 
the  body  of  a  plethoric  female  who  had  suffered  death  by  decapitation.  In 
the  first  of  these  cases,  it  is  probable  that,  as  death  could  not  have  been  imme- 
diate, some  increase  took  place  from  the  fluids  of  the  body;  in  the  second, 
however,  the  suddenness  of  the  discharge  of  blood,  and  its  concurrence  with  the 
destruction  of  life,  must  have  prevented  any  considerable  augmentation  from  this 
source ;  and  if  any  such  increase  did  take  place,  it  probably  did  not  exceed  the 
amount  of  blood  remaining  undischarged  in  the  vessels. — Another  mode  of 
determining  the  total  amount  of  the  circulating  blood  has  been  proposed  by 
Prof.  Valentin;5  who  first  draws  a  sample  of  blood  from  an  animal,  and  ascer- 
tains the  proportion  of  water  which  it  contains,  then  injects  a  determinate  quantity 
of  water  into  the  vessels,  and  immediately  draws  fresh  samples  from  different 
parts  of  the  body,  in  which  also  he  ascertains  the  proportion  of  the  solid  to  the 
fluid  components ;  and  from  the  amount  of  dilution  which  the  last-drawn  blood 
exhibits,  as  compared  with  the  first  sample,  he  calculates  the  whole  bulk  of  the 
circulating  fluid.  From  these  data,  Prof.  Valentin  estimated  the  proportion  of 
blood  in  the  Dog  as  1 :  4?,  and  in  the  Sheep  as  1 :  5;  so  that,  applying  the  former 
of  these  proportions  to  the  Human  body,  a  man  weighing  145  Ibs.  would  have 

1  "De  Sanguinis  quantitate,  qualis  komini  adulto  et  sano  convenit."     Goettingee,  1822. 

2  "Comptes  Rendus,"  torn,  xxviii.  p.  649. 

8  "  Elementa  Physiologies,"  vol.  ii.  pp.  3,  4. 

4  "  Traite  de  Physiologic,"  traduit  par  Jourdain,  torn.  vi.  p.  119. 

6  "Repert.  fur  Anat.  und  Phys.,"  band  iii.  p.  281. 


156  OF   THE   BLOOD. 

32  Ibs.  of  blood,  and  a  woman  weighing  127  Ibs.  would  have  27  Ibs.  of  blood. 
It  can  scarcely  be  doubted  that  this  statement  is  too  high ;  and  it  is  not  difficult 
to  discern  an  important  fallacy  in  the  method  on  which  it  was  based.  For,  how- 
ever rapidly  the  operation  may  be  performed,  some  portion  of  the  water  injected 
will  transude  from  the  vessels  into  the  surrounding  tissues,  and  will  escape  by 
the  kidneys;  and  thus,  the  degree  of  its  dilution  being  diminished,  the  estimate 
of  the  total  amount  of  the  blood  will  be  raised  considerably  above  the  reality. — 
It  has  been  more  recently  proposed  by  more  than  one  experimenter  to  inject,  in 
place  of  water,  some  saline  compound,  whose  presence  in  the  blood  might  easily 
be  determined  quantitatively,  and  which  should  neither  be  so  poisonous  as  to 
produce  speedy  death,  nor  be  capable  of  such  rapid  transudation  as  to  escape  too 
readily  into  the  tissues  or  the  urine.  The  sulphate  of  alumina  has  been  employed 
for  this  purpose  by  Prof.  Blake1  (of  St.  Louis,  U.  S.) ;  and  his  experiments  lead 
to  the  conclusion  that  the  proportion  of  blood  in  the  body  of  a  Dog  is  as  1  :  8  or 
1:9;  so  that,  applying  the  same  proportion  to  Man,  the  quantity  of  blood  in  a 
Human  body  weighing  144  Ibs.  would  be  16  or  18  Ibs.  Several  circumstances 
lead  to  the  belief  that  this  estimate  is  not  far  from  the  truth ;  but  it  cannot  be 
doubted  that  a  considerable  variation  in  the  relative  amount  of  blood  will  exist 
among  different  individuals. 

2.  Physical,  Chemical,  and  Structural  Characters  of  the  Blood. 

137.  The  Blood,  as  it  flows  forth  from  an  opening  in  a  large  vessel,  is  an 
apparently  homogeneous  liquid,  possessing  a  slight  degree  of  viscidity,  with  a 
consistence  and  density  somewhat  greater  than  those  of  water,  but  especially 
distinguished  by  its  color,  which  is  usually  of  a  bright  scarlet  when  it  is  drawn 
from  an  artery,  and  of  a  dark  purple,  sometimes  almost  approaching  to  black, 
when  it  is  drawn  from  a  vein.  This  difference  of  color,  however,  is  by  no  means 
constant;  for  arterial  blood  may  sometimes  be  unusually  dark,  whilst  venous 
blood  is  occasionally  so  florid  that  it  might  almost  be  taken  for  arterial.  The 
former  condition  is  observable,  when  from  any  cause  the  respiratory  process  is 
imperfectly  performed,  and  may  be  especially  noticed  during  operations  per- 
formed under  the  influence  of  anaesthetic  agents ;  it  has  also  been  remarked  by 
Dr.  John  Davy,  as  usually  characterizing  the  arterial  blood  of  the  inhabitants 
of  hot  climates  f  but,  in  any  of  these  cases,  the  ordinary  arterial  hue  is  acquired 
by  the  blood  when  it  has  been  sufficiently  exposed  to  the  air.  The  florid  hue  is 
presented  by  the  venous  blood  of  animals  which  are  made  to  respire  pure  oxygen; 
but  it  seems  normal  with  some  individuals  whose  respiration  is  peculiarly  active. — 
The  specific  gravity  of  the  Blood  is  stated  by  Nasse,3  as  the  result  of  numerous 
observations,  to  vary  (within  the  limits  of  health)  between  1050  and  1059 ;  the 
average  being  taken  as  1055.  The  principal  source  of  this  variation  is  the  want 
of  constancy  in  the  proportion  of  the  red  corpuscles  in  the  blood ;  for  the  specific 
gravity  of  these,  when  separately  examined,  is  found  to  be  as  high  as  1088.5, 
whilst  that  of  the  liquid  in  which  they  float  is  no  more  than  1028;  and  hence  the 
specific  gravity  of  the  blood  of  men  is  usually  higher  than  that  of  women  (§  159), 
and  that  of  the  portion  of  blood  first  drawn  exceeds  that  of  the  portion  which 
flows  last  (§  162). — The  chemical  reaction  of  the  Blood  seems  to  be  invariably 
alkaline;  and  very  important  purposes  are  served  by  this  alkalinity  (§§  83,  84). — 
When  we  add  that  the  Blood  has  a  saltish  taste,  and  a  faint  odor  resembling 
that  of  the  pulmonary  and  cutaneous  exhalations  of  the  animal  from  which  it  is 

1  See  Prof.  Dunglison's  "  Human  Physiology,"  seventh  edit.  vol.  ii.  p.  102. 

2  "Anatomical  and  Physiological  Researches,"  vol.  ii.  p.  140. 

3  Wagner's  "Handworterbuch  der  Physiologic,"  "  Blut"  bandi.  p.  82. 


ITS   PHYSICAL,    CHEMICAL,    AND    STRUCTURAL   CHARACTERS.      157 

drawn,  we  have  enumerated  all  the  characteristics  which  can  be  made  out  by  the 
unassisted  senses. 

138.  When  the  Blood  is  examined  with  the  Microscope,  however,  either  im- 
mediately upon  being  drawn,  or  whilst  it  is  yet  circulating  in  the  vessels  of  the 
living  body  (as  in  the  foot  of  the  Frog,  the  wing  of  the  Bat,  or  any  other  mem- 
branous expansion  of  similar  transparency),  it  is  seen  that  its  apparent  homo- 
geneity is  not  real,  but  that  it  consists  of  two  very  different  components.     These 
are,  a  transparent  and  perfectly  colorless  liquid,  which  is  known  as  the  Liquor 
Sanguinis,  and  a  set  of  Corpuscles,  which  are  suspended  in  it :  the  great  mass 
of  these  last  present  a  distinctly  red  hue,  and  it  is  to  their  presence  alone  that 
the  color  of  the  blood  is  due ;  but  there  are  also  to  be  seen,  scattered  among  the 
red,  a  few  which  are  colorless,  and  which  differ  from  the  red  in  some  other  par- 
ticulars presently  to  be  noticed. — On  the  other  hand,  when  the  Blood  has  been 
drawn  from  the  body,  and  is  allowed  to  remain  at  rest,  it  undergoes  a  spontaneous 
coagulation,  in  the  course  of  which  it  separates  into  a  red  Crassamentum  and  a 
nearly  colorless  Serum.     The  "  crassamentum"  or  "  clot"  is  composed  of  a  net- 
work of  Fibrin  (§§  26,  27),  in  the  meshes  of  which  the  Corpuscles,  both  red  and 
colorless,  are  involved,  together  with  a  certain  amount  of  serous  fluid.     The 
"  serum/ ;  which  is  the  same  with  the  "liquor  sanguinis"  deprived  of  its  Fibrin, 
coagulates  by  heat,  and  is,  therefore,  known  to  contain  Albumen ;  and  if  it  be 
exposed  to  a  high  temperature,  sufficient  to  decompose  the  animal  matter,  a 
considerable  amount  of  earthy  and  alkaline  Salts  remains. — Thus  we  have  four 
principal  components  in  the  Blood :  namely,  Fibrin,  Albumen,  Corpuscles,  and 
Saline  matter.     In  the  circulating  blood,  they  are  thus  combined : — 

Fibrin          ~\ 

Albumen      I  In  solution,  forming  Liquor  Sanguinis. 

Salts  J 

Corpuscles — suspended  in  Liquor  Sanguinis. 

But  in  coagulated  blood,  they  are  combined  as  follows  : — 
P      *      ,       I  Forming  Crassamentum  or  Clot. 
g  , ,  I  Remaining  in  solution,  forming  Serum. 

The  change  from  the  one  condition  to  the  other  is  due  to  the  fibrillation  of  the 
Fibrin,  which  usually  takes  place  so  speedily  as  to  involve  the  Corpuscles  float- 
ing in  the  "  liquor  sanguinis"  before  they  have  time  to  subside,  although,  under 
various  conditions  hereafter  to  be  described  (SECT.  3),  it  may  occur  in  such  a 
manner  that  the  clot,  or  a  portion  of  it,  is  left  colorless. — The  Fibrin,  Albumen, 
and  Saline  components  of  the  Blood  present  no  other  characters  than  those  which 
have  been  already  detailed  in  the  general  account  of  these  substances  (CHAP,  n.) ; 
and  the  only  constituents  remaining  to  be  described,  therefore,  are  the  Cor- 
puscular, which  are  not  mere  organic  compounds,  but  have  a  regularly  organized 
structure. 

139.  The  Red  Corpuscles  of  the  Blood  (commonly,  but  erroneously,  termed 
"  globules")  are  cells  of  a  flattened  or  discoidal  form;  which,  in  Man,  as  in  most 
of  the  Mammalia,  have  a  distinctly  circular  outline.     In  the  disks  of  Human 
blood,  when  this  is  examined  in  its  natural  condition,  the  sides  are  somewhat 
concave ;  and  there  is  a  bright  spot  in  the  centre,  which  has  been  regarded  by 
many  as  indicating  the  existence  of  a  nucleus ;  though  it  is  really  nothing  else 
than  an  effect  of  refraction,  and  may  be  exchanged  for  a  dark  one  by  slightly  alter- 
ing the  focus  of  the  Microscope  (Fig.  11).     The  form  of  the  disk  is  very  much 
altered  by  various  reagents;  for  the  membrane  which  composes  its  exterior,  or  cell- 
wall,  is  readily  permeable  by  liquids ;  so  as  to  admit  of  their  passage,  according  to 


158  OF   THE   BLOOD. 

the  laws  of  Endosmose,  either  inwards  or  outwards,  as  the  relative  density  of  the 

contents  of  the  cell  and  of  the  surrounding 

Fig.  11.  fluid  may  direct.     Thus,  if  the  Red  Cor- 

puscles be  treated  with  water,  or  with  a 
solution  of  sugar,  albumen,  or  salt,  which 
is  of  less  density  than  the  liquor  sanguinis, 
there  is  a  passage  of  this  liquid  into  the 
cell ;  the  disk  first  becomes  flat,  and  then 
double  convex,  so  that  the  central  spot 
disappears;  and  by  a  continuance  of  the 
same  process,  it  at  last  becomes  globular, 
and  finally  bursts,  the  cell-wall  giving 
way,  and  allowing  the  diffusion  of  its  con- 
Red  Corpuscles  of  Human  Blood;  represented  ^^  through  the  Surrounding  liquid.  If, 
at  a,  as  they  are  seen  when  rather  beyond  the  ,  ,  °  ,  ,  ,  -p»  i  /~i  i 

focus  of  the  Microscope;  and  at6,as  they  appear  ™  the  Other  hand  the  Red  Corpuscles 
when  within  the  focus.  Magnified  400  diameters.  D6  treated  With  a  thlCK  Syrup,  Or  With  a 

solution  of  albumen  or  of  salt,  they  will 

be  more  or  less  completely  emptied,  and  caused  to  assume  a  shrunken  appear- 
ance; the  first  effect  of  the  process  being  to  increase  the  concavity,  and  to 
render  the  central  spot  more  distinct.1  It  is  probable  that  the  Blood-corpuscles, 
even  whilst  they  are  circulating  in  the  living  vessels,  are  liable  to  alterations  of 
this  kind,  from  variations  in  the  density  of  the  fluid  in  which  they  float ;  and 
that  such  alterations  may  be  constantly  connected  with  certain  disordered  states 
of  the  system.3  Thus,  even  without  such  an  alteration  in  the  Blood  as  would 
constitute  disease,  its  proportion  of  water  may  be  temporarily  so  much  dimin- 
ished by  diuresis  or  excessive  perspiration,  unbalanced  by  a  corresponding 
ingestion  of  liquid,  that  the  corpuscles  may  be  made  to  present  a  granulated 
edge  ;  which  is  rendered  smooth  again  by  the  dilution  of  the  liquor  sanguinis 
with  water.  We  hence  see  the  necessity,  in  examining  the  Blood  microscopic- 
ally, for  employing  a  fluid  for  its  dilution,  that  shall  be  as  nearly  as  possible  of 
the  same  character  with  its  ordinary  "liquor  sanguinis/'3 — Microscopic  observers 
were  formerly  divided  upon  the  question,  whether  or  not  the  Red  Corpuscles  of 
the  blood  of  Man  and  other  Mammalia  contain  a  nucleus;  but  of  late  there  has 
been  a  general  accordance  in  the  statement  that,  in  the  fully-formed  disk,  no 
nucleus  is  discoverable,  although  it  may  be  sometimes  seen  in  cells  whose 
formation  seems  to  be  incomplete ;  and  from  the  observations  of  Mr.  Paget  and 
of  Mr.  Wharton  Jones,  it  would  seem  that  we  are  to  regard  the  absence  of 
nucleus  as  marking  a  more  advanced  stage  of  development,  than  that  which 
obtains  in  the  blood-corpuscles  of  the  lower  Vertebrata,  or  in  the  early  condition 
of  those  of  the  highest  (§§  150,  151). 

1  A  large  number  of  experiments  of  this  kind  were  made,  and  their  results  accurately 
recorded,  by  Hewson  (see  his  "Inquiry  into  the  Properties  of  the  Blood,"  1782,  and  his 
"  Description  of  the  Red  Particles  of  the  Blood,"  1788),  who  drew  from  them  the  inference 
of  the  vesicular  character  of  the  Red  Corpuscles.     These  experiments  were  repeated  and 
varied  by  other  physiologists,  of  whose  results  a  table  has  been  given  by  Mr.  Ancell  ("Lec- 
tures on  the  Physiology  and  Pathology  of  the  Blood,"  in  the  "  Lancet,"  Dec.  7,  1839) ;  but 
the  facts  stated  in  the  text  are  those  of  most  importance,  and  their  true  rationale  seems  to 
have  been  first  given  by  Dr.  G.  0.  Rees  and  Mr.  S.  Lane.     (See  their  Memoir  "On  the 
Structure  of  the  Blood-Corpuscle,"  in  "Guy's  Hospital  Reports,"  No.  xiii.) 

2  See  Dr.  G.  0.  Rees's  Gulstonian  Lectures,  in  the  "  Medical  Gazette"  for  1845. 

3  By  Wagner,  the  filtered  serum  of  frog's  blood  is  recommended  for  this  purpose. 
Weak  solutions  of  salt  or  sugar,  and  urine,  answer  tolerably  well;   but  Mr.   Gulliver 
remarks  that  all  addition  must  be  avoided,  when  it  is  intended  to  measure  the  corpuscles, 
or  to  ascertain  their  true  forms ;  since  even  the  serum  of  one  Mammal  reacts  injuriously 
on  the  blood  of  another.     See  "Philos.  Magazine,"  Jan.  and  Feb.  1840. 


ITS   PHYSICAL,    CHEMICAL,    AND    STRUCTURAL   CHARACTERS.       159 

140.  In  all  Oviparous  Vertebrata,  without  any  known  exception,  the  Red 
Corpuscles  are  oval — the  proportion  be- 
tween their  long  and  their  short  diame-  FiS-  12- 

ters,  however,  being  much  subject  to 
variation }  and  their  nuclei  may  always 
be  brought  into  view,  by  treatment  with 
acetic  acid,  when  not  at  first  visible. 
In  the  red  particles  of  the  Frog,  which 
are  far  larger  than  those  of  Man,  a  nu- 
cleus can  be  observed  to  project  some- 
what from  the  central  portion  of  the 
oval,  even  during  their  circulation  (Fig. 
12,  1, 1) ;  and  it  is  brought  into  extreme  Red  Corpugcleg  of  Frog,s  Blood.  1;  1?  their  flat_ 

distinctness  by  the  action  Of  acetic  acid,  tened  face;  2,  particle  turned  nearly  edgewise;  3, 
Which  renders  the  remainder  of  the  par-  lymph-globule;  4,  red  corpuscles  altered  by  dilute 
tide  extremely  transparent,  whilst  it  acetic  acid.  Magnified  500  diameters. 

gives  increased  opacity  to  the  nucleus, 

which  is  then  seen  to  consist  of  a  granular  substance  (4).  In  the  still  larger 
blood-disk  of  the  Proteus  and  Siren,  this  appearance  is  yet  more  distinct ;  the 
structure  of  the  nucleus  being  so  evident,  without  the  addition  of  acetic  acid, 
that  its  granules  can  be  counted.1 

141.  The  form  of  the  Red  Corpuscles  is  not  unfrequently  seen  to  change 
during  their  circulation ;  but  this  is  generally  in  consequence  of  pressure,  from 
the  effects  of  which,  however,  they  quickly  recover  themselves.     In  the  capil- 
lary vessels,  they  sometimes    become    suddenly   elongated,   twisted,  or   bent, 
through  a  narrowing  of  the  channel ;  and  this  change  may  take  place  to  such  a 
degree  as  to  enable  the  disk  to  pass  through  an  aperture,  which  appears  very 
minute  in  proportion  to  its  diameter.     When  undergoing  spontaneous  decompo- 
sition, the  blood-disks  become  granulated,  and  sometimes  (as  long  since  noticed 
by  Hewson)  even  mulberry-shaped ;  and  particles  in  which  these  changes  appear 
to  be  commencing,  may  be  found  in  the  blood  at  all  times. — The  size  of  the 
blood-disks  is  liable  to  considerable  variation,  even  in  the  same  individual ;  some 
being  met  with  as  much  as  one-third  larger,  whilst  others  are  one-third  smaller, 
than  the  average.     The  diameter  of  the  corpuscles  bears  no  constant  relation  to 
the  size  of  the  animal,  even  within  the  limits  of  the  same  class ;  thus,  although 
those  of  the  Elephant  are  the  largest  among  Mammalia  (as  far  as  is  hitherto 
known),  those  of  the  Mouse  tribe  are  far  from  being  the  smallest;  being,  in  fact, 
more  than  three  times  the  diameter  of  those  of  the  Musk  Beer.     There  is,  how- 
ever, as  Mr.  Gulliver  has  remarked,  a  more  uniform  relation  between  the  size 
of  the  animal  and  that  of  its  blood-disks,  when  the  comparison  is  made  within 
the  limits  of  the  same  order.     In  Man,  their  diameter  varies  from  about  l-4000th 
to  l-2800th  of  an  inch,  the  average  diameter  being  probably  about  l-8200th ; 
and  their  average  thickness,  according  to  the  same  excellent  observer,  is  about 
l-12,400th  of  an  inch.2 — The  color  of  the  Red  Corpuscles  is  very  pale  when  they 
are  lying  in  a  single  stratum ;  and  it  is  only  when  we  see  three  or  four  super- 
posed one  upon  another,  that  the  full  deep-red  tint  of  their  contents  becomes 
apparent.     The  cause  of  the  difference  in  hue  between  the  corpuscles  of  arterial 
and  those  of  venous  blood  will  be  considered  hereafter  (§  166). 

1  See  " Penny  Cyclopaedia,"  Art.  "Siren." 

2  A  Tabular  summary  of  Mr.  Gulliver's  very  numerous  and  accurate  measurements  of 
the  Red  Corpuscles  of  the  Blood  of  different  animals,  from  all  the  classes  and  most  of  the 
orders  of  the  Vertebrate  series,  is  contained  in  the  "Proceedings  of  the  Zoological  Society," 
No.  cii.,  and  also  in  his  Edition  of  the  "Works  of  Hewson,"  already  referred  to,  published 
by  the  Sydenham  Society  (p.  237).     From  these,  the  following  measurements  of  the  blood 
of  domestic  animals  (expressed  in  fractions  of  an  English  inch)  maybe  selected,  as  the  most 


160 


OF   THE   BLOOD. 


142.  The  principal  part  of  the  substance  *of  the  Red  Corpuscles  is  formed  by 
the  two  compounds  Globulin  and  Hsematin,  whose  distinctive  characters  have 
been  already  described  (§§  23,  31).  That  the  Haematin  is  in  a  state  of  solu- 
tion in  the  contents  of  these  blood-cells,  cannot  be  doubted;  but  as  regards  the 
condition  of  the  Globulin  there  is  room  for  more  diiference  of  opinion,  some 
considering  it  to  be  also  in  a  fluid  state,  and  to  form  the  remainder  of  the  cell- 
contents,  whilst  others  have  regarded  it  as  the  constituent  of  the  cell-walls. 
To  the  latter  doctrine,  however,  the  liberation  of  Globulin  as  well  as  of  Hsema- 
tin,  when  the  Red  Corpuscles  are  caused  to  burst  by  being  treated  with  water 
(§  139),  appears  a  sufficient  objection,  the  cell-walls  themselves  not  being  dis- 
solved j  and  the  very  large  proportion  which  the  Globulin  bears  to  the  Haematin 
is  scarcely  less  significant. — The  following  is  given  by  Prof.  Lehmann  (op.  'cit.; 
band  ii.  p.  152)  as  the  relative  Chemical  constitution  of  the  Red  Corpuscles 
and  of  the  Liquor  Sanguinis,  which  there  is  a  great  advantage  in  thus  bringing 
into  comparison. 

likely  to  become  of  interest  in  Juridical  inquiries,  in  which  it  is  frequently  of  importance 
to  ascertain  the  precise  source  of  stains  whose  sanguineous  character  has  been  determined. 

.  1-4230 

.  1-4267 

.  1-4324 

.  1-4404 

.  1-4600 

.  1-5300 

.  1-6366 

Thus  it  appears  quite  possible  to  distinguish  the  blood  of  all  the  animals  enumerated,  from 
that  of  Man,  by  the  measurement  of  the  diameter  of  the  Red  Corpuscles ;  those  of  the  Dog 
and  of  the  Rodents  approaching  his  most  nearly  in  size,  whilst  those  of  the  Ruminant  and 
Pachydermatous  quadrupeds,  and  of  the  Cat,  are  considerably  smaller. — It  is  important, 
however,  to  bear  in  mind,  that  the  specimens  of  blood  submitted  to  examination  in  Juridical 
inquiries  will  for  the  most  part  have  been  dried ;  and  it  is,  therefore,  of  consequence  to 
know  the  comparative  dimensions  of  the  blood-disks,  after  they  have  been  submitted  to  this 
process.  These  are  given  as  follows,  by  Schmidt,  in  his  recent  work  on  the  diagnosis  of 
suspicious  spots  in  criminal  cases  ("Die  Diagnostik  verdachtiger  Flecke  im  Criminal- 
faller") ;  the  measurements  being  expressed  in  decimals  of  a  millimetre. 


Man     . 

Dog      . 
Hare    . 
Rabbit 
Rat 

.     1-3200 
M$ti*&   •         •     1-3532 
.     1-3560 
.     1-3607 
1-3754 

Pig     Hfc* 

Ox 
Red  Deer 

Cat     ..".,;; 
Horse 

Mouse 

Ass      . 

.         .         .     1-3814 
.     1-4000 

Sheep  . 
Goat     . 

Man 
Dog 

Mean. 
.      0.0077 
.     0.0070 

Rabbit 
Rat 
Pig 
Mouse 
Ox 
Cat 
Horse 
Sheep 

it»ft&*y 

.     0.0064 
.     0.0064 
.     0.0062 
.     0.0061 
/     .     0.0058 
•  .     0.0056 
.     0.0057 
.     .     0.0045 

Maximum. 

0.0080 
0.0074 
0.0070 
0.0068 
0.0065 
0.0065 
0.0062 
0.0060 
0.0060 
0.0048 


Minimum. 

0.0074 
0.0066 
0.0060 
0.0060 
0.0060 
0.0058 
0.0054 
0.0053 
0.0053 
0.0040 


The  relative  sizes  of  the  Red  Corpuscles  expressed  by  this  Table  will  be  seen  to  corre- 
spond closely  with  those  assigned  by  Mr.  Gulliver,  in  every  case  but  that  of  the  Pig,  with 
regard  to  which  there  must  certainly  be  a  mistake  on  one  side  or  the  other. — The  oval 
form  and  prominent  nucleus  of  the  Red  Corpuscles  of  all  the  oviparous  Vertebrata  enable 
them  to  be  distinguished  from  those  of  Man  without  the  slightest  difficulty ;  consequently 
no  question  can  ever  lie  between  a  stain  left  by  the  blood  of  a  Fowl,  a  Turtle,  or  a  Cod, 
and  that  left  by  Human  blood,  when  the  corpuscles  can  be  distinctly  made  out  with  the 
assistance  of  the  microscope. 


ITS   PHYSICAL,    CHEMICAL,    AND   STRUCTURAL   CHARACTERS.       161 


1000  parts  of  Red  Corpuscles  contain 
Water   .         .         .         .         .         .     688.00 
Solid  residue          .      "  .'        .         .     312.00 

Hsematin  (including  iron)       .         .       16.75 
Globulin  and  cell  membrane  .         .     282.22 
Fat        2.31 

1000  parts  of  Liquor  Sanguinis 
Water    
Solid  residue 

Fibrin  .         .         .         .        '.;•  ^ 

contain 
.     902.90 
.       97.10 

4.05 

78  84 

Fat                .       -4,,-  U  .;:.{ij.  :..-. 
Extractive  Matters       ".         *,'.. 
Mineral  substances         .    '    '» 

Chlorine         .         .         .         ,' 

1.72 
3.94 
8.55 

.       3.644 
0.115 

Extractive  Matters          .         .         .         2.60 
Mineral  substances  (exclusive  of  iron)     8.  12 

Chlorine         .         .         .         .         -       1.686 

Sulphuric  acid 

;       0.066 
1.134 

Phosphoric  acid     .         .       ^  ^ 
Potassium     •  .  .     • 

Sodium      "*    .  ''"  ,  ,  '  '  '  V  •     . 
Oxygen          .         .         .       ^;  .;:. 
Phosphate  of  Lime 
Phosphate  of  Magnesia     ..;,*;', 

.       0.191 
.       0.323 
.       3.341 
.       0.403 
.       0.311 
0.222 

Potassium 
Sodium 
Oxygen           .         . 
Phosphate  of  Lime 
Phosphate  of  Magnesia 

.       3.328 
.       1.052 

'".••    0.667 
.       0.114 
.       0.073 

From  this  we  see  that  not  only  do  the  Hsematin  and  Globulin  of  the  Corpus- 
cles replace  the  Fibrin  and  Albumen  of  the  Liquor  Sanguinis,  but  the  proportion 
of  Fat  in  the  former  is  considerably  greater  than  in  the  latter;  and  that 
although  the  whole  amount  of  mineral  matter  (excluding  the  iron  of  the  Hse- 
matin,  which  will  amount  to  1.17),  is  nearly  the  same  in  the  Corpuscles  as  in 
the  Liquor  Sanguinis,  yet  that  there  is  a  most  remarkable  and  significant  differ- 
ence in  i£s  constituents  in  the  two  cases  respectively.  For  while  the  Chlorine 
of  the  corpuscles  is  to  that  of  the  liq.  sang,  as  1  :  2.16,  the  Phosphoric  acid  of 
the  corpuscles  to  that  of  the  liq.  sang,  as  nearly  6:1;  and  whilst  the  Sodium 
of  the  corpuscles  is  to  that  of  the  liq.  sang,  as^l  :J5.3,  the  Potassium  of  the 
corpuscles  is  to  that  of  the  liq.  sang,  as  10.3  to  1.  Hence  it  is  obvious  that 
the  Chloride  of  Sodium  of  the  blood  must  be  principally  contained  within  the 
liquor  sanguinis,  whilst  the  Potash  of  the  blood  is  almost  wholly  included  in 
the  substance  of  the  corpuscles ;  and  from  the  excess  of  Phosphorus  in  the 
corpuscles  as  well  as  of  Fat,  it  may  be  fairly  concluded,  that  it  is  in  them  that 
the  peculiar  "  phosphorized  fats"  are  chiefly  formed.  These  facts  seem  to  sug- 
gest a  very  important  office  for  the  Red  Corpuscles,  which  is  in  harmony  with 
all  we  know  of  the  ratio  which  their  amount  in  different  animals  and  in  differ- 
ent individuals  of  the  Human  species,  bears  to  the  development  of  nervo-mus- 
cular  power  (§  194);  namely,  that  they  are  especially  concerned  in  preparing 
the  pabulum  for  the  Nervous  and  Muscular  tissues,  the  former  of  which  is  dis- 
tinguished by  the  presence  of  phosphorized  fats  (§  44),  and  the  latter  by  the 
remarkable  predominance  of  the  potash-salts  (§  85).  And  this1  view  derives 
further  confirmation  from  the  fact  that  a  flesh-diet  seems  to  have  a  decided  effect 
in  promoting  the  formation  of  the  red  corpuscles  (§  161). 4  The  Reel  Corpus- 
cles appear  to  have  a  remarkable  power  of  absorbing  certain  gases;  for  it  has 
been  found  by  Van  Maack  and  Scherer  that  a  solution  of  hsematin  possesses  a 
considerable  power  of  attracting  oxygen,  the  latter  of  these  chemists  having  also 
ascertained  that  after  the  absorption  of  oxygen  there  is  a  slight  development  of 
carbonic  acid;  whilst  it  has  been  proved  by  the  experiments  of  Davy,  Nasse, 
Scherer,  Magnus,  and  Lehmann  (see  Op.  cit.,  band  II.  p.  180),  that  the  capacity 

1  So  long  as  the  error  of  identifying  the  substance  of  Muscle  with  the  Fibrin  of  the 
Blood  prevailed  amongst  Chemists  and  Physiologists,  the  idea  stated  above  would  have  had 
little  weight;  but  now  that  we  know  that  no  special  relation-  between  them  exists  ($  25), 
we  are  free  to  attribute  the  source  of  the  Muscular  structure  to  whichever  component  of 
the  Blood  seems  most  likely  to  afford  it ;  and  in  the  absence  of  any  very  positive  distinc- 
tion between  the  composition  and  properties  of  Albumen  and  Globulin,  the  peculiar  rela- 
tion between  the  mineral  constituents  of  Muscle  and  those  of  the  Red  Corpuscles,  seems  to 
be  the  surest  guide  that  we  can  adopt. 
11 


162  OF   THE   BLOOD. 

of  defibrinated  blood  (i.  e.  of  serum + corpuscles)  for  absorbing  oxygen  and 
carbonic  acid,  is  much  greater  than  that  of  serum  alone,  being  at  least  twice  as 
much  for  equal  volumes.  Hence  it  seems  certain,  that  the  Red  Corpuscles 
must  contain  a  large  proportion  of  the  gases  of  the  blood  (§  163). 

143.  In  addition  to  what  has  been  already  stated  of  the  influence  of  water, 
saline  and  other  solutions,  and  acetic  acid,  upon  the  form  and  condition  of  the 
Red  Corpuscles,  the  following  facts  may  be  stated  with  regard  to  the  effects  of 
these  and  other  reagents.  According  to  Miiller,1  the  envelops  of  the  corpus- 
cles which  have  been  caused  to  burst  by  the  action  of  water,  remain  unchanged 
in  the  liquid  for  twenty-four  hours  or  more;  but,  after  remaining  for  some  days 
in  contact  with  it,  they  are  dissolved  by  it.  The  nuclei  of  the  nucleated  cor- 
puscles, however,  resist  its  solvent  action;  and  these  behave,  when  treated  with 
acids  and  alkalies,  as  fibrin  or  coagulated  albumen  would  do.  The  action  of 
acetic  acid  upon  the  wall  of  the  corpuscles  is  not  that  of  solution,  for  the  mem- 
brane is  still  distinguishable  as  a  delicate  film  around  the  nucleus,  and  may  be 
brought  into  more  obvious  view  by  tincture  of  iodine;  but  it  seems  to  occasion 
the  discharge  of  the  coloured  contents  of  the  vesicle,  either  by  causing  a  con- 
traction or  collapse  of  its  wall,  or  (more  probably)  by  augmenting  its  permea- 
bility. The  action  of  the  mineral  acids  upon  the  red  corpuscles  is  quite  differ- 
ent; for  these  occasion  a  coagulation  of  the  contents  of  the  cells  in  their  interior, 
so  that  they  are  no  longer  distended  by  water ;  and  this  without  producing  any 
other  change  of  shape  than  a  slight  corrugation.  Chlorine  and  alcohol  produce 
a  similar  effect.  On  the  other  hand,  the  corpuscles  are  entirely  dissolved  by 
the  mineral  alkalies  and  by  ammonia;  the  cell-walls  (and  nuclei)  disappearing 
completely,  and  the  cell-contents  being  diffused  through  the  solution.  Accord- 
ing to  Hunefeld  and  Simon,  the  walls  of  the  corpuscles  are  dissolved,  and  their 
contents  set  free,  when  they  are  treated  either  with  bile  or  with  ether ;.  it  is  also 
affirmed  by  Simon,  that  olive  oil  exerts  a  like  solvent  power;  and  Hunefeld 
states  that  pure  urea  causes  the  rupture  and  partial  solution  of  the  cell-walls 
and  the  dispersion  of  their  contents.2  (An  admixture  of  urine  with  the  blood 
seems  to  exert  no  other  influence  upon  the  corpuscles  than  a  saline  solution  of 
equal  density  would  do,  as  was  long  since  ascertained  by  Hewson.) — It  is 
affirmed  by  Lehmann,  however,  that  the  solution  of  the  walls  of  the  blood-cor- 
puscles is  rather  apparent  than  real;  for  that  in  very  few  cases  is  it  actually 
dissolved,  being  generally  transformed  into  a  mucous  or  gelatinous  condition,  in 
which  it  ceases  to  be  distinguishable,  in  consequence  of  its  co-efficient  of  refrac- 
tion being  the  same  with  that  of  the  plasma.  And  he  founds  this  conclusion, 
not  merely  upon  the  fact  that  the  capsule  is  often  made  visible  again,  either  in 
its  integral  state  or  in  fragments,  by  the  addition  of  tincture  of  iodine  or  of 
some  saline  solutions;  but  also  upon  the  viscid  and  glutinous  condition  of  the 
blood,  after  the  addition  of  dilute  organic  acids,  alkaline  carbonates,  iodide  of 
potassium  and  other  substances.  For  these  reagents  do  not  reduce  either  the 
liquor  sanguinis  or  the  serum  to  a  state  in  which  it  can  be  drawn  out  in  threads, 
and  hence  this  must  depend  upon  the  presence  of  the  corpuscles ;  whilst,  more- 
over, on  neutralizing  with  acids  or  with  alkalies  blood  which  has  been  thus 
changed,  or  on  adding  to  it  a  solution  of  iodine  or  sulphate  of  soda,  the  cell- 
walls  of  the  corpuscles  again  become  visible,  and  the  blood  loses  its  viscidity. 
It  is  further  remarked  by  Prof.  Lehmann,  that  some  of  the  Red  Corpuscles  re- 
sist the  influence  of  reagents  much  more  than  others  do;  and  he  infers  that  the 
latter  are  the  older  cells,  as  having  the  strongest  tendency  to  disintegration ; 

1  "Manuel  de  Physiologic,"  4ieme  edit.,  traduit  par  Jourdain,  torn.  i.  p.  92. 

2  See  Simon's  "Animal  Chemistry,"  translated  by  Dr.  Day,  pp.  97-100,  Am.  Ed.,  and 
Hunefeld  "Der  Chemismus  in  Thierischen  Organisation." 


ITS   PHYSICAL,    CHEMICAL,    AND   STRUCTURAL   CHARACTERS.      163 

whilst  those  which  present  an  unusual  resisting  power,  he  infers  to  be  young 
cells  which  have  not  yet  acquired  the  normal  characters  of  the  red  corpuscles.1 

144.  The  Red  Corpuscles,  when  freely  floating  in  the  Liquor  Sanguinis  of 
blood  no  longer  in  motion,  exhibit  a  marked  tendency  to  approximate  one  an- 
other; usually  coming  into  contact  by  their  flattened  surfaces,  so  that  a  number 
of  them  thus  aggregated  present  the  appearance  of  a  pile  of  coins;  or,  if  the 
stratum  be  too  thin  to  permit  them  to  lie  in  this  manner,  partially  overlapping 
one  another  or  even  adhering  by  their  edges,  which  then  frequently  become 
polygonal  instead  of  circular.     The  corpuscles,  when  thus  adherent,  resist  the 
influence  of  forces  which  tend  to  detach  them,  and  will  even  undergo  consider- 
able changes  of  shape,  rather  than  separate  from  each  other :  if  forced  asunder, 
however,  they  resume  their  normal  form.     After  thus  remaining  adherent  for  a 
time,  they  seem  to  lose  their  attractive  force ;  for  they  are  then  seen  to  separate 
from  each  other  spontaneously.    This  peculiar  tendency  to  aggregation  is  doubt- 
less one  of  the  circumstances  which  influences  the  coagulation  of  the  blood;  it 
is  most  strongly  manifested  in  inflammatory  blood,  and  assists  in  the  production 
of  the  buffy  coat  (§  189);  whilst,  on  the  other  hand,  it  seems  to  be  neutralized 
by  the  action  of  most  saline  substances,  since,  if  these  be  added  to  the  blood, 
the  corpuscles  do  not  run  together. 

145.  Besides  the  red  corpuscles  of  the  Blood,  there  are  others  which  possess 
no  colour  and  might  seem  to  have  a  function  altogether  different;  these  are 
known  as  the  White  or  Colourless  corpuscles  (Fig.  12,  c).     Their  existence  has 
long  been  recognized  in  the  blood  of  the  lower  Vertebrata,  where,  from  being 
much  smaller  than  the  red  corpuscle,  as  well  as  from  differing  widely  in  shape, 
they  could  readily  be  distinguished.     But  it  is  only  of  late  (chiefly  through  the 
researches  of  Gulliver,2  Addison,3  and  others),  that  they  have  been  recognized 
in  the  blood  of  Man  and  other  Mammalia;  their  size  being  nearly  the  same 
with  that  of  the  red  corpuscles;  and  the  general  appearance  of  the  two  (owing 
to  the  circular  form  of  the  latter,  and  the  absence  of  a  proper  nucleus),  being 
less  diverse.     It  is  remarkable  that,  notwithstanding  the  great  variations  in  the 
size  of  the  red  corpuscles  in  the  different  classes  of  Vertebrata,  the  dimensions 
of  the  colorless  corpuscles  are  extremely  constant  throughout;  their  diameter 
seldom  being  much  greater  or  less  than  l-3000th  of  an  inch  in  the  warm-blooded 
Vertebrata,  and  1 -2500th  of  an  inch  in  Reptiles.     This  holds  good  even  in  those 
animals — the  Musk-Deer,  and  the  Proteus — which  present  the  widest  departure 
from  the  general  standard  in  the  size  of  their  red  corpuscles;  so  that  the  color- 
less corpuscle  is  as  much  as  four  times  the  diameter  of  the  red,  in  one  instance ; 
whilst  it  is  not  one-eighth  of  the  long  diameter  of  the  red,  in  the  other. — The 
aspect  of  the  Colorless  corpuscles  under  the  microscope  is  by  no  means  constant ; 
but  their  variations  seem  to  depend  upon  their  degree  of  development,  and  all 
gradations  from  one  condition  to  another  may  be  readily  traced.     In  their  early 
state  (in  which  they  most  resemble  the  corpuscles  of  the  chyle  and  lymph),  the 
cell-membrane  can  scarcely  be  distinguished  from  the  large  nucleus  to  which  it 
is  applied,  unless  the  cell  be  distended  with  water  or  acetic  acid,  which  enables 
us  to  see  that  the  nucleus  is  a  soft,  granular,  tuberculated  mass,  which  is  dis- 
posed to  break  up  readily  into  two  or  more  fragments.     In  a  later  stage,  how- 
ever (of  those,  at  least,  which  do  not  go  on  to  be  developed  into  red  corpuscles) 
we  find  the  nucleus  apparently  dispersed  into  numerous  isolated  particles,  which 
give  to  the  entire  cell  a  somewhat  granular  and  tuberculated  aspect;  and  these 
particles  may  sometimes  be  seen  in  molecular  movement  within  the  cell.    When 
the  Colorless  corpuscles  are  treated  with  a  dilute  solution  of  potash,  they  speedily 

1  Op.  cit.,  band  ii.  p.  175. 

2  Notes  and  Appendix  to  Translation  of  "Gerber's  General  Anatomy." 

3  "Transactions  of  Provincial  Medical  Association,"  1842  and  1843. 


164 


OF   THE   BLOOD. 


burst  and  discharge  these  granules,  whose  molecular  movement  still  continues. 
The  Colorless  corpuscles  possess,  moreover,  a  higher  refracting  power  than  the 
red;  from  which  they  are  further  distinguished  by  their  greater  firmness,  and  by 
the  absence  of  any  disposition  to  adhere  to  each  other ;  so  that,  when  a  drop  of 
recent  blood  is  placed  between  two  strips  of  glass,  and  these  are  gently  moved 
over  one  another,  the  white  corpuscles  may  be  at  once  recognized  by  their  soli- 
tariness, in  the  midst  of  the  rows  and  irregular  masses  formed  by  the  aggrega- 
tion of  the  red.  This  is  still  better  seen  in  inflammatory  blood;  in  which  the 
Red  corpuscles  have  a  peculiar  tendency  to  adhere  to  one  another,  whilst  the 
White  are  commonly  present  in  unusual  number. 

146.  The  Colorless  corpuscles  may  be  readily  distinguished  in  the  circulat- 
ing Blood,  in  the  capillaries  of  the  Frog's  foot ;  and  it  is  then  observable  that 
they  occupy  the  exterior  of  the  current,  where  the  motion  of  the  fluid  is  slow, 
whilst  the  red  corpuscles  move  rapidly  through  the  centre  of  the  tube  (Fig.  13). 
The  Colorless  corpuscles,  indeed,  often  show  a  disposition   to  adhere  to  the 
walls  of  the  vessels ;  which  is  manifestly  increased  on  the  application  of  an 
irritant.    Hence  the  idea  naturally  arises,  that  (to  use  the  words  of  Mr.  Wharton 
Jones)  "  there  is  some  reciprocal  relation  between  the  colorless  corpuscles,  and 
the  parts  outside  the  vessels,  in  the  process  of  nutrition."     Of  the  nature  of 
this  relation  we  have  no  certain  knowledge ;  but  if  the  Red  corpuscles  discharge 
the  function  which  has  been  suggested  for  them  (§  142),  of  preparing  the  nu- 
trient material  for  Muscle  and  Nerve,  it  may  not  be  deemed  improbable  that 
the  Colorless  corpuscles  should  perform  a  similar  office  for  the  other  albuminous 
tissues. — A  very  remarkable  spontaneous  change  of  form  has  been  observed  by 
Mr.  Wharton  Jones  to  take  place  in  the  Colorless  corpuscles  whilst  being  ex- 
amined under  the  microscope;1  and  this 
not  only  in  the  blood   of  Man,  but  in 
that  of  animals  of  all  the  Vertebrated 
classes,  as  also  in  that  of  Invertebrata, 
whose  only  corpuscles  are  of  this  charac- 
ter (§  147).     From  some  point  of  their 
circumference  a  protrusion   of  the  cell- 
wall  takes  place,  the  form  of  which  seems 
quite  indefinite ;  soon  afterwards,  another 
protrusion  may  be  seen  to  arise  from  ano- 
ther part  of  the  cell,  the  first  being  either 
drawn  in  again,  or  remaining  as  it  was; 
and  thus  the  configuration  of  the  corpus- 
cles  may  be   seen   to    undergo   several 
changes  before  the  process  finally  ceases, 
and  this  whilst  they  are  floating  in  their 
own  serum,  and-  the  red  corpuscles  are 
lying  quite  passive  in  their  immediate 
vicinity.     These  changes  of  form,  which 
bear  a  striking  resemblance  to  those  of  the 
Proteus-cell,  already  referred  to  (§  109), 
are  affirmed  by  Dr.  Davaine  (by  whom 
they  have  been  more  recently  studied)  to 
be  visible  even  whilst  the  blood  is  circu- 
lating through  the  vessels,  in  those  colorless  corpuscles  which  are  retarded  by 
attraction  to  their  walls.3 

147.  The  proportion  which  the  White  or  Colorless  corpuscles  bear  to  the  m 


A  small  venous  trunk,  a,  from  the  Web-of  the 
Frogs  foot,  magnified  350  Diameters ;  b,  b,  cells 
of,  pavement-epithelium,  containing  nuclei.  In 
the  space  between  the  current  of  oval  Blood-cor- 
puscles, and  the  walls  of  the  vessel,  the  round 
transparent  white  corpuscles  are  seen. 


1  "Philosophical  Transactions,"  1846,  pp.  64,  71,  90,  &c. 

2  "Memoires  de  la  Societe  de  Biologic,"  torn,  ii  pp.  103-5. 


ITS   PHYSICAL,    CHEMICAL,    AND    STRUCTURAL   CHARACTERS.      165 

Red,  is  very  small  in  the  blood  of  Man  and  the  higher  Vertebrata ;  being,  in 
the  state  of  health,  not  more  than  1  :  50.  It  may  undergo  a  great  increase  in 
disease,  however,  as  will  be  shown  hereafter  (§175).  In  the  oviparous  Verte- 
brata, the  proportion  is  higher ;  thus  it  has  been  observed  by  Wagner1  to  be  as 
1  :  16  in  the  blood  of  a  Frog  examined  in  February,  and  as  1  :  6  in  similar 
blood  examined  in  August.  In  one  vertebrated  animal,  the  Amphioxus,  the 
Red  corpuscles  are  wanting  altogether,  their  place  in  the  circulating  blood  being 
taken  by  the  Colorless.  And  in  the  Invertebrate  series  generally,  the  corpus- 
cles of  the  circulating  fluid  correspond  rather  to  the  colorless  corpuscles  of  the 
Blood  of  Vertebrata,  and  to  the  corpuscles  of  Lymph  and  Chyle  (which  may  be 
regarded  as  the  same  bodies  in  an  earlier  stage  of  development),  than  they  do 
to  the  red  corpuscles,  which  are  peculiar  to  Vertebrata.3  Thus,  in  one  of  its 
most  characteristic  features,  the  Blood  of  Invertebrata  (and  of  Amphioxus) 
may  be  likened  rather  to  the  Lymph  and  Chyle  of  Vertebrated  animals,  than 
to  their  Blood ;  and  this  resemblance  is  strengthened  by  the  fact,  that  there  is 
no  distinction  in  the  former  between  the  absorbent  and  the  sanguiferous  vessels, 
which,  in  the  latter,  contain  the  nutritious  fluid  in  its  earlier  and  its  later  stages 
of  development.  Moreover,  the  earliest  blood-corpuscles  of  the  embryo  of  even 
the  highest  Vertebrata  are  colorless ;  and  long  after  the  blood  has  acquired  its 
characteristic  hue  from  the  development  of  red  corpuscles,  the  colorless  corpus- 
cles bear  a  very  large  proportion  to  the  red,  so  as  even  to  equal  them  in  num- 
ber (as  the  author  is  informed  by  Mr.  Gulliver)  in  the  blood  of  foetal  Deer  an 
inch  and  a  half  long,  and  absolutely  preponderating  in  the  blood  of  still  smaller 
embryos. 

.148.  There  can  be  no  doubt  that  both  the  Red  and  the  Colorless  corpuscles 
have,  like  other  cells,  a  definite  term  of  life ;  and  that,  whilst  some  are  under- 
going disintegration,  others  are  in  a  state  of  advancing  development  to  supply 
their  places,  so  that  the  entire  mass  of  both  is  undergoing  continual  change. 
That  a  new  production  of  Red  corpuscles  may  take  place  with  considerable  ra- 
pidity, we  have  evidence  in  the  restoration  of  their  normal  proportion  after  it 
has  been  lowered  by  hemorrhage  (§  162),  and  in  the  speedy  increase  which  may 
be  effected  in  their  amount  in  blood  in  which  they  have  been  excessively  dimin- 
ished by  disease  (§  174) ;  this  being  especially  promoted  by  the  administration 
of  Iron,  and  by  a  generous  diet.  On  the  other  hand,  various  appearances  indi- 
cative of  degeneration  may  be  seen  in  the  Red  corpuscles ;  and  this  especially 
in  the  blood  of  the  Oviparous  Vertebrata,  which  usually  contains  corpuscles 
almost  destitute  of  color,  and  of  shrunken  or  eroded  aspect,  their  nuclei,  however, 
presenting  a  remarkable  distinctness.  The  question  now  arises,  in  what  manner 
the  two  classes  of  Corpuscles  are  respectively  developed,  and  whether  they  have 
any  relationship  to  each  other. 

149.  That  the  fully-developed  Red  corpuscles,  when  ceasing  to  exist  as  such, 
do  not  give  origin  to  new  corpuscles  of  the  same  kind,  may  now  be  asserted 
(notwithstanding  the  statements  of  former  observers)  to  be  the  concurrent 
opinion  of  nearly  all  who  have  in  recent  times  specially  devoted  themselves  to 
this  inquiry  ;  for  although  they  may  occasionally  be  seen  to  undergo  duplicative 
subdivision  (§  104),  yet  this  multiplication  only  takes  place  at  an  early  period 
of  their  development.  The  first  Red  corpuscles  unquestionably  have  their 
origin,  like  the  original  cells  of  the  solid  tissues,  in  the  primordial  cells  of  the 
germinal  structure ;  and  it  is  in  the  so-called  "  vascular  layer"  of  the  "  blasto- 
dermic  vesicle"  (CHAP,  xix.),  and  in  the  mass  of  cells  which  constitutes  the 

1  "Elements  of  Physiology,"  translated  by  Dr.  Willis,  p.  246. 

2  See  Mr.  Wharton  Jones's  Memoir  on  "the  Blood-Corpuscle  considered  in  its  different 
Phases  of  Development  in  the  Animal  Series,"  in  the  "  Philos.  Trans.,"  1846 ;  also  "  Princ. 
of  Gen.  and  Comp.  Phys.,"  %  567,  Am.  Ed. 


166  OP   THE   BLOOD. 

rudiment  of  the  heart,  that  this  metamorphosis  seems  first  to  take  place.  The 
situation  of  the  heart,  and  the  course  of  the  principal  trunks  of  the  "vascular 
area,"  are  early  marked  out  by  the  peculiar  disposition  of  the  aggregations  of 
cells  from  which  these  organs  are  to  be  developed ;  and  whilst  the  outer  portions 
of  these  aggregations  are  transformed  into  the  walls  of  the  respective  cavities, 
the  inner  portions  seem  partly  to  deliquesce,  and  partly  to  remain  as  isolated 
cells  floating  in  the  liquid  thus  produced.  These  isolated  cells  are  the  first 
blood-corpuscles ;  and  the  following  account  of  them  is  given  by  Mr.  Paget,1 
who  has  made  them  the  subject  of  careful  study.  "  As  described  by  Vogt, 
Kolliker,  and  Cramer,  they  are  large  colorless  vesicular  spherical  cells,  full  of 
yellowish  particles  of  a  substance  like  fatty  matter  (Fig.  14,  A)  j  many  of  which 
particles  are  quadrangular  and  flattened,  and  have  been  called  stearine-plates, 

Fig.  14. 


Development  of  the  first  set  of  red  corpuscles  in  the  blood  of  the  Batrachian  larva.  A.  An  embryo-cell,  filled 
•with  fatty-looking  particles.  B,  c,  D,  and  E.  Successive  stages  in  the  transition  of  the  embryo-cell  to  a  blood- 
corpuscle,  as  described  in  the  text.  F.  A  fully-formed  blood-corpuscle. 

though  they  are  not  proved  to  consist  of  that  or  any  other  unmixed  fatty  sub- 
stance. Among  these  particles  each  cell  has  a  central  nucleus,  which,  however, 
is  at  first  much  obscured  by  them.  The  development  of  these  embryo-cells  into 
the  complete  form  of  the  corpuscles  is  effected  by  the  gradual  clearing-up,  as  if 
by  division  and  liquefaction,  of  the  contained  particles,  the  acquirement  of  blood- 
color  and  of  the  elliptical  form,  the  flattening  of  the  cell,  and  the  more  promi- 
nent appearance  of  the  nucleus/'  The  process  appears  to  be  essentially  the 
same  in  the  Fish,  the  Reptile,  and  the  Bird ;  but  it  takes  place  too  rapidly  in 
the  latter  class  for  its  stages  to  be  clearly  distinguished ;  whilst  in  the  tadpole 
the  changes  occur  so  slowly  that  they  can  be  traced  in  the  blood  even  while  it 
circulates. — The  history  of  the  development  of  the  first  red  corpuscles  in  Mam- 
malia is  nearly  the  same ;  but  a  binary  multiplication  of  these  bodies  by  sub- 
division has  been  observed  in  them,  which  has  not  been  noticed  elsewhere  (Fig. 
15,  A,  D).  In  watching  the  stages  of  this  process,  it  is  seen  that  the  partition 
of  the  nucleus  takes  place  completely,  before  that  of  the  cell  itself  has  com- 
menced.— The  blood-corpuscles  of  the  Human  embryo  thus  formed,  are  de- 
scribed by  Mr.  Paget  as  "  circular,  thickly  disk-shaped,  full-colored,  and,  on  an 
average,  about  ^ -2500th  of  an  inch,  in  diameter;  their  nuclei,  which  are  about 
l-5000th  of  an  inch  in  diameter,  are  central,  circular,  very  little  prominent 
on  the  surfaces  of  the  cell,  and  apparently  slightly  granular  or  tuberculated. 
In  a  few  instances,  cells  are  found  with  two  nuclei ;  and  such  cells  are  usually 
large  and  elliptical,  with  one  of  the  nuclei  near  each  end  of  the  long  axis." 

1  This  account  is  cited  from  Messrs.  Kirkes  and  Paget's  "Manual  of  Physiology,"  (pp. 
62-6,  Am.  Ed.,]  in  which  it  appears  as  an  abstract  of  a  part  of  Mr.  Paget's  Lectures  on 
the  "  Life  of  the  Blood,"  delivered  at  the  College  of  Surgeons  in  1848. 


ITS   PHYSICAL,    CHEMICAL,   AND    STRUCTURAL   CHARACTERS.       167 

This  first  brood  of  red  corpuscles  soon  disappears,  when  the  lymph  and  chyle 
begin  to  be  poured  into  the  blood,  being  superseded  by  those  developed  from  the 
corpuscles  brought  in  by  them ;  and  this  epoch  generally  corresponds  closely 
with  the  alteration  in  the  embryonic  circulation,  which  consists  in  the  oblite- 

Fig.  15. 


Development  of  the  first  set  of  red  corpuscles  in  the  Wood  of  the  Mammalian  emhryo.  A.  A  dotted,  nu- 
cleated embryo-cell,  in  process  of  conversion  into  a  blood-corpuscle :  the  nucleus,  provided  with  a  nucleolus. 
B.  A  similar  cell  with  a  dividing  nucleus;  at  c,  the  division  of  the  nucleus  is  complete;  at  D,  the  cell  also  is 
dividing.  E.  A  blood-corpuscle  almost  complete,  but  still  containing  a  few  granules,  r.  Perfect  blood-cor- 
puscles. 

ration  of  the  branchial  arches  (CHAP.  xix.).  In  the  Human  embryo,  the  first 
set  of  corpuscles  seems  to  disappear  entirely  by  the  end  of  the  second  month, 
except  in  cases  of  arrested  development. 

150.  The  doctrine  that  the  continued  generation  of  Red  corpuscles  is  due  to 
the  metamorphosis  of  the  Chyle-  and  Lymph-corpuscles,  the  Colorless  corpuscles 
of  the  Blood  constituting  an  intermediate  stage  of  development,  is  one  which 
has  come  of  late  to  be  very  generally  received  amongst  Physiologists ;  it  may 
be  found,  however,  to  require  some  modification.  It  rests  upon  facts  of  three 
different  orders  :  1st,  the  presence,  in  all  ordinary  Blood,"of  corpuscles  exhi- 
biting what  appear  to  be  intermediate  gradations  of  development  between  the 
Lymph-corpuscle  and  the  true  Red  corpuscle ;  and  this  especially  in  blood  in 
which  an  unusually  rapid  development  of  red  corpuscles  is  taking  place,  to  make 
up  for  previous  loss ;  2d,  frequent  ruddiness  in  the  hue  of  the  fluid  of  the  Tho- 
racic duct,  which  seems  to  depend  upon  the  incipient  development  of  Haematine 
in  some  of  its  floating  corpuscles ;  and  3d,  the  progressive  transition  from  one 
form  to  the  other,  which  may  be  observed  in  the  ascending  scale  of  animal 
existence.  To  these  considerations  may  be  added,  the  absence  of  any  other 
mode  of  production  that  can  be  suggested ;  since  the  idea  of  the  self-multiplica- 
tion of  the  Red  corpuscles  is  almost  certainly  erroneous,  and  no  special  organ 
can  be  assigned  as  the  seat  of  their  generation.1 — The  transition-stages  between 

1  According  to  the  observations  of  Weber  ("Henle  and  Pfeufer's  Zeitschrift,"  1846, 
and  "Canstatt's  Jahresbericht,"  1848),  the  Liver  of  oviparous  animals  appears  to  assist 
in  the  production  of  the  Red  corpuscles,  from  the  materials  furnished  by  the  yolk,  during 
the  latter  part  of  intra-oval  life,  in  the  Frog  and  in  the  Chick.  In  the  Mammal,  however, 
the  contents  of  the  yolk-bag  (or  umbilical  vesicle)  are  exhausted  at  a  very  early  period  of 
embryonic  life,  when  as  yet  the  liver  is  rudimentary ;  so  that  if  this  organ  takes  any  share 
in  the  development  of  red  corpuscles,  it  can  only  perform  such  a  function  for  a  very  brief 
time.  At  no  subsequent  period  is  there  any  evidence  that  the  Liver  is  concerned  in  the 
development  of  Red  corpuscles;  and  although  the  Spleen  has  been  supposed  to  act  as  their 
matrix,  yet  all  the  evidence  at  present  in  our  possession  shows  that  neither  to  this  nor  to 
,  any  other  of  the  "vascular  glands"  can  such  a  function  be  justly  assigned  (g  172). 


168  Or   THE   BLOOD. 

the  White  and  the  Red  corpuscle  are  thus  described  by  Mr.  Paget1  as  they  are 
seen  in  Human  blood.  "  The  white  corpuscle,  at  first  tuberculated,  containing 
many  granules,  and  darkly  shaded  (Fig.  16,  A),  becomes  smoother,  paler,  less 
granular,  and  more  dimly  shaded  or  nebulous  (B).  In  these  stages  the  cell- 
wall  may  be  easily  raised  from  its  contents  by  the  contact  and  penetration  of 
acetic  acid,  or  by  the  longer  action  of  water  (c) ;  and,  according  to  the  stage  of 


Development  of  human  lymph  and  chyle  corpuscles  into  red  corpuscles  of  Blood.  A.  A  lymph,  or  -white 
blood-corpuscle.  B.  The  same,  in  process  of  conversion  into  a  red  corpuscle,  c.  A  lymph-corpuscle,  with  the 
cell-wall  raised  up  round  it  hy  the  action  of  water.  D.  A  lymph-corpuscle,  from  which  the  granules  have 
almost  all  disappeared.  E.  A  lymph-corpuscle,  acquiring  color ;  a  single  granule,  like  a  nucleus,  remains.  F. 
A  red  corpuscle,  fully  developed. 

development,  so  are  the  various  appearances  which  the  contents  of  the  cell  thus 
acted  on  present.  In  the  regular  progress  of  development,  it  becomes  at  length 
impossible  to  raise  the  cell-wall  from  its  contents  (D).  Then  the  corpuscles 
acquire  a  pale  tinge  of  blood-color;  and  this  always  coincides  with  the  softening 
of  the  shadows  which  before  made  them  look  nebulous,  and  with  the  final 
vanishing  of  all  the  granules,  with  the  exception  sometimes  of  one,  which  re- 
mains some  time  longer  like  a  shining  particle  in  the  corpuscle,  and  has  proba- 
bly been  often  mistaken  for  a  nucleus  (E).  The  blood-color  now  deepens,  and 
at  the  same  rate  the  corpuscles  become  smooth  and  uniform ;  biconcave,  having 
previously  changed  the  nearly  spherical  form  for  a  lenticular  or  flattened  one ; 
smaller,  apparently  by  condensation  of  their  substance,  for  at  the  same  time 
they  become  less  amenable  to  the  influence  of  water ;  more  liable  to  corrugation 
and  to  collect  in  clusters;  and  heavier,  so  that  the  smallest  and  fullest-colored 
corpuscles  always  lie  deepest  in  the  field  (F).  Thus  the  most  developed  state 
of  the  Mammalian  red  corpuscles  appears  to  be  that  in  which  they  are  full- 
colored,  circular,  biconcave,  small,  uniform,  and  heavy;  this  is  also  the  state  in 
which  they  appear  to  live  the  longer  and  most  active  portion  of  their  lives. " — 
Thus,  then,  the  lymph  and  chyle  seem  to  be  continually  supplying,  not  merely 
the  pabulum  for  organization  derived  from  the  food,  but  an  important  kind  of 
organized  bodies,  the  existence  of  which  in  the  blood  is  essential  to  the  well- 
being  of  the  entire  system ;  and  this  view  is  confirmed  by  the  fact,  that  the 
fluid,  not  only  of  the  thoracic  duct,  but  also  of  the  larger  lymphatics,  frequently 
possesses  a  roseate  hue  (which  sometimes  makes  itself  apparent  in  the  horse 
even  through  the  walls  of  the  thoracic  duct),  and  that  this  is  attributable  to  the 
presence  in  it  of  corpuscles  which  seem  to  be  in  process  of  transformation  into 
the  Red  corpuscles  of  the  blood,  being  smaller,  paler,  and  less  perfect  in  shape.3 

1  "Manual  of  Physiology,"  pp.  65-6,  Am.  Ed. 

2  See  Mr.  Gulliver's  observations,  in  his  edition  of  '-Hewson's  Works,"  p.  276,  and  in 
the  Translation  of  "Gerber's  General  Anatomy,"  p.  93. 


ITS   PHYSICAL,    CHEMICAL,    AND    STRUCTURAL   CHARACTERS.       169 

— Lastly,  the  correspondence  pointed  out  by  Mr.  Wharton  Jones  (loc.  cit.),  be- 
tween the  successive  phases  presented  by  the  Blood-corpuscles  in  the  animal 
series,  and  those  through  which,  according  to  the  views  above  stated,  the  Red 
corpuscle  passes  in  attaining  its  complete  form  in  the  highest  animal,  is  really 
extremely  close.  For  in  the  blood  of  the  Invertebrata,  as  in  the  chyle  and 
lymph,  and  occasionally  in  the  blood  of  Yertebrata,  are  found  "  coarse  granule- 
cells,"  which  seem  to  be  in  the  first  stage  of  development,  and  "fine  granule-cells/' 
which  may  be  regarded  as  in  the  second.  This  leads  on  to  the  "  colorless  nucle- 
ated cell/'  which  is  the  highest  form  presented  by  the  corpuscles  in  Invertebrated 
animals,  but  is,  as  we  have  seen,  a  mere  transitional  stage  of  brief  duration  in 
those  of  Vertebrata.  The  "colored  nucleated  cell,"  again,  is  the  highest  form 
of  red  corpuscle  in  the  Oviparous  Vertebrata ;  and  this  corresponds  with  a 
more  advanced  stage  of  development  in  the  red  corpuscle  of  Mammalia.  The 
"  colored  non-nucleated  cells"  of  the  latter  are  to  be  regarded  as  exhibiting  that 
highest  phase  of  development,  in  which  the  nucleus  disappears,  apparently  in 
virtue  of  the  completion  of  its  formative  office,  and  of  its  resolution  into  the 
fluid  contents  of  the  cell. 

151.  Notwithstanding  the  strength  of  the  foregoing  evidence,  yet  there  are 
certain  considerations  which  render  it  difficult  to  give  an  unreserved  adhesion  to 
this  doctrine  of  the  transformation  of  the  chyle-  and  lymph-corpuscles  into  the 
red  corpuscles  of  the  blood,  through  the  intermediate  grade  of  the  white.  For 
although  the  correspondence  in  size  between  the  lymph-globule,  the  colorless 
blood-corpuscle,  and  the  red  corpuscle,  is  so  close  in  Man  as  to  sanction  this  idea 
of  their  relationship,  yet  no  such  correspondence  exists  elsewhere ;  for  we  find 
that,  as  the  diameter  of  the  lymph-globules  and  of  the  white  blood-corpuscles 
remains  pretty  constant,  whilst  that  of  the  red  presents  a  wide  range  of  variation 
in  different  animals,  there  comes  to  be  a  strongly-marked  disproportion  between 
them;  the  lymph-globules  of  the  Musk-deer,  for  example,  being  of  the  usual 
size,  whilst  the  diameter  of  the  red  corpuscles  is  less  than  1-12, 000th  of  an  inch, 
or  no  more  than  a  quarter  of  the  preceding;  the  lymph-globules  of  oviparous 
Vertebrata  being  usually  of  no  larger  diameter  than  the  nuclei  of  their  red  cor-  • 
puscles,  and  where  (as  in  the  Perennibranchiate  Batrachia)  the  red  corpuscles 
are  of  enormous  size,  having  even  a  far  less  diameter  than  their  nuclei.  The 
form  of  the  lymph-globules  and  of  the  colorless  corpuscles,  moreover,  is  always 
circular;  yet  that  of  the  red  corpuscles  and  of  their  nuclei  is  oval  in  all  the 
oviparous  Vertebrata,  the  ratio  between  the  long  and  the  short  diameters  of  the 
corpuscles  being  frequently  as  2:1,  and  between  the  diameters  of  the  nuclei 
being  sometimes  as  3.3  : 1.  Hence  until  it  shall  have  been  shown  how  these 
differences  are  obliterated  in  the  course  of  the  developmental  process — how  the 
lymph-globule  of  the  Musk-deer  either  contracts  or  subdivides,  so  as  to  form  a 
blood-corpuscle  of  one-sixteenth  of  its  area — and  how  the  round  lymph-globule 
of  the  Proteus  swells  out  into  an  oval  cell  of  thirty  or  forty  times  its  dimensions, 
— the  proof  must  be  considered  as  far  from  complete.  And  even  if  it  be  admitted 
that  the  red  corpuscle  is  originally  developed  from  the  lymph-globule,  and  that 
this  is  also  the  source  of  the  colorless  corpuscle,  still  it  would  seem  quite  possible, 
that  the  Red  and  the  Colorless  corpuscles  are  to  be  regarded  as  two  distinct  and 
complete  forms,  neither  being  capable  of  metamorphosis  into  the  other,  and  each 
having  a  specific  purpose  to  serve  in  the  economy.  For,  so  far  as  can  be  judged 
by  appearances,  there  is  a  close  correspondence  between  the  Colorless  corpuscles 
and  the  corpuscles  of  those  "  Vascular  Glands"  which  are  developed  in  connection 
with  the  Absorbent  and  Sanguiferous  systems,  and  which  seem  to  have  it  for 
their  office  to  assist  in  elaborating  the  nutrient  materials  of  the  blood  (CHAP. 
VIII.  SECT.  3).  And  there  are  many  indications,  as  will  hereafter  appear,  that 
their  function  is  not  dissimilar;  whilst,  on  the  other  hand,  there  is  no  corre- 


170 


OF   THE   BLOOD. 


spondence  between  the  Red  and  the  Colorless  corpuscles,  either  as  to  their  pro- 
portionate development  or  as  to  their  relations  to  the  system  generally  in  health 
and  disease  (§§  174,  175). — It  may  be  surmised,  then,  that  if  the  principal  part 
of  the  lymph-globules  really  go  on  to  be  developed  into  Red  corpuscles,  a  part 
may  undergo  a  different  course  of  evolution  and  become  Colorless  corpuscles  of 
the  blood;  and  that,  having  once  acquired  the  latter  condition,  they  do  not  pass 
beyond  it,  but  continue  to  present  it  during  their  remaining  term  of  life.  Such 
a  diverse  mode  of  evolution  from  germs  that  appear  to  be  similar,  cannot  be 
thought  in  itself  improbable,  when  it  is  borne  in  mind  that  all  the  tissues  have 
their  origin,  directly  or  indirectly,  in  the  cells  of  the  embryonic  mass,  among 
which  not  the  slightest  difference  can  be  observed ;  and  that,  whatever  is  to  be 
the  ultimate  destination  of  cells  at  any  period  of  life,  their  early  aspect  is  for 
the  most  part  extremely  uniform. 

152.  Composition  of  the  Blood. — The  principal  components  of  the  Blood 
having  been  thus  separately  described,  we  have  now  to  inquire  into  the  mode  in 
which  they  are  associated  in  the  liquid  as  a  whole,  and  the  proportions  in  which 
they  severally  present  themselves.  These  are  subject,  even  within  the  limits 
of  health,  to  considerable  variations ;  some  of  which  seem  to  depend  upon  the 
constitution  of  the  individual,  his  diet,  mode  of  life,  &c. ;  whilst  others  are  pro- 
bably referable  to  the  period  at  which  the  last  meal  was  taken,  and  the  amount 
of  bodily  exertion  made  within  a  short  time  previous  to  the  analysis.  When 
the  results  obtained  by  different  experimenters,  moreover,  are  brought  into  com- 
parison, a  very  marked  discrepancy  is  frequently  found  amongst  them,  especially 
in  regard  to  the  relative  proportions  of  albumen  and  corpuscles ;  and  this  arises 
in  great  degree  from  the  difference  of  the  methods  of  analysis  employed,  as  has 
been  recently  proved  by  M.  Grorup-Besanez.1  For  he  found  that  when  four 
samples  of  the  same  blood  were  examined  by  the  methods  adopted  by  four  dif- 
ferent experimenters  respectively,  the  results  were  as  follows. 

The  first  specimen  was  the  blood  of  a  vigorous  man  fifty  years  old : 


Becquerel 


Gorup- 


Water 
Solid  matters 

Scherer. 
796.93 
203.07 

and  Kodier. 
796.93 

203.07 

Hofle. 
796-93 
203.07 

Besanez. 
796.93 
203.07 

Fibrin 
Corpuscles  . 
Albumen 
Extractive  matter 

s  and 

salts 

1.95 
115.16 

58.82 
27.14 

1.95 
117.82 

63.87 
19.43 

1.95 
103.23 

50.84 
47.05 

1.95 
103.23 
70.75 
27.14 

The  second  specimen  was  from  a  robust  man  twenty  years  old : — 


Scherer. 

Becquerel 
and  Kodier. 

Hofle. 

Gorup- 
Besanez. 

Water          .                                783.63 

783.63 

783.63 

783.63 

Solid  matters 

216.37 

216.37 

216.37 

216.37 

Fibrin 

1.56 

1.56 

1.56 

1.56 

Corpuscles  . 

113.54 

131.52 

115.12 

115.12 

Albumen 

64.32 

65.91 

51.76 

62.74 

Extractive  matters  and  salts        36.95 

17.38 

47.93 

36.95 

Hence  it  is  of  no  value  whatever  to  bring  together  analyses  made  by  different 
methods,  since  no  reliance  can  be  placed  on  the  results  of  their  comparison ;  and 
in  estimating  the  alterations  which  present  themselves  in  morbid  conditions  of 
the  blood,  it  is  of  course  of  fundamental  importance,  that  we  should  take  as  our 
standard  an  average  of  analyses  of  healthy  blood  made  by  the  same  method.  As 


Journ.  fur  prakt.  Chem.,"  band  1.  p.  346. 


ITS    PHYSICAL,    CHEMICAL,    AND    STRUCTURAL    CHARACTERS.       171 

the  greater  number  of  results  hereafter  to  be  cited  have  been  obtained  by  the 
method  of  MM.  Andral  and  Gavarret,1  which  has  been  followed,  with  slight 
modifications,  by  MM.  Becquerel  and  Rodier,2  it  will  be  advantageous  here  to 
describe  it. — The  blood  which  is  being  drawn  for  analysis  is  received  into  two 
different  vessels,  the  first  and  the  last  quarters  of  the  whole  amount  into  one,  and 
the  second  and  third  quarters  into  the  other;  in  this  manner  the  similarity  of 
the  two  quantities  is  secured  as  far  as  possible.  The  blood  in  one  vessel  (A)  is 
allowed  to  coagulate  spontaneously ;  that  contained  in  the  other  (B)  is  beaten 
with  a  small  rod  in  order  to  separate  the  fibrin.  When  the  coagulation  has  fully 
taken  place  in  A,  the  serum  is  carefully  separated  from  the  crassamentum ;  and 
there  are  then  dried  and  weighed — 1.  The  Fibrin  obtained  by  the  rod  (B); — 2. 
The  entire  Crassamentum  (A)  ; — 3.  The  Serum  (A).  The  weight  of  the  separated 
fibrin  gives  the  amount  of  it  contained  in  the  clot.  The  weight  of  the  dried 
residue  of  the  serum  gives  the  proportion  of  its  solid  matter  to  its  water.  The 
quantity  of  water  driven  off  from  the  clot  in  drying  gives  the  amount  of  serum 
it  contained ;  from  which  may  be  estimated  the  quantity  of  the  solids  of  the 
serum  contained  in  the  crassamentum.  Hence  by  deducting  from  the  weight  of 
the  whole  dried  clot,  first  the  weight  of  the  fibrin  separated  by  stirring,  and  then 
that  of  the  solid  matter  of  the  serum  as  obtained  by  calculation,  we  obtain  as  a 
residue  the  weight  of  the  corpuscles.  In  order  to  ascertain  the  whole  amount  of 
solid  matter  in  the  serum,  that  which  was  ascertained  by  calculation  to  exist 
in  the  coagulum  must  be  added  to  that  which  was  obtained  from  the  separated 
serum.  Finally,  the  proportion  of  organic  and  of  inorganic  matter  in  the  solids  of 
the  serum  is  ascertained  by  incinerating  them  in  a  crucible  ;  by  which  the  whole 
of  the  former  will  be  driven  off,  the  latter  being  left. 

153.  A  modification  of  this  method,  which  involves  somewhat  more  trouble 
in  its  application,  but  which  is  more  accurate,  has  been  recently  proposed  by 
Scherer.3  The  blood  is  received,  as  before,  into  two  separate  vessels;  and  in 
both  of  these,  which  are  covered  to  prevent  evaporation,  coagulation  is  allowed 
to  take  place.  Out  of  the  one  (A)  is  to  be  determined  the  composition  of  the 
serum,  and  from  the  other  (B)  that  of  the  remaining  constituents.— Two  weighed 
portions  of  the  serum  are  taken  from  the  first  vessel  (A),  and  one  of  them  is 
evaporated  until  all  the  water  is  driven  off;  the  residue  then  represents  the 
entire  solid  matter  of  the  serum.  This,  having  been  weighed,  is  incinerated ; 
and  the  residue  then  left  is  the  saline  matter  of  the  serum.  The  other  portion 
of  the  serum  is  poured  into  boiling  water,  and  stirred  with  a  glass  rod,  acetic 
acid  being  added,  drop  by  drop,  as  long  as  any  precipitation  continues.  The 
albuminous  coagulum  is  then  separated  by  filtration,  dried  and  weighed ;  and 
the  filtered  fluid,  after  being  again  examined  for  any  albumen  that  may  be  left 
uncoagulated,  is  evaporated  to  dryness.  The  residue,  consisting  of  the  extractive 
with  the  salts,  is  incinerated  after  having  been  weighed ;  and  the  weight  of  the 
salts  being  thus  determined,  the  difference  is  that  of  the  extractive  matters. — 
The  blood  in  the  second  vessel  (B),  after  having  been  weighed,  is  put  upon  a  fine 
linen  cloth,  and  carefully  squeezed  between  the  fingers  until  all  the  fluid  is 
expressed  that  can  be  thus  separated,  and  only  the  solid  coagulum  remains 
behind ;  this  is  well  washed  with  distilled  water,  to  get  rid  of  the  corpuscles, 
and  the  fibrinous  residue  is  dried  and  weighed.  Of  the  expressed  fluid  (serum + 
corpuscles)  two  portions  are  again  weighed  out,  as  of  the  serum  alone  in  the 
previous  analysis;  one  of  these  serves  to  determine  the  relative  proportions  of 
the  water,  of  the  solid  residue,  and  of  the  salts;  and  the  other  to  determine  the 

1  "  Essai  d'Haematologie  Pathologique." 

2  "  Recherches  sur  la  Composition  du  Sang,  dans  1'etat  de  Sante,  et  dans  1'etat  de 
Maladie." 

3  "Canstatt's  Jahresbericht,"  1848,  p.  64;  and  Haeser's  Archiv.,  band  x.  p.  191. 


172  OF   THE   BLOOD. 

coagujable  proportion  of  the  Albumen  and  Corpuscles,  the  coagulation  being 
induced  as  before,  and  the  filtered  residue  again  serving  for  the  determination 
of  the  extractive  and  soluble  salts. — The  fatty  matters  may  be  determined  by 
boiling  in  ether,  for  a  sufficient  length  of  time,  portions  of  the  fibrin,  of  the 
albumen,  and  of  the  coaguluin  of  the  whole  blood,  separately. — In  summing  up 
the  result,  the  amount  of  the  various  solid  matters  is  calculated  for  1000  parts 
of  Blood ;  the  remainder  is  then  the  watery  part  of  the  blood.  From  the  propor- 
tion of  albumen  to  water  in  the  serum,  the  amount  of  albumen  in  the  whole  mass 
of  the  blood  can  be  calculated  by  its  quantity  of  water;  and  the  amount  of  albu- 
men and  corpuscles  taken  together  having  been  determined,  that  which  remains 
after  the  deduction  of  the  albumen  represents  the  corpuscles.1 

154.  Both  of  the  foregoing  methods  are  open  to  the  objection,  that  the  albu- 
minous and  other  constituents  of  the  Serum  are  reckoned  in  the  calculation  as 
being  equally  present  in  the  whole  water  of  the  blood.  Now  as  the  moist  Corpus- 
cles, according  to  Lehmann,  constitute  fully  half  the  mass  of  the  blood,  and  as 
they  do  not  contain  the  albuminous  elements  of  the  serum,  and  have  salines 
peculiar  to  themselves,  it  is  obvious  that  the  constituents  of  the  Serum  will  be 
estimated  far  too  high,  and  the  residue,  which  expresses  the  solid  matter  of  the 
Corpuscles,  as  much  too  low.  In  order  to  avoid  this  source  of  error,  by  separat- 
ing the  corpuscles  from  the  serum,  so  as  to  be  able  to  form  a  direct  estimate  of 
their  amount,  it  has  been  proposed  by  M.  Figuier  to  filter  the  defibrinated  blood 
after  having  added  to  it  a  solution  of  sulphate  of  soda,  the  effect  of  which  is  to 
separate  the  corpuscles  from  the  serum  without  causing  them  to  discharge  their 
contents.  This  method  has  been  adopted  by  Dumas,  Hofle,  and  Grorup-Besanez, 
and  was  employed  in  the  third  and  fourth  of  the  analyses  already  cited  (§  152); 
it  would  appear  from  these,  however,  to  produce  a  still  further  reduction  in  the 
proportion  assigned  to  the  corpuscles ;  and  for  this  it  is  not  difficult  to  account, 
when  it  is  borne  in  mind  that  the  saline  solution  will  tend  to  empty  them  of 
their  contents,  unless  its  specific  gravity  be  accurately  adjusted  (§  139).  Again, 
it  must  be  borne  in  mind  that  the  preceding  methods  of  analysis  give  no  account 
whatever  of  the  Salts  contained  in  the  Corpuscles,  which,  as  we  have  seen,  are 
very  different  from  those  of  the  Serum;  and  these  can  only  be  determined  by 
the  incineration  of  the  whole  mass  of  the  blood. — Other  methods  which  have  been 
proposed  for  the  more  precise  quantitative  determination  of  the  principal  con- 
stituents of  the  Blood,  are  not  only  tedious  and  complex,  but  involve  the  use  of 
various  reagents,  which  may  themselves  induce  considerable  changes  in  the  "  be- 
havior" -of  its  organic  components  ;2  and  in  the  present  state  of  our  knowledge, 
therefore,  it  is  impossible  to  arrive  at  any  other  than  an  approximative  estimate 
of  their  respective  amounts.  The  following  is  founded  on  the  comparative  ana- 
lyses of  the  Serum  and  Liquor  Sanguinis  already  cited  from  Prof.  Lehmann 
(§  142) ;  it  being  assumed  that  the  moist  Corpuscles  form  half  of  the  entire 
volume  of  the  blood.  This,  in  his  opinion,  is  rather  beneath  than  above  the 
actual  average,  which  he  considers  to  be  512  parts  in  1000 ;  the  limits  of  varia- 
tion in  health  being  about  40  parts  on  either  side.  By  halving  the  numbers  in 

1  It  is  a  curious  indication  of  the  uncertainty  of  the  results  of  analyses  conducted  upon 
principles  essentially  the  same,  that  whilst,  in  the  first  of  the  cases  above  cited  (§  152),  the 
proportion  of  corpuscles  given  by  Becquerel  and  Rodier's  method  was  almost  identical 
with  that  given  by  the  method  of  Scherer,  there  was  a  marked  difference  in  the  propor- 
tions of  albumen  and  extractive ;  whilst  in  the  second,  the  proportion  of  albumen  being 
almost  identical  in  the  two  analyses,  the  amounts  assigned  to  the  corpuscles  and  to  the 
extractive  respectively  differed  by  no  less  than  18  parts  in  the  1000,  for  each  of  these 
constituents. 

2  For  an  account  of  the  methods  of  Berzelius,  Denis,  and  Simon,  see  the  "Animal 
Chemistry"  of  the  last-named  author  (translated  by  Dr.  Day),  pp.  143,  et  seq.,  Am.  Ed. 


ITS   PHYSICAL,    CHEMICAL,    AND    STRUCTURAL   CHARACTERS.       173 

the  preceding  table,  therefore,  and  adding  together  those  which  refer  to  consti- 
tuents of  the  same  character,  we  obtain  the  following  results  : — 

Water  .     795.45 

Solid  residue     204.55 

Fibrin .••''.•;.'''''  .  2.025 

r        e  ioa   /  Hsematin     ....  8.375 

,orpuscles   j  Globulin  and  cell-membrane  141.110 

Albumen         "V^*  &'•<< '':.  l-:".  ; '"  ''.     ,    .  39.420 

Fatty  matters  .         .      v '.  .      .<•'.;.       .  2.015 

Extractive  matters 3.270 

Mineral  substances,  exclusive  of  iron        .  8.335 


Chlorine    . 
Sulphuric  acid 
Phosphoric  aci< 
Potassium 
Sodium     . 
Oxyge^n     . 
Phosphate  of  Lime 


2.665 

.090 

.663 

1.825 

2.197 

.535 

.212 


Phosphate  of  Magnesia     .148 

155.  Under  the  general  head  of  Fatty  Matters  are  included  several  different 
kinds  of  fat,  some  of  which  present  very  definite  characters,  whilst  the  nature  of 
others  has  not  yet  been  precisely  determined.     A  considerable  part  of  the  whole 
amount  is  formed  by  the  saponifiable  fats,  which,  in  the  human  subject,  are 
Margarin  and  Olein  (§  37)  ;  and  it  must  be  in  these  that  the  chief  increase  occurs, 
when  the  amount  of  fatty  matter  in  the  blood  is  temporarily  augmented  by  the 
entrance  of  oleaginous  chyle  (§  161).     The  proportion  of  phosphorized  fat  (§  44), 
which  seems  to  form  an  essential  constituent  of  the  Corpuscles  (§  142),  will  pro- 
bably vary  in  part  with  their  amount ;  but  the  range  of  variation  seems  to  be 
too  wide  to  admit  of  the  difference  being  fully  accounted  for  in  this  manner. 
The  presence  of  Cholesterin  (§  43)  seems  to  be  constant;  but  it,  too,  exhibits  a 
considerable  diversity  in  its  amount,  probably  depending   upon  the  relations 
between  the  biliary  secretion  and  the  respiratory  process.     Of  the  fatty  substance 
termed  Serolin  (§  43),  the  quantity  is  always  very  minute,  and  it  is  sometimes 
inappreciable. — The  following  table  represents  the  mean,  maximum,  and  mini- 
mum amounts  of  these  fatty  substances  in  the  healthy  blood  of  the  male  (the 
proportion  in  that  of  the  female  being  almost  precisely  similar),  according  to  the 
analyses  of  MM.  Becquerel  and  Rodier. 

Mean.  Max.  Min. 

Saponified  fat          .         .         .     1.004  2.000  .700 

Phosphorized  fat    .         .         .       .488  1.000  .270 

Cholesterin 088  .175  .030 

Serolin   .         .  ,.v.>  ,,-,    .         .       .020  .080  inappreciable. 

The  source  of  the  peculiar  odor  of  the  blood  is  probably  a  volatile  fatty  acid, 
too  minute  in  its  amount  to  admit  of  being  separately  estimated.  This  odor 
may  be  made  much  more  apparent  by  treating  the  blood  with  sulphuric  acid, 
even  after  it  has  been  long  dried ;  and  in  all  those  animals  which  are  readily  dis- 
tinguishable by  their  odorous  emanations,  it  may  thus  be  made  so  perceptible  as 
to  admit  of  their  blood  being  distinguished  (at  least  by  an  individual  possessed 
of  a  delicate  sense  of  smell)  through  its  scent  alone.  Of  this  test,  use  has  been 
made  with  great  advantage  in  juridical  investigations.1 

156.  Under  the  vague  term  Extractive  (§  64),  it  is  probable  that  many  dif- 
ferent substances  are  to  be  ranked;  most  of  them,  however,  being  either  histo- 

i  See  M.  Barreul's  researches  on  this  subject  in  "Ann.  d'Hygiene,"  &c.,  toms.  i.,  ii.,  x. 


174 


OF  THE   BLOOD. 


genetic  substances,  which  are  undergoing  progressive  metamorphoses,  such  as 
the  peculiar  soluble  compounds  which  are  considered  by  Mulder  as  the  binoxide 
and  tritoxide  of  protein  (§  30) ;  or  non-azotized  alimentary  matters,  or  products 
of  the  retrograde  metamorphoses  of  the  tissues,  which  are  on  their  way  to  the 
excretory  organs,  as  is  the  case  with  the  sugar,  urea,  uric  hippuric  acids,  crea- 
tine  and  creatinine,1  which  have  been  detected  in  it  in  minute  proportion.  It 
can  scarcely  be  doubted  that  the  more  attentive  study  of  this  part  of  the  blood 
will  be  attended  with  the  discovery  of  many  facts  that  would  throw  great  light 
upon  the  Chemistry  of  the  histogenetic  operations,  and  of  the  retrograde  meta- 
morphoses of  the  effete  materials  of  the  tissues. 

157.  The  list  of  the  Inorganic  Constituents  of  the  Blood,  which  is  given  in 
the  preceding  table  (§  154),  does  not  express  the  mode  in  which  they  'are 
grouped  together ;  and  it  takes  no  account  of  the  Carbonic  acid,  which  certainly 
exists  in  the  blood  united  with  Alkaline  bases  (§  83).  The  proportion  which 
the  Carbonates  bear  to  the  Phosphates,  however,  seems  to  be  small  in  Human 
blood ;  as  is  shown  by  the  following  table,  founded  on  the  analysis  of  Verdeil,2 
of  the  per-centage  c&mposition  of  the  ash  of  the  blood,  after  deducting  the  car- 
bon still  contained  in  it.  The  corresponding  analyses  of  the  blood  of  the  Dog, 
Ox,  Sheep,  and  Pig,  are  here  given,  to  show  the  remarkable  variation  between 
the  relative  amounts  of  the  Carbonates  and  Phosphates,  in  the  blood  of  Herbi- 
vorous and  Carnivorous  animals,  of  which  mention  has  already  been  made  (§  84). 
It  will  be  observed  that  the  proportion  of  Chloride  of  Sodium  exhibits  a  remark- 
able constancy. 


Man. 

Dog. 

Ox. 

Sheep. 

Pig. 

A3 

B< 

A5 

B6 

Chloride  of  Sodium 

61.99 

55.63 

49.85 

50.98 

59.12 

53.71 

57.11 

50.62 

41.31 

49.51 

Soda     .... 

2.03 

6.27 

5.78 

2.02 

13.00 

14.40 

13.33 

13.40 

7.62 

5.33 

Potassa     .     .     . 

12.70 

11.24 

15.16 

19.16 

5.60 

8.76 

5.29 

7.93 

22.21 

18.54 

Magnesia  .     .     . 

0.99 

1.26 

0.67 

4.38 

0.47 

0.59 

0.30 

0.82 

1.21 

0.97 

Sulphuric  Acid  . 

1.70 

1.64 

1.71 

1.08 

1.25 

1.16 

1.65 

1.91 

1.74 

1.34 

Phosphoric  Acid 

7.48 

9.74 

12.74 

9.34 

3.40 

3.02 

3.83 

3.41 

10.61 

11.48 

Phosphate  of  Lime 

3.55 

3.21 

1.32 

3.05 

2.51 

2.32 

2.38 

2.68 

2.88 

3.17 

Peroxide  of  Iron 

8.06 

8.68 

12.75 

8.65 

9.00 

8.80 

8.70 

9.17 

9.10 

9.52 

Carbonic  Acid    . 

1.43 

0.95 

0.53 

0.37 

6.57 

6.49 

7.09 

6.35 

0.69 

0.36 

158.  We  have  now  to  inquire  into  the  principal  modifications,  which  the 
relative  proportions  of  these  constituents  undergo  in  the  state  of  health,  under 
the  influence  of  varying  conditions  of  the  system;  and,  notwithstanding  the 
want  of  absolute  correctness  in  the  analyses  of  which  we  are  at  present  in  pos- 
session, those  that  are  made  by  similar  methods  give  results  sufficiently  trust- 
worthy to  enable  them  to  be  compared  together,  and  thus  to  give  a  tolerably 
correct  indication  of  the  circumstances  which  determine  the  increase  or  diminu- 
tion in  the  principal  components  of  the  Blood. — The  first  of  these  modifying 
conditions  which  requires  special  notice  is  Age.  During  the  latter  part  of  foatal 

1  The  discovery  of  the  presence  of  these  two  substances  in  the  blood  of  oxen  has  recently 
been  made  by  MM.  Verdeil  and  Dolfuss,  who  have  operated  upon  very  large  quantities  of 
the  fluid.     (See  M.  Board's  "Cours  de  Physiologic,"  torn.  iii.  p.  95.) 
"Ann.  der  Chem.  und  Pharm.,"  band  Ixix.  p.  89. 

3  Man,  forty-five  years  old,  suffering  from  weak  digestion. 

4  Woman,  twenty-two  years  old,  sanguineous  temperament. 
6  After  a  flesh  diet  of  eighteen  days. 

6  After  feeding  for  twenty  days  upon  bread  and  potatoes. 


ITS   PHYSICAL,    CHEMICAL,   AND    STRUCTURAL   CHARACTERS.       175 


life,  the  blood  is  remarkably  rich  in  solid  contents ;  it  being  in  the  proportion 
of  corpuscles  (including  iron)  that  the  chief  difference  exists  between  foetal  and 
maternal  blood.  This  appears  from  the  following  comparative  analyses  made 
by  Denis1  of  the  venous  blood  of  the  mother,  and  of  the  blood  of  the  umbilical 
artery,  which  last  has  been  recently  found  by  Poggiale  (as  might  be  expected) 
to  be  identical  with  the  blood  of  the  foetus. 


Water      . 

Solid  constituents 

Fibrin     . 
Corpuscles 
Albumen 
Phosphorized  Fat 
Peroxide  of  Iron 
Extractive     "--••??:' 
Salts 


Venous  Blood  of  Mother. 
.      781.0 
.     219.0 


139.9 

50.0 

9.2 

0.3 

4.2 

12.5 


Blood  of  Umbilical  Artery. 
701.5 
298.5 

2.2 

222.0 

50.0 

7.5 

2.0 

2.7 
12.1 


The  analyses  of  Poggiale2  give  255.8  parts  of  solid  matter,  of  which  172.2  parts 
were  corpuscles,  and  2  parts  of  peroxide  of  iron,  in  1000  parts  of  foetal  blood ; 
thus  agreeing  with  those  of  Denis  in  the  main  fact  of  the  excessive  proportion 
of  corpuscles  and  iron. — The  proportion  of  corpuscles  seems  to  remain  high  for 
a  short  time  after  birth ;  but  it  gradually  diminishes ;  and  the  whole  amount  of 
solid  matter  in  the  blood  seems  to  fall  to  its  lowest  point  during  the  period  of 
childhood.  Towards  the  epoch  of  puberty,  however,  the  amount  of  solid  matter 
increases  again,  the  chief  augmentation  being  in  the  corpuscles;  and  it  remains 
at  a  high  standard  during  the  most  vigorous  period  of  adult  life,  after  which  it 
begins  to  decline.  This  is  made  apparent  in  the  following  table  deduced  from 
the  analyses  of  Denis;  which  are  confirmed  by  those  of  Lecanu  and  Simon.3 


In  5  individuals  between  5  months  and  10  years 


13 

11 

12 

0 

ft 

2 


10  years  and 

20 

30 

40 

50 

60 


20 
30 
40 
50 
60 
70 


Solid  Constituents. 

170 
200 
240 
240 
240 
220 
210 


159.  An  appreciable  difference  exists  between  the  blood  of  the  two  sexes; 
that  of  the  male  being  richer  in  solid  contents,  and  especially  in  corpuscles, 
than  that  of  the  female.  On  this  point,  the  analyses  of  Lecanu,  Denis,  and 
Becquerel  and  Rodier  are  in  accordance,  notwithstanding  their  mutual  discre- 
pancies; as  the  following  tables  show: — 


BLOOD  OF  MEN. 
Water              .     . 

Becque 
Mean. 
779  0 

i-el  and  Rodier. 
Max.        Min. 
800.0     760.0 
240.0    200.0 

3.5        1.5 
152.0     131.1 
73.0       62.0 
3.2         1.0 

8.0        5.0 

Mean. 
758.0 
242.0 

2.5 
147.0 
57.5 

Denis. 
Max. 

790.0 
266.7 

2.9 
187.1 
63.0 

Min. 

733.3 
210.0 

2.1 
102.0 
52.3 

Solid  constituents 

.     221.0 
2  2 

Fibrin 

Corpuscles       .     . 
Albumen     .     .     . 
Fat              .     .     . 

.     141.1 

.       69.4 
1.6 

Extractive  and  ") 
Salts  of  Serum  / 

6.8 

Lecanu. 

Max.  Min. 

791.9    805.2  778.6 

208.1     221.4  194.8 


1  "  Recherche s  Experimentales  surle  Sanghumain,"  and  "  Simon's  Animal  Chemistry," 
p.  197,  Am.  Ed. 

2  "Comptes  Rendus,"  torn.  xxv.  p.  198.       3  "Animal  Chemistry,"  p.  198,  Am.  Ed. 


176 


OF   THE   BLOOD. 


BLOOD  OF  WOMEN. 
Water    

Becquerel  and  Rodier. 
Mean.      Max.       Min. 
791.1     813.0    773.0 

Denis. 
Mean.      Max.         Min. 

773.0    820.0    750.0 

Lecanu. 
Mean.      Max.        Min. 

821.7     853.1     790.3 

Solid  constituents     . 

208.9    227.0    187.0 

227.0    250.0     180.0 

178.3     146.9    209.7 

Fibrin 

2.2        2.5         1.8 

2.7        3.0        2.5 

Corpuscles       .     .     . 
Albumen    .... 
Fat   

127.2     137.5     113.0 
70.5      75.5      65.0 
1.6        2.9        5.0 

138.0     162.4      88.1 
61.2      66.4      50.0 

Extractive  and  \ 
Salts  of  Serum  /      ' 

7.4        8.5        6.2 

From  these  it  would  appear  that  the  mean  excess  of  the  whole  solid  constituents 
in  the  blood  of  the  male  above  those  of  the  female,  is  reckoned  by  the  several 
experimenters  at  from  12  to  20  parts  in  1000;  and  that  the  variation  is  the 
greatest  in  the  proportion  of  corpuscles,  neither  of  the  other  elements  exhibiting 
any  considerable  difference  in  their  amount  in  the  two  sexes.  The  excess  in 
the  solid  constituents  of  the  male  blood  above  those  of  the  female  is  as  well 
marked  in  the  extreme  as  in  the  mean  results ;  for  the  maxima  in  the  female 
do  not  pass  much  higher  than  the  mean  of  the  male,  whilst  her  minima  fall  far 
below  his;  on  the  other  hand,  the  maxima  of  the  male  rise  far  higher  than  those 
of  the  female,  whilst  his  minima  scarcely  descend  below  her  mean. 

160.  It  is  obvious,  from  the  extent  of  diversity  shown  in  the  preceding  table, 
that  the  proportions  of  the  constituents  must  vary  considerably  with  individual 
temperament  and  constitution.     All  the  persons  whose  blood  furnished  the  sub- 
jects of  the  preceding  analyses  were  (or  considered  themselves  to  be)  in  perfect 
health ;  but  their  standard  of  health  could  not  have  been  by  any  means  uniform. 
There  is  no  doubt  that,  in  individuals  of  the  plethoric  or  "  sanguineous"  tem- 
perament, the  proportion  of  the  whole  solid  constituents,  and  especially  of  the 
corpuscles,  is  considerably  greater  than  in  persons  of  the  "  lymphatic"  tempera- 
ment; and  it  appears,  from  the  analyses  of  Lecanu,1  that  the  sexual  difference  in 
the  blood  almost  disappears  when  the  blood  of  males  and  of  females  of  the  latter 
temperament  is  compared. 

161.  A  considerable  influence  is  exercised  on  the  entire  amount,  and  on  the 
relative  proportions,  of  the  constituents  of  the  Blood,  by  the  previous  ingestion 
of  food  or  drink,  and  by  the  diet  habitually  employed.     The  observations 
hitherto  made  upon  the  first  of  these  points,  however,  are  not   sufficiently 
numerous  to  admit  of  being  generalized;  and  the  chief  points  that  can  be  defi- 
nitely stated  are  those  which  have  been  substantiated  by  Profs.  Buchanan  and 
R.  I).  Thompson,2  in  their  examination  of  blood  whose  serum  exhibits  the 
"milky"  appearance,  which,  when  it  occurs  in  health,  is  due  to  the  entrance  of 
chyle,  more  rapidly  than  its  oleaginous  matter  can  be  eliminated  by  the  respi- 
ration or  appropriated  by  the  tissues.     When  a  full  meal  containing  oily  matter 
is  taken  after  a  long  fast,  and  a  small  quantity  of  blood  is  drawn  previously  to 
the  meals  and  at  intervals  subsequently,  the  serum,  though  quite  limpid  in  the 
blood  first  drawn,  shows  an  incipient  turbidity  about  half  an  hour  afterwards ; 
this  turbidity  increases  for  about  six  hours  subsequently,  after  which  it  usually 
begins  to  disappear.     The  period  at  which  the  discoloration  is  the  greatest, 
however,  and  the  length  of  time  during  which  it  continues,  vary  according  to 
the  kind  and   quality  of  the  food,  and  the  state  of  the  digestive  functions. 
Neither  starch  nor  sugar,  nor  proteine  compounds,  alone  or  combined,  occasion 
this  opacity  in  the  chyle ;  but  it  seems  essentially  dependent  upon  an  admixture 


1  "Etudes  Chimiques  sur  le  Sang  humain,"  p.  66 ;  and 
196,  Am.  Ed. 

2  "Medical  Gazette,"  Oct.  10,  1845. 


Simon's  Animal  Chemistry," 


ITS   PHYSICAL,    CHEMICAL,    AND    STRUCTURAL   CHARACTERS.      177 

of  oleaginous  matter  with  the  food.     There  are  few  ordinary  meals,  however, 
from  which  such  matter  is  altogether  excluded.     When  such  milky  serum  is 
examined  with  the  Microscope,  the  opacity  is  found  to  be  due  to  the  presence 
of  an  immense  number  of  exceedingly  minute  granules,  resembling  in  appearance 
those  which  form  the  "  molecular  base"  of  the  chyle.     They  seem  to  be  com- 
posed of  two  chemically  distinct  substances;  for  when  the  milky  serum  is  agi- 
tated with  ether,  a  part  is  dissolved,  whilst  another  portion  remains  suspended; 
and  this  latter  is  soluble  in  caustic  potass.     The  former,  therefore,  appears  to 
be  identical  with  the  "molecular  base"  of  the  Chyle,  and  to  be  of  an  oily  or  fatty 
nature;  whilst  the   latter  belongs  to  the  proteine  compounds.     The  Crassa- 
mentum  of  such  blood  often  exhibits  a  pellucid  fibrinous  crust,  sometimes  inter- 
spersed with  white  dots ;  and  this  seems  to  consist  of  an  imperfectly-assimilated 
proteine  compound,  analogous  to  that  found  in  the  serum.     The  quantity  of  this 
varies  according  to  the  amount  of  the  proteine  compounds  present  in  the  food. — 
The  presence  of  saccharine  matter  in  the  blood  (in  which  it  forms  part  of  the 
"  extractive"),  after  the  ingestion  of  a  large  quantity  of  saccharine  or  farina- 
ceous aliment,  has  been  noticed  by  many  experimenters. — It  might  be  fairly 
presumed  that  a  temporary  augmentation  must  take  place  in  the  aqueous  con- 
stituent of  the  blood,  whenever  any  considerable  quantity  of  liquid  is  ingested ; 
and  yet  this  augmentation  is  probably  much  less  considerable,  under  ordinary 
circumstances,  than  we  should  at  first  be  inclined  to  suppose.     For  there  exist 
various  provisions  in  the  system  (the  peculiar  Malpighian  apparatus  of  the 
kidneys  being  the  chief)  for  rapidly  freeing  the  blood  from  any  superfluity  of 
water ;  and  thus  any  excess  of  fluid  absorbed  is  speedily  drawn  off  again.     But 
further,  there  is  evidence  that,  when  the  vessels  are  already  filled,  absorption 
does  not  take  place  with  nearly  the  same  readiness  as  after  long  abstinence  from 
liquids ;  the  rate  of  absorption  being  in  great  degree  governed  by  that  at  which 
the  liquid  is  disposed  of.     It  follows,  therefore,  that  the  absorption  of  even  a 
considerable  amount  of  water  within  a  short  time,  need  not  really  involve  any 
great  dilution  of  the  blood ;   and  it  is  probable  that  a  considerable  previous 
reduction  of  its  density  will  only  take  place  in  a  state  of  health,  when  it  has 
first  undergone  an  unusual  elevation,  in  consequence  of  the  removal  of  part  of 
its  water  by  perspiration,  diuresis,  &c.,  without  a  corresponding  replacement  of 
it  by  absorption.     It  has  been  affirmed,  however,  that  when  Oxen  have  taken 
immense  draughts  of  water,  the  blood  has  been  so  much  diluted,  that  some  of 
the  corpuscles  have  burst  (§  139)  and  the  coloring  matter  has  passed  out  of  the 
body;  whilst,  on  the  other  hand,  it  has  been  found  that  when  two  dogs  had 
been  kept  for  some  weeks  on  the  same  kind  of  food,  but  one  was  not  allowed  to 
drink,  whilst  the  other  was  made  to  take  a  large  quantity  of  water,  the  specific 
gravity  of  the  blood  was  nearly  the  same  in  each.1 — The  influence  of  the  regimen 
upon  the  composition  of  the  blood,  however,  appears  to  be  more  definite  and 
constant.     An  animal  diet  tends  to  increase  the  whole  amount  of  solid  matter, 
but  especially  to  augment  the  proportion  of  corpuscles.     On  the  other  hand,  a 
vegetable  diet  tends  to  lower  the  whole  amount  of  solid  matter,  occasioning  a 
marked  reduction  in  the  corpuscles,  whilst  it  seems  rather  to  increase  the  albu- 
men ;  thus  showing  that  the  decrease  in  the  corpuscles  is  not  due  to  a  deficiency 
in  their  azotized  pabulum,  but  depends  on  some  other  condition.     The  develop- 
ment of  fibrin  appears  to  take  place  at  least  as  readily  on  the  vegetable  as  on 
the  animal  regimen.     Hence  we  see  what  may,  and  what  may  not,  be  effected 
in  the  treatment  of  disease,  by  the  adoption  of  a  particular  dietetic  system,  for 
we  may  promote  or  retard  the  development  of  the  red  corpuscles,  by  the  employ- 
ment of  an  animal  or  a  vegetable  regimen,  but  can  make  little  or  no  impression 

1  Dr.  Bence  Jones,  in  "Medical  Times,"  Aug.  2,  1851,  p.  115. 
12 


178  OF   THE   BLOOD. 

upon  the  fibrin.1 — The  effect  of  complete  abstinence  from  food,  also,  or  of  a  con- 
tinued insufficient  supply  of  it,  is  to  reduce  the  proportion  of  the  whole  solid 
constituents ;  but  in  this  case,  too,  the  corpuscles  are  much  more  reduced  than 
the  albumen ;  and  very  little  effect  is  produced  upon  the  fibrin,  which  at  once 
undergoes  an  absolute  increase,  if  any  inflammatory  affection  should  develop 
itself. 

162.  The  effect  of  Loss  of  blood  is  of  a  very  similar  nature  to  that  of  absti- 
nence. Almost  as  soon  as  the  stream  begins  to  flow  from  a  wounded  vessel, 
there  seems  to  be  a  transudation  of  watery  fluid  from  the  tissues  into  the  current 
of  blood  j  for  this  undergoes  a  rapid  diminution  in '  density,  so  that  the  portion 
last  drawn  is  of  lower  specific  gravity,  and  contains  a  considerably  smaller 
amount  of  solid  matter,  than  that  which  first  issued.  This  fact,  which  has  long 
been  known,  has  of  late  been  more  precisely  determined  by  Drs.  Zimmerman,3 
Polli,3  and  J.  Davy.4  When  blood  has  been  repeatedly  drawn,  or  has  been  lost 
by  hemorrhage,  that  which  remains  is  impoverished ;  but  the  reduction  in  its 
whole  amount  of  solid  matter  here  too  lies  rather  in  the  diminution  of  the  cor- 
puscles, than  in  that  of  the  other  constituents.  This  is  shown  by  the  following 
table  of  the  results  of  MM.  Becquerel  and  Rodier's  analyses  of  the  blood  of 
ten  patients,  each  of  whom  had  been  bled  three  times  : — 

1st  Venesection.    2d  Venesection.    3d  Venesection. 

Specific  gravity  of  defibrinated  blood        1056.0  1053.0  1049.6 

serum  1028.8  1026.3  1025.6 


Water   . 

Solid  Residue 

Fibrin    . 

Corpuscles     . 

Albumen 

Extractive  and  saline  matters 

Fat 


793.0  807.7  833.1 

207.0  192.3  176.9 

3.5  3.8  3.4 
129.2  116.3  99.2 

65.0  63.7  64.6 

7.7  6.9  8.0 

1.6  1.6  1.5 


Hence  it  is  obvious  that  the  special  effect  of  bleeding  is  to  lower  the  proportion 
of  red  corpuscles,  and  that  it  has  no  power  of  effecting  a  diminution  in  the 
amount  of  fibrin.  We  shall  find,  indeed,  that  in  inflammatory  diseases  the 
amount  of  fibrin  undergoes  an  extraordinary  increase  (§  176),  which  is  not 
checked  in  the  slightest  appreciable  degree  by  the  most  copious  venesection. 

163.  'We  have  now  to  consider  the  differences  which  present  themselves  in  the 
composition  of  the  blood  drawn  from  different  vessels  of  the  same  body;  these, 
it  is  obvious,  being  dependent  on  the  changes  to  which  the  fluid  is  subjected, 
during  its  passage  through  organs  that  will  appropriate  or  change  its  several 
constituents  in  an  unequal  degree.  And  the  first  and  most  important  of  these 
sets  of  differences  is  that  which  exists  between  Arterial  and  Venous  blood. 
The  analyses  already  cited  having  been  made  chiefly  upon  the  latter,  it  will  be 
sufficient  here  to  state  the  general  results  of  comparative  inquiries  into  the  com- 
position of  the  former.  The  quantity  of  solid  constituents  pertaining  to  the 
Corpuscles  is  smaller ;  they  contain  relatively  more  hsematin  and  salts,  but  much 
less  fat.  The  liquor  sanguinis  is  somewhat  richer  in  Fibrin;  but  it  contains  a 
larger  proportion  of  water,  and  consequently  less  Albumen.  The  Fatty  mat- 
ters of  the  serum,  as  well  as  of  the  corpuscles,  are  considerably  diminished ;  on 
the  other  hand,  the  Extractive  matters  are  decidedly  increased.  It  is  affirmed 
by  Dr.  G-.  0.  Rees,5  that  the  phosphorus  which  exists  in  venous  blood  in  an 

1  See  on  this  subject  the  treatise  of  M.  Emile  Marchand,  "De  1'Influence  comparative 
du  Regime  Vegetal  et  du  Regime  Animal  sur  le  Physique  et  le  Moral  de  1'Homme." 

2  "Heller's  Archiv,"  band  iv.  p.  385. 

3  See  "  Medico-Chirurgical  Review,"  Oct.  1847. 


4  "Anatomical  and  Physiological  Researches,"  vol.  ii.  p.  28. 
6  "Philosophical  Magazine,"  vol.  xxxiii.  p.  28. 


ITS   PHYSICAL,    CHEMICAL,    AND    STRUCTURAL   CHARACTERS.       179 

unoxidized  state,  united  with  the  fat  of  the  corpuscles,  is  converted  by  the  respi- 
ratory process  into  phosphoric  acid,  which  passes  into  the  serum  and  unites  with 
alkaline  bases;  and  this  view  seems  borne  out  by  the  more  recent  analyses  of 
Reich.1  The  most  remarkable  difference  between  Arterial  and  Venous  blood, 
however,  lies  in  the  amount  of  free  gases  which  they  respectively  contain.  It 
may  now  be  considered  as  unquestionably  proved  by  the  researches  of  Stevens, 
Bischoff,  J.  Davy,  Magnus,  and  others  (but  more  especially  by  those  of  the  last- 
named  experimenter),  that  both  venous  and  arterial  blood  contain  Oxygen,  Nitro- 
gen, and  Carbonic  acid  in  a  state  of  solution ;  these  gases  being  yielded  up  by 
the  blood  when  it  is  placed  in  a  perfect  vacuum;3  and  carbonic  acid  being  also 
disengaged  when  the  fluid  is  shaken  with  common  air  or  with  oxygen,  hydrogen, 
or  nitrogen ;  whilst  oxygen  is  in  like  manner  expelled  by  hydrogen  or  nitrogen, 
which  takes  its  place.  The  experiments  of  Magnus3  show  that  from  10  to  12 1 
per  cent,  of  Oxygen  (by  volume)  exists  in  arterial  blood ;  but  that  this  is  re- 
duced in  venous  blood  to  half  its  amount.  On  the  other  hand,  the  quantity  of 
Carbonic  acid  which  is  thus  removable  amounts  to  about  25  per  cent,  (by  volume) 
in  venous  blood,  and  to  only  20  in  arterial.  The  per-centage  of  Nitrogen  was 
found  to  vary  from  1.7  to  3.3;  but  no  constant  difference  presented  itself  be- 
tween the  quantities  contained  in  arterial  and  in  venous  blood  respectively. .  The 
differences  in  the  relative  proportions  of  Oxygen  and  Carbonic  acid  in  arterial 
and  venous  blood  respectively,'  confirm  the  indications  afforded  by  other  facts 
(CHAP,  x.),  that  an  exchange  of  oxygen  for  carbonic  acid  takes  place  in  the 
systemic  circulation,  and  an  exchange  of  carbonic  acid  for  oxygen  in  the  general 
circulation.  How  far  the  gases  thus  introduced  into  the  blood  enter  into  chemi- 
cal combination  with  any  of  its  constituents,  or  are  merely  dissolved  in  the  liquid, 
has  not  been  positively  determined;  there  is  reason  to  think,  however,  that  if 
combination  thus  takes  place,  the  proportion  so  employed  is  extremely  small.4 
The  remarkable  power  of  absorbing  carbonic  acid,  which  is  possessed  by  the 
Serum,  and  still  more  by  the  Red  Corpuscles,  has  been  already  mentioned 
(§§  84,  142);  and  there  would  be  no  difficulty  in  accounting  for  the  presence 
of  many  times  the  amount  of  that  gas  which  is  actually  found  in  the  blood, 
without  supposing  it  to  lose  its  freedom  by  combination. 

164.  The  increase  of  the  Fibrin,  however,  which  seems  to  be  effected  during 
the  aeration  of  the  Blood,  must  be  taken  as  an  indication  that  a  certain  part  of 
the  oxygen  absorbed  from  the  air  is  made  directly  subservient  to  changes  in  the 
composition  of  the  circulating  fluid;  and  from  what  has  been  already  stated 
(§  25),  it  appears  that  the  fibrin  of  arterial  blood  is  in  a  state  of  higher  oxida- 
tion than  that  of  venous.  Now  although,  for  the  reasons  formerly  given 
(§§  25-29),  we  must  regard  the  conversion  of  albumen  into  fibrin  as  rather  a 
vital  than  a  chemical  change,  yet  the  existence  of  the  difference  in  question 
obviously  points  to  the  presence  of  oxygen  as  a  condition  essential  to  its  per- 
formance; and  this  inference  is  fully  confirmed  by  the  recent  experiments  of 
Dr.  Grairdner,5  on  the  influence  of  the  respiration  of  pure  oxygen  on  the  pro- 
duction of  fibrin.  As  the  Rabbit  was  on  many  accounts  the  most  convenient 
warm-blooded  animal  for  such  a  trial,  he  first  set  himself  to  determine  the  nor- 

1  "Archiv.  der  Pharmacie,"  and  "Liebig  and  Kopp's  Report,"  for  1849,  p.  366. 

2  It  has  been  found  by  Magnus,  that  carbonic  acid  is  not  given  off  under  the  receiver  of 
an  air-pump,  until  the  air  has  been  so  far  exhausted  that  it  only  supports  one  inch  of  mer- 
cury.    This  fact  explains  the  negative  result  obtained  by  many  experimenters ;  since  an 
extremely  good  air-pump  is  required  to  produce  such  a  degree  of  exhaustion. 

3  See  "Ann.  der  Physik  und  Chemie,"  band  Ixvi.  p.  177 ;  and  an  abstract  in  the  "Philo- 
sophical Magazine,"  Dec.  1845. 

4  See  Lehmann,  Op.  cit.,  Bd.-  ii.  p.  181. 

5  Treatise  "On  Gout,"  2d  edit.,  pp.  153,4. 


180  OF   THE   BLOOD. 

mal  proportions  of  the  constituents  of  its  blood.  The  analyses  of  the  blood 
drawn  from  the  aorta  in  six  healthy  individuals  yielded  the  following  results  : — 

Mean.  Max.  Min. 

Fibrin  .     -'^:  '-;;:     '.         .         .         1.65  2.00  1.45 

Corpuscles 82.35  92.00  70.00 

Albumen       .:,,:    ;i.  »•'/.:,:   r.       46.30  58.00  37.20 

On  the  other  hand,  the  analyses  of  the  blood  of  three  individuals  which  had 
been  made  to  respire  pure  oxygen  for  half  an  hour,  gave  the  following  as  the 
proportions  of  its  components  : — 

Mean.  Max.  Min. 

Fibrin 2.40  2.50  2.30 

Corpuscles 69.56  75.00  60.50 

Albumen 40.23  45.70  35.00 

It  is  further  stated  by  Dr.  G-airdner  (Op.  cit.,  p.  183),  that  a  rabbit  having 
been  kept  for  half  an  hour  under  the  influence  of  an  electro-magnetic  current 
between  the  chest  and  spine,  which  produced  a  great  acceleration  in  the  respi- 
ratory movements,  its  blood  was  found  to  contain  as  much  as  2.9  parts  of  fibrin 
in  10"00.  The  larger  quantity  of  fibrin  in  arterial  blood  of  itself  renders  its 
coagulum  firmer;  but  independently  of  this,  there  would  seem  to  be  a  difference 
in  the  quality  of  the  fibrin,  which,  when  separated  by  stirring  or  whipping,  is 
more  tenacious  and  compact  in  arterial  than  in  venous  blood. 

165.  The  proportion  of  Red  Corpuscles  in  arterial  and  venous  blood  respect- 
ively, has  been  variously  stated  by  different  observers;  and  we  may  easily  con- 
ceive it  to  be  affected  by  several  circumstances,  which  may  produce  a  change  in 
the  whole  proportion  of  the  solid  to  the  fluid  constituents  of  the  blood,  during 
the  course  of  its  circulation.  Thus,  the  discharge  of  the  contents  of  the  thora- 
cic duct  into  the  venous  system  near  the  heart,  will  tend  to  dilute  the  blood  of 
the  pulmonary  and  arterial  circulation;  whilst,  conversely,  the  escape  of  the 
watery  part  of  the  blood  by  the  renal  and  cutaneous  secretions,  and  by  trans- 
udation  into  the  tissues,  which  takes  place  during  its  passage  through  the  sys- 
temic capillaries,  will  tend  to  augment  the  proportion  of  the  solids  of  the  blood 
drawn  from  the  systemic  veins.  On  the  other  hand,  if  the  discharge  of  fluid 
from  the  thoracic  duct  be  suspended,  and  the  amount  absorbed  from  the  tissues 
during  the  systemic  circulation  should  exceed  that  which  is  transuded  (as  ap- 
pears sometimes  to  happen,  §  162),  then  the  proportion  of  solid  matter  will  be 
'  less  in  venous  than  in  arterial  blood.  No  such  explanation  will  apply,  however, 
to  the  very  marked  differences  exhibited  in  Dr.  Gairdner's  experiments  just 
cited,  between  the  proportions  of  red  corpuscles  and  of  albumen  in  the  ordinary 
arterial  blood  of  rabbits,  and  in  that  of  the  individuals  whose  blood  had  been 
hyper-arterialized;  the  sum  of  the  averages  in  the  former  case  being  128.65, 
and  in  the  latter  109.79,  the  difference  of  which  is  18.86,  or  nearly  one-seventh 
of  the  larger  amount.  Still,  that  this  difference  is  in  great  part  due,  rather  to 
dilution  of  the  blood  than  to  the  absolute  diminution  in  its  entire  amount  of 
red  corpuscles  and  of  albumen,  would  seem  probable  from  the  fact  that  their 
relative  amount  is  almost  exactly  the  same  in  the  two  cases,  the  proportion  of 
corpuscles  to  albumen  being  1.78  :  1  in  the  normal  blood,  and  1.72  :  1  in  the 
oxygenated.1 

166.  The  difference  in  the  hues  of  arterial  and  of  venous  blood,  which  is 
entirely  dependent  upon  the  state  of  the  Red  Corpuscles,  has  been  supposed  to 
be  produced  by  a  chemical  change  exerted  upon  their  Haematin  (§  31)  by  oxygen 

1  It  would  be  important  to  determine  the  comparative  amount  of  carbonic  acid,  and  of 
the  solids  of  the  urine,  excreted  in  the  same  time  by  two  sets  of  animals  placed  under 
these  very  diverse  conditions. 


ITS   PHYSICAL,    CHEMICAL,    AND   STRUCTURAL   CHARACTERS.      181 

and  carbonic  acid  respectively.  Of  such  change,  however,  there  is  no  adequate 
evidence;  and  there  are  many  indications  that  we  are  to  look  for  the  source  of 
the  difference  of  color,  rather  in  modifications  in  the  form  of  the  corpuscles, 
affecting  their  power  of  transmitting  and  reflecting  light,  than  in  any  chemical 
alterations  of  their  contents.  It  is  true  that  if  arterial  blood  be  exposed  to  car- 
bonic acid  out  of  the  body,  it  will  acquire  the  dark  hue  of  venous  blood ;  whilst, 
conversely,  venous  blood  exposed  to  oxygen  will  acquire  (on  its  surface  at  least) 
the  florid  hue  of  arterial  blood.  But  for  these  changes  to  take  place,  it  is  neces- 
sary that  the  normal  proportion  of  saline  matter  should  exist  in  the  serum  in 
which  the  corpuscles  float,  and  that  the  corpuscles  themselves  should  not  have 
ruptured  and  discharged  their  hgematin.  For  if  arterial  blood  deprived  of  its 
fibrin  be  diluted  with  twice  or  thrice  its  volume  of  water,  it  assumes  a  dark  venous 
tint,  which  is  not  affected  by  the  passage  of  a  current  of  oxygen  through  it ;  yet 
the  red  color  is  restored  by  the  addition  of  a  saturated  solution  of  a  neutral  salt, 
even  without  the  contact  of  oxygen.  On  the  other  hand,  venous  blood  is  red- 
dened by  the  addition  of  a  strong  saline  solution,  without  any  exposure  to  oxygen ; 
and  it  is  not  readily  darkened  again  by  the  passage  of  carbonic  acid  through  it. 
Again,  a  scarlet  clot  is  darkened  by  washing  it  with  distilled  water,  and  is  only 
very  slowly  reddened  by  exposure  to  oxygen ;  whilst  a  black  clot  becomes  at  once 
scarlet  when  it  is  washed  with  salt,  and  is  not  blackened  again  by  carbonic  acid. 
Further,  if  the  corpuscles  be  treated  with  water  until  they  burst,  so  that  the 
hsematin  is  diffused  through  the  liquid,  scarcely  any  effect  is  produced  upon  the 
hue  of  the  solution,  either  by  carbonic  acid,  by  oxygen,  or  by  salines ;  such  slight 
alteration  as  does  occur  being  fairly  attributable,  either  to  the  presence  of  a  few 
corpuscles  still  unruptured,  or  to  the  influence  which  the  absorption  of  these 
gases  may  produce  upon  the  coloring  matter,  without  entering  into  chemical 
combination  with  it.1 — Hence  it  is  obvious  that  the  light  or  dark  color  of  the 
blood  affords  no  indication  whatever  of  its  state  of  oxygenation,  since  the  change 
from  the  one  to  the  other  may  be  effected  by  other  agents;  and  if  we  examine 
into  the  nature  of  their  influence,  we  find  that  the  blood  is  darkened  by  whatever 
tends  to  distend  the  corpuscles,  so  as  to  render  them  flat  or  bi-convex,  whilst  it 
is  brightened  by  whatever  tends  to  empty  them,  so  as  to  render  them  more  deeply 
bi-concave  than  usual.  And  observation  of  the  effects  of  oxygen  and  carbonic 
acid,  respectively,  upon  the  form  of  the  corpuscles,  confirms  the  idea  that  this  is 
the  mode  in  which  these  agents  affect  their  color ;  for  the  former  causes  their 
contraction,  and  renders  their  cell-walls  thick  and  granular,  so  as  to  increase  their 
power  of  reflecting  light ;  whilst  the  latter,  producing  a  dilatation  of  the  corpus- 
cles, thins  their  cell-walls,  and  enables  them  to  transmit  light  more  readily. 
That  an  increase  in  the  opacity  and  reflecting  power  of  the  corpuscles  tends  to 
heighten  the  color  of  the  blood,  is  shown  by  an  experimenter  of  Scherer's;  who 
found  that,  when  defibrinated  blood  had  been  darkened  by  the  addition  of  water, 
its  original  bright  color  was  restored  by  the  addition  of  a  little  milk,  oil,  or  finely 
powdered  chalk  or  gypsum.3 

167.  No  difference  can  be  detected  between  samples  of  blood  drawn  from 
various  parts  of  the  arterial  system  of  the  same  animal;  but  very  important 
variations  exist,  as  might  be  expected,  in  the  composition  of  the  blood  drawn  from 
the  several  parts  of  the  venous  system,  since  the  changes  to  which  it  has  been 
subjected  in  the  several  organs  through  which  it  has  passed  are  of  a  very  diversi- 
fied character.  The  blood  of  the  vena  portae,  for  example,  differs  considerably 

1  It  has  been  shown  by  Peligot,  that  the  colors  of  solutions  of  the  salts  of  the  protoxide 
of  iron  are  considerably  modified  by  passing  a  current  of  protoxide  of  nitrogen  through 
them,  although  no  chemical  change  is  thereby  induced. 

2  See,  on  this  subject,  the  Reports  by  Scherer  in  "Canstatt's  Jahresbericht"  for  1844 
and  subsequent  years,  and  the  works  therein  referred  to;  also  Mulder's  "Chemistry  of 
Animal  and  Vegetable  Physiology"  (translated  by  Prof.  Johnston),  pp.  338-344. 


182  OF   THE   BLOOD. 

from  the  blood  of  the  hepatic  vein,  and  both  of  these  differ  from  the  blood  of  the 
jugular.  So,  again,  the  blood  of  the  splenic  vein  differs  from  all  the  preceding ; 
and  so  must  the  blood  of  the  renal  vein,  although  this  latter  difference  has  not 
yet  been  demonstrated  by  direct  analysis.  The  most  important  and  best  esta- 
blished of  these  diversities  will  now  be  enumerated. — In  speaking  of  the  compo- 
sition of  the  blood  of  the  Vena  Portse,  it  must  be  remembered  that  this  consists 
of  two  very  distinct  factors,  namely,  the  blood  of  the  gastric  and  mesenteric  veins, 
and  the  blood  of  the  splenic  vein;  the  former  having  been  altered  by  the  intro- 
duction of  solid  and  liquid  alimentary  matters,  and  the  latter  by  its  circulation 
through  the  spleen.  These,  therefore,  ought  to  be  separately  studied  ;  and  this 
has  been  done  by  M.  Jules  Be'clard.1  The  characters  of  the  blood  returning  by 
the  Gastric  and  Mesenteric  veins  from  the  walls  of  the  alimentary  canal,  are' of 
course  affected  by  the  stage  of  the  digestive  process,  and  by  the  nature  and  amount 
of  the  absorbable  matters.  As  compared  with  the  ordinary  venous  blood,  the 
total  quantity  of  its  solid  constituents  is  lowered  during  the  early  part  of  the 
digestive  process,  by  the  dilution  it  suffers  through  the  imbibition  of  liquid;  and 
this  diminution  is  especially  remarkable  in  the  corpuscles,  the  relative  proportion 
of  albumen  being  increased  by  the  introduction  of  new  albuminous  matter  from 
the  food.  Towards  the  conclusion  of  the  digestive  process,  however,  the  blood 
of  the  mesenteric  veins  gradually  comes  to  present  the  ordinary  proportions  of 
these  two  components;  and  in  an  animal  that  has  been  subjected  to  long  absti- 
nence, it  does  not  differ  from  that  of  the  venous  system  in  general.  The  quan- 
tity of  extractive  is  usually  increased ;  and  in  this  part  of  the  blood  it  must  be, 
that  sugar,  dextrin,  gelatin,  and  other  soluble  organic  matters  that  are  taken 
into  the  circulation,  are  contained.  Some  of  these  have  in  fact  been  detected 
in  it.3  The  fibrin  of  the  blood  of  the  mesenteric  veins  appears  to  be  less  per- 
fectly elaborated  than  that  of  the  blood  in  general ;  for  the  blood  of  the  mesen- 
teric veins  coagulates  less  perfectly  (having  been  erroneously  asserted  by  some 
not  to  coagulate  at  all) ;  and  its  fibrin,  when  separated  by  stirring,  shows  a 
marked  deficiency  in  tenacity,  and  liquefies  completely  in  the  course  of  a  few 
hours.  A  part  of  the  albuminous  constituent  of  the  blood  does  not  present  the 
characters  of  true  albumen,  for  it  is  not  precipitated  by  heat  or  by  nitric  acid, 
and  the  precipitate  thrown  down  by  alcohol  is  redissolved  by  water;  like  albu- 
men, however,  it  is  precipitated  by  the  metallic  salts,  creasote,  and  tannin. 
This  substance,  which  has  been  distinguished  by  M.  Mialhe  as  alluminose, 
further  differs  from  true  albumen  in  the  facility  with  which  it  traverses  organic 
membranes;  for  these  resist  the  passage  of  albumen,  while  they  are  freely 
transuded  by  albuminose.  And  it  is  affirmed  by  M.  Mialhe,  that  the  want  of 
that  conversion  of  albuminose  into  albumen,  which  ought  to  take  place  as  part 
of  the  assimilating  process,  is  one  cause  of  the  readiness  with  which  albumin- 
ous matter  transudes  from  the  blood  in  albuminuria  and  in  dropsies;  this  albu- 
minous matter  frequently  having  rather  the  characters  of  albuminose  than 
those  of  true  albumen.3 

168.  On  the  other  hand,  the  blood  of  the  Splenic  vein  exhibits  a  notable 
diminution  in  the  proportion  of  red  corpuscles,  whilst  its  albumen  is  greatly 
augmented,  the  total  amount  of  its  solid  matter  differing  but  little  from  that  of 
arterial  blood;  as  is  shown  by  the  following  comparative  statement  of  the  pro- 
portions of  the  water  and  the  solids-  of  the  blood  of  the  same  animal  in  different 
parts  of  its  circulation. 

1  See  his  Memoir  in  the  "Arch.  Gen.  de  Med.,"  4e  serie,  torn,  xviii.,  p.  322,  et  seq. ; 
and  his  edition  of  his  father's  "Elements  d' Anatomic  Generale, "  pp.  265,  2\H>. 

2  See  the  Researches  of  MM.  Bouchardat  and  Sandras,  in  the  "Supplement  al'Annuaire 
de  Therapeutique,"  1846. 

3  See  the  "Cours  de  Physiologic"  of  M.  Paul  Berard,  torn.  iii.  p.  87. 


ITS   PHYSICAL,    CHEMICAL,    AND    STRUCTURAL   CHARACTERS.      183 

External  Mammary  Splenic 

Jugular  Vein.  Artery.  Vein. 

Water 778.9  750.6  746.3 

Albumen 79.4  89.5  124.4 

Corpuscles  and  Fibrin      .  l;,r     .     141.7  159.9  128.9 

A  part  of  this  augmented  albumen  exists  in  the  form  of  neutral  albuminate  of 
soda  (§  20)  ;  so  that  the  serum  of  the  splenic  blood  (as  shown  by  Scherer)  be- 
comes turbid  on  the  addition  of  water.  The  proportion  of  fibrin  seems  to  be 
larger  in  the  blood  of  the  splenic  vein  than  in  that  of  the  venous  system  in 
general ;  but,  like  that  of  the  mesenteric  vein,  the  separated  fibrin  is  deficient 
in  tenacity,  and  early  passes  into  the  state  of  liquefaction.  The  serum  of  the 
blood  of  the  splenic  vein  of  the  horse  was  found  by  M.  Beclard  in  two  instances  to 
undergo  spontaneous  coagulation,  five  and  eight  hours  after  its  removal  from  the 
crassamentum,  in  contact  with  which  it  had  been  left  for  the  preceding  twenty- 
four  hours.  This  spontaneous  coagulation  indicates  the  existence  of  a  compound 
of  a  fibrinous  nature,  which,  however,  could  not  have  been  fully  elaborated, 
since  it  did  not  coagulate  with  the  true  fibrin,  and  which  differed  from  albumen 
in  the  spontaneity  of  its  change  of  state;  and  we  may  consider  the  substance, 
with  much  probability,  to  have  been  in  a  transition-state  between  the  two.  The 
peculiar  cells  containing  red  corpuscles,  which  form  part  of  the  parenchyma  of 
the  Spleen  (CHAP.  vni.  SECT.  3),  are  not  unfrequently  to  be  observed  in  the 
blood  of  the  splenic  vein;  being  very  abundant,  according  to  Ecker,  in  that  of 
the  horse. 

169.  Many  comparative  observations  have  been  made  upon  the  blood  of  the 
venaportaz  and  of  the  hepatic  vein;  but  a  large  part  of  them,  according  to  M. 
Cl.  Bernard,  are  vitiated  by  the  fact,  that,  unless  the  vena  portae  be  tied,  a  re- 
flux of  blood  takes  place  into  it  from  the  liver,  so  that  the  blood  which  flows 
when  it  is  wounded  is  not  so  much  portal  as  hepatic  blood.  According  to  this 
experimenter,  the  blood  of  the  hepatic  vein  is  peculiar  as  containing  an  increased 
proportion  of  sugar  and  fat,  which  are  generated  from  its  other  components 
during  its  passage  through  the  liver  (§§  40,  45—47) ;  and  he  also  maintains 
that  there  is  a  decided  augmentation  in  the  quantity  of  fibrin  which  it  contains.1 
At  any  rate,  the  albuminous  constituent  undergoes  some  change  in  passing 
through  the  liver,  by  which  it  is  rendered  more  fit  to  enter  the  general  circula- 
tion; for  it  has  been  found  by  M.  Bernard,  that  whilst  a  solution  of  the  albu- 
men of  the  egg,  injected  into  the  jugular  vein,  speedily  occasioned  a  transuda- 
tion  of  albumen  into  the  urine,  no  such  transudation  occurred  when  a  similar 
solution  was  injected  into  the  vena  portse.3 — According  to  Prof.  Lehmann,  the 
blood  of  the  hepatic  vein  further  differs  from  that  of  the  portal  in  the  follow- 
ing particulars.  " It  is  far  poorer  in  water;  so  that,  assuming  the  solid  con- 
stituents of  the  blood  to  be  equal  in  both  kinds  of  blood,  the  quantity  of  water 
in  the  blood  of  the  portal  vein  is  to  that  in  the  blood  of  the  hepatic  vein  as  4  :  3 
during  digestion  and  when  not  much  drink  has  been  taken,  and  sometimes  as 
much  as  12  : 5  after  digestion  has  been  fully  accomplished.  The  clot  of  the 
blood  of  the  hepatic  vein  is  bulky,  and  readily  breaks  down ;  whilst  34  parts  of 
serum  are  separated  from  100  parts  of  portal  blood,  only  15  are  separated  from 
100  parts  of  the  blood  of  the  hepatic  vein.  The  blood  of  the  hepatic  vein  is 
far  richer  in  blood-cells,  both  colored  and  colorless,  than  that  of  the  portal  vein ; 
the  colorless  corpuscles  occur  in  the  most  varied  shapes  and  sizes;  the  colored 
are  seen  in  heaps  of  a  distinct  violet  color,  and  their  capsules  are  less  readily 

1  '  <L' Union  Medicale,"  Sept  23,  1850.     M.  Bernard  does  not  give  any  details  on  this 
point;  and  he  does  not  seem  to  have  made  allowance  for  the  admixture  of  the  blood  of  the 
hepatic  artery  with  that  of  the  portal  vein. 

2  "Gazette  Medicale,"  1850. 


184  OF   THE   BLOOD. 

destroyed  by  water  than  are  those  of  the  blood  of  most  other  vessels ;  while  in 
the  blood  of  the  portal  vein  there  are  141  parts  of  moist  blood-cells  to  100 
parts  of  plasma,  in  the  blood  of  the  hepatic  vein  there  are  317  parts  of  moist 
blood-cells  to  100  of  plasma.  The  cells  in  the  blood  of  the  hepatic  veins  are 
poorer  in  fat  and  in  salts,  and  especially  in  haematin,  or  at  least  iron,  but  some- 
what richer  in  extractive  matters.  The  specific  gravity  is  higher  than  that  of 
the  cells  of  the  portal  blood,  notwithstanding  the  diminished  quantity  of  iron. 
The  plasma  of  the  blood  of  the  hepatic  veins  is  far  denser  than  that  of  the  blood  of 
the  portal  vein,  for  it  contains  a  much  larger  amount  of  solid  constituents  gene- 
rally, although  little  or  no  fibrin  is  to  be  found  in  it  (?).  While  8.4  parts  of 
solid  matter  correspond  to  100  of  water  in  the  serum  of  portal  blood,  there  are 
11.8  parts  of  solid  matter  to  an  equal  quantity  of  water  in  the  serum  of  the 
blood  of  the  hepatic  veins.  If  we  compare  the  solid  constituents  of  the  serum 
of  both  kinds  of  blood,  we  find  less  albumen  and  fat,  and  far  less  salts,  in  the 
blood  of  the  hepatic  veins,  while  the  quantity  of  extractive  matter,  including 
sugar,  is  perceptibly  augmented."1 — It  cannot  be  doubted  that,  when  the  secre- 
tion of  urine  is  proceeding  with  rapidity,  the  blood  of  the  renal  vein  must  con- 
tain a  smaller  proportion  of  water  than  that  of  the  renal  artery,  and  that  the 
quantity  of  salines  also  must  be  diminished;  since  a  separation  of  these  ingre- 
dients takes  place  in  the  passage  of  the  blood  through  the  renal  capillaries.  So 
far  as  regards  the  quantity  of  water,  this  d  priori  conclusion  has  been  confirmed 
by  the  analyses  of  Simon,  who  found  790  parts  of  water  in  1000  of  blood 
drawn  from  the  renal  artery,  and  only  778  in  blood  drawn  from  the  renal  vein 
of  the  same  animal.2  The  proportion  of  salts,  however,  has  not  been  analyti- 
cally determined  to  be  different. 

170.  Alterations  in  the  Composition  of  the  Blood  in  Disease. — Under  this 
head  it  is  intended  here  to  consider,  not  the  state  of  the  Blood  in  every  princi- 
pal type  of  disease  (which  it  is  the  duty  of  the  Pathologist  to  investigate),  but 
the  most  important  facts  which  the  study  of  its  morbid  conditions  has  afforded, 
towards  the  determination  of  the  conditions  under  which  decided  variations 
take  place  in  the  quantity  or  quality  of  its  principal  components,  and  of  the 
effects  which  those  variations  produce  upon  the  system  at  large.  The  first  series 
of  such  connected  researches,  as  afford  the  requisite  materials  for  this  inquiry, 
was  that  of  MM.  Andral  and  Gravarret,3  which  is  still  cf  standard  value;  this 
was  followed  by  the  investigations  of  MM.  Becquerel  and  Rodier;4  and  many 
additional  analyses  have  been  made  by  Popp,  Simon,  and  other  observers.  For 
the  purpose  of  comparison,  however,  as  already  remarked,  it  is  desirable  to  em- 
ploy those  results  only  which  have  been  obtained  by  processes  essentially  the 
same ;  and  hence  the  following  summary  will  be  chiefly  based  on  the  statements 
of  the  French  experimenters  whose  researches  have  been  just  referred  to. — It  is 
necessary,  however,  in  the  first  place,  to  assume  some  standard  of  composition, 
which  may  be  regarded  as  sufficiently  characteristic  of  health,  to  lead  us  to  rank 
any  variation  which  passes  beyond  its  limits  as  essentially  morbid;  and  this 
standard  must  be  fixed  according  to  the  method  of  analysis  employed.  Thus, 
although  it  has  been  shown  (§  154)  that  the  calculation  of  the  proportionals  of 
the  principal  constituents  of  the  blood,  from  the  results  obtained  according  to 
the  method  of  MM.  Andral  and  Gavarret,  must  be  held  to  be  in  itself  errone- 
ous, yet  as  the  same  method  was  followed  in  all  the  analyses  of  morbid  blood 
made  by  them  and  their  successors,  the  requisite  standard  must  be  erected  upon 
this  foundation ;  and  the  following  may  thus  be  considered  as  the  normal  range 

1  "Lehrbuch  der  Physiologischen  Chemie,"  band  ii.  p.  250. 

2  "Animal  Chemistry,"  translated  by  Dr.  Day,  vol.  i.  p.  214. 

3  "Essai  d'Hsematologie  Pathologique." 

«  "  Recherches  sur  la  Composition  du  Sang  dans  1'Etat  de  Sante  et  dans  1'Etat  de  Maladie." 


ITS   PHYSICAL,    CHEMICAL,    AND    STRUCTURAL   CHARACTERS.       185 


the  principal  constituents  of  the  blood  in  health,  according  to 
.ode  of  estimating  them  (§  152). 


of  variation  for 
the  foregoing  mode 

Fibrin        .    '     ,  .  .         .  from  2  to         3£  parts  per  1000. 

Red  Corpuscles  .  .  .         .  •"  110  "  152           "           " 

Solids  of  Serum  .  -  .         .        "  72  «  88 

Water        .         .  .  &&«  .        "  760  "  815           "           " 

171.  The  first  of  these  components  whose  variations  we  shall  consider,  is 
Fibrin;  the  estimate  of  which,  however,  is  open  to  an  important  fallacy,  that 
has  not  been  sufficiently  guarded  against — namely,  the  admixture  of  the  Color- 
less corpuscles.     "These,"  as  Mr.  Paget  correctly  remarks,  "cannot,  by  any 
mode   of  analysis  yet  invented,  be  separated  from  the  fibrin  of  mammalian 
blood  ;  their  composition  is  unknown,  but  their  weight  is  always  included  in  the 
estimate  of  the  fibrin.    In  health,  they  may,  perhaps,  add  too  little  to  its  weight 
to  merit  consideration;  but  in  many  diseases,  especially  in  inflammatory  and 
other  blood-diseases  in  which  the  fibrin  is  said  to  be  increased,  these  corpuscles 
become  so  numerous  that  a  large  proportion  of  the  supposed  increase  of  the 
fibrin  must  be  due  to  their  being  weighed  with  it.     On  this  account,  all  the 
statements  respecting  the  increase  of  fibrin  in  certain  diseases  need  revision."1 
Some  idea  may  probably  be  formed  of  the  relative  proportion  of  fibrin  and 
colorless  corpuscles,  in  the  colorless  coagulum  obtained  by  stirring  the  blood  or 
by  washing  the  ordinary  clot,  or  in  that  which  forms  the  "buffy  coat"  (§  189), 
by  attending  to  its  texture;  for  where  this  is  unusually  firm  and  almost  leathery, 
as  it  commonly  is  in  the  blood  of  a  person  suffering  under  a  "sthenic"  inflamma- 
tion, either  the  proportion  of  fibrin  must  be  augmented,  or  its  plasticity  must 
be  increased,  or  both  conditions  must  co-exist;  whilst,  on  the  other  hand,  when 
the  colorless  clot,  though  bulky,  is  deficient  in  tenacity  and  is  easily  broken 
down  between  the  fingers,  as  happens  with  that  of  blood  drawn  from  tubercular 
subjects  when  no  inflammation  is  present,  the  increase  is  probably  due  rather  to 
an  augmentation  in  the  colorless  corpuscles,  than  to  that  of  the  fibrin. — In  the 
results  of  the  analyses  now  to  be  stated,  it  must  be  borne  in  mind  that  the  term 
"fibrin"  really  designates  the  "colorless  coagulum"  of  spontaneous  formation, 
whatever  may  be  its  composition. 

172.  The  most  important  fact  substantiated  by  Andral  is  one  that  had  been 
previously  suspected — the  invariable  increase  in  the  quantity  of  Fibrin  during 
acute  Inflammatory  affections;  the  increase  being  strictly  proportional  to  the 
intensity  of  the  inflammation,  and  to  the  degree  of  symptomatic  fever  accom- 
panying it.     "The  augmentation  of  the  quantity  of  Fibrin  is  so  certain  a  sign 
of  Inflammation,  that  if  we  find  more  than  5  parts  of  fibrin  in  1000,  in  the 
course  of  any  disease,  we  may  positively  affirm  that  some  local  inflammation 
exists."     Several  cases  are  mentioned,  in  which  an  increase  to  7  or  7z  parts 
took  place,  without  any  apparent  cause;  but  in  which  it  afterwards  proved  that 
severe  local  inflammation  had  been  present;  and  thus  we  are  furnished  with  a 
pathognomonic  sign  of  great  importance.     The  average  proportion  of  Fibrin  in 
Inflammation  may  be  estimated  at  7;  the  minimum  at  5;  the  maximum  at  13.3. 
The  greatest  augmentation  is  seen  in  Pneumonia  and  Acute  Rheumatism.     It 
does  not  appear  that  in  robust  athletic  persons,  the  proportion  of  Fibrin  is 
greater  than  in  those  of  feeble  constitution;  in  the  latter  it  is  the  Corpuscles 
that  are  deficient :  and  it  is  rather  from  this  disproportion,  than  from  an  abso- 
lute excess   of  Fibrin,  that  their  greater  liability  to  Inflammatory  affections 
arises.     Diseases  which  commence  at  the  same  time  as  the  Inflammation,  or 
which  coexist  with  it,  do  not  prevent  the  characteristic  increase  of  the  Fibrin; 
thus  in  Chlorotic  females,  the  proportion  rises  to  6  or  7,  under  this  influence. 

1  Kirkes  and  Paget's  "Manual  of  Physiology,"  p.  57. 


186  OF  THE   BLOOD. 

The  augmentation  is  observed  at  the  very  outset  of  the  affection  ;  the  quantity 
increases  with  its  progress ;  and  a  decrease  shows  itself  when  the  disease  begins 
to  abate.1  When  the  disease  presents  alternations  of  increase  and  decline, 
these  are  marked  by  precisely  corresponding  changes  in  the  quantity  of  Fibrin. 
An  augmentation  is  commonly  observable  during  the  advanced  stage  of  Phthisis, 
in  spite  of  the  deterioration  which  the  blood  must  then  have  undergone ;  this 
is  probably  dependent  upon  the  development  of  local  inflammation  around  the 
tubercular  deposits.  In  one  of  Popp's  observations,  the  proportion  of  Fibrin 
in  the  blood  of  a  Phthisical  patient  was  not  less  than  10.7. — Some  experiments 
performed  by  M.  Andral  on  the  blood  of  pregnant  women  seem  to  lead  to  the 
conclusion  that,  during  the  first  six  months,  the  Fibrin  is  below  the  normal 
standard;  and  that  it  subsequently  varies,  usually  undergoing  an  augmentation 
between  the  sixth  and  seventh,  and  the  eighth  and  ninth  months.  There  is 
also  a  diminution  in  the  Corpuscles;  and  these  circumstances  combined  favor 
the  production  of  the  "buffy  coat"  (§  190).  These  observations  are  confirmed 
by  those  of  MM.  Becquerel  and  Rodier. 

173.  It  appears  obvious,  from  what  has  been  just  stated,  that  the  increase  in 
the  quantity  of  Fibrin  is  not  dependent  upon  the  febrile  condition,  which  is 
secondary  to  the  local  inflammation,  but  upon  the  Inflammation  itself.  This 
conclusion  is  confirmed  by  the  interesting  fact  that,  in  idiopathic  Fever,  the 
proportion  of  Fibrin  is  diminished,  instead  of  undergoing  an  increase.  This 
diminution  was  constantly  observed  by  Andral  in  the  premonitory  stage  of 
Continued  Fever;  in  some  instances  the  amount  was  no  more  than  1.6  parts 
in  1000.  The  proportion  of  Corpuscles  was  found  to  have  usually,  but  not 
constantly,  undergone  an  increase;  as  had  also  that  of  the. solid  parts  of  the 
Serum.  In  ordinary  Continued  Fever,  in  which  there  was  no  evident  compli- 
cation from  local  disease,  the  quantity  of  Fibrin  varied  from  4.2  to  2.2;  that 
of  the  Corpuscles  from  185.1  to  103.6  (excluding  a  case  in  which  their  amount 
was  only  82.5,  which  was  that  of  a  Chlorotic  female);  that  of  the  solid  matter 
of  the  Serum,  from  98.7  to  90.9;  and  that  of  the  Water  from  725.6  to  851.9. 
Hence  the  quantity  of  solid  matter  appears  to  be  usually  increased;  but  the 
peculiar  condition  of  the  blood  in  this  disease  may  probably  be  stated  to  be  (so 
far  as  regards  the  proportions  of  its  principal  constituents)  a  diminution  of  the 
Fibrin  in  proportion  to  the  Red  Corpuscles.  When,  however,  a  local  Inflam- 
matory affection  develops  itself  during  the  course  of  the  Fever,  the  amount  of 
Fibrin  increases;  but  its  augmentation  seems  to  be  kept  down  by  the  febrile 
condition.  In  Typhoid  Fever,3  the  decrease  in  the  proportion  of  Fibrin  is 
much  more  decidedly  marked ;  this  does  not  depend  upon  abstinence ;  for  it 
ceases  as  soon  as  a  favorable  change  occurs  in  the  disease,  long  before  the  effect 
of  food  could  show  itself.  In  the  various  cases  examined  by  Andral,  the  blood 
furnished  a  maximum  of  3.7  of  fibrin,  and  a  minimum  of  0.9 ;  in  this  last  case, 
the  typhoid  condition  existed  in  extreme  intensity,  yet  the  patient  recovered. 
The  proportion  of  Corpuscles  varies  considerably ;  in  an  early  stage  of  the  dis- 
ease it  is  usually  found  to  be  absolutely  high ;  and  it  always  remains  high  rela- 

1  By  experiments  on  animals,  M.  Andral  has  ascertained  that  no  circumstance  of  pre- 
vious debility  or  privation  prevents  this  characteristic  change.     Having  ascertained  the 
amount  of  fibrin  in  the  blood  of  three  dogs  to  be  2.3,  2.2,  and  1.6  (the  natural  range  for 
these  animals),  he  deprived  them,  completely  or  partially,  of  food.    On  the  fourteenth  day, 
the  proportion  of  fibrin  had  risen,  in  the  first  to  4.5,  and  in  the  second  to  4;  these  animals 
had  no  food.     In  the  third  dog,  which  was  supplied  with  a  very  small  quantity  of  food 
daily,  the  same  condition  developed  itself  at  a  later  period ;  the  blood  on  the  fourteenth 
day  exhibiting  only  1.8  parts  of  fibrin;  but  on  the  twenty-second  day  presenting  3.3 
parts. — In  all  these  instances,  the  elevation  in  the  proportion  of  Fibrin  was  coincident  with 
Inflammatory  changes  in  the  stomach. 

2  M.  Andral  confines  this  term  to  the  species  characterized  by  ulceration  of  the  mucous 
follicles  of  the  intestinal  canal. 


ITS   PHYSICAL,    CHEMICAL,   AND   STRUCTURAL   CHARACTERS.       187 

tively  to  the  amount  of  fibrin.  In  Typhoid  Fever,  then,  the  abnormal  condition 
of  the  blood,  in  regard  to  the  disproportion  between  the  corpuscles  and  the  fibrin, 
is  more  strongly  marked  than  in  ordinary  continued  fever ;  yet  the  usual  aug- 
mentation of  fibrin  will  take  place,  if  a  local  inflammation  develops  itself.  In 
"  putrid"  or  "  malignant"  fevers,  there  appears  to  be  a  very  marked  diminution, 
not  only  in  the  fibrin,  but  in  the  other  solid  constituents  of  the  blood  \  and  in 
their  advanced  stages,  the  blood  may  entirely  lose  its  power  of  coagulation. 
Thus  in  a  case  of  "  typhus  abdominalis,"  in  which  the  blood  was  analyzed  by 
Simon,  he  found  only  112.5  parts  of  solid  matter,  of  which  54  parts  were  albu- 
men, the  corpuscles  only  constituting  47?  parts,  and  the  fibrin  being  altogether 
deficient.  In  the  Exanthematous  Fevers,  it  does  not  appear  that  the  proportion 
between  the  fibrin  and  the  corpuscles  undergoes  so  striking  a  change  as  in  ordi- 
nary continued  fever ;  but  the  number  of  cases  examined  has  been  too  small  to 
admit  of  decided  conclusions.  It  is  evident,  however,  that  the  specific  Inflam- 
mations proper  to,  and  characteristic  of,  these  Fevers,  have  not  the  same  effect 
in  occasioning  an  increase  of  the  Fibrin,  as  an  intercurrent  Inflammation  of  an 
extraneous  character.  It  has  been  asserted  that  the  proportion  of  Fibrin  is 
diminished  in  Scurvy;  but  this,  from  the  analyses  of  MM.  Becquerel  and 
Rodier,  Chatin,  and  Bouvier,1  and  Mr.  Busk,3  appears  not  to  be  the  case,  the 
proportion  of  fibrin  being  rather  above  than  below  the  normal  average.  In 
Cholera,  however,  a  reduction  in  the  coagulable  element  of  the  blood  seems  to 
be  an  almost  constant  occurrence ;  and  in  some  instances,  the  blood,  although 
loaded  with  solid  matter,  has  scarcely  coagulated  at  all.  Of  the  blood  drawn 
during  life,  it  has  been  observed  that  the  clot  is  loose  and  grumous,  often  not 
shrinking  and  expelling  serum  ;  and  that  this  change  presents  itself  in  a  degree 
corresponding  to  the  severity  and  advanced  stage  of  the  disease.  And  when 
the  blood  has  been  removed  from  the  body  after  death,  the  clots  have  been  found 
loose  and  fragile  in  texture,  sometimes  almost  semi-fluid.3  It  appears  from  the 
experiments  of  Magendie,  that  one  of  the  effects  of  a  diminution  in  the  propor- 
tion of  Fibrin  is  a  tendency  to  the  occurrence  of  Hemorrhage  or  of  Congestion, 
either  in  the  parenchymatous  tissue,  or  on  the  surface  of  membranes :  and  these 
conditions  are  well  known  to  be  a  frequent  occurrence,  as  complications  of  many 
of  the  above  disorders.  A  marked  diminution  of  Fibrin  was  noticed  also,  by 
M.  Andral,  in  many  cases  of  Cerebral  Congestion,  which  commences  with  head- 
ache, vertigo,  and  tendency  to  epistaxis,  and  not  unfrequently  passes  into  coma 
and  apoplexy.  In  Apoplexy,  the  diminution  of  Fibrin  was  still  more  striking ; 
and  in  general,  there  was  found  to  be  an  increase  of  the  Corpuscles.  In  one 
instance,  the  quantity  of  Fibrin  on  the  second  day  of  the  attack  was  found  to 
have  fallen  to  1.9,  whilst  that  of  the  Corpuscles  had  risen  to  176.5;  but  on  the 
third  day,  when  the  patient's  consciousness  began  to  return,  the  quantity  of 
Fibrin  was  3.5,  whilst  that  of  the  Corpuscles  had  fallen  to  137.7.  It  would  seem 
from  the  great  change  in  the  character  of  the  Blood,  which  was  noticed  in  this 
and  in  other  instances,  that  the  want  of  due  proportion  between  the  Fibrin  and 
the  Corpuscles  may  have  been  the  cause,  rather  than  the  effect,  of  the  Apoplec- 
tic attack.  In  a  case  of  Purpura  Haemorrhagica  in  which  the  blood  was  ana- 
lyzed by  Routier,4  the  proportion  of  corpuscles  was  normal  (nearly  122  parts  in 
1000),  whilst  the  fibrin  only  amounted  to  0.9  parts  in  1000. 

174.  The  amount  of  Red  Corpuscles  seems  to  be  subject  to  greater  variation 
within  the  limits  of  ordinary  health,  than  is  that  of  fibrin.  In  the  condition 
which  is  ordinarily  termed  a  highly  sanguineous  temperament,  or  Plethora,  it 


1  "  Journ.  de  Chimie  Medicale,"  Mars,  1848. 

2  "Library  of  Medicine,"  vol.  v.  p.  90. 


3  See  Dr.  Parkes's  "Researches  into  the  Pathology  and  Treatment  of  the  Asiatic  or 
Algide  Cholera,"  pp.  32,  73. 

4  "Gazette  des  Hopitaux,"  torn.  vi.  No.  90. 


188  OF   THE    BLOOD. 

is  chiefly  the  entire  mass  of  the  blood  that  undergoes  an  increase ;  but  whatever 
excess  there  may  be  in  the  proportion  of  its  solid  constituents,  this  affects  the 
Corpuscles  rather  than  the  fibrin.  Plethoric  persons  are  not  more  prone  to  In- 
flammation, than  are  those  of  weaker  constitution ;  bul,  they  are  liable  to  Con- 
gestion, especially  of  the  brain,  and  to  Apoplexy  or  other  Hemorrhage.  The 
effect  of  Bleeding  in  diminishing  this  tendency  is  now  intelligible ;  since  we 
know  that  loss  of  blood  reduces  the  proportion  of  Corpuscles. — On  the  other 
hand,  in  that  temperament,1  which,  when  exaggerated,  becomes  Anaemia,  there  is 
a  marked  diminution  of  the  Corpuscles ;  this  temperament  may  lead  to  two 
different  conditions  of  the  system.  In  Chlorosis,  the  Red  Corpuscles  are  dimin- 
ished, whilst  the  Fibrin  remains  the  same ;  so  that  the  clot,  though  small,  is 
firm,  and  not  unfrequently  exhibits  the  buffy  coat;  in  some  extreme  cases  "of 
this  disease,  the  Corpuscles  have  been  found  as  low  as  27.  The  influence  of 
the  remedial  administration  of  iron  in  increasing  the  quantity  of  Corpuscles 
was  rendered  extremely  perceptible  by  Andral's  analyses;  in  one  instance, 
after  iron  had  been  taken  for  a  short  time,  the  proportion  of  Corpuscles  was 
found  to  have  risen  from  49.7  to  64.3 ;  whilst  in  another,  in  which  it  had  been 
longer  continued,  it  had  risen  from  46.6  to  95.7.  On  the  other  hand,  Bleeding 
reduced  still  lower  the  proportion  of  Corpuscles ;  thus,  in  one  instance,  their 
amount  was  found,  on  a  second  bleeding,  to  have  sunk  from  62.8  to  49.  The 
full  proportion  of  fibrin  in  the  blood  of  Chlorotic  patients  seems  to  account  for 
the  infrequency  of  Hemorrhage  in  them ;  whilst  it  also  leads  us  to  perceive  that 
they  may  be,  equally  with  others,  the  subjects  of  acute  Inflammation,  which  we 
know'te-  be  the  fact.  A  diminution  of  Corpuscles  may  also  co-exist  with  a  dimi- 
nution in  the  amount,  or  in  the  degree  of  elaboration,  of  the  fibrin ;  and  this 
condition  seems  to  be  characteristic  of  scrofula.  Andral  has  noticed  a  diminu- 
tion in  the  proportion  of  Red  Corpuscles  in  other  Cachectic  states,  resulting 
from  the  influence  of  various  depressing  causes  on  the  nutritive  powers ;  as  in  a 
ease  of  Diabetes  Mellitus,  in  which  the  patient  was  much  exhausted;  a  case  of 
Aneurismal  dilatation  of  the  Heart,  inducing  Dropsy ;  and  in  several  cases  of 
Cachexia  Saturnina.  The  proportion  of  Red  Corpuscles  seems  constantly  to 
undergo  a  marked  diminution  in  Scurvy :  and  has  been  found,  in  some  cases  of 
this  disease,  as  low  as  in  intense  Anaemia.  The  same  may  be  said  of  the  advanced 
stage  of  Bright' s  disease  of  the  Kidney,  and  of  "Leucocythaemia."  A  very  rapid 
disintegration  of  the  Red  Corpuscles  appears  sometimes  to  take  place  when  a 
morbid  poison  is  present  in  the  blood,  or  when  its  composition  has  been  seriously 
affected  by  the  loss  of  its  other  constituents.  Thus  Dr.  C.  J.  B.  Williams3  men- 
tions a  case  of  Albuminuria  proving  fatal  in  six  days,  with  effusion  of  pus  into 
the  joints  the  day  before  death,  in  which  the  coloring  matter  was  found  to  be 
dissolved  in  the  liquor  sanguinis,  scarcely  any  perfect  corpuscles  being  left. 
He  has  also  observed  a  similar  total  destruction  of  the  blood-disks  in  a  case  of 
malignant  scarlatina  with  purpura ;  and  has  met  with  indications  of  a  partial 
destruction  of  them  in  acute  purpura  connected  with  jaundice,  and  in  cases  of 
functional  derangement  of  the  liver. 

175.  A  marked  increase  in  the  proportion  of  the  Colorless  Corpuscles  has  been 
frequently  observed  in  the  blood  of  persons  suffering  under  inflammatory  diseases; 
and  has  been  supposed  by  some  Pathologists  to  be  an  essential  condition  of  the 
inflammatory  state.  More  extended  observation  has  proved,  however,  that  such 
an  increase  is  by  no  means  constant,  and  that  it  shows  itself  especially  in  the 
blood  of  cachectic  subjects,  in  whom  (particularly  those  of  the  tuberculous  dia- 
thesis) it  seems  to  take  place  independently  of  Inflammation. — Attention  has 

1  The  term  lymphatic  has  been  applied  to  this  temperament ;  by  which  term  was  meant 
a  predominance  of  lymph  in  the  absorbent  vessels. 

2  "Principles  of  Medicine,"  3d  Am.  Ed.  p.  50. 


ITS   PHYSICAL,   CHEMICAL,   AND   STRUCTURAL   CHARACTERS.       189 

recently  been  drawn  by  Prof.  J.  H.  Bennett1  to  a  condition  of  the  Blood,  which 
is  especially  characterized  by  a  marked  excess  of  these  bodies,  and  which  he 
has  designated  by  the  term  Leucocythaemia  (white-cell-blood).  This  condition 
has  been  detected  in  the  blood  of  a  considerable  number  of  individuals  suffering 
under  diseases  (most  commonly  enlargement)  of  the  Spleen,  Liver,  and  Lym- 
phatic glands,  either  separately  or  in  conjunction  ;  but  it  has  not  yet  been  de- 
termined how  far  it  is  constantly  associated  with  any  of  these  abnormal  con- 
ditions. In  all  cases  in  which  the  blood  has  been  analyzed,  its  specific  gravity 
has  been  found  very  low,  and  the  total  amount  of  solids  small  (being  in  one 
instance  only  119  parts  in  1000) ;  but  the  fibrin  is  almost  invariably  above  the 
average,  having  in  one  instance  risen  to  7.08.  The  total  amount  of  Corpuscles 
is  considerably  reduced,  having  ranged  in  six  analyses  between  49.7  and  101.6, 
the  average  having  been  82.36 ;  and  so  large  a  proportion  of  the  whole  mass 
was  in  some  instances  determined  by  the  microscope  (no  means  being  at  present 
known,  of  physically  separating  these  two  orders  of  bodies)  to  be  of  the  color- 
less kind,  that  the  amount  of  red  corpuscles  must  have  been  exceedingly  small. 
The  proportion  of  solids  in  the  serum  does  not  seem  to  undergo  any  decided 
alteration.  No  marked  change  in  the  condition  of  the  blood  could  be  observed 
during  the  progress  of  any  of  the  cases  which  were  under  observation  for  long 
periods  ;  and  the  circumstances  under  which  the  commencement  of  this  morbid 
perversion  occurs  are  still  quite  unknown.  When  the  colorless  corpuscles  are 
present  in  very  large  amount,  they  give  to  the  colorless  coagula  found  in  the 
heart  and  large  vessels  after  death,  a  dull  whitish  color,  and  render  them  very 
friable. 

176.  The  quantity  of  Albumen  in  the  blood  seems  to  vary  less  than  that  of 
most  of  its  other  constituents.  The  proportion  which  it  bears  to  the  water  of 
the  serum  is  of  course  elevated  by  anything  which  diminishes  the  latter ;  and 
thus  we  find  it  high  in  cholera  after  profuse  discharges  of  fluid  from  the  intes- 
tinal canal,  and  in  other  cases  in  which  there  has  been  an  unusual  drain  upon 
the  liquid  part  of  the  blood,  provided  that  the  albumen  does  not  pass  off  with 
it,  as  sometimes  happens.  Where  some  special  cause  is  in  operation,  which 
favors  the  escape  of  the  albumen  from  the  circulating  current  (as  happens  in 
various  forms  of  Albuminuria,  but  especially  in  the  advanced  stage  of  "  Bright' s 
disease"),  the  amount  of  albumen  in  the  serum  is  reduced  below  the  normal 
standard.  Thus  Dr.  Christison  found  the  entire  solids  of  the  serum  to  be  re- 
duced in  some  instances  to  55  or  even  52  parts  in  1000,  his  estimate  of  their 
normal  amount  being  83.4;  and  he  found  the  specific  gravity  of  the  serum  to 
fall  as  low  as  1020  or  even  1019,  the  normal  standard  being  from  1029  to  1031. 
According  to  Andral,  the  diminution  in  the  amount  of  Albumen  in  the  Serum 
is  exactly  proportional  to  the  quantity  contained  in  the  Urine.3  The  proportion 

1  See  his  successive  Papers  in  the  "Edinb.  Monthly  Journal,"  for  1851. 

2  A  case  is  related  by  Andral,  under  this  head,  which  affords  an  interesting  exemplifica- 
tion of  the  general  facts  that  have  been  attained  by  his  investigations.     A  woman  who 
had  been  suffering  from  Erysipelas  of  the  face,  and  who  lost  blood  both  by  venesection 
and  by  leeches,  became  the  subject  of  Albuminuria.     The  blood  drawn  at  this  time  ex- 
hibited a  considerable  diminution  in  the  proportion  of  Corpuscles,  as  well  as  of  Albumen, 
a  fact  which  the  previous  loss  of  blood  fully  accounted  for.     After  a  short  period,  during 
which  she  had  been  allowed  a  fuller  diet,  another  experimental  bleeding  exhibited  an  in- 
crease in  the  proportion  of  Corpuscles.     Some  time  afterwards,  when  the  Albumen  had 
disappeared  from  the  Urine,  some  more  blood  was  drawn ;  and  it  was  then  observed  that 
the  Albumen  of  the  Serum  had  returned  to  its  due  proportion,  but  that  the  Corpuscles  had 
again  diminished,  whilst  there  was  a  marked  increase  in  the  quantity  of  Fibrin.     This 
alteration  was  fully  accounted  for  by  the  fact,  that,  in  the  interval,  several  Lymphatic 
ganglia  in  the  neck  had  been  inflamed  and  had  suppurated ;  and  that  the  patient  had  been 
again  placed  on  very  low  diet.     ''Thus,"  observes  Andral,   "we  were  enabled  to  give  a 
complete  explanation  of  the  remarkable  oscillations  which  were  presented,  in  the  propor- 
tion of  the  different  elements  of  the  blood  drawn  at  three  different  times  from  the  same 


190  OF   THE   BLOOD. 

of  fatty  matter  in  the  serum,  and  especially  of  the  cholesterin,  has  been  found 
by  MM.  Becquerel  and  Rodier  to  undergo  an  increase  at  the  commencement  of 
most  acute  diseases ;  and  they  have  also  observed  an  increase  of  fat,  and  especially 
of  cholesterin,  in  chronic  diseases  of  the  liver,  in  Bright's  disease  of  the  kidney, 
and  in  tuberculosis.  The  quantity  of  fat  in  the  blood  sometimes  undergoes  such 
an  augmentation  as  to  give  to  the  serum  a  constant  "  milkiness."  This  has  been 
observed  by  Marcet  in  a  case  of  diabetes,  by  Traill  in  hepatitis,  by  Christison 
in  dropsy,  icterus,  and  nephritis,  by  Zanarelli  in  pneumonia,  and  by  Sion  in 
mammary  abscess.  In  Dr.  Traill' s  case,  the  whole  amount  of  solid  matter  in 
the  serum  was  211  parts  in  1000;  as  much  as  157  parts  being  albumen,  whilst 
45  were  fat.  In  Zanarelli' s  case,  the  blood  contained  so  small  a  proportion  of 
red  corpuscles  that  it  seemed  milky  when  it  first  flowed  ;*  and  it  did  not  under- 
go a  regular  coagulation,  but  merely  separated  into  a  thicker  and  a  thinner  por- 
tion. This  blood  only  contained  95  parts  of  solid  constituents  in  1000;  and  10 
parts  of  these  consisted  of  fatty  matter,  and  9  parts  of  extractive  and  salines ; 
so  that  the  whole  amount  of  fibrin,  corpuscles,  and  albumen  was  only  76  parts. 
In  Dr.  Sion's  case,  also,  the  blood  itself  was  quite  milky;  it  underwent  no 
coagulation ;  and  only  a  very  small  quantity  of  coloring  matter  was  deposited 
when  it  was  allowed  to  stand.  This  blood  was  found  by  Lecanu  to  contain  206 
parts  of  solid  constituents  in  1000;  but  of  these  no  less  than  117  parts  were 
fat,  the  remainder  consisting  of  albumen  (64  parts),  and  of  extractive  and 
salines  (25  parts).  No  fibrin  could  be  found,  and  the  quantity  of  haemato- 
globulin  was  inappreciable.1  Such  a  fluid  must  be  considered  rather  as  chyle 
than  as  blood;  and,  in  the  entire  absence  of  coagulating  power,  corresponds 
rather  with  chyle  when  first  absorbed,  than  with  that  which  is  usually  delivered 
by  the  thoracic  duct  (CHAP.  vni.).  Little  is  known  with  certainty  regarding 
the  variations  of  the  alkaline  salts  in  the  blood  in  different  diseases.  The 
analyses  which  have  been  made,  however,  are  considered  by  Prof.  Lehmann3  to 
indicate  that  in  very  severe  inflammations  they  are  very  much  diminished ; 
whilst  they  are  much  increased  in  the  acute  exanthemata  and  in  typhus,  in  dysen- 
tery, Bright's  disease,  and  all  forms  of  dropsy  and  hydrsemia;  and  are  often 
doubled  in  quantity  in  diseases  depending  upon  malarious  influences,  such  as 
endemic  dysentery,  malignant  forms  of  intermittent  fever,  &c.  Although  a 
large  quantity  of  saline  matter  usually  passes  off  from  the  blood  in  Cholera,  yet 
the  proportion  of  water  discharged  is  so  much  greater,  that,  as  appears  from  the 
analyses  of  Dr.  Garrod,  the  per-centage  of  salines  in  the  blood  is  rather  increased 
than  diminished.3 

177.  The  proportion  of  Water  in  the  blood  will  of  course  vary  reciprocally 
with  that  of  the  solid  constituents ;  and  will  be  especially  augmented  when 
there  is  a  marked  diminution  in  the  amount  of  red  corpuscles.  When  there  is 
an  excessive  and  constant  drain  upon  it,  as  in  diabetes,  there  is  at  the  same  time 
such  a  craving  for  liquids,  as  causes  the  quantity  ingested  to  supply  the  deficiency 
occasioned  by  its  removal ;  so  that  the  mass  of  the  blood  is  not  thereby  dimin- 
ished. In  Cholera,  however,  the  case  is  different;  for  in  that  form  of  the  dis- 
ease attended  with  copious  discharges,  the  reduction  in  the  liquid  constituent  of 

individual ;  and  thus  it  is  that,  the  more  extended  are  our  inquiries,  the  more  easy  does 
it  become  to  refer  to  general  principles  the  causes  of  all  those  changes  in  the  composition 
of  the  blood,  which,  from  the  frequency  and  rapidity  with  which  they  occur,  seem  at  first 
sight  to  baffle  all  rules,  and  to  take  place,  as  it  were,  at  random.  In  the  midst  of  this  appa- 
rent disorder,  there  is  but  the  fulfilment  of  laws;  and  in  order  to  obtain  these,  it  is  only 
necessary  to  strip  the  phenomena  of  their  complications,  and  reduce  them  to  their  simplest 
form." 

1  This  remarkable  case  is  cited  in  Simon's  "Animal  Chemistry,"  vol.  i.  p.  333,  from 
the  "Lancette  Francaise,"  1835,  No.  49. 

2  "  Lehrbuch  der  physiologischen  Chemie,"  band  ii.  p.  242. 

3  "  London  Journal  of  Medicine,"  May,  1849. 


191 

the  blood  becomes  very  marked,  however  large  may  be  the  quantity  of  water 
ingested.  This  is  remarkably  shown  by  the  analyses  of  Lecanu,1  who  found 
the  proportion  of  solid  constituents  in  some  instances  even  to  exceed  that  of  the 
water. 

Solid  constituents              .         .         251  330  340  520 

Water 749  670  660  480 

No  such  degree  of  reduction  has  been  observed  by  others ;  still  the  general  fact 
is,  that  the  proportion  of  water  is  considerably  diminished. 

178.  That  the  Blood  is  subject  to  a  great  variety  of  other  morbid  alterations, 
which  are  sometimes  the  causes,  and  sometimes  the  results,  of  Disease,  cannot 
be  for  a  moment  doubted.     But  our  knowledge  of  the  nature  of  these  changes 
is  as  yet  very  insufficient.     The  great  amount  of  attention  which  is  being 
directed  by  Chemical  Pathologists  to  the  subject,  however,  will  doubtless  ere 
long  produce  some  important  results. — Among  the  most  frequent  causes  of  de- 
pravation in  the  character  of  this  fluid,  we  must  undoubtedly  rank  the  retention, 
in  the  Circulating  current,  of  matters  which  ought  to  be  removed  by  the  Ex- 
creting processes.     We  shall  hereafter  see,  that  a  total  interruption  to  the  ex- 
cretion of  Carbonic  Acid  by  the  lungs,  will  occasion  death  in  the  course  of  a 
very  few  minutes ;  and  even  when  only  a  slight  impediment  is  oifered  it,  so  that 
the  quantity  of  carbonic  acid  always  contained  in  arterial  blood  is  augmented 
to  but  a  small  degree,  a  feeling  of  discomfort  and  oppression,  increasing  with 
the  duration  of  the  interruption,  is  speedily  produced.    The  results  of  the  reten- 
tion of  the  materials  of  the  Biliary  and  Urinary  excretions  will  be  hereafter 
considered  (CHAP,  xu.);  and  at  present  it  will  be  only  remarked  that  such 
retention  is  a  most  fertile  source  of  slight  disorders  of  the  system,  that  it  is 
largely  concerned  in  producing  many  severe  diseases,  and  that,  if  complete,  it 
will  most  certainly  and  rapidly  bring  about  a  fatal  result. — The  most  remarka- 
ble cases  of  depravation  of  the  Blood,  by  the  introduction  of  matters  from 
without,  are  those  in  which  these  substances  act  as  ferments,  exciting  such 
Chemical  changes  in  the  constitution  of  the  fluid  that  its  whole  character  is 
speedily  changed,  and  its  vital  properties  are  altogether  destroyed.    Of  such  an 
occurrence,  we  have  characteristic  examples  in  the  severe  forms  of  Typhoid 
fever  commonly  termed  malignant ;   in  Plague,  Glanders,  Pustule   Maligne, 
and  several  other  diseases ;  in  some  of  which  we  can  trace  the  direct  introduction 
of  the  poison  into  the  blood,  whilst  in  others  we  must  infer  (from  the  similarity 
of  result)  that  it  has  been  introduced  through  some  obscure  channel,  probably 
the  lungs.     The  evidence  which  we  possess  of  the  "  intoxication"  of  the  Blood, 
in  these  and  other  cases,  derived  from  the  perversion  of  the  nutritive  operations 
which  it  induces,  will  be  considered  in  the  next  Section. 

3.    Of  the  Vital  Properties  of  the  Blood,  and  its  Relations  to  the  Living 

Organism. 

179.  It  cannot  be  doubted  that  the  perfect  and  regular  performance  of  the 
various  actions  to  which  the  Blood  is  subservient,  is  dependent  upon  the  admix- 
ture of  its  principal  components  in  their  due  proportions,  and  upon  its  freedom 
from  deleterious  matters,  whether  formed  within  the  system,  or  introduced  into 
the  circulating  current  from  without.     And  it  is  not  difficult  to  see  how  any 
considerable  alteration  which  affects  its  physical  conditions  merely,  may  thereby 
produce  a  most  serious  disturbance  in  the  regularity  of  the  circulation,  and  in 
the  functions  to  which  it  ministers.     Thus  it  has  been  shown,  by  the  experi- 
ments of  Poisseuille,  that  a  certain  degree  of  viscidity  is  favorable  to  the  motion 

1  "Etudes  Chimiques  sur  le  Sang,"  p.  106. 


192  OF   THE   BLOOD. 

of  liquids  through  capillary  tubes ;  a  thin  solution  of  sugar  or  gum  being  found 
to  traverse  them  more  readily  than  pure  water  will  do.  Hence  any  serious 
alteration  in  the  proportion  of  the  organic  and  saline  compounds  dissolved  in 
the  liquor  sanguinis,  and  especially  in  that  of  the  fibrin  (on  which  the  viscidity 
of  the  blood  appears  chiefly  to  depend),  might  be  expected  to  produce  obstruc- 
tion in  the  capillary  circulation,  and  to  favor  transudation  of  the  fluid  portion 
of  the  blood;  and  the  numerous  experiments  of  Magendie1  seem  to  favor  this 
view,  although  they  are  far  from  manifesting  that  character  for  accuracy  and 
discrimination,  which  would  be  required  to  afford  an  authoritative  sanction  to  it. 
A  much  more  determinate  influence,  however,  must  be  exerted  upon  the  red 
corpuscles,  by  any  cause  which  seriously  affects  the  specific  gravity  of  the  liquor 
sanguinis  (§  139) ;  and  the  perfect  elaboration  of  the  albuminous  constituent 
of  the  serum  has  been  shown  to  be  requisite,  to  prevent  it  from  copiously  trans- 
uding the  membranous  walls  of  the  vessels  which  it  traverses  (§  167). — These 
and  other  physical  and  chemical  relations  of  the  Blood,  however,  are  quite  sub- 
ordinate to  its  Vital  reactions;  and  it  is  into  them  that  we  have  now  to  inquire. 
180.  There  are  only  two  constituents  of  the  circulating  Blood,  which  can  be 
considered  as  being  themselves  endowed  with  vital  properties ;  these  are,  the 
Fibrin  and  the  Corpuscles.  The  remainder  of  its  components  can  scarcely  be 
looked  upon  in  any  other  light  than  as  chemical  compounds,  which  are  to  be 
rendered  subservient  to  the  nutritive  and  other  operations  of  the  living  tissues 
in  virtue  of  their  vitality,  or  which  have  already  discharged  their  duty  in  the 
system.  To  attribute  vital  properties  to  a  substance  which,  like  Fibrin,  is 
usually  in  a  state  of  solution,  has  been  .considered  by  some  Physiologists  as  an 
absurdity ;  but  there  seems  no  adequate  reason  why  liquids,  as  well  as  solids, 
should  not  possess  vital  attributes  ;a  and  it  has  been  already  shown,  that  the 
power  exhibited  by  fibrin,  of  spontaneously  passing  (under  certain  conditions) 
into  an  organized  texture,  however  low  its  type,  cannot  be  legitimately  considered 
in  any  other  light  than  as  a  vital  endowment  (§§  26—29).  That  the  Corpuscles, 
however,  both  Red  and  Colorless,  are  living  cells,  and  that,  like  other  cells, 
they  possess  vital  endowments  peculiar  to  themselves,  is  not  now  questioned  by 
any  one;  and  their  separate  history  forms  no  unimportant  element  in  the  gene- 
ral "  Life  of  the  Blood,"  whilst  it  can  scarcely  be  doubted,  from  the  facts 
already  stated,  that  it  has  a  most  important  relation  to  the  Life  of  the  body 
generally. — Before  proceeding,  however,  to  inquire  into  the  nature  of  this  rela- 
tion, our  attention  may  be  advantageously  directed  to  that  remarkable  change 
in  the  state  of  the  blood  when  withdrawn  from  the  vessels  of  the  living  body, 
which  is  commonly  known  as  its  "coagulation."  This  term,  however,  as  applied 
to  the  blood  en  masse,  is  quite  inappropriate;  since,  as  we  shall  presently  see, 
the  coagulation  essentially  consists  in  the  passage  of  the  fibrin  alone  from  the 
soluble  to  the  solidified  state ;  and  this  component  scarcely  forms  more  than  one 
hundredth  part  of  the  whole  solid  matter  of  the  circulating  fluid.  All  the 
phenomena  attendant  upon  this  process,  and  the  conditions  by  which  it  is  influ- 
enced, have  been  made  the  subject  of  very  careful  study,  both  by  Chemists 
and  Physiologists ;  but  it  must  be  admitted  that  they  throw  very  little  light 

1  "Le9ons  sur  les  Phenomenes  Physiques  de  la  Vie." 

2  If,  as  the  recent  observations  of  Mr.  Newport  ("Phil.  Trans."  1851,  p.  241)  appear 
to  show,  the  spermatozoa  in  contact  with  the  ovum  undergo  "diffluerice"  preparatory  to 
the  exertion  of  their  fertilizing  power,  we  have  a  most  remarkable  example  of  the  pos- 
session, by  a  liquid,  of  endowments  which  must  be  considered  as  more  purely  vital  than 
those  of  the  spermatozoa  themselves ;  for  the  latter,  so  long-  as  they  retain  their  organic 
form,  manifest  their  vitality  in  no  other  way  than  by  the  performance  of  rhythmical  move- 
ments.    It  would  seem,  in  fact,  as  if  the  fertilizing  material,  prepared  by  the  agency  of 
the  seminal  cells,  had  been  temporarily  cast  into  the  solid  form,  for  the  sake  of  enabling 
it  to  find  its  way,  by  spontaneous  movement,  to  the  ovum  it  is  destined  to  impregnate. 


ITS  VITAL  PROPERTIES,  AND  RELATIONS  TO  LIVING  ORGANISM.      193 

upon  the  vital  relations  of  the  Blood  to  the  Organism  at  large,  these  being  only 
sustained  whilst  it  is  circulating  in  the  fluid  state,  and  being  interfered  with  by 
anything  that  favors  its  passage  into  the  form  which  it  assumes  when  withdrawn 
from  the  body. 

181.  The  Coagulation  of  the  Blood,  then,  consists  in  the 'new  arrangement  of 
its  constituents,  which  takes  place  when  it  is  drawn  from  the  vessels  and  is  left 
to  itself,  or  when  the  body  itself  dies  (§  138).  This  new  arrangement  essen- 
tially depends  upon  the  passage  of  the  Fibrin  from  the  soluble  to  the  insoluble 
state,  in  which  it  forms,  not  an  amorphous  coagulum,  but  a  network  of  fibres 
more  or  less  definitely  marked  out  (§§  26-28) ;  in  the  meshes  of  which  network 
are  included  the  Red  corpuscles,  usually  grouped  together  in  columnar  masses, 
resembling  piles  of  money.  The  Crassamentum  or  Clot  thus  formed  becomes 
dense,  in  proportion  to  the  amount  of  Fibrin  which  it  contains,  and  to  the 
degree  of  its  elaboration ;  and  it  undergoes  a  gradual  contraction,  by  which  the 
Albuminous,  Saline,  and  Extractive  matters,  still  dissolved  in  the  water,  are  more 
or  less  completely  expelled  from  it,  constituting  the  Serum.  This  separation 
will  not  occur,  however,  if  the  coagulation  take  place  in  a  shallow  vessel ;  nor 
if  the  amount  of  Fibrin  should  be  small,  or  its  vitality  low.  A  homogeneous 
mass,  deficient  in  firmness,  presents  itself  under  such  circumstances ;  though  the 
solid  part  of  this  may  pass  into  a  state  of  more  complete  condensation,  after  the 
lapse  of  a  certain  time. — That  the  coagulation  is  due  to  the  Fibrin,  and  that  the 
Corpuscles  do  not  take  any  active  share  in  the  process,  appears  from  several 
considerations,1  A  microscopical  examination  of  the  Clot  shows  that  it  has  the 
same  texture  with  Fibrin  when  coagulating  by  itself;  the  Corpuscles  clustering 
together  in  the  interspaces  of  the  network,  and  not  being  uniformly  diffused 
through  the  whole  mass.  Their  specific  gravity  being  greater  than  that  of  the 
Fibrin,  they  are  usually  most  abundant  at  the  lower  part  of  the  clot ;  and  the 
upper  surface  is  sometimes  nearly  colorless,  especially  when  the  coagulation  has 
taken  place  slowly  ;  yet  this  upper  part  is  much  firmer  than  the  under,  showing 
that  the  Fibrin  alone  is  the  consolidating  agent.  If,  after  the  complete  subsid- 
ence of  the  Corpuscles,  a  little  of  the  colorless  Liquor  Sanguinis  be  skimmed 
off,  it  will  undergo  complete  coagulation,  forming  a  colorless  clot ;  as  was  long 
ago  shown  by  Hewson.  The  same  fact  may  be  experimentally  demonstrated 
by  the  use  of  methods  which  effect  an  artificial  separation  of  the  Fibrin  from  the 
Corpuscles.  Thus  Miiller  placed  the  blood  of  a  Frog,  diluted  with  water  (or 
still  better,  with  a  very  thin  syrup)  on  a  paper  filter,  of  sufficiently  fine  texture 
to  keep  back  the  Corpuscles ;  and  the  Liquor  Sanguinis,  having  passed  through 
the  filter  completely  unmixed  with  them,  presented  a  distinct  coagulum,  al- 
though, from  the  diluted  state  of  the  fluid,  this  did  not  possess  much  consistency. 
Owing  to  the  more  minute  size  of  the  Blood-disks  of  warm-blooded  animals,  this 
experiment  cannot  be  so  readily  performed  with  their  blood.  So,  again,  if 
fresh-drawn  blood  be  continually  stirred  with  a  stick,  the  Fibrin  will  adhere  to 
it  in  strings  during  its  coagulation ;  and  the  Red  corpuscles  will  be  left  sus- 
pended in  the  serum,  without  the  slightest  tendency  to  coagulate.  Moreover, 
if  a  solution  of  any  salt,  that  has  the  property  of  retarding  the  coagulation  (such 
as  carbonate  of  potash  or  sulphate  of  soda),  be  added  to  the  blood,  the  Corpus- 
cles will  have  time  to  sink  to  the  lower  stratum  of  the  fluid  before  the  clot  is 
formed ;  the  greater  part  of  the  crassamentum  is  then  entirely  colorless,  and  is 
found  by  the  microscope  to  contain  few  or  no  red  particles.  It  will  be  presently 

1  It  is  remarkable  that  this  doctrine,  clearly  established  by  the  older  Physiologists,  and 
especially  by  Hewson,  should  ever  have  been  put  aside,  even  temporarily,  for  the  untenable 
hypothesis  that  the  coagulation  of  the  blood  is  due  to  a  running- together  of  its  red  cor- 
puscles. For  an  admirable  summary  of  the  history  of  opinion  on  this  subject,  see  Mr. 
Gulliver's  Introduction  to  his  edition  of  "  Hewson' s  Works"  (published  by  the  Sydenhaia 
Society). 
13 


194  OF   THE   BLOOD. 

shown,  however,  that  the  difference  of  specific  gravity  is  by  no  means  the  only 
cause  of  the  separation  of  the  Corpuscles  from  the  Liquor  Sanguinis  (§  189). 

182.  That  the  Coagulation  of  the  Blood  is  not,  as  some  have  supposed,  a  proof 
of  its  death,  but  is  rather  an  act  of  vitality,  appears  evident  from  what  has  been 
already  stated  (§  27)  of  the  incipient  organization  which  may  be  detected  even 
in  an  ordinary  clot ;  and  still  more  from  the  fact  that,  if  the  effusion  of  Fibrin 
take  place  upon  a  living  surface,  its  coagulation  is  the  first  act  of  its  conversion 
into  solid  tissues  which  become  constituents  of  the  living  fabric.     It  is  absurd 
to  suppose  that  the  Blood  dies,  in  order  to  assume  a  higher  form.     A  complete 
demonstration  of  the  truth  of  the  Hunterian  doctrine,  that  the   Blood  might 
become   organized,  like  plastic  exudations  of  "  coagulable  lymph,"   has   been 
afforded  by  the  researches  of  Dr.    Zwicky/   on  the  changes  occurring  in  the 
clots  of  blood  which  form  in  bloodvessels,  above  the  points  where  they  have 
been   tied.      He  has  traced  the   successive  stages  of  the  metamorphosis   of 
the  coagulum  into  fibro-cellular  tissue,  and  the  formation  of  vessels  in  its  sub- 
stance ;  the  whole  process  taking  place  exactly  as  in  an  inflammatory  exudation, 
and  the  blood-corpuscles  exerting  no  other  influence  upon  it  than  that  of  slightly 
retarding  it.     Similar  observations  have  been  made  by  Mr.  Paget.3 

183.  Instances  occasionally  present  themselves  in  which  the  Blood  does  not 
coagulate  after  death,  or  coagulates  very  imperfectly.     It  was  affirmed  by  Hun- 
ter3 that  no  coagulation  occurs  in  the  blood  of  animals  hunted  to  death,  or  of 
those  killed  by  lightning,  by  electric  shocks,  or  by  blows  upon  the  epigastrium ; 
and  this  statement  has  been  generally  received  upon  his  authority.     It  is  far, 
however,  from  being  constantly  true ;  for  Mr.  Gulliver  has  collected  numerous 
cases  in  which  coagulation  was  found  to  have  taken  place  in  the  blood  of  ani- 
mals killed  in  each  of  these  modes ;  in  some  of  them,  however,  the  coagulation 
was  very  imperfect.4     It  is  not  improbable  that  some  of  the  instances  of  appa- 
rent absence  of  coagulation  were  really  cases  of  retarded  coagulation  (§  184) ;  and 
Dr.  Polli  goes  so  far  as  to  maintain  that  the  complete  absence  of  coagulating 
power  is  a  phenomenon  which  has  no  real  existence.     He  states  that  he  has 
never  met  with  an  instance  in  which  the  blood,  when  left  to  itself,  and  duly 
protected  from  external  destructive  influences,  did  not  coagulate  before  becom- 
ing putrid ;  and  that  he  has  more  than  once  found  blood  to  coagulate,  which 
had  been  taken  in  a  fluid  state  from  the  vessels  thirty-six  or  forty-eight  hours 
after  death.5     Still  there  seems  no  reasonable  doubt  that  non-coagulation  may 
occur,  when  the  blood  has  been  previously  subjected  to  conditions  which  affect 
the  vitality  of  its  fibrin.    Such  is  often  the  case,  for  example,  when  death  occurs 
from  Asphyxia,  as  by  hanging,  drowning,  or  breathing  of  irrespirable  gases,6 
and  the  same  has  been  observed  in  cases  of  poisoning  by  hydrocyanic  acid,  in 
which  asphyxia  seemed  to  have  been  the  immediate  cause  of  death.     In  certain 
diseased  states,  again,  we  have  seen  that  the  coagulating  power  seems  to  be 
completely  deficient  (§  173). 

184.  The  length  of  time  which  elapses  before  Coagulation,  and  the  degree 
in  which  the  clot  solidifies,  vary  considerably ;  in  general,  they  are  in  the  in- 
verse proportion  to  each  other.     Thus,  if  a  large  quantity  of  blood  be  with- 
drawn from  the  vessels  of  an  animal  at  the  same  time,  or  within  short  intervals, 
the  portions  that  last  flow  coagulate  much  more  rapidly,  but  much  less  firmly, 

1  "Ueber  die  Thrombus  ;"  Zurich,  1846. 

2  See  his  "Lectures  on  the  Processes  of  Repair  and  Reproduction,"  in  the  "Medical 
Gazette"  for  1849,  vol.  xliii.  p.  1066. 

>  "The  Works  of  John  Hunter,"  edited  by  James  F.  Palmer,  vol.  iii.  pp.  34,  114. 
4  See  "Edinb.  Med.  and  Surg.  Journ."  Oct.  1848,  pp.  367,  418;  and  his  edition  of 
"  Hewson's  Works,"  pp.  20,  21. 

6  "Annali  Universal!,"  1845;  and  "Ranking's  Abstract,"  vol.  ii.  p.  337. 

6  See  Dr.  J.  Davy's  "Physiological  and  Anatomical  Researches,"  vol.  ii.  p.  192. 


ITS  VITAL  PROPERTIES,  AND  RELATIONS  TO  LIVING  ORGANISM.      195 

than  those  first  obtained.  In  blood  drawn  during  Inflammatory  states,  again, 
the  coagulation  is  usually  slow,  but  the  clot  is  preternaturally  firm ;  especially 
at  its  upper  part,  where  the  Buffy  coat  (§  189)  or  colorless  stratum  of  fibrin, 
gradually  contracts,  and  produces  the  cup,  which  may  be  generally  considered 
to  indicate  a  high  degree  of  Inflammation.  Although  the  Blood  withdrawn 
from  the  body  coagulates  (except  under  the  peculiar  circumstances  just  stated) 
whether  it  be  kept  at  rest  or  in  motion,  whether  its  temperature  be  high  or  low, 
and  whether  it  be  excluded  from  the  air,  or  be  admitted  to  free  contact  with  the 
atmosphere,  yet  its  coagulation  may  be  accelerated  or  retarded  by  variation  in 
these  conditions. — If  the  blood  be  continually  agitated  in  a  bottle,  its  coagula- 
tion is  delayed,  though  it  will  at  last  take  place  in  shreds  or  insulated  portions; 
but  that  rest  is  not  the  cause  of  its  coagulation  (as  some  have  supposed)  is 
proved  by  the  fact  that,  if  a  portion  of  blood  be  included  between  two  ligatures 
in  a  living  vessel,  it  will  remain  fluid  for  a  considerable  time  ;*  as  it  also  will 
when  effused  into  the  midst  of  living  tissues,  or  kept  in  a  state  of  stagnation 
in  parts  affected  with  inflammation.  Thus  Mr.  Gulliver,  besides  other  instances, 
mentions  a  remarkable  case  witnessed  by  himself,  in  which  a  collection  of  blood 
which  had  been  effused  in  consequence  of  a  bruise  on  the  loins,  was  found  un- 
coagulated  when  let  out  twenty-eight  days  afterwards;  it  measured  five  ounces, 
was  as  liquid  as  blood  just  drawn  from  a  vein,  and  showed  the  normal  characters 
when  examined  microscopically;  and  it  coagulated  in  a  cup  in  less  than  thirty 
minutes  (op.  cit.,  p.  17).  And  Mr.  Paget  mentions  that  he  has  known  the 
blood  remain  fluid  in  the  vessels  of  an  inflamed  part,  though  in  a  state  of  com- 
plete stagnation,  for  as  long  as  three  days.2 — Again,  the  coagulation  is  accelerated 
by  moderate  warmth,  the  natural  heat  of  the  body  from  which  the  blood  is  taken 
appearing  to  be  most  favorable  to  it;  but  the  coagulating  power  appears  to  be 
destroyed  by  a  temperature  of  about  150°,  blood  heated  to  that  point  remaining 
permanently  fluid.  (Gulliver,  op.  cit.,  pp.  4,  5.)  On  the  other  hand,  the  co- 
agulation is  retarded  by  cold ;  but  the  coagulating  power  is  not  destroyed  even 
by  extreme  cold ;  for  if  blood  be  frozen  immediately  that  it  is  drawn,  it  will 
coagulate  on  being  thawed. — Moreover,  it  is  accelerated  by  exposure  to  air,  but 
it  is  not  prevented  by  complete  exclusion  from  it,  as  is  proved  by  its  taking 
place  in  a  vacuum,  or  in  a  shut  sac  within  the  dead  body  :  complete  exclusion 
from  the  air,  however,  retards  the  change ;  as  has  been  shown  by  causing  blood 
to  flow  into  a  vessel  containing  oil,  which  will  form  an  impervious  coating  on  its 
surface,  and  will  occasion  the  coagulation  to  take  place  so  slowly,  that  the  red 
particles  have  time  to  subside,  and  the  upper  stratum  of  the  clot  is  colorless.3 — 
The  effect  of  the  addition  of  strong  solutions  of  neutral  salts  to  fresh  blood,  is 
usually  to  retard,  and  sometimes  even  to  prevent,  its  coagulation ;  and  the  same 
effect  is  produced  by  many  vegetable  substances,  particularly  those  of  the  nar- 
cotic and  sedative  class,  such  as  opium,  belladonna,  aconite,  hyoscyamus,  digi- 
talis, and  tea  or  coffee  in  strong  infusion.4  The  action  of  most  of  the  sub- 
stances, however,  which  preserve  the  fluidity  of  the  blood,  only  continues  during 

1  The  testimony  of  all  experimenters  is  in  accordance  on  this  point,  although  they  differ 
as  to  the  length  of  time  that  elapses  before  coagulation  commences.     Mr.  Gulliver  states 
that  out  of  many  trials  made  by  him,  the  coagulation  commenced  within  two  hours  in  only 
a  few  instances ;  more  commonly,  three,  four,  or  five  hours  elapsed  before  any  clot  was 
formed ;  and  in  one  instance  the  coagulation  was  incomplete  at  the  end  of  twenty-four 
hours.     In  all  these  experiments,  the  blood  coagulated  in  the  course  of  a  few  minutes,  when 
withdrawn  from  the  living  vessel.    See  Mr.  Gulliver's  edition  of  "  Hewson's  Works,"  p.  23. 

2  "Lectures  on  Inflammation,"  in  "Medical  Gazette,"  1850,  vol.  xlv.  p.  971. 

3  Dr.  Babington  in  "  Medico-Chirurgical  Transactions,"  vol.  xvi. 

4  See  Dr.  J.  Davy's  "Anatomical  and  Physiological  Researches,"  vol.  ii.  pp.  101,  102; 
and  Mr.  Prater's  "Experimental  Inquiries  in  Chemical  Physiology,"  pp.  59,  63,  &c.     A 
copious  table  of  the  results  of  their  experiments  is  given  in  Mr.  Ancell's  "Lectures  on  the 
Physiology  and  Pathology  of  the  Blood,"  in  the  "Lancet"  for  Dec.  21,  1839. 


196  OF   THE   BLOOD. 

such  time  as  their  solutions  retain  a  certain  strength ;  for  if  they  be  diluted, 
coagulation  will  then  take  place,  although  in  most  cases  less  perfectly  than  it 
would  have  done  at  first.  There  appears  to  be  no  limit  to  the  time  during 
which  the  coagulation  may  be  thus  postponed ;  thus  Mr.  Gulliver1  mentions 
that  he  has  kept  horse's  blood  fluid  with  nitre  for  fifty-seven  weeks,  and  that  it 
still  readily  coagulated  when  diluted  with  water  (op.  cit.,  p.  12). — It  is  not  so 
difficult,  therefore,  as  it  might  otherwise  seem,  to  give  credit  to  the  statement 
of  Dr.  Polli,  that,  in  a  case  witnessed  by  himself,  complete  coagulation  of  the 
blood  did  not  take  place  until  fifteen  days  after  it  had  been  withdrawn  from  the 
body;  and  that  fifteen  days  more  elapsed  before  putrefaction  commenced  in  it. 
The  upper  four-fifths  of  the  clot  were  colorless,  the  red  corpuscles  occupying 
only  the  lowest  fifth.  It  is  additionally  remarkable,  that  the  patient  (who  was 
suffering  under  acute  pneumonia)  being  bled  very  frequently  during  the  suc- 
ceeding week,  the  blood  gradually  lost  its  indisposition  to  coagulate.3 

185.  It  has  been  maintained  by  some  observers,  that  a  certain  amount  of 
heat  is  liberated  during  coagulation ;  but  this  idea  would  seem  to  have  been 
founded  on  a  fancied  analogy  between  coagulation  and  freezing;  and  it  is  nega- 
tived by  the  careful  observations  of  Hunter,  Schroeder  Van  der  Kolk,  J.  Davy, 
and  Denis.     Again,  it  has  been  asserted  that  the  act  of  coagulation  is  attended 
by  the  extrication  of  a  small  quantity  of  carbonic  acid;  but  there  is  no  suffi- 
cient proof  that  blood  in  coagulating  gives  out  more  carbonic  acid  than  it 
ordinarily  does  by  exposure  to  the  air  (§  163).     Moreover,  it  has  been  shown 
by  the  experiments  of  Sir  H.  Davy3  and  Dr.  J.  Davy,4  that  no  effect  is  produced, 
either  in  accelerating  or  retarding  coagulation,  by  placing  blood  in  an  atmosphere 
of  nitrogen,  nitrous  gas,  nitrous  oxide,  or  carbonic  acid ;  and  it  has  been  found 
that  coagulation  still  takes  place,  even  if  the  blood  be  agitated  with  carbonic 
acid. 

186.  The  vital  condition  of  the  walls  of  the  bloodvessels  appears  to  have  an 
important  influence  upon  the  fluidity  of  the  blood.     Thus  it  has  been  found  by 
Sir  A.  Cooper  and  Mr.  Thackrah,  that  whilst  blood  inclosed  in  a  living  vein  re- 
tained its  fluidity  for  some  time,  blood  similarly  inclosed  in  a  dead  vein,  the 
atmosphere  being  completely  excluded,  coagulated  in  a  quarter  of  an  hour. 
Moreover,  inflammation  of  the  walls  of  the  bloodvessels  (which  is  a  condition 
of  depressed  vitality,  CHAP.  xi.  SECT.  3)  promotes  the  coagulation  of  the  blood 
which  they  contain ;  and  thus  it  is  that  the  trunks  both  of  arteries  and  veins 
frequently  become  choked  up  by  coagula.5     Moreover,  although  there  can  be  no 

1  Mr.  Gulliver  considers  this  fact,  together  with  the  occurrence  of  coagulation  on  the 
thawing  of  blood  which  has  been  frozen  whilst  yet  fluid,  as  conclusive  against  the  vital 
character  of  the  act ;  remarking  that  if  we  believe  the  coagulation  to  be  an  eifect  of  life, 
we  must  admit  that  we  can  freeze  and  pickle  the  life  (op.  cit.,  p.  21).     No  such  admission, 
however,  is  necessary.     We  do  not  freeze  and  pickle  the  life ;  but  we  simply  preserve  the 
vital  properties  of  the  substance  by  preventing  it  from  undergoing  spontaneous  change ; 
thus  doing  the  same  for  the  blood  as  may  be  done  for  seeds,  eggs,  and  even  highly  organ- 
ized bodies,  which  may  be  kept  in  a  state  of  "dormant  vitality"  for  unlimited  periods,  by 
cooling  or  drying  them,  or  by  secluding  them  from  the  atmosphere.     See  "Princ.  of  Phys., 
Gen.  and  Comp.,"  CHAP.  in.  Sect.  4,  Am.  Ed. 

2  "Gazetta  Medica  di  Milano,"  Genn  20,  1844;  cited  in  Mr.  Paget's  "Report"  in  "Brit, 
and  For.  Med.  Rev."  vol.  xix.  p.  252. 

a  "Researches  on  Nitrous  Oxide,"  pp.  380-1. 

4  "Anatomical  and  Physiological  Researches,"  vol.  ii.  p.  71. 

*  It  was  observed  by  Hunter,  and  has  been  frequently  noticed  since,  that  when  amputa- 
tion is  performed  on  account  of  spontaneous  gangrene  of  the  lower  extremities,  there  is 
no  jet  of  blood  from  the  divided  arterial  trunk,  which  is  obstructed  by  coagulum  far  above 
the  line  to  which  the  gangrene  has  extended ;  and  there  is  good  reason  to  regard  the  gan- 
grene as,  in  these  cases,  the  result  of  a  previous  arteritis,  which  has  thus  put  a  stop  to  the 
circulation  through  the  limb.  (For  evidence  in  support  of  this  doctrine,  see  the  "Essai 
sur  les  Gangrenes  spontanees"  of  M.  Fra^ois,  Paris,  1832.)  The  author,  whilst  a  pupil 


ITS  VITAL  PROPERTIES,  AND  RELATIONS  TO  LIVING  ORGANISM.      197 

doubt  that  a  large  proportion  of  the  loose  fibrin ous  masses  found  in  the  heart  and 
large  vessels  after  death  are  the  result  of  post-mortem  coagulation,  yet  there  is 
adequate  evidence,  derived  from  the  symptoms  observed  during  life,  and  from 
the  appearances  presented  by  the  coagula  themselves,  that  the  coagulation  has 
commenced  during  life ;  and  in  all  cases  of  this  kind,  there  has  been  a  marked 
depression  of  vital  power  for  some  time  previous  to  the  final  extinction  of  life. 
Again,  it  was  found  by  Schrreder  Van  der  Kolk,1  that  if  the  substance  of  the 
brain  and  spinal  marrow  be  broken  down,  coagulation  of  the  blood  takes  place 
whilst  it  is  still  moving  within  the  vessels ;  clots  being  found  in  them  even 
within  a  few  minutes  after  the  operation.  Further,  that  the  contact  of  a  dead 
substance  promotes  coagulation,  even  in  the  living  and  actively  moving  blood, 
is  shown  by  the  experiments  of  Mr.  Simon,  who  carried  a  single  thread  (by 
means  of  a  very  fine  needle)  transversely  through  an  adjacent  artery  and  vein 
of  a  dog,  and  left  it  there,  so  that  it  might  cut  the  stream,  for  a  period  of  from 
twelve  to  twenty-four  hours;  the  consequence  of  which  was  that  a  coagulum 
was  formed  upon  the  thread,  more  or  less  completely  obstructing  the  vessel. 
There  was,  however,  a  marked  difference  in  the  coagula  formed  within  the  artery 
and  the  vein  respectively,  which  may  be  attributed  to  the  difference  in  the 
quality  of  the  fibrin  in  the  blood  of  the  two  vessels  (§  164),  or  to  the  differ- 
ence in  the  rate  of  its  motion,  or  to  both  causes  conjointly  ;  for  the  thread  which 
traversed  the  artery  usually  presented  a  "  vegetation"  on  its  surface,  sometimes 
as  large  as  a  grain  of  wheat,  always  of  a  pyramidal  shape,  with  its  base  attached 
to  the  thread,  and  its  apex  down-stream ;  whilst  the  venous  coagulum  was  a 
voluminous  black  clot,  chiefly  collected  on  that  side  of  the  thread  remotest  from 
the  heart.2 

187.  Again,  the  contact  of  dead  animal  matter  with  the  blood  appears  to 
promote  the  coagulation  of  its  fibrin  in  a  very  remarkable  degree  j  occasioning 
coagula  to  form  whilst  it  is  yet  actively  moving  in  the  vessels  of  the  living  body. 
Thus  M.  Dupuy  found  that  the  injection  of  cerebral  substance  into  the  veins  of 
an  animal  occasioned  its  death  almost  as  instantaneously  as  if  prussic  acid  had 
been  administered ;  the  circulation  being  rapidly  brought  to  a  stand  by  the  forma- 
tion of  voluminous  clots  in  the  heart  and  large  vessels.  These  experiments 
were  repeated  and  confirmed  by  M.  de  Blainville.3  The  same  effect  is  produced 

at  the  Middlesex  Hospital  in  1835,  witnessed  a  remarkable  case  of  Phlebitis  (apparently 
brought  on  by  suppressed  menstruation),  in  which  both  femoral  veins  were  successively 
affected,  and  in  which  death  took  place  suddenly  when  the  patient  appeared  to  be  recover- 
ing from  the  attack ;  on  post-mortem  examination,  not  only  the  iliac  trunks,  but  also  the 
vena  cava,  for  some  distance  above  their  junction,  were  found  to  be  completely  obstructed 
by  nearly  colorless  coagula  adherent  to  their  walls ;  so  that  the  wonder  was,  how  any  re- 
turn of  blood  could  have  taken  place  from  the  pelvis  and  lower  extremities.  There  seemed 
no  reason  to  attribute  the  formation  of  these  coagula  to  the  introduction  of  pus  into  the 
venous  circulation. 

1  "Comment,  de  Sanguinis  Coagulatione,"  Groeningen,  1820. 

2  "Lectures  on  General  Pathology,"  p.  48,  Am.  Ed.     Mr.  Simon  applies  this  fact  to 
the  explanation  of  the  "vegetations"  which  so  commonly  present  themselves  upon  the 
valves  of  the  heart,  in  cases  of  rheumatic  endocarditis ;  maintaining  that  they  are  simple 
deposits  from  the  fibrin  of  the  blood,  which  is  unusually  abundant  in  this  condition.     This 
doctrine  can  only  be  substantiated,  however,  by  a  careful  microscopic  examination  of  these 
substances ;  and  if  they  should  be  proved  to  have  the  simple  constitution  which  Mr.  Simon 
imputes  to  them,  the  fact  will  in  no  degree  set  aside  (as  he  seems  to  consider  it  must  do) 
the  existence  of  endocardial  inflammation,  but  will  rather  confirm  it,  since  the  deposition 
of  fibrin  on  those  particular  spots  is  likely  to  be  specially  determined  by  inflammation  of 
the  subjacent  membrane. 

3  "Gazette  Medicale,"  1834,  p.  521.     There  is  no  reason  to  suppose  that  cerebral  sub- 
stance possesses  a  more  special  influence  than  would  be  exerted  by  any  other  tissue  which 
could  be  as  easily  mixed  up  with  the  circulating  current.     It  will  be  remembered  that  the 
presence  of  a  piece  of  flesh,  or  of  the  clot  of  blood,  determines  the  coagulation  of  fibrin 
in  a  solution  from  which  it  would  not  otherwise  have  separated  ($  26). 


198  OP   THE   BLOOD. 

with  still  more  potency  when  the  substance  injected  is  rather  undergoing  degra- 
dation, than  actually  dead ;  for  it  then  seems  to  act  somewhat  after  the  manner 
of  a  ferment,  producing  a  marked  diminution  in  the  vitality  of  the  solids  and 
fluids  with  which  it  may  be  brought  in  contact.  Such  is  pre-eminently  the  case 
with  pus,  as  was  long  since  observed  by  Hunter,  and  as  Mr.  H.  Lee  has  lately 
determined  more  precisely.  It  was  found  by  the  latter,  that  healthy  blood 
received  into  a  cup  containing  some  offensive  pus,  coagulated  in  two  minutes ; 
whilst  another  sample  of  the  same  blood,  received  into  a  clean  vessel  of  similar 
size  and  shape,  required  fifteen  minutes  for  its  complete  coagulation.  When  he 
injected  putrid  pus  into  the  jugular  vein  of  a  living  ass,  coagulation  took  place 
so  instantaneously  as  to  produce  an  immediate  obstruction  to  the  current  of  blood, 
so  that  the  vessel  at  once  acquired  a  cord-like  character;  and  in  this  mode  the 
pus  was  usually  prevented  from  finding  its  way  into  the  general  current  of  the 
circulation.  Whilst  it  thus  remains  circumscribed  by  a  coagulum  of  blood,  the 
pus  so  introduced  seems  to  produce  no  other  constitutional  disturbance  than  is 
attributable  to  the  local  injury ;  but  if  the  circumscription  should  be  incomplete, 
and  the  pus  should  be  carried  into  the  general  circulation,  it  becomes  a  source 
of  extensive  mischief,  determining  the  formation  of  abscesses  in  various  parts,  and 
producing  a  most  depressing  influence  on  the  system  at  large.1  The  effect  of 
certain  animal  poisons  of  a  still  more  potent  nature,  when  introduced  into  the 
current  of  the  circulation  (as  by  the  bite  of  venomous  serpents),  appears  to  be 
like  that  of  a  high  temperature,  the  entire  destruction  of  the  coagulating  power 
of  the  blood,  as  well  as  of  the  vital  endowments  of  the  tissues  generally  (§115). 

188.  The  proportions  of  Serum  and  Clot  which  present  themselves  after 
coagulation  are  liable  to  great  variation,  independently  of  the  amount  of  the 
several  ingredients  characteristic  of  each  ;  for  the  crassamentum  may  include, 
not  only  the  fibrin  and  red  corpuscles,  but  also  a  large  proportion  of  the  serum, 
entangled  as  it  were  in  its  substance.     This  is  particularly  the  case  when  the 
coagulation  is  rapid ;  and  the  clot  then  expels  little  or  none  of  it  by  subsequent 
contraction.     On  the  other  hand,  if  the  coagulation  be  slow,  the  particles  of 
fibrin  usually  seem  to  become  more  completely  aggregated,  the  coagulum  is 
denser  at  first,  and  its  density  is  greatly  increased  by  subsequent  contraction. 
When  a  firm  fresh  clot  is  removed  from  the  fluid  in  which  it  is  immersed,  its 
contraction  is  found  to  go  on  increasing  for  24  or  even  48  hours,  serum  being 
squeezed  out  in  drops  upon  its  surface;  and  in  order,  therefore,  to  form  a 
proper  estimate  of  the  relative  proportions  of  Crassamentum  and  Serum,  the 
former  should  be  cut  into  slices,  and  laid  upon  bibulous  paper,  that  the  latter 
may  be  pressed  from  it  as  completely  as  possible. — According  to  the  experiments 
of  Mr.  Thackrah,2  coagulation  takes  place  sooner  in  metallic  vessels  than  in 
those  of  glass  or  earthenware,  and  the  quantity  of  serum  separated  is  much  less; 
in  one  instance,  the  proportion  of  serum  to  clot  was  as  10  to  24  \  when  the  blood 
coagulated  in  a  glass  vessel ;  whilst  a  portion  of  the  same  blood,  coagulating  in 
a  pewter  vessel,  gave  only  10  of  serum  to  175  of  clot.     The  specific  gravity  of 
Blood  is  no  measure  of  its  coagulating  power ;  for  a  high  specific  gravity  may 
be  due  to  an  excess  in  the  amount  of  corpuscles,  which  form  the  heaviest  part 
of  the  blood ;  and  may  be  accompanied  by  a  diminution  in  the  quantity  of  fibrin, 
which  is  the  coagulating  element. 

189.  The  surface  of  the  Crassamentum  not  unfrequently  exhibits,  in  certain 
disordered  conditions  of  the  blood,  a  layer  that  is  nearly  free  from  color  ;  and 
this  is  known  as  the  Buffy  Coat.     The  presence  of  this  has  been  frequently 
regarded  as  a  sign  of  the  existence  of  Inflammation,  indicating  an  undue  pre- 

1  See  Mr.  H.  Lee's  excellent  Treatise  "  On  the  Origin  of  Inflammation  of  the  Veins,  and 
on  Purulent  Deposits." 

3  "Inquiry  into  the  Nature  and  Properties  of  the  Blood,"  2d  edit.,  p.  66. 


ITS  VITAL  PROPERTIES^  AND  RELATIONS  TO  LIVING  ORGANISM.     199 


Fig.  17. 


dominance  of  fibrin  ;  but  this  idea  is  far  from  being  correct,  since,  as  will  pre- 
sently appear  (§  190),  it  may  result  from  an  opposite  condition  of  the  blood. 
A  similar  colorless  layer  is  usually  observable,  when  the  coagulation  of  the 
blood  has  been  retarded  by  the  addition  of  agents  that  have  the  power  of  delay- 
ing it  (§  184) ;  and  since,  in  inflammatory  states  of  the  system,  the  blood  is 
generally  long  in  coagulating,  it  has  been  supposed  that  the  separation  of  the 
red  particles  from  the  fibrinous  parts  of  the  clot  is  due  to  this  cause  alone.  It 
was  long  since  pointed  out  by  Dr.  Alison,1  however,  that  this  explanation  is  in- 
sufficient, for  the  two  following  reasons :  "1.  The  formation  of  the  bufly  coat, 
though  no  doubt  favored  or  rendered  more  complete  by  slow  coagulation,  is 
often  observed  in  cases  where  the  coagulation  is  more  rapid  than  usual ,  and  the 
coloring  matter  is  usually  observed  to  retire  from  the  surface  of  the  fluid  in  such 
cases,  before  any  coagulation  has  commenced.  2.  The  separation  of  the  fibrin 
from  the  coloring  matter  in  such  cases  takes  place  in  films  of  blood,  so  thin  as 
not  to  admit  of  a  stratum  of  the  one  being  laid  above  the  other ;  they  separate 
from  each  other  laterally,  and  the  films  acquire  a  speckled  or  mottled  appear- 
ance, equally  characteristic  of  the  state  of  the  blood  with  the  bufly  coat  itself/' 
— Now  we  have  already  seen  that  the  red  corpuscles  of  healthy  blood  have  a 
tendency  to  aggregate  together  in  piles  and  masses ;  and  it  has  been  pointed 
out  by  Prof.  H.  Nasse2  and  Mr.  Wharton  Jones,3  that  this  tendency  is  greatly 
augmented  in  inflammatory  blood  (Fig.  17),  so  that  the  corpuscles  run  together 
into  little  clumps  often  visible  to  the 
naked  eye,  and  adhere  to  each  other 
with  considerable  tenacity.  Further,  it 
has  been  shown  by  Mr.  Gulliver4  that 
the  subsidence  of  the  red  corpuscles  is 
more  rapid  in  inflammatory  than  it  is  in 
healthy  blood,  and  that  their  rate  of  sink- 
ing increases  with  their  aggregation  ;  so 
that  whilst  they  sink  about  an  eighth 
of  an  inch  during  the  first  two  or  three 
minutes,  they  sink  through  five  or  six 
times  that  space  in  the  next  interval  of 
the  same  length.  That  the  quickness 
with  which  they  thus  aggregate  in  the 
lower  part  of  the  clot,  does  not  depend 
(in  the  case  of  inflammatory  blood)  upon 
the  mere  facility  with  which  they  sink, 
was  further  determined  by  the  use  of 
means  which  tended  to  diminish  or  in- 
crease their  aggregation ;  thus  it  was 
found  that  the  addition  of  weak  saline 
solutions,  by  which  the  liquor  sanguinis 
is  attenuated,  but  which  dimmish  the 
mutual  attraction  of  the  red  corpuscles, 

partially  or  completely  prevented  the  formation  of  the  bufly  coat,  in  blood  which 
exhibited  it  strongly  when  left  pure,  even  though  its  coagulation  was  consider- 
ably retarded  thereby  j  on  the  other  hand,  the  addition  of  mucilage  with  a  small 
quantity  of  saline  matters,  the  effect  of  which  is  to  promote  the  aggregation  of 
the  corpuscles,  tended  to  develop  the  bufly  coat  by  increasing  the  rate  at  which 

1  "Outlines  of  Physiology,"  3d  edit.,  p.  89. 

2  "Das  Blut,"  cited  in  Henle's  "  Anatomie  G&ierale"  (traduit  par  Jourdan),  p.  468. 

3  "Report  on  Inflammation,"  in  "Brit,  and  For.  Med.  Rev."  vol.  xvii.  p.  567. 

4  See  his  Memoir  "On  the  Buffy  Coat  of  the  Blood,"  in  the  "Edinb.  Med.  and  Surg. 
Journ."  No.  165  ;  and  his  edition  of  "  Hewson's  Works,"  p.  41. 


The  microscopic  appearance  of  a  drop  of  Blood  in 
the  Inflammatory  condition.  The  red  corpuscles  lose 
their  circular  form,  and  adhere  together ;  the  white 
corpuscles  remain  apart,  and  are  often  more  abund- 
ant than  usual. 


200  OF   THE   BLOOD. 

they  sink.  Nowj  as  it  has  been  found  that  liquor  sanguinis  deprived  of  its  cor- 
puscles coagulates  more  slowly  than  unaltered  blood,  it  does  not  seem  improbable, 
as  Mr.  Gulliver  has  remarked,  that  this  separation  of  the  two  components  of 
the  crassamentum,  which  determines  the  formation  of  the  buffy  coat,  is  the 
cause,  rather  than  the  consequence,  of  the  slowness  of  the  coagulation  of  inflam- 
matory blood. — It  is  in  the  buffy  coat  of  inflammatory  blood,  that  we  see  the 
clearest  indications  of  organization  ever  presented  by  the  circulating  fluid.  The 
fibrous  network  is  frequently  extremely  distinct ;  and  it  commonly  includes  a 
large  number  of  colorless  corpuscles  in  its  meshes,  these,  indeed,  being  some- 
times so  numerous,  that  it  is  almost  entirely  composed  of  them.  In  its  Chemi- 
cal Composition,  the  buffy  coat  of  inflammatory  blood  appears  to  be  peculiar ; 
containing  a  larger  or  smaller  amount  of  the  substance,  readily  soluble  in  boil- 
ing water,  which  is  considered  by  Mulder  to  be  the  tritoxide  of  proteine  (§  30). 

190.  When  the  "buff"  arises  from  other  causes,  however,  its  appearance  is 
less  characteristic.  It  appears,  from  the  researches  of  Andral,  that  the  usual 
condition  of  its  production  is  an  increase  in  the  quantity  of  fibrin  in  proportion 
to  the  red  corpuscles,  and  not  a  simple  augmentation  of  fibrin.  This  increase 
may  occur  in  two  ways  :  either  by  an  absolute  increase  in  the  fibrin,  the  amount 
of  the  corpuscles  remaining  unchanged,  or  not  being  augmented  in  the  same 
proportion ; — or  by  a  diminution  of  the  corpuscles;  the  quantity  of  fibrin  re- 
maining the  same,  or  not  diminishing  in  the  same  proportion.  Hence  in  severe 
Chlorosis,  in  which  the  latter  condition  is  strongly  developed  (§  174),  the  buffy 
coat  may  be  as  well  marked  as  in  the  severest  Inflammation.1  Unless  the  com- 
position of  the  blood  be  altered  in  one  of  these  two  ways,  it  is  stated  by  An- 
dral that  the  buffy  coat  is  never  formed ;  the  influence  of  circumstances  which 
favor  it  not  being  sufficient  to  produce  it  when  acting  alone.  The  absence  of 
these  circumstances  may  prevent  it,  however,  when  it  would  otherwise  have  been 
formed ;  thus,  when  the  blood  flows  slowly,  the  "  buff"  is  not  properly  produced; 
because  the  slow  discharge  gives  one  portion  time  to  coagulate  before  another; 
and  only  the  blood  last  drawn  furnishes  the  fibrin  at  the  upper  part  of  the  ves- 
sel. Again,  in  a  deep  narrow  vessel,  the  "  buff"  will  form  much  more  decidedly 
than  in  a  broad  shallow  one ;  because  the  thickness  of  the  fibrinous  crust  will 
be  greater. 

191.  It  appears,  then,  from  the  foregoing  facts,  that  we  must  regard  the  co- 
agulation of  the  blood  as  essentially  dependent  upon  the  vital  properties  of  its 
Fibrin  ;  the  tendency  to  aggregation  which  is  exhibited  by  the  Red  Corpuscles, 
having  no  special  part  in  it,  except  when  that  tendency  is  abnormally  augmented, 

1  The  records  of  Medicine  scarcely  furnish  a  more  notable  example  of  the  pernicious 
influence  of  theories  founded  upon  a  shallow  empiricism,  and  of  the  superiority  of  a 
rational  practice  based  on  a  knowledge  of  the  real  facts  of  the  case,  than  is  afforded  by 
the  contrast  between  the  former  and  the  present  treatment  of  Chlorosis.  Whilst  the  notion 
prevailed  that  the  buify  coat  is  a  sign  of  Inflammation,  and  that  the  most  powerful  remedy 
for  Inflammation  is  loss  of  blood,  patients  already  reduced  to  a  state  of  anaemia,  who  com- 
plained of  pain  in  the  left  hypochondrium,  palpitations,  &c.,  were  bled  over  and  over  again, 
every  withdrawal  of  blood  of  course  seriously  increasing  the  mischief,  by  producing  a  fur- 
ther reduction  in  the  proportion  of  red  corpuscles  ($  162).  The  author  well  remembers 
that,  when  a  pupil  in  the  Bristol  Infirmary  in  the  years  1833-4,  he  was  repeatedly  directed 
by  the  estimable  Senior  Physician  (long  since  dead)  to  draw  eight,  ten,  or  twelve  ounces 
of  blood  from  patients  in  this  condition;  and  that  the  crassamentum,  after  coagulation, 
often  resembled  a  small  island  floating  in  an  ocean  of  serum.  Yet,  because  this  minute 
clot  exhibited  the  buffy  coat,  the  bleeding  was  considered  to  be  "orthodox"  practice,  and 
the  obstinacy  of  the  anaemic  state  was  attributed  to  the  severity  of  the  disease.  If  M. 
Andral  had  made  no  other  contribution  to  Medical  Science  than  the  demonstration  of  the 
real  nature  of  this  condition  of  the  blood,  and  of  the  influence  of  further  withdrawal  of 
that  fluid  in  promoting  it,  he  would  have  rendered  a  most  essential  service  to  the  multi- 
tudes of  females  who  are  unfortunate  enough  to  suffer  from  this  kind  of  deterioration  of 
their  vital  fluid, 


ITS  VITAL  PROPERTIES,  AND  RELATIONS  TO  LIVING  ORGANISM.     201 

and  then  only  influencing  the  relative  situations  of  the  two  components  of  the 
clot.  The  deficiency  in  coagulating  power,  by  which  the  blood  is  sometimes 
marked,  must  be  attributed  to  the  want  of  due  elaboration  in  the  Fibrin  alone, 
or  to  the  destruction  of  its  vital  endowments  by  some  agent  which  has  a  nox- 
ious influence  upon  it ;  of  the  former  condition  we  seem  to  have  an  example  in 
such  a  case  as  that  already  cited  (§  176),  in  which  the  circulating  fluid  consisted 
of  a  very  crude  chyle ;  of  the  latter,  in  those  diseased  states  in  which  we  can 
trace  the  operation  of  a  poison  upon  blood  that  was  previously  healthy,  as  when 
asphyxia  has  occasioned  the  retention  of  carbonic  acid  generated  within  the 
system,  or  when  the  materies  morbi  of  cholera  or  some  malignant  fever  has  been 
introduced  into  the  circulation.  But  it  would  be  by  no  means  fair  to  attribute 
the  noxious  influence  of  such  poisons  solely  to  their  power  of  destroying  the 
coagulability  of  the  blood-fibrin,  for  it  is  obviously  exerted  in  many  other  ways; 
and  it  is  probable  that  the  same  agency  which  kills  the  fibrin  exerts  a  similar 
destructive  power  on  the  vitality  of  the  corpuscles,  and  on  that  of  the  tissues 
through  which  the  poisoned  blood  circulates.  But  whilst  we  attribute  the  co- 
agulating power  of  the  Blood  to  the  vital  endowments  of  the  fibrin,  we  can 
scarcely  fail  to  perceive  that  the  exercise  of  this  power  is  kept  in  check  (so  to 
speak)  by  the  vital  endowments  of  the  living  tissues  with  which  it  is  in  contact. 
For,  as  we  have  seen,  the  main  condition  of  coagulation  is  the  diminution  or 
cessation  of  their  agency,  either  by  the  withdrawal  of  blood  from  the  body,  or 
by  the  death  of  the  organism  enclosing  it,  or  by  the  lowered  vitality  of  the  tis- 
sues through  which  it  moves  (§  186) ;  whilst  mere  stagnation  exerts  but  a 
secondary  influence  upon  it  (§  184).  And  thus  we  seem  entitled  to  say,  that 
the  liquid  condition  of  the  fibrin  is  a  result  of  a  balance  of  forces  between  the 
fibrin  and  the  living  tissues,  those  of  the  former  tending  to  its  solidification, 
whilst  those  of  the  latter  maintain  its  fluidity ;  but  that  if  the  latter  should  be 
deficient,  the  former  come  into  uncontrolled  action,  and  expend  themselves  in 
the  production  of  a  lowly-organized  tissue,  the  higher  vitalization  of  which  de- 
pends upon  subsequent  operations  (§  29).  The  source  of  this  vital  endowment 
of  the  Fibrinous  constituent  of  the  blood  must  be  looked  for  in  the  operations 
to  which  the  crude  albuminous  pabulum  is  subjected,  after  its  first  reception  into 
the  system  '}  and  these  will  hereafter  become  the  subject  of  inquiry. 

192.  Of  the  particular  purposes  which  are  served  by  the  Fibrin  of  the  blood 
in  the  vital  economy  of  the  system  at  large,  it  must  be  confessed  that  we  have 
but  little  positive  knowledge.  The  idea  has  been  entertained  by  many  Physi- 
ologists (including  the  Author  of  this  treatise)  that  the  fibrin  is  that  element 
of  the  blood  which  is  immediately  drawn  upon  in  the  operations  of  nutrition ; 
being  the  intermediate  stage  between  the  crude  albumen  and  the  solid  tissues. 
This  opinion  rested  in  part  upon  the  current  doctrine,  that  fibrin  is  the  consti- 
tuent of  Muscle;  and  in  part  upon  the  assumption,  that,  as  fibrin  is  more  en- 
dowed with  vital  properties  than  any  other  of  the  liquid  components  of  the 
blood,  so  as  to  be  capable  of  passing  by  itself  into  the  condition  of  an  organized 
tissue,  it  must  be  the  one  most  readily  appropriated  by  the  various  parts  of  the 
solid  fabric,  as  the  material  for  their  growth  and  development.  Various  con- 
siderations have  of  late  been  adduced,  however,  which  tend  to  shake  this  belief. 
It  has  been  shown  that  so  far  from  there  being  any  evidence  of  the  identity  of 
the  fibrin  of  blood  and  the  substance  of  muscle,  the  evidence  is  precisely  the 
other  way  (§  25).  Again,  we  have  seen  that  there  are  both  structural  and 
chemical  indications,  that  fibrin  is  in  a  state  of  transition  rather  towards  the 
fibro-gelatinous  textures,  than  towards  those  of  the  cellulo-albuminous  type; 
for  the  fibrous  network  which  is  formed  by  its  coagulation  bears  a  greater  resem- 
blance to  the  white  fibrous  tissue  (§  220),  than  to  any  other  texture  of  the  body; 
whilst  the  points  in  which  the  chemical  properties  of  fibrin  differ  from  those  of 
albumen  are  such  as  manifest  a  relationship  to  gelatin  (§§  25 — 30).  We  seem 


202  OF   THE   BLOOD. 

justified  in  regarding  it,  then,  as  the  special  pabulum  of  those  connective  tissues, 
whose  physical  offices  in  the  economy  are  so  important,  whilst  their  vital  endow- 
ments are  so  low  (CHAP.  v.  SECT.  1) ;  and  as  serving,  by  its  own  formative 
power,  for  the  generation  of  these  tissues,  wherever  and  whenever  there  may  be 
a  demand  for  them.  On  the  other  hand,  there  is  a  complete  absence  of  evidence, 
that  the  fibrin  of  the  blood  serves  any  special  purpose  in  the  nutrition  of  the 
cellulo-albuminous  tissues ;  and  there  are  various  negative  indications  that  their 
generation  and  development  do  not  depend  upon  its  presence.  For,  in  the  first 
place,  there  is  evidence  that  a  fluid  destitute  of  coagulating  power  may  serve 
the  general  purposes  of  nutrition ;  this  being  furnished,  not  merely  by  such 
cases  as  that  just  alluded  to  (§  176),  in  which  the  circulating  fluid  was  entirely 
deficient  in  fibrin,  apparently  from  defective  elaboration ;  but  also  by  the  results 
of  experiments  on  the  introduction  of  defibrinated  blood  into  the  vessels  of 
animals  which  had  been  reduced  to  syncope  by  the  withdrawal  of  blood,  it  hav- 
ing been  found,  by  Dieffenbach1  and  Bischoff,3  that  this  operation  immediately 
restored  the  heart's  action,  and,  with  it,  the  general  train  of  vital  operations. 
Further,  although  we  are  not  justified  in  positively  affirming  that  the  fluid  which 
transudes  the  walls  of  the  capillary  bloodvessels,  for  the  nutrition  of  the  tissues 
which  they  supply,  is  albuminous  rather  than  fibrinous,  yet  there  seems  a  strong 
probability  that  such  is  the  case  j  all  non-inflammatory  exudations  being  albumi- 
nous, unless  produced  by  an  excess  of  pressure  (§  227) ;  and  the  fluid  of  the 
lymphatics,  which  is  probably  the  re-collected  surplus  of  that  which  has  thus 
escaped,  being  so  slightly  coagulable,  that  we  may  fairly  regard  the  presence  of 
fibrin  in  it  as  the  result  of  the  elaboration  which  it  has  undergone  during  its 
passage  through  the  absorbent  system.  Moreover,  the  formation  of  the  Vege- 
table cell  takes  place  at  the  expense  of  an  albuminous  fluid,  there  being  no 
element  in  the  juices  of  the  Plant  analogous  to  the  fibrin  of  the  blood ;  and 
although  the  endowments  of  certain  parts  of  Plants  are  so  peculiar  (§  125),  as 
to  prevent  any  such  argument  from  possessing  much  weight,  yet  when  it  is  con- 
sidered that  the  great  mass  of  the  Vegetable  fabric  grows  (like  that  of  Animals) 
at  the  expense  of  nutriment  already  prepared  for  it,  and  that  the  composition  of 
the  Vegetable  cell  is  essentially  the  same  as  that  of  the  Animal  cell  (§  99),  the 
fact  of  the  entire  absence  of  any  substance  at  all  resembling  fibrin  in  the  vege- 
table juices,  and  the  corresponding  deficiency  of  fibre-gelatinous  tissues  in  their 
solid  fabric,  may  be  adduced  in  confirmation  of  the  views  here  advanced. 

193.  Even  if,  however,  we  thus  limit  the  value  of  Fibrin,  as  regards  the 
ordinary  nutritive  processes,  to  the  maintenance  of  the  gelatigenous  tissues,  we 
still  have  to  consider  it  as  a  most  important  component  of  the  blood,  and  as 
altogether  different,  in  its  relations  to  the  living  body,  from  those  products  of 
disintegration  which  are  destined  to  excretion  (§  29,  note}.  For,  putting  aside 
its  presumed  importance  in  maintaining  that  physical  condition  of  the  blood 
which  is  most  favourable  to  its  free  movement  through  the  vessels,  and  to  its 
due  retention  within  their  walls  (§  179),  we  find  that  it  is  entirely  on  the 
coagulating  powers  of  the  blood  that  the  cessation  of  hemorrhage  even  from 
the  most  trifling  injuries  is  dependent ;  that  the  limitation  of  purulent  effusions 
by  the  consolidation  of  the  surrounding  tissue,  and  the  safe  separation  of  gan- 
grenous parts,  can  only  take  place  in  virtue  of  the  same  property ;  and  that  the 
adhesion  of  incised  wounds,  still  more  the  filling  up  of  breaches  of  substance, 
require  as  their  first  condition  that  either  the  blood,  or  matter  exuded  from  it, 
should  be  able  to  assume  the  state  of  fibrous  tissue.  The  results  of  deficiency 
of  coagulating  power  in  the  blood  are  fearfully  seen  in  that  continued  and 
uncontrollable  flow  which  takes  place  in  Purpura,  the  blood  not  being  able  to 
form  a  clot  sufficient  to  fill  up  even  the  wound  made  by  the  scratch  of  a  pin ; 

»  "Die  Transfusion  des  Blutes,"  Berlin,  1828.  2  "Muller's  Archiv.,"  1835. 


ITS  VITAL  PROPERTIES,  AND  RELATIONS  TO  LIVING  ORGANISM.     203 

in  the  want  of  circumscription  of  collections  of  pus  within  an  abscess,  allowing 
its  infiltration  through  tissues  that  were  previously  healthy,  and  thus  occasion- 
ing a  wide-spread  destruction  of  organized  texture,  which  is  characteristic  of 
certain  forms  of  inflammation  (this  result  being  usually  attributable  either  to 
the  previously  unhealthy  condition  of  the  system,  or  to  the  introduction  of  some 
specific  poison  into  the  blood) ;  in  the  want  of  a  corresponding  limitation  be- 
tween the  living  and  the  dead  parts  in  gangrene,  so  that  hemorrhage  takes  place 
on  the  separation  of  the  slough,  the  vessels  not  having  been  previously  obstructed 
by  coagula;  and  in  the  entire  absence  of  any  effort,  either  by  simple  adhesion, 
or  by  the  formation  of  connective  tissue,  whereby  the  sides  of  open  wounds 
may  be  kept  together,  and  dissevered  parts  brought  again  into  connection.  (See 
CHAP.  xi.  SECT.  2.) — On  the  other  hand,  we  see  the  consequences  of  excess  of 
the  proportion  of  fibrin,  and  of  that  increased  plasticity  (or  tendency  to  fibril- 
late)  which  usually  accompanies  its  augmentation,  in  the  tendency  to  form  those 
plastic  effusions  which  are  characteristic  of  the  Inflammatory  state,  and  which, 
if  poured  out  upon  serous  or  mucous  surfaces,  constitute  "  false  membranes" 
and  "  adhesions,"  or,  if  infiltrated  into  the  substance  of  living  tissues,  occasion 
their  consolidation.  This  increased  plasticity  of  the  blood,  however,  may  fre- 
quently be  regarded  in  the  light  of  an  "  effort  of  Nature,"  to  antagonize  the 
evil  consequences  of  that  depression  or  positive  destruction  of  the  vitality  of 
the  solid  tissues  which  seems  to  form  an  essential  part  of  the  inflammatory 
condition ;  and  thus  it  is  that,  whilst  the  central  part  of  a  mass  of  tissue,  in 
which  the  inflammation  has  been  most  intense,  suffers  complete  death,  and  is 
carried  away  in  the  suppurative  process,  the  peripheral  part,  in  which  the  vio- 
lence of  the  inflammation  has  been  less,  becomes  infiltrated  with  plastic  matter 
poured  out  from  the  blood,  and  forms  the  solid  and  impermeable  wall  of  the 
abscess.  (See  CHAP.  xi.  SECT.  3.) 

194.  Turning  now  to  the  Corpuscles  of  the  Blood,  we  have  to  inquire  into  their 
special  functions,  and  into  the  nature  of  their  participation  in  the  vital  opera- 
tions of  the  system  at  large.  Here,  also,  we  are  obliged  to  rely  upon  evidence 
of  a  far  less  satisfactory  nature  than  could  be  desired;  and  at  whatever  con- 
clusions we  may  arrive,  we  must  hold  them  as  probable  only,  and  as  liable  to  be 
modified  by  further  inquiry.  In  the  first  place,  upon  looking  to  the  chemical 
constitution  of  the  Red  Corpuscles,  we  have  seen  that  it  possesses  a  remarkable 
correspondence  with  that  of  Muscle,  in  the  proportion  of  the  potash-salts  which 
they  contain ;  in  this  respect  differing  in  a  very  marked  manner  from  the  liquor 
sanguinis.  So,  again,  it  exhibits  a  like  correspondence  with  that  of  the  Nerve- 
substance,  in  the  quantity  of  phosphorized  fat  which  it  includes  (§  142).  Again, 
the  peculiar  color  which  the  vesicular  nervous  matter  and  the  muscular  substance 
of  warm-blooded  animals  exhibit,  although  doubtless  attributable  in  part  to  the 
actual  presence  of  red  blood  in  these  tissues,  yet  partly  depends  upon  a  pigment- 
ary matter  in  their  own  substance,  which  seems  closely  to  resemble  haematin 
(§  31).  Thus,  then,  from  the  relative  composition  of  the  Red  corpuscles  and 
of  the  Muscular  and  Nervous  tissues,  there  appears  to  be  much  reason  for  re- 
garding the  former  as  destined  to  prepare  or  elaborate  materials  which  are  to  be 
subservient  to  the  nutrition  of  the  latter.  Again,  we  have  seen  that,  although 
the  difference  in  the  color  of  the  red  corpuscles  of  arterial  and  venous  blood 
cannot  now  be  considered  (as  it  formerly  was)  to  be  an  indication  of  chemical 
change  in  their  contents — effected,  on  the  one  hand,  by  the  agency  of  carbonic 
acid,  and,  on  the  other,  by  that  of  oxygen — yet  there  still  appears  reason  to 
regard  these  corpuscles  as  having  more  power  of  absorbing  those  gases  than  is 
possessed  by  any  other  constituent  of  the  blood  (§  142).  Hence  we  may  look 
upon  them  as  specially  subservient  to  the  vital  activity  of  the  nervo-muscular 
apparatus ;  since  it  is  one  of  the  most  important  conditions  of  that  activity,  that 
these  tissues  shall  be  supplied  with  duly  oxygenated  blood,  and  that  the  car- 


204  or  THE  BLOOD. 

bonic  acid  which  is  one  of  the  products  of  their  disintegration  shall  be  conveyed 
away.  And  this  view  is  in  complete  harmony  with  the  fact  that  the  proportion 
of  Red  corpuscles  in  the  blood  bears  a  close  relation  to  the  amount  of  Respira- 
tory power  (as  shown  in  the  quantity  of  carbonic  acid  set  free,  and  in  the 
amount  of  heat  generated)  in  different  classes  of  Vertebrata;  both  being  great- 
est in  birds,  nearly  as  great  in  Mammals,  very  low  in  most  Reptiles,  and  vary- 
ing considerably  among  Fishes.1  Again,  we  observe  that  among  Carnivorous 
Mammalia,  the  proportion  of  red  corpuscles  is  considerably  greater  than  it  is 
among  the  Herbivorous  tribes,  whose  nervo-muscular  energy  is  (upon  the  whole) 
so  greatly  inferior;  and  it  is  in  the  condition  of  greatest  animal  vigor,  in  the 
Human  system,  that  we  find  their  amount  the  greatest,  whilst  the  reduction  of 
that  vigor  by  chronic  disease  of  any  description  seems  invariably  attended  with 
a  more  marked  diminution  in  this  constituent  of  the  blood  than  in  any  other. 
And  in  those  Anaemic  states  of  the  system,  in  which  the  proportion  of  red  cor- 
puscles is  reduced  to  an  extremely  low  point  (§  174),  we  invariably  find  that  the 
animal  powers  are  correspondingly  depressed ;  the  capacity  for  sustained  exer- 
tion, either  of  the  mental  faculties,  or  of  the  motor  apparatus,  being  almost 
destroyed,  although  both  the  nervous  and  muscular  systems  are  very  easily  ex- 
cited to  feeble  action.  However  difficult  it  may  seem  to  explain,  on  this  view, 
the  persistence  of  any  degree  of  nervo-muscular  power,  in  such  cases  as  that 
already  referred  to,  in  which  the  Red  corpuscles  appeared  to  be  entirely  defi- 
cient (§  176),  the  same  difficulty  attends  any  attempt  to  assign  a  use  for  them 
which  shall  be  in  accordance  with  their  well-marked  importance  as  constituents 
of  the  Blood.  And  we  may  suppose  that,  in  such  cases,  the  Colorless  corpuscles, 
although  discharging  their  duty  less  perfectly,  might  to  a  certain  extent  perform 
it,  as  they  seem  to  do  among  the  Invertebrata. 

195.  The  difficulty 'of  precisely  determining  the  functions  of  the  Red  cor- 
puscles is  even  surpassed  by  that  of  assigning  the  probable  duty  of  the  Color- 
less. The  considerations  already  adduced  appear  to  show  that  the  Colorless 
corpuscles  are  to  be  considered  as  cells  of  a  lower  grade  than  the  Red;  since 
they  represent  them  among  Invertebrated  animals,  and  also  in  the  incipient 
blood  of  Vertebrata;  and  also,  because  cells  resembling  the  former  (if  not  the 
very  same)  pass  on  to  develop  themselves  into  the  latter  (§  155).  Still  we 
find  that  this  final  change  does  not  occur  among  the  Invertebrata ;  and  it  is 
obvious,  therefore,  that  even  in  their  colorless  state  the  corpuscles  have  a 
function  to  discharge  in  the  vital  economy.  Little  light  has  yet  been  thrown 
upon  this  subject  by  inquiry  into  the  Chemical  composition  of  the  blood-cor- 
puscles of  the  lower  animals ;  and  no  means  have  yet  been  devised  for  obtain- 
ing the  colorless  corpuscles  of  the  higher  in  a  separate  state,  for  the  purpose  of 
determining  this.  A  minute  sample  of  the  blood-corpuscles  of  a  Crab,  however, 
examined  by  Prof.  Graham,  has  been  found  by  him  to  contain  "a  sensible  quan- 
tity of  iron,  the  proportion  being  perhaps  as  large  as  in  red  corpuscles/'3  Thus, 
then,  we  have  evidence  that  the  difference  of  hue  between  the  two  sets  of  Cor- 
puscles does  not  involve  any  considerable  difference  in  the  proportion  of  one  of 

1  "Princ.  of  Phys.,  Gen.  and  Comp.,"  $  619,  Am.  Ed.     Among  invertebrated  animals, 
as  a  general  rule,   the  degree   of  nervo-muscular  energy  that  can   be    put  forth,  the 
quantity  of  carbonic  acid  produced  in  respiration,  and  the  amount  of  heat  generated  in 
the  body,  are  alike  at  a  low  standard ;  and  the  fluid  constituents  of  the  blood,  with  the 
colorless  corpuscles  that  float  in  it,  would  seem  to  convey  oxygen  to  the  tissues,  and  car- 
bonic acid  to  the  respiratory  organs,  with  sufficient  facility.     In  Insects,  however,  the 
case  is  different;  the  nervo-muscular  activity,  capacity  of  respiration,  and  heat-producing 
power  being  all  extraordinarily  high.     Their  want  of  red  corpuscles  would  here  seem  to 
be  compensated,  so  far  as  the  respiratory  process  is  concerned,  by  the  introduction  of  air 
through  the  tracheal  apparatus,  into  the  tissues  themselves.     ("Princ.  of  Phys.,  Gen. 
and  Comp.,"  \  620,  Am.  Ed.} 

2  "Philosophical  Transactions,"  1846,  p.  105. 


ITS  VITAL  PROPERTIES,  AND  RELATIONS  TO  LIVING  ORGANISM.     205 

the  most  characteristic  elements  of  the  Red ;  and  if  it  be  admitted  that  they 
are  both  to  be  looked  upon  as  having  the  same  origin,  and  as  differing  only  in 
their  stage  of  development,  it  is  manifest  that  no  other  difference  can  fairly  be 
expected  to  exist  in  their  contents  than  that  which  is  marked  by  the  formation  of 
the  coloring  matter,  as  the  final  effort  of  their  transforming  power.  This  pro- 
duct, as  we  have  seen  (§  142)  constitutes  but  about  one-twentieth  of  the  whole 
contents  of  the  Red  corpuscles. — The  following  observation  by  Mr.  Newport 
seems  to  indicate  that  the  corpuscles  of  the  blood  of  Insects  (some  of  them  in 
the  condition  of  "  granule-cells,"  others  in  that  of  "  nucleated  colorless  cells," 
§  147)  have  an  important  function  to  perform  in  the  elaboration  of  nutrient 
material.  The  "  oat-shaped"  corpuscles  (the  "  granule-cells"  of  Mr.  Wharton 
Jones)  are  found,  in  the  Larva,  to  be  most  numerous  at  the  period  immediately 
preceding  each  change  of  skin ;  at  which  time  the  blood  is  extremely  coagulable, 
and  evidently  possesses  the  greatest  formative  power.  The  smallest  number  are 
met  with  soon  after  the  change  of  skin;  when  the  nutrient  matter  of  the 
blood  has  been  exhausted  in  the  production  of  new  epidermic  tissue.  In  the 
Pupa  state,  the  greatest  number  are  found  at  about  the  third  or  fourth  day  sub- 
sequent to  the  change ;  when  preparations  appear  to  be  most  actively  going  on 
for  the  development  of  the  new  parts  that  are  to  appear  in  the  perfect  Insect. 
After  this,  there  is  a  gradual  diminution ;  the  plastic  element  being  progress- 
ively withdrawn  by  the  formative  processes ;  until,  in  the  perfect  insect,  very 
few  remain.  When  the  wings  are  being  expanded,  however,  and  are  still  soft, 
a  few  oat-shaped  corpuscles  circulate  through  their  vessels ;  but,  as  the  wings 
become  consolidated,  these  corpuscles  appear  to  be  arrested  and  to  break  down 
in  the  circulating  passages ;  supplying,  as  Mr.  N.  thinks,  the  nutrient  material 
for  the  completion  of  these  structures,  which  subsequently  undergo  no  change.1 
The  blood  also  contains  nucleated  cells,  the  proportion  of  which  seems  to  in- 
crease in  the  Imago  state,  whilst  that  of  the  "  granule-cells"  diminishes. 

196.  That  condition  of  the  corpuscular  element  of  the  blood  which  is  normal 
in  the  Insect  must  be  considered  as  decidedly  abnormal  in  the  Vertebrated 
animal,  in  which  the  circulating  fluid  goes  on  to  a  higher  phase  of  development; 
and  the  excess  of  Colorless  corpuscles  in  the  latter  seems  always  to  be  associated 
(save  in  the  early  part  of  life)  with  an  imperfect  performance  of  their  nutritive 
operations.  Thus,  according  to  the  observations  of  Mr.  Paget,  they  are  espe- 
cially abundant  in  the  blood  of  frogs  that  are  young,  sickly,  or  ill-fed ;  and 
whilst  in  the  first  of  these  cases,  their  large  number  seems  to  depend  upon  rapid 
increase,  so  that  new  red  corpuscles  may  be  generated  in  adaptation  to  quick  growth, 
in  the  two  latter  their  accumulation  seems  rather  to  be  attributable  to  a  retarda- 
tion of  development  through  disease  or  defective  nutriment,  so  that,  although 
their  production  is  not  hindered,  their  normal  metamorphosis  does  not  take 
place.  So,  as  regards  the  human  subject,  Mr.  Paget  confirms  the  statement  of 
Mr.  Wharton  Jones  and  Prof.  J.  H.  Bennett,  that  the  increased  proportion  of 
Colorless  corpuscles  which  has  been  regarded  by  some  observers  (especially  by 
Mr.  Addison  and  Dr.  C.  J.  B.  Williams)  as  characteristic  of  inflammatory 
blood,  and  particularly  of  that  which  is  drawn  from  an  inflamed  part,  is  far 
from  being  a  constant  phenomenon  ;  being  most  frequent  when  the  subjects  of 
the  disease  are  persons  in  weak  health,  or  of  the  tuberculous  diathesis,  as  has 
been  remarked  also  by  Nasse  and  Popp.3  And  Mr.  Paget  has  furnished  a  re- 
markable confirmation  of  this  view,  in  the  observation,  that  the  inflammatory 
exudations  produced  in  different  individuals,  by  the  application  of  the  same 
stimulus  on  the  same  tissue  (e.  g.  by  the  action  of  a  blister  on  the  skin)  are 
found  to  present  a  predominance  of  the  fibrinous  or  of  the  corpuscular  element, 

1  "Philosophical  Magazine,"  May,  1845. 

2  "Lectures  on  Inflammation,"  in  "Medical  Gazette,"  1850,  vol.  xlv.  pp.  972,  973. 


206  OF   THE   BLOOD. 

according  to  the  general  condition  of  the  patient.  "  The  highest  health  is 
marked  by  an  exudation  of  the  most  perfect  and  unmixed  fibrin  j  the  lowest, 
by  the  most  abundant  corpuscles,  and  by  their  nearest  approach,  even  in  their 
early  state,  to  the  characters  of  pus-cells.  The  degrees  of  deviation  from 
general  health  are  marked,  either  by  increasing  abundance  of  the  corpuscles, 
their  gradual  predominance  over  the  fibrin,  and  their  gradual  approach  to 
the  character  of  pus-cells,  or  else  by  the  gradual  deterioration  of  fibrin, 
which  from  being  tough,  elastic,  clear,  uniform,  and  of  filamentous  appear- 
ance, or  filamentous  structure,  becomes  less  and  less  filamentous,  softer,  more 
paste-like,  turbid,  nebulous,  dotted,  and  mingled  with  minute  oil-globules ." 
" After  some  practice,"  adds  Mr.  Paget,  "one  might  form  a  fair  opinion  of  the 
degree  in  which  a  patient  was  cachectic,  and  of  the  degree  in  which  an  inflam- 
mation in  him  would  tend  to  the  adhesive  or  to  the  suppurative  character  by 
the  microscopic  character  of  these  exudations."1 — From  such  evidence  we  seem 
forced  to  the  conclusion  that,  whether  or  not  the  Colorless  corpuscles  are  to  be 
regarded  in  any  other  light  than  as  blood-cells  not  yet  fully  developed,  their 
multiplication  is  not  (as  has  been  maintained)  the  source  of  increase  in  the 
fibrinous  constituent  of  the  liquor  sanguinis.3  Whether  the  arrest  of  develop- 
ment of  these  corpuscles,  in  the  abnormal  conditions  just  referred  to,  is  to  be 

1  Op.  cit.,  p.  1015. 

2  The  Author  is  not  ashamed  thus  to  record  his  withdrawal  of  an  opinion  which  he 
formerly  held,  and  for  which  he  even  strenuously  contended.     His  belief  was  founded  in 
great  part  upon  the  assertions  of  Mr.  Addison  ("Experimental  Researches  on  the  Process 
of  Nutrition/'  First  and  Second  Series),  and  of  Dr.  C.  J.  B.  Williams  ("Principles  of 
Medicine,"  second  edit.  pp.  258 — 266),  as  to  the  uniform  concurrence  of  an  increased 
production  of  Colorless  corpuscles  with  the  augmentation  of  Fibrin  usually  regarded  as 
characteristic  of  the  inflammatory  state ;  and  this  having  been  disproved  by  the  researches 
of  Mr.  Paget  and  other  trustworthy  observers,  he  abandons  the  idea  as  one  no  longer  tenable. 
He  has  the  satisfaction  of  finding,  however,  that  Mr.  Wharton  Jones  has,  on  his  side,  given 
up  the  doctrine  that  the  Red  corpuscles  dissolve  into  the  fibrin  of  the  blood ;  against  which 
the  Author  had  argued,  whilst  endeavoring  to  substantiate  his  own.     Mr.  Wharton  Jones 
appears  to  be  now  satisfied  that  "  the  inverse  proportion  in  the  quantity  of  red  corpuscles 
and  fibrin,  though  frequent,  has  not  always  been  found  to  obtain ;  and  when  found,  the 
diminution  in  the  red  corpuscles  has  not  been  in  any  regular  relation  to  the  increase  in  the 
quantity  of  fibrin;  moreover,  the  quantity  of  red  corpuscles  which  disappear  is  quite 
disproportionate  to  the  comparatively  small  addition  to  the  quantity  of  fibrin."     (See  his 
Prize  Essay  "  On  the  State  of  the  Blood  and  the  Bloodvessels  in  Inflammation,"  in  the 
"Guy's  Hospital  Reports"  for  1850,  p.  68.)     Still,  the  above  observations  of  Mr.  Paget 
and  others  seem  to  indicate  some  relation  of  reciprocity  between  the  Colorless  corpuscles 
and  the  fibrin ;  while  those  of  Mr.  Newport  (g  195)  favor  the  belief  that  these  corpuscles 
may  melt  down  into  a  substance  adapted  for  the  nutrition  of  the  tissues.     An  observation 
of  Mr.  Addison' s  too,  which  the  Author  has  himself  confirmed,  appears  to  sanction  the 
idea  (although  it  by  no  means  proves)  that  the  colorless  corpuscles  emit  a  fibrillating  material 
in  bursting.     (See  his   "Experimental  Researches,"  second  series,   p.  4.)     The  Author 
cannot  help  still  suspecting,  therefore,  that  the  Colorless  corpuscles  are  not  to  be  regarded 
merely  as  red  blood-cells  in  their  earlier  phase  of  development ;  but  that  they  have  some 
special  connection  with  the  elaboration  of  the  plastic  constituents  of  the  blood.     Warned, 
however,  by  previous  experience,  of  the  danger  of  building  conclusions  upon  observations 
of  a  limited  and  imperfect  character,  he  refrains  at  present  from  offering  any  hypothesis 
as  to  the  nature  of  that  relation — merely  suggesting  that  it  is  far  from  certain  that  all  the 
bodies  which  pass  under  the  designation  of  "white"  or  "colorless  corpuscles,"  are  of  the 
same  kind,  as  is  shown  by  the  fact  that  cells  are  formed  in  exudations,  which  cannot  be 
distinguished  from  the  colorless  cells  of  the  blood,  and  which  yet  can  scarcely  be  supposed 
to  be rudimental  red  corpuscles ;  and  that  if  some  of  the  "colorless  corpuscles"  of  the 
blood  be  looked  upon  as  instrumental  in  elaborating  its  plastic  components,  whilst  others 
are  on  the  march  of  development  into  red  corpuscles,  it  seems  very  probable  that  the  same 
depressing  influence  which  checks  the  latter  process  should  also  interfere  with  the  former, 
and  that  thus  an  accumulation  of  colorless  corpuscles  in  cachectic  subjects  may  coincide 
with  a  diminution  in  the  red,  and  at  the  same  time  with  an  imperfect  elaboration  of  the 
fibrin  of  their  blood. 


ITS  VITAL  PROPERTIES,,  AND  RELATIONS  TO  LIVING  ORGANISM.     207 

attributed  to  an  original  want  of  capacity  in  their  germs,  or  to  some  agency 
which  subsequently  depresses  their  vital  power,  or  to  the  want  of  some  material 
which  they  require  for  the  purpose,  can  scarcely  at  present  be  decided ;  and  it 
may  be  doubted  whether  any  one  of  these  determining  causes  is  in  action  in 
every  case,  or  whether  each  of  them  may  not  occasionally  operate,  either  singly 
or  in  combination. 

197.  Turning  now  to  those  constituents  of  the  Blood  which  show  no  indi- 
cations of  possessing  vitality,  we  have  first  to  speak  of  its  Albumen.     The  rela- 
tions which  this  substance  bears  to  the  living  body  are  of  the  most  important 
and  fundamental  character ;  since,  as  already  shown  (§  20),  it  is  the  original 
pabulum  at  the  expense  of  which  all  the  solid  tissues  are  generated,  whilst  it 
also  affords  the  material  for  the  production  of  the  fibrin,  the  globulin,  and  the 
haematin  of  the  blood  itself.     It  appears,  however,  to  be  itself  entirely  destitute 
of  formative  capacity ;  for  in  no  exudation  which  is  purely  serous  do  we  ever 
trace  the  slightest  indication  of  organization  ;  and  its  conversion  into  the  various 
kinds  of  tissue,  therefore,  must  be  entirely  due  to  their  own  power  of  appropri- 
ating and  transforming  it.1     The  great  function  of  the  Albumen  of  the  blood, 
then,  is  to  supply  the  material  for  these  various  transformations;  and  we  ac- 
cordingly find  that  whatever  other  changes  the  fluid  may  undergo,  whether  it 
loses  its  fibrin  or  its  red  corpuscles,  or  both,  albumen  is  still  present  in  abund- 
ance.    Its  ultimate  source  is  to  be  found  in  the  food ;  but  the  serous  liquid 
which  percolates  the  tissues  of  the  body  may  be  looked  upon  as  a  reserve-store 
to  be  drawn  upon  in  case  of  need,  furnishing  albumen  to  the  blood  when  it 
might  otherwise  be  deficient ;  and  thus  perhaps  it  is  that  abstinence  or  repeated 
losses  of  blood  do  not  produce  the  degree  of  depression  in  the  proportion  of 
albumen  which  might  be  expected  from  the  very  marked  reduction  which  they 
effect  in  that  of  the  corpuscles.2     When  an  excess  of  Albuminous  matter  is  in- 
gested as  food,  the  injurious  effects  which  might  follow  the  too  great  augmen- 
tation of  this  constituent  of  the  Blood,  appear  to  be  averted  by  the  readiness 
with  which  it  undergoes  retrograde  as  well  as  progressive  metamorphoses ;  for, 
if  not  speedily  subjected  to  the  latter  change,  it  appears  to  be  affected  by  decom- 
posing agencies,  and  to  be  eliminated  from  the  system  by  the  excretory  appara- 
tus,  under  the   form  of  urinary  and  biliary  matter.     (See  CHAP,  xn.)     As 
already  pointed  out,  however,  although  Albumen  seems  to  furnish  certain  con- 
stituents of  secretions  which  are  applied  to  special  purposes  within  the  body,  yet 
its  passage  as  such  into  the  excretions  must  be  looked  upon  as  quite  abnormal, 
and  as  (so  to  speak)  a  mere  waste  of  nutrient  material  (§  21). 

198.  The  Fatty  matters  of  the  Blood  are  obviously  destined  to  furnish  the 
contents  of  the  adipose  and  nervous  vesicles;  whilst  their  presence  seems  also 
to  be  required  in  the  early  stages  of  the  production  of  cells  generally  (§  42). 

1  Those  who  maintain  that  Fibrin  is  the  only  organizable  constituent  of  the  blood,  and 
that  it  is  the  immediate  source  of  the  nutrition  of  the  tissues  generally,  consider  that  Al- 
bumen cannot  be  appropriated  by  the  tissues  without  first  passing  through  the  Condition 
of  fibrin.     This  doctrine,  formerly  contended  for  by  the  Author,  he  now  abandons  as  in- 
consistent with  much  that  we  know  of  the  history  of  fibrin  and  of  its  destination  in  the 
body  ($  192) ;  and  he  would  rest  upon  the  simple  fact  that  the  first  development  of  the 
embryonic  mass,  by  the  multiplication  of  its  component  cells,  takes  place  in  a  fluid  in  which 
nothing  analogous  to  fibrin  can  be  discovered,  as  showing  that  cells  are  able  to  draw  their 
support  directly  from  an  albuminous  pabulum ;  whilst  it  is  only  when  the  gelatinous  tissues 
begin  to  be  formed  in  the  embryo  that  we  find  its  blood  to  become  spontaneously  coagu- 
lable. 

2  It  is  to  be  remembered,  however,  that  the  whole  mass  of  the  blood  (liquid  as  well  as 
solid)  is  probably  reduced  under  these  circumstances ;  it  having  been  found  by  the  experi- 
ments of  Chossat  ("RecherchesExperimen tales  sur  1'Inanition"),  that  when  animals  were 
killed  by  starvation,  the  blood  lost  no  less  than  75  per  cent,  of  its  weight,  whilst  the  ave- 
rage loss  of  the  whole  body  was  40  per  cent. 


208  OP   THE   BLOOD. 

One  of  the  principal  sources  of  their  expenditure,  however,  is  that  combustive 
process  by  which  the  heat  of  the  body  is  maintained ;  and  the  amount  deposited 
in  the  tissues  as  fat  may  be  looked  upon  as  the  surplus  of  the  quantity  ingested 
that  is  not  thus  consumed.  The  quantity  of  fatty  matter  in  the  blood  is  liable 
to  sudden  augmentation,  from  the  introduction  of  a  large  quantity  furnished  at 
once  by  the  alimentary  material ;  and  this  excess  will  continue  until  the  surplus 
has  been  eliminated,  either  by  the  combustive,  the  nutritive,  or  the  excretory 
operations.  These  last  do  not  ordinarily  remove  the  saponifiable  fats  from  the 
body ;  for  although  the  mammary  secretion  in  the  female  draws  off  from  her 
blood  a  large  quantity  of  fatty  matter,  this  is  destined  not  for  its  purification, 
but  for  the  nutrition  of  her  offspring;  and  cholesterin  appears  to  be  the  only 
fatty  substance  which  is  normally  excreted  for  the  purpose  of  removing  it  from 
the  body.  Fatty  matters  are  often  detectable  in  small  quantities  in  the  healthy 
feces,  where,  however,  their  presence  may  be  attributed  to  the  non-absorption 
of  a  portion  of  those  which  the  food  had  included ;  and  this  want  of  absorption 
seems  especially  to  occur  in  cases  in  which  the  action  of  the  Pancreas  is  disturbed 
by  disease  of  that  organ.1  But  they  are  sometimes  discharged  in  such  large 
quantities  that  it  is  scarcely  possible  thus  to  account  for  their  presence ;  and  it 
would  seem  that  they  must  have  been  poured  into  the  alimentary  canal  either 
by  the  liver  or  by  some  other  excreting  organ,  which  must  have  drawn  them  off 
from  the  blood.  It  does  not  seem  an  improbable  surmise  that  in  such  cases 
there  may  be  an  extraordinary  tendency  to  the  metamorphosis  of  albuminous  and 
other  azotized  matters  (whether  furnished  by  the  tissues  or  by  the  food)  into  fat 
(§  40)  ;  and  that  the  excretion  of  this  substance  does  in  effect  tend  to  keep  down 
their  proportion  in  the  blood.  Their  occasional  extraordinary  accumulation  in 
the  circulating  fluid  (§  176)  tends  to  confirm  this  view ;  for  it  appears  scarcely 
possible  that  such  an  enormous  proportion  of  fat  could  have  been  derived  from 
the  food,  either  in  the  condition  of  fat,  or  in  that  of  a  saccharine  compound 
capable  of  being  converted  into  it. 

199.  All  the  other  Organic  compounds  which  have  been  distinctly  recognized 
in  the  blood,  or  of  whose  presence  in  the  circulating  current  we  have  inferential 
evidence — sugar,  lactic  acid,  urea,  uric  acid,  hippuric  acid,  creatine,  creatinine, 
the  volatile  fatty  acids,  and  the  odorous  substances — are  to  be  considered  not  as 
in  any  way  subservient  to  those  constructive  changes  in  which  Nutrition  pro- 
perly consists,  but  as  products  of  the  retrograde  metamorphosis  either  of  the 
alimentary  materials  or  of  the  tissues  themselves,  and  as   on  their  way  to  be 
eliminated  from  the  blood,  either  by  the  respiratory  organs,  or  by  some  other 
part  of  the  excretory  apparatus.    And  the  more  perfect  the  balance  between  the 
action  of  this  apparatus, 'and  the  operations  whereby  these  compounds  are  gene- 
rated, the  less  will  be  the  proportion  in  which  they  present  themselves  in  the 
blood,  and  the  greater  will  be  the  difficulty  in  detecting  them  there. 

200.  The  uses  of  the  various  Inorganic  compounds,  which,  as  being  uniformly 
present  in  the  Blood,  must  be  considered  among  its  integral  constituents,  are  not 
as  yet  by  any  means  positively  known;  yet  great  advances  have  been  recently 
made  towards  this  knowledge;  and  it  may  be  pretty  certainly  affirmed  that  the 
presence  of  some  of  them  has  reference  to  the  peculiar  functions  and  conditions 
of  the  blood  itself,  whilst  others  are  chiefly  destined  for  appropriation  by  the 
tissues  to  whose  growth  it  ministers.     Thus  the  phosphate  and  carbonate  of 
soda  would  seem  to  have  it  for  their  chief  purpose,  to  maintain  the  alkalinity  of 
the  blood,  on  which  its  other  properties  so  much  depend  (§  83),  and  to  increase 
the  absorptive  power  of  the  serum  for  gases  (§  84);  the  salts  of  potash,  on  the 
other  hand,  appear  to  be  specially  required  for  the  nutrition  of  muscular  tissue 
(§  85);  whilst  the  presence  of  chloride  of  sodium  is  needed  alike  for  the  con- 

1  See  Mr.  A.  Clark,  in  the  "  Lancet"  for  Aug.  16,  1851. 


ITS  VITAL  PROPERTIES,  AND  RELATIONS  TO  LIVING  ORGANISM.     209 

servation  of  the  organic  elements  of  the  blood  in  their  normal  condition,  and  for 
the  supply  of  the  salt  which  is  required  as  a  component,  not  only  of  the  solid 
tissues,  but  also  of  all  the  secreted  fluids  (§  82).  The  presence  of  the  Earthy 
salts,  on  the  other  hand,  would  seem  to  have  reference  almost  exclusively  to  the 
composition  of  the  tissues,  into  which  some  of  them  enter  very  largely.  The 
phosphate  of  lime  in  particular  must  be  regarded  almost  in  the  light  of  a  histo- 
genetic  substance,  so  constantly  does  it  seem  to  be  present  in  newly-forming 
tissues ;  whilst  it  is  also  in  great  demand  as  the  principal  consolidating  material 
of  bone  and  tooth  (§86).  Whether  the  carbonate  of  lime,  the  phosphate  of  mag- 
nesia, the  fluoride  of  calcium,  and  the  silica  of  the  blood,  are  of  any  other  use 
in  it  than  to  supply  consolidating  materials  for  the  tissues,  there  is  at  present  no 
evidence  whatever.  Iron,  like  the  alkaline  salts,  is  an  essential  constituent  of 
the  blood  itself,  forming  a  very  large  percentage  of  the  haematin  of  its  red  cor- 
puscles ;  and  it  is  supplied  by  the  blood  to  various  tissues,  especially  the  muscles 
and  the  hair,  of  which  also  it  may  be  considered  an  essential  component  (§  87). — 
The  normal  proportions  of  all  these  substances  appear  to  be  chiefly  maintained 
by  means  of  the  excretory  apparatus,  which  filters  off  (so  to  speak)  any  surplus; 
it  being  through  the  urinary  organs  that  they  are  chiefly  eliminated.  And  it  is 
by  them,  too,  that  the  normal  proportion  of  Water  in  the  blood  is  chiefly  main- 
tained; the  Malpighian  apparatus  of  the  kidneys  apparently  acting  as  a  kind  of 
safety-valve,  through  which  any  surplus  that  remains  after  the  cutaneous,  pul- 
monary, and  intestinal  exhalants  have  performed  their  appropriate  duties,  is 
allowed  to  make  its  escape. 

201.  It  is  not  alone  by  the  proper  Excretory  apparatus,  however,  that  the 
fitness  of  the  Blood  for  circulation  through  the  body  is  maintained.  Every 
tissue  draws  from  the  circulating  fluid  some  particular  material,  or  combination 
of  materials,  which  constitutes  its  own  special  pabulum  ;  and  as  the  "pabulum" 
of  each  tissue  is  different,  it  follows  that  the  normal  composition  of  the  blood 
can  only  be  preserved,  without  waste  of  substance,  by  the  existence  of  such  a 
balance  between  the  appropriative  action  of  the  several  parts,  as  shall  cause  a 
certain  equivalent  of  blood  to  supply,  without  deficiency  or  surplus,  the  materials 
which  they  collectively  require.  Such  a  balance  is,  in  fact,  ordinarily  preserved; 
and  its  maintenance  is  one  of  the  most  marvellous  of  those  exemplifications  of 
Design,  which  the  vital  economy  of  the  body  presents  in  no  less  a  degree  than 
its  organized  structure ;  an  exemplification,  however,  which  becomes  yet  more 
marvellous,  when  it  is  shown  that  not  only  every  kind  of  tissue,  but  every  spot 
of  every  organ,  has  its  own  special  "  pabulum;"  drawing  something  from  the 
blood,  which  is  different  from  that  appropriated  by  every  other  part  of  the  body, 
save  by  the  corresponding  spot  on  the  opposite  side.  This  position  seems  fully 
established  by  the  researches  of  Dr.  W.  Budd  and  of  Mr.  Paget  on  "Symmetrical 
Diseases"1  the  phenomena  of  which  are  full  of  interest,  as  illustrating  the  ordi- 
nary operations  of  Nutrition.  Excluding  the  cases  of  congenital  symmetrical 
defects,  and  a  few  which  seem  to  depend  on  morbid  influence  of  the  nervous 
system,  it  may  be  stated  as  a  general  fact,  that  all  symmetrical  diseases  depend 
on  the  presence  of  some  morbid  material  in  the  blood,  which  usually  enters  into 
combination  with  the  tissue  that  is  diseased,  or  with  the  organized  product  of 
the  morbid  process.  Such  a  substance  fastens  upon  certain  spots  or  islands  on 
one  side  of  the  body,  leaving  the  surrounding  parts  unaffected;  and  precisely 
similar  spots  or  islands  are  affected  in  like  manner  on  the  other  side.  The  con- 
clusion seems  unavoidable,  that,  however  closely  one  portion  of  skin  or  bone 
may  seem  to  resemble  another,  the  only  parts  that  are  exactly  alike  are  those 
which  repeat  each  other  symmetrically  on  the  opposite  sides  of  the  body;  for, 
although  no  power  of  artificial  chemistry  may  determine  the  difference,  the 

1  See  their  original  Essays  on  this  subject  in  the  "Med.-Chir.  Trans."  vol.  xxv. 
14 


210  OF   THE  BLOOD. 

chemistry  of  the  living  body  makes  it  evident,  the  morbid  material  testing  out 
the  parts  for  which  it  has  the  greatest  affinity,  uniting  with  these  alone,  and 
passing  by  the  rest.  It  is  continually  observable,  moreover  (as  Mr.  Paget  has 
remarked),  that  a  poison  of  the  same  kind  will  attack  corresponding  spots,  not 
merely  on  the  two  sides  of  a  single  individual,  but  also  on  the  two  sides  of  any 
others  who  may  have  imbibed  it  into  their  systems.  Thus  the  syphilitic  poison 
has  its  "  seats  of  election"  when  it  begins  to  attack  the  bones,  fixing  upon  cer- 
tain parts  of  the  tibiae  and  of  the  skull  with  great  uniformity;  and  in  the  Hun- 
terian  Museum  are  the  pelves  of  two  lions,  on  both  of  which  new  osseous  deposit 
has  taken  place  (as  the  product  of  some  disease  resembling  rheumatism  in  man) 
in  a  most  complex  and  irregular  pattern,  this  being  so  similar  in  the  two,  that 
almost  every  spot  and  line  of  the  one  is  represented  in  the  other,  with  an  exact- 
ness only  inferior  to  the  symmetrical  correspondence  between  the  two  sides  of 
each.1  It  has  been  further  pointed  out  by  Dr.  W.  Budd,  as  indicated  by  the 
phenomena  of  these  diseases,  that,  next  to  the  parts  which  are  symmetrically 
placed,  none  are  so  nearly  identical  in  composition  as  those  which  are  analogous, 
such  as  the  corresponding  parts  of  the  superior  and  inferior  extremities. — All 
these  facts  tend  to  demonstrate  the  perfect  and  most  minute  exactness  of  the 
adaptation  which  must  exist  in  the  state  of  health  between  the  blood  and  all  the 
tissues,  as  well  as  the  almost  inconceivable  minuteness  of  the  departure  from 
this  adaptation  which  may  become  a  source  of  disease ;  and  it  is  a  sure  indication 
of  the  safety  with  which  we  may  found  such  inferences  upon  them,  that  the 
phenomena  of  symmetrical  disease  are  most  distinct,  when  the  disordered  action 
is  most  conformable,  as  to  its  character  and  its  rate,  to  the  normal  nutrition  of 
the  structure ;  it  being  in  diseases  which  (though  dependent  upon  a  poison  in 
the  blood)  are  of  an  inflammatory  or  other  violent  nature,  that  the  symmetry  of 
the  morbid  change  is  least  obvious. 

202.  Thus,  then,  we  are  led  to  the  conclusion  that,  as  Treviranus  phrased 
it,  "each  single  part  of  the  body,  in  respect  of  its  nutrition,  stands  to  the  whole 
body  in  the  relation  of  an  excreted  substance ;"  or,  in  other  words,  each  part 
of  the  body,  by  taking  from  the  blood  the  peculiar  substances  which  it  needs 
for  its  own  nutrition,  does  thereby  act  as  an  excretory  organ,  inasmuch  as  it 
removes  from  the  blood  that  which,  if  retained  in  it,  would  be  injurious  to  the 
nutrition  of  the  body  generally.  Thus,  the  phosphates  which  are  deposited  in 
our  bones,  are  as  effectually  excreted  from  the  blood,  and  as  completely  pre- 
vented from  acting  injuriously  on  other  tissues,  as  those  which  are  discharged 
with  the  urine. — The  applications  of  this  doctrine  have  been  greatly  extended 
by  Mr.  Paget,  who  has  given  the  following  among  other  examples  of  its  bearing 
upon  the  general  relations  between  the  blood  and  the  tissues.  The  hairy  cover- 
ing may  be  considered  to  serve,  over  and  above  its  local  purposes,  for  the  removal 
of  certain  components  of  the  blood,  which  would  be  injurious  to  its  constitution 
if  they  remained  and  accumulated  in  it ;  and  accordingly  we  do  not  find  that  its 
development  is  delayed,  until  near  the  period  when  its  protection  will  be  required ; 
for  a  complete  coat  (the  lanugo  of  the  human  foetus)  is  formed  in  the  foetus  of 
mammals  generally,  whilst  they  are  still  within  the  uterus,  removed  from  all  those 
conditions  against  which  hair  is  a  defence;  and  this  coat  is  shed  very  soon  after 
birth,  being  replaced  by  another  of  wholly  different  color,  the  growth  of  which  had 
begun  within  the  uterus.  The  same  principle  leads  to  the  apprehension  of  the 
true  import  of  the  hair  which  exists  in  a  kind  of  rudimental  state  on  the  general 
surface  of  our  bodies ;  and  thence  to  the  real  meaning  of  the  existence  of  other 
organs  which  permanently  remain  in  a  rudimental  state,  such  as  the  mammary 
glands  of  the  male.  For,  as  Mr.  Paget  justly  remarks  (loc.  cit.),  "  these  rudi- 

1  See  Mr.  Paget's  "Lectures  on  Nutrition,  &c.,"  in  the  "Medical  Gazette"  for  1847: 
Lect.  I. 


ITS  VITAL  PROPERTIES,  AND  RELATIONS  TO  LIVING  ORGANISM.     211 

mental  organs  certainly  do  not  serve,  in  a  lower  degree,  the  same  purposes  as 
are  served  by  the  homologous  parts  which  are  completely  developed  in  other 
species,  or  in  the  other  sex.  To  say  they  are  useless,  is  contrary  to  all  we  know 
of  the  absolute  perfection  and  all-pervading  purpose  of  creation ;  to  say  they 
exist  merely  for  the  sake  of  conformity  to  a  general  type  of  structure,  is  surely 
unphilosophical,  for  the  law  of  unity  of  organic  types  is,  in  larger  instances,  not 
observed,  except  when  its  observance  contributes  to  the  advantages  of  the  indi- 
vidual. No :  all  these  rudimental  organs  must,  as  they  grow,  be  as  excretions 
serving  a  definite  purpose  in  the  economy,  by  removing  their  appropriate  mate- 
rials from  the  blood,'  thus  leaving  it  fitter  for  the  nutrition  of  other  parts,  or 
adjusting  the  balance  which  might  otherwise  be  disturbed  by  the  formation  of 
some  other  part.  Thus  they  minister  to  the  self-interest  of  the  individual ; 
while,  as  if  for  the  sake  of  wonder,  beauty,  and  perfect  order,  they  are  con- 
formed with  the  great  law  of  unity  of  organic  types,  and  concur  with  the  uni- 
versal plan  observed  in  the  construction  of  organic  beings." 

203.  But  further,  it  has  been  already  pointed  out  (§  120)  that  the  presence 
of  a  certain  substance  in  the  Blood,  appears  to  determine  the  formation  of  the 
tissue  of  which  that  substance  is  the  appropriate  pabulum.  And  thus,  as  the 
abstraction  of  the  material  required  for  each  part  leaves  the  blood  in  a  state 
fitted  for  the  nutrition  of  other  parts,  it  seems  to  follow,  as  Mr.  Paget  has 
further  remarked  (Op.  cit.,  Lect.  II.),  that  such  a  mutual  dependence  exists 
amongst  the  several  parts  and  organs  of  the  body,  as  causes  the  evolution  of 
one  to  supply  the  conditions  requisite  for  the  production  of  another ;  and  hence, 
that  the  order  in  which  the  several  organs  of  the  body  appear  in  the  course  of 
development,  while  it  is  conformable  to  the  law  of  imitation  of  the  parent,  and 
to  the  law  of  progressive  ascent  towards  the  higher  grade  of  being,  is  yet  the 
immediate  result  of  changes  effected  in  the  condition  of  the  blood  by  the  ante- 
cedent operations.  And  this  view  is  confirmed  by  many  circumstances  which 
indicate,  that  certain  organs  really  do  stand  in  such  a  complemental  relation  to 
one  another  as  it  implies  ]  a  large  class  of  facts  of  this  order  being  supplied  by 
the  history  of  the  evolution  of  the  generative  apparatus,  and  by  that  of  the 
concurrent  changes  in  other  organs  (especially  the  tegumentary)  which  are 
found  to  be  dependent  upon  it,  although  there  is  no  direct  functional  relation 
between  them.  Thus,  the  growth  of  the  beard  in  man  at  the  period  of  puberty, 
is  but  a  type  of  a  much  more  important  change  which  takes  place  in  many 
animals  with  every  recurrence  of  the  period  of  generative  activity.  This  is 
most  obvious  in  birds,  whose  plumage  at  the  commencement  of  the  breeding 
season,  becomes  (especially  in  the  male)  more  highly  colored,  besides  being 
augmented  by  the  growth  of  new  feathers ;  but  when  the  sexual  organs  pass 
into  their  state  of  periodic  atrophy,  the  plumage  at  once  begins  to  assume  a 
paler  and  more  sombre  hue,  and  many  of  the  feathers  are  usually  cast,  their 
nutrition  being  no  longer  kept  up.  It  is  a  matter  of  common  observation,  that 
the  deficiency  of  hair  on  the  face  (where  this  is  not,  as  among  the  Asiatics,  a 
character  of  race)  is  usually  concurrent  with  a  low  amount  of  generative  power 
in  the  male,  and  may  be  considered  as  indicative  of  it ;  whilst,  on  the  other 
hand,  the  presence  of  hair  on  the  upper  lip  and  chin  of  the  female  is  indicative 
of  a  tendency  in  the  general  organization  and  mental  character  towards  the 
attributes  of  the  male,  and  of  a  deficiency  in  those  which  are  typical  of  the 
female.  If,  moreover,  the  development  of  the  male  organs  be  prevented,  the 
evolution  of  the  beard  does  not  take  place ;  whilst  the  cessation  or  the  absence 
of  activity  in  the  female  organs  is  often  attended  by  a  strong  growth  of  hair  on 
the  face,  as  well  as  by  other  changes  that  may  be  attributed  to  the  presence  of 
some  special  nutritive  material  in  the  blood,  for  which  there  is  no  longer  any 
other  demand.  This,  again,  shows  itself  yet  more  strongly  in  Birds ;  among 


212  OF   THE   BLOOD. 

which  (as  Hunter  long  since  pointed  out1)  it  is  no  uncommon  occurrence  for 
the  female,  after  ceasing  to  lay,  to  assume  the  plumage  of  the  male,  and  even 
to  acquire  other  characteristic  parts,  as  the  spurs  in  the  fowl  tribe.  Moreover, 
it  has  been  ascertained  by  the  experiments  of  Sir  Philip  Egerton,  that  if  a  buck 
be  castrated  while  his  antlers  are  growing  and  still  covered  with  the  "  velvet," 
their  growth  is  checked,  they  remain  as  if  truncated,  and  irregular  nodules  of 
bone  project  from  their  surfaces;  whilst  if  the  castration  be  performed  when  the 
antlers  are  full  grown,  these  are  shed  nearly  as  usual  at  the  end  of  the  season, 
but  in  the  next  season  are  only  replaced  by  a  kind  of  low  conical  stumps. 

204.  That  these  and  similar  changes  in  the  development  of  organs  are  imme- 
diately determined  by  the  condition  of  the  circulating  fluid,  that  is,  by  the  pre- 
sence or  absence  of  the  appropriate  "pabulum"  for  the  parts  in  question,  would 
further  seem  likely  from  the  fact,  that  they  may  be  artificially  induced  by  cir- 
cumstances which  directly  affect  the  condition  of  the  blood.     This  has  been 
shown  by  Mr.  Yarrell,3  in  regard  to  the  assumption  of  the  male  plumage  by  the 
female;  and  a  still  more  remarkable  and  satisfactory  proof  is  furnished  by  the 
conversion  of  the  "worker"  larva  of  the  Bee  into  a  perfect  "queen,"  solely 
through  a  change  of  diet.3     And  thus  we  are  led  to  feel  that  Mr.  Paget's  doc- 
trine of  "complementary  nutrition,"  whilst  it  has  the  advantage  of  grouping 
together  a  great  number  of  phenomena  which  would  otherwise  seem  to  be  unre- 
lated to  each  other,  really  possesses  a  definite  foundation  in  well-known  and  uni- 
versally-admitted facts,  which  can  scarcely  be  viewed  in  any  other  light.     To 
use  his  own  expression  of  it,  "  the  development  of  each  organ  or  system,  co- 
operating with  the  self-development  of  the  blood,  prepares  it  for  the  formation 
of  some  other  organ  or  system,  till,  by  the  successive  changes  thus  produced, 
and  by  its  own  development  and  increase,  the  blood  is  fitted  for  the  main- 
tenance and  nutrition  of  the  completed  organism."     And  further,  "  where  two 
or  more  organs  are  manifestly  connected  in  nutrition,  and  not  connected  in  the 
exercise  of  any  external  office,  their  connection  is  because  one  is  partly  formed 
of  materials  left  in  the  blood  by  the  formation  of  the  other ;  so  that  each,  at  the 
same  time  that  it  discharges  its  own  proper  and  external  office,  maintains  the 
blood  in  the  condition  most  favorable  to  the  development  of  the  other." 

205.  Thus,  then,  the  precise  condition  of  the  Blood  at  any  one  time  is 
dependent  upon  a  vast  variety  of  antecedent  circumstances,  and  can  scarcely  be 
the  same  at  any  two  periods  of  life.     Yet  we  find  that,  taken  as  a  whole,  it  ex- 
hibits such  a  remarkable  constancy  in  its  leading  features,  that  we  can  scarcely 
fail  to  recognize  in  it  some  such  capacity  for  self-development  and  maintenance, 
as  that  which  the  solid  tissues  are  admitted  to  possess.     And  this  idea  may  be 
thought  less  strange,  when  it  is  borne  in  mind  that  the  first  blood  is  formed  by 
the  liquefaction  of  the  primordial  cells  of  the  embryo,  and  that,  notwithstand- 
ing the  continual  change  in  its  components,  it  still  retains  its  identity  through 
life,  in  no  less  a  degree  than  a  limb  or  an  eye,  the  material  changes  in  which, 
though  less  rapid,  are  not  less  complete.     Looking,  again,  to  the  undoubted 
vitality  of  the  Corpuscles,  and  to  the  strong  ground  for  regarding  the  Fibrin 
also  as  an  instrument  of  vital  force,  we  cannot  but  perceive  that  the  Life  of  the 
Blood  is  as  legitimate  a  phrase,  and  ought  to  carry  as  much  meaning  in  it,  as 
the  Life  of  a  Muscle.     And  as  the  one  has  a  period  of  growth,  development, 
and  decline,  so  must  the  other. — This  view  is  borne  out,  not  merely  by  those 
palpable  differences  in  the  composition  of  the  blood  at  different  ages,  which  are 
detectable  by  our  rude  methods  of  examination ;  but  also  by  those  alterations  in 

1  "  Account  of  an  Extraordinary  Pheasant,"  in  "  Hunter's  Works,"  Palmer's  edit.  vol.  iv. 
p.  44. 

2  "Philosophical  Transactions,"  1827. 

»  "Princ.  of  Phys.,  Gen.  and  Corap.,"  g  60,  Am.  Ed. 


ITS  VITAL  PROPERTIES,  AND  RELATIONS  TO  LIVING  ORGANISM.     213 

the  tendency  to  particular  constitutional  diseases,  which  at  the  same  time  mark 
the  advance  of  life,  and  indicate  minute  and  otherwise  inappreciable  alterations 
in  the  circulating  fluid.  For  it  is  obvious  that  since  the  poison  of  smallpox, 
for  example,  less  readily  produces  its  characteristic  "zymosis"  in  the  blood  of 
the  adult  than  it  does  in  that  of  the  child,  the  latter  must  differ  from  the  former, 
either  in  composition  or  in  vital  endowments;  and  that  since  the  tendency  to 
"  fatty  degeneration"  of  the  tissues  generally  shows  itself  in  a  far  stronger  de- 
gree in  the  aged  person  than  in  the  adult,  this  is  likely  to  be  in  part  owing  to 
the  condition  of  the  blood,  in  which,  according  to  the  observations  of  Becquerel 
and  Rodier,  there  is  a  decided  and  progressive  increase  of  cholesterin  after  the 
age  of  40  or  50  years. 

206.  Thus,  then,  we  seem  justified  in  the  belief  that  the  Blood,  like  the  solid 
tissues,  has  a  formative  power  of  its  own,  which  it  exerts  in  the  appropriation 
of  the  new  material  supplied  to  it  from  the  food ;  and  that,  like  all  the  other 
parts  descended  from  the  component  cells  of  the  germinal  mass,  it  goes  through 
a  succession  of  phases,  which  are  partly  the  cause  and  partly  the  effect,  of  de- 
velopmental changes  in  the  organism  generally.     So  long  as  the  operations  of 
Nutrition  are  normally  carried  on,  the  materials  that  are  withdrawn  by  the  seve- 
ral parts  of  the  body  may  be  considered  so  far  to  balance  one  another,  that  no 
waste  is  incurred  from  this  source ;  and  if  the  amount  of  new  matter  introduced 
be  merely  the  equivalent  of  that  which  is  required  for  the  nutritive  operations, 
nothing  else  will  occasion  a  demand  for  elimination,  save  the  products  of  the 
disintegration  of  the  tissues,  which  are  received  back  into  the  blood  for  this 
purpose.     But  it  must  be  very  rarely  that  this  balance  is  precisely  maintained 
for  any  length  of  time,  since  a  multitude   of  circumstances  are  continually 
occurring  to  derange  it ;  the  most  frequent,  perhaps,  being  the  ingestion  of  cer- 
tain nutritive  materials  in  greater  quantity  than  they  are  required.     And  we 
then  find  that  the  organs  take  upon  themselves  a  supplemental  action  for  the 
removal  of  the  superfluity ;  the  kidneys  being  especially  charged  with  this  duty 
in  the  case  of  azotized  and  saline  matters,  and  the  liver  and  lungs  in  regard  to 
hydrocarbonaceous  substances.     It  is  obviously  of  importance,  however,  to  over- 
task  these  organs  as  little  as  possible ;  and  when  such  superfluity  is  becoming  a 
source  of  disease,  the  obvious  treatment  is  rather  to  prevent  it  from  being 
thrown  upon  them  for  separation,  by  diminishing  the  supply  of  aliment  gene- 
rally, or  of  some  particular  article  of  diet,  than  to  excite  them  to  increased 
activity  by  stimulating  medicines. 

207.  The  self-maintaining  power  of  the  Blood  is  yet  more  shown  in  the  phe- 
nomena of  Disease;  and  especially  in  its  spontaneous  recovery  of  its  normal 
condition,  after  the  most  serious  perversions ;  as  we  see  more  particularly  in 
febrile  diseases  of  definite  type  (such,  for  example,  as  the  Exanthemata,  Typhoid, 
Typhus,  &c.),  of  whose  origin  in  the  introduction  of  specific  poisons  into  the 
blood,  there  is  no  reasonable  ground  for  doubt.    In  studying  the  mode  in  which 
these  and  other  "morbid  poisons"  act  upon  the  blood,  and  through  it  upon  the 
system  at  large,  we  may  derive  important  assistance  from  a  previous  inquiry 
into  the  history  of  the  action  of  those  poisonous  agents,  which,  from  their  being 
more  readily  traceable  by  chemical  analysis,  can  be  more  satisfactorily  made  out. 
Such  an  inquiry  has  a  most  important  bearing  also,  on  the  modus  operandi  of 
medicines. — The  operation  of  medicinal  or  poisonous  substances  for  the  most 
part  depends  upon  the  power  which  they  possess,  when  introduced  into  the  cur- 
rent of  the  circulation,  of  effecting  some  determinate  change  in  the  chemical 
and  thereby  in  the  vital  condition,  either  of  the  components  of  the  blood,  or  of 
some  one  or  more  of  the  tissues  which  it  nourishes;  and  their  determination  to 
some  special  part  or  organ  must  be  attributed  to  the  same  kind  of  elective  affinity, 
as  that  by  which  the  normal  constituents  of  the  blood  are  so  determined  (§  201). 
Now  of  nearly  all  these  substances  it  may  be  said,  that  the  system,  if  left  to 


214  OF   THE   BLOOD. 

itself,  tends  to  free  itself  from  them,  provided  time  is  allowed  for  it  to  do  so ; 
and  that,  when  death  results  from  their  introduction  into  it,  the  fatal  result  is 
to  be  attributed  to  the  fact,  that  the  disorganization  of  structure  and  disturbance 
of  function  are  too  rapid  and  violent,  to  allow  the  eliminating  processes  to  be 
set  in  efficient  operation.  When  smaller  doses  are  taken,  their  effects  are  evan- 
escent, unless  the  abnormal  action  to  which  they  may  have  given  rise  is  of  a  kind 
to  perpetuate  itself;1  and  their  cessation  is  obviously  attributable  to  the  removal 
of  the  agent  from  the  system,  whereby  the  continuance  of  its  deleterious  agency 
is  prevented.  Of  this  removal,  we  have  of  course  the  most  satisfactory  evidence 
in  the  case  of  those  substances  which  can  be  detected  by  ordinary  chemical 
tests  in  the  excretions.  Thus,  as  a  general  rule,  alkaline,  and  earthy  salts  that 
have  been  absorbed  into  the  blood,  are  discharged  in  the  urinary  secretion, 
which  is  itself  increased  in  amount,  showing  that  their  action  is  specially  deter- 
mined towards  the  kidneys.  So  again  arsenic,  tartarized  antimony,  and  a 
variety  of  other  metallic  substances,  have  also  been  detected  in  the  urine,  for 
some  days  after  they  have  been  ingested;  showing  that  their  elimination  is  a 
work  of  time.  On  the  other  hand,  the  salts  of  copper  appear  rather  to  be  removed 
from  the  blood  by  the  liver,  and  also  by  the  bronchial  secretion.  And  lead, 
.which  passes  off  but  little  by  the  ordinary  excretions,  is  withdrawn  from  the 
circulation  by  various  tissues  and  organs,  but  particularly  by  certain  parts  of 
the  muscular  apparatus,  with  the  substance  of  which  it  becomes  incorporated, 
producing  a  most  injurious  influence  upon  its  vital  endowments.3 — The  only  ex- 
ception to  the  general  rule  above  stated,  seems  to  be  in  the  case  of  those  medi- 
cines, which  have  what  is  called  a  "cumulative"  tendency;  this  tendency  being, 
in  fact,  simply  the  result  of  their  want  of  stimulating  influence  upon  the  excre- 
tory organs,  whose  functional  activity  is  rather  impeded  than  promoted  by  them. 
This  is  pre-eminently  the  case  in  regard  to  lead,  which  is  probably  the  most 
cumulative  poison  with  which  we  are  acquainted;  its  continual  introduction  in 
doses  of  even  extreme  minuteness  being  capable,  if  sufficiently  prolonged,  of 
causing  the  most  serious  disturbance  in  almost  every  function  in  the  economy. 
Even  here,  it  is  rather  in  the  tissues  than  in  the  blood  that  it  accumulates — 
as  is  indicated  by  a  variety  of  facts,  but  more  especially  by  the  difficulty  with 
which  it  is  eliminated  from  the  system  by  means  that  would  be  probably  effectual 
in  removing  it  from  the  circulating  current; — and  thus  we  see  that,  in  default 
of  other  provisions  for  maintaining  the  purity  of  the  blood,  the  whole  body  (so 
to  speak)  acts  as  an  excretory  apparatus,  and  draws  into  itself  the  noxious 
substance. 

208.  There  is  a  large  number  of  cases,  moreover,  in  which,  although  the 
poisonous  or  medicinal  substances  cannot  be  traced  in  the  excretions  by  chemical 
tests,  their  effects,  when  moderate  doses  have  been  taken,  pass  off  so  completely, 
that  there  can  be  no  doubt  of  their  not  being  any  longer  present,  as  such,  in  the 
system;  and  the  substances  of  this  class  are  of  a  nature  and  composition  which 
render  them  peculiarly  susceptible  of  change,  when  subjected  to  the  influences 
which  they  will  encounter  in  the  living  body,  and  more  especially  when  exposed 
in  a  state  of  very  fine  division  to  the  agency  of  oxygen.  A  familiar  exemplifica- 
tion of  this  mode  of  elimination  of  poisons  is  furnished  by  the  transient  duration 
of  the  effects  of  a  dose  of  alcohol,  even  when  this  is  large  enough  to  produce 
insensibility;  recovery  from  them  being  merely  a  question  of  time,  provided  that 
the  state  of  torpor,  produced  by  the  action  of  this  poison  on  the  centre  of  the 

1  Such  a  perpetuation  is  seen  in  the  chronic  inflammation,  thickening,  and  contraction, 
of  the  cesophageal  walls,  consequent  upon  the  deglutition  of  strong  acids  and  caustic 
alkalies. 

2  This  has  been  shown  by  the  analyses  of  M.  Devergie  (see  the  "Traite  des  Maladies 
de  Plomb,"  of  M.  Tanquerel,  torn.  ii.  pp.  401-6),  and  of  Prof.  Miller  (see  Dr.  W.  Budd's 
essay  on  "The  Symmetry  of  Disease,"  in  the  " Medico-Chirurgical  Transactions,"  vol.  xxv. 


ITS  VITAL  PROPERTIES,  AND  RELATIONS  TO  LIVING  ORGANISM.     215 

respiratory  movements,  be  not  so  profound  as  to  occasion  Asphyxia,  or  that  death 
do  not  result  (as  sometimes  happens  when  the  poison  is  taken  in  a  state  of  con- 
centration) from  the  immediate  shock  to  the  nervous  system.  Now  the  quantity 
of  alcohol  which  passes  off  by  the  ordinary  excretions  is  extremely  slight ;  in 
fact,  this  substance  can  seldom  be  detected  in  them.  But  there  can  be  no  reason- 
able doubt  that  the  elimination  of  the  alcohol  is  due  to  its  oxidation  whilst  pass- 
ing through  the  circulating  system,  so  that  it  is  excreted  by  the  lungs  in  the 
form  of  carbonic  acid  and  water;  and  if  confirmation  of  this  view  were  needed,  it 
is  afforded  by  the  tolerance  of  large  doses  of  alcohol,  which  is  shown  when  it  is 
subjected  with  peculiar  rapidity  to  the  combustive  operation,  as  during  continued 
exposure  to  severe  cold  or  prolonged  muscular  exertion,  or  in  the  exhaustation 
of  wasting  diseases  when  no  other  combustive  material  remains  in  the  body. 
The  same  explanation  is  obviously  applicable  to  the  parallel  phenomena,  which 
present  themselves  in  the  action  of  opium,  strychnia,  prussic  acid,  &c.  With 
all  these,  also,  the  question  of  life  or  death  is  one  of  time ;  for  if  the  fatal  result 
do  not  speedily  follow  the  absorption  of  the  poison  into  the  blood,  the  patient 
gradually  recovers  from  its  effects;  and  the  most  effectual  treatment  consists  in 
the  artificial  maintenance  of  the  respiratory  movements,  which  the  influence  of 
these  poisons  upon  the  nervous  centres  might  otherwise  suspend.  These  poisons 
cannot  be  detected  in  the  circulating  fluid  by  their  sensible  or  chemical  charac- 
ters, if  a  short  interval  has  elapsed  subsequently  to  their  absorption ;  thus  it  has 
been  found  by  Dr.  Lonsdale  that  the  odor  of  prussic  acid  cannot  be  perceived  in 
the  blood  or  in  the  cavities,  when  life  had  been  prolonged  beyond  15  minutes, 
although,  when  death  took  place  within  a  shorter  time,  the  poison  might  be 
detected  in  the  body  by  its  odor  alone  for  eight  or  nine  days  afterwards;  and 
the  presence  of  morphia  ceases  to  be  recognizable  by  the  ordinary  chemical  tests, 
within  a  short  time  after  it  has  been  taken  into  the  circulating  current. — Even 
with  regard  to  certain  poisons  of  this  unstable  class,  however,  there  is  evidence 
that  they  pass  into  the  urine  and  are  thus  eliminated,  without  undergoing  any 
change  that  impairs  their  physiological  action;  this  evidence  being  afforded  by 
the  effects  of  the  reingestion  of  the  urine,  either  by  the  individuals  them- 
selves, or  by  others.  A  very  curious  example  of  this  kind  is  afforded  by  the 
intoxicating  fungus,  Amanita  muscaria,  which  is  used  by  some  of  the  inhabi- 
tants of  the  north-eastern  parts  of  Asia  in  the  same  manner  as  alcoholic  liquors 
by  other  nations.  Its  effects,  like  those  of  other  excitants,  have  a  limited  dura- 
tion; for  a  man  who  is  intoxicated  by  it  one  day,  "  sleeps  himself  sober"  by  the 
next.  His  restoration  is  due,  however,  not  to  his  repose,  but  to  the  elimination 
of  the  poison  which  takes  place  during  the  interval ;  for  if  he  drink  a  cup  of  his 
urine  the  next  morning,  he  is  yet  more  powerfully  intoxicated  than  he  was  the 
preceding  day;  and  the  fluid  has  the  same  effect  upon  any  other  individual,  into 
whose  urine  the  active  principle  then  passes;  so  that,  according  to  the  testimony 
of  travellers,  the  intoxicating  agent  may  be  transmitted  in  this  manner  through 
five  or  six  persons,  a  small  stock  at  the  commencement  thus  serving  to  maintain 
a  week's  debauch.  Results  of  the  same  order  have  been  obtained  by  Dr.  Letheby 
in  regard  to  opium,  belladonna,  hemlock,  aconite,  &c. ;  the  passage  of  these  sub- 
stances into  the  urine  being  proved  by  the  induction  of  their  characteristic  effects, 
when  that  fluid  was  administered  to  other  animals.  It  is  probable  that,  as  in 
the  case  of  lactic  acid  (§  49),  the  appearance  of  these  substances  in  the  urine  is 
due  to  their  presence  in  the  blood  in  such  quantity,  that  the  oxidizing  process  does 
not  promote  their  elimination  through  the  lungs  with  sufficient  rapidity. 

209.  Between  the  substances  which  admittedly  rank  as  poisons,  and  those 
which  are  reckoned  as  materies  morborum,  no  definite  line  of  demarcation  can 
be  drawn ;  and  the  train  of  symptoms  produced  by  the  operation  of  the  former, 
is  really  as  much  a  disease  as  that  which  results  from  the  presence  of  the  latter. 
The  connection  is,  in  fact,  established  by  those  "animal  poisons"  which  are  the 


216  OF   THE   BLOOD. 

result  of  decomposition  either  within  or  without  the  body ;  such  as  that  of  the 
"  pustule  maligne,"  or  of  the  flesh  of  animals  suffering  under  disease,  on  the 
one  hand,  or  the  a  cheese  poison/'  u  sausage  poison/'  &c.  on  the  other. — It  may 
be  admitted  that  our  belief  in  a  specific  material  cause  for  a  great  part  of  the 
effects  set  down  to  the  action  of  " morbid  poisons/'  is  merely  inferential;  and 
there  are  many  persons,  to  whom  their  exhibition  in  a  tangible  form  seems  to 
afford  the  only  convincing  evidence  of  their  existence.  But  it  must  be  remem- 
bered that  the  evidence  of  chemistry  itself  is  often  purely  inferential ;  for  we 
recognize  the  presence  of  a  chemical  substance,  not  merely  by  obtaining  it  in  a 
separate  form,  but  by  witnessing  the  reactions  which  it  displays  with  various 
tests ;  and  there  is  one  substance,  fluorine,  which  has  never  yet  been  isolated, 
and  of  whose  existence,  however,  no  chemist  would  hint  a  doubt.  Now  ifr  is 
the  human  body  which  forms  the  appropriate  testing  apparatus  of  "  morbid 
poisons;"  and  even  if  we  could  always  obtain  them  in  a  separate  state,  and 
could  subject  them  to  chemical  analysis,  we  should  know  much  less  of  their 
most  important  properties,  than  that  which  we  can  ascertain  by  observation  of 
their  actions  in  the  system;  this  alone  affording  the  means  of  judging  of  their 
dynamical  character,  which  is  of  far  more  importance  than  a  knowledge  of  their 
chemical  composition.  In  the  case  of  those  poisons  which  are  capable  of  being 
introduced  by  inoculation,  we  have  indeed,  the  required  proof  of  their  material 
existence ;  and  this  proof  is  capable  of  being  extended  by  a  safe  analogy  to 
infectious  diseases  generally.  For  if  smallpox  can  be  communicated  by  the 
inhalation  of  an  atmosphere  tainted  with  the  exhalations  of  a  person  already 
affected  with  it,  as  well  as  by  the  introduction  of  the  fluid  of  the  cutaneous  pus- 
tule into  the  blood  of  another,  it  can  scarcely  admit  of  a  question,  that  the  same 
poisonous  agent  is  transmitted  in  both  cases,  although  through  different  media, 
and  that  it  has  as  real  an  existence  in  the  transferred  air,  as  in  the  transferred 
pus.  Diseases,  then,  which  are  capable  of  being  transmitted  in  both  these 
methods,  form  the  connecting  .link  between  those  resulting  from  ordinary  toxic 
agents,  and  those  which  must  be  assumed  to  depend  upon  a  subtile  poison,  of 
which  the  air  alone  is  the  vehicle — such,  for  example,  as  malarious  fevers ;  this 
assumption  being  required  by  all  the  rules  of  logic,  as  the  only  one  which  will 
account  for  the  phenomena  to  be  explained,  and  therefore  possessing  a  claim  to 
be  accounted  an  almost  certain  truth.  There  is  a  strongly-marked  difference, 
however,  between  the  modus  operandi  of  the  toxic  agents  whose  action  has  been 
previously  examined,  and  that  of  the  morbid  poisons  we  are  now  considering ; 
for  whilst  the  former  possess  a  certain  definite  action,  the  intensity  of  which 
(cseteris  paribus)  is  proportionate  to  the  quantity  that  is  in  operation,  and  which 
is  usually  determined,  in  virtue  of  the  "  elective  affinity"  already  spoken  of,  to 
some  particular  organ  or  tissue — the  latter  act  primarily  upon  the  blood,  in- 
fluencing the  system  at  large  through  the  changes  which  they  produce  in  its 
constitution,  and  their  potency  depends  rather  upon  the  susceptibility  of  the 
blood  to  their  peculiar  influence,  than  upon  the  quantity  of  the  poison  that  may 
be  introduced  into  it. 

210.  Of  the  existence  of  such  susceptibility,  as  a  "  predisposing  cause"  of 
Zymotic1  disease,  there  cannot  be  the  slightest  doubt.  In  the  case  of  the  Ex- 
anthemata and  Hooping-cough,  we  see  that  it  is  congenital,  and  is  usually  re- 
moved by  the  occurrence  of  one  attack  of  the  disease  (although  this  is  not  a 
uniform  protection) ;  but  the  liability  even  to  these  varies  greatly  in  different 
individuals,  and  at  different  times  in  the  same  individual.  And  with  regard  to 

1  The  term  zymotic  is  a  very  convenient  designation,  which  has  of  late  gained  general 
currency,  for  that  class  of  diseases  whose  phenomena  may  be  attributed  to  the  operation 
of  a  morbid  poison  of  the  nature  described  above ;  this  operation  bearing  a  strong  analogy 
to  that  of  "ferments." 


ITS  VITAL  PROPERTIES,  AND  RELATIONS  TO  LIVING  ORGANISM.     217 

other  zymotic  diseases,  the  liability  to  which  is  not  thus  limited,  all  extended 
observation  concurs  in  showing  that  it  is  augmented  by  anything  which  tends 
to  depress  the  vital  powers  of  the  system,  and  more  particularly  by  any  cause 
which  obstructs  the  due  purification  of  the  blood,  by  the  elimination  of  the  pro- 
ducts of  decomposition.  Thus  it  will  be  shown  hereafter  (CHAP,  x.),  that  no 
antecedent  condition  has  been  found  so  efficacious  in  augmenting  the  fatality  of 
Cholera,  as  overcrowding;  which  compels  those  who  are  subjected  to  it  to  be 
constantly  breathing  an  atmosphere  not  only  charged  with  carbonic  acid,  but 
laden  with  putrescent  emanations ;  and  which  thus  favors  the  accumulation  of 
decomposing  matter  in  the  blood,  which  serves  as  the  most  appropriate  soil  for 
the  seeds  of  the  disease.  And  what  is  true  of  Cholera  has  been  found  to  be 
true  of  Zymotic  diseases  in  general ;  the  very  same  fermentable  matter  in  the 
blood  serving  for  the  development  of  almost  any  kind  of  zymotic  poison  that 
may  be  received  into  the  system,  whether  from  the  atmosphere,  or  from  the 
bodies  of  those  who  have  already  been  subjects  of  the  disease.  Now  that  what 
has  been  here  spoken  of  as  "fermentable  matter"  is  not  a  mere  hypothetical 
entity,  but  has  a  real  material  existence,  appears  from  this  consideration ;  that 
in  all  those  conditions  of  the  system  in  which  we  know  that  decomposition  is 
going  on  to  an  unusual  extent,  and  in  which  there  is  a  marked  tendency  to 
putrescence  in  the  excreted  matters,  we  witness  such  a  peculiar  liability  to  zymo- 
tic diseases,  as  clearly  indicates  that  the  state  of  the  blood  is  peculiarly  favor- 
able to  the  action  of  the  zymotic  poison.  This  is  pre-eminently  the  case  in  the 
puerperal  state,  in  which  the  tissue  of  the  uterus  is  undergoing  rapid  disinte- 
gration, its  vital  force  having  been  expended  (§  110);  for  there  is  now  abundant 
evidence,  that  the  contact  of  decomposing  matters  which  would  be  innocuous  at 
other  times,  is  capable  of  so  acting  upon  the  blood  of  the  parturient  female,  as  to 
induce  that  most  fatal  zymosis  which  is  known  as  "  puerperal  fever/'1  And 
her  peculiar  liability  is  in  no  respect  more  manifest  than  in  this;  that  the  poison 
by  which  she  is  affected  may  have  lain  dormant  for  weeks  or  months,  for  want 
of  an  appropriate  nidus,  and  will  yet  exhibit  its  full  potency  on  the  very  first 
case  in  which  opportunity  may  be  given  for  its  introduction  into  the  system  of 
a  puerperal  patient.3  The  same  kind  of  liability  is  displayed  in  the  subjects  of 
severe  injuries,  among  whom,  also,  there  is  not  only  a  depression  of  the  vital 
powers,  but  also  a  special  source  of  decomposing  matter  in  the  system ;  for  there 
is  evidence  that  "  surgical  fever"  may  be  induced  in  them  by  the  introduction 
of  a  zymotic  poison  derived  from  a  variety  of  external  sources  (amongst  others, 
from  patients  affected  with  puerperal  fever),  such  as  would  have  no  effect  upon 
a  healthy  subject;  and,  moreover,  that  overcrowding  in  hospitals  has  a  special 
tendency  to  increase  this  liability.3  So,  again,  an  excess  of  muscular  exertion, 
producing  an  unusual  "  waste"  of  tissue,  especially  when  the  elimination  of  the 
products  of  this  waste  is  interfered  with  by  imperfect  respiration,  is  well  known 
to  engender  a  peculiar  liability  to  zymotic  disease ;  and  this,  too,  finds  its  ex- 

1  For  a  most  marked  and  convincing  example  of  this  kind,  see  Dr.  Routh's  paper  on 
"The  Causes  of  the  Endemic  Puerperal  Fever  of  Vienna,"  in  the  "  Medico-Chirurgical 
Transactions,"  vol.  xxxii.  p.  27. — That  the  poison  which  develops  puerperal  fever,  may  be 
conveyed  from  patients  laboring  under  almost  any  other  form  of  Zymotic  disease  tending 
to  putrescence,  that  is  propagable  by  contact — such  as  scarlatina,  smallpox,  or  erysipelas, 
is  now  the  general  opinion  of  most  practitioners  who  have  paid  special  attention  to  the 
subject. 

2  This  is  shown  by  the  instances,  unhappily  of  no  unfrequent  occurrence,  in  which  prac- 
titioners who  have  unfortunately  become  the  vehicles  of  the  puerperal  poison,  and  have 
conveyed  it  to  several  patients  in  succession,  have  experienced  the  same  direful  results 
immediately  on  resuming  obstetric  attendance,  after  a  lengthened  interval  of  suspension 
from  it,  and  even  from  professional  employment  of  every  kind. 

3  See  Prof.  Simpson  "On  the  Analogy  between  Puerperal  and  Surgical  Fever,"  in  the 
"Edinb.  Monthly  Journ."  vol.  xi.  p.  414;  and  vol.  xiii.  p.  72. 


218  OF   THE   BLOOD. 

planation  in  the  same  principle.1  Thus,  then,  we  may  affirm  with  strong  con- 
fidence, that  the  liability  to  zymotic  disease  depends  upon  the  previous  condition 
of  the  blood ;  and  more  especially  on  the  presence  of  fermentable  matters  result- 
ing from  the  ordinary  processes  of  disintegration,  which,  in  the  state  of  perfect 
health,  are  eliminated  as  fast  as  they  are  formed,  but  of  which  an  accumulation 
is  prone  to  take  place,  either  when  there  are  special  sources  of  an  augmented 
production,  or  when  the  excretory  operations  are  imperfectly  performed.  And 
it  would  further  appear,  that  the  continued  accumulation  of  such  matters 
may  itself  become  a  source  of  certain  forms  of  Zymotic  disease,  which  may 
thus  originate  de  novo  in  the  system,  and  which  may  thence  be  propagated  to 
other  individuals  in  some  of  the  modes  already  specified;  of  this  we  have 
notable  examples  in  hydrophobia,  erysipelas,  and  the  "  pustule  maligne." 

211.  It  is  not  only,  however,  in  the  class  of  Zymotic  diseases,  that  we  seem 
distinctly  able  to  trace  the  operation  of  morbid  poisons  circulating  in  the  blood ; 
for  there  are  numerous  other  maladies,  of  whose  origin  in  a  like  condition  there 
can  be  no  reasonable  doubt;  and  these  are  in  some  respects  more  closely  analo- 
gous than  the  preceding  to  the  disordered  states  induced  by  the  introduction  of 
toxic  agents.     For  in  those  of  which  we  have  now  to  speak,  the  action  is  desti- 
tute of  any  analogy  to  fermentation,  and  its  potency  is  strictly  proportionate,  in 
each  case,  to  the  amount  of  the  dose  that  is  in  operation.     Here,  too,  we  have 
a  connecting   link  afforded  by  those  disordered  states  of  the  system,  which 
depend  upon  an  undue  accumulation  of  poisons  normally  generated  within  it, 
in  consequence  of  some  obstacle  to  their  elimination.     Thus,  the  train  of  symp- 
toms which  is  consequent  upon  the  retention  of  urea  in  the  blood,  so  much 
resembles  that  occasioned  by  the  ingestion  of  opium,  as  to  have  actually  been 
mistaken  for  it;  and  is  as  true  an  instance  of  "  poisoning,"  as  if  urea  had  been 
injected  into  the  bloodvessels.     So,  in  the  asphyxia,  which  is  produced  by  any 
obstruction  to  the  extrication  of  carbonic  acid  through  the  lungs,  the  subject  of 
it  is  as  much  "  poisoned,"  as  if  he  had  inhaled  carbonic  acid  from  without. 
Again,  the  retention  of  the  uric  acid,  biliary  matter,  lactic  acid,  and  other  sub- 
stances which  are  normal  products  of  the  waste  or  disintegration  of  the  body,  is 
capable  of  becoming  a  source  of  morbid  action  in  the  system  generally ;  and  the 
evil  is  of  course  increased,  when  (as  frequently  happens)  augmented  production 
is  concurrent  with  imperfect  elimination.     But  perversions  of  the  ordinary  dis- 
integrating processes  are  also  far  from  being  uncommon,  whereby,  instead  of  the 
substances  already  referred  to,  other  products  are  engendered,  whose  presence  in 
the  circulating  current  gives  rise  to  trains  of  symptoms  altogether  different.     Of 
this  class  we  seem  to  have  an  example  in  gout  and  rheumatism;  the  materies 
morbi  of  which  diseases,  though  probably  not  identical  with  lithic  and  lactic 
acids,  would  seem  to  be  formed  from  the  decomposing  matters  which  might  nor- 
mally have  generated  them.     There  can  be  no  doubt,  again,  that  many  chronic 
diseases  of  nutrition  are  attributable  to  a  similar  cause ;  this  being  indicated  by 
the  symmetrical  mode  in  which  they  affect  the  particular  parts  whose  condition 
is  altered  (§  201). 

212.  In  all  cases,  therefore,  one  of  the  first  questions  which  the  intelligent 
Practitioner  will  feel  called  upon  to  decide,  is,  whether  the  malady  he  has  to 
treat  have  its  origin  in  the  blood,  or  in  a  disorder  purely  local;  and,  if  he  feel 
justified  in  referring  it  to  the  blood,  whether  it  merely  depend  upon  an  alter- 
ation in  the  proportion  of  its  normal  constituents,  as  in  plethora  and  simple 
anaemia,  or  whether  its  phenomena  imply  the  presence  of  some  toxic  substance 

1  It  is  well  known  to  Indian  Medical  Officers,  that  the  liability  to  Fever,  Dysentery, 
Cholera,  &c.,  is  very  much  increased  during,  and  for  some  time  after,  a  severe  march.  For 
a  very  striking  example  of  the  influence  of  this  condition,  concurrently  with  overcrowding, 
in  producing  a  terrible  augmentation  in  the  fatality  of  Cholera,  see  "Brit,  and  For.  Med. 
Chir.  Rev."  vol.  ii.  pp.  80-90. 


ITS  VITAL  PROPERTIES,  AND  RELATIONS  TO  LIVING  ORGANISM.     219 

in  the  circulating  fluid. — If  the  former  be,  his  conclusion,  he  has  then  to  endea- 
vor to  rectify  the  excess  or  the  deficiency,  by  reducing  the  former,  or  by  supply- 
ing the  latter;  as  when  he  bleeds  and  prescribes  low  diet  for  plethora,  and 
employs  iron  and  generous  living  in  anaemia.  But  it  is  his  duty  to  take  care 
that  his  means  are  appropriate  to  his  ends;  and  especially  to  abstain,  when 
endeavoring  to  draw  off  an  excess  of  one  constituent,  from  doing  serious  injury 
by  reducing  another  which  may  be  already  below  par,  and  of  which  the  pres- 
ence may  be  essential  to  enable  the  system  to  resist  the  further  progress  of  the 
malady.  Thus,  as  we  have  seen,  bloodletting  has  no  decided  effect  in  lowering 
the  proportion  of  fibrin  in  the  blood,  whilst  it  has  a  most  direct  influence  in  re- 
ducing the  number  of  red  corpuscles ;  and  there  can  be  little  doubt  that  the  too 
copious  venesection  which  was  formerly  practised  almost  indiscriminately  in 
acute  inflammations,  had  a  most  decided  influence  in  postponing  the  final  reco- 
very from  them,  whilst  it  had  often  but  a  doubtful  efficacy  in  subduing  the 
first  violence  of  the  disease.  As  a  general  rule  it  may  be  stated,  that  general 
bloodletting  is  likely  to  be  rather  injurious  than  beneficial  in  toxic  inflamma- 
tions, in  which  the  vitality  of  the  blood  as  a  whole  is  decidedly  lowered,  not- 
withstanding the  large  increase  in  the  proportion  of  fibrin ;  and  to  this  rule  the 
results  of  careful  and  extended  observation  have  recently  shown  that  Rheuma- 
tism is  seldom  to  be  considered  an  exception,  notwithstanding  that  this  disease 
was  formerly  considered  to  be  one  of  those  in  which  the  efficacy  of  copious 
depletion  was  most  undoubted. — In  diseases  of  toxic  origin,  the  treatment  must 
be  conducted  upon  principles  exactly  the  same  as  those  by  which  the  practitioner 
would  be  guided  in  his  treatment  of  a  case  of  ordinary  poisoning ;  but  as  regards 
the  two  classes  into  which  it  has  been  shown  that  these  maladies  may  be  divided, 
a  difference  must  be  made  in  their  application. 

213.  The  "morbid  poisons"  of  our  second  class  (§  211)  are  distinguished  by 
this,  that  there  is  a  continual  new  generation  of  them  within  the  system ;  and 
the  first  indication  of  treatment,  therefore,  will  be  to  check  their  formation,  so 
far  as  this  may  be  possible.     This  is  the  rationale  of  the  dietetic  and  regiminal 
treatment  of  the  lithic,  lactic,  and  oxalic  diatheses,  of  lepra  and  psoriasis,  of 
chronic  gout  and  rheumatism,  and  many  other  chronic  diseases  of  toxic  origin. 
Secondly,  we  should  endeavor  to  destroy  or  neutralize  the  poison,  if  we  have 
any  remedies  which  possess  such  an  action  upon  it.     Perhaps  the  curative  in- 
fluence of  arsenic  in  some  of  the  chronic  skin  diseases,  is  one  of  the  best  ex- 
amples of  this  kind ;  but  it  must  be  admitted  that  such  direct  "  antidotes"  to 
morbid  poisons  are  very  few  in  number.     Thirdly,  where  we  cannot  thus  destroy 
the  poison,  we  must  endeavor  to  moderate  its  action  upon  the  system ;  this  is 
the  rationale  of  palliative  treatment  of  every  description,  in  which  the  fans  et 
origo  of  the  malady  is  left  unchanged. — But  fourthly,  our  main  object  must  be 
to  eliminate  the  poison  from  the  system  as  rapidly  as  possible,  by  the  various 
channels  of  excretion ;  acting  upon  these  by  remedies  which  will  increase  their 
activity,  or  which  will  so  alter  the  condition  of  the  morbific  matter,  as  to  enable 
it  to  be  more  readily  drawn  off.     The  judgment  of  the  well-informed  practitioner, 
in  the  treatment  of  diseases  of  this  class,  is  more  shown  in  his  discriminative 
selection  of  the  best  means  of  thus  aiding  the  Blood  to  regain  its  normal  purity, 
than  in  any  more  apparently  "  heroic  measures ;"  and  a  candid  review  of  the 
most  approved  systems  of  treatment  for  disease  of  the  type  here  alluded  to,  will 
show  that  the  ratio  of  their  efficacy  is  in  accordance  with  that  of  their  harmony 
with  the  above  indications. 

214.  In  the  toxic  diseases  of  the  zymotic  class,  in  most  of  which  the  poison 
is  introduced  from  without,  the  course  of  the  morbid  phenomena  to  which  it 
gives  rise  is  usually  more  definite  and  specific,  and  its  duration  more  limited. 
There  is  no  source  within  the  system  whence  a  new  supply  of  the  poison  is 
continually  arising ;  and  its  operation  ceases,  therefore,  as  soon  as  it  is  entirely 


220  OF   THE   BLOOD. 

eliminated  from  the  system.  But  there  is  this  peculiarity  in  the  action  of  many 
of  the  poisons  in  question,  that  they  have  the  power  of  multiplying  themselves 
within  the  body ;  thus,  for  example,  when  smallpox  has  been  communicated  by 
the  inoculation  of  an  excessively  minute  portion  of  the  virus,  hundreds  or 
thousands  of  pustules  are  generated,  each  of  them  charged  with  a  poison  equally 
potent  with  that  from  which  they  originated.  It  is  to  this  multiplication,  that 
the  extension  of  zymotic  diseases,  by  communication  between  individuals  affected 
with  them  and  healthy  subjects,  is  chiefly  due ;  and  the  question  of  the  "  con- 
tagion" or  "non-contagion"  of  any  particular  disease  of  this  class,  is,  therefore, 
essentially  that  of  the  multiplication  or  non-multiplication  of  the  poison  in  the 
human  body.  This  multiplication  of  certain  zymotic  poisons  is  a  yet  stronger 
point  of  analogy  to  the  action  of  ferments,  than  that  which  is  afforded  by  the 
violence  of  the  changes  they  induce,  when  compared  with  the  amount  in  opera- 
tion. Some  of  these  poisons  are  of  such  potency  that,  in  however  minute  a 
quantity  they  are  introduced,  they  will  change  the  whole  mass  of  the  blood  in  a 
few  minutes;  and  will  act  indiscriminately  on  all  individuals  alike;  this  is  the 
case,  for  example,  with  the  venom  of  serpents.  On  the  other  hand,  there  are 
many  (as  already  remarked)  which  seem  to  require  the  presence  of  some  special 
fermentable  matter  in  the  blood  (§  210).  And  between  these  might  probably 
be  established  a  regular  gradation — from  those  most  "  pernicious'7  forms  of 
malarious  poison  which  derive  their  potency  from  the  intensity  of  vegetable  de- 
composition under  the  influence  of  a  high  temperature,  and  those  "  malignant" 
types  of  typhoid  poison  which  owe  their  special  intensity  to  animal  putrescence 
engendered  by  filth  and  overcrowding,  both  of  these  attacking  a  very  large  pro- 
portion of  those  who  are  exposed  to  them — to  those  milder  forms  of  zymotic 
poisons,  which,  though  derived  from  the  same  sources  with  the  preceding,  act 
with  so  much  less  of  uniformity  upon  different  individuals,  that  we  can  scarcely 
fail  to  recognize,  as  a  "  predisposing  cause,"  or  rather  as  a  necessary  concurrent 
condition,  the  presence  of  some  readily-decomposable  matter  in  the  blood.  The 
long-continued  action  of  these  poisons,  in  their  milder  forms,  seems  itself  capable 
of  inducing  this  condition;  thus,  a  healthy  person  who  settles  in  an  aguish 
country,  may  remain  free  from  intermittent  fever  for  a  considerable  time,  but 
his  health  gradually  deteriorates,  and  at  last  he  becomes  the  subject  of  the  dis- 
ease, which  would  have  much  earlier  attacked  him  if  his  blood  had  been  brought 
into  the  a  fermentable"  state  by  irregularity  of  diet,  over-exertion,  &c.;  and  the 
same  may  be  observed  in  the  case  of  those  long  exposed  to  the  poison  of  typhoid 
or  other  fevers,  which  especially  locates  itself  in  animal  miasmata,  if  not  actually 
engendered  by  them. 

215.  In  some  of  the  diseases  of  this  class,  the  change  in  the  qualities  of  the 
blood  produced  by  the  introduction  of  the  poison,  is  such  as  to  give  it  a  morbid 
action  on  certain  organs  or  tissues  only;  their  phenomena  in  this  respect  cor- 
responding with  those  of  ordinary  poisons,  and  of  the  toxic  diseases  previously 
noticed.  Such  may  be  said  of  hydrophobia,  vaccinia,  gonorrhoea,  primary 
syphilis,  &c.,  in  which  the  general  functions  of  the  body  are  disturbed  chiefly 
or  solely  through  the  local  disorder.  But,  in  other  cases,  we  find  that  the  con- 
tamination of  the  blood  is  such  as  to  produce  more  or  less  disturbance  in  all  the 
functions;  as  we  especially  witness  in  the  severer  forms  of  fever,  in  poisoning 
by  venomous  serpents,  &c.  Even  in  this  last  class  of  cases,  however,  a  special 
determination  to  one  organ  or  system  is  frequently  obvious;  and  this  may  either 
be  so  constant  as  to  be  characteristic  of  the  disease,  which  is  the  case  with  the 
skin  affection  in  the  Exanthemata ;  or  it  may  be  chiefly  directed  by  the  previous 
condition  of  the  patient's  system,  that  organ  or  tissue  (amongst  those  on  which 
the  poison  is  capable  of  acting)  being  most  affected  whose  previous  nutrition  was 
least  healthy,  as  appears  in  the  variety  of  local  affections  that  are  developed 
during  an  epidemic  Influenza.  This  local  determination  may  frequently  be 


ITS  VITAL  PROPERTIES,  AND  RELATIONS  TO  LIVING  ORGANISM.      221 

regarded  as  one  of  the  means  whereby  the  blood  and  the  system  at  large  are 
freed  from  the  action  of  the  poison ;  of  this  we  have  a  most  characteristic  ex- 
ample in  the  Exanthemata.  For  it  is  a  matter  of  constant  observation,  that 
constitutional  symptoms,  especially  the  fever  and  delirium,  are  most  severe  before 
the  cutaneous  eruption  comes  out ;  that  there  is  much  greater  danger  to  life, 
when  the  eruption  does  not  develop  itself  fully;  and  that  its  premature  repres- 
sion induces  a  return  of  the  severer  constitutional  affection.  It  may  be  objected 
to  this  general  statement,  that,  as  the  severity  of  smallpox  usually  bears  a  con- 
stant ratio  to  the  amount  of  the  cutaneous  eruption,  this  cannot  be  regarded  as 
relieving  the  blood  of  a  poisonous  impregnation;  but  it  is  to  be  borne  in  mind, 
on  the  one  hand,  that  the  confluence  of  the  pustules  greatly  impedes  the  normal 
functions  of  the  skin,  whereby  the  constitutional  disturbance  is  most  seriously 
aggravated,  their  suspension,  if  complete,  being  itself  adequate  to  destroy  life; 
and  besides  this,  the  excessive  development  of  the  eruption  is  an  indication  that 
the  poison  has  either  possessed  an  extraordinary  potency,  or  has  found  within 
the  blood  a  material  peculiarly  favorable  for  its  development.  A  similar  ex- 
ample of  a  local  affection,  apparently  originating  in  an  eliminative  determi- 
nation of  the  poison  to  a  particular  organ,  but  sometimes  increasing  to  such  an 
extent  as  itself  to  become  a  serious  and  even  fatal  lesion,  is  afforded  by  the 
inflammation  and  ulceration  of  the  Peyerian  glandulee  in  various  zymotic  dis- 
eases.1 

216.  In  nearly  all  the  toxic  diseases  of  this  class,  there  is  a  natural  tendency 
to  the  self-elimination  of  the  poison  and  of  the  products  of  its  action  on  the 
blood,  either  by  the  operation  of  the  ordinary  excretory  organs,  or  by  the  pecu- 
liar local  actions  just  adverted  to;  and  this  process  takes  place  in  many  instances 
with  such  regularity,  that  the  time  which  it  will  require  may  be  almost  exactly 
predicted.  There  is  not,  in  fact,  a  more  remarkable  indication  of  the  "  Life  of 
the  Blood/7  than  is  afforded  by  its  extraordinary  power  of  self-recovery,  after 
having  undergone  the  excessive  perversion  which  is  consequent  upon  the  intro- 
duction of  the  more  potent  zymotic  poisons;  and  every  philosophical  physician 
is  ready  to  admit,  that  it  is  to  this  "vis  medicatrix  naturae/'  rather  than  to  any 
remedial  agency  which  it  is  in  his  power  to  apply,  that  he  must  look  for  the 
restoration  of  his  patient.  The  very  nature  of  the  action  of  zymotic  poisons 
upon  the  blood,  seems  to  forbid  the  expectation  of  our  being  able  to  neutralize 
or  check  that  action  by  antidotes;  and  the  objects  of  treatment  wholly  lie, 
therefore,  in  promoting  the  elimination  of  the  morbific  matters  thus  engendered, 
in  keeping  under  any  dangerous  excess  of  local  action,  and  in  supporting  the 
system  during  the  continuance  of  the  malady.  In  a  large  proportion  of  zymotic 
diseases,  it  is  probable  that  the  oxidation  of  the  morbific  matter  by  the  aeration 
of  the  blood,  is  the  chief  means  of  its  removal;  and  it  is  accordant  with  this 
view,  that  the  encouragement  of  the  respiratory  function,  both  pulmonary  and 
cutaneous,  by  a  pure  and  cool  atmosphere,  and  by  keeping  the  skin  moist  (either 
by  the  administration  of  diaphoretic  medicines  or  by  external  applications)  should 
be  found  one  of  the  most  efficient  means  of  promoting  recovery.2  Whilst  mild 
purgatives  may  be  employed  with  advantage  for  the  same  end,  in  the  earlier 
stages  of  these  diseases,  care  must  be  taken  that  the  system  be  not  too  much 
debilitated  by  their  action ;  and  the  same  caution  must  be  observed  with  regard 
to  the  use  of  local  depletion  or  counter-irritation,  for  the  purpose  of  subduing 

1  See  Dr.  Williams' s  "Principles  of  Medicine,"  p.  279,  Am.  Ed. 

2  Dr.  Daniell,  whose  long  familiarity  with  the  most  pernicious  forms  of  African  fever, 
and  with  the  various  modes  of  treatment  which  have  been  put  in  practice  for  its  cure, 
gives  a  most  decided  preference  to  the  sudorific  system  in  vogue  among  the  natives,  as 
having  a  vast  superiority  over  the  venesections,  saline  purgatives,  and  large  doses  of  calo- 


mel, which  most  European  practitioners  have  employed.     See  his  "Sketches  of  the  Medi- 
cal Topography  of  Native  Dis 


iseases  of  the  Gulf  of  Guinea,"  p.  120. 


222  OF   THE    PRIMARY   TISSUES    OF   THE    HUMAN   BODY. 

the  violence  of  some  local  affection.  In  fact,  the  general  tendency  of  these 
diseases  to  the  adynamic  type,  seems  to  indicate  that,  however  beneficial  the 
immediate  results  of  reducing  treatment  may  appear  to  be,  its  remote  effects  are 
much  to  be  dreaded.  And  when  the  results  of  a  large  and  varied  experience 
are  brought  together,  the  Author  believes  that  those  will  be  found  most  satis- 
factory in  which  the  treatment  has  been  moderately  evacuant  and  early  susten- 
tative.1 


CHAPTER  Y. 

OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN  BODY;    THEIR 
STRUCTURE,    COMPOSITION,   AND   ACTIONS. 

217.  THE  elementary  Cells,  Membranes,  and  Fibres,  of  which  a  general 
description  has  been  given  in  a  preceding  chapter,  are  combined  with  each  other 
in  various  modes,  and  are  subjected  to  various  metamorphoses,  to  form  those 
different  types  of  Organic  Structure,  to  which  the  name  of  Primary  Tissues  is 
given.  These  may  be  seen  to  evolve  themselves  gradually  from  that  homoge- 
neous mass  of  cells,  of  which  the  fabric  of  the  embryo  is  originally  composed ; 
each  tissue  becoming  more  unlike  the  rest  in  structure  and  properties,  as  it 
advances  in  its  development;  but  yet  presenting,  even  in  its  most  complete  and 
perfected  state,  no  endowments  which  are  not  referable  to  those  of  the  simple 
primordial  cells  from  which  it  originated.  By  this  developmental  process,  in 
fact,  a  structure  is  formed,  in  which  every  separate  part  has  a  distinct  office  to 
perform;  and  it  is  this  complete  "specialization,"  or  "division  of  labor,"  which 
constitutes  the  highest  degree  of  organization.  In  every  such  fabric,  however, 
each  part  lives,  not  only  for  itself,  but  also  for  every  other  part;  for  this  very 
specialization,  whilst  it  involves  the  increase  of  some  particular  form  of  vital 
endowment,  involves  also  the  decrease  of  others  (§  113);  and  hence  it  comes 
to  pass,  that  the  sum  of  the  operations  necessary  for  the  maintenance  of  the 
life  of  even  a  single  cell,  in  the  conditions  amidst  which  Man  is  placed,  can  only 
be  performed  by  the  totality  of  his  entire  organism,  all  the  parts  of  which  are 
mutually  dependent  upon  one  another.  Thus,  the  life  of  his  Nervo-Muscular 
apparatus,  which  may  be  considered  as  the  most  essential  part  of  his  fabric, 
cannot  be  sustained  except  by  nutritive  material  prepared  and  conveyed  to  it  by 
the  organs  of  Digestion  and  Circulation,  and  would  soon  cease  if  provision  were 
not  also  made  for  conveying  away  the  products  of  its  disintegration,  by  the 
various  instruments  of  Excretion;  whilst,  on  the  other  hand,  the  appropriation, 
preparation,  and  ingestion  of  food,  the  sustenance  of  the  respiratory  changes, 
and  many  other  actions  essential  to  the  preparation  and  purification  of  the 
pabulum  of  the  Nervo-Muscular  apparatus,  require  the  assistance  of  movements 
which  it  alone  is  competent  to  execute. — As  the  properties  which  the  Primary 
Tissues  possess  in  common  have  been  already  considered  (CHAP,  in.),  we  have 
now  to  inquire  into  those  by  which  they  are  severally  distinguished ;  and  to 
trace  out,  so  far  as  may  be,  the  mode  in  which  their  special  types  of  structure 
and  endowment  are  respectively  evolved,  from  those  more  general  forms  in  which 
they  all  originate. 

1  On  the  subject  of  the  latter  portion  of  this  section,  the  treatise  of  the  late  Dr.  Robert 
Williams  on  "Morbid  Poisons,"  and  the  "Principles  of  Medicine,"  of  Dr.  Charles  J.  B. 
Williams,  may  be  studied  with  great  advantage. 


THEIR   STRUCTURE,    COMPOSITION,    AND   ACTIONS.  223 

218.  In  a  purely  anatomical  classification,  the  order  in  which  these  Tissues 
would  be  most  appropriately  arranged,  would  doubtless  be  that  of  their  relation 
to  the  primitive  types  already  described;  but  such  a  classification,  strictly 
followed  out,  would  involve  so  many  physiological  incongruities,  as  to  render  it 
unsuitable  to  our  present  purpose.  For  the  particular  office  which  each  tissue 
performs  in  the  vital  economy,  depends,  not  upon  its  own  structure  and  endow- 
ments alone,  but  upon  its  position  in  reference  to  that  of  others;  and  thus,  if  we 
grouped  together  all  the  tissues  consisting  of  unaltered  cells,  we  should  find  a 
certain  set  adapted  to  introduce  nourishment  into  the  blood  from  the  contents 
of  the  alimentary  canal,  in  virtue  of  their  position,  and  of  their  inherent  power 
of  selection  and  appropriation;  whilst  another  set,  drawing  a  similar  material 
out  of  the  blood,  converts  it  into  a  portion  of  the  solid  fabric;  and  a  third,  by 
the  exercise  of  the  very  same  powers,  removes  from  the  circulating  fluid  the 
final  products  of  the  retrograde  metamorphosis  of  the  histogenetic  substances, 
and  pours  them  back  (it  may  be)  into  the  very  cavity  from  which  those  sub- 
stances were  originally  drawn.  If,  on  the  other  hand,  we  were  to  consider 
these  Tissues  in  their  physiological  aspect  only,  as  the  instruments  of  so  many 
distinct  classes  of  operations,  which  all  concur  in  the  maintenance  of  the  general 
life  of  the  organism,  we  might  be  led  to  attach  too  little  importance  to  their 
fundamental  relations  to  each  other  and  to  the  primitive  forms  out  of  which 
they  are  developed.  Hence  it  will  be  advisable,  in  this  as  in  a  former  instance 
(CHAP,  ii.),  to  adopt  a  mixed  classification,  which  may,  so  far  as  practicable, 
serve  both  purposes;  and  the  Primary  Tissues  of  the  Human  Body  will  be 
arranged,  therefore,  under  the  following  heads. 

I.  The  Simple  Fibrous  Tissues,  including  the  elementary  forms  known  as 
the  "white"  and  "yellow"  fibrous  tissues,  and  the  various  combinations  and 
arrangements  of  these,  which  are  known  as  Areolar  or  "  connective"  tissue, 
Tendons,  Ligaments,  Aponeuroses,  &c.;  all  serving  purposes  of  a  purely  mecha- 
nical nature. 

ii.  The  Fibro-  Cellular  Membranes,  which  are  composite  structures,  made  up 
of  textures  formed  by  interwoven  fibres,  of  simple  basement-membrane  covering 
the  surface  of  these,  and  of  one  or  more  layers  of  cells  upon  the  free  surface 
of  the  basement-membrane ;  such  are  the  Skin  investing  the  exterior  of  the 
body,  the  Mucous  Membranes  which  are  prolonged  from  the  skin  through  all  its 
open  cavities,  and  the  Serous  and  Synovial  Membranes  which  line  the  closed 
cavities.  With  the  Skin  it  will  obviously  be  proper  to  consider  the  "epidermic 
appendages,"  namely,  the  Hair  and  Nails;  whilst  with  the  Mucous  Membranes, 
the  Glandular  apparatus  is  no  less  naturally  connected. 

in.  Those  purely  Cellular  Tissues,  which  form  part  of  the  interior  fabric; 
of  these,  the  Adipose  and  the  Cartilaginous  are  the  types. 

iv.  The  "sclerous"  tissues,  Bones  and  Teeth,  which  are  composed  of  an 
animal  basis  that  is  partly  fibrous,  partly  cellular,  consolidated  by  calcareous 
deposit. 

V.  The  Tubular  Tissues,  which  serve  for  the  conveyance  of  liquids  through 
the  other  tissues;  namely,  the  Bloodvessels  and  Absorbents. 

VI.  The  Muscular  Tissue,  which  is  especially  distinguished  by  its  contractile 
power;  one  form  of  it  being  composed  of  elongated  primitive  cells,  the  other  of 
parent-cells  elongated  or  coalesced  into  tubes,  within  which  are  aggregations  of 
minute  secondary  cells. 

vn.  The  Nervous  Tissue,  which,  like  the  preceding,  is  rather  distinguished 
by  its  vital  endowments  than  by  the  peculiarity  of  its  organic  structure ;  for  it 
partly  consists  of  simple  cells,  whilst  another  part  of  it  is  formed  by  cells  elon- 
gated or  coalesced  into  tubes. 


224  OF   THE   PRIMARY   TISSUES    OF   THE    HUMAN    BODY. 


1.    Of  ike  Simple  Fibrous  Tissues. 

219.  The  various  components  of  the  Vegetable  fabric — its  cells,  tubes,  woody 
fibres  (or  elongated  cells),  &c.,  being  destined  to  retain  their  relative  situations 
throughout  their  entire  existence,  are  held  together  by  simple  adhesion;  a  gummy 
intercellular  substance,  which  answers  the  purpose  of  a  cement,  being  often  in- 
terposed, sometimes  in  considerable  quantity.     But  in  the  Animal  body,  of 
which  the  several  parts  are  designed  to  move  with  greater  or  less  freedom  upon 
one  another,  the  aggregations  of  cells  that  make  up  its  chief  part,  either  in 
their  original  or  in  their  metamorphic  form,  could  not  be  held  together  in  their 
constantly-varying  relative  positions,  without  some  intervening  substance  of  an 
altogether  different  character.     It  must  be  capable  of  resisting  tension  with  con- 
siderable firmness  and  elasticity;  it  must  admit  free  movement  of  the  several 
parts  upon  one  another;  and  it  must  still  hold  them  sufficiently  close  together, 
to  resist  any  injurious  strain  upon  the  delicate  vessels,  nerves,  &c.,  which  pass 
from  one  to  another,  as  well  as  to  prevent  any  permanent  displacement.     Now 
all  these  offices  are  performed  in  a  remarkably  complete  degree,  by  the  Areolar 
Tissue  (§  222);  the  reason  of  whose  restriction  to  the  Animal  kingdom  is  thus 
evident.     And  as  necessity  arises,  in  certain  parts,  for  tissues  which  shall  exer- 
cise a  still  greater  power  of  resistance  to  tension,  and  which  shall  thus  commu- 
nicate motion  (as  in  the  case  of  Tendons),  or  shall  bind  together  organs  that 
require  to  be  united  (as  in  the  case  of  Ligaments  and  Fibrous  Membranes),  so 
do  we  find  peculiar  tissues  developed,  that  serve  these  purposes  in  the  most 
effectual  manner.     Hence  these  tissues,  also,  although  not  endowed  with  any 
properties  that  are  peculiarly  animal,  are  nevertheless  restricted  to  the  Animal 
Kingdom — as  completely  as  are  the  Muscular  and  Nervous  Tissues,  which  make 
up  the  essential  parts  of  the  apparatus  of  Animal  Life. 

220.  These  two  qualities — that  of  resistance  to  tension  without  any  yielding 
— and  that  of  resistance  combined  with  elasticity — are  characteristic  of  two  dis- 
tinct forms  of  Fibrous  tissue;  and  these  are  distin- 
guished  by  the  hue  which  they  ordinarily  present, 
as  the  White  and  the  Yellow. — The  White  presents 
itself  in  the  form  of  inelastic  bands  of  variable 
size,  the  largest  l-500th  of  an  inch  in  breadth, 
somewhat  wavy  in  their  direction,  and  marked 
longitudinally  by  numerous  streaks  (Fig.   18); 
these  streaks  are  rather  the  indications  of  a  longitu- 
dinal creasing,  than  a  true  separation  into  compo- 
nent fibres ;  for  it  is  impossible  by  any  art  to  tear 
up  the  band  into  filaments  of  a  determinate  size, 
although  it  manifests  a  decided  tendency  to  tear 
lengthwise.     Sometimes,  however,  distinct  fibres 

may  ke  Braced,  whose  diameter  varies  from  about 

Ligamen .     l-15,000th   to   l-20,000th   of  an   inch.  — This 
Magnified  65  diameters.  tissue  is  entirely  resolved  into  Gelatin  (§  33)  by 

sufficiently  prolonged  boiling.  When  treated 
with  Acetic  acid  under  the  microscope,  it  swells  up  and  becomes  transparent ; 
and  certain  oval  corpuscles  are  then  brought  into  view,  which  seem  to  be  either 
the  nuclei  of  the  cells  that  were  concerned  in  the  formation  of  this  tissue,  or 
the  free  nuclei  of  the  blastema  by  whose  fibrillation  it  was  produced  (§§  223, 
224). — This  tissue  is  nearly  the  sole  component  of  Tendons,  Ligaments,  Fibrous 
Membranes,  Aponeuroses,  &c.,  all  of  which  present  the  arrangement  already 
described,  with  very  little  modification,  save  that  the  bands  are  often  but  slightly 
wavy,  and  are  sometimes  even  quite  straight.  If  the  traction  to  be  resisted 


OF   THE    SIMPLE   FIBROUS   TISSUES. 


225 


Fig.  19. 


should  be  applicable  in  one  direction  only,  as  is  the  case  in  Tendons  and  in  most 
Ligaments,  we  find  the  bands  or  fasciculi  of  fibres  arranged  side  by  side  with 
considerable  regularity;  and  the  larger  tendons  are  shown  by  transverse  section 
to  be  made  up  of  numerous  aggregations  of  this  kind,  which  are  held  together, 
whilst  to  a  certain  degree  kept  apart  from  one  another,  by  the  interposition  of 
Areolar  tissue.  When,  however,  the  traction  is  liable  to  be  exercised  in  various 
directions,  the  fasciculi  of  primitive  fibres  are  observed  to  cross  each  other 
obliquely;  this  decussation  is  observable  in  many  ligaments,  but  still  more  in 
those  fibrous  structures  which  serve  as  protective  capsules  to  softer  organs. 
This  tissue  receives  very  few  bloodvessels,  and  still  fewer  nerves;  indeed,  it 
seems  doubtful  whether,  in  many  fibrous  structures  (as  tendons),  nerves  are 
normally  present  at  all,  except  on  the  sheaths  of  the  bloodvessels.  From  the 
time  when  it  has  attained  its  complete  development,  this  tissue  seems  entirely 
destitute  of  any  vital  endowment,  and  its  physical  actions  are  not  of  a  kind  to 
induce  disintegrating  changes  in  its  substance,  with  any  considerable  degree  of 
rapidity.  Hence,  although  it  is  very  rapidly  regenerated  by  the  formative 
powers  of  the  blood,  after  the  destruction  of  a  portion  of  it  by  disease  or 
accident  (§  224),  it  does  not  seem  to  undergo  much  interstitial  change  during 
the  ordinary  performance  of  its  functions. 

221.  The  Yellow  fibrous  tissue  (Fig.  19)  exists  in  the  form  of  cylindrical 
fibres,  easily  separable  from  each  other  longitudinally,  except  when  they  branch 
and  inosculate ;  they  have  a  dark  decided  border ;  and  their  usual  diameter, 
in  the  tissues  of  which  they  are  the  principal  components,  is  about  l-7500th  of 
an  inch,  though  they  are  sometimes 
nearly  double,  and  sometimes  scarcely 
one  quarter  of  that  thickness.  One  of 
their  most  marked  peculiarities  is 
their  tendency  to  break  off  abruptly, 
the  broken  ends  curling  back  upon 
themselves ;  and  this  suggests  the  idea 
that  they  are  composed  of  linear  aggre- 
gations of  particles  of  a  very  definite 
character.1  The  composition  of  this 
tissue  is  very  different  from  that  of  the 
white  ;  for  it  is  but  little  changed  by 
long  boiling ;  and  although  the  decoc- 
tion slightly  gelatinizes  on  cooling, 
yet  the  small  amount  of  gelatin  thus 
indicated  is  probably  derived  from  the 

white  fibrous  element  of  the  areolar  tissue,  with  which  the  elastic  tissue  is 
usually  penetrated.  It  is  unaffected  by  the  weaker  acids,  and  undergoes  no 
solution  in  the  gastric  fluid;  and  it  preserves  its  elasticity  for  an  almost 
unlimited  period.  According  to  Scherer,  the  yellow  fibrous  tissue  from  the 
middle  coat  of  the  arteries  consists  of  480,  38H,  6N,  160 ;  which  (taking 
Liebig's  formula  for  Protein)  may  be  regarded  as  1  Protein +2  Water.  When 
burned,  it  leaves  1.7  per  cent,  of  ash.  It  is  always  readily  distinguished  from 
the  white  fibrous  tissue,  under  the  microscope,  by  its  complete  resistance  to 
acetic  acid.  There  is  less  tendency  to  spontaneous  decomposition  in  this  tissue, 
than  in  any  other  of  the  soft  and  moist  portions  of  the  fabric.  It  requires  but 

1  In  the  ligamentum  nuchae  of  the  Giraffe,  indeed,  the  fibres  are  marked  with  peculiar 
transverse  striations,  strongly  resembling  those  of  the  hairs  of  the  Mouse  and  other 
Rodents,  and,  as  in  them,  probably  indicative  of  a  cellular  organization.  (See  Mr. 
Quekett's  "  Catalogue  of  the  Histological  Series  contained  in  the  Museum  of  the  Royal 
College  of  Surgeons  of  England,"  vol.  i.  pi.  v.  fig.  10.) 

15 


Yellow  Fibrous  Tissue,  from  Ligamentum  Nuchse  of 
Calf.    Magnified  65  diameters. 


226.  OF   THE   PRIMARY   TISSUES   OF   THE    HUMAN   BODY. 

little  renovation,  therefore,  by  the  nutritive  operations ;  since  it  seems  to  pos- 
sess no  further  vital  activity  when  once  it  is  fully  developed,  and  the  exercise 
of  its  physical  properties  will  involve  but  little  disintegration.  Accordingly,  it 
is  but  very  sparingly  supplied  with  bloodvessels,  and  no  nerves  have  been 
traced  into  its  substance. — This  tissue  makes  up  the  principal  part  of  the  Liga- 
menta  sub-flava,  which  extend  between  the  arches  of  the  adjacent  vertebrae, 
connecting  them  together,  but  still  allowing  them  considerable  "play;"  it  also 
forms  a  large  portion  of  the  middle  or  fibrous  coat  of  the  Arteries ;  and  the 
Chordae  vocales,  and  some  other  ligaments  of  the  larynx,  are  almost  entirely 
composed  of  it.  In  all  these  situations,  elasticity  is  the  property  which  is  par- 
ticularly required ;  and  the  structures  enumerated  are  among  the  most  elastic 
of  all  known  substances,  recovering  this  attribute  upon  being  moistened,  after 
having  been  kept  in  a  dried  state  for  an  unlimited  period. 

222.  A  very  large  proportion  of  the  body,  in  Man  as  in  all  the  higher  Ani- 
mals, is  composed  of  a  tissue,  to  which  the  name  of  "  cellular"  was  formerly 

given.  This  term,  however,  is  so  much  more 
applicable  to  those  structures  which  are  com- 
posed of  a  congeries  of  distinct  cells,  and  the  use 
of  it  for  both  purposes  is  so  likely  to  engender 
confusion,  that  it  is  to  be  wished  that  its  appli- 
cation to  this  texture  should  be  altogether  dis- 
continued.— The  tissue  in  question,  now  gene- 
rally designated  the  Areolar ',  is  found,  when 
examined  under  the  Microscope,  to  consist  of  a 
network  of  minute  fibres  and  bands,  interwoven 
in  every  direction  (Fig.  20),  so  as  to  leave  in- 
numerable interstices,  which  communicate 
freely  with  each  other.  These  fibres  and  bands 

Arrangement  of  Fibres  in  Areolar  Tissue.       are  Composed  in  part  of  the  White  and  in  part 

Magnified  135  diameters.  of  the  Yellow  fibrous  element  (Fig.  21);  and 

the  proportion  of  the  two  varies  with  the  degree 

of  elasticity  which  may  be  required  for  the  special  purpose  which  the  tissue  is 
destined  to  serve  in  each  situation.1  The  proportion  between  them  is  easily 
determined  by  the  use  of  acetic  acid,  which  renders  the  white  so  transparent  as 
to  be  invisible,  and  thus  brings  the  yellow  into  full  distinctness.  Sometimes  the 
elastic  fibres  are  observed,  not  merely  to  interlace  with  the  white,  but  to  pass  round 
their  fasciculi,  constricting  them  with  distinct  rings  or  with  a  continuous  spiral; 
this  remarkable  disposition  is  best  seen  in  the  areolar  tissue  that  accompanies 
the  arteries  at  the  base  of  the  brain.  This  tissue  yields  gelatin  on  boiling,  in 
virtue  of  the  White  fibrous  structure  of  which  it  is  chiefly  composed.  Its  inter- 
stices are  filled  during  life  with  a  fluid,  which  resembles  a  very  dilute  Serum 
of  the  blood;  it  consists  chiefly  of  water,  but  contains  a  sensible  quantity  of 
common  salt  and  albumen,  and  (when  concentrated)  a  trace  of  alkali  sufficient 
to  affect  test-paper.  The  presence  of  this  fluid  seems  to  result  from  an  act  of 
simple  physical  transudation ;  for  it  has  been  found  that,  when  the  serum  of  the 
blood  is  made  to  percolate  through  thin  animal  membranes,  the  water  charged 
with  saline  matter  passes  through  them  much  more  readily  than  the  albumen,  a 
part  of  which  is  kept  back  (§  227). — The  great  use  of  Areolar  tissue  appears  to 
be,  to  connect  together  organs  and  parts  of  organs,  which  require  a  certain  degree 
of  motion  upon  one  another :  and  to  envelop,  fix,  and  protect  the  bloodvessels, 
nerves,  and  lymphatics  with  which  these  organs  are  to  be  supplied.  It  can 

1  The  discovery  that  the  Areolar  tissue  is  not  a  peculiar  elementary  form,  but  a  com- 
bination of  the  two  elements  previously  described,  was  first  made  by  Messrs.  Todd  and 
Bowman,  and  announced  in  their  excellent  "Physiological  Anatomy,"  vol.  i.  p.  83,  Am.  Ed. 


OF   THE   SIMPLE   FIBROUS   TISSUES. 


227 


scarcely  be  said  to  enjoy  any  vital  powers,  and  is  connected  solely  with  physical 
actions  (§  134).  It  is  extensible  in  all  directions,  and  very  elastic,  in  virtue  of 
the  physical  arrangement  of  its  elements ;  and  it  possesses  no  contractility,  except 
that  which  it  derives  from  the  smooth  muscular  fibre-cells  (Fig.  79)  which  are 
frequently  intermingled  with  its  other  elements,  sometimes  very  copiously.  It 
cannot  be  said  to  be  endowed  with  sensibility ;  for  the  nerves  which  it  contains 
seem  to  be  merely  en  route  to  other  organs,  and  not  to  be  distributed  to  its  own 
elements.  And  its  asserted  powers  of  absorption  and  secretion  appertain  rather 
to  the  walls  of  its  capillary  bloodvessels,  than  to  the  threads  and  bands  of  which 
it  is  itself  composed. 

Fig.  21. 


The  two  elements  of  Areolar  tissue,  in  their  natural  relations  to  one  another :  1,  the  white  fibrous  element, 
with  cell-nuclei,  9,  sparingly  visible  in  it ;  2,  the  yellow  fibrous  element,  showing  the  branching  or  anastomos- 
ing character  of  its  fibrillas ;  3,  fibrillae  of  the  yellow  element,  far  finer  than  the  rest,  but  having  a  similar 
curly  character ;  8,  nucleolated  cell-nuclei,  often  seen  apparently  loose.  From  the  areolar  tissue  under  the 
pectoral  muscle,  magnified  350  diameters. 

223.  It  has  been  already  mentioned  (§  118)  that  the  foregoing  tissues  maybe 
developed  in  two  different  modes ;  namely,  either  by  the  transformation  of  cells, 
or  by  the  fibrillation  of  a  blastema.  The  former  was  the  sole  mode  of  develop- 
ment assigned  by  Schwann,  and  the  latter  was  represented  by  Henle  in  the  same 
light;  but  other  observers  have  shown  that  each  of  these  eminent  histologists 
was  correct,  save  in  the  exclusiveness  of  his  view;  since  both  the  first  develop- 
ment and  the  subsequent  regeneration  of  these  tissues  have  been  seen  to  take 
place  after  either  of  these  methods.  It  is  in  their  reproduction  after  injury,  that 
the  process  may  be  most  conveniently  studied ;  and  the  following  account  of  it 
is  founded  on  the  statements  of  Mr.  Paget,1  who  has  specially  attended  to  this 
inquiry. — The  development  of  White  fibrous  tissue,  in  the  form  of  Areolar  tex- 
ture, from  cells,  may  be  observed  in  the  material  of  granulations,  or  in  that  of 

1  "Lectures  on  the  Processes  of  Repair  and  Reproduction  after  Injuries,"  in  "Medical 
Gazette,"  1849,  vol.  xliii.  pp.  1069-1071. 


228 


OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 


Fig.  22. 


Development  of  fibres  from 
cells :  a,  circular  or  oval  nucle- 
ated cells ;  b,  the  same  becom- 
ing pointed ;  c,  the  same  become 
fusiform,  the  nuclei  being  still 
apparent  ;d,  the  same  elongated 
into  fibres,  the  nuclei  having 
disappeared. 


inflammatory  adhesions  and  indurations.  The  cells  first  formed  in  the  plastic 
exudation  are  round,  very  slightly  granular,  from  1-1500  to  l-2000th  of  an  inch 
in  diameter ;  they  have  a  distinct  cell-wall,  which  is  readily  brought  into  view 
by  the  action  of  water,  if  not  apparent  at  first ;  and 
they  present  a  round  dark-edged  nucleus,  whose  sharp 
definition  distinguishes  it  from  that  of  the  colorless  cor- 
puscles of  the  blood,  to  which  these  cells  otherwise  bear 
a  close  resemblance.  It  is  in  this  nucleus  that  the  first 
developmental  change  shows  itself,  for  it  assumes  an 
oval  form,  and  its  substance  becomes  clearer  and  brighter. 
Very  soon,  however,  the  cell  itself  elongates  at  one  or 
both  ends,  so  as  to  assume  the  caudate,  fusiform,  or  lanceo- 
late shape  (Fig.  22) ;  and  its  contents  become  more  mi- 
nutely and  distinctly  granular,  whilst  the  cell-wall  thins 
away  or  becomes  blended  with  its  enclosure.  As  the 
cells  elongate  more  and  more,  so  as  to  assume  the  fila- 
mentous form,  they  also  arrange  themselves  in  such  a 
manner  that  the  thickest  portion  of  one  is  engaged  be- 
tween the  thinner  ends  of  the  two  or  more  adjacent  to 
it;  and  thus  fasciculi  are  gradually  formed,  of  which 
every  fibre  is  developed  from  one  elongated  cell,  except 
where  two  or  more  cells  have  united  end  to  end,  so  as 
to  form  one  long  continuous  filament.1  In  the  produc- 
tion of  areolar  tissue  in  inflammatory  exudations  or  in 
granulating  wounds,  the  nuclei  of  these  fibre-cells  ap- 
pear to  waste  and  be  absorbed ;  but  in  the  normal  course 
of  development,  which  may  be  seen  to  take  place  on 
this  plan  in  the  subcutaneous  areolar  tissue  of  the  foetus,  as  well  as  in  many 
other  situations,  it  is  probable  that  they  develop  themselves  into  the  "  nuclear 
fibres"  of  Henle",  which  constitute,  in  fact,  the  Yellow  or  elastic  filaments  that 
are  intermingled  with  the  white  in  this  tissue. 

224.  The  development  of  the  White  fibrous  tissue  by  the  fibrillation  of  a 
nucleated  blastema,  without  any  intervening  cell-formation,  may  be  observed 
in  the  organization  of  the  material  by  which  the  filling  up  of  subcutaneous 
wounds  is  usually  accomplished ;  and  seems  to  be  the  mode  in  which  the  first 
production  of  tendons  and  ligaments  is  normally  accomplished.  The  blastema, 
when  first  effused,  seems  like  a  mere  fibrinous  exudation,  usually  containing 
a  quantity  of  finely-molecular  or  dimly-shaded  substance,  but  having  no  appear- 
ance of  distinct  nuclei ;  these,  however,  gradually  present  themselves  in  it,  as 
if  they  were  formed  by  the  aggregation  of  molecules;  and  they  presently  appear 
as  oval  bodies  with  dark  hard  outlines,  which  soon  become  elongated,  and  are 
so  firmly  imbedded  in  the  surrounding  substance  that  they  can  scarcely  be  dis- 
lodged. The  blastema  gradually  acquires  a  more  and  more  distinct  fibrous 
appearance,  and  at  last  exhibits  a  regular  filamentous  structure ;  the  nuclei 
themselves  undergoing  little  change  during  this  time,  but  appearing  to  govern 
the  direction  of  the  fibrillation.  As  the  texture  goes  on  to  completion,  the 
nuclei  are  either  absorbed,  which  seems  to  be  the  case  in  the  connecting  tissue 
formed  for  the  reparation  of  injuries,  as  well  as  in  the  normal  development  of 
tendons;  or  they  undergo  a  further  development  into  <( nuclear  fibres."2  This  is 
effected  by  their  extension  at  both  ends,  so  that  the  nuclei  thus  prolonged  meet 
and  unite ;  their  particles  taking  on  that  very  uniform  linear  arrangement,  by 

1  It  was  asserted  by  Schwann  that  each  of  these  elongated  cells  splits  up  into  several 
filaments ;  but  Mr.  Paget  agrees  with  many  other  observers  in  considering  this  representa- 
tion erroneous. 

2  See  Henl^'s  "  Allgemeine  Anatomic,"  traduit  par  Jourdain,  torn.  i.  pp.  202,  406. 


OF   THE    SIMPLE   FIBROUS   TISSUES.  229 

which  the  fibres  of  this  tissue  seem  to  be  characterized ;  and  sometimes  perhaps 
undergoing  a  partial  or  complete  development  into  cells  (§  221). — The  rate  at 
which  the  production  of  fibrous  tissue  takes  place  in  the  manner  now  described, 
is  at  first  very  rapid ;  well-marked  filaments  being  detectable  in  the  blastema 
within  seven  or  eight  days;  and  the  tenacity  of  the  bond  thus  formed  between 
the  two  ends  of  a  divided  tendon  is  such,  that,  in  one^of  Mr.  Paget's  experi- 
ments, within  ten  days  after  the  operation,  the  reunited  tendo-Achillis  of  a 
rabbit  (the  new  tissue  being  a  cord  of  not  more  than  two  lines  in  its  chief  dia- 
meter) supported  a  weight  of  above  fifty  pounds.  The  subsequent  changes  take ' 
place  more  slowly;  but  the  repartition  of  divided  tendons  has  been  found  to 
be  so  complete  within  five  months  after  the  operation,  that  no  trace  of  the  sec- 
tions could  be  discovered  even  by  microscopic  examination. — It  is  important^ 
observe  that  the  blastema  which  undergoes  this  self-organization,  is  not  an  in- 
flammatory exudation,  but  one  which  is  much  better  adapted  for  the  reparative 
process.  For,  as  Mr.  Paget  has  observed,  in  experimenting  upon  the  sub- 
cutaneous division  of  tendons,  the  effusion  which  is  first  poured  forth  after  the 
shock  of  the  injury  contains  exudation-cells,  which  begin  to  undergo  the  changes 
described  in  the  preceding  paragraph,  but  are  not  developed  beyond  the  state 
in  which  they  appear  spindle-shaped.  And  it  is  not  until  about  forty-eight 
hours  have  elapsed  (in  the  rabbit),  that  the  true  reparative  material  begins  to 
appear.  This  material  must  be  looked  upon  as  having  undergone  a  much  higher 
elaboration  than  the  inflammatory  exudation  has  received  ;  since  it  can  at  once 
pass  on  to  that  ultimate  condition,  which  is  only  attained  in  the  other  case  by 
an  intermediate  process  of  cell-life.  But  we  can  scarcely  fail  to  recognize,  also, 
the  influence  of  the  healthful  condition  of  the  surrounding  tissues,  in  promoting 
development  by  the  vital  force  which  they  impart  (§  27);  the  state  of  inflamma- 
tion being  essentially  one  of  diminished  vitality  of  the  solid  tissues,  and  its 
existence  therefore  rendering  them  less  liable  to  promote  the  organization  of 
the  plastic  material  thrown  out  in  their  proximity.  Accordingly  we  shall  find 
hereafter  (CHAP.  xi.  SECT.  3),  that  in  proportion  to  the  degree  of  the  inflam- 
matory change  in  the  solids,  does  it  tend  to  depress  the  vitality  of  the  effused 
blastema,  so  as  to  retard  or  even  to  prevent  its  due  development,  and  to  occa- 
sion the  degradation  of  the  whole  or  of  the  greater  part  of  it  to  the  condition  of 
pus. 

225.  At  what  precise  time,  or  by  what  means,  the  chemical  change  occurs, 
by  which  the  fibrinous  constituents  of  the  plastic  exudation  are  converted  into 
the  gelatinous  basis  of  the  white  fibrous  tissue,  we  have  no  certain  knowledge ; 
there  are  indications  that  the  process  is  a  gradual  one,  and  involves  the  exist- 
ence of  various  intermediate  gradations  (§  30) ;  and  a  more  attentive  chemical 
examination  of  fibrous  tissues  in  progress  of  formation,  would  probably  throw 
considerable  light  upon  the  nature  of  the  transition. — All  that  is  known  of  this 
subject,  however,  indicates  that  the  production  of  the  gelatigenous  tissues  takes 
place  solely  at  the  expense  of  the  fibrinous  component  of  the  blood ;  and  that 
gelatin  employed  as  food  cannot  become  converted  into  fibrous  tissue,  except 
by  passing  through  this  intermediate  condition,  into  which  it  is  next  to  certain 
that  it  can  never  be  transmuted.  For  although  there  is  ample  evidence  of  the 
conversion  of  the  albuminous  compounds  into  the  gelatinous,  in  the  living  body, 
yet  the  reconversion  of  the  gelatinous  into  the  albuminous  appears  to  be  a  com- 
plete impossibility.  (See  CHAP,  vii.) 

2.    Of  the  Fibro- Cellular  Membranes,  and  their  Appendages. 

226.  The  body  of  Man,  in  common  with  that  of  all  the  higher  animals,  con- 
tains numerous  and  extensive  membranous  expansions,  which  form  its  external 
investment  and  line  its  internal  cavities,  and  which  are  consequently  free  or 


230  OF   THE   PRIMARY  TISSUES   OF   THE    HUMAN   BODY. 

unattached  on  one  of  their  surfaces,  whilst  the  other  is  continuous  with  the 
tissues  which  they  overlie.  The  principal  part  of  the  substance  of  all  these 
membranes  is  made  up  of  the  Simple  Fibrous  tissues  described  in  the  preceding 
section,  interwoven  so  closely  as  to  form  a  sort  of  condensed  areolar  tissue,  with 
which  bloodvessels,  lymphatics,  nerves,  and  smooth  muscular  fibres  may  be 
blended  in  varying  proportions.  The  fibres  of  this  tissue  are  continuous  with 
those  of  the  looser  texture  that  lies  beneath  its  attached  surface,  and  there  is  con- 
sequently no  definite  boundary  to  the  membrane  on  that  side.  But  the  free  sur- 
.face  is  covered  by  a  layer  of  basement  membrane,  which  forms  a  complete  limit, 
not  only  to  the  fibres,  but  also  to  the  vessels,  i^rves,  &c.,  of  the  subjacent  tissue. 
This  membrane,  it  is  true,  cannot  always  be  distinguished;  but  there  is  strong 
analogical  ground  for  believing  in  the  universality  of  its  presence.  Supported 
by  this  basement  membrane,  and  covering  what  would  otherwise  be  its  exposed 
face,  we  find  one  or  more  layers  of  cells ;  and  these  may  have  very  different 
endowments  in  different  situations,  so  as  to  impart  very  diversified  characters 
to  the  surfaces  which  they  form. — Whilst  all  the  membranes  now  under  con- 
sideration agree  in  consisting  of  the  foregoing  elements,  they  differ  amongst 
each  other  in  regard  alike  to  the  relative  proportions  of  their  components,  and 
to  the  mode  in  which  they  are  arranged.  There  are  three  principal  categories, 
however,  under  which  they  are  capable  of  being  grouped  together,  viz,  the  Skin, 
the  Mucous  Membranes,  and  the  Serous  Membranes  ; — the  first  of  these  forming 
the  external  integument ;  the  second  being  continued  from  it  at  various  points, 
so  as  to  line  all  the  open  cavities  of  the  body ;  and  the  third  forming  closed 
sacs,  which  intervene  between  surfaces  that  rub  or  glide  one  over  the  other. 
Of  these,  the  Serous  Membranes  are  the  least  distinguished  by  the  speciality  of 
their  endowments ;  and  they  may,  therefore,  be  advantageously  considered  in 
the  first  instance. 

227.  Serous  and  Synovial  Membranes. — These  membranes,  which  are  so 
named  from  the  nature  of  the  fluid  with  which  their  free  surface  is  moistened, 
are  thin  and  transparent,  so  as  to  allow  the  colour  of  subjacent  parts  to  be  seen 
through  them.  They  are  endowed,  however,  with  a  considerable  amount  of 
strength,  and  possess  much  elasticity  in  situations  where  mobility  is  particularly 
required.  Their  free  surface,  which  is  smooth  and  glistening,  is  found,  when 
examined  with  a  microscope,  to  be  covered  with  a  single  layer  of  flattened  poly- 
gonal cells,  usually  of  a  tolerably  regular  hexagonal  shape,  constituting  what  is 
designated  as  a  "tessellated"  or  a  "pavement  epithelium"  (§  230);  and  beneath 
this  a  layer  of  basement  membrane  is  affirmed  by  Messrs.  Todd  and  Bowman  to  be 
clearly  distinguishable. — The  principal  part  of  the  substance  of  the  membrane  is 
composed  of  what  may  be  considered  as  condensed  areolar  tissue,  into  which  the 
yellow  fibrous  element  largely  enters,  its  filaments  interlacing  into  a  beautiful 
network,  and  thus  imparting  a  high  degree  of  elasticity  to  its  texture.  This 
gradually  passes  into  that  laxer  variety,  by  which  the  membrane  is  attached  to 
the  parts  it  covers,  and  which  is  commonly  known  as  the  "  sub-serous"  tissue ; 
here  fat-cells  are  not  unfrequently  found.  The  bloodvessels  of  Serous  mem- 
branes usually  have  a  simple  plexiform  arrangement,  parallel  to  the  surface,  and 
are  seldom  very  copious ;  but  those  of  Synovial  membranes  are  far  more  nume- 
rous, and  their  minutest  ramifications  are  remarkable  for  their  length  and  tortu- 
osity (Fig.  53) — a  disposition  which  seems  to  have  reference  to  the  nutrition  of 
the  Cartilage  beneath.  The  Synovial  membranes  are  further  distinguished  by 
the  presence  of  numerous  fringe-like  processes,  of  extreme  vascularity,  hanging 
down  loosely  into  the  cavity  of  the  joint;  these  are  covered  with  an  epithelium 
of  a  very  different  character  from  that  already  described,  its  cells  being  large, 
spheroidal,  and  very  loosely  attached  to  the  surface  beneath ;  and  there  can  be 
little  doubt  that  they  constitute  the  secreting  apparatus  for  the  synovial  fluid. 
The  JBursse  interposed  between  the  prominences  of  bones  and  the  tendons  or  in- 


SEROUS   AND   SYNOVIAL  MEMBRANES.  231 

teguments  that  glide  over  them,  or  amongst  the  tendons  themselves,  appear  to 
be  essentially  similar  to  the  synovial  membranes  in  the  arrangement  of  their 
elements ;  but  their  epithelium  is  less  regular,  and  shows  numerous  gradations 
of  cell-growth. — The  fluid  of  the  Serous  sacs  is  normally  only  sufficient  to  keep 
their  surfaces  moist,  and  its  composition  in  the  healthy  state  is  consequently  in- 
determinable. In  various  abnormal  conditions,  however,  it  accumulates  in  large 
amount ;  and  as  this  may  occur  from  simple  obstruction  to  the  venous  circulation, 
without  any  morbid  affection  of  the  membrane  itself,  it  is  probable  that  the  fluid 
which  thus  transudes  is  very  similar  in  quality  to  the  natural  serous  exhalation. 
As  a  general  rule,  the  fluid  effused  from  Serous  membranes  resembles  the  serum 
of  the  blood  with  a  considerable  proportion  of  its  albumen  kept  back,  the  salts 
being  present  in  nearly  their  normal  amount ;  the  amount  of  albumen  present, 
however,  is  subject  to  great  variation,  but  the  recent  researches  of  Schmidt  and 
Lehmann1  have  shown  that  it  presents  a  remarkable  degree  of  constancy  in  the 
exudations  from  each  membrane.  Thus,  the  transudation  of  the  pleura  contains 
about  2.85  per  cent,  of  albumen;  that  of  the  peritoneum  only  1.18  per  cent.,  that 
of  the  arachnoid  no  more  than  0.6  or  0.8  percent.,  and  that  of  the  subcutaneous 
areolar  tissue  as  little  as  0.36  per  cent.  There  is  strong  reason  to  believe  that 
the  retention  of  the  chief  part  of  the  albumen,  when  the  water  and  the  salines 
transude  the  coats  of  the  vessels,  is  merely  the  result  of  the  physical  arrangement 
of  the  elements  of  the  membranes  ;  it  having  been  shown  by  Valentin,3  that  the 
filtration  of  albuminous  fluid  through  dead  serous  membranes  is  attended 
with  the  same  result.  And  it  can  scarcely  be  doubted,  therefore,  that  the  varia- 
tion in  the  quantity  allowed  to  pass  by  different  membranes,  is  to  be  attributed 
to  their  physical  peculiarities.  In  proportion  to  the  increase  of  the  pressure  to 
which  the  blood  may  be  subjected  (as  through  an  obstruction  to  its  return,  or  any 
other  cause),  is  the  increase  in  the  proportion  of  albumen  which  transudes;  and 
in  some  cases  of  extreme  obstruction,  without  inflammation,  the  presence  of  soft 
jelly-like  masses  or  of  strings  of  fibrin,  indicates  that  even  this  component  of  the 
blood  may  be  made  to  transude  by  a  further  augmentation  of  pressure.3  The 
fluid  of  the  Synovial  capsules  and  of  the  Bursa3  is  of  a  much  more  viscid  charac- 
ter, almost  resembling  oil  in  its  glairy  appearance,  and  not  mixing  readily  with 
other  liquids ;  its  composition  has  not  been  precisely  made  out ;  but  it  certainly 
contains  a  far  larger  proportion  of  albuminous  matter  than  the  serous  exudations, 
and  it  may  be  probably  considered  as  a  true  product  of  secretion.  The  pur- 
pose of  all  these  fluids  is  obviously  to  diminish  friction  between  surfaces  which 
are  exposed  to  mutual  attrition ;  and  the  quantity  of  albumen  they  respectively 
contain  seems  to  have  reference  to  the  amount  of  motion  and  of  pressure  to  which 
the  membranes  are  subjected,  being  least  in  the  cavities  of  the  brain,  somewhat 
more  in  that  of  the  peritoneum,  two  and  a  half  times  as  much  in  that  of  the 
pleura,  and  many  times  greater  in  the  synovial  capsules. — It  is  probable  that  the 
rate  of  nutrition  of  the  Serous  membranes  is  not  rapid  under  ordinary  circum- 
stances ;  since  there  appears  to  be  but  little  vital  activity  in  them.  Their  epi- 
thelium exhibits  no  indications  of  being  frequently  cast  off  and  renewed,  like 
that  of  many  other  parts  ;  and  is  probably  very  permanent  in  its  character.  The 
membranes  of  the  Synovial  capsules  and  of  the  Bursae,  however,  obviously  possess 
a  much  higher  vital  activity,  being  themselves  more  vascular,  and  having  an 
epithelium  which  is  evidently  in  continual  course  of  renewal ;  and  this  activity 
seems  connected  with  their  secretory  office.  All  these  membranes  are  very 
readily  regenerated  after  loss  of  substance ;  and  they  are  even  produced  de  novo, 

1  "  Lehrbuch  der  Physiologischen  Chemie,"  band  ii.  pp.  248-50. 

2  "  Lehrbuch  der  Physiologie,"  band  i.  p.  601. 

3  This  has  been  experimentally  demonstrated  by  Mr.  Robinson,  who  has  shown  that  the 
urine  may  be  rendered  albuminous  or  even  fibrinous  by  the  application  of  a  ligature  round 
the  renal  vein.     ("  Medical  Gazette,"  June  28,  1844.) 


232  OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 

when  circumstances  call  for  their  existence.  Thus  we  find  regular  synovial 
capsules  formed  around  "  false  joints/ '  and  newbursae  developed  between  portions 
of  the  cutaneous  surface  exposed  to  much  friction,  and  the  subjacent  bones.  In 
all  these  cases,  the  cysts  appear  to  originate  in  an  enlargement  and  fusion  of 
the  normal  interspaces  of  areolar  tissue,  and  in  a  condensation  of  the  tissue  itself 
around  the  cavities  thus  formed.  Serous  membranes,  when  inflamed,  are  pecu- 
liarly prone  to  throw  out  plastic  exudations,  which  become  organized  into  "  false 
membranes;"  and  these  frequently  constitute  "  adhesions"  connecting  their  oppo- 
site surfaces.  In  this  respect,  however,  the  synovial  membranes  show  a  marked 
difference  from  the  more  general  type ;  "  adhesive  inflammation"  being  compara- 
tively rare  in  them.1 

228.  Mucous  Membranes,  and  their  Glandular  Appendages. — The  Mucous 
membranes,  like  the  serous,  derive  their  name  from  the  attributes  of  the  fluid 
with  which  they  are  moistened;  this  fluid,  however,  is  not  a  mere  exudation  of 
the  watery  part  of  the  blood,  but  is  a  regular  secretion,  peculiarly  consistent  and 
tenacious  in  its  character,  whose  purpose  is  obviously  protective.  These  mem- 
branes are  usually  thicker  than  the  serous,  and  are  more  or  less  opaque;  they 
possess,  however,  comparatively  little  tenacity;  and  the  reddish  color  which 
they  exhibit,  both  during,  life  and  after  death,  is  dependent  on  the  blood  con- 
tained in  their  copious  bloodvessels,  and  may  vary  greatly  in  intensity,  according 
to  the  degree  in  which  these  vessels  are  congested.  There  is  relatively  less 
fibrous  tissue  in  these  membranes  than  in  the  serous,  a  very  large  part  of  their 
substance  being  formed  by  bloodvessels  and  lymphatics;  and  there  are  some 
situations  in  which  it  is  almost  entirely  wanting,  as  in  the  superficial  stratum  of 
the  gastro-intestinal  mucous  membrane,  where,  immediately  beneath  the  base- 
ment membrane,  we  find  the  vessels  spread  out  amidst  a  soft  granular  matter, 
with  a  few  corpuscles  resembling  free  nuclei  and  granule-cells.2  The  fibres  of 
the  deeper  layer  are  continuous  with  those  of  the  "  submucous"  areolar  tissue. 
The  presence  of  a  distinct  basement  membrane  cannot  be  always  demonstrated, 
especially  where  the  membrane  presents  a  simple  even  surface ;  but  where  the 
membrane  is  depressed  into  follicles  (Fig.  23,  F,  F),  or  prolonged  into  villi  (v,  v), 
the  existence  of  the  basement  membrane  may  usually  be  clearly  made  out, 
though  it  can  seldom  be  separated  from  the  subjacent  tissue.  The  bloodvessels 
and  lymphatics  with  which  the  Mucous  membranes  are  copiously  supplied,  form 
a  very  minute  and  closely-set  plexus  which  spreads  out  beneath  the  basement 
membrane ;  advancing  with  it  into  the  villi  which  it  covers  (Fig.  27),  and  sur- 
rounding the  follicles  which  it  lines  (Fig.  28).  The  "  follicular"  arrangement 
is  very  common  in  mucous  membranes;  the  follicles  being  sometimes  isolated 
from  each  other,  and  sometimes  clustered  so  thickly  that  there  is  only  room  for 
bloodvessels  and  connective  tissue  between  them.  The  "villous"  character,  on 
the  other  hand,  is  for  the  most  part  limited  to  a  portion  of  the  gastro-intestinal 
mucous  membrane.  The  entire  surface  of  the  Mucous  membranes  is  covered 
by  an  Epithelial  layer  (e),  which  not  only  lies  upon  their  simple  flat  expansions, 
but  also  invests  the  villi  and  lines  the  follicles;  the  structural  characters  and 
physiological  uses  of  this  epithelium,  however,  are  so  different  in  different  situa- 
tions, and  even  in  closely-adjacent  parts  of  the  same  stratum,  as  to  require  a 
more  special  description  (§  230).  These  cells,  instead  of  forming  a  comparatively 
permanent  stratum,  like  the  epithelium  of  serous  membranes,  are  in  a  state  of 
continual  change  and  renewal;  the  older  layers  falling  off,  whilst  new  ones  are 
produced  from  the  surface  or  from  the  substance  of  the  basement  membrane. 
It  is  chiefly  on  the  bronchio-pulmonary  and  gastro-intestinal  mucous  membranes, 

1  The  anatomy  and  physiology  of  the  serous  and  Synovial  Membranes  has  been  ably 
treated  of  by  Dr.  Brinton,  in  his  Article  on  that  subject  in  the  "  Cyclopedia  of  Anatomy  and 
Physiology,"  vol.  iv.  p.  510. 

2  See  Dr.  Sharpey,  in  "Quain's  Elements  of  Anatomy,"  vol.  ii.  p.  81,  Am.  Ed. 


MUCOUS    MEMBRANES. 


233 


that  we  meet  with  the  peculiar  secretion  termed  Mucus  ;  which  appears  to  be  ex- 
pressly formed  to  shield  these  surfaces  from  the  irritation  they  would  suffer, 


Fig.  23. 


Diagram  of  the  structure  of  an  involuted  Mucous  Membrane,  showing  the  continuation  of  its  elements  in 
the  follicles  and  villi:  F,  F,  two  follicles;  6,  basement  membrane;  c,  submucous  tissue;  e,  epithelium;  v,  vascu- 
lar layer;  n,  nerve;  v,  villus,  covered  with  epithelium;  v',  villus  whose  epithelium  has  been  shed. 

through  the  contact  of  air,  or  of  solids  or  liquids.  This  secretion  is  also  found 
on  the  lining  membrane  of  the  larger  excretory  ducts  of  most  of  the  glands ; 
and  it  is  mixed  in  greater  or  less  amount,  with  most  of  the  secretions  discharged 
by  them.  It  is  found  also  upon  the  lining  membrane  of  the  gall-bladder,  and 
of  the  urinary  bladder.  When  these  membranes  are  in  a  state  of  unusual  irri- 
tation, the  amount  of  mucus  which  they  discharge  is  very  considerable;  but  it 
ordinarily  forms  an  extremely  thin  layer.  The  characters  of  Mucus,  obtained 
from  various  sources,  are  by  no  means  invariable.  In  general,  however,  it  may 
be  described  as  a  fluid  of  peculiar  viscidity,  either  colorless  or  slightly  yellow, 
transparent  or  nearly  so,  incapable  of  mixing  with  water,  and  sinking  in  it, 
except  when  buoyed  up  by  bubbles  entangled  in  its  mass,  which  is  commonly 
the  case  with  the  bronchial  and  nasal  mucus.  This  fluid  contains  from  4?  to 
6?  per  cent,  of  solid  matter,  of  which  a  small  part  consists  of  salts  resembling 
those  of  the  blood ;  whilst  the  chief  organic  constituent  is  a  substance  termed 
Mucin,  to  which  the  characteristic  properties  of  the  secretion  are  due.  This 
appears  to  be  an  albuminous  compound,  altered  by  the  action  of  an  alkali;  for, 
as  Dr.  Babington  has  shown,  any  albuminous  fluid  may  be  made  to  present  the 
peculiar  viscidity  of  mucus,  by  treating  it  with  liquor  potassaa.  That  the  mucin 
of  mucus  is  held  in  solution  by  an  alkali,  appears  from  this,  that  it  is  readily 
precipitated  by  acids,  which  neutralize  the  base  :  and  that  a  sort  of  faint  coagu- 
lation may  be  induced  even  by  water,  which  withdraws  the  base  from  it.  When 
Mucus  is  examined  with  the  Microscope,  it  is  found  to  contain  numerous  epi- 
thelium-scales (or  flattened  cells);  together  with  round  granular  corpuscles,  con- 
siderably larger  than  those  of  the  blood,  and  closely  resembling  the  nuclei  of  the 
epithelium-cells,  which  are  commonly  termed  mucus-corpuscles.  In  the  more 


234  OF   THE   PRIMARY   TISSUES   OF  THE    HUMAN   BODY. 

opaque  mucus,  discharged  from  membranes  in  a  state  of  irritation  or  inflamma- 
tion, these  corpuscles  are  present  in  greatly  increased  amount ;  and  cells  are 
often  developed  around  them. 

229.  The  essential  character  of  the  Mucous  Membranes,  in  regard  alike  to 
their  offices  and  their  arrangement,  is  altogether  different  from  that  of  the  Serous 
and  Synovial  membranes.  For  whilst  the  latter  form  shut  sacs,  whose  contents  are 
destined  to  undergo  little  change,  the  former  line  tubes  and  cavities  which  have 
free  outward  communications;  and  they  thus  constitute  the  medium  through 
which  nearly  all  the  material  changes  are  effected  that  take  place  between  the 
living  organism  and  the  external  world.  Thus,  in  the  gastro-intestinal  mucous 
membrane,  we  find  a  provision  for  reducing  the  food,  by  means  of  a  solvent  fluid 
poured  out  from  its  follicles;  whilst  the  villi,  or  root-like  filaments,  which  are 
closely  set  upon  its  surface  towards  its  upper  part,  are  especially  adapted  to  absorb 
the  nutrient  materials  thus  reduced  to  the  liquid  state.  This  same  membrane, 
at  its  lower  part,  constitutes  an  outlet  through  which  are  cast  out,  not  merely 
the  indigestible  residuum  of  the  food,  but  also  the  excretions  from  numerous 
minute  glandulae  in  the  intestinal  wall,  which  result  from  the  decomposition  of 
the  tissues,  and  which  must  be  separated  and  cast  forth  from  them  to  prevent 
further  decay.  Again,  the  bronchio-pulmonary  mucous  membrane  serves  for  the 
introduction  of  oxygen  from  the  air,  and  for  the  exhalation  of  water  and  car- 
bonic acid.  And  lastly,  the  mucous  membranes  are  continuous  with  the  cell- 
lined  vesicles  or  tubes  of  the  various  Grlands,  which  are  the  instruments  whereby 
their  respective  products  are  eliminated  from  the  blood.  The  changes  to  which 
the  Mucous  Membranes  are  thus  subservient,  however,  do  not  seem  to  involve 
the  vital  activity  of  any  other  of  their  components  than  the  Epithelial  cells, 
and  of  the  basement  membrane  as  probably  ministering  to  their  production. 
Here,  as  elsewhere,  the  fibrous  elements  appear  to  have  but  a  passive  relation 
to  the  vital  operations  of  the  tissue  into  which  they  enter;  and  there  is  no  rea- 
son to  think  that  the  copious  supply  of  blood  which  the  mucous  membranes 
receive  has  any  relation  to  their  nutrition.  In  fact,  we  might  fairly  describe 
the  Mucous  membranes  generally  as  essentially  consisting  of  a  plexus  of  blood- 
vessels in  immediate  relation  with  a  stratum  of  epithelial  cells;  the  fibres  having 
merely  a  connective  office,  and  their  absence  not  being  in  any  way  detrimental, 
if  they  be  not  required  for  this  purpose.  Thus,  the  tubuli  and  follicles  of  many 
glands  are  composed  of  a  basement  membrane  and  epithelial  layer,  prolonged 
from  those  of  the  mucous  membranes  with  which  they  are  in  connection,  and 
yet  may  have  no  fibrous  tissue  properly  appertaining  to  them,  being  imbedded 
in  the  substance  of  the  glands,  and  closely  surrounded  by  bloodvessels.  Mucous 
membranes  are  not,  for  the  most  part,  copiously  supplied  with  nerves,  nor  do 
they  possess  much  sensibility;  there  are  exceptions,  however,  chiefly  in  the  case 
of  those  which,  being  near  the  inlets  and  outlets  of  the  body,  are  endowed  with 
sensibility,  apparently  for  the  purpose  of  guarding  against  the  contact  or  admis- 
sion of  injurious  substances  (as  in  the  case  of  the  conjunctival,  buccal,  and 
laryngeal  membranes),  or  of  giving  notice  of  the  presence  of  excrementitious 
matters  requiring  ejection  by  muscular  power  (as  in  the  case  of  the  lining  mem- 
branes of  the  bladder  and  rectum).  Mucous  membranes,  when  diseased,  are  far 
less  disposed  than  the  serous  to  throw  out  plastic  exudations,  but  are  prone  to 
suppuration,  ulceration,  and  gangrene.  Their  regeneration  after  loss  of  sub- 
stance by  disease  or  injury,  takes  place  with  great  rapidity ;  but  although  a 
simple  membrane  may  be  'completely  restored,  yet  it  appears  from  observation 
of  the  healing  process  after  ulcers  of  the  large  intestine,  that  the  tubular  folli- 
cles are  not  reproduced.  A  complete  reproduction  of  the  follicular  structure 
takes  place,  however,  in  the  lining  membrane  of  the  uterus,  after  its  exuviation 
in  the  formation  of  the  Decidua  (CHAP.  xix.).  It  is  interesting  to  observe, 
that  where  a  portion  of  the  Cutaneous  surface  has  been  turned  inwards,  so  as  to 


MUCOUS   MEMBRANES. — EPITHELIUM. 


235 


form  part  of  the  boundary  of  one  of  the  internal  cavities  (as  in  the  plastic  ope- 
rations for  the  restoration  of  lips,  eyelids/ &c.),  it  undergoes  a  gradual  modifi- 
cation in  its  characters,  and  comes,  after  a  time,  to  present  the  appearance  of  an 
ordinary  Mucous  membrane. 

230.  For  our  knowledge  of  the  constant  existence  of  the  Epithelium  as  an 
integral  constituent  of  the  Mucous  and  Serous  membranes,  and  for  our  apprecia- 
tion of  its  important  offices  in  the  economy,  we  are  entirely  indebted  to  the 
assistance  afforded  by  the  Microscope.  It  had  long  been  known  that  the  epider- 
mic layer  might  be  traced  continuously  from  the  lips  to  the  mucous  membrane 
of  the  mouth,  and  thence  down  the  oesophagus  into  the  stomach ;  and  that,  in 
the  strong  muscular  stomach  or  gizzard  of  the  granivorous  birds,  it  becomes 
quite  a  firm  horny  lining.  But  it  has  been  only  since  the  application  of  the 
Microscope  to  this  investigation,  that  a  continuous  layer  of  cells  has  been  traced, 
not  merely  along  the  whole  surface  of  the  mucous  membrane  lining  the  alimen- 
tary canal,  but  likewise  along  the  free  surfaces  of  all  other  Mucous  Membranes, 
with  their  prolongations  into  follicles  and  glands ;  as  well  as  on  the  Serous  and 
Synovial  membranes,  and  the  lining  membrane  of  the  heart,  bloodvessels,  and 
absorbents.  The  forms  presented  by  the  Epithelial  cells  are  various.  The  two 
chief,  however,  are  the  tessellated,  forming  the  "  pavement-epithelium ;"  and  the 
cylindrical  forming  the  "cylinder-epithelium."  The  "pavement-epithelium" 
covers  the  serous  and  synovial  membranes,  the  lining  membrane  of  the  blood- 
vessels, and  the  ultimate  follicles  or  tubuli  of  most  glandular  structures  con- 
nected with  the  skin  or  mucous  membranes,  as  also  the  mucous  membranes  them- 
selves, where  the  cylinder-epithelium  does  not  exist.  The  cells  composing  it  are 
usually  flattened  (Fig.  24,  A),  and  sometimes  so  polygonal  as  to  come  into  contact 
with  each  other  at  their  edges,  like  the  pieces  of  a  tessellated  pavement  (Fig.  13) ; 

Fig.  24. 


Separated  Epithelium-cells,  a,  with  nuclei, 
b,  and  nucleoli,  c,  from  mucous  membrane  of 
the  mouth. 


Pavement-Epithelium  of  the  Mucous 
Membrane  of  the  smaller  bronchial 
tubes ;  a,  nuclei  with  double  nucleoli. 


Fig.  25. 


but  they  sometimes  retain  their  rounded  or  oval  form,  and  are  separated  from 
each  other  by  considerable  interstices  (Fig.  24,  B).  This  last  form  seems  to  be 
the  commonest,  where  the  cells  are  most  actively  renewed,  so  that  they  have 
not  time  (so  to  speak)  to  be  developed 
into  a  continuous  stratum.  The  num- 
ber of  layers  is  commonly  small ;  and 
usually  there  is  only  a  single  one.  The 
"cylinder-epithelium"  is  very  differ- 
ently constituted.  Its  component  cells 
are  cylinders,  which  are  arranged  side 
by  side  (Fig.  25);  one  extremity  of 


each  cylinder  resting  upon  the  base- 
ment membrane,  whilst  the  other  forms 
part  »f  the  free  surface.  The  perfect 


Cylinder-Epithelium,  from  the  intestinal  villi  of  a 
rabbit;  a,  a,  membrane  connecting  their  free  surfaces, 
rendered  more  distinct  by  the  action  of  water. 


236  OF   THE   PRIMARY   TISSUES   OF  THE   HUMAN   BODY. 

cylindrical  form  is  only  shown,  however,  when  the  surface  on  which  the  cylinders 
rest  is  flat  or  nearly  so.  When  it  is  convex,  the  lower  ends  or  bases  of  the  cells  are 
of  much  smaller  diameter  than  the  upper  or  free  extremities ;  and  thus  each  has  the 
form  of  a  truncated  cone,  rather  than  of  a  cylinder ;  as  is  well  seen  on  the  cells 
covering  the  villi  of  the  intestinal  canal  (Fig.  23).  On  the  other  hand,  where  the 
cylinder-epithelium  lies  upon  a  concave  surface,  the  free  extremities  of  the  cells  may 
be  smaller  than  those  which  are  attached.  Moreover,  when  it  is  very  compactly 
arranged,  its  sides  may  be  flattened  against  each  other,  so  as  to  become  polygonal ; 
and  this  constitutes  the  prismatic  variety.  Sometimes  each  cylinder  is  formed  from 
more  than  one  cell,  as  is  shown  by  its  containing  two  or  more  nuclei ;  although 
its  cavity  seems  to  be  continuous  from  end  to  end.  And  occasionally  the  cylin- 
ders arise  by  stalk-like  prolongations,  from  a  pavement-epithelium  beneath.  The 
two  forms  of  Epithelium  pass  into  one  another  at  various  points ;  and  various 
transition-forms  are  then  seen ;  the  tessellated  scales  appearing  to  rise  more  and 
more  from  the  surface,  until  they  project  as  long-stalked  cells,  truncated  cones, 
or  cylinders.  The  cylinder-epithelium  covers  the  mucous  membrane  of  the  ali- 
mentary canal,  from  the  cardiac  orifice  downwards ;  it  is  found  also  in  the  larger 
ducts  of  most  glands  which  open  into  that  canal,  or  upon  the  external  surface, 
such  as  the  ductus  choledochus,  the  salivary  ducts,  those  of  the  prostate  and  Cow- 
per's  glands,  the  vas  deferens,  and  the  urethra.  In  all  these  situations,  it  comes 
into  connection  with  the  pavement-epithelium,  which  usually  lines  the  more  deli- 
cate canals  of  the  glands,  as  well  as  their  terminal  follicles.  There  are  certain 
parts,  moreover,  on  which  the  Epithelial  cells  retain  their  primitive  roundness, 
with  very  little  modification ;  such  cells  are  said  to  constitute  a  "  spheroidal  epi- 
thelium." The  most  important  example  of  it  is  presented  by  the  urinary  pas- 
sages, which  it  lines  from  the  pelvis  of  the  kidneys  to  the  inner  orifice  of  the 
urethra ;  but  it  is  also  found  in  the  excretory  ducts  of  the  mammary,  perspiratory, 
and  some  other  glands ;  and  presents  itself  also  as  the  characteristic  form  in 
many  situations,  in  which  the  secreting  process  is  most  actively  going  on.  This 
form  may  pass  by  insensible  gradations  into  either  of  the  other  two. 

231.  Both  the  two  principal  forms  of  Epithelial  cells  are  frequently  observed 
to  be  fringed  at  their  free  margins  with  delicate  filaments,  which  are  termed 
Cilia;  and  these,  although  of  extreme  minuteness,  are  organs  of  great  import- 
ance in  the  animal  economy,  through  the  extraordinary  motor  power  with  which 

they  are  endowed.     The  form  of  the  ciliary 

Fig.  26.  filaments  is   usually  a   little   flattened,  and 

tapering  gradually  from  the  base  to  the  point. 
Their  size  is  extremely  variable ;  the  largest 
that  have  been  observed  being  about  l-500th 
of  an  inch  in  length,  and  the  smallest  about 
1-13, 000th.  When  in  motion,  each  filament 
appears  to  bend  from  its  root  to  its  point,  re- 
vibratiie  or  ciliated  Epithelium;  a,  nucie-  turning  again  to  its  original  state,  like  the 

ated  cells,  resting  on  their  smaller  extremi-      stalks  of  COrn  when    depressed    by  the  Wind  ] 

ties;  &,  cilia.  an(j  wnen  a  number  are  affected  in  succession 

with  this  motion,  the  appearance  of  progres- 
sive waves  following  one  another  is  produced,  as  when  a  cornfield  is  agitated 
by  frequent  gusts.  When  the  ciliary  movement  is  taking  place  in  full  activity, 
however,  nothing  whatever  can  be  distinguished,  but  the  whirl  of  particles  in 
the  surrounding  fluid ;  and  it  is  only  when  the  rate  of  movement  slackens,  that 
the  shape  and  size  of  the  cilia,  and  the  manner  in  which  their  stroke  is 
made,  can  be  clearly  seen.  The  motion  of  the  cilia  is  not  only  quite  in- 
dependent (in  all  the  higher  animals  at  least)  of  the  will  of  the  animal,  but  is 
also  independent  even  of  the  life  of  the  rest  of  the  body ;  being  seen  after  the 
death  of  the  animal,  and  proceeding  with  perfect  regularity  in  parts  separated 


CILIARY   MOVEMENT.  237 

from  the  body.  Thus  isolated  epithelium-cells  have  been  seen  to  swim  about 
actively  in  water,  by  the  agency  of  their  cilia,  for  some  hours  after  they  have 
been  detached  from  the  mucous  surface  of  the  nose ;  the  ciliary  movement  has 
been  seen  fifteen  days  after  death  in  the  body  of  a  Tortoise,  in  which  putrefaction 
was  far  advanced;  and  even  in  Man,  according  to  the  recent  observations  of  M. 
Gosselin,1  it  may  be  observed  on  the  mucous  lining  of  the  trachea  for  as  long  as 
seven  days  after  death. — The  purpose  of  this  Ciliary  movement  is  obviously  to 
propel  fluids  over  the  surface  on  which  it  takes  place ;  and  it  is  consequently 
limited,  in  all  save  aquatic  animals,  to  certain  internal  surfaces  of  the  body,  and 
takes  place  in  the  direction  of  the  outlets,  towards  which  it  aids  in  propelling  the 
various  products  of  secretion.  A  layer  of  ciliated  epithelium,  of  the  tessellated 
form,  has  been  affirmed  by  Purkinje  and  Valentin  to  exist  upon  the  delicate  pia 
mater  which  lines  the  cerebral  cavities,  not  even  excepting  the  infundibulum  and 
the  aqueduct  of  Sylvius ;  but  from  the  recent  observations  of  Dittrich  and  Gerlach 
upon  decapitated  criminals,  it  is  doubtful  if  this  movement  takes  place  in  the 
Human  adult,  the  previously-cited  results  having  been  afforded  by  embryos  and 
by  the  lower  animals.2  A  cylindrical  epithelium  furnished  with  cilia  is  found 
lining  the  nasal  cavities,  except  over  the  olfactory  region,  the  frontal  sinuses, 
the  maxillary  antra,  the  lachrymal  ducts  and  sac,  the  posterior  surface  of  the 
velum  pendulum  palati,  and  fauces,  the  Eustachian  tube,  the  larynx,  trachea,  and 
bronchi  to  their  finest  divisions,  where  it  passes  into  the  tessellated  form,  the 
upper  portion  of  the  vagina,  the  uterus,  and  the  Fallopian  tubes.  The  function 
of  the  cilia  in  all  these  cases  appears  to  be  the  same ;  that  of  propelling  the  se- 
cretions, which  would  otherwise  accumulate  on  these  membranes,  towards  the 
exterior  orifices,  whence  they  may  be  carried  off. 

232.  Of  the  agency  to  which  the  Ciliary  movement  is  immediately  due,  it  is 
difficult  to  give  any  precise  account.     Although  the  fact  cannot  be  substantiated 
in  the  case  of  the  minute  cilia  of  the  epithelium-cells  of  Man,  yet  a  careful 
examination  of  the  much  larger  cilia  of  some  of  the  lower  animals,  especially 
aquatic  Mollusks  and  Animalcules,  suggests  the  idea  that  they  are  veritable  pro- 
longations of  the  cells,  of  which  they  have  usually  been  regarded  as  mere  appur- 
tenances;3 and  that  their  rhythmical  movement  is  to  be  regarded,  no  less  than 
the  changes  of  shape  in  entire  cells,  as  a  manifestation  of  cell-force  (§110).     It 
certainly  depends  upon  the  continued  vitality  of  the  cell,  and  is  affected  by 
agencies  which  tend  to  increase  or  to  repress  its  vigor.     And  the  fact  already 
mentioned  (§   113)  as  to  the  reciprocity  of  ciliary  movement  and  secretory 
action,  is  a  strong  indication  that  both  proceed  from  the  same  dynamical  source. 
It  has  been  maintained  by  some,  that  the  action  of  the  cilia  is  muscular ;  but 
these  filaments  are  usually  too  small  to  contain  even  the  minutest  fibrillse  of 
true  muscular  tissue ;  and  we  can  scarcely  but  regard  them  as  organs  sui  generis, 
which  do  not  owe  their  peculiar  endowments  to  any  other. 

233.  The  Epithelium  of  most  parts  of  the  surface  of  the  Mucous  Membranes 
appears  to  be  frequently  exuviated  and  renewed;  in  fact,  in  most  cases   in 
which  it  has  a  true  secretory  action,  that  action  is  completed  by  the  detach- 
ment of  the  epithelial  cells,  after  they  have  developed  themselves  at  the  expense 
of  the  peculiar  matter  which  they  have  drawn  from  the  blood ;  and  preparation 
is  soon  made  by  a  new  growth  for  a  repetition  of  the  secreting  process.     No 

1  "Gazette  Medicale,"  1851,  No.  26.     These  observations  were  made  at  the  Ecole  Prat- 
ique, on  the  body  of  a  decapitated  criminal. 

2  See  the  "Priiger  Vierteljahrschrift"  for  1851,  cited  in  the  "Edinb.  Monthly  Journ. ," 
Jan.  1852,  p.  82. 

3  This  is  certainly  the  case  with  regard  to  the  long  filamentous  processes  of  many  (so- 
called)  Animalcules,  which  only  differ  from  cilia  in  being  of  much  larger  size,  and  in  not 
being  multiple ;  between  the  two  forms,  however,  there  are  many  intermediate  gradations, 
so  that  the  similarity  of  their  nature  can  scarcely  be  doubted. 


238  OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 

very  positive  account  can  be  given,  of  the  mode  in  which  the  epithelial  cells 
originate,  but  there  are  appearances  which  indicate  that  it  is  not  always  the 
same.  Thus,  in  most  of  the  cases  in  which  a  spheroidal  epithelium  presents 
itself  as  the  active  instrument  of  secretion  (as,  for  instance,  on  the  villous 
prominences  of  the  synovial  membranes  (§  227),  its  cells  are  observed  to  be  in 
different  stages  of  development,  and  they  are  embedded  in  a  granular  blastema, 
in  which  it  appears  probable  that  they  may  originate  de  novo,  after  the  manner 
already  described  (§  106).  But  in  many  other  cases,  the  epithelial  cells  cover- 
ing an  extensive  tract  are  so  very  similar  to  one  another  in  form,  size,  and  grade  of 
development  (Fig.  25),  that  it  is  obvious  that  they  must  have  been  all  produced, 
and  all  brought  to  a  readiness  for  exuviation,  at  the  same  time ;  and  it  not 
unfrequently  happens,  more  especially  in  the  case  of  the  cylinder  epithelium  of  the 
intestinal  villi,  that,  when  detached  from  the  basement  membrane,  the  cells  are 
still  found  to  be  adherent  to  each  other,  and  to  carry  upon  their  broad  free  sur- 
face a  thin  membranous  pellicle  (a,  a),  which  may  be  made  more  distinct  by 
the  action  of  water.  Here  it  would  seem  more  likely  that  the  cells  are  de- 
veloped in  the  very  substance  of  the  basement  membrane,  perhaps  from  a  germi- 
nal spots"  contained  in  itself,  as  suggested  by  Prof.  Groodsir  (§  116) ;  and  that, 
in  the  course  of  their  enlargement,  they  carry  before  them  the  outer  layer  of 
the  basement  membrane  beneath  which  they  originated. — So,  again,  in  the  case 
of  the  secreting  follicles,  there  are  indications  that  the  cells  they  contain  are 
sometimes  developed  in  the  midst  of  a  blastema  exuded  from  their  walls; 
whilst  in  other  instances  the  origin  of  the  cells  seems  traceable  to  a  "  germinal 
spot"  at  the  caecal  extremity  of  the  follicle,  or  to  several  such  spots  dispersed 
over  its  sides.  Upon  the  whole  of  this  subject — the  conditions  under  which 
the  exuviation  of  the  Epithelium  occurs,  the  frequency  with  which  it  usually 
takes  place,  and  the  mode  in  which  its  renewal  is  effected — much  still  remains 
to  be  learned. 

234.  We  have  now  to  consider,  in  somewhat  mofe  detail,  certain  appendages 
to  the  Mucous  membranes,  which  are  found  in  connection  with  particular  parts 
of  them ;  and  which  may  be  considered  as  special  developments  of  their  ordi- 
nary elements. — Thus  in  the  mouth,  and  especially  on  the  tongue,  we  meet  with 
numerous  slight  elevations  or  papillae,  some  of  which  are  very  minute  and 
simple,  whilst  others  are  larger  and  more  complex,  being  cleft  (as  it  were) 
into  secondary  papillae.  The  intimate  structure  of  these  is  by  no  means 
uniform;  and  the  purposes  which  they  answer  are  probably  very  diverse. 
Thus,  whilst  the  "fungiform"  papillae  have  a  soft  epithelial  covering,  and 
are  copiously  supplied  with  bloodvessels  and  nerves,  so  as  to  serve  for  the  re- 
ception of  gustative  impressions,  the  "  conical"  are  furnished  with  a  firm  horny 
epithelial  investment,  sometimes  prolonged  into  fine  filaments,  and  are  less  copi- 
ously supplied  with  nerves  and  bloodvessels,  their  function  being  probably  the 
purely  mechanical  one  of  assisting  in  the  abrasion  and  comminution  of  the  food. 
It  is  curious  that  the  fungiform  papillae  contain  striated  muscular  fibres,  which 
pass  up  to  them  from  the  muscular  substance  of  the  tongue,  a  fact  first  an- 
nounced, in  regard  to  the  Frog,  by  Dr.  Edmund  Waller;1  and  that  they  under- 
go a  kind  of  erection  from  the  turgescence  of  their  vessels,  when  sapid  sub- 
stances are  brought  into  contact  with  them. — In  the  oesophagus  and  stomach, 
we  find  the  mucous  membrane  usually  lying  in  rugae  or  wrinkles,  which  are  dis- 
posed with  some  regularity ;  these,  however,  are  simple  folds  into  which  the 
membrane  is  thrown  by  the  contraction  of  the  muscular  coats  of  these  organs, 
and  are  obliterated  by  distension  of  the  latter.  A  permanent  series  of  folds, 
however,  which  can  only  be  obliterated  by  dividing  the  outer  coats  of  the  canal, 
are  found  in  the  small  intestine,  where  they  are  known  as  the  "valvulae  conni- 
ventes."  The  chief  use  of  these  appears  to  be  to  increase  the  absorbent  surface. 

1  "Philosophical  Transactions,"  1849,  p.  143. 


MUCOUS   MEMBRANES. 


239 


Fig.  27. 


Villi  of   the   Human    Intestine, 
with  their    capillary  plexus  in- 
jected. 


— The  mucous  surface  of  the  small  intestine,  from  the  pyloric  orifice  to  the 
csecum,  is  thickly  beset  with  vitti,  which  are  prolongations  of  the  basement 
membrane,  having  somewhat  the  form  of  the  finger 
of  a  glove,  copiously  furnished  with  bloodvessels 
from  the  subjacent  surface  (Fig.  27),  and  also  con- 
taining lacteal  tubules  in  their  interior.  In  form 
they  are  sometimes  nearly  cylindrical,  sometimes 
rather  conical,  and  not  unfrequently  become  flat- 
tened and  extended  at  the  base,  so  that  two  or  more 
coalesce.  Their  length  varies  from  l-4th  to  l-3d  of 
a  line,  or  even  more  ;  and  the  broad  flattened  kinds 
are  about  l-6th  or  l-8th  of  a  line  in  breadth.  In 
the  upper  part  of  the  small  intestine,  where  they  are 
most  numerous,  it  has  been  calculated  by  Krause 
that  there  are  not  less  than  from  50  to  90  in  a  square 
line ;  and  in  the  lower  part,  from  40  to  70  in  the 
same  space.  An  approach  to  the  villous  structure 
is  presented  by  the  portion  of  the  mucous  membrane 
of  the  stomach,  in  the  neighborhood  of  the  pylorus; 
but  the  prominences  which  are  here  found  between 
the  orifices  of  the  gastric  follicles,  are  much  smaller 
than  the  true  villi  of  the  intestine,  and  contain  no 
lacteal  vessels.  There  can  be  no  doubt  that  the  pro- 
per intestinal  villi  are  the  chief  instruments  of  absorption,  by  means  both  of 
their  bloodvessels,  which  take  up  soluble  matters  by  simple  imbibition,  and  of 
their  lacteals,  which  absorb  certain  special  products  of  the  digestive  operation. 
In  the  selection  of  these,  it  will  be  hereafter  shown  that  the  epithelial  cells  of 
the  villi  are  the  instruments  chiefly  concerned;  these  filling  themselves  with 
the  materials  of  chyle  from  the  contents  of  the  alimentary  canal  (Fig.  134),  and 
then  delivering  them  up  to  be  absorbed  by  the  lacteals  beneath  (CHAP.  vin. 

SECT.  1). 

235.  The  inversion  of  the  mucous  surface  into  follicles,  gives  to  it  a  character 
precisely  the  reverse  of  the  preceding,  both  as  regards  structure  and  function. 
These  follicles,  in  their  most  elementary  form,  may  be  regarded  as  originating 
in  a  recession  of  the  basement  membrane  (as  if 
the  finger  of  a  glove  were  pushed  back  into  the 
interior  of  the  palm)  ;  they  are  nearly  of  a  cylin- 
drical shape,  their  orifices  opening  upon  the  free 
surfaces  of  the  mucous  membrane  in  the  inter- 
spaces of  the  vascular  network  (Fig.  28), 
while  their  csecal  extremities,  which  are  some- 
times simply  rounded,  sometimes  loculated,  abut 
against  the  submucous  areolar  tissue.  Such  fol- 
licles present  themselves  along  the  whole  extent 
of  the  gastro-intestinal  mucous  membrane;  but 
although  very  similar  in  their  appearance  in  dif- 
ferent parts  of  its  length,  their  secretion  is  pro- 
bably very  different.  In  the  stomach  they  are  known  as  the  "  gastric  follicles," 
and  the  digestive  solvent  is  prepared  and  poured  forth  by  them.  Along  the 
course  of  the  intestine,  on  the  other  hand,  they  are  known  as  the  "  follicles  of 
Lieberkuhn ;"  and  it  is  doubtful  whether  they  form  any  other  secretion  than 
that  of  protective  mucus.  Such  follicles  are  not  known  to  exist  in  any  other 
than  the  open  state ;  and  they  seem  to  have  a  permanent  character,  continually 
discharging  new  broods  of  epithelial  cells.  The  secreting  action  of  these  folli- 
cles may  be  best  observed  in  those  of  the  stomach ;  which  during  the  intervals 


Fig.  28. 


Distribution  of  Capillaries  around  folli- 
cles of  Mucous  Membrane. 


240 


OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 


of  the  digestive  process,  become  turgid  with  cells,  that  accumulate  in  such 
quantity,  as  to  give  to  the  tubes  a  sacculated  appearance  which  they  do  not  possess 
when  empty;  within  the  principal  cells,  smaller  ones  are  frequently  observable, 
and  even  a  second  brood  may  be  sometimes  seen  in  the  interior  of  the  latter;1 
and  when  digestion  is  going  on,  these  cells  are  poured  out  in  large  numbers  on 
the  surface  of  the  mucous  membrane,  where  they  undergo  a  kind  of  deliques- 
cence by  the  imbibition  of  water,  and  form  the  substance,  indefinitely  termed 
mucus,  which  probably  contains  the  "  ferment"  that  is  the  essential  accompani- 
ment of  the  acid  solvent  in  the  process  of  gastric  digestion. — Besides  these  folli- 
cles, however,  which  are  by  no  means  peculiar  to  the  lining  of  the  alimentary 
canal,  the  gastro-intestinal  mucous  membrane  contains  numerous  other  simple 
glandulse,  which  afford  links  of  transition  towards  those  more  complicated  forms 
of  the  glandular  apparatus  that  are  less  intimately  connected  with  it.  Reserv- 
ing a  more  particular  description  of  these  for  a  future  opportunity  (CHAPS,  vii. 
and  xni.),  we  shall  here  only  notice  the  points  that  bear  upon  the  essential 
nature  of  Glands  in  general.  Various  parts  of  the  mucous  membrane  of  the 
stomach,  and  of  the  large  intestine,  are  studded  at  intervals  with  shallow  pits  or 
follicles,  about  l-20th  of  an  inch  in  diameter;  which,  according  to  the  observa- 
tions of  Dr.  A.  Thomson  (loc.  cit.),  have  the  form  of  closed  vesicles  during  foetal 
life  and  early  infancy,  but  gradually  open,  so  that  their  cavities  become  continu- 
ous with  the  free  surface  of  the  mucous  membrane,  the  columnar  epithelium  of 
which  extends  itself  into  them ;  and  they  remain  in  that  condition  during  the 
rest  of  life.  What  their  distinctive  attribute  may  be,  however,  has  not  been 
made  out. — The  mucous  lining  of  the  small  intestine  is  beset  at  intervals  with 
elevated  patches,  which  are  known  under  the  name  of  the  "  agminated  glands  of 
Peyer."  These  are  formed  by  the  aggregation  of  originally-closed  vesicles  of  a 
somewhat  lenticular  shape,  which  lie  just  beneath  the  mucous  membrane,  their 
own  walls  being  closely  incorporated,  at  the  deeper  side,  with  the  subjacent  fila- 
mentous tissue;  and  they  are  filled  with  cells  and  granular  particles  in  various 
stages  of  development.  It  seems  probable  from  the  observations  of  Profs.  Krause 
and  Allen  Thomson,  that  these  vesicles  are  continually  opening  and  discharging 
their  contents  upon  the  mucous  surface;  each,  when  it  has  completely  emptied 
itself,  becoming  atrophied,  and  being  replaced  by  another.  These,  also,  are  appa- 
rently to  be  looked  upon  as  secreting  organs ;  but  they  can  scarcely  be  considered 

in  any  other  light  than  as  parent-cells, 


Fig.  29. 


Portion  of  one  of  Srunner's  Glands,  from  the  Human 
Duodenum.    Magnified  65  diameters. 


developed  in  the  substance  of  the  tis- 
sues quite  independently  of  the  mucous 
surface,  with  which  they  only  become 
connected  for  the  purpose  of  giving  exit 
to  their  contents.  Such,  it  is  probable, 
is  the  original  state  of  the  elements  of 
most  of  the  more  complex  glandular 
structures ;  the  essential  part  of  them 
seeming  to  consist  of  a  collection  of 
glandular  vesicles,  which  are  originally 
closed  (a  condition  that  is  retained  in 
the  thyroid  throughout  life),  but  which 
afterwards  come  into  connection  with 
the  mucous  or  cutaneous  surface  where- 
on they  discharge  their  secretion,  by 
an  extension  of  an  offset  from  the  lat- 
ter, that  constitutes  the  ramifying 
ducts  on  which  they  open.  A  simple 


1  Dr.  Allen  Thomson,  in  Goodsir's  "Annals  of  Anatomy  and  Physiology,"  No.  I.  p.  36. 


THE    SKIN. ITS   PAPILLA   AND    GLANDULE. 


241 


type  of  this  more  complex  glandular  apparatus  is  presented  to  us  in  those  small 
bodies  peculiar  to  the  duodenum,  which  are  known  as  "  Brunner's  glands."  (Fig. 
29.)  The  terminal  vesicles  of  these  racemose  clusters  are  loaded  with  cells 
formed  in  their  interior,  the  aspect  and  mode  of  production  of  which  are  quite 
different  from  those  of  an  epithelium.  This  will  be  better  understood  from  the 
succeeding  figure  (Fig.  30),  which  represents  one  of  the  terminal  caeca  of  the 
liver  of  the  Crab  j  this  is  seen  to  be  crowded  with  cells,  which  not  only  line  its 
internal  surface,  but  fill  its  cavity ;  and  the  cells  are  observed  to  originate  in 
the  midst  of  an  indistinct  granular  matter  that  occupies  the  deeper  portion  of 
the  follicle,  increasing  in  size  and  completeness  as  they  are  pushed  towards  its 
outlet  by  newer  growths  beneath.  In  most  glands,  an  unlimited  production  of 
cells  appears  to  take  place  continuously  within  the  same  follicles  ;  the  cases  in 
which  the  follicles  shrivel  and  dwindle  away,  when  they  have  once  opened  them- 
selves and  discharged  their  contents,  being  comparatively  few. — All  glandular 
structures  require  a  copious  supply  of  blood,  to  fur- 
nish the  materials  of  the  secretion  which  they  elimi-  Fig-  30- 
nate  ;  and  this  is  afforded  by  a  minute  capillary  ^  $ 
network,  which  closely  surrounds  the  follicles  or 
vesicles,  but  which  never  penetrates  their  interior 
(Fig.  31.) 

Fig.  81. 


Onc  of  the  hepatic  cseca  of 
«.#?««  (Cray  fish),  highly  magnified, 
showing  the  progress  of  development 

of  the  secreting  cells  from  tlie  blind 


Capillary  Network    around  the    follicles 
of  Parotid  Gland. 

236.  The  Skin.  —  Like  the  Mucous  Membranes 
with  which  it  is  continuous  at  the  nose,  mouth, 
anus,  and  the  other  orifices  of  the  canals  which 
these  line,  the  Skin  may  be  considered  as  composed 
of  three  elements;  namely,  the  complex  fibrous 
tissue,  which,  with  bloodvessels,  lymphatics,  and 
nerves  makes  up  the  Cutis  vera  or  Corium  ;  a  layer 
of  Basement  membrane  investing  this,  and  an  epi- 
thelial  investment  of  peculiar  thickness  and  tena- 
city,  which  is  known  a.  i^  Epidermis  or  "cuti- 

Cle.    -  Ihe  Substance  OI    the  Cormm  IS    principally 

composed  of  White  fibrous  tissue,  which  is  arranged 
in  a  reticular  manner  ;  the  texture  being  very  fine 
and  close  near  the  surface,  but  more  open  in  its  deeper  layers,  where  its  areolse 
become  occupied  with  clumps  of  fat-cells,  and  where  it  passes,  without  any  dis- 
tinct line  of  separation,  into  that  of  the  subcutaneous  Areolar  tissue.  With 
this  white  fibrous  tissue,  a  small  proportion  of  yellow  or  elastic  fibres  is  usually 
intermixed  ;  and  this  proportion  is  greatly  increased  in  those  parts  of  the  skin 
which  are  subject  to  occasional  distension,  and  especially  in  the  integument  sur- 
rounding the  joints.  ^  The  Cutis,  however,  not  only  possesses  elasticity;  but  is 
also  endowed  with  vital  contractility,  which  is  peculiarly  manifest  in  particular 
parts,  especially  under  the  influence  of  cold  or  of  mental  emotion  ;  producing 
16 


cesgive  stages,  are  shown  separately 

at  a,  6,  c,  d,  e. 


242  OF   THE   PRIMARY   TISSUES    OF   THE   HUMAN   BODY. 

the  corrugation  of  the  integuments  of  the  scrotum,  and  that  peculiar  condition 
of  the  general  surface  which  is  known  as  the  "cutis  anserina."  The  real  nature 
of  its  contractile  element,  however,  has  only  been  recently  discovered  by  Prof. 
Kblliker;  who  has  found  it  to  consist  of  "smooth"  or  non-striated  muscular 
fibre-cells  (Fig.  99),  which  are  united  into  fasciculi,  and  dispersed  among  the 
other  elements  of  the  cutaneous  substance.  They  are  especially  abundant  in 
the  deeper  part  of  the  cutis  of  the  scrotum,  where  they  form  a  reticular  layer 
which  is  known  as  the  "tunica  dartos;"  and  also  in  the  skin  of  the  penis  and 
perineum,  as  well  as  in  the  nipple  and  areola.  In  other  parts  of  the  integu- 
ment, they  are  especially  connected  with  the  hair-follicles ;  and  where  these  are 
wanting,  as  on  the  palms  of  the  hands  and  soles  of  the  feet,  there  are  no  muscu- 
lar fibre-cells.  In  the  production  of  the  "  cutis  anserina,"  which  may  be  artifi- 
cially induced  by  the  application  of  the  magneto-electric  apparatus,  these  fibres 
cause  the  protrusion  of  the  hair-follicles,  while  they  retract  and  depress  the 
intermediate  cutaneous  surface.1 

237.  The  external  surface  of  the  Corium  is  elevated  in  many  parts  into 
papillae  or  ridges,  which,  though  representing  the  villi  of  mucous  membranes, 
have  an  entirely  different  office ;  their  special  function  being  usually  to  receive 
tactile  impressions  through  the  medium  of  the  nerves  with  which  they  are  fur- 
nished, their  size  and  number  being  proportional  to  the  acuteness  of  the  sensi- 
bility possessed  by  different  parts  of  the  surface.  In  general,  the  papillae  are 
simple  conical  projections,  the  length  of  which  is  from  about  l-33d  to  l-22d  of 
a  line ;  but  on  the  palm,  sole,  and  nipple,  they  are  mostly  compound  (that  is, 
they  have  several  distinct  summits),  and  measure  from  l-20th  to  l-10th  of  a  line 
in  length.  In  these  last  situations,  they  are  set  very  closely  together  in  curvi- 
linear ridges,  which  are  marked  at  tolerably  regular  intervals  by  short  transverse 
furrows,  into  each  of  which  the  orifice  of  one  of  the  sweat-glands  discharges 
itself.  On  some  parts  of  the  surface,  however,  the  papillae  are  altogether  want- 
ing; and  in  the  matrix  of  the  nail,  where  they  are  as  large  and  numerous  as  on 
the  palms  of  the  hands,  they  serve  an  entirely  different  purpose,  that  of  afford- 
ing a  more  extended  surface  for  the  production  of  epidermic  cells.  The  base- 
ment membrane  may  be  tolerably  well  made  out  by  the  definite  boundary  which 
it  affords  to  the  components  of  the  papillae ;  but  it  is  not  distinguishable  in  a 
like  degree  on  the  general  surface  of  the  Corium;  and  its  presence  there  can  only 
be  inferred  from  analogy,  and  from  the  existence  of  a  fine  film  in  that  situation 
in  the  embryo. — The  surface  of  the  Corium  likewise  presents  numerous  depres- 
sions, which  are  sometimes  mere  follicles,  but  sometimes  tubuli  of  considerable 
length.  All  these  depressions  are  lined  by  cells,  which  are  continuous  with  those 
of  the  Epidermis ;  but  the  function  of  these  cells  is  very  different  in  the  several 
varieties  of  the  follicular  organs.  Thus,  in  the  Hair-follicles,  we  find  them 
undergoing  transformation  into  the  substance  of  the  hair,  which  is  chemically 
identical  with  that  of  the  Epidermis  itself;  in  the  Sebaceous  follicles,  on  the  other 
hand,  they  draw  fatty  matter  from  the  blood,  and  set  free  this  upon  the  surface 
of  the  skin ;  in  the  Cerumen-glands,  they  elaborate  a  waxy  matter,  which  they 
discharge  on  the  integument  lining  the  meatus  of  the  ear ;  in  the  Sudoriparous 
glandulae,  with  which  nearly  every  part  of  the  surface  is  furnished,  they  are  the 
instruments  of  drawing  off  a  large  amount  of  watery  fluid,  which  holds  in  solu- 
tion a  small  proportion  of  effete  organic  compounds;  and  in  the  peculiar  large 
sudoriparous  glandulae  of  the  axillae,  they  further  seem  to  eliminate  from  the 
blood  the  peculiar  Odorous  secretion  which  is  characteristic  of  that  part.3  The 
Hair-follicles  will  be  presently  described  in  connection  with  the  Epidermis  (§  246) ; 

1  See  Prof.  Kolliker's  Memoir  on  the  "Smooth  Muscular  Fibre,"  in  "Kolliker  and  Sei- 
bold's  Zeitschrift,"  1849;  and  his  "  Mikroskopische  Anatomic,"  band  ii.  pp.  13,  14. 

'  See  Prof.  Horner  in  the  "  Amer.  Journ.  of  Med.  Sci.,"  Jan.  1846  ;  and  M.  llobin,  in 
the  "Ann.  des  Sci.  Nat.,"  3ieme  eer.,  Zool.,  torn.  iii.  p.  380. 


SEBACEOUS   AND   CUTANEOUS   GLANDULJE 


243 


but  a  short  account  of  the  structure  and  development  of  the  other  cutaneous 
glandulse  will  here  be  given,  as  further  elucidating  the  nature  of  the  glands  in 
general,  and  as  connected  with  the  special  functions  of  the  Skin. 

238.  The  Sebaceous  glandulse  are  for  the  most  part  found  in  connection  with 
the  Hair-follicles,  and  pour  their  secretion  into  the  hair-canals  near  their  orifices 
(Fig.  32).  They  are  usually  composed  of  clusters  of  secreting  sacculi,  lined 

Fig.  82. 


Sebaceous  Glands,  showing  their  size  and  relation  to  the  hair-follicles  :  A  and  B  from  the  nose;  c  from  the 
beard.    In  the  latter,  the  cutis  sends  down  an  investment  of  the  hair  follicles.— Magn.  18  diam. 

A  Fig.  33. 


Cutaneous  Glandulao  of  external  meatus  auditorius:  A,  section  of  the  Cutis,  magnified  three  diameters;  2.  2. 
hairs ;  3. 3.  superficial  sebaceous  glands ;  1. 1.  larger  and  deeper-seated  glands,  by  which  the  cerumen  is  secreted, 
u,  a  Lair,  perforating  the  epidermis  at  3. ;  1. 1.  sebaceous  glands,  with  their  excretory  ducts  2.  2. ;  4.  base  of 
the  hair,  in  its  double  follicle  5.  5.  c,  cerumen-gland,  formed  by  the  contorted  tube,  1.1.  of  the  excretory 
duct,  2  ;  4,  vascular  truuk  and  ramifications.  The  last  two  figures  highly  magnified. 


244 


OF   THE    PRIMARY    TISSUES    OF    THE    HUMAN   BODY. 


with  epithelium-cells,  which,  being  filled  with  fatty  matter,  resemble  the  cells 
of  adipose  tissue ;  the  number  of  these  sacculi  generally  varies  from  four  or  five 
to  twenty,  but  in  rare  cases  it  is  reduced  to  three,  two,  or  even  one.  The  size 
of  these  glandulae,  and  the  number  which  open  into  the  same  hair-follicle,  bear 
no  proportion  to  the  size  of  the  hair;  but  are  rather  related  to  the  necessity 
which  may  exist,  on  the  several  parts  of  the  surface,  for  their  lubrifying  secre- 
tion. Some  of  the  largest  of  them  are  found  in  connection  with  the  fine  downy 
hairs  of  the  nose  and  of  other  parts  of  the  face;  and  their  orifices  being  often 
obstructed  by  particles  of  foreign  matter,  they  become  distended  with  their  adi- 
pose secretion,  and  not  unfrequently  afford  the  nidus  to  a  curious  parasite,  which 
seems  to  belong  to  the  Arachnidan  class,  and  is  not  known  to  exist  elsewhere.1 
— The  development  of  the  Sebaceous  glandulae,  which  has  been  recently  made 
the  subject  of  careful  study  by  Prof.  Kolliker,2  commences  at  about  the  sixth 
month  of  foetal  life,  in  a  sort  of  excrescence  of  the  cellular  lining  (root-sheath) 
of  the  hair-follicle  (Fig.  34,  A,  d)t  which  is,  in  fact,  a  continuation  of  the 

Fig.  34. 


Development  of  the  Sebaceous  Glands,  in  connection  with  the  hair-follicle?,  from  a  Foetus  of  six  months ; 
A,  incipient  development  of  the  glandular  papilla,  from  the  cells  of  the  outer  root-sheath ;  B,  the  same,  hav- 
ing assumed  the  flask-shape,  and  showing  the  first  appearance  of  fat-cells  in  its  interior ;  c,  extension  of  the 
formation  of  fat-cells  through  the  pedicle,  and  their  expulsion  into  the  hair-canal ;  a,  hair ;  ft,  inner  root- 
sheath  ;  c,  outer  root-sheath  ;  d,  incipient  sebaceous  glands. 

deeper  portion  of  the  Epidermis  (§  241).  Each  of  these  little  processes,  which 
is  at  first  solid,  soon  assumes  somewhat  of  a  flask-shape,  through  the  narrowing 
of  its  neck  (B,  d) ;  but  as  its  development  advances,  a  group  of  cells  containing 
fat-particles  appears  in  its  centre,  and  gradually  extends  itself  along  the  axis  of 
the  pedicle,  until  it  penetrates  through  the  root-sheath  (c);  and  the  fat-cells  thus 
escape  into  the  cavity  of  the  hair-follicle,  and  constitute  the  first  secretion  of 
the  sebaceous  gland.  They  are  soon  succeeded  by  others  of  the  same  kind,  and 
the  little  gland  is  established  in  its  office ;  additional  sacculi  and  recesses  being 
subsequently  formed  by  the  budding-out  of  its  cellular  lining,  as  the  first  was 
produced  by  out-growth  from  the  root-sheath.  The  purpose  of  the  Sebaceous 
secretion  is  to  keep  the  Skin  from  being  dried  and  cracked  by  the  action  of  heat 
and  of  air,  and  thus  to  maintain  its  flexibility;  and  also  to  diminish  the  friction 
between  those  parts  of  the  surface  which  move  one  over  another.  Hence  we 
find  it  especially  abundant  on  the  integument  of  the  face  and  head,  which  is 
necessarily  more  exposed  than  that  of  any  other  part  to  the  sun  and  atmosphere; 

1  See  Dr.  Gustav.  Simon,  in  "  Muller's  Archiv.,"  1842;  Mr.  Erasmus  Wilson,  in  "Philos. 
Transact.,"  1844,  and  "Healthy  Skin,"  3d  edit.  pp.  50-53;  and  Prof.  Owen's  "Lectures 
on  Comparative  Anatomy,"  vol.  i.  p.  252. 

2  " Mikroskopische  Anatomic,"  band  ii.  pp.  192-196. 


THE   CUTIS. 


245 


Sweat-gland  and  the  commencement  of  its  duct : 
a.  Venous  radicles  on  the  wall  of  the  cell  in  which 
the  gland  rests.  This  vein  anastomoses  with 
others  in  the  vicinity,  b.  Capillaries  of  the  gland 
separately  represented,  arising  from  their  arteries, 
which  also  anastomose.  The  bloodvessels  are  all 
situated  on  the  outside  or  deep  surface  of  the  tube, 
in  contact  with  the  basement  membrane. — Magn. 
35  diam. 


and  also  in  the  neighborhood  of  the  joints.  Its  amount  is  peculiarly  great  in  the 
races  which  are  formed  to  inhabit  warm 
climates ;  and  it  is  probable  that  habitual 
exposure  of  the  surface  generally  would 
considerably  augment  the  quantity  of 
unctuous  matter  poured  forth  for  its  lubri- 
cation.— The  Sudoriparous  glandulae  es- 
sentially consist  of  long  convoluted  tubes 
(Fig.  35),  which,  however,  are  rarely 
single,  but  are  multiplied  by  repeated  di- 
chotomous  subdivision,  sometimes  also  giv- 
ing off  short  caecal  processes  before  their 
termination.  These  are  seated  rather 
beneath  the  Corium,  in  the  midst  of  the 
subcutaneous  adipose  tissue,  than  in  the 
substance  of  the  skin  itself.  All  the  tu- 
buli  of  each  gland  unite  so  as  to  form  but 
one  duct;  and  this  passes  upwards  through 
the  Cutis  and  Cuticle,  in  a  somewhat 
corkscrew-like  manner,  to  open  upon  the 
surface  of  the  latter,  which  it  usually 
reaches  obliquely,  so  that  the  outer  layer 
of  the  Epidermis  forms  a  sort  of  little 
valve,  which  is  lifted  by  the  secreted  fluid 
as  it  issues  forth.  The  Ceruminous 
glandulae  of  the  meatus  auditorius  (Fig. 
83,  c),  and  the  Odoriferous  glandulae 
of  the  axilla,  are  mere  local  varieties  of  the  ordinary  sudoriparous;  correspond- 
ing with  them  in  structure,  but  differing  in  the  character  of  their  secretion. 
The  development  of  all  these  glandulae  seems,  according  to  the  observations  of 
Prof.  Kolliker  (Op.  cit.,  pp.  167-172),  to  commence  very  much  after  the  fashion 
of  that  of  the  hair-follicles  (§  247) ;  namely,  by  a  knob-like  projection  of  the 
deeper  layer  of  the  Epidermis,  which  is  received  into  a  hollow  of  the  Cutis. 
This  gradually  elongates,  so  as  to  penetrate  deeper  and  deeper  into  the  skin  ; 
and  a  cavity  is  formed  along  its  axis,  which,  though  at  first  destitute  of  an  out- 
let, gradually  reaches  to  the  surface;  whilst  at  the  same  time,  the  deeper  portion 
becomes  coiled  upon  itself,  and  the  number  of  tubes  increases  by  out-growth 
from  the  one  first  formed.  The  secretory  action  of  these  glandulae  has  reference 
rather  to  the  wants  of  the  economy  in  general,  than  to  the  special  functions  of 
the  skin;  and  it  will,  therefore,  be  more  appropriately  considered  hereafter 
(CHAP.  xn.  SECT.  4). 

239.  The  Cutis  is  very  copiously  supplied  with  Bloodvessels,  which  distribute 
blood,  through  capillary  plexuses  of  great  minuteness,  to  the  sweat-glands,  hair- 
follicles,  and  fat-clumps  of  its  deeper  portion,  and  then  form  a  dense  network 
near  its  surface,  from  which  looped  branches  are  sent  up  into  the  papillae,  the 
distribution  of  these  last  being  nearly  the  same  whether  the  papillae  are  en- 
dowed with  tactile  sensibility,  or  are  subservient  to  the  formation  of  the  nail- 
substance.1  The  Lymphatics  of  the  skin,  also,  are  very  numerous,  and  form 
minute  plexuses  near  the  surface.  A  copious  supply  of  Nerves,  too,  is  sent  to 
the  skin ;  especially  to  such  parts  of  it  as  are  thickly  set  with  tactile  papillae ; 

1  It  is  a  curious  circumstance  that  the  under  surface  of  the  Dog's  foot  has  a  set  of 
large  composite  papillae,  that  are  concerned  in  the  formation  of  its  thick  cuticular  invest- 
ment ;  which,  so  far  as  the  arrangement  of  their  vessels  is  concerned,  closely  resemble 
those  of  the  fungiform  papillge  of  the  tongue. 


246  OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 

these  form  a  minute  plexus  through  the  whole  substance  of  the  skin,  which 
becomes  finer  and  closer  as  it  approaches  the  surface,  its  branches  at  length  coin- 
ing to  contain  but  one  or  two  fibres  each ;  and  from  the  most  superficial  portion 
of  the  plexus,  fibres  pass  up  into  the  papillae,  which  there  terminate  in  loops.1 — 
Thus  we  see  that  the  Vascularity  of  the  skin  has  purposes  very  different  from 
those  which  it  answers  in  the  Mucous  membranes ;  a  large  part  of  the  blood 
which  this  tissue  receives,  being  destined  to  afford  to  the  nerves  of  Touch  the 
means  of  their  activity;  and  one  chief  office  of  the  remainder  being  to  supply 
the  material  for  the  production  of  the  protective  Epidermis  and  its  appendages. 
It  is  only  in  the  excretory  action  of  the  Sudoriparous  glandulae,  and  in  the  slight 
absorptive  power  which  the  Skin  possesses,  that  we  trace  any  functional  relation 
to  the  great  Mucous  membrane  system.  The  Skin,  in  fact,  ministers  almost  as 
exclusively  to  the  operations  of  Animal  life,  as  do  the  Mucous  Membranes  to 
that  of  Organic  life. — The  nutrition  of  the  various  textures  composing  the  Skin 
may  be  considered  to  take  place  with  an  activity  proportionate  to  their  several 
requirements;  thus,  whilst  the  various  glandular  organs,  the  hair-follicles,  the 
nervous  papillae,  and  the  muscular  fibres,  are  continually  drawing  new  elements 
from  the  blood,  it  is  probable  that  the  fibrous  tissues  which  constitute  the  essen- 
tial basis  of  this  texture  are  not  more  rapidly  renewed  than  they  are  elsewhere 
(§  220).  The  regeneration  of  the  skin,  after  the  loss  of  a  portion  of  it  by  dis- 
ease or  injury,  is  effected  with  almost  entire  completeness.  The  new  tissue  is  at 
first  more  dense  and  less  vascular  than  the  old;  but  it  soon  gives  such  indications 
of  sensibility  as  make  it  evident  that  nerve-fibres  must  be  very  early  formed,  in 
its  substance;  and  the  epidermis  is  normally  developed  from  its  surface.  It  has 
been  asserted  that  no  tactile  papillae  are  ever  formed  upon  regenerated  skin,  and 
that  in  the  Negro  the  pigment-cells  are  not  reproduced,  so  that  the  cicatrix 
remains  light.  Neither  of  these  statements,  however,  is  correct;  though  it  is 
quite  true  that  some  time  elapses  before  the  pigment-cells  of  the  Negro  epider- 
mis are  formed  again  in  their  usual  amount.  It  is  not  yet  certain  that  the  hair- 
follicles  and  sudoriparous  glands  are  formed  in  regenerated  skin. 

240.  The  Epidermis  usually  forms  a  thin  semi-transparent  pellicle,  in  close 
apposition  with  the  surface  of  the  Cutis,  filling  up  the  spaces  between  its  papillae, 
so  as  to  obliterate  its  inequalities,  and  investing  the  whole  with  a  stratum  of 
nearly  uniform  thickness  (Figs.  37,  38);  so  that  whilst  its  under  side  is  pitted 
for  the  reception  of  the  cutaneous  papillae,  its  outer  or  free  surface  is  nearly 
level.  In  some  parts,  however,  the  Epidermis  is  enormously  increased  in  thick- 
ness; such  being  particularly  the  case  with  those  spots  which  are  subjected  to 
continual  pressure  or  friction,  such  as  the  palms  of  the  hands  and  the  soles  of 
the  feet.  Its  substance  consists  of  a  series  of  flattened  scale-like  cells,  which, 
when  first  formed,  are  spheroidal,  but  which  gradually  dry  up,  their  nuclei 
also  at  last  disappearing.  These  form  several  layers,  of  which  the  deeper  can 
be  seen  very  distinctly  to  possess  the  cellular  character,  whilst  the  external  layers 
are  scaly;  and  between  these,  all  stages  of  transformation  may  be  traced  (Fig. 
36) — the  outer  layers  being  continually  thrown  off  by  desquamation,  whilst  new 
ones  are  as  constantly  being  formed  below.  The  outer  and  inner  portions  of 
the  Epidermis,  however,  present  a  marked  difference  in  character  which  is 
made  still  more  apparent  by  the  use  of  reagents ;  for  whilst  the  former  (Fig. 
37,  a)  is  a  comparatively  firm  horny  membrane,  which  is  not  affected  either  by 
acetic  acid,  or  by  a  moderately  strong  solution  of  potash,  the  latter  is  soft  and 

1  The  existence  of  this  mode  of  termination  of  the  Nerve-fibres,  first  admitted  on  the 
Authority  of  Gerber,  and  confirmed  by  Purkinje  and  Krause,  but  looked  for  in  vain  by 
other  equally  competent  observers,  has  been  lately  established  by  Prof.  Kolliker  ("Mikro- 
skopische  Anatomic,"  band  ii.  pp.  24-31),  who  states  that  it  may  be  traced  with  com- 
parative ease,  if  the  skin  be  first  steeped  in  a  weak  solution  of  caustic  soda. 


THE    EPIDERMIS. 


247 


deficient  in  tenacity,  and  is  dissolved  (or  at  least  reduced  to  an  apparently  struc- 
tureless condition)  when  treated  with  either  of  these  liquids.     They  are  fur- 


Fig.  36. 


Fig.  37. 

t 


Vertical  section  of  Epidermis,  from  palm 
of  the  hand :  a,  outer  portion,  composed  of 
flattened  scales ;  b,  inner  portion,  consisting 
of  nucleated  cells ;  c,  tortuous  perspiratory 
tube,  cut  across  hy  the  section  higher  up- 
Magnified  155  diameters. 


Vertical  section  of  the  Skin  of  the  Thumb, 
showing  the  Epidermis  and  outer  layer  of  the 
Corium;  treated  with  acetic  acid:  a,  horny 
layer  of  Epidermis ;  b,  mucous  layer ;  c,  cutis 
vera ;  d,  single  papilla ;  e,  composite  papilla ;  /, 
epithelium  of  the  perspiratory  duct,' continuous 
with  the  mucous  layer  of  the  epidermis;  g, 
canal  of  the  same  through  the  cutis;  h,  its 
passage  through  the  horny  portion ;  i,  perspi- 
ratory pore. 


ther  distinguished  in  the  operation  of  vesicating 
agents;  for  the  fluid  which  they  cause  to  be 
effused  from  the  vessels  of  the  cutis,  raises 
little  else  than  the  outer  horny  layer  of  the 
cuticle,  as  it  passes  readily  through  the  softer 
tissue  beneath.  The  internal  layer  of  the 
cuticle  (Fig.  37,  5)  was  formerly  supposed  to 
be  a  distinct  structure,  and  was  termed  the  rete 
mucosum  or  stratum  Malpighii;  it  is  now  well 
known,  however,  to  be  chiefly  formed  by  the 
younger  portion  of  the  epidermis,  whose  cells 
are  not  yet  consolidated  by  the  formation  of 
horny  matter  in  their  interior.  In  immediate 
contact  with  the  basement  membrane  of  the 
cutaneous  papillae,  however,  there  is  usually 
found  a  layer  of  elongated  cells,  resembling 
those  of  columnar  epithelium,  arranged  perpen- 
dicularly to  the  surface  of  the  corium  (Fig.  38, 
5,  &) ;  sometimes  two,  or  even  three  strata  of 
such  cells  present  themselves.  They  are  ob- 
viously different  in  character  from  those  of  the 
superjacent  layers,  for  they  resist  the  action  of 
a  solution  of  potash  that  is  strong  enough  to 


Fig.  38. 


Vertical  section  of  the  Slan  of  the  Thigh 
of  a  Negro,  more  highly  magnified  :  a,  a,  a, 
three  papillae  of  the  Cutis;  b,  b,  deepest 
layer  of  columnar  cells,  deeply  colored ;  c, 
spheroidal  colls  filling  up  the  spaces  be- 
tween the  papilUe,  still  dark ;  d,  upper  more 
faintly-colored  portion  of  the  mucous  layer 
of  the  epidermis ;  e.  horny  layer,  with 
scarcely  any  perceptible  color. 


248  OF   THE   PRIMARY    TISSUES   OF   THE    HUMAN    BODY. 

dissolve  the  latter,  though  they  are  themselves  dissolved  by  a  stronger  solution, 
which  does  not  act  upon  the  horny  layer  of  the  cuticle  ;*  and  it  seems  not  improba- 
ble that  these  permanently  retain  their  place,  and  are  not  successively  carried  to 
the  surface  by  the  formation  of  new  layers  beneath,  as  are  the  spheroidal  cells 
(Fig.  38,  c,  d)  which  lie  upon  them.  In  what  way  these  spheroidal  cells  originate, 
has  not  yet  been  ascertained.  It  has  been  generally  supposed  that  they  are 
formed  upon  free  nuclei  in  the  midst  of  a  blastema  that  intervenes  beneath  the 
cutis  and  the  "  stratum  Malpighii;"  but  the  researches  of  Prof.  Kolliker  tend 
to  negative  this  idea,  and  to  render  it  probable  that  they  multiply  by  endogen- 
ous production.3  In  whatever  mode  they  are  generated,  the  nutriment  which 
they  require  for  their  growth  and  development  must  be  drawn  from  the  vessels 
of  the  Cutis,  through  the  medium  of  the  basement  membrane;  since,  however 
thick  may  be  the  substance  of  the  Epidermis,  it  is  never  penetrated  by  vessels. 
The  Epidermis  is  pierced  by  the  excretory  ducts  of  the  sebaceous  and  sweat- 
glands,  those  of  the  latter  passing  through  it  with  a  somewhat  corkscrew-like 
turn  (Fig.  37,  gy  i)}  and  both  being  lined  with  an  epithelium  (/)  which  is  con- 
tinuous with  that  of  the  mucous  layer  of  the  cuticle.  It  is  also  pierced  by  the 
Hairs,  with  whose  substance  (as  we  shall  presently  see)  it  has  a  like  relation  of 
continuity  through  their  follicles.  The  horny  layer  has  the  same  chemical  com- 
position with  Nails,  Hoofs,  Horns,  Hair,  and  Wool;  the  formula  of  all  of  them, 
being  480,  39H,  7N,  180. 

241.  The  Epidermis  covers  the  whole  exterior  of  the  body,  not  excepting 
the  Cornea  and  the  Conjunctival  membrane,  where,  however,  it  has  more  the 
character  of  an  Epithelium ;  this  -continuity  is  well  seen  in  the  cast  skin  or 
slough  of  the  Snake,  in  which  the  covering  of  the  front  of  the  eye  is  found  to  be 
as  perfectly  exuviated   as  that  of  any  part  of  the   surface.     The  Epidermis 
appears  solely  destined  for  the  protection  of  the  true  Skin,  from  the  mechanical 
injury  and  the  pain  occasioned  by  the  slightest  abrasion,  and  from  the  irritating 
influence  of  exposure  to  air  and  of  changes  of  temperature  :  we  perceive  the 
value  of  this  protection,  when  it  has  been  accidentally  destroyed.     The  cuticle  is 
very  speedily  and  completely  replaced,  however ;    the  increased  determination 
of  blood  to  the  Cutis,  which  is  the  consequence  of  the  irritation,  being  favorable 
to  the  accelerated  production  of  Epidermic  cells  from  its  surface.     It  is  proba- 
ble that  pressure  and  friction  may  act  in  the  same  manner ;  for  although  the 
peculiar  thickness  of  the  Epidermis  on  the  palms  and  soles  is  well  marked  even 
in  the  foetus  (in  obvious  preparation  for  the  future  requirements  of  these  parts), 
yet,  when  parts  of  the  surface  on  which  the  Cuticle  was  originally  thin,  are 
habitually  exposed  to  pressure  or  friction,  its  substance  undergoes  a  great  aug- 
mentation.— The  Cuticle  is  completely  exuviated  at  the  close  of  some  Exanthe- 
matous  disease,  especially  Scarlatina ;  and  we  are  probably  to  regard  this  as 
one  of  the  modes  in  which  morbific  matter  is  eliminated  from  the  system 
(§  215).     It  usually  "  desquamates"  in  minute  shreds,  or  peels  off  in  larger 
patches;  but  sometimes  the  entire  cuticle  of  the  hand  or  foot,  even  with  the 
nails  attached,  comes  off  at  once,  like  a  glove  drawn  from  the  hand.     A  new 
Epidermis  is  always,  preformed  beneath  that  which  is  thus  shed;  as  in  the 
normal  exuviation  of  the  lower  animals. 

242.  Mingled  with  the  ordinary  Epidermic  cells,  we  find  some  which  secrete 
Colouring-matter ;  these  are  termed  Pigment-cells.     They  are  not  readily  dis- 
tinguishable in  the  epidermis  of  the  fair  races  of  mankind,  except  in  certain 
parts,  such  as  the  areola  around  the  nipple,  and  in  freckles,  naevi,  &c.     But 
they  are  very  obvious,  on  account  of  their  dark  hue,  in  the  newer  layers  of  the 
Epidermis  of  the  Negro  and  other  colored  races;  and,  like  true  Epidermic  cells, 

1  See  Messrs.  Todd  and  Bowman's  "Physiological  Anatomy,"  p.  862,  Am.  Ed. 

2  See  his  "  Mikroskopische  Anatomic,"  band  ii.  $\  14-22. 


EPIDERMIS. PIGMENT-CELLS. 


249 


Fig.  39. 


they  dry  up,  and  become  flattened  scales,  in  passing  towards  the  surface,  thus 
constantly  remaining  dispersed  through  its  substance,  and  giving  it  a  dark  tint 
when  it  is  separated  and  held  up  to  the  light.  The  color  is  more  apparent  in 
the  cells  of  the  "stratum  Malpighii,"  than  it  is  in  those  of  the  horny  layer; 
and  it  is  particularly  deep  in  the  stratum  of  columnar  cells  that  lies  in  immedi- 
ate contact  with  the  surface  of  the  Cutis  (Fig.  38,  b,  6). — In  all  races  of  men, 
however,  we  find  the  most  remarkable  development  of  Pigment-cells  on  the  inner 
surface  of  the  Choroid  coat  of  the  eye ;  where  they  form  several  layers,  known 
as  the  Piymentum  nigrum.  When  examined  separately,  these  are  found  to  have 
a  polygonal  form,  and  to  have  a  distinct 
nucleus  in  their  interior  (Fig.  39,  A). 
The  black  color  is  given  by  the  accumu- 
lation, within  the  cell,  of  a  number  .of 
flat,  rounded  or  oval  granules,  measuring 
about  1-20, 000th  of  an  inch  in  diameter, 
and  a  quarter  as  much  in  thickness; 
these,  when  separately  viewed,  are  ob- 
served to  be  transparent,  not  black  and 
opaque ;  and  they  exhibit  an  active  move- 
ment when  set  free  from  the  cell,  and 
even  whilst  enclosed  within  it. — The 
Pigment-cells  are  not  always  of  a  simple 
rounded  or  polygonal  form;  they  some- 
times present  remarkable  stellate  pro- 
longations, such  as  those  seen  in  the 
skin  of  the  Frog  (Fig.  86);  and  occa- 
sionally, the  cells  being  more  nearly  ap- 
proximated to  each  other,  these  prolonga- 
tions communicate,  so  as  to  form  a  kind  of 

network. — The  Chemical  nature  of  the  Black  pigment  has  not  yet  been  distinctly 
ascertained ;  it  has  been  shown,  however,  to  have  a  very  close  relation  with  that 
of  the  Cuttle-fish  ink,  or  Sepia,  which  derives  its  color  from  the  pigment-cells 
of  the  ink-bag,  and  to  include  a  larger  proportion  of  carbon  than  most  other 
organic  substances — every  100  parts  containing  58  J  of  that  element. 

243.  It  cannot  be  doubted  that  the  development  of  the  Pigment-cells  of  the 
Skin  is  very  much  influenced  by  exposure  to  light;  and  in  this  respect  there  is 
a  remarkable  correspondence  between  Animals  and  Plants — the  coloration  of 
the  latter,  as  is  well  known,  being  entirely  due  to  that  agent.  Thus,  it  is  a 
matter  of  familiar  experience,  that  the  influence  of  light  upon  the  skin  of  many 
individuals,  causes  it  to  become  spotted  with  brown  freckles  j  these  freckles  being 
aggregations  of  brown  pigment-cells ;  which  either  owe  their  development  to  the 
stimulus  of  light,  or  are  enabled  by  its  agency  to  perform  a  decided  chemical 
transformation,  which  they  could  not  otherwise  effect.  In  like  manner,  the 
swarthy  hue,  which  many  Europeans  acquire  beneath  exposure  to  the  sun  in 
tropical  climates,  is  due  to  a  development  of  dark  pigment-cells ;  and  to  this  we 
usually  find  the  greatest  disposition  in  individuals  or  races  that  are  already  of 
a  somewhat  dark  complexion.  The  deep  blackness  of  the  Negro  skin  seems  de- 
pendent upon  nothing  else  than  a  similar  cause,  operating  through  successive 
generations  (CHAP.  XX.).  It  is  well  known  that  the  new-born  infants  of  the 
negro  and  other  dark  races,  do  not  exhibit  nearly  the  same  depth  of  color  in 
their  skins,  as  that  which  they  present  after  the  lapse  of  a  few  days,  when  light 
has  had  time  to  exert  its  influence  upon  their  surface ;  and  further,  that  in  those 
individuals  who  keep  themselves  during  life  most  secluded  from  its  influence, 
we  observe  the  lightest  hue  of  the  epidermis.  Thus  among  the  intertropical 
nations,  the  families  of  Chiefs,  which  are  not  exposed  to  the  sun  in  the  same 


A.  Choroid  Epithelium,  with  the  cells  filled  with 
pigment,  except  at  a,  where  the  nuclei  are  visible. 
The  irregularity  of  the  pigment-cells  is  seen.     6. 
Grains  of  pigment. 

B.  Pigment-cells  from  the  substance  of  the  Cho- 
roid.   A  detached  nucleus  is  seen.    Magnified  320 
diameters. 


250 


OF  THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 


degree  with  the  common  people,  almost  always  present  a  lighter  hue ;  and  in 
some  of  the  islands  of  the  Polynesian  Archipelago,  bordering  on  the  Equator, 
they  are  not  darker  than  the  inhabitants  of  Southern  Europe. — An  occasional 
development  of  dark  pigment-cells  takes  place  during  pregnancy,  in  some  females 
of  the  fair  races ;  thus  it  is  very  common  to  meet  with  an  extremely  dark  and 
broad  areola  round  the  nipple  of  pregnant  women ;  and  sometimes  large  patches 
of  the  cutaneous  surface,  on  the  lower  part  of  the  body  especially,  become  almost 
as  dark  as  the  skin  of  a  Negro. — On  the  other  hand,  individuals  are  occasionally 
seen  with  an  entire  deficiency  of  pigment-cells,  or  at  least  of  their  proper  secre- 
tion ;  and  this  not  merely  in  the  skin,  but  in  the  eye :  such  persons,  termed 
Albinoes,  are  met  with  alike  among  the  fair,  and  among  the  dark  races.  The 
absence  of  color  usually  shows  itself  also  in  their  hair,  which  is  almost  white. 

244.  The  Nails,  like  Hoof,  Horn,  &c.,  may  be  regarded  as  nothing  more  than 
an  altered  form  of  Epidermis.  When  their  newest  and  softest  portions  are  ex- 
amined, they  are  found  to  consist  of  nucleated  cells  (Fig.  40,  B),  resembling 


Fig.  40. 


Fig.  41. 


Oblique  section  through  the  Matrix  of  the  Nail:   A,  Section  of  the  skin  on  the  end  of  the 

Cutis  of  the  bed  of  the  nail ;  B,  mucous  layer  of  the  finger :  The  cuticle,  and  nail,  n,  detached 

nail;-c,  horny  layer  of  the  same,  or  true  nail-substance;  from  the  cutis  and  matrix,  m. 

a,  papillae  of  the  nail-matrix;  6,  cells  of  the  Malpighian 
gtratum  of  the  nail ;  c,  ridges  of  the  true  nail-substance ; 
d,  deepest  layer  of  perpendicular  cells  of  the  mucous  por- 
tion of  the  nail ;  e,  upper  layer  of  flattened  cells  of  the 
same ;  /,  nuclei  of  the  true  nail-substance. 

those  of  the  newer  layers  of  Epidermis ;  but  in  the  more  superficial  laminae  (c) 
no  distinct  structure  can  be  distinguished  without  the  assistance  of  reagents. 
When,  however,  a  thin  slice  of  the  nail  is  immersed  for  some  little  time  in  a 
dilute  solution  of  caustic  potash  or  soda,  its  tissue  swells  up,  and  its  component 
cells,  though  previously  flattened  and  compacted  together,  reassume  their  sphe- 
roidal form,  and  display  themselves  in  the  most  beautiful  manner  (as  was  first 
pointed  out  by  Donders);  their  nuclei,  however,  are  no  longer  distinguishable 
in  the  most  superficial  layers. — The  Nail  is  produced  from  the  surface  of  the 
Corium  that  lies  beneath  it,  which  is  folded  into  a  groove  at  its  root  (Fig.  41); 
this  surface  is  highly  vascular,  and  is  furnished  with  longitudinal  elevated  ridges 
(Fig.  40,  a,  A),  to  which  bloodvessels  are  copiously  distributed,  and  between 
which  the  soft  inner  layer  of  the  nail  dips  down  (6),  like  the  Malpighian  layer 
of  the  cuticle  between  the  sensory  papillae.  The  increase  of  the  Nail  in  length 
is  effected  by  successive  additions  to  its  root,  causing  the  whole  nail  to  shift 
onwards;  but  as  it  moves,  it  receives  additional  layers  from  the  subjacent  skin, 
which  increase  its  thickness.  According  to  the  observations  of  M.  Beau,  the 


PIGMENT-CELLS. — NAILS.  —  HAIR.  251 

rate  of  growth  in  the  nails  of  the  hands  is  about  2-5ths  of  a  line  per  week ;  whilst 
the  nails  of  th^feet  require  four  weeks  for  the  same  increase.  Thus,  the  length 
of  the  thumb-nail  (including  the  portion  hidden  from  sight)  being  8  lines,  the 
period  occupied  in  its  growth  would  be  twenty  weeks ;  whilst  the  nail  of  the  great 
toe,  in  like  manner,  being  9  lines  in  length,  requires  ninety-six  weeks,  or  nearly 
two  years.  It  has  been  further  remarked  by  M.  Beau,  that  although  the  rate  of 
growth  of  the  nails  is  not  much  affected  by  disease,  the  amount  of  nutriment  they 
receive  is  usually  so  much  diminished,  that  the  portion  of  nail  then  produced  is 
perceptibly  thinner,  and  may  be  distinguished  on  the  surface  as  a  transverse 
groove.  The  breadth  of  this  groove  indicates  the  duration  of  the  disease,  and  its 
depth  marks  the  seriousness  of  the  disturbance  of  the  nutritive  functions ;  whilst 
its  distance  from  the  root  corresponds  with  the  length  of  time  that  has  elapsed 
since  recovery.1  When  a  nail  has  been  removed  by  violence,  or  has  been  thrown 
off  in  consequence  of  the  formation  of  pus  beneath  it,  a  complete  regeneration 
speedily  takes  place,  provided  that  the  matrix  has  received  no  serious  injury. 
The  nail  is  continuous  with  the  true  Epidermis  at  every  part,  except  at  its  free 
projecting  edge,  where  also  the  continuity  is  maintained  in  the  foetus;  so  that  it 
may  be  regarded  as  nothing  else  than  an  extraordinary  development  of  epidermic 
structure,  designed  to  answer  certain  special  purposes  of  a  purely  mechanical 
nature. 

245.  The  Hair,  as  originally  consisting  of  Epidermic  cells,  may  be  properly 
described  here ;  although,  when  fully  formed,  it  departs  widely  (in  Man  at  least) 
from  the  cellular  type.  It  has  been  imagined  until  recently,  that  the  Hair,  in 
common  with  the  other  Epidermic  tissues,  is  a  mere  product  of  secretion ;  its 
material,  which  is  chiefly  horny  matter  of  the  same  composition  with  that  of  the 
Epidermis  and  its  appendages,  being  elaborated  from  the  surface  of  the  pulp  at 
its  base.  It  is  now  known,  however,  to  contain  a  distinctly  organized  structure ; 
and  to  be  formed  by  the  conversion  of  a  cellular  mass  at  its  root  (§  246).  Al- 
though the  Hairs  of  different  animals  vary  considerably  in  the  appearances  they 
present,  we  may  generally  distinguish  in  them  two  elementary  parts ;  a  cortical 
or  investing  substance,  of  a  fibrous  horny  texture ;  and  a  medullary  or  pith- 
like  substance,  occupying  the  interior.  The  relative  proportions  in  which  these 
present  themselves,  are  subject  to  great  variation;  some  hairs  being  almost 
entirely  composed  of  the  medullary  substance,  and  others  almost  as  exclusively 
of  the  cortical.  The  fullest  development  of  both,  however,  is  to  be  found  in 
the  spiny  hairs  of  the  Hedgehog,  and  in  the  quills  of  the  Porcupine,  which  are 
but  hairs  on  a  magnified  scale :  their  cortical  substance  forms  a  dense  horny  tube, 
to  which  the  firmness  of  the  structure  seems  chiefly  due ;  whilst  the  medullary 
substance  is  composed  of  an  aggregation  of  very  large  cells,  which  seem  not  to 
possess  any  fluid  contents  in  the  part  of  the  hair  that  is  completely  formed,  but 
are  occupied  by  air  only.  We  shall  see  that  in  the  Human  hair,  the  predomi- 
nant substance  is  that  which  corresponds  to  the  "  cortical"  of  that  of  the  lower 
animals. — The  diameter  of  the  Hair  is  subject  to  great  variation;  ranging,  on 
the  heads  of  different  individuals  (according  to  the  observations  of  Mr.  Erasmus 
Wilson3),  from  1-1 500th  to  l-140th  of  an  inch;  and  from  l-1500th  to  l-230th, 
even  in  the  same  individual.  The  average,  however,  seems  to  be  about  1 -400th 
of  an  inch,  and  is  rather  greater  in  the  female  than  in  the  male.  As  a  general 
rule,  flaxen  hair  is  the  finest,  and  black  the  coarsest ;  and  the  most  extensive 
range  is  found  in  light  brown  hair.  The  hair  of  the  beard  and  whiskers  is  con- 
siderably coarser  than  that  of  the  head ;  the  former  having  measured  l-200th 
of  an  inch,  when  the  average  of  the  latter  was  l-350th. — When  the  surface  of 
the  shaft  of  the  Hair  is  carefully  examined,  it  is  seen  to  be  covered  with  a  layer 
of  flattened  cells  or  scales,  arranged  in  an  imbricated  manner  (Fig.  43,  c),  their 

1  See  Mr.  Erasmus  Wilson's  "Healthy  Skin,"  3d  edit.  pp.  14-18.      2  Op.  cit.,  p.  59. 


252 


OF    THE   PRIMARY   TISSUES    OF   THE    HUMAN    BODY. 


edges  forming  delicate  lines  upon  the  surface  of  the  hair,  which  are  sometimes 
transverse,  sometimes  oblique,  and  sometimes  apparently  spiral  (Fig.  42,  A). 
Within  this  we  find  a  cylinder  of  fibrous  texture,  which  forms  the  principal  part 
of  the  shaft  of  the  hair ;  the  constituent  fibres  of  this  substance,  which  are  marked 
out  by  delicate  longitudinal  striae  that  may  be  traced  in  vertical  sections  of  the 
hair  (Figs.  42,  B,  43,  6),  may  be  separated  by  crushing  the  hair,  especially  after 
maceration  in  acid ;  and  each  of  them  consists,  as  has  been  shown  by  Prof.  Kol- 
liker,1  of  a  fasciculus  of  flattened  cells  of  a  fusiform  outline. — It  has  been  further 
shown  by  Kblliker,  that  the  color  of  this  portion  of  the  hair  is  due,  not  only  to 
the  presence  of  pigmentary  granules,  either  collected  into  patches,  or  diffused 
through  its  substance ;  but  also  to  the  existence  of  a  multitude  of  lacunulse  con- 
taining air,  which  cause  it  to  appear  dark  by  transmitted  and  white  by  reflected 
light.  Within  the  hollow  cylinder  of  fibrous  substance,  is  found  a  canal  which 
is  occupied  by  the  medullary  portion  of  the  hair  (Fig.  42,  c);  this  consists  of 


Fig.  42. 


Structure  of  Human  Hair:  A,  external  surface  of  the  shaft,  showing  the  transverse  striae  and  jagged  boun- 
dary, caused  by  the  imbrications  of  the  scaly  envelop ;  B,  longitudinal  section  of  the  shaft,  showing  the  fibrous 
character  of  the  cortical  substance,  and  the  arrangement  of  the  pigmentary  matter ;  c,  transverse  section, 
showing  the  distinction  between  the  transparent  envelop,  the  cylinder  of  cortical  substance,  and  the  medul- 
lary centre ;  D,  another  transverse  section  showing  deficiency  of  medullary  substance.  Magnified  310  diameters. 

cells  which  retain  more  or  less  of  the  spheroidal  shape  (Fig.  43,  a);  and  it  gene- 
rally presents  a  darker  hue  than  the  cortical  substance,  partly  through  the  pre- 
sence of  a  larger  quantity  of  pigmentary  matter  in  its  cells,  but  chiefly  through 
the  greater  number  of  air-spaces  that  lie  amongst  them.  The  medullary  sub- 
stance, however,  is  not  unfrequently  wanting  j  being  usually  deficient  in  the  fine 
hairs  scattered  over  the  general  surface  of  the  body,  and  not  being  always  present 
in  the  ordinary  hairs  of  the  head  (D). — The  chemical  composition  of  Hair,  as 
already  stated,  is  precisely  the  same  with  that  of  the  horny  Epidermis  (§  240). 
Its  coloring  matter  seems  related  to  Haematine ;  it  is  bleached  by  Chlorine  j 
and  its  hue  appears  to  be  dependent  in  part  upon  the  presence  of  iron,  which  is 
found  in  larger  proportion  in  dark  than  in  light  hair  (§  87). 

246.  The  real  nature  of  the  different  components  of  the  Hair,  and  their  rela- 
tion to  those  of  the  Epidermis,  is  ascertained  by  examining  them  at  its  base, 
and  tracing  their  origin  and  connections.  The  hair  expands  at  the  base  of  the 
shaft  into  a  bulbous  enlargement;  and  this  is  lodged  within  a  follicle,  formed 
by  a  depression  of  the  Cutis,  and  lined  by  a  continuation  of  the  Epidermis. 
The  exterior  of  this  follicle  (Fig.  43)  is  bounded  by  a  fibrous  membrane,  derived 
from  the  Corium,  whose  fibres  are  longitudinally  arranged  (&);  within  this  is 
another  layer  whose  fibres  lie  transversely  (i);  and  within  this,  again,  is  a  struc- 


Mikroskopische  Anatomic,"  band  ii.  p.  105. 


GROWTH   AND   DEVELOPMENT    OF   HAIR. 


253 


Fig.  43. 


V* 


tureless  membrane,  corresponding  to  the  basement  membrane  of  other  parts. 
The  Epidermic  lining  of  this  follicle,  which  constitutes  what  is  known  as  the 
"  root-sheath,"  is  composed  of  two  principal  layers, 
the  one  (g)  in  contact  with  the  corium  being  the 
continuation  of  the  stratum  Malpighii,  and  the  one 
nearest  the  hair  (e,  /)  bearing  a  like  relation  to  the 
horny  layer.1  At  the  deepest  portion  of  the  follicle, 
according  to  Prof.  Kolliker,  there  arises  a  minute 
papillary  elevation  of  the  Corium  (7),  which  occupies 
the  centre  of  the  hair-bulb ;  and  over  this  we  find  a 
great  accumulation  of  cells  of  spheroidal  form,  which 
are  obviously  continuous  at  m,  with  those  of  the 
outer  root-sheath,  and  which  are  in  every  respect 
analogous  to  those  of  the  Malpighian  layer  of  the 
Epidermis.  The  envelop  of  imbricated  scales  (c,  d\ 
on  the  other  hand,  which  the  bulb  as  well  as  the 
shaft  of  the  hair  presents,  commences  deep  in  the 
follicle  as  a  double  layer  of  nucleated  cells  (»,  o), 
which  forms  a  kind  of  duplicature  of  the  outer  or 
horny  stratum  of  the  Cuticle.  The  fusiform  cells 
of  the  fibrous  portion  of  the  shaft  are  continuous 
with  those  of  the  outer  part  of  the  hair-bulb,  which 
are  seen  to  undergo  elongation  (s),  as  they  are 
pushed  upwards  by  the  development  of  new  cells 
beneath;  and  thus,  as  they  are  at  the  same  time 
narrowed,  the  shaft  comes  to  be  of  less  diameter 
than  the  bulb  at  its  base.  The  cells  of  the  medul- 
lary substance  are  derived  with  less  change  from 
those  of  the  interior  of  the  hair-bulb ;  they  are  at 
first  colorless  (r),  but  gradually  acquire  the  dark 
aspect  which  is  partly  due  to  the  development  of 
pigmentary  matter,  but  still  more  to  the  production 
of  air-spaces  by  their  desiccation. — Thus  we  see  that 
the  whole  tissue  of  the  Hair  is  derived  from  Epider- 
mic cells,  developed  in  peculiar  abundance  from  the 
surface  of  the  papilla  at  the  base  of  the  follicle  which 
is  itself  extremely  vascular;  some  of  these  cells  re- 
taining their  original  form,  whilst  others  are  trans- 
formed into  fibres,  and  others  converted  (like  those 
of  ordinary  Epidermis)  into  flattened  cells.  They  all 
have  the  power,  however,  of  drawing  horny  matter 
into  their  cavities ;  and  resist  the  solvent  power  of 
chemical  reagents,  except  when  these  are  employed 
in  unusual  strength.  The  Hair  is  constantly  under- 
going elongation,  by  the  addition  of  new  substance 
at  its  base ;  and  the  part  which  has  been  once  fully 
formed,  and  which  has  emerged  from  the  follicle, 
usually  undergoes  no  subsequent  alteration.  There 
is  evidence,  however,  that  it  may  be  affected  by 
changes  at  its  base,  the  effect  of  which  is  propagated  along  its  whole  extent : 


Hair-bulb  of  a  well-developed  Hu- 
man Hair,  with  its  follicle :  a,  me- 
dullary substance,  containing  air- 
spaces, with  indistinct  cells;  6. 
fibrous  cortical  substance ;  c,  d,  inner 
and  outer  layers  of  the  scaly  enve- 
lop; e,  /,  inner  and  outer  layers  of 
the  internal  root-sheath ;  g,  external 
root-sheath;  h,  structureless  mem- 
brane; i,  transverse  fibre-stratum; 
k,  longitudinal  fibre-stratum ;  I,  hair- 
papilla  ;  TO,  lowest  cells  of  the  hair- 
bulb,  continuous  with  those  of  the 
external  root-sheath;  n,  perpen- 
dicularly-arranged nucleated  cells. 
which,  near  <?,  become  non-nucle- 
ated, and  are  continuous  with  the 
inner  layer  of  the  scaly  envelop; 
o,  small  perpendicularly  arranged 
cells,  likewise  nucleated,  passing 
into  the  outer  layer  of  the  same; 
p,  lowest  portion  of  the  inner  root- 
sheath;  r,  commencement  of  the 
medullary  substance  in  the  condi- 
tion of  colorless  cells ;  s,  part  where 
the  cells  of  the  bulb  begin  visibly 
to  lengthen  themselves,  to  form  the 
fusiform  cells  of  the  shaft. 


1  According  to  Prof.  Kolliker,  it  is  by  the  laceration  of  a  layer  of  flattened  cells  without 
nuclei,  which  forms  the  outer  stratum  of  the  inner  layer  of  the  root-sheath,  that  the  so- 
called  "fenestrated  membrane"  is  produced,  the  presence  of  which  between  structures 
corresponding  to  the  Malpighian  and  horny  layers  of  the  Epidermis,  has  been  a  subject  of 
much  perplexity  to  Microscopists. 


254 


OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 


Fig.  44. 


thus,  it  is  well  known  that  cases  are  not  unfrequent,  in  which,  under  the  influ- 
ence of  strong  mental  emotion,  the  whole  of  the  hair  has  been  turned  to  gray, 
or  even  to  a  silvery  white,  in  the  course  of  a  single  night ;  a  change  which  can 
scarcely  be  accounted  for  in  any  other  way,  than  %  supposing  that  a  fluid,  capa- 
ble of  chemically  affecting  the  color,  is  secreted  at  the  base  of  the  hair,  and 
transmitted  by  imbibition  through  the  medullary  substance,  to  the  opposite  ex- 
tremity. Another  evidence  of  their  retention  of  a  degree  of  vitality,  is  found  in 
the  fact  of  Hairs  having  a  tendency  to  become  pointed,  after  having  been  cut 
short  off.  In  the  hairs  of  some  animals  (particularly  the  whiskers  of  the  Seal 
and  other  Carnivora)  the  base  is  hollow,  and  contains  a  large  papilla,  or  eleva- 
tion of  the  cutis,  furnished  with  nerves  and  bloodvessels :  this  is  separated,  by  a 
layer  of  basement  membrane,  from  the  proper  tissue  of  the  Hair.  In  such  cases 
there  is  bleeding  from  the  stumps  of  the  hairs,  when  they  are  shaved  off  close 
to  the  skin.  We  have  seen  that  there  is  an  approach  to  this  papillary  structure 
in  man  j  and  it  may  perhaps  be  an  abnormal  development  of  it,  which  occasions 
the  hair  to  bleed  in  the  disease  termed  Plica  Polonica.  The  hair  of  individuals 
affected  with  this,  is  further  disposed  to  split  into  fibres,  often  at  a  considerable 
distance  from  the  roots,  and  to  exude  a  glutinous  substance ;  these  two  causes 
unite  in  occasioning  that  peculiar  matting  of  the  hair,  which  has  given  origin  to 
the  name  of  the  disease. 

247.  The  history  of  the  embryonic  development  of  the  Hair  has  recently 

been  made  the  subject  of  careful  study 
by  Prof.  Kblliker  j  and  the  following  is 
the  substance  of  his  account  of  it.  The 
hair-rudiments  may  be  said  to  be  com- 
posed of  little  processes  of  the  Malpig- 
hian  layer  of  the  epidermis,  which  are 
received  into  corresponding  depressions 
in  the  corium  (Fig.  44,  A,  I,  I);  these 
are  soon  perceived  to  be  inclosed  in  a 
limiting  membrane  (B,  t),  which  sepa- 
rates the  contained  cells  (m,  m)  from 
the  interior  of  the  follicle,  just  as  the 
basement  membrane  of  the  Skin  with 
which  it  is  continuous,  separates  the 
Malpighian  layer  of  the  Epidermis  from 
the  corium.  The  hair-matrix  now 
lengthens  and  swells  out  at  the  bottom, 
so  as  to  assume  a  flask  shape.  Cells 
are  deposited  outside  the  limitary  mem- 
brane, which  are  eventually  converted 
into,  or  give  place  to,  fibres ;  and  thus 
the  dermic  coats  of  the  follicle  are  pro- 
duced.— But  whilst  this  is  going  on  out- 
side, the  cells  within  the  follicle  under- 
go changes.  Those  in  the  middle 
lengthen  out  conformably  with  the  axis 
of  the  follicle,  and  constitute  a  short 
conical  miniature  hair,  faintly  distin- 
guishable by  difference  of  shade  from 
the  surrounding  mass  of  cells,  which 
are  also  slightly  elongated,  but  trans- 
versely with  regard  to  the  follicle  (Fig. 
45,  A.).  The  papilla  (B,  h)  makes  its 
appearance  at  the  swollen  root  of  the 


A.  Development  of  the  Hair-bulbs  in  the  Epider- 
mis of  the  forehead,  in  a  human  foetus  of  sixteen 
weeks,  as  seen  from  the  under  side :  B,  a  single 
hair-matrix  more  enlarged,  as  seen  laterally:  a, 
horny  layer  of  the  epidermis ;  b,  mucous  layer  of 
the  same  ;  i,  structureless  membrane  surrounding 
the  hair-matrix,  prolonging  itself  from  betwixt  the 
mucous  layer  and  the  corium;  m,  rounded  with 
some  elongated  cells,  forming  the  matrix  of  the 
hair. 


DEVELOPMENT   OF   HAIR, 


255 


little  hair ;  and  the  residuary 
cells  contained  within  the  rudi- 
mentary follicle  form  the  root- 
sheath,  the  inner  layer  of  which 
(/),  lying  next  to  the  hair,  is 
soon  distinguished  by  its  trans- 
lucency  from  the  more  opaque 
outer  layer  (c)  that  fills  up  the 
rest  of  the  cavity.  The  young 
hair,  continuing  to  grow,  at  last 
perforates  the  epidermis  (c), 
either  directly,  or  after  first  slant- 
ing up  for  some  way  between  the 
Malpighian  and  the  horny  strata. 
In  the  former  case  it  may,  per- 
haps, be  aided  in  its  progress  by 
the  harder  inner  layer  of  the 
root-sheath,  which  accompanies 
the  hair,  and  makes  way  for  it 
through  the  cuticle.  Prof.  Kol- 
liker  further  thinks  it  not  impro- 
bable that  the  eruption  of  the 
hairs  is  facilitated  by  the  gene- 
ral desquamation  and  shedding 
of  the  superficial  part  of  the  epi- 
dermis, which  occurs  from  time 
to  time  during  foetal  life ;  more 
especially  as  the  period  of  most 
thorough  desquamation  begins 
at  about  the  same  time  as  the  first 
eruption  of  hairs. — A  shedding  of 
the  first-formed  hairs,  or  lanugo, 
is  known  to  take  place  before 
birth ;  but  according  to  Prof. 
Kolliker,  only  to  an  inconsidera- 
ble extent.  On  the  other  hand, 
he  has  observed  that  the  infan- 
tile hairs  are  entirely  shed  and 
renewed  within  a  few  months 
after  birth  ;  those  of  the  general 
surface  first,  and  afterwards  the 
hairs  of  the  eyebrows  and  head, 
which  he  finds  in  process  of 
change  in  infants  about  a  year 
old.  The  new  hairs  are  gene- 
rated in  the  follicles  of  the  old, 
as  previously  seen,  by  Heusinger 
and  Kohlrausch,  in  quadrupeds  ; 
but  Kolliker  describes  the  steps 
of  the  process  somewhat  differ- 
ently from  his  predecessors.  He 
conceives  that  an  increased 
growth  of  cells  takes  place  in  the 
soft  hair-bulb  and  in  the  adjoin- 
ing part  of  the  root-sheath  (Fig. 
46,  A.)  ;  the  growing  mass  pro- 


Fig.  45. 


Development  of  the  Hair  in  the  eyebrows  :  A,  first  'distinct 
separation  of  the  inner  and  outer  portions  of  the  hair-matrix; 
B,  first  formation  of  the  hair,  whose  point  has  not  yet  appeared 
above  the  skin ;  c,  the  hair  soon  after  its  first  emersion : 
a,  horny  layer  of  the  epidermis ;  b,  its  mucous  layer ;  c,  outer 
root-sheath ;  d,  inner  root-sheath ;  e,  hair-bulb ;  /,  hair-shaft ; 
g,  point  of  the  hair ;  h,  hair  papilla ;  i,  structureless  mem- 
brane on  the  exterior  of  the  matrix ;  n,  commencement  of  the 
sebaceous  glands. 

Fig.  46. 


Development  of  second  Eyelashes  in  an  Infant  of  a  year  old  : 
A,  incipient  formation  of  matrix  of  second  hair  ;  B,  incipient 
development  of  the  young  hair,  the  outer  and  inner  portions 
not  yet  distinct ;  c,  the  young  hair,  more  advanced,  and  push- 
ing up  the  old  hair ;  its  proper  substance  distinct  from  the  root- 
sheath  ;  D,  the  young  hair  emerged  from  the  opening,  and  its 
predecessor  about  to  fall  out :  a,  external  root-sheath ;  b,  in- 
ternal root-sheath  of  young  hair ;  c,  cavity  for  the  reception 
of  the  formative  papilla ;  d,  bulb  of  the  old  hair ;  e,  its  shaft ; 
/,  bulb  of  the  young  hair ;  g,  its  shaft ;  h,  its  point ;  i,  i,  se- 
baceous glands ;  k,  k,  sweat-canals ;  I,  passage  of  the  external 
root-sheath  into  the  mucous  layer  of  the  epidermis ;  m,  first 
appearance  of  young  hair. 


256 


OP   THE   PRIMARY   TISSUES    OF    THE    HUMAN   BODY. 


trades  or  lengthens  out  the  lower  end  of  the  hair-follicle  into  a  process,  at  the 
bottom  of  which  is  found  the  generative  papilla  (c)  now,  by  the  interposition 
of  the  new  cell-growth,  withdrawn  from  the  root  of  the  hair.  The  newly-formed 
mass  of  cells  occupying  the  lower  or  prolonged  part  of  the  follicle,  and  rest- 
ing on  the  papilla  (B,  m),  is  gradually  converted  into  a  new  hair  (c,  f,  g,  h)  with 
its  root-sheath  (6),  just  as  happens  in  the  primitive  process  of  formation  in  the 
embryo  j  and  as  the  new  hair  lengthens  and  emerges  from  the  follicle  (D,  </), 
the  old  one  (d,  e),  detached  from  its  matrix,  is  gradually  pushed  nearer  to  the 
opening,  and  at  last  falls  out,  its  root-sheath  having  previously  undergone  a  partial 

absorption.     A  similar  death  of  the  old 

Fig.  47.  hairs,  and  replacement  by  new  ones  gene- 

rated within  the  same  follicles,  seem  to 
take  place  at  intervals  through  the  whole 
of  life  (Fig.  47) ;  and  it  is  obvious,  as 
Mr.  Paget  has  pointed  out,  that  the 
death  of  the  old  •  hair  is  not  the  conse- 
quence of  absorption  at  its  root,  caused 
by  the  development  of  a  new  one  beneath 
it,  but  is  simply  the  termination  of  a 
series  of  degenerative  changes  that  have 
been  for  sometime  in  progress.1  This  is 
one  illustration,  out  of  many  that  might 
be  cited,  of  the  general  fact  of  the 
limited  duration  of  the  individual  parts 
of  the  living  organism  (§  114) ;  the  in- 
tegrity of  which  is  maintained  by  the 
continual  development  of  new  structure, 
in  place  of  that  which  has  become  effete. 
— The  regeneration  of  Hairs  which  have 
been  plucked  out  of  their  follicles 
is  very  complete ;  provided  the  follicles 
themselves,  and  their  papillae,  have  not 
been  injured.  The  cavity  of  the  follicle 
(according  to  the  observations  of  Heu- 
singer)  is  at  first  filled  with  blood,  which 
is  gradually  absorbed  ;  a  dark  spot,  con- 
sisting of  a  cluster  of  newly-formed  epi- 
dermic cells  containing  pigmentary  mat- 
ter, is  seen  upon  the  summit  of  the  pap- 
illa; and  this  gradually  elongates  itself, 
and  undergoes  development  into  the 
several  parts  of  the  new  hair  and  of  its 
sheath,  just  as  in  the  case  of  the  first 
evolution. 


Intended  to  represent  the  changes  undergone 
by  a  hair  towards  the  close  of  its  period  of  exist- 
ence. At  A  its  activity  of  growth  is  diminishing) 
as  shown  by  the  small  quantity  of  pigment  con- 
tained in  the  cells  of  the  pulp,  and  by  the  inter- 
rupted line  of  dark  medullary  substance.  At  B 
provision  is  being  made  for  the  formation  of  a 
new  hair,  by  the  growth  of  a  new  pulp  connected 
with  the  pulp  or  capsule  of  the  old  hair.  c.  A 
hair  at  the  end  of  its  period  of  life,  deprived  of  its 
sheath  and  of  the  mass  of  cells  composing  the  pulp 
of  a  living  hair. 


3.    Of  the  purely  Cellular  Tissues; — Fat  and  Cartilage. 

248.  The  Adipose  tissue,  which  is  only  second  to  the  Areolar  in  the  extent 
of  its  diffusion  through  the  Human  body,  continues  throughout  life,  to  present 
the  primitive  cellular  type  in  its  purest  form  ;  this  tissue,  wherever  it  occurs, 
being  composed  of  an  aggregation  of  cells,  which  never  depart  widely  from  the 
spheroidal  form  (Fig.  48),  the  chief  alteration  in  shape  which  they  undergo 
being  the  flattening  of  their  walls  from  mutual  pressure  (Fig.  49).  Fat-cells 

1  See  Kirkes  and  Paget's  "  Manual  of  Physiology,"  224-6,  Am.  Ed. 


OP   THE   PURELY   CELLULAR   TISSUES.  —  FAT. 


257 


are  dispersed  among  the  interspaces  of  Areolar  tissue,  in  most,  but  not  all,  of 
the  situations  in  which  the  latter  presents  itself;  but  there  are  certain  situa- 


Fig.  48. 


Fig.  49. 


Cells  of  Adipose  Tissue.    Magnified  135  diameters.  Fat  vesicles  assuming  the  polyhedral 

form  from  pressure  against  one  another. 
The  capillary  vessels  are  not  represented. 
From  the  omentum;  magnified  about 
300  diameters. 

tions  in  which  they  are  developed  more  abundantly,  filling  up  interstices,  and 
forming  a  pad  or  tissue  for  the  support  of  movable  parts.  In  all  but  very 
emaciated  individuals,  there  is  a  considerable  amount  of  fat  beneath  the  skin; 
and  it  is  in  great  part  to  its  interposition,  that  the  roundness  and  smoothness  of 
the  surface,  especially  in  the  female,  are  due.  But  fat  is  collected  in  large 
quantities  around  certain  internal  organs,  as  the  kidneys,  where  its  use  is  less 
obvious ;  and  here,  as  well  as  at  the  base  of  the  heart  around  the  origin  of  the 
large  vessels,  in  the  orbit  of  the  eye,  in  the  interior  of  the  bones,  and  within 
the  spinal  canal  between  the  periosteum  and  the  dura  mater,  some  fat  is  always 
left,  however  extreme  may  be  the  general  emaciation. — The  diameter  of  the 
greater  number  of  Fat-cells  is  between  l-300th  and  l-600th  of  an  inch,  but 
larger  and  smaller  sizes  are  frequently  to  be  met  with.  The  nucleus  is  seldom  to 
be  distinguished  in  the  fully-developed  fat-cell ;  but  it  is  probable  that  it  has  not 
ceased  to  exist  there,  but  is  simply  obscured  by  the  oily  cell-contents.  For  not 
only  does  a  nucleus  exist  in  the  fat-cells  of  the  embryo,  which  are  at  first  pel- 
lucid vesicles,  then  become  granular,  and  at  last  acquire  oily  contents ;  and  also 
in  the  rudimentary  fat-cells  closely  resembling  these  in  their  successive  stages, 
which  are  described  by  Prof.  Kolliker  as  existing  in  the  Dartos;  but  also  in 
fat-cells  wholly  deprived  of  their  oily  contents,  which  are  not  unfrequently  met 
with  in  emaciated  or  dropsical  subjects. — When  the  fat-cells  are  aggregated  so 
as  to  form  masses  of  Fat,  they  are  first  collected  into  little  lobular  clusters,  each 
of  which  has  a  delicate  membranous  investment ;  and  these  are  again  united 
into  larger  clusters,  visible  to  the  naked  eye,  whose  further  aggregation  may 
form  masses  of  considerable  size.  The  component  parts  of  these  are  held 
together  by  Areolar  tissue,  and  also  by  the  bloodvessels  which  penetrate  them, 
and  which  ramify  minutely  among  them,  forming  a  capillary  network,  not  only 
upon  the  surface  of  the  smallest  lobules,  but  even  (it  would  appear)  between 
their  contained  fat-cells  (Fig.  50).  In  some  forms  of  Adipose  tissue,  such  as 
the  marrow  of  bones,  it  would  seem  that  very  little  areolar  tissue  exists,  or 
that  it  is  even  entirely  absent ;  and  here  the  capillary  plexus  forms  the  princi- 
pal bond  of  union  between  the  fat-cells.  No  lymphatics  have  been  detected  in 
Adipose  tissue ;  and  it  would  seem  to  be  equally  destitute  of  nerves,  excepting 
of  such  as  are  passing  through  it  on  their  way  to  other  textures ;  thus  account- 
17 


258 


OF   THE   PRIMARY  TISSUES   OF   THE   HUMAN   BODY. 


ing  for  the  known  fact  of  its  being  insensible  except  when  those  trunks  are 
injured.     The  physical  and  chemical  characters  of  the  oleaginous  substances 

Fig.  50. 


Bloodvessels  of  Fat;  1,  minute  flattened  fat-lobule,  in  which  the  vessels  only  are  represented;  3,  the 
terminal  artery ;  4,  the  primitive  vein ;  5,  the  fat  vesicles  of  one  border  of  the  lobule,  separately  represented 
— magnified  100  diameters ;  2,  plan  of  the  arrangement  of  the  capillaries  on  the  exterior  of  the  vesicles — 
more  highly  magnified. 

contained  within  the  fat-cells,  have  already  been  sufficiently  described  (§§  37, 
38).  The  Margarin,  which  is  the  principal  solid  constituent  of  Human  fat,  is 
dissolved  in  the  Olein,  forming  a  thick  oil,  which  remains  fluid  at  the  ordinary 
temperature  of  the  body,  but  congeals  when  cooled  much  below  it.  That  this 
oil  does  not  escape  from  the  fat-cells  during  life,  may  be  attributed  to  the  moist- 
ening of  their  walls  by  the  aqueous  fluid  circulating  through  their  vessels ;  but 
we  find  that  the  contents  of  the  fat-cells  are  taken  back  into  the  general  current 
of  the  circulation  when  the  food  does  not  afford  an  adequate  supply  for  the  pur- 
poses of  respiration ;  and  we  may  probably  explain  this  by  the  alkalinity  of  the 
blood,  which  enables  it  to  exert  a  certain  solvent  power  for  oleaginous  matter, 
and  which  when  the  amount  ordinarily  present  in  the  blood  has  been  exhausted, 
or  nearly  so,  will  be  exercised  upon  the  fat  within  the  cells  of  adipose  tissue, 
and  will  draw  it  into  the  circulating  current.1 

249.  The  relative  quantity  of  Fat  contained  in  the  bodies  of  different  indi- 
viduals, varies  more  than  does  that  of  any  other  tissue.  If  there  be  no  inca- 
pacity for  the  production  of  fat-cells,  the  amount  of  Adipose  tissue  generated 
will  depend  upon  the  quantity  of  their  appropriate  pabulum  that  may  be  supplied; 
and  this  is,  in  fact,  the  surplus  of  the  oleaginous  matter  ingested  in  the  food,  or 
formed  from  its  other  constituents,  after  the  various  demands  made  upon  it  by 
the  wants  of  the  system  in  general  (§§  41,  42)  have  been  supplied.  Hence  the 
formation  of  fat  will  be  promoted  by  the  use  of  oleaginous  food,  by  inactive 
habits  of  life,  and  by  warmth  of  the  surrounding  atmosphere ;  and  it  is  by  atten- 
tion to  these  indications,  that  the  breeders  of  animals  obtain  the  largest  produc- 
tion of  fat  in  the  shortest  time.  There  appears  to  be,  among  some  individuals, 

1  It  has  been  shown  by  Prof.  Matteucci,  that  fatty  matters,  suspended  in  water  in  a 
state  of  fine  division,  on  one  side  of  a  membranous  septum,  will  pass  through  it  endosmoti- 
cally  towards  a  weak  alkaline  solution  on  the  other.  (See  his  "Lectures  on  the  Physical 
Phenomena  of  Living  Beings,"  Dr.  Pereira's  edition,  p.  Ill,  Am.  Ed. 


OF   THE   PURELY   CELLULAR   TISSUES. — CARTILAGE.  259 

an  extraordinary  tendency  to  the  development  of  Adipose  tissue,  which  may 
thus  appropriate  to  itself  the  nutriment  that  is  destined  for  the  supply  of  other 
parts ;  and  this  sometimes  shows  itself  throughout  the  body,  constituting  general 
Obesity  or  Polysarcia,  and  sometimes  in  individual  parts  forming  Lipoma  or 
fatty  tumor.  Although  general  Obesity  is  doubtless  favored  by  the  conditions 
just  referred  to,  yet  it  may  develop  itself  under  circumstances  of  a  very  different 
kind;  namely,  when  the  food  is  neither  rich  nor  abundant,  when  active  exercise 
is  taken,  and  when  the  individual  habitually  exposes  himself  to  a  cool  atmo- 
sphere. And  we  cannot  but  here  recognize  the  same  kind  of  excessive  develop- 
mental power  in  the  Adipose  tissue,  as  shows  itself  locally  in  tumors,  which 
will  even  grow  and  increase  when  the  body  generally  is  in  a  state  of  extreme 
emaciation.  On  the  other  hand,  there  are  individuals  in  whom  there  is 
an  obvious  deficiency  in  the  power  to  generate  this  tissue ;  since  they  never 
become  otherwise  than  lean,  even  under  the  most  favorable  conditions.  Such 
persons,  moreover,  are  usually  very  apt  to  become  "  bilious"  when  they  take  in 
much  oleaginous  matter  with  their  food ;  for  if  the  surplus  be  not  drawn  off  from 
the  blood  in  the  generation  of  Adipose  tissue,  it  is  probably  thrown  for  elimi- 
nation upon  the  liver,  which  organ  is  very  prone  to  be  disordered  by  being  called 
into  excessive  functional  activity. 

250.  Besides  the  support,  combined  with  facility  of  movement,  which  Fat 
affords  to  the  moving  parts  of  the  body,  it  answers  the  important  purpose  of 
assisting  in  the  retention  of  the  animal  temperature,  by  its  non-conducting 
power;  and  the  still  more  important  object,  of  serving  as  a  kind  of  reservoir  of 
combustible  matter  against  the  time  of  need.     Herbivorous  animals,  whose  food 
is  scanty  during  the  winter,  usually  exhibit  a  strong  tendency  to  such  an  accu- 
mulation, during  the  latter  part  of  the  summer,  when  their  food  is  most  rich  and 
abundant ;  and  the  store  thus  laid  up  is  consumed  during  the  winter.     This  is 
particularly  evident  in  the  hybernating  Mammalia,  which  take  little  or  no  food 
during  their  seclusion.     Again,  when  Birds  or  Mammals  are  deprived  of  food, 
the  duration  of  their  lives  is  proportional,  cseteris  paribus,  to  the  amount  of  fat 
they  contain ;  the  immediate  cause  of  death  in  such  cases  being  the  reduction 
of  the  temperature  of  the  body,  which  takes  place  as  soon  as  the  store,  of  com- 
bustible material  is  exhausted  (CHAP.  xni.).     If  there  were  no  such  store  within 
the  system,  we  should  be  dependent  upon  a  constant  supply  of  aliment  for  our 
heat-producing  power ;  and  the  loss  of  even  a  single  meal  might  be  fatal.     This 
condition  is  seen  in  animals  which  have  been  brought  to  the  verge  of  starvation, 
and  which  are  only  at  first  capable  of  digesting  a  small  quantity  of  food ;  for, 
as  Chossat's  experiments  have  shown,  until  they  have  in  some  degree  replaced 
their  fat  by  the  assimilation  of  surplus  nutriment,  they  cannot  sustain  life  except 
by  the  assistance  of  artificial  heat.1 

251.  In   Cartilage,  also,  the  simple  cellular  structure  is  very  obviously  re- 
tained, and  frequently  exists  alone ;  although  in  some  forms  of  this  tissue,  it  is 
united  with  the  fibrous,  or  is  partly  replaced  by  it.     In  all,  however,  the  early 
stage  of  formation  appears  to  be  the  same.     The  structure  originates  in  cells, 
analogous  to  those  of  which  the  rest  of  the  fabric  is  composed ;  but  between 
these  cells,  a  large  quantity  of  hyaline  or  intercellular  substance,  consisting  of 
Chondrin  (§  34),  is  soon  deposited ;  and  the  amount  of  this  substance  usually 
continues  to  increase  simultaneously  with  the  bulk  of  the  cells.     The  original 
cells  are  pushed  farther  and  farther  from  one  another ;  but  new  cells  arise 
between  them,  from  germs  which  are  contained  in  the  hyaline  substance.     The 
first  cells  frequently  produce  two  or  more  young  cells  by  subdivision  (§  104), 
and  this  act  may  be  repeated ;  and  thus  it  is  very  common  to  meet  with  groups 
of  such  cells  or  corpuscles,  consisting  of  two,  three,  or  four  (Fig.  51).     These 

1  See  his  " Recherches  Experimentales  sur  1'Inanition." 


260 


Or   THE  PRIMARY   TISSUES   OF   THE    HUMAN   BODY. 


Fig.  51. 


Section  of  the  branchial  Cartilage  of  Tadpole :  a, 
group  of  four  cells,  separating  from  each  other ;  b,  pair 
of  cells  in  apposition ;  c,  c,  nuclei  of  cartilage  cells ;  d, 
cavity  containing  three  cells. 


groups,  in  the  Articular  cartilages,  which  may  be  considered  as  the  types  of  the 
purely  cellular  form,  usually  lie  perpendicularly  in  the  deeper  part  of  the  car- 
tilage (that  nearest  the  attached  sur- 
face), and  obliquely  or  irregularly  as 
they  approach  the  free  surface,  whilst 
at  and  near  that  surface  they  lie  pa- 
rallel to  it.  The  deeper  groups  are 
composed  of  a  larger  number  of  cells 
than  the  superficial ;  and  in  the  stra- 
tum forming  the  free  surface,  single 
isolated  cells  are  not  unfrequent, 
which  have  been  mistaken  for  epi- 
thelium-cells. The  free  surface  is 
covered  in  the  fcetal  state  by  a  syno- 
vial  membrane;  of  which  the  two 
characteristic  elements  —  basement 
membrane  and  epithelial  cells — may 
be  clearly  recognized.  But  after 
birth,  this  membrane  seems  to  be 
gradually  destroyed  by  pressure  and 
attrition,  and  by  the  retirement  of 
the  superficial  vessels  towards  the  circumference ;  and  appears  in  the  adult  to 
terminate  at  the  margin  of  the  cartilage,  very  little  in  advance  of  the  "  circulus 
articuli  vasculosus." — The  matrix  of  the  cartilage-cells  is  not  as  perfectly  homo- 
geneous as  its  appearance  in  thin  sections  would  seem  to  indicate ;  for  when  a 
shred  of  it  is  detached  from  the  edge  of  a  fractured  cartilage,  it  is  found  to 
tear  in  a  distinctly  filamentous  manner ;  and  the  arrangement  of  the  filaments 
corresponds  with  that  of  the  cells,  being  perpendicular  to  the  attached  surface 
of  the  cartilage,  and  parallel  to  its  free  surface,  where  it  forms  with  the  cells  a 
sort  of  membranous  layer  that  has  been  mistaken  for  synovial  membrane.1  It 
is  interesting  to  observe  that  this  filamentous  arrangement  of  the  intercellular 
substance  becomes  much  more  obvious  in  certain  diseased  states  of  articular 
Cartilages ;  and  that,  concurrently  with  this  change,  its  chemical  composition 
alters  from  chondrin  to  gelatin.3 

252.  The  varieties  in  the  permanent  Cartilages  principally  depend  upon  the 
degree  of  organization  which  subsequently  takes  place  in  the  intercellular  sub- 
stance. If  a  mass  of  Fibres,  analogous  to  those  of  the  fibrous  membranes 
(§  220),  should  originate  in  it,  the  Cartilage  presents  a  more  or  less  fibrous 
aspect  (Fig.  52) ;  in  some  instances  the  Fibrous  structure  is  developed  so  much  at 
the  expense  of  the  cells,  that  the  latter  disappear  altogether,  and  the  whole 
structure  becomes  fibrous.  Sometimes  the  fibres  which  are  developed  are 
rather  analogous  to  those  of  the  Elastic  tissue  (§  221);  these  are  disposed 
around  the  cells,  forming  a  kind  of  network,  in  the  areolse  of  which  they  lie ; 
and  this  kind  of  cartilage  may  be  termed  the  elastic  or  reticular. — The  primi- 
tive cellular  organization  is  for  the  most  part  retained  in  the  ordinary  articular 
cartilages,3  the  cartilaginous  septum  narium,  the  cartilages  of  the  alae  and  point 

1  See  the  excellent  account  of  the  structure  of  Cartilage  by  Prof.  Sharpey,  in  his  Intro- 
duction to  "  Quain's  Elements  of  Anatomy,"  vol.  i.  p.  239,  Am.  Ed. ;  and  Dr.  Leidy's  Memoir 
"  On  the  Intimate  Structure  and  History  of  Articular  Cartilages,"  in  the  "Amer.  Journ. 
of  Med.  Sci.,"  April,  1849. 

2  This  was  first  pointed  out  by  Dr.  Redfern,  in  his  admirable  Treatise  on  "Anormal 
Nutrition  in  the  Human  Articular  Cartilages." 

3  The  articular  cartilages,  at  the  points  where  tendons  are  implanted  into  them,  have 
all  the  characters  of  fibro-cartilage ;  the  fibres  of  the  tendon  being  spread  through  the  in- 
tercellular substance  of  the  cartilage,  for  some  distance,  and  gradually  coalescing  with  it. 


OP   THE   PURELY   CELLULAR   TISSUES.  —  CARTILAGE. 


261 


Fig.  52. 


Section  of  Fibro-Cartilage ;  showing  disposition  of  car- 
tilage cells,  in  areolae  of  fibrous  tissue. 


of  the  nose,  the  semilunar  cartilage  of  the  eyelids,  the  cartilages  of  the  larynx 

(with  the  exception  of  the  epiglottis),  the  Cartilage  of  the  trachea  and  its 

branches,  the  cartilages  of  the  ribs  (in  Man),  and  the  ensiform  cartilage  of  the 

sternum;  and  it  is  seen  also  in  the  tem- 

porary cartilages,  or  those  which  are 

destined  to  undergo  ossification.    The 

fibrous  structure  is  seen  in  all  those 

Cartilages,  which  unite  the  bones  by 

synchondrosis  ;   this   is   the  case  in 

the  vertebral  column  and  pelvis,  the 

cartilages  of  which  are  destitute  of 

corpuscles,  except  in  and  near  their 

centres.      In  the  lower  Yertebrata, 

however,  and  in  the  early  condition 

of  the  higher,  the  fibrous  structure  is 

confined   to   the   exterior,    and   the 

whole   interior   is  occupied   by  the 

ordinary     cartilaginous     corpuscles. 

The  reticular  structure  is  best  seen 

in  the  epiglottis  and  in  the  concha 

auris;    in    the    former    of     these, 

scarcely  any  trace  of  cartilage-cells 

remains  ;  in  the  latter,  the  fibrous  network  disappears  by  degrees  towards  the 

extremity  of  the  concha,  and  the  structure  gradually  passes  into  the  cellular 

form.1 

253.  Cartilage  (at  least  in  its  simplest  form)  is  nourished  without  coming 
into  direct  relation  with  the  Blood  through  the  medium  of  bloodvessels  ;  for 
the  cellular  Cartilages  are  not  penetrated  by  vessels  in  the  healthy  state  ;  and 
although  in  certain  diseased  conditions  they  seem  to  become  distinctly  vascular, 
yet  the  vessels  do  not  extend  into  the  substance  of  the  cartilage  itself,  but  are 
restricted  to  the  new  tissue  in  which  they  are  developed.  Cartilages,  however,  are 
surrounded  by  Bloodvessels  ;  which  form  large  ampullae  or  varicose  dilatations  at 
their  edges  or  on  their  surfaces  (Fig. 

53)  ;  and  from  these  the  Cartilages  Fig.  53. 

derive  tl^eir  nourishment  by  imbibi- 
tion, in  exactly  the  same  manner  as 
the  frond  of  a  sea-weed  (the  structure 
of  which  is  alike  cellular)  draws  into 
itself  the  requisite  fluid  from  the  sur- 
rounding medium.  In  the  thicker 
masses  of  cartilaginous  tissue,  how- 
ever, such  as  the  cartilages  of  the 
ribs,  we  find  canals  excavated  at 
wide  distances  from  each  other  ; 
which  are  lined  by  a  continuation  of 
the  perichondrium  or  investing  mem- 

brane of  the  cartilage,  and  which  thus  allows  its  vessels  to  come  into  nearer  prox- 
imity with  parts  that  would  be  otherwise  too  far  removed  from  them.  The  ves- 
sels, however,  nowhere  pass  from  the  walls  of  these  canals  into  the  substance 
of  the  cartilage.  Similar  vascular  canals  are  found  in  the  temporary  cartilages, 
near  the  points  where  the  ossifying  process  is  taking  place  ;  this  is  well  seen  in 
the  long  bones,  towards  their  extremities.  At  an  early  period  of  fatal  life, 
there  is  no  distinction  between  the  cartilage  that  is  ultimately  to  become  the 


Vessels  between  the  Articular  Cartilage  and  attached 
Synovial  Membrane. 


1  See  Mr.  Toynbee's  Memoir  on  the  "Non-Vascular  Tissues,"  "Phil.  Trans.,"  1841. 


262 


OF   THE   PRIMARY   TISSUES   OF   THE    HUMAN    BODY. 


Osseous  Epiphysis,  and  that  which  is  to  remain  as  Articular  Cartilage  ;  both 
are  alike  cellular ;  and  the  vessels  that  supply  them  with  nutrient  materials 
penetrate  no  further  than  their  surfaces.  At  a  subsequent  period,  however, 
when  the  ossification  of  the  epiphysal  cartilage  is  about  to  commence,  vessels 
are  prolonged  into  it }  and  a  distinct  line  of  demarcation  is  seen  betwixt  the 
vascular  portion,  which  is  to  be  converted  into  Bone,  and  the  non-vascular  part, 
which  is  to  remain  as  Cartilage.  At  this  period,  the  Articular  Cartilage  is 
nourished  by  a  plexus  of  vessels  spread  over  its  free  surface,  beneath  its  syno- 
vial  membrane  (Fig.  54) ;  as  well  as  by  the  vessels,  with  which  it  comes  into 

Fig.  54. 


Vessels  situated  between  the  attached  Synovial  Membrane,  and  the  Articular  Cartilage,  at  the  point  where 
the  ligamentum  teres  is  inserted  in  the  head  of  the  os  femoris  of  the  human  subject,  between  the  third  and 
fourth  months  of  foetal  life ;  a,  the  surface  of  the  articular  cartilage  ;  6,  the  vessels  between  the  articular 
cartilage  and  the  synovia!  membrane ;  c,  the  surface  to  which  the  ligamentum  teres  was  attached ;  d,  the 
Tein ;  e,  the  artery. 

contact  at  its  attached  extremity.  Towards  the  period  of  birth,  however,  the 
sub-synovial  vessels  gradually  recede  from  the  surface  of  the  articular  cartilage ; 
and  at  adult  age  they  have  entirely  left  it,  though  they  still  form  a  band,  the 
"  circulus  articuli  vasculosus,"  which  surrounds  its  margin.  The  Fibrous  car- 
tilages are  somewhat  vascular ;  but  the  vessels  do  not  extend  to  the  cellular 
portions,  where  such  exist. — Neither  lymphatics  nor  nerves  can  be  traced  into 
the  substance  of  Cartilage,  which  may  be  affirmed  with  certainty  to  be  com- 
pletely insensible,  and  this  in  the  state  of  disease  as  well  as  of  health.1  The 
bloodvessels  which  appear  to  pass  into  Cartilages  in  a  state  of  Inflammation,  do 
not  really  penetrate  its  substance,  but  are  limited  to  the  false  membrane  which 
is  developed  de  novo,  and  which  not  only  covers  the  surface  of  the  cartilage,  but 
also  dips  down  into  all  the  inequalities  which  are  produced  by  its  loss  of  sub- 
stance. The  usual  rate  of  its  nutrition  is  probably  very  slow.  Its  functions, 
save  where  it  undergoes  subsequent  transformation,  are  purely  mechanical ;  and 
though  it  is  continually  subjected  to  pressure,  yet  the  extreme  smoothness  of  its 
surfaces,  and  their  constant  lubrication  by  the  synovial  fluid,  diminish  friction 
so  much  as  to  render  this  a  very  slight  cause  of  disintegration.  It  is  not  at  all 
uncommon,  however,  for  Articular  cartilages  to  be  almost  entirely  destroyed 
through  "  anormal  nutrition ;"  and  this  without  any  pain  or  other  symptom  to 
call  attention  to  the  change  in  progress.2  This  process  essentially  consists  in 
the  enlargement  of  the  cartilage-cells,  the  conversion  of  their  nuclei  into  a  mul- 

1  That  the  acute  pain  which  so  commonly  occurs  in  diseases  of  joints  implicating  the 
Articular  Cartilages  is  not  to  be  referred,  as  it  usually  has  been,  to  the  cartilage,  but  to 
the  subjacent  bone,  has  been  in  the  Author's  opinion  most  satisfactorily  proved  by  Dr. 
Redfern,  in  his  Treatise  on  "Anormal  Nutrition  in  the  Human  Articular  Cartilages." 

2  See  Redfern,  Op.  cit. 


STRUCTURE   AND   NUTRITION   OF   THE   CORNEA.  263 

titude  of  corpuscles,  the  fusion  of  the  walls  of  the  cells  with  the  hyaline  sub- 
stance, and  the  rupture  of  the  cells,  whereby  the  contained  corpuscles  are  set 
tree.  At  the  same  time,  the  hyaline  substance  gradually  comes  more  and  more 
fo  present  a  fibrous  appearance ;  and  the  whole  may  thus  degenerate,  until 
scarcely  a  trace  of  the  original  cartilaginous  structure  is  left.  The  progress  of 
disease  is  sometimes  arrested,  however ;  and  a  natural  cure  tends  to  take  place, 
by  the  development  of  a  white  fibrous  membrane  from  the  intercellular  sub- 
stance, with  which  yellow  fibres  are  intermingled  that  are  derived  from  the 
cell-nuclei.  And  it  is  in  this  way  that  the  attempt  is  made  to  bring  together 
the  two  edges  of  an  incised  wound,  or  to  fill  up  loss  of  substance  occasioned  by 
the  actual  removal  of  Cartilaginous  tissue;  for  it  does  not  appear  that  any 
power  exists  in  Cartilage  to  generate  new  tissue  of  its  own  kind  for  such  pur- 
poses. Many  weeks  or  even  months  are  required  by  this  process;  and  hence 
some  observers  have  altogether  denied  that  any  reunion  of  incised  wounds  of 
Cartilage,  or  any  filling  up  of  breaches  of  surface,  ever  takes  place.  (See  Redfern, 
Op.  cit.)  It  is  curious  that  fractures  of  certain  cartilages  (as  those  of  the  ribs) 
are  commonly  repaired  by  osseous  union;  a  fact  which  seems  to  have  reference 
to  the  normal  ossification  of  these  cartilages  among  many  of  the  lower  animals, 
and  to  their  not  unfrequent  conversion  into  bone  in  the  latter  period  of  life  in 
the  Human  subject. 

254.  The  Cornea  of  the  eye  bears  but  a  slight  resemblance  to  Cartilage  in 
regard  to  its  intimate  structure,  though  it  corresponds  with  it  closely  in  the  mode 
of  its  nutrition.  Besides  its  anterior  or  conjunctival  layer,  which  consists  of 
three  or  four  strata  of  epithelium-cells,  and  its  posterior  layer  of  cells  constituting 
the  epithelium  of  the  aqueous  humor,  the  Cornea  proper  has  been  shown  by 
Mr.  Bowman1  to  consist  of  three  layers,  which  he  designates  respectively  as  the 
"  anterior  elastic  lamina/'  the  "lamellated  cornea,"  and  the  "  posterior  elastic 
lamina." — The  lamellated  tissue  which  makes  up  the  principal  substance  of  the 


cornea,  consists  of  superposed  lamellae  (Fig.  55),  which  are  individually  of  no 


3S  up  1 
.55), 


Vertical  section  of  the  Sclerotic  and  Cornea,  showing  the  continuity  of  their  tissue  between  the  dotted  lines, 
a.  Cornea,  b.  Sclerotic.  In  the  cornea,  the  tubular  spaces  are  seen  cut  through,  and  in  the  sclerotic,  the 
irregular  areolse.  Cell-nuclei,  as  at  c,  are  seen  scattered  throughout,  rendered  more  plain  by  acetic  acid. 
Magnified  320  diameters. 

great  extent,  but  are  connected  together  both  horizontally  and  vertically  by 
membranous  prolongations ;  about  sixty  of  these  lamellae  are  estimated  to  inter- 
vene between  any  two  corresponding  spots  on  the  opposite  surfaces  of  the  tissue ; 
and  each  of  them  seems,  when  highly  magnified,  to  present  a  faintly  fibrous  tex- 

1  "  Lectures  on  the  Parts  concerned  in  the  Operations  on  the  Eye,"  pp.  10-22,  and  Todd 
and  Bowman's  "Physiological  Anatomy,"  p.  404,  Am.  Ed. 


264 


OF   THE   PRIMARY   TISSUES   OP   THE   HUMAN   BODY. 


ture.    The  interspaces  left  between  the  superposed  layers  have  the  form  of  tubes, 
arranged  with  tolerable  regularity,  and  constricted  at  intervals  (Fig.  56);  these 

Fig.  56. 


Fig.  57. 

-  Hil 

l® 


Tubes  of  the  Cornea  Proper,  as  shown  in  the  eye  of  the  Ox  by  mercurial  injection.    Slightly  magnified. 

are  more  readily  demonstrated,  however,  in  the  corneae  of  large  quadrupeds  than 
in  that  of  man.  This  lamellated  tissue  is  the  only  part  of  the  cornea,  which  is 
continuous  with  the  sclerotica ;  and  its  fibres  appear  to  be  very  similar,  in  every 
respect  save  their  extreme  transparency,  to  those  of  that  tissue. — The  anterior 
elastic  lamina  is  a  very  thin  stratum  of  homogeneous  membrane,  not  affected  by 
maceration,  boiling,  or  acids,  which  intervenes  between  the  epithelial  layer  and 

the  lamellated  tissue ;  apparently  serving  as  a 
"basement  membrane"  to  the  former;  whilst  it 
is  tied  down  to  the  latter  by  filaments  of  elastic 
tissue,  which  pass  from  its  internal  surface  to 
lose  themselves  among  the  superficial  lamellae. 
This  layer  disappears  at  the  margin  of  the  cor- 
nea, expending  itself  apparently  in  giving  origin 
to  an  increased  number  of  these  filaments,  some 
of  which  pass  into  the  sclerotic  coat. — The  pos- 
terior elastic  lamina  (or  "membrane  of  De- 
mours"  or  "of  Descemet")  resembles  the  ante- 
rior in  the  characters  of  its  texture;  but  its  ad- 
hesion to  the  posterior  surface  of  the  lamellated 
cornea  is  comparatively  slight,  no  filaments 
being  sent  down  from  it  among  the  lamellae . — No 
vessels  can  be  traced  into  the  substance  of  the 
Cornea ;  but  its  margin  (like  that  of  an  articu- 
lar cartilage)  is  surrounded  by  a  vascular  circle, 
which  consists  of  two  sets  of  vessels,  a  super- 
ficial and  a  deep-seated  (Fig.  57).  The  arteries 
of  the  former,  according  to  Mr.  Toynbee,1  are 
derived  from  the  conjunctiva!  membrane,  and 
are  prolonged  for  a  short  distance  upon  the  outer 
layer  of  the  cornea ;  but  they  terminate  in  veins 
at  from  |th  to  £  a  line  from  its  margin.  The  deep- 
seated  vessels  are  derived  from  the  Sclerotic;  and  they  terminate  in  veins  just 
where  its  tissue  becomes  continuous  with  that  of  the  Cornea.  In  diseased  con- 
ditions of  the  Cornea  (as  of  the  articular  cartilages),  both  sets  of  vessels  extend 
themselves  through  it;  the  superficial  not  unfrequently  form  a  dark  band  of 
considerable  breadth  round  its  margin ;  whilst  the  deep-seated  are  prolonged  into 
its  entire  substance.  Notwithstanding  the  absence  of  vessels  in  the  healthy 


Nutrient  Vessels  of  the  Cornea:  A, 
superficial  vessels  belonging  to  the  Con- 
junctival  membrane,  and  continued  over 
the  margin  of  the  Cornea;  B,  vessels  of 
the  Sclerotic,  returning  at  the  margin  of 
the  Cornea. 


Philosophical  Transactions,"  1841. 


STRUCTURE   OF   THE   CRYSTALLINE   LENS. 


265 


Fig.  58. 


lens;  a,  cells  connecting  the 
>,  fibres  of  the  lens, 


Structure  of  the 

body  of  the  lens  fo 

with  slightly  sinuous  edges  (human);  c,  ditto  from  the  Ox,with 
finely  serrated  edges;  d,  ditto  from  the  Cod;  the  teeth  much 


condition  of  this  structure,  incised  wounds  commonly  heal  very  readily,  as  is 
well  seen  after  the  operation  of  extraction  of  Cataract ;  but  the  foregoing  details 
make  evident  the  importance  of  not  carrying  the  incision  further  round  than  is 
necessary ;  since  the  corneal  tissue  should  not  be  cut  off  from  the  supply  of 
nourishment  affdrded  by  the  vessels  in  its  immediate  proximity. 

255.  The  Crystalline  Lens  of  the  Eye  approaches  cartilage,  in  its  structure 
and  mode  of  nutrition,  more  nearly  than  towards  any  other  tissue.  It  may  be 
separated  into  numerous  laminae,  which  are  composed  of  serrated  fibres  that  lock 
into  one  another  by  their  delicately-toothed  margins1  (Fig.  58,  b,  c,  d)',  these 
serrations,  however,  are  much 
less  obvious  on  the  margins  of 
the  fibres  of  the  human  crystal- 
line, than  they  are  in  those  of 
the  lenses  of  fishes.  Each  fibre 
appears  to  be  made  up  of  a  series 
of  cells,  which  coalesce  with  each 
other  at  an  early  period;  and 
these  are  indicated,  even  in  the 
fully-formed  fibres,  by  nuclei 
which  present  themselves  at 
pretty  regular  intervals  in  their 
substance.  A  layer  of  uncon- 
verted cells  (a),  extremely  thin 
and  transparent,  of  unequal  size, 
and  nucleated,  is  always  found 
between  the  surface  of  the  lens 

and   its  capsule,  which  it  brings      coarser.    Magnified  320  diameters. 

into  organic  union.    The  capsule 

is  perfectly  transparent,  homogeneous,  and  very  elastic ;  it  forms  a  perfectly  close 
envelop,  admitting  neither  vessels  nor  nerves  to  the  contained  lens ;  but  it  is 
very  readily  permeable  to  fluids,  as  is  shown  by  the  absorption  from  the  aque- 
ous humor  that  sometimes  takes  place  after  death,  giving  rise  to  the  so-called 
"  liquor  Morgagni,"  the  presence  of  which,  according  to  Mr.  Bowman  (Op.  cit., 
p.  70),  is  not  the  normal  condition. — The  lens  itself  is  at  no  period  of  its  exist- 
ence supplied  with  bloodvessels,  these  being  confined  to  the  capsule.  During 
the  early  part  of  foetal  life,  and  in  inflammatory  conditions  subsequently,  both 
the  anterior  and  posterior  portions  of  the  capsule  are  distinctly  vascular;  the 
latter  being  supplied  from  the  arteria  centralis  retinae,  which  expands  upon  it 
after  having  traversed  the  vitreous  humor,  and  sends  branches  that  pass  round 
the  margin,  to  be  distributed,  with  twigs  from  the  ciliary  processes,  upon  the 
anterior  surface.  The  loops  formed  by  the  latter  gradually  retreat,  during  foetal 
life,  from  the  centre  towards  the  margin,  like  those  of  the  synovial  membranes ; 
and  after  a  time  the  posterior  capsule  also  ceases  to  be  vascular.  The  subsequent 
growth  of  the  crystalline  lens  appears  to  be  very  trifling,  and  appears  to  be  suffi- 
ciently provided  for  by  imbibition  through  its  capsule,  from  the  aqueous  and 
vitreous  humors  which  are  in  contact  with  its  two  surfaces  respectively.  The 
substance  of  which  the  lens  is  composed  seems  to  be  chemically  identical  with 
the  Globulin  of  the  blood-corpuscles  (§  23);  it  contains  about  58  per  cent,  of 
water.  Cases  of  the  regeneration  of  the  crystalline  lens,  after  its  complete  re- 
moval by  extraction,  have  been  put  upon  record ;  but  such  a  reparation  must  be 
extremely  rare,  and  is  probably  limited  to  young  subjects. — The  Vitreous  body 
has  been  commonly  supposed  to  consist  of  a  loose  fibrous  network,  the  areolse  of 
which  are  filled  up  with  fluid,  that  drains  away  slowly  when  the  membrane  is 


See  Sir  David  Brewster,  in  "Philos.  Transact.,"  1833. 


266  OF   THE   PRIMARY   TISSUES   OP   THE   HUMAN   BODY. 

punctured;  but  this  notion  of  its  structure  was  purely  hypothetical,  neither 
fibres  nor  cells  having  been  made  out  by  any  anatomist.  Attempts  have  been 
recently  made  by  Briicke  and  Hanover  to  show  that  this  body  has  a  laminated 
structure ;  but  much  of  the  evidence  adduced  by  them  has  been  shown  by  Mr. 
Bowman1  to  be  fallacious.  Some  such  arrangement  may  be  clearly  made  out, 
however,  in  the  vitreous  body  of  the  Fish's  eye,  and  a  definite  fibrous  texture,  is 
distinguishable  in  that  of  the  Bird ;  so  that  it  is  probable  that  some  approach  to 
it  exists  in  the  vitreous  body  of  Man.  Whatever  may  prove  to  be  its  intimate 
structure,  the  nutrition  of  this  substance  is  certainly  effected  by  the  same  means 
with  that  of  the  cornea  and  crystalline ;  namely,  by  imbibition  from  the  vessels 
distributed  upon  or  near  its  envelop.  The  ciliary  processes  of  the  Choroid 
membrane  are  almost  entirely  composed  of  large  ampullated  vessels,  closely 
resembling  those  of  synovial  membrane  (Fig.  53);  and  the  blood  which  they 
contain  is  probably  one  of  the  chief  sources  of  nutriment  to  the  vitreous  body. 
The  reproduction  of  the  vitreous  body,  an  escape  of  portions  of  which  is  not  at 
all  an  unfrequent  occurrence  during  the  performance  of  operations  upon  the 
eyes,  seems  to  take  place  with  great  rapidity  and  completeness. 

4.    Of  the  Tissues  consolidated  by  Earthy  deposit ; — Bones  and  Teeth. 

256.  Both  the  Fibres  and  Cells  of  the  Animal  tissue  may  be  consolidated  by 
earthy  deposits ;  these  being  chemically  united  with  the  gelatin  of  the  Fibres ; 
or  secreted,  either  alone,  or  in  combination  with  animal  matter,  into  the  cavities 
of  the  Cells.  An  example  of  the  formation  of  a  skeleton  by  the  consolidation 
of  fibresj  is  presented  by  the  shell  and  other  hard  parts  of  the  Echinodermata  f 
the  intimate  structure  of  which,  as  shown  by  the  Microscope,  strongly  reminds 
us  of  Areolar  tissue  that  might  have  undergone  the  calcifying  process.  Again, 
we  have  an  example  of  the  formation  of  a  skeleton  by  the  deposit  of  mineral 
matter  in  the  cavities  of  cells,  in  the  shells  of  Mollusca  ;3  in  many  of  which 
(especially  among  the  "  bivalves")  the  cellular  character  is  permanently  shown, 
a  consistent  membrane  being  left  after  the  carbonate  of  lime  that  consolidated 
the  cells  has  been  dissolved  away  by  an  acid — an  arrangement  precisely  similar 
to  that  which  is  found  in  the  Enamel  of  teeth  (§  275),  though  the  consolidating 
material  is  different.  In  the  skeletons  of  Invertebrated  animals,  which,  with 
few  exceptions  are  dermal  or  tegumentary,  there  is  no  provision  for  any  other 
mode  of  increase  than  that  which  is  effected  by  addition  to  the  surface  or  edges 
of  the  parts  already  formed ;  and  where,  as  in  the  Crustacea,  such  an  addition 
would  not  serve  to  maintain  the  form  of  the  calcified  envelop,  and  to  preserve 
its  adaptation  to  the  muscular  apparatus  which  is  attached  to  its  interior,  it  is 
periodically  thrown  off  and  renewed.  And  in  the  very  few  cases  in  which  ab- 
sorption takes  place  for  the  removal  of  parts  that  have  become  superfluous,  this 
absorption,  like  the  previous  deposition,  is  superficial  only ;  and  is  effected  by 
the  mere  contact  of  an  absorbent  surface,  without  any  penetration  of  vessels 
into  the  substance  to  be  removed.  The  osseous  skeleton  of  the  Vertebrated 
animal,  on  the  other  hand,  is  essentially  formed  by  the  consolidation  of  the 
tissues  immediately  surrounding  the  nervous  centres,  and  of  outgrowths  from 
these  '*  it  is  invested  by  the  muscular  apparatus,  which  gives  motion  to  its  dif- 
ferent parts ;  and  in  order  that  it  may  keep  pace  with  the  progressive  growth  of 
the  organism  in  general,  it  must  be  made  capable  not  merely  of  receiving  addi- 
tions to  its  surface,  but  also  of  having  its  interior  gradually  consolidated  by  new 

1  "Lectures  on  the  Parts  concerned  in  the  Operations  on  the  Eye,"  p.  94,  et  seq. ;  also 
the  "Dubl.  Quart.  Journ.  of  Med.  Sci.,"  Aug.  1848. 

2  See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  3  195,  Am.  Ed. 

3  Op.  cit.,  \  197. 

4  See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  |  320,  b,  et  seq.,  Am.  Ed. 


STRUCTURE   OF   BONE. 


267 


deposits,  and,  in  like  manner,  of  having  the  parts  first  laid  down  removed  by 
subsequent  absorption  from  within  as  well  as  from  without.  Even  when  the 
full  growth  of  the  skeleton  has  been  attained,  nutritive  changes  still  take  place 
in  it ;  and  the  continuance  of  these  seems  to  be  destined,  not  so  much  to  supply 
any  waste  occasioned  by  decomposition — for  this  must  be  very  trifling  in  a 
tissue  of  such  solidity — as  to  keep  the  fabric  in  a  condition  in  which  it  may 
repair  the  injuries  in  its  substance  occasioned  by  accident  or  disease.  The 
degree  of  this  reparative  power  we  shall  find  to  be  proportional  to  the  activity 
of  the  normal  changes  which  are  continually  taking  place  in  the  osseous  tissue  ] 
and  is  thus  much  greater  in  youth  than  in  middle  life,  and  in  the  vigor  of  man- 
hood than  in  old  age. 

257.  When  the  compact  Osseous  substance  of  the  shaft  of  a  long  bone,  or  of 
the  superficial  portions  of  a  flat  bone,  is  examined  with  the  naked  eye,  it  is  seen 
to  possess  a  somewhat  laminated  texture ;  the  external  and  internal  laminae  of 
the  long  bones  being  arranged  concentrically  round  the  medullary  canal  (Fig. 
59,  B,  a),  whilst  in  the  flat  bones  they  are  parallel  to  the  surface.  Towards  the 

Fig.  59. 


A.  Transverse  section  of  ulna,  deprived  of  its  earth  by  an  acid.    The  openings  of  the  Havorsian  canals  seen. 
Natural  size.    A  small  portion  is  shaded,  to  indicate  the  part  magnified  in  Fig.  B. 

B.  Part  of  the  section  A,  magnified  20  diameters.    The  lines  indicating  the  concentric  lamelke  are  seen,  and 
among  them  the  corpuscles  or  lacunae  appear  as  little  dark  specks. 

extremities  of  the  long  bones,  and  between  the  external  plates  of  the  flat  bones, 
are  a  number  of  cancelli,  or  small  hollows  bounded  by  very  thin  plates  of  bone ; 
these  communicate  with  the  medullary  canal  where  it  exists ;  having,  like  it,  an 
extremely  vascular  lining  membrane;  and  their  cavities  being  filled  with  a 
peculiar  adipose  matter.  Even  the  hard  substance  of  the  bone  is  traversed  by 
canals,  on  which  the  name  of  "Haversian"  has  been  bestowed,  after  their  dis- 
coverer ;  these  canals  run  for  the  most  part  in  the  direction  of  the  laminse ;  but 


268 


OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 


Fig.  60. 


they  have  many  transverse  communications,  both  with  each  other  and  with  the 
medullary  cavity,  so  that  they  form  a  complete  net- 
work (Fig.  60),  which  is  lined  by  a  continuation  of 
the  membrane  of  the  latter.  Their  diameter  varies 
from  l-200th  to  l-2000th  of  an  inch ;  the  average 
being  probably  about  l-500th.  The  smaller  ones 
contain  only  a  single  capillary  vessel ;  but  several 
such  vessels  seem  to  exist  in  the  larger  ones,  together 
with  adipose  matter.  When  a  thin  transverse  sec- 
tion of  a  long  bone  is  made,  and  is  highly  magnified, 
it  is  seen  that  the  bony  matter  of  the  greater  part  of 
its  thickness  is  arranged  in  concentric  circles  round 
the  orifices  of  the  canals  (Fig.  61) ;  these  circles  are 
marked  by  a  series  of  stellated  points ;  and  when  the 
latter  are  magnified  still  more  highly  (Fig.  62),  they 
are  seen  to  be  cavities  or  lacunas  of  a  peculiar  form, 
which  seems  characteristic  of  Bone.  They  are  usu- 
ally oval  or  lenticular  in  form ;  and  are  so  placed, 
that  one  of  their  largest  surfaces  is  turned  from,  and 
the  other  toivctrds,  the  Haversian  canal.  Their  long 
diameter  in  Man  is  commonly  from  l-2400th  to 
l-1600th  of  an  inch ;  their  short  diameter  is  about 
one-third,  and  their  thickness  about  one-sixth,  of 
their  length. — It  has  been  shown  by  Mr.  J.  Quekett,1 
that  there  are  differences  in  the  form  and  size  of  the 
lacunae,  in  the  several  classes  of  Vertebrated  ani- 
mals, sufficiently  characteristic  to  allow  of  the  as- 
signment of  minute  fragments  of  bone,  with  the 

aid  of  the  microscope,  to  their  proper  group. 

Fig.  61. 


Haversian  canals,  seen  on  a  lon- 
gitudinal section  of  the  compact 
tissue  of  the  shaft  of  one  of  the 
long  bones ;  1,  arterial  canal ;  2, 
venous  canal ;  3,  dilatation  of  an- 
other venous  canal. 


Portion  of  transverse  Section  of  Human  Clavicle,  showing  the  orifices  of  the  Haversian  canals,  and  the  concen. 
trie  arrangement  of  the  laminae  of  bony  matter,  and  of  the  lacunae  around  them.    Magnified  85  diameters. 

1  "  Transactions  of  the  Microscopical  Society,"  vol.  ii.     See  also  "Princ.  of  Pliys.,  Gen. 
and  Comp.,"  \  202,  Am.  Ed. 


STRUCTURE    OF   BONE. 


269 


258.  From  all  parts  of  the  lacunae,  but  especially  from  their  two  largest  sur- 
faces, proceed  a  large  number  of  minute  canaliculi,  which  traverse  the  substance 
of  the  bone,  and  communicate  irregularly  with  one  another  (Fig.  62).     Their 
direction,  however,  possesses  a  certain  degree  of  determinateness ;  for  those 
passing  off  from  the  inner  surface  converge  towards  the  Haversian  canal  j  whilst 
those  passing  off  from  the  outer  surface  diverge  in  the  contrary  direction,  so  as 
to  meet  and  inosculate  with  those  proceeding  inwards  from  the  lacunae  of  the 
next  annulus.     In  this  manner,  a  communication  is  kept  up  between  the  Haver- 
sian canal  and  the  most  external  of  its  concentric  lamellae  of  bone.     It  is  not 
to  be  imagined,  however,  that  Hood  can  be  conveyed  by  these  canaliculi,  their 
size  being  far  too  small ;  for  their  diameter,  at  their  largest  part,  is  estimated  at 
from  144,000th  to  l-20,000th  of  an  inch,  whilst  that  of  the  smaller  branches 
is  from  l-40,000th  to  l-60,000th  of 

an  inch ;  so  that  the  blood-corpuscles  Fig-  62. 

could  not  possibly  enter  them.  But 
it  may  be  surmised  that  they  draw 
fluid  from  the  nearest  bloodvessels, 
and  thus  keep  up  a  sort  of  circulation 
through  the  osseous  substance,  which 
may  contribute  to  its  growth,  and 
may  keep  it  in  a  state  fit  for  repair- 
ing itself,  when  injured  by  disease 
or  violence.1 

259.  Although  a  large  quantity 
of  blood  is  sent  to  Bone,  the  vessels 
do  not  penetrate  its  minute  parts ; 
being    confined    to    the   medullary 
cavity,  and  to  the  Haversian  canals 
and  the  cancelli,  which  are  prolon- 
gations of  it.     The  substance  of  the 

Bone,  therefore,  is  really  as  non-  Portion  of  a  transverse  section  of  the  Human  Clavicle, 
Vascular  as  that  Of  Cartilage  ,  the  more  highly  magnified,  to  show  the  lacunae  and  canaliculi. 

only   difference    being,    that    it   is 

channelled  out  by  more  numerous  inflections  of  the  external  surface,  and  that 
the  vessels  are  thus  brought  into  nearer  proximity  with  its  several  parts.  The 
delicate  osseous  lamellae,  which  form  the  walls  of  the  cancelli,  and  of  the  large 
"  cells"  excavated  in  some  of  the  cranial  bones,  have  a  structure  precisely  analo- 
gous to  that  of  the  cylindrical  laminae  surrounding  the  Haversian  canals  of  the 
long  bones ;  and  derive  their  nourishment  from  the  vascular  membrane  cover- 
ing their  surface,  through  the  medium  of  a  similar  set  of  lacunse  and  canaliculi. 
They  do  not  themselves  contain  Haversian  canals  or  cancelli ;  because  no  part 
of  their  substance  is  far  removed  from  a  vascular  membrane. — The  cylindrical 
rods,  that  make  up  the  hollow  shaft  of  a  long  bone,  are  connected  together  by 
solid  osseous  substance,  which  is  composed  of  lamellse  running  parallel  to  the 

1  The  lacunae  and  canaliculi  of  Bone  were  formerly  supposed,  on  account  of  the  dark 
aspect  they  exhibit  under  the  Microscope,  when  viewed  as  transparent  objects,  and  their 
white  appearance  when  viewed  by  reflected  light,  to  be  filled  with  opaque  matter ;  but  the 
former  is  common  to  all  cavities  excavated  in  a  highly-refracting  substance  (being  shown 
by  a  bubble  of  air  in  water),  and  ceases  when  a  very  thin  section  of  Bone  is  examined, 
especially  if  it  have  been  placed  in  Canada  balsam ;  and  the  latter  seems  due  to  some 
peculiar  state  of  the  earthy  deposit  immediately  surrounding  the  cavities,  as  it  may  be 
removed  by  the  agency  of  an  acid.  In  the  bones  of  Mummies,  these  cavities  are  found  to 
be  filled  with  a  waxen  material ;  whilst  in  those  which  have  lain  in  bogs,  they  are  rendered 
peculiarly  distinct  by  the  infiltration  of  some  of  the  surrounding  black  matter ;  and  it  is 
not  difficult  to  make  them  imbibe  liquids,  even  whilst  they  are  under  observation  beneath 
the  Microscope. 


270 


OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 


Fig.  63. 


external  surface  of  the  bone ;  and  these  seem  to  derive  their  nutriment  either 
from  the  periosteum,  or  from  the  membrane  lining  the  central  medullary  cavity; 
according  as  they  are  nearest  to  one  or  to  the  other.  The  membranous  lining  of 
the  canals  of  Bone  appears  to  be  supplied  with  lymphatics,  and  also  with  nerves ; 
but  with  both  in  a  very  limited  amount.  The  periosteum  seems  to  be  scarcely 
(if  at  all)  sensible  in  the  state  of  health,  although  painfully  so  when  inflamed; 
and  the  same  may  be  said  of  the  membrane  lining  the  Haversian  canals  and 
cancelli.  The  membrane  lining  the  central  medullary  cavity,  however,  is  more 
sensitive ;  since  unequivocal  signs  of  pain  are  manifested  by  an  animal,  when, 
a  bone  having  been  sawn  across,  a  probe  is  passed  up  the  cavity,  or  an  acrid 
fluid  is  injected  into  it. 

260.  When  a  Bone  is  subjected  to  the  action  of  dilute  nitric  or  muriatic  acid, 
which  dissolves  away  the  calcareous  matter,  a  substance  is  left  which  possesses  con- 
siderable tenacity,  but  which  is  at  the  same  time  very  flexible.     This  is  commonly 
termed  Cartilage ;  but  the  name  is  inappropriate,  since  it  has  neither  the  structure 
nor  the  chemical  composition  of  that  tissue.     The  animal  basis  of  Bone  is  not  clion- 
drin,  the  characteristic  principle  of  Cartilage  (§  34);  but  glutiny  the  organic  compo- 
nent of  the  White  Fibrous  tissue  (§  33).     When  "examined  microscopically,  it 
does  not  exhibit  any  cartilage-cells,  but  presents  the  laminated  texture  of  the 
original  bone ;  and  the  lacunae  are  still  apparent,  although  their  canaliculi  cannot 

be  readily  traced.  When  a  very  thin  lamella  is  peeled 
off  the  surface  of  the  bone,  it  is  found  to  have  a  dis- 
tinctly fibrous  structure ;  being  composed,  as  was  first 
pointed  out  by  Dr.  Sharpey,1  of  fibres  in  all  essential 
respects  resembling  those  of  the  White  Fibrous  tissue, 
which  decussate  one  another  obliquely,  so  as  to  form 
an  exceedingly  fine  network,  apparently  adhering  to 
each  other  at  the  points  of  intersection  (Fig.  63).  The 
minute  apertures  between  the  reticulated  fibres  seein  to 
give  passage  to  the  canaliculi. — If  very  thin  sections 
of  unaltered  Bone,  however,  be  examined  with  a  high 
power,  the  solid  portion  lying  between  the  lacunae  and 
the  canaliculi  presents  somewhat  of  a  granular  appear- 
ance ;  the  granules,  as  stated  by  Mr.  Tomes,2  are  often 
distinctly  visible  without  any  artificial  preparation,  in 
the  substance  of  the  delicate  spicules  of  the  cancelli, 
when  they  are  viewed  with  a  high  power ;  and  are  made 
very  evident  by  a  prolonged  boiling  in  a  Papin's  di- 
gester. They  vary  in  diameter  from  l-6000th  to 
l-14,000th  of  an  inch ;  their  shape  is  oval  or  oblong, 
often  angular;  and  they  cohere  firmly  together,  possi- 
bly by  the  medium  of  some  different  material.  Their 
own  substance  appears  to  be  perfectly  homogeneous; 
but  it  is  made  up  of  several  components,  as  is  demonstrated  by  Chemical  analysis. 
It  appears  certain,  however,  that  the  mineral  matters  must  be  intimately  united 
with  the  organized  tissue,  and  not  merely  deposited  in  its  interstices ;  since  no 
distinction  can  be  seen  between  them,  even  under  the  highest  magnifying 
powers. 

261.  When  the  Calcareous  matter  of  Bone  has  been  removed  by  the  action  of 
an  acid,  the  Animal  substance  which  remains  is  almost  entirely  dissolved  by  a 
short  boiling  in  water ;  yielding  to  it  a  large  quantity  of  Glutin.     This,  indeed, 

1  See  his  excellent  account  of  the  structure  and  development  of  Bone,  in  his  Introduc- 
tion to  "  Quain's  Elements  of  Anatomy,"  p.  80,  vol.  i.,  Am.  Ed. 

2  Todd  and  Bowman's  "Physiological  Anatomy,"  p.  112,  Am.  Ed.,  and  "Cyclopedia  of 
Anatomy  and  Physiology,"  art.  "Osseous  Tissue." 


Thin  layer  peeled  off  a  soft- 
ened bone,  as  it  appears  under 
a  magnifying  power  of  400.  The 
figure,  which  is  intended  to  re- 
present the  reticular  structure 
of  a  lamella,  gives  a  better  idea 
of  the  object  when  held  rather 
farther  off  than  usual  from  the 
eye. 


COMPOSITION   OF   BONE. 


271 


may  be  obtained,  by  long  boiling  under  pressure,  from  previously-unaltered  Bone ; 
and  the  calcareous  matter  is  then  left  almost  pure.  The  Lime  of  bones  is,  for 
the  most  part,  in  the  state  of  Phosphate  (§  76) ;  but  a  certain  proportion  of 
Carbonate  is  always  present.  The  following  are  the  results  of  some  of  the  most 
recent  and  careful  analyses  of  Human  Bone,  by  Marchand  and  Lehmann  :  those 
of  the  former  were  made  on  the  compact  substance  of  the  femur  of  a  man  aged 
30 ;  and  those  of  the  latter  on  the  long  bones  of  the  arm  and  leg  of  a  man  of 
40  years  of  age. 

Organic  matter. 

Cartilage  insoluble  in  hydrochloric  acid 

Cartilage  soluble  in  hydrochloric  acid 

Vessels      .         .         .         .         .    ".  ,  . 
Inorganic  matter. 

Phosphate  of  lime 

Fluoride  of  calcium 

Carbonate  of  lime 

Phosphate  of  magnes  a 

Soda . 

Chloride  of  sodium 

Oxides  of  iron  and  manganese,  and  loss 


MARCHAND. 

LEHMANN. 

27.23     ] 

5.02 

-     32.56 

1.01     . 

52.26     - 
1.00 

[     54.61 

10.21 

9.41 

1.05 

1.07 

.92 

1.11 

'       0.25 

0.38 

1.05 

.86 

100.00 


100.00 


According  to  Dr.  Stark,1  the  relative  proportions  of  cartilaginous  and  earthy 
matter,  in  the  bones  of  different  animals,  in  the  bones  of  the  same  animals  at 
different  ages,  and  in  the  different  bones  of  the  same  body,  never  depart  widely 
from  the  preceding  standard ;  the  amount  of  earthy  matter  being  always  found 
to  be  just  double  that  of  the  cartilaginous  basis,  when  the  bones  have  been  care- 
fully freed  from  oily  matter,  and  completely  dried,  previously  to  the  analysis. 
The  hardness  of  bone,  he  maintains,  does  not  at  all  depend  upon  the  presence  of 
an  unusually  large  proportion  of  earthy  matter ;  nor  does  their  increased  flexi- 
bility and  transparency  indicate  a  deficiency  of  the  mineral  ingredients  :  for  the 
transparent  readily-cut  bones  of  Fish  contain  the  same  amount  of  earthy  matter, 
in  proportion  to  their  gelatinous  basis,  as  do  the  dense  ivory-like  leg-bones  of  the 
Deer  or  Sheep.  The  same  holds  good  of  the  bones  even  of  the  so-called  Carti- 
laginous Fish.  The  difference  appears  to  depend  upon  the  molecular  arrangement 
of  the  ultimate  particles ;  and  especially,  it  seems  likely,  upon  the  relative  amount 
of  water  which  the  bones  contain. 

.  262.  Probably  the  most  exact  and  comprehensive  analyses  yet  made  of  Bone, 
are  those  of  Von  Bibra  f  whose  laborious  investigations  may  be  said  to  have 
almost  exhausted  the  subject.  The  following  table  shows  the  relative  propor- 
tions of  the  principal  ingredients,  in  some  of  the  principal  bones  of  a  woman 
aged  25  years. 


Organic  matter. 
Cartilage 
Fat  . 


Inorganic  matter. 

Phosphate  of  lime  with  ~| 
a  little  fluoride  of  cal-  >- 
cium  J 

Carbonate  of  lime 

Phosphate  of  magnesia 

Soluble  salts 


Femur. 

29.54 
1.82 


Occipital 
bone. 

29.87 
1.40 


Scapula.        Rib. 


32.90 
1.73 


33.06 
2.37 


Os  inno-    Vertebra.  Sternum, 
minatum. 

38.26      43.44      46.57 
1.77        2.31        2.00 


57.42      57.66      54.75      52.91      49.72      44.28      42.63 


8.92 
1.70 
0.60 


8.75 
1.69 
0.63 


8.58 
1.53 
0.51 


8.66 
1.40 
0.60 


8.08 
1.57 
0.60 


8.00 
1.44 
0.53 


7.19 
1.11 
0.50 


100.00    100.00    100.00    100.00     100.00    100.00    100.00 


1  "Edinb.  Med.  and  Surg.  Journal,"  April,  1845. 

2  "Chemische  Untersuchungen  iiber  die  Knochen  und  Ziihne  des  Menschen,  und  der 
Wirbelthiere." 


272 


OF  THE   PRIMARY   TISSUES    OF   THE   HUMAN   BODY. 


The  analyses  of  the  long  bones  of  the  arm  and  leg  correspond  closely  with 
that  of  the  femur ;  but  we  observe  that  the  proportions  of  ingredients  in  the 
more  spongy  bones  are  widely  different.  It  is  difficult,  however,  to  say  how  far 
this  variation  is  due  to  a  difference  in  the  proportions  of  gelatin  and  earthy 
matter,  in  the  actual  osseous  substance ;  or  how  far  it  may  be  accounted  for  by 
the  presence  of  an  increased  proportion  of  membrane,  forming  the  lining  of  the 
cancelli. — The  same  uncertainty  must  attend  the  explanation  of  the  differences 
that  present  themselves  at  different  ages;  as  shown  in  the  following  table, 
which  gives  a  series  of  comparative  analyses  of  the  long  bones,  generally  the 
femur. 


Organic  matter. 

Cartilage      .        ,»' 

Fat      ... 
Inorganic  matter. 

Phosphate  of  lime  with  ~\ 
a  little  fluoride  of  cal-  i- 
cium  .  .  *;<ij 

Carbonate  of  lime 

Phosphate  of  magnesia 

Soluble  salts 


Foetus 
6  months. 

40.38 
a  trace 


53.46 

3.06 
2.10 
1:00 


Foetus 
7  months. 

34.18 
0.63 


57.63 

5.86 
1.10 
0.60 


Child 
2  months. 

33.86 
0.82 


57.54 

6.02 
1.03 
0.73 


Child 
5  years. 

31.28 
0.92 


59.96 

5.91 
1.24 

0.69 


Man 

25  years. 

29.70 
1.33 


59.63 

7.33 
1.32 
0.69 


Woman 
62  years. 

28.03 
2.15 


63.17 

4.46 
1.29 
0.90 


100.00        100.00        100.00        100.00        100.00        100.00 


From  this  it  will  be  seen,  that  there  is  a  gradual  diminution  in  the  proportion 
of  animal  matter,  through  life  ;  and  a  corresponding  increase  in  the  proportion 
of  the  earthy  components.  But  this  is  not  nearly  so  great  as  is  usually  sup- 
posed; and  the  greater  solidity  of  the  bones  of  old  persons  is  doubtless  owing 
chiefly  to  the  fact,  that  their  cavities  are  progressively  contracted,  by  the  addi- 
tion of  new  bony  matter  (§  265). 

263.  The  first  Development  of  Bone  may  take  place  in  the  substance,  either 
of  Membrane,  or  of  Cartilage.1  The  tabular  bones  forming  the  roof  of  the 
cranium  afford  a  good  example  of  the  first,  or  intra-membranous  form  of  Ossifi- 
cation; for  their  place  is  but  in  part  preoccupied  by  cartilage,  only  a  membrane 
being  elsewhere  interposed  between  the  dura  mater  and  the  integuments  (Fig. 
64).  This  membrane  is  chiefly  composed  of  fibrous  fasciculi,  corresponding  with 
those  of  the  white  fibrous  tissues  ;  but  amongst  these  are  seen  numerous  cells, 
some  about  the  size  of  blood-disks,  but  others  two  or  three  times  larger,  contain- 
ing granular  matter  ;  and  a  soft  amorphous  or  faintly-granular  matter  is  also 
found  interposed  amidst  the  fibres  and  cells.  In  certain  parts,  the  fibres  pre- 
dominate; and  in  others,  the  cells.  The  process  of  ossification  here  seems  at 
first  to  consist  in  the  consolidation  of  the  fibres  by  earthy  matter  ;  for  the  first 
bony  deposit  consists  of  an  irregular  reticulation,  very  loose  and  open  towards 
its  edges,  where  it  frequently  presents  itself  in  the  form  of  distinct  spicula,  which 
are  continuous  with  fasciculi  of  fibres  in  the  surrounding  membrane  (Fig.  65). 
The  limits  of  the  calcifying  deposit  may  be  traced  by  the  opaque  and  granular 
character  of  the  parts  affected  by  it;  and  it  gradually  extends  itself,  involving 
more  and  more  of  the  surrounding  membrane,  until  the  foundation  is  laid  for 
the  entire  bone.  Everywhere,  the  part  most  recently  formed  consists  of  a  very 
open  reticulation  of  fibro-calcareous  spicula;  whilst  the  older  part  is  rendered 
harder  and  more  compact,  by  the  increase  in  the  number  of  these  spicula,  and 

1  In  recent  times,  the  development  of  Bone  from  Cartilage  has  received  almost  exclusive 
attention;  but  the  older  opinion,  that  Bone  is  often  developed  in  Membrane,  has  been 
lately  brought  again  into  notice  by  Dr.  Sharpey  (Op.  cit.,  vol.  i.  p.  83,  et  seq.,  Am.  Ed.), 
who  has  demonstrated  its  truth  by  Microscopic  research.  The  statements  in  the  text, 
upon  this  part  of  the  subject,  are  derived  from  Dr.  Sharpey's  observations,  which  the 
Author  has  himself  confirmed. 


DEVELOPMENT   OF   BONE. 


273 


perhaps  also  by  the  calcification  of  the  intervening  cells.     As  the  process  ad- 
vances, and  the  plate  of  bone  thickens,  a  series  of  grooves  or  furrows,  radiating 


Fig.  64. 


Fig.  65. 


Process  of  ossification  in  parietal  bone  of  an  embryo 
sheep  of  2^  inches  in  length.  The  small  upper  figure  re- 
presents the  bone  of  the  natural  size,  the  larger  figure  is 
magnified  about  12  diameters.  The  curved  line,  a,  6, 
marks  the  height  to  which  the  subjacent  cartilaginous 
lamella  extended.  A  few  insulated  particles  of  bone  are 
seen  near  the  circumference,  an  appearance  which  is 
quite  common  at  this  stage. 


The  growing  ends  of  two  bony  spicula  from 
the  frontal  bone  of  an  embryo  dog,  highly  mag- 
nified. The  surrounding  membrane  has  been 
removed,  and  most  of  the  corpuscles  are  washed 
away,  to  show  more  evidently  the  transparent 
soft  fibres  prolonged  from  the  bone,  with  the 
dark  earthy  deposit  advancing  into  them. 


from  the  ossifying  centre,  are  found  upon  its  surface;  and  these,  by  a  further 
increase  in  thickness,  occasioned  by  a  deposit  of  ossific  matter  all  around  them, 
are  gradually  converted  into  closed  canals  (the  Haversian),  which  contain  blood- 
vessels, supported  by  processes  of  the  investing  membrane.  Further  deposits 
subsequently  take  place  in  the  interior  of  these  canals ;  which  thus  gradually 
produce  a  diminution  of  their  caliber,  and  a  consolidation  of  the  bone ;  and  in 
this  manner  its  two  surfaces  acquire  their  peculiar  density,  whilst  the  interven- 
ing layer,  or  "diploe,"  retains  a  character  more  resembling  that  of  the  original 
osseous  reticulation. — The  mode  in  which  the  peculiar  lacunae  and  canaliculi  are 
formed,  in  the  concentric  layers  around  the  Haversian  canals,  probably  corre- 
sponds with  that  in  which  they  are  generated  in  the  intra-cartilaginous  form  of 
ossification,  to  which  we  shall  next  proceed. 

264.  In  a  very  large  proportion  of  the  skeleton,  the  appearance  of  the  Bones 
is  preceded  by  that  of  Cartilages;  which  serve  (so  to  speak)  as  the  moulds  for 
their  formation,  and  which  also  seem  destined  to  afford  a  certain  degree  of  sup- 
port to  the  surrounding  soft  parts,  until  the  production  of  bone  has  taken  place. 
The  temporary  Cartilages  differ  in  no  essential  particular  of  structure  or  compo- 
18 


274 


OP   THE   PRIMARY   TISSUES    OF   THE    HUMAN   BODY. 


sition,  from  the  permanent.  They  present  the  same  irregular  scattering  of  cells 
through  a  homogeneous  intercellular  substance;  and  there  is  the  same  absence 
of  any  vascularity  in  the  cartilaginous  tissue  itself.  In  all  considerable  masses, 
however,  we  find  a  coarse  network  of  canals,  lined  by  an  extension  of  the  peri- 
chondrium  or  investing  membrane ;  and  these  canals,  which  may  be  regarded  as 


_jgL_j.^     ,iC3B      _^*-v.Vf%-     V   TOM    .or>\flft  ~  fftAV^-.-v^    r^  Vxjy.    ' V  v-^*?  -\*y_*  _v^yV 

Transverse  section  of  Cartilage  close  to  the  plane  of  Ossification. 
Fig.  67.  Fig.  68. 


Vertical  Section  through  the  Carti- 
lage and  incipient  Done  of  the  diaphysia 
of  the  Femur,  in  an  Infant  a  fortnight 
old :  a,  cartilage-cells  arranged  in  lon- 
gitudinal piles  near  the  ossified  surface ; 
b,  plane  of  ossification,  the  osseous  mat- 
ter inclosing  the  bases  of  the  piles ;  c, 
close  osseous  network  first  formed ;  d, 
cancellated  structure  formed  by  the  ab- 
sorption of  parts  of  this ;  e,  its  cancelli, 
filled  with  medulla. 


Vertical  section  of  Cartilage  at  ttie  seat  of  Ossifica- 
tion ;  the  clusters  of  cells  are  arranged  in  columns, 
the  intercellular  spaces  between  them  being  1- 
3250th  of  an  inch  in  breadth.  At  the  lower  end  of 
the  figure,  osseous  fibres  are  seen  occupying  the 
intercellular  spaces,  at  first  bounding  the  clusters 
laterally,  then  splitting  them  longitudinally  and 
encircling  each  separate  cell.  The  greater  opacity 
of  this  portion  is  due  to  a  threefold  cause ;  the  in- 
crease of  osseous  fibres,  the  opacity  of  the  contents 
of  the  cells,  and  the  multiplication  of  oil-globules. 


DEVELOPMENT   OF   BONE.  275 

so  many  involutions  of  the  external  surface,  allow  the  vessels  to  come  into  nearer 
relation  with  the  interior  parts  of  the  cartilaginous  structure,  than  they  would 
otherwise  do.  They  are  especially  developed  at  certain  points,  which  are  to  be 
the  centres  of  the  ossifying  process ;  and  it  is  always  observable,  that  the  vascu- 
larity  is  greatest  at  the  zone  in  which  the  conversion  of  cartilage  into  bone  is 
actually  taking  place,  and  that  the  cartilage  cells  are  there  arranged  in  a  some- 
what radiating  manner  around  them  (Fig.  66).  During  the  extension  of  the 
vascular  canals  into  the  Cartilaginous  matrix,  certain  changes  are  taking  place 
in  the  substance  of  the  latter,  which  are  preparatory  to  its  conversion  into  Bone. 
Instead  of  single  isolated  cells,  or  groups  of  two,  three,  or  four,  such  as  we  have 
seen  to  be  characteristic  of  ordinary  Cartilage  (Fig.  51),  we  find,  as  we  approach 
the  plane  of  ossification  in  a  vertical  section,  clusters  made  up  of  a  larger  number 
arranged  in  a  linear  manner  (Figs.  67,  68) ;  which  seem  to  be  formed  by  a  con- 
tinuance of  the  same  multiplying  process  as  that  formerly  described  (§  104). 
And  when  we  pass  still  nearer,  we  see  that  these  clusters  are  composed  of  a  yet 
greater  number  of  cells,  which  are  arranged  in  long  rows,  whose  direction  cor- 
responds to  the  longitudinal  axis  of  the  bone ;  these  clusters  are  still  separated 
by  intercellular  substance ;  and  it  is  in  this,  that  the  ossific  matter  is  first  depo- 
sited. If  we  separate  the  cartilaginous  and  the  osseous  substance  at  this  stage 
of  the  process,  we  find  that  the  ends  of  the  rows  of  cartilage  cells  are  received 
into  deep,  narrow  cups  of  bone,  formed  by  the  calcification  of  the  intercellular 
substance  between  them  (Fig.  69).  Thus  the  Bone  first  formed  in  the  cartila- 

Fig.  69. 


First  Osseous  network  formed  in  the  intercellular  substance  of  Cartilage,  around  a  vascular  canal,  as  in  Fig  66. 

ginous  matrix,  is  seen  to  consist  of  a  series  of  lamellae  of  a  somewhat  cylindrical 
form ;  inclosing  oblong  areolae,  or  short  tubular  cavities,  within  which  the  piles 
of  cartilage  cells  yet  lie;  and  it  thus  corresponds  closely  with  thereticular  struc- 
ture, which  first  makes  its  appearance  in  the  intra-membranous  form  of  the 
process. — So  far,  it  would  appear  that  the  bloodvessels  are  not  directly  concerned 
in  the  operation;  for  although  they  advance  to  the  near  neighborhood  of  the 
first  ossific  deposit,  they  do  not  make  their  way  into  its  substance,  or  even  into 
the  intervening  areolae. 

265.  This  state  of  things,  however,  speedily  gives  place  to  another.  On 
examining  the  subjacent  portion,  in  which  the  ossification  has  advanced  further, 
it  is  found  that  the  original  closed  cavities  have  coalesced  to  a  certain  extent 
(probably  by  the  absorption  of  their  walls),  both  laterally  and  longitudinally 
(Fig.  70)  ;  and  that  they  now  form  a  cancellated  texture  (Fig.  67,  d),  the  areolse 
of  which  (e,  e)  receive  numerous  bloodvessels,  prolonged  into  them  from  the 
previously-ossified  portion.  The  groups  of  cartilage  cells  which  originally  occu- 


276 


OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 


pied  the  cavities,  are  no  longer  seen ;  and  their  place  is  filled  with  a  blastema, 
composed  of  cells  containing  a  granular  matter,  and  closely  resembling  those  seen 
in  the  intra-membranous  ossification,  with  a  few  fibres  scattered  amongst  them. 
It  is  by  a  change  in  this  blastema,  that  the  walls  of  the  cavities  are  gradually 

Fig.  70. 


Transverse  sections  of  growing  bone,  showing  the  lateral  coales- 
cence of  the  primary  bony  areolae  and  the  thickening  of  the  sides 
of  the  enlarged  cavities  by  new  osseous  deposit.  The  section  A  is 
made  almost  immediately  below  the  surface  of  ossification ;  B  is  some- 
what lower,  and  shows  the  cavities  still  more  enlarged,  and  their 
sides  more  thickened  than  in  A.  The  new  osseous  lining  is  transpa- 
rent, and  appears  light  in  the  figures ;  the  dark  ground  within  the 
areolae  is  owing  to  opaque  debris,  which  collected  there  in  grinding 
the  sections.  It  must  be  farther  noticed,  that  the  letter  A,  within 
the  larger  figure,  marks  a  place  where  a  bony  partition  had  been 
accidentally  broken  away,  so  that  the  large  space  was  naturally 
divided  into  two. 


consolidated ;  new  deposits  of  ossific  matter  being  formed  in  their  interior,  which 
occasion  the  gradual  contraction  of  the  cavities,  and  give  an  increasing  density 
to  the  bone.  The  cancellated  structure,  which  remains  for  a  time  in  the  interior 
of  the  long  bones,  and  which  continues  to  occupy  their  extremities,  represents 
the  early  condition  of  the  ossifying  substance,  with  very  little  change ;  whilst 
the  cavities  which  have  formed  more  regular  communications  with  each  other, 
and  which  have  been  gradually  contracted  by  the  subsequent  deposit  of  concentric 
lamellae,  one  within  another,  form  the  original  Haversian  canals.  Thus  we  see 
that  they  all  form  one  system  in  their  origin ;  as  they  may  be  considered  to  do, 
notwithstanding  the  difference  of  their  form,  in  the  complete  bone. 

266.  The  original  osseous  lamellae,  formed  by  the  consolidation  of  the  carti- 
laginous substance,  are  entirely  composed  of  granular  matter;  and  exhibit  none 
of  the  lacunae  and  canaliculi,  which  are  commonly  regarded  as  characteristic  of 
Bone.  These  excavations  present  themselves,  however,  in  all  the  subsequent 


DEVELOPMENT   OF   BONE.  277 

deposits ;  and  into  the  origin  of  these,  we  have  now  to  inquire. — According  to 
the  views  of  Messrs.  Todd  and  Bowman,  and  of  Mr.  Tomes  (Op.  cit.),  the  cells 
of  the  blastema  fill  themselves  with  ossific  matter,  except  at  the  points  occupied 
by  the  nuclei;  at  the  same  time,  they  become  flattened  against  the  walls  of  the 
canals,  and  their  nuclei  send  out  radiating  prolongations ;  so  that,  when  the 
calcification  of  the  cell  has  been  completed,  a  stellate  cavity  is  left  in  the  hard 
deposit,  which  is  occupied  by  the  granular  matter  of  the  nucleus.  The  centre 
of  this  cavity  forms  the  lacuna,  in  which  some  traces  of  the  original  granular 
matter  may  frequently  be  found  remaining;  whilst  its  prolongations  form  the 
canalicuU,  from  which  the  nuclear  matter  seems  afterwards  to  disappear  altogether. 
— By  Henle',  again,  it  is  considered  that  the  lacuna  is  a  cavity  left  in  the  centre 
of  a  cell,  which  has  been  partially  filled  up  by  the  deposition  of  calcifying  matter 
upon  the  internal  surface  of  its  wall ;  and  that  the  unequal  deposit  of  this  matter 
leaves  passages,  resembling  those  of  the  "  pore-cells"  of  plants,  which  constitute 
the  canaliculi. — It  is  justly  remarked,  however,  by  Dr.  Sharpey,  that  neither  of 
these  two  views  is  reconcilable  with  the  structure  of  ordinary  sound  bone :  in 
which  there  is  not  only  an  absence  of  any  vestiges  of  cell-boundaries,  limiting 
the  radiation  of  the  canaliculi  which  issue  from  each  lacuna ;  but  it  is  constantly 
to  be  observed,  that  the  canaliculi  of  one  lacuna  encroach  upon  the  areae  traversed 
by  those  of  the  next.  And  it  is  considered  by  Dr.  S.,  that  the  lacunae  and 
canaliculi  are  "  little  vacuities  left  in  the  tissue  during  the  deposition  of  the 
reticular  fibres,  as  open  figures  are  left  out  in  the  weaving  of  some  artificial  fabrics ; 
and  thus  that  the  apposition  of  the  minute  apertures  existing  between  the  reti- 
culations of  the  lamellae  gives  rise  to  the  canaliculi.  At  the  same  time  it  seems 
not  unlikely  that  a  cell  or  a  cell-nucleus  may  originally  lie  in  the  lacuna  or  central 
cavity,  and  perhaps  determine  the  place  of  its  formation."  (Op.  cit.,  p.  91,  vol.  i., 
Am.  ed.) — The  Author  has  been  led,  however,  from  his  own  observations,  to  con- 
sider with  Schwann,  that  each  lacuna,  with  its  system  of  radiating  canaliculi,  is 
one  entire  cell,  resembling  the  pigment-cells  of  Batrachia  (Fig.  87,  c7  c),  which 
send  out  stellate  prolongations  that  sometimes  inosculate  with  each  other;  and 
to  believe  that  these  prolongations  in  their  outward  growth  insinuate  themselves 
through  the  areolse  of  the  fibrous  basis,  whilst  it  is  undergoing  calcification,  after 
the  manner  in  which  the  rootlets  of  plants  extend  themselves  through  the  loosest 
parts  of  a  dense  soil.  For  he  has  traced  all  stages  of  gradation  between  the  simple 
rounded  cavities,  whose  correspondence  in  size  and  situation  with  the  cells  that 
are  scattered  in  the  midst  of  the  consolidating  blastema  leaves  scarcely  any  doubt 
of  their  identity  with  these,  and  the  lenticular  lacunae  with  numbers  of  canaliculi 
proceeding  from  them.1 — Whatever  may  be  the  precise  mode  of  the  production 
of  the  lacunae  and  canaliculi,  it  may  be  considered  as  a  well-established  fact,  that 
the  production  of  the  concentric  layers  of  osseous  substance  within  the  Haversian 
canals  takes  place  in  a  manner  that  more  closely  corresponds  with  the  intra-mem- 
branous,  than  with  the  intra-cartilaginous  form  of  osteogenesis;  and  that  thus 

1  The  independent  observations  of  Dr.  Leidy  of  Philadelphia  precisely  confirm  those  of 
the  Author  upon  this  point.  (See  the  "Proceedings  of  the  Philadelphia  Academy  of  Natu- 
ral Sciences,"  Nov.  1848).  [Dr.  Leidy  was  led  to  adopt  the  views  of  Schwann,  in  relation 
to  the  development  of  the  lacunae  or  Purkinjean  corpuscles,  from  some  observation  made 
by  him  upon  the  process  of  ossification  in  the  os  frontis  of  a  human  embryo,  measuring 
two  inches  from  heel  to  vertex.  According  to  this  observer,  each  half  of  the  os  frontis 
at  this  period  presents  a  network  of  osseous  tissue,  which  is  thickest  and  most  developed 
along  the  curve  of  the  supra-orbitar  ridge,  and  the  frontal  and  orbitar  portions  are  nearly 
on  a  plane  with  each  other.  When  examined  by  means  of  the  microscope,  the  interspaces, 
or  meshes  of  the  osseous  tissue  are  discovered  to  be  filled  with  cartilage  cells  contained 
in  a  transparent  matrix  or  hyaline  substance  (Fig.  70*,  b).  The  cells  are  isolated  from 
each  other,  granular  in  structure,  and  contain  a  large  granular  nucleus,  within  which 
may  be  detected  a  translucent  nucleolus.  The  cells  contents  are  colored  brown  by  iodine, 


278 


OP   THE   PRIMARY   TISSUES   OP   THE   HUMAN   BODY. 


it  is  only  with  the  very  first  stage  of  the  process,  that  the  cartilaginous  matrix 
has  any  concern.1 

267.  In  the  formation  of  a  long  bone  (Fig.  71),  we  usually  find  one  centre  of 
ossification  in  the  shaft,  and  one  in  each  of  the  epiphyses;  in  the  flat  bones, 
there  is  one  in  the  middle  of  the  surface,  and  one  in  each  of  the  principal  pro- 
cesses. The  ossification  usually  proceeds  to  a  considerable  extent,  however,  in 
the  main  centre,  before  it  commences  in  the  extremities  or  processes ;  and  these 
remain  distinct  from  the  principal  mass  of  the  bone,  long  after  this  has  acquired 
solidity.  During  the  spread  of  the  ossifying  process,  the  cartilaginous  matrix 
continues  to  grow,  like  cartilage  in  other  parts;  but  after  the  bony  deposit  has 
pervaded  its  entire  substance,  in  the  manner  just  described,  a  change  takes  place 
in  the  method  adopted.  The  osseous  laminae,  that  subdivide  the  whole  texture, 
are  removed  by  absorption  from  the  interior  of  the  shaft,  so  as  to  leave  the  great 
central  medullary  cavity ;  whilst  on  the  other  hand,  they  receive  progressive 
additions  in  the  external  portion,  which  is  thus  gradually  consolidated  into  the 
dense  bone,  that  forms  the  hollow  cylinder  of  the  shaft.  This  consolidation  is 
effected  by  the  deposit  of  a  series  of  concentric  laminae,  one  within  another,  on 
the  lining  of  the  Haversian  canals. — The  bone  continues  to  increase  in  diameter, 
by  the  formation  of  new  layers  upon  its  exterior ;  and  Dr.  Sharpey  has  pointed 

Fig.  70.*  whilst   the   translucent   intercellular    matrix  remains    un- 

changed. The  average  diameter  of  the  cartilage  corpuscle  is 
about  yg'g-ffth  of  an  inch  and  the  nucleus  yyyyth  of  an  inch. 
Upon  examining  this  border  of  the  bone,  Dr.  Leidy  noticed 
a  system  of  reticulated  osseous  fibres  proceeding  from  the 
primitive  ossific  rete  into  the  intercellular  substance  of  the 
cartilage  cells,  apparently  by  a  deposit  of  earthy  salts,  in  a 
linear  direction.  In  such  position,  he  observed  the  cartilage 
cells  had  already  protruded,  or  had  connected  with  them, 
the  canaliculi ;  and  these  appear  at  this  time  only,  because, 
several  cells  (Fig.  70*,  e),  noticed  at  the  edge  of  the  primitive 
bony  rete,  and  partly  enveloped  in  the  osseous  deposit,  had 
the  canaliculi  passing  into  the  latter,  whilst  on  the  unossified 
or  cartilaginous  side,  none  had  yet  been  developed,  The  cell 
wall  has  until  now  apparently  remained  unchanged,  but  com- 
mences to  blend  or  fuse  itself  with  the  intercellular  substance, 
and  with  the  secondary  osseous  fibrillae.  The  Purkinjean  cor- 
puscles, or  lacunae  (d),  which  are  perfectly  formed  in  the  osse- 
ous structure,  at  this  time  have  the  same  diameter,  or  nearly 
so,  as  the  cartilage  corpuscle  from  which  they  originated,  and 
they  still  contain  a  granular  nucleus,  readily  brought  into 
view  by  iodine,  which  corresponds  to  that  of  the  cartilage  cor- 
puscle, and  has  about  the  same  measurement.  At  a  later 
period  the  nucleus  of  the  Purkinjean  corpuscle  appears  to 
dissolve  away.* — ED.]  The  various  gradations  of  the  calci- 
fying process  in  a  fibrous  tissue  may  be  very  well  seen  in  the 
ossified  tendons  of  the  legs  of  many  Birds. 

Represents  a  portion  of  the  border  of  the  os  frontis  from  a  human  embryo,  measuring  two  inches  in  length, 
very  highly  magnified,  a.  Portion  of  the  ossified  rete.  b.  Cartilage  of  one  of  the  interspaces,  c.  Cartilage 
cells,  with  their  nuclei,  d.  Newly  formed  Purkinjean  corpuscles  still  containing  the  nucleus,  e,  A  cell  partly 
enveloped  in  the  deposit  of  the  osseous  salts.  (From  Nature,  by  J.  L.) 

1  The  account  recently  given  by  Prof.  Kolliker  of  the  formation  of  the  lacunae,  &c.  is 
too  much  founded,  as  it  appears  to  the  Author,  upon  observations  made  upon  an  abnormal 
mode  of  it,  which  cannot  be  taken  as  the  criterion  of  the  healthy  process.  (See  g  269.) 
Some  criticisms  upon  Prof.  K's  views  will  be  found  in  the  "Brit,  and  For.  Med.  Chir. 
Rev.,"  Jan.  1852. 


*  Sharpey  and  Quain,  Anutoiuy.  Edited  by  Leidy,  vol.  i.  p.  91,  Am.  El. 


DEVELOPMENT   OP   BONE 


279 


out  that  these  layers  are  formed,  not  (as  usually  stated)  in  a  cartilaginous 
matrix,  but  in  the  substance  of  a  membrane  that  intervenes  between  the  proper 
periosteum  and  the  surface  of  the  bone,  consisting  of  fibres  and  granular  cells, 
and  exactly  resembling  that  in  which  the  flat  bones  of  the  roof  of  the  skull  are 
developed  (Fig.  64).  The  basis  of  this  sub-periosteal  tissue  has  been  shown  by 


Fig.  71. 


Fig.  72. 


Ossification  of  foetal  humerus,  Subperiosteal  layer  from  the  extremity  of  the  bony 

natural  size,  the  upper  half  di-  shaft  of  the  ossifying  tibia.    The  cartilage  and  more  open 

Tided  longitudinally;  a,  cartilage,  bony  tissue,  have  been  scraped  off  from  the  inside  of  the 

•with  vascular  canals ;  fc,  termina-  crust  except  at  a,  where  a  dark  shade  indicates  a  few 

tion  of  bony  deposit  in  the  shaft.  vertical  osseous  areolae  out  of  focus  and  indistinctly  seen. 

The  part  a,  &,  of  the  crust  is  ossified,  between  6  and  c  are 
the  clear  reticulated  fibres  into  which  the  earthy  deposit 
is  advancing.  Magnified  150  diameters. 

Scherer  not  to  be  chondrin,  but  glutin ;  consequently  it  has  no  title  whatever  to 
the  designation  of  cartilage,  which  some  have  applied  to  it.  The  Haversian 
canals,  too,  of  these  new  layers,  are  formed  in  the  same  manner  as  those  of  the 
tabular  bones  of  the  skull ;  the  osseous  matter  being  not  only  laid  on  in  strata 
parallel  to  the  surface,  but  also  being  deposited  around  processes  of  the  vascular 
membranous  tissue,  which  extend  obliquely  from  the  surface  into  the  substance 
of  the  shaft ;  the  channels,  in  which  these  membranous  processes  lie,  becoming 
narrowed  by  the  deposition  of  concentric  osseous  laminae,  and  at  last  remaining 
as  the  Haversian  canals.  Whilst  this  new  deposition  is  taking  place  on  the 
exterior  of  the  shaft,  absorption  of  the  inner  and  older  layers  goes  on ;  so  that 
the  central  cavity  is  proportionably  enlarged.  The  increase  of  the  bone  in  length 
appears  due  to  the  growth  of  the  cartilage  between  the  shaft  and  the  epiphyses, 
so  long  as  this  remains  unconsolidated  by  ossific  deposit ;  and  this  state  continues, 
until  the  bone  has  acquired  nearly  its  full  dimensions.  What  further  increase 
it  gains,  seems  chiefly  if  not  entirely  due  to  the  progressive  ossification  of  the 
articular  cartilage  covering  the  extremities;  which  progressively  diminishes  in 
thickness  during  the  whole  of  life,  and  which  in  old  age  sometimes  appears  to 
have  been  almost  completely  converted  into  bone. 


280  OF   THE   PRIMARY   TISSUES   OF   THE    HUMAN   BODY. 

268.  It  thus  appears  that  there  is  no  true  interstitial  growth  in  Bone ;  that 
is,  the  parts,  through  which  the  ossific  process  has  made  its  way,  are  incapable 
of  any  further  extension  than  by  addition  to  their  surface.     By  the  admirable 
system  of  prolongations,  however,  by  which  the  vascular  membrane  is  conveyed 
into  its  intimate  substance,  we  find  this  method  of  superficial  deposit  adapted  to 
the  consolidation  of  parts  which  are  at  first  sketched  out  (as  it  were)  by  a  slight 
osseous  reticulation ;  whilst  by  the  facility  with  which  the  bony  matter  is  absorbed 
in  the  internal  part  of  the  shaft,  at  the  same  time  that  it  is  being  deposited  on 
its  exterior,  the  same  effect  is  produced,  as  if  the  whole  cylinder  could  enlarge 
uniformly  by  a  proper  interstitial  growth,  in  the  manner  of  the  softer  tissues. — 
Much  of  our  information  regarding  the  mode  in  which  new*osseous  matter  is  de- 
posited, is  derived  from  observations  made  upon  the  bones  of  animals  that  have 
been  fed  with  madder;  for  this  coloring  matter,  having  a  strong  affinity  for  bone- 
earth,  tinges  all  those  parts  which  are  in  close  relation  with  the  vascular  surfaces. 
In  very  young  animals,  a  single  day  serves  to  color  the  entire  substance  of  the 
bones  ;  for  there  is  in  them  no  osseous  matter  far  removed  from  a  vascular  sur- 
face.    At  a  later  period,  however,  the  coloring  matter  is  deposited  less  rapidly ; 
and  is  found  to  be  confined  to  the  innermost  of  the  concentric  laminae  of  bone 
surrounding  each  Haversian  canal,  showing  that  this  is  the  last  formed.     When 
madder  is  given  to  a  growing  animal,  the  external  portion  of  the  shaft  is  first 
reddened ;  showing  that  the  new  formation  takes  place  exclusively  in  that  situa- 
tion.    And  if,  when  time  has  been  allowed  for  this  part  to  become  tinged,  the 
administration  of  the  madder  be  discontinued,  and  the  animal  be  killed  some 
weeks  afterwards,  the  red  stratum  is  surrounded  by  a  colorless  one  of  subsequent 
formation;  whilst  the  colorless  layer  internal  to  the  red  one,  and  formed  previ- 
ously to  it,  is  thinned  by  absorption  from  within.     By  alternately  administering 
and  withholding  the  madder,  a  succession  of  colored  and  colorless  cylinders  may 
thus  be  formed  in  the  shaft  of  a  long  bone ;  which  present  themselves  as  concen- 
tric rings  in  its  transverse  section. 

269.  The  nature  of  the  Ossifying  process  receives  some  additional  light  from 
the  abnormal  forms,  in  which  it  occasionally  presents  itself  in  Cartilages  that 
are  usually  permanent ;  as  well  as  in  various  Fibrous  tissues,  such  as  the  coats 
of  the  arteries,  fibrous  and  serous  membranes,  muscular  substance,  &c. ;  and 
also  in  the  development  of  Tumors.     In  most  of  these  cases,  the  ossific  deposit 
may  often  be  seen  to  take  place,  in  the  first  instance,  in  the  form  of  distinct 
granules,  which  gradually  coalesce ;  or  in  the  form  of  spicular  fibres,  to  which 
additions  are  progressively  made,  until  a  solid  mass  is  produced.     This  adven- 
titious bone,  however,  almost  invariably  differs  from  true  or  normal  bone,  in 
the  want  of  a  regular  Haversian  system  with  concentric  laminae,  and  in  the 
absence  or  imperfect  production  of  the  characteristic  lacunae  and  canaliculi. 
Irregular  cavities,  however,  are  scattered  through  them,  which  may  in  some  de- 
gree answer  the  same  purpose ;  and  these,  in  osseous  tumors  which  had  origi- 
nally a  Cartilaginous  basis,  may  often  be  plainly  seen  to  be  the  persistent  carti- 
lage cells,  or  the  nuclei  of  cartilage  cells,  the  intervening  substance  having 
undergone  calcification  and  gradually  inclosed  them.     It  is  curious  that  in  certain 
abnormal  Cartilaginous  growths,  the  nuclei  have  a  stellate  form,  and  the  cartilage 
cells  become  fused  with  the  surrounding  basis-substance ;  so  that,  when  the  latter 
is  calcified,  the  inclosed  stellate  nuclei  present  a  strong  resemblance  to  the  normal 
lacunae  and  canaliculi  of  bone.1     But  it  may  be  stated  as  a  well-established  fact, 
that  calcified  tissues,  having  a  more  or  less  close  resemblance  to  true  Bone,  may  be 
produced  in  a  great  variety  of  modes ;  and  no  inference  can  be  fairly  drawn  from 
such  observations,  therefore,  in  regard  to  the  normal  process  of  Osteogenesis.    For 

1  See  Mr.  Paget's  "Lectures  on  Tumors,"  in  "Medical  Gazette,"  Aug.  8,  1851. 


REPARATION   OF   BONE.  281 

Osseous  tissue,  though  of  a  very  imperfect  kind,  is  often  formed  in  the  substance 
of  Fibrous  tumors,  by  the  calcification  of  their  organic  base ;  and  it  is  curious 
that  this  should  usually  contain  a  very  large  proportion  of  calcareous  matter, 
as  much  as  81  £  per  cent,  having  been  found  in  a  specimen  transmitted  to  John 
Hunter  as  a  calculus,  and  the  proportion  of  carbonate  of  lime  being  much 
greater  than  in  normal  bone.  Where  perfected  Osseous  structure  presents  itself 
in  a  Tumor,  it  is  usually  as  an  outgrowth  from  true  Bone.  It  is  curious,  how- 
ever, that  the  osseous  plates  not  unfrequently  found  in  the  dura  mater,  possess 
a  structure  (as  pointed  out  by  Mr.  Tomes,  loc.  cit.)  much  more  closely  allied  to 
that  of  true  bone,  than  that  which  presents  itself  in  most  adventitious  forma- 
tions of  this  kind ;  and  this  seems  related  to  the  fact,  that,  in  some  of  the  lower 
Mammalia,  especially  of  the  Carnivorous  order,  certain  parts  of  this  membrane 
(the  falx  and  tentorium)  are  normally  ossified. 

270.  The  Regeneration  of  Bone,  after  loss  of  its  substance  by  disease  or 
injury,  is  extremely  complete;  in  fact,  there  is  no  other  structure  of  so  complex 
a  nature,  which  is  capable  of  being  so  thoroughly  repaired.     Much  discussion 
has  taken  place,  with  respect  to  the  degree  in  which  the  different  membranous 
structures,  that  surround  bone  and  penetrate  its  substance,  contribute  to  its 
regeneration ;  but  the  fact  seems  to  be,  that  any  or  all  these  membranes  may 
contribute  to  the  formation  of  new  bone,  in  proportion  to  their  vascularity — the 
new  structure,  however,  being  most  readily  produced  in  continuity  with  the  old. 
Thus,  when  a  portion  of  the  shaft  of  the  bone  is  entirely  removed,  but  the  peri- 
osteum is  left,  the  space  is  filled  up  with  bony  matter  in  the  course  of  a  few 
weeks ;  though,  if  the  periosteum  also  be  removed,  the  formation  of  new  osseous 
matter  will  be  confined  to  a  small  addition  in  a  conical  form  to  the  two  extremi- 
ties, a  large  interspace  being  left  between  them.     The  production  of  new  bony 
tissue,  in  this  experiment,  as  in  cases  where  the  periosteum  has  been  detached 
by  disease,  and  remains  alive  while  the  shaft  dies,  is  in  continuity  with  minute 
spicula  of  original  bone,  which  still  adhere  to  the  membrane;  and  it  is  well 
known  that,  in  comminuted  fractures,  every  portion  of  the  shattered  bone  that 
remains  connected  with  the  vascular  membranes,  whether  these  be  internal  or 
external,  becomes  the  centre  of  a  new  formation;  the  loss  of  substance  being 
filled  up  the  more  rapidly  in  proportion  to  the  number  of  such  centres. 

271.  The  most  extensive  reparation  is  seen,  when  the  shaft  of  a  long  bone  is 
destroyed  by  disease.     If  violent  inflammation  occur  in  its  tissue,  the  death  of 
the  fabric  is  frequently  the  consequence;  apparently  through  the  blocking  up  of 
the  canals  with  the  products  of  inflammatory  action,  and  the  consequent  cessa- 
tion of  the  supply  of  nutriment.     It  is  not  often  that  the  whole  thickness  of 
the  bone  becomes  necrosed  at  once ;  more  commonly  this  result  is  confined  to 
its  outer  or  to  its  inner  layers.     When  this  is  the  case,  the  new  formation  takes 
place  from  the  part  that  remains  sound ;  the  external  layers,  which  receive  their 
vascular  supply  from  the  periosteum,  and  from  the  Haversian  canals  continued 
inwards  from  it,  throwing  out  new  matter  on  their  interior,  which  is  gradually 
converted  into  bone;  whilst  the  internal  layers,  if  they  should  be  the  parts  remain- 
ing uninjured,  do  the  same  on  their  exterior,  deriving  their  materials  from  the 
medullary  membrane,  and  from  its  prolongations  into  the  Haversian  canals. 
But  it  sometimes  happens  that  the  whole  shaft  suffers  necrosis;  and  as  the 
medullary  membrane  and  the  entire  Haversian  system  have  lost  their  vitality, 
reparation  can  then  only  take  place  from  the  splinters  of  bone  which  may  remain 
attached  to  the  periosteum,  and  from  the  living  bone  at  the  two  extremities. 
This  is  consequently  a  very  slow  process;  more  especially  as  the  epiphyses  hav- 
ing been  originally  formed  as  distinct  parts  from  the  shaft,  do  not  seem  able  to 
contribute  much  to  the  regeneration  of  the  latter. 

272.  When  the  shaft  of  a  long  bone  of  a  dog,  rabbit,  or  bird  has  been  fractured 


282  OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 

through,  and  the  extremities  have  been  brought  evenly  together,  it  is  found  that 
the  new  matter  first  ossified  is  that  which  occupies  the  central  portion  of  the 
deposit,  and  which  thus  connects  the  medullary  cavities  of  the  broken  ends, 
forming  a  kind  of  plug  that  enters  each.  This  was  termed  by  Dupuytren,  by 
whom  it  was  first  distinctly  described,  the  provisional  callus ;  and  it  serves  to 
hold  the  bones  together  during  the  formation  of  the  permanent  callus,  which  passes 
directly  between  the  fractured  surfaces,  and  which  usually  requires  a  much  longer 
time  for  its  production.  After  this  more  direct  union  has  been  established,  the 
provisional  callus  is  gradually  absorbed,  and  the  continuity  of  the  medullary 
canal  is  thus  restored,  in  the  manner  in  which  it  was  first  established.  These 
statements  do  not  apply  to  Man,  however,  without  great  modification.  For,  as 
Mr.  Paget  has  pointed  out,1  it  is  very  rare  to  find  a  true  provisional  callus  unit- 
ing the  fractured  ends  of  a  human  bone ;  and  since,  where  this  does  present 
itself,  as  in  the  ribs,  and  occasionally  in  the  clavicle,  the  two  broken  ends  are  in 
a  state  of  continual  movement,  we  are  probably  to  attribute  its  absence  in  other 
cases  to  the  maintenance  of  quietude  and  more  perfect  apposition.  Mr.  Gulli- 
ver has  remarked2  that,  when  the  broken  portions  of  bone  form  an  angle,  there 
is  quite  a  distinct  centre  of  ossification  in  the  new  matter,  from  which  that  por- 
tion of  it  is  ossified,  that  lies  between  the  sides  of  the  angle ;  thus  forming  what 
has  been  termed  an  accidental  callus,  and  giving  support  to  the  two  portions 
of  the  shaft,  in  a  situation  which  is  exactly  that  of  the  greatest  mechanical 
advantage.  Though  for  some  time  quite  unconnected  with  the  old  bone,  it  soon 
becomes  united  to  the  regular  callus.  This  instance  proves,  that  continuity  with 
previously-formed  bone  is  not  absolutely  requisite  for  the  production  of  new 
osseous  structure ;  although  the  process  is  decidedly  favored  thereby. 

273.  The  production  of  new  Osseous  tissue,  after  disease  or  injury,  seems 
to  take  place  upon  a  plan  essentially  the  same  as  its  original  formation.  A 
plastic  or  organizable  exudation  is  first  poured  out  from  the  neighboring  blood- 
vessels ;  and  this  nucleated  blastema  may  itself,  according  to  Mr.  Paget's  observ- 
ations,3 undergo  conversion  into  bone,  without  any  intermediate  stage ; — a 
finely-granular  osseous  deposit  taking  place  in  the  blastema,  and  gradually  accu- 
mulating so  as  to  form  the  delicate  yet  dense  lamellae  of  fine  cancellous  tissue ; 
and  the  nuclei  apparently  giving  origin  to  the  osseous  lacunse  and  canaliculi. 
But  where  this  simplest  form  of  the  process  does  not  take  place,  the  nucleated 
blastema  gives  origin  either  to  a  cartilaginous  or  to  a  fibrous  structure,  or  to  a 
combination  of  both.  The  former  seems  more  common  among  the  lower  animals, 
especially  when  they  are  young,  than  it  is  in  Man  ;  when  it  occurs,  the  cartilage 
is  converted  into  bone  after  the  usual  manner.  In  older  animals,  however,  the 
new  structure  appears  to  be  rather  of  a  fibrous  character ;  and  the  ossifying  pro- 
cess would  therefore  correspond  rather  with  that,  by  which  the  normal  increase 
of  their  bones  is  effected.  Mr.  Tomes  states4  that  he  has  examined  various  cases 
of  fracture  of  the  neck  or  shaft  of  the  femur,  in  which  union  has  not  been 
effected,  in  consequence  of  the  patient's  advanced  age;  and  that  he  found  in 
these  no  intervening  cartilage,  and  but  a  scanty  amount  of  condensed  areolar 
tissue.  In  this  latter,  traces  of  an  attempt  at  repair  may  be  generally  found,  in 
the  presence  of  osseous  matter  in  granules  or  granular  masses ;  but  in  these  there 
is  no  arrangement  of  tubes  or  bones-cells  of  definite  character;  indeed,  such 
osseous  masses  are  generally  small,  and  are  deficient  in  density,  owing  to  the 
want  of  union  between  the  individual  granules. 

274.  The  Teeth  are  nearly  allied  to  Bone  in  structure;  and  in  some  of  the 

1  "Lectures  on  Repair  and  Reproduction,"  in  "Medical  Gazette,"  July  20,  1849,  p. 
116. 

2  "Edinb.  Med.  and  Surg.  Journal,"  vol.  xlvi.  p.  313. 
9  Op.  cit,  pp.  120,  121. 

«  "Cyclopsedia  of  Anatomy  and  Physiology,"  vol.  iii.  p.  857. 


STRUCTURE  OF  TEETH. — DENTINE. 


283 


Fig.  73. 


lower  Vertebrata,  there  is  an  actual  continuity  between  the  bone  of  the  jaw 
and  the  teeth  projecting  from  it,  notwithstanding  that  the  latter  form  part  of 
the  dermal  skeleton,  whilst  the  former  belongs  to  the 
neural  or  internal.  In  Man  and  the  higher  animals, 
however,  there  is  an  obvious  difference  in  their  struc- 
ture, as  in  their  mode  of  development.  These  sub- 
jects have  lately  received  much  attention;  and  the 
practical  importance  of  an  acquaintance  with  them, 
renders  it  desirable  that  they  should  be  here  treated 
somewhat  fully. — The  Teeth  of  Man,  and  of  most  of 
the  higher  animals,  are  composed  of  three  very  dif- 
ferent substances ;  Dentine  (known  as  ivory  in  the 
tusk  of  the  Elephant),  Enamel,  and  Cementum  or 
Crusta  Petrosa.  These  are  disposed  in  various 
methods,  according  to  the  purpose  which  the  Tooth 
is  to  serve :  in  Man,  the  whole  of  the  crown  of  the 
tooth  is  covered  with  Enamel  (Fig.  73,  1) ;  its  root 
or  fang  is  covered  with  Cementum  (2,  7),  whilst  the 
substance  or  body  of  the  tooth  is  composed  of  Den- 
tine (3).  In  the  molar  Teeth  of  many  Herbivorous 
animals,  however,  the  Enamel  and  Cementum  form 
vertical  plates,  which  alternate  with  plates  of  Den- 
tine, and  present  their  edges  at  the  grinding  surface 
of  the  tooth ;  and  the  unequal  wear  of  these  sub- 
stances— the  Enamel  being  the  hardest,  and  the  Ce- 
mentum the  softest — occasions  this  surface  to  be  al- 
ways kept  rough. 

275.  The  Dentine*  consists  of  a  firm  substance,  in  which  mineral  matter  largely 
predominates,  though  to  a  less  degree  than  in  the  enamel.     It  is  traversed 
by  a  vast  number  of  very  fine  cylindrical,  branching,  wavy  tubuli  j  which  corn- 
Fig.  74. 


Vertical  section  of  Human  Molar 
Tooth :  1,  enamel ;  2,  7,  cementum 
or  crusta  petrosa;  3,  dentine  or 
ivory ;  4,  osseous  excrescence,  aris- 
ing from  hypertrophy  of  cemen- 
tum ;  5,  cavity ;  6,  osseous  cells  at 
outer  part  of  dentine. 


Section  through  the  fang  of  a  Molar  Tooth :  a,  a,  dentine  traversed  by  its  tubuli ;  b,  b,  nodular  layer ;  c,  c, 

cementum. 

mence  at  the  pulp-cavity  (on  whose  wall  their  openings  may  be  seen),  and  radiate 
towards  the  surface  (Fig.  74,  a  a).     In  their  course  outwards,  the  tubuli  occa- 

1  A  structure  exactly  resembling  Dentine  has  been  found  by  the  Author  in  the  shell  of  the 
Crab,  especially  at  the  tips  of  the  claws ;  and  a  less  regular  structure  of  the  same  kind  in 
the  shells  of  many  Mollusca.  ("Princ.  of  Phys.,  Gen.  and  Comp.,"  |g  197,  199,  Am.  Ed.) 


284 


OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 


Fig. 


sionally  divide  dichotomously;  and  they  frequently  give  off  minute  branches, 
which  again  send  off  smaller  ones.  These  branchings  are  more  frequent,  the 
nearer  the  tubes  approach  the  exterior  of  the  dentine;  and  indeed  it  is  only  in 
the  immediate  neighborhood  of  the  enamel,  that  the  dentinal  tubes  of  the  crown 
of  the  human  tooth  usually  begin  to  ramify,  although  those  of  the  neck  and 
fang  give  off  branches  about  the  middle  of  their  course.  The  terminal  branches, 
on  their  arrival  at  the  line  of  junction  between  the  dentine  and  enamel,  some- 
times recurve  and  anastomose  with  contiguous  tubes,  sometimes  pass  across  the 
line  of  junction  and  extend  themselves  for  a  short  distance  into  the  enamel 
(as  first  noticed  by  Mr.  Tomes),1  and  sometimes  end  in  a  fine  point  or  in  a 
rounded  dilatation.  In  the  fang  of  the  tooth,  there  is  a  much  more  frequent 
anastomosis  among  the  tubuli;  and  of  their  terminal  branches,  some  lose  them- 
selves in  their  intertubular  tissue,  others  dilate  into  radiating  cells  not  unlike 
those  of  the  cementum,  others  anastomose  and  form  loops  with  the  branches  of 
adjacent  tubes,  whilst  others  pass  into  the  interspaces  that  exist  among  the  large 

granules  that  form  the  outer  surface 
of  the  dentine  of  the  fang  (Fig.  74,  b 
6),  and  some  of  these  may  even  ex- 
tend themselves  into  the  cementum 
and  communicate  with  its  radiating 
cells.  When  the  dentinal  tubuli  are 
examined  in  transverse  section  (Fig. 
75),  the  aperture  of  each  is  seen  to  be 
surrounded  by  an  annulus,  which  se- 
parates its  parietes  from  the  intertu- 
bular tissue  ;  and  it  can  be  further  seen, 
better  in  transverse  than  in  longitu- 
dinal sections,  that  the  distances  of 
the  tubuli  from  each  other  vary  great- 
ly; the  tubuli  being  closest,  and  the  intertubular  tissue  consequently  the  small- 
est in  amount,  in  the  crown  of  the  tooth  (A)  ;  whilst  in  the  dentine  of  the  fang 
the  intertubular  tissue  forms  the  larger  element  (B).  The  internal  diameter  of 
the  tubuli  in  their  largest  part  averages  about  1-10, 000th  of  an  inch;  but  when  their 
parietes  are  included,  it  measures  about  3-10,OOOth;  their  smallest  branches  are 
immeasurably  fine.  The  intertubular  tissue  of  dentine,  as  of  bone,  is  affirmed 
by  Mr.  Tomes  to  be  granular  throughout;  the  granules  being  nearly  spherical, 

and  measuring  from  1  to  3-10,OOOths.  Near  the 
surface  of  the  dentine  in  the  fang,  and  occasionally 
in  other  parts  of  the  tooth,  it  presents  the  appear- 
ance of  an  aggregation  of  nodular  concretions,  with 
irregular  interspaces  between  them  (Fig.  74,  b  b) ; 
each  of  these,  when  divided  transversely  and 
highly  magnified,  is  seen  to  be  traversed  by  se- 
veral dentinal  tubes  (Fig.  76).  In  other  parts  of 
the  tooth,  it  not  unfrequently  happens  that  the 
dentinal  substance  is  traversed  by  lines  which 
divide.it  into  more  or  less  regular  polygonal  areae; 
and  this  appearance,  which  is  normal  in  the  teeth 
of  many  of  the  lower  animals,  is  considered  by 
Prof.  Owen  as  indicative  of  the  persistence  of  the 
boundaries  of  the  original  cells  of  the  pulp.  A  more  satisfactory  explanation 

1  See  his  "Lectures  on  Dental  Physiology  and  Surgery,"  p.  35.  Mr.  Tomes  has  since 
shown  that  the  passage  of  the  dentinal  tubes  into  the  Enamel,  in  large  numbers,  and  for 
a  considerable  distance,  is  a  distinctive  character  of  the  teeth  of  Marsupialia.  "Philos- 
Transact,,"  1849. 


Transverse  sections  of  Dentine  ;  |,  from  the  crown; 
B,  from  the  fang ;  showing  the  orifices  of  the  tubes,  and 
the  thickness  of  their  walls. 


Fig.  76. 


Portion  of  the  nodular  layer  of  the 
Dentine  oftticfang,  more  highly  mag- 
nified. 


STRUCTURE   OF   TEETH. — ENAMEL. 


285 


of  it  is  afforded,  however,  by  Mr.  Tomes' s  researches  on  the  development  of 
dentine  (§  213). — The  Dentinal  tubuli  are  far  too  minute  to  receive  blood;  but 
it  may  be  surmised  that,  like  the  canaliculi  of  bone,  they  absorb  matter  from 
the  vascular  lining  of  the  pulp-cavity,  which  aids  in  the  nutrition  of  the  tooth. 
Although,  when  once  fully  formed,  the  Tooth  undergoes  little  or  no  change,  there 
is  evidence  that  it  possesses  a  certain  power  of  repairing  the  effects  of  disease; 
a  new  layer  of  hard  matter  being  sometimes  thrown  out  on  a  surface,  which  has 
been  laid  bare  by  Caries.  It  has  been  found,  too,  that  the  Dentine  is  sometimes 
tinged  by  coloring  matters  contained  in  the  blood.  This  is  most  evident,  when 
a  young  animal  is  fed  upon  madder,  during  the  period  of  the  formation  of  the 
tooth;  but  even  in  an  adult,  some  tinge  will  result  from  a  prolonged  use  of  this 
substance;  and  it  has  been  noticed  that  the  teeth  of  persons,  who  have  long 
suffered  from  Jaundice,  sometimes  acquire  a  tinge  of  bile. — The  pulp-cavity  is 
sometimes  the  seat  of  a  secondary  development  of  dentinal  substance  by  which 
its  cavity  is  greatly  contracted,  or  even  obliterated.  This  is  seen  especially  in 
the  teeth  of  old  persons,  or  in  those  which  have  been  much  worn;  and  also  in 
those  that  are  the  subjects  of  caries,  a  layer  of  "secondary  dentine"  being 
formed  between  the  soft  pulp,  and  the  spot  towards  which  the  disease  is  advancing. 
This  "secondary"  dentine  is  not  so  regular  in  its  structure  as  the  "primary," 
and  more  resembles  that  of  the  lower  animals;  for  it  is  usually  traversed  by 
"vascular  canals"  proceeding  from  the  pulp-cavity,  and  the  tubuli  radiate  from 
these,  instead  of  from  one  common  centre.  Moreover,  the  presence  of  stellate 
lacunae,  resembling  those  of  bone,  is  much  more  common  in  this  substance  than 
in  true  dentine;  so  that,  both  in  the  presence  of  the  vascular  canals  which  re- 
present the  Haversian,  and  also  in  its  own  texture,  this  substance  may  be  con- 
sidered as  intermediate  between  Dentine  and  Bone. 

276.  The  Enamel  (Fig.  77)  is  composed  of  solid  prisms  or  fibres  (Fig.  78,  B), 
from  about  l-5600th  to  l-3300th 

of  an  inch  in  diameter,  arranged  Fig.  77. 

side  by  side,  and  closely  adherent 
to  each  other;  their  direction  is  for 
the  most  part  vertical  to  that  of  the 
dentinal  surface  on  which  they  rest, 
so  that  their  length  corresponds 
with  the  thickness  of  the  layer 
which  they  form ;  and  the  two  sur- 
faces of  this  layer  present  the  ends 
of  the  prisms,  which  are  usually 
more  or  less  regularly  hexagonal 
(Fig.  78,  A).  The  course  of  these 
prisms  is  generally  wavy  (Fig.  77), 
but  their  curves  are  for  the  most 
part  parallel  to  each  other;  not 
unfrequently,  however,  the  curves 
separate  from  each  other,  or  even 
decussate,  the  intervening  spaces 
being  then  filled  in  with  shorter 
fibres.  The  enamel-prisms  are 
usually  marked  by  transverse  stride 
(Figs.  77,  78,  B),  the  distance  of 
which  is  about  equal  to  the  dia- 
meter of  the  fibre;  these  appear 
to  be  indications  of  the  partitions 
between  the  longitudinally-joined  A>  TransTerse  section  of  J&iaMd>  ghowing  the  hexagonal 

Cells,   by    whose    coalescence     each  form  of  its  prisms ;  B,  separated  prisma. 


Vertical  section  of  the  Enamel  of  the  Human  Molar  Tooth. 


Fig.  78. 


286  OP   THE   PRIMARY   TISSUES    OF   THE   HUMAN   BODY. 

enamel-prism  is  originally  formed  (§  280).  In  a  perfect  state,  the  Enamel  con- 
tains but  an  extremely  minute  quantity  of  animal  matter;  but  if  a  young  tooth 
be  examined,  it  is  found  that,  after  the  calcareous  matter  of  the  tooth  has  been 
dissolved  away  by  an  acid,  there  remains  a  set  of  distinct  prismatic  cells,  which 
formed  (as  it  were)  the  moulds  in  which  the  mineral  substance  was  deposited.1 
The  Enamel,  when  once  formed,  appears  to  undergo  scarcely  any  further  change, 
and  it  possesses  no  power  of  self-regeneration  after  loss  of  substance  by  injury 
or  disease. 

277.  The  Cementum  or  Crusta  Petrosa  corresponds  in  all  essential  particulars 
with  Bone,  possessing  its  characteristic  lacunae,  and  being  also  traversed  by  vas- 
cular medullary  canals,  which  pass  into  it  from  its  external  surface,  wherever  it 
occurs  in  sufficient  thickness  (as  in  the  exterior  of  the  tooth  of  the  extinct 
Megatherium,  and  in  the  thick  plates  interposed  within  the  islets  of  Enamel  in 
the  teeth  of  Ruminants,  Rodents,  &c.) ;  in  Man,  however,  in  whose  teeth  the 
Cementum  is  very  thin,  such  vascular  canals  do  not  usually  exist,  though  Mr. 
Tomes  states  (Op.  cit.,  p.  57)  that  he  has  occasionally  met  with  them.     The 
Cementum  was  formerly  supposed  to  be  restricted  to  the  compound  teeth  of 
Herbivorous  animals  \  and  its  presence  in  the  simple  teeth  of  Man  and  the  Car- 
nivora  can  be  shown  only  by  the  application  of  the  Microscope.     In  the  latter 
it  forms  a  layer,  which  invests  the  fang,  and  which  decreases  in  thickness  as  it 
approaches  the  crown  of  the  tooth  (Fig.  73,  2, 7)  ;  at  the  time  of  the  first  emer- 
sion of  the  tooth,  it  covers  the  crown  also  with  a  very  thin  lamina,  which  is 
speedily  worn  away  by  use ;  on  the  other  hand,  its  thickness  around  the  apex 
of  the  fang  often  undergoes  a  subsequent  increase,  especially  when  chronic 
inflammation  and  thickening  take  place  in  the  membranous  contents  of  the 
socket  (d). 

278.  The  following  are  the  results  of  the  most  recent  Chemical  analyses  of 
the  component  structure  of  Human  Teeth : — a 

Incisors  of  Adult  Man. 

Dentine.  Enamel.  Cementum. 

Organic  matter        .    ••    .-        .         .         28.70  3.59  29.27 

Earthy  matter         .        .      ;.        .        71.30  96.41  70.73 


100.00  100.00          100.00 

The  proportion  of  these  two  components  varies  considerably  in  different  species ;  thus 
the  organic  basis  of  the  Elephant's  tusk  forms  as  much  as  43  per  cent,  of  the  whole.  It 
would  seem  even  to  vary  considerably  in  different  individuals  of  the  same  species ;  thus  in 
the  molar  teeth  of  one  man,  Von  Bibra  found  the  organic  matter  to  constitute  as  little  as 
21  per  cent,  whilst  in  another  it  was  28. — The  following  analyses  afford  a  more  particular 
view  of  the  components  of  each  substance: — 

Molars  of  Adult  Man. 

Dentine.  Enamel. 

Phosphate  of  Lime,  with  trace  of  fluate  of  lime  66.72  89.82 


Carbonate  of  Lime 
Phosphate  of  Magnesia 
Other  Salts 
Chondrin  (?) 


3.36  4.37 

1.08  1.34 

0.83  0.88 

27.61  3.39 


Fat  .....  0.40  0.20 


100.00          100.00 

1  The  Author  has  discovered  a  structure  precisely  resembling  this,  in  the  shells  of  many 
Mollusca.     See  "  Reports  of  the  British  Association"  for  1844  and  1847. 
3  See  Von  Bibra's  "Chemische  Untersuchungen  iiber  die  Knochen  und  Zahne." 


TEETH. DEVELOPMENT  OF  DENTINE 


287 


Incisors  of  Ox. 

Dentine. 
Phosphate  of  Lime,  with  trace  of)          gg  ^ 

fluate  of  lime        .  J 

Carbonate  of  Lime  7.00 

Phosphate  of  Magnesia  0.99 

Salts       ...  0.91 

Chondrin  (?)  .         .  30.71 

Fat  0.82 


100.00 


Enamel. 
81.86 

9.33 
1.20 
0.93 
6.66 
0.02 

100.00 


Cement. 
58.73 

7.22 
0.99 
0.82 
31.31 
0.93 

100.00 


Fig.  79. 


279.  The  Dentine  and  its  modifications,  the  Enamel,  and  the  Cementum,  origi- 
nate in  three  distinct  structures ;  which  may  be  termed  respectively,  the  dentinal- 
pulp,  the  enamel-pulp,  and  the  capsular  or  cemental-pulp ;  the  whole  forming 
the  "matrix"  from  which  the  entire  tooth  is  evolved. — The  Dentinal  pulp  is 
always  the  first-developed  part  of  the  matrix;  and  it  makes  its  appearance  in 
the  form  of  a  papilla,  budding  out  from  the  free  surface  of  a  fold  or  groove  of 
the  mucous  membrane  of  the  mouth.  The  substance  of  this  papilla  at  first  con- 
sists, according  to  Mr.  Tomes,1  of  a  very  delicate  areolar  tissue  composed  of 
delicate  fibres  and  bands,  whose  meshes  are  occupied  with  a  thick,  clear,  homo- 
geneous fluid  or  plasma,  scattered  through  which 
are  a  number  of  nucleated  cells ;  the  whole  being 
enclosed  in  a  dense,  structureless,  pellucid  mem- 
brane. The  papilla  is  copiously  supplied  with 
bloodvessels,  which  originate  in  a  trunk  that 
enters  its  base  (Fig.  79),  and  then  ramify  and 
spread  through  its  whole  substance,  at  last  form- 
ing a  capillary  network  which  terminates  in  loops 
near  its  apex.  These  vessels  are  accompanied 
by  nerves,  which  also  have  looped  terminations. 
— The  changes  in  which  the  conversion  of  the 
papilla  into  the  tooth-substance  consists,  com- 
mence near  the  coronal  surface;  where  the  cells 
of  the  pulp,  lying  beneath  its  investing  mem- 
brane, are  found  to  have  undergone  enlargement, 
and  to  be  thickly  scattered  at  pretty  regular  in- 
tervals through  a  sub-granular  uniting  medium, 
the  intermediate  areolar  tissue  having  now  dis- 
appeared (Fig.  80,  A)  ;  the  cavities  of  the  cells 
are  occupied  by  granular  matter.  The  blood- 
vessels now  begin  to  retreat  from  the  coronal 
surface  of  the  papilla,  so  that  few  are  seen  in  the 
part  which  exhibits  this  second  stage  of  develop- 
ment.— At  a  later  period,  the  cells  of  the  pulp 
exhibit  a  regular  linear  arrangement  (B),  their 
extremities  coming  into  close  approximation  with 
each  other;  and  the  intermediate  connecting 
substance  acquires  a  much  firmer  character.  Each  cell,  after  falling  into  line, 
undergoes  transverse  fission,  and  each  division  elongates  ;  so  that  in  this  manner 
their  extremities  are  brought  into  close  apposition.  Whilst  this  is  taking  place 
their  cavities  also  increase  in  length,  and  extend  to  the  extremities  of  the  cells ; 
and  at  last  the  intervening  septa  disappear,  so  that  the  cell-cavities  become  con- 
tinuous, and  constitute  tubes  (c).  At  the  same  time,  the  calcifying  process  is 
taking  place  in  the  intercellular  substance,  and  in  the  thick  walls  of  the  cells ; 


Vessels  of  DenM  Papilla. 


'Lectures  on  Dental  Physiology  and  Surgery,"  p.  84. 


288 


OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 


and  thus  the  dentine  with  its  tubuli  are  generated.  This  process  progressively 
extends  itself  from  the  surface  of  the  pulp,  towards  its  centre ;  for  as  the  more 
external  and  larger  cells  become  hardened,  the  inner  ones  increase  in  size,  assume 
the  linear  arrangement,  and  in  their  turn  become  converted  into  dentine;  until 
at  last  the  great  bulk  of  the  pulp  is  transformed,  leaving  only  a  comparatively 
small  portion,  which,  with  the  nerves  and  bloodvessels,  occupies  the  central 
cavity  of  the  tooth.  In  this  progressive  development,  it  often  happens  that  two 


Sections  of  the  Dentinal  Pulp  in  successive  stages  of  its  development. 

of  the  more  external  cells  unite  with  one  of  the  cells  next  to  them  on  the  internal 
side  (Fig.  80,  c),  their  two  canals  also  uniting  to  form  one ;  and  by  the  frequent 
repetition  of  this  process  of  union  it  happens,  that  the  number  of  dentinal  tubes 
gradually  diminishes  as  we  pass  from  the  periphery  towards  the  centre. — The 
"  nodular  layer"  (Fig.  76)  which  commonly  exists  near  the  surface  of  the  tooth- 
fang,  and  the  similar  structure  which  occasionally  (though  abnormally)  presents 
itself  elsewhere,  are  considered  by  Mr.  Tomes  to  depend  upon  the  partial  con- 
tinuance of  the  original  areolar  structure  of  the  pulp,  whilst  it  is  undergoing 
calcification ;  the  calcifying  process  having  either  commenced  at  an  unusually 
early  period,  when  as  yet  the  linear  arrangement  of  the  cells  for  the  development 
of  the  tubular  structure  has  not  yet  taken  place,  so  that  the  dentinal  substance 
thus  formed  has  a  very  imperfect  character ;  or,  in  other  cases,  the  space  origi- 
nally occupied  by  the  areolar  texture  not  having  been  filled  up,  whilst  the  cells 
were  undergoing  development  into  tubes,  so  that  vacuities  are  left,  which  pre- 
serve its  original  form.1 

280.  The  Enamel-pulp  is  not  formed  until  after  the  dental  papilla  has  become 
enclosed  in  a  capsule,  by  the  process  to  be  presently  described ;  and  it  is  derived 
from  the  free  inner  surface  of  the  capsule,  of  which  its  cells  may  be  considered 
as  the  epithelium.  Of  this  pulp,  however,  which  fills  the  whole  space  between 
the  surface  of  the  papilla  and  the  lining  of  the  follicle,  only  that  portion  which 
is  immediately  adjacent  to  the  former  is  the  actual  matrix  of  the  enamel;  the 
remainder  serves  but  a  temporary  purpose,  and  afterwards  disappears.  In  its 
earliest  condition,  the  enamel-pulp,  according  to  Mr.  Tomes,  bears  a  strong 
resemblance  to  the  first  stage  of  the  dentinal ;  for  it  consists  of  a  meshwork  of 
very  fine  fibres  (which  seem  to  be  composed  of  the  yellow  element),  whose  inter- 
spaces are  occupied  by  a  thick  transparent  fluid,  floating  in  which  are  some  pecu- 
liar nucleated  cells;  the  fluid,  however,  is  more  abundant,  and  the  cells  are 
fewer,  than  in  the  dentinal  pulp.  In  the  stratum  of  the  pulp  nearest  to  the 

1  In  the  above  sketch  of  the  history  of  the  development  of  the  Dentinal  pulp,  the  account 
given  by  Mr.  Tomes  has  been  followed,  as  that  which  the  Author's  own  observations  lead 
him  to  prefer  to  the  account  given  in  former  editions  on  the  authority  of  Prof.  Owen. — See 
also  the  "Beitriige  BUT  mikroskopischen  Anatomic  der  menschlichen  Ziihne,"  of  Dr.  J. 
Czermak. 


TEETH. DEVELOPMENT    OF   ENAMEL. 


289 


Fig.  81. 


surface  of  the  dentinal  papilla,  the  cells  multiply,  and  are  developed  into  the  form 
of  a  prismatic  epithelium  (Fig.  81,  j) ;  but  above  this,  the  cells  assume  the  stel- 
late form,  and  their  radiating  prolongations  coa- 
lesce, so  that  a  very  curious  tissue  is  formed,  which, 
though  not  uncommon  in  Plants  (as,  for  instance, 
in  the  Rush),  is  very  unusual  in  animals.1  In  the 
early  stage  of  its  development,  the  enamel-pulp  is 
traversed  throughout  by  bloodvessels,  which  are 
prolonged  into  it  from  the  inner  lining  of  the  cap- 
sule; but  these  gradually  retreat,  and  when  the 
calcification  of  the  enamel-matrix  is  going  on,  they 
have  entirely  withdrawn  themselves  from  the  pulp, 
the  membranous  lining  of  the  capsule,  however, 
being  itself  highly  vascular  and  somewhat  villous. 
One  purpose  of  the  stellate  tissue  would  seem  to 
be,  to  afford  a  space  for  the  columnar  tissue  and 
the  dentinal  pulp  to  extend  themselves  into  with- 
out resistance,  and  to  serve  as  a  protection  to  these 
structures  during  their  growth ;  but  it  may  also 
select  from  the  nutrient  materials  supplied  by  the 
blood,  those  which  the  cells  of  the  enamel-matrix 
require,  and  may  prepare  it  for  being  finally  appro- 
priated by  them.  These  cells  gradually  fill  them- 
selves with  calcareous  salts,  which  would  seem  to 
be  deposited  in  them  in  a  purely  crystalline  condi- 
tion, and  not  to  be  conjoined  (as  in  Bone  and  Den- 
tine) with  organic  matter;  for  the  small  proportion 
of  the  latter,  which  chemical  analysis  shows  to  exist 
in  Enamel  (§  27^),  is  probably  employed  wholly 
in  forming  the  walls  of  the  prismatic  cells,  which 
themselves  become  penetrated  by  the  consolidating 
substance.  That  so  large  a  proportion  of  the  calci- 
fying material  of  Enamel  consists  of  the  phosphate 
of  lime,  is  evidently  the  cause  of  its  extraordinary 
hardness  (§  76).  The  calcification  begins  on  the 
surface  of  the  dentinal  papilla,  which  is  excavated 
into  shallow  cups  that  receive  the  ends  of  the  ena- 
mel columns;  and  these  columnar  cells  are  at  first 
so  short,  as  to  constitute  but  a  very  thin  layer. 
As  calcification  takes  place  at  their  bases,  however, 
their  apices  lengthen;  and  this  either  by  the  for- 
mation, addition,  and  coalescence,  of  new  cells  fur- 
nished by  the  enamel-pulp,  or  else  by  the  subdivi- 
sion of  the  prismatic  cells  at  their  extremities  (just 
as  the  increase  in  length  of  a  Conferva  is  usually 
accomplished  by  the  repeated  fission  of  the  terminal  cell),  and  the  elongation  of 
the  new  cells  thus  formed,  the  process  being  continually  repeated.  In  either 
case,  it  seems  that  the  entire  length  of  each  enamel-prism  is  made  up  by  the 

1  This  curious  tissue  was  first  described  by  Messrs.  Todd  and  Bowman,  in  their  "Phy- 
siological Anatomy,"  p.  533,  Am.  Ed.  ;  these  authors,  however,  do  not  speak  of  it  as  com- 
posed of  stellate  cells,  but  describe  it  as  consisting  of  a  mesh  of  short  fibres,  meeting  in 
numberless  points,  at  each  of  which  a  transparent  clear  nucleus  is  visible.  The  Author 
agrees  with  Mr.  Tomes  in  the  interpretation  he  has  given  to  it ;  more  especially  since,  as 
Mr.  Tomes  remarks,  the  large  floating  cells  of  parts  of  the  pulp  in  which  this  tissue  does 
not  yet  exist,  present  indications  of  an  approach  towards  the  stellate  form. 

19 


Formation  of  Enamel:  h,  primary 
cells  suspended  in  fluid  blastema  g ; 
t,  the  same  more  fully  developed  and 
become  angular  ;j,  the  same  becoming 
prismatic;  k,  the  nucleus  disappear- 
ing; I,  the  modified  prismatic  cells, 
filled  with  calcareous  salts,  forming 
the  fibres  of  enamel. 


290 


OF   THE   PRIMARY   TISSUES   OP   THE   HUMAN   BODY. 


union  of  a  linear  series  of  cells  which  were  once  distinct,  their  cavities  having 
become  continuous ;  and  it  is  to  this  cause,  that  we  are  probably  to  attribute  the 
transverse  striae  with  which  they  are  marked  (§  276). * 

281.  The  Cemental  pulp  seems  to  be  a  substance  very  closely  resembling  that 
which  intervenes,  in  the  growing  bone,  between  its  surface  and  the  investing 

periosteum.  It  is  composed  of  nucleated  cells, 
Fig.  82.  scattered  through  a  granular  base,  lying  in  the 

areolse  of  a  fibrous  tissue;  and  this  tissue  is 
continuous  externally  with  that  of  the  dental  sac. 
According  to  Prof.  Owen  and  Mr.  Tomes,  the 
process  of  calcification,  which  begins  in  the  part 
nearest  the  dentine,  consists  in  the  absorption  of 
calcareous  matter  into  the  cavities  of  the  cells, 
in  the  more  close  aggregation  of  the  cells  with 
each  other,  and  in  the  changes  which  take  place 
coincidently  in  their  nuclei.  These,  which  are 
at  first  large  granular  spots  of  a  rounded  form, 
send  out  radiating  prolongations,  which  extend 
quite  to  the  borders  of  the  cell ;  and  as  the  calca- 
reous salts  which  penetrate  the  cell,  are  not  de- 
posited in  the  space  occupied  by  the  nuclei,  the 
stellate  cavities,  or  lacunae  and  diverging  canali- 
culi,  are  left,  which  are  so  analogous  to  those  of 
bone,  as  to  serve  to  identify  the  two  tissues.  In 
the  Cementum,  as  in  Bone  and  Dentine,  the  con- 
solidating substance  appears  to  consist  of  mineral 
and  organic  matter  in  a  state  of  chemical  union. 
The  boundaries  of  the  original  cells  disappear ; 
so  that  nothing  remains  in  the* fully-formed  ce- 
mentum,  to  mark  its  cellular  origin,  save  the 

stellate  lacunas  which  represent  the  positions  of  the  formerly  existing  nuclei. 

The  thin  layer  of  cementum,  which  is  affirmed  by  Mr.  Nasmyth  to  cover  the  crown 

of  the  newly-formed  tooth,  would  seem  to  be  formed  by  the  calcification  of  the 

tooth-capsule  itself.2 

282.  Having  thus  considered  the  mode  of  development  of  the  several  compo- 
nents of  the  Human  Teeth,  we  are  prepared  to  inquire  into  the  history  of 
evolution  of  each  tooth  as  a  whole,  and  into  the  successional  relations  of  the 
different  teeth  to  each  other.     This  topic  has  been  especially  elucidated  by  Prof. 
Groodsir,3  whose  account  will  be  here  followed. — At  the  6th  week  of  Fo3tal  life, 
a  deep  narrow  groove  may  be  perceived,  in  the  upper  jaw  of  the  Human  embryo, 
between  the  lip  and  the  rudimentary  palate ;  this  is  speedily  divided  into  two 
by  a  ridge,  which  afterwards  becomes  the  external  alveolar  process ;  and  it  is  in 
the  inner  groove,  that  the  germs  of  the  teeth  subsequently  appear.     Hence  this 
may  be  termed  the  primitive  dental  groove  (Fig.  83).     At  about  the  7th  week, 
an  ovoidal  papilla,  consisting  of  a  granular  substance,  makes  its  appearance  on  the 
floor  of  the  groove,  near  its  posterior  termination ;  this  papilla  is  the  germ  of 

1  A  precisely  similar  set  of  appearances  has  been  described  by  the  Author  in  the  prismatic 
cellular  structure  forming  the  shells  of  certain  Mollusks,  and  has  been  shown  by  him  to  be 
probably  due  to  the  same  cause — the  coalescence  of  flattened  epithelial  cells  in  vertical  piles. 
(See  the  "Reports  of  the  British  Association,"  1844,  1847.) 

2  For  an  account  of  Prof.  Owen's  researches  on  the  comparative  structtire  and  develop- 
ment of  the  Teeth  in  the  lower  Vertebrata,  see  his  "Odontography,"  and  his  Art.  Teeth  in 
the  "Cyclop,  of  Anat.  and  Physiol. ;"  also  "Princ.  of  Phys.,  Gen.  and  Comp.,"  \\  212- 
219,  322 /,  g,  324  o,  p,  and  326  o,  p,  q,  Am.  Ed. 

9  "Edinburgh  Medical  and  Surgical  Journal,"  vol.  li. 


Formation  of  the  Cementum :  m,  pri- 
mary cells ;  p,  their  granular  nuclei ;  n, 
more  minutely  granular  blastema;  o, 
the  primary  cell  enlarged,  and  receiving 
the  hardening  salts ;  nr,  calcified  blas- 
tema; p,  p>,  stellate  nuclei  of  fully- 
formed  cemental  cells. 


DEVELOPMENT   OP   THE   TEETH. 


291 


Fig.  83. 


the  anterior  superior  "milk"  Molar  tooth.  About  the  8th  week,  a  similar 
papilla,  which  is  the  germ  of  the  Canine  tooth,  arises  in  front  of  this  ;  and  during 
the  9th  week,  the  germs  of  the  Incisors  make  their  appearance  under  the  same 
form.  During  the  10th  week,  processes  from  the  sides  of  the  dental  groove, 
particularly  the  external  one,  approach  each  other, 
and  finally  meet  before  and  behind  the  papilla  of 
the  anterior  Molar;  so  as  to  inclose  it  in  a  follicle, 
through  the  mouth  of  which  it  may  be  seen.  By  a 
similar  process,  the  other  teeth  are  gradually  in- 
closed in  corresponding  follicles.  The  germ  of  the 
posterior  "  milk"  Molar  also  appears  during  the  10th 
week,  as  a  small  papilla.  By  the  13th  week,  the 
follicle  of  the  posterior  Molar  is  completed ;  and  the 
several  papilla  undergo  a  gradual  change  of  form. 
Instead  of  remaining,  as  hitherto,  simple,  rounded, 
blunt  masses  of  granular  matter,  each  of  them  as- 
sumes a  particular  shape ;  the  Incisors  acquire  in 
some  degree  the  flattened  form  of  the  future  teeth ;  the  Canines  become  simple 
cones  j-  and  the  Molars  become  cones  flattened  transversely,  somewhat  similar  to 
carnivorous  molars.  During  this  period,  the  papillae  grow  faster  than  the  folli- 
cles ;  so  that  the  former  protrude  from  the  mouth  of  the  latter.  At  this  time, 
the  mouths  of  the  follicles  undergo  a  change,  consisting  in  the  development  of 
their  edges,  so  as  to  form  opercula  ;  which  correspond  in  some  measure  with  the 
shape  of  the  crowns  of  the  future  teeth.  There  are  two  of  these  opercula  in  the 
Incisive  follicles,  three  for  the  Canines,  and  four  or  five  for  the  Molars.  At  the 
14th  week,  the  inner  lip  of  the  dental  groove  has  increased  so  much,  as  to  meet 
and  apply  itself  in  a  valvular  manner  to  the  outer  lip  or  ridge,  which  has  been 
also  increasing.  The  follicles  at  this  time  grow  faster  than  the  papillae,  so  that 

Fig.  84. 


Upper  jaw  of  Human  Embryo  at 
sixth  week ;  showing  b,  the  Primi- 
tive Denial  Groove,  behind  a,  the  Lip. 


Diagrams  illustrative  of  the  formation  of  a  Temporary,  and  its  corresponding  Permanent  Tooth 
from  a  Mucous  Membrane. 

the  latter  recede  into  the  former.  The  primitive  dental  groove  then  contains 
ten  papillae,  inclosed  in  as  many  follicles ;  and  thus  all  necessary  provision  is 
made  for  the  production  of  the  first  set  of  teeth.  (This  series  of  changes  is 
represented  in  Fig.  84,  a — //.)  The  groove  is  now  situated,  however,  on  a  higher 


292  OF   THE   PRIMARY   TISSUES    OF   THE   HUMAN   BODY. 

level  than  at  first;  and  it  has  undergone  such  a  change  by  the  closure  of  its 
edges,  as  to  entitle  it  to  the  distinctive  appellation  of  secondary  dental  groove. 
It  is  in  this  secondary  groove  that  those  structures  originate,  which  are  destined 
for  the  development  of  the  second  or  "  permanent''  set  of  Teeth — of  those  at 
least  which  replace  the  "  milk"  Teeth.  This  is  accomplished  in  the  following 
manner. 

283.  At  about  the  14th  or  15th  week,  a  little  crescentic  depression  may  be 
observed,  immediately  behind  the  inner  opercula  of  each  of  the  "  milk"  tooth- 
follicles.     This  depression  gradually  becomes  deeper,  and  constitutes  what  may 
be  termed  a  cavity  of  reserve ;  adapted  to  furnish  delicate  mucous  membrane, 
for  the  future  formation  of  the  sacs  and  pulps  of  the  ten  anterior  "permanent" 
teeth.    These  "cavities  of  reserve"  are  gradually  separated  from  the  "  secondary 
dental  groove,"  by-  the  adhesion  of  their  edges ;  and  they  thus  become  minute 
compressed  sacs,  situated  between  the  surface  of  the  gum  and  the  milk-sacs. 
They  gradually  recede,  however,  from  the  surface  of  the  gum,  so  as  to  be  pos- 
terior instead  of  anterior  to  the  milk-sacs ;  and  at  last  they  imbed  themselves  in 
the  submucous  cellular  tissue,  which  has  all  along  constituted  the  external  layer 
of  the  milk-sac.     The  implantation  of  the  "permanent"  tooth-sacs  in  the  walls 
of  the  temporary  follicles,  gives  to  the  former  the  appearance  of  being  produced 
by  a  gemmiparous  process  from  the  latter. — This  series  of  changes  is  represented 
in  Fig.  84,  g — n. 

284.  We  now  turn  to  the  "milk"  teeth,  the  papillae  of  which,  from  the  time 
that  their  follicles  close,  become  gradually  moulded  into  their  peculiarly  Human 
shape.     The  Molar  pulps  begin  to  be  perforated  by  three  canals,  which,  proceed- 
ing from  the  surface  towards  the  centre,  gradually  divide  their  primary  bases 
into  three  secondary  bases;  and  these  become  developed  into  the  fangs  of  the 
future  teeth.     Whilst  this  is  going  on,  the  sacs  grow  more  rapidly  than  the 
papillae,  so  that  there  is  an  intervening  space,  which  is  filled  with  a  gelatinous 
granular  substance — the  enamel-pulp;  this  closely  applies  itself  to  the  surface 
of  the  papilla,  but  does  not  adhere  to  it.     At  this  period,  the  tubercles  and 
apices  of  the  papillae  or  pulps  become  converted  into  dentine  or  tooth-substance, 
in  the  manner  already  stated  (§  279) ;  and  the  granular  matter  is  absorbed  as 
fast  as  this  appears;  so  that,  when  the  process  of  conversion  has  reached  the 
base  of  the  pulp,  the  interior  of  the  dental  sac  is  left  in  the  villous  and  vascular 
condition  of  a  true  Mucous  membrane,  having  upon  it  a  very  thin  layer  of  the 
prismatic  epithelium  which  constitutes  the  true  enamel  matrix  (§  280).     The 
opercula,  which  close  the  mouth  of  the  dental  sac,  attain  a  much  greater  develop- 
ment in  the  Molar  teeth  of  Herbivorous  animals ;  where  they  dip  down  into  the 
midst  of  the  dentinal  pulp,  and  give  origin  to  insulated  spots  both  of  enamel  and 
cementum.     It  has  been  remarked  by  Mr.  Lintott,  that  the  lines  along  which 
the  opercula  meet,  on  the  crown  of  the  Human  molar  teeth — that  is  to  say,  the 
groove  which  separates  their  tubercles — is  by  far  the  most  frequent  seat  of  inci- 
pient decay ;  probably  from  its  tissue  having  been  at  the  first  less  perfectly 
formed  than  that  of  the  remainder. 

285.  Whilst  these  changes  are  going  on,  other  important  preparations  are 
being  made  for  the  "  permanent"  set.     The  general  adhesion  of  the  edges  of 
the  "  primitive  dental  groove"  (§  282),  does  not  invade  the  portion,  which  is 
situated  behind  the  posterior  "  milk"  follicle ;  this  retains  its  original  appearance 
for  a  fortnight  or  three  weeks  longer,  and  affords  a  nidus  for  the  development 
of  the  papilla  and  follicle  of  the  anterior  "  permanent"  Molar  tooth,  which  is 
developed  in  all  respects  on  the  same  plan  with  the  "  milk"  teeth.     After  its 
follicle  has  closed,  the  edges  of  the  dental  groove  meet  over  its  mouth ;  but  as 
the  walls  of  the  groove  do  not  adhere,  a  considerably  cavity  is  left  between  the 
sac  of  the  tooth  and  the  surface  of  the  gum.     The  cavity  is  a  "reserve"  of  deli- 
cate mucous  membrane,  to  afford  materials  for  the  formation  of  the  second 


DEVELOPMENT   OF   THE   TEETH. 


293 


" permanent"  Molar,  and  of  the  third  "permanent"  Molar,  or  " wisdom-tooth." 
(The  process  just  described  is  represented  in  Fig.  85,  a — c.)  It  will  be  conve- 
nient here  to  continue  the  account  of  the  development  of  these  teeth,  although 
it  takes  place  at  a  much  later  period.  Towards  the  end  of  foetal  life,  the  increase 
of  the  bulk  of  the  "milk"  tooth-sacs  takes  place  so  much  more  rapidly  than  the 
growth  of  the  jaw,  that  the  sac  of  the  anterior  "  permanent"  Molar  is  forced 
backwards  and  upwards,  into  the  maxillary  tuberosity;  and  thus  it  not  only 
draws  the  surface  of  the  gum  in  the  same  direction,  but  lengthens  out  the  great 
"  cavity  of  reserve"  (Fig.  85,  d).  During  the  few  months  which  succeed  birth, 


00 


LJLJ 


Diagrams  illustrative  of  the  formation  of  the  three  Permanent  Molar  Teeth,  from  the  non-adherent 
portion  of  the  Dental  Groove. 

however,  the  jaw  is  greatly  lengthened;  and  when  the  infant  is  eight  or  nine 
months  old,  the  anterior  "permanent"  Molar  resumes  its  former  position  in  the 
posterior  part  of  the  dental  arch ;  and  the  great  "  cavity  of  reserve"  returns  to 
its  original  size  and  situation  (e).  This  cavity,  however,  soon  begins  to  bulge 
out  at  its  posterior  side,  and  projects  itself,  as  a  sac,  into  the  maxillary  tuberosity 
(/)  ;  a  papilla  or  pulp  appears  in  its  fundus;  and  a  process  of  contraction  sepa- 
rates this  portion  of  it  from  the  remainder.  Thus  the  formation  of  the  second 
"  permanent"  Molar  from  the  first,  takes  place  on  precisely  the  same  plan  with 
the  formation  of  the  "  permanent"  Bicuspids  from  the  temporary  Molars.  The 
new  sac  at  first  occupies  the  maxillary  tuberosity  (<?);  but  the  lengthening  of 
the  jaw  gradually  allows  it  to  fall  downwards  and  forwards,  into  the  same  line, 
and  on  a  level  with  the  rest  (Ti).  Before  it  leaves  the  tuberosity  altogether,  the 
posterior  extremity  of  the  remainder  of  the  "  cavity  of  reserve"  sends  backwards 
and  upwards  its  last  offset — the  sac  and  pulp  of  the  "  wisdom-tooth"  (i) ;  this 
speedily  occupies  the  tuberosity,  after  the  second  molar  has  left  it  (j) ;  and  ulti- 
mately, when  the  jaw  lengthens  for  the  last  time,  at  the  age  of  nineteen  or  twenty, 
it  takes  its  place  at  the  posterior  extremity  of  the  range  of  the  adult  teeth  (&). 
Thus,  the  "  wisdom-teeth"  are  the  second  products  of  the  posterior  or  great 
"  cavities  of  reserve;"  and  the  final  effects  of  development  in  the  "secondary 
dental  groove." 

286.  We  have  thus  sketched  the  history  of  the  Development  of  the  Teeth,  up 
to  the  time  when  they  prepare  to  make  their  way  through  the  gum.  The  first 
stage  of  this  development  may  be  termed  the  papillary ;  and  the  second  the 
follicular.  The  latter  terminates,  when  the  papillae  are  completely  hidden  by 
the  closure  of  the  mouths  of  the  follicles,  and  of  the  groove  itself.  The  succeed- 


294  OF   THE   PRIMARY   TISSUES    OF   THE   HUMAN  BODY. 

ing  stage,  which  has  long  been  known  as  the  saccular,  is  the  one  during  which 
the  whole  formation  of  the  Dentine,  and  of  the  Enamel,  takes  place.  It  is  during 
this  period,  also,  that  the  ossification  of  the  jaw  is  being  effected;  and  that  the 
bony  sockets  are  formed  for  the  teeth,  by  the  consolidation  of  the  anterior  and 
posterior  ridges  bounding  the  alveolar  groove  (in  which  the  dental  groove  was 
originally  imbedded),  and  of  the  interfollicular  septa,  which  are  produced  by  the 
meeting  of  transverse  projections  from  these  ridges.  We  have  now  only  to  con- 
sider the  fourth  or  eruptive  stage ;  that  in  which  the  Teeth  make  their  way 
through  the  gum.  This  process  chiefly  results  from  the  lengthening  of  the  fang, 
by  the  addition  of  new  dentinal  substance;  so  that  the  crown  of  the  tooth  is 
made  to  press  against  the  closed  mouth  of  the  sac  (Fig.  84,  m).  This  at  last 
gives  way,  and  the  sac  then  assumes  its  previous  condition  of  an  open  follicle. 
When  the  edge  of  the  tooth  has  once  made  its  way  through  the  gum,  it  advances 
more  rapidly  than  can  well  be  accounted  for  by  the  usual  rate  of  lengthening  of 
its  fang;  and  this  appears  to  be  due  to  the  separation  of  the  bottom  of  the  sac 
from  the  fundus  of  the  alveolus ;  so  that  the  whole  tooth  apparatus  is  carried 
nearer  to  the  surface,  leaving  a  space  at  the  bottom  of  the  alveolar  cavity,  in 
which  the  further  lengthening  of  the  root  can  take  place  (n).  The  open  portion 
of  the  sac  remains  as  the  narrow  portion  of  the  gum,  which  forms  a  vascular 
border  and  groove  round  the  neck  of  the  perfected  tooth  (o).  The  deeper  portion 
of  the  sac  adheres  to  the  fang  of  the  tooth ;  and  it  is  here  that  the  cemental  pulp 
is  found,  constituting  (as  it  were)  its  inner  layer.  What  is  commonly  denomi- 
nated the  periosteum  of  the  Tooth,  really  belongs  as  much  to  the  Alveolus.  It 
is  connected  with  the  tooth  by  the  submucous  cellular  tissue,  which  originally 
intervened  between  the  tooth-sac  and  the  walls  of  the  osseous  cavity. — During 
the  period  that  the  "milk"  teeth  have  been  advancing,  along  with  their  sockets, 
to  their  perfect  state  and  ultimate  position,  the  "  permanent"  sacs  have  been 
receding  in  an  opposite  direction,  and  have  with  their  bony  crypts  been  enlarg- 
ing; and  at  last  they  occupy  a  position  almost  exactly  below  the  former  (n  and 
o).  They  still  retain  a  communication  with  the  gum,  however;  the  channel  by 
which  they  descended  not  having  completely  closed  up,  and  the  neck  of  the  sac 
being  elongated  into  a  cord  which  passes  through  this.  The  channels  may  after- 
wards serve  as  the  itinera  dentium,  and  the  cords  as  gubernacula  ;  but  it  is 
uncertain  whether  they  really  afford  any  assistance  in  directing  the  future  rise 
of  the  tooth  to  the  surface ;  the  successive  stages  of  which  are  represented  in 
Fig.  84,  p — L  The  sacs  of  the  permanent  teeth  derive  their  first  vessels  from 
the  gums ;  ultimately  they  receive  their  proper  dental  vessels  from  the  milk-sacs ; 
and,  as  they  separate  from  the  latter  into  their  own  alveoli,  the  newly-formed 
vessels,  conjoining  into  common  trunks,  also  retire  into  permanent  dental  canals, 
and  gradually  become  the  most  direct  channels  for  the  blood  transmitted  through 
the  jaw. — The  history  of  development  in  the  Lower  Jaw  is  very  nearly  the  same ; 
the  chief  difference  being  in  the  origin  and  situation  of  the  primitive  dental 
groove. 

287.  The  following  interesting  generalizations  respecting  the  development  of 
the  teeth,  result  from  Prof.  Groodsir's  researches:  1.  The  "milk"  teeth  are 
formed  on  both  sides  of  either  jaw  in  three  divisions,  a  Molar,  a  Canine,  and  an 
Incisive;  in  each  of  which,  dentition  proceeds  in  an  independent  manner.  2. 
The  dentition  of  the  whole  arch  proceeds  from  behind  forwards;  the  Molar 
division  commencing  before  the  Canine,  and  the  Canine  before  the  Incisive.  3. 
The  dentition  of  each  of  the  divisions  proceeds  in  a  contrary  direction,  the  an- 
terior Molar  appearing  before  the  posterior,  the  central  Incisor  before  the  lateral. 
4.  Two  of  the  subordinate  phenomena  of  nutrition  also  follow  this  inverse  law ; 
the  follicles  closing  by  commencing  at  the  median  line  and  proceeding  backwards ; 
and  the  dental  groove  disappearing  in  the  same  direction.  5.  Dentition  com- 
mences in  the  upper  jaw,  and  continues  in  advance  during  the  most  important 


DEVELOPMENT  OF  THE  TEETH.  295 

period  of  its  progress.  The  development  of  the  superior  Incisors,  however,  is 
retarded  by  a  peculiar  cause;  so  that  the  inferior  incisors  have  the  priority  in 
the  time  of  their  completion  and  appearance.  6.  The  germs  of  the  "perma- 
nent" teeth,  with  the  exception  of  that  of  the  anterior  Molar,  appear  in  a  direc- 
tion from  the  median  line  backwards.  7.  The  "milk"  teeth  originate,  or  are 
developed,  from  mucous  membrane.  8.  The  "permanent"  teeth,  also  originat- 
ing from  mucous  membrane,  are  of  independent  origin,  and  have  no  connection 
with  the  "milk"  teeth.  9.  A  Tooth-pulp  and  its  sac  must  be  referred  to  the 
same  class  of  organs,  as  the  combined  papilla  and  follicle  from  which  a  Hair  or 
Feather  is  developed. 

288.  The  following  is  the  usual  order,  and  period  of  appearance,  of  the 
several  pairs  of  "milk"  teeth.     The  four  central  Incisors  first  present  them- 
selves, usually  about  the  7th  month  after  birth,  but  frequently  much  earlier  or 
later;  those  of  the  lower  jaw  appear  first.     The  lateral  Incisors  next  show  them- 
selves, those  of  the  lower  jaw  coming  through  before  those  of  the  upper;  they 
usually  make  their  appearance  between  the  7th  and  10th  months.     After  a  short 
interval,  the  anterior  Molars  present  themselves,  generally  soon  after  the  termi- 
nation of  the  12th  month ;  and  these  are  followed  by  the  Canines,  which  usually 
protrude  themselves  between  the  14th  and  20th  months.     The  posterior  Molars 
are  the  last,  and  the  most  uncertain  in  regard  to  their  time  of  appearance  ;  this 
varying  from  the  18th  to  the  36th  month.     In  regard  to  all  except  the  front 
teeth,  there  is  no  settled  rule  as  to  the  priority  of  appearance  of  those  in  the 
upper  or  under  jaw;  sometimes  one  precedes,  and  sometimes  the  other;  but  in 
general  it  may  be  stated,  that,  whenever  one  makes  its  appearance,  the  other  can- 
not be  far  off.     The  same  holds  good  in  regard  to  the  two  sides,  in  which  develop- 
ment does  not  always  proceed  exactly  pari  passu. — The  period  of  Dentition  is 
sometimes  one  of  considerable  risk  to  the  Infant's  life;    and  this  especially 
when  an  irritable  state  of  the  nervous  system  has  been  brought  about  by  unsuit- 
able food,  unwholesome  air,  or  some  other  cause  of  disordered  health.     In  such 
cases,  the  pressure  upon  the  nerves  of  the  gum,  which  necessarily  precedes  the 
opening  of  the  sac  and  the  eruption  of  the  tooth,  is  a  fruitful  source  of  irrita- 
tion; producing  disturbance  of  the  whole  system,  and  not  unfrequently  giving 
origin  to  fatal  Convulsive  affections.     These  last  have  been  particularly  studied 
by  Dr.  M.  Hall,  who  recommends  the  free  use  of  the  gum-lancet,  as  a  most 
important  means  of  prevention  and  cure;  but  the  Author  has  no  doubt  that 
too  much  attention  has  been  given  to  the  immediate  source  of  the  irritation, 
and  too  little  to  the  general  state  of  the  system ;  and  that  constitutional  treat- 
ment, especially  change  of  air  and  improvement  of  the  diet,  is  of  fundamental 
importance.     In  infants  whose  general  health  is  good,  and  who  are  not  over-fed, 
Dentition  is  a  source  of  but  very  trifling  general  disturbance ;  a  slight  febrile 
action,  lasting  but  for  a  day  or  two,  being  all  that  marks  the  passage  of  the 
tooth  through  the  capsule ;  and  its  eruption  through  the  gum  taking  place  with- 
out the  least  indication  of  suffering  or  disorder.     Any  existing  malady  or  abnor- 
mal tendency,  however,  is  pretty  sure  to  be  aggravated  during  the  "  cutting  of 
the  teeth;"  and  it  is,  therefore,  of  the  greatest  consequence  that  the  infant 
should  be  withdrawn,  during  this  period,  from  all  injurious  influences ;  and  that 
no  irregularity  of  diet,  or  deficiency  of  fresh  air  and  exercise,  should  operate 
to  its  disadvantage. 

289.  After  the  lapse  of  a  few  years,  the  further  elongation  of  the  jaw  per- 
mits the  appearance  of  the  first  true  Molar;  which,  as  already  remarked,  is 
really  a  "  milk"  tooth,  so  far  as  its  formation  is  concerned.     This  commonly 
presents  itself  about  the  middle  or  end  of  the  7th  year;  sometimes  preceding, 
and  sometimes  following,  the  exchange  of  the  central  Incisors,  which  takes 
place  about  the  same  time.     When  the  "permanent"  teeth  have  so  much  en- 
larged, that  they  can  no  longer  be  contained  within  their  own  alveoli,  they  press 


296  OF   THE   PRIMARY   TISSUES    OP    THE    HUMAN   BODY. 

upon  the  anterior  parietes  of  those  cavities,  and  cause  their  absorption;  so  that 
each  tooth  is  allowed  to  come  forwards,  in  some  degree,  into  the  lower  part  of  the 

socket  of  the  corresponding  "  temporary"  tooth. 
Fig.  86.  The  root  of  the  temporary  tooth  now  begins 

to  be  absorbed,  generally  at  the  part  nearest 
its  successor  (Fig.  86);  and  this  absorption 
proceeds  as  the  new  tooth  advances,  until  the 
root  of  the  "milk"  tooth  is  completely  re- 
moved; when  its  crown  falls  off,  leaving  room 
for  the  permanent  tooth  to  supply  its  place 
(Fig.  84,  p — t).  This  absorption  is  usually 
regarded  as  due  to  the  pressure  of  the  perma- 
nent tooth,  but  such  does  not  appear  to  be  the 
case ;  for  it  is  mentioned  by  Mr.  Bell,  that  it 
is  not  an  uncommon  occurrence  for  the  root  of 
the  temporary  tooth  to  be  wholly  absorbed,  and 
for  the  crown  to  fall  out  spontaneously,  long 

Section  of  portion  of  the  upper  jaw  of  a  ^fore  the  Succeeding  tooth  has  approached 
child,  showing  a  new  tooth  in  process  of  «•  Vacant  Space.  The  Same  has  been  re- 
formation, the  fang  of  the  corresponding  marked  by  Mr.  Bell,  of  the  cavity  in  the  jaw 
deciduous  tooth  being  absorbed.  which  is  formed  for  the  reception  of  the  sac 

of  the  "  permanent"  tooth,  at  the  time  that  it 

buds  off  from  that  of  the  "milk"  tooth;  the  excavation  being  often  seen  to  com- 
mence before  the  new  sac  is  formed.  Hence,  although  the  two  processes,  growth 
and  absorption,  are  usually  contemporaneous  in  each  instance,  they  are  by  no 
means  dependent  on  each  other.  Still,  it  would  seem  that  the  existence,  if  not 
the  pressure,  of  the  new  tooth  is  necessary  to  determine  the  absorption  of  the 
old;  for  cases  are  not  unfrequent,  in  which  the  temporary  teeth  retain  their 
situation  in  the  mouth,  with  considerable  firmness,  until  adult  age — the  corre- 
sponding permanent  ones  not  having  been  formed. 

290.  In  the  successive  replacement  of  the  "  milk"  teeth  by  the  "  permanent" 
set,  a  very  regular  order  is  usually  followed.  The  middle  incisors  are  first  shed 
and  renewed,  and  then  the  lateral  Incisors.  The  anterior  "  milk"  Molars  next 
follow;  and  these  are  replaced  by  the  anterior  Bicuspid  teeth.  About  a  year 
afterwards,  the  posterior  "  milk"  Molars  are  shed,  and  are  replaced  in  like  manner 
by  Bicuspid  teeth.  The  Canines  are  the  last  of  the  "milk"  teeth  to  be  ex- 
changed ;  the  development  of  the  new  ones  not  taking  place  until  the  12th  year. 
In  the  succeeding  year,  the  second  pair  of  the  true  Molars  appears ;  the  third 
pair,  or  denies  sapientiae,  are  seldom  developed  until  three  or  four  years  subse- 
quently, and  often  much  later. — It  has  been  proposed1  (and,  from  the  evidence 
adduced  in  its  favor,  the  proposition  would  seem  entitled  to  considerable  atten- 
tion) to  adopt  the  successive  stages  in  the  Second  Dentition,  as  standards  for 
estimating  the  physical  capabilities  of  Children,  especially  in  regard  to  those 
two  periods  which  the  Factory  Laws  render  it  of  the  greatest  importance  to 
determine,  namely,  the  ages  of  nine  and  thirteen  years.  Previously  to  the  former, 
a  Child  is  not  permitted  to  work  at  all;  and  up  to  the  latter,  it  may  be  only 
employed  during  nine  hours  a  day.  The  necessities  or  the  cupidity  of  Parents 
are  continually  inducing  them  to  misrepresent  the  ages  of  their  children ;  and 
it  has  been  found  desirable,  therefore,  to  seek  for  some  test,  by  which  the  capa- 
bility of  the  Child  may  be  determined,  without  a  knowledge  of  its  age.  A 
standard  of  Height  has  been  adopted  by  the  Legislature  for  this  purpose ;  but 
upon  grounds  which,  physiologically  considered,  are  very  erroneous ;  since,  as 

1  "  The  Teeth  a  Test  of  Age,  considered  with  reference  to  the  Factory  Children."  By 
Edwin  Saunders. 


DEVELOPMENT  OF  THE  TEETH.  297 

is  well  known,  the  tallest  children  are  frequently  the  weakliest.  According  to 
Mr.  Saunders,  the  degree  of  advance  of  the  Second  Dentition  may  be  regarded 
as  a  much  more  correct  standard  of  the  degree  of  general  development  of  the 
organic  frame,  and  of  its  physical  powers;  and  it  appears  from  his  inquiries,  that 
it  may  be  relied  on  as  a  guide  to  the  real  age,  in  a  large  proportion  of  cases; 
whilst  no  serious  or  injurious  mistake  can  ever  arise  from  its  use.  It  may  happen 
that  local  or  constitutional  causes  may  have  slightly  retarded  the  development 
of  the  Teeth ;  in  which  case  the  age  of  the  individual  would  rather  be  under- 
estimated, and  no  harm  could  ensue  :  on  the  other  hand,  instances  of  premature 
development  of  the  Teeth  very  rarely,  if  ever,  occur ;  so  that  there  is  no  danger 
of  imputing  to  a  Child  a  capability  for  exertion  which  he  does  not  possess,  as 
the  test  of  height  is  continually  doing.  Moreover,  if  such  an  advance  in  Denti- 
tion should  occur,  it  might  probably  be  regarded  as  indicative  of  a  corresponding 
advance  in  the  development  of  the  whole  organism ;  so  that  the  real  capability 
would  be  such  as  the  teeth  represent  it. 

291.  The  following  is  Mr.  Saunders' s  statement  of  the  Ages  at  which  the 
"  permanent"  Teeth  respectively  appear.  The  first  true  Molars  usually  make 
their  appearance  towards  the  end  of  the  7th  year.  Occasionally  one  of  them 
protrudes  from  the  gum  at  6,  or  more  frequently  at  6^  years  of  age;  but  the 
evolution  of  the  whole  of  them  may  be  regarded  as  an  almost  infallible  sign  of 
the  Child's  being  7  years  old.  In  other  instances,  where  the  tooth  on  one  side 
of  the  mouth  is  freely  developed,  it  is  fair  to  reckon  the  two  as  having  emerged 
from  their  capsule ;  since  the  development  of  the  other  must  be  considered  as 
retarded.  This  rule  only  holds  good,  however,  in  regard  to  teeth  in  the  same 
row ;  for  the  development  of  the  teeth  in  either  jaw  must  not  be  inferred,  from 
that  of  the  corresponding  teeth  in  the  other.  With  this  understanding,  the 
results  of  the  application  of  the  following  table  will  probably  be  very  near  the 
truth. 


Central  Incisors  developed  at 

Lateral  Incisors 

First  Bicuspid 

Second  Bicuspid 

Canines 

Second  Molars 


8  years. 

9  " 

10  " 

11  « 

12  to  12J 
12  £  to  14 


The  following  are  the  results  of  the  application  of  this  test,  in  a  large  number 
of  cases  examined  by  Mr.  Saunders.  Of  708  Children  of  nine  years  old,  530 
would  have  been  pronounced  by  it  to  be  near  the  completion  of  their  ninth  year ; 
having  the  central,  and  either  three  or  four  lateral,  incisors  fully  developed. 
Out  of  the  remaining  178,  it  would  have  indicated  that  126  were  8J  years  old, 
as  they  presented  one  or  two  of  the  lateral  Incisors ;  and  the  52  others  would 
have  been  pronounced  8  years  old,  all  having  three  or  four  of  the  central  Incisors. 
So  that  the  extreme  deviation  is  only  12  months  ;  and  this  in  the  inconsiderable 
proportion  (when  compared  with  the  results  obtained  by  other  means)  of  52  in 
708,  or  7i  per  cent.  Again,  out  of  338  children  of  13  years  of  age,  294  might 
have  been  pronounced  with  confidence  to  be  of  that  age,  having  the  Canines, 
Bicuspid,  and  second  Molars,  either  entirely  developed,  or  with  only  the  deficiency 
of  one  or  two  of  either  class.  Of  the  44  others,  36  would  have  been  considered 
as  in  their  13th  year,  having  one  of  the  posterior  Molars  developed ;  and  8  as 
near  the  completion  of  the  12th,  having  two  of  the  Canines,  and  one  or  two  of 
the  second  Bicuspid.  In  all  these  instances,  the  error  is  on  the  favorable  side 
— that  is,  on  the  side  on  which  it  is  calculated  to  prevent  injury  to  the  objects 
of  the  inquiry ;  in  no  instance  did  this  test  cause  a  Child  to  be  estimated  as  older 
or  more  fit  for  labor  than  it  really  was.1 

1  The  value  of  this  test,  as  compared  with  that  of  Height,  is  manifested  by  a  striking 
example  adduced  by  Mr.  Saunders.     The  height  of  one  lad,  J.  J.,  aged  8  years  and  4 


298  OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 


5.    Of  the  Simple  Tubular  Tissues  ; — Capillary  Bloodvessels  and 
Absorbents. 

292.  "We  have  seen  that  all  the  Animal  Tissues,  whose  structure  has  been 
yet  considered,  derive  the  materials  of  their  growth  and  renovation  from  the 
nutrient  fluid;  which  is  brought  into  a  more  or  less  close  relation  with  their 
elementary  parts,  by  means  of  Capillary  Bloodvessels.  These  seem  to  have  a 
claim  to  be  regarded  as  among  the  elementary  parts  of  the  fabric;  since  they  are 
formed  quite  independently  of  the  larger  trunks,  and  have  little  in  common  with 
them  in  their  function.  All  those  changes  which  take  place  between  the  blood 
and  the  surrounding  parts,  whether  ministering  to  the  operations  of  Nutrition, 
Secretion,  or  Respiration,  occur  during  its  movement  through  them;  and  the 
function  of  the  larger  trunks  is  merely  to  bring  to  them  a  constant  supply  of 

Fig.  87. 


Capillary  plexus  in  a  portion  of  the  web  of  &  Frog's  foot,  magnified  110  diameters:  1,  trunk  of  vein; 
2,  2,  2,  its  branches;  3,  3,  pigment-cells. 

fresh  blood,  regulated  according  to  the  demand  created  by  the  actions  to  which 
it  is  subservient,  and  to  remove  the  fluid  which  has  circulated  through  them. 
In  Man,  as  in  all  the  higher  Animals — in  the  adult  condition  at  least — the 
Capillary  circulation  is  entirely  carried  on  through  tubes  having  distinct  mem- 
months,  was  4  feet  and  £  of  an  inch ;  that  of  another  boy,  aged  8  years  and  7  months,  was 
only  3  feet  1\  inches.  According  to  the  standard  of  height  adopted  by  the  Factory  Com- 
missioners (namely  3  feet  10  inches),  the  taller  lad  would  have  been  judged  fit  for  labor, 
whilst  the  shorter  would  have  been  rejected.  The  Dentition  of  the  latter,  however,  was 
further  advanced  than  that  of  the  former;  for  he  had  two  of  the  lateral  Incisors,  whilst 
the  former  had  only  the  central ;  and  the  determination  of  their  relative  physical  powers, 
which  would  have  been  thus  formed,  would  have  been  in  complete  accordance  with  the 
truth.  The  elder  boy,  though  shorter  than  the  other  by  5  J  inches,  possessed  a  much  greater 
degree  both  of  corporeal  and  mental  energy,  and  his  pulse  was  strong  and  regular ;  whilst 
that  of  the  younger  lad,  who  was  evidently  growing  too  fast,  was  small  and  frequent. — An 
instance  even  more  striking  has  come  under  the  Author's  own  observation. 


STRUCTURE  AND  DEVELOPMENT  OF  CAPILLARY  BLOODVESSELS.     299 

branous  parietes.  These  tubes  commonly  form  a  minutely-anastomosing  network; 
into  which  the  blood  is  brought  by  the  ramifications  of  the  arteries  on  one  side, 
and  from  which  it  is  returned  by  the  radicles  of  the  veins  on  the  other.  The 
walls  of  the  tubes  are  composed  of  a  delicate  membrane,  in  which  an  appearance 
of  transverse  striation  (as  if  produced  by  minute  annular  fibres)  can  sometimes 
be  discerned.  The  diameter  of  the  Capillaries  varies  in  different  animals,  in 
accordance  with  that  of  their  blood-corpuscles;  thus  the  Capillaries  of  the  Frog 
are,  of  course,  much  larger  than  those  of  Man.  The  diameter  of  the  latter  ap- 
pears, from  the  measurements  of  Weber,  Miiller,  and  others,  to  vary  from  about 
the  l-3700th  to  the  l-2500th  of  an  inch;  but  as  they  can  only  be  examined  after 
death,  it  is  probable  that  these  statements  are  not  altogether  exact,  particularly 
as  tubes  of  the  smallest  of  the  above  sizes  would  not  admit  ordinary  blood-cor- 
puscles. The  dimensions  of  the  individual  vessels,  indeed,  are  by  no  means  con- 
stant ;  as  may  be  seen  by  watching  the  Circulation  in  any  transparent  part,  for 
some  little  time.  Putting  aside  the  general  changes  in  diameter,  which  result 
from  circumstances  affecting  all  the  capillaries  of  a  part,  it  may  be  observed  that 
a  single  capillary  will  sometimes  enlarge  or  contract  by  itself,  without  any  ob- 
vious cause.  Thus,  the  stream  of  blood  will  sometimes  be  seen  to  run  into 
passages,  which  were  not  before  perceived;  and  it  has  hence  been  supposed  that 
they  were  new  excavations,  formed  by  the  retreating  or  removal  of  the  solid  tis- 
sue through  which  its  passes.  But  a  more  attentive  examination  shows,  that 
such  passages  are  real  capillaries,  which  did  not,  at  the  time  of  the  first  obser- 
vation, admit  the  stream  of  blood-corpuscles,  in  consequence  of  the  contraction 
of  their  caliber,  or  of  some  other  local  impediment;  and  that  they  are  brought 
into  view  by  the  simple  increase  in  their  diameter.  The  compression  of  one  of 
the  small  arteries  will  generally  occasion  an  oscillation  of  the  corpuscles  of  blood 
in  the  smallest  capillaries,  which  will  be  followed  by  the  disappearance  of  some 
of  them;  but  when  the  obstruction  is  removed,  the  blood  soon  regains  its  pre- 
vious velocity  and  force,  and  flows  into  exactly  the  same  passages  as  before. 

293.  The  opinion  was  long  entertained,  that  there  are  vessels  adapted  to  sup- 
ply the  white  or  colorless  tissues;  carrying  from  the  arteries  the  " liquor  san- 
guinis,"  and  leaving  the  corpuscles  behind,  through  inability  to  receive  them. 
But  such  a  supposition  is  altogether  groundless.  Some  of  the  white  tissues,  as 
Cartilage,  are  altogether  destitute  of  vessels;  and  in  others,  the  supply  of  blood 
is  so  scanty,  as  not  to  communicate  to  them  any  decided  hue.  It  is  evident 
from  what  has  been  already  stated,  that  the  idea  that  Nutrition  can  only  be  car- 
ried on  by  means  of  Capillary  vessels,  is  entirely  gratuitous.  There  is  no  essen- 
tial difference,  in  fact,  between  the  nutrition  of  the  non-vascular  tissues,  and  that 
of  the  islets  in  the  midst  of  the  network  of  capillary  vessels  which  traverses  the 
most  vascular.  In  both  cases,  the  nutrient  materials  conveyed  by  the  blood  are 
absorbed  by  the  cells  or  other  elementary  parts  of  the  tissue  immediately  ad- 
joining the  vessels,  and  are  imparted  by  them  to  others  which  are  further  removed; 
and  the  only  difference  lies  in  the  amount  of  the  portion  of  tissue  which  has  to 
be  thus  traversed.  There  is  great  variety  in  this  respect,  as  we  have  seen, 
among  the  vascular  tissues ;  and  we  are  only  required  to  extend  our  ideas,  from 
the  largest  of  the  islets  which  we  find  in  these,  to  the  still  more  isolated  struc- 
tures of  which  the  non-vascular  tissues  are  composed.  The  distribution  of  Ca- 
pillaries through  the  vascular  tissues,  and  the  character  of  the  reticulation  which 
they  form,  vary  so  greatly  in  the  different  parts  of  the  fabric,  that  it  is  possible 
to  state  with  tolerable  certainty  the  nature  of  the  part  from  which  any  speci- 
men has  been  detached — whether  a  portion  of  skin,  mucous  membrane,  serous 
membrane,  muscle,  nerve,  fat,  areolar  tissue,  gland,  &c.  But  the  arrangement 
of  vessels  peculiar  to  each,  evidently  has  reference  only  to  the  convenience  of 
the  distribution  of  blood  among  the  elementary  parts  of  the  tissue,  and  varies 
with  their  form.  It  is  not  possible  to  imagine  that  it  has  any  other  relation  than 


300  OP   THE   PRIMARY   TISSUES   OF   THE   HUMAN    BODY. 

this  to  their  function;  since,  as  already  shown,  the  function  of  each  separate  ele- 
ment of  the  organ,  of  which  that  of  the  entire  organ  is  the  aggregate,  is  due  to 
its  own  inherent  vital  powers — the  supply  of  blood  being  only  required  as  fur- 
nishing the  material  on  which  these  are  to  be  exercised. 

294.  It  has  been  rendered  highly  probable,  by  the  observations  of  Schwann 
and  other  Histologists,  that  the  Capillaries  of  Animals  originate  in  cells,  like 
the  straight  and  anastomosing  Ducts  of  Plants.  Bodies  having  the  appearance 
of  cell-nuclei  may  frequently  be  seen  in  the  walls  of  the  capillaries  of  embryos 
and  of  tadpoles;  and  these  are  too  wide  apart  to  warrant  the  idea,  that  they  are 
the  nuclei  of  epithelial  cells,  such  as  those  which  line  the  larger  vessels.  Simi- 
lar nuclei  may  be  brought  into  view  in  the  capillaries  of  adult  animals,  by  treat- 
ing them  with  acetic  acid ;  and  they  are  particularly  well  seen  in  the  Pia  Mater, 
which  consists  almost  entirely  of  a  congeries  of  bloodvessels  (Fig.  88).  The 
accompanying  figure  shows  the  contrast  between  the  long  oval  nuclei  6,  6,  im- 
bedded at  intervals  in  the  walls  of  the  true  capillaries,  and  rather  projecting  on 
their  exterior;  and  the  nuclei  of  the  epithelium-cells,/,/,  lining  the  interior  of 

Fig.  88. 


Capillary  Bloodvessels  from  Pia  Mater:  a,  caliber  of  the  tube,  partly  occupied  by  oval  nuclei,  alternately 
arranged  lengthways,  and  epithelial  in  their  character ;  b,  b,  b,  nuclei  projecting  on  the  exterior  of  the  tube ; 
c,  c,  walls,  and  d,  caliber,  of  a  large  branch;/,/,  oval  nuclei,  arranged  transversely.  Magnified  410  di- 
ameters. 

a  larger  branch,  which  last  are  more  numerous  and  of  less  regular  form,  and  are 
sometimes  placed  transversely  to  the  direction  of  the  tube.  The  first  formation 
of  the  Capillary  bloodvessels  in  the  vascular  area  in  the  Bird's  egg,  seems  to  be 
effected  entirely  by  the  coalescence  of  cells,  which  send  off  prolongations  in 
various  directions,  in  the  manner  of  stellate  pigment-cells,  such  as  those  seen  at 
c,  c,  Fig.  87.  By  the  junction  of  these  prolongations,  a  network  of  tubes  is 
formed,  which  is  at  first  very  irregular  in  its  character;  the  greatest  diameter 
of  the  tubes  being  in  the  situation  of  the  centres  or  bodies  of  the  original  cells ; 
whilst  between  these,  at  the  points  where  their  prolongations  coalesced,  they  are 
much  contracted.  The  caliber  of  the  vessels,  however,  gradually  becomes 
equalized,  and  the  network  becomes  connected  with  the  larger  trunks,  and  bears 
a  part  in  the  general  circulation.  Appearances  indicative  of  a  similar  process 


DEVELOPMENT   OF   CAPILLARY   BLOODVESSELS. 


301 


Fig.  89. 


have  been  observed  by  Professor  Kblliker1  in  the  tail  of  the  very  young  Tad- 
pole, at  the  time  when  it  is  undergoing  rapid  increase.  The  first  lateral  vessels 
of  the  tail  have  the  form  of  simple  arches,  passing  between  the  main  artery 
and  vein,  and  are  produced  by  the  junction  of  prolongations  shot  forth  from 
these  vessels,  with  similar  prolongations  from  stellate  or  caudate  cells  in  the 
substance  of  the  tail  (Fig.  89).  Some  of  the  latter  again,  coalesce  with  those 
of  other  cells ;  so  that  an  irregular  network  is  produced,  which  communicates 
with  the  previously-formed  trunks.  The  cavities  of  these  cells  and  of  their 
radiations  (which  are  at  first  so  fine  as  to  be  almost  impervious),  having  coalesced, 
they  begin  to  receive  fluid  from  the 
vessels,  then  enlarge,  and  finally  ap- 
pear as  continuations  of  them.  The 
observations  of  Messrs.  Paget  and 
Kirkes3  on  the  development  of  blood- 
vessels in  the  fine  gelatinous  tissue 
conveying  the  umbilical  vessels  of  the 
embryo-sheep  to  the  uterine  cotyle- 
dons, lead  to  a  very  similar  idea  of  the 
process;  for  here,  also,  there  may  be 
seen  chains  and  networks  of  cells  of 
various  shapes,  some  fusiform,  some 
stellate,  some  round  or  oval  with  thread- 
like prolongations,  connected  to  each 
other  and  to  the  adjacent  bloodvessels 
by  very  slender  prolongations,  which 
gradually  enlarge,  and  become  filled 
with  blood  from  the  vessels  with  which 
they  come  into  communication.  Some 
of  the  appearances  noticed  by  these 
observers,  however,  indicate  that  blood- 
corpuscles  may  be  formed  in  parts  of 
this  network  which  have  not  yet  come 
into  connection  with  the  neighboring 
vessels,  and  from  other  materials  than 
those  directly  derived  from  their  con- 
tents; for  colored  nucleated  blood- 
corpuscles  were  observed  in  distended 
parts  of  the  narrowest  tubes,  which 
were  connected  at  either  extremity, 
either  with  bloodvessels,  or  with  other 
elongated  cells,  by  filamentous  pro- 
longations far  too  fine  to  transmit  par- 
ticles of  the  size  of  blood-corpuscles. 
295.  Some  observations  have  been 
recently  adduced  by  Dr.  W.  T.  Gaird- 
ner,3  which  indicate  that  this  inde- 
pendent formation  of  bloodvessels  and 
of  blood  may  take  place  (as  John  Hun- 
ter maintained,  and  as  many  others 
have  since  asserted,  though  without  adequate  evidence),  to  a  yet  greater  extent. 
The  case  was  one  in  which  a  false  membrane  had  been  formed,  within  the  arach- 

1  "  Annales  des  Sciences  Naturelles,"  Zool.  Aout,  1846. 

2  "Supplement  to  Professor  Muller's  Elements  of  Physiology,"  pp.  104,  105. 

3  "Edinburgh  Monthly  Journal,"  October  1851,  pp.  392-4. 


Formation  of  Capillaries  in  tail  of  Tadpole :  a,  a, 
capillaries  permeable  to  blood ;  6,  6,  fat  granules  at- 
tached to  the  walls  of  the  vessels,  and  concealing  the 
nuclei;  c,  hollow  prolongation  of  a  capillary  ending 
in  a  point ;  d,  a  branching  cell,  with  nucleus  and  fat- 
granules,  communicating  by  three  branches  with  ca- 
pillaries already  formed;  e,  blood-corpuscles,  still  con- 
taining granules  of  fat. 


302  OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 

noid  cavity,  apparently  by  the  organization  of  a  clot  of  blood  that  had  been 
effused  in  consequence  of  injury;  and  it  exhibited  a  large  varicose  blood-channel, 
which  had  no  very  definite  wall,  with  a  great  number  of  smaller  branching  ves- 
sels, having  very  distinct  parietes.  The  blood  of  the  large  channel  presented 
blood-corpuscles  of  all  dimensions,  from  the  smallest  appreciable  size  to  that  of 
the  fully -formed  disk;  those  of  the  inferior  or  intermediate  sizes  being  decidedly 
more  numerous  than  in  ordinary  blood.  Combining  these  two  facts,  therefore, 
the  relatively  low  state  of  development  of  the  largest  channel,  and  the  young 
condition  of  the  blood  which  it  contained,  there  scarcely  appears  room  for  doubt 
that  the  whole  plexus  was  of  independent  origin,  and  was  not  derived  from  the 
adjacent  bloodvessels.  On  the  other  hand,  it  seems  at  least  equally  certain  that 
in  the  production  of  new  parts  for  the  repair  of  injuries,  the  tissue  ordinarily 
becomes  supplied  with  bloodvessels,  not  by  any  such  independent  formation  in 
its  own  substance,  but  by  mere  out-growth  from  the  capillaries  of  the  subjacent 
structure.  "The  vessel,"  according  to  the  description  of  Mr.  Paget,1  "  will  first 
present  a  slight  dilatation  in  one,  and  coincidently,  or  shortly  after,  in  another 
point;  as  if  its  wall  yielded  a  little  near  the  edge  or  surface.  The  slight  pouches 
thus  formed  gradually  extend,  as  fluid  canals  or  diverticula,  from  the  original 
vessel;  still  directing  their  course  towards  the  edge  or  surface  of  the  new  mate- 
rial, and  crowded  with  corpuscles,  which  are  pushed  into  them  from  the  main 
stream.  Still  extending,  they  converge;  they  meet;  the  partition-wall,  that  is 
at  first  formed  by  the  meeting  of  their  closed  ends,  clears  away,  and  a  perfect 
arched  tube  is  formed ;  through  which  the  blood,  diverging  from  the  main  or 
former  stream,  and  then  rejoining  it,  may  be  continuously  propelled/7  Some- 
times the  projecting  pouch  in  which  the  new  vessel  originates,  gives  way,  and 
the  blood-corpuscles  escape  into  the  substance  of  the  parenchyma ;  at  first  they 
lie  there  in  a  confused  cluster;  but  before  long  they  manifest  a  definite  direction, 
and  the  cluster  bends  towards  the  line  in  which  the  new  vessel  might  have 
formed,  and  thus  opens  into  the  other  portion  of  the  arch,  or  into  some  adjacent 
vessel.3  This  formation  of  new  passages  in  a  determinate  direction,  by  a  pro- 
cess of  "  channelling,"  indicates  the  existence  of  forces  in  the  parenchyma 
itself,  that  determine  the  direction  in  which  the  vessels  shall  prolong  themselves, 
when  the  new  passage  is  formed  by  their  outgrowth ;  in  fact,  it  would  not  seem 
improbable  that  this  outgrowth  is  itself  but  a  sort  of  varicose  dilatation,  conse- 
quent upon  the  breaking-down  of  the  tissue  into  which  it  extends  itself.  And 
it  is  conformable  to  this  view,  that,  according  to  the  observations  of  Mr.  Travers,3 
when  a  new  capillary  arch  is  formed  by  outgrowth,  it  does  not  at  once  convey 
a  stream  of  blood;  but  isolated  corpuscles  enter  it,  and  perform  an  oscillating 
movement  for  some  hours,  before  any  series  of  them  passes  into  it ;  so  that  we 
cannot  regard  the  new  canal  as  formed  by  the  vis  d  tergo  of  the  circulating 
blood,  as  some  have  maintained  it  to  be. 

296.  The  structure  of  the  minutest  Absorbent  vessels  is  very  similar  to  that 
of  the  capillary  Bloodvessels.  Both  in  the  substance  of  the  tissues  in  which  the 
lymphatics  take  their  origin,  and  in  the  extremities  of  the  intestinal  villi  in  which 
are  the  radicles  of  the  lacteals,  they  seem  to  originate  in  plexuses ;  which,  however, 
are  unlike  those  of  the  capillary  bloodvessels,  in  communicating  with  trunks  on 
one  side  only.  These  plexuses  are  formed,  according  to  the  observations  of  Prof. 
Kblliker  (loc.  cit.),  on  the  same  original  plan  with  those  of  the  bloodvessels; 
namely,  by  the  junction  and  fusion  of  processes  from  stellate  cells,  either  with 
each  other,  or  with  offshoots  from  previously-existing  vessels.  In  the  develop- 
ment of  the  lymphatic  tubuli,  however,  the  union  of  the  cells  is  in  a  more  simple 


1  "Lectures  on  Repair  and  Reproduction,"  in  "Med.  Gaz."  July  13,  1849,  p. 

2  Paget,  Op.  cit.,  p.  72. 

8  "Physiology  of  Inflammation  and  the  Healing  Process,"  p.  77. 


71. 


STRUCTURE   OF   MUSCULAR   TISSUE.  303 

linear  direction,  than  it  is  in  the  production  of  capillaries ;  the  anastomoses  of 
the/ormer,  in  their  complete  state,  being  much  more  rare  than  that  of  the  latter. 

6.    Of  the  Muscular  Tissue. 

297.  The  Muscular  tissue,  which  is  the  instrument  of  the  performance  of  all 
the  sensible  movements  of  the  body,  exists  under  two  forms; — the  ultimate  fibres 
being  marked  in  one  by  transverse  and  longitudinal  striae  ; — whilst  in  the  other 
they  are  plain,  smooth,  or  unstriped.    The  former  is  chiefly  concerned  in  the 
various  movements  which  are  effected  through  the  agency  of  the  Nervous  system, 
and  which  are  connected  with  the  peculiarly  Animal  powers  of  the  being.     The 
latter  is  with  difficulty  called  into  action  through  the  nervous  system,  but  is 
much  more  readily  excited  by  stimuli  applied  to  itself;  and  this  is  employed  to 
perform  various  movements,  which  are  more  immediately  concerned  in  the  Yfege- 
tative  or  Organic  functions. — By  some,  the  two  forms  of  tissue  have  been  spoken 
of  as  those  of  "  voluntary"  and  of  "involuntary"  muscle :  but  this  distinction  is 
not  correct ;  since  every  muscle  ordinarily  termed  voluntary  may  be  called  into 
action  involuntarily,  and  the  Heart,  which  is  a  purely  "  involuntary"  muscle, 
has  the  striated  fibre  characteristic  of  the  "  voluntary." 

298.  When  we  examine  an  ordinary  Muscle  (from  one  of  the  extremities,  for 
example,)  with  the  naked  eye,  we  observe  that  it  presents  a  fibrous  appearance ; 
and  that  the  fibres  are  arranged  with  great  regularity,  in  the  direction  in  which 
the  muscle  is  to  act.    Upon  further  examination  it  is  found,  that  these  fibres  are 
arranged  in  fasciculi  or  bundles  of  larger  or  smaller  size,  connected  by  means  of 
areolar  tissue ;  and  when  the  Microscope  is  applied  to  the  smallest  fibre  which 
can  be  seen  with  the  naked  eye,  it  is  seen  itself  to  consist  of  a  fasciculus,  com- 
posed of  a  number  of  cylindrical  fibres  lying  in  a  parallel  direction,  and  closely 
bound  together.     These  primitive  fibres  present  two  sets  of  markings  or  stride  ; 
one  set  longitudinal,  the  other  transverse  or  annular.     By  more  closely  ex- 
amining these  fibres  when  separated  from  each  other,  it  is  frequently  seen  that 
each  may  be  resolved  into  fibrittae,  by  the 

splitting  of  its  contents  in   a  longitudinal  Fig-  90. 

direction,  as  shown  in  Fig.  90.     These  fibril- 

Ise  have  a  peculiar  beaded  appearance,  which 

will  be  presently  noticed  more  particularly. 

— It  not  unfrequently   happens,   however, 

that  when  a  fibre  is  drawn  apart,  its  contents 

separate  in  the  direction  of  the  transverse 

striae ;  forming  a  series  of  disks,  as  shown  in 

Fig.  91.     This  cleavage  is  just  as  natural  as 

the  former,  though  less  frequent ;  and  it  leads 

.    7       Vj3  \  .  ,»  T»/T          i  Fasciculus  of  Striated  Muscular  Fibres ;  the 

US  tO  a  View  Of  the  Composition  Of  MuSCUlar      fibresseparatedatoneendintobrush-likebun- 

Fibre,  somewhat  different  from  the  one  com-    dies  offibrma;. 
monly  adopted.     To  use  the  words  of  Mr. 

Bowman,1  it  would  be  as  proper  to  say  "that  the  fibre  is  a  pile  of  disks,  as  that 
it  is  a  bundle  of  jibrillae  ;  but  in  fact  it  is  neither  the  one  nor  the  other,  but  a  mass 
in  whose  structure  there  is  an  intimation  of  the  existence  of  both,  and  a  tendency 
to  cleave  in  the  two  directions.  If  there  were  a  general  disintegration  along  all 
the  lines  in  both  directions,  there  would  result  a  series  of  particles,  which  may  be 
termed  primitive  particles  or  sarcous  elements,  the  union  of  which  constitutes  the 
mass  of  the  fibre.  These  elementary  particles  are  arranged  and  united  together 
in  the  two  directions.  All  the  resulting  disks,  as  well  as  fibrillae,  are  equal  to 

1  "On  the  Minute  Structure  and  Movements  of  Voluntary  Muscle,"  in  "Philosophical 
Transaction,"  1840. 


304 


OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 


one  another  in  size ;  and  contain  an  equal  number  of  particles.  The  same  par- 
ticles compose  both.  To  detach  an  entire  fibrilla,  is  to  abstract  a  particle  of 
every  disk ;  and  vice  versd." 

Fig.  91. 


Fig.  92. 


Muscular  Fibre  broken  across,  showing  the  un 
torn  Mydemma  connecting  the  fragments. 


Portion  of  Striated  Muscular  Fibre  separating  into  disks,  by  cleavage  in  direction  of  Transverse  striae. 

299.  The  elements  of  Muscular  Fibre  are  bound  together,  in  the  perfect  con- 
dition of  the  fibre,  by  a  very  delicate  tubular  sheath.     This  cannot  always  be 
readily  brought  into  view ;  but  it  is  occasionally  seen  with  great  distinctness :  thus, 
when  the  two  ends  of  the  fibre  are  drawn  apart,  its  contents  will  sometimes 
separate  without  the  rupture  of  the  sheath,  which  then  becomes  evident  (Fig.  92) ; 
and  this,  during  the  act  of  contraction,  may  sometimes  be  observed  to  rise  up  in 

wrinkles  upon  the  surface  of  the  fibre,  as 
seen  in  Fig.  96.  This  sheath  is  quite 
distinct  from  the  areolar  tissue,  which 
binds  the  fibres  into  fasciculi ;  and  it  has 
been  termed,  for  the  sake  of  distinction, 
the  Myolemma.  Its  existence  may  be 
demonstrated  in  any  Muscular  fibre,  by 
subjecting  it  to  the  action  of  fluids  which 
occasion  a  swelling  of  its  contents ;  this 
is  especially  the  effect  of  acids  and  alkalies,  and  may  be  well  produced  by  the 
citric  and  tartaric  acids,  and  by  potash.  For  a  time,  the  Myolemma  yields  to 
the  distension  which  takes  place  from  within ;  but  at  last  it  bursts  at  particular 
points,  and  a  sort  of  hernia  of  its  contents  takes  place,  making  the  existence  of 
a  perfect  envelop  in  all  other  parts  quite  evident.  This  membrane  is  itself 
perfectly  transparent,  and  has  nothing  to  do  with  the  production  of  either  the 
longitudinal  or  the  transverse  striae.  There  is  no  reason  to  believe  that  it  is 
perforated  either  by  nerves  or  by  capillary  vessels ;  in  fact,  it  seems  to  be  an 
effectual  barrier  between  the  real  elements  of  Muscular  structure,  and  the  sur- 
rounding parts.  That  it  has  no  share  in  the  contraction  of  the  fibre,  is  evident 
from  the  fact  just  mentioned,  respecting  the  condition  which  it  occasionally  pre- 
sents when  the  fibre  is  much  shortened. 

300.  Muscular  Fibres  are  commonly  described  as  cylindrical;  but  there  is 
reason  to  believe  that  they  are  rather  of  a  polygonal  form,  their  sides  being 
flattened  against  those  of  adjoining  fibres  (Fig.  93).     In  some  instances  the  angles 
are  sharp  and  decided;  in  others  they  are  rounded  off,  so  as  to  leave  spaces  be- 
tween the  contiguous  fibres  for  the  passage  of  vessels.     The  average  diameter  of 
the  fibres  in  Man  is  stated  by  Mr.  Bowman  (loc.  cit.)  at  about  l-400th  of  an 
inch ;  being  about  l-352d  of  an  inch  in  the  male,  and  l-454th  of  an  inch  in 
the  female.     He  has  met  with  extremes,  however,  as  wide  apart  as  l-507th  and 
l-192d  of  an  inch  in  the  male  ;  and  1-61 5th  and  l-384th  of  an  inch  in  the 
female.     The  average  distance  between  the  strise  is  about  l-9400th  of  an  inch; 
but  it  is  sometimes  only  l-15,000th,  and  sometimes  as  much  as  l-6000th,  vary- 


STRUCTURE   OF   MUSCULAR   TISSUE. 


305 


ing  with  the  state  of  contraction  or  relaxation  of  the  fibre.1 — It  has  been  main- 
tained by  some  that  each  Muscular  fibre  is  a  hollow  bundle  of  fibrillae ;  but  the 
appearance  presented  by  transverse  sections  proves  that  this  is  not  the  case,  the 
whole  area  of  the  tube  being  occupied  by  fibrillae,  without  any  trace  of  central 

Fig.  93. 


Fig.  94. 


Transverse  section  of  Muscular  Fibres,  from  pectoral  muscle  of  Teal ;  showing  the  irregular  form  of  the 
fibres,  and  the  aggregation  of  circular  particles,  with  which  they  are  completely  filled. 

cavity.  The  extremities  of  the  cut  fibrillae,  however,  cannot  always  be  distin- 
guished in  Mammalia,  in  consequence,  as  it  would  seem,  of  their  close  and  inti- 
mate lateral  union ;  but  they  are  very  evident  in  Birds,  Reptiles,  and  Fishes 
(Fig.  93).  The  addition  of  an  acid  increases  the  distinctness  of  the  fibrillae,  by 
widening  the  interstices  between  them. 

301.  When  the  fibrillae  are  separately  examined,  they  are  found  to  present 
an  alternation  of  dark  and  light  spaces,  corresponding  with  the  transverse  striae 
of  the  fibre,  and  the  lighter  intervals  between  them. 
It  is  this  alternation  which  gives  to  the  fibrillae  the 
beaded  appearance  thej*present,  when  their  outline 
is  not  perfectly  seen  (Fig.  94).  When  well-prepared 
specimens,  however,  are  carefully  examined  under  a 
sufficient  magnifying  and  good  defining  power,  it  is 
seen  that  the  border  of  the  fibrillae  is  straight  or  nearly 
so;  the  beaded  appearance  being  an  optical  illusion. 
Moreover,  each  of  the  light  spaces  is  seen  to  be  crossed 
by  a  delicate  but  distinct  line  ;  separating  it  into  two 
equal  parts ',  and  upon  attentive  examination  it  is  seen 
that  a  transparent  border,  equal  in  breadth  to  either  of  these  parts,  exists  at 
the  sides,  as  well  as  between  the  ends,  of  the  dark  spaces  (Fig.  95).  Thus  each 
dark  space  is  completely  surrounded  by  this  pellucid  border;  and  it  can  scarcely 
be  doubted  that  the  whole  constitutes  a  complete  though  minute  cell,  and  that 
the  entire  fibrilla  is  made  up  of  a  linear  aggregation  of  such  cells.3  When  the 

1  It  is  curious  that  whilst  the  diameter  of  the  fibres  varies  considerably  in  different 
animals,  being  generally  much  greater  in  the  cold-blooded  than  in  the  warm-blooded  tribes 
(corresponding  with  the  larger  size  of  the  blood-disks  of  the  former),  the  diameter  of  the 
fibrillce,  and  the  distance  of  the  striae  from  each  other,  vary  extremely  little. 

2  This  account  of  the  ultimate  structure  of  Muscular  Fibre  was  first  published  simul- 
taneously (March,  1846),  by  the  Author  of  this  Treatise,  in  his  "Elements  of  Physiology," 

20 


Fragment  of  Muscular  Fibre 
from  macerated  heart  of  Ox, 
showing  formation  of  strife  by 
the  aggregation  of  fibrillae. 


306 


OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 


Structure  of  the 
ultimate  fibrillai  of 
Striated  Muscular 
Fibre:  a,  a  fibril 
in  a  state  of  ordina- 
ry relaxation ;  6,  a 
fibril  in  a  state  of 
partial  contraction. 


Fig.  95.  fibril  is  in  a  state  of  relaxation,  as  seen  at  a,  the  diameter  of  the 

cells  is  greatest  in  the  longitudinal  direction ;  but  when  it  is 
contracted,  the  fibril  increases  in  diameter  as  it  diminishes  in 
length :  so  that  the  transverse  diameter  of  each  cell  equals  or 
even  exceeds  the  longitudinal  diameter,  as  seen  at  b.  The  dif- 
ference between  the  two  states  is  frequently  much  more 
striking  than  is  represented  in  the  figure. — Thus  the  act  of 
Muscular  contraction  seems  to  consist  in  a  change  of  form  in 
the  cells  of  the  ultimate  fibrillse,  which  must  be  regarded  as  a 
manifestation  of  forces  in  their  interior,  that  have  been  deve- 
loped in  previous  acts  of  Nutrition  (§  110) ;  and  it  thus  corre- 
sponds very  closely  with  the  contraction  of  certain  Vegetable 
tissues,  of  which  the  component  cells  change  their  form  when 
irritated,  and  thus  produce  a  movement.1  The  essential  differ- 
ence, therefore,  between  the  striated  muscular  tissue  of  Ani- 
mals, and  the  contractile  tissues  of  Plants,  consists  in  the  sub- 
jection of  the  former  to  Nervous  influence. — The  diameter  of 
the  ultimate  fibrillse,  and  the  length  of  the  component  cells, 
will  of  course  vary  according  to  the  contracted  or  relaxed  con- 
dition of  the  fibre ;  but  they  otherwise  seem  to  be  tolerably 
uniform  in  different  animals.  The  average  diameter  may  be 
stated  at  about  l-10,000th  of  an  inch;  but  it  has  been  observed 
as  high  as  l-5000th,  and  as  low  as  l-20,000th,  even  when  not 
put  upon  the  stretch.  The  length  of  the  component  cells  cor- 
responds, of  course,  to  the  distance  of  the  strise  on  the  entire 
fibre ;  and  this  also  has  been  just  shown  to  average  about 
l-10,000th  of  an  inch. 
302.  The  general  opinion  as  to  the  disposition  of  the  fibres  during  the  con- 
traction of  Muscle,  was  for  a  long  period  that  of  Prevost  and  Dumas,  who  stated 
that  they  were  thrown  into  a  sinuous  or  zigzag  flexure.  More  recent  observa- 
tions, however,  have  fully  demonstrated  the  incorrectness  of  this  view;  the 
improbability  of  which  might  have  been  suspected  from  the  consideration  that 
fibres  in  this  state  of  flexure  could  scarcely  be  imagined  to  be  exerting  any  force 
of  traction.  Prof.  Owen  has  noticed  that,  in  the  contracted  state  of  the  very 
transparent  muscles  of  some  Entozoa,  each  separate  fibre,  which  may  be  seen 
with  great  distinctness,  presents  a  knot  or  swelling  in  the  middle,  besides  being 


Am.  Ed.,  and  by  Dr.  Sharpey,  in  his  new  edition  of  Dr.  Quain's  "Elements  of  Anatomy." 
Both  of  these  statements,  which  were  completely  independent  of  each  other,  were  founded 
upon  the  examination  of  the  very  beautiful  preparations  of  Muscular  Fibre,  made  by  Mr. 
Lealand  the  Optician ;  who  appears  to  have  been  the  first  to  direct  attention  to  the  transverse 
line  dividing  the  bright  space,  and  to  the  bright  border  edging  the  dark  spot.  A  similar 
delineation  had  previously  been  published,  however,  by  Dr.  Goodfellow  ("Physiological 
Journal,"  No.  iv.) ;  but  his  interpretation  of  the  appearances  was  altogether  different; 
for  he  considered  the  dark  spaces  as  the  "  sarcous  elements"  of  Mr.  Bowman,  and  re- 
garded them  as  separately  inclosed  within  partitions  formed  by  internal  prolongations  of 
the  general  investing  Myolemma.  By  Mr.  Erasmus  Wilson,  again,  the  appearances  were 
described  as  leading  to  the  belief  that  two  kinds  of  cells  exist  in  each  fibrilla,  a  dark 
and  a  light ;  a  pair  of  light  cells,  separated  by  the  delicate  transverse  line  just  spoken  of, 
being  interposed- between  each  pair  of  dark  ones  ("System  of  Human  Anat.,  4th  Am.  Ed., 
p.  171).  The  bright  edging  to  the  dark  spots  was  overlooked  by  him. — The  view  taken 
by  Dr.  Sharpey  and  the  Author  has  the  entire  concurrence  of  several  of  the  most  emi- 
nent Microscopists  in  London  and  elsewhere  (see,  for  example,  Mr.  Quekett's  "Practical 
Treatise  on  the  Use  of  the  Microscope,"  2d  edit.,  pi.  ix.,  fig.  12) ;  and  testimony  in 
its  favor  has  been  given  by  some,  who,  before  they  saw  the  preparations  which  afford 
the  evidence  of  its  truth,  had  entirely  discredited  it.  (See  Dr.  Hassall's  "Microscopic 
Anatomy,"  pp.  341,  548.) 

1  See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  \  138,  and  CHAP,  xix.,  Am.  Ed. 


STRUCTURE   OF   MUSCULAR   TISSUE.  307 

generally  thickened ;  but  that  it  is  simply  shortened,  without  falling  out  of  the 
straight  line.  Dr.  Allen  Thomson  remarked  the  same  thing  in  the  Frog; 
single  fibres,  whilst  continuing  in  contraction,  being  simply  shortened,  without 
falling  into  zigzag  lines :  and  he  was  led  to  suspect,  from  this  and  other  cir- 
cumstances, that  the  zigzag  arrangement  was  not  produced,  until  the  act  of 
contraction  had  ceased.  The  inquiries  of  Mr.  Bowman  (loc.  cit.)  have  proved 
most  satisfactorily,  that,  in  the  state  of  contraction,  there  is  an  approximation 
of  the  transverse  striae,  and  a  general  shortening  of  the  fibre ;  and  that  its 
diameter  is  at  the  same  time  increased ;  but  that  it  is  never  thrown  out  of  the 
straight  line,  except  when  it  has  ceased  to  contract,  and  its  two  extremities  are 
still  held  in  proximity  by  the  contraction  of  other  fibres.  The  whole  process 
may  be  distinctly  seen  under  the  Microscope,  in  a  single  fibre  isolated  from  the 
rest :  it  is,  of  course,  desirable  to  select  the  specimen  from  those  animals,  in 
which  the  contractility  of  the  Muscle  is  retained  for  the  longest  period  after 
death — which  is  particularly  the  case  in  Reptiles  among  Yertebrata,  and  in 
most  Invertebrata  (Mr.  Bowman  particularly  recommends  the  Crab  and  Lob- 
ster) ;  but  the  change  has  been  fully  proved  to  differ,  in  no  essential  degree,  in 
the  warm-blooded  Vertebrata.  The  contraction  usually  commences  at  the  ex- 
tremities of  the  fibre ;  but  it  frequently  occurs  also  at  one  or  more  intermediate 
points.  The  first  appearance  is  a  spot  more  opaque  than  the  rest,  caused  by 
the  approximation  of  a  few  of  the  dark  points  of  some  of  the  fibrillae  :  this  spot 
usually  extends  in  a  short  time  through  the  whole  diameter  of  the  fibre ;  and 
the  shading,  caused  by  the  approximation  of  the  transverse  striae,  increases  in 
intensity.  The  striae  are  found  to  be  two,  three,  or  even  four  times  as  numerous, 
in  the  contracted  as  in  the  uncontracted  part ;  and  are  also  proportionally  nar- 
rower and  more  delicate.  The  line  of  demarcation  between  the  contracted  and 
uncontracted  portions  is  well  defined ;  but,  as  the  process  goes  on,  fresh  striae 
are  absorbed  (as  it  were)  from  the  latter  into  the  former.  The  contracted  part 
augments  in  thickness;  but  not  in  a  degree  commensurate  with  its  diminished 
length ;  so  that  its  solid  parts  lie  in  smaller  compass  than  before — the  fluid 
which  previously  intervened  between  them  being  pressed  out  in  bullae  under  the 
myolemma  (Fig.  96).  The  force  with  which  the  elements  of  the  fibre  thus  tend 
to  approximate,  is  evidently  considerable ;  for  if  the  two  extremities  be  held 
apart,  the  fibre  is  not  unfrequently  ruptured.  This  corresponds  with  the  ap- 
pearances found  in  the  muscles  of  persons  who  have  died  from  tetanus;  for  in 
the  ruptured  fibres  of  those  muscles,  which  have  been  the  subjects  of  the  spas- 
modic action,  the  striae  have  been  observed  to  approximate  so  closely  as  to  be 

Fig.  96. 


Muscular  fibre  of  Dytiscus,  showing  the  contracted  state  in  the  centre ;  the  striae  approximated ;  the  breadth 
of  the  fibre  increased ;  and  the  myolemma  raised  in  bullae  on  its  surface. 

scarcely  distinguishable.  When  the  contraction  is  not  very  decided,  the  dark 
and  elevated  spots  appears  to  play  like  a  wave  along  the  fibre,  before  it  in- 
volves the  whole  diameter  in  any  part  (Fig.  97,  B);  and  even  when  consider- 
able traction  is  being  exercised,  there  is  continual  interchange  in  the  elements 
by  which  it  is  effected — the  disks  at  one  end  of  the  contracted  part  receding 
from  each  other,  whilst  at  the  other  end  new  disks  are  being  received  into  it. 
303.  The  foregoing  description  is  chiefly  derived  from  the  appearances  pre- 


308 


OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 


sented  by  Muscular  Fibre,  when  spontaneously  passing  into  that  state  of  contrac- 
tion' which  is  termed  the  rigor  mortis  (§  333)  ;  but  there  can  be  no  reasonable 


Fig.  97. 


I 


Muscular  Fibre  of  Skate,  in  a  state  of  rest  (A),  and  in  three  different  stages  of  contraction  (B,  c,  D). 

doubt,  that  the  phenomena  of  contraction,  excited  by  the  agency  of  the  nerves, 
are  precisely  similar.  Mr.  Bowman  has  remarked,  that  stimuli  of  various 
kinds,  directly  applied  to  them,  produce  corresponding  effects,  although,  in  the 
case  of  galvanism,  the  change  is  too  rapid  for  its  steps  to  be  followed ;  and  that, 
from  the  appearances  presented  by  muscles  which  have  been  affected  with  tetanic 
spasms,  the  contraction  produced  by  nervous  agency  may  be  inferred  to  cor- 
respond in  character. — The  zigzag  arrangement  which  is  so  often  seen  in  the 
fibres,  may  be  easily  produced,  by  approximating  the  ends  of  a  fasciculus,  after 
the  irritability  of  its  fibres  has  ceased;1  and  seems  to  be  that  into  which  fibres 
are  naturally  thrown,  if,  on  elongation  following  contraction,  they  are  not  at 
once  stretched  by  antagonist  muscles.  Many  facts  support  the  opinion,  that, 
when  an  entire  muscle  is  contracting,  all  its  fasciculi  are  not  in  contraction  at 
once ;  but  that  there  is  a  continual  interchange  in  the  parts  by  which  the  ten- 
sion is  effected,  some  relaxing  whilst  others  are  shortening.  On  examining  a 
muscle  of  which  some  fasciculi  present  the  zigzag  arrangement,  others  will  be 
seen  (if  the  two  extremities  have  not  been  purposely  approximated)  to  be  quite 
straight,  and  in  a  state  of  contraction ;  and  the  former  appearance  seems  to  be 
presented  by  bundles  of  fibres,  which  have  either  not  yet  entered  into  contrac- 
tion, or  which  have  relaxed  after  undergoing  it,  but  of  which  the  extremities 
are  still  approximated  by  the  agency  of  other  contracting  fibres.  Again,  the 
sound  emitted  by  a  muscle  in  vigorous  contraction,  indicates  a  continual  move- 
ment among  its  particles  (§  330).  And  the  great  excess  of  force  put  forth, 
when  from  any  cause  an  unusual  amount  of  nervous  power  is  determined  to  a 
muscle  (as  in  violent  passion  or  mania,  or  in  those  peculiar  states  of  abstraction 
in  which  the  attention  can  be  entirely  concentrated  upon  any  one  part),  above 
that  which  an  ordinary  voluntary  effort  can  evoke,  clearly  indicates  that,  in  the 
latter  case,  only  a  part  of  the  muscle  can  be  in  action  at  once,  which  seems  to  be 
attributable  to  this  constant  movement  of  its  substance. — The  result  of  various 
experiments  made  for  the  purpose,  leads  to  the  conclusion,  that  the  total  bulk 
of  a  muscle  in  contraction  is  not  less  than  when  it  is  in  a  relaxed  state ;  or  that 
the  difference,  if  any  exist,  is  extremely  trifling. 

304.  Every  Muscular  Fibre,  of  the  striated  kind  at  least,  is  attached  at  its 
extremities  to  white  fibrous  tissue;  through  the  medium  of  which  it  exerts  its 
contractile  power  on  the  bone  or  other  substance  which  it  is  destined  to  move. 
The  whole  fasciculus  of  fibrillse  sometimes  ends  abruptly  in  a  perfect  disk;  but 
not  unfrequently  the  extremities  of  the  fibres  become  rounded  or  conical,  in  con- 

1  Mr.  Bowman's  conclusions  have  been  since  confirmed  by  Prof.  E.  Weber  ("Archives 
d' Anatomic  Gdnerale,"  Jan.  1846),  and  by  other  observers. 


STRUCTURE   OF   MUSCULAR   TISSUE. 


309 


sequence  of  the  prolongation  of  certain  fibrillae  beyond  others.  Prof.  Kb'lliker 
describes  the  terminal  fibrillae  as  occasionally  losing  their  transverse  striae,  and 
as  passing  with  apparent  continuity  into  the  fibrils  of  the  tendon,  the  myolemma 
not  being  continued  over  the  extremity  of  the  fibres;  but  it  has  always  appeared 
to  the  Author,  that  the  connection  between  the  muscle  and  the  tendon  is  esta- 
blished rather  through  the  medium  of  the  myoleinma  than  through  that  of  the 
fibrillae.  Where  the  muscular  fibre  terminates  in  a  broad  flat  disk  (Fig.  98), 


Attachment,  of  Tendon  to  Muscular  Fibre,  in  Skate. 

the  tendinous  fibres  appear  at  first  to  stop  short  upon  its  surface ;  but  a  more 
careful  examination  will  generally  enable  them  to  be  traced  over  the  myolemma 
of  the  cylindrical  portion  of  the  fibre;  and  the  Author  has  occasionally  seen  in- 
dications of  a  double  spiral  arrangement  of  these  fibres  around  the  sheath  of  the 
muscular  fibre,  which  has  also  been  described  by  Dr.  Leidy.  When  the  fibres 
of  a  muscle  are  inserted  more  or  less  obliquely  into  the  side  of  a  tendon  whose 
fibres  take  a  different  direction,  the  muscular  fibres  are  attached  by  rounded  or 
blunt  conical  ends  to  the  side  of  the  tendinous  fasciculi,  which  are  excavated 
into  little  shallow  pits  or  dimples  to  receive  them ;  and  the  continuity  of  the 
myolemma  over  their  extremities  can  then  then  be 
distinctly  made  out.  FiS-  "• 

305.  The  plain,  smooth,  or  non-striated  form  of 
Muscular  tissue,  ordinarily  presents  itself  in  the  con- 
dition of  flattened  bands,  whose  diameter  is  usually 
between  l-2000th  and  l-3000th  of  an  inch;  their 
substance  is  translucent,  but  sometimes  finely  granu- 
lar; and  they  are  usually  marked  at  intervals  by 
peculiar  elongated  nuclei,  which,  when  not  originally 
visible,  may  be  rendered  so  by  acetic  acid  (Fig.  99). 
These  bands  are  generally  collected  into  fasciculi,  in 
which  they  lie  parallel  with  one  another;  but  the 
fasciculi  themselves  often  cross  each  other  and  inter- 
lace. They  have  not,  as  a  general  rule,  fixed  points 
of  attachment,  like  those  of  the  muscles  composed 
of  striated  fibres ;  but  form  continuous  investments 
around  cavities  lined  by  mucous  or  other  membranes, 
as  the  alimentary  canal,  the  uterus,  the  bladder,  the 
vascular  trunks,  &c. ;  or  are  dispersed  through  the 
substance  of  other  fibrous  tissues,  especially  the  skin, 
to  which  they  impart  a  contractile  property. — This 
tissue,  however,  has  lately  been  resolved  by  Prof. 
Kb'lliker1  into  a  yet  more  elementary  form ;  for  he 


Non-striated  Muscular  Fibre;  at 
&,  in  its  natural  state ;  at  a,  showing 
the  nuclei  after  the  action  of  acetic 
acid. 


Kolliker  and  Siebold's  Zeitschrift,"  1849. 


310 


OF  THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 


Fig.  100. 


has  shown  that  every  so-called  fibre  is  either  a  single  elongated  cell,  or  is  a  fas- 
ciculus of  such  cells;  each  cell  having  an  elongated  staff-like  nucleus,  which 
is  one  of  its  most  distinctive  characters.  Three  principal  forms  of  such  cells 
are  described  by  him:  1.  Short,  rounded,  fusiform,  or  nearly  rectangular 
plates,  like  those  of  epithelium,  about  l-1125th  of  an  inch  long,  and  l-1875th 
of  an  inch  broad:  2.  Long  plates  of  irregular  rectangular,  fusiform,  or  club 
shape,  with  fringed  edges,  about  l-562d  of  an  inch  long,  and  1-3  750th  of  an 
inch  broad  :  3.  Long,  narrow,  fusiform,  round,  or  flattened  fibres,  with  pointed 
terminations  (Fig.  100),  which  are  either  straight  or  wavy,  from  about  1 -612th 
to  l-50th  of  an  inch  long,  and  from  1-562 5th  to  1-1 12 5th  of  an  inch  in  breadth. 
The  first  and  second  of  these  forms  are  only  found  in  the  walls  of  the  blood- 
vessels; and  the  first  may  be  easily  mistaken  for  the 
cells  of  epithelium ;  the  last  form  is  the  one  which 
presents  itself  everywhere  else.  These  muscular 
fibre-cells  are  composed  of  a  soft  yellow  substance, 
which  swells  in  water  and  acetic  acid,  in  which  last 
it  becomes  of  a  paler  color.  There  is  no  appreciable 
difference  between  the  outer  and  inner  parts ;  though 
when  treated  with  acetic  acid  it  would  seem  as  if 
each  fibre-cell  had  a  delicate  covering.  Their  sub- 
stance is  homogeneous,  with  faint  longitudinal  stria- 
tions;  and  they  often  contain  small,  pale  granules, 
sometimes  yellow  globules  of  fatty  matter.  Each 
fibre-cell  has  a  pale  nucleus  (sometimes  only  percep- 
tible when  it  is  treated  with  acetic  acid,  6),  which 
constitutes  its  most  distinctive  character.  Its  form 
is  peculiar,  being  like  a  staff  rounded  at  each  end 
(c);  its  substance  is  homogeneous;  its  length  from 
l-2800th  to  l-1875th  of  an  inch;  and  its  breadth 
from  about  l-25,000th  to  l-14,000th  of  an  inch.— 
The  muscles  composed  of  this  form  of  tissue  may  be 
divided  (according  to  Prof.  Kolliker)  into  (A)  the 
pure  smooth  muscles,  which  contain  no  other  kind 
of  tissue,  such  as  those  of  the  nipple,  the  corium, 
the  interior  of  the  eye,  the  intestinal  canal,  the  blad- 
der, the  prostate,  the  vagina,  the  smaller  arteries, 
veins,  and  lymphatics;  and  (B),  the  mixed  smooth 
muscles,  which  contain,  besides  the  muscular  fibre- 
cells,  areolar  tissue,  and  elastic  fibres;  such  are  the 
trabeculae  of  the  spleen  and  corpora  cavernosa,  the 
dartos,  the  circular  fibres  of  the  larger  arteries  and 
veins,  the  long  and  transverse  fibres  of  the  urethra,  prostatic  duct,  Fallopian 
tubes,  and  uterus;  and  in  the  trachea,  bronchi,  urethra,  inner  muscular  layer 
of  the  testicles,  seminal  ducts,  &c.,  they  change  by  imperceptible  degrees  into 
the  first  form. 

306.  The  muscular  structure  of  the  Heart  is  peculiar,  in  presenting  the  gene- 
ral arrangement  of  the  non- striated  muscles,  as  regards  the  interlacement  of  the 
fasciculi  and  the  absence  of  fixed  points  of  attachment,  with  the  ultimate  struc- 
ture of  the  striated.  The  fibres  are  of  smaller  diameter,  however,  than  those  of 
the  voluntary  muscles ;  and  the  striae  are  less  strongly  marked,  and  are  less 
regular.  In  -the  heart,  too,  is  seen  more  frequently  than  elsewhere,  the  subdi- 
vision and  anastomosis  of  the  muscular  fibres;  which,  first  observed  by  Prof. 
Kolliker  (in  1849)  in  the  heart  of  the  frog,  has  been  witnessed  by  the  same  dis- 
tinguished anatomist  in  the  cardiac  fibres  of  Man  and  of  various  among  the 
higher  animals. — No  proper  gradation  can  be  anywhere  traced  from  the  striated 


Fusiform  cells  of  Smooth  Muscular 
Fibre,  from  the  renal  vein  of  Man ; 
a,  two  cells  in  their  natural  state, 
one  of  them  showing  the  staff- 
shaped  nucleus;  b,  a  cell  treated 
with  acetic  acid,  with  its  nucleus  c 
brought  strongly  into  view. 


STRUCTURE   OF   MUSCULAR   TISSUE.  311 

to  the  non-striated  form;  but  the  two  sometimes  come  into  very  close  apposition, 
as  where  the  constrictors  of  the  pharynx  overlie  the  muscular  coat  of  the  oaso- 
phagus  itself.1 

307.  The  Chemical  Composition  of  Muscular  Fibre  seems  to  be  very' uniform, 
from  whatever  source  it  is  obtained.  It  is  impossible,  however,  to  determine  it 
with  precision ;  on  account  of  the  difficulty  of  completely  isolating  the  substance 
of  the  fibres  from  the  areolar  tissue,  vessels,  and  nerves,  that  are  blended  with 
them.  The  proper  muscular  substance  differs  from  the  simple  fibrous  tissues, 
in  not  being  resolvable  into  gelatin  by  the  prolonged  action  of  boiling  water ; 
and  in  being  soluble  in  acetic  acid,  from  which  it  is  precipitated  by  ferrocyanide 
of  potassium,  showing  that  it  belongs  to  the  proteine-compounds.  It  is  not, 
however,  true  Fibrin,  but  corresponds  rather  to  coagulated  Albumen  (§§  21, 
25).  The  following  analysis  of  Muscle  by  Berzelius  corresponds  very  exactly 
with  those  since  made  by  Braconnet,  Schultz,  Marchand,  and  other  chemists  : — 


Proper  Muscular  substance     .       . ., ; . 

Gelatin  (from  areolar  tissues)          .   . 

Albumen  and  haematin   . 

Phosphate  of  lime,  with  albumen 

Alcoholic  extract,  with  salts  (lactates  ?) 

Watery  extract,  with  salts 

Water,  and  loss      .... 


15.80 
1.90 
2.20 
.08 
1.80 
1.05 

77.17 

100.00 


Thus  something  less  than  23  per.  cent  of  solid  matter  exists  in  ordinary  meat; 
and  in  100  parts  of  this  solid  matter,  there  are  about  3?  parts  of  fixed  salts. — 
The  close  correspondence  in  ultimate  composition,  between  dried  Muscle,  and 
dried  Blood,  according  to  the  analyses  of  Playfair  and  Bb'ckmann,  is  not  a  little 
remarkable.  The  following  are  their  results  : — 

PLAYFAIR.  BOCKMANN. 

Muscle.  Blood.  Muscle.  Blood. 

Carbon  51.83  51.95  51.89  51.96 


Hydrogen 
Nitrogen 
Oxygen 
Ashes 


7.57  7.17  7.59  7.33 

15.01  15.07  15.05  15.08 

21.36  21.39  21.24  21.21 

4.23  4.42  4.23  4.42 


The  nature  of  the  saline  constituents  of  Muscle,  however,  indicates  its  relation 
to  be  rather  with  the  contents  of  the  Corpuscles,  than  with  the  Blood  as  a  whole 
(§  140);  for  the  percentage  composition  of  the  entire  Ash  is — chloride  of  po- 
tassium 14.8,  phosphoric  acid  36.6,  sulphuric  acid  2.9,  potash  40.2,  and  earths 
with  oxide  of  iron  5.6. — Some  very  interesting  researches  have  been  made  by 
Helmholtz,2  on  the  chemical  changes  induced  in  the  tissue  by  Muscular  action. 
Powerful  contractions  were  induced  by  electricity  in  the  amputated  leg  of  a  Frog, 
and  were  kept  up  as  long  as  the  irritability  was  retained :  the  flesh  of  the  two 
limbs  was  then  analyzed;  and  it  was  found  that,  in  every  instance,  the  water- 
extractive  was  diminished  in  the  electrized  muscle,  to  the  extent  of  from  20  to 
24  per  cent.,  whilst  the  alcoholic  extract  was  increased  to  about  the  same  amount. 
Similar  results  were  obtained  from  experiments  on  warm-blooded  animals ;  the 
amount  of  change,  however,  being  less,  on  account  of  the  shorter  duration  of 
their  muscular  irritability.  It  may  be  expected  that  more  exact  analyses  will 

1  The  distinctness  of  the  two  kinds  of  tissue  is  curiously  marked  in  the  case  of  the 
parasitic  Trichina  spiralis,  which  infests  the  striated-fibre  muscles  alone,  and  may  be  seen 
to  stop  short  at  the  margin  of  the  inferior  constrictor,  without  passing  on  to  the  tissue 
beneath. 

2  "Miiller's  Archiv.,"  1845. 


312  OF   THE   PRIMARY  TISSUES   OF   THE    HUMAN   BODY. 

unequivocally  indicate  the  production  of  an  augmented  amount  of  those  products, 
which  we  know  to  result  from  the  retrograde  metamorphosis  of  the  muscular 
substance,  consequent  upon  its  functional  activity  (§§  52-62). 

308.  Muscular  tissue,  properly  so  called,  is  as  extra- vascular  as  cartilage  or 
dentine ;  for  its  fibres  are  not  penetrated  by  vessels ;  and  the  nutriment  required 
for  the  growth  of  its  contained  matter  must  be  drawn  by  absorption  through 
the  myolemma.     But  the  substance  of  Muscle,  as  a  whole,  is  extremely  vascu- 
lar, the  Capillary  vessels  being  distributed  in 

Fig.  101.  parallel  lines,  united  by  transverse  branches,  in 

the  minute  interspaces  between  the  fibres  (Fig. 
101);  so  that  it  is  probable  that  there  is  no  fibre, 
which  is  not  in  close  relation  with  a  capillary. 
The  number  of  bloodvessels  in  a  given  space  will 
of  course  be  greater,  where  the  fibres  and  the 
capillaries  are  both  small,  as  in  Mammals  and 
Birds,  than  where  they  are  of  larger  diameter, 
as  in  Reptiles  and  Fishes;  and  the  former  con- 
dition will  obviously  be  the  one  most  favorable 
CapiOary  network  of  Muscle.  to  the  performance  of  active  changes  between  the 
blood  and  the  muscle.  These  changes  consist, 

it  would  appear,  not  merely  in  the  nutrition  of  the  tissue ;  but  in  the  supply  of 
oxygen,  which  is  a  necessary  condition  of  the  excitement  of  its  activity.  We 
shall  hereafter  see,  indeed,  that  every  muscular  contraction  probably  involves 
the  disintegration  of  a  certain  amount  of  its  substance,  through  the  union  of 
oxygen,  supplied  by  arterial  blood,  with  its  elements ;  and  that  the  great  demand 
for  nutrition,  which  is  occasioned  by  muscular  activity,  is  for  the  purpose  of 
repairing  this  loss.  The  muscles  of  warm-blooded  animals  speedily  lose  their 
irritability,  after  the  supply  of  arterial  blood  has  been  suspended,  either  through 
the  cessation  of  the  general  circulation,  or  by  deficient  aeration  of  the  fluid. 
But  the  muscles  of  cold-blooded  animals,  which  are  very  inferior  in  the  energy 
and  rapidity  of  their  action,  preserve  their  properties  for  a  much  longer  period, 
after  the  deprivation  of  their  supply  of  arterial  blood;  in  accordance  with  the 
general  principle,  that,  the  lower  the  usual  amount  of  vital  energy,  the  longer 
is  its  persistence,  after  the  withdrawal  of  the  conditions  on  which  it  is  depend- 
ent. The  very  indisposition  to  a  change  of  composition,  on  which  the  less  ready 
action  depends,  produces  a  longer  retention  of  the  power  of  acting.  Much  dis- 
crepancy of  opinion  has  existed  amongst  anatomists,  as  to  the  presence  of  Lym- 
phatics in  Muscular  tissue.  The  microscopic  inquiries  of  Prof.  Kolliker  incline 
him  to  the  opinion  that  the  small  muscles  are  destitute  of  absorbents,  and  that 
the  few  lymphatics  which  seem  to  issue  from  some  of  the  larger  Muscles,  belong 
to  their  areolar  sheath  and  its  larger  subdivisions. 

309.  The  Striated  Muscles  (excepting  the  Heart)  are,  of  all  the  tissues  except 
the  skin,  those  most  copiously  supplied  with  Nerves.     These,  like  the  blood- 
vessels, lie  on  the  outside  of  the  Myolemma  of  the  several  fibres;  and  their  in- 
fluence must  consequently  be  excited  through  it.     The  general  arrangement  of 
these  nerves  is  shown  in  Fig.  102.     Their  ultimate  fibres  or  tubes  cannot  be 
said  to  terminate  anywhere  in  the  Muscular  substance ;  for,  after  issuing  from 
the  trunks,  they  form  a  series  of  loops,  which  return  either  to  the  same  trunk, 
or  to  an  adjacent  one.     The  occasional  appearance  of  a  termination  to  a  nervous 
fibril  is  caused  by  its  dipping  down  between  the  muscular  fibres,  to  pass  towards 
another  stratum.1     The  nerves  are  almost  exclusively  of  the  motor  kind;  but  a 

1  A  different  method  of  termination  has  been  discovered  by  Prof.  Wagner  in  the  muscu- 
lar nerves  of  the  frog,  and  by  Profs.  Miiller  and  Briicke  in  those  of  the  pike ;  the  ultimate 
nerve-fibres  themselves  undergoing  subdivision,  and  ending  by  exquisitely  fine  free  extre- 


STRUCTURE   OF   MUSCULAR   TISSUE. 


313 


few  sensory  are  blended  with  them.     We  see  this  most  clearly  in  cases,  in  which 
the  motor  and  sensory  trunks  supplying  the  muscles  are  distinct;  as  in  the 

Fig.  102.  "..* 


Form  of  the  terminating  loops  of  the  Nerves  in  the  Muscles. 

muscles  of  the  orbit. — The  non-striated  muscles  are  very  sparingly  supplied  with 
nerves;  and  these  are  derived  (for  the  most  part,  if  not  entirely),  from  the  Sym- 
pathetic system,  rather  than  from  the  Cerebro-Spinal. 

310.  The  development  of  striated  Muscular  fibre  commences,  according  to 
Schwann  and  Valentin,  in  the  development  of  a  linearly-arranged  series  of  cefls 
from  nuclei  lying  in  the  midst  of  a  soft  blastema.  At  the  points  of  contact  be- 
tween the  cells,  the  partitions  disappear ;  and  thus  a  continuous  tube  is  formed, 
which  seems  to  become  the  myolemma  of  the  fibre.  The  nuclei  of  the  original 
cells,  however,  still  remain;  and  besides  these,  the  tube  may  be  seen  to  contain 
a  number  of  granular  particles,  which  gradually  (according  to  the  observation  of 
Dr.  Sharpey1)  come  to  present  a  somewhat  regular  disposition  in  transverse  lines 
between  the  nuclei.  The  full  development  of  the  transverse  striae,  which  indi- 
cates the  complete  evolution  of  the  contained  nbrillae  within  the  myolemma,  does 
not  take  place  until  subsequently.  For  some  time,  the  nuclei  continue  to  be 
very  apparent,  in  consequence  of  their  projection  from  the  edges  of  the  fibre, 
and  of  the  smallness  of  its  diameter  (Fig.  103) ;  but  as  the  fibre  increases  in 
size,  they  become  more  embedded  in  its  substance;  and  in  the  muscular  fibre  of 
the  adult,  their  presence  can  only  be  made  evident  by  treating  the  fibre  with 
weak  acids  (such  as  the  citric  or  tartaric)  which  renders  the  nuclei  more  opaque, 
whilst  the  surrounding  structure  becomes  more  transparent.  (Fig.  104).  They 
are  usually  numerous  in  proportion  to  the  size  of  the  fibre. — The  development 
of  the  striated  fibre  has  more  recently  been  carefully  studied  by  M.  Lebert  in 
the  Heart  of  the  Chick.3  The  rhythmical  contractions  of  this  organ  become  very 
manifest  and  regular  towards  the  36th  hour  of  incubation :  nevertheless,  it  is  at 
this  time  composed  of  nothing  else  than  l( organo-plastic  globules"  or  elemen- 
tary cells  embedded  in  a  granular  blastema.  Between  the  fourth  and  fifth  days 
of  incubation  are  seen  in  the  midst  of  the  mass  of  globular  particles,  certain 

mities.  But  although  there  is  no  doubt  as  to  the  frequency  of  that  arrangement  in  cold- 
blooded Vertebrata,  as  well  as  in  many  Invertebrated  animals,  yet,  from  the  researches  of 
Prof.  Kolliker,  it  seems  certain  that  the  looped  arrangement  prevails  in  the  muscles  of 
Man  and  of  other  Mammalia ;  and  that  the  subdivision  of  the  nerve-fibres,  with  the  ter- 
mination of  the  fibres  in  free  extremities,  if  it  take  place  at  all,  is  quite  exceptional.  (See 
his  "  Mikroskopische  Anatomie,"  band  ii.  pp.  238-247.) 

1  See  his  Introduction  to  "  Quain's  Elements  of  Anatomy,"  vol.  i.  p.  324,  Am.  Ed. 

3  "Annales  des  Sci.  Nat.,"  Juin,  1849. 


314 


OF   THE   PRIMARY   TISSUES    OF   THE    HUMAN    BODY. 


elongated  sub-cylindrical  bodies,  sometimes  grouped  together  in  a  reticular  man- 
ner; these  bodies,  being  the  first  rudiments  of  the  muscular  fibres,  not  merely 


Fig.  103. 


Fig.  104. 


Muscular  Fibres  from  fcetal  pectoralis : — 
A,  from  Calf  at  two  months ;  B,  from  Human 
foetus  of  nine  months. 


Mass  of  Muscular  Fibres  from 
the  pectoralis  major  of  the  Hu- 
man foetus,  at  nine  months.  These 
fibres  have  been  immersed  in  a 
solution  of  tartaric  acid;  and 
their  numerous  corpuscles  turn- 
ed in  various  directions,  some  pre- 
senting nucleoli,  are  shown. 


in*  the  heart,  but  also  in  the  other  striated  muscles,  are  designated,  by  M.  Le- 
bert,  "myogenic  cells."  Between  the  seventh  and  eighth  days,  the  "organo- 
plastic  globules"  undergo  a  considerable  diminution,  and  the  muscular  substance 
presents  a  more  complete  development.  A  longitudinal  striation  shows  itself 
in  the  contents  of  the  cylinders,  which  seems  partly  due  to  the  grouping  of  the 
granular  particles  of  which  these  contents  consist;  the  transverse  striations  do 
not  show  themselves  until  some  time  afterwards.  Between  the  seventh  and 
ninth  days,  the  myogenic  cells  become  more  regularly  cylindrical  and  their  ex- 
tremities more  rounded ;  the  tendinous  fasciculi  then  begin  to  be  visible,  inclos- 
ing the  lower  part  of  the  cylinders,  without  having  as  yet  any  direct  relation  of 
continuity  with  them.  The  interior  of  the  cylinders  becomes  more  regularly 
striated  in  the  direction  of  its  length;  and  between  the  tenth  and  twelfth  days, 
the  transverse  striae  appear  on  the  surface,  and  multiply  rapidly,  becoming  at 
the  same  time  more  and  more  regular.  The  "  organo-plastic  globules,"  which 
at  first  separated  the  primitive  cylinders,  gradually  disappear;  the  cylinders 
approach  one  another ;  and  before  the  end  of  embryonic  life,  they  are  found  to  be 
grouped  into  fasciculi.  M.  Lebert  has  further  shown,  that  different  members  of 
the  animal  kingdom  permanently  exhibit  the  Muscular  fibre  in  the  different 
phases  of  development  here  described;1  and  it  appears  probable  that  the  smooth 
muscular  fibre-cells  of  Prof.  Kolliker  are  to  be  regarded  as  the  original  "  myo- 
genic cells,"  within  which  no  secondary  formation  has  taken  place. — There  seems 
every  probability  that  the  nuclei  of  the  parent-cells  continue  to  act  as  "  centres 
of  nutrition"  during  the  whole  life  of  each  fibre ;  furnishing  the  germs  from 
which  the  minute  secondary  cells,  that  compose  the  fibrillae,  are  developed  as  they 
are  required.  The  diameter  of  the  Muscular  fibre  of  the  foetus  is  not  above  one- 
third  of  that  which  it  possesses  in  the  adult ;  and  as  the  size  of  their  ultimate 
particles  is  the  same  in  both  cases,  their  number  must  be  greatly  multiplied 
during  the  growth  of  the  structure.  But  we  shall  find  reason  to  believe,  that 
a  decay  is  continually  taking  place  in  the  component  cells,  with  a  rapidity  pro- 

1  "Annales  des  Sci.  Nat.,"  Mars,  1850. 


STRUCTURE   OF   MUSCULAR   TISSUE.  315 

portional  to  the  functional  activity  of  the  Muscle ;  and  their  generation,  which 
occurs  as  constantly  when  the  nutrient  operations  proceed  in  their  regular  course, 
is  probably  accomplished  by  a  development  from  these  centres,  at  the  expense 
of  the  blood  with  which  the  muscle  is  copiously  supplied. 

311.  The  ordinary  rate  of  Nutrition  of  the  Muscular  tissue,  depends  upon 
its  functional  activity.     Every  exertion  of  its  vital  Contractility  involves — there 
is  good  reason  to  believe — a  waste  or  disintegration  of  a  proportional  amount  of 
its  substance ;  the  vital  force,  which  previously  manifested  itself  in  the  acts  of 
growth  and  development,  being  now  expended  in  the  form  of  mechanical  power ; 
and  the  living  tissue  being  consequently  reduced  to  the  condition  of  dead  mat- 
ter, and  being  thus  rendered  subject  to  decomposition,  which  it  previously  re- 
sisted.    Of  this  there  is  a  great  variety  of  evidence.     The  increase  of  the 
demand  for  food,  occasioned  by  Muscular  activity,  is  an  indication  that  the  nu- 
tritive operations  are  excited  by  it;  and  the  purpose  of  these  can  scarcely  be 
anything  else,  than  the  reparation  of  the  loss  which  the  Muscle  has  sustained. 
Again,  it  will  be  hereafter  shown  (§  324),  that  the  presence  of  Oxygen  is  essen- 
tial to  the  continued  development  of  the  contractile  force ;  and  there  is  evi- 
dence that,  in  this  development,  a  chemical  change  is  effected  in  the  substance 
of  the  Muscle,  which  is  of  a  nature  destructive  to  its  integrity  as  an  organized 
tissue.     For,  in  the  first  place,  the  researches  of  Helmholtz,  just  referred  to 
(§  307),  indicate  such  a  change,  from  the  comparative  results  of  Chemical  ana- 
lysis of  the  muscle,  before  and  after  the  violent  excitement  of  its  contractility ; 
and  this  is  more  definitely  shown  by  that  increase  in  the  lactic  acid  (§  49),  and 
in  the  creatine  and  creatinine  (§  61),  obtainable  from  Muscle,  which  is  conse- 
quent upon  its  functional  activity.     But  still  more  decided  evidence  is  given 
to  the  same  effect,  by  the  increase  in  the  excretions  which  is  observable  after 
Muscular  exertion ;  and  especially  by  the  augmentation  of  the  Carbonic  acid 
set  free  from  the  respiratory  organs,  and  by  that  of  the  Urea  eliminated  by  the 
kidneys.     The  amount  of  the  latter,  indeed,  may  be  regarded,  cseteris  paribuSj 
as  an   approximate   indication   of  the  quantity  of  Muscular  tissue  which  has 
undergone  disintegration ;  being  increased  or  diminished,  in  precise  proportion 
to  the  degree  of  exertion  to  which  the  Muscular  system  has  been  subjected. — 
It  cannot  but  be  regarded  as  a  probable  inference  from  these  facts,  that  the 
development  of  the  Contractile  force  is  in  some  way  dependent  upon  the  Che- 
mical change,  which  seems  to  be  so  essential  a  condition  of  it;  just  as  the  de- 
velopment of  the  Electric  force  of  the  galvanic  battery  is  dependent  upon  the 
new  Chemical  arrangements,  which  take  place  between  the  bodies  brought  to  act 
upon  one  another  in  its  trough. 

312.  The  frequently-renewed  exercise  of  Muscles,  by  producing  a  determina- 
tion of  blood  towards  them,  occasions  an  increase  in  their  nutrition ;  so  that  a 
larger  amount  of  new  tissue  becomes  developed,  and  the  muscles  are  increased 
in  size  and  vigor.     This  is  true,  not  only  of  the  whole  Muscular  system  when 
equally  exercised,  but  also  of  any  particular  set  of  muscles  which  is  more  used 
than  another.     Of  the  former  we  have  examples  in  those,  who  practise  a  sys- 
tem of  Gymnastics  adapted  to  call  the  various  muscles  alike  into  play ;  and  of 
the  latter,  in  the  limbs  of  individuals  who  follow  any  calling  that  habitually 
requires  the  exertion  of  either  pair,  to  the  partial  exclusion  of  the  other,  as  the 
arms  of  the  Smith,  or  the  legs  of  the  Opera-dancer.     But  this  increased  nutri- 
tion cannot  take  place,  unless  an  adequate  supply  of  food  be  afforded ;  and  if 
the  amount  of  nutritive  material  be  insufficient,  the  result  will  be  a  progressive 
diminution  in  the  size  and  power  of  the  muscles ;  which  will  manifest  itself 
the  more  rapidly,  as  the  amount  of  exertion,  and  consequently  the  degree  of 
waste,  is  greater.     Nor  can  it  be  effected,  if  the  exercise  be  too  constant ;  for  it 
is  during  the  intervals  of  repose,  that  the   reparation  of  the  muscular  tissue 
occurs ;  and  the  Muscular  system,  like  the  Nervous  (§  360),  may  be  worn  out 


316  OF   THE   PRIMARY   TISSUES    OF   THE    HUMAN   BODY. 

by  too  constant  use.  The  more  violent  the  action,  the  longer  will  be  the  period 
of  subsequent  repose  required  for  the  reparation  of  the  tissue  :  and  the  longest 
time  will  of  course  be  requisite,  when  (as  sometimes  occurs)  the  contractility  of 
the  muscle  is  so  completely  exhausted  by  excessive  stimulation  that  no  new 
manifestation  of  it  can  be  excited.  Nevertheless  it  is  certain,  that  there  must 
be  a  provision  in  some  Muscles,  for  the  continuance  of  their  nutrition  during 
their  state  of  activity ;  for  in  no  other  way  could  the  Heart  and  Respiratory 
muscles,  which  are  in  unceasing  action  during  the  whole  of  life,  be  kept  in  a 
state  fit  for  the  discharge  of  their  functions. 

313.  But,  on  the  other  hand,  the  Muscular  tissue,  like  all  the  softer  and 
more  decomposable  portions  of  the  organized  fabric,  has  a  limited  term  of  exist- 
ence (§  114) ;  and  hence,  even  if  its  contractility  be  not  called  into  exercise,  it 
undergoes  a  gradual  disintegration,  so  soon  as  all  the  nutritive  changes  of  which 
its  component  cells  are  susceptible,  have  been  completed.  This  change  seems 
to  be  a  necessary  consequence  of  the  high  temperature  of  the  bodies  of  warm- 
blooded animals ;  for  it  does  not  occur  with  nearly  the  same  rapidity  in  cold- 
blooded Animals,  nor  in  the  hybernating  condition  of  certain  warm-blooded 
Mammalia;  indeed,  when  the  temperature  of  the  body  is  reduced  to  within  a 
few  degrees  of  the  freezing  point,  no  chemical  change  seems  possible  in  muscle, 
— its  spontaneous  decay,  and  its  vital  activity,  being  alike  checked.  Now  when 
a  Muscle  or  set  of  Muscles,  in  a  warm-blooded  animal,  is  reduced  to  a  state  of 
prolonged  inactivity,  from  whatever  cause,  its  supply  of  blood  is  diminished, 
and  its  spontaneous  decay  is  not  compensated  by  an  equally  active  renewal ;  so 
that,  in  time,  the  characters  of  the  structure  are  changed,  and  its  distinguish- 
ing properties  are  no  longer  presented.  Thus  it  was  found  by  Dr.  John  Reid,1 
that,  in  a  rabbit,  a  portion  of  whose  sciatic  nerve  had  been  removed  on  one  side, 
the  muscles  of  that  leg  were  but  very  feebly  excited  to  contraction  by  Gal- 
vanism, after  the  lapse  of  seven  weeks.  The  change  in  their  nutrition  was 
evident  to  the  eye,  and  was  made  equally  apparent  by  the  balance.  The  mus- 
cles of  the  paralyzed  limb  were  much  smaller,  paler,  and  softer,  than  the  cor- 
responding muscles  of  the  opposite  leg ;  and  they  scarcely  weighed  more  than 
half — being  only  170  grains,  whilst  the  others  were  327  grains.  It  was  found 
also,  that  a  perceptible  difference  existed  in  the  size  of  the  bones  of  the  leg, 
even  after  so  short  an  interval  had  elapsed  :  the  tibia  and  fibula  of  the  para- 
lyzed limb  weighing  only  81  grains,  whilst  those  of  the  sound  limb  weighed  89 
grains.  On  examining  the  muscular  fibres  with  the  microscope,  it  was  found 
that  those  of  the  paralyzed  leg  were  considerably  smaller  than  those  of  the 
sound  limb,  and  presented  a  somewhat  shrivelled  appearance ;  and  that  the 
longitudinal  and  transverse  striae  were  much  less  distinct.  So  in  persons  whose 
lower  extremities  have  been  long  disused,  the  muscles  first  become  pale  and 
flabby ;  their  bulk  gradually  diminishes ;  their  contractile  force  progressively 
decreases,  and  at  last  departs  almost  entirely;  and  their  proper  structure  is 
replaced  by  a  deposit  of  fat,  intermixed  with  ordinary  fibrous  tissue,  in  which 
few  or  no  characteristically-striated  muscular  fibres  can  be  detected.  But  mus- 
cles that  have  for  some  time  remained  in  this  condition  may  be  gradually 
brought  back  to  their  original  state  by  exercise,  provided  that  the  feeblest 
contractility  remains ;  for  every  action  which  they  can  be  made  to  perform, 
determines  an  augmented  flow  of  blood  through  the  tissue,  and  gives  rise  to  an 
improvement  in  its  nutrition,  which  in  its  turn  increases  its  contractility,  and 
renders  it  capable  of  more  vigorous  action.  This  principle  is  of  great  import- 
ance in  the  treatment  of  various  forms  of  paralysis  (especially  the  hysterical), 
in  which  the  muscles  are  thrown  out  of  use  by  the  suspension  of  the  functional 

1  "Edinburgh  Monthly  Journal  of  Medical  Science,"  May,  1841 ;  and  "Physiological, 
Anatomical,  and  Pathological  Researches,"  p.  10. 


FUNCTIONS    OF    MUSCULAR   TISSUE.  317 

power  of  the  nerves ;  for,  when  the  latter  have  recovered  their  capacity,  the 
muscles  refuse  obedience  to  their  stimulation,  and  can  only  be  brought  to  act 
by  persevering  and  judiciously  contrived  exercise.  But  notwithstanding  the 
energy  of  nutrition  in  Muscular  tissue,  the  rapid  interstitial  change  which 
takes  place  in  it  when  actively  exercised,  and  the  complete  restoration  of  its 
normal  constitution  after  degeneration  from  disuse,  it  is  doubtful  if  any  true  re- 
generation ever  takes  place  in  it,  when  there  has  been  actual  loss  of  substance. 
Wounds  of  Muscles  are  united  by  Areolar  tissue,  which  gradually  becomes  con- 
densed ;  but  its  fibres  never  require  any  degree  of  contractility. 

314.  The  property  of  Contractility  on  the  application  of  a  stimulus,  appears 
to  be  limited,  in  the  fully-developed  Human  organism,  to  the  two  forms  of  Mus- 
cular tissue  which  have  been  now  described ;  several  tissues  which  exhibit  it,  and 
which  yet  do  not  present  any  obvious  evidence  of  muscular  structure,  having 
been  shown  by  Prof.  Kolliker  to  contain  the  fusiform  cells  which  constitute 
the  non-striated  fibre.     It  is  characteristic  of  Animal  contractility,  as  distin- 
guished from  that  which  is  concerned  in  producing  the  sensible  movements  of 
Plants,  that  whilst  it  is  capable  of  being  called  into  play  by  stimuli  of  various 
kinds  (mechanical,  chemical,  electrical,  &c.),  which  also  act  upon  the  Vegetable 
contractile  tissues,  yet  it  is  excited  in  addition  by  the  stimulus  of  Innervation, 
that  is,  by  the  operation  of  Nervous  force,  to  which  the  tissues  of  Plants  are 
not  amenable.1     And  it  is  when  its  peculiar  property  is  thus  made  to  display 
itself,  that  the  Muscular  tissue  becomes  the  instrument  of  the  operation  of  the 
Nervous  system  upon  the  external  world,  and  thus  performs  an  important  part 
in  the  purely  Animal  Functions.     The  Muscular  tissue,  however,  is  not  always 
thus  called  into  activity  through  the  medium  of  the  Nervous  system;  for  it  is 
employed  to  execute  numerous  movements,  which  are  immediately  connected 
with  the  maintenance  of  the  Organic  functions,  and  in  which  the  influence  of 
Innervation  seems  to  be  but  little  concerned ;  its  contractility  being  excited  to 
action  by  stimuli  directly  applied  to  itself.     The  two  forms  of  Muscular  tissue, 
the  striated  and  the  non-striated,  are  for  the  most  part  appropriated  to  these 
two  purposes  respectively ;  the  former  being  the  kind  most  readily  acted  on 
through  the  Nervous  system,  and  being  invariably  employed  in  the  Muscles 
that  are  ordinarily  called  into  action  by  its  influence ;  whilst  the  latter  is  with 
difficulty  excited  to  contraction  through  the  Nervous  System,  and  is  usually 
employed  in  Muscles  whose  action  is  altogether  uncontrollable  by  the  will. 

315.  This  general  property  of  Contractility  shows  itself  under  two  forms,  which 
are  alike  distinct  in  the  mode  of  their  action,  and  in  the  conditions  requisite  for 
its  excitation. — Its  most  obvious  and  striking  manifestations  present  themselves 
in  the  Voluntary  muscles  and  in  the  Heart;  which,  when  in  activity,  exhibit 
powerful  contractions  tending  to  alternate  with  relaxations.     The  modification 
of  contractility  which  is  concerned  in  producing  these,  is  distinguished  as  Irri- 
tability.— On  the  other  hand,  we  find  that  the  muscles  exhibit  a  tendency  to  a 
moderate  and  permanent  contraction,  which  is  not  shown  by  them  when  they 
are  dead,  and  which  cannot,  therefore,  be  the  result  of  elasticity,  or  of  any 
simple  physical  property ;  and  this  contraction,  instead  of  being  consequent 
upon  stimulation  through  the  nerves,  is  especially  excited  by  changes  of  tem- 
perature in  the  tissue  itself.     This  endowment,  which  seems  to  exist  in  the 
greatest  amount  in  certain  forms  of  the  non-striated  muscle  is  called   Tonicity. 
— These  two  modifications  of  Muscular  Contractility  require  a  separate  consi- 
deration. 

316.  Of  Muscular  Irritability. — All  Muscular  Fibres  which  are  in  possession 
of  vital  activity,  may  be  caused  to  contract  by  stimuli  directly  applied  to  them- 
selves ;  and  these  stimuli  may  be  of  different  kinds.     The  simplest  is  the  con- 

1  See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  CHAP  xix.,  Am.  Ed. 


318  OF   THE   PRIMARY   TISSUES    OF   THE    HUMAN    BODY. 

tact  of  a  solid  substance,  especially  if  it  be  pointed ;  thus  we  may  excite  con- 
tractions in  Muscular  fibres,  by  simply  touching  them  with  the  point  of  a  needle 
or  of  a  scalpel.  Most  substances  of  strong  chemical  action,  such  as  acids  and 
alkalies,  will  excite  the  fibres  to  contraction,  when  directly  applied  to  themselves; 
but  the  most  powerful  agent  of  all  is  Electricity. — If  we  irritate  mechanically 
a  portion  of  a  muscle  composed  of  striated  fibre,  the  biceps,  for  example,  the 
fasciculus  of  fibres  which  is  touched  will  immediately  contract,  and  that  one 
only ;  and  the  contracted  fasciculus  will  soon  relax,  without  communicating  its 
movements  to  any  other.  The  Heart,  however,  exhibits  a  different  action,  which 
is  probably  dependent  upon  the  peculiar  arrangement  of  its  fibres,  whereby  the 
contraction  of  one  set  gives  a  mechanical  stimulation  to  others ;  for  the  muscular 
substance  of  a  large  part  of  the  organ  is  thrown  into  rapid  and  energetic  con- 
traction, by  a  stimulus  applied  at  any  one  point ;  and  this  contraction  is  speedily 
followed  by  relaxation,  which  is  again  succeeded  by  a  number  of  alternating 
contractions  and  relaxations.  On  the  other  hand,  if  we  apply  a  similar  irrita- 
tion to  a  portion  of  non-striated  fibre,  as  that  of  the  Intestinal  canal,  the  fasci- 
culus which  is  stimulated  will  contract  less  suddenly,  but  ultimately  to  a  greater 
amount;  its  relaxation  will  be  less  speedy;  and,  before  it  takes  place,  other 
fasciculi  in  the  neighborhood  begin  to  contract ;  their  contraction  propagates 
itself  to  others;  and  so  on.  In  this  manner,  successive  contractions  and  relaxa- 
tions may  be  produced  through  a  considerable  part  of  the  canal,  by  a  single 
prick  with  a  scalpel ;  a  sort  of  wave  of  contraction  being  transmitted  in  the 
direction  of  its  length,  and  being  followed  by  relaxation.  Again,  in  the  Mus- 
cular structure  of  the  Bladder  and  Uterus  (when  the  latter  is  fully  developed), 
direct  irritation  excites  immediate  and  powerful  contractions,  which  extend 
beyond  the  fasciculus  actually  irritated,  and  produce  a  great  degree  of  shorten- 
ing ;  but  they  do  not  alternate,  in  the  healthy  state,  with  any  rapid  and  decided 
elongation.  And  in  the  muscular  tissue  of  the  middle  coat  of  the  Arteries,  the 
contraction  takes  place  nearly  in  the  same  manner ;  a  considerable  degree  of 
shortening  being  effected  by  the  contraction  of  other  fasciculi  than  those  directly 
irritated,  and  this  shortening  not  giving  way  speedily  to  relaxation ;  but  a  pro- 
longed application  of  the  stimulus  is  often  necessary  to  produce  the  effect. — 
The  effects  of  Electrical  stimulation  applied  to  the  Muscles  themselves,  are  very 
similar ;  but  it  is  more  difficult  to  confine  the  irritation  to  particular  fasciculi  of 
a  voluntary  muscle,  and  more  easy  to  throw  the  whole  mass  into  contraction  at 
once  by  the  transmission  of  a  slight  charge  through  it ;  and  on  certain  forms 
of  the  non-striated  fibre,  the  electric  stimulus  produces  effects  more  decided  than 
can  be  evoked  in  any  other  way.  The  difference  in  the  endowments  of  the  two 
kinds  of  tissue  is  particularly  well  seen,  when  they  are  subjected  to  the  magneto- 
galvanic  apparatus,  which  transmits  a  rapid  succession  of  slight  electric  shocks ; 
for  these,  in  the  striated  muscles,  immediately  excite  a  state  of  rigid  contraction 
which  lasts  as  long  as  the  stimulus  is  transmitted,  but  ceases  immediately  that 
it  is  withdrawn ;  whilst  in  the  non-striated  fibres,  the  contraction  is  slowly  ex- 
cited, sometimes  alternates  with  rest,  and  continues  for  a  time  after  the  electric 
discharges  have  ceased.  Of  this  form  of  contractility,  the  muscular  coats  of 
the  smaller  arteries  afford  a  particularly  good  example ;  for  they  may  be  made 
to  contract  by  the  magneto-galvanic  apparatus,  until  they  become  quite  imper- 
vious to  blood ;  and  yet  the  contraction  neither  takes  place  immediately  upon 
the  application  of  the  stimulus,  nor  does  it  give  place  to  relaxation  directly  that 
it  is  intermitted.1 

317.  On  the  other  hand,  when  the  stimuli  which  excite  Muscular  Contractility 
are  applied  to  the  nerves  which  supply  any  muscle  composed  of  striated  fibre  (the 

1  See  Prof.  Weber's  researches  upon  this  subject,  in  Wagner's  "  Ilandworterbuch  der 
Physiologic,"  Art.  "Muskelbewegung;"  and  "  Mailer's  Archiv.,"  1847,  band  ii. 


FUNCTIONS   OF   MUSCULAR   TISSUE.  319 

Heart  only  excepted),  they  produce  a  simultaneous  contraction  in  the  whole 
muscle ;  the  effect  of  the  stimulus  being  at  once  exerted  upon  every  part  of  it. 
The  contraction  speedily  alternates  with  relaxation,  unless  the  operation  of  the 
stimulus  be  continued — as  when  an  electric  current  is  propagated  without  inter- 
mission along  the  nerve-trunks — in  which  case  the  contraction  lasts  as  long  as 
the  stimulus  is  continuously  applied,  but  ceases  as  soon  as  it  is  withdrawn.  Eut 
it  has  been  shown  by  Volkmann,1  that,  if  the  electric  stimulus  be  applied  to  the 
central  organs  from  which  the  motor  nerves  arise,  the  muscular  contraction  con- 
tinues for  some  time  after  its  withdrawal.  Further,  he  found  that  when  the 
continuous  electric  current  was  passed  through  incident  or  excitor  nerves,  it 
produced  alternating  movements  of  contraction  and  relaxation,  in  the  muscles 
which  were-  thus  called  into  play  by  reflex  stimulation. — The  ordinary  actions 
of  the  non-striated  fibre,  on  the  other  hand,  are  not  easily  excitable  by  stimuli 
applied  to  their  nerves;  indeed,  many  Physiologists  have  denied  the  possibility 
of  producing  them  through  this  channel.  Abundant  evidence  that  they  are  thus 
excitable,  however,  although  the  excitability  speedily  ceases  after  death,  will  be 
given  hereafter  (CHAP.  xiv.  SECT.  6).  The  results  of  Volkmann' s  recent  elec- 
trical experiments  upon  the  Heart  and  the  Intestinal  Canal  are  of  much  interest. 
He  found  that  neither  of  these  organs  is  thrown  into  fixed  contraction,  when  the 
continuous  electric  current  is  applied  to  the  Brain  and  Spinal  Cord;  whence  he 
concludes  that  these  organs  are  not  the  centres  of  their  motor  nerves.  On  the 
other  hand,  alternating  contractions  and  relaxations  were  produced  on  applying 
the  continuous  current  to  the  spinal  cord,  the  par  vagum,  and  the  sympathetic 
nerves ;  whence  it  may  be  concluded  that  these  parts  contain  afferent  fibres, 
which  excite  motion  through  centres  that  can  scarcely  be  any  others  than  the 
ganglia  of  the  Sympathetic  system.  When  the  Heart  is  removed  from  the  body, 
and  is  left  entire,  it  may  be  thrown  into  a  state  of  fixed  contraction,  which  lasts 
after  the  cessation  of  the  current;  whence  it  may  be  concluded,  that  it  contains 
the  centre  of  its  own  motor  nerves.2 — These  experiments,  hpwever,  by  no  means 
warrant  the  conclusion,  that  the  ordinary  actions  of  these  muscular  organs  are 
dependent  upon  the  agency  of  their  nerves;  a  doctrine  which  is  opposed  by  a 
variety  of  evidence. 

318.  The  general  fact,  that  Muscular  contraction  alternates  with  relaxation 
at  no  long  intervals,  is  most  evident  in  the  rhythmical  movements  of  the  Heart,3 
and  in  the  peristaltic  action  of  the  Intestinal  Canal ;  since,  in  these  parts,  the 
whole  or  a  large  proportion  of  the  fibres  seem  to  contract  together,  and  then 
shortly  relax.  But  it  is  probably  no  less  true,  as  formerly  stated  (§  303),  of 
the  individual  fibres  of  those  muscles,  which  are  kept  in  a  state  of  contraction 
by  a  stimulus  transmitted  through  their  nerves ;  since  none  of  them  appear, 
under  ordinary  circumstances  at  least,  to  remain  in  a  contracted  state  for  any 
length  of  time;  a  constant  interchange  of  condition  taking  place  among  the 

1  "Muller's  Archiv.,"  1844,  No.  5,  p.  407. 

2  Op.  cit. ;  and  Mr.  Paget's  "Report"  for  1845,  in  "Brit,  and  For.  Med.  Rev.,"  July, 
1846. 

3  Some  curious  rhythmical  movements  have  been  observed  by  M.  Brown-Sequard,  in  the 
diaphragm,  intercostals,  and  some  of  the  muscles  of  locomotion,  both  after  death,  and  after 
section  of  their  nerves  during  life.     These  movements  could  not  be  in  any  way  dependent 
upon  reflex  action,  because  they  took  place  when  the  muscles  were  completely  cut  oif  from 
the  nervous  centres ;  sometimes  to  the  number  of  from  5  to  20  in  a  minute,  and  for  as  long 
as  a  quarter  of  an  hour  after  death ;  and  occasionally  recurring,  in  a  living  animal,  for 
many  months  afterwards,  especially  when  the  respiration  was  impeded,  and  the  circulation 
hurried. — The  fact  is  of  much  importance,  as  showing  that  the  rhythmical  movements  of 
the  heart  are  by  no  means  so  exceptional  (among  the  muscles  composed  of  striated  fibre) 
as  they  are  usually  accounted ;  and  also  that  there  is  a  tendency  to  rhythmical  movement 
in  the  muscles  themselves,  altogether  independent  of  the  excitement  to  action  which  they 
receive  through  the  nervous  system.  ("Gazette  Medicale,"  Dec.  22,  1849.) 


320  OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 

fibres,  some  contracting  whilst  others  are  relaxing,  and  vice  versti.  It  is  difficult 
to  speak  with  confidence,  however,  in  regard  to  the  condition  of  the  individual 
fibres  of  a  muscle,  that  is  thrown  into  a  state  of  continued  spasmodic  contraction ; 
such  as  that  produced  by  the  application  of  the  electric  current  to  the  centre  of 
its  motor  nerves  (§  317).  A  state  of  this  kind  is  often  of  considerable  duration. 
Thus  the  Author  has  known  a  case  of  Hysteric  Trismus,  in  which  the  jaws 
remained  closed  with  the  greatest  firmness  during  five  days.  Whether  the 
individual  fibres,  in  such  instances,  maintain  a  state  of  contraction  without  inter- 
mission, or  whether  the  contraction  of  the  entire  muscle  is  kept  up  by  a  con- 
tinual interchange  of  the  fibres  actually  engaged,  is  a  very  curious  subject  for 
inquiry. 

319.  Muscles  do  not  lose  their  Irritability  immediately  on  the  general  death 
of  the  system,  which  must  be  considered  as  taking  place  when  the  circulation 
ceases  without  a  power  of  renewal ;  in  cold-blooded  animals  it  is  retained  much 
longer  after  this  period  than  in  the  higher  Vertebrata,  in  some  of  which  it  dis- 
appears within  an  hour.     The  muscles  of  young  animals  generally  retain  their 
irritability  for  a  longer  time  than  those  of  adults;  on  the  other  hand,  those  of 
Birds  lose  their  irritability  sooner  than  those  of  Mammalia.     Hence,  as  a  general 
rule,  the  duration  of  the  irritability  is  inversely  as  the  amount  of  respiration. 
From  experiments  on  the  bodies  of  executed  criminals,  who  were  previously  in 
good  health,  Nysten  ascertained  that,  in  the  Human  subject,  the  irritability  of 
the  several  muscular  structures  departs  in  the  following  time  and  order :     The 
left  ventricle  of  the  heart  first;  the  intestinal  canal  at  the  end  of  forty-five  or 
fifty-five  minutes ;  the  urinary  bladder  nearly  at  the  same  time ;  the  right  ven- 
tricle after  the  lapse  of  an  hour;  the  oesophagus  at  the  expiration  of  an  hour 
and  a  half;  the  iris  a  quarter  of  an  hour  later;  the  muscles  of  Animal  life 
somewhat  later;  and  lastly,  the  auricles  of  the  heart,  especially  the  right,  which 
in  one  instance  contracted  under  the  influence  of  galvanism  sixteen  and  a  half 
hours  after  death.  Itwill  be  presently  shown  that  the  departure  of  the  irritability 
is  entirely  dependent  upon  the  cessation  of  the  circulation;  and  that  it  may  be  pre- 
vented from  disappearing,  and  may  even  be  recalled  after  it  has  ceased  to  manifest 
itself,  by  transmitting  a  current  of  arterial  blood  through  the  muscles  (§  323). 

320.  Muscular  Irritability  is  deadened  by  many  substances,  especially  by 
those  which  have  a  narcotic  or  sedative  action  on  the  Nervous  system.     In  car- 
bonic acid  gas,  hydrogen,  carbonic  oxide,  or  sulphurous  acid  gas,  muscles  con- 
tract very  feebly,  or  not  at  all,  when  stimulated;  whilst  in  oxygen  they  retain 
their  irritability  longer  than  usual.     Narcotic  substances,  such  as  a  watery  solu- 
tion of  opium,  when  applied  directly  to  the  muscles,  have  an  immediate  and 
powerful  effect  in  diminishing  or  even  destroying  their  irritability ;  this  effect 
is  also  produced,  though  in  a  less  powerful  degree,  by  injecting  these  substances 
into  the  blood.     In  the  same  manner,  venous  blood,  charged  with  carbonic  acid, 
and  deficient  in  oxygen,  has  the  effect  of  a  poison  upon  muscles;  diminishing 
their  irritability,  when  it  continues  to  circulate  through  them,  to  such  a  degree, 
that  they  sometimes  lose  it  almost  as  soon  as  the  circulation  ceases,  as  is  seen  in 
those  who  have  died  from  gradual  and  therefore  prolonged  Asphyxia.     The  un- 
favorable influence  of  venous  blood  is  also  shown  in  the  Morbus  Creruleus ; 
patients  affected  with  which  are  incapable  of  any  considerable  muscular  exertion. 
Although  most  of  the  stimuli  which  occasion  the  contraction  of  muscles,  when 
directly  applied  to  their  fibres,  operate  also  when  applied  to  their  motor  nerves, 
the  same  does  not  hold  good  in  regard  to  those  agents  which  diminish  irrita- 
bility.    It  is  a  fact  of  some  importance,  in  relation  to  the  disputed  question  of 
the  connection  of  muscular  irritability  with  the  nervous  system,  that  when, 
by  the  application  of  narcotic  substances  to  the  Nerves,  their  vital  proper- 
ties are  destroyed,  the  irritability  of  the  Muscle  may  remain  for  some  time 
longer;  showing  that  the  latter  must  be  independent  of  the  former.     This  was 


FUNCTIONS   OF   MUSCULAR   TISSUE.  321 

proved  some  years  since  by  Dr.  W.  H.  Madden  f  and  Dr.  Harless  has  more 
recently  found  that  when  the  nervous  system  had  been  rendered,  by  the  inhala- 
tion of  ether,  utterly  incapable  of  conveying  a  galvanic  stimulus,  applied  either 
to  the  nervous  centres  or  to  the  nerve-trunks,  the  same  stimulus,  applied  directly 
to  the  muscles,  would  immediately  throw  them  into  powerful  contraction.3 
Various  other  experimenters  have  shown,  that  when  the  nerves  supplying  the 
muscles  of  a  limb  are  divided,  and  the  animals  are  allowed  to  live,  excitants 
applied  to  the  nerves  beyond  the  point  of  division  fail  to  produce  muscular  con- 
tractions, long  before  they  cease  to  do  so  when  applied  to  the  muscles  themselves. 
Hence  it  is  obvious  that  the  activity  of  the  Nervous  system  is  not  essential  to 
the  manifestation  of  the  characteristic  endowment  of  the  Muscular.3 

321.  We  find,  however,  that  sudden  and  severe  injuries  of  the  Nervous  cen- 
tres have  power  to  impair,  directly  and  instantaneously,  or  even  to  destroy,  the 
contractility  of  the  whole  Muscular  system ;  so  that  death  immediately  results, 
and  no  irritability  subsequently  remains.  It  is  in  this  manner  that  the  sudden 
destruction  of  the  Brain  and  Spinal  Cord,  especially  of  the  latter,  occasions  the 
immediate  cessation  of  the  Heart's  action ;  though  they  may  be  gradually  re- 
moved, without  any  considerable  effect  upon  it.  Severe  concussion  has  the  same 
effect ;  hence  the  Syncope  which  immediately  displays  itself.  It  is  sometimes 
an  important  question  in  Forensic  Medicine,  whether  an  individual,  who  has  died 
from  the  effects  of  a  blow  upon  the  head,  could  have  moved  from  the  place 
where  the  blow  was  inflicted.  If  there  be  found,  as  is  frequently  the  case,  no 
sensible  disorganization  of  the  Brain,  the  death  must  be  attributed  to  the  con- 
cussion, and  must  have  been  in  that  case  immediate.  If,  on  the  other  hand, 
effusion  of  blood  has  taken  place  within  the  cranium,  to  any  considerable  extent, 
it  is  probable  that  the  first  effects  of  the  blow  were  in  some  degree  recovered 
from,  and  that  the  circulation  was  re-established.  It  is  not  essential,  however, 
that  the  impression  should  be  primarily  made  upon  the  Cerebro-Spinal  system. 
The  well-known  fact  of  sudden  death  not  unfrequently  resulting  from  a  blow  on 
the  stomach,  especially  after  a  full  meal,  without  any  perceptible  lesion  of  the 
viscera,  clearly  indicates  that  an  impression  upon  the  widely-spread  cceliac  plexus 
of  Sympathetic  nerves  (which  will  be  much  more  extensively  communicated  to 
them  when  the  stomach  is  full  than  when  it  is  empty),  may  cause  the  imme- 
diate cessation  of  the  Heart's  action,  in  the  same  manner  as  a  violent  injury  of 
the  Brain  or  Spinal  Cord.  In  all  these  cases,  the  whole  vitality  of  the  system 
appears  to  be  destroyed  at  once ;  for  the  processes  which  would  otherwise  suc- 
ceed to  the  injury,  and  which,  after  other  kinds  of  death  less  sudden  in  their 
character,  produce  evident  changes  in  the  part  of  the  surface  that  has  imme- 
diately received  it,  are  here  entirely  prevented.  An  instance  is  on  record,  in 
which  a  criminal  under  sentence  of  death  determined  to  anticipate  the  law 
by  self-destruction.  Having  no  other  means  of  accomplishing  his  purpose,  he 
stooped  his  head  and  ran  violently  against  the  wall  of  his  cell ;  he  immediately 
fell  dead;  and  no  mark  of  contusion  showed  itself  on  his  forehead.  The  same 
absence  of  the  usual  results  is  to  be  noticed,  in  the  case  of  blows  on  the  stomach. 
Yet  it  is  well  known  that  many  of  the  ordinary  vital  processes  will  take  place 
in  the  injured  parts,  after  death  of  a  more  lingering  nature ;  the  vitality  of  the 
individual  organs  not  being  destroyed  immediately  on  the  severance  of  the  chain 
which  binds  together  the  different  functions. — The  influence  of  severe  impres- 

1  "Reports  of  the  British  Association,"  1887,  p.  103. 

2  "Miiller's  Archiv.,"  1847,  band  ii. 

3  [Dr.  Brown-Sequard  has  shown  that,  when  the  muscles  of  one  limb  have  been  paralyzed 
by  section  of  their  nerves,  their  irritability  lasts  much  longer  after  death  than  that  of  the 
muscles  of  the  other  limb,  and  their  cadaveric  rigidity  is  much  later  in  making  its  appear- 
ance.   This  fact  would  also  seem  to  prove  that  the  irritability  of  the  muscles  is  independent 
of  the  nerves. — "Gazette  Medicale,"  Fev.  et  Mars,  1852. — Ed.] 

21 


322  OP   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 

sions  on  the  Nervous  system,  in  diminishing,  where  it  does  not  altogether  de- 
stroy, Muscular  irritability,  is  well  seen  in  the  operation  of  severe  injuries  affect- 
ing vital  organs,  or  extending  over  a  large  part  of  the  surface,  in  depressing  the 
Heart's  action.  This  is  a  well-known  result  of  severe  burns,  especially  in  chil- 
dren, whose  nervous  system  is  more  susceptible  of  such  impressions  than  that 
of  the  adult;  also  of  the  rupture  of  the  alimentary  canal,  of  the  bladder  or 
uterus;  and  of  the  shattering  of  one  of  the  extremities,  by  violence  affecting  a 
large  part  of  their  substance.  In  all  these  cases,  the  sufferer  is  in  the  same 
condition  with  one  who  has  received  a  severe  blow  on  the  head  that  does  not 
quite  stun  him ;  the  shock  immediately  diminishes  the  muscular  contractility  of 
the  whole  system;  and  its  influence  on  the  heart,  which  of  course  manifests 
itself  most  conspicuously,  produces  a  degree  of  depression,  which  is  frequently 
never  recovered  from,  and  which  at  any  rate  renders  necessary  the  employment 
of  stimulants,  for  the  purpose  of  counteracting  this  very  dangerous  effect.1 
Excessive  mental  Emotion,  of  a  kind  not  in  itself  depressing,  may  occasion  the 
sudden  cessation  of  the  heart's  action,  and  a  general  loss  of  muscular  irritability; 
and  it  is  well  known  that  muscular  power  is  greatly  diminished  by  emotions, 
which  produce  no  other  direct  action. 

322.  There  is  no  evidence  that  Muscular  irritability  can  be  increased  by  any 
cause  operating  through  the  Nervous  system.     It  is  quite  true  that,  under  the 
agency  of  alcohol,  nitrous  oxide,  or  some  of  the  other  substances  that  rank  as 
stimulants,  individuals  can  perform  actions  requiring  a  degree  of  strength,  which 
they  cannot  exert  under  ordinary  circumstances.     But  it  does  not  hence  follow 
that  the  irritability  is  increased;  since  the  energy  of  the  movement  is  attributa- 
ble solely  to  the  increase  of  the  nervous  power  by  which  it  is  excited,  and  to  the 
unusual  number  of  fibres  called  into  simultaneous  contraction.     We  have  numer- 
ous examples  of  this  kind,  in  cases  in  which  the  stimulus  is  purely  mental ;  a 
state  of  general  emotional  excitement  producing  a  temporary  augmentation  of 
the  nerve-force  transmitted  to  the  muscular  system,  as  is  seen  in  violent  fits  of 
passion,  and  still  more  in  Mania;  or  an  extraordinary  amount  of  nerve-force 
being  determined  to  particular  groups  of  muscles  by  the  concentration  of  the 
attention  upon  them,  in  peculiar  states  of  Abstraction,  without  any  emotional 
excitement  whatever  (see  CHAP.  xiv.  SECT.  7).     It  is  well  known  that  stimu- 
lating agents,  which  temporarily  increase  Muscular  power,  primarily  excite  the 
Nervous  system ;   as  is  shown  by  the  increased  mental  activity  which  results 
from  the  moderate  use  of  alcohol,  nitrous  oxide,  opium,  &c. ;  and  it  does  not 
seem  necessary,  therefore,  to  go  further,  in  search  of  an  explanation  of  their 
effect  on  muscular  action. 

323.  There  can  be  no  question  that  the  condition  most  essential  to  the  main- 
tenance of  Muscular  contractility,  is  an  adequate  supply  of  arterial  blood.     It 
is  well  known  that,  when  a  ligature  is  applied  to  a  large  arterial  trunk  in  the 
Human  subject,  there  is  not  only  a  deficiency  of  sensibility  in  the  surface,  but 
also  a  partial  or  complete  suspension  of  muscular  power,  until  the  collateral 
circulation  is  established.     The  same  result  has  been  constantly  attained,  in 
experiments  upon  the  lower  Animals;    the  contractility  of  the  muscle  being 
impaired  or  altogether  extinguished,  when  the  flow  of  blood  into  it  was  arrested ; 

1  The  large  quantity  of  stimulus  which  can  be  borne  even  by  children,  suffering  under 
severe  burns,  is  very  extraordinary.  There  can  be  no  doubt  that  many  lives  have  been 
saved  by  the  judicious  administration  of  them,  to  an  amount,  which  would  a  priori  have 
been  judged  in  itself  fatal ;  but  that  many  more  have  been  sacrificed  to  neglect,  even  on 
the  part  of  those  whose  duty  it  is  to  watch  the  indications  with  the  closest  attention.  The 
Author's  observations  lead  him  to  believe  that  Hospital  Nurses  very  commonly  make  up 
their  minds  that  children,  who  have  met  with  severe  burns,  must  die ;  and  that,  unless 
closely  watched,  they  neglect  the  means  of  which  Science  and  Experience  alike  dictate 
the  free  employment. 


FUNCTIONS    OF   MUSCULAR   TISSUE.  323 

and  being  recovered  again,  when  the  supply  of  blood  was  restored. — The  recent 
experiments  of  M.  Brown-Sequard  on  this  subject  are  still  more  satisfactory,  as 
showing  that  the  contractility  of  muscles  may  be  restored  by  the  transmission 
of  aerated  blood  through  them,  after  it  has  entirely  ceased,  and  has  even  given 
place  to  cadaveric  rigidity  (§  333).  Thus  he  found  that  when  he  connected  the 
aorta  and  vena  cava  of  the  body  of  a  rabbit  which  had  been  some  time  dead,  and 
in  which  the  cadaveric  rigidity  had  already  manifested  itself  for  between  ten  and 
twenty  minutes,  with  the  corresponding  vessels  of  a  living  rabbit,  so  as  to  re-es- 
tablish the  circulation  in  the  lower  extremities,  the  rigidity  disappeared  in  from 
six  to  ten  minutes,  and  in  two  or  three  minutes  afterwards  the  muscles  contracted 
on  being  stimulated.  He  has  subsequently  made  similar  experiments  upon  the 
muscles  of  a  decapitated  criminal;  the  hand  being  selected  as  a  convenient  part 
for  the  purpose.  It  was  not  until  nearly  12  J  hours  after  death,  that  all  traces 
of  irritability  had  left  the  muscles;  and  the  injection  was  not  commenced  until 
45  minutes  after  this,  cadaveric  rigidity  having  appeared  in  the  interval.  About 
half  a  pound  of  human  blood,  which  had  been  defibrinated  and  freely  exposed 
to  the  air  so  as  to  acquire  the  arterial  tint,  was  then  injected  at  intervals  for 
about  thirty-five  minutes;  ten  minutes  after  the  last  injection,  the  greater  number 
of  the  muscles  were  found  to  be  irritable ;  and  these  remained  so  for  two  hours, 
after  which  the  contractility  gradually  departed,  and  was  succeeded  by  cadaveric 
rigidity.  The  blood  which  had  been  injected  in  an  arterialized  condition,  issued 
from  the  vessels  quite  dark ;  and  as  this  occurred  over  and  over  again,  the  change 
of  hue  could  not  be  attributed  to  anything  else  than  the  reaction  between  the 
blood  and  the  tissues. — Similar  experiments  were  made  27  hours  after  death, 
upon  the  muscles  of  the  foot  of  the  same  criminal;  but  with  an  entirely  nega- 
tive result,  save  that  the  blood  which  was  injected  returned  of  a  considerably 
darker  hue.1 

324.  The  influence  of  supply  of  Arterial  blood  upon  the  Muscles  is  twofold ; 
it  affords  the  materials  for  the  nutrition  of  the  tissue; — and  it  furnishes  (what 
is  perhaps  more  immediately  necessary)  the  supply  of  oxygen  required  for  that 
metamorphosis  of  the  tissue,  which  seems  to  be  an  essential  condition  of  the 
generation  of  its  contractile  force.  As  this  oxygen  is  taken  in  through  the 
lungs,  and  as  the  greater  part  of  it  is  thrown  off  (when  united  with  carbon  into 
carbonic  acid)  by  the  same  channel,  we  should  expect  to  find  a  very  close  corre- 
spondence between  the  amount  of  muscular  power  developed  in  an  animal,  and 
the  quantity  of  oxygen  consumed  in  its  respiration;  and  this  is  in  reality  the 
case.  We  find,  for  example,  that  in  Birds  and  Insects,  whose  respiration  is  the 
highest,  the  muscular  power  is  greater  in  proportion  to  their  size,  than  in  any 
other  animals.  In  the  Mammalia  and  certain  Fishes,  that  might  be  almost 
called  warm-blooded,  it  is  only  in  a  degree  inferior.  But  in  the  cold-blooded 
Reptiles,  Fishes,  and  Mollusca,  the  muscular  power  is  comparatively  feeble; 
though  even  here  we  trace  gradations,  which  accord  well  with  the  relative  quan- 
tities of  oxygen  consumed.  But  in  proportion  to  the  feebleness  of  the  power, 
do  we  usually  find  its  duration  greater  (§  319);  so  that  it  is  not  so  immediately 
dependent  upon  the  supply  of  oxygen,  in  cold-blooded,  as  in  warm-blooded  ani- 
mals. Thus,  it  is  found  that  Frogs  are  still  capable  of  voluntary  movement  after 
the  heart  has  been  cut  out,  and  can  move  limbs  which  are  connected  with  the 
trunk  by  the  nerves  alone;  and  that  this  power  is  not  altogether  due  to  the 
blood  which  may  remain  in  the  capillary  vessels,  is  shown  by  the  experiment  of 
Miiller,  who  found  the  muscles  still  contractile,  after  he  had  expelled  all  the 
blood,  by  forcing  a  current  of  water  into  an  artery,  until  it  escaped  from  the 
divided  veins. — It  seems  probable  that  the  Muscles  of  Organic  life  are  less  imme- 
diately dependent  upon  a  supply  of  arterialized  blood,  than  are  those  of  Animal 

1  "Gazette  Medicale,"  1851,  Nos.  24,  27. 


324  OP   THE   PRIMARY   TISSUES   OF   THE    HUMAN    BODY. 

life ;  for  the  Heart  will  continue  to  contract,  when  the  blood  in  its  vessels  is 
entirely  venous,  and  when  the  circulation  in  it  has  come  to  a  stand.  Still,  the 
dependence  of  its  action  upon  a  constant  supply  of  arterial  blood,  is  very  close ; 
and  in  all  animals,  however  different  the  plans  of  their  circulation,  we  find  a 
provision  for  this  supply,  by  a  special  arrangement  of  the  coronary  arteries. 
That  the  heart's  action  comes  to  an  end  much  sooner,  after  the  destruction  of 
animal  life  by  pithing,  when  the  coronary  arteries  have  been  tied,  than  when 
they  are  left  untouched,  has  been  proved  by  the  experiments  of  Mr.  Erichsen.1 
In  an  animal  that  has  been  pithed,  but  whose  heart  has  been  left  intact,  artificial 
respiration  will  easily  keep  up  its  action  for  an  hour,  or  an  hour  and  a  half. 
But  when  the  coronary  arteries  were  tied,  a  mean  of  six  experiments  gave  a 
duration,  for  the  ventricular  action,  of  only  23  J  minutes  after  the  ligatures  were 
applied,  and  32 £  minutes  after  the  pithing;  and  in  no  instance  was  it  prolonged 
more  than  31  minutes  after  the  application  of  the  ligature,  or  37  minutes  after 
the  pithing.  On  the  other  hand,  when  the  aorta  was  tied,  so  that  the  coronary 
arteries  were  distended  with  blood,  the  circulation  being  carried  on  through  them 
alone,  the  right  ventricle  continued  to  act  up  to  the  82d  minute. 

325.  It  has  been  maintained  by  many  Physiologists,  that  the  Irritability  of 
Muscle  is  dependent  upon  the  Nervous  system ;  and  the  loss  of  that  irritability 
which  usually  follows  division  of  the  nerves  of  a  voluntary  muscle  at  no  distant 
date,  is  continually  cited  as  a  proof  of  this  dependence.     Two  views  of  this  sub- 
ject have  been  advanced,  both  of  which  demand  some  notice,  on  account  of  the 
eminence  of  the  authorities  by  which  they  have  been  respectively  sustained. 
The  first  of  these  is,  that  Muscular  irritability  is  derived  from  some  influence  or 
energy  communicated  from  the  Brain  or  Spinal  Cord,  or  that  these  organs  supply 
some  condition  essential  to  its  exercise ;  a  doctrine  of  which,  at  the  present  time, 
Prof.  Miiller  and  Dr.  M.  Hall  may  be  regarded  as  the  principal  supporters. 
The  opinion  that  contractility  cannot  be  an  independent  endowment  of  an  organ- 
ized structure,  is  at  once  negatived  by  the  fact  that,  in  Plants,  we  find  tissues 
endowed  with  a  high  degree  of  contractility,  and  manifesting  this  property, 
without'  any  possible  intervention  of  a  nervous  system,  on  the  application  of 
stimuli  to  themselves.     In  the  lower  classes  of  animals,  too,  there  is  good  reason 
to  believe  that  contractility  is  more  widely  diffused  through  their  tissues,  than 
nervous  agency  can  be ;  and  we  shall  see  that  rhythmical  contractions  take  place 
in  the  rudimentary  heart,  when  as  yet  no  nerves  or  ganglia  have  made  their 
appearance.     Again,  the  action  of  the  heart  may  be  kept  up,  in  the  highest 
Animals,  by  taking  care  that  the  current  of  the  circulation  be  not  interrupted, 
for  a  long  time  after  the  removal  of  the  brain  and  spinal  cord ;   it  may  even 
continue  when  completely  separated  from  the  body,  which  shows  that  the  great 
centres  of  the  ganglionic  system  cannot  supply  any  influence  necessary  to  it; 
and  there  are  many  instances,  in  which  the  Human  foetus  has  come  to  its  full 
size,  so  that  its  heart  must  have  regularly  acted,  without  the  existence  of  a  brain 
or  spinal  cord.     Further,  the  irritability  of  muscles  of  the  first  class  continues 
for  a  long  time  after  their  nerves  are  divided ;  and  may  be  called  into  action  by 
stimuli  directly  applied  to  the  parts  themselves,  or  to  their  nerves  below  the 
section,  so  long  as  their  nutrition  is  unimpaired. — The  loss  of  the  irritability  of 
Muscles,  within  a  few  weeks  after  the  section  of  their  nerves,  is  clearly  due  to 
the  alteration  in  their  nutrition,  consequent  upon  their  disuse  (§  313).     This 
has  been  proved  to  demonstration  by  the  very  ingenious  experiments  of  Dr.  J. 
Reid.3     "The  spinal  nerves  were  cut  across,  as  they  lie  in  the  lower  part  of  the 
spinal  canal,  in  four  frogs;  and  both  posterior  extremities  were  thus  insulated 

1  "Medical  Gazette,"  July  8,  1842. 

8  "Edinburgh  Monthly  Journal  of  Medical  Science,"  May,  1841 ;  and  "Physiological, 
Anatomical,  and  Pathological  Researches,"  p.  11. 


FUNCTIONS   OF   MUSCULAR   TISSUE.  325 

from  their  nervous  connections  with  the  spinal  cord.  The  muscles  of  one  of 
the  paralyzed  limbs  were  daily  exercised  by  a  weak  galvanic  battery;  while 
those  of  the  other  limb  were  allowed  to  remain  quiescent.  This  was  continued 
for  two  months;  and  at  the  end  of  that  time,  the  muscles  of  the  exercised  limb 
retained  their  original  size  and  firmness,  and  contracted  vigorously,  while  those 
of  the  quiescent  limb  had  shrunk  to  at  least  one-half  of  their  former  bulk,  and 
presented  a  marked  contrast  with  those  of  the  exercised  limb.  The  muscles  of 
the  quiescent  limb  still  retained  their  contractility,  even  at  the  end  of  two  months; 
but  there  can  be  little  doubt  that,  from  their  imperfect  nutrition,  and  the  pro- 
gressing changes  in  their  physical  structure,  this  would  in  no  long  time  have 
disappeared,  had  circumstances  permitted  the  prolongation  of  the  experiment."1 
This  experiment  satisfactorily  explains  the  fact  observed  by  Dr.  M.  Hall, 
that,  in  cases  in  which  the  cause  of  the  paralysis  is  situated  in  the  Brain,  and  in 
which  the  Spinal  Cord  and  its  nerves  are  unaffected,  the  irritability  of  the  mus- 
cles of  the  paralyzed  part  is  not  destroyed,  even  after  a  considerable  lapse  of  time. 
For,  if  the  capability  of  performing  reflex  actions  still  exist,  on  the  part  of  the  nerv- 
ous system,  it  is  manifest  that  the  muscles  will  be  occasionally  excited  to  action 
through  this  channel;  and  that  their  nutrition  and  vital  properties  will  thereby 
be  preserved,  as  they  were  in  Dr.  Reid's  experiments,  by  the  artificial  excitement 
of  galvanism. — Another  equally  satisfactory  proof  that  the  loss  of  Irritability, 
which  follows  the  severance  of  the  connection  between  the  Nervous  centres  and 
the  Muscle,  is  not  immediately  due  to  the  interruption  of  any  influence  communi- 
cated by  the  former,  has  been  given  by  the  experiments  of  Dr.  J.  Ileid  (loc. 
cit.);  who  found  that,  if  the  irritability  of  Muscles  be  exhausted  by  means  which 
have  no  tendency  to  impair  their  healthy  nutrition,  and  the  other  conditions 
favor  the  normal  performance  of  the  nutrient  processes,  the  irritability  is  restored, 
and  remains  for  some  time.  His  first  experiments  were  on  cold-blooded  animals, 
and  they  would  in  themselves  be  sufficiently  satisfactory ;  but  in  the  Rabbit  their 
subsequent  repetition  established  the  fact  beyond  all  doubt.  "  The  sciatic  nerve 
was  divided  in  the  Rabbit,  and  a  portion  of  it  removed.  One  wire  from  two 
galvanic  batteries  consisting  of  thirty  pairs  of  plates,  was  applied  over  the  course 
of  the  nerve ;  and  the  other  wire  was  applied  over  the  foot,  which  was  kept  moist 
until  the  muscles  had  ceased  to  contract.  Three  days  after  this,  a  weaker  battery 
was  used,  and  the  muscles  of  the  limb  had  recovered  their  contractility,  and 
contracted  powerfully.  The  more  powerful  battery  was  used  as  before,  until 
the  muscles  had  ceased  to  respond  to  the  excitement;  and  three  days  after  this, 
they  had  again  recovered  their  contractility."  It  seems  scarcely  possible  to 
draw  any  other  inference  from  these,  experiments,  than  that  Irritability  is  a  pro- 
perty inherent  in  Muscular  tissue,  and  that  the  agency  of  the  Nervous  system 
upon  it  is  merely  to  call  it  into  active  operation. 

326.  The  second  doctrine  referred  to,  as  having  been  taught  by  some  Physi- 
ologists, is,  that  Muscles,  though  not  dependent  on  Nerves  for  their  peculiar 
vital  power,  are  yet  dependent  upon  them  for  the  exercise  of  that  power;  all 
stimuli,  which  excite  muscles  to  contraction,  operating  first  on  the  nervous  fila- 
ments which  enter  muscles,  and  through  them  on  the  muscular  fibres. — The  facts 
which  have  been  already  stated,  in  regard  to  the  ordinary  action  of  the  Muscles 
of  Organic  life,  furnish  a  sufficient  answer  to  this  hypothesis.  It  is  with  great 

1  A  fact  of  an  exactly  parallel  character  has  fallen  under  the  Author's  observation,  in 
a  case  of  Hysteric  Paraplegia,  in  which  one  leg  was  occasionally  affected  with  severe 
cramps.  The  muscles  of  this  leg  suffered  much  less  diminution  of  size  and  firmness  than 
those  of  the  other ;  so  that  there  was  a  difference  of  more  than  an  inch  in  the  circumference 
of  the  limbs.  But  since  the  paraplegia  has  been  recovered  from,  voluntary  power  having 
been  established  in  both  limbs,  and  the  muscles  of  both  having  been  exercised  in  the  same 
degree,  they  have  regained  their  normal  size  and  firmness,  and  there  is  no  longer  any  per- 
ceptible difference  between  them. 


326  OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 

difficulty  that  these  can  be  made  to  display  their  irritability,  by  any  stimuli 
applied  to  their  nerves ;  whilst  they  manifest  it  strongly,  when  the  stimulus  is 
directly  applied  to  themselves.  Even  in  the  Muscles  of  Animal  life,  individual 
fasciculi  may  be  thrown  into  action  in  the  same  manner;  although  the  entire 
mass  cannot  be  put  into  combined  operation,  except  by  a  stimulus  simultaneously 
communicated  to  the  whole,  which  the  nerve  affords  the  readiest  means  of  effect- 
ing. Perhaps  the  most  satisfactory  disproof  of  it,  however,  is  to  be  found  in 
the  observation  of  Mr.  Bowman  already,  cited  (§  302),  that  a  single  fibre,  com- 
pletely isolated  from  all  its  connections,  may  be  seen  with  the  microscope  to 
pass  into  a  state  of  contraction,  under  the  influence  of  direct  irritation.  Further, 
it  has  been  experimentally  ascertained,  that  there  are  some  chemical  stimuli, 
which  will  produce  the  contraction  of  muscles  when  directly  applied  to  them, 
but  of  which  the  influence  cannot  be  transmitted  through  the  nerves;  this  is 
especially  the  case  with  regard  to  acids. 

327.  When  all  these  considerations  are  allowed  their  due  weight,  we  can 
scarcely  do  otherwise  than  acquiesce  fully  in  the  doctrine  of  Haller,  which  in- 
volves no  hypothesis,  and  which  is  perfectly  conformable  to  the  analogy  of  other 
departments  of  Physiology.     He  regarded  every  part  of  the  body  which  is 
endowed  with  Irritability,  as  possessing  that  property  in  and  by  itself;  but  con- 
sidered that  the  property  is  subjected  to  excitement  and  control  from  the  Nerv- 
ous System,  the  agency  of  which  is  one  of  the  stimuli  that  can  call  it  into 
operation.     It  may  be  desirable  briefly  to  recapitulate  the  facts,  by  which  this 
doctrine  is  supported.     1.  The  existence  in  Vegetables  of  irritable  tissues, 
which  are  excited  to  contraction  by  stimuli  directly  applied  to  themselves,  and 
which  can  be  in  no  way  dependent  upon,  or  influenced  by,  a  Nervous  system. 
2.  The  existence  in  Animals  of  a  form  of  Muscular  tissue,  which  is  especially 
connected  with  the  maintenance  of  the  Organic  functions,  and  which  is  much 
more  readily  excited  to  action  by  direct  stimulation,  than  it  is  by  Nervous 
agency.     3.  The  fact  that,  by  the  agency  of  these,  the  organic  functions  may 
go  on  (so  long  as  their  other  requisite  conditions  are  supplied)  after  the  removal 
of  the  nervous  centres  (of  the  Cerebro-spinal  system  at  least)  and  when  these 
were  never  present;  rendering  it  next  to  certain,  that  their  ordinary  operations 
are  not  dependent  upon  any  stimuli  received  through  the  nerves,  but  upon  those 
directly  applied  to  themselves.     4.  The  persistence  of  irritability  in  Muscles, 
for  some  time  after  the  Nerves  have  ceased  to  be  able  to  convey  to  them  the 
effects  of  stimuli;  this  is  constantly  seen  in  regard  to  the  Sympathetic  system 
of  nerves,  and  the  muscles  of  Organic  life  upon  which  they  operate;  and  it  is 
shown,  by  the  agency  of  narcotics,  to  be  true  also  with  respect  to  the  Cerebro- 
Spinal  system  and  the  muscles  of  Animal  life.     5.  The  persistence  of  irritability 
in  the  muscles,  after  their  complete  isolation  from  the  nervous  centres,  so  long 
as  their  nutrition  is  unimpaired;  and  the  effects  of  frequent  exercise,  in  pre- 
venting the  impairment  of  the  nutrition  and  the  loss  of  irritability.     6.  The 
recovery  of  the  irritability  of  muscles,  when  isolated  from  the  nervous  centres, 
after  it  has  been  exhausted  by  repeated  stimulation;  this  also  depends  upon  the 
healthy  performance  of  the  nutritive  actions.     7.  The  contraction  of  muscular 
fibre  under  the  microscope,  when  completely  isolated  from  all  other  tissues.     In 
the  words  of  Dr.  Alison,  then,  "the  only  ascertained  final  cause  of  all  endow- 
ments bestowed  on  Nerves  in  relation  to  Muscles,  in  the  living  body,  appears  to 
be,  not  to  make  Muscles  irritable,  but  to  subject  their  irritability,  in  different 
ways,  to  the  dominion  of  the  acts  and  feelings  of  the  Mind,"  to  its  volitions, 
emotions,  and  instinctive  determinations. 

328.  Whilst  the  Irritability  of  Muscles  is  gradually  departing  after  death,  it 
not  unfrequently  shows  itself  under  a  peculiar  form ;  for  instead  of  producing  sud- 
den contractions,  speedily  followed  by  relaxation,  the  application  of  stimuli  then 
occasions  slow  and  somewhat  prolonged  contractions,  the  relaxation  after  which 


FUNCTIONS    OF    MUSCULAR   TISSUE.  327 

is  tardy.  This  form  of  contraction  is  seldom  seen  in  adult  Mammalia,  except 
(as  will  be  presently  shown)  when  death  has  taken  place  from  certain  diseases 
that  have  a  special  influence  on  the  blood  and  muscular  system;  but  it  is  stated 
by  M.  Brown-Sequard1'to  present  itself  more  constantly  in  young  animals,  and 
to  be  (so  to  speak)  an  exaggeration  of  the  ordinary  modus  operandi  of  their 
muscles,  which,  during  life,  are  much  more  slowly  thrown  into  contraction  by 
mechanical  stimuli,  than  they  are  in  adults.  The  most  remarkable  manifesta- 
tions of  it  yet  observed,  however,  have  been  witnessed  after  death  from  Cholera 
and  Yellow  Fever;  for  in  these  cases,  the  muscular  contractions,  though  capable 
of  being  excited  by  mechanical  stimulation  applied  to  the  muscles  themselves, 
are  frequently  spontaneous,  and  sometimes  give  rise  to  movements  strongly  re- 
sembling the  ordinary  actions  of  the  living  state.  Thus,  in  one  case,  about  ten 
minutes  after  the  cessation  of  the  respiration  and  circulation,  Mr.  N.  B.  Ward 
saw  the  eyes  open,  and  move  slowly  in  a  downward  direction ;  this  was  followed, 
a  minute  or  two  subsequently,  by  the  movement  of  the  right  arm  (previously 
lying  by  the  side)'  across  the  chest ;  there  was  also  a  slight  movement  of  the 
right  leg;  and  these  movements  of  the  limbs  (those  of  the  eyes  occurring  only 
once)  were  repeated  to  a  greater  or  less  degree  four  or  five  times,  and  fully  half 
an  hour  elapsed  before  they  entirely  ceased.  In  a  case  observed  by  Mr.  Helps, 
the  subject  of  which  was  a  man  of  remarkable  muscular  development,  the  fingers 
continually  twitched  and  trembled  after  the  respiration  had  ceased,  and  the 
fibres  of  the  muscles  were  in  a  state  of  rhythmical  motion,  so  that  when  the  fin- 
gers were  pressed  on  the  belly  of  the  biceps,  a  sensation  as  of  the  pulsation  of 
an  artery  was  plainly  felt ;  the  muscles  of  the  arm  acted  forcibly  on  even  slight 
irritation,  the  forearm  being  powerfully  flexed  when  the  biceps  was  struck  with 
the  side  of  the  hand,  and  the  fist  being  doubled  or  the  hand  extended,  according 
as  the  flexors  or  extensors  on  the  forearm  were  irritated  in  the  same  manner. 
Various  other  muscles  were  acted  on,  with  the  same  results;  and  it  was  noticed 
in  this  case  that  the  longer  the  muscles  were  allowed  to  remain  without  irrita- 
tion, the  more  powerfully  did  they  contract  when  excited.3  In  regard  to  the 
occurrence  of  this  phenomenon  after  death  from  Yellow  Fever,  several  interest- 
ing observations  have  been  recorded  by  Dr.  Bennet  Dowler,  of  New  Orleans.3 
In  one  case,  the  subject  of  which  was  an  Irishman,  aged  twenty-eight,  the  fol- 
lowing series  of  movements  took  place  spontaneously,  not  long  after  the  cessa- 
tion of  the  respiration :  first,  the  left  hand  was  carried  by  a  regular  motion  to 
the  throat,  and  then  to  the  crown  of  the  head ;  the  right  arm  followed  the  same 
route  on  the  right  side;  the  left  arm  was  then  carried  back  to  the  throat,  and 
thence  to  the  breast,  reversing  all  its  original  motions;  and  finally  the  right 
arm  and  hand  did  exactly  the  same.  In  another  case,  that  of  a  Kentuckian, 
aged  twenty -five,  the  movements  were  only  exhibited  on  mechanical  stimulation  : 
when  the  arm  was  extended  to  an  angle  of  45°  from  the  trunk,  and  was  struck 
with  the  hand,  or  with  the  flat  side  of  a  hatchet,  the  hand  was  carried  inwards 
to  the  epigastrium ;  but  when  the  arm  was  extended  upon  the  floor,  so  as  to 
form  a  right  angle  with  the  body,  the  hand  slapped  the  mouth  and  nose.  In 
like  manner,  when  the  leg  was  hanging  down,  if  the  flexors  of  the  hamstring 
muscles  were  struck,  the  heel  was  drawn  up  against  the  buttock.  The  contrac- 
tility began  to  decline  in  the  third  hour;  and  by  the  fourth,  all  motions  of  the 
limbs  ceased,  though  the  pectoral  muscles  assumed  the  ridgy  or  lumpy  form 
when  percussed.  Five  hours  after  death,  the  contractility  had  ceased,  and 

1  "Gazette  Medicale,"  Dec.  22,  1849. 

2  See  Mr.  Fredk.  Barlow's  "  Observations  on  the  Muscular  Contractions  which  occasion- 
ally occur  after  Death  from  Cholera,"  in  the  "Medical  Gazette"  for  Nov.  9,  1849,  and  Feb. 
1,  1850. 

3  "Experimental  Researches  on  the  Post-Mortem  Contractility  of  the  Muscles,"  re- 
printed from  the  "New  York  Journal  of  Medicine,"  1846. 


328  OP   THE   PRIMARY   TISSUES    OF   THE    HUMAN   BODY. 

rigidity  had  supervened.  Many  circumstances  indicate  that  these  movements 
were  due  to  the  inherent  contractility  of  the  muscles,  and  were  not  in  any  de- 
gree dependent  upon  the  operation  of  the  nervous  system;  and  Dr.  Dowler 
proved  experimentally,  by  completely  separating  limbs  which  exhibited  these 
movements,  from  the  trunk  of  the  body,  that  the  influence  of  the  nervous  cen- 
tres was  not  in  any  degree  essential  to  their  production.1  A  phenomenon  of  a 
similar  order  has  been  observed  by  Dr.  Stokes,3  even  during  the  life  of  the  sub- 
ject. In  various  cases  of  phthisis  and  of  other  exhausting  diseases,  a  sharp  tap 
with  the  fingers  on  any  muscular  part  is  instantly  followed  by  a  contraction  of 
the  part  which  receives  the  irritation,  evidenced  by  the  rise  of  a  defined  firm 
swelling,  which  is  often  so  prominent  as  to  throw  a  shadow  along  the  skin,  and 
which  endures  for  several  seconds  before  it  gradually  subsides.  The  complete 
limitation  of  this  contraction  to  the  part  struck,  is  sufficient  evidence  that  it 
must  be  attributed  to  direct  stimulation  of  the  muscle  itself,  and  not  to  a 
"  reflex"  action  of  the  nervous  system. 

329.  A  curious  question  has  been  lately  raised,  the  decision  on  which  is  of 
some  importance  in  our  determination  of  the  nature  of  the  force,  by  which  the 
contraction  of  muscles  is  occasioned.  This  is — whether  the  power  of  a  muscle 
is  greater  or  less  at  different  degrees  of  contraction,  the  same  stimulus  being 
applied.  This  seems  to  have  been  determined  by  the  ingeniously-devised  experi- 
ments of  Schwann.3  He  contrived  an  apparatus,  which  should  accurately 
measure  the  length  of  the  muscle,  and,  at  the  same  time,  the  weight  which  it 
would  balance  by  its  contraction.  Having  caused  the  muscle  of  a  Frog  to 
shorten  to  its  extreme  point,  by  the  stimulus  of  galvanism  applied  to  the  nerve, 
so  that  no  further  stimulation  could  lift  a  weight  placed  in  the  opposite  scale, 
he  allowed  the  muscle  to  relax  until  it  was  extended  to  a  certain  point,  and  then 
ascertained  the  weight  which  would  balance  its  power.  The  same  was  several 
times  repeated,  as  in  the  following  manner :  The  length  of  the  muscle  in  its 
extreme  state  of  contraction,  at  which  no  additional  force  could  be  exerted  by 
it,  being  represented  by  14,  it  was  found  that,  when  it  had  been  extended  to  17, 
it  would  balance  a  weight  of  60;  when  its  length  increased  to  19.6,  it  would 
balance  a  weight  of  120;  and  at  22.5,  it  would  balance  180.  In  another  ex- 
periment, the  muscle  at  13.5,  balanced  0;  at  18.8,  it  balanced  100;  and  at 
23.4,  it  balanced  200.  Hence  it  appears  that  a  uniform  increase  of  force  corre- 
sponds with  a  nearly  uniform  increase  in  the  length  of  the  muscle ;  or  in  other 
words,  that  when  the  muscle  is  nearly  at  its  full  length,  its  contractile  power  is 
the  greatest.  In  later  experiments  upon  the  same  muscle,  this  uniform  ratio 
seemed  to  be  departed  from ;  but,  by  comparing  the  results  in  a  considerable 
number  of  instances,  it  was  constantly  found  that,  in  those  experiments  which 
were  performed  the  soonest  after  the  preparation  of  the  frog,  and  in  which, 
therefore,  the  normal  conditions  of  the  system  were  the  least  disturbed,  the 
ratio  was  very  closely  maintained.  It  has  been  ascertained  by  Valentin,  on 
repeating  these  experiments,  that,  by  repeated  equal  irritations,  the  strength  of 
the  muscles  in  decapitated  frogs  decreases  in  a  regular  and  corresponding  ratio; 
losing  the  same  amount  in  each  successive  period  of  time.  He  also  found  that, 

1  It  is  remarkable  that,  in  the  case  of  both  these  diseases,  the  temperature  of  the  corpse 
usually  rises  considerably  after  death,  so  as  to  approach  its  usual  standard  when  the  body 
has  been  previously  cooled  down  much  below  it,  and  to  rise  considerably  higher  when 
there  has  been  no  previous  depression  (CHAP.  xin.).     Moreover,  the  cadaveric  rigidity  is 
usually  long  in  coming  on ;   being  sometimes  postponed  for  many  days  after  death  from 
Cholera. 

2  "On  Diseases  of  the  Chest,"  p.  397. 

3  Muller's  "Elements  of  Physiology,"  translated  by  Baly,  p.  903. 


FUNCTIONS   OF   MUSCULAR   TISSUE.  329 

when  all  the  Irritability  has  ceased,  the  muscles  tear  with  a  far  less  weight 
than  they  were  previously  able,  when  galvanized,  to  draw.1 

330.  It  appears  from  the  researches  of  MM.  Becquerel  and  Breschet,3  that 
Muscular  contraction  is  attended  with  a  disengagement  of  Heat.  By  careful 
experiments,  conducted  with  the  aid  of  the  "  thermo-multiplier,"  they  ascertained 
that  the  temperature  of  a  large  muscle,  such  as  the  Biceps,  uses  as  much  as  1° 
(Fahr.)  when  it  is  thrown  into  vigorous  contraction;  and  that  repeated  move- 
ments of  any  one  kind  (as  in  the  act  of  sawing)  increases  the  temperature  of  the 
muscles  which  execute  them  as  much  as  2°.  This  development  of  Heat  may 
be  attributed  with  probability  to  the  chemical  changes  which  take  place  in  the 
Muscular  substance,  when  it  is  in  a  state  of  functional  activity  (§  311);  or  it 
may  be  occasioned  by  the  friction  of  its  parts,  upon  one  another;  or  we  may 
consider  that,  like  Motion,  it  is  a  direct  result  of  the  metamorphosis  of  the  force 
which  was  previously  operative  in  the  vital  actions  of  Development  and  Nutri- 
tion.3 It  has  been  many  times  affirmed,  but  as  frequently  denied,  that  Elec- 
tricity is  developed  during  Muscular  contraction.  The  recent  researches  of  Prof. 
Matteucci  upon  the  cause  of  the  phenomenon  which  he  terms  "  induced  contrac- 
tion," have  led  him  to  an  affirmative  conclusion  upon  this  important  point.  This 
"  induced  contraction"  takes  place  in  the  muscles  of  a  prepared  "  galvanoscopic 
frog,"4  when  its  nerve  is  laid  upon  the  muscles  of  another  frog,  which  are  thrown 
into  contraction  by  electrical,  mechanical,  or  any  other  stimulation  of  its  nerves. 
It  is  requisite  that  the  nerve  of  the  "  galvanoscopic"  frog  should  touch  two  dif- 
ferent points  of  the  contracting  muscle  or  limb  of  the  entire  frog ;  just  as  it  is 
necessary  that  two  different  points  of  the  electrical  apparatus  of  the  Torpedo  or 
Grymnotus  should  be  touched  at  once,  in  order  to  obtain  manifestations  of  elec- 
tricity. Prof.  Matteucci  has  not  succeeded  in  obtaining  proof  of  electric  dis- 
turbance in  contracting  muscles,  by  any  other  means  than  the  use  of  the  "  gal- 
van  oscopic"  frog ;  the  most  delicate  galvanometer  not  affording  unexceptionable 
indications  of  it.5  But  he  considers  that  the  phenomena  of  "induced  contrac- 

1  It  has  been  inferred  by  M filler,  from  Schwann's  experiments,  that  the  power  which 
causes  the  contraction  of  a  Muscle  must  be  very  different  in  its  character  from  any  of  the 
forces  of  attraction  known  to  us ;  since  these  all  increase  in  energy  as  the  attracted  parts 
approach  each  other,  in  the  inverse  ratio  of  the  square  of  the  distance ;  so  that  the  power 
of  a  Muscle,  if  operated  on  by  any  of  these,  ought  to  increase,  instead  of  regularly  di- 
minishing, with  its  degree  of  contraction.     But  it  is' to  be  remembered  that,  as  the  obser- 
vations of  Mr.  Bowman  have  clearly  shown,  there  must  be  a  considerable  displacement  of 
the  constituents  of  every  fibre  during  contraction  ($  302) ;  so  that  it  is  easy  to  understand 
that,  the  greater  the  contraction,  the  more  difficult  must  any  further  contraction  become. 
If,  between  a  magnet  and  a  piece  of  iron  attracted  by  it,  there  were  interposed  a  spongy 
elastic  tissue,  the  iron  would  cease  to  approach  the  magnet  at  a  point,  at  which  the  attrac- 
tion of  the  magnet  would  be  balanced  by  the  force  needed  to  compress  still  further  the  in- 
termediate substance. 

2  "Archives  du  Museum,"  torn.  ii.  p.  402. 

3  It  is  suggested  by  Nasse,  that  this  elevation  of  the  temperature  of  Muscles  in  action 
is  due  to  the  increased  afflux  of  arterial  blood,  which,  according  to  him,  is  of  higher  tem- 
perature than  venous.     But  this  position  is  by  no  means  satisfactorily  established. 

4  The  " galvanoscopic  frog,"  which  has  been  continually  employed  by  Prof.  Matteucci 
to  test  minute  electrical  disturbances  which  are  not  appreciable  by  a  galvanometer,  is 
simply  the  leg  of  a  recently-killed  frog,  with  the  crural  nerve,  dissected  out  of  the  body, 
remaining  in  connection  with  it ;  the  leg  being  enclosed  in  a  glass  tube  covered  with  an  in- 
sulating varnish,  and  the  nerve  being  allowed  to  hang  freely  from  its  open  end,  when  two 
points  of  the  nerve  are  brought  into  contact  with  any  two  substances  in  different  electrical 
states,  the  muscles  which  it  supplies  are  thrown  into  contraction. 

5  On  this  account,  Prof.  Matteucci  distrusts  the  results  which  have  been  obtained  by  M. 
Du  Bois  Reymond ;  who  affirms  that  when  the  corresponding  fingers  of  the  two  hands  are 
immersed  in  two  vessels  filled  with  salt  water,  into  which  are  plunged  two  slips  of  platina 
connected  with  the  wires  of  a  very  delicate  galvanometer,  a  very  sensible  deflection  of  the 
needle,  indicating  a  current  from  the  hand  to  the  shoulder,  is  produced  by  putting  the 
muscles  of  one  arm  in  contraction  against  each  other ;  this  deflection  being  considerably 


330  OF   THE   PRIMARY   TISSUES    OF   THE   HUMAN   BODY. 

tion,"  which  he  has  experimentally  studied  under  a  great  variety  of  conditions, 
are  sufficient  to  "  demonstrate  the  production  of  an  electrical  disequilibrium  in 
the  act  of  muscular  contraction/'1 — This  production  of  Electric  disturbance  in 
muscular  contraction  may  be  attributed  to  either  or  all  of  the  causes  which  have 
been  suggested  for  the  development  of  heat ;  but  that  it  is  specially  connected 
with  the  chemical  changes  which  then  take  place,  seems  probable  from  the  fact 
that  a  contraction  in  the  muscles  of  the  galvanoscopic  frog  is  seen,  when  its 
nerve  is  simply  introduced  into  an  incision  made  in  the  muscle  of  a  living  or  a 
recently-killed  animal,  in  such  a  manner  that  the  extremity  is  applied  to  the 
deepest  part  of  the  wound,  and  another  portion  to  its  lips  or  to  the  surface  of 
the  muscle.  As  this  contraction  takes  place  when  the  muscle  is  completely  pas- 
sive, it  is  obvious  that  the  source  of  the  electric  current  which  determines  it 
must  lie  in  the  molecular  changes  taking  place  in  the  course  of  the  nutrition  of 
the  muscle ;  and  the  explanation  of  its  constant  direction  from  the  interior  to 
the  exterior  of  the  muscle  seems  to  lie  in  the  difference  in  the  rate  of  these 
changes,  which  will  go  on  more  energetically  in  its  interior  than  they  will  do 
nearer  its  surface,  where  the  proper  muscular  fibres  are  mingled  with  a  larger  pro- 
portion of  areolar  and  tendinous  substance.3  Muscular  contraction  also  gives 
rise  to  the  production  of  Soung,  as  was  first  noticed  by  Dr.  Wollaston.3  When 
the  ear  is  applied  to  a  muscle  in  action,  a  sound  is  heard  resembling  the  distant 
rumbling  of  carriage-wheels,  or  an  exceedingly  rapid  and  faint  tremulous  vibra- 
tion, which,  when  well  marked,  has  an  almost  metallic  tone.  This  sound  may 
be  readily  made  audible  in  the  manner  suggested  by  Dr.  Wollaston ;  namely, 
by  placing  the  tip  of  the  little  finger  in  the  ear,  and  then  making  some  muscles 
contract  (as  those  of  the  ball  of  the  thumb),  whose  sound  may  be  conducted  to 
the  ear  through  the  substance  of  the  hand  and  finger.  The  continuity  of  this 
sound  through  the  whole  period  during  which  contraction  is  maintained,  is  an 
important  confirmation  of  the  view  which  is  based  on  other  foundations,  that 
there  is  a  continual  alternation  of  contractions  and  relaxations  among  the  indi- 
vidual fibres  of  any  Muscle  which  is  putting  forth  its  contractile  power,  as  a 
whole,  for  any  length  of  time  (§  303).  The  sound  may  be  readily  conceived 
to  depend  upon  the  friction  of  the  elements  of  the  muscle,  one  upon  another; 
which  must  thus  be  perpetually  taking  place,  so  long  as  it  continues  in  a  state 
of  activity.  There  can  be  little  question  that  the  first  sound  of  the  Heart, 
which  accompanies  the  ventricular  systole,  is  partly  attributable  to  muscular 
contraction. 

331.  Of  Muscular  Tonicity. — We  have  now  to  consider  the  other  form  of 
Contractility,  which  produces  a  constant  tendency  to  contraction  (varying,  how- 
ever, as  to  its  degree)  in  the  Muscular  fibre ;  but  which  is  so  far  different  from 
simple  Elasticity,  that  it  abates  after  death,  before  decomposition  has  taken 
place.  This  Tonicity  is  to  be  distinguished  from  the  Muscular  "  tension,"  which 
is  the  result  of  the  "reflex"  operation  of  the  nervous  centres  (CHAP.  xiv. 
SECT.  2) ;  being  manifested  as  well  when  the  muscle  is  altogether  removed  from 

increased  by  alternately  contracting  the  muscles,  first  of  one  arm,  and  then  of  the  other, 
in  time  with  the  oscillations  of  the  needle.  Nevertheless,  Prof.  Matteucci  (whose  authority 
on  this  subject  stands  most  deservedly  high),  after  pointing  out  various  sources  of  error  in 
the  use  of  the  galvanometer,  states  that  he  has  tried  a  great  number  of  experiments  after 
M.  Du  Bois  Reymond's  method,  increasing  the  number  of  elements  which  contract  at  the 
same  time  (as  by  operating  on  a  circle  of  thirty  or  forty  individuals,  who  all  contracted  the 
same  arm  at  once)  without  ever  succeeding  in  obtaining  an  evident  and  constant  develop- 
ment of  electricity  by  muscular  contraction.  (See  "Phil.  Trans.,"  1850,  p.  646.) 

1  "Philosophical  Transactions,"  1850,  p.  649.      See  also  Prof.  Matteucci's  previous 
researches  on  "induced  contraction,"  in  the  "Phil.  Trans."  for  1845  and  1847. 

2  See  Prof.  Matteucci's  "Lectures  on  the  Physical   Phenomena  of  Living  Beings," 
Lects.  ix.  and  x. 

3  "Philosophical  Transactions,"  1811. 


FUNCTIONS   OF   MUSCULAR   TISSUE.  331 

nervous  influence,  as  when  subjected  to  it;  and  being,  like  Irritability,  an  inher- 
ent property  of  the  tissue  itself,  the  presence  of  which  is  characteristic  of  its 
living  state.  It  manifests  itself  in  the  retraction  which  takes  place  in  the  ends  of 
a  living  muscle,  when  it  is  divided  (as  is  seen  in  amputation) ;  this  retraction 
being  permanent,  and  greater  than  that  of  a  dead  muscle.  But  its  effects  are 
much  more  remarkable  in  the  non-striated,  than  in  the  striated  form  of  Muscu- 
lar fibre ;  and  are  particularly  evident  in  the  contractile  coat  of  the  Arteries, 
causing  the  almost  entire  obliteration  of  their  tubes,  when  they  are  no  longer 
distended  with  blood.  The  disposition  to  tonic  contraction  is  increased  by  any 
considerable  change  of  temperature;  the  power  of  Heat  is  well  seen  in  the  follow- 
ing experiments  by  John  Hunter  :  "  As  soon  as  the  skin  could  be  removed  from 
a  sheep  that  was  newly  killed,  a  square  piece  of  muscle  was  cut  off,  which  was 
afterwards  divided  into  three  pieces,  in  the  direction  of  the  fibres ;  each  piece 
was  put  into  a  basin  of  water,  the  water  in  each  basin  being  of  different  tem- 
peratures, viz.,  one  about  125°,  about  27°  warmer  than  the  animal ;  another 
98°,  the  heat  of  the  animal;  and  the  third  55°,  about  43°  colder  than  the  ani- 
mal. The  muscle  in  the  water  heated  to  125°  contracted  directly,  so  as  to  be 
half  an  inch  shorter  than  the  other  two,  and  was  hard  and  stiff.  The  muscle 
in  the  water  heated  to  98°  after  six  minutes  began  to  contract  and  grow  stiff; 
and  at  the  end  of  twenty  minutes  it  was  nearly,  though  not  quite,  as  short  and 
hard  as  the  above.  The  muscle  in  the  water  heated  to  55°,  after  fifteen  minutes, 
began  to  shorten  and  grow  hard;  after  twenty  minutes  it  was  nearly  as  short  and 
as  hard  as  that  in  the  water  heated  to  98°.  At  the  end  of  twenty-four  hours, 
they  were  all  found  to  be  of  the  same  length  and  stiffness."1  The  agency  of 
Heat  in  producing  this  contraction  is  also  remarkably  shown  in  the  fact,  that  if 
a  Frog  be  immersed  in  water  of  the  temperature  of  110°,  the  muscles  of  its 
body  and  limbs  will  be  thrown  into  a  state  of  permanent  and  rigid  contraction. 
— But  it  would  seem  that  these  effects  are  chiefly,  if  not  entirely,  exerted  upon 
the  striated  form  of  Muscular  fibre ;  and  that  the  tonicity  of  the  non-striated  fibre 
is  called  into  play  by  Cold,  rather  than  by  heat.  For  if  a  Tadpole  or  Frog  be 
immersed  in  water,  the  temperature  of  which  is  gradually  raised,  until  this  state 
of  contraction  comes  on,  the  Heart  will  be  found  to  continue  pulsating  for  many 
hours  afterwards,  not  being  affected  by  the  heat.  On  the  other  hand,  if  an 
artery  in  a  living  warm-blooded  animal  be  exposed  to  cold  air  for  some  time,  the 
lowering  of  its  temperature  occasions  its  contraction  to  such  an  extent,  that  its 
cavity  becomes  almost  obliterated.  The  influence  of  warmth  in  diminishing, 
and  of  cold  in  increasing,  the  tonic  contraction  of  the  Arterial  system,  will  be 
'adverted  to  hereafter  (CHAP.  ix.  SECT.  3). 

332.  The  distinctness  of  the  Tonicity  of  Muscles  from  their  Irritability,  is 
further  shown  by  the  fact,  that  the  former  commonly  survives  the  latter;  and 
that  it  is  not  destroyed  by  treatment  which  occasions  the  complete  departure  of 
the  Irritability.  The  first  of  these  statements  finds  its  proof  in  the  phenomena 
of  "  cadaveric  rigidity"  to  be  presently  adverted  to.  Of  the  latter,  the  follow- 
ing remarkable  experiment  by  John  Hunter  is  an  ample  demonstration  :  "  From 
a  straight  muscle  in  a  bullock's  neck,  a  portion,  three  inches  in  length,  was 
taken  out  immediately  after  the  animal  had  been  knocked  down,  and  was  ex- 
posed between  two  pieces  of  lead,  to  a  cold  below  0°,  for  fourteen  minutes ;  at 
the  end  of  this  time  it  was  found  to  be  frozen  exceedingly  hard,  was  become 
white,  and  was  now  only  two  inches  long  :  it  was  thawed  gradually,  and  in  about 
six  hours  after  thawing  it  contracted  so  as  only  to  measure  one  inch  in  length ; 
but  irritation  did  not  produce  any  sensible  motion  in  the  fibres.  Here,  then, 
were  the  juices  of  muscles  frozen,  so  as  to  prevent  all  power  of  contraction  in 

1  "  General  Principles  of  the  Blood,"  in  "  Hunter's  Works,"  (Palmer's  Edition,)  vol.  iii. 
p.  110. 


I 

332  OF   THE  PRIMARY   TISSUES    OF   THE    HUMAN   BODY. 

their  fibres,  without  destroying  their  life ;  for  when  thawed  they  showed  the 
same  life  which  they  had  before  :  this  is  exactly  similar  to  the  freezing  of  blood 
too  fast  for  its  coagulation,  which,  when  thawed,  does  afterwards  coagulate,  as 
it  depends  in  each  on  the  life  of  the  part  not  being  destroyed."1 

333.  The  Rigor  Mortis,  or  cadaveric  stiffening  of  the  muscles,  is  probably  to 
be  regarded  as  the  final  manifestation  of  this  property ;  occurring  after  all  the 
Irritability  of  the  muscles  has  departed,  but  before  any  putrefactive  change  has 
commenced.  The  supervention  of  the  rigidity  is  not  usually  prolonged  much 
beyond  seven  hours ;  but  twenty  or  even  thirty  hours  may  elapse,  before  it  shows 
itself.  Its  general  duration  is  from  twenty-four  to  thirty-six  hours ;  but  it  may 
pass  off  much  more  rapidly ;  or  it  may  be  prolonged  through  several  days.  •  It 
first  affects  the  neck  and  lower  jaw,  and  seems  gradually  to  travel  downwards ; 
but,  according  to  some  observers,  the  lower  extremities  are  stiffened  before  the 
upper.  In  its  departure,  which  is  immediately  followed  by  decomposition,  the 
same  order  is  observed.  It  affects  all  the  muscles  nearly  alike ;  but  the  flexors 
are  usually  more  contracted  than  the  extensors,  so  that  the  fingers  are  somewhat 
flexed  on  the  palm,  and  the  forearm  on  the  arm ;  and  the  lower  jaw,  if  previ- 
ously drooping,  is  commonly  drawn  firmly  against  the  upper.  It  is  remarkable 
that  it  is  equally  intense  in  muscles  which  have  been  paralyzed  by  Hemiplegia, 
provided  that  no  considerable  change  has  taken  place  in  their  nutrition.  When 
very  strong,  it  renders  the  muscles  prominent,  as  in  voluntary  contraction. — 
An  attempt  has  been  made  to  connect  it  with  the  lowering  of  the  Temperature 
of  the  dead  body ;  but  with  this  it  does  not  seem  to  have  any  relation,  since  it 
has  frequently  been  observed  to  commence  long  before  the  heat  has  entirely 
departed  from  the  body,  and  appears  first  upon  the  trunk,  which  is  the  region 
last  deserted  by  warmth.  Another  attempt  has  been  made  to  show  a  correspond- 
ence between  the  Rigor  Mortis  and  the  Coagulation  of  the  Blood  in  the  vessels ; 
and  there  is  certainly  evidence  enough  to  make  it  appear,  that  some  analogy 
exists  between  these  two  actions,  though  they  are  far  from  being  identical. 
After  those  forms  of  death,  in  which  the  blood  does  not  coagulate,  or  coagulates 
feebly,  the  rigidity  commonly  manifests  itself  least ;  but  this  is  by  no  means  an 
invariable  rule.  It  seems  probable  that,  as  the  coagulation  of  the  blood  is  the 
last  act  of  its  vitality  (§  29),  so  the  stiffening  of  the  muscles  is  the  expiring 
effort  of  theirs.3 

1  "General  Principles  of  the  Blood,"  in  "  Hunter's  Works,"  (Palmer's  Edition,)  vol.  iii. 
p.  109. 

2  It  is  necessary  to  bear  in  mind,  when  the  phenomena  of  Cadaveric  Rigidity  are  brought' 
into  question  in  juridical  investigations,  that  a  state  at  first  sight  corresponding  to  it  may 
supervene  immediately  upon  death,  from  some  peculiar  condition  of  the  nervous  and  mus- 
cular systems  at  the  moment.     This  has  been  observed  in  some  cases  of  Asphyxia ;  but 
chiefly  when  death  has  resulted  from  apoplexy  following  chronic  ramollissement  of  the  brain 
or  spinal  cord.     This  contraction,  which  is  obviously  of  a  tetanic  character,  ceases  after  a 
few  hours  ;  and  is  then  succeeded  by  a  state  of  flexibility,  after  which  the  ordinary  rigidity 
supervenes. — The  following  case  illustrates  the  nature  of  the  inquiries,  to  which  this  con- 
dition may  give  rise.     The  body  of  a  man  was  found  in  a  ditch,  with  the  trunk  and  limbs 
in  such  a  relative  position,  as  could  only  be  maintained  by  the  stiffness  of  the  articulations. 
This  stiifness  must  have  come  on  at  the  very  moment  when  the  body  took  that  position ; 
unless  it  could  be  imagined,  that  the  body  had  been  supported  by  the  alleged  murderers, 
until  the  joints  were  locked  by  cadaveric  stiifness.     A  post-mortem  examination  showed 
that  there  was  no  necessity  for  this  supposition — obviously  a  very  improbable  one  in  itself — 
by  affording  sufficient  evidence  that  apoplexy,  resulting  from  the  chronic  disease,  was  the 
cause  of  death.     A  case  occurred  a  few  years  since  in  Scotland,  in  which  the  same  pica 
was  raised.     The  body  was  found  in  a  position,  in  which  it  could  have  only  been  retained 
by  rigidity  of  the  joints ;  and  it  was  pleaded  on  the  part  of  the  prisoner,  that  death  had 
been  natural,  and  had  resulted  from  fracture  of  the  processus  dentatus,  causing  sudden 
pressure  upon  the  spinal  cord,  whence  the  spasmodic  rigidity  would  naturally  result.    Proof 
was  deficient,  however,  as  to  the  existence  of  this  lesion  before  death ;  and  the  position  of 
the  body  rather  resembled  that  into  which  it  might  have  been  forced  during  the  rigidity, 


FUNCTIONS    OF    MUSCULAR   TISSUE.  333 

334.  This  phenomenon  is  rarely  absent ;  though  it  may  be  so  slight,  and  may 
last  for  so  short  a  time,  as  to  escape  observation.  The  period  which  elapses  be- 
fore its  commencement,  is  as  variable  as  its  duration ;  and  both  appear  to  be  in  some 
degree  dependent  upon  the  vital  condition  of  the  body  at  the  time  of  death. 
When  the  fatal  termination  has  supervened  on  slow  and  wasting  disease,  occa- 
sioning great  general  depression  of  the  vital  powers,  the  rigidity  usually  develops 
itself  very  early,  and  lasts  for  a  short  time.  And  the  same  is  the  case,  when 
the  muscular  Irritability  has  been  exhausted  previously  or  subsequently  to  death, 
by  repeated  and  powerful  stimulation.  Thus  M.  Brown-Sequard,1  having  been 
desirous  of  ascertaining  the  influence  of  electricity  upon  the  development  of  the 
rigidity,  subjected  the  bodies  of  four  rabbits  of  the  same  age  and  vigor,  which 
had  been  killed  by  the  removal  of  the  heart,  to  electro-magnetic  currents  of  dif- 
ferent intensities ;  a  similar  animal,  killed  in  the  same  manner,  being  reserved 
for  comparison.  The  following  were  the  results  : — 

i.  Not  electrized.     Rigidity  came  on  in  10  hours,  and  lasted  192  hours. 
ii.  Feebly  electrized  .  .  7         "  "          144       " 

in.  Somewhat  more  electrized  .  2         "  "  72       " 

iv.  Still  more  strongly  electrized      .  1         "  "  20       " 

v.   Submitted  to  a  powerful  current  7  min.  "  25  min. 

Thus  it  appears  that  the  more  powerful  the  electric  current,  the  earlier  does 
the  rigidity  appear,  and  the  shorter  is  its  duration;  and  hence  we  can  readily 
understand  that,  when  an  animal  is  killed  by  a  stroke  of  lightning,  the  rigidity 
may  supervene  so  rapidly,  and  may  depart  again  so  early,  as  to  pass  completely 
unnoticed ;  and  we  may  even  admit  the  possibility  of  the  vitality  being  so  com- 
pletely and  immediately  destroyed,  that  the  rigidity  shall  not  occur  at  all.  M. 
Brown-Sequard  has  further  ascertained,3  that  the  application  of  the  electric  cur- 
rent previously  to  death  speedily  induces  the  rigidity,  which  on  its  departure  is 
followed  by  rapid  putrefaction.  Thus,  one  of  the  posterior  members  of  a  rabbit 
was  subjected  for  half  an  hour  to  a  powerful  electro-magnetic  current,  and  the  ani- 
mal was  soon  afterwards  killed;  in  about  two  hours  and  a  half,  cadaveric  rigidity 
had  already  commenced  in  the  electrized  limb,  while  the  other  member  was  still 
supple;  about  two  hours  afterwards,  the  rigidity  had  already  begun  to  diminish 
in  the  electrized  limb,  whilst  it  had  scarcely  commenced  in  the  other ;  at  the 
end  of  two  days,  the  electrized  limb  was  already  in  incipient  decomposition,  whilst 
the  other  was  still  rigid :  eight  days  after  death,  the  electrized  limb  was  far  ad- 
vanced in  putrefaction,  but  the  other  limb  was  still  rigid;  and  its  rigidity  con- 
tinued until  the  ninth  day,  putrefaction  not  supervening  until  the  twelth. — If 
the  irritability  be  exhausted  previously  to  death,  by  other  causes,  the  effect  is 
the  same.  Thus  it  was  affirmed  by  Hunter,  that  animals  hunted  to  death  do  not 
stiffen :  and  although  subsequent  inquiry  has  shown  that  this  statement  is  not 
precisely  correct,  yet  the  rigidity  comes  on  very  early  in  such  cases  (a  few  minutes 
after  death),  and  lasts  but  for  a  short  time.3  So,  it  has  been  remarked  by  M. 
Brown-Sequard,  that  when  animals  die  from  the  effects  of  poisons  which  produce 
convulsions,  the  rigidity  appears  earlier  and  departs  sooner,  in  proportion  to  the 
violence  of  the  previous  convulsive  action.  The  same  is  the  case,  moreover,  in 

than  that  in  which  it  would  probably  have  been  at  the  moment  of  death.  There  were  also 
marks  of  violence,  and  many  other  suspicious  circumstances ;  but  the  prisoner  was  ac- 
quitted, chiefly  from  want  of  evidence  against  him.  What  seemed  to  indicate  that  the 
rigidity  was  of  the  ordinary  cadaveric  nature,  was,  that  there  was  no  evidence  of  the  body 
having  become  flexible  and  again  stiffened ;  as  it  would  probably  have  done,  had  the  rigidity 
been  of  the  spasmodic  character.  (See  "Annales  d'Hygiene,"  torn,  vii.;  and  "Watson  on 
Homicide,"  pp.  70,  266.) 

1  "Gazette  Medicale,"  1849,  No.  45.  2  Op.  cit.,  Dec.  22,  1849. 

3  See  Mr.  Gulliver  "(0n  the  state  of  the  Blood  and  Muscles  in  Animals  killed  by  Hunt- 
ing and  Fighting,"  in  "Edinb.  Med.  and  Surg.  Journ.,"  Oct.,  1848. 


334  OF   THE   PRIMARY   TISSUES    OF   THE   HUMAN   BODY. 

some  diseases  which  powerfully  affect  the  general  vital  energy,  even  though  they 
may  not  have  been  of  long  duration ;  thus,  after  death  from  Typhus,  the  limbs 
have  been  sometimes  known  to  stiffen  within  fifteen  or  twenty  minutes.  The 
same  is  observed  in  infants  and  in  old  people.  On  the  other  hand,  where  the 
general  energy  has  been  retained  up  to  a  short  period  before  death,  the  rigidity 
is  much  later  in  coming  on,  and  lasts  longer;  this  happens,  for  example,  in 
many  cases  of  Asphyxia  and  Poisoning,  in  which  it  has  been  said  not  to  occur 
at  all. 

335.  As  the  property  of  Tonicity  manifests  itself  most  decidedly  in  the  non- 
striated  muscles  in  the  living  body,  so  do  we  find  this  post-mortem  contraction 
most  remarkable  in  them.     As  soon  as  the  muscular  walls  of  the  several  cavi- 
ties lose  their  irritability,  they  begin  to  contract  firmly  upon  their  contents,  and 
thus  become  stiff  and  firm,  though  they  were  previously  flaccid.     In  this  man- 
ner, the  ventricles  of  the  Heart,  which  are  the  first  parts  to  lose  their  irritability, 
become  rigid  and  contracted  within  an  hour  or  two  after  death;  and  usually 
remain  in  that  state  for  ten  or  twelve  hours,  sometimes  for  twenty-four  or 
thirty-six,  then  again  becoming  relaxed  and  flaccid.     This  rigid  contracted  state 
of  the  heart,  in  which  the  walls  are  thickened  and  the  cavities  diminished,  was 
formerly  supposed  to  be  a  result  of  disease,  and  was  termed  concentric  hyper- 
trophy;  but  it  is  now  known,  from  the  inquiries  of  Mr.  Paget,  to  be  the  natural 
condition  of  the  organ,  at  the  period  when  the  "  rigor  mortis"  occurs  in  it. — 
The  contraction  of  the  Arterial  tubes  is  so  great,  as  to  produce  for  the  time  a 
great  diminution  in  their  caliber;  and  this  doubtless  contributes  to  the  passage 
of  the  blood  from  the  arterial  into  the  venous  system,  which  almost  invariably 
takes  place  within  a  few  hours  after  death.     The  arteries  then  enlarge  again, 
and  become  quite  flaccid,  their  tubes  being  emptied  of  their  previous  contents ; 
and  it  was  from  this  circumstance  that  the  ancient  Physiologists  were  led  to 
imagine  that  the  arteries  are  not  destined  to  carry  blood,  but  air. — So  it  has 
been  shown  by  Prof.  Valentin,1  that  if  a  graduated  tube  be  connected  with  a 
portion  of  Intestine  taken  from  a  recently-killed  animal,  filled  with  water,  and 
tied  at  the  opposite  end,  the  water  will  rise  in  a  few  hours  to  a  considerable 
height  in  the  tube,  owing  to  the  contraction  of  the  intestinal  walls.     The  post- 
mortem contraction  of  the  parturient  uterus,  to  such  an  extent  as  to  expel  the 
foetus  of  which  the  patient  had  died  undelivered,  is  a  phenomenon  which  has 
been  several  times  recorded;  and  Dr.  Robert  Lee  has  witnessed  one  remarkable 
case,  in  which,  the  patient  having  died  suddenly  from  the  rupture  of  the  uterus 
and  escape  of  the  fostus  into  the  abdominal  cavity,  the  uterus  was  found,  when 
an  examination  was  made  twenty-four  hours  after  death,  to  be  completely  in- 
verted.3 

7.    Of  the  Nervous  Tissue. 

336.  We  have,  lastly,  to  consider  the  structure,  composition,  mode  of  growth 
and  regeneration,  and  special  vital  actions,  of  the  Nervous  tissue ;  the  one  whose 
existence  is  most  distinctive  of  the  Animal  fabric,  and  which  serves  as  the  in- 
strument of  the  operations  that  are  most  peculiar  to  it.     Wherever  a  distinct 
Nervous  System  can  be  made  out  (which  has  not  yet  been  found  possible  in  the 
lowest  of  those  beings,  which,  from  their  general  structure  and  habits  of  life, 
cannot  but  be  ranked  in  the  Animal  Kingdom),  it  is  found  to  consist  of  two 
very  different  forms  of  structure ;  the  presence  of  both  of  which,  therefore,  is 
essential  to  our  idea  of  it  as  a  whole.     We  observe,  in  the  first  place,  that  it  is 

1  "Lehrbuch  der  Physiologic,"  band  ii.  p.  36. 

2  See  Dr.  Tyler  Smith's  "Parturition,  and  the  Principles  and  Practice  of  Obstetrics," 
p.  39,  Am.  Ed. — The  Author  believes  that  Dr.  T.  Smith  was  the  first  to  attribute  this  set 
of  phenomena  to  the  cadaveric  rigidity  of  the  uterus. 


STRUCTURE   OF   NERVOUS   TISSUE. 


335 


formed  of  trunks,  which  are  distributed  to  different  parts  of  the  body,  and  espe- 
cially to  the  muscles  and  to  the  sensory  surfaces;  and  of  ganglia,  or  masses  with 
which  the  central  terminations  of  those  trunks  come  into  connection,  It  is 
easily  established  by  experiment,  that  the  trunks  themselves  have  no  power  of 
originating  changes;  and  that  they  only  serve  to  conduct  or  convey  the  influence 
of  operations,  which  take  place  at  their  central  or  their  peripheral  extremities. 
For  if  a  trunk  be  divided  in  any  part  of  its  course,  all  the  organs  to  which  the 
portion  thus  cut  off  from  the  ganglion  is  distributed,  are  completely  paralyzed ; 
that  is,  no  impression  made  upon  them  is  felt  as  a  sensation,  or  produces  any 
respondent  movement ;  and  no  motion  can  be  excited  in  them  by  any  act  of  the 
mind.  Or,  if  the  substance  of  the  ganglion  be  destroyed,  all  the  parts  which 
are  exclusively  supplied  by  nervous  trunks  proceeding  from  it,  are  in  like  man- 
ner paralyzed. — But  if,  when  a  trunk  is  divided,  the  portion  still  connected  with 
the  ganglion  be  pinched  or  otherwise  irritated,  sensations  are  felt,  which  are 
referred  to  the  points  supplied  by  the  separated  portion  of  the  trunk ;  which 
shows  that  the  part  remaining  in  connection  with  the  ganglion  is  still  capable  of 
conveying  impressions,  and  that  the  ganglion  itself  receives  these  impressions, 
and  makes  them  felt  as  sensations.  On  the  other  hand,  if  the  separated  portion 
of  the  trunk  be  irritated,  motions  are  excited  in  the  muscles  which  it  supplies ; 
showing  that  it  is  still  capable  of  conveying  the  motor  influence,  though  cut  off 
from  the  usual  source  of  that  influence. 

337.  In  the  ordinary  Nerve-trunks,  we  find  only  one  form  of  Nervous  tissue; 
that  which  may  be  designated  as  the  fibrous  or  tubular.  In  the  Ganglia,  we 
find,  in  addition  to  this,  a  substance  made  up  of  peculiar  cells  or  vesicles ;  which 
may  be  distinguished  as  the  vesicular  nervous  matter.  In  fact,  the  character  of 
a  Granglionic  centre  (which  is  frequently  not  otherwise  clearly  distinguished  as 
such)  is  derived  from  the  presence  of  this  vesicular  substance  (Fig.  105). 

Fig.  105. 


Dorsal  Ganglion  of  Sympathetic  nerve  of  Mouse:  a,  b,  cords  of  connection  with  adjacent  sympathetic  ganglia; 
c,  c,  c,  c,  branches  to  the  viscera  and  spinal  nerves ;  d,  ganglionic  globules  or  cells ;  e,  nervous  fibres  traversing 
the  ganglion. 

338.  The  ultimate  Nerve- Fibre,  in  its  most  complete  form — such  as  is  pre- 
sented to  us  in  the  ordinary  cranio-spinal  nerves — is  distinctly  tubular;  being 
composed  of  an  external  cylindrical  membranous  sheath,  within  which  the  pecu- 
liar nervous  matter  is  contained.  This  membranous  tube,  like  the  Myolemma 
of  muscular  fibre,  is  extremely  delicate  and  transparent;  and  is  nearly  or  quite 
homogeneous.  It  is  not  penetrated  by  bloodvessels;  nor  is  it  ever  seen  to  branch 
or  anastomose  with  others;  so  that  there  is  reason  to  regard  it  as  forming  one 


336 


OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 


continuous  sheath,  which  isolates  the  contained  matter  from  the  surrounding 
tissue,  along  the  whole  course  of  the  nerve-trunk,  from  its  central  to  its  peri- 
pheral extremity.  When  the  nerve-fibres  are  examined  in  a  very  fresh  state, 
their  contents  appear  pellucid  and  homogeneous,  and  of  a  fluid  consistence ;  so 
that  each  tube  or  fibre  looks  like  a  cylinder  of  clear  glass,  with  simple,  well- 
defined,  dark  edges.  But  a  kind  of  coagulation  soon  takes  place  in  the  contained 
substance,  making  it  easily  distinguishable  from  the  tube  itself;  for  the  latter  is 
then  marked  by  a  double  line,  as  shown  in  Fig.  106,  A.  The  substance  which 
is  in  immediate  contact  with  the  inner  wall  of  the  nerve-tube,  is  more  opaque 
than  that  which  occupies  its  centre,  and  of  a  different  refractive  power ;  and 
thus  it  forms  a  hollow  cylinder,  which  surrounds  the  latter,  and  which  is  knows 
under  the  name  of  the  "  white  substance  of  Schwann."  The  centre  or  axis  of 
the  tube  is  occupied  by  a  substance  that  preserves  its  transparency;  and  this  is 
the  " axis-cylinder''  of  Rosenthal  and  Purkinje,  the  "  primitive  band"  of  Remak. 
Much  discussion  has  taken  place  respecting  the  condition  under  which  this  central 
substance  exists  in  the  living  nerve-fibre ;  some  microscopists  considering  that  it 
is  then  soft  and  semi-fluid,  and  that  its  subsequent  firmness  is  derived  from  a 
kind  of  coagulation;  whilst  others  maintain  that  it  always  possesses  a  considera- 
ble degree  of  firmness  and  tenacity,  and  that  it  must  be  considered,  not  only  as 
having  a  proper  independent  existence,  but  as  being  the  essential  part  of  the 
tubular  fibre.  This  last  view  has  recently  been  strenuously  contended  for  by 
Prof.  Kolliker,1  who  maintains  that  we  do  not  distinguish  it  in  the  living  nerve- 
tube,  merely  because  it  then  possesses  the  same  refractive  power  as  the  surround- 
ing substance,  and  who  urges  the  readiness  with  which  it  may  be  brought  into 
view  by  various  reagents  (such  as  concentrated  acetic  acid,  alcohol,  ether,  iodine, 
&c.),  in  nerves  taken  directly  from  the  living  animal,  as  a  proof  of  the  distinct- 
ness of  its  character.  The  effects  of  reagents  further  lead  to  the  suspicion,  that 
the  "  axis-band"  (this  term  being  preferable  to  axis-cylinder,  since  the  substance 
seems  more  commonly  to  possess  a  flattened  than  a  cylindrical  form),  is  of  an 

Fig.  106. 


Stricture  of  Tubular  Nerve-fibres,  magnified  350  diameters :  A,  cylindrical  tubuli  from  nerve ;  B,  varicose 
tubuli  from  brain;  c,  nerve-tubes,  of  which  one  exhibits  the  remains  of  nuclei  in  its  walls. 

albuminous  nature ;  and  that  the  "white  substance  of  Schwann"  is  the  oleaginous 
constituent  of  the  nerve-fibre.  The  best  evidence  of  the  superior  consistence  of  the 
axis-band  during  life,  appears  to  the  Author  to  be  derived  from  the  distinct  con- 
tinuity which  it  may  be  not  unfrequently  seen  to  present  when  prolonged  beyond 
its  envelops  (§  343);  and  from  its  occasional  fission  into  finer  fibrilke,  the 

1  "  Mikroskopisch*  Anatomic,"  band  ii.  p.  393,  et  scq. 


STRUCTURE   OF  NERVOUS   TISSUE.  337 

tendency  to  which  subdivision  is  often  marked  by  a  longitudinal  striation.  Whilst 
this  element  of  the  nerve-fibre  is  constant,  the  "  white  substance  of  Schwann" 
is  extremely  variable  in  its  amount,  and  not  unfrequently  seems  to  be  almost 
entirely  deficient,  especially  in  the  "  varicose"  tubes,  where  it  is  only  visible  in 
the  varicosities ;  it  may  be  surmised  that  the  chief  purpose  served  by  this  sub- 
stance is  the  more  complete  isolation  of  the  "  axis-band."  The  membranous 
sheath  itself  varies  in  density  in  different  parts,  being  stronger  in  the  nervous 
trunks  than  in  the  substance  of  the  brain  and  spinal  cord.  In  the  former,  it  is 
not  difficult  to  show  that  the  regular  form  of  the  nerve-tube  is  a  perfect  cylinder; 
though  a  little  disturbance  will  cause  an  alteration  in  this — a  small  excess  of 
pressure  in  one  part  forcing  the  contents  of  the  tube  towards  another  portion, 
where  they  are  more  free  to  distend  it,  and  thus  producing  a  swelling.  The 
greater  delicacy  of  the  tubular  sheath  in  the  latter,  causes  this  result  to  take 
place  with  yet  more  readiness;  so  that  a  very  little  manipulation  exercised  upon 
the  fibres  of  the  brain  or  spinal  cord,  or  on  those  of  special  sense,  occasions  them  to 
assume  a  varicose  or  beaded  appearance  (Fig.  106,  B),  which,  when  first  observed 
by  Ehrenberg,  was  thought  to  be  characteristic  of  them.  When  the  fibres  of  these 
parts  are  examined,  however,  without  any  such  preparation,  and  especially  when 
they  are  seen  in  situ,  they  are  found  to  be  as  cylindrical  as  the  others.  The 
diameter  of  the  tubular  fibres  of  the  Cerebro-spinal  nerve-trunks  in  Man,  usually 
varies  from  about  l-2000th  to  14000th  of  an  inch ;  being  sometimes  as  great, 
however,  as  l-500th  of  an  inch,  and  sometimes  much  below  the  least  of  the  above 
dimensions.  The  fibres  decrease  in  size  as  they  approach  the  brain,  either 
directly,  or  through  the  medium  of  the  spinal  cord ;  and  in  the  brain  itself  they 
continue  to  diminish,  as  they  pass  through  the  medullary  towards  the  cortical 
portion;  so  that  they  are  very  commonly  found  of  no  more  than  l-7000th  or 
l-8000th  of  an  inch  in  diameter,  and  sometimes  as  little  as  l-14,000th.  The  Sym- 
pathetic system  contains,  with  a  few  tubular  fibres  of  the  full  size,  a  great  num- 
ber of  much  smaller  dimensions,  ranging  from  about  l-8300th  to  14500th  of 
an  inch  in  diameter,  and  not  presenting  a  distinct  double  contour,  although 
having  a  well-defined  sharp  outline.  These  were  designated  by  Bidder  and 
Volkrnann,  who  first  directed  attention  to  them,  the  "  fine"  fibres ;  but  it  is  now 
well  ascertained  that  there  is  nothing  to  distinguish  them  from  other  fibres  of 
like  dimensions  elsewhere. 

339.  Besides  these  proper  tubular  nerve-fibres — of  which,  in  combination 
with  areolar  and  fibrous  tissue,  bloodvessels,  &c.,  a  large  proportion  of  the 
Cerebro-spinal  nerve-trunks  are  made  up — there  are  certain  other  fibres,  which 
are  peculiarly  abundant  in  the  trunks  of  the  Sympathetic  system,  and  which 
are  of  different  character  from  the  preceding.  They  are  chiefly  distinguished 
by  their  small  size,  their  diameter  not  being  above  one-half  or  one-third  of  that 
of  the  ordinary  nervous  tubuli.  They  are  destitute  of  the  double  contour,  which 
has  been  shown  to  result  in  the  preceding  case  from  the  presence  of  two  distinct 
substances  within  the  tubular  investment ;  and  their  substance  appears  to  be 
homogeneous,  or  at  most  but  faintly  granular,  with  numerous  nuclear  corpuscles 
scattered  through  it,  which,  when  not  originally  visible,  are  brought  into  view 
by  the  agency  of  acetic  acid.  When  these  fibres  are  aggregated  in  bundles, 
they  possess  a  yellowish  gray  color ;  and  they  impart  somewhat  of  this  hue  to 
the  nerve-trunks  in  which  they  predominate.  Although  these  fibres,  which  are 
distinguished  as  the  "gray"  or  "gelatinous,"  exist  in  greater  proportion  in  the 
Sympathetic  system  than  in  the  Cerebro-spinal,  yet  they  are  present  in  great 
numbers  in  some  of  the  trunks  of  the  latter,  the  Olfactive  nerves  being  almost 
entirely  composed  of  fibres  presenting  their  most  essential  characters  ;*  and  they 
even  seem  to  be  frequently  continuous  with  the  ordinary  tubular  fibres,  especially 

1  See  Messrs.  Todd  and  Bowman's  "Physiological  Anatomy,"  p.  397,  Am.  Ed. 
22 


338 


OF   THE   PRIMARY   TISSUES    OF   THE    HUMAN    BODY. 


with  those  of  smallest  diameter.  They  may  be  traced  into  the  ganglia  of  the 
Sympathetic,  into  the  ganglia  on  the  posterior  roots  of  the  Spinal  nerves,  and 
even  to  the  ganglionic  matter  of  the  Brain  and  Spinal  Cord.1 

340.  The  second  primary  element  of  the  Nervous  system,  without  which  the 
fibrous  portion  would  seem  to  be  totally  inoperative,  is  composed  of  nucleated 
Cells  or  Vesicles,  containing  a  finely  granular  substance,  and  lying  somewhat 
loosely  in  the  midst  of  a  minute  plexus  of  bloodvessels.  Their  original  form 
may  be  regarded  as  globular ;  whence  they  have  been  called  ganglion-globules. 
This,  however,  is  liable  to  alteration ;  sometimes,  perhaps,  from  external  com- 
pression }  but  more  commonly  through  their  own  irregular  mode  of  growth. 
They  frequently  extend  themselves  into  long  processes,  which  may  give  them 
(according  to  the  number  thus  projecting)  a  "  caudate"  or  a  "  stellate"  form 
(Fig.  107).  These  processes  are  composed  of  a  finely-granular  substance,  re- 
Fig.  107. 


Various  forms  of  Ganglionic  Vesicles :  A,  B,  large  stellate  cells,  with  their  prolongations,  from  the  anterior 
horn  of  the  gray  matter  of  the  spinal  cord;  c,  nerve-cell  with  its  connected  fibre,  from  the  anastomosis  of  the 
facial  and  auditory  nerves  in  the  Meatus  auditorius  internus  of  the  Ox :  a,  cell-wall ;  b,  cell-contents ;  c,  pig- 
ment ;  d,  nucleus ;  e,  prolongation  forming  the  sheath  of  the  fibre ;  /,  nerve-fibre :  D,  nerve-cell  from  the  sub- 
stantia  ferruginea  of  Man :  E,  smaller  cell  from  the  Spinal  Cord.  Magnified  350  diameters. 

sembling  that  of  the  interior  of  the  vesicle,  with  which  they  seem  to  be  dis- 
tinctly continuous.  They  are  very  liable  to  break  off  near  the  vesicle;  but  if 
traced  to  a  distance,  they  are  found  to  divide  and  subdivide,  and  at  last  to 
give  off  some  extremely  fine  transparent  fibres ;  some  of  which  seem  to  inosculate 
with  those  of  other  stellate  cells,  whilst  others  become  continuous  with  the  axis- 

*  Much  controversy  has  taken  place  in  Germany,  regarding  the  existence  of  a  set  of 
fibres  peculiar  to  the  Sympathetic  system.  The  gray  or  gelatinous  fibres,  described  by 
Remak,  and  (following  him)  by  Miiller  and  others,  as  essentially  constituting  the  "  organic" 
system  of  Nerves,  have  been  affirmed  by  several  eminent  authorities  not  to  be  entitled  to 
the  designation  of  nerve-fibres  at  all,  but  to  be  a  form  of  simple  fibrous  tissue ;  and  the 
fine  tubular  fibres,  described  above,  were  considered  by  Bidder  and  Volkmann  to  be  the 
peculiar  constituents  of  the  Sympathetic  system.  Further  researches,  however,  seem  to 
have  removed  all  doubt  as  to  the  veal  nature  of  the  gelatinous  fibres;  as  their  continuity 
with  the  stellate  prolongations  of  the  ganglionic  cells,  and  with  the  tubular  fibres,  is  now 
established  by  the  concurrent  testimony  of  many  excellent  observers. — For  a  valuable 
summary  of  this  controversy,  see  Dr.  Sharpey's  Introduction  to  "  Quain's  Elements  of 
Anatomy,"  vol.  ii.  p.  177,  Am.  Ed. 


STRUCTURE   OF   NERVOUS   TISSUE.  339 

cylinders  of  tubular  fibres,  or  with  gelatinous  fibres.  Such  vesicles  are  seen 
alike  in  the  ganglionic  masses  of  the  Cerebro-spinal,  and  in  those  of  the  Sym- 
pathetic system. — Besides  the  finely-granular  substance  just  mentioned,  these 
cells  usually  contain  a  collection  of  pigment-granules,  which  especially  cluster 
round  the  nuclei,  and  give  them  a  reddish  or  yellowish-brown  color.  This  pig- 
ment seems  to  have  some  resemblance  to  the  hsematine  of  the  blood;  and  it  is 
usually,  if  not  invariably,  deficient  among  the  Invertebrata,  as  well  as  less 
abundant  in  Reptiles  and  Fishes.  The  vesicles  are  sometimes  covered  with  a 
layer  of  a  soft  granular  substance,  which  adheres  closely  to  their  exterior  and 
to  their  processes ;  this  is  the  case  in  the  outer  part  of  the  cortical  substance  of 
the  human  brain.  In  other  instances,  each  cell  is  inclosed  in  a  distinct  enve- 
lop, composed  of  smaller  cells,  closely  adherent  to  each  other  and  to  the  con- 
tained cell;  such  an  arrangement  is  common  in  the  smaller  ganglia,  and  in  the 
inner  portion  of  the  cortical  substance  of  the  brain. — The  diameter  of  the 
vesicles  is  extremely  variable,  owing  to  the  changes  of  form  above  described ; 
that  of  the  globular  cells  is  usually  between  l-300th  and  l-1250th  of  an  inch. 

341.  In  the  central  or  ganglionic  masses  of  the  Nervous  system  we  find  these 
vesicles  aggregated  together,  and  imbedded  in  a  finely  granular  matter ;  the 
whole  being  traversed  by  a  minute  plexus  of  capillary  bloodvessels.     The  entire 
substance,  made  up  of  these  distinct  elements,  is  commonly  known  as  the  cine- 
ritious  or  cortical  substance ;  being  distinguished  by  its  color,  in  Man  and  the 
higher  animals  at  least,  from  the  white  substance  composed  of  nerve-tubes,  of 
which  the  trunks  of  the  nerves,  as  well  as  a  large  part  of  the  brain  and  spinal 
cord  are  made  up ;  and  occupying  in  the  brain  a  position  external  to  the  latter, 
which  is  often  termed  the  medullary  substance.     This  position,  "however,  is 
quite  an  exceptional  one ;  for  in  the  spinal  cord  and  in  the  scattered  ganglia  of 
Vertebrated  animals,  and  in  all  the  ganglionic  centres  of  Invertebrata — every- 
where, in  fact,  except  in  the  Brain— the  vesicular  nerve-substance  occupies  the 
centres  of  the  ganglia;  consequently,  the  terms  "  cortical"  and  " medullary/'  as 
applied  to  the  vesicular  and  tubular  substances  respectively,  are  quite  inappro- 
priate.    Nor  are  the  designations  that  have  reference  to  their  color,  much  more 
uniformly  correct :  for,  as  we  have  seen,  the  vesicular  substance  may  be  destitute 
of  internal  pigment-granules,  and  the  blood  in  its  capillary  plexus  may  be  pale 
or  colorless ;  so  that  the  reddish-gray  hue,  which  is  expressed  by  the  term 
"  cineritious,"  may  be  entirely  wanting; 'whilst,  on  the  other  hand,  we  have 
seen  that  certain  of  the  nerve-fibres,  making  up  what  is  commonly  termed  the 
"  white' '  substance  are  of  a  gray  color.     Hence  the  only  valid  distinction  be- 
tween these  two  kinds  of  nervous  matter,  is  that  which  has  reference  to  their 
constitution ; — as  consisting  of  cells  or  vesicles  on  the  one  hand,  or  of  tubes  or 
fibres  on  the  other. 

342.  The  connection  between  the  "fibrous"  and  the  "vesicular"  elements,  in 
the  Nervous  Centres,  is  a  question  to  which  great  attention  has  been  paid  for 
some  time  past  by  Microscopic  observers;  but  it  is  one  of  such  intricacy  and 
difficulty,  that  it  is  still  far  from  being  satisfactorily  elucidated.     It  is  certain, 
however,  that  some  of  the  nerve-fibres  come  into  direct  continuity  with  the 
ganglionic  cells  or  vesicles ;  and  two  principal  modes  of  such  connection  have 
been  observed.     Some  of  the  fine  granular  prolongations  of  the  "  stellate"  nerve- 
cells,  are  traced  into  the  form  of  "gelatinous"  fibres;  and  these,  at  a  greater 
distance  from  their  centre,  exhibit  more  and  more  of  the  tubular  character,  and 
at  last  become  ordinary  '•  tubular"  fibres.     On  the  other  hand,  a  spheroidal 
vesicle  is  often  observed  to  be  directly  continuous  with  a  tubular  fibre,  the 
transparent  membranous  envelop  of  the  latter  being  a  prolongation  of  the  cell- 
wall,  and  the  substances  which  it  contains  being  in  connection  with  those  in- 
cluded within  the  cell-cavity  (Fig.  107,  c,  and  108).     According  to  Prof.  Kbl- 


340 


OF   THE    PRIMARY    TISSUES    OF   THE    HUMAN   BODY. 


liker,1  it  is  rare  among  the  higher  animals  for  a  single  vesicle  to  be  thus  con- 
nected with  more  than  one  nerve-tube,  although  two  or  more  are  frequently 

Fig.  108. 


Connection  between  nerve-fibres  and  nerve-corpuscles ;  from  the  roots  of  a  spinal  nerve  of  the  ray.  A.  A 
nerve-corpuscle,  escaped  by  pressure  from  the  capsule  formed  around  it  by  the  dilated  sheath  of  the  nerve- 
tubule  :  it  shows  also  the  gradual  disappearance  of  the  outer  portion  of  the  substance  of  the  nerve  as  it  comes 
into  relation  with  the  corpuscles.  B.  A  nerve-corpuscle  inclosed  within  a  dilated  portion  of  the  sheath  of  a 
nerve :  part  of  the  granular  material  of  the  corpuscle  is  continuous  with  the  central  substance  of  the  nerve 
in  the  course  of  which  it  is  inserted. 

found  to  issue  from  the  same  corpuscle  in  Fishes  and  Reptiles ;  and  he  regards 
the  remaining  prolongations  of  the  stellate  cells  in  the  light  of  nervi  nervorum. 
It  appears  certain,  however,  that  there  are  many  ganglionic  vesicles  which  do 
not  possess,  any  such  connection  with  nerve-fibres;  whilst  on  the  other  hand,  it 
seems  possible  that  there  may  be  nerve-fibres  which  have  no  such  central  termi- 
nations, but  which  simply  enter  the  ganglionic  masses,  pass  around  and  amongst 


Fig.  109. 


Fig.  110. 


From  the  Gasserian  ganglion  of  an  adult:  a,  a. 
Ganglion  globules  with  their  nucleus,  nucleated  cap- 
sule, and  pigment,  t.  Tubular  fibres,  running  among 
the  globules  in  contact  with  their  capsule,  g.  Gelati- 
nous fibres  also  in  contact  with  the  ganglion  globules. 
—Magnified  320  diameters. 


A  small  piece  of  the  otic  ganglion  of 
the  sheep,  slightly  compressed  ;  showing 
the  interlacement  of  the  internal  fibres, 
and  the  vesicular  matter. — (After  Valen- 
tin.) 


the  cells,  and  then  emerge  without  having  undergone  any  distinct  change,  save 
that  they  present  a  soft  and  varicose  appearance  whilst  threading  their  way  be- 
tween the  vesicles  (Figs.  109  and  110).  This  appearance,  according  to  Mr. 
Newport,  may  be  distinguished  in  the  ganglia  of  the  dorsal  column  of  Articulated 


1  See  his  "Neurological  Observations,"  in  "Kolliker  and  Siebold's  Zeitschrift"  for  1849, 
and  his  "  Mikroskopische  Anatomic,"  band  ii. 


STRUCTURE   OF   NERVOUS    TISSUE.  341 

animals.1 — As  yet,  nothing  is  certainly  known  of  the  purposes  to  which  these 
different  modes  of  connection  are  respectively  subservient. 

343.  The  mode  in  which  the  Nerve-fibres  terminate,  at  their  peripheral 
extremities,  seems  not  to  be  always  the  same.  It  has  been  already  shown  that 
the  motor  fibres,  which  are  distributed  to  the  muscles,  have  no  proper  termina- 
tions; a  series  of  loops,  returning  into  themselves  or  joining  others,  being  formed 
by  the  ultimate  ramifications  of  the  main  trunks  (§  309).  These  loops  in  Man 
seem  to  be  formed  by  complete  tubular  fibres;  but  in  some  of  the  lower  animals 
(as  the  Frog),  the  "axis-band"  seems  to  pass  beyond  its  envelops,  and  to  split 
up  into  more  minute  fibrillae. — So  in  the  tactile  papillae  of  the  Human  Skin,  the 
looped  termination  of  the  fibres  (Fig.  Ill)  can  ordinarily  be  well  made  out  by  the 

Fig.  111. 


Distribution  of  the  Tactile  Nerves  at  the  extremity  of  the  Human  Thumb,  as  seen  in  a  thin  perpendicular 

section  of  the  skin. 

method  described  by  Prof.  Kolliker  (§  239)  [Dr.  Rudolph  Wagner  has  recently 
been  making  the  distribution  of  the  nerves  in  the  skin  of  the  tactile  extremities  of 
the  fingers  his  peculiar  study,  and  has  communicated  the  following  results  of 
his  inquiries  to  the  Royal  Society  of  Glottingen.  What  are  usually  called  the 
tactile  papillae  are  of  two  kinds — namely,  vascular  papillae,  which  only  contain 
capillary  loops;  and  nervous  papillae,  which  are  placed  between  them.  These 
last  have  a  conical  form;  and  each  of  them  contains  in  its  interior  a  peculiar 
corpuscle,  also  of  conical  form,  which  receives  the  finest  of  the  nervous  fibrils 
that  enter  the  papilla.  Each  primitive  nerve-fibre  divides  into  a  great  number 
of  smaller  branches,  to  which  these  tactile  corpuscles  are  attached;  and  thus 
each  is  connected  with  several  corpuscles.  It  is  further  considered  by  Wagner, 
that  each  single  fibre  conducts  the  impressions  made  upon  any  of  these  branches 
to  a  certain  spot  in  the  nervous  centres ;  and  that  thus  but  a  single  sensory  im- 
pression is  produced,  whether  the  corpuscles  supplied  by  any  one  fibre  are  touched 

1  Certain  observations  which  have  been  made  upon  the  nervous  system  of  foetuses,  in 
which  the  brain  and  spinal  cord  were  wanting,  confirm  the  idea  that  this  is  one  of  the 
modes  in  which  the  nerve-trunks  come  into  connection  with  their  ganglionic  centres.  The 
nervous  cords  were  for  the  most  part  developed ;  and  at  their  (so-called)  origins  or  central 
extremities,  they  were  found  to  hang  as  loose  threads  in  the  cavities  of  the  cranium  and 
spine.  On  examining  these  threads,  it  was  found  that  the  nerve-tubes,  of  which  they  con- 
sisted, formed  distinct  loops  ;  each  of  which  was  composed  of  a  fibre  that  entered  the 
cavity,  and  then  returned  from  it.  These  loops  were  imbedded  in  granular  matter,  re- 
sembling that  interposed  between  the  vesicles  in  the  cortical  substance  of  the  brain,  and 
perhaps  to  be  regarded  as  vesicular  matter  in  an  early  stage  of  its  formation.  All  that  is 
known  of  the  laws  of  formation  of  such  irregular  productions,  leads  to  the  belief  that  we 
may  rightly  consider  this  arrangement  of  the  nerve-tubes  as  one  which  exists  in  the  nerv- 
ous centres,  when  they  are  normally  developed.  (See  Dr.  Lonsdale,  in  "Edin.  Med. 
and  Surg.  Journal,"  No.  157  ;  and  Mr.  Paget  in  "Brit,  and  For.  Med.  Review,"  No.  43, 
p.  273.) 


342 


OF   THE   PRIMARY   TISSUES   OF   THE    HUMAN   BODY. 


separately,  or  all  together,1  Ed.~\;  but  in  the  tail  of  the  Tadpole,  as  also  in  the 
mesentery  of  the  Amphibia,  it  was  first  observed  by  Schwann,2  and  has  been  since 
confirmed  by  Dr.  Sharpey,3  that  the  ordinary  primitive  nerve-fibres,  after  separat- 
ing from  the  fasciculi,  divide  into  fibrils  of  much  smaller  size,  bearing  a  strong 
resemblance  to  the  "gelatinous"  kind,  which  spread  out  in  various  directions,  and 
form  a  plexus  not  unlike  that  of  the  capillaries.  The  origin  of  these  plexuses  has 
been  traced  by  Prof.  Kolliker;4  who  has  found  that  they  formed,  like  capillary 
plexuses  (§  294),  by  the  inosculation  of  the  prolongations  of  radiating  cells, 
whose  centres  are  at  a  considerable  distance  from  each  other.  Looped  termina- 
tions may  be  seen  in  the  nerves  supplying  the  dental  sacculi  (Fig.  112),  and  in 

those  of  the  conical  papillae  of  the  tongue; 

Fig.  112.  on  the  other  hand,  in  the  fungiform  papillae 

of  the  tongue,  the  Author,  after  a  very  at- 
tentive search  for  them  (in  conjunction  with 
Messrs.  Bowman,  Kiernan,  and  T.  Whar- 
ton  Jones),  could  not  succeed  in  distinguish- 
ing them;  no  free  extremities,  however, 
were  discernible;  and  some  appearances 
were  seen,  which  indicated  that  the  axis- 
band  is  here  also  prolonged  beyond  its  en- 
velops, and  is  continued  as  a  gelatinous 
fibre  into  the  tissue  at  the  apex  of  the  pa- 
pilla, where  it  ceases  to  be  distinguishable. 
— It  will  hereafter  be  shown  that,  in  the 
Retina,  in  some  parts  of  the  internal  Ear, 
and  perhaps  also  on  the  Olfactory  surface, 
the  peripheral  fibres  come  into  relation  with 
true  ganglionic  cells;  and  it  may  be  ques- 
tioned whether  it  be  not  as  requisite  for  the 
reception  of  any  other  kind  of  sensory  im- 
pressions than  those  of  a  mere  mechanical 
nature,  that  a  ganglionic  vesicle,  or  its  equiv- 
alent under  some  other  aspect,  should  be  in 
connection  with  the  peripheral  expansions  of 
the  sensory  nerves,  as  it  is  for  the  origination 
of  motor  impulses,  that  ganglionic  vesicles 
should  be  in  relation  with  them  in  the  cen- 
tral organs. 

344.  One  very  peculiar  mode  of  termination  of  certain  of  the  Nervous  fibres, 
the  physiological  import  of  which,  however,  is  entirely  unknown,  is  in  the  bodies 
termed  Pacinian,  after  Pacini,  the  first  writer  who  gave  an  account  of  their 
internal  structure,  and  demonstrated  their  essential  connection  with  the  nervous 
fibres.  His  researches  have  been  followed  up  by  Henle  and  Kblliker,5  and  also 
by  Mr.  Bowman.8  These  bodies  are  found  in  considerable  numbers  attached  to 
the  branches  of  the  nerves  of  the  hand  and  foot,  as  they  pass  through  the  sub- 
cutaneous fat  in  their  way  to  the  skin  (Fig.  113,  B)  ;  they  are  also  occasionally 
met  with  on  subcutaneous  nerves  elsewhere,  and  they  have  been  discovered  on 
the  nerves  of  the  solar  plexus  in  the  abdominal  cavity.  Their  form  usually 
approaches  to  the  oval,  though  they  are  generally  more  or  less  curved  or  reni- 

1  "Brit,  and  For.  Med.  Chir.  Rev.,"  from  "Gaz.  Med.,"  Mars  6. 

2  "  Medizinischen  Zeitung,"  Aug.,  1837. 

3  Introduction  to  "Quain's  Elements,"  vol.  ii.  p.  169,  Am.  Ed. 

4  "Annales  des  Sciences  Naturelles,"  Zool.,  Aout,  1846. 

5  "Ueber  die  Pacinischen  Korperchen,"  Zurich,  1844. 


Terminal  nerves,  on  the  sac  of  the  second 
molar  tooth  of  the  lower  jaw,  in  the  sheep ; 
showing  the  arrangement  in  loops.— (After 
Valentin.) 


6  "Cyclopaedia  of  Anatomy  and  Physiology,"  Art.  " 
jwman's  "Physiological  Anatomy,"  p.  345,  Am.  Ed. 


Pacinian  Bodies,"  and  Todd  and 


STRUCTURE   OF   NERVOUS   TISSUE. 


343 


form;  and  their  mean  size  in  the  adult  is  from  l-15th  to  l-10th  of  an  inch  in 
length,  and  from  l-26th  to  l-20th  of  an  inch  in  breadth.  They  are  attached 
to  the  branches  of  the  nerves  on  which  they  cluster,  by  slender  peduncles,  each 
of  which  consists  of  a  single  tubular  nerve-fibre,  with  one  or  more  fine  blood- 
vessels, and  a  sheath  of  areolar  tissue  (Fig.  113,  A,  a,  6).  The  corpuscle  itself 
consists  of  numerous  concentric  capsules,  of  a  delicate  fibrous  membrane,  in- 
closing each  other  like  the  coats  of  an  onion,  to  the  number,  sometimes,  of 
between  forty  and  sixty ;  those  which  form  the  internal  portion  (c)  being  closer 
together  than  those  of  the  outer  part  (d).  These  capsules  are  kept  apart  by  a 
transparent  fluid  (probably  albuminous),  which  also  occupies  the  central  cavity. 
The  nerve-fibre  gradually  loses  its  neurilemma  as  it  passes  through  the  series  of 
capsules,  but  still  retains  its  dark  double  contour  until  it  enters  the  cavity;  from 
that  point,  however,  it  presents  the  cha- 
racters of  the  " gelatinous"  fibres,  being  Fig-  H3. 
pale,  flattened,  granular,  and  destitute  of  A  B 
a  tubular  envelop;  and  this  it  usually 
retains  as  far  as  its  termination.  The 
fibre  usually  ends  in  a  sort  of  knob  at  the 
farthest  extremity  of  the  capsule;  some- 
times, however,  it  bifurcates,  and  each 
division  ends  in  a  similar  knob;  and 
still  more  rarely,  it  separates  into  three 
parts  (/).  The  constant  presence  of 
these  bodies,  in  certain  regions  of  the 
body,  in  perfectly  healthy  individuals  of 
all  ages,  and  even  in  the  foetus,  is  quite 
sufficient  to  negative  the  idea  put  for- 
ward by  Cruveilhier  and  others,  that 
they  are  morbid  or  accidental  produc- 
tions, probably  resulting  from  pressure 
applied  to  the  nerves.  On  the  other 
hand,  the  suggestion  of  Pacini,  adopted 
by  Henle  and  Kblliker,  that  they  are 
analogous  in  function  to  the  electrical 
organs  of  Fishes  (to  which  they  bear  a 
certain  degree  of  structural  resemblance), 
has  no  sufficient  evidence  in  its  favor. 

345.  The  Chemical  constitution  of 
the  Nervous  matter  is  peculiar,  but  has 
not  yet  been  satisfactorily  made  out. 
An  acquaintance  with  its  general  features 
is  of  importance,  however,  in  leading  us 
to  recognize  in  the  excretions  the  results 
of  its  decomposition.  The  following, 
according  to  L'Heritier,1  is  the  relative  proportion  of  the  different  constituents 
in  individuals  of  different  classes : — • 


Water       .         ... 

Albumen 

Fat  ... 

Osmazome2  and  Salts 

Phosphorus 


1  "  Traite  de  Chimie  Pathologique,"  p.  596. 

2  It  is  probable  that,  in  the  above  analyses  of  L'Heritier,  the  Cerebric  acid,  which  is 
not  soluble  in  ether,  is  included  under  the  head  of  Osmazome ;  for  the  analyses  of  Denis 


Human  Pacinian  Corptisdes:  A,  single  corpus- 
cle, highly  magnified,  showing  a  its  peduncle,  b  its 
contained  nerve-fibre ;  c,  outer  layers  and  d  inner 
layers  of  the  capsule ;  e,  nerve-fibre  become  pale 
in  its  passage  through  the  interior  of  the  corpuscle ; 
/,  its  subdivision  and  termination :  B,  portion  of 
digital  nerves  with  Pacinian  corpuscles  attached, 
rather  less  than  the  natural  size. 


Infants. 

Youths. 

Adults. 

Aged  Persons. 

Idiots. 

82.79 

74.26 

72.51 

73.85 

70.93 

7.00 

10.20 

9.40 

8.65 

8.40 

3.45 

5.30 

6.10 

4.32 

5.00 

5.96 

8.59 

10.19 

12.18 

14.82 

0.80 

1.65 

1.80 

1.00 

0.85 

344  OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN    BODY. 

According  to  M.  Fremy,  the  Phosphorus  is  combined  with  part  of  the  fatty 
matter;  and  forms  with  it  two  peculiar  fatty  acids,  termed  by  him  the  Cerebric 
and  Oleoplwsphoric  (§  44).  Cholesterin  has  also  been  extracted  from  the  brain 
by  M.  Fremy  in  considerable  quantity;  and  is  perhaps  to  be  regarded  as  one  of 
the  products  of  its  disintegration  (§  43).  The  proportion  of  Fixed  Salts  is 
about  3£  parts  in  100  of  dry  Cerebral  matter;  the  nature  of  these  has  not  yet 
been  satisfactorily  determined,  but  they  seem  to  be  chiefly  alkaline  phosphates 
and  carbonates.  According  to  Lassaigne,  the  chemical  composition  of  the 
"cortical"  and  "  medullary"  substances  of  the  brain  is  essentially  different;  the 
former  containing  85  per  cent,  of  water,  whilst  the  latter  has  only  73;  the  cor- 
tical substance  having  also  3.7  per  cent,  of  a  red  fatty  matter,  of  which  the 
medullary  has  scarcely  any;  and  being  almost  entirely  destitute  of  the  white 
fatty  matter,  which  exists  in  large  proportion  in  the  latter.  The  Albuminous 
matter  in  the  above  analyses  probably  constitutes  the  walls  of  the  nerve-cells 
and  nerve-tubes  (as  well  as  of  the  capillary  bloodvessels),  and  that  portion  of 
their  contents  which  is  represented  in  the  nerve-tubes  by  the  "axis-band;"  whilst 
the  phospJiorized  fats  seem  to  form  the  "  white  substance  of  Schwann"  in  the 
tubular  fibres,  and  a  considerable  part  of  the  contents  of  the  vesicles.  It  will 
be  remarked,  that  the  amount  of  phosphorus  is  the  greatest  at  the  period  of 
greatest  mental  vigor;  and  that  in  infancy,  old  age,  and  idiocy,  the  proportion 
is  not  above  half  that  which  is  present  during  the  adolescent  and  adult  periods. 
346.  The  Nervous  System  is  very  copiously  supplied  with  Bloodvessels;  the 
arrangement  of  which  varies  according  to  the  form  of  the  elementary  parts  in 
which  they  are  distributed.  Thus,  in  the  Vesicular  substance  of  the  nervous 
centres,  the  capillaries  form  a  minute  network  (Fig.  114),  in  the  interstices  of 
which  the  ganglionic  cells  are  included.  In  the  Fibrous  substance,  the  capil- 
laries are  distributed  much  on  the  same  plan  as  in  Muscular  tissue  (Fig.  101); 
the  network  being  composed  of  straight  vessels,  which  run  along  the  course  of 
the  fibres,  passing  between  the  nerve-tubes,  and  which  are  connected  at  intervals 
by  transverse  branches.  And  at  the  sensory  extremities  of  the  nerves,  we  find 
loops  of  capillaries  (Fig.  115)  arching  over  their  terminal  and  probably  looped 
filaments.  The  Braiit  of  Man,  taken  en  masse,  has  been  estimated  to  receive  one- 
sixth  of  the  whole  amount  of  blood,  although  its  weight  is  not  usually  more  than 
one-fortieth  part  of  that  of  the  entire  body.  Whether  or  not  this  estimate  be  pre- 
cisely correct,  there  can  be  no  doubt  that  it  receives  far  more  blood  than  any  other 
part  containing  the  same  amount  of  solid  matter.  Now  this  copious  supply 
of  blood  evidently  has  reference  to  two  distinct  objects ;  first,  to  supply  the  ne- 

Fig.  114.  Fig.  115. 


Capillary  network  of  Nervous  Centres.  Distribution  of  Capillaries  of  the  surface 

of  the  Skin  of  the  finger. 

cessary  conditions  for  the  action  of  the  Nervous  system  ;  and,  secondly,  to  main- 
tain its  nutrition.  Many  circumstances  lead  to  the  conclusion  that,  in  the  Nerv- 
ous as  in  the  Muscular  system,  every  vital  operation  is  necessarily  connected  with 

and  other  chemists  give  a  much  higher  proportion  to  the  Phosphorized  Fat,  and  a  much 
smaller  one  to  the  ill-defined  compounds  represented  by  the  designation  Osmazome. 


STRUCTURE   OF   NERVOUS    TISSUE.  345 

a  certain  change  of  composition,  so  that  no  manifestation  of  nervous  power  can 
take  place,  unless  this  change  can  be  effected  (§§  358 — 362).  There  is  strong 
reason  to  believe,  further,  that  this  change  essentially  consists  in  the  union  of 
Oxygen  conveyed  by  the  arterial  blood,  with  the  elements  of  the  proper  Nervous 
matter  :  and  that  this  union  consequently  involves  the  death  and  disintegration 
of  a  certain  amount  of  the  tissue,  the  reproduction  of  which,  therefore,  will  be 
requisite,  in  order  that  the  system  may  be  maintained  in  a  state  fit  for  action. 
This  reproduction  is  effected  by  the  nutritive  process,  which  takes  place  at  the 
expense  of  other  constituents  of  the  blood ;  and  it  will  proceed  most  vigorously 
in  the  intervals,  when  the  active  powers  of  the  nervous  system  are  not  being 
called  into  operation. — The  proofs  of  this  continual  waste  and  reproduction  of 
the  Nervous  substance,  are  partly  afforded  by  the  appearance  of  the  products  of 
its  decomposition  in  the  excretions,  and  by  the  demand  which  is  set  up  for  the 
materials  for  its  reparation ;  these  being  found  to  accord  in  amount,  as  will  be 
shown  hereafter,  with  the  degree  of  its  functional  activity.  But  evidence  of 
another  kind  may  be  drawn  from  the  microscopic  appearances  presented  by  the 
cortical  substance  of  the  Brain.  For  ganglionic  vesicles  may  be  observed  in  all 
stages  of  development ;  and  numerous  bodies  resembling  free  nuclei  are  seen  in 
the  granular  substance  in  which  these  are  imbedded.  It  is  surmised  by  Henle,1 
from  the  comparative  aspects  of  the  external  and  internal  layers  of  the  cortical 
substance,  that  there  is  as  continual  a  succession  of  nerve-cells,  as  there  is  of  epi- 
dermic cells  ;  their  development  commencing  at  the  surface,  where  they  are  most 
Copiously  supplied  with  bloodvessels  from  the  pia  mater  ;  and  proceeding  as  they 
are  carried  towards  the  inner  layers,  where  they  come  into  more  immediate  rela- 
tion with  the  tubular  portion  of  the  nervous  tissue.  This  change  of  place  is  pro- 
bably due  to  the  continual  death  and  disintegration  of  the  mature  cells,  where 
they  are  connected  with  the  fibres,  and  the  equally  rapid  production  of  new 
generations  at  the  external  surface ; — the  newly-formed  G-anglionic  cells  being 
thus  carried  inwards,  in  precisely  the  same  manner  that  the  Epidermic  cells  are 
carried  outwards  (§  240). 

347.  The  maintenance  of  the  integrity  of  the  Nervous  tissue,  by  the  due  per- 
formance of  the  nutritive  operations,  is  not  less  dependent  than  that  of  the  Mus- 
cular (§  313),  upon  the  continuance  of  its  functional  activity;  indeed,  it  will  be 
presently  shown,  that  degenerative  changes  manifest  themselves  at  a  much  ear- 
lier period  after  the  interruption  of  that  activity,  so  as  to  indicate  that  the  de- 
pendence is  yet  closer. — It  has  long  been  known  that,  when  disease  of  the  Optic 
nerve  or  of  its  ganglionic  centre  occasions  complete  Amaurosis,  the  Retina  comes 
in  time  to  lose  its  characteristic  appearance,  and  the  portion  of  the  Nerve  in 
front  of  the  seat  of  the  disease  presents  an  atrophied  aspect.  And  it  has  been 
shown  by  Valentin/  that,  notwithstanding  the  general  appearance  of  the  eye 
may  be  unchanged,  the  texture  of  the  retina  becomes  completely  altered;  for 
it  is  found  to  be  composed  of  white  cylindrical  threads  interlaced  together,  with- 
out presenting  any  appearance  of  the  ganglionic  vesicles  or  of  the  tubular  nerve- 
fibres  proper  to  the  part;  and  the  yellow  spot  of  Soemmering  becomes  paler,  and 
is  at  last  indistinguishable.  But  if  a  very  slight  degree  of  sensibility  to  light 
remain  (showing  that  some  power  of  transmission  still  exists  in  the  optic  nerve), 
these  changes  are  much  less  decided.  Further,  when  the  sight  is  destroyed  by 
a  disease  or  injury  which  prevents  the  light  from  passing  through  the  pupil,  the 
whole  eye  becomes  more  or  less  atrophied;  and  the  retina  and  optic  nerve  are 
found  after  death  (if  the  morbid  condition  have  lasted  sufficiently  long)  to  have 
lost  their  characteristic  structure.  It  is  probable  that  in  the  latter  case,  as  in 
that  of  Muscles  long  disused,  a  renewal  of  the  normal  nutrition,  and  a  re-esta- 
blishment of  the  structural  and  functional  integrity  of  the  tissues,  takes  place 

1  "Traite  d'Anatomie  Generate,"  traduit  par  Jourdan;  torn.  ii.  p.  330. 

2  "De  Functionibus  Nervorum  Cerebralium,  et  Nervi  Sympathetic!,"  Bernse,  1839. 


346  OP   THE   PRIMARY   TISSUES    OF   THE   HUMAN   BODY. 

(provided  the  degeneration  have  not  proceeded  too  far),  when  light  is  again 
allowed  to  act  upon  the  retina.  For  it  may  be  observed  that,  when  an  eye  has 
been  from  any  cause  withdrawn  for  a  long  period  from  its  normal  state  of  acti- 
vity, and  is  again  placed  in  a  condition  to  be  employed  (as  when  it  has  been 
turned  inwards  by  extreme  Strabismus,  and  has  been  brought  by  operation  into 
the  correct  axis;  or  when  closure  of  the  pupil,  or  the  extension  of  an  opacity  over 
the  central  part  of  the  cornea,  has  been  remedied  by  making  an  artificial  pupil), 
the  recovery  of  good  sight  is  by  no  means  immediate,  but  often  requires  a  con- 
siderable lapse  of  time,  like  the  recovery  of  muscular  power  in  a  limb  which  has 
become  atrophied  from  paralysis. — Various  experimental  results  confirm  this 
view.  Thus  it  was  found  by  Grunther  and  Schbn,  that  when  a  nerve  is  divided, 
the  peripheral  portion  exhibits  obvious  degenerative  changes  within  the  space  of 
a  week;1  and  these  changes  have  been  shown  by  Nasse  to  be  still  more  decided 
some  months  afterwards.3  The  most  minute  and  interesting  researches  yet 
made  upon  this  point,  however,  are  those  of  Dr.  Aug.  Waller;3  who  has  taken 
for  the  subject  of  his  investigations  the  alterations  produced  in  the  nerves  of  the 
Frog's  tongue,  the  papillae  of  which  are  supplied  by  the  glosso-pharyngeal. 
Within  three  or  four  days  after  the  division  of  the  trunk  of  this  nerve  on  one 
side,  a  difference  begins  to  manifest  itself  between  the  fibrils  contained  in  the 
papillae  which  it  supplies,  and  those  of  the  sound  side ;  for  a  slightly  turbid  or 
coagulated  appearance  is  seen  in  the  contents  of  the  tubes,  which  no  longer  ap- 
pear to  fill  them ;  and  the  difference  is  still  more  marked  twenty-four  hours  after 
death.  About  five  or  six  days  after  the  section,  the  alteration  of  the  nerve- 
tubes,  produced  by  the  coagulation  of  their  medullary  contents,  becomes  very 
obvious ;  the  diameter  of  the  altered  tubes  is  about  a  fourth  less  than  that  of  the 
sound  ones;  and  in  many  parts,  the  membranous  tubules  cannot  be  distinguished, 
the  coagulated  masses  appearing  to  be  completely  disjointed  from  one  another. 
On  the  eighth  and  ninth  days  the  coagulated  particles. become  still  more  discon- 
nected, and  are  in  parts  removed  by  absorption ;  on  the  tenth  day,  the  particles 
begin  to  assume  a  granular  texture ;  and  by  about  the  twentieth  day  they  are 
completely  reduced  to  the  granular  state,  the  presence  of  the  nervous  element 
being  only  indicated  by  rows  of  numerous  dark  granules,  arranged  like  the  beads 
of  a  necklace.  The  resistance  of  these  granular  bodies  to  chemical  agents  has  been 
found  by  Dr.  Waller  to  be  most  remarkable;  they  remain  unaffected  by  acids, 
alkalies,  and  ether;  and  he  has  seen  them  apparently  unaltered  after  a  lapse  of 
more  than  five  months. — As  all  the  nutritive  changes  in  cold-blooded  animals 
go  on  with  greater  rapidity  at  a  high  than  at  a  low  temperature,  so  should  we 
expect  that  the  degenerative  changes  would  likewise,  upon  the  principles  for- 
merly laid  down  (§  114);  and  it  is  an  interesting  confirmation  of  this  view  to 
find,  that  Dr.  Waller  has  noticed  that  the  alterations  consequent  upon  section 
of  the  nerves,  make  themselves  apparent  in  frogs  much  earlier  in  summer  than 
they  do  in  winter. 

348.  The  first  development  of  the  Nerve-tubes  appears  to  take  place,  like  that 
of  Muscular  fibre,  by  the  coalescence  of  a  number  of  primary  cells  into  a  con- 
tinuous tube;  for  although  the  primary  nervous  cell  has  not  yet  been  made  out 
with  precision,  the  nuclei  of  what  seem  to  be  the  original  cells  may  frequently 
be  seen  in  the  fully-formed  tube,  lying  between  their  membranous  walls  and  the 
white  substance  of  Schwann  (Fig.  106,  c).  When  first  a  nerve-fibre  can  be  recog- 
nized as  such,  it  has  a  strong  resemblance  to  the  t(  gelatinous"  fibres  of  the 
sympathetic  trunks;  being  a  cord  of  small  diameter,  without  any  clear  distinc- 
tion between  the  tube  and  its  contents,  of  granular  consistence,  and  having 
nuclei  at  no  great  distance  from  each  other.  The  substance  of  the  fibre,  at  this 
period,  seems  to  correspond  with  the  axis-band  of  the  fully-formed  nerve-tube; 

1  "Miiller's  Archiv.,"  1840,  p.  276.  2  Op.  cit.,  1839,  p.  409. 

3  "Philosophical  Transactions,"  1850,  p.  423,  et  seq. 


STRUCTURE   OP   NERVOUS   TISSUE.  347 

the  white  substance  of  Schwann  is  subsequently  deposited  around  it,  separating 
it  from  the  membranous  tubular  envelop. — The  statements  of  Schwann  and 
Kolliker  respecting  the  origin  of  the  peripheral  plexuses,  have  been  already  re- 
ferred to  (§  343).  It  is  believed  by  the  last-named  observer  (loc.  cit.),  that 
the  fibres  of  the  trunks  with  which  these  plexuses  become  connected,  originate 
in  cells  which  become  fusiform  by  elongation,  and  which  then  coalesce  at  their 
extremities;  and  these  seem  to  increase,  after  the  first  formation  of  the  trunks, 
by  the  longitudinal  subdivision  of  fusiform  cells  which  had  not  previously  un- 
dergone complete  metamorphosis  into  fibres,  or  by  the  development  of  cells  de 
novo. — The  first  development  of  the  vesicular  substance  appears  to  take  place  on 
the  same  plan  with  its  subsequent  renewal;  that  is,  from  free  nuclei,  around 
which  the  intervening  granular  matter  seems  to  collect,  the  cell-walls  being  of 
subsequent  formation. 

349.  The  regeneration  of  Nervous  tubuli  which  have  been  destroyed,  takes 
place  in  continuity  with  those  which  have  been  left  sound.  This  is  readily  proved, 
on  the  one  hand,  by  the  return  of  the  sensory  and  motor  endowments  of  the 
part  whose  nerves  have  been  separated;  and  on  the  other,  by  microscopic  exa- 
mination of  the  reunited  trunks  themselves.  All  our  knowledge  of  the  func- 
tions of  the  Nervous  System  leads  to  the  belief,  that  perfect  continuity  of  the 
Nerve-tubes  is  requisite  for  the  conduction  of  an  impression  of  any  kind,  whether 
this  be  destined  to  produce  motion  or  sensation;  and  various  facts,  well  known 
to  Surgeons,  prove  that  such  continuity  may  be  re-established  after  it  has  been 
completely  interrupted.  In  the  various  operations  which  are  practised  for  the 
restoration  of  lost  parts,  a  portion  of  tissue  removed  from  one  spot  is  grafted 
(as  it  were)  upon  another;  its  original  attachments  are  more  or  less  completely 
severed,  frequently  altogether  destroyed,  and  new  ones  are  formed.  Now,  in 
such  a  part,  so  long  as  its  original  connections  exist,  and  the  new  ones  are  not 
completely  formed,  the  sensation  is  referred  to  the  spot  from  which  it  was  taken : 
thus,  when  a  new  nose  is  made,  by  partly  detaching  and  bringing  down  a  piece 
of  skin  from  the  forehead,  the  patient  at  first  feels,  when  anything  touches  the 
tip  of  his  nose,  as  if  the  contact  were  really  with  the  upper  part  of  his  forehead. 
After  time  has  been  given,  however,  for  the  establishment  of  new  connections 
with  the  parts  into  whose  neighborhood  it  has  been  brought,  the  old  connections 
of  the  grafted  portion  are  completely  severed,  and  an  interval  ensues  during 
which  it  frequently  loses  all  sensibility;  but  after  a  time  its  power  of  feeling  is 
restored,  and  the  sensations  received  through  it  are  referred  to  the  right  spot. 
A  more  familiar  case  is  the  regeneration  of  Skin,  containing  sensory  nerves, 
which  takes  place  in  the  well-managed  healing  of  wounds  involving  loss  of  sub- 
stance. Here  there  must  obviously  be,  not  merely  a  prolongation  of  the  nerve- 
tubes  from  the  subjacent  and  surrounding  trunks,  but  also  a  formation  of  new 
sensory  papillae.  A  still  more  striking  example  of  the  regeneration  of  Nervous 
tissue,  however,  is  to  be  found  in  those  cases  (of  which  there  are  now  several  on 
record)  in  which  portions  of  the  extremities,  that  have  been  completely  severed 
by  accident,  have  been  made  to  adhere  to  the  stump,  and  have,  in  time,  com- 
pletely recovered  their  connection  with  the  Nervous  as  with  the  other  systems, 
as  is  indicated  by  the  restoration  of  their  motor  and  sensory  endowments. — The 
evidence  is  still  more  satisfactory,  however,  when  it  is  furnished  not  merely  by 
the  return  of  functional  activity,  but  by  structural  examination  of  the  divided 
part.  This  investigation  has  been  recently  pursued  by  M.  Brown-Sequard,  with 
very  surprising  results.  Having  divided  the  Sciatic  nerve  of  a  Guinea-pig,  he 
observed  indications  of  a  return  of  sensibility  in  the  limb  supplied  by  it,  as 
early  as  a  month  after  the  operation ;  within  another  month,  the  sensibility  had 
decidedly  augmented,  though  it  was  still  much  inferior  to  that  of  the  sound 
limb,  and  the  muscles  then  began  again  to  act;  six  months  after  the  section,  the 
sensibility  appeared  to  have  completely  returned,  and  the  motor  power  to  have  been 


348  OF   THE   PRIMARY   TISSUES   OF   THE    HUMAN   BODY. 

almost  entirely  recovered;  and  at  the  end  of  eleven  months,  no  difference  could 
be  discovered  in  the  motor  power  of  the  two  limbs.  The  animal  was  killed 
twelve  months  after  the  operation ;  and  a  careful  examination  having  been  insti- 
tuted into  the  state  of  the  part  of  the  nerve  where  the  division  had  been  made, 
no  indication  of  the  division  could  be  discovered,  either  with  the  naked  eye,  or 
with  the  microscope.  The  usual  swelling  at  the  point  of  reunion  had  been  dis- 
tinguishable up  to  about  the  sixth  month;  but  it  had  then  disappeared. — The 
results  of  M.  Brown- Sequard's  experiments  upon  the  Spinal  Cord  are  yet  more 
striking.  The  spinal  cord  of  a  pigeon  having  been  divided  between  the  fifth 
and  sixth  dorsal  vertebras,  the  completeness  of  the  section  was  manifested  by 
the  entire  paralysis  of  the  posterior  part  of  the  body,  as  regarded  both  sensation 
and  voluntary  movement;  at  the  end  of  three  months,  however,  voluntary  move- 
ments began  to  show  themselves  in  the  midst  of  reflex  actions,  and  sensibility 
also  reappeared ;  these  powers  gradually  augmented,  and  six  months  after  the 
operation  the  bird  could  stand  for  some  minutes,  though  it  fell  if  it  attempted 
to  walk;  in  the  course  of  the  seventh  month  it  began  to  walk,  but  unsteadily, 
helping  itself  by  its  wings;  by  the  end  of  the  eighth  month  it  could  walk  slowly 
without  support,  though  it  fell  over  if  it  attempted  to  walk  fast,  unless  it  sup- 
ported itself  by  its  wings ;  twelve  months  after  the  operation,  it  could  run ;  and 
at  the  end  of  the  fifteenth  month  its  progression  seemed  in  all  respects  normal, 
save  that  a  certain  degree  of  stiffness  remained  in  its  gait.  In  several  other 
cases,  in  which  a  partial  section  of  the  spinal  cord  had  been  made,  and  in  which 
a  complete  return  of  functional  power  had  taken  place,  a  careful  examination 
was  made  of  the  divided  part;  this  was  distinguishable  by  a  whitish  cicatrix, 
the  substance  of  which  was  found  to  be  in  great  part  made  up  of  fibres  of  areo- 
lar  tissue,  the  direction  of  which  was  transverse  or  oblique;  but  these  were 
crossed  by  great  numbers  of  nerve-tubes  running  in  a  longitudinal  direction, 
which  exhibited  the  characteristic  double  contour,  and  were  uninterruptedly 
continuous  through  the  whole  extent  of  the  cicatrix;  and  amongst  these  were 
scattered  some  ganglionic  corpuscles.1 

350.  Functions  of  Nervous  Tissue. — The  peculiar  vital  endowments  of  the 
Nervous  tissue  can  only  be  exhibited,  when  the  two  distinct  forms  of  it  are 
united  in  such  a  manner  as  to  constitute  a  "nervous  system."  This  system  in 
its  simplest  condition,  is  composed  of  an  expansion  of  nerve-fibres  over  the  sur- 
face of  the  body,  or  of  some  part  of  it;  of  an  afferent  trunk  formed  by  the  junc- 
tion of  these  fibres,  which  proceeds  towards  a  ganglion  wherein  it  terminates; 
of  a  ganglionic  centre  containing  vesicular  nervous  matter,  with  which  the  nerve- 
fibres  come  into  connection;  of  an  efferent  trunk,  issuing  from  the  ganglion,  and 
proceeding  towards  the  muscles;  and  of  &  plexus  of  fibres  into  which  that  trunk 

1  See  the  "Gazette  Medicale,"  1849,  No.  45,  and  1851,  No.  30;  also  the  "Comptes 
Rendus  de  la  Societe  de  Biologic,"  1849, 1850. — The  successful  issue  of  these  experiments 
is  in  great  part  attributable  to  the  sedulous  care  bestowed  by  M.  Brown-Sequard  upon  the 
animals  which  are  the  subjects  of  them.  It  frequently  happens  that  pathological  changes 
take  place  in  the  paralyzed  parts,  which  may  lead  to  serious  or  even  fatal  consequences ; 
and  such  changes  have  been  attributed  to  the  direct  influence  of  the  withdrawal  of  nervous 
power,  upon  the  nutritive  processes.  It  has  been  shown,  however,  by  an  experiment  of 
M.  Brown-Sequard' s,  that  no  such  influence  exists;  and  that  the  pathological  changes  in 
question  are  due  to  the  want  of  power  on  the  part  of  the  animals  to  withdraw  their  limbs 
from  sources  of  injury.  For,  having  divided  the  sciatic  nerve  in  a  number  of  rabbits  and 
guinea-pigs,  he  placed  some  of  the  animals  at  liberty  in  a  room  with  a  paved  floor,  whilst 
he  confined  others  in  a  box,  whose  bottom  was  thickly  covered  with  bran  and  hay.  In  a 
fortnight,  the  former  set  exhibited  an  obvious  disordered  action  in  the  paralyzed  limbs, 
the  claws  being  entirely  lost,  the  extremities  of  the  feet  swollen,  and  the  exposed  tissues 
red,  engorged,  and  covered  with  fleshy  granulations ;  and  at  the  end  of  a  month  these  alter- 
ations were  more  decided,  the  bones  being  denuded,  and  necrosis  having  commenced  in 
them.  On  the  other  hand,  among  the  animals  confined  in  boxes  with  a  soft  floor,  no  such 
injuries  had  accrued. 


FUNCTIONS   OF   NERVOUS    TISSUE.  349 

subdivides,  and  which  comes  into  intimate  relation  with  the  elements  of  the 
Muscular  tissue. — Such  an  apparatus,  altogether  designated  as  the  "nervous 
circle,"  seems  to  constitute  the  entire  Nervous  System  of  some  among  the  lower 
animals ;  and  it  may  be  multiplied  to  any  extent,  so  as  to  supply  a  great  number 
of  similar  organs  (as  we  see  in  the  circular  gangliated  cord  surrounding  the 
mouth  of  the  Star-fish,  and  the  double  gangliated  column  which  extends  along 
the  body  of  the  Worm  or  the  Centipede),  without  any  essential  change  in  its 
endowments.  And  even  in  Man,  we  shall  hereafter  find  that  a  considerable  part 
of  the  Nervous  system  is  constructed  upon  this  simple  plan ;  although  its  uni- 
formity is  obscured  by  the  frequent  coalescence  of  ganglionic  centres  that  remain 
distinct  in  the  lower  animals,  and  by  the  greater  variety  in  the  distribution  of 
the  nerve-trunks,  in  accordance  with  the  dissimilarity  between  the  several  organs 
with  which  they  are  connected. — The  modus  operandi  of  such  a  system  is  as 
follows.  By  contact,  pressure,  or  some  other  form  of  mechanical  agency,  an 
impression  is  made  upon  the  peripheral  extremities  of  the  afferent  nerves;  and 
this  impression,  or  rather,  the  change  induced  by  it  in  the  condition  of  the 
nerve-fibre,  is  transmitted  by  the  nerve-trunk  to  the  central  ganglion.  In  this 
ganglion,  the  influence  transmitted  by  the  afferent  trunk  excites  a  reactive  change; 
the  occurrence  of  which  is  indicated  by  the  transmission)  along  the  efferent 
nerves,  of  an  influence,  which,  being  distributed  to  the  muscular  substance, 
excites  it  to  contraction.  All  this  takes  place  so  instantaneously,  that  the  move- 
ment follows  immediately  upon  the  application  of  the  stimulus.  Actions  of  this 
kind,  which  do  not  involve  Sensation  as  one  of  their  conditions,  and  which  are 
executed  in  direct  and  unconscious  respondence  to  external  stimuli,  are  now 
generally  termed  "reflex;"  though  the  designation  " exci to-motor"  (originally 
proposed  by  Dr.  M.  Hall)  would  perhaps  be  more  appropriate,  as  distinguishing 
this  class  of  actions  from  others  which  have  an  equal  claim  to  the  term  "  reflex." 
351.  Such  operations  as  the  foregoing,  however,  must  be  considered  as  consti- 
tuting the  lowest  kind  of  functional  activity  of  the  Nervous  system;  since  they 
serve  only  an  internuncial  purpose,  that  of  bringing  the  different  parts  of  the 
bodily  organism  into  co-operative  relationship  with  each  other.  A  much  higher 
attribute  is  that  by  which  it  brings  the  conscious  Mind  into  relationship  with 
the  body,  and,  through  its  medium,  with  the  external  world;  informing  it, 
through  the  impressions  received  by  the  organs  of  sensation,  of  the  changes 
which  the  material  objects  around  it  undergo;  and  enabling  it  to  react  upon 
these,  by  the  instrumentality  of  its  motor  apparatus.  Certain  ganglionic  centres, 
distinct  from  those  of  simply-reflex  action,  are  set  apart  for  these  purposes; 
but  we  can  trace  no  essential  peculiarity  in  their  structure,  which  can  in  any 
way  indicate  their  possession  of  this  extraordinary  endowment.  They  still  con- 
sist of  vesicular  matter,  with  afferent  or  sensory  nerve-trunks  terminating  in 
them,  and  with  efferent  or  motor  trunks  issuing  from  them ;  and  our  assurance, 
that  it  is  through  their  instrumentality  that  the  mind  is  affected  by  external 
impressions,  rests  upon  the  fact,  that  if  an  interruption  exist  in  the  transmission 
of  the  influence  to  which  those  changes  give  rise,  at  any  point  whatever  between 
the  periphery  and  the  central  ganglion,  those  impressions  are  not  felt;  whilst, 
conversely,  any  interruption  along  the  course  of  the  efferent  fibres,  prevents  the 
influence  of  psychical  states  from  producing  any  respondent  contractions  in  the 
muscles. — The  simplest  mode  in  which  the  Nervous  system  is  subservient  to 
mental  changes,  is  in  that  affection  of  the  consciousness  which  is  directly  conse- 
quent upon  external  impressions,  and  is  designated  as  sensation ;  and  the  part 
of  the  apparatus  in  which  this  conversion  is  effected,  is  termed  the  sensorium. 
We  shall  hereafter  see  that  this  "  sensorium"  probably  consists,  in  Man,  of  a 
number  of  distinct  ganglionic  centres,  each  of  which  is  the  instrument  of  some 
one  special  kind  of  sensorial  change.  From  these  sensory  ganglia,  also,  motor 
fibres  proceed  to  the  muscles ;  and  through  their  instrumentality,  movements 


350  OF   THE   PRIMARY   TISSUES    OF   THE   HUMAN  BODY. 

may  be  produced  by  the  reaction  of  the  ganglionic  centres  to  the  impressions 
made  upon  them.  Such  movements,  however,  being  only  called  forth  through 
the  intermediation  of  sensation,  are  distinguished  as  "  sensori-motor"  or  "  con- 
sensual."— Superadded  to  the  mere  sensorium,  however,  in  Man  and  all  the 
higher  animals,  we  find  certain  other  ganglionic  masses,  the  Cerebral  hemispheres, 
whose  functional  relation  to  the  operations  of  mind  is  yet  more  intimate ;  for 
these  appear  to  be  the  instruments  of  all  the  higher  psychical  operations,  the 
formation  of  ideas,  the  excitement  of  the  emotions,  the  acts  of  combination,  com- 
parison, and  judgment,  the  determinations  of  the  will,  &c.  They  receive  their 
first  stimulus  to  action,  not  from  impressions  transmitted  to  them  directly  from 
the  peripheral  organs,  but  from  an  agency  sent  up  to  them  from  the  sensorial 
centres;  and  it  seems  probably  to  be,  in  like  manner,  through  an  agency  reflected 
downwards  to  those  centres,  and  acting  through  their  instrumentality,  that  the 
influence  of  the  will,  of  emotional  states,  &c.,  is  transmitted  to  the  motor  appa- 
ratus.— Thus  we  see  that  the  nervous  force,  itself  excited  by  impressions  of  a 
physical  nature,  can  determine  mental  changes ;  whilst,  conversely,  certain  states 
of  mind,  by  exciting  the  nervous  force,  can  effect  changes  in  the  bodily  fabric, 
and,  through  this,  upon  the  external  objects  within  its  reach. 

352.  The  instrumentality  of  the  Nervous  system  is  not  limited,  however,  to 
the  excitation  of  mental  activity  on  the  one  hand,  or  to  that  of  muscular  con- 
traction on  the  other;  for  the  peculiar  agency  which  it  exerts  is  found  to  have 
an  intimate  relationship  with  all  the  other  manifestations  of  vital  force,  which 
the  animal  organism  exhibits.  So  intimate,  indeed,  is  this  relationship — so 
obvious  is  the  influence  which  nervous  agency  exerts  over  the  operations  of  Nu- 
trition, Secretion,  &c.,  especially  in  the  higher  animals — that  many  physiologists 
have  regarded  them  as  essentially  dependent  upon  it.  For  this  assumption, 
however,  there  is  no  valid  evidence;  and  the  whole  tendency  of  recent  discovery 
has  been  (as  we  have  seen)  to  establish  the  doctrine  of  the  essential  independence 
of  the  vital  endowments  of  each  integral  part  of  the  fabric.  And  all  the 
phenomena  which  have  been  supposed  to  indicate  the  necessity  for  nervous 
agency,  as  a  condition  of  acts  of  growth,  development,  &c.,  are  equally  expli- 
cable upon  the  doctrine  here  advocated,  which  affords  a  definite  scientific  ex- 
pression of  them.  For,  just  as  Electricity,  developed  by  Chemical  change,  may 
operate  (by  its  correlation  with  chemical  affinity)  in  producing  other  chemical 
changes  elsewhere — so  may  Nerve-force,  which  has  its  origin  in  Cell-formation, 
excite  or  modify  the  process  of  cell-formation  in  other  parts,  and  thus  influence 
all  the  vital  manifestations  of  the  several  tissues,  whatever  may  be  their  own 
individual  characters.  This  expression  is  also  available  for  the  well-known  in- 
fluence of  mental  states  upon  the  properties  of  the  various  tissues  and  the  com- 
position of  the  secretions;  since  this  influence  can  only  be  exerted  through  the 
instrumentality  of  the  nervous  apparatus. — Further,  it  not  only  appears  that  a 
simple  withdrawal  or  disturbance  of  the  nervous  force  supplied  to  particular 
organs,  occasions  a  retardation  or  perversion  of  their  vital  operations ;  but  there 
also  seems  evidence  that  an  influence  of  an  opposite  kind  may  be  transmitted 
through  the  nervous  system,  which  is  positively  and  directly  antagonistic  to  the 
exercise  of  the  vital  powers  of  the  several  tissues.  Such,  at  least,  appears  to 
be  the  only  legitimate  mode  of  accounting  for  the  extraordinary  effect  of  "a 
shock,"  physical  or  mental,  in  at  once  and  completely  destroying  the  contrac- 
tility of  the  heart,  and  in  bringing  to  a  stand  the  vital  operations  of  other  parts 
(§  321).  And  it  harmonizes  well  with  the  fact  that,  in  Hemiplegia,  the  "  palsy- 
stroke"  transmitted  from  the  brain  along  the  spinal  cord,  almost  invariably  affects 
the  leg  less  injuriously  than  the  arm,  and  for  a  shorter  duration;  recovery  tak- 
ing place  soonest  in  the  leg,  even  when  it  has  been  at  first  paralyzed  as  com- 
pletely as  the  arm.  If  the  Nervous  force  be  regarded  as  a  polar  force  (§  364, 


FUNCTIONS   OF   NERVOUS    TISSUE.  351 

note),  analogous  in  its  mode  of  transmission  to  Electricity,  it  is  not  difficult  to 
understand  that  the  reversal  of  the  usual  direction  of  its  action  may  produce 
the  effects  in  question ;  especially  when  it  is  borne  in  mind,  that  the  direct  and 
inverse  electric  currents  (as  shown  by  Prof.  Matteucci)  exert  opposite  influences 
upon  the  nervous  excitability.1 

353.  The  manifestations  of  nerve-force  are  almost  invariably  excited  by  the 
agency  of  stimuli,  which  operate  upon  the  peripheral  origins  of  the  afferent 
nerves,  and  upon  the  central  origins  of  the  efferent.  In  the  cases  already  re- 
ferred to,  the  stimulus  whose  influence,  conveyed  to  the  central  gangalia,  excited 
sensations  or  respondent  movements,  was  that  of  mechanical  Motion;  and  this 
is  equally  effectual  when  applied  to  the  trunks  of  the  afferent  nerves,  as  by 
pinching  or  pricking  them.  But  other  physical  agencies  produce  corresponding 
results.  Thus  Neat,  applied  to  a  sensory  surface,  excites  the  nerve-force  of  the 
afferent  nerves,  by  whose  instrumentality  such  a  change  is  produced  in  the  sen- 
sorial  centres,  as  renders  us  conscious  of  the  external  alteration.  The  power  of 
Light,  moreover,  to  excite  nerve-force,  is  clearly  indicated  by  its  influence  upon 
the  optic  nerve  through  the  instrumentality  of  the  retina.3  So,  again,  the  stimu- 
lating agency  of  Chemical  Affinity  is  made  apparent  by  the  pain  which  results 
from  the  application  of  strong  reagents  to  the  extremities  or  to  the  trunks  of 
the  sensory  nerves.  But  of  all  the  physical  forces,  Electricity  has  the  most 
powerful  influence  in  exciting  nerve-force,  and  seems  to  have  the  most  direct  re- 
lation to  it.  If  an  electric  current  be  made  to  pass  far  a  short  distance  only 
along  the  trunk  of  a  sensory  nerve,  or  through  its  peripheral  ramifications,  it 
excites  in  the  sensorium  the  peculiar  sensations  produced  by  ordinary  impres- 
sions conveyed  through  that  nerve;  so,  again,  if  the  current  be  transmitted  for 
however  short  a  space  through  a  motor  nerve,  it  excites  contractions  in  the  mus- 
cles which  are  supplied  from  its  branches.  It  was  formerly  supposed  that  the 
electricity  was  the  immediate  cause  of  the  changes  thus  induced  in  the  senso- 
rium or  in  the  muscular  apparatus ;  but  it  has  been  clearly  proved  that  such  is 
not  the  case,  the  passage  of  the  current  along  a  portion  of  the  trunk  being  suffi- 
cient to  excite  the  nerve-force  in  the  remainder. — On  the  other  hand,  we  have 
adequate  proof  that  the  force  transmitted  from  the  central  ganglia  to  the  muscles, 
is  of  the  same  nature  with  the  preceding;  for  all  the  stimuli  which  excite  sen- 
sations when  applied  to  the  trunks  of  the  afferent  nerves,  excite  motions  when 
applied  to  the  trunks  of  the  efferent.  This  force  seems  to  be  developed  by 
changes  which  take  place  in  the  vesicular  matter  of  those  ganglia  (§§  357 — 362); 
but  the  stimulus  to  that  development  may  be  of  two  very  different  kinds.  For, 
on  the  one  hand,  the  "  motor  impulse"  (as,  for  the  sake  of  convenience,  it  may 
be  designated)  may  be  excited  by  a  change  originating  in  any  part  of  the  body, 
and  transmitted  to  the  ganglion  through  the  afferent  nerves;  as  in  "reflex" 
actions  of  various  kinds.  But,  on  the  other,  it  may  be  called  forth  by  an 
agency  purely  mental,  which  acts  directly  upon  the  vesicular  matter  of  the  gan- 
glion, producing  movements  whose  source  is  thus  not  peripheral,  but  central. 

1  The  direct  current  is  that  which  is  transmitted  along  a  motor  nerve  in  the  direction  of 
its  ramifications ;  the  inverse,  that  which  is  transmitted  from  the  periphery  towards  the 
centre.     The  "direct"  current  rapidly  weakens  and  at  last  destroys  the  excitability  of  a 
nerve ;  so  that,  when  it  has  traversed  the  lumbar  nerve  of  a  frog  for  twenty  or  thirty 
minutes,  there  are  no  further  contractions,  either  on  opening  or  closing  the  circuit.     On 
the  other  hand,  the  passage  of  the  "inverse"  current  augments  the  excitability  within 
certain  limits ;  and  restores  that  which  has  been  exhausted  by  the  direct  current.     (See 
Prof.  Matteucci's  "Lectures  on  the  Physical  Phenomena  of  Living  Beings,"  translated  by 
Dr.  Pereira,  p.  242,  Am.  Ed.} 

2  It  seems  to   be  the  want  of  this  intermediate  ganglionic  apparatus  (g  343),  which 
prevents  Light  from  acting  upon  the  trunks  of  the  sensory  and  motor  nerves,  after  the 
manner  of  Heat. 


352  OF   THE   PRIMARY   TISSUES   OF   THE   HUMAN   BODY. 

And  in  states  of  peculiar  functional  activity  of  the  nervous  centres  (such  as  that 
produced  in  the  spinal  cord  by  the  administration  of  strychnine),  it  would  appear 
as  if  motor  impulses  originate  spontaneously,  just  like  certain  muscular  contrac- 
tions (§  328);  how  far  this  must  be  accounted  a  normal  modus  operandi,  how- 
ever, is  yet  uncertain. 

354.  The  influence  of  excitants,  repeatedly  and  powerfully  applied  to  the 
Nervous  tissue,  is  undoubtedly  (as  in  the  case  of  Muscle)  to  weaken,  and  at  last 
to  exhaust,  its  power  of  responding  to  them ;  this  is  seen  alike  in  experimental 
researches,  and  in  the  ordinary  course  of  vital  action  (§  360).     The  excitability 
thus  exhausted,  can  only  be  regained  by  an  interval  of  repose,  during  which  the 
nutritive  operations  may  restore  the  tissue  to  its  pristine  integrity,  and  thus 
prepare  it  for  renewed  activity. — On  the  other  hand,  the  moderate  and  regular 
excitation  of  Nervous  activity,  with  due  intervals  of  repose,  is  favorable  to  its 
nutrition ;  and  this  is  especially  to  be  noticed  in  the  case  of  the  Brain,  an  in- 
creased development  of  which,  especially  in  young  subjects,  is  continually  to  be 
noticed  as  consequent  upon  the  continuance  of  a  state  of  high  functional  activity. 
It  seems  probable  that  this  augmentation  is  principally  due,  as  in  the  case  of 
Muscle,  to  the  increased  afflux  of  blood  to  the  organ,  which  its  functional  activity 
induces.     That  the  interruption  of  that  activity  not  only  suspends  nutrition,  but 
rapidly  induces  degenerative  change,  has  been  already  shown  (§  347). 

355.  Of  the  condition  on  which  the  functional  activity  of  the  Nervous  system 
is  dependent,  the  first  H,  of  course,  the  integrity  of  its  own  structure ;  thus,  an 
interruption  in  any  part  of  the  "nervous  circle"  will  prevent  the  manifestation 
of  its  peculiar  endowments.     But,  however  perfect  and  complete  its  condition, 
no  action  can  take  place  in  it  without  a  supply  of  oxygenated  blood ;  which  is 
more  immediately  necessary  for  the  maintenance  of  the  Nervous  power,  than  it 
is  for  that  of  any  other  tissue  whatever.     That  this  supply  is  not  so  essential, 
however,  to  the  conduction  of  impressions,  as  it  is  to  their  reception  and  reflexion, 
would  appear  alike  from  the  difference  between  the  amounts  of  blood  transmitted 
to  the  trunks  of  the  nerves  in  their  course,  and  to  their  peripheral  and  central 
terminations ;  and  from  the  different  effects  of  the  suspension  of  the  circulation 
upon  each.     For   the   nerve-trunks  are   not   peculiarly   vascular,    and   retain 
their  power  of  transmission  for  some  time  after  the  movement  of  the  blood  has 
ceased.     On  the  other  hand,  both  the  nervous  centres  and  the  organs  of  sense 
receive  an  enormous  supply  of  blood;  and  the  effects  of  its  interruption  are  imme- 
diately manifested  in  the  most  striking  manner.     Thus,  if  the  circulation  through 
the  Brain  be  suspended  but  for  an  instant,  insensibility  and  loss  of  voluntary 
power  supervene,  and  continue  until  it  is  restored;  as  was  shown  in  the  follow- 
ing experiment  by  Sir  A.  Cooper.     After  having  tied  both  carotid  arteries  in  a 
dog,  he  compressed  the  Vertebral  trunks ;  and  immediate  insensibility  came  on, 
the  animal  at  the  same  time  falling  powerless.     But  convulsive  movements  oc- 
curred at  the  same  time ;  showing  that  the  functions  of  the  spinal  cord  were 
not  suspended,  but  only  deranged.     As  soon  as  the  blood  was  readmitted  to 
the  brain,  the  animal  recovered  it  consciousness  and  voluntary  power,  and  stood 
on  its  legs  again ;   the  convulsive  movements  ceasing  at  the  same  time.1 — In 
Syncope,  moreover,  the  circulation  through  the  Spinal  cord  is  weakened,  by  the 
failure  of  the  heart's  action,  to  the  same  extent  as  the  flow  of  blood  through  the 
Brain  ;  and  a  general  cessation,  not  merely  of  muscular  movement,  but  of  all 
power  of  exciting  it,  is  the  immediate  result.     No  sooner,  however,  is  the  circu- 
lation fully  re-established,  than  the  power  of  the  Nervous  centres  is  restored. — 
Again,  the  influence  of  diminished  circulation  at  the  origins  of  the  afferent  nerves, 
is  shown  in  the  deficient  impressibility  of  these  nerves  at  the  part  affected.     Thus, 
if  the  movement  of  blood  through  the  capillaries  of  a  limb  be  stagnated  (whether 

"  '  Guy's  Hospital  Reports,"  vol.  i. 


FUNCTIONS    OF   NERVOUS   TISSUE.  353 

by  pressure  on  the  arterial  trunks,  by  cold,  or  by  any  other  cause),  the  check 
is  at  once  made  apparent  by  the  numbness  of  the  surface;  and  a  complete 
stagnation  produces  complete  insensibility.  The  power  of  receiving  impressions 
which  excite  reflex  movements,  is  diminished  in  the  same  degree. 

356.  On  the  other  hand  it  is  found,  that  increased  circulation  through  the 
same  parts  is  attended  with  an  exaltation  of  their  function.     This  is  particularly 
noticed  in  those  affections  of  the  brain  and  spinal  cord,  closely  bordering  on  in- 
flammation, to  which  the  terms  active  congestion  and  determination  of  blood  have 
been  applied.     We  have,  in  such  cases,  extreme  acuteness  of  sensation,  excessive 
activity  of  the  mental  functions,  or  violent  excitement  of  the  motor  powers;  accord- 
ing (it  would  seem)  to  the  particular  division  of  the  nervous  centres  most  affected. 
— Again,  we  find  that  an  increase  in  the  circulation  through  any  organ  from 
which  afferent  nerves  arise,  increases  their  readiness  to  receive  impressions;  thus 
the  sensibility  of  the  genital  organs  of  animals  during  the  period  of  heat,  and 
of  those  of  man  in  a  state  of  venereal  excitement,  are  greatly  augmented ;  and 
the  tendency  of  impressions  made  upon  them  to  excite  reflex  movement,  is  simi- 
larly exalted. 

357.  The  due  activity  of  the  Nervous  System  is  not  merely  dependent  upon 
a  constant  and  ample  supply  of  Blood ;  but  it  requires  that  this  blood  should 
be  in  a  state  of  extreme  purity,  and  more  especially  that  it  should  contain  a 
due  supply  of  oxygen,  and  should  be  depurated  of  its  carbonic  acid,  and  of  other 
products  of  the  decomposition  of  the  body.     The  final  cessation   of  nervous 
power,  in  death  by  Asphyxia,  is  partly  due  (as  will  be  shown  hereafter,  CHAP. 
x.  SECT.  3),  to  a  positive  deficiency  in  the  supply  of  blood ;  but  the  obtuseness 
of  sensibility  which  gradually  increases  until  a  state  of  unconsciousness  comes 
on,  may  be  clearly  traced  in  the  first  instance  to  the  deficient  aeration  of  the 
blood,  which  is  gradually  deprived  of  its  oxygen,  and  more  and  more  charged 
with  carbonic  acid.     Corresponding  but  less  severe  symptoms  occur,  when  the 
excretion  of  carbonic  acid  is  not  checked,  but  only  slightly  impeded,  provided 
the  impediment  be  in  operation  for  a  sufficient  length  of  time,  as  in  the  case  of 
an  ill-ventilated  apartment ;  an  indisposition  to  mental  exertion,  a  deficiency  of 
muscular  power,  and  an  obtuseness  of  the  intellectual  and,  moral  faculties,  being 
the  general  result. — The  retention  of  other  excrementitious  products  in  the 
Blood  is  not  less  injurious,  though  its  operation  is  less  rapid.     Thus,  when  the 
elimination  of  Biliary  matter  is  prevented,  so  that  the  blood  becomes  unduly 
charged  with  its  components,  a  great  deficiency  of  Nervous  power  is  manifested; 
the  general  sensibility  being  rendered  obtuse,  the  mental  operations  becoming 
torpid,  and  the  motor  energy  enfeebled ;  and  this  state  may  become  more  and 
more  intense,  with  the  increase  of  the  accumulation,  until,  as  in  Asphyxia,  the 
entire  functional  activity  of  the  Nervous  system  becomes  extinct.     The  effect  of 
the  retention  of  the  materials  of  the  Urinary  excretion  is  not  very  dissimilar ; 
but  with  the  gradually  deepening  Coma,  there  are  usually  (as  in  Asphyxia) 
convulsive  movements. — The  influence  of  various  poisons  introduced  into  the 
blood  ab  extra,  upon   the  functional  activity  of  the  Nervous  system,  exhibits 
hi  a  very  marked  manner  the  extreme  importance  of  the  purity  of  the  circulat- 
ing fluid,  to  the  normal  performance  of  the  duties  of  this  most  important  appa- 
ratus.    Thus  we  find  the  action  of  one  class  of  poisons  to  commence  with  the 
disturbance  of  the  mental  powers ;  the  control  exercised  by  the  will  over  the 
course  of  thought  is  weakened,  incoherence  succeeds  to  regularity,  passion  takes 
the  place  of  calmness,  and  the  state  at  last  becomes  one  of  maniacal  delirium. 
Another  class  acts  primarily  on  the  sensorial  powers ;  the  consciousness  of  ex- 
ternal impressions  being  first  rendered  obtuse,  and  then  entirely  destroyed;  and 
all  the  movements  which  are  ordinarily  excited  or  guided  by  it,  being  conse- 
quently checked.     And  a  third  class  operates  especially  upon  the  motor  portion 
of  the  nervous  apparatus ;  inducing  an  extraordinary  degree  of  excitability  in 

23 


354  OF   THE   PRIMARY    TISSUES    OF    THE    HUMAN   BODY. 

that  portion  of  the  central,  organs  which  responds  to  the  action  of  stimuli;  or, 
on  the  other  hand,  diminishing  the  normal  excitability,  to  such  a  degree  that 
not  only  the  ordinary  stimuli,  but  excitants  of  unusual  potency,  occasion  no  re- 
sponse.— We  shall  hereafter  see  (CHAP.  xiv.  SECT.  7)  that  there  is  a  very  strong 
probability,  that  a  large  proportion  of  the  disordered  actions  of  the  Nervous 
System  depend  upon  the  presence  of  poisonous  matters  in  the  blood,  which  have 
not  been  introduced  from  without,  but  have  been  generated  within  the  system 
itself. 

358.  All  that  we  know  respecting  the  conditions  on  which  the  production  of 
Nervous  Force  is  dependent,  supports  the  belief  that  its  evolution  involves  a 
change  of  composition  in  the  Nervous  matter;  this  change  essentially  consisting 
in  the  cessation  of  its  existence  as  a  living  tissue,  and  in  the  combination  of 
oxygen  with  its  constituents;  so  that,  in  their  restoration  to  the  condition  of 
inorganic  matter,  the  Vital  force  which  was  previously  operative  in  the  growth 
and  development  of  the  tissue,  is  set  free  under  this  peculiar  form.     It  may 
serve  to  render  this  doctrine  more  intelligible,  if  we  again  refer  to  the  analogy 
of  the  Galvanic  battery ;  in  which  the  change  in  the  condition  of  the  zinc  (or 
other  oxidizable  metal),  which  ceases  to  exist  as  such,  and  which  enters  into 
new  chemical  combinations,  is  the  condition  of  the  evolution  of  the  electric 
force. — The  chief  grounds  for  this  doctrine  will  now  be  enumerated. 

359.  In  the  first  place,  the  dependence  of  Nervous  energy  upon  the  constant 
circulation  of  Blood  through  the  tissue,  is  much  more  close  and  immediate,  than 
can  be  accounted  for  on  the  idea  that  the  relation  is  one  of  mere  nutrition  or 
development.     On  the  contrary,  where  these  last  changes  are  taking  place  most 
actively,  we  often  find  rather  a  disposition  to  stagnation  of  the  current,  to  give 
time  for  the  elaboration  of  the  nutrient  materials  that  are  to  be  withdrawn  from 
it ;  and  in  no  case  does  the  process  so  instantaneously  cease,  when  the  flow  is 
suspended.     From  this  it  would  appear,  that  a  reaction  takes  place  between  the 
elements  of  the  Nervous  tissue  and  some  material  supplied  by  the  Blood,  which 
is  much  more  rapid  in  its  character  than  the  process  of  cell  development,  and 
which  is  essentially  concerned  in  the  production  and  maintenance  of  the  nervous 
activity.     That  the  material  supplied  by  the  blood  for  this  purpose  is  Oxygen, 
would  appear  from  a  variety  of  considerations.    A  general  survey  of  the  Animal 
kingdom  shows,  that  oyxgen  is  essential  to  the  maintenance  of  animal  life,  as 
distinct  from  vegetative ;  and  a  more  particular  comparison  of  different  tribes 
demonstrates  most  unequivocally,  that  the  consumption  of  oxygen  is  in  direct 
relation  to  the  development  of  the  animal  powers  in  each.1     The  effects  of  a  sus- 
pension of  the  oxygenating  process  (§357)  completely  harmonize  with  these  facts. 

360.  Further,  in  proof  that  the  activity  of  the  Nervous  system  is  immediately 
dependent  not  upon  a  process  of  development  or  nutrition,  but  upon  one  of  dis- 
integration or  destruction,  it  may  be  urged,  that  it  is  impossible  for  this  state 
of  activity  to  be  maintained  in  a  large  portion  of  it,  without  an  interval  of  re- 
pose, which  we  know  to  be  favorable  to  the  vegetative  or  reparative  processes. 
It  is  true  that  there  are  certain  portions  of  it,  particularly  those  that  put  in  ac- 
tion the  respiratory  muscles,  which  are  in  a  state  of  unceasing  though  moderate 
activity;  and  in  these,  the  constant  nutrition  is  sufficient  to  repair  the  effects  of 
the  constant  decay.     But  those  parts  which  operate  in  a  more  powerful  and 
energetic  manner,  and  which  are  therefore  more  rapidly  disintegrated  when  in 
action,  need  a  season  of  rest  for  their  reparation.     Hence  the  sense  of  fatigue 
which  is  experienced,  when  the  Mind  has  been  long  acting  through  its  instru- 
ment, the  Brain  ;3  and  the  irresistible  tendency  to  sleep,  which  usually  super- 

1  See  "Princ.  of  Phys.,  Gen.  and  Comp.,  CHAP,  xin.,  Am.  Ed. 

2  Of  the  sense  of  fatigue  induced  by  continued  muscular  exertion,  it  is  difficult  to  say 
how  much  is  attributable  to  the  state  of  the  Muscles  themselves  ;  it  is  better,  therefore,  to 
base  this  statement  upon  cases  in  which  the  activity  is  purely  Nervous. 


FUNCTIONS   OF   NERVOUS    TISSUE.  355 

venes  after  any  unusual  exertion  of  this  kind.  In  the  healthy  state  of  the  body, 
when  the  exercise  of  the  Nervous  system  by  day  does  not  exceed  that  which  the 
rejtose  of  the  night  may  compensate,  the  nutritive  operations  maintain  it  in  a 
condition  which  fits  it  for  constant  moderate  exercise ;  but  unusual  demands  upon 
its  activity — whether  by  long-continued  and  severe  exercise  of  the  intellect,  by 
excitement  of  the  emotions,  or  by  the  combination  of  both,  in  that  state  of 
anxiety  which  the  circumstances  of  man's  condition  too  frequently  induce — oc- 
casion an  unusual  "  waste/7  and  require  a  prolonged  repose  and  uninterrupted 
nutrition,  for  the  complete  restoration  of  its  powers.  There  can  be  no  doubt  that 
(from  causes  which  are  not  known)  the  amount  of  Sleep  required  by  different 
persons,  for  the  maintenance  of  a  healthy  condition  of  the  nervous  system,  varies 
considerably ;  some  being  able  to  dispense  with  it,  to  a  degree  which  would  be 
exceedingly  injurious  to  other  individuals,  who  do  not  surpass  them  in  mental 
activity.  Where  a  prolonged  exertion  of  the  mind  has  been  made,  and  the  na- 
tural tendency  to  sleep  has  been  habitually  resisted  by  a  strong  effort  of  the  will, 
injurious  results  are  sure  to  follow.  The  bodily  health  breaks  down;  and  too 
frequently  the  mind  itself  is  permanently  enfeebled.  It  is  obvious  that  the  Nu- 
trition of  the  nervous  system  becomes  completely  deranged;  and  that  the  tissue  is 
no  longer  formed,  in  a  manner  requisite  for  the  discharge  of  its  healthy  functions. 
The  same  may  be  said  of  the  state  of  Mania  \  in  which  there  is,  for  a  time,  an 
extraordinary  degree  of  activity  (though  manifested  in  an  irregular  manner)  of 
the  cerebral  functions,  and  in  absence  of  disposition  to  sleep.  Such  a  state  may 
continue  for  some  weeks ;  but  the  subsequent  exhaustion  of  nervous  power  is 
proportioned  to  the  duration  of  the  excitement,  and  frequent  attacks  of  mania 
almost  invariably  subside  at  last  into  Imbecility. 

361.  Additional  evidence  for  the  belief  that  the  functional  activity  of  the 
Nervous  tissue  involves  disintegration  of  its  tissue  by  the  agency  of  Oxygen,  is 
found  in  the  increase  of  alkaline  phosphates  in  the  urine,  when  there  has  been 
any  unusual  demand  upon  the  nervous  power.  No  others  of  the  soft  tissues 
contain  any  large  amount  of  phosphorus ;  and  the  marked  increase  in  these 
deposits,  which  has  been  continually  observed  to  accompany  long-continued  wear 
of  mind  (whether  by  intellectual  exertion,  or  by  the  excitement  of  the  feelings), 
and  which  follows  any  temporary  strain  upon  its  powers,  may  fairly  be  attributed 
to  this  cause.  The  most  satisfactory  proof  is  to  be  found  in  cases  in  which  there 
is  a  periodical  demand  upon  the  mental  powers ;  as,  for  example,  among  Clergy- 
men, in  the  preparation  for  and  discharge  of  their  Sunday  duties.  This,  when 
the  demand  for  mental  exertion  is  severe,  and  especially  when  there  is  that  state 
of  excitability  of  the  nervous  system  which  is  frequently  coexistent  with  a  dimi- 
nution of  its  vigor,  is  found  to  be  very  commonly  followed  by  the  appearance  of 
a  large  quantity  of  the  alkaline  phosphates  in  the  urine.  And  in  cases  in  which 
constant  and  severe  intellectual  exertion  has  impaired  the  nutrition  of  the  brain, 
and  has  consequently  weakened  the  mental  power,  it  is  found  that  any  prema- 
ture attempt  to  renew  the  activity  of  its  exercise,  causes  the  reappearance  of  the 
excessive  phosphatic  discharge,  indicative  of  an  undue  "waste"  of  nervous 
matter.1  Further,  it  has  been  shown  by  Dr.  Bence  Jones,2  that  acute  affections 
of  nervous  substance,  both  organic  and  functional,  are  generally  attended  with 
an  increase  in  the  phosphatic  salts  of  the  urine ;  the  amount  of  phosphates,  in 
acute  inflammation  of  the  brain,  seeming  to  be  proportional  to  the  intensity  of 
the  inflammation,  and  in  various  forms  of  disordered  action  (delirium  tremens, 

1  The  Author  has  known  more  than  one  case  of  this  kind,  occurring  among  young  men 
whose  anxiety  for  distinction  had  induced  them  to  go  through  an  excessive  amount  of  intel- 
lectual labor  during  their  Student-life,  and  who  found  themselves  forced  to  pay  the  penalty 
of  that  excess,  in  a  subsequent  prolonged  abstinence  from  all  mental  occupation  involving 
the  slightest  degree  of  effort. 

2  "Philosophical  Transactions,"  1846. 


356  OF   THE   PRIMARY   TISSUES   OF   THE    HUMAN    BODY. 

however,  constituting  a  marked  exception),  to  the  degree  of  mental  disturbance . 
— There  are,  however,  many  other  sources  of  increase  in  the  phosphatic  compo- 
nents of  the  urine ;  and  hence  it  is  only  when  these  are  excluded  or  allowed  for, 
that  the  increase  attributable  to  "  waste'7  of  Nervous  tissue  can  be  estimated.1 

362.  The  rapid  disintegration  of  Nervous  tissue,  when  in  a  state  of  functional 
activity,  is  further  indicated  by  the  demand  for  aliment  which  this  creates;  for 
every  one  who  has  been  accustomed  to  habits  of  sustained  mental  exertion,  must 
be  conscious  that,  where  the  general  health  is  good,  the  appetite  for  food  is  no 
less  engendered  by  such  labour,  than  it  is  by  the  exertion  of  the  muscular  powers. 
Further,  as  already  pointed  out,  there  are  appearances  in  the  Nervous  tissue 
itself,  which  indicate  that  nutritive  changes  are  continually  in  progress  in  ite 
substance  (§  346) ;  and  the  rapidity  with  which  it  undergoes  alteration  when  its 
functional  operations  are  suspended,  is  an  additional  indication  of  the  activity 
of  the  changes  of  composition  (of  however  different  a  nature  such  may  be)  which 
those  operations  involve. 

363.  In  all  that  has  been  said  on  this  subject,  reference  has  been  especially 
made  to  the  " vesicular"  element  of  the  Nervous  centres;  for  in  regard  to  the 
"  fibrous"  component  of  the  nerve-trunks,  which  is  a  mere  conductor  of  the  force 
generated  there,  the  evidence  of  continual  change  is  not  of  a  kind  to  justify  any 
such  assumption.     In  fact,  there  would  appear  to  be  strong  reasons  for  believing 
that  the  amount  of  "  waste"  which  it  undergoes  in   the  discharge  of  this  office 
is  comparatively  trifling  (§  355). 

364.  Of  the  actual  nature  of  the  changes,  by  which  impressions  are  received 
upon  the  peripheral  origins  of  the  afferent  nerves,  or  are  communicated  to  the 
central  origins  of  the  motor,  and  by  which  they  are  conducted  along  each  to 
their  opposite  extremities,  Physiologists  have  no  certain  knowledge.     That  they 
are  Electrical  in  their  character,  has  been,  and  still  continues  to  be,  a  favourite 
theory  with  some ;  and  the  idea  seems  to  derive  support  from  the  marked  degree 
in  which  Electricity,  transmitted  along  the  Nervous  trunks,  can  excite  the 
changes  to  which  those  nerves  are  ordinarily  subservient.     Thus,  a  feeble  gal- 
vanic current,  transmitted  along  the  motor  nerves  of  an  animal  recently  killed, 
will  call  the  muscles  supplied  by  it  into  contraction;  whilst,  on  the  other  hand, 
a  similar  current  transmitted  along  an  afferent  nerve,  shall  excite  reflex  move- 
ments through  its  ganglionic  centre.     Further,  if  the  current  be  transmitted 
along  an  afferent  nerve,  in  a  living  animal,  it  will  excite  sensations  which  are 
referred  to  the  part  whence  the  nerve  arises;  and,  as  will  be  shown  hereafter 
(CHAP.  xv.  SECT.  1),  Electricity  is  capable  of  thus  producing  sensations  of  a 
special  kind,  as  well  as  those  of   a  general  nature.     Moreover,  in  the  instanta- 
neousness  of  the  transmission  of  Nervous  agency  from  one  part  of  the  system 
to  another,  there  is  more  analogy  to  Electricity,  than  to  any  other  known  force. 
But  these  and  bimilar  arguments  do  not  prove  the  identity  of  Nervous  agency 
with  Electricity;  since  the  effects  of  the  former  may  be  imitated  to  a  certain  ex- 
tent, not  merely  by  Electricity,  but  by  mechanical  and  chemical  stimulation  of 
various  kinds. — Further,  there  are  powerful  arguments  against  such  a  suppo- 
sition, the  validity  of  which  cannot  be  easily  set  aside.     All  attempts  to  prove 

1  Thus,  a  considerable  amount  of  phosphates,  alkaline  as  well  as  earthy,  passes  into  the 
urine  directly  from  the  food,  without  ever  becoming  part  of  the  living  tissue  ;  so  that,  if 
food  be  withheld,  there  is  an  immediate  diminution  in  the  quantity  which  the  urinary  secre- 
tion contains — a  consideration  of  special  importance  in  studying  the  influence  of  acute 
diseases,  in  which  the  quantity  of  aliment  taken  is  very  small.  So,  again,  there  are  various 
disordered  states  of  the  digestive  system,  in  which  there  is  an  excess  of  phosphates  in  the 
urine,  without  any  coincident  indication  of  excessive  "waste"  of  nervous  tissue.  More- 
over, the  deposit  of  phosphatic  salts  is  by  no  means  an  adequate  indication  of  their  presence 
in  excess;  since  their  insolubility  may  depend  upon  conditions  altogether  different. — See 
especially  Dr.  Golding  Bird's  treatise  on  ''Urinary  Deposits/'  <'IIAJ».  x.,  Am.  Ed. 


FUNCTIONS   OF   NERVOUS   TISSUE.  357 

the  existence  of  an  Electric  current,  in  a  Nervous  trunk  that  is  actually  engaged 
in  conveying  motor  influence,  have  completely  failed,  though  made  with  the 
greatest  precaution.  Thus,  Prof.  Matteucci  having  experimented  upon  the  very 
large  crural  nerve  of  a  Horse,  which  was  caused  by  stimulating  its  roots,  to 
throw  the  muscles  of  the  leg  into  violent  contraction,  nevertheless  found  that, 
although  he  used  instruments  of  such  delicacy  as  to  be  capable  of  detecting  an 
infinitesimally-small  disturbance  of  the  electric  equilibrium,  no  such  disturbance 
was  evident.1  Further,  it  is  well  known  that  the  conducting  power  of  the 
nerves  is  destroyed,  not  merely  by  dividing  the  trunk,  but  also  by  putting  a  liga- 
ture round  it ;  which  last  operation  does  not  diminish  its  powers  as  a  conductor 
of  Electricty.  Moreover,  the  various  fibrils  are  not  as  completely  insulated  from 
each  other  in  regard  to  Electricity,  as  we  know  them  to  be  with  respect  to  nerv- 
ous agency;  for  the  first  of  these  forces,  when  transmitted  along  a  nervous  trunk, 
cannot  be  restricted  to  any  fibre  or  fasciculus  of  fibres,  but  spreads  through  the 
entire  trunk,  and  even  to  the  neighboring  parts  in  which  it  is  imbedded;  whilst 
the  latter  is  continually  restricted  to  a  small  portion  of  the  trunk,  as  is  mani- 
fested by  its  results.  Again,  if  a  small  piece  of  a  nervous  trunk  be  cut  out,  and 
be  replaced  by  an  electric  conductor,  electricity  will  still  pass  along  the  nerve; 
but  no  nervous  force,  excited  by  stimulus  above  the  section,  will  be  propagated 
through  the  conductor  to  the  parts  below.  And  lastly,  the  conducting  power 
of  Nerve  for  Electricity  is  stated  by  Matteucci  to  be  not  more  than  one-fourth 
of  that  of  Muscle ;  whilst  Messrs.  Todd  and  Bowman  give  it  as  the  result  of  their 
experiments,  that  both  Nerve  and  Muscle  are  infinitely  worse  conductors  than 
copper ;  their  power  of  conduction  not  ranking  above  that  of  water  holding  in 
solution  a  small  quantity  of  saline  matter. 

365.  We  shall  probably  form  the  most  correct  idea  of  the  relation  which  sub- 
sists between  Electricity  and  Nervous  power,  by  regarding  it  as  of  the  same  kind 
as  that  which  subsists  between  Electricity  and  Heat  or  Magnetism.  For  as  a 
current  of  Electricity  passed  through  a  small  wire  generates  Heat,  and  Heat  ap- 
plied to  a  particular  combination  of  metals  generates  Electricity — or  as  an 
Electric  current  passed  round  a  bar  of  iron  renders  it  Magnetic,  whilst  con- 
versely the  Magnetic  force  will  generate  the  Electric — so  do  we  find  that  a  cur- 
rent of  Electricity,  passed  through  a  small  portion  of  a  motor  or  sensory  nerve, 
will  excite  the  Nervous  force  in  the  remainder;  whilst  there  seems  reason,  from 
the  phenomena  of  the  Electric  Fish,  to  consider  that  Nervous  force  may  in  its 
turn  generate  Electricity.  Hence  we  may  regard  them  as  closely  correlated, 
though  not  identical;2  and  this  idea  of  ''correlation"  we  seem  justified  in  ex- 
tending to  those  other  Physical  agencies,  which  have  been  shown  to  be  capable 
of  exciting  Nervous  force;  namely,  Heat,  Light,  Chemical  Affinity,  and  Me- 
chanical Motion.  For  there  is  adequate  ground  for  the  belief,  that  either  of  the 
three  former  may  be  excited  by  Nervous  agency,  although  its  most  obvious 
manifestation  is  the  production  of  movement;  and  that  thus,  as  each  of  these 
agencies  is  capable  of  developing  Nerve-force,  and  of  being  in  its  turn  developed 
by  it,  their  relationship  to  it  is  no  less  intimate  than  that  which  they  bear  to 
each  other,  although  a  more  special  apparatus  is  required  for  its  instrumental 
operation.  And  considering  that  Nerve-force  is  the  highest  of  all  the  mani- 
festations of  Vital  power,  alike  in  its  general  control  over  the  bodily  fabric,  and 

1  See  on  this  subject  Prof.  Matteucci' s  various  Memoirs  in  the  "  Philosophical  Trans- 
actions;" and  his  Lectures  on  the  Physical  Phenomena  of  Living  Beings"  (translated  by 
Dr.  Pereira),  p  259,  Am.  Ed. 

2  See  Prof.  Grove's  Treatise  "On  the  Correlation  of  the  Physical  Forces ;"  and  the  Au- 
thor's Memoir  "On  the  Mutual  Relations  of  the  Vital  and  Physical  Forces,"  in  the  "Phi- 
losophical Transactions"  for  1850. — This  doctrine  has  been  formally  adopted  by  Prof. 
Matteucci,  in  his  Eighth  Series  of  "Electro-Physiological  Researches,"  published  in  the 
"Philosophical  Transactions"  for  1850,  p.  296. 


358  GENERAL   VIEW   OF   THE   HUMAN    FUNCTIONS. 

in  its  relations  to  the  functions  of  the  Mind,  it  is  strikingly  confirmatory  of  the 
views  formerly  expressed  (CHAP.  in.  SECT.  2),  to  find  that  its  connection  with 
the  Physical  forces  is  so  peculiarly  intimate. 

a.  Although  for  the  sake  of  convenience,  Electricity  and  Nervous  power  are  spoken  of, 
here  and  elsewhere,  as  actual  entities  or  agents,  travelling  in  currents  along  the  wires  or 
cords  that  conduct  them,  it  must  not  be  forgotten  that  the  present  tendency  of  scientific 
inquiry  leads  us  to  abandon  such  an  idea,  in  the  former  case  at  least ;  what  is  commonly 
termed  the  transmission  of  electricity  being  the  result  of  a  molecular  change,  instantaneously 
occurring  along  the  whole  length  of  the  conducting  body,  in  virtue  of  a  disturbance  in  the 
polar  arrangement  of  its  particles,  at  one  extremity,  which  causes  a  similar  disturbance  to 
manifest  itself  at  the  other.  Thus,  if 

ab     ab     ab     ab     ab     ab     ab     ab 

represent  the  arrangement  of  the  particles,  in  the  condition  of  equilibrium  or  quiescence, 
and  this  condition  be  disturbed  at  one  extremity,  by  the  operation  of  a  new  attraction  upon 
the  first  particle  a,  a  new  arrangement  will  instantaneously  take  place  throughout :  this 
may  be  represented  by 

a     ba     ba     ba     ba     ba     ba     ba     b, 

which  shows  b  in  a  free  state  at  the  opposite  end,  ready  to  exert  its  influence  upon  any- 
thing submitted  to  it.  It  is  probable  that  in  this  respect  there  is  an  analogy  between  the 
Nervous  and  Electrical  forces;  and  that,  instead  of  speaking  of  the  "transmission  of 
Nervous  influence"  along  a  nerve,  we  should  describe  the  change  as  the  production  of  a 
"polar  state"  in  the  nervous  trunk ;  as  was  first  pointed  out  by  Messrs.  Todd  and  Bow- 
man ("Physiological  Anatomy,"  p.  220,  Am.  Ed.}. 


CHAPTER   VI. 

GENERAL  VIEWS  OF  THE  FUNCTIONS  OF  THE  HUMAN  BODY. 

1.    Of  the  Mutual  Dependence  of  its  Vital  Actions. 

366.  BY  the  study  of  the  various  forms  of  Elementary  Tissue  of  which  the 
Human  fabric  is  made  up,  we  are  led  to  the  very  same  conclusion  with  that 
which  we  draw  from  the  observation  of  the  simplest  forms  of  organized  being, 
or  from  the  scrutiny  into  the  earliest  condition  of  the  most  complex;  namely, 
that  the  simple  Cell  may  be  regarded  as  the  type  of  Organization  ;  and  that  on 
its  actions  rest  our  fundamental  idea  of  Life.  Between  the  humblest  Plant, 
and  the  embryonic  Human  organism,  there  is  originally  no  perceptible  differ- 
ence; they  may  be  said  to  have  a  common  starting-point;  and  the  subsequent 
difference  of  their  course  consists  essentially  in  this — that  the  successive  gene- 
rations of  cells,  which  are  the  descendants  of  the  former,  are  all  similar  to  it 
and  to  each  other,  each  cell  being  capable  of  maintaining  an  independent  ex- 
istence; whilst  the  subsequent  generations  which  originate  from  the  latter,  pro- 
gressively become  more  and  more  dissimilar  to  each  other,  and  more  and  more 
mutually  dependent;  so  that  whenever  it  is  thrown  entirely  upon  its  own  re- 
sources, the  integrity  of  the  whole  fabric  becomes  essential  to  the  continued  life 
of  any  individual  cell.  Every  individual  part,  however,  even  in  the  most  com- 
plex and  highly-organized  fabric,  has  its  own  capacity  of  development ;  and  the 
properties  which  it  possesses  are  the  result  of  its  exercise.  But  instead  of  the 
power  of  cell-growth  being  exerted,  as  in  the  Plant,  upon  the  inorganic  elements 
around,  it  can  only  be  put  in  action,  in  the  Animal,  upon  certain  peculiar  com- 


MUTUAL   DEPENDENCE    OF   THE   VITAL   ACTIONS.  359 

pounds,  having  the  same  chemical  composition  with  its  own  substance ;  and  it  is 
for  the  reception  of  these,  for  their  preparation,  and  for  their  maintenance  in 
the  requisite  state  of  purity,  that  a  large  part  of  the  fabric  of  the  Animal  is 
destined.  But  if  we  could  imagine  its  several  tissues  to  be  supplied  with  nutri- 
ment in  any  other  manner,  and  maintained  in  other  respects  in  their  normal 
circumstances  (as  regards  warmth,  air,  &c.),  we  have  every  reason  to  believe 
that  their  independent  vitality  would  manifest  itself  by  their  continued  devel- 
opment, and  by  the  regular  exhibition  of  their  ordinary  properties.  An  ap- 
proach to  this  condition  is  made,  in  the  experiment  of  entirely  detaching  a  limb 
from  the  body,  but  keeping  up  the  circulation  of  blood  through  it,  by  means  of 
tubes  connecting  its  main  artery  and  vein  with  those  of  the  stump.  Notwith- 
standing the  prejudicial  effect  of  such  severe  injuries,  the  persistence  of  the 
muscular  irritability  in  the  separated  part  (§  322),  is  a  sufficient  proof  of  the 
continuance  of  the  normal  actions  of  nutrition,  although  of  course  in  a  dimin- 
ished degree.  And  the  occasional  reunion  of  a  member  which  has  been  entirely 
separated,  when  decomposing  changes  have  not  yet  commenced  in  it,  most  clearly 
shows,  that  nothing  but  the  restoration  of  its  current  of  blood  is  requisite  for 
the  preservation  of  its  vitality,  and  that  its  powers  of  growth  and  renovation  are 
inherent  in  itself,  only  requiring  a  due  supply  of  the  nutrient  material,  with 
certain  other  concurrent  conditions. 

367.  In  every  living  structure  of  a  complex  nature,  therefore,  whilst  we  wit- 
ness a  great  variety  of  actions,  resulting  from  the  exercise  of  the  different  powers 
of  its  several  component  parts,  we  at  the  same  time  perceive  that  there  is  a  cer- 
tain harmony  or  co-ordination  amongst  them  all,  whereby  they  are  all  made  to 
concur  in  the  maintenance  of  the  Life  of  the  organism  as  a  whole.     And  if  we 
take  a  general  survey  of  them,  with  reference  to  their  mutual  relations  to  each 
other,  we  shall  perceive  that  they  may  be  associated  into  groups ;  each  consist- 
ing of  a  set  of  actions,  which,  though  different  in  themselves,  concur  in  effecting 
some  positive  and  determinate  purpose.     These  groups  of  actions  are  termed 
Functions.     Thus,  one  of  the  most  universal  of  all  the  changes  necessary  to  the 
continued  existence  of  a  living  being,  is  the  exposure  of  its  nutritious  fluid  to 
the  air ;  by  the  action  of  which  upon  it,  certain  alterations  are  effected.     For 
the  performance  of  this  aeration,  simple  as  the  change  appears,  many  provisions 
are  required.     In  the  first  place,  there  must  be  an  aerating  surface,  consisting 
of  a  thin  membrane,  permeable  to  gases ;  on  the  one  side  of  which  the  blood 
may  be  spread  out,  whilst  the  air  is  in  contact  with   the  other.     Then  there 
must  be  a  provision  for  continually  renewing  the  blood  which  is  brought  to  this 
surface ;  in  order  that  the  whole  mass  of  fluid  may  be  equally  benefited  by  the 
process.     And,  in  like  manner,  the  stratum  of  air  must  also  be  renewed,  as  fre- 
quently as  its  constituents  have  undergone  any  essential  change.     We  include, 
therefore,  in  speaking  of  the  "  function  of  respiration/'  not  only  the  actual 
aerating  process,  but  also  the  various  changes  which  are  necessary  to  carry  this 
into  effect,  and  which  obviously  have  it  for  their  ultimate  purpose. 

368.  On  further  examining  and  comparing  these  Functions,  we  find  that  they 
are  themselves  capable  of  some  degree  of  classification.     Indeed,  the  distinction 
between  the  groups  into  which  they  may  be  arranged,  is  one  of  essential  import- 
ance in  Animal  Physiology.     If  we  contemplate  the  history  of  the  Life  of  a 
Plant,  we  perceive  that  it  grows  from  a  germ  to  a  fabric  of  sometimes  gigantic 
size — generates  a  large  quantity  of  organized  structure,  as  well  as  many  organic 
compounds,  which  form  the  products  of  secretion,  but  which  do  not  undergo  or- 
ganization— and  multiplies  its  species,  by  the  production  of  germs  similar  to  that 
from  which  it  originated ;   but  that  it  performs  all  these  complex  operations, 
without  (so  far  as  we  can  perceive)  either  feeling  or  thinking,  without  conscious- 
ness or  will.     All  the  functions  of  which  its  Life  is  composed,  are,  therefore, 
grouped  together  under  the  general  designation  of  Functions  of  Organic  or  Ve- 


360  GENERAL   VIEW    OF   THE    HUMAN    FUNCTIONS. 

getative  life;  and  they  are  subdivided  into  those  concerned  in  the  development  and 
maintenance  of  the  structure  of  the  individual,  which  are  termed  functions  of  Nu- 
trition, and  those  to  which  the  Reproduction  of  the  species  is  due.  The  great  feat- 
ure of  the  Nutritive  operations  in  the  Plant,  is  their  constructive  character.  They 
seem  as  if  destined  merely  for  the  building  up  and  extension  of  the  fabric;  and  to 
this  extension  there  seems  in  some  cases  to  be  no  determinate  limit.  But  it  is  very 
important  to  remark,  that  the  growth  of  the  more  permanent  parts  of  the  struc- 
ture is  only  attained  by  the  continual  development,  decay,  and  renewal  of  parts, 
whose  existence  is  temporary.  No  fact  is  better  established  in  Vegetable  Phy- 
siology, than  the  dependence  of  the  formation  of  wood  upon  the  action  of  the 
leaves.  It  is  in  their  cells  that  those  important  changes  are  effected  in  the  sap, 
by  which  it  is  changed  from  a  crude  watery  fluid,  containing  very  little  solid 
matter,  to  a  viscid  substance  including  a  great  variety  of  organic  compounds, 
destined  for  the  nutrition  of  the  various  tissues.  The  "fall  of  the  leaf"  results 
merely  from  the  death  and  decay  of  its  tissue ;  as  is  evident  from  the  fact  that, 
for  some  time  previously,  its  regular  functions  cease,  and  that,  instead  of  a  fixa- 
tion of  carbon  from  the  atmosphere,  there  is  a  liberation  of  carbonic  acid  (a  result 
of  their  decomposition)  in  large  amount.1  Now  this  process  takes  place  no  less 
in  " evergreens"  than  in  " deciduous"  trees;  the  only  difference  being,  that  the 
leaves  in  the  latter  are  all  cast  off  and  renewed  together,  whilst  in  the  former 
they  are  continually  being  shed  and  replaced,  a  few  at  a  time.  It  appears  as  if 
the  nutritious  fluid  of  the  higher  Plants  can  only  be  prepared  by  the  agency  of 
cells  whose  duration  is  brief;  for  we  have  no  instance  in  which  the  tissue  con- 
cerned in  its  elaboration  possesses  more  than  a  very  limited  term  of  existence. 
But  by  its  active  vital  operations,  it  produces  a  fluid  adapted  for  the  nutrition 
of  parts  which  are  of  a  much  more  solid  and  permanent  character,  and  which 
undergo  little  change  of  any  kind  subsequently  to  their  complete  development; 
this  want  of  tendency  to  decay  being  the  result  of  the  very  same  peculiarity  of 
constitution  as  that  which  renders  them  unfit  to  participate  in  the  proper  vital 
phenomena  of  the  organism  (§  114).  Thus  the  final  cause  or  purpose  of  all  the 
Nutritive  functions  of  the  Plant,  so  far  as  the  individual  is  concerned,  is  to  pro- 
duce an  indefinite  extension  of  the  dense,  woody,  almost  inert,  and  permanent 
portions  of  the  fabric,  by  the  continued  development,  decay,  and  renewal  of  the 
soft,  active,  and  transitory  cellular  parenchyma. — The  Nutritive  functions,  how- 
ever, also  supply  the  materials  for  the  continuance  of  the  race,  by  the  genera- 
tion of  new  individuals  ;  since  a  new  germ  cannot  be  formed,  any  more  than  the 
parent  structure  can  be  extended,  without  organizable  materials,  prepared  by  the 
assimilating  process,  and  supplied  to  the  parts  where  active  changes  are  going  on. 
369.  On  analyzing  the  operations  which  take  place  in  the  Animal  body,  we 
find  that  a  large  number  of  them  are  of  essentially  the  same  character  with  the 
foregoing,  and  differ  only  in  the  conditions  under  which  they  are  performed;  so 
that  we  may,  in  fact,  readily  separate  the  Organic  functions,  which  are  directly 
concerned  in  the  development  and  maintenance  of  the  fabric,  from  the  Animal 
functions,  which  render  the  individual  conscious  of  external  impressions,  and 
capable  of  executing  spontaneous  movements.  The  relative  development  of  the 
organs  destined  to  these  two  purposes,  differs  considerably  in  the  several  groups 
of  Animals.  The  life  of  a  Zoophyte  is  upon  the  whole  much  more  "vegetative" 
than  "  animal ;"  and  we  perceive  in  it,  not  merely  the  very  feeble  development  of 
those  powers  which  are  peculiar  to  the  Animal  kingdom,  but  also  that  tendency 
to  indefinite  extension  which  is  characteristic  of  the  Plant.  In  the  Insect,  we 
have  the  opposite  extreme;  the  most  active  powers  of  motion,  and  sensations  of 
which  some  (at  least)  are  very  acute,  coexisting  with  a  low  development  of  the 
organs  of  nutrition.  In  Man,  and  the  higher  classes  generally,  we  have  less 

1  See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  ^120,  494,  554,  Am.  Ed. 


DEPENDENCE   OF   THE   VITAL   ACTIONS.  361 

active  powers  of  locomotion,  but  a  much  greater  variety  of  Animal  faculties ; 
and  the  instruments  of  the  Organic  or  nutritive  operations  attain  their  highest 
development,  and  their  greatest  degree  of  mutual  dependence.  We  see  in  the 
fabric  of  all  beings,  in  which  the  Animal  powers  are  much  developed,  an  almost 
entire  want  of  that  tendency  to  indefinite  extension,  which  is  so  characteristic  of 
the  Plant ;  and  when  the  large  amount  of  food  consumed  by  them  is  considered, 
the  question  naturally  arises,  to  what  purpose  this  food  is  applied,  and  what  is 
the  necessity  for  the  continued  activity  of  the  Organic  functions,  when  once  the 
fabric  has  attained  the  limit  of  its  development. 

370.  The  answer  to  this  question  lies  in  the  fact,  that  the  exercise  of  the 
Animal  functions  is  essentially  destructive  of  their  instruments;  every  operation 
of  the  Nervous  and  Muscular  systems  involving,  as  its  necessary  condition,  a 
disintegration  of  a  certain  part  of  their  tissues ;  so  that  the  duration  of  the  ex- 
istence of  those  tissues  varies  inversely  to  the  use  that  is  made  of  them,  being 
less  as  their  functional  activity  is  greater.     Hence,  when  an  Animal  is  very  in- 
active, it  requires  but  little  nutrition  ;  if  in  moderate  activity,  there  is  a  moderate 
demand  for  food  ;  but  if  its  Nervo-muscular  energy  be  frequently  and  powerfully 
aroused,  the  supply  must  be  increased,  in  order  to  maintain  the  vigor  of  the 
system. — We  are  not  to  measure  the  activity  of  the  Nervous  system,  however, 
like  that  of  the  Muscular,  only  by  the  amount  of  movement  to  which  it  gives 
origin.     For  there  is  equal  evidence,  that  the  demand  for  blood  in  the  Brain, 
the  amount  of  nutrition  it  receives,  and  the  degree  of  disintegration  it  under- 
goes, are  proportional  likewise  to  the  energy  of  the  purely  psychical  operations; 
so  that  the  vigorous  exercise  of  the  intellectual  powers,  or  a  long-continued 
state  of  agitation  of  the  feelings,  produces  as  great  a  "  waste"  of  Nervous  matter, 
as  is  occasioned  by  active  bodily  exercise.     From  this  and  other  considerations, 
we  are  almost  irresistibly  led  to  the  belief  that  every  act  of  Mind  is  inseparably 
connected,  in  our  present  state  of  being,  with  material  changes  in  the  Nervous 
System ;  a  doctrine  not  in  the  least  inconsistent  with  the  belief  in  the  separate 
immaterial  existence  of  the  Mind  itself,  nor  with  the  expectation  of  a  future 
state  in  which  the  communion  of  Mind  with  Mind  shall  be  more  direct  and 
unfettered. 

371.  Thus  in  the  Animal  fabric,  among  the  higher  classes  at  least,  the  func- 
tion or  purpose  of  the  organs  of  Vegetative  life  is  not  so  much  the  extension  of 
the  fabric,  for  this  has  certain  definite  limits,  as  the  maintenance  of  its  integrity, 
by  the  reparation  of  the  destructive  effects  of  the  exercise  of  the  purely  Animal 
powers.     By  the  operations  of  Digestion,  Assimilation,  and  Circulation,  the 
nutritive  materials  are  prepared  and  conveyed  to  the  points  where  they  are  re- 
quired ;  the  Circulation  of  Blood  also  serves  to  transmit  oxygen,  which  is  intro- 
duced by  the  Respiratory  process ;  and  it  has  further  for  its  office  to  convey  away 
the  products  of  that  decomposition  of  the  Muscular  and  Nervous  tissues,  which 
results  from  their  functional  activity,  these  products  being  destined  to  be  sepa- 
rated by  the  Respiratory  and  other  Excreting  operations.     In  the  performance 
of  the  Organic  functions  of  Animals,  as  in  those  of  Plants,  there  is  a  continual 
new  production,  decay,  exuviation,  and  renewal,  of  the  cells  by  whose  instru- 
mentality they  are  effected ;  which  altogether  effect  a  change  not  less  complete 
than  that  of  the  leaves  in  Plants.     But  it  takes  place  in  the  penetralia  of  the 
system,  in  such  a  manner  as  to  elude  observation,  except  that  of  the  most  scru- 
tinizing kind ;  and  it  has  been  in  bringing  this  into  view,  that  the  Microscope 
has  rendered  most  essential  service  in  Physiology. 

372.  The  regular  maintenance  of  the  functions  of  Animal  life  is  thus  entirely 
dependent  upon  the  due  performance  of  the  Nutritive  operations;  a  considera- 
tion of  great  importance  in  practice,  since  a  very  large  proportion  of  what  are 
termed  "  functional  disorders"  (of  the  Nervous  system  especially)  are  immedi- 
ately dependent  upon  some  abnormal  condition  of  the  Blood.     But  there  also 


362  GENERAL   VIEW   OF   THE    HUMAN    FUNCTIONS. 

exists  a  connection  of  an  entirely  reverse  kind,  between  the  Organic  and  Animal 
functions;  for  the  conditions  of  Animal  existence  render  the  former  in  great 
degree  dependent  on  the  latter.  In  the  acquisition  of  food,  for  example,  the 
Animal  has  to  make  use  of  its  senses,  its  psychical  faculties,  and  its  power  of 
locomotion,  to  obtain  that  which  the  Plant,  from  the  different  provision  made 
for  its  support,  can  derive  without  any  such  assistance;  moreover,  the  propul- 
sion of  the  food  along  the  alimentary  canal  of  the  former,  requires  a  series  of 
operations  in  which  Muscular  contractility  is  required,  the  Nervous  and  Muscular 
systems  being  together  employed  at  the  two  extremes;  and  thus  we  see  that  the 
change  in  the  conditions  required  for  the  ingestion  of  food  by  Animals,  has 
rendered  necessary  the  introduction  of  additional  elements  into  the  apparatus, 
to  which  nothing  comparable  was  to  be  found  in  plants.  Again  in  the  function 
of  respiration,  as  performed  in  Man  and  the  higher  animals,  the  Nervous  and 
Muscular  systems  are  alike  involved;  for  the  movements  by  which  the  air  in 
the  lungs  is  being  continually  renewed,  are  dependent  upon  the  action  of  both; 
and  those  by  which  the  blood  is  propelled  through  the  respiratory  organs,  are 
chiefly  occasioned  by  the  contractility  of  a  muscular  organ,  the  heart.  Such 
movements,  however,  as  are  thus  immediately  connected  with  the  maintenance 
of  the  Organic  functions,  do  not  depend  upon  the  will,  and  may  even  be  per- 
formed without  our  consciousness;  they  can  scarcely  be  regarded,  therefore,  as 
forming  part  of  our  proper  Animal  life;  and  the  only  essential  difference  which 
they  present,  from  those  which  are  occasionally  performed  by  Plants  (especially 
such  as  exhibit  the  transmission  of  the  effect  of  a  stimulus  to  some  distance — the 
folding  of  the  leaves  of  the  Mimosa,  or  the  closure  of  the  fly-trap  of  the  Dion^ea, 
for  example),  consists  in  the  instrumentality  through  which  they  are  performed 
— this  being  in  Animals  a  peculiar  Nervous  and  Muscular  apparatus,  whilst  in 
Plants  it  is  only  a  modification  of  the  ordinary  structure. 

373.  From  what  has  been  said,  then,  it  appears  that  all  the  functions  of  the 
Animal  body  are  so  completely  bound  up  together,  that  none  can  be  suspended 
without  the  cessation  of  the  rest.  The  properties  of  all  the  tissues  and  organs 
are  dependent  upon  their  regular  Nutrition,  by  a  due  supply  of  perfectly  elabo- 
rated blood;  this  cannot  be  effected,  unless  the  functions  of  Circulation,  Respi- 
ration, and  Excretion  be  performed  with  regularity — the  first  being  necessary 
to  convey  the  supply  of  nutritious  fluid,  and  the  two  latter  to  separate  it  from 
its  impurities.  The  Respiration  cannot  be  maintained  without  the  integrity  of 
a  certain  part^of  the  Nervo-muscular  apparatus ;  and  the  due  action  of  this,  again, 
is  dependent  upon  its  regular  nutrition.  The  materials  necessary  for  the  replace- 
ment of  those  which  are  continually  being  separated  from  the  blood,  can  only  be 
derived  by  the  Absorption  of  ingested  aliment;  and  this  cannot  be  accomplished, 
without  the  preliminary  process  of  Digestion.  The  introduction  of  food  into  the 
stomach,  again,  !s  dependent,  like  the  actions  of  Respiration,  upon  the  operations 
of  the  muscular  apparatus  and  of  a  part  of  the  nervous  centres ;  and  the  previous 
acquirement  of  food  necessarily  involves  the  purely  Animal  powers.  Now  it 
will  serve  to  show  the  distinction  between  these  powers,  and  those  which  are 
merely  subservient  to  Organic  life,  if  we  advert  to  the  case,  which  is  of  no  un- 
frequent  occurrence,  of  a  Human  being,  deprived,  by  some  morbid  condition  of 
the  brain,  of  all  the  powers  of  Animal  life,  sensation,  thought,  volition,  &c. ; 
and  yet  capable  of  maintaining  a  Vegetative  existence,  in  which  all  the  organic 
functions  go  on  as  usual — that  division  of  the  nervous  system  which  is  concerned 
in  the  movements  whereon  some  of  them  depend,  not  being  yet  affected  by  the 
morbid  influence.  It  is  evident  that  we  can  assign  no  definite  limits  to  such  a 
state,  so  long  as  the  respiratory  movements  are  sustained,  and  the  necessary 
food  is  placed  within  reach  of  the  grasp  of  the  muscles  that  will  convey  it  into 
the  stomach :  as  a  matter  of  fact,  however,  it  is  seldom  of  long  continuance, 
since  the  disordered  state  of  the  brain  is  sure  to  extend  itself,  sooner  or  later,  to 


FUNCTIONS   OF  VEGETATIVE   LIFE. 

the  rest  of  the  nervous  system.  This  condition  may  be  experimentally  imitated, 
however,  by  the  removal  of  the  brain,  in  many  of  the  lower  animals,  whose 
bodies  will  sustain  life  for  many  months  after  such  a  mutilation;  but  this  can 
only  take  place,  when  that  food  is  conveyed  by  external  agency  within  the 
pharynx,  which  they  would,  if  in  their  natural  condition,  have  obtained  for  them- 
selves. .  A  similar  experiment  is  sometimes  made  by  Nature  for  the  Physiologist, 
in  the  production  of  foatuses,  as  well  of  the  human  as  of  other  species,  in  which 
the  brain  is  absent;  these  can  breathe  and  suck  and  swallow,  and  perform  all 
their  organic  functions;  and  there  is  no  assignable  limit  to  their  existence,  so 
long  as  they  are  duly  supplied  with  food.1  Hence  we  may  learn  the  exact  nature 
of  the  dependence  of  the  Organic  functions  upon  those  of  purely  Animal  life ; 
and  we  perceive  that,  though  less  immediate  than  it  is  upon  the  simple  excito- 
motor  actions  of  the  nervous  and  muscular  systems,  it  is  not  less  complete.  On 
the  other  hand,  the  functions  of  animal  life  are  even  more  closely  dependent 
upon  the  Nutritive  actions,  than  are  those  of  organic  life  in  general ;  for  many 
tissues  will  retain  their  several  properties  and  their  power  of  growth  and  exten- 
sion, for  a  much  longer  period  after  a  general  interruption  of  the  circulation, 
than  will  the  Nervous  structure;  which  is,  indeed,  instantaneously  affected  by 
a  cessation  of  the  due  supply  of  blood,  or  by  the  depravation  of  its  quality 
(§  536). 

2.  Functions  of  Vegetative  Life. 

374.  As  a  certain  change  of  composition  of  the  Organized  fabric  is  a  necessary 
condition  of  every  manifestation  of  its  Vital  activity,  it  is  obviously  requisite 
that  a  provision  should  exist  for  the  replacement,  by  new  matter,  of  all  those 
particles,  which,  having  lost  their  vital  endowments,  are  in  process  of  return 
to  the  condition  of  inorganic  matter.  And  hence,  of  course,  every  increase  in 
the  activity  of  the  Animal  functions  becomes  a  source  of  augmented  demand  for 
nourishment;  provided,  at  least,  that  such  increase  does  not  go  to  the  extent  of 
exhausting  the  vital  energies,  and  thus  of  preventing  the  due  performance  of 
the  Nutritive  functions.  A  constant  supply  of  Aliment  is  therefore  needed  for 
the  maintenance  of  the  body,  after  it  has  arrived  at  its  full  development.  The 
effects  of  the  process  of  waste  and  decay,  uncompensated  by  that  of  renovation, 
are  seen  in  starvation  and  in  diseases  of  exhaustion  (§  416);  in  which  there  is  a 
gradual  diminution  in  the  bulk  of  nearly  all  the  tissues  of  the  body,  so  that, 
before  death  supervenes,  the  total  reduction  in  weight  is  very  considerable. — 
But  in  the  growing  state  of  the  organism  there  is,  of  course,  an  additional 
demand  for  Aliment,  to  supply  the  materials  for  the  extension  which  is  continu- 
ally taking  place  in  it.  This,  however,  does  not  make  so  great  a  difference  as 
it  might  appear  to  do,  in  the  supply  of  food  which  is  required.  For  if  the  abso- 
lute addition  which  is  made  by  growth  to  the  body  in  any  given  time,  be  com- 
pared with  the  amount  of  change  of  composition  which  takes  place  in  the  same 
period — the  latter  being  judged  of  by  the  quantity  of  food  consumed,  and  by  the 
amount  of  excrementitious  matter  which  passes  off  by  the  lungs,  liver,  kidneys, 
skin,  &c. — it  will  be  found  to  bear  but  a  very  small  proportion  to  it.  The  fact 
is  rather,  that,  during  the  whole  period  of  growth,  there  is  (so  to  speak)  a  con- 
tinual remodelling  of  the  entire  fabric;  the  life  of  each  part  being  brief,  in  order 

1  A  very  remarkable  case  has  been  mentioned  to  the  Author  by  his  friend  Mr.  Wallis  of 
Hull;  the  subject  of  which  has  never,  from  the  time  of  his  birth,  exhibited  any  distinct 
indication  of  consciousness,  and  has  yet,  by  sedulous  care,  been  reared  to  the  age  of  ten 
years.  There  is  no  appearance  of  any  malformation  about  the  Brain,  and  yet  it  must  ob- 
viously be  functionally  inactive ;  for  no  movements  have  ever  been  witnessed,  which  seem 
to  proceed  from  any  higher  centre  than  the  Medulla  Oblongata.  Even  in  the  administra- 
tion of  nourishment,  it  is  necessary  that  the  food  should  be  carried  back  into  the  pharynx, 
so  that  it  may  be  grasped  by  the  reflex  action  of  its  constrictors. 


364  GENERAL   VIEW   OF   THE   HUMAN   FUNCTIONS. 

that  its  renovation  may  be  effected  on  a  somewhat  different  scale  (§§  130,  131). 
And  thus  it  happens  that  children  require  a  much  larger  amount  of  food  in  pro- 
portion to  their  bulk,  than  that  which  suffices  for  adults.  On  the  other  hand, 
in  old  persons,  the  life  of  each  part  is  comparatively  slow;  its  vital  operations 
are  deficient  in  activity;  and  the  processes  of  waste  and  the  demand  for  food  are 
proportionally  retarded  (§  133). 

375.  But  another  and  most  important  source  of  demand  for  food,  in  Man, 
and  warm-blooded  animals  generally,  arises  out  of  the  requirements  of  the  com- 
bustive  process,  whereby  the  Heat  of  the  body  is  maintained.     This  demand 
will  vary,  cseteris  paribus,  with  the  amount  of  heat  to  be  generated,  which  bears 
a  direct  proportion  to  the  depression  of  the  external  temperature,  the  standard 
of  the  body  itself  being  fixed.     Hence  external  Cold  comes  to  be  a  source  of 
demand  for  food;  whilst  artificial  warmth  may  be  made  to  take  the  place  of  the 
nourishment  otherwise  required  for  this  purpose;  as  was  shown  by  the  remark- 
able experiments  of  Chossat,  hereafter  to  be  referred  to  (CHAPS,  vn.  and  xin.). 
But  if  the  amount  of  exercise  taken  be  very  considerable,  especially  in  warm 
climates,  where  the  demand  for  the  production  of  Heat  is  reduced  to  its  minimum, 
a  sufficient  amount  of  pabulum  for  the  respiratory  process  may  be  provided  by 
the  disintegration  of  the  nervo-muscular  apparatus,  without  any  special  supply 
being  required. 

376.  The  demand  for  food  is  increased  by  any  cause  which  creates  an  unusual 
drain  or  waste  in  the  system.     Thus  an  extensive  suppurating  action  can  be 
sustained  only  by  a  large  supply  of  highly  nutritious  food.     The  mother,  who 
has  to  furnish  the  daily  supply  of  milk,  which  constitutes  the  sole  support  of 
her  offspring,  needs  an  unusual  sustenance  for  this  purpose.     And  there  are 
states  of  the  s^tem,  in  which  the  solid  tissues  seem  to  possess  an  abnormal 
tendency  to  decomposition,  and  in  which  an  increased  supply  of  aliment  is  there- 
fore required.     This  is  the  case,  for  example,  in  Diabetes;  one  of  the  first  symp- 
toms of  which  disease  is  the  craving  appetite,  that  seems  as  if  it  would  be  never 
satisfied.     And  there  can  be  no  doubt  that,  putting  aside  all  the  other  circum- 
stances which  have  been  alluded  to,  there  is  much  difference  amongst  individuals, 
in  regard  to  the  rapidity  of  the  changes  which  their  organism  undergoes,  and 
the  amount  of  food  consequently  required  for  its  maintenance. 

377.  The  want  of  solid  aliment  is  made  known  by  the  feeling  of  Hunger; 
and  that  of  liquids,  by  the  feeling  of  Thirst.     These  feelings,  as  will  be  shown 
hereafter  (CHAP.  vn.  SECT.  2),  are  but  secondarily  dependent  upon  the  state 
of  the  stomach;  and  may  be  considered,  in  the  state  of  health,  as  tolerably 
faithful  indications  of  the  wants  of  the  body  at  large.     They  become  the  stim- 
ulants to  mental  operations,  having  for  their  object  the  gratification  of  the  de- 
sire by  the  acquisition  of  food.     In  the  state  of  Infancy,  the  actions  which  they 
prompt  are  obviously  automatic;  that  is,  they  are  performed  in  direct  respond- 
ence  to  the  appropriate  stimulus,  and  do  not  involve  any  idea  of  purpose  or 
object  on  the  part  of  the  being  which  executes  them.     But,  in  all  succeeding 
periods  of  life,  they  are  purely  voluntary ;  being  performed  with  a  designed  or 
purposive  adaptation  of  means,  to  ends  which  are  clearly  before  the  conscious- 
ness.    The  reception  of  food  into  the  mouth,  and  its  preparation  by  the  acts 
of  mastication  and  insalivation,  would  seem  rather  to  belong  to  the  consensual 
or  " sensori-motor"  class  of  movements;  being  performed  quite  independently 
of  the  will,  whenever  that  power  is  in  abeyance,  or  is  differently  directed.     By 
these  movements,  the  aliment  is  brought  within  reach  of  the  pharyngeal  mus- 
cles, whose  contraction  cannot  be  effected  by  the  will,  but  is  purely  reflex,  or 
"  excito-motor,"  resulting  merely  from  the  conveyance  to  the  Medulla  Oblongata 
of  the  impression  made  upon  the  fauces  by  the  contact  of  the  substance  swal- 
lowed, and  from  the  reflexion  of  an  influence  excited  by  that  impression,  back 
to  the  muscles.     By  these  it  is  propelled  down  the  oesophagus;  and,  after  their 


FUNCTIONS    OF   VEGETATIVE   LIFE.  365 

action  has  ceased,  it  is  taken  up  (as  it  were)  by  the  muscular  coat  of  the  oeso- 
phagus itself,  and  is  conveyed  into  the  stomach.  How  far  the  movements  of  the 
lower  parts  of  the  oesophagus  and  of  the  stomach  are  in  Man  dependent  upon 
reflex  action,  is  uncertain;  the  facts  which  have  been  ascertained  on  this  point, 
by  experiment  on  animals,  will  be  detailed  in  their  proper  place  (§§  428,  430). 

378.  In  the   Stomach,  the  food,  certain  components   of  which  have  been 
already  altered  by  the  chemical  action  of  the  saliva,  is  brought  Bunder  the  influ- 
ence of  the  gastric  secretion;  the  chemical  action  of  which,  aicled  by  the  con- 
stantly-elevated temperature  of  the  interior  of  the  body,  and  by  the  continual 
agitation  effected  by  the  contractions  of  the  parietes  of  the  organ,  effects  a 
more  or  less  complete  reduction  of  it.     Some  of  its  nutritive  components,  being 
actually  dissolved  by  the  gastric  juice,  are  thus  prepared  for  immediate  absorp- 
tion; but  others  require  the  admixture  of  the  biliary  and  pancreatic  secretions, 
whereby  various  changes  are  effected  in  their  condition,  which  prepare  them 
also  for  reception  into  the  circulating  system.     The  nutritious  portion  being 
gradually  taken  up  by  the  Bloodvessels  and  by  the  Absorbent  vessels  (or  Lac- 
teals),  which  are  distributed  on  the  walls  of  the  alimentary  canal,  the  indigesti- 
ble residue  is  propelled  along  the  intestinal  tube  by  the  simple  contractility  of 
its  walls,  undergoing  at  the  same  time  some  further  change,  by  which  the  nu- 
tritive materials  are  still  more  completely  extracted  from  it.     And  at  last,  the 
excrementitious  matter,  consisting  not  only  of  the  insoluble  portion  of  the  food 
taken  into  the  stomach,  but  also  of  part  of  the  secretion  of  the  liver,  and  of  that 
of  the  mucous  surface  of  the  intestines  and  of  their  glandulge,  is  voided  from 
the  opposite  extremity  of  the  canal,  by  a  muscular  exertion,  which  is  partly 
reflex,  like  that  of  deglutition,  but  is  partly  voluntary,  especially  (as  it  would 
appear)  in  Man.     The  whole  of  this  series  of  operations,  by  which  the  nutri- 
tive materials  are  prepared  for  being  absorbed,  may  be  considered  as  constituting 
the  function  of  Digestion. 

379.  The  introduction  of  the  nutritive  materials  thus  prepared,  into  the  ves- 
sels which  convey  them  to  the  tissues,  constitutes  the  function  of  Absorption. 
But  these  materials  undergo  important  changes  in  their  progress  towards  the 
centre  of  the  circulation,  whereby  they  are  brought  more  nearly  to  the  condition 
of  true  Blood;  and  these  changes  are  designated  by  the  term  Assimilation. — 
There  seems  no  doubt  that  fluid  containing  saline,  albuminous,  or  other  matters 
in  a  state  of  complete  solution,  may  be  absorbed  by  the  Bloodvessels  with  which 
the  mucous  membrane  of  the  alimentary  canal  is  so  copiously  supplied ;  and  this 
simple  process  of  imbibition  probably  takes  place  according  to  the  physical  laws 
of  Endosmose.     But  the  selection  and  absorption  of  some  of  the  nutritive  mate- 
rials appear  to  be  performed,  not  by  vessels,  but  by  the  specific  vital  endowments 
of  cells  (§  460),  which  subsequently  yield  up  their  contents  to  the  Lacteals. 
The  fluid  thus  absorbed,  which  now  receives  the  name  of  Chyle,  is  propelled 
through  the  Lacteals  by  the  contractility  of  their  walls ;  aided  in  part,  perhaps, 
by  a  vis  a  tergo  derived  from  the  force  of  the  absorption  itself. — With  the  recep- 
tion of  the  nutritious  fluid  into  the  vessels,  commences  its  real  preparation  for 
Organization.     Up  to  that  period,  it  cannot  be  said  to  be  in  any  degree  vital- 
ized; the  changes  which  it  has  undergone  being  only  of  a  chemical  and  physical 
nature,  and  such  as  merely  prepare  it  for  subsequent  assimilation.     But  in  the 
passage  of  that  which  has  been  taken  up  by  the  Bloodvessels,  through  the 
Liver,  very  important  changes  are  effected  in  its  condition,  whereby  it  is  brought 
to  a  state  more  nearly  corresponding  with  true  Blood.     And  in  like  manner,  the 
Chyle,  in  passing  through  the  long  and  tortuous  system  of  Absorbent  vessels 
and  glands,  undergoes  changes  which,  with  little  chemical  difference,  manifest 
themselves  by  a  decided  alteration  in  its  properties ;  so  that  the  chyle  of  the 
Thoracic  duct  is  evidently  a  very  different  fluid  from  the  chyle  of  the  Lacteals, 
approaching  much  nearer  to  blood  in  its  general  characters.     These  characters 


366  GENERAL   VIEW   OF   THE    HUMAN   FUNCTIONS. 

are  such  as  indicate  that  the  process  of  organization  and  vitalization  has  com- 
menced;  as  may  be  known  alike  from  the  microscopic  appearance  of  the  fluid, 
and  from  the  actions  it  performs  when  removed  from  the  body.  The  Chyle 
thus  modified  is  conveyed  into  the  Sanguiferous  system  of  vessels,  and  flows  di- 
rectly to  the  heart;  by  which  it  is  transmitted,  with  the  mass  of  the  blood,  to 
the  lungs.  It  there  has  the  opportunity  of  excreting  its  superfluous  carbonic 
acid,  and  of  absorbing  oxygen;  and  probably  acquires  gradually  the  properties 
by  which  the  blood  previously  formed  is  distinguished,  thus  becoming  the  pabu- 
lum vitde  for  the  whole  system. — The  fluid  which  is  brought  by  the  Lymphatic 
system,  from  those  parts  of  the  organism  to  which  it  is  distributed,  is  obviously 
of  a  character  no  less  nutritive  than  the  chyle,  though  formerly  regarded  as  ex- 
crementitious;  its  source  appears  to  be  partly  in  the  serous  transudation  which 
escapes  from  the  bloodvessels  into  the  substance  of  the  tissues,  the  superfluity 
of  which  is  taken  up  again  and  carried  back  into  the  circulation  by  the  lympha- 
tics; and  partly,  it  may  be,  in  the  re-solution  of  such  portions  of  the  tissues 
themselves,  as,  though  dead,  are  not  in  a  state  of  decomposition  that  prevents 
their  components  from  being  again  made  available  as  nutritive  materials.  The 
Lymph,  like  the  chyle,  seems  to  undergo  an  elaborating  process  in  its  passage 
towards  the  thoracic  duct,  whereby  it  is  gradually  assimilated  to  blood  in  its 
nature. 

380.  The  Circulation  of  the  Blood  through  the  tissues  and  organs  which  it  is 
destined  to  support,  is  a  process  evidently  necessary,  alike  for  supplying  them 
with  the  nutritious  materials  which  are  provided  for  the  repair  of  their  waste, 
and  for  removing  those  elements  of  their  fabric  which  are  in  a  state  of  incipient 
decomposition.     In  the  lowest  classes  of  organized  beings,  every  portion  of  the 
structure  is  in  direct  relation  with  its  nutritive  materials;  it  can  absorb  for  itself 
that  which  is  required;  and  it  can  readily  part  with  that  of  which  it  is  desirable 
to  get  rid.     Hence,  in  such,  no  general  circulation  is  necessary.     In  Man,  on 
the  other  hand,  the  digestive  cavity  occupies  so  small  a  portion  of  the  body,  that 
the  organs  at  a  distance  from  it  have  no  other  means  than  their  vascular  com- 
munication affords,  of  participating  in  the  results  of  its  operations;  and  it  is, 
moreover,  necessary,  that  they  should  be  continually  furnished  with  the  organi- 
zable  materials,  of  which  the  occasional  operation  of  the  digestive  process  would 
otherwise  afford  only  an  intermitting  supply.     This  is  especially  the  case,  as 
already  mentioned,  with  the  Nervous  system,  which  is  so  predominant  a  feature 
in  the  constitution  of  Man;  and  we  accordingly  find  both  objects  provided  for, 
in  the  formation  of  a  large  quantity  of  a  semi-organized  product,  which  contains 
within  itself  the  materials  of  all  the  tissues,  and  is  constantly  being  carried  into 
relation  with  them. — The  propulsion  of  the  Blood  through  the  large  trunks, 
which  subsequently  divide  into  capillary  vessels,  is  due  to  the  contractions  of  a 
hollow  muscular  organ,  the  Heart;  but  these,  like  the  peristaltic  movements  of 
the  alimentary  canal,  are  quite  independent  of  the  agency  of  the  Nervous  system ; 
and  are  therefore  to  be  referred  to  the  class  of  Organic  movements,  such  as  occur 
in  Vegetables.     The  rate  and  force  of  the  Heart's  movements  are  greatly  influ- 
enced, however,  by  conditions  of  the  Nervous  system ;  and  these  also,  by  calling 
into  play  the  contractility  of  the  walls  of  the  Arteries,  exert  a  powerful  influence 
upon  their  caliber,  and  consequently  upon  the  distribution  of  blood  to  particular 
parts  and  organs,  as  we  see  in  the  acts  of  blushing  and  erection. 

381.  Upon  the  circulation  of  the  blood  through  all  parts  of  the  fabric,  depends 
in  the- first  place  the  Nutrition  of  the  tissues.   Upon  this  subject,  formerly  involved 
in  the  greatest  obscurity,  much  light  has  recently  been  thrown  by  Microscopic 
discovery;  it  being  now  understood  (as  explained  in  the  preceding  Chapter),  that 
the  continued  growth  and  renewal  of  each  tissue  is  effected  by  a  continuation  of 
a  process  essentially  similar  to  that  by  which  it  was  first  developed.   The  greatest 
difficulty,  in  the  present  condition  of  our  knowledge,  is  to  comprehend  the  rea- 


FUNCTIONS   OF   VEGETATIVE   LIFE.  367 

son  why  such  a  variety  of  products  should  spring  up  in  the  first  instance  ;  when 
the  cells  in  which  they  all  originate  appear  to  be  so  exactly  alike.  The  im- 
portant discoveries  now  referred  to  are  not  confined  to  healthy  structures;  for 
it  has  been  ascertained  that  diseased  growths  have  a  similar  origin  and  mode  of 
extension,  and  that  the  malignant  character  assigned  to  Cancer,  Fungus  Hae- 
matodes,  and  other  such  productions,  is  partly  connected  with  the  fact  that 
they  are  composed  of  cells  which  undergo  little  metamorphosis,  and  retain  their 
reproductive  power;  so  that  from  a  single  cell,  as  from  that  of  a  Vegetable  Fun- 
gus, a  large  structure  may  rapidly  spring  up,  the  removal  of  which  is  by  no 
means  attended  with  any  certainty  that  it  will  not  speedily  reappear,  from  some 
germs  left  in  the  system. — The  independent  vitality  of  the  cells  in  which  all 
organized  tissues  originate,  might  be  of  itself  a  satisfactory  proof  that,  in  Ani- 
mals, as  in  Plants,  the  actions  of  Nutrition  are  effected  by  the  powers  with 
which  they  are  individually  endowed;  and  that,  whatever  influence  the  Nervous 
system  may  have  upon  them,  its  agency  is  not  essential  to  their  performance. 
Moreover,  it  is  certain  that  no  formation  of  nervous  matter  takes  place  in  the 
embryonic  structure,  until  the  processes  of  Organic  life  have  been  for  some  time 
in  active  operation.  The  influence  which  the  Nervous  System  is  known  to  have 
upon  the  function  of  Nutrition,  is  probably  exerted  in  two  ways;  first,  through 
its  power  of  regulating  the  diameter  of  the  arteries  and  capillaries,  by  which  it 
controls  in  some  degree  the  afflux  of  blood;  and  secondly,  through  the  more 
direct  relation  of  the  Nervous  force  to  those  other  forms  of  Vital  agency,  which 
manifest  themselves  in  the  growth,  development,  and  maintenance  of  the  living 
tissues  (§  352). 

382.  The  continual  disintegration  to  which  the  living  tissues  are  subject,  from 
the  various  causes  already  referred  to,  renders  it  necessary  that  a  means  should 
be  provided  for  conveying  away  the  waste,  as  well  as  for  supplying  the  new  ma- 
terial. This  is  partly  effected  by  the  Venous  circulation ;  which  takes  up  a 
large  part  of  the  products  of  incipient  decomposition,  and  conveys  them  to  or- 
gans of  Excretion,  by  which  they  may  be  separated  and  cast  forth  from  the  body. 
The  first  product  of  the  decay  of  all  organized  structures  is  carbonic  acid;  and 
this  is  the  one,  which  is  most  constantly  and  rapidly  accumulating  in  the  sys- 
tem, and  the  retention  of  which,  therefore,  within  the  body,  is  the  most  injuri- 
ous. Accordingly,  we  find  a  most  important  organ — the  Pulmonary  apparatus 
— adapted  to  remove  it;  and  to  this  the  whole  current  of  Venous  blood  passes, 
before  it  is  again  sent  through  the  system.  The  efficient  performance  of  this 
function  of  Respiration  is  so  essential  to  the  well-being  of  warm-blooded  animals, 
that  a  special  heart  is  provided  for  propelling  the  blood  through  their  lungs,  in 
addition  to  the  one  possessed  by  most  of  the  lower  animals,  the  function  of 
which  is  the  propulsion  of  the  blood  through  the  system.  In  these  organs,  the 
blood  is  subjected  to  the  influence  of  the  atmosphere,  whereby  the  carbonic  acid 
with  which  it  was  charged  is  removed,  and  replaced  by  oxygen;  and  this  change 
takes  place  through  the  delicate  membrane  that  lines  the  air-cells  of  the  lungs, 
in  accordance  with  the  physical  law  of  the  mutual  diffusion  of  gases.  The  in- 
troduction of  oxygen  into  the  blood  is  necessary  for  the  maintenance  of  those 
peculiar  vivifying  powers,  by  which  the  Nervous  and  Muscular  systems  are  kept 
in  a  state  fit  for  activity ;  and  its  union  with  their  elements  appears  to  be  a  neces- 
sary condition  of  the  manifestation  of  their  peculiar  powers.  Of  this  union, 
carbonic  acid  is  one  of  the  chief  products ;  and  we  shall  find  that  the  demand  for 
oxygen,  and  the  excretion  of  carbonic  acid,  vary  according  to  the  amount  of 
nervo-muscular  action  put  forth.  The  continual  formation  of  carbonic  acid,  in 
this  and  other  interstitial  changes,  has  a  most  important  purpose  in  the  vital 
economy,  that  of  keeping  up  its  temperature  to  a  fixed  standard;  for  the  union 
of  carbon  and  oxygen  in  this  situation  may  be  compared  to  a  process  of  slow 
combustion,  and,  in  combination  with  other  combustive  processes  (in  which  hy- 


368  GENERAL   VIEW   OF   THE    HUMAN   FUNCTIONS. 

drogen,  sulphur,  phosphorus,  &c.,  undergo  oxidation),  it  is  the  principal  means 
of  sustaining  the  independent  heat  of  the  "  warm-blooded"  animal.  There  is  in 
the  system  a  certain  self-adjusting  power,  whereby  the  consumption  of  the 
pabulum  provided  for  the  combustive  process  is  regulated  according  to  the 
external  temperature;  so  that  whilst,  the  external  temperature  being  the 
same,  the  amount  of  carbonic  acid  excreted  varies  with  the  degree  of  mus- 
cular exertion  made  by  the  individual,  any  depression  of  the  external  tempe- 
rature, requiring  an  augmented  production  of  heat,  occasions  an  increased 
combustion  of  the  oxidizable  solids  of  the  body,  which  is  indicated  by  an 
increase  in  the  exhalation  of  carbonic  acid  from  the  lungs. — The  interchange 
of  oxygen  and  carbonic  acid  between  the  atmosphere  and  the  blood,  can  only  be 
kept  up  by  a  continual  renewal  of  the  air  in  the  interior  of  the  lungs,  and  of  the 
blood  in  their  capillaries.  The  former  is  effected  by  a  set  of  muscular  move- 
ments that  depend  on  the  "reflex"  power  of  certain  nervous  centres,  and  not  on 
any  exertion  of  the  will  of  the  individual.  It  is  not  even  requisite  that  he 
should  be  conscious  of  their  performance ;  the  ordinary  power  of  the  stimulus 
that  excites  the  movement  not  being  sufficient  to  cause  itself  to  be  felt,  unless 
attention  be  specially  directed  to  it.  But  if  the  respiratory  movements  be  sus- 
pended for  a  short  time,  sensations  of  distress  are  soon  experienced,  which 
rapidly  augment  with  the  continuance  of  the  suspension;  and  no  exertion  of  the 
will  can  any  longer  prevent  the  performance  of  the  movements  which  are  appro- 
priate to  relieve  them.  Thus  we  see  that  these  movements,  although  placed  in 
Man  under  the  control  of  the  Will  to  such  an  extent  as  to  enable  him  to  regu- 
late them  in  the  actions  of  speech,  are  in  themselves  quite  as  independent  of  that 
will,  as  are  those  of  the  Heart,  whose  automatic  power  has  been  already  alluded  to. 

383.  The  function  of  the  Liver  as  an  excreting  organ  is,  like  that  of  the  lungs, 
twofold:  it  separates  from  the  blood  a  large  quantity  of  the  superfluous  hydro- 
carbon, which  it  acquires  in  circulating  through  the  tissues ;   and  it  combines 
this  with  other  elements  (§§  67-71),  into  a  secretion,  which  is  of  great  impor- 
tance in  the  digestive  process.     The  hepatic  circulation,  however,  is  not  kept  up 
by  a  distinct  impelling  organ;  but  the  venous  blood  from  the  abdominal  viscera 
(and,  in  the  lower  Vertebrata,  that  from  the  posterior  part  of  the  body)  passes 
through  the  Liver  on  its  return  to  the  heart. — But  further,  all  animal  sub- 
stances have  a  tendency,  during  their  decomposition,  to  throw  off  nitrogen,  as 
well  as  carbon;   and  this  nitrogen,  in  combination  with  other  elements,  forms 
those  peculiar  azotized  compounds  (§§  51-63),  which  it  is  the  special  function 
of  the  Kidney  to  eliminate  from  the  circulating  fluid.     The  most  characteristic 
of  these  in  Man,  namely  urea,  contains  a  larger  proportion  of  nitrogen  than  is 
found  in  any  other  organic  compound;  and  is  identical  in  its  chemical  nature 
with  cyanate  of  ammonia.     Its  production  seems  in  great  part  to  depend  upon 
the  disintegration  of  the  muscular  tissue ;  but  there  is  also  evidence  that  it  may 
result  from  the  retrograde  metamorphosis  of  albuminous  or  even  of  gelatinous 
matters  circulating  in  the  blood.     The  action  of  the  kidneys  is  equally  essential 
to  the  continued  performance  of  the  other  vital  functions,  with  that  of  the  lungs 
and  liver;  since  death  invariably  follows  its  suspension,  unless  some  other  means 
be  provided  by  Nature  (as  occasionally  happens),  for  the  separation  of  its  cha- 
racteristic excretion  from  the  circulating  blood. 

384.  The  various  Secretions  which  have  not  already  been  adverted  to,  appear 
for  the  most  part  to  have  for  their  object  the  performance  of  some  special  func- 
tion in  the  system,  rather  than  the  conveyance  out  of  it  of  any  substances  which 
it  would  be  injurious  to  retain.     This  is  the  case,  for  example,  in  regard  to  the 
secretion  of  the  Lachrymal,  Salivary,  and  Mammary  Glands,  as  well  as  with 
that  of  the  Mucous  and  Serous  Membranes.     The  Excretion  of  fluid  from  the 
cutaneous  surface,  however,  appears  to  answer  two  important  purposes — the 
removal  from  the  body  of  a  portion  of  its  superfluous  fluid,  containing  products 


FUNCTIONS   OF   VEGETATIVE  LIFE.  369 

of  decomposition — and  the  regulation  of  its  temperature.  Just  as,  by  the  ac- 
tion of  the  Lungs,  the  conditions  are  supplied,  by  which  the  temperature  of  the 
body  is  kept  up  to  a  certain  standard,  so,  by  that  of  the  Skin,  it  is  prevented 
from  rising  too  high;  for  by  the  continual  excretion  from  its  surface,  of  fluid 
which  has  to  be  carried  off  by  evaporation,  a  degree  of  cold  is  generated,  which 
keeps  the  calorific  processes  in  check ;  and  this  excretion  is  augmented,  in  pro- 
portion to  the  elevation  of  the  external  temperature,  which  seems,  in  fact,  the 
direct  stimulus  to  the  process. — In  all  forms  of  true  Secretion,  the  selection  of 
the  materials  to  be  separated  from  the  blood,  is  accomplished,  like  selective 
Absorption,  by  the  agency  of  cells.  These  are  developed  in  the  interior  of  the 
secreting  organ;  and  when  they  are  distended  with  the  fluid  they  have  imbibed, 
their  term  of  life  appears  to  have  expired,  so  that  they  burst  or  liquefy,  yielding 
their  contents  to  the  ducts,  by  which  the  secreted  product  is  conveyed  away. 
In  the  case  of  Adipose  tissue,  we  have  an  instance  in  which  the  secreted  pro- 
duct (separated  from  the  blood  by  the  cells  of  which  this  tissue  essentially  con- 
sists) is  not  carried  out  of  the  body,  but  remains  to  form  a  constituent  part  of 
it. — The  regulation  of  the  amount  of  fluid  in  the  vessels,  is  provided  in  a  kind 
of  safety-valve  structure,  existing  in  the  Kidneys,  which  readily  permits  the 
escape  of  aqueous  fluid  from  the  capillary  vessels,  into  the  urinary  canals,  by  a 
process  of  physical  transudation,  which  is  altogether  distinct  from  the  secretion 
of  the  solid  matter,  which  it  is  the  office  of  the  kidneys  to  separate  from  the 
circulating  blood.  Hence,  if  the  excretion  of  fluid  from  the  skin  be  checked  by 
cold,  so  that  an  accumulation  would  take  place  in  the  vessels,  the  increased 
pressure  within  them  causes  an  increased  escape  of  water  through  the  kidneys. 

385.  There  is  no  sufficient  reason  to  believe,  that  the  Nervous  System  has 
any  more  direct  influence  on  the  process  of  Secretion,  than  it  has  been  stated  to 
have  on  that  of  Nutrition.     That  each  glandular  organ  has  an  independent  ac- 
tion of  its  own,  in  virtue  of  the  endowments  of  its  component  cells,  can  scarcely 
now  be  doubted.     Still,  daily  experience  teaches  that  almost  every  secretion  in 
the  body  is  affected  by  states  of  mind,  which  must  operate  through  the  nerves ; 
and  this  may  be  fairly  accounted  for  in  part  by  the  remarkable  influence  which 
the  Nervous  system  possesses  over  the  Circulation,  but  must  also  be  in  part 
attributed  to  the  special  agency  of  the  Nervous  force  upon  the  chemical  or  vital 
process  of  Secretion  itself.     The  flow  of  the  secreted  fluids  through  their  efferent 
ducts,  seems  to  be  principally  caused  by  the  proper  contractility  of  these,  which 
(like  that  of  the  heart  and  alimentary  canal)  is  directly  stimulated  by  the  con- 
tact of  their  contents ;  but  there  is  also  evidence  that  this  contractility  may  be 
affected  (as  it  is  in  those  two  instances)  by  the  nervous  system.     Where,  as 
happens  in  the  case  of  the  urinary  excretion,  there  is  a  reservoir  into  which  it 
is  received  as  feist  as  it  is  formed,  for  the  purpose  of  preventing  the  inconve- 
nience which  its  constant  passage  from  the  body  would  otherwise  occasion,  the 
power  of  emptying  this  reservoir  is  usually  placed  in  some  degree  under  the 
dominion  of  the  will,  although  chiefly  governed  by  reflex  action.     It  is  obvious 
that  such  a  provision  is  by  no  means  essential  to  the  function;  and  that  it  has 
for  its  object  the  adaptation,  merely,  of  that  function,  to  the  conditions  of  Ani- 
mal existence. 

386.  Thus  we  see  that  when  we  enter,  as  it  were,  into  the  penetralia  of  the 
Animal  system,  and  study  those  processes  in  which  the  development  and  main- 
tenance of  the  material  fabric  essentially  consist,  we  find  them  performed  under 
conditions  essentially  the  same  as  those  which  obtain  in  Plants;  and  we  observe 
that  the  operations  of  the  Nervous  System  have  none  but  an  indirect  influence 
or  control  over  them.     It  is,  therefore,  quite  philosophical  to  distinguish  these 
Organic  Functions,  or  phenomena  of  Vegetative  Life,  from  those  concerned  in 
the  Life  of  Relation,  or  Animal  Life.    The  distinction  is  indeed  of  great  practical 
importance,  and  lies  at  the  foundation  of  all  Physiological  Science;  yet  it  is  sel- 

24 


370  GENERAL   VIEW   OF   THE    HUMAN    FUNCTIONS. 

dom  accurately  made,  and  a  very  confused  notion  on  the  subject  is  generally 
prevalent.1 

387.  The  process  of  Reproduction,  like  that  of  Nutrition,  has  been  until  re- 
cently involved  in  great  obscurity;  and  although  it  cannot  be  said  to  be  yet 
fully  elucidated,  it  has  been  brought,  by  late  investigations,  far  more  within  our 
comprehension  than  WAS  formerly  deemed  possible.     The  close  connection  be- 
tween the  Reproductive  and  Nutritive  operations,  both  as  regards  their  respec- 
tive characters,  and  their  dependence  upon  one  another,  has  long  been  recog- 
nized j  and  it  is-now  rendered  still  more  evident.     Nutrition  has  not  been  unaptly 
designated  "a  perpetual  reproduction;"  and  the  expression  is  strictly  correct. 
In  the  fully-formed  organism,  the  supply  of  alimentary  material  to  every  part 
of  the  fabric  enables  it  to  produce  a  tissue  resembling  itself;  thus  we  ordinarily 
find  true  bone  produced  only  in  continuity  with  bone,  nerve  with  nerve,  muscle 
with  muscle,  and  so  on.     Hence  it  would  appear  that,  when  a  portion  of  tissue 
has  once  taken  on  a  particular  kind  of  action,  it  continues  to  reproduce  itself  on 
the  same  plan.     But  in  the  developmental  process  it  is  different.     A  single  cell 
is  generated  by  certain  preliminary  actions,  from  which  cell,  all  those  which 
subsequently  compose  the  embryonic  structures,  take  their  origin;  and  it  is  not 
until  a  later  period,  that  any  distinction  of  parts  can  be  traced,  in  the  mass  of 
vesicles  which  spring  from  it.     This  distinction  becomes  more  and  more  obvious 
as  development  advances;  the  form  and  position  of  the  principal  organs  being 
first  marked  out  by  peculiar  aggregations  of  cells;  and  the  intimate  structure  of 
each  being  gradually  brought  to  the  type  which  is  characteristic  of  it. — Hence 
we  may  state  the  essential  character  of  the  function  of  Reproduction  to  consist 
in  the  production  of  a  cell  of  most  peculiar  endowments;  which,  when  supplied 
with  nutriment,  and  acted  on  by  warmth,  does  not  simply  multiply  itself  so  as 
to  produce  a  mere  aggregation  of  similar  cells,  but  gives  origin  to  a  succession 
of  broods,  which  undergo  such  heterogeneous  transformations,  as  ultimately  to 
evolve  an  organism  capable  of  maintaining  an  independent  existence,  in  which 
the  number  of  different  parts  is  equal  to  that  of  the  functions  to  be  performed, 
each  separate  part  having  an  office  distinct  from  that  of  the  rest,  and  being 
specially  adapted  to  it  alone. 

388.  But,  it  will  be  inquired,  how  and  where  in  the  Human  body  (and  in  the 
higher  Animals  in  general)  is  this  embryonic  vesicle  produced,  and  what  are 
the  relative  offices  of  the  two  sexes  in  its  formation?     This  is  a  question  which 
must  still  be  answered  with  some  degree  of  doubt;  and  yet  observed  phenomena, 
if  explained  by  the  aid  of  analogy,  seem  to  lead  to  a  very  direct  conclusion. 
The  embryonic  vesicle  itself,  like  other  cells,  must  arise  from  a  germ;  and 
reasons  will  be  hereafter  given  for  the  belief,  that  this  germ  is  the  product  of 
the  admixture  of  the  contents  of  the  "  sperm-cell"  of  the  male  with  that  of  the 
"germ-cell"  of  the  female;  and  that  this  admixture  is  requisite  for  the  regenera- 
tion of  that  "  germinal  capacity"  which  is  gradually  expended  in  the  develop- 
mental process.     The  operations  immediately  concerned  in  this  function,  as  in 
that  of  Nutrition — namely,  the  preparation  of  the  "  sperm-cells"  and  the  "  germ- 
cells,"  the  act  of  fecundation,  and  the  development  of  the  ovum — are  not  depend- 
ent upon  nervous  agency,  and  are  but  little  influenced  by  it ;  and  the  functions 
of  Animal  Life  are  called  into  play  only  in  the  preliminary  and  concluding  steps 
of  the  process.     In  many  of  the  lower  Animals,  there  is  no  sexual  congress, 
even  where  the  concurrent  action  of  two  sets  of  organs,  belonging  to  two  sepa- 

1  It  has  been  commonly  said,  for  example,  that  the  function  of  Respiration  is  the  con- 
necting link  between  the  two :  the  fact  being,  however,  that  the  true  process  of  Respira- 
tion is  no  more  a  function  of  Animal  life  than  is  any  ordinary  process  of  secretion;  but 
that,  in  order  to  secure  the  constant  interchange  of  air,  which  is  necessary  to  its  perform- 
ance, the  assistance  of  the  nervous  and  muscular  systems  is  called  in,  though  not  in  a  man- 
ner which  necessarily  involve.-;  either  consciousness  or  will. 


FUNCTIONS   OF   ANIMAL   LIFE.  371 

rate  individuals,  is  necessary  for  the  process;  for  the  ova  are  liberated  by  one, 
and  the  spermatozoa  by  the  other,  and  the  accidental  meeting  of  the  two  pro- 
duces the  required  result.  In  many  Animals  higher  in  the  scale,  the  impulse 
which  brings  the  sexes  together  is  of  a  purely  instinctive  kind.  But  in  Man, 
it  is  of  a  very  compound  nature.  The  instinctive  propensity,  unless  unduly 
strong,  is  controlled  and  guided  by  the  will,  and  serves  (like  the  feelings  of 
hunger  and  thirst)  as  a  stimulus  to  the  reasoning  processes,  by  which  the  means 
of  gratifying  it  are  obtained;  and  a  moral  sentiment  or  affection  of  a  much 
higher  kind  is  closely  connected  with  it,  which  acts  as  an  additional  incitement. 
Those  movements,  however,  which  are  most  closely  connected  with  the  essential 
part  of  the  process,  are,  like  those  of  deglutition,  respiration,  &c.,  simply  reflex 
and  involuntary  in  their  character;  and  thus  we  have  another  proof  of  the  con- 
stancy of  the  principle,  that,  where  the  action  of  the  apparatus  of  Animal  Life 
is  brought  into  near  connection  with  the  Organic  functions,  it  is  not  such  as 
requires  the  operation  of  the  purely  animal  powers,  sensation  and  volition. 
Thus,  then,  as  it  has  been  lucidly  remarked,  "  the  Nervous  System  lives  and 
grows  within  an  Animal,  as  a  parasitic  Plant  does  in  a  Vegetable;  with  its  life 
and  growth,  certain  sensations  and  mental  acts,  varying  in  the  different  classes 
of  Animals,  are  connected  by  nature  in  a  manner  altogether  inscrutable  to  man; 
but  the  objects  of  the  existence  of  Animals  require,  that  these  mental  acts 
should  exert  a  powerful  controlling  influence  over  all  the  textures  and  organs  of 
which  they  are  composed." 

3.  Functions  of  Animal  Life. 

389.  The  existence  of  consciousness,  by  which  the  individual  (le  moi,  in  the 
language  of  French  physiologists)  becomes  sensible  of  impressions  made  upon 
its  bodily  structure,  and  the  power  of  spontaneously  exciting  contractions  in  its 
tissues,  by  which  evident  motions  are  produced,  are  to  be  regarded  as  the  cha- 
racteristic attributes  of  the  beings  composing  the  Animal  kingdom;  although 
their  possession  by  many  of  the  tribes  which  seem  to  have  their  most  appropri- 
ate place  in  that  kingdom,  is,  to  say  the  least,  extremely  doubtful.1  Of  the 
movements  exhibited  by  Animals,  there  are  many  which  are  no  more  to  be  re- 
garded as  indications  of  consciousness,  than  are  those  executed  by  certain  plants; 
being  simply  the  expressions  or  manifestations  of  a  peculiar  kind  of  vital  force 
in  the  tissues  by  whose  instrumentality  they  are  performed.  Such  movements, 
in  the  lowest  tribes,  probably  bear  a  much  greater  proportion  to  the  whole 
amount  of  those  exhibited  by  the  beings,  than  they  do  in  the  higher;  whilst 
those  which  we  may  regard  as  specially  dependent  on  a  nervous  system,  appear 
to  constitute  but  a  small  part  of  their  general  vital  actions.  The  life  of  such 
beings,  therefore,  bears  a  much  closer  resemblance  to  that  of  the  Vegetable, 
than  to  that  of  the  higher  Animal.  Their  organic  functions  are  performed  with 
scarcely  more  of  sensible  movement,  than  is  seen  in  plants;  and  of  the  motions 
which  they  do  exhibit  (nearly  all  of  them  immediately  concerned  in  the  main- 
tenance of  the  organic  functions),  it  is  probable  that  many  are  the  result  of  the 
simple  contractility  of  their  tissues,  called  into  action  by  the  stimuli  directly 
applied  to  them.  It  is  scarcely  possible  to  imagine  that  such  beings  can  enjoy 
any  of  those  higher  mental  powers,  which  Man  recognizes  by  observation  on 
himself,  and  of  which  he  discerns  the  manifestations  in  those  tribes,  which, 
from  their  nearer  relation  to  himself,  he  regards  as  more  elevated  in  the  scale 
of  existence.  If  we  direct  our  attention,  on  the  other  hand,  to  the  psychical3 

1  See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  CHAP,  v.,  Am.  Ed. 

2  Here  and  elsewhere  this  term  will  be  employed  in  its  most  extended  sense,  to  desig- 
nate all  the  mental  operations,  whether  intellectual,  emotional,  or  instinctive,  of  which 
Man's  nervous  system  is  the  instrument. 


372  GENERAL  VIEW   OF   THE    HUMAN   FUNCTIONS. 

operations  of  Man,  as  forming  part  of  his  general  vital  actions,  we  perceive  that 
the  proportion  is  completely  reversed.  So  far  from  his  Organic  life  exhibiting 
a  predominance,  it  appears  entirely  subordinate  to  his  Animal  functions,  and 
seems  destined  only  to  afford  the  conditions  for  their  performance.  If  we  could 
imagine  his  nervo-muscular  apparatus  to  be  isolated  from  the  remainder  of  his 
corporeal  structure,  and  to  be  endowed  in  itself  with  the  power  of  maintaining 
its  integrity,  we  should  have  all  that  is  essential  to  our  idea  of  Man.  But,  as 
at  present  constituted,  this  apparatus  is  dependent,  for  the  conditions  of  its 
functional  activity,  upon  the  nutritive  apparatus;  and  the  whole  object  of  the 
latter  appears  to  be  the  supply  of  those  conditions.  That  his  mental  activity 
should  be  thus  made  dependent  upon  the  due  supply  of  his  bodily  wants,  is  a 
part  of  the  general  scheme  of  his  probationary  existence;  and  the  first  excite- 
ment of  his  intellectual  powers  is  in  a  great  degree  dependent  upon  this  arrange- 
ment. 

390.  The  ministration  of  the  Nervous  System  to  purely  Animal  life,  obviously 
consists  in  its  rendering  the  mind  cognizant  of  that  which  is  taking  place  around, 
and  in  enabling  it  to  act  upon  the  material  world,  by  the  instruments  with  which 
the  body  is  provided  for  the  purpose.     It  is  important  to  observe,  that  every 
method  at  present  certainly  known,  by  which  Mind  can  communicate  with  Mind, 
involves  in  the  first  place,  a  generation  of  nervous  force,  which  excites  muscular 
contraction;  secondly,  a  physical  change  determined  by  that  contraction,  the 
medium  of  which  may  be  sound,  light,  or  motion;  and  thirdly,  the  operation  of 
this  physical  change  as  an  "impression"  upon  the  sensory  nerves,  and  through 
them  upon  the  sensorial  ganglia,  of  the  other  party.     Such  is  the  case,  for  ex- 
ample, not  only  in  that  communication  which  takes  place  by  language,  whether 
written  or  spoken ;  but  in  the  look,  the  touch,  the  gesture,  which  are  so  fre- 
quently more  expressive  than  any  words  can  be;  and  thus  we  see  that  our 
interchange   of  ideas  and  emotions  which  are  most  purely  psychical  in  their 
nature,  can  only  be  accomplished  through  the  intermediation  of  physical  forces. 
That  imperfections  in  such  communication  are  thus  involved  in  the  very  nature 
of  our  present  condition,  and  that  all  the  higher  operations  of  the  mind  are 
trammelled  and  restricted  by  the  limited  powers  of  its  corporeal  instrument,  is 
a  matter  of  constant  and  indubitable  experience.     On  the  other  hand,  that,  in 
a  future  state  of  being,  the  communion  of  mind  with  mind  will  be  more  inti- 
mate, and  that  Man  will  be  admitted  into  more  immediate  converse  with  the 
Supreme  Intelligence,  appears  to  be  alike  the  teaching  of  the  most  comprehen- 
sive Philosophical  inquiries,  and  of  the  most  direct  Revelation  of  the  Divinity. 

391.  The  Organs  of  Sense  are  instruments,  which  are  adapted  to  enable  par- 
ticular nerves  to  receive  impressions  from  without;  of  a  kind,  and  in  a  degree, 
of  which  they  would  not  otherwise  be  sensible.     Thus,  although  the  simple 
mechanical  impression  produced  by  contact  of  a  hard  body,  produces  such  a 
change  in  it,  as,  being  propagated  to  the  central  sensorium,  excites  sensation 
there,  it  is  evident  that  a  nerve  must  be  peculiarly  modified  at  its  peripheral 
expansion  to  receive  its  impressions  from  the  undulations  of  the  air;  still  more, 
to  be  susceptible  of  the  impressions  produced  by  those  undulations  to  which 
most  Natural  Philosophers  now  attribute  the  transmission  of  light.     And,  even 
when  this  has  been  provided  for,  by  some  modification  in  the  structure  or  ar- 
rangements of  the  nerve-fibres  themselves,  or  of  the  vesicular  matter  in  con- 
nection with  them,  a  further  provision  is  still  required  for  giving  to  the  mind  a 
distinct  consciousness  of  external  objects  in  all  their  variety  of  shapes,  colors, 
lights,  and  shadows,  &c. ;  or  for  enabling  it  to  form  ideas  of  the  direction,  pitch, 
quality,  &c.,  of  sonorous  undulations.     There  is  reason  to  believe  that  many 
among  the  lower  Animals,  which  cannot  see  objects  around  them,  are  conscious  of 
the  influence  of  light;  and  thus  the  distinction  between  the  mere  reception  of  the 


FUNCTIONS    OP  ANIMAL   LIFE.  373 

impression,  and  the  excitement  of  a  visual  perception,  becomes  evident.  The 
former  may  take  place  through  the  intervention  of  nerves,  whose  sensory  ex- 
tremities offer  no  extraordinary  peculiarities :  the  latter  can  only  be  received 
through  the  medium  of  an  instrument,  which  shall,  from  the  mixture  of  rays 
falling  equally  upon  every  part  of  its  surface,  produce  an  optical  image,  and 
then  impress  it  upon  the  expanded  surface  of  the  nerve;  so  that,  each  fibril 
receiving  a  distinct  impression,  the  mind  may  form  its  picture  by  the  combina- 
tion of  the  whole.  That  this  is,  in  fact,  the  share  which  the  organs  of  Special 
Sense  bear  in  the  general  endowments  of  the  whole  apparatus,  may  be  inferred 
especially  from  the  conformation  of  the  Eye;  which  is  in  every  respect  a  merely 
optical  instrument,  of  the  greatest  beauty  and  perfection,  adapted  to  form  upon 
the  retina,  in  the  most  advantageous  manner,  the  images  of  surrounding  objects 
in  all  their  variations.  There  can  be  little  doubt  that  the  structure  of  the  Ear 
is  arranged  to  do  the  same  for  the  sonorous  vibrations  which  the  eye  does  for 
the  rays  of  light;  that, is,  through  its  means,  the  undulations  which  strike  upon 
the  external  surface  of  the  organ  are  separated  and  distinguished,  those  of  a 
like  kind  being  brought  together  upon  one  division  of  the  nerve,  and  those  of 
another  order  upon  a  different  set  of  fibres;  so  that  the  different  kinds  of  sound, 
and  the  peculiar  quality  and  direction  of  each,  may  be  discriminated;  whilst,  by 
the  concentration  of  all  the  impressions  of  the  same  character,  a  higher  amount 
of  force  is  given  to  them.  The  apparatus  which  ministers,  however,  to  the 
sense  of  Smell,  is  far  less  complete  in  its  endowments;  for  it  serves  only,  in 
Man  at  least,  for  the  discrimination  of  odorous  emanations,  and  affords  no 
guidance  with  regard  either  to  their  direction  or  their  source.  In  fact,  the  kind 
of  information  which  Man  receives  through  this  sense,  seems  very  much  akin 
to  that  which  the  lowest  animals  possessing  visual  organs  can  derive  from  their 
employment.  Still,  a  special  organ  of  sense  is  required,  to  enable  the  olfactive 
nerve  to  be  impressed  by  the  peculiar  agency  of  odorous  emanations ;  which, 
whatever  be  its  nature,  has  no  operation  upon  ordinary  sensory  surfaces.  It  is 
not  a  little  remarkable,  that  the  specialty  of  organization  of  the  nerves  of  Sight, 
Hearing,  and  Smell,  renders  them  incapable  of  receiving  ordinary  mechanical 
impressions;  so  that  the  contact  of  solid  substances  with  the  sensory  surfaces 
which  they  supply  is  not  felt,  except  through  the  instrumentality  of  other 
nerves;  and  no  irritation  of  their  trunks,  mechanical  or  otherwise,  gives  rise  to 
feelings  of  pain.  The  sense  of  Taste,  however,  though  special  in  regard  to  the 
peculiarity  of  the  impressions  which  its  organ  is  adapted  to  receive,  is  closely 
akin  to  that  of  Touch  in  the  conditions  under  which  it  is  exercised;  the  abso- 
lute contact  of  the  sapid  substance  with  the  sensory  surface  being  requisite ;  and 
the  papillary  organs  in  which  the  gustative  nerves  may  be  said  to  originate, 
being  essentially  the  same  in  structure  with  those  of  ordinary  tactile  surfaces. 

392.  The  Brain  and  Spinal  Cord  of  Man,  in  which  by  far  the  greater  part 
of  the  afferent  nerves  terminate,  and  from  which  nearly  all  the  motor  nerves 
arise,  may  be  considered  as  made  up  of  an  aggregation  of  a  number  of  distinct 
ganglionic  centres,  each  of  which  has  its  own  special  endowments,  and  is  con- 
nected with  nervous  trunks  of  its  own.  Commencing  with  the  Spinal  Cord, 
we  find,  on  comparing  it  with  the  gangliated  column  of  Articulated  animals, 
that  it  really  consists  of  a  series  of  ganglia  disposed  in  a  longitudinal  line,  which 
have  coalesced  with  each  other;  each  ganglion  being  the  centre  of  the  "nervous 
circle"  proper  to  one  vertebral  segment  of  the  trunk.  Throughout  the  entire 
series,  we  find  no  other  endowment  than  that  of  reacting  upon  an  excitant ;  this 
excitant  being  either  conveyed  by  the  afferent  nerve-trunks,  or  transmitted 
downwards  from  the  higher  parts  of  the  nervous  system.  No  impression  which 
is  limited  to  this  series  of  ganglia,  excites  any  sensorial  change;  so  that  we 
may  consider  the  Spinal  Cord  as  the  special  instrument  of  the  "  excito-motor" 
division  of  the  functions  of  the  nervous  system.  The  ordinary  Spinal  Nerves 


374  GENERAL   VIEW   OF   THE    HUMAN   FUNCTIONS. 

are  distributed  to  the  sensory  surfaces  and  to  the  muscular  apparatus  of  the 
body  generally;  but  at  the  summit  of  the  Cord  we  find  a  peculiar  set  of  gan- 
glionic  centres,  included  in  that  part  which  is  distinguished  as  the  Medulla 

Oblongata,  whose  nerves  are  distributed  to  the  organs  of  Respiration,  Deglu- 
tition, &c.,  and  whose  function  consists  in  sustaining  the  muscular  move- 
ments whose  performance  is  essential  to  the  continuance  of  these  functions. 
The  movements  in  question  are  purely  reflex;  and  there  is  no  other  reason  for 
distinguishing  the  endowments  of  the  Medulla  Oblongata  from  those  of  the 
Spinal  Cord,  save  that  which  arises  out  of  the  specialty  of  the  purposes  to  which 
the  movements  are  subservient.  At  the  summit  of  the  Spinal  Cord,  and  partly 
lodged  in  the  substance  of  the  Medulla  Oblongata,  we  find  the  series  of  Sensory 

Ganglia,  which  may  in  their  totality  be  considered  as  making  up  the  Sensorium. 
This  includes  the  centres  to  which  proceed  the  nerves  of  "  special  sense ;"  and 
we  may  probably  rank  with  it  a  pair  of  ganglionic  masses  (the  "  thalami  optici,") 
towards  which  certain  afferent  fibres  of  the  spinal  trunks  appear  traceable,  that 
do  not  find  their  ganglionic  centre  in  the  spinal  ganglia,  but  seem  to  pass  up- 
wards to  the  sensorium,  that  they  may  there  excite  sensational  changes  of  the 
"  common"  or  tactile  kind.  From  these  Sensory  Ganglia,  we  do  not  find  any 
motor  trunks  ostensibly  originating;  but  fibres  pass  downwards  from  them  into 
the  Spinal  cord,  which  either  directly  enter  its  efferent  nerve-trunks,  or  which 
serve  to  excite  to  action  the  ganglia  from  which  those  trunks  arise;  so  that 
"  reflex"  actions  are  performed  by  the  instrumentality  of  the  sensorial  ganglia, 
which,  however,  differ  from  those  of  the  spinal  cord,  in  requiring  Sensation  as  a 
necessary  link  in  the  series  of  changes.  The  Sensory  ganglia  are,  therefore,  the 
centres  of  the  consensual  or  sensori-motor  actions.  The  whole  of  this  series  of 
ganglionic  centres  constitutes  the  purely  automatic  portion  of  the  Nervous  sys- 
tem, whose  operations,  when  not  interfered  with  by  the  Cerebrum,  are,  like 
those  of  Insects  (whose  entire  nervous  system  corresponds  with  the  automatic 
portion  of  that  of  Man),  entirely  instinctive.  And  their  independent  action 
seems  to  be  the  source,  not  merely  of  all  those  movements  which  are  originally 
instinctive,  but  of  many  others  which  come  by  habit  to  be  performed  involun- 
tarily when  the  attention  is  otherwise  engaged;  these  have  been  termed  "  se- 
condarily automatic." 

393.  But  in  Man,  as  in  all  other  animals  possessed  of  Intelligence,  by  which 
the  Will  is  animated  and  directed,  we  find  a  superadded  organ,  the  Cerebrum, 
which  is  not  itself  the  centre  of  either  sensory  or  motor  nerves,  but  which  derives 
from  the  automatic  apparatus  just  described  all  its  stimulus  to  action,  and 
employs  it  as  its  instrument  of  operation  on  the  muscular  system.  The  functions 
of  this  organ,  which  are  purely  mental,  are  first  excited  by  the  sensations  called 
forth  in  the  Sensory  ganglia,  which,  being  conveyed  to  the  cerebrum,  give  rise 
through  its  instrumentality  to  Ideas ;  and  these  may  become  the  subject  of 
Reasoning  processes,  which  react  on  the  body  by  an  exertion  of  the  Will.  Al- 
though it  has  been  customary  to  regard  the  Will  as  directly  operating  on  the 
muscular  system,  yet  we  shall  hereafter  find  reason  to  consider  it  as  exerting  its 
power  through  the  medium  of  the  Automatic  apparatus,  to  which  its  determina- 
tions are  transmitted,  and  by  which  they  are  carried  into  execution.  But  ideas 
with  which  the  feelings  of  pleasure  or  pain  are  associated,  constitute  Emotions  ; 
and  these,  if  strongly  excited,  may  act  downwards  upon  the  muscles  through  the 
medium  of  the  automatic  apparatus,  quite  independently  of  the  will,  and  even 
in  opposition  to  it.  And  there  are  certain  peculiar  states  of  the  mind,  in  which 
the  power  of  the  Will  is  completely  suspended,  and  in  which  Ideas  alone  seem 
capable  of  exciting  movements.  Thus  the  Cerebral  ganglia  are  the  instruments 
of  two  kinds  of  action  that  may  be  considered  essentially  "reflex,"  as  being  ex- 
ecuted in  respondence  to  external  impressions,  without  any  volitional  or  purposive 
direction;  these  impressions  either  acting  simply  through  ideas,  and  thus  pro- 


NATURE   AND   DESTINATION   OF   FOOD.  375 

ducing  ideo-motor  actions,  or  through  ideas  with  which  feelings  are  associated, 
and  thus  producing  emotional  movements. 

394.  Another  division  of  the  Nervous  System  appears  to  have  for  its  object 
to  combine  and  harmonize  certain  muscular  movements  immediately  connected 
with  the  maintenance  of  Organic  life }  and  to  bring  these  into  relation  with  cer- 
tain conditions  of  the  mind.     There  is  further  reason  to  believe  that  it  also  in- 
fluences, and  brings  into  connection  with  each  other,  the  processes  of  Nutrition, 
Secretion,  &c. ;  though  these,  like  the  muscular  movements  just  mentioned,  are 
essentially  independent  of  it. — This  portion  of  the  nervous  apparatus  is  commonly 
known  under  the  name  of  the  Sympathetic  system ;  it  has  a  set  of  ganglionic 
centres  and  nerves  of  its  own  j  but  it  is  also  intimately  blended  with  the  Cerebro- 
spinal  system,  receiving  fibres  from  it,  and  also  sending  fibres  into  it. 

395.  With  reference  to  that  class  of  operations  of  which  the  Cerebrum  is  the 
instrument,  it  is  well  here  to  explain  that,  though  the  Physiologist  speaks  of  the 
intellectual  powers,  moral  feelings,  &c.,  as  functions  of  the  Nervous  System,  they 
are  not  so  in  the  sense  in  which  the  term  is  employed  in  regard  to  other  opera- 
tions of  the  bodily  frame.     In  general,  by  the  function  of  an  organ,  we  under- 
stand some  change  which  may  be  made  evident  to  the  senses,  as  well  in  our  own 
system,  as  in  the  body  of  another.     Sensation,  Thought,  Emotion,  and  Volition, 
however,  are  changes  imperceptible  to  our  senses  by  any  means  of  observation 
we  at  present  possess.     We  are  cognizant  of  them  in  ourselves,  without  the 
intervention  of  those  processes  by  which  we  observe  material  changes  external 
to  our  minds ;  but  we  judge  of  them  in  others,  only  by  inferences  founded  on 
the  actions  to  which  they  give  rise,  when  compared  with  our  own.     When  we 
speak  of  sensation,  thought,  emotion,  or  volition,  therefore,  as  functions  of  the 
Nervous  System,  we  mean  only  that  this  system  furnishes  the  conditions  under 
which  they  exist  in  the  living  body ;  and  we  leave  the  question  entirely  open, 
whether  the  "VVM  has  or  has  not  an  existence  independent  of  that  of  the  material 
organism,  by  which  it  operates  in  Man,  as  he  is  at  present  constituted. 


CHAPTER  VII. 

OF  FOOD,  AND  THE  DIGESTIVE  PROCESS. 

1.    Of  Food,  its  Nature  and  Destination. 

396.  THE  substances  which  are  required  by  Animals  for  the  development  and 
maintenance  of  their  fabric,  are  of  two  kinds :  the  Organic  and  the  Inorganic. 
The  Organic  alone  are  commonly  reckoned  as  aliments  ;  but  the  latter  are  really 
not  less  requisite  for  the  sustenance  of  the  body,  which  speedily  disintegrates,  if 
the  attempt  be  made  to  support  it  upon  any  organic  compounds  in  a  state  of 
purity.     In  all  ordinary  articles  of  diet,  however,  the  Inorganic  matters  are 
present  in  the  requisite  proportion ;  and  hence  they  have  very  commonly  escaped 
notice.     The  nature  of  these  substances,  and  the  mode  in  which  they  are  intro- 
duced into  the  body,  have  been  already  treated  of  (CHAP.  n.  SECT.  6). 

397.  The  Organic  compounds  usually  employed  as  food  by  Man,  are  partly 
derived  from  the  Animal,  and  partly  from  the  Vegetable  kingdom;  and  they 
may  be  conveniently  arranged  under  the  four  following  heads:1  1.  The  Saccha- 

1  Dr.  Prout's  classification  of  alimentary  substances  is  here  adopted,  with  a  slight  modi- 
fication; not  as  being  altogether  unexceptionable,  but  as  being,  in  the  Author's  opinion,  the 
most  convenient  hitherto  proposed. 


376  OF   FOOD,    AND   THE   DIGESTIVE   PROCESS. 

rine  group,  including  all  those  substances,  derived  from  the  Vegetable  kingdom, 
which  are  analogous  in  their  composition  to  Sugar;  consisting  of  oxygen, 
hydrogen,  and  carbon  alone ;  and  having  the  first  two  present  in  the  proportions 
to  form  water.  To  this  group  belong  starch,  gum,  woody  fibre,  and  the  cellulose 
of  Plants,  which  closely  resemble  each  other  in  the  proportion  of  their  elements, 
and  which  may  be  converted  into  Sugar  by  chemical  processes  of  a  simple  kind ; 
whilst  Alcohol,  which  is  derived  from  Sugar  by  the  process  of  fermentation,  has 
a  composition  which  rather  connects  it  with  the  next  group. — 2.  The  Oleaginous 
group,  including  oily  matters,  whether  derived  from  the  Vegetable  kingdom,  or 
from  the  fatty  portions  of  Animal  bodies.  The  characteristic  of  this  class  lies 
in  the  great  predominance  of  hydrogen  and  carbon,  the  small  proportion  of 
oxygen,  and  the  entire  absence  of  nitrogen. — 3.  The  Albuminous  group,  com- 
prising all  those  substances,  whether  derived  from  the  Animal  or  the  Vegetable 
kingdom  which  are  closely  allied  to  Albumen,  and  through  it  to  the  Animal 
tissues  generally  (§  20),  in  their  chemical  composition.  In  this  group,  a  large 
proportion  of  azote  is  united  with  the  oxygen,  hydrogen,  and  carbon  of  the  pre- 
ceding.— 4.  The  Gelatinous  group,  consisting  of  substances  derived  from  Animal 
bodies  only,  which  are  closely  allied  to  Gelatin  in  their  composition.  These 
also  contain  azote;  but  the  proportion  of  their  components  differs  from  that  of 
the  preceding. — There  are  many  other  substances,  however,  which,  though  truly 
alimentary,  and  consumed  to  a  considerable  amount,  cannot  be  legitimately 
placed  under  either  of  the  above  heads }  such  are,  for  example,  the  Vegetable 
Acids. 

398.  The  compounds  of  the  Saccharine  group  cannot,  without  undergoing 
metamorphosis,  form  part  of  any  Animal  tissue ;  as  there  is  none  which  they  at 
all  resemble  in  composition.     It  has  been  shown,  however,  that  they  are  con- 
vertible, within  the  animal  body,  into  those  of  the  Oleaginous  group  (§  40),  and 
may  thus,  like  the  latter,  be  applied  to  the  formation  of  the  Adipose  and  Ner- 
vous tissues.     But  the  amount  of  these  substances  which  is  thus  employed,  is  a 
very  small  part  of  that  which  is  ordinarily  introduced  as  food;  and  by  far  the 
larger  proportion  of  them  is  made  subservient  to  the  maintenance  of  the  Heat 
of  the  body  by  the  combustive  process.     The  Sugar  which  is  taken  in  as  such, 
being  dissolved  and  absorbed  into  the  current  of  the  circulation,  appears  to 
undergo  a  speedy  metamorphosis  into  lactic  acid,  which  is  the  form  under  which 
it  is  finally  oxidized  and  burned  off  (§  49) ;  and  Starch  is  made  capable  of 
undergoing  the  same  change,  by  being  first  converted  into  Sugar  during  the 
digestive  process.     Oleaginous  matters  do  not  seem  to  undergo  any  change  pre- 
liminary to  their  oxidation,  save  their  reduction  to  a  state  of  very  fine  division. 
— We  shall  presently  see   (§  401)  that  a  very  considerable  difference  exists 
between  the  Saccharine  and  Oleaginous  matters,  in  regard  to  their  relative 
calorifying  powers. — That  none  of  these  non-azotized  substances  can  be  made 
capable,  by  metamorphosis  or  combination  within  the  Animal  body,  of  taking 
the  place  of  the  azotized  substances  as  "  histogenetic"  or  "  plastic"  compounds, 
may  now  be  regarded  as  one  of  the  most  certain  facts  in  Physiology;  the  con- 
current evidence  of  experiment  and  observation  leading  to  the  conclusion  that 
in  Plants  alone  can  any  production  of  azotized  compounds  take  place,  and  that 
Animals  are  in  consequence  directly  or  indirectly  dependent  upon  the  Vegetable 
kingdom  for  their  means  of  subsistence.     If  animals  be  fed  exclusively  upon 
Saccharine  or  Oleaginous  substances,  of  any  kind  or  in  any  combination  what- 
ever, they  speedily  perish  with  symptoms  of  Inanition ;  and  the  only  assistance 
which  such  food  affords  in  the  prolongation  of  life,  is  derived  from  its  calorific 
power  (§  375). 

399.  The  application   of  the  substances  forming  the  Albuminous  group,  to 
the  support  of  the  Animal  body,  by  affording  the  materials  for  the  nutrition 
and  re -formation  of  its  tissues,  and  also  for  the  maintenance  of  its  heat,  has 


NATURE   AND   DESTINATION   OF   FOOD.  377 

been  already  sufficiently  considered  (CHAP.  n).  The  proportions  of  carbon, 
hydrogen,  oxygen,  and  nitrogen,  of  which  all  these  substances  are  composed, 
appear  to  be  identical;  and  they  are  all  capable  of  being  reduced  by  the  digestive 
process  to  the  condition  of  albumen.  Hence  it  is  a  matter  of  little  consequence, 
except  as  regards  the  proportions  of  inorganic  matters  with  which  they  may  be 
respectively  united,  whether  we  draw  our  histogenetic  materials  from  the  flesh 
of  animals,  from  the  white  of  egg  (albumen),  from  the  curd  of  milk  (casein), 
from  the  grain  of  wheat  (gluten),  or  from  the  seed  of  the  pea  (legumin). 
Neither  of  these  substances,  however,  can  long  sustain  life  when  it  is  used  by 
itself;  for  it  has  been  experimentally  ascertained  that,  by  being  made  to  feed 
constantly  on  the  same  substance — boiled  white  of  egg,  for  instance,  or  meat 
deprived  of  the  principle  (osmazome)  that  gives  it  flavor — an  animal  may  be 
effectually  starved;  its  disgust  at  such  food  being  such  that,  even  if  this  be 
swallowed,  it  is  not  digested.1  The  organized  fabric  of  Animals  contains,  as  we 
have  seen,  a  large  quantity  of  Gelatin.  It  seems  certain  that  this  substance 
may  be  produced  out  of  fibrin  and  albumen ;  since  in  animals  that  are  supported 
on  these  alone,  the  nutrition  of  the  gelatinous  tissues  does  not  seem  to  be  im- 
paired. But  it  has  been  commonly  supposed  that  gelatin  taken  in  as  food  may 
serve  for  the  growth  and  maintenance  of  these  tissues ;  even  though  it  may  be 
incapable  of  conversion  to  the  albuminous  type.  It  is  very  doubtful,  however, 
whether  Gelatin  can  render  even  this  service.  For  all  our  knowledge  of  the 
history  of  the  development  of  the  Gelatinous  tissues  would  lead  us  to  regard 
them  as  secondary  products,  which  take  their  origin  in  a  fibrinous  blastema,  and 
can  only  be  generated  by  the  metamorphosis  of  protein  compounds  (§§  28,  29, 
222,  223).  If  these  views  be  correct,  it  follows  that  the  alimentary  value  of 
gelatin  must  be  limited  to  its  calorific  power ;  its  hydrocarbon  being  separated 
from  its  highly  azotized  portion,  and  the  former  being  oxidized  and  eliminated 
through  the  lungs,  whilst  the  latter  will  pass  off  by  the  kidneys.  And  this 
view  is  confirmed  by  the  observations  of  Frerichs  on  the  result  of  the  ingestion 
of  large  quantities  of  pure  gelatin;  this  being  a  marked  increase  in  the  propor- 
tion of  urea  in  the  urine,  with  an  elevation  of  its  specific  gravity  from  1018  to 
1030  or  even  1034.  Neither  Leucine  nor  Glycine  could  be  detected  in  the 
fluid;  so  that  Gelatin  seems  to  be  subjected  to  the  same  metamorphosis  that 
the  protein  compounds  undergo  when  they  are  taken  in  excess.2 — That  Gelatin 
cannot  take  the  place  of  the  albuminous  compounds,  has  been  fully  demon- 
strated by  the  inquiries  of  the  Commissions  which  have  been  appointed  to  in- 
vestigate the  subject  in  Paris  and  Amsterdam.3  In  so  far,  therefore,  as  the 
only  azotized  principles  contained  in  soups,  broths,  &c.,  are  of  the  gelatinous 
character,  we  must  account  these  preparations  as  destitute  of  the  power  of 
nourishing  the  body ;  and  the  peculiar  nutritive  value  which  experience  shows 
that  such  preparations  possess  in  certain  states  of  the  system,  must  be  attributed 
to  the  albuminous  matters  which  they  hold  in  solution,  and  to  the  readiness 

1  It  is  very  interesting  to  remark  (with  Dr.  Prout)  that,  in  the  only  instance  in  which 
Nature  has  provided  a  single  article  of  food  for  the  support  of  the  animal  body,  she  has 
mingled  articles  from  the  three  first  of  the  preceding  groups.     This  is  the  case  in  Milk, 
which  contains  a  considerable  quantity  of  an  albuminous  substance,  casein,  which  forms 
its  curd ;  a  good  deal  of  oily  matter,  the  butter ;  and  no  inconsiderable  amount  of  sugar, 
which  is  dissolved  in  the  whey.     The  proportions  of  these  vary  in  different  Mammalia  ; 
and  they  depend  in  part  upon  the  nature  of  the  food  supplied  to  the  Animal  that  forms 
the  milk  ;  but  the  substances  are  thus  combined  in  every  instance. 

2  See  Frerichs's  article    Verdauung  in  "Wagner's  Handworterbuch." — The  Author  is 
indebted  to  Dr.  Gull  for  directing  his  attention  to  this  view  of  the  incapacity  of  Gelatin 
for  any  histogenetic  purpose. 

3  See  the  Report  of  the  French  "Gelatin  Commission,"  in  the  "  Compt.  Rend."  Aout, 
1841;  and  that  of  the  Amsterdam  Commission  in  "Het.  Instituut,"  No.  2,  1843,  and 
"Gazette  Medicale,"  Mars  16,  1844. 


378 


OF  FOOD,  AND  THE  DIGESTIVE  PROCESS. 


with  which  their  gelatinous  constituents  are  absorbed  and  applied  (by  the  decom- 
position just  explained)  to  the  purpose  of  calorification.1 

400.  The  substances  which  cannot  be  arranged  under  either  of  the  preceding 
groups,  are,  for  the  most  part,  of  the  non-azotized  class;  and,  as  they  mostly 
consist  of  compounds  in  which  the  hydrogen  and  carbon  are  not  combined  with 
their  full  equivalents  of  oxygen,  they  are  made  to  contribute  to  the  calorifying 
process  by  undergoing  oxidation  within  the  system,  so  as  to  be  excreted  in  the 
form  of  carbonic  acid  and  water. 

401.  By  rules  based  on  the  foregoing  data,  then,  we  may  estimate  the  rela- 
tive value  of  different  articles  of  food  for  the  two  distinct  purposes  of  tissue- 
formation  and  the  production  of  heat.     For  the  proportion  of  albuminous  matter 
which  any  substance  may  contain,  furnishes  the  measure  of  its  histogenetic 
value;  whilst  the  proportion  of  hydro-carbon  uncombined  with  oxygen  affords 
the  means  of  estimating  its  calorific  power  when  oxidized.     As  in  almost  every 
alimentary  substance,  whether  vegetable  or  animal,  the  two  classes  of  compounds 
are  mingled,  the  percentage  of  Nitrogen  which  it  may  contain  affords  a  tolerably 
correct  measure  of  the  amount  of  albuminous  matter  which  it  includes,  and 
therefore  of  its  histogenetic  value  :  where,  on  the  other  hand,  the  percentage  of 
Nitrogen  is  the  smallest,  that  of  Hydro-carbon  is  the  largest,  and  the  proportion 
of  the  combustive  material  is  the  highest.     The  following  Table2  specifies  this 
proportion  in  the  case  of  various  articles  used  as  food;  Human  Milk  being  taken 
as  the  standard  of  comparison,  and  the  quantity  of  Nitrogen  it  contains  being 
expressed  by  100.     It  must  be  born  in  mind,  however,  that  this  substance  is 
intended  for  the  nourishment  of  a  being,  that  passes  nearly  the  whole  of  its  time 
in  a  quiescent  state ;  and  must  not  be  supposed  to  be  adapted  for  the  sole  main- 
tenance of  the  Human  body  in  a  state  of  activity.     In  fact,  it  is  inferior  in  its 
proportion  of  Casein  (the  substance  of  which  alone  the  azote  forms  a  part)  to 
the  milk  of  most,  if  not  all,  other  Mammalia ;  their  young  bringing  their  animal 
functions  into  exercise  at  a  much  earlier  period  than  does  the  Human  infant. 

Vegetable. 


Rice    . 

.     81 

Potatoes      . 

.     84 

Turnips 

.  106 

Rye     . 

.  106 

Maize 

100-125 

Barley 

.  125 

Human  Milk 

.  100 

Cow's  Milk 

.  237 

Oyster 

.  305 

Yolk  of  Eggs       . 

.  305 

Cheese 

331-447 

Eel,  raw      . 

.  434 

boiled  . 

.  428 

Liver  of  Crab 

.  471 

Mussel,  raw 

.  528 

hnilrd 

(ifiO 

Ox  Liver,  raw 

.    uuv/ 

.  570 

Pork-ham,  raw    . 

.  639 

boiled 

.  807 

.     81 
.     84 
.  106 
.  106 
100-125 
.  125 

Oats        .   :      .         .138 
White  bread     .         .  142 
Wheat       .         .  119-144 
Carrots    .         .         .150 
Brown  bread    .         .  166 
Agaricus  cantharellus  201 

Peas   . 
Agaricus  russula. 
Lentils 
Haricot  beans 
Agaricus  deliciosus 
Beans           .         . 

.  239 
.  264 
.  276 
.  283 
.  289 
.  320 

Animal. 
Salmon,  raw    . 

.  776 
.  610 
.  742 
•  764 
.  845 
.  859 
.  §59 
.  956 
.  916 
.  808 
.  924 
.  920 
.  816 

Liver  of  Pigeon 
Portable  soup  . 
White  of  Egg  . 
Crab,  boiled     . 
Skate,  raw 
boiled  . 
Herring,  raw   . 
boiled 

TYlllt    of 

Haddock,  raw  . 
boiled 

Flounder,  raw     .  ,    ;  rt 
hmlrfl 

898 
0^4 

UOIlt/U. 

Pigeon,  raw 
boiled 

VO^ 

756 
827 

Lamb,  raw  . 
Mutton,  raw 
boiled 

833 
773 

852 

Veal,  raw    . 
boiled 
Beef,  raw    . 
boiled 
Ox  lung 

873 
911 
880 
942 
931 

1  The  common  notion  of  the  great  nutritive  value  of   soups,   &c.,  whose    supposed 
"  strength"  is  indicated  by  the  firmness  with  which  they  gelatinize  on  cooling,  is  one  of 
those  popular  dietetic  prejudices,  of  which  it  is  peculiarly  incumbent  on  the  Medical  Pro- 
fession to  disabuse  their  patients. 

2  Schlossberger  and  Kemp,  in  "Philosophical  Magazine,"  Nov.  1845. 


NATURE   AND   DESTINATION    OF   FOOD.  S9 

It  is  not  to  be  supposed,  however,  that  any  table  of  this  kind,  founded  simply 
upon  the  Chemical  composition  of  the  various  substances,  can  indicate  their 
respective  fitness  as  articles  of  diet;  since  this  depends  also  upon  the  facility 
with  which  they  are  reduced  by  the  digestive  process,  and  afterwards  assimilated. 
Thus  an  aliment,  abounding  in  nutritive  matter,  may  be  inferior  to  one  which 
really  contains  a  much  smaller  proportion,  if  only  a  part  in  the  first  case,  and 
the  whole  in  the  second,  be  readily  taken  up  by  the  system. — The  calorific 
powers  of  the  substances  above  enumerated,  however,  are  not  precisely  in  the 
inverse  ratio  to  their  histogenetic  value ;  for,  as  the  amount  of  heat  given  off  in 
their  combustion  depends,  not  simply  upon  the  amount  of  carbon  and  hydrogen 
they  may  contain,  but  upon  the  amount  of  their  hydro-carbon  over  and  above 
that  which  is  already  combined  with  oxygen,  substances  that  are  alike  deficient 
in  nitrogen  may  differ  considerably  in  this  respect.  Thus  in  ordinary  fat,  the 
proportion  of  oxygen  is  only  about  10  per  cent.,  whilst  that  of  hydro-carbon  is 
at  least  90  per  cent.;  in  alcohol,  the  proportion  of  oxygen  is  nearly  35  per  cent, 
to  65  per  cent,  of  hydro-carbon;  in  starch,  the  oxygen  is  49£  per  cent.,  the 
hydro-carbon  50f  per  cent. ;  in  cane-sugar,  the  oxygen  is  51  ?,  the  hydro-carbon 
48  i  ;  and  in  grape  sugar,  the  oxygen  is  53  i,  the  hydro-carbon  46f .  According 
to  the  estimate  of  Prof.  Liebig/  the  following  are  the  relative  calorific  powers 
of  these  substances,  the  numbers  expressing  approximately  the  weights  of  each 
which  must  be  taken  in  as  food,  in  order,  with  the  same  consumption  of  oxygen 
to  keep  the  body  at  its  proper  temperature  during  equal  times;  fat,  100;  starch, 
240 ;  cane-sugar,  249 ;  grape-sugar,  263  ;  spirits  (containing  50  per  cent,  of  ab- 
solute alcohol),  266.  The  equivalent  of  lean  flesh  required  to  produce  the  same 
calorific  effect  with  the  foregoing,  would  be  no  less  than  770. 

402.  It  is  obvious  that  the  most  economical  diet  will  be  that  in  which  there 
is  the  most  perfect  apportionment  of  each  class  of  constituents  to  the  wants  of 
the  system;  and  these,  on  the  principles  formerly  explained  (§§  374-6),  will 
vary  with  the  amount  of  muscular  exertion  put  forth,  and  the  lowering  of  the 
external  temperature.  Thus,  for  a  man  of  ordinary  habits,  and  living  under  a 
medium  temperature,  a  diet  composed  of  animal  flesh  alone  is  the  least  econo- 
mical that  can  be  conceived;  for,  since  the  greatest  demand  for  food  in  his  sys- 
tem is  created  by  the  necessity  for  a  supply  of  carbon  and  hydrogen  to  support 
his  respiration,  this  want  may  be  most  advantageously  fulfilled  by  the  employ- 
ment of  a  certain  quantity  of  non-azotized  food,  in  which  these  ingredients  pre- 
dominate. Thus  it  has  been  calculated,  that,  since  fifteen  pounds  of  flesh  con- 
tain no  more  carbon  than  four  pounds  of  starch,  a  savage  with  one  carcass  and 
an  equal  weight  of  starch,  could  support  life  for  the  same  length  of  time,  during 
which  another  restricted  to  animal  food  would  require  five  such  carcasses,  in 
order  to  procure  the  carbon  necessary  for  respiration.  Hence  we  see  the  im- 
mense advantage  as  to  economy  of  food,  which  a  fixed  agricultural  population 
possesses  over  those  wandering  tribes  of  hunters,  which  still  people  a  large  part 
both  of  the  old  and  new  continents.  The  mixture  of  the  azotized  and  non- 
azotized  compounds  (gluten  and  starch),  that  exists  in  wheat  flour,  seems  to  be 
just  that  which  is  most  generally  useful  to  Man;  and  hence  we  see  the  explana- 
tion of  the  fact  that,  from  very  early  ages,  bread  has  been  regarded  as  the  "  staff 
of  life." — There  are  particular  conditions  of  existence,  however,  under  which 
life  may  be  advantageously  supported  upon  animal  food  alone.  Thus  the  Gua- 
chos  of  South  America,  who  pass  the  whole  day  in  the  saddle,  and  lead  a  life  of 
constant  activity  resembling  that  of  a  carnivorous  animal,  scarcely  ever  taste 
anything  but  beef;  and  of  this  their  consumption  is  by  no  means  great;  for  the 
temperature  of  the  surrounding  atmosphere  is  so  high,  that  the  body  has  no 
occasion  to  generate  more  heat  than  is  supplied  by  the  combustion  of  the  hydro- 

1  "Familiar  Letters  on  Chemistry,"  3d  edit.,  p.  380. 


380  OF   FOOD,    AND   THE   DIGESTIVE   PROCESS. 

carbonaceous  portion  of  the  "  waste"  of  the  tissues.  Here,  then,  the  demand 
for  histogenetic  material  being  at  its  maximum,  and  that  for  combustive  mate- 
rials at  its  minimum,  the  former  supplies  all  that  is  requisite  for  the  latter. 
Again,  the  Esquimaux  and  other  dwellers  upon  the  Arctic  seas  find  in  the  bodies 
of  the  whales,  seals,  &c.,  whereon  they  subsist,  that  special  supply  of  the  very 
best  combustive  material,  which  alone  can  enable  them  to  maintain  their  exist- 
ence in  a  climate  where  the  thermometer  is  for  many  weeks  or  months  in  the 
year  at — 40°  or  even  lower,  and  where  the  amount  of  heat  which  must  be  gene- 
rated within  the  body  is  four  or  five  times  that  for  which  a  diet  of  bread  will 
suffice. — On  the  other  hand,  the  general  experience  of  the  inhabitants  of  warm 
climates  seems  in  favor  of  a  diet  chiefly  or  entirely  vegetable;  and  its  peculiar 
suitableness  appears  to  consist  in  its  affording  an  adequate  supply  of  the  plastic 
alimentary  substances,  in  combination  with  farinaceous  matters  that  give  the 
requisite  bulk  to  the  food  (§  448),  without  affording  more  combustive  material 
than  the  system  requires — the  quantity  of  starch  which  undergoes  conversion, 
and  is  introduced  as  sugar  into  the  circulation,  being  apparently  governed  rather 
by  the  demands  of  the  respiratory  process,  than  by  the  amount  ingested,  and 
the  remainder  being  voided  again  unchanged. 

403.  The  mixed  diet,  to  which  the  inclination  of  Man  in  temperate  climates 
seems  usually  to  lead  him  (when  circumstances  allow  that  inclination  to  develop 
itself  freely),  appears  to  be  fully  conformable  to  the  construction  of  his  dental 
and  digestive  apparatus,  as  well  as  to  his  instinctive  propensities.  And  whilst 
on  the  one  hand  it  may  be  freely  conceded  to  the  advocates  of  "  Vegetarianism," 
that  a  well-selected  vegetable  diet  is  capable  of  producing  (in  the  greater  num- 
ber of  individuals)  the  highest  physical  development  of  which  they  are  capable, 
it  may  on  the  other  hand  be  affirmed  with  equal  certainty,  that  the  substitution 
of  a  moderate  proportion  of  animal  flesh  is  in  no  way  injurious,  whilst,  so  far  as 
our  evidence  at  present  extends,  this  seems  rather  to  favor  the  highest  mental 
development.  If,  indeed,  we  take  a  comprehensive  survey  of  the  conditions  of 
the  various  races  of  Man  at  present  inhabiting  the  earth,  we  cannot  help  being 
struck  with  his  adaptiveness  to  a  great  variety  of  circumstances,  as  regards  cli- 
mate, mode  of  life,  diet,  &c.  And  we  can  scarcely  avoid  the  conclusion,  that 
the  Creator,  by  conferring  upon  him  such  an  adaptiveness,  intended  to  qualify 
him  for  subsisting  on  those  articles  of  diet,  whether  animal  or  vegetable,  which 
are  most  readily  attainable  in  different  parts  of  the  globe;  and  thus  to  remove 
the  obstacle  which  a  necessary  restriction  to  any  one  kind  of  food  would  have 
otherwise  opposed  to  his  universal  diffusion.  If  we  were  to  bring  together  the 
habitual  diet-scales  of  the  several  races  of  men  which  people  the  surface  of  our 
globe,  we  apprehend  that  the  diversities  which  they  would  present  would  be 
scarcely  less  strange  than  those  which  exist  among  the  regimens  of  the  most 
dissimilar  species  of  Mammalia.  We  should  find  the  purely  animal-feeding  on 
the  one  hand,  the  pure  vegetarians  on  the  other.  Among  the  former  we  should 
find  some  who  devour  animal  flesh,  others  fish,  and  others  fowl,  while  others  are 
even  insectivorous ;  then,  again,  we  should  encounter  some  who  devour  their  food 
raw,  others  who  cook  it;  some  preferring  it  immediately  that  it  has  ceased  to  live, 
while  others  do  not  relish  it  until  it  has  become  almost  putrescent.  So  among  the 
vegetable-feeders,  we  should  find  some  subsisting  upon  soft  fruits,  others  upon  hard 
grains,  others  again  chiefly  upon  succulent  herbage,  and  others  upon  roots  so  tough 
as  to  require  artificial  means  for  their  reduction.  In  the  various  devices  by  which 
man  has  succeeded  in  availing  himself  of  these,  and  in  the  various  tastes  which 
have  led  some  to  avail  themselves  of  articles  of  food  which  others  would  loathe, 
we  see  the  evidence  of  the  same  wise  Design,  as  that  which  has  given  to  different 
tribes  of  animals  their  respective  preferences;  and  we  deduce  from  the  whole  the 
conclusion,  that  Man  is  left  by  his  Creator  at  perfect  liberty  to  select  that  kind  of 
nutriment  which  he  finds  most  suitable  to  his  tastes  and  to  his  wants;  the  former, 


NATURE   AND    DESTINATION    OF    FOOD.  381 

when  not  absolutely  vicious,  being  (there  is  strong  reason  to  believe)  an  expo- 
nent of  the  latter,  just  as  the  simple  desire  for  food  is  the  exponent  of  the  need 
for  it  in  the  system. 

404.  When  the  'results  of  experience,  then,  are  combined  with  the  teachings 
of  science,  they  seem  to  justify  the  following  conclusions. 

I.  That  a  due  adjustment  of  the  Albuminous,  Oleaginous,  and  Saccharine  con- 
stituents of  the  food,  to  the  varying  conditions  under  which  Man  exists,  is  of 
the  first  importance ;  and  that  the  question  of  the  derivation  of  the  first  two  of 
these  constituents  from  the  Animal  or  from  the  Vegetable  kingdom  is  one  of 
secondary  character  j  each  being  capable  of  yielding  them  in  adequate  amount, 
and  the  only  condition  requisite  being,  that  the  articles  of  food  shall  be  so  selected 
as  to  supply  the  needful  quantity.  Thus  a  diet  whose  staple  consists  of  potatoes 
or  rice,  contains  by  far  too  small  an  amount  of  albuminous  matter  in  proportion 
to  the  farinaceous  ;  but  if  to  this  be  added  a  moderate  quantity  of  meat,  the  pro- 
portion is  assimilated  to  that  which  exists  in  wheaten  bread,  which  may  be  taken 
as  the  standard  for  Man's  alimentation  in  all  but  extremely  cold  climates.  The 
failure  of  wheaten  bread  to  supply  what  the  system  there  requires,  depends  on 
nothing  else  than  its  deficiency  in  the  oleaginous  constituent  j  for  although  such 
a  craving  for  fat  meat  is  experienced  by  travellers  in  those  climates,  as  has  led 
to  the  belief  that  it  is  necessary  for  their  support,  yet  recent  experience  has  shown 
'that  a  vegetable  oil  answers  the  same  purpose,  bread  made  from  maize  flour 
(which  contains  a  large  proportion  of  oleaginous  matter)  having  been  found  to 
be  just  as  efficacious  as  fat  meat,  both  in  supporting  the  muscular  strength,  and 
in  maintaining  the  heat  of  the  body.1  On  the  other  hand,  maize-bread  is  found 
by  experience  to  be  far  less  adapted  than  wheaten  bread  for  consumption  in  warm 
climates,  being  too  "  heating"  in  its  character  ;  thus  confirming  the  view  already 
stated,  as  to  the  superiority  of  farinaceous  matter  as  the  principal  combustive 
material,  where  the  external  temperature  is  high. — The  same  kind  of  difference 
should  be  made  in  the  winter  and  summer  diet  of  the  inhabitants  of  the  tempe- 
rate zone.  For  when  the  external  temperature  is  low,  an  ample  supply  of  ole- 
aginous matter  is  indicated,  and  may  be  advantageously  taken  in  the  form  of  butter, 
cocoa,  fat  meat,  or  maize  bread.  On  the  other  hand,  during  the  heat  of  summer, 
the  more  nearly  the  diet  is  assimilated  to  that  of  the  natives  of  tropical  climates, 
in  the  substitution  of  fruits  and  farinacea  for  oleaginous  articles,  the  less  will  be 
the  liability  to  disordered  health  in  the  autumn.3 

n.  Experience  teaches,  however,  that  it  is  not  a  matter  of  entire  indifference, 
whether  the  Albuminous  constituent  be  drawn  from  the  Animal  or  from  the 
Vegetable  kingdom ;  for  the  use  of  a  highly-animalized  diet  has  a  tendency  to 
raise,  and  that  of  a  vegetable  diet  to  lower,  the  proportion  of  red  corpuscles  in 
the  Blood  (§  161) ;  whilst,  by  a  due  adjustment  of  the  proportion  of  the  two 
classes  of  components,  the  evil  effects  of  the  exclusive  use  of  either  may  be  pre- 
vented. 

1  The  Author  makes  this  statement  on  the  authority  of  Sir  J.  Kichardson,  who  informs 
him  that  2J  Ibs.  of  maize-flour  are  considered  to  be  the  equivalent  of  8  Ibs.  of  meat. 

2  There  can  be  no  doubt  that  a  large  proportion  of  the  diseases  of  the  digestive  apparatus, 
which  are  so  fatal  among  European  residents  in  India  and  other  tropical  climates,  result 
from  the  habitual  ingestion  of  a  much  larger  quantity  of  food,  and  this  especially  of  a  rich 
and  stimulating  character,  than  the  system  requires.     The  loss  of  appetite  consequent  upon 
the  diminution  of  the  demand  for  combustive  material,  is  set  down  to  the  deleterious  influence 
of  the  climate,  and  an  attempt  is  made  to  neutralize  this  by  artificial  provocatives. — So,  it 
seems  probable  that  many  of  the  "  bilious  attacks,"  which,  in  this  country,  are  so  frequent 
in  early  autumn,  and  which  are  commonly  set  down  to  the  account  of  fruit  (although  the 
subjects  of  them  have  often  abstained  entirely  from  that  article),  are  really  the  result  of 
the  presence  of  an  excess .  of  hydrocarbonaceous  matter  in  the  system,  consequent  upon 
over-feeding  during  the  summer,  and  must  be  looked  on  as  the  natural  means  by  which  it 
is  got  rid  of. 


382  OP   FOOD,    AND   THE   DIGESTIVE   PROCESS. 

in.  So,  again,  experience  teaches  what  could  scarcely  have  been  anticipated 
theoretically  ;  namely,  that,  notwithstanding  the  power  which  the  living  body 
possesses  of  converting  saccharine  compounds  into  oleaginous,  the  ingestion  of 
a  certain  amount  of  Oleaginous  matter  as  such  is  necessary,  or  at  least  is  favor- 
able, to  the  maintenance  of  health.  We  see  this  provided  in  large  quantity,  in 
the  first  aliment  prepared  by  nature  for  the  offspring  of  the  Mammalia ;  and  it 
exists  largely  in  the  yolk  of  the  egg  of  all  Oviparous  animals.  In  the  ordinary 
diet  of  every  nation  on  the  globe — whether  this  be  animal,  vegetable  or  mixed, 
— we  find  one  or  more  articles  of  an  oleaginous  nature  ;  and  there  is  a  natural 
craving  for  such  substances  when  they  are  completely  withheld,  which  indicates 
that  they  serve  some  important  purpose  in  the  economy.  Although  this  craving- 
is  so  far  affected  by  climate,  that  it  leads  to  the  largest  consumption  of  oily 
matter  where  the  extreme  of  cold  has  to  be  endured,  it  exists  with  no  less  in- 
tensity even  in  tropical  regions ;  and  we  find  the  Hindoo  adding  his  modicum  of 
"ghee"  (or  rancid  butter)  to  the  rice  which  constitutes  his  staple  article  of  diet, 
with  the  same  relish  that  the  Esquimaux  feels  for  his  massive  lumps  of  blubber. 
— It  does  not  seem  difficult  to  understand  the  rationale  of  this  fact.  It  has  been 
already  pointed  out,  that  whilst  the  Adipose  and  Nervous  tissues  are  the  only 
portions  of  the  Animal  fabric  into  which  fatty  matter  enters  in  any  considerable 
proportion,  yet  that  its  presence  has  an  important  influence  on  the  assimilation 
of  albuminous  matters,  and  seems  essential  to  every  act  of  cytogenesis  (§  42). 
We  shall  hereafter  see  (CHAP.  vin.  SECT.  3),  that  it  is  probably  in  the  Lacteal 
system  that  the  two  substances  are  brought  into  that  mutual  relation  with  each 
other  which  these  purposes  require  j  and  thus  it  is  obvious  that,  unless  a  con- 
version of  saccharine  into  oleaginous  matter  can  take  place  in  the  alimentary 
canal  (of  which  there  is  no  adequate  evidence),  no  true  chyle  can  be  formed,  ex- 
cept when  oleaginous  matters  have  formed  part  of  the  food.  There  is  strong  and 
increasing  reason  to  believe,  that  a  deficiency  of  oleaginous  matter,  in  a  state  fit 
for  appropriation  by  the  nutritive  processes,  is  a  fertile  source  of  diseased  action, 
especially  of  that  of  a  tuberculous  character;  and  that  the  habitual  use  of  it  in 
larger  proportion  would  operate  favorably  in  the  prevention  of  such  maladies, 
as  the  employment  of  cod-liver  oil  unquestionably  does  in  their  cure.  A  most 
remarkable  example  of  this  is  presented  by  the  population  of  Iceland ;  which, 
notwithstanding  the  concurrence  of  every  one  of  the  circumstances  usually  con- 
sidered favorable  to  the  scrofulous  diathesis,  enjoys  a  most  remarkable  immu- 
nity from  it — without  any  other  assignable  cause  than  the  peculiarly  oleaginous 
character  of  the  diet  usually  employed.1 

IV.  Another  of  the  results  of  experience,  of  which  Science  has  not  yet  given 
a  definite  rationale,  is  the  necessity  of  employing  fresh  vegetables  as  an  article  of 
Diet;  the  almost  invariable  consequence  of  the  entire  omission  of  them  being 
the  development  of  that  peculiar  constitutional  disorder  which  is  known  as 
Scurvy.  That  the  deficiency  of  something  which  fresh  vegetables  can  alone 
supply  is  the  essential  cause  of  this  disease  (its  operation  being  promoted,  how- 
ever, by  other  conditions,  such  as  absolute  deficiency  of  food,  confinement,  bad 
ventilation,  depression  of  spirits,  &c.),  may  now  be  regarded  as  a  well-established 
fact,3  and  it  is  one  which  ought  to  have  an  important  influence  on  our  dietetic 
arrangements.  For  if  the  total  withdrawal  of  these  articles  be  productive  of 
such  a  fearful  depravation  of  the  blood  as  perverts  every  function  to  which  the 
blood  is  subservient,  a  diminution  of  them  below  the  standard  requisite  for  the 
maintenance  of  health  must  necessarily  involve  a  depravation  similar  in  kind 

1  See  Dr.  Schleisner's  "Island  undersogt  fra  Isegevidenskabeligt  Synspunct,"  or  Report 
on  the  Sanitary  Condition  of  Iceland ;  and  the  analysis  of  it  in  the  "  Brit,  and  For.  Med.- 
Chir.  Rev.,"  vol.  v.  p.  456. 

2  For  a  full  inquiry  into  this  subject,  see  the  "Brit,  and  For.  Med.-Chir.  Rev.,"  vol.  ii. 
p.  439. 


NATURE   AND   DESTINATION    OF   FOOD.  383 

though  less  aggravated  in  degree ;  and  this,  if  slight,  may  be  expected  to  mani- 
fest itself,  not  so  much  in  the  production  of  idiopathic  disorders,  as  in  favoring 
any  peculiar  tendency  to  disease  which  may  exist  in  the  system,  and  in  prevent- 
ing or  retarding  recovery  from  its  effects.1  The  employment  of  fresh  fruits  and 
of  green  vegetables  seems  especially  indicated,  where  a  general  chronic  disorder 
of  nutrition  indicates  a  perverted  condition  of  the  circulating  material ;  and  espe- 
cially where  there  is  a  disposition  to  chronic  inflammation,  induration,  and  ulce- 
ration,  in  different  parts  of  the  body. 

v.  Finally,  then,  a  well-arranged  dietetic  scheme  ought  to  consist  of  such  a 
combination  of  the  Albuminous,  Oleaginous,  and  Farinaceous  constituents,  as  is 
most  appropriate  to  the  requirements  of  the  system; — a  larger  measure  of  the 
albuminous  being  supplied,  when  an  unusual  amount  of  nervo-muscular  exertion 
is  put  forth,  and  this  supply  being  then  most  advantageously  derived  from 
animal  flesh; — a  larger  measure  of  the  oleaginous  being  required  for  the  susten- 
tation  of  the  heat  in  a  frigid  atmosphere,  and  this  being  supplied  equally  well 
by  the  vegetable  kingdom  as  by  the  animal ; — and  a  larger  proportion  of  the 
farinaceous.,  as  a  substitute  for  the  oleaginous,  being  most  favorable  to  health 
under  a  high  atmospheric  temperature.  An  habitual  excess  in  the  use  of  either 
of  these  constituents,  above  what  the  demands  of  the  system  require,  tends 
towards  the  production  of  a  particular  "  diathesis"  or  constitutional  state,  which 
may  manifest  itself  in  a  great  variety  of  modes.  Thus,  an  excess  of  the  albu- 
minous components,  such  as  is  only  likely  to  occur  when  too  large  a  proportion 
of  animal  food  is  employed,  undoubtedly  favors  the  arthritic  diathesis,  which 
seems  to  consist  in  the  presence  of  imperfectly  assimilated  histogenetic  substances 
and  wrongly-metamorphosed  products  of  disintegration,  that  are  not  duly  elimi- 
nated in  the  kidneys;  and  this  diathesis  not  only  displays  itself  in  gout  and 
gravel,  but  modifies  the  course  of  other  diseases.  So,  again,  an  excess  of  the 
oleaginous  constituents  of  the1  food  tends  to  the  production  of  the  bilious  diathesis, 
in  which,  through  the  insufficient  elimination  cf  hydrocarbonaceous  matters,  the 
blood  becomes  charged  with  the  elements  of  bile.  The  excess  of  farinaceous 
matters,  moreover,  especially  when  combined  with  a  deficiency  of  the  albuminous 
(as  it  too  frequently  is  among  those  who  are  obliged  by  necessity  to  live  chiefly 
upon  a  upoor"  vegetable  diet),  tends  to  the  production  of  the  rheumatic  dia- 
thesis; which  seems  to  consist,  like  the  arthritic,  in  the  mal-assimilation  and 
wrong  metamorphosis  of  the  components  of  the  tissues,  but  to  lie  especially 
favored  by  the  presence  either  of  lactic  acid,  or  of  some  other  product  of  the 
metamorphosis  of  the  saccharine  compounds.  And,  as  already  pointed  out,  the 
deficiency  of  oleaginous  matters  seems  to  tend  to  the  development  of  the  scro- 
fulous diathesis;  and  that  of  fruits  and  fresh  vegetables  to  the  production  of  the 
scorbutic.* 

1  This  "  scorbutic  tendency"  was  fully  recognized  by  the  past  generation  of  physicians, 
who  practised  in  those  good  old  times  when  potatoes  were  a  luxury,  and  green  vegetables 
in  the  winter  almost  unknown,  when  the  middle  classes  fed  upon  salted  meat  during  a 
great  part  of  the  year,  and  when  sagacious  old  women  prescribed  nettle-tea  and  scurvy- 
grass,  with  a  course  of  lenitive  "spring-physic,"  for  the  "  cleansing  of  the  blood." 

2  It  is  worthy  of  remark  that,  in  the  times  when  even  the  wealthy  lived  during  four  or 
five  months  of  the  year  almost  exclusively  upon  meat,  bread,  and  flour-puddings,  and 
when,  therefore,  the  diet  was  far  too  highly  azotized,  as  well  as  deficient  in  fresh  vegetables, 
arthritic,  calculous,  and  scorbutic  disorders  were  much  more  common  than  at  present 
The  introduction  and  universal  employment  of  the  potato  has  unquestionably  done  much 
to  correct  these  two  tendencies ;  on  the  one  hand,  by  diluting  the  azotized  constituents 
of  the  food,  so  that,  with  the  same  bulk,  a  much  smaller  proportion  of  these  is  now  intro- 
duced ;  and  on  the  other,  by  supplying  to  the  blood  some  element  which  is  essential  to 
the  maintenance  of  its  healthy  condition.     But  with  the  diminution  of  the  arthritic  dia- 
thesis, which  the  experience  of  our  older  practitioners,  and  the- medical  writings  of  the 
last  century,  indicate  as  having  taken  place  during  that  period,  there  has  been  an  increase 
in  the  rheumatic  ; — a  change  which  seems  to  have  a  close  relation  to  this  alteration  in  diet 


384  OF    FOOD,    AND    THE   DIGESTI VE. PROCESS. 

405.  The  absolute  quantity  of  Food  required  for  the  maintenance  of  the  Human 
body  in  health,  varies  so  much  with  the  age,  sex,  constitution,  and  habits  of  the 
individual,  and  with  the  circumstances  in  which  he  may  be  placed,  that  it  would 
be  absurd  to  attempt  to  fix  any  standard  which  should  apply  to  every  particular 
case.     The  appetite  is  the  only  sure  guide  for  the  supply  of  the  wants  of  each ; 
but  its  indications  must  not  be  misinterpreted.     To  eat  when  we  are  hungry,  is 
an  evidently  natural  disposition;  but  to  eat  as  long  as  we  are  hungry,  may  not 
always  be  prudent.     Since  the  feeling  of  hunger  does  not  depend  so  much  upon 
the  state  of  fulness  or  emptiness  of  the  stomach,  as  upon  the  condition  of  the 
general  system,  it  appears  evident  that  the  ingestion  of  food  cannot  at  once  pro- 
duce the  effect  of  dissipating  it,  though  it  will  do  so  after  a  short  time  ;  so  that, 
if  we  eat  with  undue  rapidity,  we  may  continue  swallowing  food  long  after  we 
have  taken  as  much  as  will  really  be  required  for  the  wants  of  the  system ;  and 
every  superfluous  particle  is  not  merely  useless,  but  injurious.     Hence,  besides 
its  other  important  ends,  the  process  of  thorough  mastication  is  important,  as 
prolonging  the  meal,  and  giving  time  to  the  system  to  be  made  acquainted  (as 
it  were)  that  the  supply  of  its  wants  is  in  progress ;  so  that  its  demand  may  be 
abated  in  due  time  to  prevent  the  ingestion  of  more  than  is  required.    It  is  very 
justly  remarked  by  Dr.  Beaumont,  that  the  cessation  of  this  demand,  rather  than 
the  positive  sense  of  satiety,  is  the  proper  guide.     "  There  appears  to  be  a  sense 
of  perfect  intelligence  conveyed  to  the  encephalic  centre,  which  in  health  in- 
variably dictates  what  quantity  of  aliment  (responding  to  the  sense  of  hunger 
and  its  due  satisfaction)  is  naturally  required  for  the  purposes  of  life;  and  which, 
if  noticed  and  properly  attended  to,  would  prove  the  most  salutary  monitor  of 
health,  and  effectual  preventive  of  disease.     It  is  not  the  sense  of  satiety,  for 
this  is  beyond  the  point  of  healthful  indulgence,  and  is  Nature's  earliest  indica- 
tion of  an  abuse  and  overburden  of  her  powers  to  replenish  the  system.     It 
occurs  immediately  previous  to  this;  and  may  be  known  by  the  pleasurable  sen- 
sations of  perfect  satisfaction,  ease,  and  quiescence  of  body  and  mind.     It  is 
when  the  stomach  says,  enough;  and  it  is  distinguished  from  satiety  by  the 
difference  of  sensations — the  latter  saying  too  much."     Every  medical  man  is 
well  aware  how  generally  this  rule  is  transgressed;  some  persons  making  a  regu- 
lar practice  of  eating  to  repletion ;  and  others  paying  far  too  little  attention  to 
the  preliminary  operations,  and  thus  ingesting  more  than  is  good  for  them,  even 
though  they  .may  actually  leave  off  with  an  appetite. 

406.  Although  no  universal  law  can  be  laid  down  for  individuals,  however,  it 
is  a  matter  of  much  practical  importance  to  be  able  to  form  a  correct  average 
estimate.     It  is  from  the  experience  afforded  by  the  usual  consumption  of  food 
by  large  bodies  of  men,  that  our  data  are  obtained;  and  these  data  are  sufficient 
to  enable  us  to  predict  with  tolerable  accuracy  what  will  be  required  by  similar 
aggregations,  though  they  can  afford  no  guide  to  the  consumption  of  individuals. 
— We  shall  first  consider  the  quantity  sufficient  for  men  in  regular  active  exer- 
cise; and  then  inquire  how  far  that  may  be  safely  reduced  for  those  who  lead  a 
more  sedentary  life. — The  Diet-scale  of  the  British  Navy  may  be   advantage- 
ously taken  as  a  specimen  of  what  is  required  for  the  first  class.     It  is  well 
known  that  an  extraordinary  improvement  has  taken  place  in  the  health  of  sea- 

And  it  seems  not  improbable,  too,  that  this  alteration  in  diet  has  much  to  do  with  that 
diminished  power  of  sustaining  active  depletory  treatment,  which,  according  to  the  obser- 
vations of  practitioners  of  long  experience,  characterizes  the  present  generation  as  com- 
pared with  the  preceding.  But  whilst  there  is  a  diminished  capability  of  bearing  large 
bloodlettings,  violent  purgation,  &c.,  there  is  at  the  same  time  such  an  increased  tendency 
to  a  favorable  termination  in  many  of  those  diseases  for  which  they  were  formerly  ac- 
counted necessary,  as  should  remove  all  regret  at  this  change  of  constitution. — On  the 
question  of  "  Vegetarianism,"  the  Author  may  refer  to  his  articles  on  that  subject  in  the 
•«  Brit,  and  For.  Med.-Chir.  Rev.,"  vol.  vi.  pp.  76  and  399. 


NATURE   AND   DESTINATION   OP   FOOD.  385 

men  during  the  last  80  years;  so  that  three  ships  can  now  be  kept  afloat  with 
only  the  same  number  of  men  which  were  formerly  required  for  two.  This  is 
due  to  the  improvement  of  the  quality  of  the  food,  in  combination  with  other 
prophylactic  means.  At  present,  it  may  safely  be  affirmed  that  it  would  not  be 
easy  to  construct  a  diet-scale  more  adapted  to  answer  the  required  purpose.  The 
health  of  crews  that  have  been  long  afloat,  and  have  been  exposed  to  every  va- 
riety of  external  conditions,  appears  to  be  preserved  (at  least  when  they  are 
under  the  direction  of  judicious  officers)  to  the  full  as  well  as  that  of  persons 
subject  to  similar  vicissitudes  on  shore;  and  there  can  be  no  complaint  of  insuffi- 
ciency of  food,  although  the  allowance  cannot  be  regarded  as  superfluous.  It 
consists  of  from  31  to  35  i  ounces  of  dry  nutritious  matter  daily;  of  this  26  oz. 
are  vegetable,  and  the  rest  animal.  This  is  found  to  be  amply  sufficient  for  the 
support  of  strength ;  and  considerable  variety  is  produced  by  exchanging  various 
parts  of  the  diet  for  other  articles.  This,  however,  is  sometimes  done  errone- 
ously; thus  8  oz.  of  fresh  vegetables,  which  contain  only  \\  oz.  of  solid  nutri- 
ment, are  exchanged  for  12  oz.  of  flour,  which  is  almost  all  nutritious.  Sugar 
and  Cocoa  are  also  allowed,  partly  in  exchange  for  a  portion  of  the  Spirits 
formerly  served  out;  a  further  diminution  of  which  has  recently  been  effected, 
with  great  benefit. — A  considerable  reduction  in  this  amount  is  of  course  admis- 
sible, where  little  bodily  exertion  is  required,  and  where  there  is  less  exposure 
to  low  temperatures.  [The  diet-scale  of  the  United  States  Navy  is  even  more 
liberal  than  this;  it  is  as  follows:  Three  days  in  the  week — Pork,  16  oz. ;  beans 
or  peas,  7  oz. ;  biscuit,  14  oz. ;  pickles  or  cranberries,  1  oz. ;  sugar,  2  oz. ;  tea, 

1  oz. :— 40i  oz.      Two  days  in  the  week — Beef,  16  oz. ;  flour,  8  oz. ;  fruit  dried, 
4  oz. ;  biscuit,  14  oz. ;  tea  and  sugar,  2i  oz.;  pickles  or  cranberries,  1  oz. : — 45£ 
oz.      Two  days  in  the  week — Beef  16  oz.;  rice,  8  oz. ;  butter,  2  oz. ;  cheese, 

2  oz.;  biscuit,  14  oz.;  tea  and  sugar,  2i  oz.;  pickles  or  cranberries,  1  oz. : — 
45*  oz. 

The  judicious  admixture  of  the  vegetable  acids  with  the  other  articles  of  diet 
has  been  found  to  be  greatly  instrumental  in  warding  off  scurvy,  which  used  at 
one  time  to  be  so  greatly  dreaded  in  long  voyages.  By  diminishing  the  amount 
of  alkali  in  the  blood,  and  by  giving  non-nitrogenous  food,  the  scurvy  is  cured  or 
prevented,  in  consequence  of  such  substance  being  acted  on  instead  of  the  tissues 
of  the  body.  No  other  explanation  can  be  given  of  the  benefit  which  arises 
from  vegetable  acids,  from  fresh  vegetables,  from  sugar,  wine,  beer,  wort,  trea- 
cle, potatoes,  &c.,  all  of  which  have  been  used  with  the  best  effects.  See  Mr. 
Bence  Jones's  treatise  "  On  Gravel,  Calculus,  and  Gout/'  p.  48. 

The  importance  of  variety  of  food  need  scarcely  be  insisted  upon,  when  the 
number  of  principles  entering  into  the  composition  of  the  human  body  is  re- 
membered. The  living  body,  as  is  shown  by  Dr.  Pereira,1  has  no  power  of 
creating  elementary  substances;  it  is  obvious,  therefore,  that  the  system  must 
be  supplied  with  food  containing  all  the  elements  which  enter  into  its  composi- 
tion.— ED.] 

In  the  case  of  Prisoners,  the  diet  should  of  course  be  as  spare  as  possible, 
consistently  with  health;  but  it  should  be  carefully  modified,  in  individual 
cases,  according  to  several  collateral  circumstances,  such  as  depression  of  mind, 
compulsory  labor,  previous  intemperate  habits,  and  especially  the  length  of 
confinement.  It  has  been  supposed  by  some,  that  prisoners  require  a  fuller 
diet  than  persons  at  large;  this  is  probably  erroneous;  but  more  variety  is 
certainly  desirable,  to  counteract,  as  far  as  possible,  the  depressing  influence 
of  their  condition  upon  the  digestive  powers.  The  evil  effect  of  an  undue 
reduction  in  the  supply  of  food,  and  of  insufficient  attention  to  its  quality, 
has  unfortunately  been  too  frequently  displayed  in  our  prisons ;  a  notable  ex- 

1  On  Food  and  Diet. 
25 


386  OF   FOOD,    AND   THE   DIGESTIVE   PROCESS. 

ample  of  which  will  be  hereafter  alluded  to  (§  419).  A  very  excellent  scale  of 
dietaries  adapted  to  the  different  conditions  of  prison  life,  has  been  issued  by  the 
Government  on  the  recommendation  of  the  Inspector  of  Prisons. — The  effects  of 
confinement  have  been  well  shown  in  the  experience  of  the  Edinburgh  House  of 
Refuge,  which  was  first  established  in  1832,  for  the  reception  of  beggars  during 
the  Cholera,  and  which  has  been  continued  to  the  present  time.  The  diet  was 
at  first  a  quart  of  oatmeal  porridge  for  each  person,  morning  and  evening ;  and 
at  dinner  1  oz.  of  meat,  in  broth,  with  7  oz.  of  bread,  making  altogether  about 
23  oz.  of  solid  food  a  day.  During  some  months,  this  diet  seemed  to  answer 
very  well ;  the  people  went  out  fatter  than  they  came  in,  owing  to  the  diet  being 
better  than  that  to  which  they  had  been  accustomed;  but  afterwards  a  prone- 
ness  to  disease  manifested  itself  in  those  who  had  been  residents  there  for  a  con- 
siderable time,  and  the  diet  was  therefore  somewhat  increased,  with  good  effect. 
The  quantity  of  animal  food  was  probably  here  too  small;  and  the  total  weight 
might  still  have  been  sufficient,  if  it  had  been  differently  apportioned. — The 
inmates  of  Workhouses,  especially  those  who  have  been  accustomed  to  poor 
food  during  their  whole  lives,  require  much  less  than  those  more  actively  em- 
ployed ;  and  it  is  of  importance  that  the  diet  should  not  be  superior  in  quantity 
or  quality,  to  that  which  the  laboring  classes  in  the  respective  neighborhoods 
provide  for  themselves.  In  the  Edinburgh  workhouse,  of  which  the  inmates 
usually  have  good  health,  they  are  fed  upon  oatmeal  porridge  morning  and  even- 
ing, with  barley  broth  at  dinner ;  the  total  allowance  of  dry  nutriment  is  about 
17  oz.;  namely,  13  oz.  of  vegetable,  and  4  oz.  of  animal.  A  series  of  Diet-scales 
for  Paupers  has  been  issued  by  the  Poor-Law  Commissioners,  who  state  that 
these  have  all  been  employed  in  different  parts  of  England,  and  have  been  found 
to  work  well;  the  average  daily  amount  of  solid  aliment  in  these  is  only  25 £ 
oz. ;  and  of  this  not  above  18  oz.  would  be  dry  nutriment.1 

407.  The  smallest  quantity  of  food  upon  which  life  is  known  to  have  been 
supported  with  vigor,  during  a  prolonged  period,  is  that  on  which  Cornaro  states 
himself  to  have  subsisted.     This  was  no  more  than   12  oz.  a  day,  chiefly  of 
vegetable  matter,  with  14  oz.  of  light  wine,  for  a  period  of  58  years.     There  is 
only  one  instance  on  record,  in  which  his  plan  was  followed;  and  there  are 
probably  few  who  could  long  persevere  in  it,  at  least  among  those  whose  avoca- 
tions require  much  mental  or  bodily  exertion.     It  is  certain,  however,  that  life 
with  a  moderate  amount  of  vigor  may  be  preserved  for  some  time,  with  a  very 
limited  amount  of  food;  this  appears  from  the  records  of  shipwreck  and  similar 
disasters.     In  regard,  however,  to  those  who  have  been  stated  to  fast  for  a 
period  of  months  or  even  years,  taking  no  nutriment,  but  maintaining  an  active 
condition,  it  may  be  safely  asserted  that  they  were  impostors,  probably  possess- 
ing unusual  powers  of  abstinence,  which  they  took  care  to  magnify  (§  422). 

408.  Of  the  quantity  which  can  be  devoured  at  one  time,  this  is  scarcely  the 
place  to  speak;  since  such  feats  of  gluttony  only  demonstrate  the  extraordinary 
capacity  which  the  stomach  may  be  made  to  attain  by  continual  practice.    Many 
amusing  instances  are  related  by  Captain  Parry  in  his  Arctic  Voyages;  in  one 
case,  a  young  Esquimaux,  to  whom  he  had  given  (for  the  sake  of  curiosity)  his 
full  tether,  devoured  in  four-and-twenty  hours  no  less  than  35  Ibs.  of  various 
kinds  of  aliment,  including  tallow  candles.     A  case  has  more  recently  been 
published  of  a  Hindoo,  who  can  eat  a  whole  sheep  at  a  time;  this  probably 
surpasses  any  other  instance  on  record.     The  half-breed  voyageurs  of  Canada, 
according  to  Sir  John  Franklin,  and  the  wandering  Cossacks  of  Siberia,  as  testi- 
fied by  Capt.  Cochrane,  habitually  devour  a  quantity  of  animal  food,  which 
would  be  soon  fatal  to  any  one  unused  to  it.     The  former  are  spoken  of  as  very 

1  A  copious  collection  of  Dietaries  will  be  found  in  Dr.  Pereira's  "Treatise  on  Food  and 
Diet." 


NATURE   AND   DESTINATION   OP   FOOD.  387 

discontented,  when  put  on  a  short  allowance  of  8  Ibs.  of  meat  a  day;  their 
usual  consumption  being  from  12  to  20  Ibs. — That  a  much  larger  quantity  of 
food  than  that  formerly  specified,  may  be  habitually  taken  with  perfect  freedom 
from  injurious  consequences,  under  a  particular  system  of  exercise,  &c.,  appears 
from  the  experience  of  those  who  are  trained  for  feats  of  strength,  pugilistic 
encounters,  &c.  The  ordinary  belief  that  the  Athletic  constitution  cannot  be 
long  maintained,  appears  to  have  no  real  foundation;  nor  does  it  appear  that 
any  ultimate  injury  results  from  the  system  being  persevered  in  for  some  time. 
That  trained  men  often  fall  into  bad  health,  on  the  cessation  of  the  plan,  is 
probably  owing  in  part  to  the  intemperance  and  other  bad  habits  of  persons  of 
the  class  usually  subjected  to  this  discipline.  The  effects  of  trainers'  regimen 
are  hardness  and  firmness  of  the  muscles,  clearness  of  the  skin,  capability  of 
bearing  continued  severe  exercise,  and  a  feeling  of  freedom  and  lightness  (or 
"corkiness")  in  the  limbs.  During  the  continuance  of  the  system,  it  is  found 
that  the  body  recovers  with  wonderful  facility  from  the  effects  of  injuries; 
wounds  heal  very  rapidly;  cutaneous  eruptions  usually  disappear.  Clearness 
and  vigor  of  mind,  also,  are  stated  to  be  results  of  this  plan.1 

409.  It  is  not  enough  for  the  healthy  support  of  the  body,  that  the  Food  in- 
gested should  contain  an  adequate  proportion  of  alimentary  constituents;  it  is 
important  that  these  should  be  in  a  wholesome  or  undecomposing  state.  Put- 
ting out  of  view  all  impregnations  with  deleterious  substances,  which  the  articles 
used  as  food  may  have  received  from  various  external  sources,  it  cannot  be 
questioned  that  they  may  derive  a  poisonous  character  from  changes  taking  place 
in  their  own  nature  and  composition.  Thus  it  is  a  fact  very  familiar  to  German 
Toxicologists,  that  cheese,  bacon,  sausages,  and  other  articles,  may  spontaneously 
undergo  such  deleterious  alterations,  as  give  rise,  when  they  are  employed  as 
food,  to  all  the  symptoms  of  irritant  poisoning,  which  may  even  pass  on  to  pro- 
duce fatal  consequences;  that  such  occurrences  are  very  rare  in  this  country,  is 
probably  to  be  attributed  to  a  difference  in  the  mode  of  preparation.  This 
change  does  not  appear  to  consist  in  simple  putrescence;  for  the  effects  which 
the  cheese-poison,  sausage-poison,  &c.,  produce  on  the  animal  economy,  are  far 
more  potent  than  mere  putrescence  could  occasion ;  and  it  is  supposed  by  Liebig 
to  consist  in  the  generation  of  a  peculiar  ferment,  which  the  stomach  is  not  able 
to  decompose.  Similar  changes  in  ordinary  flesh-meat  seem  to  be  sometimes 
consequent  upon  the  previous  existence  of  a  diseased  condition  in  the  animal 
which  furnished  it.  Many  instances  of  this  kind  have  been  recorded  ;2  and 
the  risk  is  quite  sufficient  to  justify  a  strict  prohibition  of  the  use  of  any  such 
article. — That  meat  which  is  simply  putrescent  is  to  be  considered  as  injurious 
per  se,  when  habitually  employed,  is  scarcely  a  matter  of  reasonable  doubt.  It 
is  true  that  some  nations  are  in  the  habit  of  keeping  their  meat  until  it  is  tainted, 
having  a  preference  for  it  in  that  condition,  which  seems  to  have  grown  out  of 
the  supposed  necessity  for  thus  employing  it  (a  preference  which  has  its  parallel 

1  The  method  of  training  employed  by  Jackson  (a  celebrated  trainer  of  prize-fighters  in 
modern  times),  as  deduced  from  his  answers  to  questions  put  to  him  by  John  Bell,  was  to 
begin  on  a  clear  foundation,  by  an  emetic  and  two  or  three  purges.     Beef  and  mutton,  the 
lean  of  fat  meat  being  preferred,  constituted  the  principal  food ;  veal,  lamb,  and  pork  were 
said  to  be  less  digestible  ("the  last  purges  some  men").     Fish  was  said  to  be  a  "watery 
kind  of  diet :"  and  is  employed  by  jockeys  who  wish  to  reduce  weight  by  sweating.     Stale 
bread  was  the  only  vegetable  food  allowed.     The  quantity  of  fluid  permitted  was  3  J  pints 
per  diem ;  but  fermented  liquors  were  strictly  forbidden.     Two  full  meals,  with  a  light 
supper,  were  usually  taken.     The  quantity  of  exercise  employed  was  very  considerable, 
and  such  as  few  men  of  ordinary  strength  could  endure.     This  account  corresponds  very 
much  with  that  which  Hunter  gave  of  the  North  American  Indians,  when  about  to  set  out 
on  a  long  march. 

2  See  "Ann.  d'Hygiene,"  1829,  ii.  p.  267  ;  1834,  ii.  69 ;  also  Taylor  in  «  Guy's  Hospital 
Reports,"  April,  1843. 


885  OF   FOOD,   AND   THE   DIGESTIVE   PROCESS. 

among  the  epicures  in  our  own  country,  who  consider  the  haut  gotit  essential  to 
the  perfection  of  their  venison  or  woodcock).  One  of  the  most  remarkable  ex- 
amples of  this  kind  among  a  civilized  people  is  furnished  by  the  inhabitants  of 
the  Faroe  islands;  who,  according  to  the  Report  of  Dr.  Panum,  who  has  in- 
vestigated their  Sanitary  condition,  live  during  a  large  part  of  the  year  upon 
meat  in  a  state  of  incipient  decomposition,  and  introduce  rast,  or  half-decayed 
maggoty  flesh,  fowl,  or  fish,  as  a  special  relish  at  the  end  of  a  meal.1  The  re- 
sult of  such  a  diet  is  (as  might  be  anticipated)  a  continual  disorder  of  the  diges- 
tive organs,  manifesting  itself  especially  by  diarrhoea.  This  is  a  symptom  of 
annual  occurrence  on  the  bird-islands,  and  is  also  invariably  observed  after  a 
large  "take"  of  whales,  when  much  of  the  flesh  of  these  animals  necessarily 
becomes  "rast"  before  it  is  consumed.  And  this  diarrhoea  also  complicates  the 
course  of  other  diseases,  and  even  becomes,  from  its  obstinacy  and  exhausting 
character,  their  most  serious  occurrence.  Moreover,  the  Faroese  are  peculiarly 
liable  to  suffer  severely  from  epidemics,  when  these  are  introduced  among  them; 
as  was  especially  shown  in  the  epidemic  of  Measles  investigated  by  Dr.  Panum, 
which  attacked  in  the  course  of  six  months  scarcely  less  than  6000  out  of  a 
population  of  7782,  no  age  being  spared,  and  very  few  escaping,  save  such  as 
had  suffered  from  the  malady  in  the  epidemic  which  had  occurred  65  years  pre- 
viously, and  such  as  maintained  a  very  rigorous  isolation.  Hence,  notwithstand- 
ing that  the  usual  rate  of  mortality  is  very  low  (only  1  in  64f  annually),  it  is 
obvious  that  there  is  a  certain  constitutional  condition  among  them,  which  pecu- 
liarly favors  the  reception  and  propagation  of  Zymotic  poisons;  and  it  is  quite 
conformable  to  the  principles  formerly  laid  down  (§  210),  to  attribute  this  to 
the  habitual  introduction  of  putrescent  matter  with  the  food.  It  is  probable, 
indeed,  that  if  it  were  not  for  the  active  lives  of  the  Faroese,  and  their  habitual 
exposure  to  a  low  external  temperature,  the  direct  effects  of  their  diet  would  be 
far  more  prejudicial  than  they  are;  but  a  large  part  of  these  are  probably  neu- 
tralized by  that  activity  of  respiration  which  the  habits  of.  life  of  this  hardy 
people  induce,  much  of  the  noxious  matter  being  decomposed  and  eliminated  by 
the  combustive  process  (§  208).  Hence  it  may  well  be  conceived,  that  the  effects 
of  putrescent  food  would  be  much  more  decidedly  manifested  amongst  individuals 
habitually  living  in  close  ill- ventilated  apartments;  and  although  the  same 
means  of  comparison  do  not  exist,  since  there  is  ho  part  of  our  town-population 
habitually  subsisting  on  such  a  diet  as  that  of  the  Faroese,  yet  there  is  no  want 
of  evidence  with  regard  to  the  injurious  effects  of  even  the  occasional  employ- 
ment of  putrescent  food,  especially  when  any  zymotic  disease  is  epidemic.3 

1  See  Dr.  Panum's  "Observations  on  an  Epidemic  of  Measles  in  the  Faroe  Islands,"  in 
the  "Bibliothek  for  Laegr.,"  1846;  of  which  an  analysis  is  given  in  the  "Brit,  and  For. 
Med.-Chir.  Rev.,"  vol.  vii.  p.  419. — Dr.  Panum  says,  "During  the  interval  of  many  months 
that  the  flesh,  fish,  or  fowl,  is  neither  fresh,  nor  yet  wind-dried,  it  is  called  'rast,'  a  word 
which  I  can  only  translate  by  half-rotten.     This  appellation  it  fully  deserves  from  the  hor- 
rible smell  that  it  sends  forth,  from  its  mouldy  aspect,  and  the  numerous  maggots  that 
swarm  upon  it.     I  have  seen  a  boat's  crew  of  eight  men  eating  with  great  relish  the 
raw  flesh  of  the  ca'aing  whale,  even  though  it  was  so  decomposed  that  the  smell  of  it  was 
disagreeable  to  me  even  in  an  open  boat,  and  the  bottom  of  the  boat  was  almost  white  with 
the  maggots  that  fell  from  the  decaying  mass." 

2  Facts  of  this  kind  were  abundantly  furnished  during  the  last  visitation  of  Cholera. 
See  the  "Report  of  the  General  Board  of  Health  on  the  Epidemic  Cholera  of  1848  and 
1849,"  pp.  63, 64. — An  instance  of  a  very  remarkable  kind  occurred  at  Bridgewater,  towards 
the  close  of  the  epidemic,  as  related  to  the'  Author  by  Dr.  Brittan.     A  cargo  of  spoiled 
oysters  having  been  brought  to  the  town,  and  the  sale  of  them  having  been  prohibited  on 
account  of  their  putrescent  condition,  they  were  given  away  to  any  who  would  receive 
them;  and  several  children  in  a  neighboring  school  partook  of  them  plentifully.     In  the 
course  of  the  following  night,  all  who  had  eaten  of  the  oysters  (so  fur  as  Dr.  Brittau  could 
ascertain)  were  attacked  with  cholera  and  choleraic  diarrhoea,  and  eleven  of  the  children 
died  the  next  day. 


NATURE   AND  DESTINATION   OF   FOOD.  389 

410.  That  it  is  "Water  which  constitutes  the  natural  drink  of  Man,  and  that 
no  other  liquid  can  supply  its  place,  is  apparent  from  what  has  been  already  said 
of  its  uses  in  the  system  (§§  74,  75);  and  it  is  only  necessary  here  to  remark,  that 
the  purity  of  the  water  habitually  ingested  is  a  point  of  extreme  importance. 
A  very  minute  impregnation  with  lead,  for  example,  is  quite  sufficient  to  deve- 
lop all  the  symptoms  of  chronic  lead-poisoning,  if  the  use  of  such  water  be 
sufficiently  prolonged.     In  the  case  formerly  referred  to  (§  89),  the  amount  of 
lead  was  only  about  1  grain  per  gallon;  and  in  a  case  subsequently  published, 
in  which  also  the  symptoms  of  lead-poisoning  were  unequivocally  developed,  the 
amount  was  no  more  than  l-9th  of  a  grain.1     So  again,  an  excess  of  the  saline 
ingredients  which  appear  to  be  innocuous  in  small  quantities,  may  produce  a 
marked  disorder  of  the  digestive  organs,  and  (through  them)  of  the  system  gene- 
rally.3    Moreover,  as  in  the  case  of  food,  the  presence  of  a  very  small  amount 
of  putrescent  matter  is  quite  sufficient  to  produce  the  most  pernicious  results, 
when  that  matter  is  habitually  introduced  into  the  system ;  and  these  results,  on 
the  one  hand,  manifest  themselves  in  the  production  of  certain  disorders  which 
appear  distinctly  traceable  to  the  direct  action  of  the  poison  so  introduced ;  whilst, 
on  the  other,  they  become  apparent  in  the  extraordinary  augmentation  of  the 
liability  to  attacks  of  such  zymotic  diseases  as  may  at  the  time  be  prevalent.3 

411.  The  various  beverages  employed  by  Man  for  the  most  part  consist  of 
Water  holding  solid  matters  of  different  kinds  in  solution ;  and  it  is  not  requisite, 
therefore,  to  bestow  any  special  attention  upon  them.     But  the  use  of  Alcohol, 
in  combination  with  water    and  with  organic  and   saline  compounds,  in   the 
various  forms 'of  "  fermented  liquors,"  deserves  particular  notice,  on  account  of 
the  numerous  fallacies  which  are  in  vogue  respecting  it. — In  the  first  place  it  may 
be  safely  affirmed,  that  Alcohol  cannot  answer  any  one  of  those  important  pur- 
poses for  which  the  use  of  Water  is  required  in  the  system;   and  that,  on  the 
other  hand,  it  tends  to  antagonize  many  of  those  purposes,  by  its  power  of  pre- 
cipitating most  of  the  organic  compounds,  whose  solution  in  water  is  essential 
to  their  appropriation  by  the  living  body.     Secondly,  the  ingestion  of  Alcoholic 
liquors  cannot  supply  anything  which  is  essential  to  the  due  nutrition  of  the 
system ;  since  we  find  not  only  individuals,  but  whole  nations,  maintaining  the 
highest  vigor  and  activity,  both  of  body  and  mind,  without  ever  employing  them 
as  an  article  of  diet.      Thirdly,  there  is  no  reason  to  believe  that  Alcohol,  in 
any  of  its  forms,  can  become  directly  subservient  to  the  Nutrition  of  the  tissues; 
for  it  may  be  certainly  affirmed  that,  in  common  with  non-azotized  substances 
in  general,  it  is  incapable  of  transformation  into  Albuminous  compounds;  and 
there  is  no  sufficient  evidence  that  even  Fatty  matters  can  be  generated  in  the 

1  See  "Medical  Gazette,"  Sept.  20,  1850,  p.  518. 

2  Of  this  a  very  instructive  case,  which  occurred  at  Wolverton,  has  been  published  by 
Mr.  Corfe  in  the  "  Pharmaceutical  Journal,"  July,  1848.    So  large  a  number  of  individuals 
were  there  attacked,  after  the  use  of  water  from  a  certain  well  for  some  months,  with  dis- 
orders bearing  a  strong  general  resemblance  to  each  other,  though  differing  in  their  subor- 
dinate features,  and  the  intensity  of  these  disorders  bore  such  a  constant  ratio  to  the  amount 
of  the  saline  waters  habitually  employed,  that  no  reasonable  doubt  could  exist  with  respect 
to  its  causative  agency.     Yet  the  total  quantity  of  saline  matter  was  only  about  40  grains 
per  gallon,  or  but  little  more  than  one-sixth  of  that  which  is  contained  in  the  Marienbad 
water,  the  spa  to  which  it  presented  the  greatest  resemblance  in  the  combination  of  its 
components ;  and  as  the  symptoms  which  were  prevalent  at  Wolverton  bore  a  very  close 
correspondence  with  those  which  are  known  to  result  from  the  imprudent  use  of  the 
Marienbad  water,  it  appears  that  here  too  the  same  effects  are  produced  by  the  long- 
continued  employment  of  the  weaker  beverage,  as  by  a  much  smaller  number  of  doses  of 
the  stronger  one. 

3  For  ample  evidence  to  this  effect,  see  Dr.  Pereira's  "Treatise  on  Food  and  Diet,"  pp. 
89-91 ;  and  the  "  Report  of  the  General  Board  of  Health  on  the  Epidemic  Cholera  of  1848 
and  1849,"  pp.  59-63,  "Appendix  A,"  p.  14,  and  "Appendix  B,"  pp.  91-95. 


390  OF   FOOD,    AND   THE   DIGESTIVE   PROCESS. 

body  at  its  expense.1  Fourthly,  the  alimentary  value  of  Alcohol  consists  merely 
in  its  power  of  contributing  to  the  production  of  Heat,  by  aifording  a  pabulum 
for  the  respiratory  process ;  but  for  this  purpose  it  would  be  pronounced  on 
Chemical  grounds  alone  to  be  inferior  to  fat  (§  401);  and  the  result  of  the  ex- 
perience of  Arctic  voyagers  and  travellers  is  most  decided  in  regard  to  the  low 
value  of  Alcohol  as  a  heat-producing  material. — Fifthly,  the  operation  of  Alcohol 
upon  the  living  body  is  essentially  that  of  a  stimulus;  increasing  for  a  time, 
like  other  stimuli,  the  vital  activity  of  the  body,  and  especially  that  of  the  nervo- 
muscular  apparatus,  so  that  a  greater  effect  may  often  be  produced  in  a  given 
time  under  its  use,  than  can  be  obtained  without  it  ;  but  being  followed  by  a 
corresponding  depression  of  power,  which  is  the  more  prolonged  and  severe  in 
proportion  as  the  previous  excitement  has  been  greater.  Nothing,  therefore,  is 
in  the  end  gained  by  their  use ;  which  is  only  justifiable  where  some  temporary 
emergency  can  only  be  met  by  a  temporary  augmentation  of  power,  even  at  the 
expense  of  an  increased  amount  of  subsequent  depression;  or  where  (as  in  the 
case  of  some  individuals  whose  digestive  power  is  deficient)  it  affords  aid  in  the 
introduction  of  aliment  into  the  system,  which  nothing  else  can  so  well  supply. 
These  cases,  however,  will  be  less  numerous,  in  proportion  as  due  attention  is 
paid  to  other  means  of  promoting  health,  which  are  more  in  accordance  with 
Nature. — The  Physiological  objections  to  the  habitual  use  of  even  small  quanti- 
ties of  Alcoholic  liquors  rest  upon  the  following  grounds :  First,  they  are  uni- 
versally admitted  to  possess  a  poisonous  character,  when  administered  in  large 
doses ;  death  being  the  speedy  result,  through  the  suspension  of  nervous  power 
which  their  introduction  into  the  circulation,  in  sufficient  quantity,  is  certain  to 
induce. — Secondly,  when  habitually  used  in  excessive  quantities,  universal  ex- 
perience shows  that  Alcoholic  liquors  tend  to  produce  a  morbid  condition  of  the 
body  at  large,  and  especially  of  the  nervous  system ;  this  condition  being  such 
as  a  knowledge  of  its  modus  operandi  on  the  body  would  lead  the  Physiologist 
to  predicate. —  Thirdly,  the  frequent  occurrence  of  more  chronic  diseases  of  the 
same  character  among  persons  advanced  in  life  who  have  habitually  made  use 
of  Alcoholic  liquors  in  "  moderate"  amount,  affords  a  strong  probability  that  they 
result  from  a  gradual  perversion  of  the  nutritive  processes,  of  which  that  habit 
is  the  cause. — Fourthly,  the  special  liability  of  the  intemperate  to  zymotic  dis- 
eases indicates  that  the  habitual  ingestion  of  alcoholic  liquors  tends  to  prevent 
the  due  elimination  of  the  products  of  the  disintegration  of  the  system,  and  thus 
to  induce  a  "  fermentible"  condition  of  the  blood  (§  210).  Fifthly,  extended 
experience  has  shown  that,  notwithstanding  the  temporary  augmentation  of  power 
which  may  result  from  the  occasional  use  of  fermented  liquors,  the  capacity  for 
prolonged  endurance  of  mental  or  bodily  labor,  and  for  resisting  the  extremes -of 
heat  and  cold,  as  well  as  other  depressing  agencies,  is  diminished  rather  than 
increased  by  their  habitual  employment. — On  these  grounds,  the  Author  has 
felt  himself  fully  justified  in  the  conclusion,  that,  for  Physiological  reasons 
alone,  habitual  abstinence  from  Alcoholic  liquors  is  the  best  rule  that  can  be 
laid  down  for  the  great  majority  of  healthy  individuals;  the  exceptional  cases  in 
which  any  real  benefit  can  be  derived  from  their  use,  being  extremely  few.3 

1  It  is  quite  true  that  some  persons  who  consume  large  quantities  of  fermented  liquors 
become  very  fat ;  but  the  material  for  this  fat  is  probably  derived  in  part  from  the  consti- 
tuents of  the  food,  and  in  part  from  the  disintegration  of  the  tissues ;  the  hydrocarbonaceous 
matters  in  the  system  being  prevented  from  undergoing  the  combustive  process  to  which 
they  would  otherwise  be  subject,  by  the  superior  affinity  for  oxygen  which  Alcohol  pos- 
sesses.    Much  of  the  fatty  deposit  in  intemperate  persons  has  the  character  of  "fatty 
degeneration;"  the  tendency  to  which  is  very  marked  in  persons  of  this  class. 

2  See  his  Prize  Essay  "On  the  Use  and  Abuse  of  Alcoholic  Liquors  in  Health  and  Dis- 
ease," Am.  Ed. ;  also  the  important  Treatise  on  "  Alcoholiemus  Chronicus,"  by  Dr.  Huss  of 
Stockholm,  of  which  an  abstract  is  given  in  the  "Brit,  and  For.  Med.-Chir.  Rev.,"  vols. 
vii.  and  ix. 


OF   HUNGER  AND   THIRST.  —  STARVATION.  391 


2.    Of  Hunger  and  Thirst; — Starvation. 

412.  The  want  of  solid  aliment,  arising  out  of  the  several  sources  of  demand 
formerly  enumerated  (§§  374-6),  is  indicated  by  the  sensation  of  Hunger;  and 
that  of  liquid  by  Thirst.     The  former  of  these  sensations  is  referred  to  the  sto- 
mach, and  the  latter  to  the  fauces;  but  although  certain  conditions  of  these 
parts  may  be  the  immediate  cause  of  the  sensations  in  question,  they  are  really 
indicative  of  the  requirements  of  the  system  at  large.     For  the  intensity  of  the 
feelings  bears  no  constant  relation  to  the  amount  of  solid  or  liquid  aliment  in 
the  stomach ;  whilst,  on  the  other  hand,  it  does  correspond  with  the  excess  of 
demand  in  the  system,  over  the  supply  afforded  by  the  blood ;  and  it  is  caused 
to  abate  by  the  introduction  of  the  requisite  materials  into  the  circulating  fluid, 
even  though  this  be  not  accomplished  in  the  usual  manner  by  the  ingestion  of 
food  or  drink  into  the  stomach. 

413.  That  the  sense  of  Hunger,  however,  is  immediately  dependent  upon 
some  condition  of  the  Stomach,  seems  to  follow  from  the  fact  that  it  may  be 
temporarily  alleviated  by  introducing  into  the  digestive  cavity  matter  which  is 
not  alimentary.     Of  the  precise  nature  of  that  condition,  however,  we  have  no 
certain  knowledge.     It  is  easy  to  prove  that  many  of  the  causes  which  have 
been  assigned  for  the  sensation,  are  but  little,  if  at  all,  concerned  in  producing 
it.     Thus,  mere  emptiness  of  the  Stomach  cannot  occasion  it;  since,  if  the  pre- 
vious meal  have  been  ample,  the  food  passes  from  its  cavity  some  time  before 
the  uneasy  feeling  is  renewed ;  and  this  emptiness  may  continue  (in  certain  dis- 
ordered states  of  the  system)  for  many  hours  or  even  days,  without  a  return  of 
desire  for  food.     Besides,  the  stomach  may  be  filled  with  food,  and  yet  Hunger 
may  be  intensely  felt,  if,  from  disease  of  the  pylorus  or  any  other  cause,  there 
be  an  obstacle  to  the  passage  of  the  aliment  into  the  intestine,  and  to  the  com- 
pletion of  the  processes  of  chylification  and  absorption,  so  that  the  system  needs 
that  which  the  digestive  apparatus  is  unable  to  provide  for  it.     Again,  the  sense 
of  Hunger  cannot  be  due,  a&  some  have  supposed,  to  the  action  of  the  gastric 
fluid  upon  the  coats  of  the  stomach  themselves;  since  this  fluid  is  not  poured 
into  the  stomach,  except  when  the  production  of  it  is  stimulated  by  the  irrita- 
tion of  its  secreting  follicles.     It  is  thought  by  Dr.  Beaumont  that  the  disten- 
sion of  these  follicles  with  the  secreted  fluid  is  the  proximate  cause  of  hunger; 
but  there  is  no  more  reason  to  believe,  that  the  secretion  of  gastric  fluid  is  accu- 
mulating during  the  intervals  when  it  is  not  required,  than  there  is  in  regard  to 
saliva,  the  lachrymal  fluid,  or  any  other  secretions,  which  are  occasionally  poured 
out  in  large  quantities  under  the  influence  of  a  particular  stimulus;  and,  more- 
over, it  is  difficult  to  imagine  how  mental  emotion,  or  any  impression  on  the 
nervous  system  alone  (which  is  able,  as  is  well  known,  to  dissipate  the  keenest 
appetite  in  'a  moment),  can  relieve  such  distension. — It  may,  perhaps,  be  a  more 
probable  supposition,  that  there  is  a  certain  condition  of  the  Capillary  circula- 
tion in  the  Stomach,  which  is  preparatory  to  the  secretion,  and  which  is  excited 
by  the  influence  of  the  Sympathetic  nerves,  that  communicate  (as  it  were)  the 
wants  of  the  general  system.     This  condition  may  be  easily  imagined  to  be  the 
proximate  cause  of  the  sensation  of  hunger,  by  acting  on  the  nervous  centres.1 

1  It  was  maintained  by  Brachet,  that  the  senses  of  Hunger  and  Satiety  are  annihilated 
by  section  of  the  Pneumogastric  nerves ;  which,  if  true,  would  strongly  confirm  the  view 
that  the  immediate  source  of  these  senses  lies  in  the  condition  of  the  Stomach.  But  the 
researches  of  other  experimenters,  particularly  those  of  Dr.  John  Reid  ("  Edinb.  Med.  and 
Surg.  Journ.,"  April,  1839,  and  "Physiological,  Anatomical,  and  Pathological  Researches," 
pp.  234-239),  do  not  confirm  this  view ;  for  they  seem  to  show  that  after  the  immediate 
eifect  of  the  operation  has  subsided,  animals  take  food  with  no  less  avidity  than  previously. 
It  appears,  however,  from  Dr.  Reid's  observations,  'as  well  as  from  those  of  Valentin,  that 


392  OP   FOOD,   AND   THE   DIGESTIVE   PROCESS. 

When  food  is  introduced  into  the  stomach,  the  act  of  secretion  is  directly  ex- 
cited; the  capillary  vessels  are  gradually  unloaded;  and  the  immediate  cause  of 
the  impression  on  the  nervous  system  is  withdrawn.1  By  the  conversion  of  the 
alimentary  matter  into  materials  fit  for  the  nutrition  of  the  system,  the  remote 
demand  also  is  satisfied;  and  thus  it  is  that  the  condition  of  the  stomach,  just 
referred  to,  is  permanently  relieved  by  the  ingestion  of  substances  that  can 
serve  as  food.  But  if  the  ingested  matter  be  not  of  a  kind  capable  of  solution 
and  assimilation,  or  the  digestive  apparatus  cannot  effect  its  preparation,  the 
feeling  of  hunger  is  only  temporarily  relieved,  and  soon  returns  in  greater  force 
than  before. — The  theory  here  given  seems  reconcilable  with  all  that  has  been 
said  of  the  conditions  of  the  sense  of  Hunger ;  and  particularly  with  what  is 
known  of  the  effect  produced  upon  it  by  nervous  impressions,  which  have  a  pecu- 
liar influence  upon  the  capillary  circulation.  It  also  corresponds  exactly  with 
what  we  know  of  the  influence  of  the  nervous  system,  and  of  mental  impressions, 
upon  other  secretions  (CHAP.  xiv.  SECT.  6). 

414.  The  sense  of  Hunger,  like  other  sensations,  may  not  be  taken  cogni- 
zance of  by  the  Mind,  if  its  attention  be  strongly  directed  towards  other  objects; 
of  this  fact,  almost  every  one  engaged  in  active  occupations,  whether  mental  or 
bodily,  is  occasionally  conscious.     The  nocturnal  student,  who  takes  a  light  and 
early  evening  meal,  and,  after  devoting  himself  to  his  pursuits  for  several  hours 
uninterruptedly,  retires  to  rest  with  a  wearied  head  and  an  empty  stomach,  but 
without  the  least  sensation  of  hunger,  is  frequently  prevented  from  sleeping  by 
an  indescribable  feeling  of  restlessness  and  deficiency,  and  the  introduction  of 
a  small  quantity  of  food  into  the  stomach  will  almost  instantaneously  allay  this, 
and  procure  comfortable  rest.     Many  persons,  again,  who  desire  to  take  active 
exercise  before  breakfast,  are  prevented  from  doing  so  by  the  lassitude  and  even 
faintness  which  it  induces,  the  bodily  exercise  increasing  the  demand  for  food, 
whilst  it  draws  off  the  attention  from  the  sensation  of  hunger.2 

415.  The  conditions  of  the  sense  of  Thirst  appear  to  be  very  analogous  to 

the  sense  of  Satiety  is  more  dependent  upon  the  continuity  of  these  nerves  than  that  of 
Hunger ;  for  animals  on  whom  the  section  of  the  Pneumogastric  has  been  performed,  do 
not  seem  to  know  when  they  have  had  enough,  but  continue  to  gorge  themselves  with  food 
long  after  the  stomach  has  been  adequately  filled. 

1  These  views  are  confirmed  by  the  observations  of  M.  Bernard  on  the  condition  of  the 
gastric  follicles  during  the  intervals  of  their  functional  activity.    He  states  that  when  the 
stomach  is  empty,  the  follicles  are  lined  by  cylindrical  epithelium  of  the  same  kind  as  that 
which  covers  the  general  surface  of  the  gastric  mucous  membrane ;  and  this  even  blocks  up 
their  orifices,  so  that  during  fasting  these  appear  as  minute  slightly  prominent  papillae. 
The  gastric  fluid  is  contained  in  newly-formed  cells  which  are  rapidly  generated  and  thrown 
off,  when  the  secreting  process  is  called  into  renewed  activity.   ("Gaz.  Med.,"  Mars,  1844.) 

2  The  Author  may  be  excused  from  mentioning  the  following  circumstance,  which  some 
years  ago  occurred  to  himself,  and  which  seems  to  him  a  good  illustration  of  the  principle 
that  the  sense  of  hunger  originates  in  the  condition  of  the  general  system,  and  that  its 
manifestation  through  a  peculiar  action  in  the  stomach,  is  to  be  regarded  as  a  secondary 
phenomenon — adapted,  under  ordinary  circumstances,  to  arouse  the  mind  to  the  actions 
necessary  for  the  supply  of  the  physical  wants — but  capable  of  being  overlooked,  if  the 
attention  of  the  mind  be  otherwise  directed.     He  was  walking  alone  through  a  beautiful 
country,  and  with  much  to  occupy  his  mind ;  and,  having  expected  to  meet  with  some 
opportunity  of  obtaining  refreshment  on  his  road,  he  had  taken  no  food  since  his  breakfast. 
This  expectation,  however,  was  not  fulfilled ;  but,  as  he  felt  no  hunger,  he  thought  little 
of  the  disappointment.     It  was  evening  before  he  approached  the  place  of  his  destination, 
after  having  walked  about  twenty  miles,  resting  frequently  by  the  way  ;  and  he  then  began 
to  feel  a  peculiar  lassitude,  different  from  ordinary  fatigue,  which  rapidly  increased,  so  that 
during  the  last  mile  he  could  scarcely  support  himself. — The   "stimulus  of  necessity," 
however,  kept  him  up  ;  but  on  arriving  at  his  temporary  home,  he  immediately  fainted. 
It  is  obvious  that,  in  this  case,  the  occupation  of  the  mind  on  the  objects  around,  and  on 
its  own  thoughts,  had  prevented  the  usual  warning  of  hunger  from  being  perceived ;  and 
the  effect  which  succeeded  was  exactly  what  was  to  be  anticipated,  from  the  exhaustion  of 
the  supply  of  food  occasioned  by  the  active  and  prolonged  exertion. 


OF   HUNGER  AND   THIRST.  —  STARVATION.  393 

those  of  hunger.  This  sense  is  not  referred,  however,  to  the  stomach,  but  to 
the  fauces.  It  is  generally  considered  that  it  immediately  results  from  an  im- 
pression on  the  nerves  of  the  stomach ;  since,  if  liquids  are  introduced  into  the 
stomach  through  an  oesophagus-tube,  they  are  just  as  effectual  in  allaying  thirst, 
as  they  are  if  swallowed  in  the  ordinary  manner.  It  may,  however,  be  doubted 
whether  the  sense  of  thirst  is  not  even  more  immediately  connected  with  the 
state  of  the  general  system,  than  that  of  hunger;  for  the  immediate  relief 
afforded  by  the  introduction  of  liquid  into  the  stomach  is  fully  accounted  for, 
by  the  instantaneous  absorption  of  the  fluid  into  the  veins,  which  is  known  to 
take  place,  when  there  is  a  demand  for  it,  not  only  from  Dr.  Beaumont's  obser- 
vations, but  from  many  experiments  made  with  reference  to  this  particular 
question.  This  demand  is  increased  with  almost  equal  rapidity,  by  an  excess 
in  the  amount  of  the  fluid  excretions;  and  it  may  be  satisfied,  or  at  least  alle- 
viated, without  the  introduction  of  water  into  the  stomach,  this  having  been 
one  of  the  results  observed  after  the  use  of  saline  injections  into  the  veins  in 
cases  of  Asiatic  Cholera,  as  well  as  after  the  immersion  in  a  warm  bath  in  cases 
of  extreme  dysphagia.  Thirst  may  also  be  produced,  however,  by  the  impres- 
sion made  by  peculiar  kinds  of  food  or  drink  upon  the  walls  of  the  alimentary 
canal;  thus,  salted  or  highly-spiced  meat,  fermented  liquors  when  too  little 
diluted,  and  other  similarly  irritating  agents,  excite  thirst;  the  purpose  of  which 
is  obviously  to  cause  ingestion  of  fluid,  by  which  they  may  be  diluted. 

416.  The  results  of  an  entire  deficiency  of  Food,  or  of  its  supply  in  a  measure 
inadequate  for  the  wants  of  the  system,  constitute  the  phenomena  of  Inanition 
or  Starvation.  These  have  been  experimentally  studied  by  M.  Chossat1  on 
Birds  and  Mammals ;  and  the  information  thence  gained  leads  us  to  a  better 
comprehension  of  what  is  (unfortunately)  too  frequently  exhibited  in  the  Human 
subject. — The  following  were  the  general  symptoms  noted  by  M.  Chossat.  The 
animals  usually  remain  calm  during  the  first  half  or  two-thirds  of  the  period ; 
but  they  then  become  more  or  less  agitated ;  and  this  state  continues  as  long  as 
their  temperature  remains  elevated.  On  the  last  day  of  life,  however,  whilst 
the  temperature  rapidly  falls,  this  restlessness  ceases,  and  gives  place  to  a  state 
of  stupor.  The  animal,  when  set  at  liberty,  sometimes  looks  round  with  astonish- 
ment, without  attempting  to  fly;  and  sometimes  closes  the  eyes,  as  if  in  a  state 
of  sleep.  Gradually  the  extremities  become  cold,  and  the  limbs  so  weak  as  no 
longer  to  be  able  to  sustain  the  animal  in  a  standing  posture ;  it  falls  over  on 
one  side,  and  remains-  in  any  position  in  which  it  may  be  placed,  without  attempt- 
ing to  move.  The  respiration  becomes  slower  and  slower ;  the  general  weakness 
increases,  and  the  insensibility  becomes  more  profound;  the  pupil  dilates;  and 
life  becomes  extinct,  sometimes  in  a  calm  and  tranquil  manner,  sometimes  after 
convulsive  actions  producing  opisthotonic  rigidity  of  the  body.  After  the  first 
day,  in  which  the  faeces  contain  the  residue  of  the  food  previously  taken,  their 
amount  is  very  small ;  and  they  seem  to  consist  principally  of  grass-green  biliary 
matter.  Towards  the  close  of  life,  they  contain  a  much  larger  quantity  of  water, 
even  when  none  has  been  ingested  by  the  animal ;  and  include  much  saline  matter 
in  addition  to  the  biliary. — The  average  loss  of  weight  in  the  warm-blooded 
animals,  experimented  on  by  M.  Chossat,  between  the  commencement  of  the 
period  of  Inanition  and  its  termination  by  death,  was  40  per  cent. ;  but  he  met 
with  a  considerable  variation  in  the  extremes,  which  seemed  to  depend  chiefly 
on  the  amount  of  fat  previously  accumulated  in  the  body;  those  animals  losing 
most  weight,  in  which  the  fat  had  been  most  abundant,  which  were  also  those 
that  lived  the  longest.3  Taking  40  per  cent,  as  the  mean,  M.  Chossat  obtained 

1  "  Recherches  Experim  en  tales  sur  1' Inanition,"  Paris,  1843. 

2  There  is  a  well-known  case  of  a  fat  pig,  which  was  buried  in  its  sty  for  160  days, 
under  thirty  feet  of  the  chalk  of  Dover  cliff ;  and  which  was  dug  out  alive  at  the  end  of 


394 


OF   FOOD,    AND   THE   DIGESTIVE   PROCESS. 


the  following  curious  results,  as  regards  the  relative  diminution  of  the  several 
tissues  and  organs  of  the  body;  those  which  lost  more  than  the  mean,  being  dis- 
tinguished from  those  which  lost  less. 

Parts  which  lose  less  than  40  per  cent. 

Muscular  coat  of  stomach  39.7 

Pharynx  and  oesophagus  34.2 

Skin        .         .         .  33.3 

Kidneys  .         .         .  31.9 

Respiratory  apparatus  22.2 

Osseous  system        .  16.7 

Eyes        .         .         .  10.0 

Nervous  system       .  1.9 


Parts  which  lose  more  than  40  per  cent. 

Fat          .         .         .         .         .         .  93.3 

Blood 75.0 

Spleen 71.4 

Pancreas 64.1 

Liver       .         . '                .         .         .  52.0 

Heart 44.8 

Intestines 42.4 

Muscles  of  Locomotion    .         .         .42.3 


The  points  most  worthy  of  note  in  the  above  table,  are  the  almost  complete 
removal  of  the  fat,  and  the  reduction  of  the  blood  to  three-fourths  its  normal 
amount;  whilst  the  nervous  system  undergoes  scarcely  any  loss.  It  would  seem, 
in  fact,  as  if  the  supervention  of  death  was  coincident  with  the  consumption  of 
all  the  disposable  combustive  material ;  and  that  up  to  that  point,  the  whole 
remaining  energy  of  nutrition  is  concentrated  upon  the  nervous  system.  And 
it  will  be  shown  hereafter  (CHAP,  xin.),  that  there  is  adequate  ground  for  con- 
sidering death  by  starvation  as  really  death  by  cold;  since  the  temperature  of  the 
body  is  maintained  with  little  diminution  until  the  fat  is  thus  consumed,  and 
then  rapidly  falls,  unless  it  be  kept  up  by  heat  externally  applied. — As  might 
be  expected  from  what  has  been  already  said  of  the  rapidity  of  interstitial 
change  at  the  earlier  periods  of  life  (§  130),  it  was  found  by  Chossat  that  the 
diurnal  loss  was  much  the  most  rapid  in  young  animals,  and  that  the  duration 
of  their  lives  when  deprived  of  food  was  consequently  far  less  than  that  of  adults. 
He  further  ascertained  that  the  results  of  insufficient  alimentation  were  in  the 
end  the  same  as  those  of  total  deprivation  of  food;  the  total  amount  of  loss 
being  almost  exactly  identical,  but  its  rate  being  less,  so  that  a  longer  time  was 
required  to  produce  it.  He  did  not  find  that  much  influence  was  exerted  on 
the  duration  of  life,  by  permitting  or  withdrawing  the  supply  of  water ;  but 
this  statement  does  not  apply  to  Man,  in  whom  death  supervenes  much  earlier 
when  liquid  as  well  as  solid  aliment  is  withheld ;  and  the  indifference  in  the  case 
of  Birds  is  probably  due  to  the  fact  that  they  ordinarily  drink  very  sparingly, 
and  eliminate  very  little  water  in  the  various  excretions. 

417.  The  most  prominent  symptoms  of  Starvation,  as  they  have  been  noted 
in  the  Human  subject,  are  as  follows : — In  the  first  place,  severe  pain  in  the 
epigastrium,  which  is  relieved  on  pressure ;  this  subsides  after  a  day  or  two,  but 
is  succeeded  by  a  feeling  of  weakness  and  "  sinking"  in  the  same  region ;  and 
an  insatiable  thirst  supervenes,  which,  if  water  be  withheld,  thenceforth  becomes 
the  most  distressing  symptom.  The  countenance  becomes  pale  and  cadaverous ; 
the  eyes  acquire  a  peculiar  wild  and  glistening  stare ;  and  general  emaciation 
soon  manifests  itself.  The  body  then  exhales  a  peculiar  fetor,  and  the  skin  is 
covered  with  a  brownish,  dirty-looking,  and  offensive  secretion.  The  bodily 
strength  rapidly  declines;  the  sufferer  totters  in  walking,  his  voice  becomes 
weak,  and  he  is  incapable  of  the  least  exertion.  The  mental  powers  exhibit  a 
similar  prostration ;  at  first  there  is  usually  a  state  of  stupidity,  which  gradually 
increases  to  imbecility,  so  that  it  is  difficult  to  induce  the  sufferer  to  make  any 
effort  for  his  own  benefit;  and  on  this  a  state  of  maniacal  delirium  frequently 
supervenes.  Life  terminates  either  in  the  mode  described  in  Chossat's  observa- 

that  time,  reduced  in  weight  from  160  Ibs.  to  40  Ibs.,  or  no  less  than  75  per  cent.  ("Trans. 
of  Linn.  Soc."  vol.  xi.  p.  411.)  The  extraordinary  prolongation  of  life  in  this  case  may 
be  attributed  to  the  retention  of  the  heat  of  the  body  by  the  non-conducting  power  of  the 
chalk ;  and  to  the  retention  of  its  moisture  by  the  saturation  of  the  air  in  its  immediate 
vicinity. 


OF   HUNGER   AND   THIRST.  —  STARVATION.  395 

tions,  or,  as  occasionally  happens,  in  a  convulsive  paroxysm.1 — On  post-mortem 
examination,  the  condition  of  the  body  is  found  to  be  such  as  the  results  of 
Chossat's  observations  would  indicate  ;  namely,  extreme  general  emaciation  and 
disappearance  of  fat,  diminution  in  the  bulk  of  the  principal  viscera,  and  almost 
complete  bloodlessness,  save  in  the  brain,  which  still  receives  its  usual  supply. 
It  is  specially  worthy  of  note,  that  the  coats  of  the  small  intestines  are  peculiarly 
thinned  (Donovan,  loc.  cit.),  so  that  they  become  almost  transparent;  and  that 
the  gall-bladder  is  almost  invariably  turgid  with  bile,  the  cadaveric  exudation 
of  which  tinges  the  surrounding  parts.  And  further,  the  body  rapidly  passes 
into  decomposition. 

418.  Now  it  is  peculiarly  worthy  of  note,  that  the  deficient  supply  of  new 
histogenetic  materials  appears  to  check  the  elimination   and  removal  of  those 
which  have  become  effete  ;  for  in  no  other  way  can  we  account  for  that  tendency 
to  putrescence,  which  is  so  remarkably  manifested  during  life  in  the  fetid  ex- 
halation and  in  the  peculiar  secretion  from  the  skin,  and  which  is  shown  after 
death  in  the  rapidity  with  which  putrefaction  supervenes.     Moreover,  towards 
the  close  of  many  exhausting  diseases,  the  fatal  termination  of  which  is  really 
due  to  a  chronic  inanition,  it  frequently  happens  that  a  "  colliquative  diarrhoea" 
comes  on,  which  must  be  considered  as  a  manifestation  of  the  general  disinte- 
gration that  is  making  progress  even  during  life. — Now  referring  to  the  condi- 
tions formerly  enumerated  (§  210),  as  those  which  favor  the  operation  of  zymo- 
tic poisons  in  the  body,  it  is  obvious  that  no  state  could  be  more  liable  to  it  than 
this;  since  we  have  not  merely  that  general  depression  of  the  vital  powers  which 
is  a  predisposing  cause  of  almost  any  kind  of  malady,  and  pre-eminently  so  of 
zymotic  diseases;  but  also  the  presence  of  a  large  amount  of  disintegrating  mat- 
ter in  the  blood  and  general  system,  which  forms  the  most  favorable  nidus  pos- 
sible for  the  reception  and  multiplication  of  such  poisons.     And  thus  it  happens 
that  pestilential  diseases  most  certainly  follow  in  the  wake  of  a  famine,  and 
carry  off  a  far  greater  number  than  perish  from  actual  starvation. 

419.  Another  class  of  phenomena,  however,  results  from  such  a  deficiency  of 
alimentation  as  is  not  adequate  to  produce  the  results  just  described;  provided 
this  deficiency  be  prolonged  for  a  considerable  length  of  time,  and  especially  if 
it  be  conjoined  with  other  unfavorable  conditions.     Of  this,  a  remarkable  ex- 
ample was  presented  at  the  Milbank  Penitentiary  in  1823.     The  prisoners  con- 
fined in  this  establishment,  who  had  previously  received  an  allowance  of  from 
31  to  33  oz.  of  dry  nutriment  daily,  had  this  allowance  suddenly  reduced  to 
21  oz.,  animal  food  being  at  the  same  time  almost  entirely  excluded.     They 
were  at  the  same  time  subjected  to  a  low  grade  of  temperature,  and  to  consider- 
able exertion;  and  were  confined  within  the  walls  of  a  prison  situated  in  the 
midst  of  a  marsh  which  is  below  the  level  of  the  adjoining  river.     The  prison 
had  been  previously  considered  healthy ;  but  in  the  course  of  a  few  months,  the 
health  of  a  large  proportion  of  the  inmates  began  to  give  way.     The  first  symp- 
toms were  loss  of  color,  and  diminution  of  flesh  and  strength;  subsequently, 
diarrhoea,  dysentery,  and  scurvy;  and  lastly,  adynamic  fevers,  or  headache,  ver- 
tigo, convulsions,  maniacal  delirium,  apoplexy,  &c.     The  smallest  loss  of  blood 
produced  syncope,  which  was  frequently  fatal ;  and  after  death,  ulceration  of 
the  mucous  lining  of  the  alimentary  canal  was  very  commonly  found.     Out  of 
860  prisoners,  no  fewer  than  437,  or  52  per  cent.,  were  thus  affected.     The 
influence  of  concurrent  conditions,  especially  of  previous  confinement,  was  here 
remarkably  shown ;  for  those  were  found  to  be  most  liable  to  disease  who  had 
been  in  prison  the  longest.     That  the  reduction  of  the  allowance  of  food,  how- 
ever, was  the  main  source  of  the  epidemic,  was  proved  by  the  two  following 

1  See  Rostan  in  "Diction,  de  Medecine,"  art.  "Abstinence;"  and  Dr.  Donovan's  ac- 
count of  the  Irish  famine  in  1847  in  the  "Dublin  Medical  Press,"  Feb.  1848. 


396  OF  FOOD,  AND  THE  DIGESTIVE  PROCESS. 

facts :  the  prisoners  employed  in  the  kitchen,  who  had  8  oz.  of  bread  additional 
per  day,  were  not  attacked,  except  three  who  had  only  been  there  a  few  days : 
and  after  the  epidemic  had  spread  to  a  great  extent,  it  was  found  that  the  addi- 
tion of  8  oz.  to  the  daily  allowance  of  vegetable  food,  and  J  oz.  to  the  animal, 
greatly  facilitated  the  operation  of  the  remedies  which  were  used  for  the  resto- 
ration of  health.1  Another  very  striking  example  of  the  effects  of  prolonged 
insufficiency  of  diet  has  been  furnished  by  the  ft  Maison  Centrale"  of  Nimes; 
which  is  a  large  penitentiary  containing  an  average  of  1200  prisoners.  The 
mortality  in  this  prison,  between  the  years  1829  and  1847,  varied  from  1  in 
7.85  to  1  in  23.88,  the  average  being  1  in  12.70;  whilst  the  average  mortality 
among  the  inhabitants  of  the  town  of  Nimes,  of  the  same  age  and  sex,  was  only 
1  in  49.9;  so  that  the  mortality  among  the  prisoners  was  from  two  to  six  times 
as  great  as  that  among  the  townspeople,  the  average  being  nearly  four  times. 
Several  causes  doubtless  concurred  to  produce  this  terrible  result;  but  whilst 
over-crowding  and  deficient  ventilation  were  constant,  deficiency  of  food,  amount 
of  labor  exacted,  and  depression  of  temperature  were  variable;  and  the  varia- 
tions in  the  rate  of  mortality  followed  these  last  so  uniformly,  that  there  could 
be  no  doubt  of  their  dependence  upon  them.3 

420.  It  is  a  curious  effect  of  insufficient  nutriment,  as  shown  by  the  inqui- 
ries of  Chossat  (op.  cit.),  that  it  produces  an  incapability  of  digesting  even  the 
limited  amount  supplied.     He  found  that,  when  turtle-doves  were  supplied  with 
limited  quantities  of  corn,  but  with  water  at  discretion,  the  whole  amount  of 
food  taken  was  scarcely  ever  actually  digested;  a  part  of  it  being  rejected  by 
vomiting,  or  passing  off  by  diarrhoea,  or  accumulating  in  the  crop.     It  seems  as 
if  the  vital  powers  were  not  sufficient  to  furnish  the  requisite  supply  of  gastric 
fluid,  when  the  body  began  to  be  enfeebled  by  insufficient  nutrition;  or  per- 
haps we  might  well  say,  the  materials  of  the  gastric  fluid  were  wanting.     Hence 
the  loathing  of  food,  which  is  often  manifested  by  those  who  have  been  sub- 
jected to  the  influence  of  an  insufficient  diet-scale  in  our  prisons  and  poor-houses, 
and  which  has  been  set  down  to  caprice  or  obstinacy,  and  punished  accordingly, 
may  be  actually  a  proof  of  the  deficiency  of  the  supply,  which  we  might  expect 
to  have  been  voraciously  devoured,  if  really  less  than  the  wants  of  the  system 
require. 

421.  It  is  extremely  important  that  the  Medical  Practitioner  should  be  aware, 
that  many  of  the  phenomena  above  described  may  be  induced  by  the  adoption 
of  a  system  of  too  rigid  abstinence  in  the  treatment  of  various  diseases ;  and 
that  they  have  been  frequently  confounded  with  the  symptoms  of  the  malady 
itself,  and  have  led  to  an  entirely  erroneous  method  of  treating  it.     "  Many 
cases,"  says  Dr.  Copland,3  "  have  occurred  to  me  in  practice,  where  the  anti- 
phlogistic regimen,  which  had  been  too  rigidly  pursued,  was  itself  the  cause  of 
the  very  symptoms  which  it  was  employed  to  remove.     Of  these  symptoms,  the 
affection  of  the  head  and  delirium  are  the  most  remarkable,  and  the  most  readily 
mistaken  for  an  actual  disease  requiring  abstinence  for  its  removal."     The  ex- 
perience of  those,  especially,  who  are  largely  engaged  in  consulting  practice, 
must  have  furnished  numerous  illustrations  of  the  above  statement.     Dr.  Cop- 
land mentions  the  following:  "  A  professional  man  had  been  seized  with  fever, 
for  which  a  too  rigid  abstinence  was  enforced,  not  only  during  its  continuance, 
but  also  during  convalescence.     Delirium  had  been  present  at  the  height  of  the 
fever,  and  recurred  when  the  patient  was  convalescent.     A  physician  of  emi- 
nence in  maniacal  cases  was  called  to  him,  and  recommended  that  he  should  be 

1  See  Dr.  Latham  "On  the  Diseases  in  the  Milbank  Penitentiary,"  1824. 

2  See  the  highly-instructive  account  of  this  series  of  occurrences,  by  M.  Boileau-Cas- 
telnau,  chief  physician  to  the  "Maison  Centrale,"  in  Ann.  d' Hygiene  Publ.,  Janv.,  1849. 

3  "  Dictionary  of  Practical  Medicine,"  vol.  i.  p.  26. 


MOVEMENTS    OF   THE   ALIMENTARY   CANAL.  397 

removed  to  a  private  asylum.  Before  this  was  carried  into  effect,  I  was  re- 
quested to  see  him.  A  different  treatment  and  regimen,  with  a  gradual  increase 
of  nourishment,  were  adopted;  and  he  was  well  in  a  few  days,  and  within  a 
fortnight  returned  to  his  professional  avocations." 

422.  The  time  during  which  life  can  be  supported  under  total  abstinence  from 
food  or  drink,  is  usually  stated  to  vary  from  eight  to  ten  days;1  the  period  may  be 
greatly  prolonged,  however,  by  the  occasional  use  of  water,  and  still  more  by  a 
very  small  supply  of  food;  or  even,  it  would  seem,  by  a  moist  condition  of  the 
surrounding  atmosphere,  which  obstructs  the  exhalation  of  liquid  from  the 
body.     Thus  Fodere  mentions  that  some  workmen  were  extracted  alive,  after 
fourteen  days'  confinement  in  a  cold  damp  vault,  in  which  they  had  been  buried 
under  a  ruin.     Dr.  Sloan  has  given  an  account3  of  the  case  of  a  healthy  man 
set.  65,  who  was  found  alive  after  having  been  shut  up  in  a  coal-mine  for  twenty- 
three  days,  during  the  first  ten  of  which  he  was  able  to  procure  and  swallow  a 
small  quantity  of  foul  water;  he  was  in  a  state  of  extreme  exhaustion,  and 
died  three  days  afterwards,  notwithstanding  the  attempts  made  to  recover  him. 
It  would  seem  as  if  certain  conditions  of  the  Nervous  system,  especially  those 
attended  with  peculiar  emotional  excitement,  are  favorable  to  the  prolongation 
of  life  under  such  circumstances.     Thus,  in  a  case  recorded  by  Dr.  Willan,  of 
a  young  gentleman  who  starved  himself  under  the  influence  of  a  religious  delu- 
sion, life  was  prolonged  for  60  days;  during  the  whole  of  which  time  nothing 
else  was  taken  than  a  little  orange-juice.     In  a  somewhat  similar  case  which 
occurred  under  the  Author's  notice,  in  the  person  of  a  young  French  lady,  more 
than  15  days  elapsed  between  the  time  that  she  ceased  to  eat  regularly,  and  the 
time  of  her  being  compelled  to  receive  nourishment;  during  this  period  she 
took  a  good  deal  of  exercise,  and  her  strength  seemed  to  suffer  but  little,  although 
she  swallowed  solid  food  only  once,  and  then  in  small  quantity.     Again,  in 
certain  states  of  the  system  commonly  known  as  "  hysterical,"  there  is  frequently 
a  very  remarkable  disposition  for  abstinence,  and  power  of  sustaining  it.     In  a 
case  of  this  kind  which  occurred  under  the  Author's  own  observation,  a  young 
lady,  who  had  just  before  suffered  severely  from  the  tetanic  form  of  Hysteria, 
was  unable  to  take  food  for  three  weeks.     The  slightest  attempt  to  introduce  a 
morsel  of  solid  matter  into  the  stomach,  occasioned  violent  efforts  at  vomiting; 
and  the  only  nourishment  taken  during  the  period  mentioned,  was  a  cup  of  tea 
once  or  twice  a  day;  and  on  many  days  not  even  this  was  swallowed.     Yet  the 
strength  of  the  patient  rather  increased  than  diminished  during  this  period;  her 
muscles  became  firmer,  and  her  voice  more  powerful.    It  may  be  well  to  remark 
that,  under  such  circumstances,  the  continual  persuasions  of  anxious  friends  are 
very  injurious  to  the  patient;  whose  return  to  her  usual  state  will  probably  take 
place  the  earlier,  the  more  completely  she  is  left  to  herself. 

3.  Movements  of  the  Alimentary  Canal. 

423.  The  motions  by  which  Food  is  conveyed  to  the  Mouth  and  introduced 
into  its  cavity,  constituting  the  acts  of  Prehension  and  Ingestion,  are  ordinarily 
considered  to  be  voluntary,  at  least  in  the  adult ;  and  it  is  indubitable  that  the 
Will  has  entire  control  over  them.     Nevertheless,  they  belong  to  that  class  of 
"  secondarily  automatic"  movements,  whose  character  has  been  already  noticed 
(§  392) ;  and  like  the  movements  of  locomotion,  may  be  kept  up  when  the  will 
is  in  abeyance,  by  the  suggesting  and  guiding  influence  of  sensations,  thus 

1  There  seems  adequate  evidence  that  a  state  which  may  be  characterized  as  one  of  Syn- 
cope may  be  prolonged  for  many  days  or  even  weeks,  provided  the  temperature  of  the  body 
be  not  too  much  reduced.     This  class  of  facts,  however,  will  be  more  appropriately  con- 
sidered hereafter  (CHAP,  xiv.,  SECT.  7). 

2  "Medical  Gazette/'  vol.  xvii.  p.  389. 


398  OF  FOOD,  AND  THE  DIGESTIVE  PROCESS. 

being  performed  under  the  same  essential  conditions  as  the  purely  "  consensual" 
or  "  sensori-motor"  actions.1  The  necessity  of  guiding  sensations  for  their 
performance  is  made  evident  by  one  of  Sir  C.  Bell's  experiments,  the  wrong 
interpretation  of  whose  results  originally  led  him  to  an  erroneous  view  of  the 
functions  of  the  Fifth  pair  of  nerves.  He  found  that  an  Ass,  in  which  the 
infra-orbital  branch  of  this  nerve  had  been  divided,  made  no  attempt  to  pick  up 
oats  with  its  lip,  although  the  animal  saw  them,  bent  down  its  head  with  the 
obvious  purpose  of  ingesting  them,  and  brought  its  lip  into  absolute  contact 
with  them;  hence  he  concluded  that  the  power  of  motion  was  destroyed  in  the 
lip,  when  it  was  in  reality  only  the  guiding  sensation  that  was  deficient,  the 
motor  power  being  supplied  by  the  Facial  nerve  or  Portio  dura.  But  although 
the  movements  concerned  in  the  ingestion  of  food  in  the  adult  require  the  co- 
operation of  the  sensorial  centres,  this  is  not  the  case  with  the  act  of  suction  in 
the  Infant,  which  may  be  considered  as  essentially  a  respiratory  act,  and  which 
is  performed  not  merely  without  will,  but  even  without  consciousness.  The  ex- 
periments provided  for  us  by  nature,  in  the  production  of  Anencephalous  mon- 
strosities, fully  prove  that  the  "  nervous  circle"  whereby  the  lips  and  respiratory 
organs  are  connected  with  the  Medulla  Oblongata,  is  alone  sufficient  for  its  per- 
formance ;  and  Mr.  Grainger  has  sufficiently  established  the  same,  by  experiment 
upon  puppies  whose  brain  had  been  removed.  He  adds  that,  as  one  of  these 
brainless  puppies  lay  on  its  side,  sucking  the  finger  which  was  presented  to  its 
lips,  it  pushed  out  its  feet  in  the  same  manner  as  young  pigs  exert  theirs  against 
the  sow's  dugs.3  The  Human  infant  or  other  young  Mammal,  however,  performs 
movements  which  are  of  a  higher  character  than  this;  going  in  search,  as  it  were, 
of  the  source  of  its  nourishment;  towards  which  it  seems  to  be  especially 
guided  by  the  sense  of  Smell.  Such  movements  are  probably  to  be  considered 
as  "  consensual,"  and  as  deriving  their  first  stimulus  from  tlie  internal  feelings 
of  hunger,  whilst  their  direction  is  given  by  the  guiding  sensation  which  indi- 
cates the  situation  of  the  appropriate  aliment.  That  no  such  actions  are  called 
into  play  by  the  same  stimuli,  after  the  expiry  of  the  period  during  which  the 
young  Mammal  is  dependent  upon  its  maternal  parent  for  its  nourishment, 
seems  to  indicate  that  the  reactive  power  of  the  nervous  centres  on  which  they 
are  dependent  is  only  temporary,  and  that  it  ceases  with  the  need  for  its  exer- 
cise ;  the  child  growing-out  (so  to  speak)  of  this  automatic  power,  whilst  it  grows- 
into  many  new  ones — those  especially,  which  are  connected  with  the  generative 
function. 

424.  The  food  thus  introduced  into  the  mouth,  is  subjected  (unless  it  be  al- 
ready in  a  state  which  needs  no  further  reduction)  to  the  process  of  Mastication. 
This  is  evidently  an  operation  of  great  importance  in  preparing  the  substances 
to  be  afterwards  operated  on  for  the  action  of  their  solvent;  and  it  exactly  cor- 

1  This,  the  Author  thinks,  will  be  conformable  to  the  experience  of  most  of  his  readers ; 
who  will  find,  if  they  analyze  their  own  consciousness,  that  they  continue  to  eat  while  their 
whole  attention  is  given  to  some  abstract  train  of  thought,  or  to  some  external  object.     But 
a  remarkable  case  will  be  cited  hereafter.  (CHAP.  xiv.  SECT.  7),  which  fully  confirms  the 
view  here  advanced  ;  the  movements,  not  merely  of  the  lips  and  jaws,  but  those  by  which 
food  was  conveyed  to  the  mouth,  having  been  carried  on  automatically,  when  once  (so  to 
speak)  the  spring  was  touched  by  which  they  were  set  in  action. 

2  "Observations  on  the  Structure  and  Functions  of  the  Spinal  Cord,"  pp.  80,  81. — The 
actions  of  the  mammary  foetus  of  the  Kangaroo,  described  by  Mr.  Morgan,  furnish  a  very 
interesting  exemplification  of  the  same  function  of  the  Spinal  Cord ;  this  creature,  resem- 
bling an  earth-worm  in  appearance,  and  only  about  fourteen  lines  in  length,  with  a  brain 
corresponding  in  degree  of  development  to  that  of  a  human  foetus  of  the  ninth  week, 
executes  regular,  but  slow,  movements  of  respiration,  adheres  firmly  to  the  point  of  the 
nipple,  and  moves  its  limbs  when  disturbed.     The  milk  is  forced  into  the  oesophagus  by  a 
compressor  muscle,  with  which  the  mamma  of  the  parent  is  provided.     "Can  it  be  im- 
agined," very  justly  asks  Mr.  Grainger,  "that  in  this  case  there  are  sensation  and  volition, 
in  what  can  be  proved  anatomically  to  be  a  foetus  ?" 


MOVEMENTS   OF   THE   ALIMENTARY   CANAL.  —  MASTICATION.      399 

responds  with  the  trituration  to  which  the  Chemist  would  submit  any  solid  mat- 
ter, that  he  might  present  it  in  the  most  advantageous  form  to  a  digestive  men- 
struum. The  complete  disintegration  of  the  alimentary  matter  is,  therefore,  of 
great  consequence;  and,  if  imperfectly  effected,  the  subsequent  processes  are 

Fig.  116. 


A  view  of  the  Organs  of  Digestion,  opened  in  nearly  their  whole  length ;  a  portion  of  the  oesophagus  has 
been  removed  on  account  of  want  of  space  in  the  figure ;  the  arrows  indicate  the  course  of  substances  along 
the  canal:'  1,  the  upper  lip,  turned  off  the  mouth;  2,  its  frsenum;  3,  the  lower  lip,  turned  down;  4,  its  frse- 
num ;  5,  5,  inside  of  the  cheeks,  covered  by  the  lining  membrane  of  the  mouth ;  6,  points  to  the  opening  of 
the  duct  of  Steno;  7,  roof  of  the  mouth;  8,  lateral  half  arches;  9,  points  to  the  tonsils;  10,  velum  pendulum 
palati ;  11,  surface  of  the  tongue ;  12,  papillae  near  its  point ;  13,  a  portion  of  the  trachea ;  14,  the  oesophagus ; 
15,  its  internal  surface ;  16,  inside  of  the  stomach ;  17,  its  greater  extremity  or  great  cul-de-sac ;  18,  its  lesser 
extremity  or  smaller  cul-de-sac;  19,  its  lesser  curvature;  20,  its  greater  curvature;  21,  the  cardiac  orifice;  22, 
the  pyloric  orifice ;  23,  upper  portion  of  duodenum;  24,  25,  the  remainder  of  the  duodenum;  26,  its  valvulae 
conniventes ;  27,  the  gall-bladder ;  28,  the  cystic  duct ;  29,  division  of  hepatic  ducts  in  the  liver ;  30,  hepatic 
duct ;  31,  ductus  communis  choledochus ;  32,  its  opening  into  the  duodenum ;  33,  ductus  Wirsungii,  or  pan- 
creatic duct ;  34,  its  opening  into  the  duodenum ;  35,  upper  part  of  jejunum ;  36,  the  ileum ;  37,  some  of  the 
valvulse  conniventes;  38,  lower  extremity  of  the  ileum;  39,  ileo-colic  valve;  40,  41,  coecum,  or  caput  coli;  42, 
appendicula  vermiformis;  43,  44,  ascending  colon;  45,  transverse  colon;  46,  47,  descending  colon;  48,  sigmoid 
flexure  of  the  colon ;  49,  upper  portion  of  the  rectum ;  50,  its  lower  extremity;  51,  portion  of  the  levator-am 
muscle ;  52,  the  anus. 


400  OF   FOOD,    AND   THE   DIGESTIVE   PROCESS. 

liable  to  derangement.  Such  derangement  we  continually  meet  with;  for  there 
is  not,  perhaps,  a  more  frequent  source  of  Dyspepsia  than  imperfect  mastication, 
whether  resulting  from  the  haste  with  which  the  food  is  swallowed,  or  from  the 
want  of  the  instruments  proper  for  the  reducing  operation.  The  mechanical  dis- 
integration of  the  food  is  manifestly  aided  by  Insalivation ;  but  the  admixture 
of  Saliva  also  exerts,  as  we  shall  hereafter  see  (§  439),  a  very  marked  influence 
on  the  chemical  composition  of  certain  of  its  constituents. — The  movements  of 
Mastication,  still  more  than  those  already  adverted  to,  although  under  the  com- 
plete control  of  the  Will,  and  originally  dependent  upon  it  for  their  excitation, 
come  at  last  to  be  of  so  habitual  a  character,  that  they  continue  when  the  direct 
influence  of  the  will  is  withdrawn,  the  influence  of  the  "  guiding  sensation," 
however,  being  essential  to  their  performance.1  Every  one  is  conscious  that  the 
act  of  mastication  may  be  performed  as  well  when  the  mind  is  attentively  dwell- 
ing on  some  other  object,  as  when  directed  to  it;  but,  in  the  former  case,  we 
are  rather  apt  to  go  on  chewing  and  rechewing  what  is  already  fit  to  be  swal- 
lowed, simply  because  the  will  does  not  exert  itself  to  check  the  action,  and  to 
carry  the  food  backwards  within  the  reach  of  the  muscles  of  deglutition.  This 
conveyance  of  food  backwards  to  the  fauces  is  a  distinctly  voluntary  act;  and  it 
is  necessary  that  it  should  be  guided  by  the  sensation  which  there  results  from 
the  contact  it  induces.  If  the  surface  of  the  pharynx  were  as  destitute  of 
sensation  as  is  the  lower  part  of  the  oesophagus,  we  should  not  know  when  we 
had  done  what  was  necessary  to  excite  its  muscles  to  operation. — The  muscles 
concerned  in  the  Mastication  of  food  are  nearly  all  supplied  by  the  third  branch 
of  the  Fifth  pair,  a  large  proportion  of  which  is  well  known  to  have  a  motor 
character.  Many  of  these  muscles,  especially  those  of  the  cheeks,  are  also  sup- 
plied by  the  Facial  nerve ;  and  yet,  if  the  former  be  paralyzed,  the  latter  can- 
not stimulate  them  to  the  necessary  combined  actions.  Hence  we  see  that  the 
movements  are  of  an  associated  character,  their  due  performance  being  depend- 
ent on  the  part  of  the  nervous  centres  from  which  the  motor  influence  origi- 
nates.3 If  the  Fifth  pair,  on  the  other  hand,  be  uninjured,  whilst  the  Portio 
Dura  is  paralyzed,  the  movements  of  Mastication  are  performed  without  diffi- 
culty; whilst  those  connected  in  any  way  with  the  Respiratory  function,  or  with 
Expression,  are  paralyzed.  If,  again,  the  sensory  portion  of  the  Fifth  pair  be 
paralyzed,  the  act  of  Mastication  is  very  imperfectly  performed,  even  though 
the  motor  power  be  not  in  the  least  impaired ;  for  the  muscles  cannot  be  made 
to  perform  the  requisite  associated  movements  without  the  guidance  of  sensa- 
tions; so  that  the  morsel  lodges  between  the  teeth  and  the  cheek,  or  beneath  the 
tongue,  and  can  with  difficulty  be  kept  in  the  appropriate  position. 

1  Thus,  in  the  curious  case  formerly  referred  to  (§  373,  note),  food  can  only  be  admin- 
istered by  carrying  back  the  spoon  containing  it,  until  it  touches  the  fauces  and  thus  ex- 
cites an  act  of  deglutition.     Sensation  being  here  entirely  deficient,  there  is  nothing  to 
excite  or  to  guide  the  movements  of  the  muscles  of  the  mouth  and  tongue. 

2  Comparative  Anatomy  furnishes  the  key  to  these  phenomena,  which  seem  at  first  sight 
to  be  somewhat  strange. — Among  Invertebrate  animals  generally,  the  Respiratory  organs 
are  completely  unconnected  with  the  mouth ;  and  a  very  distinct  set  of  muscles  is  provided 
to  keep  them  in  action.    These  muscles  have  separate  ganglia  as  the  centres  of  their  opera- 
tions ;  and  these  ganglia  are  only  connected  indirectly  with  those  of  the  sensori-motor 
system.     The  same  is  the  case,  in  regard  to  the  introduction  of  the  food  into  the  digestive 
apparatus.     The  muscles  concerned  in  this  operation  have  their  own  centres — the  Stomato- 
gastric  and  Pharyngeal  ganglia,  which  are  not  very  closely  connected  with  the  cephalic, 
or  with  the  respiratory,  or  with  those  of  general  locomotion.     Now  in  the  Vertebrata,  the 
distinct  organs  have  been  so  far  blended  together,  that  the  same  muscles  serve  the  purposes 
of  both;  but  the  different  sets  of  movements  of  these  muscles  are  excited  by  different 
nerves ;  and  the  effect  of  division  of  either  nerve  is  to  throw  the  muscle  out  of  connection 
with  the  function  to  which  that  nerve  previously  rendered  it  subservient — as  much  as  if 
the  muscle  were  separated  from  the  nervous  system  altogether. 


MOVEMENTS   OP   THE   ALIMENTARY   CANAL. — DEGLUTITION.       401 

425.  When  the  reduction  of  the  food  in  the  mouth  has  been  sufficiently  ac- 
complished, it  is  carried  into  the  Pharynx,  and  thence  propelled  down  the 

Fig.  117. 


A  view  of  the  Muscles  of  the  Tongue,  Palate,  Larynx,  and  Pharynx— as  well  as  the  position  of  the  upper 
portion  of  the  (Esophagus,  as  shown  by  a  vertical  section  of  the  head ;  1, 1,  the  vertical  section  of  the  head ; 
2,  points  to  the  spinal  canal ;  3,  section  of  the  hard  palate ;  4,  inferior  spongy  bone ;  5,  middle  spongy  bone  ; 
6,  orifice  of  the  right  nostril ;  7,  section  of  the  inferior  maxilla;  8,  section  of  the  os  hyoides ;  9,  section  of  the 
epiglottis ;  10,  section  of  the  cricoid  cartilage ;  11,  the  trachea,  covered  by  its  lining  membrane ;  12,  section  of 
sternum ;  13,  inside  of  the  upper  portion  of  the  thorax ;  14,  genio-hyoglossus  muscle ;  15,  its  origin ;  16, 17, 
the  fan-like  expansion  of  the  fibres  of  this  muscle ;  18,  superficial  linguae  muscle ;  19,  verticalis  linguae  mus- 
cle; 20,  genio-hyoideus  muscle;  21,  mylo-hyoideus  muscle;  22,  anterior  belly  of  digastricus;  23,  section  of 
platysma  myoides ;  24,  levator  menti ;  25,  orbicularis  oris ;  26,  orifice  of  Eustachian  tube ;  27,  levator  palati ; 
28,  internal  pterygoid ;  29,  section  of  velum  pendulum  palati,  and  azygos  uvulae  muscle ;  30,  stylo  pharyn- 
geus ;  31,  constrictor  pharyngis  superior ;  32,  constrictor  pharyngis  medius ;  33,  insertion  of  stylo-pharyngeus ; 
34,  constrictor  pharyngis  inferior ;  35, 36, 37,  muscular  coat  of  oesophagus ;  38,  thyreo-arytenoid  muscle  and  liga- 
ments, and  above  is  the  ventricle  of  Galen ;  39,  section  of  arytenoid  cartilage ;  40,  border  of  sterno-hyoideus. 

oesophagus  into  the  stomach,  by  a  set  of  associated  movements,  which,  taken 
together,  constitute  the  act  of  Deglutition.  These  movements  were  first  de- 
scribed in  detail  by  Magendie;  but  his  account  requires  some  modification, 
through  the  more  recent  observations  of  Dzondi.1 — The  first  stage  in  the  pro- 
cess is  the  carrying  back  of  the  food  until  it  has  passed  the  anterior  palatine 
arch;  this,  which  is  effected  by  the  approximation  of  the  tongue  and  the  palate, 
is  a  purely  voluntary  movement.  In  the  second  stage,  the  tongue  is  carried 
still  further  backwards,  and  the  larynx  is  drawn  forwards  under  its  root,  so  that 
the  epiglottis  is  pressed  down  over  the  rima  glottidis.  The  muscles  of  the  ante- 
rior palatine  arch  contract  after  the  morsel  has  passed  it,  and  assist  its  passage 
backwards;  these,  with  the  tongue,  cut  off  completely  the  communication  be- 
tween the  fauces  and  the  mouth.  At  the  same  time,  the  muscles  of  the  poste- 
rior palatine  arch  contract  in  such  a  manner  as  to  cause  the  sides  of  the  arch  to 
approach  each  other  like  a  pair  of  curtains,  so  that  the  passage  from  the  fauces 
into  the  posterior  nares  is  nearly  closed  by  them;  and  to  the  cleft  between  the 

1  See  Prof.  Midler's  "  Elements  of  Physiology"  (translated  by  Dr.  Baly),  p.  501. 
26 


402  OF   FOOD,  AND   THE   DIGESTIVE   PROCESS. 

approximated  sides,  the  uvula  is  applied  like  a  valve.  A  sort  of  inclined  plane, 
directed  obliquely  downwards  and  backwards,  is  thus  formed;  and  the  morsel 
slides  along  it  into  the  pharynx,  which  is  brought  up  to  receive  it.  Some  of 
these  acts  may  be  performed  voluntarily;  but  the  combination  of  the  whole  is 
automatic.  The  third  stage  of  the  process,  the  propulsion  of  the  food  down  the 
oesophagus,  then  commences.  This  is  accomplished,  in  the  upper  part,  by  means 
of  the  constrictors  of  the  pharynx;  and  in  the  lower,  by  the  muscular  coat  of 
the  oesophagus  itself.  When  the  morsels  are  small,  and  are  mixed  with  much 
fluid,  the  undulating  movements  from  above  downwards  succeed  each  other  very 
rapidly;  this  may  be  well  observed  in  Horses  whilst  drinking;  large  morsels, 
however,  are  frequently  some  time  in  making  their  way  down.  Each  portion 
of  food  and  drink  is  included  in  the  contractile  walls,  which  are  closely  applied 
to  it  during  the  whole  of  its  transit.  The  gurgling  sound,  which  is  observed 
when  drink  is  poured  down  the  throat  of  a  person  in  articulo  mortis,  is  due  to 
the  want  of  this  contraction.  The  whole  of  the  third  stage  is  completely  in- 
voluntary.— At  the  point  where  the  oesophagus  enters  the  stomach,  the  "cardiac 
orifice"  of  the  latter,  there  is  a  sort  of  sphincter,  which  is  usually  closed,  but 
which  opens  when  sufficient  pressure  is  made  on  it  by  accumulated  food,  closing 
again  when  this  has  passed,  so  as  to  retain  it  in  the  stomach. 

426.  The  purely  automatic  nature  of  the  act  of  Deglutition  is  shown  by  the 
fact  that  no  attempts  on  our  own  part  will  succeed  in  performing  it  really 
voluntarily.     In  order  to  excite  it,  we  must  supply  some  stimulus  to  the  fauces. 
A  very  small  particle  of  solid  matter,  or  a  little  fluid  (saliva,  for  instance),  or 
the  contact  of  the  back  of  the  tongue  itself,  will  be  sufficient;  but  without 
either  of  these,  we  cannot  swallow  at  will.     Nor  can  we  restrain  the  tendency, 
when  it  is  thus  excited  by  a  stimulus ;  every  one  knows  how  irresistible  it  is, 
when  the  fauces  are  touched  in  any  unusual  manner ;  and  it  is  equally  beyond 
the  direct  control  of  the  will,  in  the  ordinary  process  of  eating — voluntary  as 
we  commonly  regard  this.     The  only  mode  in  which  the  will  can  influence  it, 
is  by  regulating  the  approach  of  the  stimulus  necessary  to  excite  it ;  thus,  we 
voluntarily  bring  a  morsel  of  food,  or  a  little  fluid,  into  contact  with  the  surface 
of  the  fauces,  and  an  act  of  deglutition  is  then  involuntarily  excited;  or  we 
may  voluntarily  keep  all  stimulus  at  a  distance,  and  no  effort  of  the  will  can 
then  induce  the  action.     Moreover,  this  action  is  performed,  like  that  of  respi- 
ration, when  the  power  of  the  will  is  suspended,  as  in  profound  sleep,  or  in 
apoplexy  affecting  only  the  brain;  and  it  does  not  seem  to  be  at  all  affected  by 
the  entire  removal  of  the  brain,  in  an  animal  that  can  sustain  the  shock  of  the 
operation;  being  readily  excitable,  on  stimulating  the  fauces,  so  long  as  the 
nervous  structure  retains  its  functions.     This  has  been  experimentally  proved 
by  Dr.  M.  Hall ;  and  it  harmonizes  with  the  natural  experiment  sometimes 
brought  under  our  notice  in  the  case  of  an  anencephalous  infant,  in  which  the 
power  of  swallowing  seems  as  vigorous  as  in  the  perfect  one.     But,  if  the  nerv- 
ous circle  be  destroyed,  either  by  division  of  the  trunks,  or  by  injury  of  any 
kind  to  the  portion  of  the  nervous  centres  connected  with  them,  the  action  can 
no  longer  be  performed;  and  thus  we  see  that,  when  the  effects  of  apoplexy  are 
extending  themselves  from  the  brain  to  the  spinal  cord,  whilst  the  respiration 
becomes  stertorous,  the  power  of  deglutition  is  lost,  and  then  respiration  also 
speedily  ceases. 

427.  Our  knowledge  of  the  nerves  specially  concerned  in  this  action  is  prin- 
cipally due  to  the  very  careful  and  well-conducted  experiments  of  Dr.  J.  Reid.1 
— The  distribution  of  the  Glosso-pharyngeal  evidently  points  it  out  as  in  some 
way  connected  with  it ;  but  this,  when  carefully  examined,  discloses  the  im- 

1  "Edinb.  Med.  and  Surg.  Journ.,"  vol.   xlix. ;  and  "Physiological,  Anatomical,  and 
Pathological  Researches,"  CHAP.  iv. 


MOVEMENTS   OP   THE   ALIMENTARY   CANAL. DEGLUTITION.      403 

portant  fact  that  the  nerve  scarcely  sends  any  of  its  branches  to  the  muscles 
which  they  enter,  these  mostly  passing  through  them,  to  be  distributed  to  the 
superjacent  mucous  surface  of  the  tongue  and  fauces.     Further,  when  the  trunk 
is  separated  from  the  nervous  centres,  irritation  produces  scarcely  any  muscular 
movements.    Hence  it  is  not  in  any  great  degree  an  "efferent"  or  motor  nerve; 
and  its  distribution  would  lead  us  to  suppose  its  chief  function  to  be  "afferent;" 
namely,  the  conveyance  of  impressions  from  the  surface  of  the  fauces  to  the 
Medulla  Oblongata.     This  inference  is  fully  confirmed  by  the  fact  that,  so  long 
as  its  trunk  is  in  connection  with  the  centre,  and  the  other  parts  are  uninjured, 
pinching,  or  other  severe  irritation  of  the  Glosso-pharyngeal,  will  often  excite 
distinct  acts  of  deglutition.    Such  irritation,  however,  may  excite  only  convulsive 
twitches,  instead  of  the  regular  movements  of  swallowing ;  and  it  is  evident  that 
here,  as  elsewhere,  the  impressions  made  upon  the  extremities  of  the  nerves  are 
much  more  powerful  excitors  of  reflex  movement  than  those  made  upon  the 
trunk,  though  the  latter  are  more  productive  of  pain.     It  was  further  observed 
by  Dr.  Reid,  that  this  effect  was  produced  by  pinching  the  pharyngeal  branches 
only ;  no  irritation  of  the  lingual  division  being  effectual  to  the  purpose. — If, 
then,  the  muscles  of  deglutition  be  not  immediately  stimulated  to  contraction 
by  the  Glosso-pharyngeal  nerve,  it  remains  to  be  inquired,  by  what  nerve  the 
motor  influence  is  conveyed  to  them  from  the  Medulla  Oblongata ;  and  Dr.  Reid 
was  equally  successful  in  proving  that  this  function  is  chiefly  performed  by  the 
Pharyngeal  branches  of  the  Pneumogastric.     Anatomical  examination  of  their 
distribution  shows,  that  they  lose  themselves  in  the  muscles  of  the  pharynx  ; 
and  whilst  no  decided  indications  of  suffering  can  be  produced  by  irritating  them, 
evident  contractions  are  occasioned,  when  the  trunk,  separated  from  the  brain, 
is  pinched  or  otherwise  stimulated. — It  appears,  however,  that  neither  is  the 
Glosso-pharyngeal  the  sole  excitor  nerve,  nor  are  pharyngeal  branches  of  the 
Pneumogastric  the  sole  motor  nerves,  concerned  in  deglutition ;  for,  after  the 
former  has  been  perfectly  divided  on  each  side,  the  usual  movements  can  still 
be  excited,  though  with  less  energy ;  and,  after  the  latter  have  been  cut,  the 
animal  retains  the  means  of  forcing  small  morsels  through  the  pharynx,  by  the 
action  of  the  muscles  of  the  tongue  and  neck.     From  a  careful  examination  of 
the  actions  of  deglutition,  and  of  the  influence  of  various  nerves  upon  them, 
Dr.  Reid  drew  the  following  conclusions  :  The  excitor  impressions  are  conveyed 
to  the  Medulla  Oblongata  chiefly  through  the  Glosso-pharyngeal,  but  also  along 
the  branches  of  the  Fifth  pair  distributed  upon  the  fauces,  and  probably  along 
the  superior  Laryngeal  branches  of  the  Pneumogastric  distributed  upon  the 
pharynx.     The  motor  influence  passes  chiefly  along  the  Pharyngeal  branches 
of  the  Pneumogastric ;  along  the  branches  of  the   Hypoglossal,  distributed  to 
the  muscles  of  the  tongue,  and  to  the  sterno-hyoid,  sterno-thyroid,  and  thyro- 
hyoid  muscles ;  along  the  motor  filaments  of  the  Recurrent  laryngeals ;  along 
some  of  the  branches  of  the  Fifth,  supplying  the  elevator  muscles  of  the  lower 
jaw;  along  the  branches  of  the  Facial,  ramifying  upon  the  digastric  and  stylo- 
hyoid  muscles  and  upon  those  of  the  lower  part  of  the  face  ;  and  probably  along 
some  of  the  branches  of  the  Cervical  plexus,  which  unite  themselves  to  the 
Descendens  noni.     It  was  further  observed  by  Dr.  Reid  (Op.  cit.,  pp.  258 — 260), 
that  the  stylo-pharyngeus  muscle  is  usually  thrown  into  contraction,  when  the 
roots  of  the  Glosso-pharyngeal  nerve  are  irritated;  and  this  has  also  been  noticed 
by  Mayo,  Volkmann,  and  others  ;*  so  that  we  are  to  consider  the  Glosso-pharyn- 
geal as  a  motor  nerve,  in  so  far  as  that  muscle  is  concerned. 

1  It  seems  not  improbable  that  the  discrepant  results  obtained  by  different  experimenters 
on  this  point  are  partly  to  be  explained  by  differences  in  the  distribution  of  the  nerves  in 
the  several  animals  operated  on.  .  .' 


404  OF   FOOD,    AND   THE   DIGESTIVE   PROCESS. 

428.  When  the  food  has  been  propelled  downwards  by  the  Pharyngeal  muscles, 
so  far  as  their  action  extends,  its  further  progress  through  the    (Esophagus  is 
effected  by  a  kind  of  peristaltic  contraction  of  the  muscular  coat  of  the  tube  itself. 
This  movement  is  not,  however,  due  only  to  the  direct  stimulus  of  the  muscular 
fibre  by  the  pressure  of  the  food,  as  it  seems  to  be  in  the  lower  part  of  the  ali- 
mentary canal;  for  Dr.  J.  Reid  has  found,  by  repeated  experiment,  that  the 
continuity  of  the  oesophageal  branches  of  the  Pneumogastric  with  the  Medulla 
Oblongata,  is  necessary  for  the  rapid  propulsion  of  the  food;  so  that  it  can  scarcely 
be  doubted,  that  an  impression  made  upon  the  mucous  surface  of  the  oesophagus, 
conveyed  by  the  afferent  fibres  of  these  nerves  to  their  ganglionic  centre,  and 
reflected  downwards  along  the  motor  fibres,  is  the  real  cause  of  the  muscular  con- 
traction.    If  the  Pneumogastric  be  divided  in  the  rabbit,  on  each  side,  above  the 
oesophageal  plexus,  but  below  the  pharyngeal  branches,  and  the  animal  be  then 
fed,  it  is  found  that  the  food  is  delayed  in  the  oesophagus,  which  becomes  greatly 
distended.     Further,  if  the  lower  extremity  of  the  Pneumogastric  be  irritated, 
distinct  contractions  are  seen  in  the  oesophageal  tube,  proceeding  from  above 
downwards,  and  extending  over  the  cardiac  extremity  of  the  stomach. — We  have 
here,  then,  a  distinct  case  of  reflex  action  without  sensation,  occurring  as  one  of 
the  regular  associated  movements  in  the  natural  condition  of  the  animal  body ; 
and  it  is  very  interesting  to  find  this  following  upon  a  reflex  action  with  sensa- 
tion (that  of  the  pharynx),  and  preceding  a  movement  which  is  altogether  uncon- 
nected with  the  Spinal  Cord  (that  of  the  lower  part  of  the  alimentary  canal). 
The  use  of  sensation  in  the  former  case  has  been  already  shown  (§  424).     The 
muscular  fibres  of  the  oesophagus  are  also  excitable,  though  usually  in  a  less 
degree,  by  direct  stimulation ;  for  it  appears  that,  in  some  animals  (the  Dog,  for 
example),  section  of  the  pneumogastric  does  not  produce  that  check  to  the  pro- 
pulsion of  the  food,  which  it  occasions  in  the  Rabbit ;  and  .even  in  the  Rabbit, 
as  Dr.  M.  Hall  has  remarked,1  the  simple  contractility  of  the  muscular  fibre  occa- 
sions a  distinct  peristaltic  movement  along  the  tube,  after  its  nerves  have  been 
divided  ;  causing  it  to  discharge  its  contents,  when  cut  across.     Such  a  movement, 
indeed,  seems  to  take  place  in  something  of  a  rhythmical  manner  (that  is,  at  short 
and  tolerably  regular  intervals),  whilst  a  meal  is  being  swallowed;  but,  as  the 
stomach  becomes  full,  the  intervals  are  longer,  and  the  wave-like  contractions 
less  frequent. — That  the  action  of  the  Cardiac  sphincters  is  reflex,  and  is  depend- 
ent upon  the  "  nervous  circle"  furnished  by  the  Pneumogastric  nerves  and  their 
ganglionic  centres,  would  appear  from  the  fact  that,  when  the  trunks  of  these 
nerves  are  divided,  the  sphincter  no  longer  contracts,  and  the  food  regurgitates 
into  the  oesophagus.     The  re-opening  of  the  cardiac  orifices,  on  pressure  from 
within  (which  is  usually  resisted  by  the  sphincter,  as  in  the  acts  of  defecation, 
parturition,  &c.),  is  one  of  the  first  of  that  series  of  reversed  actions  which  con- 
stitutes the  .act  of   Vomiting  (§  431);  and  this  is  accompanied  by  a  reversed 
peristaltic  action  of  the  oesophagus.     The  independence  of  these  actions,  one  of 
another,  and  their  relation  to  a  common  cause,  are  remarkably  shown  by  the  fact 
that  when  vomiting  takes  place  as  a  consequence  of  the  injection  of  tartar  emetic 
into  the  veins,  the  reversed  peristaltic  action  of  the  oesophagus  is  performed  even 
after  its  separation  from  the  stomach. 

429.  The  food,  which,  thus  propelled  along  the  oesophagus,  enters  the  Stomach 
through  its  cardiac  orifice  in  successive  waves,  is  immediately  subjected  to  a 
peculiar  peristaltic  movement,  which  has  for  its  object  to  produce  the  thorough 
intermixture  of  the  gastric  fluid  with  the  alimentary  mass,  and  to  separate  the 
portion  which  has  been  sufficiently  reduced,  from  the  remainder.  The  fasciculi  com- 
posing the  muscular  wall  of  the  human  stomach  are  so  disposed  as  to  lessen  its 
diameter  in  every  direction  ;  and  whilst  the  cavity  is  empty,  they  are  uniformly 

1  "  Third  Memoir  on  the  Nervous  System,"  $  201. 


MOVEMENTS   OP   THE   ALIMENTARY   CANAL. — DEGLUTITION.      405 

contracted,  so  as  to  reduce  the  organ  to  its  smallest  dimensions.  When  food  is 
introduced,  the  contraction  of  the  parietes  as  a  whole  still  continues  to  such  a 
degree  as  to  make  them  closely  apply  themselves  to  its  surface  ;  but  the  contrac- 
tion of  the  individual  fasciculi  alternates  with  relaxation,  in  such  a  manner  as 


Fig.  118. 


A  front  view  of  the  Stomach,  distended  hy  flatus,  with  the  Peritoneal  Coat  turned  off;  1,  anterior  face  of  the 
oesophagus ;  2,  the  cul-de-sac,  or  greater  extremity ;  3,  the  lesser  or  pyloric  extremity ;  4,  the  duodenum ;  5,  5, 
a  portion  of  the  peritoneal  coat  turned  back ;  6,  a  portion  of  the  longitudinal  fibres  of  the  muscular  coat ;  7, 
the  circular  fibres  of  the  muscular  coat ;  8,  the  oblique  muscular  fibres,  or  muscle  of  Gavard ;  9,  a  portion  of 
the  muscular  coat  of  the  duodenum,  where  its  peritoneal  coat  has  been  removed. 

to  induce  a  great  variety  of  motions  in  this  organ,  sometimes  transversely,  and 
at  other  times  longitudinally.     "  These  motions/'  remarks  Dr.  Beaumont,  who 

Fig.  119. 


A  view  of  the  interior  of  the  Stomach,  as  given  by  the  removal  of  its  anterior  parietes ;  1,  oesophagus ;  2, 
cardiac  orifice  of  the  stomach ;  3,  its  greater  extremity,  or  cul-de-sac ;  4,  the  greater  curvature ;  5,  line  of  the 
attachment  of  the  omentum  majus ;  6,  the  muscular  coat ;  7,  the  anterior  cut  edge  of  the  mucous  coat;  8,  the 
rugas  of  the  mucous  coat;  9,  the  lesser  curvature ;  10,  the  beginning  of  the  duodenum;  11,  pyloric  orifice, 
or  valve  ;  12,  the  first  turn  of  the  duodenum  downwards. 

has  enjoyed  a  peculiar  opportunity  of  observing  them,1  "not  only  produce  a 
constant  disturbance  or  churning  of  the  contents  of  the  stomach,  but  they 

1  See  the  "  Case  of  Alexis  St.  Martin,  with  Observations  and  Experiments  by  Dr.  Beau- 
mont," republished  in  this  country  by  Dr.  Andrew  Combe. — This  patient  had  a  large  fistu- 
lous  orifice  in  his  stomach,  remaining  after  a  wound  which  had  laid  open  the  cavity ;  but 
his  general  health  had  been  completely  restored. 


406  OF   FOOD,    AND   THE  DIGESTIVE   PROCESS. 

compel  them,  at  the  same  time,  to  revolve  about  the  interior  from  point  to 
point,  and  from  one  extremity  to  the  other."  In  addition  to  these  movements, 
there  is  a  constant  agitation  of  the  stomach,  produced  by  the  respiratory  muscles. 


Fie.  120. 


A  Tiew  of  the  interior  of  the  Stomach  and  Duodenum  in  situ,  the  inferior  portion  of  each  having  been  re- 
moved :  1, 1,  the  under  side  of  the  liver ;  2,  the  gall-bladder ;  3,  3,  the  lesser  curvature  and  anterior  faces,  as 
seen  from  below  ;  4,  the  rugae,  about  the  cardiac  orifice ;  5,  the  pyloric  orifice ;  6,  the  rugae,  and  thickness  of 
this  orifice;  7,  7,  the  duodenum;  8,  lower  end  of  the  right  kidney. 

The  motions  of  the  stomach  itself  are  not  performed  on  any  very  exact  plan,  and 
are  much  influenced  by  the  character  of  the  ingesta,  the  state  of  the  general  system, 
and  by  other  circumstances.  The  following  is  the  ordinary  course,  however,  of 
the  revolutions  of  the  food.  "  After  passing  the  oesophageal  ring,  it  moves  from 
right  to  left,  along  the  small  arch  ;  thence  through  the  large  curvature,  from  left 
to  right.  The  bolus,  as  it  enters  the  cardia,  turns  to  the  left,  passes  the  aperture, 
descends  into  the  splenic  extremity,  and  follows  the  great  curvature  towards  the 
pyloric  end.  It  then  returns,  in  the  course  of  the  smaller  curvature,  makes  its 
appearance  again  at  the  aperture  in  its  descent  into  the  great  curvature,  to 
perform  similar  revolutions.  These  revolutions  are  completed  in  from  one  to 
three  minutes.  They  are  probably  induced,  in  a  great  measure,  by  the  circular 
or  transverse  muscles  of  the  stomach.  They  are  slower  at  first,  than  after  chy- 
myfication  has  considerably  advanced  ;"  at  which  time  also  there  is  an  increased 
impulse  towards  the  pylorus.  It  is  probable  that,  from  the  very  commencement 
of  chymification  until  the  organ  becomes  empty,  portions  of  chyme  are  continu- 
ally passing  into  the  duodenum ;  for  the  bulk  of  the  alimentary  mass  progressively 
diminishes,  and  this  the  more  rapidly  as  the  process  is  nearer  its  completion. 
The  accelerated  expulsion  appears  to  be  effected,  by  a  peculiar  action  of  the  trans- 
verse muscles;  and  especially  of  that  portion  of  them  which  surrounds  the 
stomach  at  about  four  inches  from  its  pyloric  extremity.  This  band  is  so  forcibly 
contracted  in  the  latter  part  of  the  digestive  process,  that  it  almost  separates  the 
two  portions  of  the  stomach  into  a  sort  of  hour-glass  form;  and  Dr.  B.  states 
that,  when  he  attempted  to  introduce  a  long  thermometer-tube  into  the  pyloric 
portion  of  the  stomach,  the  bulb  was  at  first  gently  resisted,  then  allowed  to  pass, 
and  then  grasped  by  the  muscular  parietes  beyond,  so  as  to  be  drawn  in;  whence 
it  is  evident  that  the  contraction  has  for  its  object,  to  resist  the  passage  of  solid 
bodies  into  the  pyloric  extremity  of  the  stomach,  at  this  stage  of  digestion,  whilst 
the  matter  which  has  been  reduced  to  the  fluid  form  is  pumped  away  (as  it  were) 
by  the  action  of  that  portion  of  the  viscus.  These  peculiar  motions  continue 
until  the  stomach  is  perfectly  empty,  and  not  a  particle  of  food  or  chyme  remains ; 
and  when  they  are  nearly  brought  to  a  close,  the  contraction  of  the  pyloric  orifice 
also  gives  way  to  an  extent  sufficient  to  allow  not  only  the  undigested  residue 
of  the  food,  but  also  large  solid  bodies  that  may  have  been  swallowed  (such  as 
coins  and  the  like),  to  pass  into  the  intestinal  canal. 


MOVEMENTS    OF   THE   STOMACH.  407 

430.  With  regard  to  the  degree  in  which  these  movements  of  the  Stomach, 
whose  share  in  the  Digestive  operation  is  so  important,  are  dependent  upon  the 
Spinal  cord,  and  are  consequently  of  a  "reflex"  nature,  it  is  difficult  to  speak 
with  certainty,  owing  to  the  contradictory  results  obtained  by  different  experi- 
menters.    These  contradictions,  however,  seem  partly  due  to  a  diversity  in  the 
nature  of  the  animals  experimented  on,  and  partly  to  a  difference  in  the  stage 
of  the  digestive  process  at  which  the  observations  were  made.    It  seems  to  be  well 
established,  by  the  researches  of  Reid,   Valentin,   and  others,1  that  distinct 
movements  may  be  excited  in  the  Stomach  of  the  Rabbit,  if  distended  with  food, 
by  irritating  the  Pneumogastric  soon  after  the  death  of  the  animal ;  these  move- 
ments seem  to  commence  from  the  cardiac  orifice,  and  then  to  spread  themselves 
in  a  sort  of  peristaltic  manner  along  the  walls  of  the  stomach ;   but  no  such 
movements  can  be  excited  if  the  stomach  be  empty.     Various  experiments  upon 
living  animals  have  led  to  a  similar  conclusion ;  food  taken  in  shortly  before  or 
subsequently  to  its  division,  having  been  found  to  be  only  dissolved  on  the  sur- 
face of  the  mass,  where  it  was  in  contact  with  the  mucous  membrane.     But  these 
experiments  have  been  made  for  the  most  part  upon  Herbivorous  animals,  such 
as  horses,  asses,  and  rabbits ;  whose  food  is  bulky  and  difficult  of  solution,  re- 
quiring to  be  constantly  changed  in  its  position,  so  that  every  part  of  it  may  be 
successively  brought  to  the  exterior.     On  the  other  hand,  Dr.  Reid  found,  in 
his  experiments  upon  Dogs,  that,  after  the  first  shock  of  the  operation  had  gone 
off,  solution  of  food  in  the  stomach,  and  absorption  of  chyle,  might  take  place; 
and  hence  it  may  be  inferred,  that  no  influence  of  this  nerve  upon  the  muscular 
parietes  of  the  stomach  is  essential  to  digestion  in  that  species.     This  conclusion 
harmonizes  well,  therefore,  with  the  fact  already  stated  respecting  the  absence 
of  such  influence  in  the  lower  parts  of  its  03sophagus ;  and  it  may,  perhaps,  be 
explained  by  the  consideration,  that  the  natural  food  of  the  dog  is  much  less 
bulky  and  more  easy  of  solution  than  that  of  the  animals  already  named  j  so 
that  there  is  not  so  much  need  of  that  peculiar  movement,  which  is  in  them  so 
important  an  aid  to  the  process  of  reduction. — There  is  yet  much  to  be  learned 
on  this  subject,  however;  especially  in  regard  to  the  degree  in  which  the  move- 
ments may  be  checked  or  altered,  by  impressions  transmitted  through  the  nerv- 
ous system.     It  was  stated  by  Brachet,  that,  in  some  of  his  experiments  upon 
the  Pneumogastric,  some  hours  after  section  of  the  nerve  on  both  sides,  the  sur- 
face only  of  the  alimentary  mass  was  found  to  have  undergone  solution,  the 
remainder  of  the  mass  remaining  in  the  condition  in  which  it  was  at  first  ingested ; 
and  if  this  statement  can  be  relied  on,  it  would  appear  that  the  movements  of 
the  stomach,  like  those  of  the  heart,  can  be  readily  affected  by  a  strong  nervous 
impression.     It  may  be  partly  in  this  manner,  therefore,  and  not  by  acting  upon 
the  secretions  alone,  that  strong  Emotions  influence  the  digestive  process,  as  they 
are  well  known  to  do.     On  the  other  hand,  the  moderate  excitement  of  plea- 
surable emotions  may  be  favorable  to  the  operation  \  not  only  by  giving  firmness 
and  regularity  to  the  action  of  the  heart,  and  thence  promoting  the  circulation 
of  the  blood,  and  the  increase  of  the  gastric  secretion ;  but  also  in  imparting 
firmness  and  regularity  to  the  muscular  contractions  of  the  stomach. 

431.  Much  discussion  has  taken  place  upon  the  question,  how  far  contraction 
of  the  parietes  of  the  Stomach  itself  actively  participates  in  the  operation  of 
Vomiting-  and  many  experiments  have  been  made  to  determine  the  facts  of  the 
case.     Some,  as  Magendie,  have  gone  so  far  as  to  affirm  that  the  stomach  is 
entirely  passive ;  grounding  this  inference  upon  the  fact  experimentally  ascer- 
tained, that  when  the  stomach  was  removed,  and  a  bladder  was  substituted  for 

1  See  Dr.  Reid's  "Physiological,  Anatomical,  and  Pathological  Researches,"  chap.  v. ; 
Valentin  "De  Functionibus  Nervorum  Cerebralium,"  &c.,  chap.  xi. ;  also  Longet,  "Anatomic 
et  Physiologic  du  Systeme  Nerveux,"  torn.  i.  p.  323  ;  and  Bischoff,  in  "Mviller's  Archiv.," 
1843. 


408  OF   FOOD,    AND   THE   DIGESTIVE   PROCESS. 

it,  this  was  emptied  of  its  contents,  by  the  compression  of  the  parietes  of  the 
abdomen,  when  tartar  emetic  was  injected  into  the  veins.  But  this  fact  by  no 
means  disproves  the  active  co-operation  of  the  stomach ;  and  judging  from  the 
analogy  of  the  uterus,  bladder,  and  rectum — whose  muscular  walls  are  all 
actively  concerned  in  the  expulsion  of  their  contents,  though  that  expulsion  is 
in  great  part  due  to  the  contraction  of  the  abdominal  muscles — we  should  be  led 
to  concur  with  the  common  opinion,  of  which  our  own  sensations  during  the  act 
would  indicate  the  correctness.  And  this  opinion  has  been  confirmed  by  observ- 
ation of  a  case,1  in  which  the  abdominal  parietes  having  been  accidentally  laid 
open  in  the  human  subject,  and  the  stomach  having  wholly  protruded  itself,  it  was 
seen  to  contract  itself  repeatedly  and  forcibly,  during  the  space  of  half  an  hour, 
until  by  its  own  efforts  it  had  expelled  all  its  contents  except  gases.  As  already 
mentioned,  the  relaxation  of  the  cardiac  sphincter  is  essential  to  the  act  of 
vomiting ;  and  unless  this  take  place,  all  the  other  movements  will  be  in  vain ; 
for  its  fibres,  when  contracted,  can  resist  the  combined  force  of  all  the  expulsor 
muscles.  There  can  be  little  doubt  that  the  violent  but  fruitless  efforts  at  vomit- 
ing which  we  occasionally  witness  (two  or  three  such  efforts  frequently  preceding 
the  effectual  one),  are  prevented  from  emptying  the  stomach  by  the  obstinacy  with 
which  the  cardiac  sphincter  is  kept  closed;  just  as  the  expiratory  effort  which 
assists  in  emptying  the  stomach,  is  prevented,  by  the  firmness  with  which  the 
glottis  is  held  shut,  from  expelling  the  contents  of  the  chest.  It  is  not  true,  as 
was  formerly  supposed,  that  the  diaphragm  actively  co-operates  in  the  effort  of 
vomiting ;  for,  as  was  first  pointed  out  by  Dr.  M.  Hall,2  this  effort,  like  those  of 
defecation,  urination,  and  parturition,  is  essentially  performed  by  the  muscles  of 
expiration ;  with  this  difference,  however,  that  the  diaphragm,  instead  of  being 
passive,  is  fixed,  and  supplies  a  firm  surface  against  which  the  stomach  is  pressed. 
In  this,  as  in  the  other  cases  just  referred  to,  the  expulsive  effort  is  preceded  by 
a  deep  inspiration,  after  which  the  glottis  is  spasmodically  closed  during  its  whole 
continuance. — The  immediate  causes  of  vomiting  may  be  reduced  to  three  dif- 
ferent categories :  1st.  The  contact  of  irritating  substances  with  the  mucous 
membrane  of  the  stomach  itself;  these,  however,  cannot  act  upon  more  than  its 
muscular  coat  by  direct  stimulation ;  and  their  operation  upon  the  associated 
muscles  must  take  place  by  reflexion,  through  the  "  nervous  circle"  furnished 
by  the  pneumogastrics  and  the  motor  nerves  of  expiration.  2d.  Irritations 
applied  to  other  parts  of  the  body,  likewise  operating  by  simply  reflex  transmis- 
sion ;  as  in  the  vomiting  which  is  consequent  upon  the  strangulation  of  a  hernia, 
or  the  passage  of  a  renal  calculus;  or  in  that  which  is  excited  by  the  injection  of 
tartar  emetic  or  emetin  into  the  circulating  current,  where  these  substances  pro- 
bably produce  their  characteristic  effect  by  their  operation  on  the  nervous  centres. 
3d.  Impressions  received  through  the  sensorial  centres,  which  may  be  either 
sensational  or  emotional,  but  which  do  not  operate  unless  they  are  felt.  In  this 
mode  seems  to  be  excited  the  vomiting  that  is  induced  by  tickling  the  fauces, 
which  first  gives  rise  to  the  sensation  of  nausea;  as  well  as  the  vomiting  conse- 
quent upon  disgusting  sights,  odors,  or  tastes,  and  upon  those  peculiar  internal 
sensations  which  are  preliminary  to  "  sea-sickness."  The  recollection  of  these 
sensations,  conjoined  with  the  emotional  state  which  they  originally  excited,  may 
itself  become  an  efficient  cause  of  the  action,  at  least  in  individuals  of  pecu- 
liarly irritable  stomachs  or  of  highly  sensitive  nervous  systems;  for  this  plays 
downwards  upon  the  sensorial  centres,  in  such  a  manner  as  to  excite  in  them 
the  same  condition,  as  that  which  was  originally  produced  through  the  medium 
of  the  sensory  nerve,  when  the  object  was  actually  present.  (See  CHAP.  xiv. 
SECT.  3.) 

1  Lepine  in  "Bullet,  de  1'Acad.  Roy.  de  Medecine,"  1844. 
8  "Quarterly  Journal  of  Science,"  vol.  xxv.  p.  388,  et  seq. 


MOVEMENTS   OF   THE    STOMACH.  409 

432.  The  passage  of  the  Chyme,  or  product  of  the  gastric  digestion,  through 
the  pyloric  orifice,  into  the  commencement  of  the  Intestinal  tube,  is  at  first  slow ; 
but  when  the  digestive  process  is  nearly  completed,  it  is  transmitted  in  much 
larger  quantities.  The  pyloric  orifice,  like  the  cardiac,  is  furnished  with  a 
sphincter  muscle ;  but  how  far  its  contractions  are  dependent  upon  "  reflex  ac- 
tion," has  not  yet  been  ascertained.  The  ingested  matter,  which  undergoes 
further  changes  of  a  very  important  character  within  this  portion  of  the  canal, 
is  gradually  propelled  onwards  by  the  peristaltic  contractions  of  its  walls;  and 
these  are  excited  by  the  contact,  either  of  the  products  of  digestion,  or  of  the 
secretions  poured  in  by  the  various  glands  that  discharge  their  products  into  the 
intestinal  tube.1  In  its  progress  along  the  small  intestines,  the  nutritious  por- 
tion of  the  ingested  matter  is  gradually  taken  up  by  the  bloodvessels  and  absorb- 
ents ;  and  the  residue,  combined  with  excrementitious  matters  separated  from 
the  blood,  begins  to  assume  the  faecal  character.  A  further  absorption  takes 
place  during  the  passage  of  the  faecal  matter  through  the  large  intestines;  and  thus, 
by  the  time  it  reaches  the  rectum,  it  has  acquired  a  considerable  degree  of  con- 
sistency.— The  ordinary  Peristaltic  movements  of  the  Intestinal  canal  are  fully 
accounted  for,  by  referring  them  to  the  contractility  of  the  muscular  portion  of 
its  walls,  called  into  action  by  direct  stimulation  (§  316) ;  and  that  they  are  not 
in  any  degree  dependent  upon  nervous  connection  with  the  Cerebro-spinal  centres, 
is  clearly  shown  by  their  continuance  after  the  destruction  of  these.  Some 
Physiologists  suppose  that  these  movements  are  attributable  to  "  reflex"  action, 
through  a  nervous  circle  furnished  by  the  fibres  and  ganglia  of  the  Sympathetic 
system.  This  supposition,  however,  is  entirely  unnecessary ;  since  the  Hallerian 
doctrine  of  independent  irritability,  of  the  truth  of  which  such  cogent  evidence 
has  been  adduced  (§§  325 — 327),  affords  an  adequate  explanation  of  them.  And 
it  will  be  found,  on  careful  examination,  to  have  no  sufficient  evidence  in  its  favor; 
the  utmost  which  experiment  can  show,  being  that  contractions  *ftiay  be  excited 
through  the  medium  of  the  Sympathetic  nerves.  But  the  experiments  of  Valen- 
tin, who,  more  than  any  other  Physiologist,  has  succeeded  in  obtaining  positive 
results  of  this  kind,  also  indicate  that  the  motor  influence  does  not  originate  in 
the  Sympathetic  ganglia,  but  is  derived  from  the  Spinal  cord.3  The  following 
are  his  general  results,  so  far  as  they  apply  to  this  part  of  the  subject. — The 
lower  part  of  the  (Esophagus  in  the  neck  is  made  to  contract  peristaltically  from 
above  downwards,  by  irritation  of  the  roots  of  the  first  three  cervical  Spinal 
nerves,  and  of  the  cervical  portion  of  the  Sympathetic,  through  which  last  the 
former  evidently  operate.  The  thoracic  portion  of  the  oesophagus  is  made  to 
contract,  by  irritation  of  the  lowest  Sympathetic  ganglion  of  the  neck,  and  of 
the  higher  thoracic  ganglia,  and  also  of  the  roots  of  the  lower  cervical  Spinal 
nerves. — Muscular  contractions  of  the  Stomach  are  produced,  by  irritation  of 
the  roots  of  the  4th,  5th,  6th,  and  7th  cervical  nerves,  and  of  the  first  thoracic 
in  the  rabbit ;  so  that  a  distinct  furrow  is  evident  between  the  cardiac  and  pyloric 
portion  of  the  viscus;  and  the  lower  the  nerve  is  irritated,  the  nearer  to  the  pylo- 
rus do  the  contractions  extend.  Irritation  of  the  first  thoracic  ganglion  of  the 
Sympathetic  produces  the  same  effect. — Contractions  of  the  Intestinal  tube, 
varying  in  place  according  to  the  part  of  the  Spinal  cord  experimented  on,  may 
be  excited  by  irritation  of  the  roots  of  the  dorsal,  lumbar,  and  sacral  nerves,  and 
of  the  trigeminus ;  and  similar  effects  are  produced  by  irritation  of  the  lower  part 
of  the  thoracic  portion,  of  the  lumbar,  and  of  the  sacral  portions  of  the  Sympa- 
thetic— also  of  the  splanchnic,  and  of  the  gastric  plexus. 

1  The  Bile  seems  to  have  an  important  share  in  producing  this  effect;  since,  when  the 
ductus  choledochus  is  tied,  constipation  always  occurs.     The  purgative  action  of  Mercurials 
seems  to  depend  in  great  part  upon  the  increase  of  the  hepatic  and  other  secretions  which 
it  induces. 

2  "De  Functionibus  Nervorum  Cerebralium  et  Nervi  Sympathetici,"  book  ii.  chap.  2. 


410  OP   FOOD,    AND   THE   DIGESTIVE   PROCESS. 

433.  From  these  facts  it  is  evident,  that  the  movements  of  the  Intestinal 
tube  may  be  influenced  by  the  Spinal  Cord ;  and  that  what  is  commonly  termed 
the  Sympathetic  nerve,  is  the  channel  of  that  influence,  by  the  fibres  which  it 
derives  from  the  Spinal  system.     But  it  by  no  means  thence  follows,  that  the 
ordinary  peristaltic  actions  of  the  muscles  in  question  are  dependent  on  a  stimu- 
lus reflected  through  the  spinal  cord,  rather  than  on  one  directly  applied  to  them- 
selves.    It  is  clear  that,  although  these  movements  are  of  the  first  importance 
to  the  welfare  of  the  system,  such  means  of  sustaining  them  are  feeble,  com- 
pared to  those  which  we  find  provided  for  the  maintenance  of  the  distinctly- 
reflex  actions  of  deglutition,  respiration,  &c.     And  the  fact  that  they  are  capable 
of  being  at  all  times  more  easily  excited  by  stimuli  applied  to  the  muscles,  than 
by  any  kind  of  irritation  applied  to  their  nerves — taken  in  connection  with  the 
fact  that  the  muscles  not  only  remain  irritable,  but  will  execute  regular  peri- 
staltic contractions,  for  a  long  time  after  any  such  contractions  can  be  excited 
through  their  nerves — seems  a  very  strong  indication  that  nervous  influence  is 
not  the  ordinary  agent  in  calling  these   movements  into  play.     On  the  other 
hand,  we  do  know  that  the  peristaltic  movements  are  affected  by  particular 
states  of  mind,  or  by  conditions  of  the  bodily  system;  and  the  connection  just 
traced  satisfactorily  accounts  for  this,  and  is  itself  sufficiently  explained.     The 
Intestinal  tube,  then,  from  the  stomach  to  the  rectum,  is  not  dependent  upon 
the  Nervous  Centres  either  for  its  contractility,  or  for  its  power  of  exercising  it, 
but  is  enabled  to  propel  its  contents  by  its  own  inherent  powers;  still  we  find 
that  here,  as  in  other  instances,  the  nervous  centres  exert  a  general  control  over 
even  the  Organic  functions,  doubtless  for  the  purpose  of  harmonizing  them  with 
each  other,  and  with  the  conditions  of  the  organs  of  Animal  life. 

434.  On  examining  the  outlet  by  which  the  faeces  are  voided,  we  find  that  it 
is  placed,  like  the  entrance,  under  the  guardianship  of  the  Spinal  Cord;  subject, 
however,  to  some  control  on  the  part  of  the  Will.     In  the  lowest  animals,  the 
act  of  discharging  excrementitious  matter  is  probably  as  involuntary  as  are  the 
acts  immediately  concerned  in  the  introduction  of  nutriment;  and  it  is  per- 
formed as  often  as  there  is  anything  to  be  got  rid  of.     In  the  higher  classes, 
however,  such  discharges  are  much  less  frequent;  and  reservoirs  are  provided, 
in  which  the  excrementitious  matter  may  accumulate  in  the  intervals.     The 
associated  movements  required  to  empty  these,  are  completely  involuntary  in 
their  character;  and  are  excited  by  the  quantity,  or  stimulating  quality,  of  the 
contents  of  the  reservoir.     But,  had  volition  no  control  over  them,  great  incon- 
veniences would  ensue;  hence  sensation  is  excited  by  the  same  stimulus  which 
produces  the  movements,  in  order  that,  by  arousing  the  will,  the  otherwise  in- 
voluntary motions  may  be  restrained  and  directed.     There  can  be  little  doubt, 
from  the  experiments  of  Dr.  M.  Hall,  as  well  as  from  other  considerations,  that 
the  associated  movements,  by  which  the  contents  of  the  rectum  (and  bladder) 
are  discharged,  correspond  much  with  those  of  Respiration ;  being  in  their  own 
nature  excito-motor,  but  being  capable  of  a  certain  degree  of  voluntary  restraint 
and  assistance.     The  act  of  Defecation  (as  of  Urination)  chiefly  depends  upon 
the  combined  contraction  of  the  abdominal  muscles,  similar  to  that  which  is 
concerned  in  the  expiratory  movement;  but  the  glottis  being  closed  so  as  to  pre- 
vent the  upward  motion  of  the  diaphragm,  their  force  acts  only  on  the  contents 
of  the  abdominal  cavity ;  and  so  long  as  the  sphincter  of  the  cardia  remains 
closed,  it  must  press  downwards  upon  the  walls  of  the  rectum  and  bladder — the 
contents  of  the  one  or  the  other  of  these  cavities,  or  of  both,  being  expelled, 
according  to  the  condition  of  their  respective  sphincters.     These  actions  are 
doubtless  resisted  by  the  contraction  of  the  walls  of  the  rectum  and  bladder 
themselves;  for  we  sometimes  find  their  agency  sufficient  to  expel  the  contents 
of  the  cavities,  when  there  is  a  total  paralysis  of  the  ordinary  expulsors,  pro- 
vided that  the  sphincters  be  at  the  same  time  sufficiently  relaxed.     This  is  more 


CHANGES   OF   FOOD   IN   THE   ALIMENTARY   CANAL.  411 

especially  the  case,  when  their  power  is  augmented  by  increased  nutrition.  For 
example,  in  many  cases  of  disease  or  injury  of  the  Spinal  Cord,  the  bladder 
ceases  to  expel  its  contents,  through  the  interruption  of  the  circle  of  reflex 
actions;  but  after  a  time,  the  necessity  for  drawing  off  the  urine  by  the  catheter 
is  found  to  exist  no  longer,  the  fluid  being  constantly  expelled  as  soon  as  it  has 
accumulated  in  small  quantities.  In  such  cases,  the  mucous  coat  is  found  after 
death  to  be  thickened  and  inflamed;  and  the  muscular  coat  to  be  greatly  in- 
creased in  strength,  and  contracted  upon  itself.  It  would  seem,  then,  that  the 
abnormal  irritability  of  the  mucous  membrane,  and  the  increased  nutrition  of 
the  muscular  substance  which  appears  consequent  upon  it,  enable  the  latter  to 
expel  the  urine  without  the  assistance  of  the  ordinary  expulsors. 

435.  On  the  other  hand,  the  sphincters  which  antagonize  the  expellent  action, 
are  usually  maintained  in  a  state  of  moderate  contraction,  so  as  to  afford  a  con- 
stant check  to  the  egress  of  the  contents  of  the  cavities;  and  this  condition  has 
been  fully  proved  by  Dr.  M.  Hall,  to  result  from  their  connection  with  the 
Spinal  Cord,  ceasing  completely  when  this  is  interrupted.     But  the  sphincters 
are  certainly  in  part  controlled  by  the  will,  and  are  made  to  act  in  obedience  to 
the  warning  given  by  sensation;  and  this  voluntary  power  is  frequently  destroyed 
by  injuries  of  the  Brain,  whilst  the  Spinal  Cord  remains  able  to  perform  all  its 
own  functions,  so  that  discharge  of  the  urine  and  faeces  occurs.    In  their  moderate 
action,  the  expulsors  and  the  sphincters  may  be  regarded  as  balancing  one 
another,  so  far  as  their  reflex  action  is  concerned;  the  latter  having  rather  the 
predominance,  so  as  to  restrain  the  operation  of  the  former.     But,  when  the 
quantity  or  quality  of  the  contents  of  the  cavity  gives  an  excessive  stimulus  to 
the  former,  their  action  predominates,  unless  the  will  be  put  in  force  to  strengthen 
the  resistance  of  the  sphincter;  this  we  are  frequently  experiencing,  sometimes 
to  our  great  discomfort.     On  the  other  hand,  if  the  stimulus  be  deficient,  the 
will  must  aid  the  expulsors,  in  order  to  overcome  that  resistance  which  is  due 
to  the  reflex  contraction  of  the  sphincters;  of  this  also  we  may  convince  our- 
selves, when  a  sense  of  propriety,  or  a  prospective  regard  to  convenience,  occa- 
sions us  to  evacuate  the  contents  of  the  rectum  or  bladder  without  a  natural 
call  to  do  so. 

4.    Of  the   Changes  which  the  Food  undergoes,  during  its  passage  along  the 

Alimentary  Canal. 

436.  The  object  of  the  Digestive  process,  as  already  pointed  out,  is  to  reduce 
the  Alimentary  matters  to  a  condition  in  which  they  can  be  introduced  by 
Absorption  into  the  Circulating  system.    This  reduc- 
tion is  partly  effected,  as  we  have  seen,  by  Mechanical  Fig.  121. 
means ;  but  it  is  chiefly  due  to  the  chemical  agencies 

which  are  brought  to  bear  upon  the  ingested  sub- 
stances during  their  transit  through  the  mouth,  the 
stomach,  and  the  upper  portion  of  the  intestinal 
tube.  The  first  of  these  is  exerted  by  the  Salivary 
fluid,  which  is  incorporated  with  the  food  in  the  act 
of  mastication,  and  of  which  a  large  quantity  de- 
scends with  it  to  the  stomach.  For  the  secretion  of 
this  fluid,  it  will  be  remembered  that  three  pairs  of 
glands  of  considerable  size  are  provided;  namely,  the 
parotid,  the  sublingual,  and  the  submaxillary.  But 
in  addition  to  these,  a  very  important  part  of  the 
fluid  is  furnished  by  the  numerous  follicular  glands 
lodged  in  and  beneath  the  buccal  mucous  membrane.  L°^ule  of  Par°m  Gland  of  a 

rru       a   r  i       j  new-born    Infant,  injected    with 

The  Salivary  glands  are  constructed  upon  that  folh-    mercury.  Magnified  50  diameters. 


412 


OF   FOOD,    AND   THE   DIGESTIVE   PROCESS. 


cular  type  of  which  an  example  has  been  already  given  from  the  glands  of 
Brunner  (§  234);  their  ultimate  follicles  (Fig.  29)  are  very  minute  (their 
average  diameter  being  only  about  l-1200th  of  an  inch),  and  are  closely  sur- 
rounded by  a  plexus  of  capillary  bloodvessels  (Fig.  28).  Their  development 
commences  from  a  simple  canal,  sending  off  bud-like  processes,  which  open 
from  the  mouth,  and  lie  amidst  a  cellular  blastema;  and  as  their  evolution 
advances,  the  large  parent-cells  of  this  blastema  form  communications  with 
the  gland-canal,  which  is  at  the  same  time  extending  its  ramifications,  and  re- 
main as  the  terminal  follicles  of  these. 

437.  The  inquiry  into  the  chemical  constitution  and  properties  of  the  Saliva 
has  for  the  most  part  been  limited  to  the  fluid  obtained  from  the  mouth,  rather 
than  to  that  secreted  by  the  glands.  The  specific  gravity  of  this  fluid  is  usually 
(according  to  Lehmann)  from  1004  to  1006;  but  it  may  rise  to  1008  or  1009, 
or  may  sink  to  1002,  without  any  indication  of  co-existing  disease.  When  ex- 
amined microscopically,  the  Saliva  is  found  to  contain  a  small  number  of  minute 
corpuscles  derived  from  the  Salivary  glands,  and  large  epithelial  scales  thrown 
off  by  the  buccal  mucous  membrane.  Its  reaction  is  usually  alkaline,  that  of 
the  Saliva  furnished  by  the  principal  glands  being  always  so  (in  the  state  of 
health),  whilst  that  of  the  buccal  mucous  membrane  is  acid;  so  that  when  the 
former  predominates,  as  is  always  the  case  when  food  is  being  masticated  and 
digested,  the  saliva  of  the  mouth  is  alkaline ;  whilst,  when  the  latter  is  more 
abundant,  as  is  often  the  case  during  the  intervals  of  digestion,  from  the  slow 
rate  at  which  the  salivary  glandules  then  pour  forth  their  product,  the  buccal 
saliva  is  frequently  acid. — The  following  are  two  of  the  most  recent  analyses  of 
this  fluid  that  have  been  made;  the  one  by  the  eminent  chemist  Frerichs,1  whose 
contributions  to  the  Physiology  of  Digestion  are  among  the  most  valuable  of  the 
results  which  have  been  furnished  by  recent  inquiries  in  this  direction ;  and  the 
other  by  Dr.  Wright,9  who  has  made  a  special  study  of  the  Salivary  secretion. 


Dr.  Wright. 


Dr.  Frerichs. 


Water 

Solid  Matters 


Ptyalin       . 

Mucus  (and  epithelium) 

Fatty  matter 

Albumen  (with  soda) 

Sulphocyanide  of  potassium 

Alkaline  and  earthy  salts 

Loss 


988.10 

Water 

11.90 

Solid  Matters     . 

1.80 

Ptyalin      .         .         .      ' 

2.60 

Mucus  and  epithelium 

.50 

Fatty  matter 

1.70 

Sulphocyanide  of  potassiun 

i 

.90 

Alkaline  and  1    f  chlorides 

~] 

3.20 

earthy        /  \  phosphate 

s 

1.20 

Oxide  of  iron 

J 

100.00 

994.10 
5.90 

1.41 

2.13 
.07 
.10 

2.19 


100.00 

The  total  proportion  of  solid  matter,  as  the  preceding  analyses  show,  is  subject 
to  great  variation;  it  seems  commonly  to  range  between  7  and  12  parts  in  1000; 
but  may  even  reach  16  parts.  We  shall  presently  see,  however,  that  this  varia- 
tion may  be  partly  attributed  to  a  difference  in  the  proportions  of  the  fluid 
poured  into  the  mouth  by  the  several  glands  which  secrete  it.  The  substance 
to  which  the  designation  of  Ptyalin  is  given  is  that  on  whose  presence  the  pecu- 
liar properties  of  the  Saliva  appear  to  depend;  and  it  appears,  as  regards  its 
chemical  nature,  to  be  an  albuminous  compound,  in  such  a  state  of  change,  how- 
ever, that  it  acts  the  part  of  a  "  ferment."3 — The  presence  of  sulpho-cyanogen 

1  See  "Canstatt's  Jahresbericht,"  1850,  p.  136;  and  "Wagner's  Handwurterbuch," 
art.  "Verdauung." 

2  "Lancet,"  March,  1842. 

3  The  following,  according  to  Prof.  Lehmann  ("Lehrbuch  der  physiologischen  Che- 
mie,"  band  ii.),  are  the  distinctive  chemical  characters  of  ptyalin.     Being  held  in  solu- 


CHANGES    OF   FOOD   IN    THE   ALIMENTARY   CANAL.  413 

is  interesting,  not  only  because  this  is  the  only  animal  product  in  which  this 
substance  is  known  to  occur,  but  because  the  uniformity  with  which  it  makes 
its  appearance  when  searched  for,  would  seem  to  indicate  that  it  performs  some 
peculiar  part  in  the  operations  to  which  the  salivary  fluid  is  subservient.  More- 
over, in  a  medico-legal  point  of  view,  the  existence  of  a  sulphocyanide  in  the 
saliva  has  a  special  importance ;  since,  if  in  a  state  of  sufficient  concentration,  it 
causes  the  saliva  to  exhibit  the  same  blood-red  color,  when  treated  with  a  per- 
salt  of  iron,  as  that  which  is  produced  by  meconic  acid.  (The  difference  be- 
tween the  two,  however,  is  easily  made  apparent,  by  adding  a  solution  of  per- 
chloride  of  mercury;  for  this  causes  the  color  produced  by  the  sulphocyanide 
to  disappear,  whilst  it  has  no  action  on  that  which  is  due  to  the  presence  of 
meconic  acid.)  The  Salts  of  the  Saliva,  with  the  exception  of  the  foregoing, 
seem  to  correspond  closely  with  those  of  the  blood;  and  its  alkaline  reaction 
appears  due,  not  to  the  presence  of  a  free  alkali,  but  to  that  of  the  basic  phos- 
phate of  soda.  The  "  tartar"  which  collects  on  the  teeth  consists  principally  of 
the  earthy  phosphates,  which  are  held  together  by  about  20  per  cent,  of  animal 
matter;  and  the  same  may  be  said  of  the  salivary  concretions  which  occasionally 
obstruct  the  ducts. 

438.  From  the  experiments  of  MM.  Magendie1  and  Cl.  Bernard,3  however, 
on  the  secretions  of  the  respective  glands,  as  obtained  directly  from  them- 
selves by  tubes  passed  into  their  ducts,  it  appears  that  their  composition  and 
physical  characters  are  by  no  means  uniform.  For  the  fluid  of  the  parotid  and 
sublingual  glands  is  clear,  and  as  limpid  and  thin  as  water,  and  contains  but  a 
small  proportion  of  solid  matters  (not  more  than  0.47  per  cent,  in  the  dog,  and 
0.76  per  cent,  in  the  horse,  according  to  Lehmann  and  Jacubowitsch) ;  whilst  the 
fluid  of  the  submaxillary  is  thick  and  viscid,  resembling  in  color  and  consistence 
ordinary  simple  syrup,  and  containing  a  far  larger  amount  of  solid  matters,  in 
which  the  organic  components,  however,  bear  a  smaller  proportion  to  the  salts, 
than  they  do  in  the  fluid  of  the  other  two  glands.  Now  it  has  been  observed  by 
Bernard,  that  the  flow  of  saliva  which  takes  place  during  mastication  proceeds 
almost  entirely  from  the  parotid  and  sublingual  glands;  whilst,  during  the  act  of 
deglutition,  when  the  tongue  carries  the  bolus  back  into  the  pharynx,  the  secre- 
tion of  the  submaxillary  is  the  greatest.  Hence  it  seems  reasonable  to  conclude, 
that  the  purpose  of  these  secretions  is  not  identical;  that  of  the  parotid  and  sub- 
lingual  being  to  saturate  the  food  when  mixed  up  with  it  in  the  act  of  mastica- 
tion ;  whilst  that  of  the  submaxillary  seems  rather  destined  to  facilitate  degluti- 
tion.3 The  fluid  which  is  secreted  by  the  three  principal  glands,  moreover,  appears 
(from  the  experiments  of  Magendie  and  Bernard)  to  be  far  less  efficacious  than 
is  the  buccal  saliva,  in  producing  that  chemical  change  in  the  food  which  it  is 
the  peculiar  attribute  of  this  secretion  to  exert  (§  439) ;  whence  it  seems  fair  to 

tion  by  an  alkali,  the  addition  of  a  little  acetic  acid  occasions  a  flocculent  precipitate, 
wliich  readily  dissolves  in  an  excess  of  the  acid.  When  boiled  with  hydrochlorate  of  am- 
monia or  sulphate  of  magnesia,  the  alkaline  solution  of  ptyalki  becomes  very  turbid ;  it  is 
precipitated  by  tannic  acid,  bichloride  of  mercury,  and  basic  acetate  of  lead ;  but  not  by 
alum,  sulphate  of  copper,  &c.  The  acetic  acid  solution  is  strongly  precipitated  on  the 
addition  of  ferrocyanide  of  potassium ;  and  when  boiled  with  nitric  acid,  it  yields  a  yellow 
solution.  By  these  reactions  it  is  shown  that  ptyalin  closely  resembles  both  albumen  and 
casein,  without  being  identical  with  either  of  them. 

1  "Rapport  lu  dans  la  seance  de  1'Institut,"  Oct.  25,  1845. 

2  "Archives  Generates  de  Medecine,"  4ieme  serie,  torn.  xiii. 

3  This  idea  of  M.  Bernard's  was  confirmed  by  the  following  experiments.     He  made  an 
opening  into  the  oesophagus  of  a  horse,  from  which  he  drew  the  alimentary  bolus  as  it 
descended ;  and  on  weighing  it,  he  found  that  by  the  imbibition  of  saliva  it  had  increased 
elevenfold.     He  next  tied  Wharton's  duct,  and  found  that  the  animal  required  41  minutes 
to  masticate  what  had  previously  required  only  9  minutes ;  and  the  mass,  when  withdrawn 
from  the  oesophagus,  was  covered  with  mucus  and  a  glutinous  fluid,  the  interior  being  dry 
and  friable,  and  the  whole  increased  in  weight  only  three  and  a  half  times. 


414  OP   FOOD,   AND   THE   DIGESTIVE   PROCESS. 

conclude  that  the  "  ferment"  to  which  this  change  is  due  is  chiefly  furnished 
by  the  smaller  buccal  glandulae.  Of  the  quantity  of  Saliva  which  is  secreted 
daily,  it  is  impossible  to  form  an  exact  estimate,  since  it  varies  greatly  with  the 
character  of  the  food  ingested,  and  the  frequency  with  which  that  food  is  taken ; 
the  secreting  process  being,  indeed,  almost  suspended  when  the  masticator 
muscles  and  tongue  are  completely  at  rest,  unless  excited  by  a  nervous  stimulus. 
The  taste,  the  sight,  or  even  the  idea,  of  savory  food,  is  sufficient  to  cause  a 
flow  of  saliva,  especially  after  a  long  fast;  but  it  is  by  the  masticatory  move- 
ments that  this  flow  is  chiefly  promoted ;  so  that  the  amount  poured  forth  will 
in  a  great  degree  depend  upon  the  duration  of  these  movements — this,  again, 
being  governed  by  the  degree  in  which  the  food  requires  mechanical  reduction. 
It  seems  probable  that  the  average  in  Man  is  between  15  and  20  ounces  daily. 

439.  There  can  be  little  doubt  that  the  most  important  action  of  the  Saliva 
upon  the  food,  is  in  preparing  it  for  chemical  operations  to  which  it  is  to  be 
afterwards  subjected,  by  promoting  its  mechanical  reduction  in  the  act  of  masti- 
cation, and  by  facilitating  the  subsequent  admixture   of  other  watery  fluids, 
through  the  intimacy  with  which  it  is  incorporated  with  the  alimentary  matter. 
Its  peculiar  physical  qualities  give  it  a  remarkable  adaptation  for  this  purpose; 
for  water  could  not  be  so  easily  or  completely  incorporated.     But  there  can  be 
no  doubt  that  the  peculiar  organic  constituent  of  the  saliva  has  a  chemical 
action  upon  the  farinaceous  elements  of  food ;  for  it  has  been  experimentally 
proved  to  have  the  power  of  converting  starch  or  dextrin  into  grape-sugar. 
This  power  is  not  peculiar,  however,  to  the  Saliva;  for  M.  Bernard  has  shown 
that  many  azotized  substances,  in  a  state  of  incipient  decomposition,  exert  a 
similar  agency ;  still  it  appears  to  be  possessed  by  ptyalin  in  a  much  greater 
degree  than  by  any  of  these.     But  as  the  transformation,  at  the  usual  tempera- 
ture of  the  body,  is  not  effected  with  great  rapidity,  no  very  great  amount  of 
sugar  can  be  thus  generated,  previously  to  the  entrance  of  the  food  into  the 
stomach.    There,  however,  the  transforming  process  may  continue;  for,  although 
it  has  been  usually  stated  that  an  alkaline  condition  of  the  fluid  is  necessary  for 
the  operation  of  this  "  ferment,"  yet  it  has  been  shown  by  Frerichs,  and  con- 
firmed by  Dr.  Bence  Jones,1  that  this  action  continues  in  the  stomach,  notwith- 
standing the  acid  condition  which  the  Salivary  fluid  then  acquires  from  admix- 
ture with  the  gastric  fluid.     No  satisfactory  evidence  has  yet  been  obtained, 
that  the  Saliva  has  any  chemical  action  upon  azotized  substances;  and,  conse- 
quently, as  regards  these  constituents  of  the  food,  its  operation  must  be  con- 
sidered as  purely  physical.     We  shall  find  that  a  different  secretion  is  provided 
for  their  transformation,  which  has  no  action  upon  farinaceous  matter.3 

440.  On  its  entrance  into  the  Stomach,  the  food  is  subjected  to  the  operation 
of  the  Gastric  Juice,  which  is  secreted  by  the  follicles  in  its  walls,  or  by  a 
certain  part  of  them.     This  follicular  apparatus  is  extremely  extensive,  and 
makes  up  the  chief  part  of  the  thickness  of  the  gastric  mucous  membrane.     If 
this  be  divided  by  a  section  perpendicular  to  the  surface,  it  is  seen  to  be 

1  "Medical  Times,"  May  31  and  June  14,  1851. 

2  An  excellent  summary  of  the  present  state  of  our  knowledge  of  the  characters  and 
offices  of  the  saliva  is  given  by  Dr.  Bence  Jones  in  the  "  Medical  Times"  for  May  31, 
1851.     A  summary  of  M.  Bernard's  researches  on  this  subject  will  be  found  in  the  "  Amer. 
Journ.  of  Med.  ScL,"  Oct.  1851.     The  Second  Volume  of  Prof.  Lehmann's  Physiological 
Chemistry  also  contains  a  large  amount  of  information  on  this  subject.     Among  the  most 
important  special  contributions  to  the  chemical  and  physiological  history  of  the  Saliva, 
not  previously  referred  to,  are  those  of  Leuchs,  by  whom  the  discovery  of  its  power  of 
transforming  starch  into  sugar  was  first  made  ("Kastner's  Archiv.,"  1831,  quoted  in 
Muller?s  "Elements  of  Physiology,"  p.  577),  Mialhe  ("Memoire  sur  la  digestion  et  1'assi- 
milation  des  matieres  amyloides  et  sucr£es,"  1846),  Jacubowitsch  ("De  Saliva,"  diss. 
inaug.  Dorpati  Livon.,  1848),  and  Tilanus  ("De  Saliva  et  Muco,"  diss.  inaug.,  Amstelod., 
1849). 


CHANGES   Or   FOOD   IN   THE   ALIMENTARY   CANAL. 


41.5 


almost  entirely  composed  of  a  multitude  of  parallel  tubuli  closely  applied  to 
each  other,  their  caecal  extremities  abutting  against  the  submucous  tissue,  and 
their  open  ends  being  directed  towards  the  cavity  of  the  stomach.  The  con- 
formation of  these  tubuli  is  not  the  same,  however,  in  every  part;  for  whilst 
they  are  usually  straight  and  simple,  especially  in  the  cardiac  portion  of  the 
stomach,  they  are  longer  and  more  complicated  in  the  neighborhood  of  the 
pylorus,  their  deeper  parts  presenting  a  sacculated  or  somewhat  convoluted 
appearance  (Fig.  122).  Between  the  tubuli,  bloodvessels  pass  up  from  the  sub- 
mucous  tissue,  and  form  a  vascular  network  on  its  surface,  in  the  interspaces 
of  which  the  orifices  of  the  tubes  are  seen  (Fig.  126).  From  the  examination 


Fig.  122. 


Section  of  the  Mucous 
Membrane  of  the  Stomach, 
near  the  pylorus,  showing 
the  Gastric  Follicles:  1, 
magnified  3  times ;  2,  mag- 
nified 20  times. 


Fig.  123. 


A.  Horizontal  section  of  a  stomach-cell,  a  little 
way  within  its  orifice,    a.  Basement  membrane,    b. 
Columnar  epithelium.    All  but  the  centre  of  the 
cavity  of  the  cell  is  occupied  by  transparent  mucus, 
which  seems  to  have  oozed  from  the  open  extremi- 
ties of  the  epithelial  particles,    c.  Fibrous  matrix 
surrounding  and  supporting  the  basement  mem- 
brane,   d.  Small  bloodvessel. 

B.  Horizontal  section  of  a  set  of  stomach  tubes 
proceeding  from  a  single  cell.    The  letters  refer  to 
corresponding  parts.    The  epithelium  is  glandular ; 
the  nuclei  very  delicate ;  the  cavity  of  the  tubes 
very  small,  and  in  some  cases  not  visible. 

From  the  dog,  after  twelve  hours'  fasting.    Mag- 
nified 200  diameters. 

of  horizontal  sections  of  the  Mucous  membrane  at  different  depths,  Dr.  Todd 
has  ascertained  that  the  tubuli  are  arranged  in  bundles  or  groups,  surrounded 
and  bound  together  by  areolar  tissue;  the  size  of  the  bundles,  however,  and  the 
number  of  tubules  contained  in  them,  vary  considerably.  The  character  of  the 
internal  surface  of  the  stomach,  and  the  mode  in  which  the  tubuli  open  upon  it, 
are  by  no  means  the  same  in  different  parts  of  the  organ.  When  a  well-injected 
preparation  is  examined  with  the  microscope,  it  is  seen  that  on  the  convex  sur- 


416 


OF  FOOD,  AND  THE  DIGESTIVE  PROCESS. 


Fig.  124. 


faces  of  the  rugae  the  orifices  of  the  follicles  lie  singly  in  the  interspaces  of  the 
capillary  network  (Fig.  126,  A).  But  a  large  proportion  of  the  surface  exhibits 
a  sort  of  honeycomb  appearance,  being  divided  by  partition-like  elevations  into 

pits  which  are  more  or  less  circular  or  hex- 
agonal in  form,  their  usual  diameter  being 
from  100th  to  1-2 50th  of  an  inch,  and  their 
depth  variable ;  in  the  bottom  of  each  of 
these  pits,  from  three  to  five  (and  some- 
times more)  orifices  of  the  gastric  follicles 
may  be  seen  (Fig.  125).  The  ridges  which 
divide  these  pits  or  alveoli  are  highly  vas- 
cular ;  and  the  orifices  of  the  follicles  lie, 
as  before,  in  the  interspaces  of  a  capillary 
network  which  covers  the  floor  of  each  de- 
pression. As  we  pass  towards  the  pyloric 
portion  of  the  stomach,  however,  the  ridges 
which  divide  the  alveoli  become  more  and 
more  elevated,  and  present  conical  elonga- 
tions at  certain  points;  and  these  elonga- 
tions become  more  and  more  marked,  until, 

Fig.  125. 


Vertical  section  of  a  stomach  cell,  with  its 
tubes :  A  in  the  middle  region,  B  in  the  pyloric 
region,  a  a.  Orifices  of  the  cells  on  the  inner 
surface  of  the  stomach,  b  b.  Different  depths  at 
which  the  columnar  epithelium  is  exchanged 
for  glandular,  c.  Pyloric  tube,  or  prolonged 
stomach  cell.  d.  Pyloric  tubes,  terminating 
variously,  and  lined  to  their  extremities  with 
sub-columnar  epithelium. 

From  the  dog,  after  twelve  hours'  fasting. 
Magnified  200  diameters. 


Portion  of  the  Mucous  Membrane  of  the  Stomach,  show- 
ing entrances  to  the  gastric  follicles  in  pits  upon  its  surface. 


in  the  neighborhood  of  the  pyloric  orifice, 
they  assume  the  form  and  appearance  of 
the  villi  of  the  small  intestine  (Fig.  126, 
B),  being,  however,  of  much  smaller  size, 
and  destitute  of  the  lacteal  absorbents  which 
give  to  the  latter  their  distinctive  charac- 
ter.1— Of  the  contents  of  the  gastric  folli- 
cles, an  account  has  been  already  given 
(§  235);  from  which  it  is  obvious  that  here,  as  elsewhere,  the  peculiar  product 
which  it  is  their  province  to  elaborate  and  discharge,  is  prepared  by  the  agency 
of  the  cells  which  are  successively  generated  in  their  interior. 

1  See  Dr.  Sprott  Boyd's  "Inaugural  Dissertation  on  the  Mucous  Membrane  of  the 
Stomach,"  in  the  "Edinb.  Med.  and  Surg.  Journ.,"  vol.  xlvi. ;  Dr.  Todd's  "Gulstonian  Lec- 
tures on  the  Physiology  of  the  Stomach,"  in  the  "Medical  Gazette,"  1839;  and  a  Memoir 
by  Dr.  Neill  on  the  "  Structure  of  the  Mucous  Membrane  of  the  Human  Stomach,"  in  the 
"  Amer.  Journ.  of  Med.  Sci.,"  Jan.  1851. — Dr.  Neill's  object  has  been  to  bring  prominently 
into  view  the  villous  structure  of  the  pyloric  portion  of  the  stomach,  and  the  arrangement 
of  the  capillaries  in  other  parts.  In  his  exclusive  attention  to  these,  however,  he  has 
under-estimated  the  import  of  the  orifices  of  the  gastric  follicles,  which  he  speaks  of  as 
"simply  the  subdivisions  of  the  cells  into  smaller  and  deeper  ones  by  the  arrangement  of 
the  bloodvessels."  There  cannot  be  the  slightest  doubt  that  this  arrangement  of  the 
bloodvessels  is  altogether  subordinate  to  the  existence  and  functional  activity  of  the  gastric 
follicles. 


GASTRIC   DIGESTION. 


417 


Fig.  125*. 


[The  function  of  these  tubular  glands,  according  to  Dr.  Kirkes,  appears  to  be 
the  production  of  cells  containing  the  digestive  or  gastric  fluid.  When  the 
stomach  is  empty,  the  glands  appear  to  be  at  rest ;  they  are  called  into  action 
by  the  introduction  of  food. — Their  walls  consist  essentially  of  tubular  inflec- 
tions of  the  basement  membrane  of  the  mucous  coat  of  the  stomach;  during 
active  digestion  they  are  filled  with  cells,  in  various  stages  of  development, 
engaged  in  the  elaboration  of  gastric  fluid. 

In  the  production  of  these  cells  minute  granules  appear  to  be  generated  at 
the  deeper  part  of  each  gland ;  two  or  more  of  these  granules,  grouping  together, 
form  nuclei,  and  are  developed  into  nucleated  cells.  In  those  parts  of  the  gland 
which  are  nearest  to  the  free  surface,  secondary  cells  are  developed  without  the 
primary  ones;  the  walls  of  the  latter  then  appear  to  coalesce  and  form  the  proper 
membrane  of  the  gland,  while  the  new  generation  of 
cells,  filled  with  gastric  fluid,  are  discharged  and  mixed 
with  the  food  in  the  stomach  (Fig.  125*). 

According  to  Bernard,  the  elaboration  of  the  gastric 
fluid  in  these  cells  seems  to  be  completed  only  when  they 
reach  the  surface,  for,  according  to  this  observer,  the 
mucous  membrane  is  not  acid  a  little  below  the  surface. 
It  has  been  suggested  by  Dr.  Brown-Sequard,  however, 
that  these  glands  may  be  concerned  in  the  elaboration 
of  some  other  constituent  of  the  gastric  juice — the  pep- 
sin, for  instance;  while  the  acid  constituents  are  de- 
veloped by  some  of  the  other  follicles  that  stud  the 
mucous  membrane  of  the  stomach. 

When  the  stomach  is  empty  and  inactive,  the  glands 
are  said  to  be  also  inactive  and  empty,  and  to  have  their 
walls  lined  with  cylindrical  epithelium  similar  to  that 
by  which  the  whole  surface  of  the  stomach  is  covered 
during  the  intervals  of  digestion. 

The  presence  of  this  epithelium  in  the  tubular  glands 
usually  closes  their  orifices,  so  that  during  fasting  they 
are  often  distinguishable  only  as  minute,  slightly  pro- 
minent papillae.  When  the  glands  again  commence 
secreting,  the  epithelium  separates  from  the  deeper 
part,  and  together  with  some  of  that  covering  the 
mucous  surface  of  the  stomach,  is  mixed  up  with 
the  newly-formed  cells  containing  the  gastric  fluid.1 — 
ED.] 

441.  The  nature  and  composition  of  the  Gastric  Juice  which  is  secreted  and 
poured  forth  by  this  follicular  apparatus,  have  been  the  subjects  of  much  dis- 
cussion among  Chemists;  and  though  certain  points  may  be  considered  as  satis- 
factorily determined,  there  are  others  which  still  remain  doubtful. — This  liquid, 
when  obtained  without  admixture  with  saliva,  is  clear,  transparent,  colorless  or 
slightly  yellow,  and  has  very  little  viscidity.  Its  specific  gravity  is  not  much 
above  that  of  water;  and  according  to  the  analysis  of  Frerichs,  it  does  not  con- 
tain above  1.72  per  cent,  of  solid  matter,  of  which  more  than  half  seems  to 
consist  of  the  peculiar  "ferment"  to  be  presently  described,  the  remainder 
being  composed  of  chlorides  and  phosphates  of  potass,  soda,  lime,  and  magnesia. 
Microscopic  examination  indicates  the  persistence  of  a  few  of  the  cells  exuviated 
from  the  interior  of  the  gastric  follicles ;  but  these  for  the  most  part  leave  no 
other  traces  than  their  nuclei  and  a  fine  molecular  matter  arising  from*  their 


One  of  the  tubular  follicles 
of  the  pig's  stomach,  after  Was- 
mann,  cut  obliquely  so  as  to 
display  the  upper  part  of  the 
cavity,  with  the  cylindrical  epi- 
thelium forming  its  walls.  At 
the  lower  part  of  the  follicle, 
the  external  nucleated  extremi- 
ties of  the  cylinders  of  epithe- 
lium are  seen. 


27 


"  Kirkes  and  Paget's  Manual  of  Physiology,"  p.  166,  Am.  Ed. 


418  OP   FOOD,    AND   THE   DIGESTIVE   PROCESS. 

disintegration.     The  most  characteristic  feature  of  the  gastric  fluid  is  its  decided 
acidity,  which  is  very  perceptible  to  the  taste.     With  regard  to  the  nature  of 

Fig.  126. 


Appearance  of  the  lining  membrane  of  the  Stomach,  in  an  injected  preparation:  A,  from  the  convex  surface 
of  the  rugse ;  B,  from  the  neighborhood  of  the  pylorus,  where  the  orifices  of  the  gastric  follicles  occupy  the 
interspaces  of  the  deepest  portions  of  the  vascular  network. 

the  acid,  however,  there  has  been  much  discrepancy  of  opinion  amongst  Chem- 
ists; for,  simple  as  the  problem  of  its  determination  might  seem,  yet  it  is  com- 
plicated by  the  very  peculiar  property  which  lactic  acid  possesses  of  decomposing 
the  alkaline  chlorides  at  a  certain  elevation  of  temperature,  the  degree  being  partly 
determined  by  the  strength  of  the  solution.  Hence,  supposing  lactic  acid  to  be 
present  in  the  stomach  with  chloride  of  sodium,  the  fluid  which  passes  over  by 
distillation  will  at  first  be  destitute  of  hydrochloric  acid;  but,  as  the  liquor 
becomes  more  concentrated,  and  the  temperature  rises,  hydrochloric  acid  will 
appear.  This,  it  has  been  alleged  by  Bernard,  R.  D.  Thomson,  Lehmann,  and 
other  Chemists,  is  the  true  source  of  the  hydrochloric  acid  which  may  be  always 
obtained  from  the  gastric  juice  by  this  process;  and  it  is  affirmed  by  them  that 
Lactic  acid  is  the  real  agent  in  the  solvent  process  to  which  that  fluid  is  sub- 
servient, the  presence  of  free  lactic  acid  in  the  stomach  having  been  determined 
by  other  means.  But,  however  true  this  conclusion  may  be  in  regard  to  dogs 
and  pigs,  which  are  the  animals  that  have  been  chiefly  experimented  on  for  this 
purpose,  there  appears  to  be  valid  evidence  that  it  is  not  applicable  to  Man.  In 
the  first  place,  the  great  readiness  with  which  hydrochloric  acid  was  obtained 
by  Prof.  Dunglison  from  the  pure  gastric  fluid  drawn  from  the  stomach  of 
Alexis  St.  Martin,  and  the  fact  that  the  smell  of  hydrochloric  acid  might  be 
distinctly  recognized  in  the  fresh  juice,1  are  strong  evidences  in  favor  of  the 
belief  that  (as  originally  maintained  by  Dr.  Prout)  free  hydrochloric  acid  is 
present  in  this  fluid,  and  that  it  is  the  principal  if  not  the  only  source  of  its 
acidity.  And  an  opportunity  having  been  recently  afforded  to  Dr.  Bence  Jones 
of  obtaining  pure  gastric  fluid,  and  this  having  been  placed  in  the  hands  of  Prof. 
Graham  for  examination,  this  distinguished  Chemist  has  succeeded  in  separating 
hydrochloric  acid  from  it  by  his  method  of  "  liquid  diffusion,"  which  is  not  open 
to  the  objection  that  applies  to  distillation;  and  although  he  has  found  free  lactic 
acid  to  be  also  present,  its  quantity  is  comparatively  small.8  The  truth  appears 
to  be,  that  both  the  hydrochloric  and  lactic  acids  may  give  to  the  gastric  fluid 
the  peculiar  solvent  power,  which  (as  will  be  presently  shown)  it  possesses  for 
albuminous  substances,  and  that  one  may  take  the  place  of  the  other;  so  that 

1  See  Prof.  Dunglison's  "Human  Physiology,"  7th  edit.,  vol.  i.  pp.  585-6. 

2  For  his  knowledge  of  this  fact,  the  Author  is  indebted  to  Prof.  Graham. — That  hydro- 
chloric acid  is  the  source  of  the  acidity  of  the  gastric  juice  has  also  been  maintained  by 
Enderlin("Canstatt's  Jahresbericht,"  1843,  p.  149),  and  recently  by  Hiibbenet  ("Disqui- 
sitiones  de  Succo  Gastrico,"  diss.  inaug.,  Dorpat,  1850. 


GASTRIC   DIGESTION.  419 

whilst  in  Man,  hydrochloric  acid  is  the  chief  source  of  the  acidity,  lactic  acid 
may  be  so  in  the  dog  and  pig.  Acetic,  butyric,  and  phosphoric  acids  have  also 
been  occasionally  met  with  in  the  gastric  fluid ;  but  they  can  scarcely  be  reckoned 
among  its  normal  constituents. 

442.  The  peculiar  organic  "ferment"  of  the  gastric  juice,  to  which  the  name 
of  Pepsin  has  been  given,  was  first  obtained  in  an  isolated  state  by  Wasmann; 
who  has  given  the  following  account  of  the  properties  and  reactions  of  that 
which  he  procured  from  the  mucous  membrane  of  the  stomach  of  the  Pig,  which 
greatly  resembles  that  of  Man.  When  this  membrane  is  digested  in  a  large 
quantity  of  water  at  from  85°  to  95°,  many  other  matters  are  removed  from  it 
besides  pepsin;  but  if  this  water  be  poured  off,  and  the  digestion  be  continued 
with  fresh  water  in  the  cold,  very  little  but  pepsin  is  then  taken  up.  Pepsin 
appears  to  be  but  sparingly  soluble  in  water;  when  its  solution  is  evaporated  to 
dryness,  there  remains  a  brown,  grayish,  viscid  mass,  with  the  odor  of  glue,  and 
having  the  appearance  of  an  extract.  The  solution  of  this  in  water  is  turbid, 
and  still  possesses  a  portion  of  the  characteristic  power  of  pepsin,  but  greatly 
reduced.  When  strong  alcohol  is  added  to  a  fresh  solution  of  pepsin,  the  latter 
is  precipitated  in  white  flocks,  which  may  be  collected  on  a  filter,  and  produce  a 
gray  compact  mass  when  dried.  Pepsin  enters  into  chemical  combination  with 
many  acids,  forming  compounds  which  still  redden  litmus  paper  ;  and  it  is  when 
thus  united  with  acetic  and  muriatic  acids,  that  its  solvent  powers  are  the  great- 
est.1— The  general  result  of  later  inquiries  has  been  to  confirm  the  views  laid 
down  in  the  following  statement  of  Wasmann' s  inquiries:  "In  regard  to  the 
solvent  power  of  pepsin  for  coagulated  albumen,  it  was  observed  by  M.  Wasmann 
that  a  liquid  which  contains  17-10,000ths  of  acetate  of  pepsin,  and  6  drops  of 
hydrochloric  acid  per  ounce,  possesses  a  very  sensible  solvent  power,  so  that  it 
will  dissolve  a  thin  slice  of  coagulated  albumen  in  the  course  of  six  or  eight  hours' 
digestion.  With  12  drops  of  hydrochloric  acid  per  ounce,  the  white  of  egg  is 
dissolved  in  two  hours.  A  liquid  which  contains  £  gr.  of  acetate  of  pepsin,  and 
to  which  hydrochloric  acid  and  white  of  egg  are  alternately  added,  so  long  as 
the  latter  dissolves,  is  capable  of  taking  up  210  grains  of  coagulated  white  of 
egg  at  a  temperature  between  95°  and  104°.  It  would  appear,  from  such  ex- 
periments, that  the  hydrochloric  acid  is  the  true  solvent,  and  that  the  action  of 
the  pepsin  is  limited  to  that  of  disposing  the  white  of  egg  to  dissolve  in  hydro- 
chloric acid.  The  acid  when  alone  dissolves  white  of  egg  by  ebullition,  just  as 
it  does  under  the  influence  of  pepsin ;  from  which  it  follows  that  pepsin  replaces 
the  effect  of  a  high  temperature,  which  is  not  possible  in  the  stomach.  The 
same  acid  with  pepsin  dissolved  blood,  fibrin,  meat  and  cheese ;  while  the  isolated 
acid  dissolved  only  an  insignificant  quantity  at  the  same  temperature;  but  when 
raised  to  the  boiling  point,  it  dissolved  nearly  as  much,  and  the  part  dissolved 
appeared  to  be  of  the  same  nature.  The  epidermis,  horn,  the  elastic  tissue 
(such  as  the  fibrous  membrane  of  arteries)  do  not  dissolve  in  a  dilute  acid  con- 
taining pepsin.  M.  Wasmann  has  remarked  that  the  pepsin  of  the  stomach  of 
the  pig  is  entirely  destitute  of  the  power  to  coagulate  milk,  although  the  pepsin 
of  the  stomach  of  the  calf  possesses  it  in  a  very  high  degree;  from  which  he  is 
led  to  suppose,  that  the  power  of  the  latter  depends  upon  a  particular  modifica- 

1  It  has  been  supposed  by  Prof.  Schmidt  (of  Dorpat),  that  the  union  of  pepsin  with  these 
and  other  acids  forms  a  "conjugated"  acid  (§  58,  note],  which  possesses  the  property  of 
forming  soluble  compounds  with  albuminous  and  other  azotized  substances ;  but  the  ex- 
istence of  such  an  acid  has  not  been  determined  by  the  analysis  of  any  combination  either 
with  a  mineral  base  or  with  an  albuminous  substance  ;  and  the  numerous  experiments 
which  have  been  made  by  Prof.  Lehmann  regarding  the  digestive  agents  and  substances 
to  be  digested,  indicate  no  such  definite  proportion  between  them,  as  this  view  of  the  con- 
stitution of  the  former  would  require. 


420  OF   FOOD,    AND   THE  DIGESTIVE   PROCESS. 

tion  of  pepsin,  or  perhaps  upon  another  substance  accompanying  it,  which  ceases 
to  be  formed  when  the  young  animal  is  no  longer  nourished  by  the  milk  of  its 
mother."1 

443.  It  is  only  when  either  alimentary  or  some  other  substances  capable  of 
exciting  irritation  are  present  in  the  Stomach,  that  this  acid  secretion  is  poured 
forth.  So  long  as  it  is  empty,  the  secretion  which  moistens  its  walls  is  neutral 
or  even  alkaline;  but,  as  soon  as  food  is  taken,  acid  is  poured  forth,  and  this  in 
increasing  quantities,  until  a  certain  time  after  the  commencement  of  the  digest- 
ive process,  when  the  acidity  of  the  stomach  is  at  its  maximum.  In  proportion 
as  the  alimentary  matter  is  dissolved,  however,  and  is  either  at  once  absorbed, 
or  escapes  through  the  pyloric  orifice,  the  acidity  of  the  stomach  diminishes ;  and 
as  soon  as  its  cavity  is  emptied,  the  secretion  of  its  walls  is  neutral  again.2 — 
A  very  important  series  of  observations  on  the  conditions  under  which  the 
Gastric  juice  is  secreted,  was  made  some  years  since  by  Dr.  Beaumont,  in  the 
remarkable  case  of  Alexis  St.  Martin,  already  several  times  referred  to.3  "The 
inner  coat  of  the  stomach  (as  seen  through  the  fistulous  orifice)  in  its  natural 
and  healthy  state,  is  of  a  light  or  pale  pink  color,  varying  in  its  hues,  according 
to  its  full  or  empty  state.  It  is  of  a  soft  or  velvet-like  appearance,  and  is  con- 
stantly covered  with  a  very  thin,  transparent,  viscid  mucus,  lining  the  whole 
interior  of  the  organ.  By  applying  aliment  or  other  irritations,  to  the  internal 
coat  of  the  stomach,  and  observing  the  effect  through  a  magnifying  glass,  in- 
numerable lucid  points,  and  very  fine  [nervous  or  vascular]  papillae  can  be  seen 
arising  from  the  villous  membrane,  and  protruding  through  the  mucous  coat, 
from  which  distils  a  pure,  limpid,  colorless,  slightly  viscid  fluid."  (The  papillae 
here  described  appear  to  be  the  orifices  of  the  gastric  follicles,  which  are  usually 
closed  by  their  epithelial  cells  during  fasting,  and  which  would  seem  to  become 
prominent  when  the  vis  d  tergo  of  the  secreted  fluid  first  causes  this  plug  of  cells 
to  be  cast  forth.)  "The  fluid  thus  excited  is  invariably  distinctly  acid.  The 
mucus  of  the  stomach  is  less  fluid,  more  viscid  or  albuminous,  semi-opaque, 
sometimes  a  little  saltish,  and  does  not  possess  the  slightest  character  of  acidity. 
The  gastric  fluid  never  appears  to  be  accumulated  in  the  cavity  of  the  stomach 
while  fasting ;  and  is  seldom,  if  ever,  discharged  from  its  proper  secerning 
vessels,  except  when  excited  by  the  natural  stimulus  of  aliment,  mechanical 
irritation  of  tubes,  or  other  excitants.  When  aliment  is  received,  the  juice  is 

fiven  out  in  exact  proportion  to  its  requirements  for  solution,  except  when  more 
>od  has  been  taken  than  is  necessary  for  the  wants  of  the  system. "-^-The  ob- 
servations of  Dr.  Beaumont  have  been  confirmed  by  those  of  M.  Blondlot4  and 
of  M.  Cl.  Bernard,5  which  were  made  upon  Dogs,  in  whose  stomachs  fistulous 
openings  were  maintained  for  a  length  of  time.  They  found  that  the  flow  of 
gastric  fluid  is  more  excited  by  pepper,  salt,  and  soluble  stimulants,  than  it  is 
by  mechanical  irritation ;  and  that  if  mechanical  irritation  be  carried  beyond 
certain  limits,  so  as  to  produce  pain,  the  secretion,  instead  of  being  more  abund- 
ant, diminishes  or  ceases  entirely;  whilst  a  ropy  mucus  is  poured  out  instead, 
and  the  movements  of  the  stomach  are  considerably  increased.  The  animal  at 
the  same  time  appears  ill  at  ease,  is  agitated,  has  nausea,  and,  if  the  irritation 
be  continued,  actual  vomiting;  and  bile  has  been  observed  to  flow  into  the 
stomach,  and  escape  by  the  fistulous  opening.  Similar  disorders  of  the  func- 
tions of  the  stomach  result  from  violent  pain  in  other  parts  of  the  body;  the 

1  Prof.  Graham's  "Elements  of  Chemistry,"  p.  697,  Am.  Ed. 
a  See  Dr.  Bence  Jones,  in  "  Medical  Times,"  June  14,  1852. 

3  See  Dr.  Beaumont's  "Experiments  and  Observations  on  the  Gastric  Juice  and  the 
Physiology  of  Digestion,"  reprinted  with  notes  by  Dr.  Andrew  Combe,  Edinb.,  1838. 
*  "Traite  Analytique  de  la  Digestion." 
6  "Archiv.  d'Anat.  G£n.  et  de  Physiol.,"  Jan.  1846. 


GASTRIC   DIGESTION.  ,        421 

process  of  digestion  in  such  cases  being  suspended,  and  sometimes  vomiting  ex- 
cited. When  acidulated  substances,  as  food  rendered  acid  by  the  addition  of  a 
little  vinegar,  were  introduced  into  the  stomach,  the  quantity  of  gastric  fluid 
poured  out  was  much  smaller,  and  the  digestive  process  consequently  slower, 
than  when  similar  food,  rendered  alkaline  by  a  weak  solution  of  carbonate  of 
soda,  was  introduced.  If,  however,  instead  of  a  weak  solution,  carbonate  of 
soda  in  crystal  or  in  powder  was  introduced  into  the  stomach,  a  large  quantity 
of  mucus  and  bile,  instead  of  gastric  fluid,  flowed  into  the  stomach ;  and  vomit- 
ing and  purging  very  often  followed.  When  very  cold  water,  or  small  pieces  of 
ice,  were  introduced  into  the  stomach,  the  mucous  membrane  was  at  first  rendered 
very  pallid;  but  soon  a  kind  of  reaction  followed,  the  membrane  became  turgid 
with  blood,  and  a  large  quantity  of  gastric  fluid  was  secreted.  If,  however,  too 
much  ice  was  employed,  the  animal  appeared  ill,  and  shivered ;  and  digestion, 
instead  of  being  rendered  more  active,  was  retarded.  Moderate  heat,  applied 
to  the  mucous  surface  of  the  stomach,  appeared  to  have  no  particular  action  on 
digestion ;  but  a  high  degree  of  heat  produced  most  serious  consequences.  Thus, 
the  introduction  of  a  little  boiling  water  threw  the  animal  at  once  into  a  kind 
of  adynamic  state,  which  was  followed  by  death  in  three  or  four  hours ;  the 
mucous  membrane  of  the  stomach  was  found  red  and  swollen,  whilst  an  abund- 
ant exudation  of  blackish  blood  had  taken  place  into  the  cavity  of  the  organ. 
Similar  injurious  effects  resulted  in  a  greater  or  less  degree,  from  the  introduc- 
tion of  other  irritants,  such  as  nitrate  of  silver  or  ammonia ;  the  digestive  func- 
tions being  at  once  abolished,  and  the  mucous  surface  of  the  organ  rendered 
highly  sensitive. 

444.  That  the  quantity  of  the  Gastric  Juice  secreted  from  the  walls  of  the 
stomach  depends  rather  upon  the  general  requirements  of  the  system,  than  upon 
the  quantity  of  food  introduced  into  the  digestive  cavity,  is  a  principle  of  the 
highest  practical  importance,  and  cannot  be  too  steadily  kept  in  view  in  Dietetics. 
A  definite  proportion  only  of  aliment  can  be  perfectly  digested  in  a  given  quan- 
tity of  the  fluid ;  the  action  of  which,  like  that  of  other  chemical  operations, 
ceases  after  having  been  exercised  on  a  fixed  and  definite  amount  of  matter. 
"  When  the  juice  has  become  saturated,  it  refuses  to  dissolve  more;  and,  if  an 
excess  of  food  has  been  taken,  the  residue  remains  in  the  stomach,  or  passes 
into  the  bowels  in  a  crude  state,  and  becomes  a  source  of  nervous  irritation,  pain, 
and  disease,  for  a  long  time/'  The  unfavorable  effect  of  an  undue  burthen  of 
food  upon  the  Stomach  itself,  interferes  with  its  healthy  action;  and  thus  the 
quantity  really  appropriate  is  not  dissolved.  The  febrile  disturbance  is  thus 
increased;  and  the  mucous  membrane  of  the  stomach  exhibits  evident  indica- 
tions of  its  morbid  condition.  The  description  of  these  indications  given  by 
Dr.  Beaumont,  is  peculiarly  graphic,  as  well  as  Hygienically  important.  u  In 
disease,  or  partial  derangement  of  the  healthy  function,  the  mucous  membrane 
presents  various  and  essentially  different  appearances.  In  febrile  conditions  of 
the  system,  occasioned  by  whatever  cause — obstructed  perspiration,  undue  ex- 
citement by  stimulating  liquors,  overloading  the  stomach  with  food,  fear,  anger, 
or  whatever  depresses  or  disturbs  the  nervous  system — the  villous  coat  becomes 
sometimes  red  and  dry,  at  other  times  pale  and  moist,  and  loses  its  smooth  and 
healthy  appearance ;  the  secretions  become  vitiated,  greatly  diminished,  or  even 
suppressed;  the  coat  of  mucus  scarcely  perceptible,  the  follicles  flat  and  flaccid, 
with  secretions  insufficient  to  prevent  the  papillae  from  irritation.  There  are 
sometimes  found,  on  the  internal  coat  of  the  stomach,  eruptions  of  deep  red 
pimples,  not  numerous,  but  distributed  here  and  there  upon  the  villous  mem- 
brane, rising  above  the  surface  of  the  mucous  coat.  These  are  at  first  sharp- 
pointed,  and  red,  but  frequently  become  filled  with  white  purulent  matter.  At 
other  times,  irregular,  circumscribed  red  patches,  varying  in  size  and  extent 
from  half  an  inch  to  an  inch  and  a  half  in  circumference,  are'  fimnd  on  the 


422  OF   FOOD,    AND   THE   DIGESTIVE  PROCESS. 

internal  coat.  These  appear  to  be  the  effects  of  congestion  in  the  minute  blood- 
vessels of  the  stomach.  There  are  also  seen  at  times  small  aphthous  crusts,  in 
connection  with  these  red  patches.  Abrasion  of  the  lining  membrane,  like  the 
rolling-up  of  the  mucous  coat  into  small  shreds  or  strings,  leaving  the  papillae 
bare  for  an  indefinite  space,  is  not  an  uncommon  appearance.  These  diseased 
appearances,  when  very  slight,  do  not  always  affect  essentially  the  gastric  appa- 
ratus. When  considerable,  and  particularly  when  there  are  corresponding 
symptoms  of  disease — as  dryness  of  the  mouth,  thirst,  accelerated  pulse,  &c. — 
no  gastric  juice  can  be  extracted  by  the  alimentary  stimulus.  Drinks  are  imme- 
diately absorbed  or  otherwise  disposed  of;  but  food  taken  in  this  condition  of 
the  stomach  remains  undigested  for  twenty-four  or  forty-eight  hours,  or  more, 
increasing  the  derangement  of  the  alimentary  canal,  and  aggravating  the  general 
symptoms  of  disease.  After  excessive  eating  or  drinking,  chymification  is  re- 
tarded ;  and,  though  the  appetite  be  not  always  impaired  at  first,  the  fluids 
become  acrid  and  sharp,  excoriating  the  edges  of  the  aperture,  and  almost  in- 
variably producing  aphthous  patches  and  the  other  indications  of  a  diseased  state 
of  the  internal  membrane.  Vitiated  bile  is  also  found  in  the  stomach  under 
these  circumstances,  and  flocculi  of  mucus  are  more  abundant  than  in  health. 
Whenever  this  morbid  condition  of  the  stomach  occurs,  with  the  usual  accom- 
panying symptoms  of  disease,  there  is  generally  a  corresponding  appearance  of 
the  tongue.  When  a  healthy  state  of  the  stomach  is  restored,  the  tongue  inva- 
riably becomes  clean."1 

445.  That  the  secretion  of  Gastric  Juice  is  affected  in  a  very  marked  manner 
by  conditions  of  the  Nervous  system,  is  indicated  by  the  effect  of  mental  emotions 
in  putting  an  immediate  stop  to  the  digestive  process,  when  it  is  going  on  with 
full  vigor.  But  it  is  still  more  conclusively  proved  by  the  effect  of  division  of 
the  Pneumogastric  nerve ;  which  almost  instantaneously  checks  the  elaboration 
of  the  fluid.  The  most  satisfactory  evidence  of  the  influence  of  this  operation 
is  afforded  by  the  experiments  of  M.  Bernard  upon  dogs  in  whose  stomachs 
fistulous  orifices  had  been  established.  For  when  the  section  was  made  during 
the  free  flow  of  gastric  juice  (through  a  canula  previously  introduced  into  the 
stomach),  excited  by  the  presence  of  an  alimentary  bolus,  the  flow  immediately 
ceased,  and  the  mucous  membrane,  which  had  been  tense  and  turgid  the  moment 
before,  became  withered  and  pale.  On  introducing  the  finger  into  the  stomach 
itself,  the  walls  were  perceived  to  be  perfectly  flaccid,  and  there  was  no  longer 
the  gentle  pressure  which  had  been  previously  felt.  The  rapidity  and  complete- 
ness of  this  influence  are  further  demonstrated  by  the  following  ingenious  ex- 
periment, devised  by  M.  Bernard.  The  two  substances  emulsin  (the  albuminous 
matter  found  in  almonds)  and  amyydalin  (the  active  principle  of  bitter  almonds) 

*  Dr.  A.  Combe's  commentary  on  the  above  passage  is  too  apposite  to  be  omitted.  "  Many 
persons  who  obviously  live  too  freely,  protest  against  the  fact,  because  they  feel  no  imme- 
diate inconvenience,  either  from  the  quantity  of  food,  or  the  stimulants  in  which  they 
habitually  indulge ;  or,  in  other  words,  because  they  experience  no  pain,  sickness,  or 
headache — nothing,  perhaps,  except  slight  fulness  and  oppression,  which  soon  go  off. 
Observation  extended  over  a  sufficient  length  of  time,  however,  shows  that  the  conclusion 
drawn  is  entirely  fallacious,  and  that  the  real  amount  of  injury  is  not  felt  at  the  moment, 
merely  because,  for  a  wise  purpose,  nature  has  deprived  us  of  any  consciousness  of  either 
the  existence  or  the  state  of  the  stomach  during  health.  In  accordance  with  this,  Dr. 
Beaumont's  experiments  prove,  that  extensive  ery thematic  inflammation  of  the  mucous  coat 
of  the  stomach  was  of  frequent  occurrence  in  St.  Martin  after  excesses  in  eating,  and 
especially  in  drinking,  even  when  no  marked  general  symptom  was  pi-esent  to  indicate  its 
existence.  Occasionally,  febrile  heat,  nausea,  headache,  and  thirst  were  complained  of., 
but  not  always.  Had  St.  Martin's  stomach,  and  its  inflamed  patches,  not  been  visible  to 
the  eye,  he  too  might  have  pleaded  that  his  temporary  excesses  did  him  no  harm ;  but, 
when  they  presented  themselves  in  such  legible  characters  that  Dr.  Beaumont  could  not 
miss  seeing  them,  argument  and  supposition  were  at  an  end,  and  the  broad  fact  could  not 
be  denied."  ' 


GASTRIC   DIGESTION.  423 

are  quite  innocuous  when  administered  separately ;  but  when  they  are  united,  a 
production  of  hydrocyanic  acid  takes  place ;  so  th  t,  if  this  should  occur  in  the 
stomach  of  an  animal,  the  poison  proves  fatal,  provided  that  it  be  generated  in 
sufficient  quantity.  If,  however,  the  emulsin  be  given  first,  and  the  amygdalin 
half  an  hour  afterwards,  no  such  result  occurs ;  because  the  properties  of  the 
emulsin  are  so  changed  by  the  gastric  fluid  secreted  during  the  interval,  that  it 
no  longer  generates  hydrocyanic  acid  with  amygdalin.  But  if  the  emulsin  be 
given  to  an  animal  whose  pneumogastric  nerves  have  been  just  divided,  and  the 
amygdalin  be  administered  half  an  hour  subsequently,  the  effect  is  the  same  as 
if  the  two  substances  had  been  given  at  one  time  ;  showing  that  no  secretion  of 
gastric  fluid  could  have  taken  place. — The  first  obvious  effects  of  this  operation 
are  vomiting  (in  animals  that  are  capable  of  it)  and  loathing  of  food ;  and  the 
arrestment  of  the  digestive  process  is  indicated,  on  post-mortem  examination 
some  hours  afterwards,  by  the  absence  of  any  digestive  change  in  food  that  may 
have  been  taken  just  previously  to  the  operation,  and  that  has  not  been  ejected 
from  the  stomach. 

446.  But,  as  was  first  proved  by  Dr.  John  Reid,1  a  re-establishment  of  the  diges- 
tive power  manifests  itself  after  an  interval  of  some  days,  if  the  animals  should 
survive  so  long.  In  the  animals  which  died  within  the  first  four  or  five  days, 
no  indication  of  this  restoration  could  be  discovered  by  Dr.  R. ;  in  those  which 
survived  longer,  great  emaciation  took  place  ;  but  when  life  was  sufficiently  pro- 
longed, the  power  of  assimilation  seemed  almost  completely  restored.  This  was 
the  casein  four  out  of  the  seventeen  dogs  experimented  on;  and  the  evidence 
of  this  restoration  consisted  in  the  recovery  of  flesh  and  blood  by  the  animals, 
the  vomiting  of  half  digested  food  permanently  reddening  litmus  paper,  the 
disappearance  of  a  considerable  quantity  of  alimentary  matter  from  the  intestinal 
canal,  and  the  existence  of  chyle  in  the  lacteals.  It  may  serve  to  account  in 
some  degree  for  the  contrary  results  obtained  by  other  experimenters,  to  state 
that  seven  out  of  Dr.  R/s  seventeen  experiments  were  performed  before  he  ob- 
tained any  evidence  of  digestion  after  the  operation,  and  that  the  four  which 
furnished  this  followed  one  another  almost  in  succession  ;  so  that  it  is  easy  to 
understand  why  those,  who  were  satisfied  with  a  small  number  of  experiments, 
should  have  been  led  to  deny  it  altogether. — Another  series  of  experiments  was 
performed  by  Dr.  Reid,  for  the  purpose  of  testing  the  validity  of  the  results 
obtained  by  Sir  B.  Brodie,  relative  to  the  effects  of  section  of  the  Par  Vagum 
upon  the  secretions  of  the  stomach,  after  the  introduction  of  arsenious  acid  into 
the  system.  According  to  that  eminent  Surgeon  and  Physiologist,2  when  the 
poison  was  introduced  after  the  Pneumogastric  had  been  divided  on  each  side, 
the  quantity  of  the  protective  mucous  and  watery  secretions  was  much  less  than 
usual,  although  obvious  marks  of  inflammation  were  present.  In  order  to  avoid 
error  as  much  as  possible,  Dr.  Reid  made  five  sets  of  experiments,  employing 
two  dogs  in  each,  as  nearly  as  possible  of  equal  size  and  strength,  introducing 
the  same  quantity  of  the  poison  into  the  system  of  each  in  the  same  manner,  but 
cutting  the  Vagi  in  one,  and  leaving  them  entire  in  the  other.  This  comparative 
mode  of  experimenting  is  obviously  the  only  one  admissible  in  such  an  investiga- 
tion. Its  result  was  in  every  instance  opposed  to  the  statements  of  Sir  B.  Brodie ; 
the  quantity  of  the  mucous  and  watery  secretions  of  the  stomach  being  nearly 
the  same  in  each  individual  of  the  respective  pairs  subjected  to  experiment;  so 
that  their  production  can  no  longer  be  referred  to  the  influence  of  the  Pneumo- 
gastric nerves.  Moreover,  the  appearances  of  inflammation  were,  in  four  out 
of  the  five  cases,  greatest  in  the  animals  whose  Yagi  were  left  entire ;  and  this 

1  "Edinb.  Med.  and  Surg.  Journ.,"  April,  1839.;  and  "Physiological,  Anatomical,  and 
Pathological  Researches,"  CHAP.  v. — Dr.  Reid's  results  have  been  confirmed  as  to  this  im- 
portant particular  by  Hiibbenet  (Op.  cit.). 

2  "  Philosophical  Transactions,"  1814,  p.  102. 


424  OF   FOOD,    AND   THE   DIGESTIVE   PROCESS. 

seemed  to  be  referable  to  the  longer  duration  of  their  lives  after  the  arsenic  had 
been  introduced.  The  results  of  Sir  B.  Brodie's  experiments  may  perhaps  be 
explained,  by  the  speedy  occurrence  of  death  in  the  subjects  of  them,  consequent 
(it  may  be)  upon  the  want  of  sufficiently  free  respiration,  which  was  carefully 
guarded  against  by  Dr.  Reid. 

447.  It  must  be  held  as  demonstrated  by  these  experiments,  then,  that  all 
the  arguments  which  have  been  drawn  from  the  effects  of  lesion  of  the  Pneumo- 
gastrics  upon  the  functions  of  the  Stomach,  in  favor  of  the  doctrine  that  Secre- 
tion depends  upon  Nervous  agency,  must  be  set  aside.  That  these  nerves  have 
an  important  influence  on  the  gastric  secretion,  is  evident  from  the  deficiency 
in  its  amount  soon  after  their  section,  as  well  as  from  other  facts.  But  this  is 
a  very  different  proposition  from  that  just  alluded  to;  and  the  difference  has 
been  very  happily  illustrated  by  Dr.  Reid.  "  The  movements  of  a  horse,"  he 
observes,  "  are  independent  of  the  rider  on  his  back — in  other  words,  the  rider 
does  not  furnish  the  conditions  necessary  for  the  movements  of  the  horse; — but 
every  one  knows  how  .much  these  movements  may  be  influenced  by  the  hand  and 
heel  of  the  rider."  It  may  be  hoped,  then,  that  physiologists  will  cease  to 
adduce  the  oft-cited  experiments  of  Dr.  Wilson  Philip,  in  favor  of  the  hypothesis 
(for  such  it  must  be  termed)  that  secretion  is  dependent  upon  nervous  influence, 
and  that  this  is  identical  with  galvanism.  Additional  evidence  of  their  fallacy 
is  derived  from  the  fact  mentioned  by  Dr.  Reid,  that  the  usual  mucous  secre- 
tions of  the  stomach  were  always  found;  and  they  are  further  invalidated  by 
the  testimony  of  Miiller,  who  denies  that  galvanism  has  any  peculiar  influence 
in  re-establishing  the  gastric  secretion,  when  it  has  been  checked  by  section  of 
the  nerves. 

,  448.  Our  knowledge  of  the  nature  of  the  process  of  Gastric  Digestion  has 
been  greatly  advanced  by  recent  inquiries;  and  we  are  now  in  a  condition  to 
state  with  considerable  precision  what  it  is,  and  what  it  is  not,  the  province  of 
the  gastric  juice  to  effect. — There  can  no  longer  be  any  doubt  that  the  opera- 
tion is  one  essentially  of  chemical  solution;  and  that  the  vital  attributes  of  the 
Stomach  are  only  exercised  in  the  preparation  of  the  solvent,  and  in  the  per- 
formance of  those  movements  which  promote  its  action  on  the  alimentary  mat- 
ters submitted  to  it.  The  first  series  of  facts  which  clearly  demonstrated  this 
position,  were  those  that  resulted  from  the  very  pains-taking  observations  made 
by  Dr.  Beaumont,  in  the  case  of  St.  Martin  already  referred  to.  By  introducing 
a  tube  of  India-rubber  into  the  empty  stomach,  Dr.  B.  was  able  to  obtain  a 
supply  of  gastric  juice  whenever  he  desired  it,  the  tube  serving  the  purpose  of 
stimulating  the  follicles  to  pour  forth  their  secretion,  and  at  the  same  time  con- 
veying it  away;  and  with  the  fluid  thus  obtained,  he  was  able  to  make  various 
experiments,  which  showed  that  the  change  which  it  effects  upon  alimentary 
matter,  when  it  is  kept  at  a  temperature  of  98°  or  100°,  and  frequently  agitated, 
is  not  less  complete  than  that  which  takes  place  when  the  same  matter  is  sub- 
mitted to  its  operation  within  the  stomach,  but  requires  a  longer  time.  This 
is  readily  accounted  for  when  we  remember,  that  no  ordinary  agitation  can  pro- 
duce the  same  effect  with  the  curious  movements  of  the  stomach ;  and  that  the 
continual  removal,  from  its  cavity,  of  the  matter  which  has  been  already  dis- 
solved, must  aid  the  operation  of  the  solvent  on  the  remainder.  The  following 
is  one  out  of  many  experiments  detailed  by  Dr.  Beaumont,  "  At  11£  o'clock, 
A.  M.,  after  having  kept  the  lad  fasting  for  17  hours,  I  introduced  a  gum-elastic 
tube,  and  drew  off  one  ounce  of  pure  gastric  liquor,  unmixed  with  any  other 
matter,  except  a  small  proportion  of  mucus,  into  a  three-ounce  vial.  I  then 
took  a  solid  piece  of  boiled  recently-salted  beef,  weighing  three  drachms,  and 
put  it  into  the  liquor  in  the  vial ;  corked  the  vial  tight,  and  placed  it  in  a  sauce- 
pan filled  with  water,  raised  to  the  temperature  of  100°,  and  kept  at  that  point 
on  a  nicely-regulated  sand-bath.  In  forty  minutes,  digestion  had  distinctly 


GASTRIC   DIGESTION.  425 

commenced  over  the  surface  of  the  meat.  In  fifty  minutes,  the  fluid  had  be- 
come quite  opaque  and  cloudy;  the  external  texture  began  to  separate  and 
become  loose.  In  sixty  minutes,  chyme  began  to  form.  At  1  o'clock  P.  M. 
(digestion  having  progressed  with  the  same  regularity  as  in  the  last  half  hour), 
the  cellular  texture  seemed  to  be  entirely  destroyed,  leaving  the  muscular  fibres 
loose  and  unconnected,  floating  about  in  fine  small  shreds,  very  tender  and  soft. 
At  3  o'clock,  the  muscular  fibres  had  diminished  one-half,  since  the  last  exami- 
nation. At  5  o'clock,  they  were  nearly  all  digested;  a  few  fibres  only  remain- 
ing. At  7  o'clock,  the  muscular  texture  was  completely  broken  down,  and 
only  a  few  of  the  small  fibres  could  be  seen  floating  in  the  fluid.  At  9  o'clock, 
every  part  of  the  meat  was  completely  digested.  The  gastric  juice,  when  taken 
from  the  stomach,  was  as  clear  and  transparent  as  water.  The  mixture  in  the 
vial  was  now  about  the  color  of  whey.  After  standing  at  rest  a  few  n^nutes,  a 
fine  sediment  of  the  color  of  the  meat  subsided  to  the  bottom  of  the  vial. — A 
piece  of  beef,  exactly  similar  to  that  placed  in  the  vial,  was  introduced  into  the 
stomach,  through  the  aperture,  at  the  same  time.  At  1*2  o'clock  it  was  with- 
drawn, and  found  to  be  as  little  affected  by  digestion  as  that  in  the  vial ;  there 
was  little  or  no  difference  in  their  appearance.  It  was  returned  to  the  stomach; 
and,  on  the  string  being  drawn  out  at  1  o'clock  P.  M.,  the  meat  was  found  to 
be  all  completely  digested  and  gone.  The  effect  of  the  gastric  juice  on  the 
piece  of  meat  suspended  in  the  stomach,  was  exactly  similar  to  that  in  the  vial, 
only  more  rapid  after  the  first  half  hour,  and  sooner  completed.  Digestion 
commenced  on,  and  was  confined  to,  the  surface  entirely  in  both  situations. 
Agitation  accelerated  the  solution  in  the  vial,  by  removing  the  coat  that  was 
digested  on  the  surface,  enveloping  the  remainder  of  the  meat  in  the  gastric 
fluid,  and  giving  this  fluid  access  to  the  undigested  portions."1  Many  variations 
were  made  in  other  experiments ;  some  of  which  strikingly  displayed  the  effects 
of  thorough  mastication,  in  aiding  both  natural  and  artificial  digestion. 

449.  The  attempt  was  made  by  Dr.  Beaumont  to  determine  the  relative 
digestibility  of  different  articles  of  diet,  by  observing  the  length  of  time  requisite 
for  their  solution.3  But,  as  he  himself  points  out,  the  rapidity  of  digestion 
varies  so  greatly,  according  to  the  quantity  eaten,  the  nature  and  amount  of  the 
previous  exercise,  the  interval  since  the  preceding  meal,  the  state  of  health,  the 
condition  of  the  mind,  and  the  nature  of  the  weather,  that  a  much  more  ex- 
tended inquiry  would  be  necessary  to  arrive  at  results  to  be  depended  on.  Some 
important  inferences  of  a  general  character,  however,  may  be  drawn  from  his 
inquiries. — It  seems  to  be  a  general  rule,  that  the  flesh  of  wild  animals  is  more 
easy  of  digestion,  than  that  of  the  domesticated  races  wWch  approach  them  most 
nearly.  This  may,  perhaps,  be  partly  attributed  to  the  small  quantity  of  fatty 
matter  that  is  mixed  up  with  the  flesh  of  the  former,  whilst  that  of  the  latter  is 
largely  pervaded  by  it.  For  it  appears  from  Dr.  B/s  experiments,  that  the 
presence  in  the  stomach  of  any  substance  which  is  difficult  of  digestion,  inter- 
feres with  the  solution  of  food  that  would  otherwise  be  soon  reduced.  It  seems 
that,  on  the  whole,  Beef  is  more  speedily  reduced  than  Mutton,  and  Mutton 
sooner  than  either  Veal  or  Pork.  Fowls  are  far  from  possessing  the  digestibility 
that  is  ordinarily  imputed  to  them;  but  Turkey  is,  of  all  kinds  of  flesh  except 
Venison,  the  most  soluble. — Dr.  Beaumont's  experiments  further  show,  that 
bulk  is  as  necessary  for  healthy  digestion,  as  the  presence  of  the  nutrient  prin- 

1  Experiments  2  and  3  of  First  Series. 

2  It  is  important  to  bear  in  mind  that  the  digestibility  of  different  substances  bears  no 
relation  to  their  nutrient  value,  which  is  entirely  dependent  on  their  chemical  composition. 
Of  course,  however  nutritious  a  substance  may  be,  it  is  valueless  as  an  article  of  diet  if  it 
cannot  be  dissolved ;  but,  on  the  other  hand,  substances  which  are  very  easily  digested 
(such  as  farinaceous  matters)  may  have  a  low  nutritive  value,  though  containing  but  a 
very  small  proportion  of  azotized  constituents. 


426  OP   FOOD,    AND   THE   DIGESTIVE   PROCESS. 

ciple  itself.  This  fact  has  been  long  known  by  experience  to  uncivilized  nations. 
The  Kamschatdales,  for  example,  are  in  the  habit  of  mixing  earth  or  saw-dust 
with  the  train-oil,  on  which  alone  they  are  frequently  reduced  to  live.  The 
Veddahs,  or  wild  hunters  of  Ceylon,  on  the  same  principle,  mingle  the  pounded 
fibres  of  soft  and  decayed  wood  with  the  honey,  on  which  they  feed  when  meat 
is  not  to  be  had  ;  and  on  one  of  them  being  asked  the  reason  of  the  practice,  he 
replied,  "I  cannot  tell  you,  but  I  know  that  the  belly  must  be  filled."  It  is 
further  shown  by  Dr.  B.,  that  soups  and  fluid  diet  are  not  more  readily  chymified 
than  solid  aliment,  and  are  not  alone  fit  for  the  support  of  the  system ;  and  this, 
also,  is  conformable  to  the  well-known  results  of  experience ;  for  a  dyspeptic 
patient  will  frequently  reject  chicken-broth,  when  he  can  retain  solid  food  or  a 
richer  soup.  Perhaps,  as  Dr.  A.  Combe  remarks,  the  little  support  gained  from 
fluid  diet,  is  due  to  the  rapid  absorption  of  the  watery  part  of  it;  so  that  the 
really  nutritious  portion  is  left  in  too  soft  and  concentrated  a  state,  to  excite  the 
healthy  action  of  the  stomach. — Dr.  Beaumont  also  ascertained,  that  moderate 
exercise  facilitates  digestion,  though  severe  and  fatiguing  exercise  retards  it. 
If  even  moderate  exercise  be  taken  immediately  after  a  full  meal,  however,  it  is 
probably  rather  injurious  than  beneficial ;  but  if  an  hour  be  permitted  to  elapse, 
or  if  the  quantity  of  food  taken  has  been  small,  it  is  of  decided  benefit.  The 
influence  of  temperature  on  the  process  of  solution  is  remarkably  shown  in  some 
of  Dr.  B.'s  experiments.  He  found  that  the  gastric  juice  had  scarcely  any 
influence  on  the  food  submitted  to  it,  when  the  bottle  was  exposed  to  the  cold 
air,  instead  of  being  kept  at  a  temperature  of  100°.  He  observed  on  one  occa- 
sion, that  the  injection  of  a  single  gill  of  water  at  50°  into  the  stomach,  sufficed 
to  lower  its  temperature  upwards  of  30°;  and  that  its  natural  heat  was  not  re- 
stored for  more  than  half  an  hour.  Hence  the  practice  of  eating  ice  after  din- 
ner, or  even  of  drinking  largely  of  cold  fluids,  is  very  prejudicial  to  digestion. 

450.  It  is  far  from  being  true,  however,  that  according  to  the  older  views  of 
the  power  of  the  Gastric  juice,  it  is  capable  of  acting  upon  all  the  nutritive 
components  of  the  food.  The  mistake  probably  arose  from  the  reduction  to 
which  these  matters  are  subjected  in  digestion,  the  alimentary  bolus  being 
completely  disintegrated,  and  its  particles  saturated  with  the  fluids  of  the 
stomach,  so  that  the  whole  forms  a  homogeneous  liquid  of  pultaceous  consist- 
ence, to  which  the  name  of  chyme  is  given.  This  chyme  will  of  course  vary 
greatly  in  its  composition,  according  to  the  proportion  of  the  different  aliment- 
ary substances  that  have  entered  into  the  composition  of  the  food;  and  its 
appearance,  also,  is  far  from  uniform,  being  sometimes  like  gruel,  but  sometimes 
more  creamy,  always,  towever,  having  a  strong  acid  reaction. — All  the  more 
recent  and  accurate  experiments  of  those  who  have  studied  the  chemistry  of 
digestion,  lead  to  the  conclusion  that  the  solvent  powers  of  the  Gastric  Juice 
are  entirely  limited  to  azotized  substances;  and  that  it  exerts  no  action  whatever 
either  upon  starchy,  saccharine,  or  oleaginous  matters.  Although  the  change 
in  the  starchy  particles,  which  commenced  in  the  mouth,  is  usually  continued 
in  the  stomach,  yet  its  continuance  is  entirely  dependent  upon  the  presence  of 
the  salivary  fluid;  being  completely  checked  when,  by  tying  the  oesophagus, 
that  fluid  is  prevented  from  passing  into  the  stomach.1  Saccharine  matters, 
being  readily  soluble  in  water,  do  not  require  the  agency  of  the  gastric  fluid, 
for  any  other  purpose  than  the  solution  of  their  investments,  whereby  they  are 
set  free;  and  it  does  not  appear  that  it  exerts  any  converting  power  upon  them. 
So,  again,  Oleaginous  matters  are  merely  reduced  to  a  state  of  fine  division,  and 
are  diffused  in  a  state  of  suspension  through  the  pulpy  chyme.  The  effect  of 
the  gastric  fluid  upon  the  several  kinds  of  Albuminous  matters  is  to  reduce 
them  to  a  state  of  complete  solution,  and  at  the  same  time  to  alter  their  chemi- 

1  See  Frerichs  in  "Wagner's  Haudworterbuch,"  Art.  "Verdauung." 


GASTRIC   DIGESTION.  427 

cal  properties,  so  that  they  for  the  most  part  lose  their  distinctive  attributes, 
and  are  brought  to  one  uniform  condition,  that  of  albuminose  (§  167),  which 
seems  to  be  the  state  best  adapted  for  subsequent  assimilation.  In  this  condi- 
tion they  seem  to  form  definite  combinations  with  the  solvent  fluid,  which  have 
received  the  name  of  peptones.  That  these  combinations,  however,  are  very 
different  from  mere  solutions  of  the  same  matters  in  acidulated  liquids,  has  been 
shown  by  the  experiments  of  M.  Bernard;  who  found  that,  on  injecting  the 
solution  of  albumen  in  very  dilute  hydrochloric  acid  into  the  general  circulation, 
the  liquid  speedily  passed  off  by  the  renal  secretion;  whilst  after  injecting  the 
solution  of  albumen  in  gastric  juice,  no  trace  of  this  could  be  detected  in  the 
urine.  Hence  it  seems  evident  that  the  converting  power  is  exerted  by  the 
pepsin,  or  peculiar  "  ferment"  of  the  gastric  fluid,  whilst  the  solvent  power  is  due 
to  the  acid;  a  conclusion  which  agrees  well  with  that  based  on  other  evidence 
(§  442).  It  appears  from  the  observations  of  MM.  Blondlot  and  Bernard, 
that  when  liquid  Albumen  is  taken  into  the  stomach,  it  does  not  undergo  com- 
plete coagulation  before  the  solvent  process  commences,  but  merely  becomes 
opalescent;  Casein,  on  the  other  hand,  is  completely  coagulated,  the  peculiar 
animal  principle  of  the  gastric  fluid  having  more  power  of  precipitating  it  than 
is  possessed  by  any  other  reagent  (§  22).  It  is  estimated  by  Lehmann,  that 
about  20  parts  of  fresh  gastric  juice  (of  the  dog)  are  required  to  dissolve  1  part 
of  albumen;  and  as  the  quantity  of  albuminous  matter  daily  consumed  by  Man 
may  be  estimated  at  between  3  and  4  oz.,  it  would  hence  appear  that  the  amount 
of  gastric  fluid  secreted  must  be  from  60  to  80  oz.  This  mode  of  calculation 
seems  to  afford  the  only  means  of  forming  even  an  approximative  idea  of  the 
quantity  of  fluid  poured  forth  from  the  walls  of  the  stomach.  Of  course  by  far 
the  larger  proportion  of  this  must  be  re-absorbed,  either  through  the  vessels  of 
the  stomach  itself,  or  through  those  of  the  intestinal  canal. — The  gastric  fluid 
has  also  a  special  solvent  power  for  Gelatinous  substances;  acting  upon  those 
which  would  have  otherwise  required  long  boiling  for  their  disintegration.  Here, 
too,  the  marked  difference  in  action  between  the  gastric  juice  and  a  merely  aci- 
dulous fluid,  has  been  demonstrated  by  M.  Bernard;  who  has  shown  that,  when 
a  piece  of  bone  is  submitted  to  the  latter,  its  mineral  portion  alone  is  affected 
by  it;  whereas  when  it  is  subjected  to  the  former,  the  gastric  juice  digests  the 
gelatin,  and  leaves  the  phosphates  and  carbonates  unaltered.  Here,  too,  a 
decided  transformation  is  effected  by  the  operation  of  the  gastric  fluid;  for  the 
gelatin  of  the  peptone  has  lost  its  power  of  gelatinizing,  and  is  not  precipitated 
by  chlorine. 

451.  This  action  of  the  Gastric  solvent  upon  the  azotized  constituents  of  the 
food,  is  dependent  upon  several  conditions.  One  of  the  most  important  of  these 
is  temperature.  A  heat  of  from  96°  to  100°  is  required  to  keep  up  the  solvent 
process,  which  is  retarded  according  to  the  depression  of  the  thermometer  below 
this  standard ;  so  that  at  the  ordinary  temperature  of  the  atmosphere  it  is  com- 
pletely suspended,  to  be  renewed,  however,  with  an  increment  of  heat.  On  the 
other  hand,  a  trifling  elevation  of  temperature  above  100°  occasions  a  decom- 
position in  the  gastric  juice,  which  entirely  destroys  its  solvent  power.  The 
next  condition,  which  specially  affects  the  time  required  for  the  process  of  solu- 
tion, is  motion.  This  does  not  act  mechanically,  by  way  of  "trituration,"  as 
was  once  supposed;  for  food  is  found  to  be  digested,  when  enclosed  in  metallic 
balls  perforated  to  admit  the  access  of  gastric  juice  to  their  interior.  But  it 
answers  the  purpose  of  thoroughly  subjecting  the  whole  of  the  alimentary 
bolus  to  the  agency  of  the  gastric  solvent,  by  bringing  each  part  successively 
into  contact  with  the  lining  membrane  of  the  stomach  from  the  surface  of  which 
the  fluid  is  effused.  The  removal  of  the  matters  already  reduced  or  dissolved, 
also,  has  a  most  important  effect  in  facilitating  the  solution  of  the  remainder. 
This  removal  is  due  in  part  to  the  absorption  of  the  matters  in  a  state  of  solu- 


428  OF   FOOD,    AND   THE   DIGESTIVE   PROCESS. 

tion,  into  the  bloodvessels  of  the  walls  of  the  stomach  (§  462) :  and  in  part  to 
the  successive  escape  of  the  reduced  portions  through  the  pyloric  orifice  (§  429). 
The  importance  of  the  previous  state  of  minute  division  and  incorporation  with 
aqueous  fluid,  in  promoting  the  action  of  the  gastric  solvent,  has  been  already 
dwelt  on  (§  424). 

452.  Although  the  Chyme,  or  product  of  gastric  digestion,  which  escapes 
through  the  pyloric  orifice  into  the  duodenum,  contains  much  azotized  matter 
in  a  state  of  actual  solution,  a  considerable  proportion  of  it  is  still  only  reduced 
and  mechanically  suspended;  and  the  solution  of  the  latter  is  continued  in  the 
intestinal  tube.  In  the  farinaceous  part  of  the  food,  moreover,  no  great  amount 
of  change  has  hitherto  been  effected;  and  the  sugar  which  has  been  generated 
by  the  agency  of  the  salivary  ferment,  is  probably  absorbed  into  the  bloodves- 
sels nearly  as  fast  as  it  is  formed.  In  the  condition  of  the  fatty  matters,  no 
important  change  is  perceptible,  except  such  as  results  from  the  solution  of  the 
membranes,  &c.,  that  enclosed  them.  Hence  we  see  that  the  process  of  Diges- 
tion, so  far  from  being  completed  in  the  stomach,  has  only  been  carried  one 
stage  further.  Soon  after  its  entrance  into  the  Duodenum,  the  chyme  is  sub- 
jected to  the  ac^ns  of  the  bile,  the  pancreatic  fluid,  and  that  secretion  from 
the  glandules  in  the  walls  of  the  intestine  itself  (probably  proceeding  chiefly, 
however,  from  the  glands  of  Brunner,  §  235),  which  is  known  under  the  name 
of  the  "succus  entericus." — Of  these,  the  Pancreatic  fluid  will  be  first  noticed. 
The  structure  of  the  Pancreas  closely  resembles  that  of  the  Salivary  glands 
(§  436) ;  for  it  consists  of  racemose  clusters  of  secreting  follicles,  which  form 
the  terminations  of  the  ramifying  divisions  of  the  duct;  each  cluster  with  its 
bloodvessels,  lymphatics,  nerves,  and  connecting  tissue,  forming  a  lobule ;  and 
the  separate  lobules  being  held  together  by  areolar  tissue,  as  well  as  by  the 
vessels  and  ducts.  Like  the  salivary  glands,  moreover,  its  development  com- 
mences by  a  sort  of  budding-forth  of  the  alimentary  canal  at  a  particular  spot, 
upon  which  a  mass  of  cells  has  previously  accumulated.  The  secretion  of  this 
gland  strongly  resembles  saliva  in  its  general  appearance,  being  clear  and  color- 
less, slightly  viscid,  and  alkaline  in  its  reaction;  it  contains,  however,  a  larger 
proportion  of  solid  matter,  its  specific  gravity  being  1008  or  1009;  and  the 
nature  of  its  animal  principle  is  not  precisely  the  same.  The  following  is  Prof. 
Frerichs'  analysis  of  the  pancreatic  fluid  of  the  Ass. 

Water 986.40 

Solids 13.60 

Fat     .         .         .       -W  i         .         .        s?.*, .*;•-...,' •»;•',-  v  0.26 

Alcohol-Extract.         .        v  •      ..;  ,..;.>::,r  .-,  \  <»«».«•..*  *,?.•.•<»•».•; n  0.15 

Water-Extract,  albuminous     k-  •  ,,, ;    rf         .         .        +  ..,;  y,  3.09 

(Chlorides     ) 

Phosphates  I      .       '  .  "*    .         .  8.90 
Sulphates    ) 
Carbonate  and  phosphate  of  lime  and  magnesia    .         .         .       .1.20 


1000.00          13.60 

The  albuminous  "ferment"  is  not  perfectly  coagulable  by  heat,  and  when  pre- 
cipitated by  alcohol  it  redissolves  readily  in  water;  it  is  precipitated  by  sul- 
phuric, nitric,  and  concentrated  hydrochloric  acid,  and  by  the  metallic  salts ; 
and  when  thrown  down  by  these,  or  by  heat,  it  is  redissolved  by  alkalies.  It 
is  also  precipitated  by  acetic  acid;  but  it  slowly  redissolves  in  an  excess  of  the 
reagent,  and  on  the  application  of  heat ;  and  from  this  solution  it  is  precipitated 
by  ferrocyanide  of  potassium.  When  boiled  with  ammonia,  it  assumes  an  in- 
tense yellow  color.  The  readiness  with  which  this  substance  undergoes  change 
is  indicated  by  the  rapidity  with  which  the  pancreatic  fluid  passes  into  decom- 


INTESTINAL   DIGESTION.  429 

position  ;  for,  even  after  a  few  hours'  exposure  to  the  air,  it  gives  off  a  decidedly 
putrid  odor.  Like  ptyalin,  this  peculiar  constituent  of  the  pancreatic  fluid 
possesses  the  power  (though  in  a  less  degree)  of  converting  starch  into  sugar ; 
there  can  be  no  doubt,  therefore,  that  it  is  subservient  to  the  continued  diges- 
tion of  the  farinaceous  part  of  the  food,  during  its  passage  through  the  small 
intestines.  It  shares  this  office,  however,  with  the  "  succus  enterieus,"  which 
has  been  shown  by  Frerichs  and  Hiibbenet  to  be  also  possessed  of  this  convert- 
ing power. — It  has  recently  been  affirmed  by  M.  Cl.  Bernard,  and  strong  evi- 
dence has  been  adduced  by  him  in  support  of  his  statement,  that  the  essential 
purpose  of  the  pancreatic  fluid  is  to  promote  the  absorption  of  fatty  matters, 
by  reducing  them  to  the  state  of  an  emulsion,  which  is  capable  of  finding  its 
way  into  the  lacteals.1  That  this  fluid  possesses  the  emulsifying  power  in  a 
peculiar  degree,  may  be  considered  as  having  been  fully  demonstrated  by  his 
experiments;  for  on  mixing  it  with  oil,  butter,  or  any  variety  of  fat,  at  a  tem- 
perature sufficiently  high  to  render  the  fatty  substance  liquid,  and  then  stirring 
the  mixture  for  a  few  minutes,  an  emulsion  is  produced  bearing  a  strong  resem- 
blance to  chyle.  This  emulsion  does  not  cease  to  present  its  peculiar  aspect, 
although  left  standing  for  some  time;  whereas  although  bile,  saliva,  gastric 
juice,  blood- serum,  and  other  animal  fluids,  have  a  certain  emulsifying  power, 
yet  after  a  short  time  the  oil-particles  run  together  again,  almost  as  if  they  had 
been  merely  shaken  up  with  water.  Further,  it  is  asserted  by  Bernard,  that  in 
the  Rabbit  (in  which  the  pancreatic  duct  discharges  itself  some  inches  lower 
down  in  the  intestine  than  does  the  bile-duct),  when  fatty  matters  have  been 
introduced  into  the  alimentary  canal,  they  undergo  no  considerable  change,  until 
they  have  passed  the  orifice  of  the  pancreatic  duct ;  an  oily  emulsion  being  then 
for  the  first  time  found  in  the  intestinal  canal ;  and  the  contents  of  those  absorb- 
ents only  having  the  opaque  whiteness  of  chyle,  which  originate  in  the  intes- 
tinal villi  below  that  orifice.  So,  again,  M.  Bernard  affirms  that  by  putting  a 
ligature  round  the  pancreatic  duct,  the  digestion  of  oleaginous  matter  is  so  com- 
pletely prevented,  that  it  is  found  unchanged  in  the  lower  part  of  the  intestinal 
tube,  and  no  opalescent  chyle  is  found  in  the  lacteals.  This  position  is  further 
strengthened  by  the  fact  ascertained  by  clinical  observation,2  that  there  is  a  close 
relation  between  disease  of  the  pancreas,  and  the  discharge  of  fatty  matters  per 
anum  (§  198). — It  has  been  shown,  however,  by  the  experimental  researches  of 
Frerichs,  Lehmann,  Lenz,3  and  others,  that  the  statements  of  M.  Bernard  are 
too  exclusive  in  their  character;  for  that  the  digestion  and  absorption  of  fatty 
matters  will  take  place  after  the  pancreatic  duct  has  been  tied  (sufficient  time 
having  been  given  for  the  evacuation  of  any  pancreatic  fluid  which  may  have  been 
in  the  alimentary  canal  previously  to  the  operation),  and  even  in  the  lower  part 
of  the  small  intestine,  into  which  these  substances  have  been  conveyed  by  in- 
jection, after  it  has  been  completely  separated  by  a  ligature  from  the  upper  part 
into  which  the  pancreatic  fluid  has  been  poured.  It  further  appears  from  their 
experiments,  that  a  mixture  of  the  pancreatic  fluid  with  bile  and  the  "  succus 

1  "Archiv.  Gener.  de  Med.,"  torn.  xix. — It  lias  been  assumed  by  Frerichs,  Lenz,  and 
other  objectors  to  M.  Bernard's  views,  that  he  maintains  that  the  pancreatic  fluid  saponi- 
fies the  neutral  fatty  matters  taken  in  as  food,  converting  them  into  fatty  acids  and  glyce- 
rine whilst  yet  within  the  intestinal  canal.     It  is  no  doubt  true  that  M.  Bernard  considers 
that  some  such  transformation  takes  place  in  the  body,  before  the  fatty  matter  is  ultimately 
disposed  of;  but  he  constantly  speaks  of  the  emulsifying  power  as  the  peculiar  attribute  of 
the  pancreatic  fluid,  and  only  asserts  that  saponification  takes  place  in  artificial  digestion, 
when  the  fluid  is  left  for  some  time  in  contact  with  fatty  substances ;   so  that  the  Author 
is  inclined  to  regard  the  objections  above  alluded  to,  as  having  arisen  from  a  misappre- 
hension of  M.  Bernard's  meaning.     (See  also  Dr.  Donaldson's  account  of  M.  Bernard's 
discoveries,  in  the  "Amer.  Journ.  of  Med.  Sci.,"  Oct.  1851.) 

2  See  Dr.  Bright's  researches  on  this  point,  in  "  Med.-Chir.  Trans.,-"  vol.  xviii. 
"De  Adipis  Concoctione  et  Absorption,"  Dorpat,  1850. 


430  OF   FOOD,    AND   THE   DIGESTIVE   PROCESS. 

entericus"  possesses  a  more  energetic  emulsifying  power  than  the  first  of  these 
fluids  alone;  and  it  seems  probable  that,  as  in  the  conversion  of  starch,  so  in 
the  emulsification  of  fat,  the  intestinal  fluid  performs  a  very  important  part. 
It  would  not  seem  unlikely  that  the  qualities  of  these  fluids  (like  those  of  the 
saliva)  may  vary  in  different  animals;  and  that  the  emulsifying  power  may  be 
limited  in  the  rabbit,  or  nearly  so,  to  the  pancreatic  fluid,  the  quantity  of  fat 
which  its  natural  food  contains  being  small;  whilst  in  the  carnivorous  animals, 
whose  natural  food  is  more  oleaginous,  the  provision  for  the  digestion  of  fatty 
matters  may  be  more  extensive. — Of  the  amount  of  pancreatic  fluid  which  is 
daily  secreted  by  Man,  we  have  no  other  data  for  forming  an  estimate  than 
those  afforded  by  the. observations  of  Frerichs;  who  collected  from  an  ass,  in" 
45  minutes,  387?  grains,  and  from  a  large  dog,  in  25  minutes,  46  grains.  These 
amounts,  however,  were  poured  forth  while  food  was  in  the  stomach  and  digestion 
was  going  on;  and  it  is  probable  that,  at  other  times,  the  secreting  process  is 
nearly  or  entirely  suspended. 

453.  The  Duodenum  receives  not  only  the  Pancreatic,  but  also  the  Biliary 
secretion ;  and  from  the  constancy  with  which  this  fluid  is  poured  into  the  upper 
part  of  the  intestinal  tube,  or  even  into  the  stomach  itself,  in  all  animals  which 
have  any  kind  of  hepatic  apparatus,1  it  seems  a  legitimate  inference  that  this 
secretion  is  not  purely  excrementitious,  but  serves  some  important  purpose  in 
the  digestive  process.  It  is  not  easy,  however,  to  state  with  precision  what  this 
purpose  is.  The  result  of  many  of  the  experiments  which  have  been  made  to 
•determine  it,  are  vitiated  by  the  fact,  that  the  pancreatic  duct  in  most  cases 
discharges  itself  into  the  intestinal  tube  at  the  same  point  with  the  hepatic,  and 
has  thus  been  frequently  involved  in  operations  performed  upon  it. — As  the 
most  important  constituents  of  Bile  have  been  already  described  (§§  67 — 71), 
and  as  the  agency  of  the  Liver  as  an  assimilating  and  depurating  organ  will  be 
more  appropriately  considered  elsewhere  (CHAPS,  vin.  and  xn.),  we  shall  here 
limit  ourselves  to  the  consideration  of  what  may  be  regarded  as  the  best  esta- 
blished facts  in  regard  to  the  uses  of  the  biliary  secretion  in  the  digestive  pro- 
cess. When  its  action  is  tested  out  of  the  body,  by  mingling  it  with  the 
different  constituents  of  food,  it  is  found  to  exert  no  change  upon  starchy  sub- 
stances whilst  it  is  fresh ;  though,  when  in  a  state  of  incipient  decomposition, 
it  acts  upon  them  as  other  animal  substances  do.  It  has  no  action  upon  cane 
sugar,  until  it  has  stood  a  considerable  length  of  time ;  but  then  it  converts  it 
into  lactic  acid.  This  change  it  speedily  exerts,  as  do  nearly  all  other  animal 
substances,  upon  grape  sugar.  It  has  no  action  on  albuminous  substances,  even 
when  acidulated.  And,  although  it  will  form  an  emulsion  with  oleaginous 
matter,  yet  the  emulsification  is  less  complete  than  that  which  is  effected  by  the 
pancreatic  fluid  alone.3  Hence  it  appears  to  be  deficient  in  anything  at  all 
similar  to  the  peculiar  ferments  of  the  saliva,  gastric  juice,  and  pancreatic 
secretion ;  and  its  oflice  in  digestion  must  be  of  a  different  character  from  that 
of  either  of  those  fluids.  The  nature  of  this  oflice  may  be  partly  judged  of 
from  what  takes  place  when  fresh  bile  is  mingled  with  the  product  of  gastric 
digestion.  The  acid  reaction  of  the  latter  is  neutralized  by  the  alkali  of  the 
former,  and  a  sort  of  precipitation  takes  place  (as  was  originally  noticed  by  Dr. 
Beaumont),  in  which  certain  constituents  of  the  bile  fall  down,  and  in  which 
also  (according  to  M.  Bernard)  the  albuminous  matters  that  have  been  dissolved 
and  not  yet  absorbed,  are  for  a  time  rendered  insoluble,  leaving  the  saccharine 
matters  in  solution,  and  the  oleaginous  floating  on  the  top.  The  admixture  of 

1  See  "Princ.  of Phys.,  Gen.  and  Comp.,"  Am.  Ed.,\%  583— 588.— The  simplest  con- 
dition of  the  Liver,  such  as  we  meet  with  in  the  higher  lladiata,  and  in  the  lower  Articu- 
lata  and  Mollusca,  consists  in  a  series  of  follicles  lodged  in  the  walls  of  the  stomach  and 
of  the  upper  part  of  the  intestinal  tube. 

2  Dr.  Bence  Jones,  in  the  "Medical  Times,"  July  5,  1851. 


INTESTINAL   DIGESTION.  431 

the  bile  with  the  chyme  seems  further  to  have  the  effect  of  checking  destructive 
chemical  changes  in  its  composition.  For  M.  Bernard  found  that  when  two 
similar  pieces  of  meat  had  been  immersed  for  three  months,  one  in  a  bottle  of 
gastric  juice  alone,  the  other  in  a  mixture  of  gastric  juice  and  bile,  a  strong 
ammoniacal  odor  resulting  from  decomposition  was  emitted  from  the  former, 
whilst  the  latter  was  •  pure  and  free  from  any  smell  whatever.  And  it  was  re- 
marked by  MM.  Tiedemann  and  Gmelin,  that  when  the  bile  was  prevented 
from  passing  into  the  alimentary  canal,  the  contents  of  the  latter  were  more 
fetid  than  usual.  Moreover,  it  is  found  that  the  admixture  of  bile  with  fer- 
menting substances  checks  the  process  of  fermentation ;  and  M.  Bernard  has 
shown  by  ingeniously  contrived  experiments,1  that  this  antagonistic  power  is 
exerted  also  in  the  living  body.  Hence  we  can  understand  how  the  reflux  of 
bile  into  the  stomach  should  seriously  interfere  with  the  process  of  gastric 
digestion ;  and  how,  when  there  is  a  deficient  secretion  of  bile,  or  more  food  is 
swallowed  than  the  bile  provided  for  it  can  act  upon,  or  the  character  of  the 
biliary  secretion  itself  has  undergone  any  serious  perversion,  there  should  be  a 
much  larger  amount  of  the  putrefactive  fermentation  than  is  normal,  as  indi- 
cated by  an  evolution  of  flatus,  and  very  frequently  by  diarrhoea.  Further,  the 
want  of  proper  neutralization  of  the  gastric  fluid  will  cause  the  continuance  of 
acidity  in  the  contents*  of  the  intestinal  canal,  which  in  its  turn  induces  a  state 
of  irritation  of  its  mucous  membrane,  and  a  perversion  of  its  secretions  :  and  it 
is  one  of  the  beneficial  results  of  "  alterative"  medicines,  employed  to  remedy 
this  condition,  that,  by  augmenting  the  secretion  of  bile,  they  tend  to  reproduce 
a  state  of  neutrality  in  the  contents  of  the  alimentary  canal.  Moreover,  the 
presence  of  a  proper  quantity  of  bile  in  the  intestine  appears  to  promote  the 
secreting  action  of  the  intestinal  glandulae,  and  also  to  contribute  to  maintain 
the  peristaltic  movement  of  the  walls  of  the  canal ;  this  appears  alike  from  the 
tendency  to  constipation,  which  is  usually  consequent  upon  deficiency  of  the 
secretion,  and  from  the  diarrhoea  which  proceeds  from  its  excess ;  and  is  con- 
firmed by  the  purgative  properties  which  inspissated  ox-gall  has  been  found  to 


454.  Notwithstanding  all  its  uses,  however,  it  must  be  admitted  that  the  pre- 
vention of  the  discharge  of  bile  into  the  alimentary  canal  is  not  attended  with 
the  deleterious  results  which  might  have  been  anticipated  from  it ;  for  it  has 
been  found  by  the  experiments  of  Schwann,  Blondlot,  and  Bernard,  that  if  the 
bile-duct  be  divided,  and  a  tube  be  inserted  in  it  in  such  a  manner  as  to  convey 
away  the  secretion  through  a  fistulous  orifice  in  the  abdominal  parietes,  the 
animals  thus  treated  may  live  for  weeks,  months,  or  even  years,2  although  they 
usually  die  at  last  with  signs  of  inanition.  Of  the  quantity  of  bile  daily  poured 
into  the  alimentary  canal  of  Man,  we  have  no  other  mode  of  forming  an  esti- 
mate, than  by  observing  the  quantity  poured  out  from  the  bile-ducts  of  animals 
in  such  experiments  as  those  just  cited.  Blondlot  found  that  a  dog  in  which  he 
had  established  a  fistulous  opening  for  the  discharge  of  the  bile,  secreted  from 
40  to  50  grammes  in  the  twenty-four  hours;  whence  he  inferred  that  an  adult 
man  secretes  about  200  grammes,  or  7  oz.  The  carefully-conducted  observations 
of  Bidder  and  Schmidt3  indicate  that  the  rate  of  secretion  is  by  no  means  uni- 
form, but  that  it  bears  a  certain  relation  to  the  digestive  process ;  the  quantity 
poured  forth  in  a  given  time  being  greatest  about  10  or  12  hours  after  a  full 
meal,  and  then  diminishing  until  it  reaches  its  minimum,  for  which  about  as 

1  "Amer.  Journ.  of  Med.  Sci.,"  Oct.  1851,  p.  351. 

2  At  the  meeting  of  the  French  Academy,  June  23, 1851,  M.  Blondlot  gave  the  history, 
and  an  account  of  the  post-mortem  examination,  of  a  Dog  that  had  lived  five  years  without 
the  passage  of  any  bile  into  the  intestinal  tube. 

3  See  Prof.  Lehmann's  "Lehrbuch  der  physiologischen  Chemie,"  band  ii.  p.  72. 


432        OP  FOOD,  AND  THE  DIGESTIVE  PROCESS. 

many  more  hours  are  required.  Thus  a  Cat,  two  hours  after  a  full  meal  of  flesh, 
secreted  at  the  rate  of  7.5  grains  of  bile  per  hour;  at  the  4th  hour,  9.7  grains; 
at  the  6th  hour,  11.6  grains;  at  the  8th  hour,  12.7  grains;  and  at  the  10th 
hour,  13  grains.  From  the  10th  to  the  24th  hour,  the  secretion  diminished  at 
the  rate  of  4.10ths  of  a  grain  per  hour,  until  it  reached  the  lowest  of  the  above 
amounts.  The  secretion  is  considerably  diminished  when  food  is  withheld  for 
some  time ;  the  quantity  poured  out  after  ten  days'  starvation  being  only  about 
one-eighth  of  what  it  is  when  at  its  maximum.  Still  it  is  obvious  that,  although 
its  rate  is  thus  greatly  influenced  by  the  stage  of  the  digestive  process  (which  is 
the  less  to  be  wondered  at,  when  it  is  remembered  that  the  secretion  is  formed 
from  blood  that  is  charged  with  newly-absorbed  and  imperfectly  assimilated 
matters),  the  excrementitious  character  of  the  secretion  requires  that  its  elimi- 
nation shall  be  constantly  going  on  to  a  certain  degree ;  but  a  receptacle  is  pro- 
vided in  Man,  as  in  most  others  among  the  higher  animals  whose  digestion  is 
performed  at  intervals,  for  the  storing-up  of  the  fluid  until  it  can  be  usefully 
employed  in  that  process.  The  intestinal  orifice  of  the  ductus  choledochus  is 
closed  by  a  sort  of  sphincter ;  and  the  fluid  secreted  during  the  intervals  of 
digestion,  not  being  propelled  with  a  force  sufficient  to  dilate  this,  flows  back  into 
the  gall-bladder,  which  dilates  to  receive  it.  The  presence  of  food  in  the  duo- 
denum seems  to  excite  the  walls  of  the  gall-bladder  and  of  the  biliary  ducts 
(which  contain  a  large  quantity  of  smooth  muscular  fibre,  §  305)  to  a  contrac- 
tion sufficiently  powerful  to  propel  their  contents  into  the  intestine,  in  spite  of 
the  opposition  of  the  sphincter ;  but  whether  this  takes  place  through  a  reflex 
action  of  the  nervous  system,  or  through  the  direct  stimulation  of  the  muscular 
coat  of  the  duct  by  the  passage  of  alimentary  matters  over  its  orifice,  we  have 
at  present  no  means  of  satisfactorily  determining.  It  will  be  recollected  that 
the  gall-bladder  is  usually  found  distended  with  bile,  in  cases  of  death  from 
starvation  (§  417),  notwithstanding  the  diminution  in  the  amount  actually 
secreted. 

455.  The  fluid  of  the  Small  Intestines,  which  is  compounded  by  the  inter- 
mixture of  the  biliary  and  pancreatic  secretions,  with  the  salivary  and  gastric 
fluids,  and  with  the  secretion  of  the  intestinal  glandulae,  appears  to  possess  the 
very  peculiar  power  of  dissolving  or  of  reducing  to  an  absorbable  condition, 
alimentary  substances  of  every  class ;  thus  possessing  more  of  the  character  of 
a  "universal  solvent/'  than  either  of  these  secretions  has  in  its  separate  state. 
It  completes  the  conversion  of  starchy  into  saccharine  matter ;  and  thus  enables 
the  former  to  supply  the  blood  with  an  important  pabulum  for  the  combustive 
process,  which  is  at  once  absorbed  into  the  bloodvessels.  It  emulsifies  the 
oleaginous  matter,  and  thus  renders  it  capable  of  being  introduced  into  the 
lacteals.  And  it  not  only  restores  to  the  state  of  solution  the  albuminous  com- 
pounds, which  may  have  been  precipitated  by  the  addition  of  bile  to  the  product 
of  gastric  digestion;  but  it  also  exerts  a  powerful  solvent  influence  upon  albu- 
minous substances  which  have  not  been  submitted  to  the  previous  agency  of 
the  gastric  fluid  (as  has  been  shown  by  experimentally  introducing  pieces  of 
meat,  through  a  fistulous  orifice,  directly  into  the  duodenum),  and  it  thus  com- 
pletes the  solvent  process  which  had  been  very  far  from  perfected  in  the  sto- 
mach.1 What  is  the  precise  share,  however,  of  each  of  these  secretions  in 
producing  this  composite  result,  cannot  be  stated  with  any  degree  of  certainty; 
but  it  seems  probable  that  the  secretions  of  the  intestinal  walls  have  a  very 
definite  share  in  it. — It  is  obvious  that  the  amount  of  each  kind  of  alimentary 
substance  that  can  be  thus  prepared  for  absorption  in  a  given  time,  will  vary 

.- 

1  See  the  account  of  M.  Cl.  Bernard's  researches  in  the  "Amer.  Journ.  of  Med.  Sci.," 
Oct.  1851,  p.  356;  Zander,  "De  Succo  Enterico,"  inaug.  diss.,  Dorpat,  1850;  Frerichs, 
Art.  Verdauung,  in  "Wagner's  Handworterbuch;"  and  Liebig's  "  Annalen  der  Chemie,"  &c. 


INTESTINAL   DIGESTION. 


433 


with  the  amount  of  the  secretion  by  whose  agency  this  preparation  is  specially 
affected ;  and  as  there  are  many  indications  that  the  quantity  of  each  that  is 
taken  up  in  absorption  is  limited,  and  that  it  bears  a  relation  to  the  wants  of 
the  system,  it  is  probable  that  the  amount  of  the  solvent  or  reducing  fluid  that 
is  secreted  by  each  glandular  apparatus  is  regulated  (as  we  have  seen  it  to  be 
in  the  case  of  the  gastric  juice,  §  444)  by  the  demand  set  up  by  the  nutrient 
operations,  rather  than  by  the  amount  of  alimentary  matter  that  is  waiting  to 
be  digested. — The  processes  of  digestion  and  conversion  are  probably  continued 
during  the  entire  transit  of  the  alimentary  matter  along  the  small  intestine, 
and  at  the  same  time  the  products  of  that  conversion  are  gradually  being  with- 
drawn by  absorbent  action ;  so  that,  by  the  time  it  reaches  the  caecum,  the 
undigested  residue  contains  little  else  than  the  innutritions  or  insoluble  compo- 
nents of  the  food,  together  with  the  excrementitious  portion  of  the  bile  and  of 
other  secretions.  Up  to  this  time,  the  contents  of  the  canal  have  an  alkaline 
reaction;  but  in  the  caecum  they  again  become  acid;  and  it  has  been  supposed 
that  this  change  depends  upon  the  secretion  of  a  fluid  analogous  to  the  gastric 
juice,  by  the  large  and  numerous  tubular  glands  contained  in  the  parietes  of  this 

£t,  whereby  the  albuminous  matters  still  undigested  might  be  more  completely 
solved.     This  supposition  appeared  to  derive  weight  from  the  fact,  that  the 
caecum  is  peculiarly  large  in  most  Herbivorous  animals,  the  "  appendix  vermi- 
formis"  being  also  of  greatly  increased  dimensions,  and  sometimes  double.     But 


Fig.  127. 


Fig.  128. 


A  section  of  the  small  Intestine  containing  some 
of  the  glands  of  Peyer,  as  shown  under  the  micro- 
scope. These  glands  appear  to  be  small  lenticular 
excavations,  containing,  according  to  Boehm,  a  white, 
milky,  and  rather  thick  fluid,  with  numerous  round 
corpuscles  of  various  sizes,  but  mostly  smaller  than 
blood-globules.  The  meshes  seen  in  the  cut  are  the 
ordinary  tripe-like  folds  of  the  mucous  coat,  and  not 
the  venous  texture  spoken  of  under  the  follicles. 


Portion  of  one  of  the  patches  of  Peyer's  Glands, 
from  the  end  of  the  Ileum,  moderately  magnified ; 
the  villi  are  also  displayed. 


from  the  experiments  and  observations  of  Blondlot,  it  seems  probable  that  the 
acid  of  the  caecum  is  rather  a  product  of  the  transformation  of  saccharine  sub- 
stances in  the  alimentary  canal,  than  a  secretion  from  its  walls.1  Still,  as  this 
lactic  acid  has  a  solvent  power  for  albuminous  matters,  which  is  equal,  or  nearly 


28 


1  See  his  "Traite"  analytique  de  la  Digestion,"  p.  103. 


434 


OF   FOOD,    AND    THE   DIGESTIVE   PROCESS. 


so,  to  that  exerted  by  hydrochloric  acid,  it  is  by  no  means  impossible  that  it 
may  be  subservient  to  the  completion  of  the  digestive  process  in  the  case  in 
question ;  since,  the  larger  the  proportion  of  the  aliment  composed  of  saccha- 
rine matters,  the  greater  will  be  the  importance  of  a  thorough  extraction  of  its 
albuminous  constituents. 

456.  The  walls  of  the  lower  part  of  the  Small  Intestine  are  beset  with  ele- 
vated patches,  that  are  formed  by  the  aggregation  of  the  bodies  known  as  the 
"Peyerian  glandulae;"  bodies  of  a  similar  kind,  however,  also  occur  separately, 
and  are  then  known  as  the  "glandulse  solitariae."  The  "  glands  of  Peyer," 
when  examined  in  a  healthy  mucous  membrane,  present  the  appearance  of  cir- 
cular, white,  slightly  raised  spots,  about  a  line  in  diameter;  over  which  the 
membrane  is  usually  less  set  with  villi,  and  very  often  entirely  free  from  them. 
Each  of  these  white  spots,  of  which  a  large  number  are  contained  in  the 
agminated  glands,  is  surrounded  by  a  zone  of  openings  like  those  of  the  follicles 
of  Lieberkiihn,  which  lead  (as  do  those)  into  tubular  caeca  (Figs.  127,  128). 

Not  unfrequently,  however, 
the  centre  of  the  spot  exhibits 
a  very  definite  opening,  which 
may  be  compared  to  the  pupil 
of  the  eye;  and  this  opening, 
though  formerly  supposed  to 
be  abnormal,  appears  from  the 
observations  of  Prof,  Krause1 
and  Allen  Thomson3  to  be 
the  normal  condition  of  the 
body  at  a  certain  stage  of  its 
development.  In  the  Pig,  on 
which  the  greater  number  of 
Dr.  A.  Thomson's  observations 
were  made,  some  patches  often 
present  no  openings,  whilst  in 
others  almost  all  the  cavities 
are  open  and  empty;  and  in 
a  third  set,  open  and  closed 
vesicles  are  irregularly  dis- 
posed in  the  same  patch  (Fig. 
open  vesicles  were  observed 


A.  Portion  of  a  patch  of  Peyerian  Qlandulce  from  the  ileum  of 
the  Pig,  as  seen  from  the  deep  surface,  the  serous,  muscular,  and 
areolar  coats  having  heen  dissected  off;  the  darker  vesicles  are 
open  and  empty,  the  paler  closed  and  full ;  magnified  3  diame- 
ters. B.  Two  of  these  vesicles,  viewed  from  the  inner  surface  of 
the  intestine,  one  of  them  closed  and  full,  the  other  open  and 
empty,  with  villi  and  apertures  of  mucous  follicles  in  their  neigh- 
borhood ;  magnified  15  diameters. 


Fig.  130. 


129).      The 


Vertical  section  of  two  of  the  Peyerian  Glan- 
dulce  from  the  ileum  of  the  Pig,  one  of  them 
closed  and  full,  the  other  open  and  empty,  with 
their  neighboring  villi ;  magnified  15  diameters : 
a,  cellular  contents  of  the  veskle;  magnified 
250  diameters. 


more  frequently  in  the  ileum  than  in  the 
upper  part  of  the  intestine;  and  it  ap- 
peared to  be  in  those  parts  of  the  intes- 
tine which  contained  the  more  fluid,  dark- 
colored,  and  bilious  matter,  that  the  open 
vesicles  were  almost  invariably  found; 
while  in  those  parts  of  the  gut  which 
contained  a  light-colored  chymous  or  chy- 
lous  mass,  which  were  more  contracted, 
and  in  which  the  coats  appeared  thickened 
by  the  imbibition  of  chyle,  the  vesicles  were 
all  closed  and  full  of  their  usual  contents. 
These  consist  of  minute  granular  cells, 
mixed  with  molecules  of  various  sizes  (Fig. 
130) ;  and  it  has  not  seemed  an  unreason- 
able supposition,  that  each  of  these  bodies 


1  "Muller's  Archiv.,"  1837  and  1839. 

2  "Annals  of  Anatomy  and  Physiology,"  No.  1,  p.  35. 


INTESTINAL  DIGESTION.  435 

might  be  regarded  as  a  distinct  glandular  vesicle,  which  dehisces  and  discharges 
its  contents,  when  these  are  prepared  for  being  set  free;  and  that  it  is  then  suc- 
ceeded by  a  new  vesicle  developed  de  novo  from  a  parent-cell  (§  235). — A  new 
view  of  the  character  of  the  Peyerian  bodies,  however,  has  lately  been  put  forth 
by  Briicke ;  who  affirms  that  they  are  always  closed  in  their  normal  condition, 
and  maintains  that  they  are  appendages  to  the  absorbent  system,  its  trunks 
being  filled  by  injections  made  to  penetrate  from  them,  and  their  cellular  con- 
tents being  precisely  conformable  in  aspect  and  character  to  those  of  the  mesen- 
teric  glandulae.1  It  has  been  further  demonstrated  by  Prof.  Frei,  that  the 
interior  of  each  vesicle  is  traversed  by  a  set  of  capillary  vessels,  which  radiate 
from  the  periphery  towards  the  centre,  and  then  return  by  loops  ;a  a  structure 
which  is  found  also  in  the  "  Malpighian  bodies"  of  the  Spleen,  the  vesicles  of 
the  Thynius,  &c.  Hence,  these  anatomists  urge  that  the  so-called  "  Peyerian 
glandulse"  must  be  regarded  as  instruments  for  the  elaboration  of  the  chyle, 
which  is  conveyed  to  them  by  the  very  delicate  absorbents  that  originate  in  the 
villi,  and  is  carried  off  by  the  larger  trunks  which  then  pass  into  the  mesen- 
tery.3— The  walls  of  the  Large  Intestine  contain  a  considerable  number  of 
glandulae,  which  closely  resemble  the  "glandulae  solitaries"  of  the  higher  part 
of  the  canal;  these,  however,  are  so  much  more  frequently  open  than  closed, 
that  the  latter  condition  was  not  recognized  until  pointed  out  by  Dr.  Baly.4  It 
can  scarcely  be  doubted  that  these  are  secreting  organs,  destined  to  pour  the 
product  of  their  activity  into  the  alimentary  canal;  but  whether  this  product 
be  the  peculiar  mucus  with  which  the  coats  of  the  large  intestine  are  covered, 
or  consist  of  the  proper  fecal  matter,  or  be  something  different  from  either,  has 
not  yet  been  determined. 

457.  The  undigested  residue  of  the  food,  mingled  with  the  products  of  secre- 
tion that  have  been  poured  into  the  alimentary  canal,  gradually  acquires,  in  the 
Large  Intestine,  the  ordinary  consistency  of  feces,  through  the  continuance  of 
the  absorbent  process,  whereby  the  superfluous  fluid  is  removed.  The  condition 
of  the  undigested  residue  has  been  particularly  studied  by  Dr.  Rawitz,  who  ex- 
amined microscopically  the  products  of  the  artificial  digestion  of  different  kinds 
of  aliment,  and  the  contents  of  the  feces  of  animals  that  had  eaten  the  same 
articles.  "The  general  results  of  his  examinations,  as  regards  animal  food, 
show  that  the  muscular  tissue  breaks  up  into  its  constituent  fasciculi,  and  that 

1  See  his  Memoir  "Ueber  den  Bau  und  die  physiologische  Bedeutung  der  Peyerischen 
Drvisen,"  in  " Denkschriften  der  kaiserlichen  Akademie  der  Wissenschaften,"  Wien,  1850; 
and  an  abstract  of  it  in  the  "Edinb.  Monthly  Journ.,"  Nov.  1850. 

2  See  Prof.  Kolliker's  " Mikroskopische  Anatomic,"  band  ii.  §  171. 

3  In  the  above  statements,  the  Author  has  considered  it  preferable  to  place  before  his 
readers  the  results  of  actual  observations,  rather  than  to  indulge  in  any  hypothesis  of  his 
own.     Taking  for  granted  the  doctrine  generally  admitted  amongst  modern  anatomists 
and  physiologists,  that  the  Peyerian  vesicles  are  glandules  discharging  their  product  into 
the  intestinal  tube — combining  this  with  the  doctrine,  of  which  also  there  appeared  to  his 
mind  to  be  adequate  evidence,  that  the  proper  fecal  matter  is  a  secretion  sui  generis,  and 
not  a  mere  product  of  the  decomposition  of  the  contents  of  the  alimentary  canal — and 
taking  into  account  the  correspondence  in  position  between  the  principal  aggregations  of 
Peyerian  glandulse  and  the  assumption  of  the  fecal  character  by  the  undigested  residue  of 
the  food — he  had  considered  himself  justified  in  advancing  it  as  probable,  that  the  Peyerian 
glandulae  are  the  special  instruments  for  the  elimination  of  decomposing  matter  from  the 
blood,  and  that  it  is  their  function  to  discharge  this  excrementitious  product  into  the 
alimentary  canal.     And  the  tendency  to  ulceration  of  these  follicles,  which  shows  itself  in 
typhoid  fever,  and  other  "poison-diseases,"  was  cited  by  Dr.  C.  J.  B.  Williams  ("Principles 
of  Medicine,"  p.  245,  3d  Am.  Ed.}  in  confirmation  of  this  view.     Having  himself  repeatedly 
met  with  the  follicles  in  the  open  condition,  like  Dr.  Allen  Thomson,  and  having  been  well 
convinced  that  this  is  a  normal  state,  he  finds  it  difficult  to  receive  the  doctrine  of  Briicke 
(espoused  though  it  has  been  by  Prof.  Kolliker)  as  expressing  the  whole  truth  on  this 
subject,  which  is  one  that  is  well  deserving  of  further  investigation. 

«  "Medical  Gazette,"  March,  1847. 


436  OF   FOOD,    AND   THE   DIGESTIVE   PROCESS. 

these  again  are  divided  transversely;  gradually  the  transverse  stride  become  in- 
distinct and  then  disappear ;  and  finally  the  sarcolemma  seems  to  be  dissolved, 
and  no  trace  of  the  tissue  can  be  found  in  the  chyme,  except  a  few  fragments 
of  fibres.  These  changes  ensue  most  rapidly  in  the  flesh  of  fish  and  hares,  less 
rapidly  in  that  of  poultry  and  other  animals.  The  fragments  of  muscular  tissue 
which  remain  after  the  continued  action  of  the  digestive  fluid,  do  not  appear  to 
undergo  any  alteration  in  their  passage  through  the  rest  of  the  intestinal  canal ; 
for  similar  fragments  may  be  found  in  feces,  even  twenty-four  hours  after  the 
introduction  of  the  meat  into  the  stomach.  The  cells  of  cartilage  and  fibro- 
cartilage,  except  those  of  fish,  pass  unchanged  through  the  stomach  and  intes- 
tines, and  may  be  found  in  the  feces.  The  interstitial  tissues  of  these  structures 
are  converted  into  pulpy  textureless  substances  in  the  artificial  digestive  fluid, 
and  are  not  discoverable  in  the  feces.  Elastic  fibres  are  unchanged  in  the 
digestive  fluid.1  Fatty  matters  are  also  unchanged;  fat-cells  are  sometimes 
found  quite  unaltered  in  the  feces ;  and  crystals  of  cholesterin  may  usually  be 
obtained  from  feces,  especially  after  the  use  of  pork-fat. — As  regards  vegetable 
substances,  Dr.  Rawitz  states  that  he  frequently  found  large  quantities  of  cell- 
membranes  unchanged  in  the  feces;  also  starch-cells,  deprived  of  only  part  of 
their  contents.  The  green  coloring  principle,  chlorophyll,  was  usually  un- 
changed. The  walls  of  the  sap-vessels  and  spiral  vessels  were  quite  unaltered 
by  the  digestive  fluid,  and  were  usually  found  in  large  quantities  in  the  feces; 
their  contents,  probably,  were  removed."3 — Besides  the  undigested  residue  of 
the  food,  the  microscope  enables  us  to  recognize  the  brown  coloring  matter  of 
the  bile,  epithelium-cells  and  mucus-corpuscles,  and  various  saline  particles, 
especially  those  of  the  ammoniaco-magnesian  phosphate,5  whose  crystals  are 
well  defined ;  most  of  which  are  derived  from  the  secretions.  The  quantity  of 
fecal  discharge  which  is  daily  passed  by  an  adult,  seems  to  average  from  4  to 
6  oz.;  but  this  contains  75  per  cent,  of  water;  so  that  the  dry  solid  matter  thus 
evacuated  is  not  above  1  oz.  or  1?  oz. — The  following  is  the  result  of  the  proxi- 
mate analysis  of  the  feces  of  an  individual  in  good  health,  who  had  taken  the 
ordinary  diet  of  this  country;  as  given  by  Dr.  Percy.4 

Substances  soluble  in  ether  (brownish-yellow  fat)        .         .         .         .  11.95 

"             "            alcohol  of  .830 10.74 

"              "            water  (brown  resinoid  matter)  .         .         .         .  11.61 

Organic  matter  insoluble  in  the  above  menstrua           .         .     .,..-,  49.33 

Salts  soluble  in  water 4.76 

Salts  insoluble  in  water .         .         .  11.61 

Ultimate  analysis  of  the  same  feces  gave  the  following  as  the  proportion  of  the 
components  of  the  Organic  constituents:  Carbon 46.20,  Hydrogen  6.72,  Nitrogen 

1  It  has  been  pointed  out  to  the  Author  by  his  friend,  Mr.  Quekett,  that  elastic  fibres 
are  occasionally  to  be  met  with  in  the  Human  feces,  which  present  an  appearance  (proba- 
bly resulting  from  incipient  decomposition)  closely  resembling  that  which  is  normal  in  the 
ligamentum  nuchse  of  the  Giraffe  ($  221,  note}.     So  distinct,  indeed,  does  the  transverse 
division  then  become,  that  these  fibres,  when  peculiarly  abundant  (as  they  are  in  the  feces 
of  persons  who  have  for  some  time  been  living  upon  mutton  chops,  and  have  not  put  aside 
the  segment  of  the  aorta  which  each  chop  includes),  have  actually  been  mistaken  for  a 
Confervoid  growth  in  the  feces. 

2  The  above  passage  is  quoted  from  Messrs.  Kirkes  andPaget's  "Hand-book  of  Physio- 
logy*" in  which  it  is  derived  from  the  Memoir  by  Dr.  Rawitz,   "Ueber  die  Einfachen 
Nahrungsmittel,"  Breslau,  1846. 

3  The  presence  of  this  salt  in  the  feces  was  maintained  by  Schonlein  to  be  pathogno- 
monic  of  typhus ;  but  more  recent  and  correct  observations  have  shown  that  this  view  is 
fallacious.     Crystals  of  this  salt  sometimes  occur  in  perfectly  normal  feces;  and  in  those 
cases  in  which  the  secreted  fluids  and  the  contents  of  the  intestine  readily  undergo  de- 
composition, as  in  typhus,  cholera,  and  certain  forms  of  dysentery,  they  are  found  in 
large  numbers,  and  of  considerable  size. 

«  Simon's  "Animal  Chemistry"  (translated  by  Dr.  Day),  p.  578,  Am.  Ed. 


INTESTINAL   DIGESTION.  437 

and  Oxygen  30.71,  Ash  13.37. — The  mineral  ash  of  fecal  matter  has  been 
examined  by  Enderlin  j1  who  has  given  the  following  as  the  proportion  of  its 
ingredients. 

Chloride  of  sodium  and  alkaline  sulphates     .         .         1>367  \Soluble  in  water. 

Bibasic  phosphate  of  soda 2.633  / 

Phosphates  of  lime  and  magnesia  ....  80.3721 

Phosphate  of  iron 2.090  I  Ingoluble  in  water 

Sulphate  of  lime 4.530  [ 

Silica 7.940  J 

From  the  later  inquiries  of  Lehmann  and  others,  however,  it  appears  that  the 
proportion  of  salts  often  considerably  exceeds  that  given  by  Dr.  Percy,  ordinarily 
rising  to  23  per  cent.,  and  even  to  30£  or  31£  per  cent.,  when  an  abundant  meat 
diet  has  been  consumed.  The  potash  generally  predominates  greatly  over  the 
soda,  but  especially  when  the  diet  has  chiefly  consisted  of  muscular  flesh. — Of  the 
degree  in  which  the  bile,  as  a  whole,  enters  into  the  composition  of  the  feces,  it 
is  difficult  to  speak  with  precision.  Its  coloring  and  its  fatty  matter  are  un- 
doubtedly present ;  but  scarcely  any  traces  of  choleic  acid,  or  of  either  of  its 
conjugated  compounds,  or  of  their  soda-base,  can  be  detected ;  so  that  the  proper 
biliary  matter  must  either  have  undergone  decomposition,  so  as  to  be  no  longer 
recognizable,  or  else  it  must  have  been  reabsorbed.  The  latter  is  the  idea  now 
usually  entertained,  although  Valentin  has  endeavored  to  show  that  the  proper 
fecal  matter  is  chiefly  derived  from  decomposed  constituents  of  the  bile;  a  more 
probable  source  for  this,  however,  will  be  presently  offered.  The  indications  of 
the  presence  of  bile  are  more  distinct,  when  the  feces  have  remained  for  only  a 
short  time  in  the  large  intestine,  and  when  there  has  consequently  been  less  time 
for  its  reabsorption.  In  the  fecal  discharges  which  result  from  the  action  of 
mercurials,  large  quantities  of  biliary  matter  may  be  detected,  very  little 
changed. 

458.  Although  it  cannot  be  stated  with  certainty  what  is  the  precise  portion 
of  the  Glandular  apparatus  connected  with  the  intestinal  canal,  which  is  concerned 
in  the  elimination  of  that  peculiarly  putrescent  matter  which  gives  to  the  feces 
their  characteristic  odor,  yet  it  may  be  stated  almost  with  certainty  that  this 
matter  is  not  derived  from  the  decomposition  of  the  undigested  residue  of  the 
food.  For,  in  the  first  place,  this  residue  consists  of  matters  whose  very  inapti- 
tude for  undergoing  chemical  change  is  the  source  of  their  indigestibility ;  and 
it  is  scarcely  possible,  therefore,  to  imagine  that  in  so  short  a  period  they  should 
acquire  a  character  so  peculiarly  offensive.  But  further,  we  observe  that  fecal 
matter  is  still  discharged,  even  in  considerable  quantities,  long  after  the  intestinal 
tube  has  been  completely  emptied  of  its  alimentary  contents.  We  see  this  in 
the  course  of  many  diseases,  when  food  is  not  taken  for  several  days,  during 
which  time  the  bowels  have  been  completely  emptied  of  their  previous  contents 
by  repeated  evacuations  ;  and  whatever  then  passes,  in  addition  to  the  biliary  and 
pancreatic  fluids,  must  be  derived  from  the  intestinal  walls  themselves.  Some- 
times a  copious  flux  of  putrescent  matter  continues  to  take  place  spontaneously; 
whilst  it  is  often  produced  by  the  agency  of  purgative  medicine.  The  "colliqua- 
tive  diarrhoea/'  which  frequently  comes  on  at  the  close  of  exhausting  diseases, 
and  which  usually  precedes  death  by  starvation,  appears  to  depend,  not  so  much 
upon  a  disordered  state  of  the  intestinal  glandulse  themselves,  as  upon  the  general 
disintegration  of  the  solids  of  the  body,  which  calls  them  into  extraordinary 
activity,  for  the  purpose  of  separating  the  decomposing  matter  which  has  accu- 
mulated in  it  to  a  most  unusual  amount  (§  418).  These  views  (which  have 
long  been  taught  by  the  author)  derive  a  remarkable  confirmation  from  the  ex- 
periments of  Prof.  Liebig  on  the  production  of  artificial  fecal  matter.  For  he 

1  "Ann.  der  Chem.  und  Pharrn.,"  1844. 


438  OF  ABSORPTION   AND    SANGUIFICATION. 

has  ascertained  that  if  albuminous  or  gelatinous  compounds  be  heated  with  solid 
hydrate  of  potash,  and  the  heat  be  continued  until  the  greater  part  or  the  whole 
of  the  nitrogen  has  been  dissipated  as  ammonia,  and  hydrogen  begins  to  be  given 
off,  the  residue,  when  supersaturated  with  dilute  sulphuric  acid,  and  distilled, 
yields  a  liquid  containing  acetic  and  butyric  acids,  and  possessing  in  a  very 
intense  degree  the  peculiar  and  characteristic  odor  of  human  feces.  The  odor 
varies  according  to  the  substance  employed;  and  in  this  way  all  varieties  of  fecal 
smell  may  be  obtained.  As  the  action  of  caustic  potash  at  a  high  temperature 
is  simply  a  limited  or  incomplete  oxidation  or  combustion,  this  curious  result  con- 
firms the  view  which  had  been  previously  put  forth  by  Prof.  Liebig,  that  the 
proper  fecal  matter  is  the  product  of  the  imperfect  oxidation  which  a  portion  of 
the  histogenetic  constituents  of  the  food  undergo  in  the  course  of  their  regressive 
metamorphosis,  being  comparable  to  the  soot  or  lamp-black  of  a  furnace  or  lamp. 
It  is  further  urged  by  him,  that  the  condition  of  the  feces  differs  in  many  particu- 
lars from  that  of  substances  in  a  state  of  fermentation  or  putrefaction ;  that  their 
peculiar  odor  is  entirely  unlike  any  that  is  generated  by  the  ordinary  decompo- 
sition of  organic  compounds,  whether  azotized  or  non-azotized ;  and  that,  by 
contact  with  air,  they  themselves  undergo  a  sort  of  fermentation  or  putrefaction, 
in  which  their  peculiar  fetor  disappears — a  fact,  as  he  justly  remarks,  which  is 
full  of  significance.1  This  view  is  of  great  practical  importance ;  for  if  it  be  true 
that  the  intestinal  canal  receives  and  discharges  the  products  of  the  secreting 
action  of  a  glandular  apparatus,  whose  special  function  is  the  elimination  of 
certain  products  of  decomposition  from  the  blood,  the  facility  with  which  we 
can  stimulate  this  to  increased  action  by  certain  kinds  of  purgative  medicine, 
gives  us  a  most  valuable  means  of  augmenting  its  depurative  action.  Seeing, 
as  no  observant  Medical  Practitioner  can  avoid  doing,  how  frequently  Nature 
herself  employs  this  means  of  eliminating  morbific  matter  from  the  system — 
as  shown  by  the  immense  relief  often  given  by  an  attack  of  diarrhoaa — we  may 
look  upon  this  apparatus  as  one  which,  like  the  Liver,  the  Kidney,  or  the  Skin, 
may  frequently  with  propriety  be  stimulated  by  medicines  that  have  a  special 
action  upon  it,  and  one  through  which  some  morbific  matters  may  be  got  rid  of 
more  certainly  and  more  speedily  than  through  any  other  channel. — It  is  not 
intended  by  these  observations  to  encourage  the  system  of  violent  and  indiscri- 
minate purgation ;  but  to  show  that  purgatives,  judiciously  administered,  often 
constitute  our  best  means  of  eliminating  injurious  matters  from  the  system. 


CHAPTER  VIII. 

OF   ABSORPTION   AND    SANGUIFICATION. 

1.    Of  Absorption  from  the  Digestive  Cavity. 

459.  So  long  as  the  Alimentary  matter  remains  in  the  digestive  cavity,  how- 
ever perfect  may  be  its  state  of  preparation,  it  is  as  far  from  being  conducive  to 
the  nutrition  of  the  system,  as  if  it  were  in  contact  with  the  external  surface. 
It  is  only  when  absorbed  into  the  vessels,  and  carried  by  the  circulating  current 
through  the  very  substance  of  the  body,  that  it  becomes  capable  of  being  appro- 
priated by  its  various  tissues  and  organs.  Among  the  higher  Invertebrata,  we 
find  the  reception  of  alimentary  matter  into  the  circulating  system  to  be  entirely 

1  See  Prof.  Liebig's  "Animal  Chemistry,"  3d  edit.,  pp.  148-154. 


ABSORPTION   FROM   THE   DIGESTIVE   CAVITY. 


439 


accomplished  through  the  medium  of  the  Bloodvessels,  which  are  distributed 
upon  the  walls  of  the  digestive  cavity.  But  in  the  Vertebrata,  we  find  an 
additional  set  of  vessels  interposed  between  the  walls  of  the  intestine  and  the 
sanguiferous  system ;  for  the  purpose,  as  it  would  seem,  of  taking  up  certain 
components  of  the  nutritive  matter,  of  which  part  at  least  are  not  in  a  state  of 
perfect  solution,  and  of  preparing  them  for  being  introduced  into  the  current 
of  the  blood.  These  are  the  Absorbents  of  the  intestinal  walls ;  of  which  those 
that  are  found,  after  the  performance  of  the  digestive  process,  to  contain  the 
white  opalescent  fluid  known  as  "chyle,"  are  distinguished  as  lacteals ;  while 
the  remainder,  like  the  absorbents  of  the  system  generally,  are  known  as  lymph- 
atics. The  distinction  is  a  purely  artificial  one ;  for  the  "  lacteals"  are  the 
"lymphatics"  of  those  parts  of  the  intestinal  walls  which  they  supply,  as  is 
shown  by  the  fact  that,  during  the  intervals  of  the  digestive  process,  they  con- 
tain a  transparent  fluid  in  all  respects  similar  to  the  "lymph"  of  other  parts. 
The  Absorbents  form  a  minute  plexus  beneath  the  mucous  lining  of  the  ali- 
mentary canal  along  its  whole  extent;  but  in  the  small  intestine  they  enter  the 
villi,  at  the  extremities  of  which,  indeed,  they  may  be  said  to  commence. 
Those  only  are  entitled  to  the  designation  of  "  lacteals"  which  originate  from 
the  intestinal  canal  below  the  point  at  which  the  biliary  and  pancreatic  ducts 
pour  their  contents  into  it ;  for  above  that  point,  the  fatty  constituents  of  the 
alimentary  matter  are  not  in  a  state  of  sufficiently  fine  division  to  enter  them  ; 
and  the  absorbed  fluid  is  consequently  pellucid,  instead  of  possessing  the  milky 
aspect.  Thus,  then,  we  are  to  consider  the  lacteal  portion  of.  the  Absorbent 
system  to  be  that  part  of  it  which  is  specially  adapted,  by  its  prolongation  into 
the  villi,  for  the  reception  of  an  oleaginous  fluid ;  which  we  shall  presently  see 
to  be  taken  up  from  the  contents  of  the  alimentary  canal,  and  to  be  prepared 
for  entrance  into  the  absorbents,  by  a  set  of  peculiar  cells  developed  at  the 
radical  extremities  of  those  organs  (§  461). 

460.  The  general  structure  of  the  Villi  of  the  Intestinal  mucous  membrane 
has  been  already  described  (§§  228,  234) ;  but  the 
peculiar  disposition  of  their  component  structures 
must  here  be  more  minutely  noticed. — Each  villus 
appears  ordinarily  to  contain  but  a  single  lacteal  tube 
which  occupies  its  centre ;  in  the  larger  villi,  however, 
two  or  even  more  trunks  are  sometimes  discernible 
(Fig.  134,  A).  The  mode  in  which  this  tube  com- 
mences, near  the  extremity  of  the  villus,  has  not  yet 
been  precisely  made  out ;  but  it  seems  probable  that 
it  originates  in  a  plexus,  formed  by  the  anastomosis 
of  branches  into  which  it  subdivides.  This  much, 
however,  is  quite  certain,  that  the  lacteals  do  not  com- 
mence by  open  orifices  on  the  internal  surface  of  the 
intestinal  tube,  as  they  were  formerly  supposed  to  do. 
Each  villus  is  also  furnished  with  a  minute  plexus  of 
capillary  vessels,  which  lies  near  its  surface ;  these 
sometimes  pass  between  a  single  arterial  and  venous 
twig,  as  in  the  villus  of  the  Hare  (Fig.  133),  but  are 
sometimes  supplied  by  several  distinct  twigs,  as  in 
the  villi  of  Man  (Figs.  131,  132) ;  the  particular 
arrangement  of  the  vessels,  the  form  of  the  plexus,  &c.,  differing  considerably 
in  different  animals,  and  even  in  different  portions  of  the  intestine  of  the  same 
individual.  From  the  facts  to  be  presently  stated,  it  will  be  obvious  that  these 
bloodvessels  are  not  less  actively  concerned  in  the  absorbent  functions,  than  are 
the  lacteals  themselves;  and  there  is  evidence,  moreover,  that  the  circulation  of 


Fig.  131. 


Villi  of  the  Human  Intestine,  with 
their  capillary  plexus  injected. 


440 


OP   ABSORPTION  AND    SANGUIFICATION. 


blood  through  them  is  essential  to  the  introduction  of  chyle  into  the  absorbents.1 
Hence,  some  have  supposed  that  the  contents  of  the  lacteals  are  first  imbibed 

Fig.  132. 


A  section  of  the  Ileum,  inverted  so  as  to  show  the  ap- 
pearance and  arrangement  of  the  villi  on  an  extended 
surface,  as  well  as  the  follicles  of  Lieberkuhn ;  the  whole 
seen  under  the  microscope.  A  close  examination  of  this 
cut  will  show  a  great  number  of  black  points  in  the  spaces 
between  the  projections  of  villi :  these  are  the  follicles 
of  LieberkUhn. 


Vessels  of  an  Intestinal  Villus  of 
a  Hare,  from  a  dry  preparation  by 
Dollinger :  a,  a,  veins  filled  with 
white  injection:  Z>,  b,  arteries  in- 
jected red. 


by  the  bloodvessels,  and  are  afterwards  eliminated  from  them  by  a  kind  of 
glandular  action  on  the  part  of  the  absorbents;  but  of  this  there  is  no  adequate 
evidence ;  and  it  seems  more  probable  that  the  constant  supply  of  blood  is  re- 
quired for  that  peculiar  cell-action,  to  which  the  selection  of  the  materials  of  the 
chyle  is  due. — The  curious  fact  has  recently  been  substantiated  by  Prof.  Kolliker,a 
that  the  villi  contain  numerous  muscular  fibre-cells  (§  305),  and  that  they  pre- 
sent themselves  in  very  different  degrees  of  contraction  and  extension.  This 
observation  confirms  the  statement  formerly  made  by  M.  Lacauchie3  as  to  the 
existence  of  contractile  tissue  in  the  villi,  which  statement  was  based  on  the 
contraction  which  he  had  observed  them  to  undergo  after  their  removal  from 
the  body ;  and  also  the  yet  more  remarkable  assertion  of  MM.  Gruby  and  Dela- 
fond,  that  rhythmical  movements  of  contraction  and  extension  in  different  direc- 
tions take  place  in  the  villi  whilst  absorption  is  going  on,4  which  have  an  im- 
portant influence  on  the  propulsion  of  the  fluids  contained  within  their  vessels. 

1  See  especially  the  experiments  of  Mr.  Fenwick  in  the  "Lancet,"  Jan.  and  Feb.,  1845. 

2  "  Mikroskopische  Anatomic,"  band  ii.  $  168. 

3  "Etudes  Hydrotomiques  et  Micrographiques,"  Paris,  1844,  p.  50. 

4  "Comptes  Rendus,"  1842,  p.  1199;  and  1843,  p.  1195. 


ABSORPTION   FROM   THE   DIGESTIVE   CAVITY. 


441 


461.  When  the  Villi  are  examined  at  such  a  period  after  a  meal  containing 
oleaginous  matters,  as  has  sufficed  for  its  partial  digestion,  their  lacteals  are 
seen  to  be  turgid  with  chyle  (Fig.  134,  A)  ;  and  the  extremity  of  each  lacteal 

Fig.  134. 


Fig.  135. 


Extremity  of  Intestinal  ViHus:  seen  at  A,  during  absofption,  and  showing  absorbent  cells  and  lacteal  trunks, 
distended  with  chyle;  at  B,  during  interval  of  digestion,  showing  the  supposed  peripheral  network  of  lacteals. 

appears  to  be  imbedded  in  a  collection  of  globules  presenting  an  opalescent  ap- 
pearance, which  gives  to  the  end  of  the  villus  a  somewhat  mulberry-like  form. 
It  was  supposed  by  Prof.  Goodsir,1  by  whom  this  appearance  was  first  observed, 
that  these  globules  are  cells  developed  within  the  basement-membrane,  during 
the  act  of  absorption,  from  what  he  considered  to  be  granular  germs  visible  in 
the  same  situation  during  the  intervals  of  the  process  (B);  and  that  these  cells, 
drawing  into  themselves  during  their  growth  certain 
of  the  nutritive  materials  contained  in  the  intestinal 
canal,  are  thus  the  real  agents  in  the  selection  of  the 
substances  which  are  to  be  introduced  into  the  lac- 
teals, delivering  them  to  these,  by  the  rupture  or 
deliquescence  of  their  walls,  so  soon  as  their  own 
term  of  life  is  ended.  It  was  further  held  by  Prof. 
Goodsir,  that  the  epithelium-cells  covering  the  ex- 
tremities of  the  villi  fall  off  during  the  process  of 
absorption,  so  as  to  leave  the  villi  more  free  to  im- 
bibe the  fluids  in  contact  with  their  surface ;  and 
thus  that  a  new  set  of  absorbent  cells  is  developed 
with  every  recurrence  of  the  act  of  absorption,  and 
a  new  set  of  protective  epithelium-cells  in  the  sub- 
sequent interval.  These  views,  however,  though 
correctly  indicating  the  fact  that  the  elements  of 
chyle  are  introduced  into  the  lacteals  by  the  inter- 
mediation of  cells,  have  been  shown  to  be  erroneous 
so  far  as  regards  the  nature  of  these  cells ;  which 
several  excellent  observers3  agree  in  regarding  as 
the  proper  epithelium-cells  of  the  villi — these  not 

being  thrown    Off,  as  Prof.  Goodsir   believed,  but  SO     during  absorption:  a,  marginal  layer 

completely  changing  their  aspect  in  consequence  of   of  ePithelium-«eUs:  z>,  epithelium- 

the  imbibition  of  oleaginous  flnid  (Fig.  135),  that 

they  cease  to  be  recognizable  as  such,  unless  their 

intermediate  stages  be  traced.     The  epithelium-cells  of  the  villi  may  frequently 

be  observed  (as  formerly  mentioned)  to  be  connected  at  their  free  extremities 

_  »  "Edinb.  New  Phil.  Journ.,"  July,  1842;  and  "Anatomical  and  Pathological  Observa- 
tions," pp.  5 — 10. 

2  See  MM.  Gruby  and  Delafond,  in  "Comptes  Rendus,"  5  Juin,  1843;  Kiiss,  in  "Gaz. 
Med.  de  Strasbourg,"  No.  2,  1846;  E.  H.  Weber,  in  "Miiller's  Archiv.,"  1847;  Kolliker, 
" Mikroskopische  Anatomic,"  bandii.  §  169;  and  Bennett,  in  "Edinb.  Monthly  Journal  " 
March,  1852,  p.  283. 


Extremity  of  an  Intestinal  Villus 


442  Or   ABSORPTION   AND    SANGUIFICATION. 

by  something  like  a  continuous  membrane  (Fig.  5);  and  it  was  doubtless  this 
which  was  mistaken  by  Prof.  Goodsir  for  the  proper  basement-membrane  that 
underlies  the  epithelium-cells. — It  may,  then,  be  stated  with  some  confidence, 
that  the  epithelium-cells  covering  the  extremities  of  the  villi  are  the  real  instru- 
ments in  the  selection  and  absorption  of  the  materials  of  the  chyle;  and  that, 
drawing  these  into  their  own  cell-cavities,  they  subsequently  deliver  them  up  to 
the  lacteals,  by  which  they  are  carried  towards  the  centres  of  the  circulation. 
And  further,  that  although  it  may  be  true  that  the  epithelium-cells  are  some- 
times cast  off  in  considerable  quantities,  in  certain  disordered  states  of  the 
mucous  membrane  (as  in  cholera),  yet  there  is  no  evidence  of  its  being  thus 
exuviated  in  health;  the  appearances  which  have  led  to  the  idea  that  such 
exuviation  is  a  regular  occurrence,  being  partly  dependent  upon  the  facility  with 
which  the  villi  are  denuded  of  them  by  maceration  or  manipulation. 

462.  In  regard  to  the  degree  in  whiBh  the  function  of  Nutritive  Absorption 
is  performed  by  the  Lacteals  and  by  the  Sanguiferous  system  respectively,  con- 
siderable difference  of  opinion  has  prevailed.  When  the  Absorbent  vessels  were 
first  discovered,  and  their  functional  importance  was  perceived,  it  was  imagined 
that  the  introduction  of  alimentary  fluid  into  the  vascular  system  took  place  by 
them  alone.  A  slight  knowledge  of  Comparative  Anatomy,  however,  might 
have  sufficed  to  correct  this  error;  since  no  lacteals  exist  in  the  Invertebrated 
animals,  the  function  of  Absorption  being  performed  by  their  mesenteric  blood- 
vessels only,  whence  it  is  evident  that  these  do  possess  the  power  of  absorption : 
and  it  is  scarcely  to  be  supposed  that  they  should  not  exercise  this  power  in 
Vertebrated  animals  also,  since  their  disposition  on  the  walls  of  the  intestinal 
cavity  is  obviously  favorable  to  it.  On  the  other  hand,  the  introduction  of  a 
new  and  distinct  system  of  vessels  would  seem  to  indicate,  that  they^  must  have 
some  special  purpose;  and  there  can  be  no  doubt  that  the  absorption  of  a  par- 
ticular kind  of  nutritive  matter  is  that  for  which  they  are  designed. — That 
Absorption  is  effected,  to  a  very  considerable  amount,  by  the  agency  of  the 
Bloodvessels,  is  shown  by  the  readiness  with  which  aqueous  fluids,  and  even 
alcohol,  are  taken  up  from  the  parietes  of  the  stomach,  and  are  carried  into  the 
general  circulation.  Thus  in  a  case  of  extroversion  of  the  bladder,  observed  by 
Mr.  Erichsen,1  in  which  the  urinary  secretion  could  be  collected  immediately 
on  its  passing  from  the  kidney,  when  a  solution  of  ferrocyanide  of  potassium 
was  taken  into  the  stomach,  this  salt  was  detected  in  the  urine  in  one  instance 
within  1  minute,  and  in  three  other  instances  within  2£  minutes.  In  all  these 
cases,  however,  the  stomach  may  be  presumed  to  have  been  empty,  and  the  vas- 
cular system  in  a  state  of  aptitude  for  absorption;  since  the  experiments  were 
made  either  after  a  long  fast,  or  at  least  four  hours  after  a  light  meal.  When, 
on  the  other  hand,  the  salt  was  introduced  into  the  stomach  soon  after  the  in- 
gestion  of  alimentary  substances,  a  much  longer  period  elapsed  before  it  could 
be  detected  in  the  urine;  thus,  when  a  substantial  meal  had  been  taken  two 
hours  previously,  the  interval  was  12  minutes;  when  tea  and  bread-and-butter 
had  been  taken  one  hour  previously,  the  interval  was  14  minutes ;  a  similar 
meal  having  been  taken  twenty -four  minutes  previously,  the  interval  was  16 
minutes;  when  only  two  minutes  had  passed  since  the  conclusion  of  such  a 
meal,  the  interval  was  27  minutes ;  and  when  a  solid  meal  had  been  concluded 
just  before  the  introduction  of  the  salt,  the  interval  was  39  minutes.2 — These  facts 

1  "Medical  Gazette,"  vol.  xxxvi.  p.  363. 

2  The  great  rapidity  with  which  soluble  salts,  introduced  into  the  stomach,  make  their 
appearance  in  the  urine,  has  led  M.  Cl.  Bernard  to  think  that  some  more  direct  channel 
must  exist  for  their  passage  from  the  stomach  to  the  kidneys,  than  that  which  the  ordi- 
nary current  of  the  sanguiferous  circulation  affords.     And  he  has  advanced  the  extraordi- 
nary doctrine,  that  whilst  absorption  is  going  on,  there  is  a  constriction  of  the  vena  cava 
above  the  entrance  of  the  hepatic  vein,  whereby  a  reflux  of  the  blood  discharged  by  it 


ABSORPTION   FROM   THE   DIGESTIVE   CAVITY.  443 

are  of  great  importance,  in  showing  the  very  marked  influence  which  the  state 
of  the  stomach  exercises  upon  the  absorption  of  matters  introduced  into  it.  Not 
less  important,  however,  is  the  state  of  the  vascular  system  in  regard  to  turges- 
cence  or  emptiness;  for  it  was  found  by  Magendie,  that  when  he  had  injected 
a  considerable  quantity  of  water  into  the  veins  of  a  dog,  poison  was  absorbed 
very  slowly;  whilst,  if  he  relieved  the  distension  by  bleeding,  there  was  speedy 
evidence  of  its  entrance  into  the  circulation. — The  rapidity  with  which  not  only 
aqueous  but  alcoholic  liquids  introduced  into  the  stomach  may  pass  into  the 
general  circulation,  has  been  shown  by  the  experiments  of  Dr.  Percy;1  who 
found  that  when  strong  alcohol  was  injected  into  the  stomach  of  dogs,  the  ani- 
mals would  sometimes  fall  insensible  to  the  ground  immediately  upon  the  com- 
pletion of  the  injection,  their  respiratory  and  cardiac  movements  ceasing  within 
two  minutes;  and  that  on  post-mortem  examination  in  such  cases,  the  stomach 
was  nearly  empty,  whilst  the  blood  was  highly  charged  with  alcohol ;  thus  ren- 
dering it  highly  probable,  that  not  merely  the  final  destruction  of  nervous  power, 
but  the  immediate  loss  of  sensibility,  was  due  to  the  action  of  alcoholized  blood 
upon  the  nervous  centres. — Finally,  numerous  experiments  have  been  made  by 
various  physiologists,  which  have  demonstrated  the  absorption  of  alimentary  and 
other  substances  from  the  walls  of  the  Stomach;  these  substances  having  been 
prevented  from  passing  into  the  intestine,  by  a  ligature  around  the  pylorus. 
Now,  as  the  Absorbent  system  does  not  present  that  peculiar  arrangement  in 
the  coats  of  the  stomach,  which  it  does  in  those  of  the  intestinal  tube,  there 
can  be  little  doubt  that  the  introduction  of  such  substances  into  the  system 
must  be  effected  chiefly,  if  not  entirely,  through  the  medium  of  its  capillary 
Bloodvessels. 

463.  That  the  Bloodvessels  of  the  Intestinal  tube,  also,  largely  participate  in 
the  introduction  of  soluble  alimentary  matter  into  the  system,  has  been  clearly 
proved  by  various  observations  upon  the  constitution  of  the  blood  of  the  mesen- 
teric  veins  (§  167) ;  these  having  shown,  that  after  the  digestion  of  albuminous 
and  farinaceous  or  saccharine  substances,  albuminose,  dextrin,  grape-sugar,  and 
lactic  acid  are  detectible  in  that  fluid,  whose  usual  composition  is  greatly  altered 
by  the  presence  of  these  substances,  as  well  as  by  the  augmented  proportion  of 
water  which  it  contains.  We  may  consider  the  Sanguiferous  vessels,  then,  as 
affording  the  usual  channel  by  which  a  large  part  of  the  nutritive  materials  are 
introduced  into  the  system ;  but  these  are  not  allowed  to  pass  into  the  general 
current  of  the  circulation,  until  they  have  been  subjected  to  an  important  assimi- 
lating process,  which  it  appears  to  be  one  great  office  of  the  Liver  to  perform, 
whereby  they  are  rendered  more  fit  for  the  purposes  they  are  destined  to  serve 
in  the  economy.  Of  this  we  shall  presently  have  to  speak  (§  472). — But  the 

takes  place,  so  that  it  passes  into  the  renal  vein,  without  reaching  the  heart.  And  he 
asserts  that  a  peculiar  thickening  of  the  muscular  coat  exists  in  the  upper  part  of  the 
vena  cava,  whereby  its  contraction  is  occasioned;  also  that  there  are  (in  the  horse  at  least) 
direct  passages  by  which  a  part  of  the  portal  blood  may  be  discharged  into  the  vena  cava, 
without  passing  through  the  liver.  ("L'Union  Medicale,"  1849,  No.  115.)  Now,  in  the 
first  place,  this  hypothesis  is  not  necessary  to  explain  the  facts ;  for,  as  will  be  shown 
hereafter  ($  509),  there  is  evidence  of  the  transmission  of  substances  to  other  parts,  with 
at  least  as  much  rapidity  as  is  indicated  by  their  appearance  in  the  urine.  And,  in  the 
second  place,  if  the  supposed  reflux  really  took  place,  it  must  affect  the  whole  venous  cir- 
culation of  the  trunk  and  lower  extremities,  except  such  as  the  vena  azygos  and  a  few 
other  small  channels  could  provide  for ;  and  must  occasion  (to  make  good  the  conditions 
of  the  problem)  not  merely  a  stagnation,  but  an  absolute  reflux,  so  that  the  veins  are  meta- 
morphosed into  arteries,  and  the  arteries  into  veins.  How  the  vis  d  tergo,  originally  de- 
rived from  the  heart,  can  thus  be  strong  enough  at  the  very  end  of  the  systemic  circulation, 
not  merely  to  neutralize,  but  actually  to  overcome,  the  force  which  it  exercises  almost 
close  to  the  heart,  M.  Bernard  has  not  informed  us. 

1  "Experimental  Inquiry  concerning  the  Presence  of  Alcohol  in  the  Ventricles  of  the 
Brain,"  p.  61.  *"«»" " 


444  Or  ABSORPTION   AND    SANGUIFICATION. 

absorbent  power  which  the  bloodvessels  of  the  Alimentary  canal  possess,  is  not 
limited  to  alimentary  substances;  for  it  is  through  them,  almost  exclusively, 
that  soluble  matters  of  every  other  description  are  received  into  the  circulation. 
This,  which  may  now  be  considered  a  well-established  fact,  was  first  clearly 
shown  by  the  carefully-conducted  experiments  of  MM.  Tiedemann  and  Gmelin,1 
who  mingled  with  the  food  of  animals  various  substances,  which,  by  their  color, 
odor,  or  chemical  properties,  might  be  easily  detected  in  the  fluids  of  the  body : 
after  some  time  the  animal  was  examined;  and  the  result  was,  that  unequivocal 
traces  of  such  substances  were  not  unfrequently  detected  in  the  venous  blood 
and  in  the  urine,  whilst  it  was  only  in  a  very  few  instances  that  any  indication 
of  them  could  be  discovered  in  the  chyle.  The  coloring  matters  employed  were 
various  vegetable  substances;  suoh  as  gamboge,  madder,  and  rhubarb;  the 
odorous  substances  were  camphor,  musk,  assafetida,  &c. ;  while,  in  other  cases, 
various  saline  bodies,  such  as  chloride  of  barium,  acetate  of  lead  and  of  mercury, 
and  some  of  the  prussiates,  which  might  easily  be  detected  by  chemical  tests, 
were  mixed  with  the  food.  The  coloring  matters,  for  the  most  part,  were  carried 
out  of  the  system,  without  being  received  either  into  the  veins  or  lacteals ;  the 
odorous  substances  were  generally  detected  in  the  venous  blood  and  in  the  urine, 
but  not  in  the  chyle ;  whilst  of  the  saline  substances,  many  were  found  in  the 
blood  and  in  the  urine,  and  a  very  few  only  in  the  chyle.  A  similar  conclusion 
might  be  drawn  from  the  numerous  instances  in  which  various  substances  in- 
troduced into  the  intestines  have  been  detected  in  the  blood,  although  the 
thoracic  duct  had  been  tied;  but  these  results  are  less  satisfactory,  because 
even  if  there  be  no  direct  communication  (as  maintained  by  many)  between  the 
lacteals  and  the  veins  in  the  mesenteric  glands,  the  partitions  which  separate 
their  respective  contents  are  evidently  so  thin,  that  transudation  may  readily 
take  place  through  them. 

464.  This  Absorption  by  the  Bloodvessels  is  a  simply  physical  operation, 
depending  upon  the  relative  consistency  and  miscibility  of  the  blood  and  of  the 
liquids  to  be  absorbed,  and  upon  the  rapid  movement  of  the  blood  through  the 
vessels.  Where  the  contents  of  the  alimentary  canal  are  of  less  specific  gravity 
than  the  blood,  and  are  capable  of  readily  mingling  with  it,  an  endosmotic  cur- 
rent will  be  established,  through  the  delicate  parietes  of  the  bloodvessels  and 
their  thin  investments,  between  the  two  liquids,  the  former  passing  towards  the 
other;  and  in  this  mode,  albuminous,  gelatinous,  saccharine,  saline,  and  other 
soluble  substances  may  be  caused  to  enter  the  blood,  if  their  solution  be  not  too 
concentrated.  But  if  their  density  be  equal  to  that  of  the  blood,  or  nearly  so, 
little  or  no  absorption  is  likely  to  take  place;  and  one  purpose  which  is  answered 
by  the  very  copious  discharge  of  aqueous  fluid  into  the  alimentary  canal,  during 
the  operation  of  digestion,  is  obviously  the  reduction  of  the  density  of  the  solu- 
tion to  a  favorable  point.  If,  again,  the  density  of  the  contents  of  the  aliment- 
ary canal  should  exceed  that  of  the  blood,  an  endosmotic  current  might  perhaps 
be  established  in  the  opposite  direction ;  but  their  dilution  would  probably  be 
effected  so  speedily,  that  little  of  the  contents  of  the  bloodvessels  would  be  thus 
drawn  forth,  more  especially  as  animal  membranes  appear  to  have  a  special 
power  of  resisting  the  passage  of  Albumen,  whilst  they  give  free  transmission 
to  Albuminose.3 — That  the  movement  of  blood  in  the  vessels  will  vastly  increase 

1  "Versuche  iiber  die  Wcge  auf  welchen  Substanzen  aus  dern  Magen  und  Darmkanal 
ins  Blut  gelangen,"  Heidelberg,  1820. 

2  It  is  considered  by  Liebig  that  the  purgative  effects  of  concentrated  saline  solutions 
are  to  be  accounted  for  on  this  principle — the  establishment  of  an  endosmotic  current 
from  instead  of  towards  the  circulating  system.     It  is  difficult,  however,  thus  to  account 
for  all  the  phenomena  of  saline  purgation ;  and  the  Author  greatly  doubts  the  validity  of 
the  explanation. — It  may,  however,  be  applied,  with  more  probability,  to  the  fact  of  which 
the^  Author  was  assured  by  the  late  Dr.  Prout;  viz.,  that  having  fed  a  dog  upon  pure  starch, 


ABSORPTION   FROM   THE   BODY   IN   GENERAL.  445 

the  rate  of  endosmotic  absorption,  is  easily  proved  experimentally;  and  this  it 
is  which  constitutes  the  main  difference  between  the  living  and  the  dead  subject.1 

465.  It  is  a  very  remarkable  fact,  which  has  recently  been  fully  substantiated, 
that  not  merely  soluble  matters,  but  insoluble  substances  in  a  state  of  minute 
division,  may  find  their  way  from  the  alimentary  canal  into  the  current  of  the 
circulation.     Thus  it  was  found  by  Oesterlen3  that  particles  of  finely-divided 
charcoal,  introduced  into  the  alimentary  canal,  could  be  distinguished  in  the 
blood  of  the  mesenteric  veins ;  and  similar  results  have  been  obtained  by  Eber- 
hard,  and  by  Mensonides  and  Bonders,  not  only  with  charcoal,  but  also  with 
sulphur,  and  even  with  starch,  the  latter  substance  being  at  once  detectible  in 
the  blood  by  the  iodine-test.     It  is  doubtful  whether  these  particles  are  taken 
up  by  the  lacteal  system;  though  Bonders  seems  of  opinion,  from  finding  them 
deposited  in  the  lungs  rather  than  in  the  liver,  that  the  former  is  their  more 
usual  channel  of  entrance.3     How  they  find  their  way  through  the  walls  of  the 
vessel,  however,  is  at  present  a  complete  mystery. 

2. — Absorption  from  the  Body  in  general. 

466.  The  Mucous  Membrane  of  the  alimentary  canal  is  by  no  means  the  only 
channel  through  which  nutritive  or  other  substances  may  be  introduced  into  the 
circulating  apparatus  from  external  sources.     The  Lymphatic  system  is  present 
in  all  animals  which  have  a  lacteal  system ;  and  the  two,  as  already  pointed 
out,  evidently  constitute  one  set  of  vessels.     The  Lymphatics,  however,  instead 
of  commencing  on  the  intestinal  walls,  are  distributed  through  most  of  the  vas- 
cular tissues  of  the  body,  and  especially  in  the  Skin;  but  their  number  bears 
no  proportion  whatever  to  the  vascularity  of  the  several  tissues,  or  to  the  amount 
of  interstitial  change  which  these  undergo;  and  it  is  remarkable  that  the  Nerv- 
ous centres  should  be  (so  far  as  is  yet  known)  entirely  destitute  of  them,  and 
that  they  should  be  so  scanty  in  the  interior  of  Muscles,  as  to  suggest  that  they 
belong  rather  to  the  connective  areolar  tissue  than  to  the  muscular  substance 
itself  (§308).     Their  origins  cannot  be  clearly  traced;  but  they  seem  in  general 
to  form  a  plexus  in  the  substance  of  the  tissues,  from  which  the  convergent 
trunks  arise.     After  passing,  like  the  lacteals,  through  a  series  of  glandular 
bodies  (the  precise  nature  of  which  will  be  presently  considered,  §  473),  they 
empty  their  contents  into  the  same  receptacle  with  the  lacteals ;  and  the  mingled 
products  of  both  pass  into  the  Sanguiferous  system. — We  find  in  the  Skin,  also, 
a  most  copious  distribution  of  capillary  bloodvessels,  the  arrangement  of  which 
is  by  no  means  unlike  that  of  the  bloodvessels  of  the  alimentary  canal;  and  its 
surface  is  further  extended  by  the  elevations  that  form  the  sensory  papillae  (Fig. 
115),  which  are  in  many  points  comparable  to  the  intestinal  villi,  although  their 
special  function  is  so  different. 

467.  In  the  lowest  tribes  of  animals,  and  in  the  earliest  condition  of  the 
higher,  it  would  seem  as  if  Absorption  by  the  external  surface  is  almost  equally 
important  to  the  maintenance  of  life,  with  that  which  takes  place  through  the 
internal  reflexion  of  it  forming  the  walls  of  the  Digestive  cavity.     In  the  adult 
condition  of  most  of  the  higher  animals,  however,  the  special  function  of  the 
latter  is  so  much  exalted,  as  usually  to  supersede  the  necessity  of  any  other 

he  had  found  albumen  in  the  duodenum.  On  this  fact  Dr.  Prout  much  relied  as  a  proof 
of  the  convertibility  of  starch  into  albumen — an  idea  which  would  now  be  universally  con- 
demned by  Organic  Chemists ;  but  it  does  not  seem  difficult  to  believe,  that  the  presence 
of  a  viscid  mass  of  half-digested  starch  might  have  determined  a  transudation  of  albumen 
from  the  bloodvessels  by  endosmosis. 

1  On  the  whole  of  this  subject,  see  the  Author's  "Princ.  of  Phys.,  Gen.  and  Comp.," 
CHAP.  xi.  Am.  Ed. 

2  "Heller's  Archiv.,"  1847.  3  "Henle's  Zeitschrift,"  1851, 


446  OF   ABSORPTION   AND    SANGUIFICATION. 

supply;  and  the  function  of  the  cutaneous  and  pulmonary  surfaces  may  be 
considered  as  rather  that  of  exhalation,  than  of  absorption.1  But  there  are 
peculiar  conditions  of  the  system,  in  which  the  imbibition  of  fluid  through  these 
surfaces  is  performed  with  great  activity,  supplying  what  would  otherwise  be  a 
most  important  deficiency.  It  may  take  place  either  through  the  direct  appli- 
cation of  fluid  to  the  surface,  or  even  through  the  medium  of  the  atmosphere, 
in  which  a  greater  or  less  proportion  of  watery  vapour  is  usually  dissolved. 
This  absorption  occurs  most  vigorously,  when  the  system  has  been  drained  of 
its  fluid,  either  by  an  excess  of  the  excretions,  or  by  a  diminution  of  the  regular 
supply. 

468.  It  may  be  desirable  to  adduce  some  individual  cases,  which  will  set  this 
function  in  a  striking  point  of  view ;  and  those  may  be  first  noticed,  in  which 
the  Absorption  took  place  through  the  contact  of  liquids  with  the  skin.  It  is 
well  known  that  shipwrecked  sailors,  and  others,  who  are  suffering  from  thirst, 
owing  to  the  want  of  fresh  water,  find  it  greatly  alleviated,  or  altogether  relieved, 
by  dipping  their  clothes  into  the  sea,  and  putting  them  on  whilst  still  wet,  or 
by  frequently  immersing  their  own  bodies.3 — Dr.  Currie  relates  the  case  of  a 
patient  laboring  under  dysphagia  in  its  most  advanced  stage ;  the  introduction 
of  any  nutriment,  whether  solid  or  fluid,  into  the  stomach,  having  become  per- 
fectly impracticable.  Under  these  melancholy  circumstances,  an  attempt  was 
made  to  prolong  his  existence,  by  the  exhibition  of  nutritive  enemata,  and  by 
immersion  of  the  body,  night  and  morning,  in  a  bath  of  milk  and  water.  Dur- 
ing the  continuance  of  this  plan,  his  weight,  which  had  previously  been  rapidly 
diminishing,  remained  stationary,  although  the  quantity  of  the  excretions  was 
increased.  How  much  of  the  absorption,  which  must  have  been  effected  to 
replace  the  amount  of  excreted  fluid,  is  to  be  attributed  to  the  baths,  and  how 
much  to  the  enemata,  it  is  not  easy  to  say;  but  it  is  important  to  remark  that 
"  the  thirst,  which  was  troublesome  during  the  first  days  of  the  patient's 
abstinence,  was  abated,  and,  as  he  declared,  removed  by  the  tepid  bath,  in 
which  he  had  the  most  grateful  sensations/'  "  It  cannot  be  doubted,"  Dr. 
Currie  observes,  "  that  the  discharge  by  stool  and  perspiration  exceeded  the 
weight  of  the  clysters;"  and  the  loss  by  the  urinary  excretion,  which  increased 
from  24  oz.  to  36  oz.  under  this  system,  is  only  to  be  accounted  for  by  the 
cutaneous  absorption.3 — Dr.  S.  Smith  mentions  that  a  man,  who  had  lost  nearly 
3  Ibs.  by  perspiration,  during  an  hour  and  a  quarter's  labor  in  a  very  hot  atmo- 
sphere, regained  8  oz.  by  immersion  in  a  warm  bath  at  95°,  for  half  an  hour.4 
— The  experiments  of  Dr.  Madden5  on  his  own  person  show  that  a  positive 
increase  usually  takes  place  in  the  weight  of  the  body,  during  immersion  in  the 
warm  bath,  even  though  there  is  at  the  same  time  a  continual  loss  of  weight  by 
pulmonary  exhalation,  and  by  transudation  from  the  skin.6  This  increase  was, 

'  We  have  a  remarkable  exception  to  this  general  statement,  however,  in  the  case  of 
Frogs  and  other  Batrachia,  which  are  characterized  by  the  softness  of  their  skins  and  the 
thinness  of  their  epidermic  covering ;  for  cutaneous  absorption  seems  in  them  to  be  no  less 
active  than  their  cutaneous  exhalation  and  respiration  are  well  known  to  be.  Thus  Frogs, 
which  habitually  live  in  a  moist  atmosphere,  seldom  or  never  drink ;  yet  when  they  have 
lost  fluid  by  exposure  to  hot  dry  air,  they  will  regain  their  weight  by  being  left  for  a  time 
upon  moist  sand ;  and  the  bladder,  which  serves  as  a  reservoir  of  water  for  cutaneous 
exhalation,  though  previously  emptied,  will  be  refilled. 

2  See  a  collection  of  such  cases  in  Dr.  Madden's  "  Experimental  Inquiry  into  the  Phy- 
siology of  Cutaneous  Absorption,"  p.  47. 

3  "Medical  Reports,"  vol.  i.  pp.  308—326.     4  "Philosophy  of  Health,"  vol.  ii.  p.  396. 

5  Op.  cit.,  pp.  59—63. 

6  That  part  of  the  function  of  cutaneous  transpiration,  which  consists  in  simple  exhala- 
tion, is  of  course  completely  checked  by  such  immersion ;  but  that  which  is  the  result  of 
an  actual  secreting  process  in  the  cutaneous  glands  (CHAP.  xii.  SECT.  4)  is  increased  by 
heat,  even  though  this  be  accompanied  with  moisture. 


ABSORPTION   FROM   THE   BODY   IN   GENERAL.  447 

in  some  instances,  as  much  as  5  drachms  in  half  an  hour;  whilst  the  loss  of 
weight  during  the  previous  half  hour  had  been  6£  drachms:  so  that,  if  the  same 
rate  of  loss  were  continued  in  the  bath,  the  real  gain  by  absorption  must  have 
been  nearly  an  ounce  and  a  half.  Why  this  gain  was  much  less  than  in  the 
cases  just  alluded  to,  is  at  once  accounted  for  by  the  fact,  that  there  was  no 
deficiency,  in  the  latter  case,  of  the  fluids  naturally  present  in  the  body. 

469.  There  are  certain  phenomena,  which,  if  accurately  recorded,  cannot  be 
accounted  for  in  any  other  way  than  by  admitting  that,  under  particular  cir- 
cumstances, a  considerable  amount  of  water  may  be  absorbed  from  the  vapor 
of  the  atmosphere.     The  following  are  among  the  most  satisfactory  and  circum- 
stantial observations  that  have  been  adduced  in  support  of  this  position.     Lining 
observed  that  his  body  on  one  occasion  increased  in  weight  during  two  hours  to 
the  amount  of  8£  oz.,  allowance  being  made  for  the  amount  of  fluid  ingested 
during  that  time,  and  for  the  quantity  passed  off  by  the  urine  and  by  cutaneous 
transpiration.1     Dr.  Jurin  affirms  that  he  ascertained  an  increase  of  18  oz.  to 
have  taken  place  during  a  night  passed  in  a  cool  room  after  a  day's  exercise 
and  abstinence.3     It  is  stated  by  Dr.  Watson,3  that  a  lad  at  Newmarket,  having 
been  almost  starved,  in  order  that  he  might  be  reduced  to  a  proper  weight  for 
riding  a  match,  was  weighed  at  9  A.  M.,  and  again  at  10  A.  M.;  and  he  was 
found  to  have  gained  nearly  30  oz.  in  weight  in  the  course  of  this  hour,  though 
he  had  only  drunk  half  a  glass  of  wine  in  the  interim.     A  parallel  instance  was 
related  to  the  Author  by  the  late  Sir  Gr.  Hill,  then  Governor  of  St.  Vincent :  a 
jockey  had  been  for  some  time  in  training  for  a  race,  in  which  that  gentleman 
was  much  interested,  and  had  been  reduced  to  the  proper  weight;  on  the  morn- 
ing of  the  trial,  being  much  oppressed  with  thirst,  he  took  one  cup  of  tea;  and 
shortly  afterwards  his  weight  was  found  to  have  increased  .6  Ibs.,  so  that  he  was 
incapacitated  for  riding. — Nearly  the  whole  of  the  increase  in  the  former  case, 
and  at  least  three-fourths  of  it  in  the  latter,  must  be  attributed  to  absorption  from 
the  vapor  of  the  atmosphere ;  probably,  however,  rather  through  the  lungs  than 
through  the  skin.     If  the  possibility  of  such  absorption  be  admitted,  we  are 
probably  to  attribute  to  it  the  chief  part  of  the  excess  of  watery  fluid  which 
cannot  be  otherwise  accounted  for,  in  the  following  instances. — Dr.  Dill4  relates 
the  case  of  a  diabetic  patient,  who  for  five  weeks  passed  24  Ibs.  of  urine  every 
twenty-four  hours;  his  ingesta  during  the  same  period  amounted  to  22  Ibs.     At 
the  commencement  of  the  disease  he  weighed  145  Ibs.;  and  when  he  died,  27 
Ibs.  of  loss  had  been  sustained.     The  daily  excess  of  the  excretions  over  the 
fluid  ingesta  could  not  have  been  less  than  4  Ibs.;  making  140  Ibs.  for  the 
thirty-five  days  during  which  the  complaint  lasted.     If  from  this  we  deduct  the 
amount  of  diminution  which  the  weight  of  the  body  sustained  during  the  time, 
we  shall  still  have  113  Ibs.  to  be  accounted  for,  which  can  only  have  entered 
the  body  from  the  atmosphere. — A  case  of  ovarian  dropsy  has  been  recorded  by 
Mr.  Ford,5  in  which  it  was  observed  that  the  patient,  during  eighteen  days, 
drank  692  oz.  or  43  pints  of  fluid,  and  that  she  discharged  by  urine  and  by 
paracentesis  1298  oz.  or  91  pints,  which  leaves  a  balance  of  606  oz.  or  38  pints, 
to  be  similarly  accounted  for.6 

470.  Not  only  water,  but  substances  dissolved  in  it,  may  be  thus  introduced. 

1  "  Philosophical  Transactions,"  1743,  p.  496. 

2  Klapp,  "Inaug.  Dissert."  p.  30,  cited  by  Dr.  Madden. 

3  "Chemical  Essays,"  vol.  iii.  p.  100. 

4  "Trans,  of  Med.-Chirurg.  Soc.  of  Edinb.,"  vol.  ii. 

5  "Medical Communications,"  vol.  ii.  p.  130. 

6  In  this  case,  however,  as  in  others  of  a  similar  kind,  something  is  to  be  allowed  for 
the  quantity  of  water  contained  in  the  solid  food  ingested ;  but  this  may  be  fairly  considered 
not  to  exceed  the  quantity  lost  by  pulmonary  and  cutaneous  exhalation,  and  discharged  in 
the  fecal  evacuations. 


448  OF   ABSORPTION   AND    SANGUIFICATION. 

It  has  been  found  that,  after  bathing  in  infusions  of  madder,  rhubarb,  and 
turmeric,  the  urine  was  tinged  with  these  substances ;  and  that  a  garlic  plaster 
affected  the  breath,  when  every  care  was  taken,  by  breathing  through  a  tube 
connected  with  the  exterior  of  the  apartment,  that  the  odor  should  not  be  re- 
ceived into  the  lungs.1  Gallic  acid  has  been  found  in  the  urine,  after  the  external 
application  of  a  decoction  of  a  bark  containing  it;  and  the  soothing  influ- 
ence, in  cases  of  neuralgic  pain,  of  the  external  application  of  cherry-laurel 
water,  is  well  known.  Many  saline  substances  are  absorbed  by  the  skin, 
when  applied  to  it  in  solution ;  and  it  is  interesting  to  remark  that,  contrary 
to  what  happens  in  regard  to  the  absorption  of  these  from  the  alimentary  canal, 
they  are  for  the  most  part  more  readily  discoverable  in  the  Absorbents  than  in 
the  Veins.  This  is  probably  due  to  the  fact  that  the  imbibition  of  them  takes 
place  entirely  according  to  physical  laws;  in  conformity  with  which  they  pass 
most  readily  into  the  vessels  which  present  the  thinnest  walls  and  the  largest 
surface.  In  the  intestines,  the  vascular  plexus  on  each  villus  is  far  more  exten- 
sive than  the  ramifying  lacteal  which  originates  in  it ;  and  as  the  walls  of  the 
veins  are  thin,  there  is  considerable  facility  for  the  entrance  of  saline  and  other 
substances  into  the  general  current  of  the  circulation :  but  in  the  skin,  the  lymph- 
atics are  distributed  much  more  minutely  and  extensively  than  the  veins;  and 
soluble  matters,  therefore,  enter  them  in  preference  to  the  veins.  The  absorbent 
power  of  the  lymphatics  of  the  skin  is  well  shown  by  the  following  experiments. 
A  bandage  having  been  tied  by  Schreger  round  the  hind-leg  of  a  puppy,  the  limb 
was  kept  for  twenty-four  hours  in  tepid  milk ;  at  the  expiration  of  this  period, 
the  lymphatics  were  found  full  of  milk,  whilst  the  veins  contained  none.  In 
repeating  this  experiment  upon  a  young  man,  no  milk  could  be  detected  in  the 
blood  drawn  from  a  vein.  It  has  been  shown  by  Miiller  that,  when  the  posterior 
extremities  of  a  frog  were  kept  for  two  hours  in  a  solution  of  prussiate  of  potass, 
the  salt  had  freely  penetrated  the  lymphatics,  but  had  not  entered  the  veins. — 
It  does  not  follow,  however,  from  these  and  similar  experiments,  that  in  all 
tissues  the  lymphatics  absorb  more  readily  than  the  veins ;  for  as  the  capillary 
bloodvessels  in  the  lungs  are  much  more  freely  exposed  to  the  surface  of  the 
air-cells  than  are  the  lymphatics,  we  should,  on  the  principles  just  now  stated, 
expect  the  former  to  absorb  more  readily.  This  appears  from  experiment  to  be 
the  fact;  for,  when  a  solution  of  prussiate  of  potass  was  injected  by  Mayer  into 
the  lungs,  the  salt  could  be  detected  in  the  serum  of  the  blood  much  sooner  than 
in  the  lymph,  and  in  the  blood  of  the  left  cavities  of  the  heart,  before  it  had 
reached  that  of  the  right. 

471.  Our  inferences  with  regard  to  the  ordinary  functions  of  the  Lymphatic 
system,  however,  must  be  rather  drawn  from  the  nature  of  the  fluid  which  it 
contains,  and  from  the  uses  subsequently  made  of  it,  than  from  such  experi- 
ments as  the  preceding.  We  shall  presently  see,  that  there  is  a  close  corre- 
spondence in  composition  between  the  Chyle  of  the  Lacteals,  and  the  Lymph  of 
the  Lymphatics;  the  chief  difference  being  the  presence  of  a  considerable  quantity 
of  fatty  matter  in  the  former,  and  of  a  larger  proportion  of  the  assimilable  sub- 
stances (albumen  and  fibrin)  which  are  equally  characteristic  of  both  (§  474). 
This  evident  conformity  in  the  nature  of  the  fluid  which  these  two  sets  of  vessels 
transmit,  joined  to  the  fact  that  the  fluid  Lymph,  like  the  Chyle,  is  conveyed 
into  the  general  current  of  the  circulation,  just  before  the  blood  is  again  trans- 
mitted to  the  system  at  large,  almost  inevitably  leads  to  the  inference,  that  the 
lymph  is,  like  the  chyle,  a  nutritious  fluid,  and  is  not  of  an  excrementitious 
character,  as  maintained  by  Hunter  and  his  followers.3  On  the  other  hand,  the 

1  Prof.  Dunglison's  «  Human  Physiology,"  7th  edit.  vol.  i.  p.  688. 

2  Since  the  time  of  Hunter,  who  first  brought  prominently  forwards  the  doctrine  alluded 
to,  it  has  been  commonly  supposed  (in  this  country  at  least)  that  the  function  of  the  Lymph- 


ELABORATION   OF   NUTRIENT    MATERIALS.  —  SANGUIFICATION.      449 

close  resemblance  between  the  contents  of  the  Lymphatics,  and  diluted  Liquor 
Sanguinis,  seems  to  indicate  that  the  former  are  partly  derived  from  the  fluid 
portion  of  the  blood,  which  has  transuded  through  the  walls  of  the  capillary 
vessels ;  and  we  shall  presently  see  reason  to  believe,  that  this  transudation  is 
partly  for  the  purpose  of  subjecting  the  crude  materials,  which  may  have  been 
taken  up  direct  into  the  bloodvessels,  to  an  elaborating  or  preparatory  agency, 
such  as  it  seems  to  be  the  especial  object  of  the  Lacteal  system  to  exert  upon 
the  nutritive  substances  which  it  serves  to  introduce  into  the  circulation. — But 
it  seems  not  impossible  that  there  may  be  another  source  for  the  contents  of  the 
Lymphatics.  We  have  already  had  to  allude,  on  several  occasions,  to  the  dis- 
integration which  is  continually  taking  place  within  the  living  body;  whether  as 
a  result  of  the  limited  duration  of  the  life  of  its  component  parts,  or  as  a  con- 
sequence of  the  decomposing  action  of  Oxygen.  Now  the  death  of  the  tissues 
by  no  means  involves  their  immediate  and  complete  destruction;  and  there  seems 
no  more  reason,  why  an  animal  should  not  derive  support  from  its  own  dead 
part,  than  from  the  dead  body  of  another  individual.  Whilst,  therefore,  the 
matter,  which  has  undergone  too  complete  a  disintegration  to  be  again  employed 
as  nutrient  material,  is  carried  off  by  the  excreting  processes,  that  portion  which 
is  capable  of  being  again  assimilated,  may  be  taken  up  by  the  Lymphatic  system. 
If  this  be  the  case,  we  may  say,  with  Dr.  Prout,  that  "a  sort  of  digestion  is 
carried  on  in  all  parts  of  the  body/7 — It  may  be  stated,  then,  as  a  general  pro- 
position, that  the  function  of  the  Absorbent  System  is  to  take  up,  and  to  convey 
into  the  Circulating  apparatus,  such  substances  as  are  capable  of  appropriation 
to  the  nutritive  process;  whether  these  substances  be  directly  furnished  by  the 
external  world,  or  be  derived  from  the  disintegration  of  the  organism  itself. 
We  have  seen  that,  in  the  Lacteals,  the  selecting  power  is  such,  that  these 
vessels  are  not  disposed  to  convey  into  the  system  any  substances  but  such  as 
are  destined  for  this  purpose ;  and  that  extraneous  matters  are  absorbed  in  pre- 
ference by  the  mesenteric  Bloodvessels.  The  case  is  different,  however,  with 
regard  to  the  Lymphatics ;  for  there  is  reason  to  believe,  that  they  are  more 
disposed  than  the  veins  to  the  absorption  of  other  soluble  matters,  especially 
when  these  are  brought  into  relation  with  the  Skin,  through  which  the  lymphatic 
vessels  are  very  profusely  distributed. 

3. —  Of  the  Elaboration  of  the  Nutrient  Materials. — Sanguification. 

472. — The  alimentary  substances,  taken  up  by  the  Bloodvessels  and  Absorb- 
ents, seem  very  far  from  being  capable  of  immediate  application  to  the  nutrition 
of  the  body ;  for  we  find  that  they  are  not  conveyed  by  any  means  directly  into 

atics  is  to  remove,  by  interstitial  absorption,  the  effete  matter,  which  is  destined  to  be 
carried  out  of  the  system ;  and  any  undue  activity  in  this  process  (such  as  exists  in  ulcer- 
ation),  and  any  deficiency  in  its  energy  (such  as  gives  rise  to  dropsical  effusions,  and  other 
collections  of  the  same  kind),  have  been  attributed  to  excess  or  diminution  in  the  normal 
operation  of  the  Absorbent  system.  All  that  we  at  present  know,  however,  of  the  process 
of  Nutrition,  tends  to  the  belief  that  the  effete  matters  are  carried  off  by  the  Venous  sys- 
tem; for  not  only  do  we  find  no  trace  in  the  Lymph  of  any  of  those  substances  which  are 
destined  for  elimination  as  excrementitious,  but  the  Lymphatic  vessels  are  either  absent 
altogether,  or  exist  in  but  very  small  numbers,  in  the  Nervo-Muscular  apparatus,  which 
undergoes  more  constant  interstitial  change,  and  produces  more  effete  matter  by  its  disin- 
tegration, than  does  any  other  part  of  the  organism.  It  may  be  safely  affirmed  that  there 
is  not  a  single  fact  to  support  what  is  known  as  the  Hunterian  doctrine ;  which  could  never 
have  gained  currency  but  for  the  authority  of  its  great  teacher — its  originator,  perhaps, 
having  been  rather  Hewson  than  Hunter.  In  the  first  edition  of  this  work,  the  Author 
advanced  the  views  stated  above  in  the  belief  that  they  were  original:  he  has  since  learned, 
however,  that  a  similar  doctrine  had  been  put  forth  by  Dr.  Moultrie,  of  South  Carolina,  in 
the  "Amer.  Journ.  of  Med.  Sci.,"  1827;  and  by  Dr.  Dunglison  in  the  first  Edition  of  his 
"Human  Physiolosry,"  1832. 

29 


450  OF  ABSORPTION   AND    SANGUIFICATION. 

the  circulating  current,  but  that  those  which  enter  the  Gastro-intestinal  veins 
are  submitted  to  the  operation  of  the  Liver ;  whilst  those  which  are  received 
into  the  Lacteals  are  subjected  to  a  kind  of  glandular  action  within  their  own 
system ;  the  newly-absorbed  materials  in  both  cases  undergoing  considerable 
changes,  which  tend  to  assimilate  them  to  the  components  of  the  Blood. — It  will 
be  recollected  that  all  the  veins  which  return  the  blood  from  the  capillaries  of  the 
gastro-intestinal  canal,  converge  into  the  portal  trunk,  which  distributes  this 
blood,  charged  with  the  newly  absorbed  materials,  through  the  capillary  system 
of  the  Liver.  The  agency  of  this  gland  was  formerly  supposed  to  be  limited  to 
the  elimination,  from  the  blood  subjected  to  its  influence,  of  the  materials  of 
the  biliary  secretion;  but  there  is  now  evidence  that  the  blood  itself  is  changed 
by  its  means,  in  a  manner  which  indicates  an  assimilating  as  well  as  a  depurating 
action.  The  blood  which  comes  to  the  Liver  from  the  alimentary  canal,  is 
charged  with  albuminous  matter  in  a  state  different  from  that  of  the  albumen 
of  perfect  blood  (§  167);  and  the  assimilation  of  this  would  appear,  from  the 
observations  and  experiments  of  M.  Cl.  Bernard  formerly  referred  to  (§  169), 
to  be  one  of  the  most  important  functions  of  the  liver.  So,  again,  the  saccha- 
rine matters  which  are  brought  to  the  Liver  in  the  condition  of  grape-sugar  or 
of  cane-sugar,  are  converted  by  its  agency  into  liver-sugar ;  a  form  of  the  sac- 
charine principle,  of  whose  presence  the  blood  is  much  more  tolerant  than  it  is 
of  any  other  (§  45).  From  the  saccharine  compounds  brought  to  the  Liver, 
moreover,  it  appears  that  Fatty  matter  can  be  generated  (§  40);  but  as  the  in- 
troduction of  this  substance  into  the  bloodvessels  ordinarily  takes  place  through 
a  different  channel,  the  action  of  the  liver  would  not  appear  to  be  essential  to 
its  assimilation,  and  it  has  been  found  by  M.  Bernard  that  oil  may  be  injected 
into  the  general  circulation  without  exciting  any  violent  effort  at  its  elimination. 
— There  is  evidence  that  the  Liver  may  be  subservient  even  to  the  vital  trans- 
formation of  the  components  of  the  blood.  For  it  has  been  observed  by  Prof. 
E.  H.  Weber,  that,  during  the  last  three  days  of  incubation  of  the  chick,  the 
liver  is  made  bright  yellow  by  the  absorption  of  the  yolk,  which  fills  and  clogs 
all  the  minute  branches  of  the  portal  veins ;  and  that  in  time  the  materials  of 
the  yolk  disappear,  part  being  developed  into  blood-corpuscles  and  other  constitu- 
ents of  blood,  which  enters  the  circulation,  and  the  rest  forming  bile,  and  being 
discharged  into  the  intestine.1  And  it  is  asserted  by  M.  Bernard  that  the 
quantity  of  fibrin  is  relatively  so  much  greater  in  the  blood  of  the  hepatic  vein, 
than  in  the  portal  blood,  that  the  metamorphosis  of  albumen  into  fibrin  must  be 
admitted  to  be  one  of  the  functions  of  the  liver  ;3 — upon  this  point,  however,  he 
is  by  no  means  in  accordance  with  other  observers. 

473.  The  whole  Absorbent  system  may  be  looked  upon  as  constituting  one 
great  Assimilating  Gland,  dispersed  through  the  body  at  large ;  for  it  does  not 
differ  in  any  essential  particular  from  what  the  Kidney  or  the  Testis  would  be, 
if  it  were  simply  unravelled,  and  its  convoluted  tubuli  spread  through  the  entire 
system,  yet  still  all  discharging  their  secreted  products  by  a  common  outlet.  In 
the  cold-blooded  Vertebrata,  we  find  the  extent  of  its  tubuli  enormously  increased 
by  the  plexuses  which  they  form  around  the  veins ;  so  that  the  Absorbent 
system  appears  to  attain  a  relatively  greater  development  in  them,  than  it  does 
in  the  higher  classes.  But  the  difference  really  lies  in  the  greater  diffusion,  in 
the  former,  of  the  elements  which  are  more  concentrated  in  the  latter.  In 
Birds,  the  plexuses  are  smaller,  and  we  meet  in  them  with  the  "  glands"  or 
"  ganglia,"  of  which  the  Absorbent  system  of  Reptiles  and  Fishes  is  completely 

1  "  Henle  and  Pfeuffer's  Zeitschrift,"  1846. 

2  See,  oh  the  whole  of  this  subject,  M.  Cl.   Bernard's  Lectures  on  the  "Functions  of 
Liver,"  delivered  before  the  College  de  France,  and  published  in  "  L'Union  Medicale"  for 


COMPOSITION   AND   PROPERTIES   OF   THE   CHYLE   AND   LYMPH.     451 


destitute.  And  in  Mammals,  the  plexuses  almost  entirely  disappear,  and  their 
place  is  occupied  by  the  "  glands"  which  are  found  in  the  course  both  of  the 
lacteal  and  lymphatic  Absorbents.  These  bodies,  wherever  they  occur,  have  the 
same  essential  structure;  and  may  be  described  as  consisting  of  convoluted 
knots  of  absorbent  vessels,  their  simple  cylindrical  canals,  however,  being  usually 
dilated  into  larger  cavities  or  "cells"  that  freely  communicate  with  each  other; 
and  capillary  vessels  being  minutely  distributed  among  them.  These  blood- 
vessels have  no  direct  communication  with  the  interior  of  the  absorbents  and 
the  cavities  of  the  glandulae,  being  separated  from  them  by  the  membranous 
walls  of  both  sets  of  tubes  ;  but  there  can  be  no  doubt  that  transudation  readily 
takes  place  from  one  set  of  canals  to  the  other.  The  epithelium,  which  lines 
the  absorbent  vessel,  undergoes  a  marked  change  where  the  vessel  enters  the 
gland;  and,  according  to  Prof.  Goodsir,1  becomes  more  like  that  of  the  proper 
glandular  follicles  in  its  character.  Instead  of  being  flat  and  scale-like,  and 
forming  a  single  layer  in  close  apposition  with  the  basement-membrane,  as  it 

Fig.  136. 


Diagram  of  a  Lymphatic  gland,  showing 
the  intra-glandular  network,  and  the 
transition  from  the  scale-like  epithelia  of 
the  extra-glandular  lymphatics,  to  the 
nucleated  cells  of  the  intra-glandular. 


Portion  of  intra-glandular  Lymph- 
atic showing  along  the  lower  edge 
the  thickness  of  the  germinal  mem- 
brane, and  upon  it  the  thick  layer  of 
glandular  epithelial  cells. 


does  in  the  absorbents  previous  to  their  entrance  into  the  gland  and  after  their 
emergence  from  it  (Fig.  136),  we  find  it  composed  of  numerous  layers  of  spher- 
ical nucleated  cells  (Fig.  137),  of  which  the  superficial  ones  are  easily  detached, 
and  appear  to  be  identical  with  the  cells  found  floating  in  the  Chyle  (§  475). 

474.  Composition  and  properties  of  the  Chyle  and  Lymph. — The  chief  chemi- 
cal difference  between  these  fluids  consists  in  the  much  smaller  proportion  of  solid 
matter  in  the  Lymph,  and  in  the  almost  entire  absence  of  fat,  which  is  an  im- 
portant constituent  of  the  Chyle.  This  is  well  shown  in  the  following  compara- 
tive analyses,  performed  by  Dr.  Gr.  O.  Rees,3  of  the  fluids  obtained  from  the 
lacteal  and  lymphatic  vessels  of  a  donkey,  previously  to  their  entrance  into  the 
thoracic  duct;  the  animal  having  had  a  full  meal  seven  hours  before  its  death. 


Water 

Albuminous  matter  (coagulable  by  heat) 
Fibrinous  matter  (spontaneously  coagulable) 
Animal  extractive  matter,  soluble  in  water  and  alcohol 
Animal  extractive  matter,  soluble  in  water  only    . 

Fatty  matter 

Salts ; — Alkaline  chloride,  sulphate  and  carbonate,  with 
traces  of  alkaline  phosphate,  oxide  of  iron 


Chyle. 
90.237 
3.516 
0.370 
0.332 
1.233 
3.601 

0.711 
100.000 


Lymph. 

96.536 

1.200 

0.120 

0.240 

1.319 

a  trace. 

0.585 
100.000 


1  "  Anatomical  and  Pathological  Observations,"  p.  46. — It  has  recently  been  denied  by 
Prof.  Bennett,  however,  that  these  cells  are  epithelial,  or  given  off  from  a  basement-mem- 
brane such  as  that  described  by  Prof.  .Goodsir  (2  119);  their  formation  being,  in  Prof. 
Bennett's  opinion,  from  nuclei  developed  freely  in  the  midst  of  the  fluid.     (See  "Edinb. 
Monthly  Journ.,  March,  1852,  p.  284.) 

2  "Medical  Gazette,"  Jan.  1,  1841. 


452  OF   ABSORPTION   AND    SANGUIFICATION. 

The  Lymph  obtained  from  the  neck  of  a  horse  has  been  analyzed  by  Nasse,  with 
nearly  the  same  result.  He  found  it  to  contain  95  per  cent,  of  water ;  and  the 
5  per  cent,  of  solid  matter  was  chiefly  composed  of  albumen  and  fibrin,  with 
watery  extractive,  scarcely  a  trace  of  fat  being  discoverable.  The  proportions 
of  saline  matter  were  found  to  be  remarkably  coincident  with  those  which  exist 
in  the  serum  of  the  blood ;  as  might  be  expected  from  the  fact  that  the  fluid 
portion  of  the  lymph  must  have  its  origin  in  that  which  has  transuded  through 
the  bloodvessels  :  the  absolute  quantity,  however,  is  rather  less.  A  similar 
analysis  of  the  Chyle  of  a  cat  by  Nasse,  has  given  results  very  closely  corre- 
spondent with  that  of  Dr.  Rees;  for  the  proportion  of  water  was  90.5  per  cent. ; 
and  of  the  9.5  parts  of  solid  matter,  the  albumen,  fibrin,  and  extractive  amounted 
to  more  than  5,  and  the  fat  to  more  than  3  parts.1 — Dr.  Rees  has  also  analyzed 
the  fluid  of  the  Thoracic  duct  of  Man  ;3  and  found  it  to  consist  of  90.48  per  cent, 
of  water,  7.08  parts  of  albumen  and  fibrin,  1.08  parts  of  aqueous  and  alcoholic 
extractive,  and  0.92  of  fatty  matter,  with  0.44  per  cent,  of  salines.  Thus  the 
composition  of  this  fluid  would  seem  to  resemble  that  of  the  Lymph,  rather  than 
that  of  the  Chyle  ;  the  proportion  of  the  fatty  to  that  of  the  albuminous  matter 
being  very  small.  This,  however,  might  have  been  very  probably  due  to  the 
circumstance,  that  the  subject  from  which  the  fluid  was  obtained  (an  executed 
criminal)  had  eaten  but  little  for  some  hours  before  his  death. 

475.  The  characters  of  the  Chyle  drawn  from  the  larger  absorbent  trunks, 
near  their  entrance  into  the  receptaculum  chyli,  are  very  different  from  those  of 
the  fluid  as  first  absorbed  into  the  Lacteals ;  for  during  its  passage  through  these 
vessels,  and  their  ganglia  or  glands,  it  undergoes  important  alterations,  which 
gradually  assimilate  it  to  Blood.  The  chyle  drawn  from  the  lacteals  that 
traverse  the  intestinal  walls,  contains  Albumen  in  a  state  of  complete  solution; 
but  it  is  generally  destitute  of  the  power  of  coagulation,  no  Fibrin  being  present 
in  it.  The  Salts  also  are  completely  dissolved ;  but  the  Oily  matter  presents 
itself  in  the  form  of  globules  of  variable  size.3  It  is  generally  supposed  that  the 
milky  color  of  the  chyle  is  owing  to  these ;  but  Mr.  Gulliver  has  pointed  out4 
that  it  is  really  due  to  an  immense  multitude  of  far  more  minute  particles,  which 
he  describes  as  forming  the  molecular  base  of  the  chyle.  These  molecules  are 
most  abundant  in  rich,  milky,  opaque  chyle  j  and  in  poorer  chyle,  which  is  semi- 
transparent  or  opaline,  the  particles  float  thinly  or  separately  in  the  transparent 
fluid,  and  often  exhibit  the  vivid  motions  common  to  the  most  minute  molecules 
of  various  substances.  Such  is  their  minuteness,  that,  even  with  the  best  in- 
struments, it  is  impossible  to  form  an  exact  appreciation  either  of  their  form  or 
their  dimensions.  They  seem,  however,  to  be  generally  spherical ;  and  their 
diameter  may  be  estimated  at  between  l-36,000th  and  l-24,000th  of  an  inch. 
Their  chemical  nature  is  as  yet  uncertain  :  they  are  remarkable  for  their  un- 
changeableness,  when  subjected  to  the  action  of  numerous  reagents  which 
quickly  affect  the  proper  Chyle-corpuscles  ;  and  they  are  readily  soluble  in  ether, 
the  addition  of  which  causes  the  whole  molecular  base  instantly  to  disappear,  not 
a  particle  of  it  remaining;  whence  it  may  be  inferred  that  they  consist  of  oily  or 
fatty  matter.  That  they  do  not  ordinarily  tend  to  coalesce,  is  probably  due  to 
the  coating  of  albumen  which  they  obtain  through  their  diffusion  in  an  albuminous 
fluid  (§  42,  note)  j  if,  however,  this  be  dissolved  by  acetic  acid,  or  even  by  the 
addition  of  water,  many  of  the  molecules  are  lost  sight  of,  and  oil-drops  appear 

1  Wagner's  "Handworterbuch,"  Art.  "Chylus." 

2  "  Philosophical  Transactions,"  1842. 

3  These  oily  globules  are  more  abundant  in  the  Chyle  of  Man  and  of  the  Carnivora,  than 
in  that  of  the  Herbivora;  their  diameter  has  been  observed  to  vary  from  l-25,000th  ta 
1 -2000th  of  an  inch. 

4  "Dublin  Medical  Press,"  Jan.  1,  1840,  and  "Gerber's  General  Anatomy,"  Appendix, 
p.  88. 


COMPOSITION   AND   PROPERTIES    OF   THE    CHYLE   AND   LYMPH.     453 

in  their  place.  The  milky  color,  which  the  serum  of  blood  sometimes  exhibits 
in  healthy  subjects,  is  due  to  an  admixture  of  this  molecular  base  with  the  circu- 
lating fluid  ($41). 

476.  During  the  passage  of  the  Chyle  through  the  absorbents  on  the  intes- 
tinal edge  of  the  Mesentery,  towards  the  Mesenteric  Glands,  its  character 
changes  in  several  important  particulars.  The  presence  of  Fibrin  begins  to 
manifest  itself,  by  the  slight  coagulability  of  the  fluid  when  withdrawn  from 
the  vessels;  and  while  this  ingredient  increases,  the  Albumen  and  the  Oil- 
globules  gradually  diminish  in  amount.  The  Chyle  drawn  from  the  neighbor- 
hood of  the  mesenteric  glands  exhibits  the  Corpuscles  regarded  as  characteristic 
of  that  fluid;  these  are  peculiarly  abundant  in  the  fluid  drawn  from  the  glands 
themselves;  and  they  are  constantly  found  in  it,  through  its  whole  subsequent 
course.  The  Chyle  corpuscles  are  much  larger  than  the  molecules  just  described, 
and  an  examination  of  their  character  presents  no  difficulty.  Their  diameter 
varies  from  l-7110th  to  l-2600th  of  an  inch;  the  average  being  about  l-4600th. 
They  are  usually  minutely  granulated  on  the  surface,  seldom  exhibiting  distinct 
nuclei,  even  when  treated  with  acetic  acid ;  but  sometimes  three  or  four  central 
particles  may  be  distinguished  within  them.  They  correspond  in  all  essential 
particulars  with  the  Colorless  Corpuscles  of  the  Blood  (§  145),  but  appear  to  be 
in  an  earlier  stage  of  formation.  During  the  passage  of  the  Chyle  through  the 
mesenteric  glands,  a  further  increase  in  the  proportion  of  Fibrin  takes  place ; 
and  the  resemblance  of  the  fluid  to  Blood  becomes  more  apparent.  The  Chyle 
drawn  from  the  vessels  intermediate  between  these  and  the  central  duct,  pos- 
sesses a  pale,  reddish-yellow  color ;  and,  when  allowed  to  stand  for  a  time,  under- 
goes a  regular  coagulation,  separating  into  clot  and  serum.  The  former  is  a 
consistent  gelatinous  mass,  which,  when  examined  with  the  microscope,  is  found 
to  include  the  Chyle-corpuscles,  each  of  them  being  surrounded  by  a  delicate 
film  of  oil :  the  Fibrin  of  which  it  is  principally  composed,  differs  remarkably 
from  that  of  the  blood,  in  its  inferior  tendency  to  putrefaction;  whence  it  may 
be  inferred  that  it  has  not  yet  undergone  its  complete  vitalization.  The  serum 
contains  the  Albumen  and  Salts  in  solution,  and  a  proportion  of  the  Chyle-cor- 
puscles suspended  in  it.  It  is  curious,  however,  that  considerable  differences  in 
the  perfection  of  the  coagulation,  and  in  its  duration,  should  present  themselves 
in  different  experiments.  Sometimes  the  chyle  sets  into  a  jelly-like  mass,  which, 
without  any  separation  into  coagulum  and  serum,  liquefies  again  at  the  end  of 
half  an  hour,  and  remains  in  this  state.  This  change  takes  place  in  the  true 
coagulum  also,  if  it  be  kept  moist  for  a  sufficient  length  of  time. — The  Chyle 
from  the  Receptaculum  and  Thoracic  Duct  coagulates  quickly,  often  almost 
instantaneously ;  and  few  or  none  of  the  corpuscles  remain  in  the  serum.  The 
fluid  drawn  from  the  Thoracic  Duct,  and  from  the  Absorbent  vessels  which 
empty  their  contents  into  it,  is  frequently  observed  to  present  a  decided  red 
tinge,  which  increases  on  exposure  to  the  air.  This  tinge  appears  to  be  due  to 
the  presence  of  Red  blood-corpuscles  in  an  early  stage  of  formation  (§  150). 
The  ordinary  corpuscles,  moreover,  have  a  more  distinctly  cellular  character, 
than  have  those  of  the  chyle  and  lymph;  and  they  are  of  larger  size,  their 
diameter  usually  ranging  from  about  l-2600th  to  l-2900th  of  an  inch.  In 
these  particulars,  they  correspond  with  the  Colorless  corpuscles  of  the  Blood ; 
as  also  in  the  change  they  exhibit  on  the  action  of  acetic  acid,  which  brings 
into  view  three  or  four  large  central  particles.  The  following  table,  slightly 
modified  from  that  of  Gerber,1  presents  in  a  concise  form  a  view  of  the  rela- 
tive proportions  of  the  three  chief  ingredients  in  the  Chyle,  in  different  parts 
of  the  absorbent  system,  and  thus  gives  an  idea  of  its  advance  in  the  process  of 
assimilation. 

1  "General  Anatomy,"  edited  by  Gulliver,  p.  49. 


454  OF   ABSORPTION   AND    SANGUIFICATION. 

In  the  afferent  or  peripheral   f  Fat,  in  maximum  quantity  (numerous  fat  or  oil-globules). 
Lacteals  (from  the  Intes-   I  Albumen  in  medium  quantity, 
tines  to  the  Mesenteric  1  Few  or  no  Chyle-corpuscles, 
glands).  [  Fibrin  almost  entirely  wanting. 

In  the  efferent   or  central   f  Fat,  in  medium  quantity  (fewer  oil-globules). 
Lacteals  (from  the  Mes-  J  Albumen  in  maximum  quantity. 

enteric    glands    to    the  1  Chyle-corpuscles  very  numerous,but  imperfectly  developed. 
Thoracic  Duct).  [  Fibrin  in  medium  quantity. 

f  Fat,  in  minimum  quantity  (fewer  or  no  oil-globules). 
m,         .    ,,.  Albumen  in  medium  quantity. 

j  Chyle-corpuscles  numerous,  and  more  distinctly  cellular. 
[  Fibrin  in  maximum  quantity. 

477.  The  aspect  of  the  Lymph  greatly  differs  from  that  of  the  Chyle,  the  former 
being  nearly  transparent,  while  the  latter  is  opaque  or  opalescent ;  and  this 
difference  is  readily  accounted  for,  when  the  assistance  of  the   microscope  is 
sought,  by  the  entire  absence  from  the  Lymph  of  that  "molecular  base"  which 
is  so  abundant  in  the  Chyle.     A  considerable  number  of  corpuscles  are  gene- 
rally present  in  it;  and  these,  like  the  chyle-corpuscles,  correspond  in  all  re- 
spects with  the  colorless  corpuscles  of  the  Blood  (§  145).     Their  amount,  how- 
ever, is  extremely  variable ;  as  is  also  that  of  the  oil-globules,  which  sometimes 
occur,  whilst  in  other  instances  none  can  be  discovered.     Lymph  coagulates  like 
chyle ;  a  colorless  clot  being  formed,  which  incloses  the  greater  part  of  the  cor- 
puscles. 

478.  The  fluid  drawn  from  the  Thoracic  Duct,  consisting  as  it  does  of  an 
admixture  of  Chyle  and  Lymph,  will  probably  vary  in  its  character  and  com- 
position, according  to  the  predominance  of  the  former,  or  of  the  latter,  of  these 
constituents. — From  some  observations  made  by  Bidder1  on  the  quantity  of 
fluid  discharged  from  the  thoracic  ducts  of  dogs  and  cats  immediately  after 
death,  it  is  inferred  by  him  that  the  total  amount  of  mingled  lymph  and  chyle 
which  is  daily  poured  into  the  circulating  current,  is  equal  in  bulk  to  at  least 
two-thirds  the  entire  mass  of  the  blood ;  though  it  furnishes,  bulk  for  bulk,  not 
more  than  from  one-fourth  to  one-third  the  quantity  of  solid  matter  which  the 
blood  contains.     It  is  difficult  to  suppose,  however,  that  so  large  a  quantity 
really  enters  the  circulating  current  through  this  channel,  in  addition  to  that 
which  is  taken  up  by  the  veins ;  and  it  is  obvious  that  there  are  many  circum- 
stances which  prevent  the  results  of  such  observations  from  being  fairly  assumed 
as  furnishing  an  average  for  the  entire  day. 

479.  The  movement  of  the  fluids  taken  up  by  the  Absorbent  vessels  seems 
to  depend  upon  a  combination  of  different  agencies.     The  lower  Vertebrata  are 
provided  with  "lymphatic  hearts/7  or  pulsatile  cavities,  by  which  important 
assistance  is  given  in  the  onward  flow;  but  no  such  aid  is  afforded  in  Man  or  in 
the  Mammalia ;  yet  it  is  obvious  that  a  considerable  vis  d  tergo  must  exist,  since, 
if  the  thoracic  duct  be  tied,  it  is  speedily  distended  below  the  ligature,  even  to 
bursting.     The  Absorbent  vessels,  like  the  veins,  have  a  fibrous  coat,  into  which 
the  muscular  fibre-cells  enter  largely,  and  which  is  therefore  contractile ;  and  it 
has  been  found  by  Prof.  Kblliker,  that  when  the  wire  of  an  electro-magnetic 
apparatus  was  applied  to  some  well-filled  lymphatics  on  the  skin  of  a  boy's  foot, 
soon  after  the  removal  of  his  leg  by  amputation,  the  stimulus  occasioned  a  dimi- 
nution in  their  diameter  by  at  least  one-half,  and  this  not  suddenly,  but  in  the 
course  of  between  half  a  minute  and  a  minute.3     The  same  excellent  observer 
has  observed  that  the  lymphatic  vessels  in  the  tail  of  a  Tadpole  empty  them- 
selves by  contraction  after  death,  and  then  dilate  again  to  their  former  size,  just 
as  the  smaller  arteries  do  under  the  like  circumstances;9  and  this  fact  is  in  ac- 

'  "  Mailer's  Archiv.,"  1845.  2  «  Kulliker  and  Siebold's  Zeitschrift,"  1849. 

3  "  Annales  des  Sciences  Naturelles,"  1840,  Zool.,  torn.  vi.  p.  99. 


COMPOSITION   AND   PROPERTIES    OF  THE   CHYLE   AND   LYMPH.     455 

cordance  with  the  emptiness  of  the  Absorbent  system,  which  usually  presents 
itself  in  Man  some  little  time  after  death.  Hence  it  seems  probable  that  regular 
propulsion  of  the  fluid  during  life  may  be  effected  by  alternate  contractions  and 
dilatations  of  successive  portions  of  the  vessels,  slowly  repeated  at  intervals.1 — 
There  are,  however,  certain  auxiliary  forces.  For,  in  the  first  place,  a  part  of 
the  movement  may  be  attributed  to  the  vis  a  tergo,  which  is  produced  by  the 
continual  introduction  of  fresh  fluid  into  the  rootlets,  so  to  speak,  of  the  vascu- 
lar tree ;  and  this  more  especially  in  the  case  of  the  lacteals,  since  the  muscularity 
of  the  villi  seems  to  enable  them  to  act  as  so  many  minute  force-pumps,  whereby 
the  fluid  which  they  have-  imbibed  may  be  impelled  onwards  (§  460).  It  may 
be  thought  that,  from  the  extreme  distensibility  of  the  walls  of  the  absorbents, 
this  force  would  be  rather  expended  in  dilating  them,  than  in  pushing  on  the 
current  of  liquid  which  they  contain ;  but  it  must  be  borne  in  mind  that  they 
are  for  the  most  part  closely  surrounded  with  tissues  which  exert  a  certain  degree 
of  pressure  upon  them,  and  that  this  is  much  greater  during  life  than  after 
death.  Further,  in  all  the  movable  parts  of  the  body,  assistance  is  doubtless 
afforded  (as  it  is  to  the  circulation  in  the  Veins,  CHAP.  ix.  SECT.  4)  by  the  oc- 
casional pressure  exercised  upon  the  Absorbents  by  the  surrounding  tissues ;  for 
while  this  pressure  is  operating  it  will  tend  to  empty  them  of  their  contents, 
which  are  only  permitted  by  their  valves  to  pass  in  one  direction ;  and  when  the 
pressure  is  relaxed,  they  will  be  refilled  from  behind. 

480.  It  seems  obvious,  from  what  has  been  stated,  that  we  are  to  regard  the 
entire  Absorbent  system  as  a  great  blood-making  gland  (§  473),  designed  to 
exert  a  certain  power  of  conversion  or  vitalization  over  the  matters  which  enter 
it,  either  from  the  alimentary  canal  or  from  the  body  in  general. — In  the  case 
of  the  Lacteal  portion  of  the  system,  there  seems  to  be  a  strong  indication  that 
one  part  of  the  converting  process  consists  in  the  intimate  admixture  which  the 
albuminous  constituent  of  the  chyle  undergoes  with  its  fatty  constituent,  owing 
to  the  subdivision  of  the  latter,  and  its  diffusion  through  an  albuminous  fluid. 
And  the  effects  of  this  admixture  are  peculiarly  shown  by  the  tenacity  with 
which  fat  is  incorporated  with  albumen  and  fibrin  (§§  20,  25),  so  that  it  is  dif- 
ficult to  separate  them ;  this  incorporation,  it  seems  probable,  having  a  peculiar 
reference  to  the  very  first  process  of  cytogenesis,  in  which  molecules  of  fatty 
matter  seem  always  to  be  present  in  close  collocation  with  albuminous  particles 
(§  42).  As  already  pointed  out,  the  "plasticity"  of  the  different  albuminous 
compounds  holds  such  a  direct  relation  to  the  quantity  of  fat  they  contain 
(within  certain  limits),  that  we  can  scarcely  help  looking  at  this  incorporation 
as  one  of  the  most  important  parts  of  the  assimilating  process.  And  thus  it 
seems  to  be,  that  the  presence  of  fatty  matters  in  the  food  is  essential  to  healthy 
nutrition  (§  404,  in.);  for  no  production  of  fat  by  the  agency  of  the  liver  can 
bring  the  raw  albumen  into  the  same  intimate  relationship  with  the  minutely- 
divided  fatty  molecules.  What  other  changes  the  fluid  of  the  lacteals  may 
undergo,  in  addition  to  the  production  of  fibrin  and  of  corpuscles  which  has 
been  already  noticed,  and  what  is  the  special  purpose  of  the  elaboration  to  which 
the  fluid  of  the  Lymphatics  is  subjected,  cannot  as  yet  be  distinctly  stated. 
Probably,  however,  the  changes  in  question  are  less  of  a  chemical  than  of  a  vital 
nature,  and  are  such  as  serve  to  prepare  the  fluid  for  maintaining  the  vital  acti- 
vity of  the  several  parts  of  the  organism  to  which  it  is  to  be  distributed. 

x  A  regular  rhythmical  movement  of  the  veins  of  the  Bat's  wing,  obviously  dependent 
upon  their  independent  contractility,  has  lately  been  observed  by  Mr.  Wharton  Jones 
("  Proceedings  of  the  Royal  Society,"  Feb.  5,  1852).  The  existence  of  such  a  movement 
in  the  Veins  of  a  part,  as  an  auxiliary  propulsive  force,  obviously  strengthens  the  proba- 
bility of  its  occurrence  in  the  Lymphatics,  as  the  principal  propelling  power,  where  no 
central  impulsive  organ  exists ;  just  as  a  like  movement  is  seen  in  the  bloodvessels  of 
such  of  the  lower  Invertebrata  as  have  no  heart. 


456  OF    ABSORPTION   AND    SANGUIFICATION. 

481.  Ductless  Glands. — There  is  reason  to  believe  that  a  similar  office  is  per- 
formed by  certain  bodies  connected  with  the  Circulating  system,  which  possess 
the  essential  elements  of  the  Glandular  structure,  without  any  efferent  ducts ; 
these  must  restore  to  the  circulating  current  any  substances  which  they  may 
withdraw  from  it;  and  there  seems  adequate  ground,  therefore,  for  the  conclu- 
sion, that  their  action,  whatever  it  may  be,  is  subsidiary  to  the  completion  of 
the  process  of  Sanguification — being  exercised,  perhaps,  upon  that  portion  of 
the  nutrient  materials  more  especially,  which  did  not  traverse  the  Absorbent 
system  when  first  introduced,  but  which  was  directly  taken  up  by  the  blood- 
vessels.    The  organs  in  question,  which  have  received  the  distinctive  appellation 
of  Vascular  or  Ductless  Glands,  are  the  Spleen,  the  Thymus,  Thyroid,  and  Supra- 
renal bodies.     Of  these,  the  Spleen   deserves  especial  notice,  on  account  of  its 
size  and  obvious  functional  importance  in  the  adult ;  the  others  appear  to  minis- 
ter more  particularly  to  the  requirements  of  the  system  at  the  earlier  periods  of 
life. 

482.  The  minute- structure  of  the  Spleen  has  recently  been  made  the  subject 
of  careful  research  by  many  excellent  Microscopic  observers ;  and  more  espe- 
cially Prof.  Kb'lliker1  and  by  Dr.  Sanders.3     The  following  is  a  summary  of  the 
most  important  points  which  they  may  be  considered  to  have  determined. 

I.  The  fibrous  coat  in  Man  is  composed  of  white  fibrous  tissue,  with  an  inter- 
mixture of  yellow  or  elastic  fibres;  in  many  of  the  lower  animals,  however,  it 
contains  non-striated  muscular  fibres  composed  of  fusiform  fibre-cells. 

II.  The  trabecular  tissue  consists  of  fibrous  bands,  and   threads  which  arise 
from  the  inner  surface  of  the  fibrous  envelop,  and  form  a  network  that  extends 
through  the  entire  organ,  becoming  connected  also  with  the  fibrous  sheaths  of 
the  vessels  which  penetrate  it.     These  bands  are  partly  muscular  in  the  animals 
which  have  muscular  fibres  in  the  external  envelop  of  the  spleen;  but  elsewhere 
they  are  simply  fibrous.     The  spaces  left  by  their  intersection,  which  are  by  no 
means  regular  either  as  to  form  or  size,  are  occupied  by  the  splenic  corpuscles 
and  splenic  parenchyma.     In  the  trabeculae  of  the  human  spleen,  Prof.  K.  has 
discovered  some  peculiar  fusiform  cells  with  round  nuclei,  which  are  probably  to 
be  considered  as  contractile  cells  not  developed  into  their  properly  characteristic 
form  (§  305). 

in.  The  peculiar  Splenic  Corpuscles,  sometimes  termed  the  "  Malpighian  cor- 
puscles" of  the  Spleen,  are  whitish  spherical  bodies,  which  are  imbedded  in  the 
splenic  parenchyma,  but  are  connected  with  the  smaller  arteries  by  short  pedun- 
cles, like  grapes  with  their  fruit-stalks,  or  are  sessile  upon  their  sheaths.  Owing 
to  the  rapid  changes  which  they  undergo  after  death,  and  the  influence  of  pre- 
vious disease  and  abstinence,  they  are  seldom  seen  in  the  Human  subject,  but 
are  best  seen  in  the  perfectly  fresh  spleens  of  the  Ruminantia ;  there  is  no  doubt, 
however,  of  their  invariable  presence  in  the  healthy  human  subject,  although 
this  has  been  denied  by  many  anatomists.  The  size  of  these  corpuscles,  when 
fully  developed,  varies  from  about  l-3d  to  l-6th  of  a  line;  smaller  bodies,  how- 
ever, are  met  with,  which  appear  to  be  Malpighian  corpuscles  in  an  earlier  stage 
of  evolution.  Each  of  them  consists  of  a  delicate  fibrous  envelop,  derived  from 
the  sheath  of  the  artery  to  which  it  is  attached,  and  frequently  surrounded  by 
capillaries  of  extreme  minuteness.  It  contains,  as  its  constant  and  essential 
elements,  nucleated  cells  of  from  l-6000th  to  l-4000th  of  an  inch  in  diameter, 
pale  and  faintly  granular,  together  with  free  nuclei  (the  proportion  of  which  to 
that  of  the  fully-formed  cells  is  extremely  variable),  and  a  few  of  larger  size, 
and  more  distinctly  granular  before  the  addition  of  reagents,  from  1-3 500th  to 

1  "Cyclopaedia  of  Anatomy  and  Physiology,"  Art.  "Spleen;"  and  "  Mikroskopische 
Anatomic,"  band  ii.  gg  183 — 189. 

2  "Annals  of  Anatomy  and  Physiology,"  No.  1. 


OF   THE   DUCTLESS   GLANDS:  —  THE    SPLEEN.  457 

l-3000th  of  an  inch  in  diameter.  Besides  these  and  other  varieties  of  cells  con- 
tained in  the  Malpighian  corpuscles,  Dr.  Sanders  describes  a  peculiar  set  of 
spherical  cells,  of  a  bright  golden  color,  usually  from  l-1200th  to  l-1500th  of 
an  inch  in  size,  each  having  a  single  nucleus;  which  cells  form  a  regular  layer 
beneath  the  capsule.  Among  these  are  seen  other  cells  of  1-1 000th  of  an  inch 
or  more  in  diameter,  containing  two  or  three  nuclei;  and  yellow  globules  of  all 
diameters  from  14000th  to  l-12000th  of  an  inch,  which  are  probably  either 
free  nuclei  or  young  cells  of  this  class.  Between  the  corpuscular  contents  of 
the  Malpighian  corpuscles,  there  intervenes  a  homogeneous  or  slightly  granular 
plasma. — The  remarkable  discovery  has  recently  been  made  by  Dr.  Sanders,  that 
the  interior  of  the  Malpighian  corpuscles  is  traversed  (like  that  of  the  Peyerian 
vesicles,  §  456)  by  arterial  twigs  of  considerable  size;  which  may  be  demon- 
strated by  boiling  the  tissue  in  acidulated  water,  drying  it,  and  then  cutting  thin 
sections.1 — Many  observers  have  affirmed  that  there  is  some  special  connection 
between  the  Malpighian  corpuscles  and  the  Lymphatics  of  the  spleen ;  but  it 
may  be  considered  as  quite  determined  by  the  concurrence  of  the  most  recent 
observations  on  this  point,  that  no  such  communication  exists. 

IV.  The  true  Splenic  Parenchyma  consists  in  great  part  of  cells,  which  cor- 
respond in  appearance  with  those  of  the  Malpighian  corpuscles,  and  which  are, 
like  them,  imbedded  in  a  nearly  homogeneous  plasma ;  but  two  other  kinds  of 
cells  occur  in  it,  which  are  seldom  met  with  in  the  latter;  and  numerous  free 
nuclei  are  also  present.     Of  these  two  kinds  of  cells,  one  set  is  smaller,  and  the 
other  larger,  than  the  average  of  the  parenchymatous  cells;  the  former  bear  a 
strong  resemblance  to  red  blood-corpuscles,  but  are  of  a  paler  color;  the  latter 
are  partly  pale  cells,  of  1-1 700th  of  an  inch  in  diameter,  with  one  or  two 
nuclei,  or  granule-cells  of  from  l-3000th  to  l-2000th  of  a  line,  which  may 
be  described  as  "colorless  granule-cells." — These  elements  of  the  pulp,  like  the 
contents  of  the  Malpighian  corpuscles,  vary  greatly  in  their  proportions  to  each 
other;  from  which  it  may  be  concluded  that  they  are  in  a  state  of  continual 
development  and  degeneration.     They  do  not  lie  collected  in  large  heaps,  but 
form  small  irregular  groups  of  different  sizes,  which  are  clustered  especially  on 
the  sheaths  of  the  vessels,  the  trabecular  partitions,  and  the  membranes  of  the 
Malpighian  corpuscles ;  they  are  not  themselves  included,  however,  in  special 
envelops. — Besides  the  usual  corpuscles  and  granules  of  the  parenchyma,  it 
contains  dispersed  through  it,  in  very  inconstant   amount,  some  remarkable 
colored  particles,  varying  from  the  size  of  small  granules  to  that  of  blood-corpus- 
cles, and  often  aggregated  in  masses  of  l-1000th  of  an  inch  in  diameter,  having 
a  distinct  envelop  which   sometimes   contains  as  many  as  twenty  corpuscles. 
These  are  probably,  as  asserted  by  Kolliker,  blood-corpuscles  in  various  stages 
of  degeneration;  but  they  are  by  no  means  peculiar  to  the  spleen,  for  they  present 
themselves  in  many  other  situations  where  extravasations  of  blood  occasionally 
occur  ;  and,  as  remarked  by  Dr.  Sanders,  "  from  all  the  circumstances  connected 
with  them,  they  would  appear  to  be  the  product,  not  of  organic  processes,  but  of 
physical  alteration  in  stagnant  blood,  and  are  only  more  abundant  in  the  spleen, 
because  more  blood  is  retained  after  death  in  its  pulp,  than  in  the  substance  of 
other  organs." 

V.  Of  the  Splenic  Arteries,  it  is  chiefly  to  be  observed  that  their  branches 
form  no  anastomoses,  but  that  they  subdivide  and  ramify  like  the  branches  of  a 
tree,  with  the  Malpighian  corpuscles  attached  to  them  as  fruit.     Beyond  their 
connection  with  these,  however,  they  enter  into  the  red  spleen  substance;  and 
here  each  twig  subdivides  into  a  tuft  of  arteries  still  more  minute,  which  again 
subdivide  into  the  true  capillaries  that  constitute  a  close  and  beautiful  network 
in  the  splenic  pulp. — Of  the  Veins,  it  is  positively  affirmed  by  Prof.  Kolliker, 

1  See  "  Edinburgh  Monthly  Journal,"  March,  1852,  p.  286. 


458  OF   ABSORPTION   AND   SANGUIFICATION. 

that  the  idea  long  entertained  as  to  their  dilatation  into  cavernous  spaces  or 
sinuses  is  incorrect,  so  far  as  the  Human  spleen  is  concerned;  and  that  there  is 
nothing  peculiar  in  their  distribution,  save  in  their  mode  of  ramification,  which 
closely  resembles  that  of  the  arteries,  and  in  the  absence  of  valves.  In  the  spleen 
of  the  Ox,  however,  and  of  other  Ruminants  a  true  cavernous  structure  does 
exist.  * 

VI.  The  Lymphatics  of  the  Spleen  are  few  and  inconsiderable  in  Man ;  being 
less  numerous  than  in  other  glandular  organs,  such  as  the  liver  and  kidneys. 
In  some  of  the  lower  animals  they  are  more  abundant  ;  but  even  here  they  are 
mostly  superficial,  and  scarcely  penetrate  to  the  interior  of  the  organ. 

Vii.  The  Nerves  of  the  Spleen  are  apparently  very  large  in  some  animals, 
especially  in  the  Ruminants;  but  the  great  size  of  their  trunks  and  branches  is 
chiefly  due  to  the  large  proportion  of  ordinary  fibrous  tissue  which  enters  them; 
the  number  of  real  nerve-fibres  being  extremely  small. 

483.  The  history  of  the  development  of  the  Spleen,  which  has  been  recently 
studied  with  great  care  by  Mr.  H.  Gray,1  presents  facts  of  great  interest,  as 
aiding  in  the  determination  of  the  functional  character  of  this  organ,  and  of  the 
nature  of  its  component  parts. — It  arises  in  the  Chick  between  the  4th  and  5th 
days  of  incubation,  in  a  fold  of  membrane  which  connects  the  intestinal  canal 
to  the  spine  (the  "intestinal  lamina"),  as  a  small  whitish  mass  of  blastema,  per- 
fectly distinct  from  both  the  stomach  and  the  pancreas;  from  the  former  of 
which  it  has  been  said  by  Bischoff,  and  from  the  latter  by  Arnold,  to  take  its 
origin.     The  external  capsule  and  the  trabecular  tissue  are  developed  between 
the  8th  and  9th  days;  the  former  as  a  thin  membrane  composed  of  nucleated 
fibres,  the  latter  consisting  of  similar  fibres  which  intersect  the  organ  at  first 
sparingly,  and  afterwards  in  greater  quantity.     The  bloodvessels  of  this  organ 
are  formed  within  itself,  independently  of  those  which  are  exterior  to  it ;  and 
blood-corpuscles  are  also  observed  to  originate  in  the  substance  of  its  blastema, 
their  formation  continuing  until  its  connection  with  the  general  vascular  system 
is  completed,  at  which  period  their  development  appears  to  cease. — The  pulp- 
tissue,  at  an  early  period  of  its  formation,  closely  corresponds  with  that  of  the 
supra-renal  and  thyroid  bodies  in  their  earliest  stages  of  evolution ;  consisting  of 
nuclei,  nucleated  vesicles,  and  a  fine  granular  plasma.     When  the  splenic  vessels 
are  formed,  many  of  these  nuclei  are  surrounded  by  a  quantity  of  fine  dark  granules 
arranged  in  a  circular  form;  and  these  increase  up  to  the  time  when  the  splenic 
vein  is  formed,  when  nearly  the  whole  mass  is  composed  of  nucleated  vesicles, 
the  nuclei  of  which  gradually  break  up  into  a  mass  of  granules  which  fill  the 
cavities  of  the  vesicles.     The  Malpighian  vesicles  are  developed  in  the  pulp,  by 
the  aggregation  of  nuclei  into  circular  masses,  around  which  a  fine  membrane 
soon  appears,  in  a  manner  precisely  similar  to  those  of  the  supra-renal  (§  485) 
and  thyroid  'bodies. 

484.  The  Supra-Renal  bodies  in  Man  and  most  Mammalia  present,  like 
the  kidneys,  a  division  into  cortical  and  medullary  substances ;    the   former 
having  a  lighter  hue  than  the  latter.       The  cortical  substance  is  principally 
formed  of  closed  vesicles,  which  are  arranged  in  linear  series  (so  as  to  present 
the  appearance  of  radiating  tubes),  and  which  are  united  by  ensheathing  coats, 
derived  from  processes  of  the  fibrous  envelop.       According  to  Ecker,3  who  is 
confirmed  on  this  point  by  Frey,3  these  vesicles  always  remain  distinct ;  but  Mr. 
Gray  appears  to  think  that  there  is  sometimes  an  absolute  coalescence  between 
them  (§  485).     The  diameter  of  the  vesicles  varies  from  about  1-1 500th  to 
l-800th  of  an  inch ;  and  some  of  them  have  a  length  of  from  l-650th  to  l-480th 

1  "  Proceedings  of  the  Royal  Society,"  Jan.  15,  1852. 

2  "  Annales  des  Sciences  Naturelles,"  Aug.  1847. 

3  "Cyclopaedia  of  Anatomy  and  Physiology,"  Art.  "Supra-renal  Capsules." 


OP   THE   DUCTLESS   GLANDS:  —  THE   SPLEEN.  459 

of  an  inch.  The  contents  of  these  vesicles  are  (1)  a  finely-granular  plasma  rich 
in  albumen,  (2)  nuclear  corpuscles,  usually  from  l-3000th  to  1 -4000th  of  an  inch 
in  diameter,  (3)  cells  of  from  1 -2000th  to  l-1350th  of  an  inch  in  diameter,  whose 
membrane  seems  to  be  formed  by  a  sort  of  precipitation  of  the  granules  upon  the 
nuclei,  and  (4)  fatty  particles  of  various  sizes,  the  proportion  of  which  varies. 
Besides  the  fully-formed  vesicles,  the  parenchyma  also  contains  numerous  iso- 
lated cells,  which  have  been  thought  to  be  vesicles  in  an  earlier  stage  of  deve- 
lopment, but  which  would  appear,  from  the  observations  of  Mr.  Gray  (§  485),  to 
be  rather  cells  as  yet  unclosed  in  vesicles. — The  Medullary  substance,  when 
thin  slices  of  it  are  examined,  is  found  to  be  considerably  more  transparent  than 
the  cortical ;  this  being  due  to  the  absence  of  fat-particles  from  its  substance. 
It  does  not  contain  any  glandular  vesicles;  but  consists  entirely  of  a  basis  of 
fibrous  tissue,  which  is  formed  by  processes  that  come  off  from  the  sheath  of  the 
cortical  substance,  and  which  contains  numerous  bloodvessels  and  nerves.  The 
interspaces  of  this  tissue,  however,  are  occupied  by  a  granular  plasma,  in  which 
are  nuclei  and  cells  in  various  stages  of  development.  The  cortical  substance 
has  a  much  larger  supply  of  blood  than  the  medullary;  for  each  of  the  gland- 
vesicles  is  surrounded  by  a  network,  of  arterial  capillaries  with  long  meshes, 
derived  from  primitive  branches  of  the  supra-renal  arteries ;  whilst  other  branches 
pass  at  once  towards  the  medullary  substance,  and  there  break  up  into  twigs, 
which  return  by  devious  paths  into  the  cortical  mass,  there  to  end  in  a  capillary 
network.  This  superiority  in  vascularity  evidently  has  reference  to  the  greater 
functional  activity  of  the  cortical  substance.  The  supra-renal  capsules  are  by 
no  means  copiously  supplied  with  Lymphatics ;  indeed,  it  is  doubtful  whether 
these  vessels  penetrate  their  interior.  The  nerves  of  these  organs  (which  are 
all  derived  from  the  plexuses  of  the  Sympathetic  system)  are  particularly  nume- 
rous ;  no  such  supply  being  possessed  by  any  similar  organs.1 

485.  The  development  of  the  Supra-Renal  bodies  also  has  been  studied  by  Mr. 
Gray  (loc.  cit.).  He  states  that  they  arise  on  the  7th  day  of  incubation  as  two 
separate  masses  of  blastema,  situated  between  the  upper  end  of  the  Wolffian 
bodies  and  the  sides  of  the  aorta,  being  totally  independent  (as  concerns  their 
development)  of  those  bodies  or  of  each  other.  At  this  period,  their  minute 
structure  bears  a  close  resemblance  to  that  of  the  spleen,  consisting  of  the  same 
elements  as  that  gland,  excepting  in  the  existence  of  more  numerous  dark  gran- 
ules, which  give  to  the  organ  at  a  later  period  an  opaque  and  darkly  granular 
texture.  The  gland-tissue  of  the  organ,  in  the  form  of  large  vesicles,  makes  its 
appearance  on  the  8th  day ;  and  is  evolved  in  the  same  manner  as  that  of  the 
spleen,  namely,  by  an  aggregation  of  nuclei  into  circular  masses,  around  which  a 
limitary  membrane  ultimately  forms.  These  are  at  first  uniformly  grouped 
together,  without  any  subdivision  into  cortical  and  medullary  portions ;  but  on 
the  14th  day,  the  first  trace  of  this  subdivision  becomes  manifest,  by  the  aggre- 
gation of  the  vesicles  into  masses  which  radiate  from  the  circumference  towards 
.the  centre  of  the  gland;  complete  tubes  being  sometimes  formed  by  the  junction 
of  the  vesicles,  as  indicated  by  the  hemispherical  bulgings  on  their  walls.  At 
a  later  period,  the  organs  increase  in  size,  and  attain  their  usual  position ; 
and  a  more  complete  subdivision  into  cortical  and  medullary  portions  is  observed. 
— The  earlier  appearance  of  the  vesicular  structure  of  these  bodies,  as  compared 
with  that  of  the  Malpighian  bodies  of  the  spleen,  is  a  fact  of  much  interest, 
when  considered  with  reference  to  the  period  of  greatest  functional  activity  in 

1  It  is  a  curious  observation,  which  has  been  recently  made  by  M.  Brown-Sequard,  that 
injuries  to  the  Spinal  Cord  in  the  dorsal  region,  occasion  congestion  and  (after  a  time) 
hypertrophy  of  the  supra-renal  capsules  ("  Gazette  Medicale,"  Fevr.  1,  1852).  It  is  no 
objection  to  the  idea  that  this  change  is  dependent  upon  nervous  agency,  that  no  spinal 
nerves  proceed  to  these  organs ;  since  we  know  that  a  large  number  of  spinal  fibres  enter 
the  parts  of  the  Sympathetic  system  whence  they  receive  their  supply. 


460  OF   ABSORPTION   AND    SANGUIFICATION. 

the  two  organs  respectively.  For  the  Supra- Renal  bodies  attain  a  very  large 
size  in  foetal  life,  surpassing  the  Kidneys  in  dimension  up  to  the  tenth  or  twelfth 
week  of  Human  embryonic  development ;  though  they  afterwards  diminish  so 
much,  relatively  to  the  Kidneys,  as  to  possess  in  the  adult  condition  only  1-2 8th 
part  of  their  bulk. 

486.  The  elementary  structure  of  the  Thymus  Gland  may  be  best  understood 
from  the  simple  form  it  presents,  when  it  is  first  capable  of  being  distinguished 
in  the  embryo.  It  then  consists  of  a  single  tube,  closed  at  both  ends,  and  filled 
with  granular  matter;  and  its  subsequent  development  consists  in  the  lateral 


A  section  of  the  Thymus  gland  at  the  eighth  month,  showing  its  anatomy ;  from  a  preparation  of  Sir  A. 
Cooper's :  1,  the  cervical  portions  of  the  gland  ;  the  independence  of  the  two  lateral  glands  is  well  marked  ; 
2,  secretory  follicles  seen  upon  the  surface  of  the  section ;  these  are  observed  in  all  parts  of  the  section ;  3,  3, 
the  pores  or  openings  of  the  secretory  follicles  and  pouches;  they  are  seen  covering  the  whole  internal  surface 
of  the  great  central  cavity  or  reservoir.  The  continuity  of  the  reservoir  in  the  lower  or  thoracic  portion  of  the 
gland  with  the  cervical  portion  is  seen  in  the  figure. 

growth  of  branching  offshoots  from  this  central  tubular  axis.  In  its  mature 
state,  therefore,  it  consists  of  an  assemblage  of  glandular  follicles,  which  are 
surrounded  by  a  plexus  of  bloodvessels;  and  these  follicles  all  communicate 
with  the  central  reservoir  from  which,  however,  there  is  no  outlet.  The  cavities 
of  the  follicles  contain  a  fluid,  in  which  a  number  of  corpuscles  are  found,  giving 
it  a  granular  appearance.  These  corpuscles,  the  diameter  of  which  varies  from 
l-5750th  to  l-2550th  of  an  inch,  usually  averaging  between  l-4000th  and 
l-5000th,  are  for  the  most  part  in  the  condition  of  nuclei;  but  fully-developed 
cells  are  found  among  them,  at  the  period  when  the  function  of  this  body  seems 
most  active.  The  chemical  nature  of  its  contents,  at  this  period,  closely  resem- 
bles that  of  the  ordinary  protein  compounds. — The  Vascular  supply  of  this 
organ,  during  the  period  of  its  functional  activity,  is  extremely  abundant ;  and 
the  capillary  network  into  which  the  arterial  branches  subdivide  closely  sur- 
rounds the  exterior  of  the  follicles,  arid  is  so  exceedingly  dense  that  its  meshes 
are  of  less  diameter  than  the  vessels  themselves.  The  Lymphatics  are  large, 
and  communicate  directly  with  the  Vena  Cava ;  but  their  immediate  connection 
with  the  cavity  of  the  Thymus  body  has  not  yet  been  demonstrated.  It  has 
been  commonly  stated,  that  the  Thymus  attains  its  greatest  development,  in 
relation  to  the  rest  of  the  body,  during  the  latter  part  of  foetal  life  ;  and  it  has 
been  considered  as  an  organ  peculiarly  connected  with  the  embryonic  condition. 
But  this  is  a  mistake ;  for  the  greatest  activity  in  the  growth  of  this  organ 
manifests  itself,  in  the  Human  infant,  soon  after  birth ;  and  it  is  then,  too,  that 
its  functional  energy  seems  the  greatest.  This  rapid  state  of  growth,  however, 


FUNCTIONS   OF   THE   DUCTLESS   GLANDS.  461 

soon  subsides  into  one  of  less  activity,  which  merely  serves  to  keep  up  its  pro- 
portion to  the  rest  of  the  body ;  and  its  increase  usually  ceases  altogether  at  the 
age  of  about  two  years.  From  that  time,  during  a  variable  number  of  years,  it 
remains  stationary  in  point  of  size ;  but,  if  the  individual  be  adequately  nour- 
ished, it  gradually  assumes  the  character  of  a  mass  of  fat,  by  the  development 
of  the  corpuscles  of  its  interior  into  fat-cells,  which  secrete  adipose  matter  from 
the  blood.  This  change  in  its  function  is  most  remarkable  in  hybernating 
Mammals ;  in  which  the  development  of  the  organ  continues,  even  in  an  in- 
creasing ratio,  until  the  animal  reaches  adult  age,  when  it  includes  a  large 
quantity  of  fatty  matter.  The  same  is  the  case,  generally  speaking,  among 
Reptiles.1 

487.  The   Thyroid  body  accords  rather  with  the  Supra-renal  capsules,  than 
with  the  Thyrnus,  in  its  elementary  structure;  for  it  consists  of  a  number  of 
isolated  vesicles,  which  do  not  communicate  with  any  common  reservoir.    These 
vary  in  diameter,  in  the  Human  subject,  from  l-2000th  to  l-85th  of  an  inch;  and 
they  contain  an  albuminoid  plasma,3  which  is  either  faintly  granular,  or  of  a 
somewhat  oily  aspect,  amidst  which  are  seen  a  number  of  corpuscles,   of  an 
average  diameter,  of  l-3000th  of  an  inch,  of  which  the  greater  part  are  in  the 
condition  of  nuclei,  whilst  some  have  advanced  to  that  of  cells.     These  corpus- 
cles seem  rather  to  occupy  the  position  of  an  epithelium  within  the  vesicles, 
than  to  float  freely  in  their  contained  fluid.     The  vascular  supply  of  the  Thyroid 
body  is  extremely  abundant ;  and,  as  in  the  preceding  instances,  the  subdivisions 
of  its  arteries  form  a  very  minute  capillary  plexus  upon  the  membrane  of  the 
vesicles.     The  Lymphatics  have  not  been  traced  far  into  its  substance. — The 
development  of  the  Thyroid  body  has  been  shown  by  Mr.  Gray  (loc.  cit.)  to 
be  closely  accordant  with  that  of  the  "  ductless  glands"  already  described.    This 
body  originates  in  two  separate  masses  of  blastema,  one  at  each  side  of  the  root 
of  the  neck,  close  to  the  separation  of  the  carotid  and  subclavian  vessels,  and 
between  the  trachea  and  the  branchial  clefts,  but  quite  independent,  as  far  as 
regards  their  development,  of  either  of  those  parts.     Their  minute  structure  at 
an  early  period  closely  corresponds  with  that  of  the  spleen  and  supra-renal 
glands ;  and  the  formation  of  their  vesicles  takes  place  after  precisely  the  same 
plan.     This  body,  like  the  Supra-renal  and  Thymus,  is  of  larger  relative  mag- 
nitude during  intra-uterine  existence  and  infancy  than  in  after  life. 

488.  That  the  Ductless  Glands,  of  whose  peculiar  structure  and  relations  we 
have  thus  taken  a  general  survey,  have  some  office  of  importance  to  perform  in 
the  preparation  and  maintenance  of  the  Blood,  cannot  any  longer  be  reasonably 
questioned ;  and  the  determination  of  this  point  may  be  fairly  regarded  as  a 
considerable  step  in  the  investigation.     It  is   obvious,  from  the  very  copious 
supply  of  blood  which  they  receive  during  the  period  of  their  functional  vigor, 
and  from  the  manner  in  which  this  is  distributed  by  minute  capillary  plexuses, 
on  the  exterior,  and  even  through  the  interior,  of  the  glandular  vesicles,  that 
it  must  be  subservient  to  some  process  of  active  change ;  and  the  aspect  of  the 
contents  of  these  vesicles,  as  well  as  of  the  substance  in  which  they  are  imbedded, 
indicates  that  cell-growth  is  rapidly  proceeding,  at  the  expense  of  the  materials 
thus  afforded.     But,  on  the  other  hand,  that  the  products  of  this  cell-growth 
are  not  substances  which,  like  those  of  the  ordinary  glands,  must  be  separated 
from  the  Blood,  either  for  its  purification,  or  to  serve  some  special  purpose  in  the 
economy,  appears  from  the  fact  that  they  are  not  carried  off  by  ducts,  but  are 
received  again  into  the  current  of  the  circulation.     This  would  be  equally  true 

1  See  Mr.  Simon's  admirable  "Physiological  Essay  on  the  Thymus  Gland,"  from  which 
the  foregoing  summary  has  been  derived. 

2  That  the  fluid  does  not  contain  true  Albumen  in  solution,  but  some  albuminous  com- 
pounds, is  indicated  by  the  results   of   Mr.  Beale's  analysis  ("Cyclop,   of  Anat.  and 
Physiol.,"  vol.  iv.  p.  1106). 


462  OF   ABSORPTION   AND    SANGUIFICATION. 

in  the  end,  were  these  products  discharged  (as  formerly  supposed)  by  the  Lymph- 
atics; but  such  an  idea  is  inconsistent  with  our  present  knowledge  of  the 
distribution  of  these  vessels ;  and  it  may  be  considered  next  to  certain  that  the 
matters,  whatever  their  nature  may  be,  which  have  been  elaborated  by  these 
glandular  organs,  are  received  again  through  the  capillaries  into  the  Venous 
system.  With  the  exception  of  the  Spleen,  all  the  ductless  glands  thus  dis- 
charge their  products  at  once  into  the  general  venous  circulation ;  so  that,  after 
having  passed  through  the  lungs,  they  will  be  carried  by  the  systemic  arteries 
through  the  system  at  large  :  but  the  splenic  vein,  it  will  be  remembered,  forms 
one  of  the  roots  of  the  portal  trunk,  and  its  blood  must  thus  pass  through  the 
liver,  before  it  enters  the  vena  cava.  For  this  exception,  a  reason  may  possi- 
bly be  found  in  one  of  the  offices  which  has  been  attributed  to  the  Spleen. 

489.  Whatever  materials,  then,  are  withdrawn  from  the  Blood  by  these  organs, 
are  returned  to  it  again  in  an  altered  state ;  and  that  the  change  which  they  have 
undergone  is  one  that  prepares  them  for  higher  uses  in  the  economy  may  fairly 
be  inferred  from  this  circumstance.  For,  as  the  blood  which  has  received  them 
is  immediately  transmitted  to  the  system  (except  in  the  case  of  the  splenic  blood) 
without  having  passed  through  any  other  depurating  organ  than  the  lungs,  it 
appears  fair  to  conclude  that  the  products  which  it  has  taken  up  in  these  organs 
are  either  combustive  or  nutritive,  i.  e.}  either  serve  to  maintain  the  functional 
activity  of  the  lungs,  or  of  the  system,  or  of  the  blood  itself.  Now  that  they 
are  not  destined  to  prepare  a  pabulum  for  respiration  appears  from  the  very 
small  quantity  of  fat  which  is  found  in  their  substance,  except  when  their  period 
of  functional  activity  has  gone  by.  On  the  other  hand,  the  albuminous  nature 
of  the  plasma,  and  the  finely-granular  appearance  which  it  presents,  strongly 
indicate  that  a  material  is  here  in  progress  of  preparation,  which  is  to  be  rendered 
subservient  to  the  formative  operations.  Various  facts  which  have  been  noticed 
in  regard  to  the  changes  in  the  bulk  of  the  Thymus  in  young  animals  (and  par- 
ticularly its  rapid  diminution  in  over-driven  lambs,  and  its  subsequent  gradual 
re-distension  during  rest  if  plentiful  nutriment  be  afforded),  lead  to  the  con- 
clusion that  such  is  almost  undoubtedly  the  function  of  that  body;  and 
the  close  resemblance  which  it  bears  to  the  rest  in  every  essential  particular, 
seems  to  justify  our  extension  of  this  inference  to  them. — But,  further,  it  does 
not  seem  at  all  unreasonable  to  suppose  that  these  organs  may  be  concerned, 
equally  with  the  Absorbent  glands,  in  supplying  the  germs  of  those  cells  which 
are  ultimately  to  become  Blood-corpuscles.  Such,  it  is  well  known,  was  the 
doctrine  of  Hewson1  in  regard  to  the  Spleen  and  Thymus  gland ;  and  there  are 
many  facts  which  lend  it  a  considerable  probability.  In  the  first  place,  that 
there  is  no  physical  impossibility  in  the  reception  of  particles  of  such  a  size  into 
the  interior  of  a  closed  system  of  capillaries,  is  proved  by  the  very  curious  facts 
already  noticed  in  regard  to  the  passage  of  starch-grains  into  the  mesenteric  veins 
(§  465).  Secondly,  many  observers  have  noticed  an  unusual  proportion  of  color- 
less corpuscles  in  the  blood  of  the  splenic  vein3  (§  491).  Thirdly,  the  period  of 
greatest  functional  activity  of  all  these  glands  is  during  the  state  of  early  child- 
hood, when  the  formative  processes  are  going  on  with  extraordinary  activity ; 
and  there  is  at  this  time  a  larger  proportion  of  colorless  corpuscles  in  the  blood, 
than  at  any  subsequent  period,  at  least  in  the  healthy  state.  Further,  as  Prof. 
J.  H.  Bennett  has  pointed  out,  the  peculiar  condition  of  the  blood,  which  consists 
in  the  multiplication  of  its  colorless  corpuscles  (§  175),  is  almost  always  asso- 
ciated with  hypertrophy  of  one  of  these  bodies;  and  in  one  case  of  this  kind,  in 
which  the  thyroid  was  the  organ  affected,  its  cells  and  their  included  nuclei  were 

1  See  his  Third  Series  of  "Experimental  Inquiries,"  Chaps,  iii. — v. 
a  For  one  of  the  most  recent  and  satisfactory  testimonies  to  this  fact,  see  Funke  in 
"Henle's  Zeitschrift,"  1851,  p.  172. 


FUNCTIONS   OF   THE   DUCTLESS   GLANDS.  463 

observed  to  be  considerably  smaller  than  usual,  and  the  same  peculiarity  pre- 
sented itself  in  the  colorless  corpuscles  of  the  blood.1  Hence  there  seems  a 
strong  probability,  that,  whilst  the  plasma  of  the  blood  is  being  elaborated  by 
these  bodies,  a  constant  supply  of  new  blood-corpuscles  is  also  afforded  by  them.2 
490.  The  peculiar  position  of  the  Spleen,  in  reference  to  the  Portal  circula- 
tion, however,  seems  to  mark  it  out  as  having  some  special  function  of  a  supple- 
mental character.  Two  out  of  the  many  theories  of  its  action  which  have  been 
advanced  deserve  particular  notice  in  connection  with  this  point.  Many  expe- 
rimenters have  come  to  the  conclusion,  that,  whatever  may  be  the  other  purposes 
answered  by  the  Spleen,  it  serves  as  a  diverticulum  to  the  Portal  circulation,  so 
as  to  relieve  its  vessels  from  undue  turgescence,  in  virtue  of  the  readiness  with 
which  it  is  distended  with  blood;  and  this  under  a  great  variety  of  circumstances. 
As  the  portal  system  is  destitute  of  valves,  the  splenic  vein  has  free  communi- 
cation with  the  whole  of  it;  so  that  the  Spleen  will  serve  as  a  receptacle  for  the 
venous  blood,  when  the  secreting  action  of  the  Liver  is  feeble,  so  that  the  portal 
circulation  receives  a  partial  check.  That  any  cause  of  obstruction  to  the  hepatic 
circulation  peculiarly  affects  the  Spleen,  has  been  proved  by  experiment;  for 
after  the  Vena  Portse  has  been  tied,  the  spleen  of  an  animal,  which  previously 
weighed  only  2  oz.,  has  been  found  to  weigh  a  pound  and  a  quarter,  or  ten  times 
as  much.  Further,  it  is  evident  that  turgescence  of  the  portal  system  is  liable 
to  occur,  when  the  alimentary  canal  is  distended  with  food ;  and  this  from  two 
causes — the  pressure  on  the  intestinal  veins,  and  the  quantity  of  fluid  absorbed 
by  these  veins.  Hence  it  may  be  conceived,  that  the  Spleen,  by  affording  a 
reservoir  into  which  the  superfluous  blood  may  be  directed,  serves  an  important 
purpose  in  preventing  congestion  of  other  organs.  From  the  observations  of 
Mr.  Dobson,3  it  appears  that  the  Spleen  has  its  maximum  volume  at  the  time 
when  the  process  of  chymification  is  at  an  end — namely,  about  five  hours  after 
food  is  taken;  and  that  it  is  small  and  contains  little  blood  seven  hours  later, 
when  no  food  has  been  taken  in  the  interval.  Hence  he  inferred  that  this  organ 
is  the  receptacle  for  the  increased  quantity  of  blood  which  the  system  acquires 
from  the  food,  and  which  cannot,  without  danger,  be  admitted  into  the  blood- 
vessels generally;  and  that  it  regains  its  previous  dimensions,  after  the  volume 
of  the  circulating  fluid  has  been  reduced  by  secretion.  This  view  is  confirmed 
by  the  fact  noticed  by  several  observers — that  the  Spleen  rapidly  increases  in 
bulk  after  the  ingestion  of  a  large  quantity  of  fluid,  which  is  absorbed  rather  by 
the  Veins  than  by  the  Lacteals.  It  has  been  further  stated  in  support  of  this 
theory,  that  animals  from  which  the  Spleen  has  been  removed,  are  very  liable 
to  die  of  apoplexy,  if  they  take  a  large  quantity  of  food  at  a  time;  but  that,  if 
they  eat  moderately  and  frequently,  they  do  not  suffer  in  this  manner. — Now 
this  doctrine  derives  its  chief  support  from  experiments  on  Ruminating  and  other 
Herbivorous  animals,  whose  food  is  very  bulky,  and  who  ingest  a  large  quantity 
of  it  at  a  time ;  and  it  is  in  them  that  the  organ  is  most  distensible,  and  that 
the  splenic  vein  is  best  adapted,  by  the  peculiar  disposition  of  its  coats,  for  the 
reception  of  a  very  large  amount  of  blood.  The  cellated  structure  which  forms 
a  large  part  of  the  spleen  in  these  tribes,  is  almost  wanting  in  Man ;  and  the 
fibrous  envelop  of  his  spleen,  with  its  trabecular  partitions,  has  very  little  either 
of  elasticity  or  contractility.  Nevertheless,  there  is  evidence  that  an  extraordi- 
nary accumulation  of  blood  may  take  place  in  this  organ  even  in  him,  from  any 

1  This  fact  is  the  more  weighty,  as,  in  another  case  observed  by  Prof.  Bennett,  the  color- 
less corpuscles  of  the  blood  were  of  two  distinct  sizes,  the  smaller  corresponding  with  the 
nuclei  of  the  larger  ones ;  and  the  lymphatic  glands  were  found  to  be  crowded  with  corpus- 
cles also  of  two  distinct  sizes,  exactly  corresponding  with  those  of  the  blood.    (See  "Edinb. 
Monthly  Journal,"  October,  1851.) 

2  This  view  has  been  ably  supported  by  Prof.  J.  H.  Bennett,  in  "Edinb.  Monthly  Journ.," 
March,  1852. 

3  "  London  Med.  and  Phys.  Journ.,"  Oct.,  1820. 


464  OF   ABSORPTION    AND    SANGUIFICATION. 

cause  which  obstructs  the  passage  of  blood  through  the  liver,  or  which  impedes 
its  return  to  the  heart  (as  in  Asphyxia,  §  574),  or  which  occasions  a  general 
internal  venous  congestion,  such  as  occurs  in  the  cold  stage  of  intermittent  fever. 
The  peculiar  liability  of  the  Spleen  to  be  distended  with  blood  in  this  last  con- 
dition, is  shown  by  its  permanent  enlargement  in  those  who  have  been  long  the 
subjects  of  such  complaints. — Thus  it  appears  that  the  Spleen  may  serve,  inde- 
pendently of  its  primary  function,  as  a  sort  of  safety-valve  to  the  portal  circula- 
tion ;  and  that  its  structure  is  most  particularly  adapted  for  such  a  purpose  in 
those  tribes  of  animals  which,  from  their  habits  of  feeding,  may  be  considered 
most  specially  to  need  an  organization  of  this  kind. 

491.  It  is  further  maintained  by  Prof.  Kolliker,  that  one  function,  at  least, 
of  the  Spleen,  is  to  dissolve  the  effete  Red  Corpuscles  of  the  blood,  and  to  prepare 
their  Hsematine  for  becoming  the  coloring  matter  of  the  Bile.  This  view  is 
grounded  upon  the  existence  of  the  peculiar  aggregations  of  cells  resembling  red 
corpuscles  in  a  state  of  disintegration,  of  which  mention  has  already  been  made 
(§  482,  IV.) ;  and  it  seems  to  derive  confirmation  from  the  results  of  Beclard's 
analyses  of  the  blood  of  the  Splenic  vein,  which  show  a  marked  deficiency  in  the 
amount  of  red  corpuscles,  and  an  excess  of  the  albuminous  constituent,  as  com- 
pared with  the  blood  of  other  parts  (§  168).  It  must  be  remembered,  however, 
that  such  aggregations  are  by  no  means  peculiar  to  -the  Spleen,  but  have  been 
found  in  the  substance  of  Muscles,  Glands,  and  other  organs ;  and  although  the 
peculiar  conditions  of  the  circulation  in  the  Spleen  may  tend  to  produce  them 
in  unusual  numbers,  their  formation  can  scarcely  be  regarded  as  one  of  the 
essential  functions  of  the  organ.1 

[A  most  able  microscopical  and  chemical  examination  of  the  blood  of  the 
splenic  vein  has  been  made  by  Dr.  OTTO  FUNKE.  The  original  paper  published 
in  "Henle's  Zeitschrift/'  1851,  p.  172,  is  a  very  long  one,  and  we  have  selected 
only  some  portions  of  it.  Funke,  for  various  reasons,  chose  the  blood  of  horses 
for  his  investigation. 

Under  the  microscope,  the  splenic  venous  blood  presented  remarkable  differ- 
ences from  the  blood  of  the  general  venous  system,  as  represented  by  the  blood 
of  the  jugular  vein,  and  from  arterial  blood.  The  red  corpuscles  did  not  form 
rouleaux,  but  in  great  numbers  were  aggregated  in  thick,  irregular  heaps,  or  in 
smaller  numbers  (6  to  12)  forming  little  round  or  angular  flakes,  such  as  Ecker 
describes  in  the  spleen-pulp.  Pressure  did  not  separate  these  heaps,  but  merely 
produced  chasms  at  certain  points.  After  some  days,  this  firm  cohesion  of  the 
corpuscles  diminished.  The  size  of  the  corpuscles  varied  extremely,  but  the 
majority  were  very  small — smaller,  indeed,  than  the  corpuscles  found  elsewhere. 
The  white  corpuscles  were  excessively  numerous ;  in  one  case  they  amounted 
in  number  to  a  quarter  or  a  third  part  of  the  colored  particles ;  they  collected 
also  in  heaps,  and  seemed  to  be  united  by  a  fine  molecular  matter.  In  some 
places  they  were  mixed  up  with  the  red  particles.  In  size  they  varied  greatly, 
being  sometimes  as  large  as  a  red  particle,  at  other  times  double  the  size.  Some 
clearly  contained  a  single  nucleus.  Although  not  absolutely  certain  of  the 
fact,  Funke  believes  that  he  traced  the  transition  forms  from  one  set  of  particles 
into  the  other. 

Besides  these  cells  there  were  constantly  present  "granular  cells"  (Kornchen- 
zellen),  so  to  call  them,  although  Funke  does  not  desire  to  imply  that  they  are 
the  same  as  the  various  cell-forms  often  placed  under  this  title.  They  were 
larger  than  the  colorless  corpuscles,  and  lay  among  them  aggregated,  or  in  heaps 
of  two  or  three  together.  They  were  undoubtedly  cells,  and  the  cell  wall 
could  be  plainly  seen ;  they  were  always  spherical,  transparent,  with  a  defined 
border,  and  contained  from  four  to  ten  small,  dark,  outlined,  strongly  refracting 

1  See  Prof.  J.  H.  Bennett  in  "Edinb.  Monthly  Journal,"  March,  1852,  p.  211. 


FUNCTIONS   OF   THE   DUCTLESS   GLANDS.  465 

granules,  grouped  in  various  ways,  either  centrally  heaped  together,  or  forming 
a  crescent,  or  without  particular  order,  and  frequently  changing  their  mode 
of  arrangement.  Generally  colorless,  these  cells  were  sometimes  slightly  yellow; 
they  appeared  to  be  identical  with  cells  described  by  Ecker  in  the  spleen-pulp. 

Pigment  cells,  as  described  by  Ecker  and  Kb'lliker,  were  never  seen. 

Once  only,  in  many  hundred  examinations,  could  Funke  find  a  blood-corpus- 
cle-holding cells,  although  he  examined  more  than  a  hundred  drops  of  blood. 
As  he  could  often  find  the  cells  in  the  spleen,  he  suggests  two  possible  reasons 
for  their  rare  appearance  in  the  splenic  venous  blood ;  either  they  had  become 
destroyed  during  the  considerable  space  of  time  after  death  which  elapsed  be- 
fore he  examined  the  blood,  or  they  are  really  absent  in  the  blood  issuing  from 
the  spleen.  Funke  does  not  attach  much  importance  to  the  first  suggestion,  as, 
in  the  venous  splenic  blood  of  a  dog  examined  at  once  after  death,  he  could  find 
none  of  these  cells.  He  is  inclined  to  adopt  the  view  that  the  blood-corpuscles 
are  destroyed  in  the  spleen.  The  single  cell  seen  by  him  in  the  venous  blood 
was  tolerably  large,  oblong,  transparent,  with  an  evident  granular  nucleus,  and 
in  its  centre  were  three  unchanged  blood-corpuscles,  similar  to  those  external  to 
the  cell. 

There  were  also  in  the  splenic-venous  blood  of  the  horse  some  singular,  or,  as 
Funke  terms  them,  "enigmatical  bodies,"  about  whose  nature  he  seems  very 
doubtful.  These  were  round  or  oblong  bodies,  with  defined  outlines,  slightly 
granular  on  the  surface,  of  various  sizes,  sometimes  as  large  as  a  starch  granule, 
at  other  times  almost  filling  the  field  of  view  ;  they  lay  in  the  spaces  between 
the  heaps  of  red  corpuscles,  or  were  sometimes  enclosed  round  by  these  or  by 
white  corpuscles,  like  a  ring.  Whether  they  are  cells  or  amorphous  heaps, 
Funke  does  not  know,  but  inclines  to  the  former  opinion.  He  found  them  not 
only  in  the  horse,  but  in  the  fresh  blood  of  the  dog. 

Besides  these  forms  there  were  fibrinous  flakes. 

The  addition  of  weak  acetic  acid  produced  the  following  changes.  Some  red 
corpuscles  were  entirely  destroyed;  others  smaller  and  less  deep-colored  were 
not  affected,  as  Gerlach  has  also  noticed — the  white  corpuscles  were  made  quite 
hyaline,  but  the  outer  wall  was  not  destroyed  for  a  long  time ;  the  nuclei  were 
brought  clearly  into  view,  were  spheres  or  ellipses,  eccentric,  faintly  spotted, 
and  usually  single,  or  less  commonly  double  or  treble.  The  granular  cells 
were  made  hyaline,  and  dissolved  slowly;  the  granules  appeared  at  first  to 
Funke  to  be  unaffected,  but  more  accurate  observations  taught  him  that  they 
also  dissolved ;  and,  therefore,  in  spite  of  their  remarkable  resemblance,  they 
were  not  fat.  The  peculiar  round  enigmatical  bodies  were  unaffected  by  the 
acid. 

The  effect  of  water  on  the  splenic  venous  blood  was  most  remarkable.  If  a 
drop  of  blood  is  placed  on  the  object-glass,  and  allowed  somewhat  to  dry,  and 
then  if  water  is  added,  the  following  changes  occur — for  some  time  the  blood- 
corpuscles  diminish,  become  indented,  then  oblong  and  linear,  and  at  last  take 
the  form  of  little  rods,  so  to  call  them ;  these  extend  in  length  and  form  at  length 
prismatic  needle-like  crystals  crossing  the  field  in  all  directions,  and  interlacing. 
This  process  is  so  rapid  that  it  is  difficult  to  observe  that  these  crystals  really 
form  out  of  the  blood-corpuscles.  ("  Aus  den  Blutkorperchen  selbst  Entstehen.") 
These  crystals  were  red  colored ;  their  exact  crystalline  form  could  not  be  accu- 
rately determined ;  but  they  appeared,  in  some  cases,  certainly  to  be  six-sided 
prisms,  with  dihedral  apices.  Besides  these  crystals,  there  was  another  form, 
consisting  of  rhombic  tables,  like  cholesterine,  and  of  various  sizes.  Many  of 
the  blood-corpuscles  remained  unchanged. 

The  needle-form  and  prismatic  crystals  sometimes  appeared,  though  in  im- 
perfect forms,  by  simple  drying  of  the  splenic  blood,  without  the  addition  of  any 
30 


466  OF   THE   CIRCULATION   OP   THE   BLOOD. 

water.  With  respect  to  the  chemical  nature  of  these  crystals,  and  to  the  effect 
of  reagents  upon  them,  Funke  has  made  innumerable  experiments,  but  without 
being  able  to  come  to  any  positive  results.1 — ED.] 


CHAPTER  IX. 

OF   THE   CIRCULATION   OF   THE   BLOOD. 

1. —  Of  the  Circulation  in  General. 

492.  THE  Circulation  of  nutritive  fluid  through  the  body  has  for  its  object, 
on  the  one  part,  to  convey  to  every  portion  of  the  organism  the  materials  for  its 
growth  and  renovation,  together  with  the  supply  of  Oxygen  which  is  requisite 
for  its  vital  actions,  especially  those  of  the  Nervo-Muscular  apparatus ;  and  at 
the  same  time  to  carry  off  the  particles  which  are  set  free  by  the  disintegration 
or  "  waste"  of  the  tissues,  and  which  are  to  be  removed  from  the  body  by  the 
Excreting  processes.     Of  these  processes,  the  one  most  constantly  in  operation, 
as  well  as  most  necessary  for  the  maintenance  of  the  purity  of  the  blood,  is  the 
extrication  of  Carbonic  acid,  through  the  Respiratory  organs ;  and  this  is  made 
subservient  to  the  introduction  of  Oxygen  into  the  system.     In  Man,  as  in  other 
Vertebrated  animals,  there  is  a  regular  and  continuous  movement  of  the  nutri- 
tive fluid  through  the  sanguiferous  vessels  ;  and  upon  the  maintenance  of  this, 
the  activity  of  all  parts  of  the  organism  is  dependent.     In  common  with  Birds 
and  Mammals,  again,  Man  has  a  Respiratory  circulation  entirely  distinct  from 
the  Systemic;  all  the  blood  which  has  returned  from  the  body  being  transmitted 
to  the  lungs,  and  being  brought  back  to  the  heart  again,  before  it  is  again  sent 
forth  for  the  nourishment  of  the  tissues  and  for  the  maintenance  of  their  func- 
tional activity.     The  heart  is  placed  at  the  junction  of  these  two  distinct  circu- 
lations, which  may  be  likened  to  the  figure  8 ;  and  it  may  be  said  to  be  formed  by 
the  fusion  of  two  distinct  organs,  a  "pulmonary"  and  a  " systemic"  heart;  for 
its  right  and  left  sides,  which  are  respectively  appropriated  to  these  purposes, 
have  no  direct  communication  with  each  other  (in  the  perfect  adult  condition,  at 
least),  and  seem  merely  brought  together  for  economy  of  material.3     Each  system 
has  its  own  set  of  Arteries  or  efferent  vessels,  and  of  Veins  or  afferent  trunks ; 
these  communicate  at  their  central  extremity  by  the  Heart,  and  at  their  peri- 
pheral extremity  by  the  Capillary  vessels,  which   are  nothing  else  than  the 
minutest  ramifications  of  the  two  systems  inosculating  into  a  plexus  (§  292). — 
Besides  the  systemic  and  pulmonary  circulations,  however,  there  is   another 
which  is  no  less  distinct,  although  it  has  not  an  impelling  organ  of  its  own. 
This  is  the  "  portal"  circulation,  which  is  interposed  between  the  venous  trunks 
of  the  abdominal  viscera  and  the  Vena  Cava,  for  the  purpose  of  distributing  that 
blood  through  the  Liver,  in  which  organ  its  newly-absorbed  materials  undergo 
assimilation  (§  472),  whilst  its  excrementitious  matters  are  separated  by  the 
secreting  process.     The  Vena  Portse,  which  is  formed  by  the  convergence  of  the 
gastric,  intestinal,  splenic,  and  pancreatic  veins,  subdivides  again  like  an  artery, 
so  as  to  form  a  capillary  plexus  which  extends  through  the  whole  substance  of 

1  American  Journal  of  Med.  Sciences,  April,  1852. 

2  At  an  early  period  of  foetal  life,  as  in  the  permanent  state  of  the  Dugong,  the  heart  is 
so  deeply  cleft,  from  the  apex  towards  the  base,  as  almost  to  give  the  idea  of  two  separate 
organs. 


THE    CIRCULATION   IN   GENERAL.  467 

the  liver;  and  the  Hepatic  vein,  collecting  the  blood  from  this  plexus,  conveys 
it  into  the  Vena  Cava.  Thus  the  portal  circulation  is  grafted  (so  to  speak)  upon 
the  general  circulation,  in  precisely  the  same  mode  as  the  respiratory  circulation 
is  grafted  upon  it  in  Mollusca  and  Crustacea ;  and  if  the* il  sinus"  of  the  vena 
portse  had  possessed  contractile  muscular  walls,  it  would  have  ranked  as  the 
proper  heart  of  the  portal  system.  The  really  arterial  character  of  the  Vena 
portae  is  well  shown  by  comparing  it  with  the  Aorta  of  Fishes ;  which  is  formed 
by  the  convergence  of  the  branchial  veins,  and  then  distributes  the  blood  which 
it  has  received  from  them  to  the  body  generally.1 

493.  That  the  movement  of  the  Blood  through  the  arterial  trunks  and  the 
capillary  tubes,  is,  in  Man,  and  in  other  warm-blooded  animals,  chiefly  depend- 
ent upon  the  action  of  the  Heart,  there  can  be  no  doubt  whatever.  It  can  be 
easily  shown  by  experiment,  that  if  the  arterial  current  be  checked,  the  capil- 
laries will  immediately  cease  almost  entirely  to  deliver  the  blood  into  the  veins, 
and  the  venous  circulation  will  be  instantaneously  arrested.  And  it  has  also 
been  proved,  that  the  usual  force  of  the  Heart  is  sufficient  to  propel  the  blood, 
not  only  through  the  arterial  tubes,  but  through  the  capillaries,  into  the  veins; 
since  even  a  less  force  will  serve  to  propel  warm  water  through  the  vessels  of  an 
animal  recently  dead.3  But  there  are  certain  "  residual  phenomena"  even  in 
Man,  which  clearly  indicate  that  this  is  not  the  whole  truth;  and  that  forces 
existing  in  the  Bloodvessels  themselves  have  a  considerable  influence,  in  pro- 
ducing both  local  and  general  modifications  of  the  effects  of  the  Heart's  action. 
There  are  also  indications  of  the  existence  of  an  influence  in  which  the  blood- 
vessels do  not  partake,  arising  from  those  changes  occurring  between  the  blood 
and  the  tissues,  that  constitute  the  process  of  Nutrition,  Secretion,  &c.  Such, 
for  instance,  would  appear  to  be  the  interpretation  of  the  fact,  that  whilst  any 
variations  in  the  action  of  the  Heart  affect  the  whole  system  alike,  there  are 
many  variations  in  the  Circulation,  which,  being  very  limited  in  their  extent, 
cannot  be  attributed  to  such  central  disturbances,  and  must  therefore  be  depend- 
ent on  causes  purely  local. — Of  the  nature  of  these  influences,  and  of  the  mode 
of  their  operation,  the  most  correct  idea  may  be  obtained  by  examining  the 
phenomena  of  the  Circulation  in  those  beings,  in  which  the  moving  power  is 
less  concentrated  than  it  is  in  the  higher  Animals;  for  we  find  that  in  Plants 
and  the  lowest  Animals,  as  in  the  earliest  embryonic  state  of  the  highest,  a 
movement  of  nutritious  fluid  takes  place  through  a  system  of  minute  passages 
or  channels  excavated  in  the  tissue  (representing  a  capillary  plexus),  without 
any  vis  a  tergo  derived  from  an  impelling  organ.  Ascending  a  little  higher  in 
the  series,  we  meet  with  a  system  of  vascular  trunks,  distributing  the  blood  to 
these  plexuses,  and  collecting  it  again  from  them ;  and  the  walls  of  these  trunks 
are  so  far  endowed  with  contractility,  as  to  assist,  by  a  sort  of  peristaltic  move- 
ment, in  the  maintenance  of  the  current  through  them.  Still  passing  upwards, 
we  find  this  contractility  manifesting  itself  especially  in  some  limited  portion  or 
portions  of  the  vascular  system,  which  execute  regular  movements  of  contrac- 
tion and  dilatation;  and  this  tendency  to  concentration  is  observed  to  increase, 
until  the  whole  movement  is  subordinated  to  the  action  of  a  principal  propelling 
organ,  the  Heart.3  We  shall  now  examine  what  agency  in  the  Human  Circu- 
lation may  be  attributed  to  the  Heart,  the  Arteries,  and  the  Veins  respectively ; 
and  what  other  forces  may  be  fairly  presumed  to  operate  in  the  Capillary  circu- 
lation. 

1  For  an  account  of  the  principal  modifications  of  tjie  Circulating  apparatus  in  the 
Animal  Kingdom,  see  "Princ.  of  Phys.,  Gen.  and  Comp.,"  pp.  677-710,  Am.  Ed. 

2  See  Dr.  Williams's  "Principles  of  Medicine,"  3d  Am.  Ed.,  p.  154,  note. 

3  See  the  Author's  "  Princ.  of  Phys.,  Gen.  and  Comp.,"  CHAP,  xn.,  Am.  Ed. 


OF    THE    CIRCULATION    OF   THE   BLOOD. 


2. — Action  of  the  Heart. 

494.  The  Heart  is  endowed  in  an  eminent  degree  with  the  property  of  irrita- 
bility; by  which  is  meant,  the  capability  of  being  easily  excited  to  movements 
of  contraction  alternating  with  relaxation  (§  315).     Thus,  after  the  Heart  has 
been  removed  from  the  body,  and  has  ceased  to  contract,  a  slight  irritation  will 
cause  it  to  execute,  not  one  movement  only,  but  a  series  of  alternate  contrac- 
tions and  dilatations,  gradually  diminishing  in  vigor  until  they  cease.     The  con- 
traction begins  in  the  part  irritated,  and  then  extends  to  the  rest.     It  appears 
from  Mr.  Paget's  experiments,1  that  it  is  necessary  for  the  propagation  of  this 
irritation,  that  the  parts  should  be  connected  by  muscular  tissue,  of  which  a  very 
narrow  isthmus  will  suffice;  and  that  the  propagation  will  not  take  place,  if  the 
connecting  isthmus  be  composed  of  tendon,  even  though  this  be  a  portion  of  the 
auriculo-ventricular  ring,  which  has  been  supposed  by  some  to  be  peculiarly  effi- 
cacious in  this  conduction. — -That  the  irritability  of  the  Heart  is  not  dependent 
upon  the  Cerebro-spinal  system,  appears  not  merely  from  the  manifestation  of  it 
when  the  organ  is  altogether  removed  from  the  body;  but  also  from  the  fact, 
that  if  the  flow  of  blood  through  the  lungs  be  kept  up  by  artificial  respiration, 
the  heart's  action  will  continue  for  a  lengthened  period,  even  after  the  Brain 
and  Spinal  Cord  have  been  removed,  and  when  animal  life  is,  therefore,  com- 
pletely extinct.     Hence  we  see  that  the  Irritability  of  this  organ  must  be  an 
endowment  properly  belonging  to  itself,  and  not  derived  from  that  portion  of  the 
Nervous  System.3     Like  the  contractility  of  other  muscles,  it  can  only  be  sus- 
tained for  any  great  length  of  time,  by  a  supply  of  Arterial  blood  to  its  own 
tissue  (§§  323,  324).  It  is  much  less  speedily  lost  in  cold-blooded  animals,  how- 
ever, than  in  warm-blooded;  the  heart  of  the  Frog,  for  example,  will  go  on 
pulsating  for  many  hours  after  its  removal  from  the  body;  and  it  is  stated  by 
l)r.  Mitchell3  that  the  heart  of  a  Sturgeon,  which  he  had  inflated  with  air,  con- 
tinued to  beat,  until  the  auricle  had  absolutely  become  so  dry,  as  to  rustle  dur- 
ing its  movements.     It  has  further  been  shown  by  Mr.  Tod,  that  the  irritability 
of  the  heart  is  of  long  duration  after  death  in  very  young  animals :  which,  as 
long  since  demonstrated  by  Dr.  Edwards,  agree  with  the  cold-blooded  Vertebrata 
in  their  power  of  sustaining  life,  for  a  lengthened  period,  without  oxygen. 

495.  It  is  difficult  to  account  for  the  long  continuance  of  the  alternate  con- 
tractions and  relaxations  of  the  muscular  parietes  of  the  Heart,  after  all  evident 
stimuli  have  ceased  to  act  upon  it ;  and  many  theories  have  been  offered  on  the 
subject,  none  of  which  afford  an  adequate  explanation.     The  extraordinary 
tendency  to  rhythmical  action,  which  distinguishes  the  heart  from  nearly  all 
other  muscles  (§  318,  note),  is  shown  by  the  fact,  that  not  only  do  the  entire 
hearts  of  cold-blooded  animals  continue  to  act,  long  after  their  removal  from 
the  body,  but  even  separated  portions  of  them  will  contract  and  relax  with  great 
regularity  for  a  long  time.     Thus  the  auricles  will  persist  in  their  rhythmical 
action,  when  cut  off  above  the  auriculo-ventricular  rings;  and  the  apex  of  the 

1  "Brit,  and  For.  Med.  Review,"  vol.  xxi.  p.  551. 

2  It  was  formerly  supposed,  that  the  movements  of  the  Heart  were  dependent  upon  its 
connection  with  the  centres  of  the  Cerebro-Spinal  nervous  system ;  and  the  experiments 
of  Legallois  and  others,  who  found  that  they  were  arrested  by  crushing,  or  otherwise  sud- 
denly destroying,  large  portions  of  these  centres,  appeared  to  favor  the  supposition.     But 
it  has  been  shown  by  Dr.  Wilson  Philip  and  his  successors  in  the  same  inquiry,  that  the 
whole  Cerebro-Spinal  axis  might  be  gradually  removed,  without  any  such  consequence ; 
which  fact  harmonizes  perfectly  with  the  "experiments  prepared  for  us  by  Nature,"  in 
the  production  of  monsters  destitute  of  these  centres,  which  nevertheless  possessed  a 
regularly-pulsating  heart. 

3  "American  Journal  of  the  Medical  Sciences,"  vol.  vii.  p.  58;  see  also  Prof.  Dungli- 
son's  "Human  Physiology,"  7th  edit.,  vol.  ii.  p.  149. 


ACTION   OF   THE   HEART. 

heart  will  do  the  same,  when  separated  from  the  rest  of  the  ventricle.  The 
stimulus  of  the  contact  of  the  blood  with  the  lining  membrane  of  the  heart,  to 
which  its  regular  actions  have  been  commonly  referred,  can  have  no  influence  in 
producing  such  movements ;  nor  does  it  appear  that  the  contact  of  air  can  take 
its  place ;  since,  as  Dr.  J.  Reid  has  shown,  the  rhythmical  contractions  of  the 
heart  of  a  frog  will  continue  in  vacua.1  Nor  is  there  any  evidence  that  the  flow 
of  blood  through  the  cavities  has  the  effect  of  securing  the  regularity  of  their 
successive  contractions  in  the  living  body;  for  this  regularity  is  equally  marked 
in  the  contractions  of  the  excised  heart,  when  perfectly  emptied  of  blood,  so 
long  as  its  movements  continue  vigorous.  But  when  its  irritability  is  nearly 
exhausted,  the  usual  rhythm  is  often  a  good  deal  disturbed,  so  that  the  contrac- 
tions of  the  auricles  and  ventricles  do  not  regularly  alternate  with  each  other ; 
and  one  set  frequently  ceases  before  the  other.  The  difficulty  of  finding  any 
other  satisfactory  solution  of  the  problem  has  recently  led  many  Physiologists 
to  recur  to  the  idea  that  the  Heart's  action  is  dependent  upon  Nervous  power; 
this  power  being  supposed  to  be  derived,  however,  not  from  the  Cerebro-spinal 
system,  but  from  the  ganglia  of  the  Sympathetic  system  which  are  found  in  the 
organ  itself.  For  the  proper  estimation  of  the  evidence  favorable  to  this  view, 
it  is  requisite  that  we  should  bring  together  the  principal  facts  which  indicate 
the  relation  of  the  Heart's  action  to  Nervous  influence,  from  whatever  source 
this  proceeds. 

496.  It  has  been  asserted  by  Valentin  and  other  experimenters,  that  mechani- 
cal irritation  of  the  Pneumogastric  nerves,  especially  at  their  roots,  has  a  tend- 
ency to  excite  or  accelerate  the  heart's  action;  numerous  experimenters,  how- 
ever, have  obtained  none  but  negative  results.  Admitting,  what  seems  probable, 
that  the  Cardiac  branches  of  the  Pneumogastric  have  some  influence  upon  the 
Heart's  action,  it  remains  to  inquire  whether  that  influence  be  essential  to  its 
movements ;  and  whether  these  nerves  form  the  channel  through  which  they  are 
affected  by  emotions  of  the  mind,  or  by  conditions  of  the  bodily  system.  In 
regard  to  the  first  point,  no  doubt  can  be  entertained;  since  the  regular  move- 
ments of  the  heart  are  but  little  affected  by  section  of  the  Pneumogastrics. 
With  respect  to  the  second,  there  is  more  difficulty ;  since  the  number  of  causes 
which  may  influence  the  rapidity  and  pulsations  of  the  heart  is  very  considera- 
ble. For  example,  when  the  blood  is  forced  on  more  rapidly  towards  the  heart, 
as  in  exercise,  struggling,  &c.,  its  contractions  are  rendered  more  frequent;  and 
when  the  current  moves  on  more  slowly,  as  in  a  state  of  rest,  their  frequency 
becomes  proportionably  diminished.  If  the  contractions  of  the  heart  were  not 
thus  in  some  degree  dependent  upon  the  blood,  and  their  number  were  not  regu- 
lated by  the  quantity  flowing  into  its  cavities,  very  serious  and  inevitably  fatal 
disturbances  of  the  heart's  action  would  soon  result.  That  this  adjustment  takes 
place  otherwise  than  through  the  medium  of  the  nervous  centres,  is  evident  from 
the  fact,  that,  in  a  dog,  in  which  the  Pneumogastric  and  Sympathetic  had  been 
divided  in  the  neck  on  each  side,  violent  struggling,  induced  by  alarm,  raised 
the  number  of  pulsations  from  130  to  260  per  minute.3  It  is  difficult  to  ascer- 
tain, by  experiments  upon  the  lower  animals,  whether  simple  emotion,  unat- 
tended with  struggling  or  other  exertion,  would  affect  the  pulsation  of  the  heart, 

1  "  Cyclopaedia  of  Anatomy  and  Physiology,"  vol.  ii.  p.  611. — This  experiment  has  been 
since  repeated  by  Prof.  Tiedemann  ("Muller's  Archiv.,"  1847)  and  by  Drs.  Mitchell  and 
Bache  (Prof.  Dunglison's  "  Human  Physiology,"  vol.  ii.  p.  150)  with  a  different  result;  the 
pulsations  being  speedily  brought  to  a  stand  by  the  exhaustion  of  the  air,  and  being  renewed 
when  it  was  re-admitted.     This,  however,  does  not  invalidate  the  positive  fact  that  the 
pulsation  may  continue  in  vacuo,  which  proves  that  the  stimulus  of  air  cannot  be  its  main- 
taining power  ;  and  only  shows  that  the  presence  of  oxygen  is  essential  to  the  continuance 
of  the  heart's  movements,  as  to  muscular  action  in  general  (§  324). 

2  See  Dr.  J.  Keid's  "  Anat.  Phys.  and  Path.  Researches,"  p.  170. 


470  OF   THE   CIRCULATION   OP   THE   BLOOD. 

after  section  of  the  Pneumogastrics;  but  when  the  large  proportion  of  the  Sym- 
pathetic nerves  proceeding  to  this  organ  is  considered,  and  when  it  is  also  re- 
membered that  irritation  of  the  roots  of  the  upper  cervical  nerves  stimulates 
the  action  of  the  heart  through  these,  we  can  scarcely  doubt  that  both  may 
serve  as  the  channels  of  this  influence,  especially  in  such  animals  as  the  dog,  in 
which  the  two  freely  inosculate  in  the  neck. — Although  there  is  a  difficulty  in 
proving  that  the  Heart's  action  can  be  excited  or  accelerated  by  irritation  of 
the  Pneumogastrics,  yet  these  nerves  may  serve  as  the  channel  of  an  influence 
of  a  very  opposite  character;  for  the  experiments  of  MM.  Weber  have  shown 
that  its  movements  may  be  immediately  arrested  by  the  transmission  of  the 
electric  current  from  a  rotating  magnet,  either  through  the  Spinal  Cord,  or 
through  the  Pneumogastrics  divided  at  their  origin ;  the  same  irritation,  how- 
ever, applied  to  a  single  one  of  the  Vagi,  produced  no  effect.1  Hence  it  is  ob- 
vious that  the  influence  of  sudden  and  violent  injury  to  the  Cerebro-spinal  centres, 
which  induces  an  immediate  diminution  or  suspension  of  the  Heart's  mechanical 
movements,  or  even  entirely  annihilates  them,  may  be  conveyed  through  these 
trunks,  as  well  as  through  the  Sympathetic  system  (§  321). 

497.  In  like  manner  it  may  be  shown  that  the  Heart's  action  may  be  affected 
by  influences  transmitted  through  the  Sympathetic  system  of  nerves.  There  is 
considerable  difficulty  in  obtaining  direct  experimental  evidence  to  this  effect,  of 
a  satisfactory  character ;  but  there  is  strong  reason  to  believe  that  the  effects  of 
shock  may  be  exerted  no  less  directly  through  the  Sympathetic  than  through 
the  Cerebro-spinal  system  (§  321);  and  that  considerable  disturbance  may  ensue 
from  lesions  of  such  parts  of  it  (at  least)  as  are  most  nearly  connected  with  the 
heart.  Thus  a  case  has  been  put  on  record,  in  which  the  heart's  pulsations  were 
occasionally  checked  for  an  interval  of  from  4  to  6  beats,  its  cessation  of  action 
giving  rise  to  the  most  fearful  sensations  of  anxiety,  and  to  acute  pain  passing 
up  to  the  head  from  both  sides  of  the  chest — these  symptoms  being  connected, 
as  it  proved  on  a  post-mortem  examination,  with  the  pressure  of  an  enlarged 
bronchial  gland  upon  the  great  cardiac  nerve.2  It  is  not  less  obvious,  however, 
in  regard  to  the  principal  centres  of  the  Sympathetic  system,  than  with  respect 
to  those  of  the  Cerebro-spinal,  that  in  whatever  degree  the  heart's  action  may  be 
influenced  through  them,  it  cannot  be  dependent  upon  any  power  which  it  derives 
from  them,  since  it  continues  after  the  complete  isolation  of  the  organ.  And 
the  very  difficulty  of  obtaining  experimental  evidence  of  this  influence,  notwith- 
standing the  extraordinary  irritability  of  the  Heart,  seems  to  show  that  the 
ordinary  movements  of  the  organ  are  but  little  dependent  upon  nervous  influence 
of  any  kind. — The  only  centres  of  nervous  power,  to  which,  consistently  with 
the  foregoing  facts,  the  maintenance  of  the  Heart's  action  can  be  attributed,  are 
the  numerous  ganglia,  forming  part  of  the  Sympathetic  system,  which  are  dis- 
persed through  its  substance,  but  which  are  brought  into  connection  with  each 
other  by  communicating  fibres.  These,  it  has  been  surmised,  may  act  as  centres 
of  " reflex"  action;  and  may  thus  keep  up  the  contractions  of  the  heart,  after 
its  complete  withdrawal  from  the  influence  of  the  Cerebro-spinal  and  of  the  princi- 
pal Sympathetic  centres,  just  as  the  ganglia  contained  in  the  separated  segments 
of  the  body  of  a  Centipede  are  centres  of  movement  to  the  limbs  with  which 
they  remain  in  connection.  But  this  hypothesis  does  not  give  any  real  solution 
to  the  difficulty;  for  in  every  case  of  true  "reflex"  action,  the  movement  is  ex- 
cited by  a  stimulus;  and  no  rhythmical  succession  of  movements  can  be  thus 

1  "Archives  d'Anat.  Gener.  et  de  Physiol.,"  Jan.,  1846;  and  "Wagner's  Handworter- 
buch,"  Art.  "Muskelbewegung." 

8  "MullerYArchiv.,"  1841,  heft  iii.  ;  and  "Brit,  and  For.  Med.  Rev.,"  Oct.,  1841.  It 
may  be  surmised  that  in  many  cases  of  angina  pectoris,  in  which  no  lesion  adequate  to  ac- 
count for  death  could  be  discovered,  some  affection  of  the  cardiac  plexus  might  have  been 
traced  on  more  careful  examination. 


ACTION   OF   THE   HEART.  471 

excited,  save  by  the  successive  recurrence  of  stimuli  at  regular  intervals,  as  in 
the  act  of  Respiration.  It  is  the  continuance  of  activity  after  all  conceivable 
sources  of  stimulation  have  been  withdrawn,  which  constitutes  the  real  perplexity 
of  the  case;  and  if  the  operation  of  such  stimuli  be  admitted  as  the  sources  of 
reflex  action,  they  may  with  equal  propriety  be  regarded  as  directly  acting  upon 
the  contractile  fibre — which,  as  already  shown,  is  much  more  amenable  to  such 
direct  excitation,  than  it  is  to  nervous  influence,  and  preserves  its  capacity  for 
being  impressed  by  the  former  during  a  much  longer  period  than  it  remains 
capable  of  responding  to  the  latter. 

498.  A  more  satisfactory  mode  of  accounting  for  the  rhythmical  movements 
of  the  Heart,  appears  to  the  Author  to  lie  in  regarding  them  as  an  expression 
of  the  peculiar  vital  endowments  of  its  Muscular  tissue ;  and  to  believe  that,  so 
long  as  this  tissue  retains  its  integrity,  and  the  other  necessary  conditions  are 
supplied,  so  long  is  an  alternation  of  contraction  and  relaxation  the  characteristic 
and  constant  manifestation  of  its  vital  activity — just  as  ciliary  movement  is  in 
cells  of  one  class,  and  secreting  action  in  those  of  another  (§  110).     The  fact 
that  this  movement  is  seen  to  commence  in  the  embryo-heart,  when  as  yet  its 
parietes  consist  of  ordinary- eel  Is,  and  no  nervous  structure  exists  either  in  its 
own  substance  or  in  the  body  at  large,  is  an  important  confirmation  of  this  doc- 
trine ;  whilst  the  same  fact  stands  in  complete  opposition,  to  the  idea,  that  ner- 
vous force  is  in  any  way  concerned  in  maintaining  this  rhythmical  action. — But 
it  may  be  said  that  in  attributing  to  the  muscular  structure  of  the  heart  a  self- 
moving  power,  we  really  only  throw  back  the  question  into  the  obscurity  from 
which  the  Physiologist  has  sought  to  draw  it.1     Such  is  far  from  being  the  case, 
however,  if  it  can  be  shown  that  this  self-moving  power  is  nothing  else  than  an 
exertion  of  ordinary  Muscular  Contractility  under  peculiar  conditions;  and  if 
analogous  phenomena  can  be  shown  to  present  themselves  elsewhere.2     To  this 
point  attention  will  now  be  directed. 

499.  We  have  seen  that  the  contraction  of  any  Muscle,  upon  the  application 
of  a  stimulus,  must  be  attributed  to  an  exercise  of  Vital  Force  engendered  by 
previous  acts  of  Nutrition.     The  stimulus  is  not  the  source  of  the  force,  but  only 
supplies  some  condition  which  is  requisite  for  its  manifestation;  just  as  the  fall 
of  a  spark  upon  gunpowder  causes  its  explosion  (the  force  of  which  is  the  expres- 
sion of  the  change  in  the  chemical  condition  of  its  components,  which  change  is 
dependent  upon  their  pre-existing  affinities),  or  as  the  application  of  the  discharger 
to  the  Leyden  jar  (which  has  been  charged  by  the  previous  action  of  the  Elec- 
trical machine)  liberates,  so  to  speak,  its  pent-up  electricity,  and  allows  this  to 
display  itself  as  an  active  force.     Now  just  as  the  Leyden  jar  may  be  so  charged 
with  electricity  as  to  discharge  itself  spontaneously,  so  is  it  easy  to  conceive  that 
a  Muscle  may  be  so  charged  with  motility  (or  motor  force)  as  to  execute  sponta- 
neous contractions;  and  of  the  existence  of  such  a  condition,  we  have  valid 
evidence.     For  there  are  many  local  phenomena  of  cramp  and  spasm,  which 
cannot  be  fairly  attributed  to  a  perverted  reflex  action  of  the  nervous  system, 
and  which  can  scarcely  be  referred  to  anything  else  than  an  overcharge  of  mus- 
cular power.     So,  again,  the  action  of  the  uterus,  as  shown  not  merely  in  the 

1  In  so  far  as  it  attributes  the  Heart's  action  to  causes  originating  in  itself,  this  doctrine 
may  be  considered  as  nothing  else  than  the  old  notion  of  the  inherent  "pulsific  virtue"  of 
the  organ,  so  happily  ridiculed  by  Moliere  and  Swift.     But  there  is  really  just  the  same  dif- 
ference between  the  two,  as  between  the  doctrine  of  Vital  Forces,  which  it  has  been  the 
Author's  object  to  unfold  in  this  and  the  companion  Treatise,  and  the  old  notion  of  the 
"vital  principle"  which  was  held  to  account  for  everything  not  otherwise  explicable. 

2  It  cannot  be  too  constantly  borne  in  mind,  in  this  and  other  instances,  to  explain  a  phe- 
nomenon in  Physiology  or  in  any  other  science  whatever,  is  nothing  else  than  to  show  that 
it  is  conformable  to  some  general  law,  and  that  it  is  thus  a  result  of  some  previously  recog- 
nized cause,  which  is  common  to  it  with  a  number  of  other  previously  observed  phenomena. 
(See  Mr.  John  S.  Mill's  "System  of  Logic,"  book  iii.  chap,  xii.) 


^5  OF   THE   CIRCULATION   OF   THE    BLOOD. 

final  parturient  effort,  but  in  local  contractions  that  frequently  occur  during  the 
later  months  of  gestation  (simulating  the  movements  of  the  foetus),  are  more 
satisfactorily  accounted  for  by  considering  them  as  a  discharge  of  accumulated 
power,  than  in  any  other  mode  (§110).  And  we  have  seen  that  muscles  which 
are  ordinarily  excited  to  rhythmical  movement  through  the  medium  of  the  nerv- 
ous system,  may  execute  these  movements  of  themselves,  when  this  source  of 
stimulation  has  been  cut  off,  and  their  motility  has  accumulated  through  inaction 
(§  318,  note). — It  is  not  very  difficult,  then,  to  conceive,  that  the  ordinary  rhyth- 
mical movements  of  the  heart  may  be  due  to  a  simple  excess  of  this  motility, 
which  is  continually  being  supplied  by  the  nutritive  operations,  and  is  as  con- 
stantly discharging  itself  in  contractile  action.  And  that  this  is  the  true  view 
of  the  case,  is  further  indicated  by  the  phenomena  attending  the  cessation  of  the 
heart's  action.  For  if  a  stimulus  be  applied  to  it  soon  after  it  has  ceased  to 
execute  spontaneous  movements,  this  stimulus  is  followed,  not  (as  in  ordinary 
muscles)  by  a  single  contraction  followed  by  relaxation,  but  by  a  succession  of 
contractions  and  relaxations;  thus  indicating  that  a  higher  degree  of  motility 
than  that  of  an  ordinary  muscle  still  persists  in  its  tissue.1  Gradually,  however, 
the  number  of  repetitions  becomes  smaller  and  smaller,  until  the  application  of 
the  stimulus  excites  but  a  single  contraction;  thus  indicating  that  the  motility 
of  the  heart  has  been  reduced,  by  the  cessation  of  the  nutritive  operations,  to 
that  of  an  ordinary  muscle.3 — If  we  pass  from  this  comparison  of  the  Heart  with 
other  muscles,  to  the  general  phenomena  of  rhythmical  movement  in  the  Animal 
and  Vegetable  kingdoms,  the  proof  furnished  by  analogy  that  the  immediate 
source  of  its  action  lies  entirely  within  itself,  becomes  much  stronger ;  but  this 
part  of  the  subject  has  been  treated  of  elsewhere.3 

500.  This  view  of  the  case  is  not  in  the  least  inconsistent  with  the  fact,  that 
the  ordinary  rhythmical  actions  of  the  heart  may  be  considerably  modified,  both 
as  to  their  rate  and  their  force,  by  stimuli  of  various  kinds  brought  to  bear  upon 
its  tissue,  either  through  the  nervous  system,  or  by  direct  contact.     Of  the 
former  we  have  an  example  in  the  influence  of  the  emotions;  and  of  the  latter 
in  the  violent  action  excited  by  an  unusual  rush  of  blood  towards  the  heart,  in 
consequence  of  sudden  muscular  exertion. 

501.  When  the  Heart  is  exposed  in  a  living  animal,  and  its  movements  are 
attentively  watched,  they  are  seen  to  follow  each  other  with  great  regularity. 
In  an  active  and  vigorous  state  of  the  circulation,  however,  they  are  so  linked 
together,  that  it  is  not  easy  to  distinguish  them  into  periods;  both  Auricles  con- 
tracting and  also  dilating  simultaneously,  and  both  Ventricles  doing  the  same. 
The  systole  or  contraction  of  the  Ventricles  corresponds  with  the  projection  of 
blood  into  the  arteries;  whilst  the  diastole  or  dilatation  of  the  Ventricles  coin- 
cides with  the  collapse  of  the  arteries.     The  contraction  of  the  Ventricles,  and 
that  of  the  Auricles,  alternate  with  one  another ;  each  taking  place  (for  the  most 
part,  at  least),  during  the  dilatation  of  the  other.     But  there  is  a  period  during 

1  This  is  a  phenomenon  which  has  no  parallel  among  any  of  the  manifestations  of  proper 
reflex  action. 

2  [M.  Duval,  teacher  of  Anatomy  at  Brest,  has  seen  the  heart  pulsating  in  a  decapitated 
criminal  twenty  minutes  after  death,  and  continuing  with  perfectly  regular  action  for  an 
hour,  at  the  rate  of  forty-four  pulsations  in  the  minute.     The  movements  were  especially 
observed  in  the  left  auricle. 

The  divided  ends  of  the  carotid  arteries  were  also  projected  in  successive  jerks,  at  the 
same  time  ejecting  small  quantities  of  blood.  The  jugular  veins  bled  continuously. 

It  should  be  stated  that  galvanism  was  applied  to  the  spine,  before  the  chest  was 
opened,  producing  movements  of  expiration  and  inspiration,  although  this  would  scarcely 
be  considered  as  explanatory  of  this  continuance  of  the  heart's  action,  of  which  a  much 
more  satisfactory  reason  is  given  by  the  author.  It  may  have  been  the  exciting  cause  of 
renewed  action  after  entire  cessation. — ED.] 

8  See  \  110;  also  "Princ.  of  Phys.,  Gen.  and  Comp.,"  CHAP,  xix.,  Am.  Ed. 


ACTION    OF   THE    HEART.  473 

which  the  Auricles  and  Ventricles  of  both  sides  are  dilating  together.  This 
occurs  during  the  first  part  of  the  Ventricular  diastole;  for  at  the  conclusion  of 
the  systole,  the  Auricles  are  far  from  being  completely  filled,  and  they  go  on 
receiving  an  additional  supply  from  the  great  Veins  (a  portion  of  which,  how- 
ever, passes  at  once  into  the  Ventricles)  until  after  the  middle  of  the  Ventricular 
diastole,  by  which  time  they  become  fully  distended  and  immediately  contract. 
The  contraction  of  the  Auricles  is  synchronous,  therefore,  with  only  the  second 
stage  of  the  Ventricular  diastole ;  and  their  dilatation  is  going  on  during  the 
whole  period  of  the  Ventricular  systole.  Thus  whilst  the  entire  period  that 
intervenes  between  one  pulsation  and  another  is  nearly  equally  divided  between 
the  systole  and  diastole  of  the  Ventricles,  the  division  is  very  unequal  as  regards 
the  Auricle;  scarcely  more  than  one-eighth  of  the  whole  being  occupied  in  their 
contraction,  and  the  remainder  being  taken  up  by  their  dilatation.  The  follow- 
ing tabular  view  will  perhaps  make  the  relations  of  the  several  parts  of  this 
series  more  intelligible. 

AURICLES.  VENTRICLES. 

7  f  Dilatation.  Contraction.  £ 

T  \  Continued  Dilatation.  First  stage  of  Dilatation.  "»  x 

£     Contraction.  Second  stage  of  Dilatation.  J  2 

502.  In  the  systole  of  the  Ventricles,  their  surface  becomes  rugous;  the 
superficial  veins  swell ;  the  carneaB  columnee  of  the  left  ventricle  are  delineated ; 
and  the  curved  fibres  of  the  conical  termination  of  the  left  ventricle,  which  alone 
constitutes  the  apex  of  the  heart,  become  more  manifest.1  During  their  con- 
traction, the  form  of  the  Ventricles  undergoes  a  very  marked  change,  the  apex 
of  the  heart  being  drawn  up  towards  its  base,  and  its  whole  shape  becoming 
much  more  globular.  The  movement  of  the  apex,  however,  is  by  no  means  a 
simple  elevation;  for,  owing  to  ihe  peculiar  arrangement  of  the  fibres  of  this 
part  of  the  heart,  it  is  made  to  describe  a  spiral  curve  from  right  to  left,  and 
from  behind  forwards.  It  is  to  this  change  in  the  form  of  the  heart,  and  in 
the  position  of  its  apex,  rather  than  to  change  in  the  place  of  the  organ  as  a 
whole,  that  we  are  to  attribute  its  impulse  against  the  parietes  of  the  chest ;  for 
if  any  advance  and  recedence  do  take  place,  from  the  various  causes  which  have 
been  assigned  by  different  observers  (such  as  the  pressure  of  the  blood  in  the 
direction  opposite  to  that  of  the  orifices  through  which  it  is  being  impelled,  the 
tendency  of  the  aorta  to  straighten  itself  when  distended  with  blood,  and  the 
elastic  recoil  of  the  parts  about  the  base  of  the  heart),  this  must  be  extremely 
trifling  in  its  amount,  since  all  these  causes  require  distension  of  the  organ  with 
blood  for  their  operation,  and  the  tilting  forward  of  the  lower  part  of  the  heart 
still  ensues  when  its  apex  has  been  cut  off,  and  no  such  tension  can  be  exercised. — 
The  diastole  of  the  ventricles,  according  to  Cruveilhier  (loc.  cit.),  has  the  rapidity 
and  energy  of  an  active  movement;  triumphing  over  pressure  exercised  upon 
the  organ,  so  that  the  hand  closed  upon  it  is  opened  with  violence.  This  is  an 
observation  of  great  importance;  and  it  concurs  with  observations  made  upon 
the  heart  when  emptied  of  blood,  to  show  that  the  diastole  is  not  a  mere  relaxa- 
tion of  the  muscular  fibres,  permitting  the  cavity  to  be  distended,  but  is  effected 
by  some  power  inherent  in  the  walls  themselves.3  Even  the  dilatation  of  the 
Auricles  appears  to  be  much  greater  than  can  be  accounted  for  by  any  vis  a 
tergo  (which,  as  will  hereafter  appear,  is  extremely  small  in  the  venous  system),  or 

1  See  the  account  given  by  M.  Cruveilhier  of  a  remarkable  case  of  Ectopia  Cordis,  in 
"Gazette  Medicale,"  Aout  7,  1841. 

2  The  only  power  whose  existence  has  been  hitherto  admitted  as  competent  to  produce 
such  an  effect  is  the  elasticity  of  the  tissues  composing  the  walls  of  the  heart.     The  Author 
would  suggest,  however,  whether  there  may  not  exist  in  Muscle  an  active  force  of  elon- 
gation, as  well  as  an  active  force  of  contraction ;  arising  from  the  mutual  repulsion  of  par- 
ticles whose  mutual  attraction  is  the  occasion  of  the  shortening. 


474 


OF   THE   CIRCULATION   OF   THE   BLOOD. 


by  the  elasticity  of  its  substance ;  for  it  was  observed  in  this  case  to  be  so  great, 
that  the  right  auricle  seemed  ready  to  burst,  so  great  was  its  distension,  and  so 
thin  were  its  walls.  Moreover,  the  large  veins  near  the  heart  contract  simulta- 
neously with  the  auricle,  and  not  whilst  it  is  dilating ;  so  that  they  can  have  no 
influence  in  causing  its  distension. 

503.  The  course  of  the  circulating  fluid  through  the  Heart,  and  the  action  of 
its  different  valves,  will  now  be  briefly  described. — The  Venous  blood,  which  is 
returned  by  the  ascending  and  descending  Vena  Cava,  enters  the  right  Auricle 
during  its  diastole;  part  of  it  flows  on,  as  already  mentioned,  into  the  right 
Ventricle  during  the  earlier  portion  of  its  diastole;  but  the  Auricle,  being  filled 
before  the  Ventricle,  then  contracts,  and  discharges  its  contents  through  the 

Fig.  139. 


The  Anatomy  of  the  Heart :  1,  the  right  auricle ;  2,  the  entrance  of  the  superior  vena  cava ;  3,  the  entrance 
of  the  inferior  cava ;  4,  the  opening  of  the  coronary  vein,  half  closed  hy  the  coronary  valve ;  5,  the  Eustachian 
valve ;  6,  the  fossa  ovalis,  surrounded  by  the  annulus  ovalis ;  7,  the  tuherculum  Loweri ;  8,  the  musculi  pecti- 
nati  in  the  appendix  auriculae;  9,  the  auriculo-ventricular  opening ;  10,  the  cavity  of  the  right  ventricle ;  11, 
the  tricuspid  valve,  attached  by  the  chordae  tendineae  to  the  carneae  columnas  (12) ;  13,  the  pulmonary  artery, 
guarded  at  its  commencement  by  three  semilunar  valves ;  14,  the  right  pulmonary  artery,  passing  beneath 
the  arch  and  behind  the  ascending  aorta ;  15,  the  left  pulmonary  artery,  crossing  in  front  of  the  descending 
aorta ;  *,  the  remains  of  the  ductus  arteriosus,  acting  as  a  ligament  between  the  pulmonary  artery  and  arch  of 
the  aorta ;  the  arrows  mark  the  course  of  the  venous  blood  through  the  right  side  of  the  heart ;  entering  the 
auricle  by  the  superior  and  inferior  cava,  it  passes  through  the  auriculo-ventricular  opening  into  the  ventricle, 
and  thence  through  the  pulmonary  artery  to  the  lungs ;  16,  the  left  auricle ;  17,  the  openings  of  the  four  pul- 
monary veins ;  1&,  the  auriculo-ventricular  opening ;  19,  the  left  ventricle ;  20,  the  mitral  valve,  attached  by 
ita  chordae  tendineae  to  two  large  columnae  carneae,  which  project  from  the  walls  of  the  ventricle ;  21,  the 
commencement  and  course  of  the  ascending  aorta  behind  the  pulmonary  artery,  marked  by  an  arrow ;  the 
entrance  of  the  vessel  is  guarded  by  three  semilunar  valves;  22,  the  arch  of  the  aorta.  The  comparative 
thickness  of  the  two  ventricles  is  shown  in  the  diagram.  The  course  of  the  arterial  blood  through  the  left 
side  of  the  heart  is  marked  by  arrows.  The  blood  is  brought  from  the  lungs  by  the  four  pulmonary  veins 
into  the  left  auricle,  and  passes  through  the  auriculo-ventricular  opening  into  the  left  ventricle,  whence  it  is 
conveyed  by  the  aorta  to  every  part  of  the  body. 

tricuspid  valves  into  the  Ventricle,  which  it  thus  completely  distends.  The  re- 
flux of  blood  into  the  veins  during  the  auricular  systole  is  impeded  by  the  con- 
traction of  their  own  walls,  and  by  the  valves  with  which  they  are  furnished ; 
but  these  valves  are  so  formed,  as  not  to  close  accurately,  especially  when  the 
tubes  are  distended;  so  that  a  small  amount  of  reflux  usually  takes  place,  and 
this  is  much  increased  when  there  is  any  obstruction  to  the  pulmonary  circula- 
tion. Whilst  the  right  Ventricle  is  contracting  upon  the  blood  that  has  entered 
it,  the  carneas  columnse,  which  contract  simultaneously  with  its  proper  walls, 
put  the  chordse  tendineae  upon  the  stretch ;  and  these  draw  the  flaps  of  the  Tri- 
cuspid valve  into  the  auriculo-ventricular  axis.  The  blood  then  getting  behind 


ACTION   OF   THE    HEART.  475 

them,  and  being  compressed  by  the  contraction  of  the  ventricle,  forces  the  flaps 
together,  in  such  a  manner  as  to  close  the  orifice ;  but  they  do  not  fall  suddenly 
against  each  other,  as  is  the  case  with  the  semilunar  valves,  since  they  are  re- 
strained by  the  chordae  tendineaa;  whence  it  is,  that  no  sound  is  produced  by 
their  closure.  The  blood  is  expelled  by  the  ventricular  systole  into  the  Pulmon- 
ary Artery,  which  it  distends,  passing  freely  through  its  Semilunar  valves  ;  but 
as  soon  as  the  vis  a  teryo  ceases,  and  reflux  might  take  place  by  the  contraction 
of  the  arterial  walls,  the  valves  are  filled  out  by  the  backward  tendency  of  the 
blood,  and  completely  check  the  return  of  any  portion  of  it  into  the  ventricle. 
The  blood,  after  having  circulated  through  the  lungs,  returns  as  Arterial  blood, 
by  the  Pulmonary  Veins,  to  the  left  Auricle;  whence  it  passes  through  the 
Mitral  valve  into  the  left  Ventricle,  and  thence  into  the  Aorta  through  its  Semi- 
lunar  valves — in  the  same  manner  with  that  on  the  other  side,  as  just  described. 
504.  There  are,  however,  some  important  differences  in  the  structure  and 
functional  actions  of  the  two  divisions  of  the  Heart,  which  should  be  here 
adverted  to.  The  walls  of  the  left  Ventricle  are  considerably  thicker  than  those 
of  the  right;  and  its  force  of  contraction  is  much  greater.  The  following  are 
the  comparative  results  of  M.  Bizot's  measurements,1  taking  the  average  of 
males  from  16  to  79  years. 

BASE.  MIDDLE.  APEX. 

Left  Ventricle  4£    lines  5£  lines  3|    lines. 

Right  Ventricle         .         .         lj|  lines  If  lines  I3'ff  lines. 

In  the  female,  the  average  thickness  is  somewhat  less.  It  will  be  seen,  that  the 
point  of  greatest  thickness  in  the  left  Ventricle  is  near  its  middle;  while  in  the 
right,  it  is  nearer  the  base.  The  thickness  of  the  former  goes  on  increasing 
during  all  periods  of  life,  from  youth  to  advanced  age;  whilst  that  of  the  right 
is  nearly  stationary.  The  left  Auricle  is  somewhat  thicker  than  the  right;  the 
average  thickness  of  the  former  being,  according  to  Bouillaud,  a  line  and  a  half; 
whilst  that  of  the  latter  is  only  a  line.  In  regard  to  the  relative  capacities  of 
the  right  and  left  cavities,  much  difference  of  opinion  has  prevailed.  The  right 
Auricle  is  generally  allowed  to  be  somewhat  more  capacious  than  the  left;  and 
the  same  is  commonly  taught  of  the  right  Ventricle.  So  much  fallacy  may  arise, 
however,  from  the  peculiar  condition  of  the  animal  at  the  moment  of  death,  that 
this  is  not  easily  proved,  and  is  indeed  by  no  means  certain. — The  average  capa- 
city of  the  cavities  may  be  estimated,  in  the  full-sized  Heart,  at  about  three 
ounces;  that  of  the  Auricles  being  probably  a  little  less;  and  that  of  the  Ven- 
tricles a  little  greater.  It  has  been  shown  that  the  Ventricles  receive  more  blood 
from  the  Auricles,  than  the  latter  could  transmit  to  them  by  simply  emptying 
themselves  once. — There  is  a  well-known  anatomical  difference  between  the 
auriculo- ventricular  valves  on  the  two  sides,  which  has  giyen  rise  to  the  diversity 
of  name.  This  seems,  from  the  researches  of  Mr.  King,alo  be  connected  with 
an  important  functional  difference.  The  Mitral  valve  closes  much  more  perfectly 
than  the  Tricuspid;  and  the  latter  is  so  constructed,  as  to  allow  of  considerable 
reflux,  when  the  cavities  are  greatly  distended.  Many  occasional  causes  tend 
to  produce  an  accumulation  of  blood  in  the  venous  system,  and  in  the  right  side 
of  the  Heart;  thus,  any  obstruction  to  the  pulmonary  circulation,  cold,  com- 
pression of  the  venous  system  by  muscular  action,  &c.,  are  known  to  favor  such 
a  condition.  This  is  a  state  of  peculiar  danger,  from  the  liability  which  over- 
distension  of  the  Ventricular  cavity  has,  to  produce  a  state  of  muscular  para- 
lysis; and  in  the  structure  of  the  Heart  itself,  there  seems  to  be  a  provision 
against  it.  For,  when  the  ventricle  is  thus  distended,  the  Tricuspid  valves  do 
not  close  properly ;  and  a  reflux  of  blood  is  permitted,  not  only  into  the  Auricle, 

1  "M£m.  de  la  Soc.  Medic.  d'Observation  de  Paris,"  torn.  i. 

2  "Guy's  Hospital  Reports,"  vol.  ii. 


476  OF   THE   CIRCULATION   OF   THE   BLOOD. 

but  also  (through  the  imperfect  closure  of  their  valves  under  the  same  circum- 
stances) into  the  large  veins.  This  is  proved  by  the  fact,  several  times  observed 
by.  Dr.  J.  Reid  in  his  experiments  upon  Asphyxia,  &c.,  that  when  the  action  of 
the  right  ventricle  had  ceased  from  over-distension,  he  could  frequently  re-excite 
it,  not  merely  by  puncturing  its  walls,  but  by  making  an  opening  in  the  jugular 
vein.1  This  fact  evidently  affords  an  indication  of  great  importance  in  the  treat- 
ment of  Asphyxia ;  and  it  explains  the  reflux  of  blood,  or  venous  pulse,  which  is 
frequently  observed  in  cases  of  pulmonary  disease,  and  which,  according  to  Mr. 
King,  always  exists  even  in  health,  though  in  a  less  striking  degree. 

505.  When  the  ear  is  applied  over  the  cardiac  region,  during  the  natural 
movements  of  the  Heart,  two  successive  sounds  are  heard,  each  pair  of  which 
corresponds  with  one  pulsation ;  there  is  also  an  interval  of  silence  between  each 
recurrence,  and  the  sound  that  immediately  follows  this  interval  is  known  as 
the  first  sound,  the  other  as  the  second. — The  first  sound  is  dull  and  pro- 
longed; it  is  evidently  synchronous  with  the  impulse  of  the  Heart  against  the 
parietes  of  the  chest,  and  also  with  the  pulse,  as  felt  near  the  heart;  it  must, 
therefore,  be  produced  during  the  Ventricular  Systole. — The  second  sound, 
which  is  short  and  sharp,3  follows  so  immediately  upon  the  conclusion  of  the 
first,  that  it  cannot  take  place  during  the  auricular  systole,  as  some  have  sup- 
posed, but  must  be  assigned  to  the  first  stage  of  the  ventricular  diastole,  when 
the  auricles  also  are  dilating.     With  regard  to  the  relative  duration  of  the  two 
sounds  and  of  the  interval,  widely  different  estimates  have  been  formed.    Thus 
Laennec  considered  the  lengths  of  the  periods  of  sound  and  silence  to  be  respect- 
ively 3-4ths  and  l-4th  of  the  whole  interval  between  one  pulse  and  another ; 
by  Dr.  Williams,  and  by  Barth  and  Roger,  the  relative  lengths  of  these  periods 
have  been  estimated  at  2-3ds  and  l-3d;  whilst  the  recent  experiments  of  Volk- 
mann3  (made  by  adjusting  two  pendulums  to  vibrate  precisely  in  the  two  periods) 
indicate  that  they  are  almost  precisely  equal. 

506.  The  cause  of  these  sounds,  and  more  especially  of  the  first,  has  been  a 
subject  of  much  discussion.     A  number  of  very  distinct  actions  are  taking  place 
during  the  period  of  its  production ;  and  each  of  these  has  been  separately  fixed 
on  as  competent  to  produce  it.     Thus  we  have  (a)  the  impulse  of  the  heart 
against  the  parietes  of  the  chest,  (6)  the  contraction  of  the  muscular  walls  of 
the  ventricles,  (c)  the  tension  of  the  valves  of  the  auriculo-ventricular  orifices, 
and  the  backward  impulse  of  the  blood  against  them,  (d)  the  rush  of  blood 
through  the  narrowed  orifices  of  the  aorta  and  pulmonary  artery,  and  (e)  the 
general  molecular  collision  of  the  particles  of  the  blood  amongst  each  other,  and 
their  friction  against  the  walls  of  the  ventricles.     Each  of  these  causes  has 
probably  some  share  in  the  production  of  the  result. 

a.  That  the  first  sound  is  partly  due  to  the  impulse,  seems  proved  by  the  fact, 
that  when  the  impulse  is  prevented,  by  the  removal  of  the  portion  of  the  wall 
of  the  chest  against*  which  it  takes  place,  the  sound  is  much  diminished  in 
intensity ;  and  also  by  the  circumstance,  that,  when  the  ventricles  contract  with 
vigour,  the  greatest  intensity  of  the  sound  is  over  the  point  against  which  the 
impulse  takes  place.     Moreover,  the  prolonged  nature  of  the  sound  is  by  no 
means  inconsistent  with  this  view;  since  the  impulse  is  not  a  mere  stroke,  so 
much  as  a  continued  pressure.     But  that  the  sound  is  not  entirely  due  to  this 
cause,  is  also  evident  from  the  fact,  that  it  may  still  be  heard  when  the  heart  is 
contracting  out  of  the  body,  or  when  the  impulse  cannot  take  place. 

b.  That  the  sound  is  partly  muscular  (§  330)  would  appear  from  the  fact 
that  it  may  be  still  perceived  after  the  heart  has  been  removed  from  the  body 

1  Op.  cit.,  Chap.  iii. 

2  The  difference  between  these  two  sounds  is  well  expressed  (as  Dr.  C.  J.  B.  Williams 
has  remarked)  by  articulating  the  syllables  lubb,  dup. 

3  "Die  Hamodynamik,  nach  Versuchen,"  p.  3G4. 


ACTION    OF   THE   HEART.  4V7 

and  completely  drained  of  its  blood.1  But  that  this  is  not  its  only  source,  is 
shown  by  the  great  diminution  in  its  intensity,  which  is  observable  under  such 
circumstances. 

c.  That  the  sudden  tension  of  the  auriculo-ventricular  valves,  with  the  reflux 
of  the  blood  against  them,  at  the  commencement  of  the  ventricular  systole,  is  a 
cause  of  sound,  would  seem  to  be  indicated  by  the  analogy  of  the  semilunar 
valves;  and  an  experiment  by  Valentin,2  in  which  a  sound  in  some  degree  re- 
sembling the  first  sound   of  the  heart  was  produced  by  the  impulse  of  fluid 
against  a  tense  membrane,  has  been  adduced  in  confirmation  of  this  view.     But 
it  is  to  be  borne  in  mind  that  these  valves  cannot  close  together  with  the  same 
suddenness  as  do  the  semilunar,  being  restrained  by  the  spring-like  tension  of 
the  earner  columnae;   and,  moreover,  even  admitting  a  sound  to  be  produced 
by  their  closure,  such  a  sound  would  be  momentary,  and  would  not  possess  the 
prolonged  character  of  the  true  first  sound.     Still  it  is  not  improbable  that  the 
tension  of  these  valves  serves  to  augment  by  resonance  the  sounds  produced  in 
other  ways. 

d.  That  the  rush  of  blood  through  the  narrowed  orifices  of  the  great  arterial 
trunks  is  really  a  cause  of  sound,  is  indicated  by  the  results  of  experiments 
made  upon  tubes  out  of  the  body,  and  upon  large  bloodvessels  through  which 
the  blood  is  circulating ;  for  any  diminution  of  the  caliber  of  a  tube  through 
which  fluid  is  rapidly  moving,  gives  rise  to  a  continuous  murmur.     And  that 
this  cause  is  in  operation  in  the  heart,  is  specially  indicated  by  the  observations 
of  Cruveilhier  upon  the  case  already  cited;  for  he  noticed  that  (the  effect  of  the 
impulse  being  there  in  abeyance)  the  greatest  intensity  of  the  first  sound  was, 
like  that  of  the  second,  at  the  base  of  the  heart,  in  the  region  from  which  the 
great  vessels  originate,  whilst  he  could  discover  no  production  of  sound  in  the 
region  of  the  auriculo-ventricular  valves. 

e.  Lastly,  that  the  collision  of  the  particles  of  the  blood  with  each  other,  and 
with  the  tense  muscular  parietes  of  the  heart,,  together  with  its  movement  over 
the  inequalities  of  the  internal  surface  of  the  ventricle,  will  become  a  cause  of 
sound,  may  be  suspected  from  what  happens  elsewhere,  and  more  especially  from 
the  production  of  a  very  distinct  sound  by  the  movement  of  blood  in  the  interior 
of  an  aneurism;3  but  that  this  cause,  if  it  have  a  real  existence,  is  much  inferior 
in  potency  to  the  preceding,  appears  from  the  fact  that  it  cannot  be  distinguished 
from  it ;  and  that  neither  separately  nor  combined  do  these  give  a  sufficient 
account  of  the  phenomenon,  is  obvious  from  the  persistence  of  a  sound  after  the 
heart  has  been  completely  emptied  of  its  blood. 

507.  It  is  only  by  thus  regarding  the  first  sound  as  made  up  by  several  fac- 
tors, that  we  can  adequately  account  for  the  operation  of  pathological  causes  in 
modifying  it;  since  the  greater  part  of  the  bruits  and  murmurs  that  are  pro- 
duced by  morbid  changes  in  the  heart  and  in  its  valves,  are  really  modifications 
of  the  natural  sound,  not  additions  to  it. 

508.  That  the  second  sound  is  produced  in  the  act  of  closure  of  the  Semilunar 
valves,  is  now  almost  universally  admitted;  the  simple  hooking-back  one  of  these 
valves  by  a  curved  needle  against  the  side  of  the  artery,  so  as  to  permit  a  reflux 
of  blood  into  the  ventricle,  being  sufficient  to  suppress  this  sound  altogether. 
Whether  it  proceeds  from  the  tension  of  the  valves  themselves,  or  from  the  recoil 
of  the  blood  against  them,  or  from  both  causes  combined,  has  not  been  clearly 
determined;  probably  the  last  is  the  true  account  of  it. — When  the  first  sound 
is  altered  by  disease  of  the  semilunar  valves,  occasioning  obstruction  to  the  exit 
of  blood,  the  second  sound  also  is  affected  in  its  character;  and  if  the  disease  be 
of  such  a  kind  as  to  prevent  these  valves  from  effectually  closing,  a  reflux  of 

1  See  the  Report  of  the  London  Committee  upon  the  Sounds  of  the  Heart,  in  the  "Trans, 
of  Brit.  Assoc."  for  1836. 

2  "  Lehrbuch  der  Physiologic,"  band  i.  p.  427. 

3  See  the  "  Report  of  the  Dublin  Committee  of  the  British  Association,"  loc.  cit. 


478  OF   THE   CIRCULATION    OF   THE   BLOOD. 

blood  takes  place  into  the  ventricle  at  the  time  of  its  diastole,  causing  a  rushing 
sound,  analogous  to  the  ordinary  first  sound,  or  to  some  of  its  modifications. 
Thus  the  second  sound  may  come  to  acquire  so  completely  the  character  of  the 
first,  that  it  is  difficult  to  distinguish  the  two  in  any  other  way  than  by  the 
synchronousness  of  the  first  with  the  heart's  stroke  and  with  the  pulse  in  the 
arteries.1 

509.  There  seems  adequate  reason  to  believe  that  the  whole,  or  very  nearly 
the  whole,  of  the  blood  contained  in  the  Ventricles,  is  discharged  from  them  at 
each  systole ;  for  the  left  ventricle  is  very  frequently  found  quite  empty  after 
death ;  and  if  a  transverse  section  be  made  through  the  heart,  when  in  a  state 
of  well-marked  rigor  mortis  (which  may  be  considered  as  representing  its  ordi- 
nary state  of  complete  contraction),  the  ventricular  cavity  is  found  to  be  entirely 
obliterated.3  From  the  capacity  of  the  cavity  in  its  state  of  fullest  dilatation, 
it  can  scarcely  be  admitted  that  more  than  3  oz.  of  blood  can  be  propelled  by 
either  ventricle  at  each  systole;3  and  thus,  if  we  estimate  the  whole  amount  of 
blood  at  18  Ibs.  (§  136),  this  would  require  96  strokes  for  its  passage  through 
either  side  of  the  heart;  or,  reckoning  72  pulsations  to  a  minute,  the  time  elaps- 
ing before  any  particle  could  return  to  a  given  point  after  once  passing  it  (sup- 
posing it  not  to  be  sent  elsewhere),  would  be  1|  minute.  Between  any  such 
estimates,  however,  and  those  which  are  founded  upon  experimental  inquiry  into 
the  time  required  for  the  passage  of  substances  introduced  into  the  circulating 
current  from  one  part  of  the  system  to  another,  there  is  a  discrepancy  which  it 
is  very  difficult  to  reconcile.  The  earliest  of  such  experiments  were  those  of 
Hering,4  who  endeavored  to  ascertain  the  rapidity  of  the  circulation,  by  intro- 
ducing prussiate  of  potash  into  one  part  of  the  system,  and  drawing  blood  from 
another.  He  states  that  he  detected  this  salt,  in  blood  drawn  from  one  of  the 
jugular  veins  of  the  Horse,  within  20  or  30  seconds  after  it  had  been  introduced 
into  the  other;  in  which  brief  space  the  blood  must  have  been  received  by  the 
heart,  must  have  been  transmitted  through  the  lungs,  have  returned  to  the  heart 
again,  have  been  sent  through  the  carotid  artery,  and  have  traversed  its  capil- 
laries. From  experiments  of  a  similar  nature  upon  other  veins,  he  states  that 
the  salt  passed  from  the  jugular  vein  into  the  saphena  in  twenty  seconds ;  into 
the  masseteric  artery  in  from  15  to  20  seconds;  into  the  external  maxillary 
artery  in  from  10  to  25  seconds ;  and  into  the  metatarsal  artery  in  from  20  to  40 
seconds.5  These  experiments  have  been  fully  confirmed  by  those  of  Poisseuille,6 

1  On  the  subject  of  the  Sounds  of  the  Heart,  the  various  treatises  on  Auscultation  by 
Williams,  Blakiston,  Hughes,  Walshe,  Davis,  Skoda,  Earth  and  Roger,  Weber,  and  others 
may  be  advantageously  consulted ;  see  also  Dr.  Bellingham's  Lectures  on  Diseases  of  the 
Heart,  in  the  "  Medical  Gazette"  for  1850 ;  the  account  of  Hamernjk's  investigations  in 
the  "Edinb.  Monthly  Journal,"  Jan.,  1849;  and  those  of  Kiwisch  in  the  "Brit,  and  For. 
Med.-Chir.  Rev.,"  April,  1852. 

2  Kirkes  and  Paget's  "Handbook  of  Physiology,"  2d  edit.,  p.  80. 

3  The  total  quantity  discharged  from  either  ventricle  of  the  human  Heart  at  each  systole, 
is  estimated  by  Valentin  at  5.3  oz. ;  and  by  Volkmann  at  6.2  oz. ;  but  these  amounts  are 
deduced  from  calculation  of  the  (supposed)  total  of  the  blood,  divided  by  the  estimated 
duration  of  its  passage  through  the  heart,  rather  than  from  actual  admeasurement. 

4  "Tiedemann's  Zeitschrift,"  vol.  iii.  p.  85. 

5  Although  attempts  have  been  made  to  invalidate  the  inference  which  seems  inevitably 
to  flow  from  these  experiments,  in  regard  to  the  rate  of  the  circulation,  by  attributing  the 
transmission  of  the  salt  to  the  permeability  of  the  animal  tissues,  yet  it  has  never  been 
shown  that  even  prussiate  of  potash  (which  is  probably  at  least  as  transmissible  through 
this  channel,  as  any  other  salt)  can  be  carried  from  one  part  to  another,  with  a  rapidity  at 
all  proportional  to  this ;  and  the  only  mode  in  which  this  property  can  be  conceived  mate- 
rially to  facilitate  the  transmission  of  the  salt  through  the  vascular  system,  would  be  by 
allowing  it  to  pass  through  the  septum  of  the  auricles,  and  thus  to  make  its  way  from  the 
right  to  the  left  side  of  the  heart,  without  passing  through  the  pulmonary  circulation ;  yet 
this  it  could  scarcely  do,  to  the  large  amount  which  is  evidently  transmitted,  in  so  short  a  time. 

e  "Ann.  des  Sci.  Nat.,"  1843,  Zool.,  torn,  xix.,  p.  32. 


ACTION    OF   THE    HEART.  479 

and  also  by  those  of  Mr.  Blake  j1  the  latter  of  whom  varied  them  by  employing 
different  substances,  and  took  other  precautions  against  sources  of  fallacy.  At 
an  interval  of  10  seconds  after  having  injected  a  solution  of  nitrate  of  baryta 
into  the  jugular  vein  of  a  horse,  he  drew  blood  from  the  carotid  artery  of  the 
opposite  side;  after  allowing  this  to  flow  for  5  seconds,  he  substituted  another 
vessel,  which  received  the  blood  that  flowed  during  the  5  ensuing  seconds ;  and 
the  blood  that  flowed  after  the  20th  second,  by  which  time  the  action  of  the 
Heart  had  stopped,  was  received  into  a  third  vessel.  These  different  specimens 
were  carefully  analyzed.  No  trace  of  Baryta  could  be  detected  in  the  blood, 
which  had  escaped  from  the  artery  between  the  tenth  and  the  fifteenth  second 
after  the  injection  of  the  poison;  but  in  that  which  was  drawn  between  the  fif- 
teenth and  the  twentieth  second,  the  salt  was  found  to  be  present,  and  in  greater 
abundance  than  in  the  blood  which  had  subsequently  flowed.  Moreover,  the 
coincidence  between  the  cessation  of  the  Heart's  action,  and  the  diffusion  of  the 
salt  through  the  arterial  blood,  bear  a  striking  correspondence ;  and  it  may  be 
hence  inferred,  that  the  arrestment  of  its  muscular  movement  is  due  to  the  effect 
of  this  agent  upon  its  tissue,  when  immediately  operating  upon  it,  through  the 
capillaries  of  the  coronary  artery.  This  conclusion  is  borne  out  by  a  variety  of 
other  experiments ;  which  show  that  the  time  of  the  agency  of  other  poisons  that 
suddenly  check  the  Heart's  action  (which  is  the  especial  property  of  mineral 
poisons)  nearly  coincides,  in  different  animals,  with  that  which  is  required  to 
convey  them  into  the  Arterial  capillaries.  And  it  seems  to  derive  full  con- 
firmation from  the  fact,  that  poisons,  which  act  locally  on  other  parts,  give  the 
first  indications  of  their  operation,  in  the  same  period  after  they  have  been  intro- 
duced into  the  Venous  circulation.  Thus,  in  the  Horse,  the  time  that  is  required 
for  the  blood  to  pass  from  the  Jugular  vein  into  the  capillary  terminations  of 
the  Coronary  arteries,  is  16  seconds  ;  as  is  shown  by  the  power  of  Nitrate  of 
Potass  to  arrest  the  Heart's  action  within  that  time :  and  Nitrate  of  Strychnia, 
injected  into  a  vein,  gave  the  first  manifestation  of  its  action  on  the  Spinal  Cord, 
in  precisely  the  same  number  of  seconds.  In  the  Dog,  the  Heart's  action  was 
arrested  by  the  Nitrate  of  Potass  in  11  or  12  seconds ;  and  the  tetanic  convul- 
sions occasioned  by  Strychnia,  also  commenced  in  12  seconds.  In  the  Fowl, 
the  former  period  was  6  seconds,  and  the  latter  6£;  in  the  Rabbit,  the  first  was 
4,  and  the  other  4?  seconds. — From  such  experiments,  it  seems  evident  that 
the  rapidity  of  the  Circulation  is  underrated,  in  any  estimate  that  we  found  upon 
the  capacity  of  the  Heart,  and  its  number  of  pulsations  in  a  given  time ;  and 
it  is  difficult  to  see  how  the  two  sets  of  facts  are  to  be  reconciled. 

510.  The/orce  with  which  the  systemic  Heart  propels  the  Blood,  may  be  esti- 
mated in  two  ways ; — either  by  ascertaining  the  height  of  the  column  of  that 
fluid  which  its  contractile  action  will  support,  or  by  causing  the  blood  to  act 
upon  a  shorter  column  of  mercury. — The  former  method  was  the  one  adopted  by 
Hales,  who  introduced  a  long  pipe  into  the  Carotid  artery  of  a  Horse,  and  found 
that  the  blood  would  sometimes  rise  in  it  to  the  height  of  10  feet.  From 
parallel  experiments  upon  Sheep,  Oxen,  Dogs,  and  other  animals,  and  by  com- 
paring the  caliber  of  their  respective  vessels  with  that  of  the  Human  aorta, 
Hales  concluded,  that  the  usual  force  of  the  Heart  in  Man  would  sustain  a 
column  of  blood  7?  feet  high,  the  weight  of  which  would  be  about  4  Ibs.  6  oz. — 
The  second  method  is  that  which  was  adopted  by  Poisseuille ;  the  result  of 
whose  experiments  (made  with  the  instrument  which  he  termed  the  "haemady- 
namorneter")  corresponded  very  closely  with  that  of  Hales,  his  estimate  of  the 
pressure  of  blood  in  the  aorta  being  4  Ibs.  3  oz.  [The  instrument  of  Poisseuille, 
slightly  modified  by  Volkmann,  consists  of  a  glass  tube  bent  so  as  to  form  a 
horizontal  (B")  and  two  perpendicular  (BB')  portions.  The  horizontal  portion 
is  capable  of  being  adapted  by  means  of  brass  tubes  of  various  size  to  arteries 

'   "Edinb.  Med.  and  Surg.  Journal,"  Oct.,  1841. 


480 


OF   THE   CIRCULATION   OF   THE   BLOOD. 


or  veins,  however  different  in  caliber.  The  tube  is  attached  to  a  board  (AA'), 
on  which  a  scale  is  marked.  To  use  it,  mercury  is  poured  into  the  perpen- 
dicular branches  of  the  tube,  and  will,  of  course,  stand  at  the  same  height  in 
each  when  the  instrument  is  kept  in  the  perpendicular. 

In  order  to  prevent  the  coagulation  of  the  blood,  which  by  causing  it  to 
adhere  to  the  sides  of  the  tube  would  complicate  the  experiment  (a  point  not 
provided  against  in  Hales' s  experiments)  a  quantity  of  a  strong  solution  of 
carbonate  of  soda  is  poured  into  the  horizontal  branch,  and  will,  therefore, 
rest  upon  the  column  of  mercury  in  the  nearest  vertical  branch. 

The  instrument  is  now  adapted  by  means  of  a  pipe  provided  with  a  stopcock 
(F)  to  the  artery  in  which  the  blood  is  to  be  measured.  On  opening  the  stop- 
cock the  blood  rushes  into  the  horizontal  tube,  mingles  with  the  alkaline  solu- 
tion, and  pushes  down  the  mercury,  in  the  vertical  tube  B',  that  in  the  tube  B 

Fig.  140. 


Poisseuille's  Hsemadynamometer,  as  slightly  modified  by  Volkmann :— AA',  the  board  to  which  the  bent 
glass  tube  (BB'B")  is  attached.  C'C",  a  tin  tube  which  is  fixed  through  a  cork  (D),  air-tight  to  the  horizontal 
branch  of  the  glass  tube.  E,  an  opening  with  a  stopcock  in  this  tube.  F,  a  conical  tube  which  may  be  intro- 
duced into  an  artery  or  vein.  This  is  provided  with  a  stopcock,  which  serves  to  regulate  the  admission  of  the 
blood  into  the  tube  of  the  haemadynamometer.  GHG',  an  arm  of  wood  connected  with  the  board  which 
serves  to  support  the  tin  tube,  and  so  protect  the  horizontal  branch  of  the  glass  tube. 

rising  to  the  same  extent  as  the  first  is  depressed.  The  rise  and  fall  of  the 
mercury  in  each  vertical  branch  can  be  measured  on  scales  placed  behind  them, 
and  as  the  rise  and  fall  are  equal,  the  double  of  either  will  give  the  height  of 
a  column  of  mercury  which  the  force  of  the  stream  of  blood  is  able  to  main- 
tain. By  causing  the  blood  to  press  upon  a  column  of  mercury,  Poisseuille 
got  rid  of  the  necessity  of  having  a  very  long  tube,  as  used  by  Hales. — ED.] 


ACTION    OF   THE    HEART.  481 

The  more  recent  experiments  of  Yolkmann1  have  led  him  to  nearly  the  same 
conclusion;  notwithstanding  that  he  has  pointed  out  certain  fallacies  in  Pois- 
seuille's  method.  The  force  which  the  walls  of  the  Heart  must  exert,  in  order 
to  impart  such  a  pressure  to  the  blood  which  they  propel,  is  properly  estimated 
by  multiplying  the  pressure  of  blood  in  the  aorta  by  the  ratio  between  the  area 
of  that  trunk  and  the  surface  of  a  plane  passing  through  the  base  and  apex  of 
the  left  ventricle ;  which  method  of  computation  would  make  it  about  13  Ibs. 

511.  The  number  of  contractions  of  the  Heart  in  a  given  time  is  liable  to 
great  variation,  within  the  limits  of  ordinary  health,  from  several  causes ;  the 
chief  of  these  are  diversities  of  Age,  of  Sex,  of  Stature,  of  Muscular  exertion,  of 
the  condition  of  the  Mind,  of  the  state  of  the  Digestive  system,  and  of  the  Period 
of  the  day. 

a.  Putting  aside  the  other  causes  of  uncertainty,  the  following  table  may 
be  regarded  as  an  approximation  to  the  average  frequency  of  the  Pulse  at 
the  several  Ages  specified  in  it,  taking  equal  numbers  of  Males  and  Females. 

BEATS  PER  MINUTE. 

In  the  foetus  in  utero   .  140  — 150 


Newly-born  infant        .         . 
During  the  1st  year     .     - •[•  ..<• 
During  the  2d  year 
During  the  3d  year 
From  the  7th  to  the  14th  year 
From  the  14th  to  the  21st  year 
From  the  21st  to  the  60th  year 
Old  age2       .    n  tv  •; V  . 


130—140 

115  —  130 

100  —  115 

95  —  105 

80—  90 

75—  85 

•70—  75 

75—  80 


l>.  The  difference  caused  by.  Sex  is  very  considerable,  especially  in  adult  age; 
it  appears  from  the  inquiries  of  Dr.  Guy,3  that  the  pulse  of  the  adult  Female 
exceeds  in  frequency  the  pulse  of  the  adult  Male,  at  the  same  mean  age,  by  from 
10  to  14  beats  in  a  minute. 

c.  Many  of  the  observations  upon  the  effect  of  Stature  upon  the  pulse  are 
invalidated  by  the  neglect  of  other  conditions  in  making  them ;  it  is  affirmed  by 
Volkmann,  however,  that  a  tolerably  definite  ratio  exists,4  the  pulse  being,  caeteris 
paribuSy  less  frequent  as  the  stature  is  greater,  so  that  if  the  pulse  of  a  man  of 
5J  feet  high  were  70  per  minute,  that  of  a  man  of  6  feet  would  be  66.7,  and 
that  of  a  man  of  5  feet,  73.8. 

d.  The  effect  of  Muscular  Exertion  in  raising  the  pulse  is  well  known;  as  is 
also  the  fact  which  is  one  exemplification  of  it,  that  the  pulse  varies  considerably 
with  the  posture  of  the  body.     The  amount  of  this  variation  has  been  made  the 
subject  of  extensive  inquiry  by  Dr.  Gruy  ;  and  the  following  are  his  results.     In 
100  healthy  Males,  of  the  mean  age  of  27  years,  in  a  state  of  rest,  the  average 
frequency  of  the  pulse  was,  when  standing  79,  when  sitting  70,  and  when  lying 
67  per  minute.     Several  exceptions  occurred,  however,  to  the  general  law;  and 
when  these  were  excluded,  the  average  numbers  were,  standing  81,  sitting  71, 
and  lying  66 ;  so  that  the  difference  between  standing  and  sitting  was  10  beats, 
or  l-8th  of  the  whole;  the  difference  between  sitting  and  lying  was  5  beats,  or 

1  "Die  Hamodynamik  nach  Versuchen,"  CHAP.  vn. 

2  The  rise  in  the  average  frequency  of  the  pulse  in  very  advanced  life,  contrary  to  the 
prevalent  notion,  has  been,  determined  by  the  observations  of  Leuret  and  Mitivi6  ("  De  la 
Frequence  des  Pouls  chez  les  Alienes"),  Dr.  Pennock  ("  Amer.  Journ.  of  Med.  Sci.,"  July, 
1847),  and  Prof.  Volkmann  (Op.  cit.,  p.  427). 

3  "Guy's  Hospital  Reports,"  vol.  iii.  p.  312;  and  "Cyclop,  of  Anat.  and  Physiol.," 
Art.  "Pulse." 

4  With  his  usual  zeal  for  formularization,  Volkmann  expresses  this  ratio,  as  deduced  from 
a  large  number  of  observations,  by  the  ratio p :  pf=h^  :  A| ; — p  being  the  rate  of  the  pulse, 
and  h  the  height  of  the  body.     Or.  in  other  words,  the  ratio  is  that  of  the  ninth  root  of  the 
fifth  power  of  the  height.     Surely  mis  is  riding  a  hobby  to  the  death. 

31 


482  OF   THE   CIRCULATION    OF   THE   BLOOD. 

l-13th  of  the  whole  ;  and  the  difference  between  standing  and  lying  was  15  beats, 
or  l-5th  of  the  whole.  In  50  healthy  Females,  of  the  same  mean  age,  the 
average  pulse  when  standing  was  89,  when  sitting  81,  and  when  lying  80 ;  and 
when  the  exceptions  (which  were  more  numerous  in  proportion  than  in  males) 
were  excluded,  the  averages  were,  standing  91,  sitting  84,  lying  79 ;  the  differ- 
ence between  standing  and  sitting  was  thus  7  beats,  or  l-13th  of  the  whole  :  that 
between  sitting  and  lying  was  4,  or  l-21st  of  the  whole ;  and  that  between  stand- 
ing and  lying  was  11,  or  l-8th  of  the  whole.  In  both  sexes,  the  effect  produced 
by  change  of  posture  increases  with  the  usual  frequency  of  the  pulse  ;  whilst  the 
exceptions  to  the  general  rule  are  more  numerous,  as  the  pulse  is  less  frequent. 
The  variation  is  temporarily  increased  by  the  muscular  effort,  involved  in  the 
absolute  change  of  the  posture ;  and  it  is  only  by  the  use  of  a  revolving  board, 
by  which  the  position  of  the  body  can  be  altered,  without  any  exertion  on  the 
part  of  the  subject  of  the  observation,  that  correct  results  can  be  obtained.  That 
the  difference  between  standing  and  sitting  should  be  greater  than  that  between 
sitting  and  lying,  is  just  what  we  should  expect ;  when  we  compare  the  amount 
of  muscular  effort  required  in  the  maintenance  of  the  two  former  positions  re- 
spectively. 

e.  The  pulse  is  well  known  to  be  much  accelerated  by  Mental  excitement, 
especially  by  that  of  the  Emotions ;  it  is  also  quicker  during  Digestion ;  but  on 
neither  of  these  points  can  any  exact  numerical  statement  be  given. 

f.  The  diurnal  variation  of  the  Pulse  has  been  made  the  subject  of  observation 
by  Dr.  Knox1  and  Dr.  Guy  ;3  whose  inquiries  concur  to  disprove  the  usual  notion 
that  the  pulse  rises  towards  evening,  and  make  it  appear  that  the  more  common 
fact  is  the  reverse.     It  should  not  be  laid  down  as  a  general  rule,  however,  that 
the  pulse  is  most  frequent  in  the  morning,  unless  it  be  also  stated  that  the  exceptions 
are  very  numerous.     For,  whilst  out  of  sixteen  healthy,  young  persons  of  both 
sexes  examined  by  Dr.  Guy,  the  pulse  was  more  frequent  in  the  morning  in  ten 
individuals  by  from  2  to  18  beats  per  minute,  it  was  more  frequent  in  the  evening 
in  four  individuals  by  from  9  to  13  beats,  and  in  two  others  there  was  no  differ- 
ence.    Both  these  experimenters  have  remarked,  moreover,  that  the  pulse  is  less 
excitable,  as  well  as  less  frequent,  in  the  evening  than  in  the  morning ;  thus,  it 
was  found  by  Dr.  Guy  that  the  very  same  food  which  in  the  morning  increased 
the  frequency  of  the  pulse  from  5  to  12  beats,  and  kept  it  raised  above  its  natural 
number  for  one  or  two  hours,  produced  no  effect  whatever  in  the  evening ;  and 
it  is  a  matter  of  ordinary  experience  that  alcoholic  liquors  have  a  much  more 
potent  effect  upon  the  circulation  in  the  earlier  than  in  the  latter  part  of  the 
day. 

3. — Movement  of  the  Blood  in  the  Arteries. 

512.  The  Blood  propelled  from  the  Heart  is  distributed  to  the  body  in  general 
by  a  system  of  Arteries,  which  may  be  likened  in  its  arrangement  to  the  trunk 
and  branches  of  a  tree,  except  that  very  frequent  communications  or  anasto- 
moses exist  among  these  branches,  so  that,  by  continual  subdivision  and  inoscu- 
lation, their  distribution  comes  more  and  more  to  resemble  the  capillary  network 
in  which  they  terminate  (Fig.  141).  Although  the  diameters  of  the  branches, 
at  each  subdivision,  together  exceed  that  of  the  trunk,  yet  there  is  but  little 
difference  in  their  respective  areas.  What  difference  does  exist,  however,  is 
usually  in  favor  of  the  branches ;  and  thus  it  happens  that  there  is  a  gradual 
increase  in  the  capacity  of  the  arterial  system  from  its  centre  towards  the  capil- 
laries, whose  capacity  is  many  times  greater  (§  529). — The  Arteries  exert  a 

1  "Edinb.  Med.  and  Surg.  Journ.,"  vol.  xi.  p.  53. 

2  "  Guy's  Hosp.  Rep.,"  vol.  iv.  p.  6(£ 


MOVEMENT    OF    THE   BLOOD    IN    THE    ARTERIES. 


483 


most  important  influence  upon  the  movement  of  blood  through  them,  in  virtue 
of  the  physical  and  vital  properties  of  their  walls,  or  rather  of  their  middle  or 

Fig.  141. 


Web  of  Frog' 's  foot,  stretching  between  two  toes,  magnified  3  diameters ;  showing  the  bloodvessels 
and  their  anastomoses :  1, 1,  veins ;  2, 2,  2,  arteries. 

fibrous  coat,  wflich  alone  is  possessed  of  contractile  properties.  We  find  in  this 
coat  a  layer  of  annular  fibres,  composed  of  muscular  fibre  cells,  mingled  with 
areolar  tissue.1  On  the  outside  of  this,  is  a  layer  of  yellow  elastic  tissue,  which 
is  much  thicker  in  the  larger  arteries,  in  proportion  to  their  size,  than  in  the 
smaller.  To  this  last  tissue  is  due  the  simple  elasticity  of  the  arterial  walls, 
which  is  a  physical  property  that  persists  after  death,  until  a  serious  change 
takes  place  in  their  composition;  whilst  to  the  one  first  mentioned,  we  are  to 
attribute  the  property  which  they  unquestionably  possess  (in  common  with  proper 
muscular  tissue)  of  contracting  on  the  application  of  a  stimulus,  so  long  as  their 
vitality  remains.  These  two  endowments  are  possessed  in  various  proportional 
degrees,  by  the  different  parts  of  the  Arterial  system.  Thus,  it  was  justly  re- 
marked by  Hunter,  that  elasticity,  being  the  property  by  which  the  interrupted 
force  of  the  Heart  is  made  equable  and  continuous,  is  most  seen  in  the  large 
vessels  more  immediately  connected  with  that  organ ;  whilst  on  the  other  hand, 
the  contractility  is  most  observable  in  the  smaller  vessels,  where  it  is  more 
required  for  regulating  the  flow  of  blood  towards  particular  organs. 

513.  It  has  been  denied  by  many  Physiologists,  that  the  middle  coat  of  the 
Arteries  possesses  any  property  that  can  be  likened  to  muscular  Irritability  ; 
but  no  reasonable  doubt  can  any  longer  exist  on  this  point.  That  the  walls  of 
arteries  cannot  be  readily  stimulated  to  contraction  through  the  medium  of  their 
nerves  is  universally  admitted ;  but  the  same  is  the  case  with  regard  to  the 
muscular  coat  of  the  Alimentary  canal  which  contracts  most  vigorously  on  the 
direct  application  of  stimuli  to  itself;  and  Valentin  and  others  have  succeeded 
in  producing  evident  contractions  in  the  Aorta,  by  irritation  of  the  Sympathetic 
nerve,  and  of  the  roots  of  the  cervical  nerves  of  the  Spinal  system.  Further, 
although  many  experimenters  have  failed  in  producing  contractions  of  this  tissue 
by  stimuli  directly  applied  to  itself,  yet  such  contractions  may  be  so  easily 

1  Kolliker,  in  "Kolliker  and  Siebold's  Zeitschrift,"  1849. 


484  OF   THE   CIRCULATION    OF    THE   BLOOD. 

demonstrated  by  proper  means,  that  the  negative  results  cannot  be  admitted  as 
invalidating  the  fact.  It  is  of  course  in  the  smaller  arteries,  that  the  evidence 
of  this  contractility  should  be  sought ;  and  this  may  be  readily  obtained  by 
observing  the  effects  of  various  stimuli,  mechanical,  chemical,  or  electrical,  upon 
the  vessels  of  a  transparent  membrane,  such  as  the  bat's  wing  or  the  frog's  foot. 
Thus  if,  whilst  we  watch  the  movement  of  blood  in  a  companion  artery  and  vein, 
we  draw  the  point  of  a  fine  needle  across  them  three  or  four  times,  without 
apparently  injuring  them  or  the  membrane  over  them,  they  will  both  presently 
contract  and  close ;  then  after  remaining  for  a  few  minutes  in  the  contracted 
state,  they  will  begin  again  to  dilate,  and  will  gradually  increase  in  diameter 
until  they  acquire  a  larger  size  than  before  the  stimulus  was  applied.  When  in 
this  condition,  they  will  not  again  contract  on  the  same  stimulus  as  before ;  the 
needle  may  now  be  drawn  across  them  much  oftener  and  more  forcibly,  but  no 
contraction  ensues,  or  only  a  trivial  one  which  is  quickly  followed  by  dilatation ; 
with  a  stronger  stimulus,  however,  such  as  that  of  great  heat,  they  will  again 
contract  and  close,  and  such  contraction  may  last  more  than  a  day  before  the 
vessels  again  open  and  permit  the  flow  of  blood  through  them.1 — The  compara- 
tive effects  of  chemical  and  other  stimuli  have  recently  been  especially  studied 
by  Mr.  Wharton  Jones,3  by  whom  they  are  thus  classified.  (1.)  Constriction 
may  slowly  take  place,  and  be  slowly  succeeded  by  the  normal  width ;  this  is 
the  action  of  the  sulphate  of  atropia.  (2.)  Constriction  may  quickly  take 
place,  and  be  soon  succeeded  by  the  normal  width,  or  a  width  not  much  exceed- 
ing the  normal ;  this  is  the  result  of  the  moderate  application  of  cold,  and  of 
mechanical  and  galvanic  irritation.  (3.)  Constriction  either  does  not  take  place 
at  all,  or  when  it  does,  it  very  rapidly  gives  place  to  great  dilatation;  this  is  the 
effect  of  a  weak  solution  of  sulphate  of  copper,  of  a  strong  solution  of  common 
salt,  of  wine,  of  opium,  and  of  spirit  of  wine.  (4.)  Dilatation,  preceded  or 
not  by  momentary  constriction,  may  slowly  yield  to  constriction,  which  remains 
permanent ;  this  is  the  effect  of  sulphate  of  copper,  applied  in  strong  solution, 
or  in  substance. — The  electric  stimulus  is  most  effectual  when  applied  by  the 
magneto-galvanic  apparatus ;  and  the  effects  of  such  application  have  been  espe- 
cially studied  by  the  Professors  Weber.3  When  the  minute  arteries  of  the  mesen- 
tery of  frogs  between  1-7 th  and  l-17th  of  a  Paris  line  in  diameter,  were  thus 
stimulated,  they  did  not  immediately  respond  to  the  irritation,  but  began  to 
contract  after  a  few  seconds,  so  that  their  diameter,  in  from  five  to  ten  seconds, 
was  diminished  by  a  third,  and  their  sectional  area  consequently  reduced  to  about 
half ;  by  a  continued  application  of  the  stimulus  their  caliber  was  so  much  re- 
duced that  only  a  single  row  of  corpuscles  could  pass ;  and  at  last  the  vessels 
became  completely  closed,  and  the  current  of  blood  arrested,  the  original  condi- 
tions being  gradually  restored  on  the  cessation  of  the  electric  current. — Further, 
it  has  been  ascertained  by  the  careful  experiments  of  Poisseuille  (which  confirm 
those  of  John  Hunter)  that  when  an  artery  is  dilated  by  fluid  injected  into  it, 
it  reacts  with  a  force  superior  to  the  distending  impulse ;  and  he  has  also  shown 
that,  if  a  portion  of  an  artery  from  an  animal  recently  dead  (in  which  the  vital 
contractility  seems  to  be  preserved),  and  one  from  an  animal  that  has  been  dead 

1  See  Mr.  Paget's  "Lectures  on  Inflammation,"  in  "Medical  Gazette,"  June  7,  1850. — 
As  Mr.  Paget  justly  remarks,  it  is  from  the  mechanical  stimulus  of  the  knife  that  small 
divided  vessels  contract  and  close,  so  as  speedily  to  cease  bleeding ;  but  this  contraction 
lasts  only  for  a  time ;    and  hemorrhage  would  commence  on  their  dilatation,  if  their 
mouths  were  not  sealed  by  coagula  of  blood  or  lymph.     When  secondary  hemorrhage 
does  occur  from  want  of  such  coagulation,  it  is  most  effectually  controlled  by  the  applica- 
tion of  stimuli  which,  like  the  actual  cautery,  induce  a  more  prolonged  contraction  of  the 
vessels. 

2  "Prize  Essay  on  Inflammation,"  in  "  Guy's  Hospital  Reports"  for  1850,  pp.  8,  9. 

3  "  Muller's  Archiv.,"  1847. 


MOVEMENT   OF   THE   BLOOD   IN   THE   ARTERIES.  485 

some  days  (in  which  nothing  but  the  elasticity  remains),  be  distended  with  an 
equal  force,  the  former  becomes  much  more  contracted  than  the  latter,  after  the 
distending  force  is  removed. 

514.  Several  experiments  also  indicate  the  existence  of  that  power  of  slow 
contraction  in  the  arteries,  which  has  been  distinguished  by  the  appellation 
Tonicity  (§  331).     Thus,  when  a  ligature  is  placed  upon  an  artery  in  a  living 
animal,  the  part  of  the  artery  beyond  the  ligature  becomes  gradually  smaller, 
and  is  emptied  to  a  certain  degree,  if  not  completely,  of  the  blood  it  contained. 
Again,  when  part  of  an  artery  in  a  living  animal  is  isolated  by  means  of  two 
ligatures,  and  is  punctured,  the  blood  issues  from  the  orifice,  and  the  inclosed 
portion  of  the  artery  is  almost  completely  emptied  of  its  contents.     Further, 
every  Surgeon  knows,  that  the  contraction  of  divided  arteries  is  an  efficient  means 
of  the  arrest  of  hemorrhage  from  them,  especially  when  they  are  of  small  caliber  ; 
so  that,  in  the  case  of  the  temporal  artery  for  example,  the  complete  division  of 
the  tube  is  often  the  readiest  means  of  checking  the  flow  of  blood  from  it,  when 
it  has  been  once  wounded.     This  contraction  is  much  greater  than  could  be 
accounted  for  by  the  simple  elasticity  of  the  tissue ;  and  is  more  decided  in  small, 
than  in  large  vessels.     The  empty  condition  of  the  arteries,  generally  found 
within  a  short  time  after  death,  seems  to  be  in  part  due  to  the  same  cause ; 
since  their  caliber  is  usually  much  diminished,  and  is  sometimes  completely 
obliterated.     A  remarkable  example  of  the  same  slow  contraction  is  that  which 
takes  place  in  the  end  of  the  upper  portion  of  an  arterial  trunk,  when  the 
passage  of  blood  through  it  is  interrupted  by  a  ligature;  for  the  current  of  blood 
then  passes  off  by  the  nearest  large  lateral  branch;  and  the  tube  of  the  artery 
shrivels,  and  soon  becomes  impervious,  from  the  point  at  which  the  ligature  is 
applied,  back  to  the  origin  of  that  branch.     This  last  fact  is  important,  as  proving 
how  little  influence  the  vis  a  tergo  possesses  over  the  caliber  of  arterial  tubes ; 
since,  without  any  interruption  to  the  pressure  of  blood  occasioned  by  it,  the 
tube  becomes  impervious.     It  is  to  the  moderate  action  of  the  tonicity  of  arteries, 
that  their  contraction  upon  the  stream  of  blood  passing  through  them  (which 
serves  to  keep  the  tubes  always  full)  is  due.     If  the  tonicity  be  excessive,  the 
pulse  is  hard  and  wiry ;  but  if  it  be  deficient,  the  pulse  is  very  compressible, 
though  bounding,  and  the  flow  of  blood  through  the  arteries  is  retarded.     Dr. 
C.  J.  B.  Williams  has  performed  some  ingenious  experiments  (§  532),  which 
prove  that  the  force  required  to  propel  fluid  through  a  tube  whose  sides  are 
yielding,  is  very  much  greater  than  that  which  will  carry  it  through  a  tube  of 
even  smaller  size,  with  rigid  parietes;  consequently,  a  loss  of  tonicity  in  the 
bloodvessels  retards  the  flow  of  blood  through  them ;  whilst  an  increase  hastens 
it. — We  have  seen  that  between  the  Irritability  of  arteries  and  their  Tonicity, 
there  is  much  less  difference  than  exists  in  most  other  muscular  structures; 
since  the  former  is  so  long  in  manifesting  itself,  that  it  almost  approaches  to  the 
character  of  the  latter.     But  in  the  Arteries,  as  in  other  muscles,  the  tonic 
contraction  may  be  most  efficiently  induced  by  cold.     Thus  Hunter  observed 
that  the  exposure  of  an  artery  of  a  warm-blooded  animal  to  the  air  for  some  time, 
would  occasion  its  gradual  contraction  to  such  an  extent  as  to  effect  the  ob- 
literation of  its  canal.     This  statement  has  been  verified  by  many  subsequent 
experimenters;  and  it  has  also  been  confirmed  by  the  observations  of  Schwann 
upon  the  small  arteries  of  the  mesentery  of  frogs,  which  he  caused  to  contract 
slowly  by  the  application  of  cold  water,  and  then  saw  dilate  again ;  as  much  as 
half  an  hour  being  required,  however,  before  they  recovered  their  original  size. 
On  the  other  hand,  the  application  of  moderate  warmth  causes  a  relaxation  of 
this  tonic  contraction. — And  thus  Cold  and  Heat  are  two  of  our  most  valuable 
remedial  agents,  when  the  Tonicity  of  the  Vascular  system  is  deficient  or  in 
excess. 

515.  We  have  now  to  inquire  more  closely  into  the  influence  exerted  by  the 


486  OF   THE   CIRCULATION   OF   THE   BLOOD. 

vital  and  physical  properties  of  the  walls  of  the  Arteries,  upon  the  motion  of 
Blood  through  them. — There  is  no  sufficient  proof  that  the  vital  Contractility  of 
these  vessels  enables  them  to  exert  a  propulsive  action  in  any  degree  supplement- 
ary to  that  of  the  Heart ;  and  yet,  looking  to  the  general  facts  already  stated, 
as  to  the  diffusion  of  the  propulsive  power  through  the  arterial  trunks  in  many 
of  the  lower  animals  (§  493),  and  their  experimentally-proved  reaction  upon  a 
distending  force,  it  does  not  seem  by  any  means  improbable  that  some  such 
power  should  be  preserved,  even  where  there  is  the  greatest  concentration  of  the 
propulsive  force  in  the  muscular  walls  of  the  heart. — The  contractility  of  the 
arteries  seems  to  be  chiefly  exercised,  however,  in  regulating  the  diameter  of  the 
tubes,  in  accordance  with  the  quantity  of  blood  to  be  conducted  through  them 
to  any  part;  which  will  depend  upon  its  peculiar  circumstances  at  the  time. 
Such  local  changes  are  continually  to  be  observed,  in  the  various  phases  of  nor- 
mal life,  as  well  as  in  diseased  states ;  and  they  will  be  found  to  be  constantly 
in  harmony  with  the  particular  condition  of  the  processes  of  Nutrition,  Secretion, 
&c.,  to  which  the  capillary  circulation  ministers.  In  such  cases,  it  cannot  be  the 
action  of  the  Heart  that  increases  the  caliber  of  the  vessels;  since  this  is  com- 
monly unaltered,  and  is  itself  unable,  as  we  have  just  seen,  even  to  maintain 
their  permeability,  when  their  contractility  is  excited.  It  must,  therefore,  be 
by  a  power  operating  directly  through  themselves,  that  their  dilatation  is  ef- 
fected. The  minute  distribution  of  the  Sympathetic  nerve  upon  the  walls  of 
the  arteries,  the  known  power  which  this  has  of  producing  contractions  in  their 
fibrous  coat  (§  513),  and  the  influence  of  mental  states  upon  their  dimensions 
(as  shown  in  the  phenomena  of  blushing  and  erection),  render  it  highly  probable 
that  the  caliber  of  the  arteries  is  regulated  in  no  inconsiderable  degree  through 
its  intervention.  The  permanent  dilatation,  however,  which  is  seen  in  the 
arteries  supplying  parts  that  are  undergoing  enlargement,  must  be  due,  not  to 
simple  dilatation  merely,  but  to  increased  nutrition;  since  we  find  that  their 
walls  are  thickened  as  well  as  extended.  And,  on  the  other  side,  when  slow 
contraction  occurs  in  these  tubes,  as  a  consequence  of  disease,  it  must  be  in  part 
occasioned  by  atrophy;  since  their  nutrition  is  so  much  diminished,  that  in 
time  they  almost  entirely  disappear — a  portion  of  a  large  artery  occasionally 
shrivelling  into  a  ligamentous  band. 

516.  The  purpose  served  by  the  Elasticity  of  the  Arteries  is  one  of  a  purely 
physical  character;  its  effect  being  to  convert  the  intermitting  impulses  which 
the  blood  receives  from  the  heart,  into  a  continuous  current.  The  former  are 
very  evident  in  the  larger  trunks;  but  they  diminish  with  the  subdivision  of 
these,  until  they  entirely  disappear  in  the  capillaries,  in  which  the  stream  is 
usually  equable  or  nearly  so.  If  a  powerful  force-pump  were  made  to  inject 
water,  by  successive  strokes,  into  a  system  of  tubes  with  unyielding  walls,  the 
flow  of  fluid  at  the  farther  extremities  of  these  tubes  would  be  as  much  inter- 
rupted as  its  entrance  into  them.  But  if  an  air-vessel  (like  that  of  a  fire-engine) 
were  placed  at  their  commencement,  the  flow  would  be  in  a  great  degree  equal- 
ized ;  since  a  part  of  the  force  of  each  stroke  would  be  spent  upon  the  compres- 
sion of  the  air  included  in  it ;  and  this  force  would  be  restored  by  the  elasticity 
of  the  air  during  the  interval,  which  would  propel  the  stream,  until  directly 
renewed  by  the  next  impulse.  A  much  closer  imitation  of  the  natural  apparatus 
would  be  afforded  by  a  pipe  which  had  elastic  walls  of  its  own ;  thus  if  water 
were  forced  by  a  syringe  into  a  long  tube  of  caoutchouc,  for  example,  the  stream 
would  be  equalized  before  it  had  proceeded  far.  This  effect  is  found  to  be  accom- 
plished, at  any  point  of  the  arterial  circulation,  in  a  degree  proportionate  to  its 
distance  from  the  Heart ;  and  in  this  mode  it  is  that  the  intermitting  force 
of  the  ventricular  contraction  is  almost  equably  distributed  over  the  whole  of 
the  interval  between  one  systole  and  another,  by  the  contraction  of  the  elastic 
tubes  in  the  dilatation  of  which  it  was  at  first  expended. — Another  effect  of  this 


MOVEMENT    OP   THE   BLOOD   IN   THE  ARTERIES.  487 

elasticity  is  to  distribute  the  pressure  of  the  blood  upon  the  walls  of  the  arteries, 
much  more  equally  than  would  be  the  case  if  they  formed  a  system  of  rigid 
tubes.  For,  according  to  Volkmann,1  since  the  lateral  pressure  of  a  liquid 
moving  through  tubes  of  uniform  caliber  with  rigid  walls,  is  proportional  to  the 
resistance  to  be  overcome  at  each  point,  and  since  this  resistance  depends  upon 
the  adhesion  and  friction  between  the  liquid  and  the  parietes  of  the  tube,  the 
lateral  pressure  at  each  point  will  vary  inversely  with  the  distance  of  that  point 
from  the  discharging  orifice.  Consequently,  if  the  arteries  constituted  a  system 
of  rigid  tubes,  the  pressure  on  their  walls  would  decrease  very  rapidly  in  passing 
from  the  heart  towards  their  peripheral  extremities.  Such,  however,  is  far  from 
being  the  case  (§  519). 

517.  The  distension  of  the  Arteries  consequent  upon  the  intermittent  injec- 
tion of  blood  into  their  trunks,  and  the  subsequent  contraction  which  results  from 
the  elasticity  of  their  walls,  give  rise  to  the  pulsation  which  is  perceptible  to  the 
touch  in  all  but  the  smallest  arteries,  and  is  visible  to  the  eye  when  they  are 
exposed.  This  pulsation  involves  an  augmentation  of  the  capacity  of  that  por- 
tion of  the  artery  in  which  it  is  observed;  and  it  would  seem  to  the  touch  as  if 
this  were  chiefly  effected  by  an  increase  of  diameter.  It  seems  fully  proved, 
however,  that  the  increased  capacity  is  chiefly  given  by  the  elongation  of  the 
artery,  which  is  lifted  from  its  bed  at  each  pulsation,  and,  when  previously 
straight,  becomes  curved;  the  impression  made  upon  the  finger  by  such  displace- 
ment not  being  distinguishable  from  that  which  would  result  from  the  dilatation 
of  the  tube  in  diameter.  A  very  obvious  example  of  this  upheaval  is  seen  in 
the  prominent  temporal  artery  of  an  old  person.  The  total  increase  of  capacity 
was  estimated  by  Flourens,  from  experiments  upon  the  carotid  artery,  at  about 
l-23d  part;  but  it  is  affirmed  by  Volkmann  (Op.  cit.,  xiv.)  that  this  must  not 
be  considered  by  any  means  a  constant  ratio,  since  it  varies  in  different  arteries 
and  in  the  same  artery  under  different  circumstances.3 — The  distension  of  the 
arteries  does  not  take  place  at  the  same  moment  over  the  whole  body,  but  is 
propagated  as  a  wave  from  the  commencement  to  the  point  of  discharge.  The 
passage  of  this  wave  was  considered  by  Prof.  E.  H.  Weber  to  be  distinct  from 
the  act  of  propulsion  of  the  fluid;  but  it  has  been  shown  by  Volkmann  (Op. 
cit.,  chap,  x.)  that  they  are  one  and  the  same.  He  has  further  shown  that  two 
systems  of  waves  arise,  when  a  fluid  is  driven  through  an  elastic  tube  by  inter- 
mitting impulses;  one  of  these  being  in  the  fluid,  and  the  other  in  the  walls  of 
the  tube.  These  may  propagate  themselves  with  different  velocities,  and  thus 
two  undulations  may  result  from  one  impulse.  This  want  of  coincidence  be- 
tween the  two  waves  is  probably  the  explanation  of  the  dichrotous  pulse,  often 
observable  in  convalescence  from  fevers  and  other  diseases  after  the  subsidence 
of  vascular  excitement. — That  a  certain  time  is  required  for  the  transmission  of 
the  pulse-wave  from  the  heart  to  the  periphery  of  the  circulation,  is  proved  by 
the  want  of  synchronism  between  the  ventricular  systole  and  the  pulsation  of 
the  arteries  in  various  parts  of  the  body,  the  difference  varying  according  to  their 
distance  from  the  heart.  A  considerable  diversity  in  the  amount  of  this  interval 

1  "Hamodynamik,"  p.  38. 

2  The  experiments  of  Volkmann  have  led  him  to  believe  that  the  transverse  dilatation 
is  greater  than  the  longitudinal ;   but  these  experiments  were  made  under  conditions  so 
different  from  those  of  the  living  artery,  that  but  little  weight  can,  in  the  Author's  opinion, 
be  attached  to  them.     It  is  to  be  remembered,  however,  that  every  increase  in  length 
augments  the  capacity  only  in  a  simple  ratio ;  thus  a  tube  of  21  inches  in  length  will  only 
contain  one-twentieth  more  than  a  tube  of  twenty  inches  long,  of  the  same  diameter.     On 
the  other  hand,  every  increase  in  diameter  augments  the  capacity  of  the  tube  in  the  ratio 
of  the  square  of  that  increase;  thus  the  capacity  of  a  tube  of  21  lines  in  diameter  will  be 
to  that  of  a  tube  of  20  lines  as  441 :  400,  or  one-tenth  more.     Consequently,  supposing  the 
increase  of  capacity  to  take  place  equally  in  both  directions,  the  increase  in  longitudinal 
dimension  will  be  far  more  apparent  than  the  transverse  enlargement. 


488  OF   THE   CIRCULATION   OF   THE   BLOOD. 

is  observable  in  different  states  of  the  arterial  system;  for,  as  Dr.  C.  J.  B. 
Williams  has  pointed  out,1  when  the  tonicity  is  in  excess,  the  arteries  approach 
the  condition  of  rigid  tubes,  and  the  pulse  at  the  wrist  is  almost  exactly  syn- 
chronous with  the  heart's  beat;  whilst,  if  the  tonicity  be  defective,  the  radial 
pulse  is  felt  at  a  long  interval  after  the  heart's  beat,  and  the  difference  is  still 
more  perceptible  when  the  pulse  is  examined  in  the  feet.  The  longest  interval 
in  a  state  of  health  seems  to  be  between  l-6th  and  l-7th  of  a  second. 

518.  The  rate  of  movement  of  the  blood  in  the  Arteries  can  only  be  guessed- 
at,  as  regards  the  Human  subject,  from  the  comparative  results  of  experiments 
upon  the  lower  animals.  It  is  stated  by  Volkmann  (Op.  cit.,  p.  196)  that  the 
average  velocity  of  the  current  in  the  carotids  of  a  considerable  number  of 
Mammals  which  he  examined,  was  about  300  millim.,  or  nearly  12  inches,  per 
second;  that  the  velocity  is  greater  in  the  arteries  lying  near,  than  in  those  at  a 
distance  from  the  heart;  that  it  is  not  increased  by  an  augmentation  in  the  num- 
ber of  pulsations  ;3  but  that  it  is  greatly  augmented  by  an  increase  in  the  volume 
of  the  blood,  and  lessened  by  its  diminution.  [The  instrument  devised  by 
Volkmann,  and  which  he  calls  the  haemodrometer,  consists  of  a  glass  tube,  fifty- 
two  inches  long,  bent  into  the  form  of  a  hair-pin,  and  containing  water,  which  is 
substituted  for  a  segment  of  the  bloodvessel,  in  which  it  is  required  to  measure 
the  velocity  of  the  blood's  stream.  The  column  of  blood  which  comes  from 
the  heart  pushes  the  column  of  water  before  it,  without  any  great  mixture  of 
the  two  fluids  taking  place,  and  in  passing  through  a  determined  space  it  takes 
a  measurable  time,  whence  it  may  be  calculated  how  far  the  blood  moves  in  a 
second. 

The  following  description  will  explain  the  instrument  and  the  mode  of  using 
it.  At  A  (Fig.  141*)  is  a  metal  tube,  an  inch  and  a  half  in  length ;  the  ends  of 
this  (a  a')  are  conical,  and  fit  into  two  corresponding  conical  tubes  (&,  A/),  made 
like  the  pipes  of  an  injecting  syringe,  so  that  they  can  be  readily  fitted  into  an 
artery.  A  stopcock  (&')  commands  the  channel  of  this  tube,  not  only  at  a', 
but  also  by  two  cogged  wheels,  at  a.  The  mechanism  of  this  arrangement 
may  be  readily  understood,  by  reference  to  the  adjoining  sections  of  this  por- 
tion of  the  instrument  at  B  and  C,  and  the  view  of  its  other  surface  at  D 
(r,  /  D).  At  h,  Ti'  are  two  short  tubes,  also  of  metal,  which  are  fitted  into 
the  horizontal  tube  below  the  stopcock,  and  so  that  their  channels  (as  shown  at 
C)  may  communicate  with,  and  be  exactly  equal  to,  that  of  the  horizontal  tube. 
The  stopcock  (If)  commands  this  communication  likewise.  These  short  tubes 
(A,  hf)  fit  exactly  upon  the  bent  glass  tube  (p,  p),  and  complete  the  communi- 
cation between  its  channel,  and  that  of  the  horizontal  tube  at  its  extremities. 
When  the  stopcock  is  turned  so  as  to  open  the  channel  of  the  horizontal  tube 

1  "Principles  of  Medicine,"  3d  Am.  Ed.,  p.  75. — Dr.  Williams  mentions,  what  the 
Author  has  himself  noticed,  that  the  radial  pulse,  in  cases  of  deficient  tonicity,  is  some- 
times felt  after  the  second  sound  of  the  heart  is  heard ;  a  fact  that  negatives  the  doctrine 
of  the  pulse  put  forward  by  Mr.  Colt  ("Medical  Gazette,"  vol.  xxxvi.  p.  456),  which  was 
founded  on  the  assumption  that  the  pulse  is  perceived  in  every  part  of  the  arterial  system 
previous  to  the  occurrence  of  the  second  sound  of  the  heart,  that  is,  before  the  closure  of 
the  aortic  valves.     The  Author  has  a  very  distinct  recollection  of  a  case  which  he  wit- 
nessed when  a  student  in  the  Middlesex  Hospital,  in  which  the  radial  pulse,  though  actu- 
ally synchronous  with  the  heart's  beat,  was  really  dependent  upon  the  preceding  ventricular 
systole ;  the  whole  of  the  interval  between  one  systole  and  another  being  required  for  the 
transmission  of  the  pulse-wave  from  the  heart  to  the  wrist,  as  was  proved  by  tracing  it 
from  the  centre  towards  the  periphery  of  the  arterial  system.     Now  in  this  case,  if  the 
marked  want  of  synchronism  between  the  pulse  at  the  wrist  and  in  the  neck  had  not 
excited  attention,  the  synchronism  between  the  radial  pulse  and  the  heart's  beat  would 
have  passed  as  an  ordinary  occurrence,  instead  of  being  a  very  extraordinary  phenomenon. 

2  On  this  very  important  point,  the  observations  of  Volkmann  are  in  full  accordance 
with  the  results  of  some  of  Hering's  experiments  performed  with  special  reference  to  it 
(2  509). 


MOVEMENT   OP   THE   BLOOD   IN   THE   ARTERIES. 


489 


throughout,  as  at  B,  all  communication  with  the  glass  tube  is  cut  off :  on  the 
other  hand,  when  the  communication  with  the  glass  tube  is  opened,  as  at  C, 
the  channel  of  the  horizontal  tube  is  stopped,  and  fluid  entering  at  a',  would 
have  to  pass  through  Ji',  and  to  traverse  both  limbs  of  the  glass  tube  (p,  p) 
emerging  at  a.  For  the  protection  of  the  instrument  in  using  it,  the  glass 
tube  is  attached  to  a  board,  to  which  is  fixed  a  scale  marked  in  metal. 

In  order  to  use  the  instrument,  a  large  artery  is  freely  exposed  for  not 
less  than  three  inches,  and,  after  due  precaution  has  been  taken  to  counteract 
hemorrhage,  it  is  divided  by  cutting  out  a  piece ;  the  conical  pipes  (&,  k') 
are  then  fixed  into  the  open  ends  of  the  artery,  one  being  directed  towards  the 


heart,  the  other  towards  the  capillaries.  -They  must  be  fixed  far  enough  apart, 
to  admit  of  the  introduction  of  the  horizontal  tube  (A)  between  them,  without 
altering  the  usual  direction  of  the  arterial  stream.  When  this  tube  is  fitted  to 
the  conical  pipes,  then  the  bent  glass  tube,  previously  filled  with  water,  must 
be  fixed  to  it  by  means  of  the  short  tubes  Qi,  hr,  C),  the  stopcock  being  so 


490  OF  THE   CIRCULATION   OP  THE  BLOOD. 

turned  as  to  shut  off  all  communication  with  the  glass  tube.  As  soon  as  the 
instrument  has  been  properly  fixed  in  the  artery,  the  blood  is  allowed  to  flow 
into  the  glass  tube.  It  may  be  now  seen  to  traverse  the  glass  tube  with  a 
velocity  very  nearly  the  same  as  it  has  in  the  artery,  and  in  doing  so,  it 
pushes  the  water  before  it  into  the  peripheral  bloodvessels,  with  (according  to 
Volkmann)  only  a  very  slight  admixture  between  the  two  fluids. 

By  trials  made  with  his  haemodronieter,  Volkmann  found,  in  the  case  of 
seven  dogs,  that  the  blood  flowed  in  their  carotids  with  a  velocity  ranging  be- 
tween 205  and  357  millimetres  in  a  second;  in  that  of  horses,  306  to  234;  in 
the  metatarsal  artery  of  the  horse,  56,  and  in  the  maxillary  artery  of  the  same 
animal,  99;  in  the  carotid  of  a  calf,  431.  The  average  velocity  in  the  carotids  of 
mammals  is  stated  by  Volkmann  to  be  3001  millimetres  in  a  second.3 — ED.]  It 
appears  from  the  observations  of  the  Profrs.  Weber  already  referred  to  (§  513), 
that  the  velocity  undergoes  a  marked  increase  in  branches  of  arteries  whose 
diameter  has  undergone  diminution  by  the  contraction  of  their  walls,  the  ac- 
celeration being  proportionate  to  the  narrowing  of  the  tube,  as  might  d  priori 
be  expected;  a  gradual  retardation  took  place  with  the  return  of  the  artery  to 
the  original  diameter ;  and  when,  as  sometimes  happened,  the  vessel  dilated  to 
more  than  its  former  dimensions,  a  positive  diminution  in  the  rate  of  move- 
ment of  the  blood  was  observable. 

519.  The  lateral  pressure  of  the  blood  against  the  walls  of  the  arteries  was 
aflirmed  by  Poisseuille  to  be  equal  throughout  the  whole  arterial  system;  but  the 
more  accurate  experiments  of  Volkmann  (made  with  Lud wig's  " kymographion," 
which  is  a  far  more  trustworthy  instrument  than  the  "  heemadynamometer"  of 
Poisseuille)  have  shown  that  this  is  far  from  being  correct.  The  pressure  of 
the  blood,  he  remarks,  is  no  constant  magnitude,  but  is  incessantly  changing 
according  to  the  stroke  of  the  heart,  the  movements  of  respiration,  and  the  mus- 
cular actions  of  the  body  generally.  A  gradual  diminution  of  its  amount,  how- 
ever, may  be  nearly  constantly  traced  from  the  commencement  of  the  arterial 
to  the  termination  of  the  venous  system;  and  this  is  to  be  partly  accounted  for 
by  the  increase  in  the  caliber  of  the  vascular  system,  which  takes  place  as  we 
pass  from  the  arterial  trunks  to  their  ramifications  (§  512),  and  still  more  from 
the  arterial  to  the  venous  system  (§  530);  and  partly  by  the  diminution  of  re- 
sistance (which  is  the  essential  cause  of  the  lateral  pressure)  as  the  blood  moves 
onwards  towards  its  point  of  discharge  (§  516).  The  following  table  presents 
the  results  of  Volkmann's  observations  (Op.  cit.,  p.  173)  upon  the  relative  lateral 
pressure  at  four  points  of  the  circulation  in  different  animals,  namely  (i.)  the 
carotid  near  its  origin,  (n.)  a  peripheral  branch  of  the  carotid  or  some  other 
artery,  (in.)  a  peripheral  rootlet  of  a  vein,  and  (iv.)  the  jugular  vein. 

i.  n.  in.  iv. 

Goat  .....        135  126  41  18 

Horse     'A      ......      -j;        122  97  44  21.5 

Calf 165.5  146  27.5  9 

A  blood-pressure  equivalent  to  a  column  of  mercury  160  millim.  6.3  (inches) 
in  height  was  assumed  by  Poisseuille  as  the  standard  for  all  arteries  and  for  all 
Mammalia,  and  therefore  (by  inference)  for  Man.  It  has  been  shown  by  Lud- 
wig  and  Volkmann,  however,  that  the  range  of  variation  is  very  wide,  being  in 
the  carotid  of  the  horse  from  150  to  321,  and  being  not  less  in  other  animals. 
Hence  it  is  obvious  that  no  precise  specification  can  be  laid  down  upon  this  point. 

1  Tolerably  close  approximations  to  the  value  of  these  measurements  in  English  inches, 
may  be  obtained  by  dividing  each  number  by  25. 

2  Todd  and  Bowman's  Physiological  Anatomy,  Am.  Ed. 


MOTION   OF  THE   BLOOD   IN    THE   CAPILLARIES.  491 


4. — Motion  of  the  filood  in  the  Capillaries. 

520.  We  now  come  to  the  last  head  of  the  inquiry  into  the  powers  which 
convey  the  blood  through  the  capillary  system;  that,  namely,  which  concerns 
the  agencies  existing  in  the  Capillaries  themselves.     Many  discussions  on  this 
subject  may, be  found  in  Physiological  writings:  and  it  has  so  immediate  a 
bearing  on  one  of  the  most  important  questions  in  Pathology — the  nature  of  In- 
flammation— that  it  deserves  the  fullest  attention.     The  chief  question  in  debate 
is  the  degree  in  which  the  Capillary  circulation  is  influenced  by  any  other 
agency  than  the  contractile  power  of  the  Heart  and  Arterial  system;    some 
Physiologists  maintaining,  that  this  alone  is  sufficient  to  account  for  all  the  phe- 
nomena of  the  Capillary  circulation;  and  others  asserting,  that  it  is  necessary 
to  admit  some  supplementary  force,  which  may  be  exerted  either  to  assist,  retard, 
or  regulate  the  flow  of  blood  from  the  Arteries  into  the  Veins.     We  shall  first 
consider  what  evidence  there  is  of  the  existence  of  any  such  force;  and,  when 
led  to  an  affirmative  conclusion,  we  shall  examine  into  its  nature. — No  physio- 
logical fact  seems  to  the  Author  to  be  more  clearly  proved,  than  the  existence, 
in  the  lower  classes  of  Animals,  as  well  as  in  Plants,  of  some  power  independent 
of  a  vis  a  tergo,  by  which  the  nutritive  fluid  is  caused  to  move  through  their 
vessels.1     This  power  seems  to  originate  in  the  circulation  itself,  and  to  be 
closely  connected  with  the  state  of  the  Nutritive  and  Secreting  processes :  since 
anything  which  stimulates  these  to  increased  energy  accelerates  the  movement; 
whilst  any  check  to  them  occasions  a  corresponding  stagnation.     It  may  be  con- 
venient to  designate  this  motor  force  by  the  name  of  capillary  power ;  it  being 
clearly  understood,  however,  that  no  mechanical  propulsion  is  thence  implied. 
On  ascending  the  Animal  scale,  we  find  the  power  which,  in  the  lower  organ- 
isms, is  diffused  through  the  whole  system,  gradually  concentrated  in  a  single 
part;  a  new  force,  that  of  the  Heart,  being  brought  into  operation,  and  the 
Circulation  placed,  in  a  greater  or  less  degree,  under  its  control.     Still  there  is 
evidence,  that  the  movement  of  blood  through  the  capillaries  is  not  entirely  due 
to  this;  since  it  may  continue  after  the  cessation  of  the  Heart's  action,  may 
itself  cease  in  particular  organs  when  the  Heart  is  still  acting  vigorously,  and 
is  constantly  being  affected  in  amount  and  rapidity,  by  causes  originating  in  the 
part  itself,  and  in  no  way  affecting  the  Heart. — The  chief  proofs  of  these  state- 
ments will  now  be  adverted  to. 

521.  When  the  flow  of  blood  through  the  Capillaries  of  a  transparent  part, 
such  as  the  web  of  a  Frog's  foot,  is  observed  with  the  Microscope,  it  appears  at 
first  to  take  place  with  great  evenness  and  regularity.     But  on  watching  the 
movement  for  some  time,  various  changes  may  be  observed,  which  cannot  be 
attributed  to  the  Heart's  influence,  and  which  show  that  a  certain  regulating  or 
distributive  power  exists  in  the  walls  of  the  capillaries,  or  in  the  tissues  which 
they  traverse.     Some  of  these  changes,  involving  variations  in  the  size  of  the 
capillary  tubes,  have  been  already  referred  to  (§  292).     Others,  however,  are 
manifested  in  great  and  sudden  alterations  in  the  velocity  of  the  current;  which 
cause  a  marked  difference  in  the  rates  of  the  movement  of  the  blood  through 
the  several  parts  of  the  area  under  observation.     Sometimes  this  variation  ex- 
tends even  to  the  entire  reversal,  for  a  time,  of  the  direction  of  the  movement, 
in  certain  of  the  transverse  or  communicating  branches;  the  flow  always  taking 
place,  of  course,  from  the  stronger  towards  the  weaker  current.     Not  unfre- 
quently,  an  entire  stagnation  of  the  current  in  some  particular  tube,  precedes 
this  reversal  of  its  direction.     Irregularities  of  this  kind,  however,  are  more 
frequent  when  the  Heart's  action  is  partly  interrupted;  as  it  usually  is  by  the 

1  See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  CHAP,  xn.,  Am.  Ed. 


492  OF   THE   CIRCULATION   OP   THE   BLOOD. 

pressure  to  which  the  tadpole  or  other  animal  must  be  subjected,  in  order  to 
allow  microscopic  observations  to  be  made  upon  its  circulation.  Under  such 
circumstances,  the  varieties  in  the  capillary  circulation,  induced  by  causes  purely 
local,  become  very  conspicuous;  for  when  the  whole  current  is  nearly  stagnated, 
and  a  fresh  impulse  from  the  heart  renews  it,  the  movement  is  not  by  any  means 
uniform  (as  it  might  have  been  expected  to  be)  through  the  whole  plexus  sup- 
plied by  one  arterial  trunk,  but  is  much  greater  in  some  of  the  tubes  than  it  is 
in  others;  the  variation  being  in  no  degree  connected  with  their  size,  and  being 
very  different  at  short  intervals. 

522.  The  movement  of  the  blood  in  the  Capillaries  of  cold-blooded  animals, 
after  complete  excision  of  the  Heart,  has  been  repeatedly  witnessed.     In  warm- 
blooded animals,  this  cannot  be  satisfactorily  established  by  experiment,  since 
the  shock  occasioned  by  so  severe  an  operation  much  sooner  destroys  the  gene- 
ral vitality  of  the  system;  but  it  may  be  proved  in  other  ways  to  take  place. 
After  most  kinds  of  natural  death,  the  arterial  system  is  found,  subsequently  to 
the  lapse  of  a  few  hours,  almost  or  completely  emptied  of  blood;  this  is  partly, 
no  doubt,  the  effect  of  the  tonic  contraction  of  the  tubes  themselves ;  but  the 
emptying  is  commonly  more  complete  than  could  be  thus  accounted  for,  and 
must  therefore  be  partly  due  to  the  continuance  of  the  capillary  circulation.     It 
has  been  observed  by  Dr.  Bennett  Dowler,1  that  in  the  bodies  of  individuals 
w)io  have  died  from  yellow  fever  (such  as  exhibited  the  remarkable  post-mortem 
movements  already  noticed,  §  328),  the  external  veins  frequently  become  so 
distended  with  blood  within  a  few  minutes  after  the  cessation  of  the  heart's  ac- 
tion, that,  when  they  are  opened,  the  blood  flows  in  a  good  stream,  being  some- 
times projected  to  the  distance  of  a  foot  or  more,  especially  when  pressure  was 
applied  above  the  puncture,  as  in  ordinary  bloodletting.     It  is  not  conceivable 
that  the  slowly  acting  tonicity  of  the  arteries  should  have  produced  such  a  result 
as  this ;  which  can  scarcely,  therefore,  be  attributed  to  anything  else  than  the 
sustenance  of  the  capillary  circulation  by  forces  generated  within  itself.     Fur- 
ther, it  has  been  well  ascertained  that  a  real  process  of  secretion  not  unfrequently 
continues  after  general  or  somatic  death ;  urine  has  been  poured  out  by  the 
ureters,  sweat  exuded  from  the  skin,  and  other  peculiar  secretions  formed  by 
their  glands;  and  these  changes  could  scarcely  have  taken  place,  unless  the 
capillary  circulation  were  still  continuing.     In  the  early  embryonic  condition  of 
the  highest  animals,  the  movement  of  blood  seems  to  be  unquestionably  due  to 
some  diffused  power,  independent  of  any  central  impulsion;  for  it  may  be  seen 
to  commence  in  the  Vascular  Area,  before  it  is  subjected  to  the  influence  of  the 
Heart.     The  first  movement  is  towards,  instead  of  from,  the  centre ;  and  even 
for  some  time  after  the  circulation  is  fairly  established,  the  walls  of  the  Heart 
consist  merely  of  cells  loosely  attached  together,  and  can  hardly  be  supposed  to 
have  any  great  contractile  power. 

523.  The  last  of  these  facts  may  be  said  not  to  have  any  direct  bearing  on 
the  question,  whether  the  "capillary  power"  has  any  existence  in  the  adult 
condition;  but  the  phenomena  occasionally  presented  by  the  foetus,  at  a  later 
stage,  appear  decisive.     Cases  are  of  no  very  unfrequent  occurrence,  in  which 
the  heart  is  absent  during  the  whole  of  embryonic  life,  and  yet  the  greater  part 
of  the  organs  are  well  developed.     In  most  or  all  of  these  cases,  it  is  true  a 
perfect  twin  foetus  exists,  of  which  the  placenta  is  in  some  degree  united  with 
that  of  the  imperfect  one ;  and  it  has  been  customary  to  attribute  the  circulation 
in  the  latter  to  the  influence  of  the  heart  of  the  former,  propagated  through  the 
placental  vessels.     This  supposition  has  not  been  disproved  (however  improbable 
it  might  seem)  until  recently ;  when  a  case  of  this  kind  occurred,  which  was 

*  "Researches,  Critical  and  Experimental,  on  the  Capillary  Circulation,"  reprinted  from 
the  "New  Orleans  Medical  and  Surgical  Journal,"  Jan.  1849. 


MOTION   OF  THE   BLOOD   IN   THE   CAPILLARIES.  493 

submitted  to  the  most  careful  examination  by  an  accomplished  anatomist  ;*  and 
this  decisive  result  was  obtained,  that  it  seemed  impossible  for  the  heart  of  the 
twin  foetus  to  have  occasioned  the  movement  of  blood  in  the  imperfect  one,  and 
that  some  cause  present  in  the  latter  must  have  been  sufficient  for  the  propulsion 
of  blood  through  its  vessels.  It  was  a  very  curious  anomaly  in  this  case,  that 
the  usual  functions  of  the  arteries  and  veins  must  have  been  reversed ;  for  the 
Vena  Cava,  receiving  its  blood  from  the  umbilical  vein  nearly  as  usual,  had  no 
communication  with  the  Arterial  system  (the  Heart  being  absent),  except 
through  the  systemic  capillaries;  to  which,  therefore,  the  blood  must  have 
next  proceeded,  returning  to  the  placenta  by  the  umbilical  artery.  This  view 
of  the  course  of  the  blood  was  confirmed  by  the  fact,  that  the  veins  were  every- 
where destitute  of  valves. — It  is  evident  that  a  single  case  of  this  kind,  if 
unequivocally  demonstrated,  furnishes  all  the  proof  that  can  be  needed,  of  the 
existence,  even  in  the  highest  animals,  of  a  "  capillary  power  j"  which,  though 
usually  subordinate  to  the  Heart's  action,  is  sufficiently  strong  to  maintain  the 
circulation  by  itself,  when  the  power  of  the  central  organ  is  diminished.  In 
this,  as  in  many  other  cases,  we  may  observe  a  remarkable  capability  in  the 
living  system,  of  adapting  itself  to  exigencies.  In  the  acardiac  Foetus,  the 
"  capillary  power"  supplies  the  place  of  the  Heart,  up  to  the  period  of  birth  ] 
after  which,  of  course,  the  circulation  ceases,  for  want  of  due  aeration  of  the 
blood.  It  has  occasionally  been  noticed,  that  a  gradual  degeneration  in  the 
structure  of  the  Heart  has  taken  place  during  life,  to  such  an  extent  that  scarcely 
any  muscular  tissue  could  at  last  be  detected  in  it,  but  without  any  such  inter- 
ruption to  the  circulation  as  must  have  been  anticipated,  if  this  organ  furnished 
the  sole  impelling  force. 

524.  Further,  it  is  a  general  principle,  unquestioned  by  any  Physiologist, 
and  embodied  in  the  ancient  aphorism  Ubi  stimulus  ibifluxm,  that,  when  there 
is  any  local  excitement  to  the  processes  of  Nutrition,  Secretion,  &c.,  a  determi- 
nation of  blood  towards  the  part  speedily  takes  place,  and  the  motion  of  blood 
through  it>  is  increased  in  rapidity  j  and  although  it  might  be  urged  that  this 
increased  determination  may  not  be  the  effect,  but  the  cause,  of  the  increased 
local  action,  such  an  opinion  could  not  be  sustained  without  many  inconsistencies 
with  positive  facts.     For  it  is  known  that  such  local  determinations  may  take 
place,  not  only  as  a  part  of  the  regular  phenomena  of  growth  and  development 
(as  in  the  case  of  the  entire  genital  system  at  the  time  of  puberty  and  of 
periodical  heat,  the  uterus  after  conception,  and  the  mammae  after  parturition), 
but  also  as  a  consequence  of  a  strictly  local  cause.     Thus,  the  student  is  well 
aware  that,  after  several  hours'  close  application,  there  is  commonly  an  increased 
determination  of  blood  to  the  brain,  causing  a  sense  of  oppression,  a  feeling  of 
heat,  and  frequently  a  diminished  action  in  other  parts ;  and,  again,  when  the 
capillary  circulation  is  being  examined  under  the  microscope,  it  is  seen  to  be 
quickened  by  moderate  stimuli,  and  to  be  equally  retarded  by  depressing  agents. 
All  these  facts  harmonize  completely  with  the  phenomena,  which  are  yet  more 
striking  in  the  lower  classes  of  organized  beings,  and  which  are  evidently  in 
accordance  with  the  same  laws. 

525.  It  is  equally  capable  of  proof,  on  the  other  hand,  that  an  influence  gene- 
rated in  the  Capillaries  may  afford  a  complete  check  to  the  circulation  in  the 
part;  even  when  the  Heart's  action  is  unimpaired,  and  no  mechanical  impedi- 
ment exists  to  the  transmission  of  blood.     Thus,  cases  of  spontaneous  gangrene 
of  the  lower  extremities  are  of  no  unfrequent  occurrence,  in  which  the  death  of 

1  See  Dr.  Houston  in  "the  Dublin  Medical  Journal,"  1837.  An  attempt  was  made  by 
Dr.  M.  Hall  ("Edinb.  Monthly  Journal,"  1843)  to  disprove  Dr.  Houston's  inferences;  but 
a  most  satisfactory  reply  was  given  by  Dr.  Houston,  at  the  Meeting  of  the  British  Asso- 
ciation, August,  1843,  and  published  in  the  "Dublin  Journal,"  Jan.,  1844.  See  also 
"Edinb.  Med.  and  Surg.  Journ.,"  July,  1844. 


494  OP   THE    CIRCULATION    OP   THE   BLOOD. 

the  solid  tissues  is  clearly  connected  with  a  local  decline  of  the  circulation  ]  and 
in  which  it  has  been  shown,  by  examination  of  the  limb  after  its  removal,  that 
both  the  larger  tubes  and  the  capillaries  were  completely  pervious ;  so  that  the 
cessation  of  the  flow  of  blood  could  not  be  attributed  to  any  impediment,  except 
that  arising  from  the  cessation  of  some  power  which  exists  in  the  capillaries, 
and  which  is  necessary  for  the  maintenance  of  the  current  through  them.  The 
influence  of  the  prolonged  application  of  Cold  to  a  part  may  be  quoted  in  sup- 
port of  the  same  general  proposition ;  for,  although  the  caliber  of  the  vessels 
may  be  diminished  by  this  agent,  yet  their  contraction  is  not  sufficient  to  ac- 
count for  that  complete  cessation  of  the  flow  of  blood  through  them,  which  is 
well  known  to  occur,  and  to  terminate  in  the  loss  of  their  vitality.  The  most 
remarkable  evidence  on  this  point,  however,  is  derived  from  the  phenomena  of 
Asphyxia,  which  will  be  more  fully  explained  in  the  succeeding  Chapter  (Sect. 
3).  At  present  it  may  be  stated  as  a  fact,  which  has  now  been  very  satisfac- 
torily ascertained,  that,  if  admission  of  air  into  the  lungs  be  prevented,  the  cir- 
culation through  them  will  be  brought  to  a  stand,  as  soon  as  the  air  which  they 
contain  has  been  to  a  great  degree  deprived  of  its  oxygen,  or  rather  has  become 
loaded  with  carbonic  acid ;  and  this  stagnation  will,  of  course,  be  communicated 
to  all  the  rest  of  the  system.  Yet,  if  it  have  not  continued  sufficiently  long  to 
cause  the  loss  of  vitality  in  the  nervous  centres,  the  movement  may  be  renewed 
by  the  admission  of  air  into  the  lungs.  Now,  although  it  has  been  asserted  that 
the  stagnation  is  due  to  a  mechanical  impediment,  resulting  from  the  contracted 
state  of  the  lungs  in  such  cases,  this  has  been  clearly  proved  not  to  be  the  fact 
by  causing  animals  to  breathe  a  gas  destitute  of  oxygen,  so  as  to  produce  As- 
phyxia in  a  different  manner ;  for  the  same  stagnation  results,  as  in  the  other 
case. 

526.  If  the  phenomena  which  have  been  here  brought  together  be  considered 
as  establishing  the  existence,  in  all  classes  of  beings  possessing  a  circulating 
apparatus,  of  a  "  Capillary  power/'  which  affords  a  necessary  condition  for  the 
movement  of  the  nutritious  fluid,  through  those  parts  in  which  it  comes  into 
more  immediate  relation  with  the  solids,  the  question  still  remains  open,  what 
is  the  nature  of  that  power. — It  is  very  doubtful  whether  the  Capillaries  possess 
true  contractility ;  for,  although  their  diameter  is  subject  to  great  variation,  yet 
this  may  be  due  simply  to  the  elasticity  of  their  walls,  which  tends  to  keep  them 
constantly  contracted  upon  the  stream  of  blood  that  passes  through  them ;  and 
there  is  no  adequate  proof  that  the  alterations  in  their  size,  which  are  consequent 
upon  the  local  application  of  stimuli,  proceed  from  any  other  source  than 
the  alteration  in  the  quantity  of  blood  delivered  to  them  by  the  minute  arteries, 
the  very  considerable  alterations  in  whose  caliber  under  such  influences  have 
been  already  described  (§  513).  In  the  experiments  of  the  Profrs.  Weber  (loc. 
cit.)  the  application  of  the  electric  stimulus  to  the  capillaries  produced  no  change 
in  their  diameter.  Even  supposing  the  capillaries,  however,  to  possess  such  an 
independent  contractility,  this  could  not  exert  itself  in  aiding  the  flow  of  blood 
through  them,  except  either  by  rhythmical  alternations  of  contraction  and  dilata- 
tion, or  by  some  kind  of  peristaltic  movement ;  and  observation  completely  ne- 
gatives the  idea  of  the  existence  of  any  such  movement,  since  the  stream  of 
blood,  now  rendered  continuous  by  the  elasticity  of  the  arteries,  passes  through 
the  capillaries  as  through  tubes  of  glass.  Hence  the  notion  of  any  mechanical 
assistance,  afforded  by  the  action  of  the  walls  of  the  Capillaries  to  the  movement 
of  blood  through  them,  must  be  altogether  dismissed. — There  is  experimental 
evidence,  however,  that  the  movement  of  the  blood  may  be  affected  by  any 
agency  which  alters  the  chemico-vital  relations  between  the  blood  and  the  tissues 
which  it  permeates.  Thus,  when  the  interrupted  electric  current  was  applied 
to  the  capillaries  by  the  Profrs.  Weber,  they  noticed  that  the  blood-corpuscles 
showed  a  remarkable  tendency  to  adhere  to  each  other  and  to  the  walls  of  the 


MOTION   OP   THE   BLOOD   IN   THE   CAPILLARIES.  495 

vessels,  so  as  to  produce  a  great  amount  of  friction  and  a  consequent  retardation ; 
the  continual  arrival  of  new  corpuscles  thus  produces  an  accumulation  which 
completely  fills  the  vessels  of  the  part,  and  thus  occasions  a  total  stagnation ; 
but  this  gives  place  to  the  renewal  of  the  current,  by  the  dispersion  of  the  cor- 
puscles, soon  after  the  withdrawal  of  the  stimulus.  A  very  similar  set  of 
phenomena  has  been  observed  by  Mr.  Wharton  Jones,1  as  the  consequence  of  the 
direction  of  a  stream  of  carbonic  acid  against  the  capillary  network.  And  the 
depression  of  the  vitality  of  the  part,  by  such  injuries  as  tend  to  excite  Inflamma- 
tion in  it,  produces  a  like  stagnation.  This  effect  cannot  be  attributed  to  me- 
chanical obstruction  in  the  vessels,  for  they  are  usually  dilated,  rather  than 
contracted,  when  this  condition  exists ;  and  without  any  change  in  the  dimen- 
sions of  a  tube,  the  stream  of  blood  through  it  may  be  seen  decreasing  from 
extreme  velocity  to  complete  stagnation.3 — That  alterations  in  the  chemical 
state  of  the  blood  (involving,  of  Bourse,  important  changes  in  its  vital  properties) 
are  capable  of  exercising  a  most  important  effect  on  the  Capillary  circulation, 
is  shown,  not  merely  by  the  stagnation  of  the  pulmonary  Circulation  in  As- 
phyxia (§  574),  but  by  the  curious  fact  ascertained  by  Dr.  J.  Reid,3  that  the  blood, 
when  imperfectly  arterialized,  is  retarded  in  the  systemic  capillaries,  causing  an 
increased  pressure  on  the  walls  of  the  arteries.  He  found  that,  when  the  in- 
gress of  air  through  the  trachea  of  a  Dog  was  prevented,  and  the  Asphyxia  was 
proceeding  to  the  stage  of  insensibility — the  attempts  at  inspiration  being  few 
and  labored,  and  the  blood  in  an  exposed  artery  being  quite  venous  in  its  cha- 
racter— the  pressure  upon  the  arterial  walls,  as  indicated  by  the  hsemadynamo- 
meter  applied  to  the  femoral  artery,  was  much  greater  than  usual.  Upon  ap- 
plying a  similar  test  to  a  vein,  however,  it  was  found  that  the  pressure  was 
proportionably  diminished;  whence  it  became ' apparent,  that  there  was  an  un- 
usual obstruction  to  the  passage  of  venous  blood  through  the  systemic  capilla- 
ries. After  this  period,  however,  the  mercury  in  the  hsemadynamoineter 
applied  to  the  artery  began  to  fall  steadily,  and  at  last  rapidly,  in  consequence 
of  the  diminished  force  of  the  heart,  and  the  retardation  of  the  blood  in  the 
pulmonic  capillaries ;  but,  if  atmospheric  air  was  admitted,  the  mercury  rose 
instantly,  showing  that  the  renewal  of  the  proper  chemical  state  of  the  blood 
restored  the  condition  necessary  for  its  circulation  through  the  capillaries.4 

527.  It  appears,  from  the  preceding  facts,  that  the  conditions,  under  which 
the  power  in  question  uniformly  operates,  may  be  thus  simply  and  defi- 
nitely expressed:  Whilst  the  injection  of  blood  into  the  Capillary  vessels  of 
every  part  of  the  system  is  due  to  the  action  of  the  Heart,  its  rate  of  passage 
through  those  vessels  is  greatly  modified  by  the  degree  of  activity  ii^the 
processes  to  which  it  should  normally  be  subservient  in  them; — the  current 
being  rendered  more  rapid  by  an  increase  in  their  activity,  and  being  stagnated 
by  their  depression  or  total  cessation.  Or  at  any  rate,  to  use  the  more  guarded 
language  of  Mr.  Paget  (loc.  cit.),  "we  have  facts  enough  to  justify  such  an 
hypothesis,  as  that  there  may  be  some  mutual  relation  between  the  blood  and 
its  vessels,  or  the  parts  around  them,  which,  being  natural,  permits  the  most 
easy  transit  of  the  blood,  but,  being  disturbed,  increases  the  hindrances  to  its 

1  "Brit,  and  For.  Med.  Review,"  vol.  xiv.  p.  600. 

2  See  Mr.  Paget,  loc.  cit.,  p.  971. — The  Author  had  long  previously  satisfied  himself 
that  such  was  the  fact ;  and  is  glad  to  be  able  to  cite  the  far  more  extended  observations 
of  Mr.  Paget  on  this  point,  in  confirmation  of  his  own. 

'3  "Edinb.  Med.  and  Surg.  Journ.,"  April,  1841;  and  "Anat.,  Phys,,  and  Pathol.  Re- 
searches," chap.  ii. 

4  This  last  fact  (as  Dr.  Eeid  has  remarked)  is  sufficient  to  negative  the  idea  of  Mr. 
Erichsen,  that  the  obstruction  is  caused  by  the  contraction  of  the  capillaries  under  the 
stimulus  of  venous  blood  ("Edinb.  Med.  and  Surg.  Journal,"  Jan.,  1845) ;  for  all  experi- 
ments agree  in  showing  that  such  contraction  can  only  be  excited  by  the  application  of  a 
stimulus  for  some  minutes,  and  that  relaxation  takes  place  still  more  slowly  ($  513). 


496  OP   THE   CIRCULATION   OF  THE   BLOOD. 

passage." — A  physical  principle  which  has  been  put  forth  by  Prof.  Draper1 
seems  quite  adequate  to  explain  these  phenomena.  It  seems  fully  capable  of 
proof  that  "if  two  liquids  communicate  with  one  another  in  a  capillary  tube, 
or  in  a  porous  or  parenchymatous  structure,  and  have  for  that  tube  or  structure 
different  chemical  affinities,  movement  will  ensue;  that  liquid  which  has  the  most 
energetic  affinity  will  move  with  the  greatest  velocity,  and  may  even  drive  the 
other  liquid  before  it."  Now  Arterial  blood — -containing  oxygen  with  which  it  is 
ready  to  part,  and  being  prepared  to  receive  in  exchange  the  carbonic  acid  which 
the  tissues  set  free — must  obviously  have  a  greater  affinity  for  those  tissues,  than 
Venous  blood,  in  which  both  these  changes  have  already  been  effected.  Con- 
sequently, upon  mere  physical  principles,  the  arterial  blood  which  enters  the 
Systemic  capillaries  on  one  side  must  drive  before  it,  and  expel  on  the  other 
side  of  the  network,  the  blood  which  has  become  venous  whilst  traversing  it; 
but  if  the  blood  which  enters  the  capillaries  have  no  such  affinity,  no  such  motor 
power  can  be  developed. — On  the  other  hand,  in  the  Pulmonary  capillaries  the 
opposite  affinities  prevail.  The  venous  blood  and  the  air  iri  the  cells  of  the 
lungs  have  a  mutual  attraction,  which  is  satisfied  by  the  exchange  of  oxygen  and 
carbonic  acid  that  takes  place  through  the  walls  of  the  capillaries ;  and  when 
the  blood  has  become  arterialized,  it  no  longer  has  any  attraction  for  the  air. 
Upon  the  very  same  principle,  therefore,  the  venous  blood  will  drive  the  arterial 
before  it,  in  the  pulmonary  capillaries,  whilst  respiration  is  properly  going  on ; 
but  if  the  supply  of  oxygen  be  interrupted,  so  that  the  blood  is  no  longer  aerated, 
no  change  in  the  affinities  takes  place  whilst  it  traverses  the  capillary  net-work ; 
the  blood  continuing  venous,  still  retains  its  need  of  a  change,  and  its  attrac- 
tion for  the  walls  of  the  capillaries;  and  its  egress  into  the  pulmonary  veins  is 
thus  resisted,  rather  than  aided,  by  the  force  generated  in  the  lungs. — The 
change  in  the  condition  of  the  blood,  in  regard  to  the  relative  proportions  of 
its  oxygen  and  carbonic  acid,  is  the  only  one  to  which  the  Pulmonary  circula- 
tion is  subservient;  but  in  the  Systemic  circulation,  the  changes  are  of  a  much 
more  complex  nature,  every  distinct  organ  attracting  to  itself  the  peculiar  sub- 
stances which  it  requires  as  the  materials  of  its  own  nutrition,  and  the  nature 
of  the  affinities  thus  generated  being  consequently  different  in  each  case.  But 
the  same  law  may  be  considered  to  hold  good  in  all  instances.  Thus  the  blood 
conveyed  to  the  Liver  by  the  portal  vein,  contains  the  materials  at  the  expense 
of  which  the  bile-secreting  cells  are  developed;  consequently,  the  tissue  of  the 
liver,  which  is  principally  made  up  of  these  cells,  possesses  a  certain  degree  of 
affinity  or  attraction  for  blood  containing  these  materials ;  and  this  is  diminished, 
so  soon  as  they  have  been  drawn  from  it  into  the  cell  around.  Consequently 
theHcJlood  of  the  portal  vein  will  drive  before  it,  into  the  hepatic  vein,  the  blood 
which  has  traversed  the  capillaries  of  the  portal  system,  and  which  has  given 
up,  in  doing  so,  the  elements  of  bile  to  the  solid  tissues  of  the  liver. 

528.  It  can  be  scarcely  doubted  that  it  is  by  some  influence  exercised  over 
the  molecular  actions,  to  which  the  blood  is  subject  in  the  capillaries,  that  the 
Nervous  system  can  operate  on  the  functions  of  Nutrition,  Secretion,  &c. 
(§§  381,  385) ;  and  this  influence  can  scarcely  be  considered  in  any  other  light 
than  as  a  peculiar  manifestation  of  vital  force  (§  352).  The  following  experi- 
ment made  by  Dr.  Wilson  Philip  exhibits  the  effect  of  "shock"  upon  the 
capillary  circulation.  "The  web  of  one  of  the  hind  legs  of  a  frog  was  brought 
before  the  microscope ;  and  while  Dr.  Hastings  observed  the  circulation,  which 
was  vigorous,  the  brain  was  crushed  by  the  blow  of  a  hammer.  The  vessels  of 
the  web  instantly  lost  their  power,  the  circulation  ceasing;  an  effect  which  can- 
not arise,  as  we  have  seen,  from  the  ceasing  of  the  action  of  the  heart.  [Dr. 
P.  here  refers  to  experiments,  by  which  it  was  ascertained,  that  the  circulation 

1  "Treatise  on  the  Forces  which  produce  the  Organization  of  Plants,"  pp.  22-41. 


MOTION   OF    THE    BLOOD    IN   THE    VEINS.  t     497 

in  the  capillary  vessels  of  the  frog  will  continue  for  several  minutes  after  the 
interruption  of  the  heart's  action.]  In  a  short  time,  the  blood  again  began  to 
move,  but  with  less  force.  This  experiment  was  repeated,  with  the  same  result. 
If  the  brain  is  not  completely  crushed,  although  the  animal  is  killed,  the  blow, 
instead  of  destroying  the  circulation,  increases  the  rapidity.'71  We  are  not 
hence  to  conclude,  however,  that  the  Nervous  system  supplies  any  influence 
which  is  essential  to  the  continuance  of  the  Circulation  ;  since  it  is  only  by  such 
sudden  and  severe  injuries  to  the  nervous  centres,  as  instantaneously  destroy 
the  vitality  of  the  whole  system  (§  321),  that  the  movement  of  the  blood  is 
arrested. — The  experiments  of  Miiller  and  others  satisfactorily  prove  that  the 
ordinary  action  of  the  Nerves  does  not  produce  any  direct  effect  upon  the 
capillary  circulation)  and  this  corresponds  with  the  well-known  fact  that  the 
Nutritive  processes  may  continue  as  usual  after  this  action  has  been  suspended. 
All  the  facts  which  bear  upon  the  question  of  the  connection  between  Nervous 
agency  and  the  forces  maintaining  the  capillary  circulation  have  an  equal  rela- 
tion to  the  functions  of  Nutrition  and  Secretion  in  general;  and,  as  already 
shown,  the  Nervous  system  also  influences  these,  by  the  control  it  exerts  over 
the  diameter  of  the  bloodvessels  (§  515). 

529.  The  average  rate  of  movement  of  the  blood  through  the  capillary  sys- 
tem may  be  determined  with  tolerable  precision  by  microscopic  measurement ; 
and  the  observations  of  Hales,  Valentin,   and  Weber  concur  in  representing 
it  to  be  from  1  inch  to  1?  inch  per  minute  in  the   systemic  capillaries  of  the 
Frog;  1.2  inch  per  minute,  or  .02  inch  per  second,  being  about-  the  average. 
In  warm-blooded  animals,  however,  the  capillary  circulation  is  probably  much 
more  rapid  than  this;  the  observations  of  Yolkmann  upon  the  mesenteric  arteries 
of  the  Dog  make  its  rate  about  .03  inch  per  second,  or  1.8  inch  per  minute;  and  it 
seems  reasonable  to  suppose  that  the  exposure  of  the  membrane  to  the  cool  air 
would  produce  a  considerable  reduction  in  the  normal  rapidity  of  the  flow  of 
blood  through  it.     Assuming  .03  inch  per  second,  however,  as  the  rate,  and 
comparing  this  with  the  rate  of  movement  of  the  blood  in  the  larger  arteries, 
which  seem  on  the  average  to  be  11.8  inches  per  second,  it  is  calculated  by 
Volkmann  that  the  aggregate  area  of  the  capillaries  (being  in  an  inverse  ratio 
to  the  rate  of  the  blood's  movement  through  them)  must  be  nearly  four  hundred 
times  that  of  the  arterial  trunks  which  supply  them.2 

5. — Motion  of  the  Blood  in  the  Veins. 

530.  The  Venous  system  takes  its  origin  in  the  small  trunks  that  are  formed 
by  the  reunion  of  the  Capillaries;  and  it  returns  the  blood  from  these  &  the 
Heart.     The  structure  of  the  Veins  is  essentially  the  same  with  that  of  the 
Arteries ;  but  the  fibrous  tissue  of  which  their  middle  coat  is  made  up,  bears 
more  resemblance  to  the  areolar  tissue  of  the  skin,  than  it  does  to  the  true  elastic 
tissue ;  and  the  muscular  fibre-cells  are  usually  much  fewer  in  number,  and  are 
sometimes  wanting  altogether.3     The  elasticity  of  the  Veins  is  shown  by  the  jet 
of  blood  which  at  first  spouts  out  in  ordinary  venesection,  when,  by  means  of 
the  ligature,  a  distension  has  been  occasioned  in  the  tubes  below  it.     A  slight 
contractility  on  the  application  of  stimuli,  and  on  irritation  of  the  Sympathetic 
nervous  fibres,  has  been  observed ;  but  this  is  not  so  decided  as  in  the  arteries. 

1  "Experimental  Inquiry  into  the  Laws  of  the  Vital  Functions,"  4th  edition,  p.  52. 

2  "Hiimodynamik,"  pp.  184,  204. 

3  The  following,  according  to  Prof.  Kolliker,  are  veins  which  are  unprovided  with  mus- 
cular structure  :   The  veins  of  the  uterine  portion  of  the  placenta ;  the  veins  of  the  cere- 
bral substance,  the  sinuses  of  the  dura  mater  ;  Breschet's  veins  of  the  bones  ;  the  venous 
cells  of  the  corpora  cavernosa  in  the  male  and  female ;  and  probably  the  venous  cells  of 
the  spleen.     ("  Kolliker  and  Siebold's  Zeitschrift,"  1849.) 

32 


498     t  OP   THE   CIRCULATION   OF   THE   BLOOD. 

The  whole  capacity  of  the  Venous  system  is  considerably  greater  than  that  of 
the  arterial;  the  former  is  usually  estimated  to  contain  from  2  to  3  times  as 
much  blood  as  the  latter,  in  the  ordinary  condition  of  the  circulation ;  and  when 
we  consider  the  great  proportion,  which  the  Veins  in  almost  every  part  of  the 
body  bear  to  the  arteries,  we  shall  scarcely  regard  even  the  larger  of  these  ratios 
as  exaggerated.  Of  course  the  rapidity  of  the  movement  of  the  blood  in  the 
two  systems  will  bear  an  inverse  ratio  to  their  respective  capacities ;  thus  if,  in 
a  given  length,  the  veins  contain  three  times  as  much  blood  as  the  arteries,  the 
fluid  will  move  with  only  one-third  of  the  velocity.  Even  at  their  origins  in 
the  capillary  plexus,  the  veins  are  larger  than  the  arteries  which  terminate  in 
the  same  plexus ;  so  that,  wherever  the  arterial  and  venous  networks  form 
distinct  strata,  they  are  readily  distinguished  from  each  other.  The  Veins  are 
remarkable  for  the  number  of  valves  which  they  contain,  formed  of  duplicatures 
or  loose  folds  of  the  internal  tunic,  between  the  component  laminae  of  which, 
contractile  fibres  are  interposed;  and  also  for  the  dilatations  behind  these,  which, 
when  distended,  give  them  a  varicose  appearance.  The  valves  are  single  in  the 
small  veins,  the  free  edge  of  the  flap  closing  against  the  opposite  wall  of  the 
vein ;  in  the  larger  trunks  they  are  double ;  and  in  a  few  instances  they  are 
composed  of  three  flaps.  The  object  of  these  valves  is  evidently  to  prevent 
the  reflux  of  blood;  and  we  shall  presently  see,  that  they  are  of  important  use 
in  assisting  in  the  maintenance  of  the  venous  circulation.  They  are  most 
numerous  in  those  veins  which  run  among  parts  affected  by  muscular  move- 
ment ;  and  they  are  not  found  in  the  veins  of  the  lungs,  of  the  abdominal 
viscera,  or  of  the  brain. 

531.  The  movement  of  the  blood  through  the  Veins  is,  without  doubt,  chief- 
ly effected  by  the  vis  d  tergo  or  propulsive  force,  which  results  from  the  action 
of  the  heart  and  arteries ;  this,  as  already  shown  (§  519),  is  very  greatly  dimin- 
ished by  the  time  that  it  acts  on  the  blood  in  the  veins;  but  the  resistance  to 
the  onward  movement  of  the  blood  is  now  so  slight  that  a  very  feeble  power  is 
adequate  to  overcome  it.  There  are  some  ^concurrent  causes,  however,  which 
are  supposed  by  some  to  have  much  influence  upon  it,  and  of  which  the  consider- 
ation must  not  be  neglected. — One  of  these  is  the  suction-power  attributed  to 
the  Heart ;  acting  as  a  vis  d  fronte,  in  drawing  the  blood  towards  it.  It  is 
doubtful  how  far  the  Auricles  have  such  a  power  of  active  dilatation,  as  that 
which  would  be  required  for  this  purpose ;  and  no  sufficient  evidence  has  been 
given  that  the  current  of  blood  at  any  distance. from  the  Heart  is  affected  by  it. 
Indeed,  for  a  reason  to  be  presently  stated,  this  may  be  regarded  as  impossible. 
— Another  important  agency  has  been  found  by  some  Physiologists,  in  the  in- 
spiratory  movement ;  this  is  supposed  to  draw  the  blood  of  the  Veins  into  the 
chest,  in  order  to  supply  the  vacuum  which  is  created  there,  at  the  moment  of 
the  descent  of  the  diaphragm.  That  the  movement  in  question  has  some  influ- 
ence on  the  flow  of  venous  blood  into  the  chest,  is  evident  from  the  occurrence  of 
the  respiratory  pulse,  long  ago  described  by  Haller ;  which  may  be  seen  in  the 
veins  of  the  neck  and  shoulder  in  thin  persons,  and  in  those  especially  who  are 
suffering  from  pulmonary  diseases.  During  Inspiration,  the  Veins  are  seen  to 
be  partially  emptied :  whilst  during  Expiration  they  become  turgid,  partly  in 
consequence  of  the  accumulation  from  behind,  and  of  the  check  in  front;  and 
partly  (it  may  be)  in  some  cases,  through  an  absolute  reflux  from  the  veins 
within  the  chest  (§  504).  The  fact  that,  in  the  immediate  neighborhood  of  the 
chest,  the  flow  of  blood  towards  the  heart  is  aided  by  inspiration  and  impeded 
by  expiration,  is  further  proved  by  Sir  D.  Barry's  experiment,  which  consisted 
in  introducing  one  extremity  of  a  tube  into  the  jugular  vein  of  a  Horse,  and  the 
other  into  water,  which  exhibited  an  alternate  elevation  and  depression  with 
inspiration  and  expiration ;  this  has  been  repeated  and  confirmed  by  several 
Physiologists.  On  the  other  hand,  the  expiratory  movement,  while  it  directly 


MOTION   OF   THE   BLOOD   IN   THE   VEINS.  499 

causes  accumulation  in  the  veins,  will  assist  the  heart  in  propelling  the  blood 
into  the  arteries  ;  and  by  the  combined  action  of  these  two  causes  is  produced, 
among  other  effects,  the  rising  and  sinking  of  the  Brain,  synchronously  with 
expiration  and  inspiration,  which  are  observed  when  a  portion  of  the  cranium 
is  removed.  Several  considerations,  however,  agree  in  pointing  to  the  conclu- 
sion that  no  great  efficacy  can  be  rightly  attributed  to  the  Respiratory  move- 
ments, as  exerting  any  general  influence  over  the  Venous  circulation.  The 
Pulmonary  circulation,  being  entirely  within  the  chest,  cannot  be  affected  by 
variations  in  atmospheric  pressure ;  the  entire  venous  circulation  of  the  foetus, 
also,  is  independent  of  any  such  agency.  Again,  it  has  been  shown  experi- 
mentally by  Dr.  Arnott  and  others,  that  no  suction-power  exerted  at  the  farther 
end  of  a  long  tube,  whose  walls  are  so  deficient  in  firmness  as  are  those  of  the 
Veins,  can  occasion  any  acceleration  in  a  current  of  fluid  transmitted  through 
it ;  for  the  effect  of  the  suction  is  destroyed,  at  no  great  distance  from  the  point 
at  which  it  is  applied,  by  the  flapping  together  of  the  sides  of  the  vessels. — One 
of  the  most  powerful  of  the  general  causes  which  influence  the  Venous  circula- 
tion is  doubtless  the  frequently-recurring  pressure  of  the  muscles  upon  their 
trunks.  In  every  instance  that  Muscular  movement  takes  place,  a  portion  of 
the  Veins  of  the  part  will  undergo  compression ;  and  as  the  blood  is  prevented, 
by  the  valves  in  the  veins,  from  being  driven  back  into  the  small  vessels,  it  is 
necessarily  forced  on  towards  the  heart.  As  each  set  of  muscles  is  relaxed, 
the  veins  compressed  by  it  fill  out  again,  to  be  again  compressed  by  the  renewal 
of  the  force.  That  the  general  Muscular  movement  is  an  important  agent  in 
maintaining  the  circulation,  at  a  point  above  that  at  which  it  would  be  kept  by 
the  action  of  the  heart  and  vascular  system  alone,  appears  from  several  con- 
siderations. The  pulsations  are  diminished  in  frequency  by  rest,  accelerated 
by  exertion,  and  very  much  quickened  by  violent  effort  (§  511,  d^).  In  all  kinds 
of  exercise,  and  in  almost  every  sort  of  effort,  there  is  that  alternate  contraction 
and  relaxation  of  particular  groups  of  Muscles  which  has  been  just  mentioned 
as  affecting  the  flow  of  blood  through  the  veins ;  and  there  can  be  little  doubt 
that  the  increased  rapidity  of  the  return  of  blood  through  them  is  of  itself  a 
sufficient  cause  for  the  accelerated  movements  of  the  heart.  When  a  large 
number  of  muscles  are  put  in  action  after  repose,  as  is  the  case  when  we  rise  up 
from  a  recumbent  or  a  sitting  posture,  the  blood  is  driven  to  the  heart  with  a 
very  strong  impetus;  and  if  that  organ  should  be  diseased,  it  may  arrive  there 
in  a  quantity  larger  than  can  be  disposed  of;  so  that  sudden  death  may  be  the 
result.  Hence  the  necessity  for  the  avoidance  of  all  sudden  and  violent  move- 
ments, on  the  part  of  those  who  labor  under  either  a  functional  or  structural 
disease  of  the  centre  of  the  circulation. 

532.  The  Venous  circulation  is  much  more  liable  than  the  Arterial,  to  be 
influenced  by  the  force  of  Gravity  ;  and  this  influence  is  particularly  noticeable, 
when  the  tonicity  of  the  vessels  is  deficient. — The  following  experiments  per- 
formed by  Dr.  C.  J.  B.  Williams,1  to  elucidate  the  influence  of  deficient  firm- 
ness in  the  walls  of  the  vessels,  and  of  gravitation,  over  the  movement  of  fluids 
through  tubes,  *throw  great  light  on  the  causes  of  venous  congestion.  A  tube 
with  two  equal  arms  having  been  fitted  to  a  syringe,  a  brass  tube  two  feet  long, 
having  several  right  angles  in  its  course,  was  adapted  to  one  of  them,  whilst  to 
the  other  was  tied  a  portion  of  a  rabbit's  intestine  four  feet  long,  and  of  caliber 
double  that  of  the  brass  tube,  this  being  arranged  in  curves  and  coils,  but  with- 
out angles  and  crossings.  When  the  two  tubes  were  raised  to  the  same  height, 
the  small  metal  tube  discharged  from  two  to  five  times  the  quantity  of  water  dis- 
charged in  a  given  time  by  the  larger  but  membranous  tube;  the  difference 
being  greatest  when  the  strokes  of  the  piston  were  most  forcible  and  sudden,  by 

1  "Principles  of  Medicine,"  3d  Am.  Ed.,  156. 


500  OF   THE   CIRCULATION    OF   THE   BLOOD. 

which  the  intestine  was  much  dilated  at  its  syringe-end,  but  conveyed  very 
little  more  water.  When  the  discharging  ends  were  raised  a  few  inches  higher, 
the  difference  increased  considerably,  the  amount  of  fluid  discharged  by  the  gut 
being  much  diminished  ;  and  when  the  ends  were  raised  to  the  height  of  eight 
or  ten  inches,  the  gut  ceased  to  discharge,  each  stroke  only  moving  the  column 
of  water  in  it,  and  this  subsiding  again,  without  rising  high  enough  to  overflow. 
When  the  force  of  the  stroke  increased,  the  part  of  the  intestine  nearest  the 
syringe  burst. — From  these  experiments  it  is  easy  to  understand  how  any  de- 
ficiency of  "tone"  in  the  Venous  system  will  tend  to  prevent  the  ascent  of  the 
blood  from  the  depending  parts  of  the  body,  and  will  consequently  occasion  an 
increased  pressure  on  the  walls  of  the  vessels,  and  an  augmentation  in  the  quan- 
tity of  blood  they  contain.  All  these  conditions  are  peculiarly  favorable  to  the 
escape  of  the  watery  part  of  the  blood  from  the  small  vessels ;  and  this  may 
either  infiltrate  into  the  areolar  tissue,  or  it  may  be  poured  into  some  neighbor- 
ing serous  cavity,  producing  dropsy.  Thus  it  happens  that  such  effusions  may 
often  be  traced  to  that  state  of  deficient  vigor  of  the  system  which  peculiarly 
manifests  itself  in  want  of  tone  of  the  bloodvessels;  and  that  it  is  relieved  by 
remedies  which  restore  this.  In  many  young  females  of  leucophlegmatic  tem- 
perament, for  example,  there  is  a  tendency  to  swelling  of  the  feet,  by  redema- 
tous  effusion  into  the  areolar  tissue,  in  consequence  of  the  depending  position  of 
the  limbs;  the  O3dema  disappears  during  the  night,  but  returns  during  the  day, 
and  is  at  its  maximum  in  the  evening.  And  the  congestion  which  frequently 
manifests  itself  in  the  posterior  parts  of  the  body,  towards  the  close  of  exhaust- 
ing diseases,  in  which  the  patient  has  lain  much  upon  his  back,  is  attributable  to 
a  similar  cause ;  of  such  congestion,  effusions  into  the  various  serous  cavities  are 
frequent  results ;  and  such  effusions,  taking  place  during  the  last  hours  of  life, 
are  often  erroneously  regarded  as  the  cause  of  death.  To  the  same  cause  we 
are  to  attribute  the  varicose  state  of  the  veins  of  the  leg,  which  is  so  common 
amongst  persons  of  relaxed  fibre,  and  especially  in  those  whose  habits  require 
them  to  be  much  in  the  erect  posture ;  and  this  distension  occasionally  proceeds 
to  complete  rupture,  the  causes  of  which  are  fully  elucidated  by  the  experiments 
just  cited. 

6. — Peculiarities  of  the  Circulation  in  different  Parts. 

533.  In  several  portions  of  the  Human  body,  there  are  certain  varieties  in 
the  distribution  and  in  the  functional  actions  of  the  bloodvessels,  which  should 
not  be  omitted  in  a  general  account  of  the  Circulation. — Of  these,  we  have  in 
the  first  place  to  notice  the  apparatus  for  the  Pulmonary  circulation  ;  the  chief 
peculiarity  of  which  is,  that  venous  blood  is  sent  from  the  heart,  through  a  tube 
which  is  arterial  in  its  structure,  whilst  arterial  blood  is  returned  to  the  heart, 
through  a  vessel  whose  entire  character  is  that  of  a  vein.  The  movement  of 
the  blood  through  these  is  considerably  affected  by  the  physical  state  of  the 
lungs  themselves ;  being  retarded  by  any  causes  which  can  occasion  pressure  on 
the  vessels  (such  as  over-distension  of  the  cells  with  air,  obsk-uction  of  their 
cavity  by  solid  or  fluid  depositions,  or  by  foreign  substances  injected  into  them, 
&c.) ;  and  proceeding  with  the  greatest  energy  and  regularity,  when  the  respira- 
tory movements  are  freely  performed. — The  Portal  circulation,  again,  is  pecu- 
liar, in  being  a  kind  of  offset  from  the  general  or  systemic  circulation,  and  also 
in  being  destitute  of  valves  ;  and  it  may  be  surmised  with  much  probability,  that 
the  purpose  of  their  absence  is,  to  allow  of  an  unusually  free  passage  of  blood 
from  one  part  of  that  system  to  another,  during  the  very  varying  conditions  to 
which  it  is  subjected  (§  490). — Another  very  important  modification  of  the 
Circulating  system  is  that  which  presents  itself  within  the  Cranium.  From 
the  circumstance  of  the  cranium  being  a  closed  cavity,  which  must  be  always 


PECULIARITIES   OF   CIRCULATION.  501 

filled  with  the  same  total  amount  of  contents,  the  flow  of  blood  through  its  ves- 
sels is  attended  with  some  peculiarities.  The  pressure  of  the  atmosphere  is 
here  exerted,  rather  to  keep  the  blood  in  the  head,  than  to  force  it  out ;  and  it 
might  accordingly  be  inferred  that,  whilst  the  quantity  of  cerebral  matter  re- 
mains the  same,  the  amount  of  blood  in  the  cranial  vessels  must  also  be  invari- 
able. This  inference  appeared  to  derive  support  from  the  experiments  of  Dr. 
Kellie.1  On  bleeding  animals  to  death,  he  found  that,  whilst  the  remainder  of 
the  body  was  completely  exsanguine,  the  usual  quantity  of  blood  remained  in 
the  arteries  and  veins  of  the  cranium ;  but  that,  if  an  opening  was  made  in  the 
skull,  these  vessels  were  then  as  completely  emptied  as  the. rest.  It  is  not  to  be 
hence  inferred,  however,  that  the  absolute  quantity  of  blood  within  the  cranium 
is  not  subject  to  variation ;  and  that  in  the  states  of  inflammation,  congestion, 
or  other  morbid  affections,  there  is  only  a  disturbance  of  the  usual  balance  of 
the  arterial  and  venous  circulation.  The  fact  in  all  probability  is  rather,  that 
the  softness  of  the  Cerebral  tissue,  and  its  varying  functional  activity,  render  it 
peculiarly  liable  to  undergo  alterations  in  bulk;  and  that  the  amount  of  the 
" cerebro-spinal  fluid"  varies  considerably  at  different  times;  so  that  the  quan- 
tity of  blood  may  thus,  even  in  the  healthy  condition,  be  continually  changing. 
Moreover,  in  disordered  states  of  the  circulation,  the  quantity  of  blood  in  the 
vessels  of  the  cranium  may  be  for  a  time  diminished  by  a  sudden  extravasation, 
either  of  blood  or  serum,  into  the  cerebral  substance ;  and  the  amount  of  interior 
pressure  upon  the  walls  of  the  vessels  may  also  be  considerably  altered,  even 
when  there  is  no  difference  in  the  quantity  of  fluid  contained  in  them.3 

534.  The  Erectile  tissues  constitute  another  curious  modification  of  the  ordi- 
nary vascular  apparatus.  The  chief  of  these  are  the  corpora  cavernosa  in  the 
penis  of  the  male,  and  in  the  clitoris  of  the  female ;  the  collection  of  similar  tissues 
round  the  vagina,  and  in  the  nymphse,  of  the  female;  and  the  nipple  in  both 
sexes.  In  all  these  situations,  erection  may  be  produced  by  local  irritation ;  or 
it  may  take  place  as  a  result  of  certain  emotional  conditions  of  the  mind ;  the 
influence  of  which  is  probably  transmitted  through  the  Sympathetic  nerve,  as 
it  may  be  experienced  even  in  cases  of  paraplegia.  The  erectile  tissue  appears 
essentially  to  consist  of  a  plexus  of  veins  with  varicose  enlargements,  inclosed 
in  a  fibrous  envelop  with  trabecular  partitions.  This  envelop,  according  to 
the  recent  researches  of  Prof.  Kb'lliker,  contains  a  large  amount  of  non-striated 
muscular  fibre ;  the  contraction  of  which  is  doubtless  in  some  way  concerned  in 
the  result.  In  the  penis,  as  first  pointed  out  by  Prof.  Miiller,  there  are  two  sets 
of  arteries ;  those  of  one  set,  destined  for  the  nutrition  of  the  tissues,  commu- 
nicating with  the  veins  in  the  usual  way,  through  a  capillary  network  ;  whilst' 
the  others,  termed  by  him  the  "  helicine  arteries,"  are  short  tendril-like  branches, 
which  project  into  the  veins  (covered,  however,  by  their  lining  membrane), 
sometimes  singly,  and  sometimes  in  tufts,  ending  abruptly  by  dilated  extremities. 
It  was  maintained  by  Miiller  that  the  dilated  ends  of  these  helicine  arteries 
open  into  the  venous  cavities ;  but  no  distinct  apertures  have  been  seen  in  them ; 
and  it  seems  more  probable  that  (as  Miiller  himself  admits)  they  are  merely 
arterial  diverticula,  the  distension  of  which  concurs  with  that  of  the  venous 
areol93,  in  the  act  of  erection. — The  proximate  cause  of  the  erection  of  the 
penis  has  been  stated  by  some  to  be  the  action  of  the  ischio-cavernosi  muscles; 
and  by  others  it  has  been  attributed  to  the  compression  of  the  vena  dorsalis 
penis  against  the  symphysis  pubis.  But  although  these  muscles  probably  afford 
assistance  in  completing  and  strengthening  the  erection,  it  is  obvious  that  no 
analogous  power  can  be  exerted  in  other  erectile  organs,  the  nipple,  for  example. 

1  "Edinburgh  Medico-Chirurgical  Transactions,"  vol.  i. 

2  The  results  of  the  more  recent  experiments  of  Dr.  G.  Burrows  ("Medical  Gazette," 
April  and  May,  1843)  fully  confirm  the  views  stated  above. 


502  OF   RESPIRATION. 

— It  is  maintained  by  Prof.  Kblliker  that  the  office  of  the  muscular  fibres  which 
pass  in  every  direction  amongst  the  dilated  veins,  is  to  keep  them  compressed 
in  the  intervals  of  erection,  so  as  to  prevent  them  from  being  distended  by  the 
vis  a  tergo  of  the  blood ;  and  that  the  stimulus  to  erection,  which  is  usually 
conveyed  through  the  nervous  system,  so  operates  upon  these  fibres  as  to  occa- 
sion their  relaxation,  whereby  the  free  distension  of  the  cavernous  veins  and  of 
the  arterial  diverticula  is  permitted.  He  refers,  moreover,  to  the  excessive  con- 
traction of  erectile  organs  which  is  induced  by  cold,  and  to  the  effect  of  warmth- 
in  favoring  their  enlargement,  as  confirmatory  of  this  view;  and  considers  that 
no  other  agency  is  required.1 


CHAPTER  X. 

OF   RESPIRATION. 

1. — Nature  of  the  Function  :  and  Provisions  for  its  Performance. 

535.  THE  Nutritive  fluid,  in  its  circulation  through  the  capillaries  of  the 
system,  undergoes  great  alterations,  both  in  its  physical  constitution  and  in  its 
vital  properties.  It  gives  up  to  the  tissues  with  which  it  is  brought  into  con- 
tact, some  of  its  most  important  elements ;  and  at  the  same  time,  it  is  made  the 
vehicle  of  the  removal,  from  these  tissues,  of  ingredients  which  are  no  longer 
in  the  state  of  combination  that  fits  them  for  their  offices  in  the  Animal  Economy. 
To  separate  these  ingredients  from  the  general  current  of  the  circulation,  and 
to  carry  them  out  of  the  system,  is  the  great  object  of  the  Excretory  organs; 
and  it  is  very  evident  that  the  importance  of  their  respective  functions  will  vary 
with  the  amount  of  the  ingredient  which  they  have  to  separate,  and  with  the 
deleterious  influence  which  its  retention  would  exert  on  the  welfare  of  the  sys- 
tem at  large.  Of  all  these  injurious  ingredients,  Carbonic  Acid  is  without 
doubt  the  one  most  abundantly  introduced  into  the  nutritive  fluid ;  and  it  is  also 
most  deleterious  in  its  effects  on  the  system,  if  allowed  to  accumulate. — We  find, 
accordingly,  that  the  provision  for  the  removal  of  this  substance  from  the  blood, 
is  one  of  peculiar  extent  and  importance,  especially  in  the  higher  forms  of 
animals;  and  further,  that  instead  of  being  effected  by  an  operation  peculiarly 
vital  (like  other  acts  of  Excretion),  its  performance  is  secured  by  being  made 
to  depend  upon  simple  physical  conditions,  and  is  thus  comparatively  little  sus- 
ceptible of  derangement  from  disorder  of  other  processes.  All  that  is  requisite 
for  it,  is  the  exposure  of  the  Blood  to  the  influence  of  the  Atmospheric  air  (or, 
in  aquatic  animals,  of  air  dissolved  in  water),  through  the  medium  of  a  mem- 
brane that  shall  permit  the  " diffusion  of  gases;"  an  interchange  then  taking 
place  between  the  gaseous  matters  on  the  two  sides — Carbonic  acid  being  exhaled 
from  the  Blood,  and  being  replaced  by  Oxygen  from  the  air.  Thus  the  extri- 
cation of  Carbonic  acid  is  effected  in  a  manner  that  renders  it  subservient  to  the 
introduction  of  that  element  which  is  required  for  all  the  most  active  manifesta- 
tions of  vital  power ;  and  it  is  in  these  two  processes  conjointly,  not  in  either 
alone,  that  the  function  of  Respiration  essentially  consists. — We  shall  now 

1  See  his  essay  "Das  Anatomisclie  und  Physiologische  Verhalten der  Cavernoser  Korper 
der  Sexual  organe,"  1851  ;  cited  in  Paget  and  Kirkes's  "  Handbook  of  Physiology,"  2d 
edit.,  p.  145. — It  is  rather  difficult  to  admit  the  power  of  nerves  to  cause  relaxation  of 
muscles,  which  this  hypothesis  requires  ;  and  also  to  explain  in  accordance  with  it  the  fact 
of  very  familiar  occurrence,  that  the  application  of  moderate  cold  (as  in  putting  on  a  clean 
shirt)  frequently  occasions  erection  of  the  male  nipple. 


GENERAL    STRUCTURE   OF   THE   RESPIRATORY   ORGANS.  503 

inquire  into  the  sources  from  which  Carbonic  acid  is  produced  in  the  living  body, 
and  the  causes  of  the  demand  for  Oxygen. 

536.  It  has  been  shown  (CHAP,  in.)  that  the  vital  activity  of  the  organism  at 
large  involves  a  continual  change  in  its  constituent  parts ;  and  that  those  which  (so 
to  speak)  live  the  fastest,  usually  die  the  soonest,  and  pass  most  readily  into 
decay.     Hence  in  the  very  performance  of  the  Organic  functions  which  concur 
to  effect  the  Nutrition  of  the  body,  there  is  a  constant  source  of  disintegration  ; 
and  one  of  the  chief  products  of  the  decay  of  the  tissues,  which  is  consequent 
upon  their  loss  of  vitality,  is  Carbonic  acid. — Thus  the  most  general  object  of 
the  Respiratory  process,  which  is  common  to  all  forms  of  organized  being,  is 
the  extrication  of  this  product  from  the  system ;   and  the  demand  for  aeration 
hence  arising  will  vary  with  the  activity  of  the  nutritive  operations.     Now  the 
rate  of  life,  and  consequently  the  amount  of  disintegration,  in  an$  organized 
structure,  depend  in  great  measure  upon  the  temperature  at  which  it  is  main- 
tained (§§  123,  127);  and  thus  it  happens  that  the  production  of  Carbonic  acid 
from  this  source,  at  the  ordinary  rate  of  vital  activity,  is  much  more  rapid  in 
"warm-blooded"  than  in  "  cold-blooded"  animals,  and  that  the  former  suffer  far 
more  speedily  than  the  latter  from  the  privation   of  air.     But  when  the  tem- 
perature of  the  Reptile  is  raised  by  external  heat  to  the  level  of  that  of  the 
Mammal,  its  need  for  respiration  increases,  owing  to  the  augmented  waste  of  its 
tissues.     When,  on  the  other  hand,  the  warm-blooded  Mammal  is  reduced,  in 
the  state  of  hybernation,  to  the  level  of  the  cold-blooded  Reptile,  the  waste  of 
its  tissues  diminishes  to  such  an  extent,  as  to  require  but  a  very  small  exertion 
of  the  respiratory  process  to  get  rid  of  the  carbonic  acid,  which  is  one   of  its 
chief  products.      And  in  those  animals  which  are  capable  of  retaining  their 
vitality  when  they  are  frozen,  or  when  their  tissues  are  completely  dried  up, 
vital  activity  and  disintegration  are  alike  entirely  suspended,  and  consequently 
there  is  no  carbonic  acid  to  be  set  free. 

537.  But  another  source  of  Carbonic  acid  to  be  set  free  by  the  Respiratory 
process,  and  one  which  is  peculiar  to  animals,  consists  in  the  rapid  changes 
which  take  place  in  the  Muscular  and  Nervous  tissues,  in  the  very  act  of  per- 
forming their  peculiar  functions  ]  the  development  of  the  Muscular  and  of  the 
Nervous  forces  involving,  as  the  very  condition  of  their  production,  a  change  in 
the  substance  of  these  tissues  respectively ;  in  which  change  a  large  quantity  of 
Oxygen  is  consumed,  and  a  large  amount  of  Carbonic  acid  is  generated.    Hence 
in  Man,  as  in  all  Animals  in  which  the  Nervo-Muscular  apparatus  constitutes 
the  essential  part  of  the  organism,  a  powerful  demand  for  Respiration  is  created 
by  its  activity ;  the  amount  of  oxygen  taken  in,  and  of  carbonic  acid  exhaled, 
being  determined,  cxteris  paribus,  by  the  degree  in  which  this  apparatus  is 
exercised. 

538.  Besides  these  sources  of  Carbonic  acid  which  are  common  to  all  Animals, 
there  is  another  which  is  restricted  (or  nearly  so)  to  the  two  highest  classes, 
Birds  and  Mammals  ;  these  being  distinguished  by  their  power  of  maintaining 
a  constantly  elevated  temperature.     A  part  of  this  Heat  is  generated  by  the 
oxygenation  of  the  components  of  their  disintegrating  tissues,  the  metamorphosis 
of  which  takes  place  at  a  very  rapid  rate ;  but  where  this  is  not  sufficient,  their 
power  of  maintaining  their  temperature  depends  upon  the  direct  combination  of 
certain  elements  of  the  food  with  the  oxygen  of  the  air,  by  the  combustive  pro- 
cess.— The  quantity  of  carbonic  acid  that  is  generated  directly  from  the  elements 
of  the  food  seems  to  vary  considerably  in  different  animals,  and  in   different 
states  of  the   same  individual.     In  the   Carnivorous  tribes,  which  spend  the 
greater  part  of  their  time  in  a  state  of  activity,  it  is  probable  that  the  quantity 
which  is  generated  by  the  waste  or  metamorphosis  of  the  tissues  is  sufficient  for 
the  maintenance   of  the  required  temperature ;  and  that  little  or  none  of  the 
carbonic  acid  set  free  in  respiration  is  derived  from  the  direct  combustion  of  the 


504 


OF   RESPIRATION. 


materials  of  the  food.  But  in  Herbivorous  animals  of  comparatively  inert  habits, 
the  amount  of  metamorphosis  of  the  tissues  is  far  from  being  sufficient ;  and  a 
large  part  of  the  food,  consisting  as  it  does  of  substances  that  cannot  be  applied 
to  the  nutrition  of  the  tissues,  is  made  to  enter  into  direct  combination  with  the 
oxygen  of  the  air,  and  thus  to  compensate  for  the  deficiency.  In  Man  and 
other  animals,  which  can  sustain  considerable  variations  of  climate,  and  can 
adapt  themselves  to  a  great  diversity  of  habits,  the  quantity  of  carbonic  acid 
formed  by  the  direct  combination  of  the  elements  of  the  food  with  the  oxygen 
of  the  air,  will  differ  extremely  under  different  circumstances  (§  402.)  It  will 
serve  as  the  complement  of  that  which  is  formed  in  other  ways ;  so  that  it  will 
diminish  with  the  increase,  and  will  increase  with  the  diminution,  of  muscular 
activity.  It  will  also  vary  in  an  inverse  ratio  to  the  external  temperature,  in- 
creasing w?.th  its  diminution  (as  more  heat  must  then  be  generated),  and  dimin- 
ishing with  its  increase ;  the  effect  of  external  heat  being  thus  precisely  opposite, 
in  the  warm-blooded  animal,  to  that  which  it  exerts  on  the  cold-blooded  (§  586). 
— In  all  cases,  if  a  sufficient  supply  of  food  be  not  furnished,  the  store  of  fat  is 
drawn  upon  ;  and  if  this  be  exhausted,  the  animal  dies  of  cold  (§  416). 

539.  To  recapitulate,  then,  the  sources  of  Carbonic  Acid  in  the  animal  body 
are  threefold. — 1.  The  continual  decay  of  the  tissues  common  to  all  organized 
bodies,  which  is  favored  by  all  that  promotes  their  vital  activity,  and  retarded 
by  every  influence  that  depresses  it. — 2,  The  metamorphosis  peculiar  to  the 
Nervous  and  Muscular  tissues,  which  is  the  very  condition  of  the  production  of 
their  power,  and  which  therefore  bears  a  direct  relation  to  the  degree  in  which 
they  are  exerted. — 3.  The  direct  conversion  of  the  carbon  and  hydrogen  of  the 
food  into  carbonic  acid  and  water,  which  is  peculiar  to 
warm-blooded  animals ;  and  which  varies  in  quantity,  in 
accordance  with  the  amount  of  heat  to  be  generated. 

540.  The  wonderful  nature  of  the  structural  arrange- 
ments which  are  made  for  the  aeration  of  the  blood  in  Man 
(as  in  Mammalia  generally),  and  the  completeness  of  the 
provisions  whereby  these  are  put  into  active  operation, 
will  be  best  understood,  if,  for  the  sake  of  contrast,  we  first 
bestow  a  brief  survey  on  the  Pulmonary  apparatus  of  Rep- 
tiles ;  a  class  in  which  the  demand  for  respiration  is  re- 
duced to  a  comparatively  low  grade,  by  the  absence  of  any 
necessity  for  the  maintenance  of  an  independent  tempera- 
ture, by  the  general  torpor  of  their  habits  (whence  arises 
a  very  small  amount  of  "  waste"  in  the  nervo-muscular 
apparatus),  and  by  the  very  slow  rate  at  which  their  or- 
ganic functions  are  performed,  and  the  life  of  the  whole 
body  is  carried  on. — The  lungs  of  Reptiles  are,  for  the 
most  part,  simple  sacs ;  into  which  the  bronchial  tubes 
open  freely,  and  on  the  walls  of  which  the  pulmonary  ves- 
sels are  distributed.  The  extent  of  surface  is  considerably 
increased,  however,  by  the  formation  of  a  number  of  little 
pits  or  sacculi  on  the  inner  wall  of  the  cavity,  especially 
at  its  upper  part ;  and  between  these  we  observe  a  sort  of 
cartilaginous  framework,  which  is  continuous  with  the 
cartilage  of  the  bronchus  on  either  side.  Thus  it  happens 
that  the  network  of  pulmonary  capillaries  is  exposed  only 
on  one  side  to  the  influence  of  the  air.  The  general  dis- 
tribution of  these  vessels  is  shown  in  the  accompanying 
figures.  It  will  be  seen  that  the  trunk  of  the  pulmonary 
artery  runs  along  one  side  of  the  sac,  and  that  of  the  pulmonary  vein  along  the 


Fig.  141f. 

*       i 


I--4 


1 


Lung  of  Triton  criftatus, 
magnified  about  3  ilium.; 
— a,  pulmonary  artery ;  b, 
pulmonary  vein. 


GENERAL    STRUCTURE   OF   THE    RESPIRATORY   ORGANS. 


505 


Fig.  142. 


other  (Fig.  141f) ;  and  that  numerous  branches  arise  from  the  former,  which 
subdivide  into  capillaries  that  ramify  over  the  whole 
surface,  and  then  reunite  into  small  veins  which  termi- 
nate in  the  latter.  The  islets  of  parenchyma  left  be- 
tween the  capillary  vessels  are  seen  to  be  much  smaller 
than  those  which  are  usually  to  be  observed  in  the  sys- 
temic circulation  (Figs.  142,  143) ;  so  that  the  mem- 
brane is  more  copiously  traversed  by  vessels,  than  almost 
any  other  that  is  known.  The  walls  of  the  capillaries, 
moreover,  are  much  less  distinct  than  those  of  the  sys- 
temic circulation.  These  two  conditions  are  obviously 
favorable  to  the  exposure  of  the  largest  possible  quantity 
of  blood  to  the  influence  of  the  air ;  but  as  the  surface 
is  not  an  extensive  one,  the  amount  which  can  be  thus 
exposed  at  any  one  time  is  very  limited ;  and  the  pul- 
monary artery  is  often,  in  fact,  like  one  of  the  smaller 
branches  of  the  aorta,  which  trunk  conveys  a  mixed 
fluid  to  the  system  at  large. — The  lungs  of  Reptiles  are 
not,  like  those  of  Mammals,  enclosed  in  a  distinct  cavity 
partitioned  off  from  the  abdominal  by  the  interposition 
of  a  diaphragm  ;  but  they  lie  in  immediate  contact  with 
the  other  viscera ;  and  the  mechanism  of  inspiration  and 
expiration  is  consequently  far  less  complete,  than  it  is  in  animals  which  possess 
a  muscular  diaphragm  closing  in  the  floor  of  the  thoracic  cavity,  and  capable, 

Fig.  143. 


Portion  of  the  Lung  of  Tri- 
ton, more  highly  magnified ; 
the  vessels,  finely  injected 
with  size  and  vermilion,  form 
a  network  so  minute,  that  the 
parenchyma  is  only  seen  in 
small  islets  in  its  interstices. 


Portion  of  the  Lung  of  a  living  Triton,  as  seen  under  the  microscope  with  the  power  of  150  diameters 
a,  b,  pulmonary  vein,  receiving  blood  from  the  large  trunk  c,  and  a  smaller  vessel  d. 


506  OF  RESPIRATION. 

by  its  contraction,  of  largely  increasing  the  capacity  of  that  cavity.  In  fact,  many 
Reptiles  are  incapable  of  draining  in  air,  and  can  only  force  it  in  by  a  process 
resembling  deglutition.1 

541.  The  size  of  the  Lungs  in  Man  and  the  Mammalia  is  far  smaller  in  propor- 
tion to  their  bulk,  than  it  is  in  most  Reptiles ;  but  this  diminution  is  more  than 
compensated  by  the  minute  subdivision  of  their  cavities,  by  the  peculiarity  of  the 
distribution  of  their  bloodvessels,  and  by  the  arrangements  whereby  a  continual 
and  rapid  interchange,  both  of  the  blood  and  the  air,  is  provided  for. — The  fol- 
lowing are  the  points  of  most  importance  in  the  structure 
Fig.  143*.  Of  the  Human  Lung.2    The  walls  of  the  bronchial  tubes  con- 

tain distinct  longitudinal  and  circular  layers  of  fibrous  struc- 
ture ;  but  the  latter  alone,  according  to  Prof.  Kolliker,  con- 
tain muscular  fibre-cells.  [The  muscular  fibres  which  exist 
in  the  trachea  are  continued  down  even  to  the  terminal  bron- 
chi, but  instead  of  filling  up  the  gap  in  the  cartilaginous 
framework,  posteriorly,  as  in  'the  trachea,  they  form  a  uni- 
form layer  encircling  the  canal,  but  excessively  thin.  Fig. 
143*. — ED.]  These  tubes  divide  and  subdivide,  like  the 
branches  of  a  tree,  still  retaining  their  ordinary  characters, 
until  they  are  no  more  than  from  l-50th  to  1-3 Oth  of  an 

Small    bronchial    tube      •      i_  •      »«  i   •      ,1  ,11          -TT         i  i 

laid  open,  showing  the  incn  m  diameter ;  and  in  these  the  longitudinal  and  annular 

transverse  piexiform  ar-  fibres,  together  with  the  ciliated  epithelium,  come  to  an 

rangement  of  the  muscu-  abrupt  termination.     Beyond  this  boundary,  the  tubular 

iar  layer,  and  its  disposi-  form  Of  the  air-passages  continued  from   the  bronchi  is 

tion  at  the  orifice  of  a  retaine(j  for  some  distance:  but  it  is  gradually  changed  by 

branch.    From  a  man  set.      .*      •  i         •>  i  /..{  D         111- 

fifty.  Magnified  2  diam.  *ne  irregular  branches  ot  the  passages,  and  by  the  increase 
From  Todd  <&  Bowman,  of  the  number  of  apertures  in  their  walls,  which  lead  to  the 
air-vesicles.  Thus,  at  last,  each  minute  division  of  the  air- 
passages  becomes  quite  irregular  in  form  ;  air-vesicles  opening  into  every  part 
of  it,  and  almost  constituting  its  walls;  until  it  terminates,  almost  without 
dilatation,  in  an  air-vesicle.  This  terminal  portion  of  the  air-passage,  with 
its  surrounding  cluster  of  air-vesicles,  may  be  regarded  as  forming  a  sort  of 
lobule,  and  as  representing  the  entire  lung  of  a  Frog  or  other  Reptile;  the 
whole  lung  of  the  Mammal  being  made  up  of  a  multitude  of  such  lobules, 
which  are  almost  exact  repetitions  of  each  other.  Those  vesicles  which  com- 
municate directly  with  the  bronchial  tubes  and  intercellular  passages,  open 
into  them  by  large  circular  apertures ;  and  they  are  themselves  similarly 
opened  into  by  other  vesicles,  which  again  communicate  with  others  beyond 
them ;  so  that  each  of  the  openings  in  the  air-passage  leads  to  a  series  of  air- 
vesicles  extending  from  it  to  the  surface  of  the  lobule.  The  vesicles  which 
communicate  most  directly  with  the  air-passages,  are  more  minute,  and  have 
a  closer  vascular  network,  than  those  which  lie  nearer  the  surface  of  the  lobule  ; 
an  arrangement  which  is  in  beautiful  harmony  with  the  relative  facility  of  reno- 
vation of  the  air  which  they  respectively  contain.  The  air-vesicles  have  also 
lateral  apertures  into  each  other ;  so  that  all  the  parts  of  any  one  lobule  freely 
communicate  together.  The  walls  of  the  air-vesicles  are  formed  of  a  very  thin 
and  transparent  membrane,  which  is  folded  sharply  at  the  orifices  of  communi- 
cation, so  as  to  form  a  very  definite  border  to  them  ;  and  which  is  lined  by  an 
epithelial  layer,  composed  of  minute  polygonal  cells  of  from  l-1600th  to  1 -2250th 
of  an  inch  in  diameter,  and  from  l-2800th  to  l-3800th  of  an  inch  in  thickness 
(Kolliker).  This  lining  membrane  is  distinctly  fibrous ;  and  its  fibres  are  par- 

1  See  "Prin.  of  Phys.,  Gen.  and  Comp.,"  g§  324r,  526,  527,  Am.  Ed. 

2  See  especially  the  Memoir  by  Mr.  Rainey  in  the  "  Med-Chirurg.  Trans.,"  vol.  xxviii. 


GENERAL    STRUCTURE    OF   THE   RESPIRATORY   ORGANS. 


507 


ticularly  strong  and  well  marked  around  the  apertures  of  communication  between 
the  contiguous  air-cells.  These  fibres  have  not  any  resemblance  to  muscular 
tissue;  but  rather  correspond  with  those  of  yellow  fibrous  tissue.1 — The  diame- 

Fig.  144. 


The  Larynx,  Trachea,  and  Bronchise,  deprived  of  their  fibrous  covering,  and  with  the  outline  of  the  Lungs : 
1, 1,  outline  of  the  upper  lobes  of  the  lungs;  2,  outline  of  the  middle  lobe  of  the  right  lung ;  3,  3,  outline  of 
the  inferior  lobes  of  both  lungs ;  4,  outline  of  the  ninth  dorsal  vertebra,  showing  its  relation  to  the  lungs  and 
the  vertebral  column;  5,  thyroid  cartilage;  6,  cricoid  cartilage;  7,  trachea;  8,  right  bronchus;  9,  left  bron- 
chus; 10,  crico-thyroid  ligament;  11,  12,  rings  of  the  trachea;  13,  first  ring  of  the  trachea;  14,  last  ring  of 
the  trachea,  which  is  corset-shaped;  15, 16,  a  complete  bronchial  cartilaginous  ring;  17,  one  which  is  bifur- 
cated ;  18,  double  bifurcated  bronchial  rings ;  19, 19,  smaller  bronchial  rings ;  20,  depressions  for  the  course 
of  the  large  bloodvessels. 

ter  of  the  Human  air-cells  is  about  twenty  times  greater  than  that  of  the  capil- 
laries which  are  distributed  upon  their  parietes ;  varying  (according  to  the 
measurement  of  Weber)  from  the  l-200th  to  the  l-70th  of  an  inch.2  It  has 
been  calculated  by  M.  Rouchoux,  that  as  many  as  17,790  air-cells  are  grouped 
around  each  terminal  bronchus ;  and  that  their  total  number  amounts  to  no  less 
than  600  millions.  The  capillary  plexus  is  so  disposed  between  the  two  layers 
which  form  the  walls  of  two  adjacent  air-cells,  as  to  expose  one  of  its  surfaces  to 

1  It  is  suspected  by  Kolliker  that  there  may  be  muscular  fibre-cells  among  these,  as  he 
sees  long  nuclei  in  the  walls  of  the  air-vesicles.     These,  however,  are  neither  so  long  nor 
so  narrow  as  the  proper  nuclei  of  the  fibre-cells  (Fig.  22),  and  are  just  as  probably  the 
nuclei  of  capillary  bloodvessels  (Fig.  88). 

2  The  dimensions  given  by  Moleschott  ("De  Vesiculis  Pulmonum  Malpighianis")  are 
very  much  less  than  these ;  the  range  of  diameter  being  stated  by  him  at  between  1-1 20th 
and  l-1200th  of  an  inch.     The  Author's  own  observations,  however,  lead  him  to  regard 
Weber's  statement  as  very  near  the  truth;  and  that  of  Prof.  Kolliker  ("  Mikroskopische 
Anatomie,"  band.  ii.  §  196)  is  almost  precisely  the  same. 


508 


OF   RESPIRATION 
Fig.  145. 


A  view  of  the  Bronchi  and  Bloodvessels  of  the  Lungs  as  shown  by  dissection,  as  well  as  the  relative  posi- 
tion of  the  Lungs  to  the  Heart  :  1,  end  of  the  left  auricle  of  the  heart  ;  2,  the  right  auricle  ;  3,  the  left  ven- 
tricle with  its  vessels  ;  4,  the  right  ventricle  with  its  vessels;  5,  the  pulmonary  artery  ;  6,  arch  of  the  aorta; 
7,  superior  vena  cava;  8,  arteria  innominata;  9,  left  primitive  carotid  artery;  10,  left  subclavian  artery;  11, 
the  trachea  ;  12,  the  larynx  ;  13,  upper  lobe  of  the  right  lung  ;  14,  upper  lobe  of  the  left  lung;  15,  trunk  of 
the  right  pulmonary  artery  ;  16,  lower  lobes  of  the  lungs.  The  distribution  of  the  bronchi  and  of  the 
arteries  and  veins,  as  well  as  some  of  the  air-cells  of  the  lungs,  is  also  shown  in  this  dissection. 


Fig.  146. 


each;  by  which  provision  the  full  in- 
fluence of  the  air  upon  it  is  secured. 
The  network  of  vessels  (Fig.  146)  is 
close,  that  the  diameter  of  the 


so 


meshes  is  scarcely  so  great  as  that  of 
the  capillaries  which  enclose  them; 
indeed,  it  would  be  impossible  to  con- 
ceive of  a  method,  by  which  blood, 
whilst  still  retained  within  vessels, 
should  be  spread  over  a  larger  sur- 
face for  aeration.  And  if  not  re- 
stricted within  vessels,  it  could  not 
be  ceaselessly  and  rapidly  driven  on 
by  the  propulsive  power  of  the  heart, 
which  acts  no  less  efficiently  upon 
the  pulmonary  circulation  than  upon 
the  systemic,  although  the  force  ex- 

erted is  much  inferior,  the  resisting  power  being  far  less,  in  consequence  of  the 

shortness  of  the  circuit. 

[M.  Rossignol  has  recently  given  an  elaborate  description  of  the  pulmonary 


Arrangement  of  the  Capillaries  of  the  Air-cells  of  the 
Human  Lung. 


GENERAL    STRUCTURE    OF   THE   RESPIRATORY    ORGANS.  509 

Fig.  146*. 


Bronchial  termination  in 
the  lung  of  the  dog.  a. 
Tube  (lobular  passage) 
branching  towards  the  in- 
fundibula.  6.  One  of  the 
infundibula.  c.  Septa  pro- 
jecting inwards  on  the  in- 
fundibular wall  and  form- 
ing the  alveoli,  or  cells. 
From  JRossignol. 


Thin  slice  from  the  pleural  surface  of  a  cat's  lung,  considerably  magnified.  At  the  thin  edge,  bed,  alveoli 
are  seen.  In  the  centre  (as  a)  where  the  slice  is  thicker,  alveoli  are  seen  on  the  walls  of  infundibuto.  From 
Rossignol. 

structure.     He  insists  particularly  on  the  ultimate  bron-  146f. 

chial  ramifications  being  in  shape  like  an  inverted  funnel, 

and  he  terms  them  the  infundibula.     The  cells,  forming 

a  honeycomb  on  their  interior,  he  calls  the  alveoli  (Figs. 

146*  and  146f).     Emphysema,  according  to  this  author, 

seems  to  consist  in  a  distension  of  the  passages  and  cells, 

and  a  breaking  down  and  obliteration  of  the  septa,  first 

between  the  cells  of  the  same  passage  and  then  between 

neighboring    passages,    and    even    between    contiguous 

lobules. 

The  diameter  of  the  lobular  passages  is  from  y^tn  *° 
2^o-th  of  an  inch ;  and  that  of  the  cells  from  ^--^th  to  g^th 
of  an  inch  according  to  our  measurements.  In  a  prepara- 
tion of  the  lung  of  the  calf,  by  Professor  Retzius,  they 
measure  g-^th ;  and  Dr.  W.  Addison  makes  them  from 
•s^g-th  to  T *^th  of  an  inch. — ED.1] 

542.  The  fibrous  coat  of  the  bronchial  tubes  possesses  a  considerable  amount 
of  muscular  contractility,  which  (according  to  the  experiments  of  Dr.  0.  J.  B. 
Williams)3  may  be  excited  by  electrical,  chemical,  or  mechanical  stimuli,  ap- 
plied to  themselves,  but  this  is  not  so  readily  excitable  through  their  nerves, 
although  the  experiments  of  Volkmann3  and  Longet4  have  clearly  shown  the 
possibility  of  thus  calling  it  into  action.  This  contractility  resembles  that  of 
the  intestines  or  arteries,  more  than  that  of  the  voluntary  muscles  or  heart;  the 
contraction  and  relaxation  being  more  gradual  than  that  of  the  latter,  though 
less  tardy  than  that  of  the  former.  It  is  chiefly  manifested  in  the  smaller  bron- 
chial tubes,  those  of  less  than  a  line  in  diameter  having  been  seen  to  contract 
gradually  under  the  stimulus  of  galvanism,  until  their  cavity  was  nearly  obli- 
terated ;  on  the  other  hand,  in  the  trachea  and  the  larger  bronchi,  the  cartilagi- 
nous rings  prevent  any  decided  diminution  in  the  caliber  of  the  tubes,  and  the 
muscular  structure  is  much  less  distinct.  It  is  remarked  by  Dr.  Williams,  that 
the  contractility  of  the  bronchial  muscles  is  soon  exhausted  by  the  action  of  a 

1  "Physiological  Anatomy,"  by  Todd  and  Bowman,  Am.  Ed. 

2  "Report  of  the  British  Association  for  1840,"  p.  411. 

3  "Wagner's  Handworterbuch,"  art.  "Nervenphysiologie,"  $  586. 

4  "  Anat.  et  Physiol.  du  Systeme  Nerveux,"  torn.  ii.  p.  289. 


510  OF   RESPIRATION. 

stimulus ;  but  that  it  may  in  some  degree  be  restored  by  rest,  even  when  the 
lung  is  removed  from  the  body.  When  the  stimulation  is  long  continued,  how- 
ever, as  by  intense  irritation  of  the  mucous  membrane  during  life,  the  contractile 
tissue  passes  into  a  state  which  resembles  the  tonic  contraction  of  muscular  fibre. 
The  contractility  is  greatly  affected  by  the  mode  of  death,  and  is  remarkably 
diminished  by  the  action  of  vegetable  narcotics,  particularly  stramonium  and 
belladonna :  whilst  it  seems  to  be  scarcely  at  all  affected  by  hydrocyanic  acid. 
These  facts  are  very  important,  as  throwing  light  upon  certain  diseased  condi- 
tions. It  has  long  been  suspected,  that  the  dyspnoaa  of  Spasmodic  Asthma 
depends  upon  a  constricted  state  of  the  smaller  bronchial  tubes,  excited  through 
the  nervous  system,  frequently  by  a  stimulating  cause  at  some  distance ;  and ' 
there  din  be  now  little  doubt  that  such  is  the  case.  The  peculiar  influence  of 
stramonium  and  belladonna,  in  diminishing  the  contractility  of  these  fibres,  har- 
monizes remarkably  with  the  well-known  fact  of  the  relief  frequently  afforded 
by  them  in  this  distressing  malady.  It  has  been  maintained  by  Dr.  Radcliffe 
Hall/  that  the  contractility  of  the  bronchial  tubes  is  called  into  action  in  each 
expiratory  movement,  to  assist  in  emptying  the  lungs.  But  no  evidence  has 
been  adduced  in  support  of  this  doctrine ;  and  its  improbability  is  apparent  from 
the  obvious  fact,  that  a  contraction  of  the  air-tubes  would  impede,  rather  than 
promote,  the  emptying  of  the  air- vesicles.  It  seems  more  probable  that  it  serves 
to  regulate  the  supply  of  air  to  the  lobules,  in  accordance  with  the  wants  of  the 
system,  just  as  the  contractility  of  the  minute  arteries  regulates  the  supply  of 
blood  to  the  organs  to  which  they  proceed ;  and  it  may  possibly  be  through  this 
channel,  that  the  remarkable  variation  is  effected  in  the  amount  of  respiration, 
which  adapts  the  quantity  of  heat  produced  to  the  depression  of  the  external 
temperature  (§  538).  It  has  been  further  suggested  by  Dr.  W.  T.  Gairdner,2 
that  the  contractility  of  the  smaller  bronchi  may  serve  to  expel  collections  of 
mucus  which  have  accumulated  in  them,  and  which  neither  ciliary  action  nor 
the  ordinary  expiratory  efforts  suffice  to  displace. 

543.  Although  there  is  no  sufficient  reason  to  believe  that  the  Lungs  are 
possessed  of  any  power  of  vital  contractility,  yet  their  Elasticity  prevents  them 
from  being  altogether  passive  agents  in  the  respiratory  operation.  The  elastic 
tension  is  rapidly  increased  by  the  dilatation  of  the  lungs  with  air ;  and  the  care- 
fully -conducted  experiments  of  Dr.  Hutchinson3  lead  him  to  estimate  it  at  cer- 
tainly not  less  than  £  Ib.  upon  each  square  inch  of  surface,  when  the  lungs  have 
been  filled  by  the  deepest  possible  inspiration;  so  that  its  whole  amount  (reck- 
oning an  average  surface  of  300  sq.  in.  for  the  male,  and  247  sq.  in.  for  the 
female),  will  be  not  less  than  150  Ibs.  for  the  male,  and  123  £  Ibs.  for  the  female. 
This  force  is  exerted  in  aid  of  the  expiratory  movement,  and  is  directly  anta- 
gonistic to  the  i'nspiratory ;  so  that  the  inspiratory  muscles  must  overcome  it,  in 
order  to  produce  complete  distension  of  the  pulmonary  cavities.  This  disten- 
sion is  entirely  accomplished  by  the  action  of  the  muscles  external  to  the  thorax, 
or  partly  forming  its  parietes.  The  lung  completely  fills  the  cavity  of  the  pleura, 
in  the  healthful  state  at  least;  so  that,  when  this  is  enlarged,  a  vacuum  would 
be  produced,  if  it  were  not  occupied  by  a  corresponding  enlargement  of  the  lung ; 
and  to  effect  this,  the  air  rushes  down  the  trachea,  and  thence  passes  into  the 
entire  substance  of  the  lung,  which  it  fills  out  in  every  dimension.  This 
distension  is  much  more  complete  than  any  that  could  be  occasioned  by 
simple  insufflation  from  the  trachea;  for,  long  before  the  internal  pressure 
could  overcome  the  resistance  set  up  by  the  elasticity  of  the  lungs,  and 
still  more  by  that  of  the  parietes  of  the  chest  (§  545),  to  the  full  dilatation 

1  "Transactions  of  the  Provincial  Med.  Association,"  1850. 

2  "Edinburgh  Monthly  Journal,"  May,  1851. 

3  "Cyclopaedia  of  Anatomy,"  art.  "Thorax,"  vol.  iv.  p.  1058. 


OF   THE  RESPIRATORY   MOVEMENTS.  511 

of  the  air-vesicles,  the  tissue  of  the  lung  itself  would  be  almost  certain  to 
give  way.  This  has  actually  happened  in  numerous  instances;  and  it  consti- 
tutes a  very  forcible  objection  to  the  use  of  any  apparatus  for  artificial  respira- 
tion, whose  action  is  that  of  "  insufflation."  The  complete  dependence  of  the 
expansion  of  the  Lungs  upon  the  enlargement  of  the  cavity  of  the  chest  is  well 
shown  by  the  effect  of  admission  of  air  into  the  pleural  cavity.  When  an  aper- 
ture is  made  on  either  side,  so  that  the  air  rushes  in  at  each  inspiratory  move- 
ment, the  expansion  of  the  lung  on  that  side  is  diminished,  or  entirely  prevented, 
in  proportion  to  the  size  of  the  aperture.  If  air  can  enter  through  it  more  rea- 
dily than  through  the  trachea,  an  entire  collapse  of  the  lung  takes  place;  and 
by  making  such  an  aperture  on  each  side,  complete  asphyxia  is  produced.  But 
if  it  be  too  small  to  admit  the  very  ready  passage  of  air,  the  vacuum  produced 
by  the  inspiratory  movement  is  more  easily  filled  by  the  distension  of  the  lungs, 
than  by  the  rush  of  air  into  the  pleural  cavity;  so  that  a  sufficient  amount  of 
change  takes  place  for  the  maintenance  of  life.  This  is  frequently  observed  in 
the  case  of  penetrating  wounds  of  the  thorax,  in  the  surgical  treatment  of  which, 
it  is  of  great  importance  to  close  the  aperture  as  completely  as  possible;  when 
this  has  been  accomplished,  the  air  that  had  found  its  way  into  the  cavity  is 
soon  absorbed,  and  the  lung  resumes  its  full  play.  Where  one  lung  is  ob- 
structed by  tubercular  deposit,  or  is  prevented  in  any  other  way  from  rightly 
discharging  its  function,  an  opening  that  freely  admits  air  into  the  pleural  cavity 
of  the  other  side,  is  necessarily  attended  with  an  immediately  fatal  result ;  and 
in  this  manner  it  not  unfrequently  happens  that  chronic  pulmonary  diseases 
suddenly  terminate  in  Asphyxia,  a  communication  being  opened  by  ulceration 
between  a  bronchial  tube  and  the  cavity  of  the  thorax. 

544.  Of  the  Respiratory  Movements. — The  dilatation  of  the  Pleural  cavity 
during  Inspiration  is  chiefly  accomplished  by  the  contraction  of  the  Diaphragm, 
which,  from  the  high  arch  that  it  previously  formed,  becomes  nearly  plane ;  in 
this  change  of  figure,  it  presses  on  the  abdominal  viscera,  so  as  to  cause  them  to 
protrude,  which  they  are  enabled  to  do  by  the  relaxation  of  the  abdominal  mus- 
cles. In  ordinary  tranquil  breathing  (especially  in  children),  the  action  of  the 
diaphragm  is  alone  nearly  sufficient  to  produce  the  necessary  exchange  of  air ; 
but,  when  a  full  inspiration  is  required,  the  cavity  of  the  chest  is  dilated  late- 
rally and  antero-posteriorly,  as  well  as  inferiorly.  The  enlargement  of  the  chest 
in  both  these  directions  is  effected  by  the  elevation  of  the  ribs ;  for  whilst,  in 
the  undilated  state  of  the  thorax,  the  ribs  form  an  angle  with  their  cartilages, 
which  becomes  less  and  less  obtuse  as  we  pass  from  the  first  rib  downwards,  the 
elevation  of  the  ribs  tends  to  bring  them  and  their  cartilages  more  nearly  into 
a  line,  and  thus  separates  them  more  widely  from  the  median  plane,  and  at  the 
same  time  causes  them  to  push  forwards  the  sternum.  Owing  to  the  greater 
length  of  the  lower  true  ribs,  and  the  greater  obliquity  of  their  junction  with 
their  cartilages,  both  these  changes  are  more  considerable  in  the  lower  part  of 
the  thorax  than  in  the  upper ;  and  this  is  especially  the  case  in  adult  men,  whose 
respiration  has  been  designated  as  "  inferior  costal,"  whilst  in  females  the  mo- 
bility of  the  first  rib  and  of  the  whole  of  the  upper  part  of  the  thorax  is  greater, 
so  that  their  respiration  may  be  designated  as  "  superior  costal."  The  thoracic 
muscles  whose  contraction  participates  in  the  ordinary  movements  of  Inspiration 
are  (according  to  Dr.  Hutchinson,  Op.  cit.,  p.  1055)  the  external  intercostal, 
with  those  portions  of  the  internal  intercostals  which  pass  between  the  cartilages, 
the  levatores  costarum,  and  a  portion  of  the  triangularis  sterni,  all  of  which 
have  the  same  action,  that  of  elevating  the  ribs.  On  the  other  hand,  the  tho- 
racic Expiratory  muscles  are  the  proper  costal  portion  of  the  znfcrwa^  intercostals, 
with  the  infracostales,  and  a  part  of  the  triangularis  sterni.  The  expiratory 
movement  will  be  assisted  also  by  the  abdominal  muscles,  which  antagonize  the 
diaphragm  by  pressing  back  the  abdominal  viscera,  and  thus  causing  its  ascent 


512 


OF    RESPIRATION. 


so  soon  as  it  has  become  relaxed.  There  are  many  accessory  muscles,  however, 
which  take  a  share  in  violent  respiratory  movements,  both  inspiratory  and  ex- 
piratory. Thus  all  the  muscles  which  elevate  the  scapula  may  act  through  it 
upon  the  ribs,  and  the  scaleni  act  directly  upon  the  first  rib ;  whilst  all  those 
which  erect  the  spine,  fix  more  perfectly  the  origins  of  these  and  other  muscles 
which  are  to  act  upon  the  thorax.  So,  again,  the  expiratory  movement  is  aided 
by  the  longissimus  dorsi,  sacro-lumbalis,  and  other  muscles  which  tend  to  de- 
press the  ribs.  In  difficult  respiration,  almost  every  muscle  in  the  body  is  made 
in  some  way  subservient  to  the  distension  of  the  chest;  thus,  a  patient  suffering 
under  urgent  dyspnoea  instinctively  lays  hold  of  some  fixed  object,  so  as  to  pre- 
vent his  upper  extremities  from  moving;  and  thus  his  scapula  becomes  a  fixed 
point,  from  which  the  pectorales  (major  and  minor)  and  serratus  magnus  can 
aid  in  elevating  the  ribs. 

545.  The  relative  amount  of  muscular  force  which  is  required  for  these  two 
movements  respectively,  is  affected  in  a  very  remarkable  manner  by  the  elasti- 
city of  the  walls  of  the  thoracic  cavity;  for  this  (like  the  elasticity  of  the  lungs), 
supplies  a  force  which  greatly  aids  the  expiratory  movement,  whilst  it  offers  a 
corresponding  opposition  to  the  mspiratory.  Here,  also,  the  degree  of  force 
exerted  increases  very  rapidly  with  the  degree  of  distension.  Thus  in  a  body 
experimented  on  by  Dr.  Hutchinson  (Op.  cit.  p.  1056),  the  following  were  the 
relations  between  the  amount  of  air  forced  in,  the  resisting  elasticity,  as  shown 
by  the  height  of  mercury  supported,  the  actual  pressure  upon  each  square  inch 
of  surface  which  this  indicated,  and  the  total  pressure  over  the  surface  of  the 
chest,  reckoning  its  area  at  206  square  inches  : — 


Air  forced  in 


To  this  451.9  Ibs.  must  be  added  at  least  128  Ibs.  for  the  elastic  force  of  the 
lungs  themselves  at  that  degree  of  distension,  making  altogether  580  Ibs. ;  and 
as  the  subject  of  this  observation  could  expire  during  life  considerably  more  air 
than  the  highest  amount  forced  into  his  chest  after  death,  there  can  be  little 
doubt  (judging  from  the  rapid  ratio  in  which  the  elastic  force  increases  when 
the  distension  is  approaching  its  limits)  that  the  muscular  power  required  to 
overcome  this,  towards  the  close  of  a  very  deep  inspiration,  could  not  have  been 
less  than  1000  Ibs.  The  co-operation  of  the  ilastic  resistance  with  the  expira- 
tory movement,  and  its  antagonism  to  the  inspiratory,  is  doubtless  the  principal 
cause  why  the  power  of  the  expiratory  muscles,  as  tested  by  the  height  of  the 
column  of  mercury  supported  by  the  air,  should  always  be  greater  than  that  of 
the  inspiratory  muscles  (see  Dr.  Hutchinson,  Op.  cit.  p.  1061) ;  and  why  the 
expiratory  power  should  be  very  much  greater  when  the  chest  has  been  well 
filled  with  air,  than  when  it  is  comparatively  empty.  The  following  is  given  by 
Dr.  Hutchinson  as  the  range  through  which  these  powers  may  vary  within  the 
limits  of  health  : — 


Pressure  in  height 

Pressure 

Total 

Cubic  inches. 

of  Mercury.          per  sq 

.  in. 

Pressure. 

.        70 

Resisting  elasticity 

1 

.00 

inch. 

7 

.8 

oz. 

104.4 

Ibs. 

90 

it 

ti 

1 

.50 

it 

11 

.7 

" 

150.6 

« 

180 

« 

it 

3 

.25 

it 

25 

.8 

n 

326.3 

a 

200 

" 

it 

4 

.50 

(C 

35 

.1 

H 

451.9 

M 

Power 
Innpiratory 

1.6  in 
2.0 
2.5 
3.5 
4.5 
5.6 
6.0 
7.0 

if 

VtU6( 

ch. 

Power  ol 
sles.                                                                                       Expiratory  M 

Weak     2.0  in 

uscles. 
ches. 

Ordinary 
Strong   .... 
Very  strong   . 
Remarkable   .         .         . 
Very  remarkable    . 

2.5 
3.5 
4.5 

5.8 
7.0 
8.5 

Very  extraordinary         .         .         .         »         .10.0 

OF   THE   RESPIRATORY   MOVEMENTS.  513 

The  expiratory  power  may  be  augmented  by  the  habitual  performance  of  move- 
ments in  which  they  participate ;  and  thus  the  inspiratory  power  is  the  prefer- 
able test  of  the  vis  vitse.  This  has  been  found  by  Dr.  Hutchinson  to  bear  some 
relation  to  height,  being  greatest  (on  an  average  of  a  considerable  number  of 
cases)  when  the  stature  is  5  feet  7  or  8  inches ;  and  diminishing  above  that 
height,  as  well  as  below  it. 

546.  It  is  impossible  to  form  a  correct  estimate,  by  observations  on  one's  self, 
of  the  usual  number  and  degree  of  the  respiratory  movements,  since  the  direc- 
tion of  the  attention  to  them  is  certain  to  increase  their  frequency  and  amount. 
In  general  it  may  be  stated,  that  from  16  to  20  alternations  usually  occur  in  a 
minute  ;*  of  these,  the  ordinary  inspirations  involve  but  little  movement  of  the 
thorax ;  but  a  greater  exertion  is  made  at  about  every  fifth  recurrence.     The 
average  numerical  proportion  of  the  respiratory  movements  to  the  pulsations  of 
the  heart  is  about  1  :  5,  1  :  4$,  or  1  :  4  ;  and  when  this  proportion  is  widely 
departed  from,  there  is  reason  to  suspect  some  obstruction  to  the  aeration  of  the 
blood,  or  some  disorder  of  the  nervous  system.     Thus  in  Pneumonia,  in  which 
a  greater  or  less  amount  of  the  lung  is  unfit  for  its  office,  the  number  of  respi- 
rations increases  in  a  more  rapid  proportion  than  the  acceleration  of  the  pulse ; 
so  that  the  ratio  becomes  as  1  to  3,  or  even  1  to  2,  in  accordance  with  the  de- 
gree of  engorgement.2     In  Hysterical  patients,  however,  a  similar  increase,  or 
even  a  greater  one,  may  take  place  without  any  serious  cause ;  thus  Dr.  Elliot- 
son3  mentions  a  case,  in  which  the  respiratory  movements  of  a  young  female, 
through  nervous  affection,  were  98  or  even  106,  whilst  the  pulse  was  104.     On 
the  other  hand,  the  respirations  in  certain  typhoid  conditions  and  in  narcotic 
poisoning  become  abnormally  slow,  owing  to  the  torpid  condition  of  the  nervous 
centres,  the  proportion  being  1  to  6,  or  even  1  to  8 ;   and  in  such  cases,  the 
lungs  not  unfrequently  become  cedematous,  from  a  cause  hereafter  to  be  men- 
tioned (§  556). 

547.  Not  only  the  rate  of  the  Respiratory  movements,  but  also  their  extent, 
is  affected  by  various  morbid  conditions;   thus  when  dislocation  of  the  spine 
takes  place  above  the  origin  of  the  intercostal  nerves,  but  below  that  of  the 
phrenic,  so  that  the  former  are  paralyzed,  the  respiratory  movement  is  confined 
to  the  diaphragm :  and  as  this  is  insufficient,  serum  is  effused  into  the  lungs, 
and  a  slow  Asphyxia  supervenes,  which  usually  proves  fatal  in  from  three  to 
seven  days.     Even  where  the  muscles  and  nerves  are  all  capable  of  action,  the 
full  performance  of  the  inspiratory  movements  is  prevented,  by  the  solidification  or 
engorgement  of  any  part  of  the  lung,  which  interferes  with  its  free. distension ; 
or  by  adhesions  between  the  pleural  surfaces,  which  offer  a  still  more  direct  im- 
pediment.    When  these  adhesions  are  of  long  standing,  they  are  commonly 
stretched  into  bands,  by  the  continual  tension  to  which  they  are  subjected.     If 
the  impeding  cause  affect  both  sides,  the  movements  of  both  will  be  alike  inter- 
fered with ;  but  if  one  side  only  be  affected,  its  movements  will  be  diminished, 
whilst  those  of  the  other  remain  natural ;  and  the  physician  hence  frequently 
derives  an  indication  of  great  value,  in  regard  to  the  degree  in  which  the  lung 
is  incapable  of  performing  its  functions.     It  is  to  be  remembered,  however,  that 
the  action  both  of  the  diaphragm  and  of  the  elevators  of  the  ribs  may  be  pre- 
vented, by  pain  either  in  the  muscles  themselves  or  in  the  parts  which  they 
move ;  thus  the  descent  of  the  diaphragm  is  checked  by  inflammation  of  the 
abdominal  viscera  or  of  the  peritoneum ;  and  that  of  the  intercostals  by  rheu- 

1  See  Dr.  Hutchinson's  Table,  in  "Cyclop,  of  Anat.  and  Phys.,"  vol.  iv.  p.  1085. 

2  See  a  Paper  by  Dr.  Hooker,  on  the  "Relation  between  the  Respiratory  and  Circulat- 
ing Functions,"  in  the  "Boston  (N.  E.)  Medical  and  Surgical  Journal;"  an  abstract  of 
which  will  be  found  in  the  "  British  and  Foreign  Medical  Review,"  vol.  iv.  p.  263. 

3  "Physiology,"  p.  215,  note. 

33 


514  OF   RESPIRATION. 

matism,  pleuritis,  pericarditis,  or  other  painful  disorders  of  the  parts  forming 
the  parietes  of  the  thorax. 

548.  We  have  now  to  inquire  into  the  mode  in  which  the  Muscular  move- 
ments of  Respiration  are  kept  up  by  nervous  power. — There  can  be  no  doubt 
that  these  movements,  though  partly  under  the  control  of  the  Will,  are  essentially 
"  automatic"  in  their  nature.     Their  chief  centre  is  the  upper  part  of  the 
Medulla  Oblongata^  into  which  may  be  traced  the  principal  excitor  nerves  that 
convey  the  stimulus  on  which  the  movements  are  dependent,  whilst  from  it 
proceed  the  principal  motor  nerves  by  which  they  are  carried  into  effect.     And 
thus  it  happens  that  the  whole  of  the  Encephalon  may  be  removed  from  above, 
and  the  Spinal  cord  (as  far  up  as  the  origin  of  the  phrenic  nerve)  from  below, 
without  suspending  the  most  essential  of  the  respiratory  movements.     But  other 
parts  of  the  automatic  centres  are  concerned  in  the  ordinary  movements  of  re- 
spiration ;  and  there  is  probably  no  part  that  may  not  be  excited  to  action,  by 
the  extraordinary  stimulus  which  results  from  a  prolonged  interruption  to  the 
aeration  of  the  blood  (§  546).     The  chief  "  excitor"  of  the  respiratory  move- 
ments is  unquestionably  the  Pneumogastric  nerve.     When  this  is  divided  on 
both  sides,  according  to.  the  experiments  of  Dr.  J.  Reid,1  the  number  of  respi- 
ratory movements  is  considerably  diminished,  usually  about  one-half.     Now  if 
this  nerve  excites  the  motions  of  respiration  by  its  powerful  action  in  producing 
sensation,  we  should  expect  to  find  its  trunk  endowed  with  considerable  sensi- 
bility, which  is  not  the  case ;  for  all  experimenters  agree  in  stating  that,  when 
its  trunk  is  pinched  or  pricked,  the  animal  does  not  exhibit  signs  of  pain  nearly 
so  acute,  as  when  the  trunks  of  the  ordinary  spinal  nerves,  or  of  the  fifth  pair, 
are  subjected  to  similar  treatment.     It  cannot  be  questioned,  however,  that  its 
power  as  an  excitor  of  respiration  is  very  great ;  since,  besides  the  fact  of  the 
diminution  in  the  number  of  inspirations  which  occurs  immediately  on  section 
of  it,  irritation  of  its  trunk  in  the  neck  is  instantly  followed  by  an  act  of  in- 
spiration.    It  is  evident  that  this  power  must  arise  from  impressions  made  upon 
its  peripheral  extremities.     The  impression  is  probably  due  to  the  presence  of 
venous  blood  in  the  capillaries  of  the  lungs ;  or,  as  Dr.  M.  Hall  thinks,  to  the 
presence  of  carbonic  acid  in  the  air-cells.     Either  or  both  may  be  true. — The 
Pneumogastric  nerve,  however,  is  not  the  only  excitor  of  the  respiratory  move- 
ments 'j  since,  when  the  nerve  is  cut  on  each  side,  they  still  continue,  though 
with  less  frequency.     The  removal  of  the  Encephalon  diminishes  the  frequency 
of  the  respiratory  movements,  whether  it  be  performed  before  or  after  the  section 
of  the  Vagi.     Dr.  Reid  found  that  in  a  kitten  of  a  day  old,  in  which  the 
inspirations  had  been  100  per  minute,  they  fell  to  40  when  the  Encephalon  was 
removed;  and  on  subsequently  cutting  the  Pneumogastrics,  the  number   of 
inspirations  instantly  fell  to  between  3  and  4  in  the  minute,  and  continued  so 
for  some  time.     Hence  it  has  been  supposed  that  the  respiratory  movements  are 
partly  dependent  upon  sensation,  a  motor  influence  being  excited  by  it ;  but 
it  may  be  fairly  surmised,  from  the  close  dependence  of  nervous  activity  upon 
the  oxygenation  of  the  blood,  that  a  "  besoin  de  respirer"  may  originate  in  the 
circulation  of  imperfectly  aerated  blood  in  the  nervous  centres  themselves,  and 
may  become  the  direct  excitor  of  respiratory  movements. 

549.  But  why   (it  may  be  asked)  do  the  movements  continue,  when  the 
Pneumogastrics  have  been  divided,  and  the  Encephalon  has  been  removed  ?     It 
is  evident  that  there  must  be  other  exciters  to  the  action  of  the  respiratory 
muscles.     Amongst  these,  the  nerves  distributed  to  the  general  surface,  and 

1  "Edinb.  Med.  and  Surg.  Journ.,"  vol.  li. ;  and  "Phys.,  Anat.,  and  Pathol.  Res.," 
p.  177. — Dr.  Reid  has  satisfactorily  shown  the  statement  of  many  experimenters,  that  the 
inspirations  are  increased  in  frequency  after  this  operation,  to  be  erroneous ;  this  idea  hav- 
ing originated  in  their  very  prolonged  and  laborious  character. 


OP   THE   RESPIRATORY   MOVEMENTS.  515 

particularly  to  the  face,  probably  perform  an  important  part ;  and  in  exciting 
the  first  inspiration,  the  Fifth  pair  seems  the  principal  agent.  It  has  long  been 
a  well-known  fact,  that  the  first  inspiratory  effort  of  the  new-born  infant  is  most 
vigorously  performed,  when  the  cool  external  air  comes  into  contact  with  the  face; 
and  that  impressions  on  the  general  surface,  such  as  a  slap  of  the  hand  on  the 
nates,  are  often  effectual  in  exciting  the  first  inspiratory  movements,  when  they 
would  not  otherwise  commence.  Dr.  M.  Hall  relates  an  interesting  case,  in 
which  the  first  inspiration  was  delayed,  simply  because  the  face  was  protected  by 
the  bed-clothes  from  the  atmosphere  j1  and,  on  lifting  up  these,  the  infant  imme- 
diately breathed.  Dr.  M.  Hall  has  also  mentioned  the  important  fact,  that 
although,  if  the  cerebrum  be  removed,  and  the  pneumogastrics  divided,  in  a 
young  kitten,  the  number  of  acts  of  respiration  will  be  reduced  to  four  in  a 
minute,  yet  by  directing  a  stream  of  air  on  the  animal,  or  by  irritating  various 
parts  of  the  general  surface,  we  may  excite  twenty  or  thirty  acts  of  respiration 
within  the  same  space  of  time.  He  further  remarks,  that  in  the  very  young 
warm-blooded  animal,  as  in  the  cold-blooded  animal,  the  phenomena  of  the 
excito-motor  power  are  far  more  vividly  manifested  than  in  the  older  and  warm- 
blooded. In  the  very  young  kitten,  even  when  asphyxiated  to  insensibility, 
every  touch,  contact,  or  slight  blow,  every  jar  of  the  table,  any  sudden  impres- 
sion of  the  external  air,  or  that  of  a  few  drops  of  cold  water,  induces  at  once 
energetic  reflex  movements,  and  acts  of  inspiration.  This  may  be  looked  upon 
as  Nature's  provision  for  the  first  establishment  of  the  acts  of  inspiration  in  the 
new-born  animal. — But  the  influence  of  the  nerves  of  the  general  system  is  by 
no  means  wanting  in  the  adult ;  as  many  familiar  facts  demonstrate.  Every  one 
knows  the  fact,  that  the  first  plunge  into  cold  water,  the  first  descent  of  the  streams 
of  the  shower-bath,  or  even  the  dashing  of  a  glass  of  cold  water  in  the  face,  will 
produce  inspiratory  efforts;  and  this  fact  has  many  important  practical  appli- 
cations. Thus  in  the  treatment  of  Asphyxia,  whether  congenital,  or  the  result 
of  narcotic  poisoning,  drowning,  &c.,  the  alternate  application  of  cold  and  heat 
is  found  to  be  one  of  the  most  efficacious  means  of  restoring  the  respiratory 
movements ;  and  a  paroxysm  of  hysteric  laughter  may  be  cut  short  by  dashing 
a  glass  of  cold  water  in  the  face.  One  of  Dr.  Reid's  experiments  strikingly 
demonstrates  the  variety  of  the  provisions  that  have  been  made  for  the  perform- 
ance of  this  function.  After  dividing  the  pneumogastrics,  and  removing  the 
cerebrum  and  cerebellum,  he  divided  the  spinal  cord  high  up  in  the  neck,  so  as 
to  cut  off  the  communication  between  the  spinal  nerves  and  the  Medulla  Oblon- 
gata;  and  he  found  that  the  frequency  of  the  respiratory  movements  was  still 
further  diminished,  although  they  were  not  even  then  entirely  suspended ;  their 
continuance,  after  every  channel  of  excitation  appeared  to  have  been  cut  off 
being  probably  dependent  (as  Dr.  Reid  has  suggested)  on  the  circulation  of  im- 
perfectly aerated  blood  in  the  Medulla  Oblongata. — It  seems  not  improbable 
that  even  the  Sympathetic  nerve,  which  derives  many  filaments  from  the  Cere- 
bro-Spinal  system,  and  which  especially  communicates  with  the  Pneumogastric 
nerves,  may  be  one  of  the  excitors  to  this  function ;  and  this,  perhaps,  not  only 
through  its  ramifications  in  the  lungs,  which  are  considerable,  but  also  by  its 
distribution  on  the  systemic  vessels ;  so  that  it  may  convey  to  the  Spinal  Cord 
the  impression  of  imperfectly-arterialized  blood  circulating  through  these,  such 
as  the  Pneumogastric  is  believed  to  transmit  from  the  lungs. 

550.  The  Motor  or  "  efferent"  nerves  concerned  in  the  function  of  Respira- 
tion, are  those  which  Sir  C.  Bell  has  grouped  together  in  his  "  respiratory  sys- 
tem." The  most  important  of  these,  the  Phrenic,  arises  from  the  upper  part 
of  the  Spinal  Cord ;  the  Intercostals  much  lower  down ;  whilst  the  Facial  nerve 
and  the  Spinal  Accessory,  to  the  latter  of  which,  as  will  be  shown  hereafter 

1  "  New  Memoir  on  the  True  Spinal  Marrow,"  &c.,  p.  29. 


516  OF   RESPIRATION. 

(CHAP.  xiv.  Sect.  2),  the  motor  powers  of  the  Pneumogastric  are  chiefly  due, 
take  their  origin  in  the  Medulla  Oblongata  itself.  But  we  must  not  decide  upon 
the  connection  of  a  particular  nerve  with  a  particular  segment  of  the  Spinal 
Cord,  simply  because  it  diverges  from  it  at  that  point;  and  the  analogy  of  the 
Invertebrated  classes  favors  the  idea  that  a  direct  structural  connection  exists 
between  the  ganglionic  centre  of  the  Respiratory  movements,  and  the  nerves 
which  transmit  their  influence  to  the  muscles.  Upon  this  point,  however,  it  is 
unsafe  to  speculate ;  and  we  can  only  state  it  as  a  possibility,  that  some  such 
connection  may  be  established  in  Vertebrated  animals  through  the  white  columns 
of  the  spinal  cord. 

551.  That  the  Respiratory  movements,  as  ordinarily  performed,  are  essen- 
tially independent  of  the  Will,  appears  not  only  from  our  own  consciousness, 
but  also  from  cases  of  paralysis;  in  some  of  which,  the  power  of  the  will  over 
the  muscles  has  been  lost,  whilst  the  movements  have  been  kept  up  by  the  reflex 
action  of  the  Medulla  Oblongata  or  respiratory  ganglion;  whilst  in  others,  some 
of  the  respiratory  muscles  have  been  motionless  during  ordinary  breathing,  and 
yet  have  remained  under  the  power  of  the  will.1  That  consciousness  is  not  a 
necessary  link  in  the  chain  of  causes  which  produce  the  respiratory  movements, 
we  are  enabled  to  judge  from  the  phenomena  presented  by  the  human  being  in 
sleep  and  .  coma,  by  anencephalous  foetuses,  and  by  decapitated  animals.  This 
conclusion  is  confirmed  by  a  case  recorded  by  Dr.  H.  Ley,3  who  had  under  his 
care  a  patient  in  whom  the  pneumogastrics  appeared  to  be  diseased;  the  lungs 
suffered  in  the  usual  way  in  consequence,  and  the  patient  had  evidently  labori- 
ous breathing ;  but  he  distinctly  said  that  he  felt  no  uneasiness  in  his  chest. — 
The  experience  of  every  one  informs  him  that  the  Respiratory  movements  are 
partly  under  the  control  and  direction  of  the  will,  though  frequently  unre- 
strainable  by  it.  In  ordinary  circumstances,  when  the  blood  is  being  perfectly 
aerated,  and  there  is  a  sufficient  amount  of  arterial  blood  in  the  system  to  carry 
on  the  functions  of  life  for  a  short  time,  we  can  suspend  the  respiratory  actions 
during  a  few  seconds  without  any  inconvenience.  If,  however,  we  endeavor  to 
prolong  the  suspension,  the  stimulus  conveyed  by  the  excitor  nerves  to  the  Me- 
dulla Oblongata  becomes  too  strong,  and  we  cannot  avoid  making  inspiratory 
efforts ;  and  if  the  suspension  be  still  further  prolonged,  the  whole  body  becomes 
agitated  by  movements  which  are  almost  of  a  convulsive  nature,  and  no  effort 
of  the  will  can  then  prevent  the  ingress  of  air.3  It  is  easy  to  understand  why, 
in  the  higher  animals  at  least,  and  more  especially  in  Man,  the  respiratory  ac- 
tions should  be  thus  placed  under  the  control  of  the  will:  since  they  are  sub- 
servient to  the  production  of  those  sounds,  by  which  individuals  communicate 
their  feelings  and  desires  to  each  other ;  and  which,  when  articulate,  are  capa- 
ble of  so  completely  expressing  what  is  passing  in  the  mind  of  the  speaker.  If 
the  respiratory  muscles  of  Man  were  no  more  under  his  control  than  they  ap- 
pear to  be  in  the  Insect  or  Molluscous  animal,  he  might  be  provided  with  the 
most  perfect  apparatus  of  speech,  and  yet  he  would  not  be  able  to  employ  it  to 
any  advantage. 

1  Such  cases  are  mentioned  by  Sir  C.  Bell,  in  the  Appendix  to  his  work  on  the  Nervous 
System. 

2  "On  Laryngismus  Stridulus,"  p.  417. 

3  It  is  asserted  by  M.  Bourdon  ("  Recherches  sur  le  Mecanisme  de  la  Respiration,"  p. 
21),  that  no  person  ever  committed  suicide,  though  many  have  attempted  to  do  so,  by 
simply  holding  the  breath ;  the  control  of  the  will  over  the  respiratory  muscles  not  being 
sufliciently  great,  to  antagonize  the  stimulus  of  the  "besoin  de  respirer,"  when  this  has 
become  aggravated  by  the  temporary  cessation  of  the  action.     But  such  persons  have  suc- 
ceeded better,  by  holding  the  face  beneath  the  surface  of  water ;  because  here  another  set 
of  muscles  is  called  into  action,  which  are  much  more  under  the  control  of  the  will  than 
are  those  of  respiration;   and  a  strong  volition  applied  to  these  can  prevent  all  access  of 
air  to  the  lungs,  however  violent  may  be  the  inspiratory  efforts. 


OF   THE   RESPIRATORY   MOVEMENTS.  517 

552.  The  motor  power  of  the  Respiratory  nerves  is  exercised,  however,  not 
only  on  the  muscles  which  perform  the  inspiratory  and  expiratory  movements, 
but  on  those  which  guard  the  entrance  to  the  windpipe,  and  also  on  certain 
other  parts.     The  movements  of  the  internal  respiratory  apparatus  are  chiefly, 
if  not  entirely,  effected  through  the  medium  of  the  motor  fibres,  which  the 
Pneumogastric  contains.     These  motor  fibres  exist  in  very  different  proportions 
in  its  different  branches.     For  example,  the  pharyngeal  and  oesophageal  branches, 
by  which  the  muscles  of  deglutition  are  excited  to  contraction  (§§  427,  428), 
possess  a  much  larger  amount  of  them,  and  exhibit  much  less  sensibility  when 
irritated,  than  do  other  divisions  of  the  trunk.     Between  tne  superior  and  in- 
ferior laryngeal  nerves,  again,  there  is  an  important  difference,  which  anatomical 
and  experimental  research   has  now  very  clearly  demonstrated.     It  has  long 
been  known,  that  section  of  the  Pneumogastrics  in  the  neck,  above  the  inferior 
laryngeals,  is  frequently  followed  by  suffocation,  resulting  from  closure  of  the 
glottis ;  and  hence  it  has  been  inferred,  that  the  office  of  the  inferior  laryngeals 
was  to  call  into  action  the  dilators  of  the  larynx,  whilst  the  superior  laryngeals 
were  supposed  to  stimulate  the  constrictors.     This  view,  however,  is  incorrect. 
It  is  inconsistent  with  the  results  of  anatomical  examination  into  the  respective 
distribution  of  these  two  trunks ;  and  it  has  been  completely  overthrown  by  the 
very  careful  and  satisfactory  observations  and  experiments  of  Dr.  J.  Reid,1 
which  have  established  that,  whilst  the  inferior  laryngeal  is  the  motor  nerve  of 
nearly  all  the  larycigeal  muscles,  the  superior  laryngeal  is  the  excitor  or  afferent 
nerve,  conveying  to  the  Medulla  Oblongata  the  impressions  by  which  muscular 
movements  are  excited.     Its  motor  endowments  are  limited  to  the  crico-thyroid 
muscle,  to  which  alone  of  all  the  muscles  its  filaments  can  be  traced,  the  re- 
mainder being  distributed  beneath  the  mucous  surface  of  the  larynx ;  and  its 
sensibility  is  very  evident,  when  it  is  pinched  or  irritated  during  experiments 
upon  it.     On  the  other  hand,  the  motor  character  of  the  inferior  laryngeal 
branch  is  shown  by  its  very  slight  sensibility  to  injury,  its  nearly  exclusive  dis- 
tribution to  muscles,  and  its  influence  in  exciting  contraction  of  these  when  its 
separated  trunk  is  stimulated. 

553.  It  has  been  ascertained  by  Dr.  J.  Reid,  that,  if  the  inferior  laryngeal 
branches  be  divided,  or  the  trunk  of  the  pneumogastric  be  cut  above  their  origin 
from  it,  there  is  no  constriction  of  the  glottis,  but  a  paralyzed  state  of  its  mus- 
cles.    After  the  first  paroxysm  occasioned  by  the  operation,  a  period  of  quies- 
cence   and  freedom   from    dyspnosa  often   supervenes,  the  respirations   being 
performed  with  ease  so  long  as  the  animal  remains  at  rest ;   but  an  unusual 
respiratory  movement,  such  as  takes  place  at  the  commencement  of  a  struggle, 
induces  immediate  symptoms  of  suffocation — the  current  of  air  carrying  inwards 
the  arytenoid  cartilages,  which  are  rendered  passive  by  the  paralyzed  state  of 
their  muscles  j  and  these,  falling  upon  the  opening  of  the  glottis,  like  valves, 
obstruct  the  entrance  of  air  into  the  lungs.     The  more  effort  is  made,  the  greater 
will  be  the  obstruction  :  and  accordingly,  it  is  generally  necessary  to  counteract 
the  tendency  to  suffocation,  when  it  is  desired  to  prolong  the  life  of  the  animal 
after  this  operation,  by  making  an  opening  into  the  trachea.     Dr.  Reid  further 
ascertained,  that  the  application  of  a  stimulus  to  the  inferior  laryngeal  nerves, 
when  separated  from  the  trunk,  would  occasion  distinct  muscular  contractions 
in  the  larynx  j  whilst  a  corresponding  stimulus  applied  to  the  superior  laryngeal 
occasioned  no  muscular  movement,  except  in  the  crico-thyroid  muscle.     But 
when  the  superior  laryngeals  were  entire,  irritation  of  the  mucous  surface  of  the 
larynx,  or  of  the  trunks  themselves,  produced  contraction  of  the  glottis  and 
efforts  to  cough ;  effects  which  were  at  once  prevented  by  dividing  those  nerves, 

1  "Edinb.  Med.  and  Surg.  Journ."  Jan.  1838;  and  "  Anat.,  Pliysiol.  and  Tathol.  Res.," 
chap.  iv. 


518  OF  RESPIRATION. 

and  thereby  cutting  off  their  communication  with  the  Medulla  Oblongata. 
There  can  be  no  doubt,  then,  that  the  superior  and  inferior  laryngeal  branches 
constitute  the  circle  of  incident  and  motor  nerves,  by  which  the  aperture  of  the 
glottis  is  governed,  and  by  which  any  irritation  of  the  larynx  is  made  to  close 
the  passage,  so  as  to  prevent  the  entrance  of  improper  substances ;  whilst  the 
superior  laryngeal  nerve  also  excites  the  muscles  of  expiration,  so  as>to  cause 
the  violent  ejection  of  a  blast  of  air,  by  which  the  offending  gas,  fluid,  or  solid, 
may  be  carried  off.  The  effect  of  carbonic  acid  in  causing  spasmodic  closure  of 
the  glottis  is  well  known;  and  affords  a  beautiful  example  of  the  protective  office 
of  this  system  of  nerves.  The  mucous  surface  of  the  trachea  and  bronchi  appears, 
from  the  experiments  of  Valentin,  to  be  endowed  with  excitability,  so  that 
stimuli  applied  to  it  produce  expiratory  movements;  and  this  evidently  operates 
through  the  branches  of  the  pneumogastric  distributed  upon  the  membrane. 
Here,  as  elsewhere,  we  find  that  a  stimulus  applied  to  the  surface  has  a  much 
more  decided  influence  than  irritation  of  the  trunk  of  the  nerve  supplying  it. 
554.  The  actions  of  sighing,  yawning,  sobbing,  laughing,  coughing,  and 
sneezing,  are  nothing  else  than  simple  modifications  of  the  ordinary  movements 
of  respiration,  excited  either  by  mental  emotions,  or  by  some  stimulus  originating 
in  the  respiratory  organs  themselves. — Sighing  is  nothing  more  than  a  very 
long-drawn  inspiration,  in  which  a  larger  quantity  of  air  than  usual  is  made  to 
enter  the  lungs.  This  is  continually  taking  place  to  a  moderate  degree ;  and 
we  notice  it  particularly  when  the  attention  is  released,  after- having  been  fixed 
upon  an  object  which  has  excited  it  strongly,  and  which  has  prevented  our  feeling 
the  insufficiency  of  the  ordinary  movements  of  respiration.  Hence  this  action 
is  only  occasionally  Connected  with  mental  emotion. —  Yawning  is  a  still  deeper 
inspiration,  which  is  accompanied  by  a  kind  of  spasmodic  contraction  of  the 
muscles  of  the  jaw,  and  also  by  a  very  great  elevation  of  the  ribs,  in  which  the 
scapulae  partake.  The  purely  involuntary  character  of  this  movement  is  some- 
times seen,  in  a  remarkable  manner,  in  cases  of  palsy ;  in  which  the  patient 
cannot  raise  his  shoulder  by  an  effort  of  the  will,  but  does  so  in  the  act  of 
yawning.  Nevertheless  this  act  may  be  performed  by  the  will,  though  not 
completely ;  and  it  is  one  that  is  particularly  excited  by  an  involuntary  tendency 
to  imitation,  as  every  one  must  have  experienced  who  has  ever  been  in  company 
with  a  set  of  yawners. — Sobbing  is  the  consequence  of  a  series  of  short  convul- 
sive contractions  of  the  diaphragm  ;  and  it  is  usually  accompanied  by  a  closure 
of  the  glottis,  so  that  no  air  really  enters. — In  Hiccup,  the  same  convulsive 
respiratory  movement  occurs,  and  the  glottis  closes  suddenly  in  the  midst  of  it ; 
the  sound  is  occasioned  by  the  impulse  of  the  column  of  air  in  motion  against 
the  glottis. — In  Laughing,  a  precisely  reverse  action  takes  place  ;  the  muscles 
of  expiration  are  in  convulsive  movement,  more  or  less  violent,  and  send  out  the 
breath  in  a  series  of  jerks,  the  glottis  being  open.  This  sometimes  goes  on, 
until  the  diaphragm  is  more  arched,  and  the  chest  is  more  completely  emptied 
of  air,  than  it  could  be  by  an  ordinary  movement  of  expiration. — The  act  of 
Crying,  though  occasioned  by  a  contrary  emotion,  is,  so  far  as  the  respiration 
is  concerned,  very  nearly  the  same  as  the  last.  Every  one  knows  the  effect  of 
mixed  emotions,  in  producing  an  expression  of  them  which  is  "  between  a  laugh 
and  a  cry." — The  greater  part  of  the  preceding  movements  seem  to  belong  as 
much  to  the  consensual  or  to  the  emotional,  as  to  the  purely  reflex  group  of 
actions  ;  for  whilst  they  are  sometimes  the  result  of  peculiar  states  of  the  respi- 
ratory organs,  or  of  the  bodily  system  in  general,  they  may  also  be  called  forth 
by  influences  which  operate  directly  through  the  senses,  or  which  excite  the 
emotions.  Thus,  whilst  Sighing  and  Yawning  often  occur  as  simple' results  of 
deficient  aeration,  they  may  be  brought  on — the  former  by  a  depressed  state  of 
the  feelings — the  latter  by  the  mere  sight  of  the  act  in  another  person.  The 
actions  of  Laughter  and  Crying  seem  never  to  originate  in  the  respiratory  system; 


OF   THE   RESPIRATORY   MOVEMENTS.  519 

but  to  be  always  either  expressions  of  the  emotions,  or  simple  results  of  sensa- 
tions— as  when  crying  arises  from  the  sense  of  pain — and  laughter  from  that 
of  tickling.  The  origin  of  the  act  of  Hiccup  does  not  seem  very  clear ;  but  the 
movement  is  probably  of  a  purely  reflex  nature. 

555.  The  purposes  of  the  acts  of  Coughing  and  Sneezing  are,  in  both  instances, 
to  expel  substances  from  the  air-passages,  which  are  sources  of  irritation  there; 
and  this  is  accomplished  in  both,  by  a  violent  expiratory  effort,  which  sends 
forth  a  blast  of  air  from  the  lungs —  Coughing  occurs,  when  the  source  of  irrita- 
tion is  situated  at  the  back  of  the  mouth,  in  the  trachea,  or  bronchial  tubes. 
The  irritation  may  be  produced  by  acrid  vapours,  or  by  liquids  or  solids,  that 
have  found  their  way  into  these  passages  ;  or  by  secretions  which  have  been 
poured  into  them  in  unusual  quantity,  as  the  result  of  disease ;  or  by  the  simple 
entrance  of  air  (especially  if  cold),  when  the  membrane  is  in  a  peculiarly  irri- 
table state.     Any  of  these  causes  may  produce  an  impression  upon  the  excitor 
fibres  of  the  Pneumogastrics,  which,  being  conveyed  to  the  Medulla  Oblongata, 
gives  rise  to  the  transmission  of  motor  impulses  to  the  several  muscles,  that 
combines  them  in  the  act  of  coughing.     This  act  consists — 1st,  in  a  long  in- 
spiration, which  fills  the  lungs ;  2d,  in  the  closure  of  the  glottis  at  the  moment 
when  expiration  commences ;  and  3d,  in  the  bursting  open  (as  it  were)  of  the 
glottis,  by  the  violence  of  the  expiratory  movement;  so  that  a  sudden  blast  of 
air  is  forced  up  the  air-passages,  carrying  before  it  anything  that  may  offer  an 
obstruction. — The  difference  between  Coughing  and  Sneezing  consists  in  this — 
that  in  the  latter,  the  communication  between  the  larynx  and  the  mouth  is 
partly  or  entirely  closed  by  the  drawing  together  of  the  sides  of  the  velum 
palati  over  the  back  of  the  tongue ;  so  that  the  blast  of  air  is  directed,  more  or 
less  completely,  through  the  nose,  in  such  a  way  as  to  carry  off  any  source  of 
irritation  that  may  be  present  there. — It  is  difficult  to  say  how  far  these  actions 
are  simply  reflex;  or  how  far  they  may  require  the  stimulus  of  sensation  for  their 
performance. 

556.  Various  alterations  are  produced  in  the  lungs,  by  section  of  the  Pneu- 
mogastric  nerves  ;  and  it  has  been  supposed  that  these  exert  some  more  imme- 
diate and  direct  influence  over  the  condition  of  those  organs,  than  their  connec- 
tion with  the  respiratory  movements  will  serve  to  account  for.     The  inquiry 
into  the  nature  and  succession  of  these  changes  has  been  most  carefully  prose- 
cuted by  Dr.  J.  Reid  (Op.  cit.) ;  and  as  his   results  have  a  very  important 
bearing  on  several  physiological  and  pathological  questions  of  great  interest,  a 
summary  of  them  will  be  here  given. — In  the  first  place,  it  has  been  fully  estab- 
lished by  Dr.  Reid,  that  section  of  the  Yagus  on  one  side  only  does  not  neces- 
sarily, or  even  generally,  induce  disease  of  that  lung ;  and  hence  the  important 
inference  may  be  drawn,  that  the  nerve  does   not  exercise  any  immediate  influ- 
ence on  its  functions.     When  both  Vagi  are  divided,  however,  the  animal  rarely 
survives  long  ;  but  its  death  frequently  results  from  the  disorder  of  the  digestive 
functions.     Nevertheless,  the  power  of  digestion  is  sometimes  restored  suffi- 
ciently to  re-invigorate  the  animals ;  and  their  lives  may  then  be  prolonged  for 
a  considerable  time  (§  446).     In  fifteen  out  of  seventeen  animals  experimented 
on  by  Dr.  Reid,  the   lungs  were  found  more  or  less  unfit  for  the  healthy  per- 
formance of  their  functions.     The  most  common  morbid  changes  were  a  con- 
gested state  of  the  bloodvessels,  and  an  effusion  of  frothy  serum  into  the  air-cells 
and  bronchial  tubes.     In  eight  out  of  the  fifteen,  these  changes  were  strongly 
marked.     In  some  portions  of  the  lungs,  the  quantity  of  blood  was  so  great  as 
to  render  them  dense.     The  degree  of  congestion  varied  in  different  parts  of  the 
same  lung ;  but  it  was  generally  greatest  at  the  most  depending  portions.     The 
condensation  was  generally  greater  than  could  be  accounted  for  by  the  mere 
congestion  of  blood  in  the  vessels,  and  probably  arose  from  the  escape  of  the 
solid  parts  of  the  blood  into  the  tissue  of  the  lung.     In  some  instances  the  con- 


520  OF   RESPIRATION. 

densation  was  so  great,  that  considerable  portions  of  the  lungs  sank  in  water, 
and  did  not  crepitate ;  but  they  did  not  present  the  granulated  appearance  of 
the  second  stage  of  ordinary  pneumonia.  In  five  cases  in  which  the  animals 
had  survived  a  considerable  time  portions  of  the  lungs  exhibited  the  second,  and 
even  the  third  stages  of  pneumonia,  with  puriform  effusion  in  the  small  bron- 
chial tubes  ]  and  in  two,  gangrene  had  supervened. — One  of  the  most  important 
points  to  ascertain  in  an  investigation  of  this  kind,  is  the  first  departure  from  a 
liealthy  state ;  to  decide  whether  the  effusion  of  frothy  reddish  serum,  by  inter- 
fering with  the  usual  change  in  the  lungs,  causes  the  congested  state  of  the 
pulmonary  vessels  and  the  labored  respiration ;  or  whether  the  effusion  is  the 
effect  of  a  previously  congested  state  of  the  bloodvessels.  The  former  is  the 
opinion  of  many  physiologists,  who  have  represented  the  effusion  of  serum  as  a 
process  of  morbid  secretion,  directly  resulting  from  the  disorder  of  that  function 
produced  by  the  section  of  the  nerve ;  the  latter  appears  the  unavoidable  infer- 
ence from  the  carefully  noted  results  of  Dr.  Reid's  experiments.  In  several  of 
these,  only  a  very  small  quantity  of  frothy  serum  was  found  in  the  air-tubes, 
even  when  the  lungs  were  found  loaded  with  blood,  and  when  the  respiration 
before  death  was  very  labored.  This  naturally  leads  us  to  doubt,  whether  the 
frothy  serum  is  the  cause  of  the  labored  respiration,  and  of  the  congested  state 
of  the  pulmonary  vessels,  in  those  cases  where  it  is  present ;  though  there  can 
be  no  doubt  that,  when  once  it  is  effused,  it  must  powerfully  tend  to  increase 
the  difficulty  of  respiration,  and  still  further  to  impede  the  circulation  through 
the  lungs.  Dr.  R.  has  satisfied  himself  of  an  important  point  which  has  been 
overlooked  by  others,  namely,  that  this  frothy  fluid  is  not  mucus,  though  occa- 
sionally mixed  with  it,  but  that  it  is  the  frothy  serum  so  frequently  found  in  cases 
where  the  circulation  through  the  lungs  has  been  impeded  before  death.  From 
this  and  other  facts,  Dr.  R.  concludes  "  that  the  congestion  of  the  bloodvessels 
is  the  first  departure  from  the  healthy  state  of  the  lung,  and  that  the  effusion 
of  frothy  serum  is  a  subsequent  effect." — The  next  point,  therefore,  to  be  in- 
quired into,  is  the  cause  of  this  congestion ;  and  this  is  most  satisfactorily  ex- 
plained, in  accordance  with  the  general  laws  of  the  Circulation  (§  527),  by  re- 
membering that  section  of  the  Pneumogastrics  greatly  diminishes  the  frequency 
of  the  respiratory  movements,  and  that  the  quantity  of  air  introduced  into  the 
lungs  is,  therefore,  very  insufficient  for  the  due  aeration  of  the  blood.  There  is 
now  abundant  evidence,  in  regard  to  the  Pulmonary  circulation  in  particular, 
that,  to  prevent  the  admission  of  oxygen  in  the  lungs,  either  by  causing  the 
animal  to  breathe  pure  nitrogen  or  hydrogen,  or  by  occlusion  of  the  air-passages, 
is  to  bring  the  circulation  through  their  capillaries  to  a  speedy  check  (§  575). 
Hence  we  should  at  once  be  led  to  infer,  that  diminution  in  the  number  of  Re- 
spiratory movements  would  produce  the  same  effect ;  and  as  little  or  no  difference 
in  their  frequency  is  produced  by  section  of  one  Vagus  only,  the  usual  absence 
of  morbid  changes  in  the  lung  supplied  by  it  is  fully  accounted  for.  The  con- 
gestion of  the  vessels  induced  by  insufficient  aeration,  satisfactorily  accounts  not 
only  for  the  effusion  of  serum,  but  also  for  the  tendency  to  pass  into  the  inflam- 
matory condition,  sometimes  presented  by  the  lungs,  as  by  other  organs  similarly 
affected.  Dr.  Reid  confirms  this  view,  by  the  particulars  of  cases  of  disease  in 
the  human  subject,  in  which  the  lungs  presented  after  death  a  condition  similar 
to  that  observed  in  the  lower  animals  after  section  of  the  Vagi ;  and  in  these 
individuals,  the  respiratory  movements  had  been  much  less  frequent  than  natu- 
ral during  the  latter  part  of  life,  owing  to  a  torpid  condition  of  the  nervous 
centres.  The  opinion  (held  especially  by  Dr.  Wilson  Philip)  that  section  of 
the  Par  Vagum  produces  the  serous  effusion,  by  its  direct  influence  on  the  func- 
tion of  Secretion,  is  further  invalidated  by  the  fact  stated  by  Dr.  Reid,  that  he 
always  found  the  bronchial  membrane  covered  with  its  true  mucus,  except  when 
inflammation  was  present. — "The  experimental  history  of  the  Par  Vagum/'  it 


EFFECTS   OF   RESPIRATION   ON   THE   AIR.  521 

is  justly  remarked  by  Dr.  Reid,  "furnishes  an  excellent  illustration  of  the 
numerous  difficulties  with  which  the  physiologist  has  to  contend,  from  the 
impossibility  of  insulating  any  individual  organ  from  its  mutual  actions  and  re- 
actions, when  he  wishes  to  examine  the  order  and  dependence  of  its  phenomena." 
In  such  investigations,  no  useful  inference  can  be  drawn  from  one  or  two  ex- 
periments only;  in  order  to  avoid  all  sources  of  fallacy,  a  large  number  must 
be  made  ;  the  points  in  which  all  agree  must  be  separated  from  others  in  which 
there  is  a  variation  of  results ;  and  it  must  be  then  inquired,  to  what  the  latter 
is  due.1 

2.   Effects  of  Respiration  on  the  Air. 

557.  The  total  amount  of  air  which  can  be  drawn  into  the  Lungs  by  the 
deepest  possible  inspiratory  movement,  by  no  means  affords  a  measure  of  the 
quantity  which  they  ordinarily  contain.  It  is  in  fact  composed,  as  was  first 
pointed  out  by  Mr.  Julius  Jeffreys,2  of  several  different  quantities,  which  may 
be  distinguished  as  follows  : — 

1.  Residual  Air  ;  that  which  cannot  be  displaced  by  the  most  powerful  expi- 
ration, which  always  remains  in  the  thorax  so  long  as  the  lungs  retain  their 
natural  structure,  and  over  which,  therefore,  we  have  no  control. 

2.  Supplemental  Air ;  that  portion  which  remains  in   the  chest  after  the 
ordinary  gentle  expiration,  but  which  may  be  displaced  at  will. 

3.  Breathing  or  Tidal  Air;  that  volume  which  is  displaced  by  the  constant 
gentle  inspiration  and  expiration. 

4.  Complemental  Air ;   the  quantity  which  can  be  inhaled  by  the  deepest 
possible  inspiration,   over  and   above    that  which  is   introduced  in  ordinary 
breathing. 

The  amount  which  can  be  expelled  by  the  most  forcible  expiration  after  the 
fullest  inspiration,  and  which  is  consequently  the  sum  of  the  2d,  3d,  and  4th  of 
these  quantities,  is  designated  by  Dr.  Hutchinson3  as  the  Vital  Capacity,  being 
that  volume  of  air  which  can  be  displaced  by  living  movements.  This  "vital 
capacity"  is  less  dependent  than  might  have  been  supposed,  upon  the  absolute 
dimensions  of  the  thoracic  cavity,  being  yet  more  influenced  by  its  mobility. 
Thus  of  two  sets  of  men  of  the  same  height,  one  measuring  35  inches  around 
the  chest,  and  the  other  38  inches,  the  average  vital  capacity  of  the  first  was 
found  to  be  235  inches,  and  that  of  the  second  only  226  inches;  for  notwith- 
standing the  greater  absolute  capacity  indicated  by  the  larger  circumference  of 
the  latter,  the  inferior  mobility  of  their  chests  caused  more  "residual  air"  to 
remain  behind  after  the  deepest  expiration.  By  taking  the  average  of  nearly 
5000  observations,  Dr.  Hutchinson  has  arrived  at  the  very  remarkable  conclu- 
sion (Op.  cit.,  p.  1072),  that  of  all  the  elements  whose  variation  might  be  sup- 
posed to  affect  the  "vital  capacity,"  Height  alone  seems  to  have  any  constant 
relation  to  it ;  and  that  this  relation  is  capable  of  being  expressed  in  a  simple 
numerical  form.  The  following  table  represents  the  "vital  capacity"  regarded 

1  On  the  important  subject  of  the  Mechanism  of  Respiration,  the  following  Memoirs  may 
be  consulted  in  addition  to  those  already  referred  to :  Dr.  J.  Reid's  Art.  "  Respiration"  in 
"Cyclop,  of  Anat.  and  Physiol.";  Dr.  Hutchinson  in"  Med.-Chir.  Trans.,"  vol.  xxix. ;  Dr. 
Sibsonin  "Phil.  Trans.,"  1846,  "Med.  Gaz.,"  vol.  xli.,  "  Med.-Chir.  Trans.,"  vol.  xxxi., 
and  "Trans,  of  Prov.  Med.  Assoc.,"  1850;  Beau  and  Maissiat  in  "Archiv.  Gen.,"  1842  ; 
Mendelssohn,  "Der  Mechanismus  der  Respiration  und  Circulation,"  Berlin,  1845;  and 
Simon,  "Ueber  die  menge  der  ausgeathmeten  Luft  bei  verscheidenen  Meuschen,"  Giessen, 
1848. 

2  "Statics  of  the  Human  Chest,"  1843. 

3  "  Cyclop,  of  Anat.  and  Physiol,"  Art.  "  Thorax." 


522 


Or   RESPIRATION. 


U   i 

5 

I.         V  111 

1 

LU   (J   1 

5 

t.         JL    1 

2 

i. 

5 

2 

5 

3 

5 

3 

5 

4 

5 

4 

5 

5 

5 

5 

5 

6 

5 

6 

5 

7 

5 

7 

5 

8 

5 

8 

5 

.9 

5 

9 

5 

10 

5 

10 

5 

11 

5 

11 

6 

0 

by  Dr.  H.  as  necessary  to  health  at  the  middle  period  of  life,  in  the  Male  sex, 
for  each  inch  of  height  between  five  and  six  feet : — 

Height.  Vital  Capacity. 

174  cubic  in. 
182 
190 
198 
206 
214 
222 
230 
238 
246 
254 
262 

This  relation  may  be  briefly  expressed  by  the  rule,  that  for  every  inch  of  stature, 
from  five  to  six  feet,  eight  additional  cubic  inches  of  air  (at  60°  Fahr.)  are 
given  out  by  a  forced  expiration  after  a  full  inspiration. — There  is  also  a  rela- 
tion between  " vital  capacity"  and  Weight;  but  of  a  different  kind  from  that 
which  might  have  been  anticipated.  So  far  as  the  increase  in  weight  is  simply 
proportional  to  the  increase  in  height,  the  relation  is  of  course  the  same  for  the 
one  as  for  the  other.  But  if  the  excess  of  weight  should  depend  upon  corpu- 
lence, the  vital  capacity  decreases  in  a  very  marked  manner,  being  always  very 
low  in  corpulent  men.  The  general  result  of  Dr.  Hutchinson's  observations 
on  this  point  is  expressed  by  him  as  follows  :  When  the  man  exceeds  the  average 
weight  (at  each  height)  by  7  per  cent.,  the  vital  capacity  decreases  1  cub.  in. 
per  Ib.  for  the  next  35  Ibs.  above  this  weight. — The  influence  of  Age  upon  the 
"vital  capacity"  is  less  marked  than  might  have  been  anticipated.  The  general 
fact  seems  to  be,  that  the  "vital  capacity"  undergoes  a  slight  increase  between  15 
to  35  years,  and  then  gradually  decreases,  the  decline  being  more  rapid  than  the 
augmentation,  so  that  by  the  age  of  66  it  has  diminished  to  about  4-5ths  of  the 
maximum. — There  does  not  seem  to  be  as  close  a  relation  between  the  "  vital 
capacity"  and  Muscular  Vigor,  as  might  &  priori  have  been  expected,  and  as  an 
attempt  has  been  made  to  establish.1  Cases  are  not  unfrequent  in  which  men 
of  athletic  constitution  have  an  absolute  deficiency,  whilst  others  by  no  means 
remarkable  for  physical  power  present  a  large  excess.2  In  fact,  as  Dr.  R.  Hall 
has  justly  remarked,  this  measure  indicates,  not  what  a  person  does  breathe,  but 
what  he  can  breathe. — The  maximum  "  vital  capacity"  met  with  by  Dr.  Hutch- 
inson,  in  his  entire  series  of  observations,  was  464  cub.  in. ;  this  was  in  a  man  7 
feet  high,  whose  weight  was  308  Ibs.  The  minimum  was  only  46  cub.  in. ;  this 
was  in  a  dwarf  (Don  Francisco)  whose  height  was  only  29  inches,  and  weight 
40  Ibs. 

558.  But  however  constant  the  above  averages  may  prove  to  be,  when  tested 
by  a  still  larger  number  of  observations,  it  yet  remains  to  be  determined  within 
what  limits  individual  variation  may  range,  without  departure  from  the  standard 
of  health.  It  is  considered  by  Dr.  Hutchinson  (Op.  cit.  p.  1079)  that  a  defi- 
ciency of  16  per  cent,  (unless  the  individual  should  be  very  corpulent)  should 
excite  suspicion  of  disease;  but  the  observations  of  Dr.  C.  R.  Hall  (loc.  cit.) 
seem  to  show  that  the  range  is  considerably  wider,  especially  in  females.  They 
also  indicate  that  even  a  marked  deficiency  in  vital  capacity  must  not  be  re- 
garded as  indicative  of  pulmonary  disease ;  for  it  may  be  dependent  upon  dis- 
order of  the  abdominal  viscera,  especially  upon  congested  liver. 


1  See  Dr.  Jackson  in  "Philadelphia  Medical  Examiner,"  1851,  p.  51. 

2  See  Dr.  Radclyffe  Hall  in  "Trans,  of  Prov.  Med.  and  Surg.  Assoc.,"  1851. 


EFFECTS   OF  RESPIRATION    ON   THE   AIR.  523 

559.  In  estimating,  however,  the  effects  of  the  Respiratory  function  upon 
the  air  which  passes  through  the  lungs,  we  are  not  so  much  concerned  with  the 
quantity  which  may  be  drawn  in  and  forced  out,  as  with  that  actually  exchanged 
at  each  movement.  There  are  many  difficulties  in  arriving  at  any  exact  con- 
clusion upon  this  point  ;  and  hence  it  happens  that  the  estimates  of  those  who 
have  inquired  into  it  are  singularly  discrepant.  The  following  are  the  amounts 
assigned  by  some  of  the  most  recent  experimenters. 

Herbst1  .....         .         .  20—30  cnbic  inches. 

Valentin2  .......  14—92 

Vierordt8  .         .         .         ...         .  10—42 

Coatkupe<  .......  16 


If  we  take  20  cubic  inches  as  the  average  quantity  exchanged  at  each  respi- 
ration, we  cannot  but  observe  how  small  a  proportion  it  bears  to  the  entire 
amount  which  the  lungs  usually  contain  ;  for  the  ft  residual  volume,"  which 
cannot  be  expelled,  is  estimated  by  Dr.  Hutchinson  at  from  75  to  100  cubic 
inches,  and  the  "reserve  volume,"  which  can  only  be  expelled  by  a  forced  expi- 
ration, is  about  as  much  more  ;  the  sum  of  the  two  being  from  150  to  200  cub. 
in.,  or  from  7  J  to  10  times  the  "  breathing  volume."  Now  it  is  obvious  that 
if  no  provision  existed  for  mingling  the  air  inspired  with  the  air  already  occu- 
pying the  lungs,  the  former  would  penetrate  no  further  than  the  larger  air- 
passages  ;  and  as  this  would  be  again  thrown  out  at  the  next  expiration,  the 
bulk  of  the  air  contained  in  the  lungs  would  remain  altogether  without  renewal, 
and  the  expired  air  would  not  be  found  to  have  undergone  any  change.6  That 
a  change  is  effected,  however,  in  the  whole  volume  of  the  air  contained  in  the 
lungs,  with  every  inspiration,  is  indicated  by  the  difference  between  the  inspired 
and  expired  air  ;  and  this  change  must  be  attributed  to  the  "mutual  diffusion" 
of  gases,  these  (as  discovered  by  Prof.  Graham)  tending  to  interpenetrate  one 
another,  when  of  different  densities  or  of  different  temperatures. 

560.  The  total  amount  of  air  which  passes  through  the  Lungs  in  twenty-four 
hours,  will  of  course  vary  with  the  extent  and  frequency  of  the  respiratory 
movements  ;  and  these  are  liable  to  be  affected  by  many  circumstances,  but 
particularly  by  the  relative  degrees  of  repose  and  of  exertion.  Moreover,  as 
any  such  computation  must  be  based  upon  the  datum  of  the  ordinary  volume 
of  breathing  or  "  tidal"  air,  it  is  obvious  that  the  estimates  of  different  observers 
must  vary  with  the  amount  they  adopt.  Thus  Mr.  Coathupe's  estimate  of  the 
diurnal  total  is  460,800  cub.  in.,  or  366£  cubic  feet;  that  of  Vierordt,  from  his 
observations  on  his  own  person  in  a  state  of  rest,  is  530,026  cub.  in.,  or  306f 
cub.  feet,  but  this,  when  corrected  (by  Scharling's  experiments)  for  a  moderate 
amount  of  exertion,  would  be  raised  to  624,087  cub.  in.,  or  361  cub.  feet;  and 
that  of  Valentin  is  as  high  as  688,348  cub.  in.,  or  398  J  cub.  feet.  —  It  is  of 
great  practical  importance  to  determine  the  quantity  of  air  which  ought  to  be 
allowed  for  consumption  by  individuals  confined  in  prisons,  work-houses,  schools, 
&c.  ;  and  for  this,  experience  seems  to  have  fixed  800  cubic  feet  as  the  minimum 
that  can  be  safely  assigned,  except  where  extraordinary  provisions  are  in  opera- 
tion for  its  constant  renewal  by  ventilation.  The  evil  consequences  of  an  insuf- 
ficient supply  of  air  will  be  noticed  hereafter  (Sect.  3). 

1  '  Meckel's  Arcliiv.,"  1828. 

2  'Lehrbuch  der  Physiologie,"  band  i.  p.  538. 

3  'Wagner's  Handworterbuch,"  band  ii.  p.  835. 

4  'Philosophical  Magazine,"  1839,  vol.  xiv.  p.  401. 

5  'Cyclop,  of  Anat.  and  Phys.,"  vol.  iv.  p,  1067. 

6  See  Mr.  Jeffreys's  "Statics  of  the  Human  Chest,"  in  which  this  important  point  first 
received  due  consideration. 


524  OF   RESPIRATION. 

561.  The  alterations  in  this  air  which  are   effected  by  Respiration,  mainly 
consist  in  the  removal  of  a  portion  of  its   Oxygen,  and  the  substitution   of  a 
quantity  of  Carbonic  acid,  usually  rather  less  in  bulk  than  the  oxygen  which 
has  disappeared.      The  proportion  of  the   air  thus  changed  appears  to  vary 
according  to  the  frequency  of  the  respirations.     Thus  Vierordt1  found  that,  if  he 
only  respired  six  times  in  a  minute,  the  quantity  of  Carbonic  acid  was  5.5  per 
cent,  of  the  whole  air  exhaled;  with  twelve  respirations,  it  was  4.2;  with  twenty- 
four,  it  was  3.3  ;  with  forty-eight,  it  was  3.0;  and  with  ninety-six,  it  was  2.6 
per  cent.     In  some  of  the  experiments  of  Messrs.  Allen  and  Pepys,  it  was  as 
much  as  8  per  cent.     Probably  about  4.35  per  cent,  may  be  taken  as  the  average, 
at  the  ordinary  rate  of  respiration. — It  appears,  however,  from  the  researches 
of  the  last-named  experimenters,  that,  if  the  air  be  already  charged  in  some 
degree  with  Carbonic  acid,  the  quantity  exhaled  is  much  less ;  for,  when  300 
cubic  inches  of  air  were  respired  for  three  minutes,  only  28  £  cubic  inches  (9$ 
per  cent.)  of  carbonic  acid  were  found  in  it;  although  the  previous  rate  of  its 
production,  when  fresh  air  was  taken  in  at  every  respiration,  was  32  cubic  inches 
in  a  minute.     Knowing,  then,  the  necessity  of  a  free  excretion  of  carbonic  acid, 
we  are  led  by  this  fact  to  perceive  the  high  importance  of  ventilation ;  for  it  is 
not  sufficient  for  health,  that  a  room  should  contain  the  quantity  of  air  requisite 
for  the  support  of  its  inhabitants  during  a  given  time ;  since  after  they  have 
remained  in  it  but  a  part  of  that  time,  the  quantity  of  carbonic  acid  which  its 
atmosphere  will  contain,  will  be  large  enough  to  interfere  greatly  with  the  due 
aeration  of  their  blood,  and  will  thus  cause  oppression  of  the  brain,  and  the 
other  morbid  affections  that  result  from  the  accumulation  of  carbonic  acid  in  the 
circulating  fluid. — It  appears  from  the  experiments  of  Dr.  Snow,  that  the  pre- 
sence of  Carbonic  acid  in  the  atmosphere  acts  more  deleteriously  upon  the  sys- 
tem, in  proportion  as  the  normal  quantity  of  Oxygen  has  been  reduced.      He 
found  that  birds  and  mammalia,  introduced  into  an  atmosphere  containing  only 
from  10J  to  16  per  cent,  of  oxygen,  soon  died,  although  means  were  taken  to 
remove  the  carbonic  acid  set  free  by  their  respiration,  as  fast  as  it  was  formed ; 
whilst,  on  the  other  hand,  an  increase  in  the  proportion  of  carbonic  acid  to  12 
or  even  20  per  cent. — the  percentage  of  oxygen  being  kept  to  its  regular  standard 
of  21  per  cent. — did  not  appear  to  enfeeble  the  vital  actions  more  rapidly  than 
did  the  reduction  of  the  oxygen  in  the  experiments  just  referred  to.     Dr.  Snow 
concludes  from  his  experiments  on  the  lower  animals,  that  5  or  6  per  cent,  of 
carbonic  acid  cannot  exist  in  an  atmosphere  respired  by  Man,  without  danger  to 
life ;  and  that  less  than  half  this  amount  will  soon  be  fatal,  when  it  is  formed 
at  the  expense  of  the  oxygen  of  the  air.2 

562.  The  reaction  which  thus  takes  place  between  the  Air  and  the  Blood,  is 
partly  explicable  upon  physical  principles.     If  the  blood  come  to  the   lungs 
charged  with  Carbonic  acid,  and  be  exposed  in  their  cells  to  the  influence  of  at- 
mospheric air,  which  is  a  mixture  of  Oxygen  and  Nitrogen,  an  endosmose  and 
exosmose  of  gases  will  take  place.3     The  carbonic  acid  of  the  blood  will  pass  out, 
to  be  replaced  by  oxygen  and  nitrogen ;  and  the  quantity  of  the  former  which 
enters  will  be  much  greater  than  that  of  the  latter,  on  account  of  the  superior 
facility  with  which  oxygen  passes  through  porous  membranes.     If  the  venous 

1  "Physiologie  des  Athmens,"  pp.  102-149. 

2  "Edinb.  Med.  and  Surg.  Journal,"  1846. 

3  See  "  Princ.  of  Phys.,  Gen.  and  Comp.,"  g  495,  Am.  Ed. — It  has  been  recently  affirmed 
by  Dr.  Bence  Jones  ("Medical  Times,"  1851,  p.  169),  that  the  law  of  the  "  diffusion  of  gases" 
does  not  apply  to  the  respiration  of  air-breathing  animals :  since  a  gas  is  on  one  side  of  the 
septum  and  a  liquid  on  the  other.     But  it  was  long  since  shown  by  Dr.  Mitchell  of  Phila- 
delphia, that  the  tendency  to  mutual  diffusion  and  replacement  exists  between  atmospheric 
nir  and  gases  dissolved  in  water;   and  that  this  is  not  prevented  by  the  interposition  of  a 
permeable  membrane. 


EFFECTS    OF  RESPIRATION   ON   THE   AIR.  525 

blood  also  contain  nitrogen  as  well  as  carbonic  acid,  this  also  will  pass  out,  to 
be  replaced  by  the  oxygen  of  the  air.  Thus,  there  will  be  a  continual  exosmose 
of  carbonic  acid  and  nitrogen,  and  a  continual  endosmose  of  oxygen  and  nitro- 
gen.'— The  exhalation  and  absorption  of  Nitrogen  appear  usually  to  balance  each 
other,  so  that  the  amount  of  this  gas  in  the  respired  air  undergoes  little  change ; 
a  slight  increase  in  the  Nitrogen  of  the  expired  air  being  the  alteration  most 
constantly  noticed.  But  the  case  is  different  in  regard  to  the  exchange  of  Car- 
bonic acid  and  Oxygen.  According  to  the  law  of  "mutual  diffusion  "  of  gases, 
the  volume  of  Oxygen  that  is  taken  in,  should  exceed  that  of  the  Carbonic  acid 
which  passes  out,  in  the  proportion  of  1174  to  1000  ;  and  it  has  been  attempted 
by  Valentin  and  Brunner1  to  show,  that,  if  a  reasonable  allowance  be  made  for 
accidental  causes  of  disturbance,  this  is  the  actual  proportion  between  the  Oxygen 
absorbed  and  the  Carbonic  acid  given  out,  as  indicated  by  experiment.  Such, 
however,  cannot  be  the  case,  since  the  departures  are  too  wide  to  be  accounted 
for  on  this  hypothesis.  Still  there  appears  to  the  Author  no  adequate  reason 
for  doubting  that  the  process  of  exchange  is  mainly  effected  by  the  force  of  "  mu- 
tual diffusion  •"  the  result  of  its  action,  however,  being  determined  by  a  great 
number  of  modifying  conditions ;  so  that  the  formula  which  expresses  the  law 
of  its  action  in  those  simplest  cases,  in  which  the  result  is  determined  solely  by 
the  tendency  to  mutual  penetration  between  gases  on  the  opposite  sides  of  a 
porous  septum  that  affords  them  free  passage,  can  scarcely  hold  good  when  the 
septum  is  a  moist  animal  membrane,  through  which  these  gases  pass  with  very 
different  degrees  of  facility,  and  when  one  side  of  it  is  in  contact  with  the  liquid, 
through  which  they  are  diffusible  with  different  degrees  of  readiness. 

563.  The  recent  experiments  of  MM.  Regnault  and  Reiset3  appear  to  have 
furnished  the  solution  of  the  wide  differences  in  the  estimates  which  various 
experimenters  have  given,  as  to  the  relative  amount  of  Oxygen  absorbed  and  of 
Carbonic  acid  exhaled;  by  showing  that  it  depends — not,  as  Dulong  and  Des- 
pretz  supposed,  upon  the  ordinary  regimen  of  the  animal  (the  proportion  of 
oxygen  absorbed  being  much  larger  in  Carnivora  than  in  Herbivora) — but  upon 
the  nature  of  the  aliment  on  which  the  animal  is  fed  at  the  time  of  the  experi- 
ment. Animals  fed  on  flesh  absorb  much  more  oxygen  in  proportion,  than  those 
fed  on  a  vegetable  diet ;  thus  in  a  dog  exclusively  nourished  on  flesh,  the  pro- 
portion of  oxygen  absorbed,  to  100  parts  of  carbonic  acid  exhaled,  was  134.3,  or 
much  above  that  which  the  law  of  mutual  diffusion  would  indicate ;  whilst  in  a 
rabbit  fed  exclusively  upon  vegetable  food,  the  proportion  of  oxygen  absorbed 
was  only  109.34  to  100  parts  of  carbonic  acid  exhaled,  or  less  than  the  calculated 
amount.  The  difference  between  the  relative  proportions  of  surplus  Oxygen,  in 
the  same  animal,  under  opposite  circumstances,  was  found  to  be  as  much  as 
62  :  104.  These  experimenters  further  ascertained  that,  when  an  animal  is 
kept  fasting,  the  relation  between  the  Oxygen  absorbed  and  the  Carbonic  acid 
exhaled  is  nearly  the  same  as  when  the  animal  is  fed  on  flesh  j  the  reason  ap- 
parently being,  that  in  the  former  case  the  animal's  respiration  is  kept  up  at  the 
expense  of  the  constituents  of  its  own  body,  which  corresponds  with  animal 
food  in  their  composition.  There  can  be  no  doubt  that,  on  the  whole,  a  con- 
siderable surplus  of  oxygen  is  absorbed  into  the  system ;  and  it  appears  pro- 
bable that  a  part  of  this  additional  oxygen  is  made  to  combine  with  hydrogen 
furnished  by  the  food  or  by  the  disintegration  of  the  tissues,  the  water  thus 
generated  forming  part  of  that  exhaled  from  the  lungs ;  whilst  another  part  will 
be  applied  to  the  oxidation  of  the  Sulphur  and  Phosphorus,  which  are  taken  in 
as  such  in  the  food,  and  which,  after  forming  part  of  the  solid  tissues,  are  ex- 
creted in  the  condition  of  sulphuric  and  phosphoric  acids,  chiefly  through  the 

1  Valentin's  "  Lehrbuch  de  Physiologic,"  band  i.  pp.  507-580. 

2  "  Annales  de  Chimie  et  de  Physique,"  1849. 


526  OF    RESPIRATION. 

kidneys.  It  also  appears,  from  the  recent  experiments  of  Dr.  Bence  Jones,1 
that  the  action  of  oxygen  is  exerted  in  the  system  upon  Ammonia,  and  probably 
upon  other  products  of  decomposition  of  the  nitrogenous  tissues,  in  such  a 
manner  as  to  produce  Nitrous  or  Nitric  acid,  which  makes  its  appearance  in 
the  urine. 

564.  The  absolute  quantity  of  Carbonic  Acid  exhaled  from  the  Lungs  is  liable 
to  variation  from  so  many  sources,  that  no  fixed  standard  can  be  assigned  for  it. 
The  mean  of  a  great  number  of  observations,  however,  made  in  different  modes, 
and  under  different  circumstances,  would  give  about  160  grains  of  Carbon  per 
hour  as  the  amount  set  free  by  a  well-grown  adult  man,  under  ordinary  circum- 
stances. Taking  this  as  the  average  of  the  twenty-four  hours,  the  total  quantity 
of  Carbon  thus  daily  expired  from  the  Lungs  would  be  3840  grains,  or  8  oz.  Troy. 
The  chief  causes  of  variation  are — the  Temperature  of  the  surrounding  Medium, 
Age,  Sex,  Development  of  the  body,  state  of  Health  or  Disease,  Muscular  Ex- 
ertion or  Repose,  Sleep  or  Watchfulness,  Period  of  the  Day,  and  state  of  the 
Digestive  process.  These  will  now  be  considered  in  detail. 

a.  Temperature  of  'surrounding  Medium. — The  amount  of  Carbonic   Acid 
exhaled  by  warm-blooded  animals  is  greatly  increased  by  external   Cold,  and 
diminished  by  Heat;  as  is  shown  by  the  following  results  of  comparative  ex- 
periments upon  the  quantity  set  free  by  the  same  animals,  at  low,  medium,  and 
high  temperatures,  in  periods  of  an  hour  (Letellier3)  : — 

Tern,  about  32°.  Tern.  59°— 68°.  Tern.  86°— 106°. 

Grammes.  Grammes.  Grammes. 

A  Canary  .       '  .'".',  .  0.325  0.250  0.129 

A  Turtle-Dove   ..       ..  .  0.974  0.684  0.336 

Two  Mice       ':.'     V  .  0.531  0.498  0.268 

A  Guinea-Pig     .  .' „ '•'!'  .  3.006  2.080  1.453 

From  this  table  it  appears  that  the  quantity  of  carbonic  acid  exhaled  by  Mam- 
mals between  86°  and  106°  is  less  than  half  that  set  free  near  the  freezing- 
point;  whilst  that  which  is  exhaled  between  59°  and  68°  is  but  little  more  than 
two-thirds  of  the  same  amount.  The  diminution  occasioned  by  heat  is  still 
more  remarkable  in  Birds  which  exhale  at  the  highest  temperature  scarcely  more 
than  one-third  of  that  set  free  at  the  lowest. — The  observations  of  Vierordt3 
upon  himself  show  that  the  same  is  true  of  the  Human  subject ;  a  difference  of 
10°  Fahr.,  according  to  him,  producing  a  variation  of  rather  more  than  two 
cubic  inches  in  the  amount  of  Carbonic  Acid  hourly  expired. 

b.  Age. — The  amount  of  Carbonic  Acid  exhaled  increases  in  both  sexes  up  to 
about  the  thirtieth  year ;  it  remains  stationary  until  about  the  forty-fifth  ;  and 
then  diminishes.     The  following  are  the  comparative  results  of  experiments 
upon  males  of  different  ages,  and  of  a  moderate  degree  of  muscular  development 
(Andral  and  G-avarret4)  : — 

Carbon  exhaled  Carbon  exhaled 

Age.  per  hour.  Age.  per  hour. 


8  years 
12     " 
14     " 
20     " 
26     " 


77.0  grains.  37  years  164.7  grains. 

113.9     "  48     "  161.7     " 

126.2  "  59     "  154.0     " 

166.3  "  68     "  147.8     " 

169.4  «  76     "  92.4     " 


c.  Sex. — At  all  ages  beyond  eight  years,  the  exhalation  is  greater  in  Males 
than  in  Females.  Nearly  the  same  proportionate  increase  takes  place,  however, 
in  Females,  up  to  the  time  of  puberty ;  when  the  quantity  abruptly  ceases  to 

1  "  Philosophical  Transactions,"  1851 ;  and  "  Medical  Times,"  Aug.  30,  1851. 

2  "  Annales  de  Chimie  et  de  Physique,"  1845. 

3  "Physiologic  des  Athmens,"  pp.  73-82. 

4  "  Annales  de  Chimie  et  de  Physique,"  1843. 


EFFECTS   OF  RESPIRATION   ON    THE   AIR.  527 

increase,  and  remains  stationary  as  long  as  they  continue  to  menstruate.  When, 
however,  menstruation  has  ceased,  the  exhalation  of  carbonic  acid  begins  again 
to  augment ;  and  then  again  diminishes,  with  the  advance  of  years,  as  in  men. 
Should  menstruation  temporarily  cease  at  any  time,  the  exhalation  of  carbonic 
acid  immediately  undergoes  an  increase,  precisely  as  at  the  final  cessation  of  the 
function.  And  during  pregnancy,  the  exhalation  increases  in  like  manner. 
The  following  table  of  the  comparative  respiration  of  Females  at  different  ages 
will  serve  at  the  same  time  for  comparison  with  the  preceding,  so  as  to  exhibit 
the  general  difference  between  the  two  sexes,  at  ages  nearly  corresponding ;  and 
also  to  indicate  the  peculiar  modifications  induced  by  the  operations  of  the  geni- 
tal system  (Andral  and  Gavarret)  : — 

Carbon  exhaled  Carbon  exhaled 

Age.  per  hour.  Age.  ,     . ,      per  hour. 

10  years     .         .       92.4  grains. 
13     «         .    •     .       97.0     « 

During  Menstrual  life.  During  Pregnancy. 

15£  years  .         .       97.0  grains.  22  years     .         .     129.3  grains. 

26       "      .         .       97.0     "  32     "         .         .     126.7     " 

32       "      .         .       95.4     "  42     "        .         .     120.3     " 
45       "      .        .       95.4     « 

After  Cessation  of  Catamenia. 

38  years    .         .     120.3  grains.  66  years     .         ,     104.7  grains. 

49     "        .         .     113.9     "  76     "         .         .     101.4     * 

52     «        .         .     115.5     «  82     "        .         .       92.4     " 

56     "        .         .     119.3     " 

d.  Development  of  the  Body. — The  more  robust  the  individual,  casteris  part- 
busj  the  more  carbonic  acid  is  exhaled ;  and  the  variation  is  much  more  influ- 
enced by  the  development  of  the  muscular  system,  than  by  the  height  or  weight, 
capacity  of  the  chest,  &c.     Thus,  a  very  strong  man   of  twenty-six  years  of 
age  exhaled  at  the  rate  of  217.1  grains  per  hour;  when  a  man  of  moderate 
muscular  power  set  free  but  169.4  grains  in  the  same  time.     Another  robust 
man  of  sixty  years  of  age  exhaled  at  the  rate  of  209.4  per  hour;  another  of 
similar  constitution,  and  sixty-three  years  of  age,  at  the  rate  of  190.9  grains 
per  hour  ;  and  an  old  man  of  ninety-two  years,  who  still  preserved  an  uncommon 
degree  of  energy,  and  who  in  his  younger  days  had  boasted  of  extraordinary 
muscular  powers,  exhaled  at  the  rate  of  135.5   grains  per  hour.     So,  also,  a 
remarkably  vigorous  young  woman  of  nineteen  years  exhaled  at  the  rate  of  107.8 
grains  per  hour ;  another  of  twenty-two  years,  rather  less  powerful,  at  the  rate 
of  103.1  grains;  and  a  strong  woman  of  forty-four  years  (who  had  ceased  to 
menstruate)   152.4  grains. — On  the  other  hand,  a  slender  man  of  forty-five 
years,  in  the  enjoyment  of  good  health,  only  exhaled  at  the  rate  of  132.4  grains 
per  hour  (Andral  and  Gavarret). 

e.  State  of  Health  or  Disease. — Upon  this  very  important  cause  of  variation 
few  accurate  researches  have  yet  been  made.     The  percentage  of  carbonic  acid 
in  the  expired  air  has  been  found  to  be  unusually  great  in  the  Exanthemata, 
and  in  chronic  Skin-diseases  (Macgregor1)  ;  and  it  has  been  stated  to  be  dimin- 
ished in  Typhus  (Malcolm3). — Thus,  the  average  proportion  in  health  being 
about  4.3  per  cent.  (Vierordt)  ;  it  has  been  seen  at  8  per  cent,  in  confluent  Small- 
pox, at  5  per  cent,  in  Measles,  and  at  7.2  per  cent,  in  a  severe  case  of  Ichthyosis 
which  terminated  fatally ;  whilst  in  Typhus  the  percentage  has  been  found  to 
range  from  1.18  to  2.50.     But  these  statements  do  not  indicate  the  total  quan- 
tity exhaled  in  each  case. — The  remarkable  increase  of  the  exhalation  in  cases 

1  "Edinb.  Monthly  Journal,"  1843.  2  "Report  of  Brit.  Assoc.,"  1843,  p.  87. 


528  OF   RESPIRATION. 

of  Chlorosis,  has  been  already  noticed  ;  in  four  cases  recorded  by  Hannover,  the 
hourly  expiration  was  123.6,  118.6,  116.9,  and  106.3  grains;  the  absolute  quan- 
tity diminishing  as  the  respirations  increased  in  rapidity.  —  In  chronic  diseases  of 
the  respiratory  organs,  as  might  be  anticipated,  the  amount  of  Carbonic  acid 
exhaled  undergoes  a  sensible  diminution  (Nysten1  and  Hannover3).  —  Further 
researches  are  much  needed  on  this  subject  ;  but,  for  obvious  reasons,  they  cannot 
be  readily  made  in  severe  forms  of  disease. 

f.  Muscular  Exertion  or  Repose.  —  The  effect  of  bodily  exercise,  in  moderation, 
is  to  produce  a  considerable  increase  in  the  amount  of  carbonic  acid  exhaled, 
both  during  its  continuance,  and  for  some  little  time  subsequently  to  its  cessa- 
tion. According  to  the  observations  of  Vierordt,  the  increase  amounts  to  one- 
third  of  the  quantity  exhaled  during  rest  ;  and  it  lasts  for  more  than  an  hour 
afterwards,  being  manifested  in  the  greater  quantity  of  air  respired,  and  in  the 
larger  -percentage  of  carbonic  acid  contained  in  it.  If  the  exercise  be  prolonged, 
however,  so  as  to  occasion  fatigue,  it  is  succeeded  by  a  diminished  exhalation. 
—  The  connection  between  muscular  exertion  and  the  exhalation  of  carbonic 
acid,  is  most  remarkably  shown  in  Insects  ;  in  which  animals  we  may  witness  the 
rapid  transition  between  the  opposite  conditions  of  extreme  muscular  exertion, 
and  tranquil  repose  ;  and  in  which  the  effects  of  these  upon  the  respiratory  pro- 
cess are  not  masked  by  that  exhalation  of  carbonic  acid,  which  is  required  in 
warm-blooded  animals  simply  for  the  maintenance  of  a  fixed  temperature.  Thus 
a  Humble-Bee  was  found  by  Mr.  Newport3  to  produce  one-third  of  a  cubic  inch 
of  carbonic  acid,  in  the  course  of  a  single  hour,  during  which  its  whole  body  was 
in  a  state  of  constant  movement,  from  the  excitement  resulting  from  its  capture  ; 
and  yet,  during  the  whole  twenty-four  hours  of  the  succeeding  day,  which  it 
passed  in  a  state  of  comparative  rest,  the  quantity  of  carbonic  acid  generated 
by  it  was  absolutely  less. 

g.  Sleep  or  watchfulness.  —  The  amount  of  carbonic  acid  exhaled  during  sleep 
is  considerably  less  than  that  set  free  in  the  waking  state.  This  is  particularly 
shown  by  the  experiments  of  Scharling  ;4  who  confined  the  subjects  of  them 
in  an  air-tight  chamber,  within  which  they  could  sleep,  take  their  meals,  &c. 
Thus  in  one  case,  the  hourly  exhalation  sank  from  160  to  100,  in  another  from 
194.7  to  122.3,  and  in  another  from  99  to  75.1.  The  cause  of  this  result  is 
partly  to  be  sought  in  the  cessation  of  all  muscular  exertion  (save  that  concerned 
in  the  maintenance  of  the  respiration)  ;  and  partly  in  the  diminution  in  the  dis- 
sipation of  the  heat  of  the  body  itself. 

h.  State  of  the  Digestive  Process.  —  It  is  well  established,  that  the  exhalation 
of  carbonic  acid  is  greatly  increased  by  eating,  and  that  it  is  diminished  by 
fasting.  Thus  Prof.  Scharling  states  the  hourly  exhalation  to  have  increased 
in  one  instance  from  145  to  190,  after  breakfast  and  a  walk  j  in  another  from 
140  to  177,  after  breakfast  alone  ;  and  in  another  from  111.9  to  188.9,  after 
dinner.  The  observations  of  Vierordt  are  to  the  same  effect.  —  It  is  remarkable 
that  Alcoholic  drinks  have  a  tendency  to  diminish  the  exhalation  of  carbonic 
acid,  especially  when  taken  into  an  empty  stomach  ;  and  it  appears  from  the 
experiments  of  Dr.  Prout,5  which  have  been  confirmed  as  to  many  points  by 
those  of  Vierordt,  that  this  diminution  continues  so  long  as  the  alcohol  remains 
unconsumed  in  the  system,  and  is  then  followed  by  a  marked  increase  in  the 
percentage  of  carbonic  acid  in  the  inspired  air  ;  showing  that  the  presence  of 
alcohol  tends  to  prevent  the  normal  oxidation  and  elimination  of  the  excrementi- 


R6cherches  de  Physiologie  et  de  Chimie  Patliologique,"  18-11. 

De  Quantitate  relativa  et  absoluta  Acidi  Carbonic!  ab  Homine  Sano  et  JEgroto 


exhalati,"  1845. 


Phil  os.  Transact.,"  1836. 

Ann.  der  Chem.  und  Pharm.,"  1843  ;  transl.  in  "  Ann.  de  Claim,  et  de  Plays.,"  1843. 

Thomson's  Annals  of  Philosophy,"  vols.  ii.  and  iv. 


EFFECTS   OF  RESPIRATION   ON   THE   AIR.  529 

tious  matters  which  the  blood  may  contain.  Strong  tea  is  said  to  have  the  same 
effect  (Prout,  Vierordt). — The  quantity  is  also  decreased  by  depressing  affections 
of  the  mind  (Prout,  Vierordt,  and  Scharling). 

i.  Period  of  the  Day. — Independently  of  these  variations,  which  have  their 
source  in  the  condition  of  the  individual,  there  is  reason  to  believe  that  there  is 
a  diurnal  cycle  of  change  in  the  quantity  of  carbonic  acid  exhaled,  the  maximum 
being  (cseteris  paribus)  before  and  after  noon,  and  the  minimum  before  and  after 
midnight.  From  the  experiments  of  Scharling  upon  the  Human  subject,  it 
would  appear  that  the  average  proportion  exhaled  by  day  to  that  exhaled  by 
night,  is  as  1J  to  1 ;  and  this  difference  does  not  seem  to  be  affected  by  sleep  or 
wakefulness.  How  far  it  is  to  be  accounted  for  by  other  differences  in  the  con- 
dition of  the  system,  it  does  not  seem  easy  to  determine.  But  it  is  pretty  ob- 
viously associated  with  a  difference  in  the  power  of  generating  heat ;  for  accord- 
ing to  the  observations  of  Chossat  (CHAP,  xin.),  there  is  a  like  diurnal  variation 
in  the  temperature  of  Birds  ;  and  most  persons  are  conscious  of  a  greater  difficulty 
in  bearing  exposure  to  cold  between  midnight  and  early  morning,  than  at  any 
other  period  in  the  twenty-four  hours. 

565.  The  aeration  of  the  blood  may  take  place,  not  only  by  means  of  the 
Lungs,  but  also  in  some  degree  through  the  medium  of  the  Cutaneous  surface. 
In  some  of  the  lower  tribes  of  animals,  indeed,  this  is  a  very  important  part  of 
their  respiratory  process :  and  even  in  certain  Vertebrata,  the  cutaneous  respira- 
tion is  capable  of  supporting  life  for  a  considerable  time.     This  is  especially  the 
case  in  the  Batrachia,  whose  skin  is  soft,  thin,  and  moist ;  and  the  effect  is  here 
the  greater,  since,  from  the  small  proportion  of  the  blood  that  has  passed  through 
the  lungs,  that  which  circulates  through  the  system  is  very  imperfectly  arterial- 
ized.     By  the  experiments  of  Bischoff  it  was  ascertained  that,  even  after  the 
lungs  of  a  Frog  had  been  removed,  a  quarter  of  a  cubic  inch  of  carbonic  acid 
was  exhaled  from  the  skin,  during  eight  hours.     Experiments  which  have  been 
made  on  the  Human  subject  leave  no  room  for  doubt,  that  a  similar  process  is 
effected  through  the  medium  of  his  general  surface,  although  in  a  very  inferior 
degree ,  for  by  confining  the  body  in  a  close  chamber,  into  which  the  products 
of  cutaneous  respiration  could  freely  pass,  whilst  the  pulmonary  respiration  was 
measured  by  a  distinct  apparatus,  Prof.  Scharling1  ascertained  that  the  propor- 
tion of  carbonic  acid  given  off  by  the  Skin  is  from  l-30th  to  l-60th   of  that 
exhaled  from  the  Lungs  during  the  same  period  of  time.     Moreover,  it  has  been 
observed,  not  unfrequently,  that  the  livid  tint  of  the  skin  which  supervenes  in 
Asphyxia,  owing  to  the  non-arterialization  of  the  blood  in  the  lungs,  has  given 
place  after  death  to  the  fresh  hue  of  health,  owing  to  the  reddening  of  the  blood 
in  the  cutaneous  capillaries  by  the  action  of  the  atmosphere  upon  them  ]  and  it 
does  not  seem  improbable  that,  in  cases  of  obstruction  to  the  due  action  of  the 
lungs,  the  exhalation  of  carbonic  acid  through  the  skin  may  undergo  a  consider- 
able increase ;  for  we  find  a  similar  disposition  to  vicarious  action  in  other  parts 
of  the  excreting  apparatus.     Moreover,  there  is  evidence  that  the  interchange 
of  gases  between  the  air  and  the  blood,  through  the  skin,  has  an  important 
share  in  keeping  up  the  temperature  of  the  body  (CHAP,  xm.) ;  and  we  find  the 
temperature  of  the  surface  much  elevated  in  many  cases  of  pneumonia,  phthisis, 
&c.,  in  which  the  lungs  seem  to  perform  their  function  very  insufficiently. 

566.  The  total  amount  of  Carbonic  acid  daily  given  off  from  the  Skin  and 
Lungs  may  be  estimated  in   another  mode ;  namely,  by  determining  the  total 
amount  of  Carbon  contained  in  the  ingesta,  and  the  amount  excreted  in  other 
ways,  making  allowance  for  the  difference  in  weight  (if  any)  of  the  body.     In 
this  mode,  Prof.  Liebig  came  to  the  conclusion  that  the  average  amount  of  car- 
bon exhaled  by  soldiers  in  barracks,  was  13.9  oz  (Hessian)  or  very  nearly  14  oz. 

1  "  Ann.  der  Chem.  und  Pharm.,"  1846. 
34 


530  OF   RESPIRATION. 

troy.1  From  similar  collective  observations  upon  the  inmates  of  the  Bridewell 
at  Marienschloss  (a  prison  where  labor  is  enforced),  he  calculates  that  each  in- 
dividual exhaled  10.5  oz.  of  carbon  daily  in  the  form  of  carbonic  acid ;  while 
in  a  prison  at  G-iessen,  whose  inmates  are  deprived  of  all  exercise,  the  daily 
average  was  but  8.5  oz.3  It  has  been  shown  by  Prof.  Scharling,3  that  the  total 
amount  of  carbon  contained  in  the  daily  allowance  of  food  and  drink  in  the 
Danish  Navy,  is  somewhat  less  than  10.5  oz. ;  and  as  we  shall  presently  see 
that  from  l-10th  to  l-12th  of  the  carbon  ingested  passes  off  through  other  chan- 
nels, scarcely  more  than  9.5  oz.  of  this  amount  can  be  consumed  by  the  respi- 
ratory process. — A  very  exact  estimate,  though  based  on  more  limited  data,  has 
been  recently  made  by  M.  Barral  j§  who  experimented  upon  himself  (set.  29) 
in  winter  (A)  and  in  summer  (B),  upon  a  boy  of  6  years  old  (c),  upon  a  man 
of  59  years  old  (D),  and  upon  an  unmarried  woman  of  32  years  (E).  The  fol- 
lowing table  gives  the  results  which  he  obtained,  from  an  average  of  five  days, 
in  regard  to  the  disposal  of  the  Carbon  of  the  food ;  those  which  relate  to  its 
Hydrogen  and  Oxygen  will  be  noticed  hereafter  (§  569). 

Weight  of  Body.      Carbon  of  Food.  Carbon  excreted. 

In  Fecee.  In  Urine.  By  Exhalation. 

A     104.5  Ibs.         5654.1  grs.               236.2  grs.  234.6  grs.  5183.3  grs. 

B 4090.0   "                137.4    "  211.5   "  3741.1    « 

C       33        "          2382.3    "                 149.7    "             67.9    "  2164.7    " 

D     129.1    «           5123.0    "                 210.0    "  327.3    "  4585.7    " 

E     134.6    "          4520.8   "                  64.8   "  216.1    "  4239.9    " 

Thus  the  average  amount  of  carbon  daily  consumed  in  pulmonary  and  cutaneous 
exhalation  by  M.  Barral  himself,  was  in  winter  5183.3  grains,  or  10.8  oz.  troy ; 
whilst  in  summer  it  was  but  3741.1  grains,  or  7.8  oz.  troy ;  this  difference  is 
quite  conformable  to  what  might  have  been  anticipated  from  the  results  of  a 
different  mode  of  experimenting  (§  564,  a)  j  and  it  throws  some  light  on  the 
discrepancies  in  the  results  of  other  measurements,  to  find  that  the  seasonal 
variation  is  scarcely  less  than  one-third  of  the  mean  between  these  two  amounts. 
The  other  results  correspond  closely  with  the  statements  of  MM.  Andral  and 
G-avarret,  in  regard  to  the  higher  proportion  of  carbonic  acid  exhaled  (as  com- 
pared with  the  bulk  of  the  body)  by  children  ;•  and  the  smaller  proportion  thrown 
off  by  men  advanced  in  years,  and  by  women. 

567.  It  is  not  only  by  an  oxygenated  atmosphere,  that  the  removal  of  Car- 
bonic acid  from  the  blood  may  be  effected.  For  although  it  was  formerly  sup- 
posed that  the  exhaled  carbonic  acid  is  generated  in  the  lungs  by  the  combina- 
tion of  atmospheric  oxygen  with  the  carbonaceous  matters  of  the  blood,  and  that 
the  inhalation  of  oxygen  is  therefore  immediately  necessary  for  its  production, 
yet  it  is  now  quite  certain  that  this  carbonic  acid  exists  preformed  in  venous 
blood,  and  that  the  oxygen  introduced  is  carried  into  the  arterial  circulation, 
instead  of  being  at  once  returned  to  the  air  in  the  state  of  carbonic  acid.  That 
this  (which  was  first  advanced  by  Lagrange  and  Hassenfratz)  is  the  true  view 
of  the  case,  is  proved  by  experiments  of  two  kinds  ; — those,  namely,  which  have 
shown  that  a  larger  proportion  of  oxygen  exists  in  arterial  blood,  and  a  larger 
proportion  of  carbonic  acid  in  venous  blood  (§  163)  ; — and  those  which  demon- 

1  "  Animal  Chemistry,"  3d  edit.  p.  13.     The  mode  in  which  this  estimate  was  made, 
however,  was  very  far  from  exact ;  as  it  rests  on  the  assumption  that  the  carbon  of  the 
feces  and  urine  was  no  more  than  equal  to  that  of  certain  extra  articles  of  diet  supposed 
to  have  been  consumed,  and  that  all  the  carbon  of  the  regular  allowance  of  bread,  meat, 
and  vegetables,  must  have  passed  off  by  the  atmosphere.    Its  great  discordance  with  other 
results  leaves  little  room  for  doubt,  that,  even  if  not  far  from  being  true  for  the  particular 
case,  it  cannot  be  admitted  as  representing  the  usual  average. 

2  Op.  cit,,  p.  46.  3  «  Ann.  der  Chem.  und  Pharm.,"  1846. 
4  "Ann.  de  China,  et  de  Phys.,''  torn.  xxv. 


EFFECTS   OF   RESPIRATION   ON   THE   AIR.  531 

strate  that  an  exhalation  of  carbonic  acid  may  continue  for  a  considerable  period 
(in  cold-blooded  animals  especially),  during  which  the  animal  is  breathing  an 
atmosphere  in  which  no  oxygen  exists.  Thus  it  was  shown  by  Spallanzani,1 
that  Snails  might  be  kept  for  a  longtime  in  Hydrogen,  without  apparent  injury 
to  them }  and  that  during  this  period  they  disengaged  a  considerable  amount 
of  Carbonic  acid.  Dr.  Edwards3  subsequently  ascertained  that,  when  Frogs 
were  kept  in  hydrogen  for  several  hours,  the  quantity  of  carbonic  acid  exhaled 
was  fully  as  great  as  it  would  have  been  in  atmospheric  air,  or  even  greater ; 
this  latter  fact,  if  correct,  may  be  accounted  for  by  the  superior  displacing 
power  which  (on  the  laws  of  the  diffusion  of  gases)  hydrogen  possesses  for  car- 
bonic acid.  Collard  de  Martigny3  repeated  this  experiment  in  Nitrogen,  with 
the  same  results.  In  both  sets  of  experiments,  the  precaution  was  used  of  com- 
pressing the  flanks  of  the  animal,  previously  to  immersing  it  in  the  gas,  so  as  to 
expel  from  the  lungs  whatever  mixture  of  oxygen  they  might  contain.  These 
experiments  have  been  since  repeated  by  Miiller  and  Bergemann,  who  took  the 
additional  precaution  of  removing,  by  means  of  the  air-pump,  all  the  atmospheric 
air  that  the  lungs  of  the  frog  might  previously  contain,  together  with  the  car- 
bonic acid  that  might  exist  in  the  alimentary  canal.  They  found,  in  one  of 
their  experiments,  that  the  quantity  of  carbonic  acid  exhaled  in  hydrogen  was 
nearly  a  cubic  inch  in  6i  hours;  and,  in  another,  that  nearly  the  same  amount 
was  given  off  in  nitrogen,  though  this  required  rather  a  longer  period.  It  ap- 
pears from  the  table  of  their  results,4  that  the  amount  was  not  ordinarily  greater 
in  the  experiments  which  were  prolonged  for  twelve  or  fourteen  hours,  than  in 
those  which  were  terminated  in  half  the  time ;  hence  it  may  be  inferred  that 
the  quantity  which  the  blood  is  itself  capable  of  disengaging  is  limited,  and  that 
the  absorption  of  oxygen  is  necessary  to  enable  carbonic  acid  to  be  set  free  from 
the  body. — It  is  impossible,  however,  for  an  adult  Bird  or  Mammal  to  sustain 
life  for  any  considerable  time  in  an  atmosphere  deprived  of  oxygen ;  since  the 
greatly-increased  rapidity  and  energy  of  all  their  vital  operations,  necessitate  a 
much  more  constant  supply  of  this  vivifying  agent  than  is  needed  by  the  inferior 
tribes ;  and,  as  we  shall  presently  see,  the  capillary  action  requisite  for  the  pas- 
sage of  the  blood  through  the  lungs  will  not  take  place  without  it.  But  Dr. 
Edwards  has  shown,  that  young  Mammalia  can  sustain  life  in  an  atmosphere  of 
hydrogen  or  nitrogen,  for  a  sufficient  length  of  time  to  exhale  a  sensible  amount 
of  carbonic  acid ;  so  that  the  character  of  the  process  is  clearly  proved  to  be  the 
same  in  them  as  in  Reptiles  and  Invertebrata. 

568.  Much  discussion  has  taken  place  with  regard  to  the  degree  in  which  the 
proportion  of  Nitrogen  in  the  air  is  affected  by  Respiration.  It  seems  probable 
that  the  absorption  and  exhalation  of  this  gas  are  continually  taking  place ;  but 
that  the  two  amounts  usually  nearly  balance  each  other.5  On  the  whole,  how- 
ever, there  is  adequate  reason  to  believe  that  Nitrogen  is  usually  given  off;  this 
being  the  joint  result  of  the  analysis  of  the  expired  air,  and  of  the  comparison 
of  the  Nitrogen  given  off  in  the  other  excretions  with  that  ingested  as  a  con- 
stituent of  the  food.  Of  the  experiments  made  in  the  former  of  these  methods, 
the  most  accurate. are  those  of  MM.  Regnault  and  Reiset,  whose  general  conclu- 
sions are  as  follows :  (1.)  That  warm-blooded  animals  subjected  to  their  ordi- 
nary regimen  exhale  nitrogen,  but  never  in  larger  proportion  than  l-50th,  and 
sometimes  in  less  than  l-100th,  of  the  oxygen  consumed :  (2.)  That  in  a  state 
of  inanition,  animals  usually  absorb  nitrogen :  (3.)  That  animals  whose  usual 

1  "Memoires  sur  la  Respiration,"  traduits  par  Senebier,  Geneve,  1804. 

2  De  1' Influence  des  Agens  Physiques  sur  la  Vie  ;"  Paris,  1824. 

3  "Recherches  Experinientales,"  &c.  in  Magendie's  "Journal  de  Physiologie,"  torn.  x. 

4  Mailer's  "Elements  of  Physiology,"  translated  by  Baly,  p.  338. 

5  For  the  considerations  which  render  this  probable,  see  especially  Dr.  W.  F.  Edwards, 
"  On  the  Influence  of  Physical  Agents  on  Life,"  Part  iv.  chap.  xvi.  sect.  2r  3. 


Urine. 

Teces.            Lungs  and  Skin. 

168.3  grs. 

43.2  grs. 

220.8  grs. 

151.3    « 

20.1    " 

155.9    « 

47.8    « 

27.8    " 

46.3    « 

234.6    " 

38.6    " 

148.3    " 

154.4    » 

12.3    « 

179.1    " 

532  OF   RESPIRATION. 

diet  has  been  changed,  usually  absorb  oxygen  until  they  are  accustomed  to  their 
new  food.1 — Of  the  experiments  made  according  to  the  second  method,  those  of 
M.  Boussingault  upon  turtle-doves,  and  those  of  M.  Barral  upon  the  human 
subject,  appear  to  be  trustworthy.  The  former  states  that  the  surplus  of  nitro- 
gen in  the  food  of  the  bird,  above  that  excreted  by  the  kidneys  and  intestinal 
canal,  is  2£  grains  daily;3  whilst  the  latter  gives  the  following  as  the  results  of 
his  observations  upon  himself  and  the  other  individuals  already  referred  to 
(§  566) :- 

Nitrogen  in  Food.  Nitrogen  excreted. 

A  .  432.3  grs. 

B  327.3    " 

C  121.9    " 

D  421.5    " 

E  345.8    " 

In  cases  A,  B,  and  E,  the  amount  of  Nitrogen  which  (being  otherwise  unac- 
counted for)  must  be  considered  to  have  passed  off  by  the  lungs  and  skin,  was 
about  l-75th  of  the  oxygen  consumed;  a  proportion  which  accords  very  well 
with  that  deduced  by  MM.  Regnault  and  Reiset  from  their  experiments  on 
animals.  In  case  D,  however,  it  was  only  l-97th ;  and  in  case  c  (that  of  a  child 
of  six  years  old),  it  was  as  little  as  l-143d. — It  will  be  remembered  that  Nitro- 
gen exists  in  an  uncombined  state  in  the  blood  (§  163) ;  its  percentage,  how- 
ever, is  continually  varying ;  and  no  constant  difference  is  observable  between 
the  proportions  yielded  by  arterial  and  venous  blood  respectively. 

[The  alterations  effected  in  the  Blood  by  Respiration  have  already  been  fully 
considered.  See  §§  163-166.] 

569.  Exhalation  and  Absorption  through  the  Lungs. — The  Air  expired  from 
the  lungs  differs  from  that  which  was  introduced  into  them,  not  merely  in  the 
altered  proportions  of  its  Oxygen,  Nitrogen,  and  Carbonic  acid,  but  also  in  hav- 
ing received  (under  ordinary  circumstances  at  least)  a  large  addition  to  its 
watery  vapor.  This  it  doubtless  acquires,  in  accordance  with  physical  laws, 
through  its  exposure  to  the  warm  blood  which  is  spread  out  over  a  very  exten- 
sive surface,  the  intermediate  membrane  being  extremely  permeable ;  and  the 
variations  in  its  amount  will  depend  upon  the  physical  conditions  under  which 
that  exposure  takes  place.  The  air  expired  in  ordinary  respiration  is  charged 
with  as  much  watery  vapor  as  saturates  it  at  the  temperature  of  the  body ;  and 
consequently  the  amount  of  watery  vapor  thus  exhaled,  will  vary  (for  equal 
volumes  of  air  at  any  given  temperature)  in  the  inverse  proportion  to  that  which 
the  air  previously  contained.  But  when  the  air  is  very  cold  and  very  dry,  and 
the  respiration  is  unusually  rapid,  it  may  not  remain  sufficiently  long  in  the  air- 
cells  to  be  raised  to  the  temperature  of  the  body,  or  to  be  fully  saturated  with 
moisture.  The  amount  of  watery  vapor  exhaled,  moreover,  will  of  course 
depend  in  part  upon  the  quantity  of  air  which  passes  through  the  lungs.  And 
from  these  causes  of  variation,  it  happens  that  the  amount,  of  watery  vapor 
exhaled  in  twenty-four  hours  ranges  from  about  6  to  27  oz. ;  its  usual  range, 
however,  being  between  16  and  20  oz. — Of  the  fluid  ordinarily  exhaled  with 
the  breath,  a  part  doubtless  proceeds  from  the  moist  lining  of  the  nostrils,  fauces, 
&c. ;  but  it  is  indisputable  that  the  greater  proportion  of  it  comes  from  the  lungs, 
since,  when  the  respiration  is  entirely  performed  through  a  canula  introduced 
into  the  trachea,  the  amount  of  watery  vapor  which  the  breath  contains  is  still 
very  considerable.  Of  the  proper  pulmonary  exhalation,  there  can  be  no  doubt 
that  the  greater  part  is  the  mere  surplus-water  of  the  blood,  and  especially  of 

1  "Ann.  de  Chim.  et  de  Phys.,"  1849.  2  "Comptes  Rendus,"  1846. 


Oxygen  exhaled. 

Equiv.  of  Hydrogen. 

Hydrogen  exhaled. 

Ji  ' 

3841.4  grs. 

480.2  grs. 

801.3  grs. 

B 

2757.6    " 

344.7    " 

597.5    " 

C 

1880.6    " 

235.1    " 

330.4    « 

D 

3795.1    " 

474.4    « 

662.3    « 

EXHALATION   AND   ABSORPTION   THROUGH   THE  LUNGS.         533 

the  crude  fluid  which  has  been  newly  introduced  into  the  circulating  current 
by  the  process  of  nutritive  absorption.  But  there  is  strong  evidence  that  Hydro- 
gen as  well  as  carbon  undergoes  combustion  in  the  system ;  and  that  a  portion 
of  the  exhaled  aqueous  vapor  is  the  product  of  that  combustion.  For  of  the 
hydrogen  which  the  food  contains,  not  more  than  from  l-8th  to  l-10th  passes 
off  by  the  other  excretions,  the  remaining  7-8ths  Or  9-10ths  being  exhaled  in 
the  condition  of  watery  vapor  from  the  lungs.  A  portion  of  the  oxygen  which 
this  vapor  contains,  is  supplied  by  the  food ;  but  there  is  a  considerable  surplus 
of  hydrogen ;  and  this  can  only  be  converted  into  water,  at  the  expense  of  oxy- 
n  derived  from  the  atmosphere.  Upon  this  point  the  experiments  of  M.  Barral 
loc.  cit.)  gave  the  following  results. 

Difference. 
321.1  grs. 

252.8  " 
95.3    " 

187.9  « 
E         3140.5    «                   392.5    «                  643.8    «                  251.3    " 

Thus  it  appears  that,  of  the  Hydrogen  exhaled  from  the  lungs  and  skin  of  M. 
Barral,  in  the  condition  of  watery  vapor,  not  less  than  321.1  grs.  in  winter, 
and  252.8  grains  in  summer,  must  have  been  converted  into  water  by  oxygen 
derived  from  the  air ;  and  this  calculation  would  give  2889.9  grs.  (6  oz.  troy) 
for  the  winter,  and  2275.2  grs.  (4.7  oz.  troy)  for  the  summer,  as  the  amount  of 
water  thus  generated  in  the  combustive  process.  This,  however,  can  only  be 
regarded  as  an  approximation  to  the  truth ;  since  there  are  many  circumstances 
not  taken  into  account  in  the  computation,  by  which  the  estimate  may  be 
affected. 

570.  The  fluid  thrown  of  from  the  lungs  is  not  pure  Water.  It  holds  in 
solution,  as  might  have  been  expected,  a  considerable  amount  of  carbonic  acid, 
and  also  some  animal  matter ;  the  exact  nature  of  the  latter,  which  according  to 
Collard  de  Martigny  (op.  cit.)  constitutes  about  3  parts  in  1000,  has  not  been 
ascertained ;  but  from  the  recent  inquiries  of  Mr.  R.  A.  Smith,1  it  would  appear 
to  be  an  albuminous  substance  in  a  state  of  decomposition.  If  the  fluid  be  kept 
in  a  closed  vessel,  and  be  exposed  to  an  elevated  temperature,  a  very  evident 
putrid  odor  is  exhaled  by  it.  Every  one  knows  that  the  breath  itself  has  occa- 
sionally in  some  persons,  and  constantly  in  others,  a  fetid  taint ;  when  this  does 
not  proceed  from  carious  teeth,  ulcerations  in  the  air-passages,  disease  in  the 
lungs,  or  other  similar  causes,  it  must  result  from  the  excretion  of  the  odorous 
matter,  in  combination  with  watery  vapor,  from  the  pulmonary  surface.  That 
this  is  the  true  account  of  it  seems  evident,  from  the  analogous  phenomenon  of 
the  excretion  of  turpentine,  camphor,  alcohol,  and  other  odorous  substances, 
which  have  been  introduced  into  the  venous  system,  either  by  natural  absorption 
or  by  direct  injection ;  and  also  from  the  suddenness  with  which  it  often  mani- 
fests itself,  when  the  digestive  apparatus  is  slightly  disordered,  apparently  in 
consequence  of  the  entrance  of  some  mal-assimilated  matter  into  the  blood. 
Among  the  substances  occasionally  thrown  of  by  the  lungs,  phosphorus  deserves 
a  special  mention,  on  account  of  the  peculiarity  of  the  form  under  which  it  is 
eliminated  :  for  it  has  been  found  that  if  phosphorus  be  mixed  with  oil,  and  be 
injected  into  the  bloodvessels,  it  partly  escapes  in  an  unoxidized  state  from  the 
lungs,  rendering  the  breath  luminous.3  And  this  luminous  breath  has  also 
been  observed  in  spirit-drinkers  j  in  whom  the  oxidation  of  the  effete  matters 
of  the  system  is  impeded,  in  consequence  of  the  demand  set  up  by  the  alcohol 
ingested  for  the  oxygen  introduced  (§  564,  Ti). 

1  "Philosophical  Magazine,"  vol.  xxx.  p.  478. 

2  "Casper's  Wochenschrift,"  1849,  band  15. 


534  OF   ABSORPTION. 

571.  Not  only  exhalation,  but  also  (under  peculiar  circumstances)  absorption 
of  fluid  may  take  place  through  the  Lungs.     Thus  Dr.  Madden1  has  shown  that, 
if  the  vapour  of  hot  water  be  inhaled  for  some  time  together,  the  total  loss  by 
exhalation  is  so  much  less  than  usual,  as  to  indicate  that  the  cutaneous  trans- 
piration is   partly  counterbalanced  by  pulmonary  absorption;   the  pulmonary 
exhalation  being  at  the  same  time  entirely  checked.     It  is  probable  that,  if  the 
quantity  of  fluid  in  the  blood  had  been  previously  diminished   by  excessive 
sweating,  or  by  other  copious  fluid  secretions,  the  pulmonary  absorption  would 
have  been  much  greater.     Still,  in  the  cases  formerly  mentioned  (§  469),  in 
which  a  large  increase  in  weight  could  only  be  accounted  for  on  the  supposition 
of  absorption  of  water  from  the  atmosphere,  it  seems  probable  that  the  cutaneous 
surface  was  chiefly  concerned;  for  it  can  only  be  when  the  air  introduced  into 
the  lungs  is  saturated  with  watery  vapor,  that  the  usual  exhalation  will  be 
checked,  or  that  any  absorption  can  take  place. 

572.  That  absorption  of  other  volatile  matters  diffused  through  the  air,  is, 
however,  continually  taking  place  by  the  lungs,  is  easily  demonstrated.     A 
familiar  example  is  the  effect  of  the  inhalation  of  the  vapor  of  Turpentine  upon 
the  urinary  excretion.     It  can  only  be    in  this  manner  that  those  gases  act 
upon  the  system,  which  have  a  noxious  or  poisonous  effect,  when  mingled  in 
small  quantities  in  the  atmosphere;  and  it  is  most  astonishing  to  witness  the 
extraordinary  increase  in  potency  which  many  substances  exhibit,  when  they 
are  brought  into  relation  with  the  blood  in  the  gaseous  form.     The  most  re- 
markable example  of  this  Idnd  is  afforded  by  Arseniuretted  Hydrogen,  the  in- 
spiration of  a  few  hundredths  of  a  grain  of  which  has  been  productive  of  fatal 
consequences,  the  resulting  symptoms  being  those  of  arsenical  poisoning.     Next 
to  this,  perhaps,  in  deleterious  activity,  is  Sulphuretted  Hydrogen  ;  but  it  would 
seem  that  the  effects  of  this  upon  the  Human  subject  are  scarcely  so  violent  as 
they  are   upon  animals ;   for  though  it  has  been  found  that  the  presence  of 
l-1500th  part  of  it  in  the  respired  air  will  destroy  a  bird  in  a  very  short  time, 
that  l-800th  part  suffices  to  kill  a  dog,  and  that  l-250th  part  is  fatal  to  a  horse, 
yet  M.  Parent-Duchatelet  has  affirmed  that  workmen  habitually  breathe  with 
impunity  an  atmosphere  containing  one  per  cent.,  and  that  he  himself  has  re- 
spired, without  serious  symptoms  ensuing,  air  which  contained  three  per  cent. 
There  can  be  no  doubt,  however,  that  the  continued  inhalation  of  air  thus  contami- 
nated, would  be  speedily  fatal.     Sulphuretted  hydrogen  and  Hydro-sulphuret  of 
ammonia  are  given  off  from  most  forms  of  decaying  animal  and  vegetable  matter ; 
and  it  is  undoubtedly  to  the  accumulation  of  these  gases,  that  the  fatal  results 
which  sometimes   ensue  from   entering  sewers  are  to  be  chiefly  attributed. — 
Carburetted  hydrogen  is  another  gas  whose  effects  are  similar ;  but  a  larger  pro- 
portion of  it  is  required  to  destroy  life. — Carbonic  acid  gas,  also,  appears  to  be 
absorbed  by  the  lungs,  when  a  large  proportion  of  it  is  contained  in  the  atmo- 
sphere.    The  accumulation  of  this  gas  in  the  blood,  when  the  respired  air  is 
charged  with  it  even  to  a  moderate  amount,  might  be  attributed  to  the  impedi- 
ment thus  offered  to  its  ordinary  exhalation  (§  56) :  but  the  following  experiment 
appears  to  prove  that  it  may  be  actually  absorbed  into  the  blood,  and  that  it 
will  thus  exert  a  real  poisonous  influence,  and  not  merely  produce  an  asphyxiat- 
ing effect.     It  was  found  by  Rolando,  that  the  air-tube  of  one  lung  of  the  land- 
tortoise  may  be  tied,  without  apparently  doing  any  material  injury  to  the  animal, 
as  the  respiration  performed  by  the  other  is  sufficient  to  maintain  life  for  some 
time  ;  but,  having  contrived  to  make  a  tortoise  inhale  carbonic  acid  by  one  lung, 
whilst  it  breathed  air  by  the  other,  he  found  that  the  animal  died  in  a  few  hours.2 

1  "Prize  Essay  on  Cutaneous  Absorption,"  p.  55. 

2  The  fatal  result  of  breathing  the  fumes  of  charcoal  is,  therefore,  not  simple  Asphyxia, 
such  as  would  result  from  breathing  hydrogen  or  nitrogen. — Other  volatile  products  are  set 


EFFECTS    OF    SUSPENSION    OR   DEFICIENCY    OF   RESPIRATION.       535 

— Cyanogen  is  another  gas  which  has  an  actively-poisonous  influence  upon 
animals,  when  absorbed  into  the  lungs ;  its  agency,  also,  is  of  a  narcotic 
character. 

573.  It  is  singular  that  the  effects  of  the  respiration  of  pure  Oxygen  should 
not  be  dissimilar.     At  first,  the  rapidity  of  the  pulse  and  the  number  of  the 
respirations  are  increased,  and  the  animal  appears  to  suffer  little  or  no  incon- 
venience for  an  hour ;  but  symptoms  of  coma  then  gradually  develop  themselves, 
and  death  ensues  in  six,  ten,  or  twelve  hours.     If  the  animals  are  removed  into 
the  air  before  the  insensibility  is  complete,  they  then  quickly  recover.  When  the 
body  is  examined,  the  heart  is  seen  beating  strongly,  while  the  diaphragm  is 
motionless;  the  whole  blood  in  the  veins,  as  well  as  in  the  arteries,  is  of  a  bright 
scarlet  color ;  and  several  of  the  membranous  surfaces  have  the  same  tint.     The 
blood  is  observed  to  coagulate  with  remarkable  rapidity  ;  and  it  is  to  the  altera- 
tion in  its  properties,  occasioned  by  hyper-arterialization,  and  indicated  by  this 
condition,  that  we  are  probably  to  attribute  the  fatal  result.     There  can  be  no 
doubt  that  in  this  instance,  an  undue  amount  of  oxygen  is  absorbed ;  and  it  does 
not  seem  unlikely  that  one  cause  of  the  fatal  result,  is  a  stagnation  of  the  blood 
in  the  systemic  capillaries,  consequent  upon  the  want  of  sufficient  change  in  its 
passage  through  them.     When  Nitrogen  or  Hydrogen  is  breathed  for  any  length 
of  time,  death  results  from  the  deprivation  of  Oxygen,  rather  than  from  any 
deleterious  influence  which  these  gases  themselves  exert.     Death  is  also  caused 
by  the  inhalation  of  several  gases  of  an  irritant  character,  such  as  Sulphurous, 
Nitrous,  and  Muriatic  acids ;  but  it  is  doubtful  how  far  they  are  absorbed,  or 
how  far  their  injurious  effects  are  due  to  the  abnormal  action  which  they  excite 
in  the  lining  membrane  of  the  air-cells  and  tubes.     It  cannot  be  doubted,  that 
Miasmata  and  other  morbific  agents  diffused  through  the  atmosphere,  are  more 
readily  introduced  into  the  system  through  the  pulmonary  surface  than  by  any 
other;  and  our  aim  should,  therefore,  be  directed  to  the  discovery  of  some  coun- 
teracting agents,  which  can  be  introduced  in  the  same  manner.     The  Pulmonary 
surface  affords  a  most  advantageous  channel  for  the  introduction  of  certain  medi- 
cines that  can  be  raised  in  vapor,  when  it  is  desired  to  affect  the  system  with 
them  speedily  and  powerfully ;  such  is  pre-eminently  the  case  with  those  Anaes- 
thetic agents,  ether  and  chloroform,  whose  introduction  into  the  various  depart- 
ments of  Medical  and  Surgical  practice  constitutes  a  most  important  era  in  the 
history  of  the  healing  art ;   also  with  Mercury,1  Iodine,  Tobacco,  Stramonium, 
&c. 

3. — Effects  of  Suspension  or  Deficiency  of  Respiration. 

574.  We  have  now  to  consider  the  results  of  the  cessation  of  the  Respiratory 
function,  and  the  consequent  retention  of  Carbonic  Acid  in  the  blood.     If  this 
be  sufficiently  prolonged,  a  condition  ensues,  to  which  the  name  of  Asphyxia 
has  been  given ;  the  essential  character  of  which  is  the  cessation  of  muscular 
movement,  and  shortly  afterwards  of  the  circulation;  with  an  accumulation  of 
blood  in  the  venous  system.     The  time  which  is  necessary  for  life  to  be  de- 
stroyed by  Asphyxia  varies  much,  not  only  in  different  animals,  but  in  different 
states  of  the  same.     Thus,  warm-blooded  animals  are  much  sooner  asphyxiated 
than  Reptiles  or  Invertebrata;   on  the  other  hand,  a  hybernating  Mammal  sup- 
free  in  the  combustion  of  charcoal,  besides  carbonic  acid.     Mr.  Coathupe  (loc.  cit. )  states 
these  to  be  Carbonate,  Muriate,  and  Sulphate  of  Ammonia,  Carbonic   Oxide,  Oxygen, 
Nitrogen,  Watery  vapor,  and  Einpyreumatic  Oil :  to  these  Sulphurous  acid  may  appear  to 
be  properly  added. 

1  The  beneficial  results  of  the  introduction  of  Mercury  by  inhalation  are  strikingly  set 
forth  in  Mr.  Langston  Parker's  Essay  on  "The  Treatment  of  Secondary,  Constitutional, 
and  Confirmed  Syphilis." 


536  OF   RESPIRATION. 

ports  life  for  many  months,  with  a  respiration  sufficiently  low  to  produce  speedy 
asphyxia  if  it  were  in  a  state  of  activity.  And  among  Mammalia  and  Birds, 
there  are  many  species  which  are  adapted,  by  peculiarities  of  conformation,  to 
sustain  a  deprivation  of  air  for  much  more  than  the  average  period.1  Excluding 
these,  it  may  be  stated  as  a  general  fact,  that,  if  a  warm-blooded  animal  in  a 
state  of  activity  be  deprived  of  respiratory  power,  its  muscular  movements  (with 
the  exception  of  the  contraction  of  the  heart)  will  cease  within  five  minutes, 
often  within  three;  and  that  the  circulation  generally  fails  within  ten  minutes. 
Many  persons,  however,  are  capable  of  sustaining  a  deprivation  of  air  for  two, 
three,  or  even  four  minutes,3  without  insensibility  or  any  other  injury;  but  this 
power,  which  seems  possessed  to  the  greatest  degree  by  the  divers  of  Ceylon, 
can  only  be  acquired  by  habit.  The  period  during  which  remedial  means  may 
be  successful  in  restoring  the  activity  of  the  vital  and  animal  functions,  is  not, 
however,  restricted  to  this.  There  is  one  well-authenticated  case,  in  which  re- 
covery took  place  after  a  continuous  submersion  of  fifteen  minutes;3  and  many 
others  are  on  record,  of  the  revival  of  drowned  persons  after  an  interval  of  half 
an  hour,  or  even  more;  but,  there  is  not  the  same  certainty  in  regard  to  these, 
that  the  individuals  may  not  have  occasionally  risen  to  the  surface  and  taken 
breath  there.  It  is  not  improbable,  however,  that  in  some  of  these  cases  a  state 
of  Syncope  had  come  on  at  the  moment  of  immersion,  through  the  influence  of 
fear  or  other  mental  emotion,  concussion  of  the  brain,  &c. ;  so  that,  when  the 
circulation  was  thus  enfeebled,  the  deprivation  of  air  would  not  have  the  same 
injurious  effect,  as  when  this  function  was  in  full  activity.  The  case  would 
then  closely  resemble  that  of  a  hybernating  animal;  for,  in  both  instances,  the 
being  might  be  said  to  live  very  slowly,  and  would  therefore  not  require  the 
usual  amount  of  respiration.  The  condition  of  the  stillborn  infant  is  in  some 
respects  the  same;  and  reanimation  has  been  successfully  attempted,  when 
nearly  half  an  hour  had  intervened  between  birth  and  the  employment  of  re- 
suscitating means,  and  when  probably  a  much  longer  time  had  elapsed  from  the 
period  of  the  suspension  of  the  circulation. 

575.  It  has  now  been  sufficiently  proved,  both  by  experiment  and  by  patho- 

1  Thus,  the  Cetacea  contain  far  more  blood  in  their  vessels,  than  do  any  other  Mam- 
malia ;   and  these  vessels  are  so  arranged,  that  both  arteries  and  veins  are  in  connection 
with  large  reservoirs  or  diverticula.     The  reservoirs  belonging  to  the  former  are  usually 
full ;  but  when  the  Whale  remains  long  under  water,  the  blood  which  they  ccfntain  is  gra- 
dually introduced  into  the  circulation,  and,  after  becoming  venous,  accumulates  in  the 
reservoirs  connected  with  the  venous  system.     By  means  of  this  provision,  the  Whale  can 
remain  under  water  for  more  than  an  hour. 

2  Dr.   Hutchinson  states,  that  any  man  of  ordinary  "vital  capacity,"  can  pass  two 
minutes  without  breathing,  if  he  first  makes  five  or  six  forcible  inspirations  and  expira- 
tions, so  as  to  cleanse  the  lungs  of  the  old  air,  and  then  fills  his  chest  as  completely  as  he 
can.     "  For  the  first  15  seconds  a  giddiness  will  be  experienced;  but  when  this  leaves  us, 
we  do  not  feel  the  slightest  inconvenience  for  want  of  air."     (See  "Cyclop,  of  Anat.  and 
Phys.,"  vol.  iv.  p.  1066.) 

3  The  following  are  the  facts  of  this  case,  as  narrated  by  Marc  (Manuel  d'Autopsie 
Cadaverique  Medico-L6gale,"  p.  165)  on  the  authority  of  Prater. — A  woman  convicted  of 
infanticide  was  condemned  to  die  by  drowning.     This  punishment  was  formerly  inflicted 
in  Germany,  according  to  the  now  obsolete  Caroline  law,  the  culprit  being  inclosed  in  a 
sack  with  a  cock  and  a  cat,  and  sunk  to  the  bottom  of  the  water.     In  this  instance,  the 
woman,  after  having  been  submerged  for  a  quarter  of  an  hour,  was  drawn  up,  and  sponta- 
neously recovered  her  senses.     She  stated  that  she  had  become  insensible  at  the  moment 
of  her  submersion ;   a  circumstance  which  adds  considerable  weight  to  the  supposition, 
based  upon  the  post-mortem,  appearances  in  many  cases  of  drowning,  that  death  often  takes 
place  as  much  by  Syncope  (or  primary  failure  of  the  heart's  action,  consequent  upon  sud- 
den and  violent  emotion,  or  upon  physical  shock)  as  by  Asphyxia.     If  the  reality  of  this 
state  of  Syncopal  Asphyxia  be  admitted,  there  does  not  seem  any  adequate  reason  for 
limiting  the  possible  persistence  of  vitality  in  a  submerged  body,  even  to  half  an  hour ; 
especially  if  the  temperature  of  the  water  be  such  as  not  to  cause  any  rapid  abstraction  of 
its  heat. 


EFFECTS   OF    SUSPENSION   OR   DEFICENCY   OF   RESPIRATION.       537 

logical  observation,  that  the  first  effect  of  the  non-arterialization  of  the  blood  in 
the  lungs,  is  the  retardation  of  the  fluid  in  their  capillaries ;  of  which  the  accu- 
mulation in  the  venous  system,  and  the  deficient  supply  to  the  arterial,  are  the 
necessary  consequences.  It  is  some  time,  however,  before  a  complete  stagnation 
takes  place  from  this  cause ;  since,  as  long  as  the  proportion  of  oxygen  which 
remains  in  the  air  in  the  lungs  is  considerable,  and  that  of  the  carbonic  acid  is 
small,  so  long  will  some  imperfectly  arterialized  blood  find  its  way  back  to  the 
heart,  and  be  transmitted  to  the  system.  This  blood  exerts  a  depressing  influ- 
ence upon  the  nervous  centres,  which  is  aided  by  the  diminution  that  gradually 
takes  place  in  the  quantity  of  blood  propelled  to  them ;  and  thus  the  powers  of  the 
Sensorial  centres  are  suspended,  so  that  the  individual  becomes  unconscious  of 
external  impressions  ;  whilst  the  activity  of  the  Medulla  Oblongata  also  becomes 
diminished,  so  that  the  respiratory  movements  are  enfeebled.  The  progressive 
exhaustion  of  the  oxygen  of  the  air  in  the  lungs  and  the  accumulation  of  carbonic 
acid  in  the  blood,  increase  the  obstruction  in  the  pulmonary  capillaries ;  less 
and  less  blood  is  delivered  to  the  systemic  arteries,  and  what  is  thus  transmitted 
becomes  more  and  more  venous  -,  the  nervous  centres  are  now  completely  pa- 
ralyzed, and  the  respiratory  movements  cease  ;  and  the  deficient  supply  of  blood, 
with  the  depravation  of  its  quality,  act  injuriously  upon  the  muscular  system 
also,  and  especially  weaken  the  contractility  of  the  heart  (§  324).  In  this  en- 
feebled state,  the  final  cessation  of  its  movements  seems  attributable  to  two  dis- 
tinct causes,  acting  on  the  two  sides  respectively ;  for  on  the  right  side  is  the 
result  of  the  over-distension  of  the  walls  of  the  ventricle,  owing  to  the  accumu- 
lation of  venous  blood ;  and  on  the  left  to  deficiency  of  the  stimulus  necessary 
to  excite  the  movement,  which  is  no  longer  sustained  by  its  spontaneous  motil- 
ity  (§  499).  The  heart's  contractility  is  not  finally  lost,  nearly  as  soon  as  its 
movements  cease  ;  for  the  action  of  the  right  ventricle  may  be  renewed,  for  some 
time  after  it  has  ceased,  by  withdrawing  a  portion  of  its  contents — either  through 
the  pulmonary  artery,  their  natural  channel — or,  more  directly,  by  an  opening 
made  in  its  own  parietes,  in  the  auricle,  or  in  the  jugular  vein  (§  504).  On 
the  other  hand,  the  left  ventricle  may  be  again  set  in  action,  by  renewing  its 
appropriate  stimulus  of  arterial  blood.  Hence,  if  the  stoppage  of  the  circula- 
tion have  not  been  of  too  long  continuance,  it  may  be  renewed  by  artificial  re- 
spiration ;  for  the  replacement  of  the  carbonic  acid  by  oxygen  in  the  air-cells 
of  the  lungs,  restores  the  circulation  through  the  pulmonary  capillaries ;  and 
thus  at  the  same  time  relieves  the  distension  of  the  right  ventricle,  and  conveys 
to  the  left  the  due  stimulus  to  its  actions. — Of  the  mode  in  which  the  Pulmo- 
nary circulation  is  thus  stagnated  by  the  want  of  oxygen,  and  renewed  by  its 
ingress  into  the  lungs,  no  other  consistent  explanation  can  be  given,  than  that 
which  is  based  on  the  doctrine  already  laid  ddwn  in  regard  to  the  capillary  circu- 
lation in  general  (§  527) ;  namely,  that  the  performance  of  the  normal  reaction 
between  the  blood  and  the  surrounding  medium  (whether  this  be  air,  water,  or 
solid  organized  tissue)  is  a  condition  necessary  to  the  regular  movement  of  the 
blood  through  the  extreme  vessels.  That  no  mechanical  impediment  to  its 
passage  is  created  (as  some  have  maintained)  by  the  want  of  distension  of  the 
lungs,  has  been  fully  proved  by  the  experiments  of  Dr.  J.  Reid  on  the  induction 
of  Asphyxia  by  the  respiration  of  azote.  And  that  a  contraction  of  the  small 
arteries  and  capillaries,  under  the  stimulus  of  venous  blood,  cannot  be  legiti- 
mately assigned  as  the  cause  of  the  obstruction,  is  evident  from  the  consideration 
brought  to  bear  upon  it  by  the  same  excellent  experimenter  (§  526)  ;  namely, 
the  suddenness  with  which  the  flow  is  renewed  on  the  admission  of  oxygen,  as 
contrasted  with  the  slowness  with  which  arteries  dilate  after  the  removal  of  the 
cause  of  their  contraction.1 

1  For  a  fuller  discussion  of  the  Pathology  of  Asphyxia,  see  the  "  Cyclop,  of  Anat.  and 
Phys.,"  art.  "Asphyxia,"  by  Prof.  Alison;  the  "Library  of  Practical  Medicine,"  vol.  iii. 


538  OP   RESPIRATION. 

576.  It  cannot  be  necessary  here  to  dwell  upon  the  fact,  that  by  the  repeated 
passage  of  the  same  air  through  the  lungs,  it  may,  though  originally  pure  and 
wholesome,  be  so  strongly  impregnated  with  carbonic  acid,  and  may  lose  so 
much  of  its  oxygen,  as  to  become  utterly  unfit  for  the  continued  maintenance 
of  the  aerating  process;  so  that  the  individual  who  continues  to  respire  it, 
shortly  becomes  asphyxiated.     There  are  several  well-known  cases,  in  which  the 
speedy  death  of  a  number  of  persons  confined  together  has  resulted  from  neglect 
of  the  most  ordinary  precautions  for  supplying  them  with  air.     That  of  the 
"  Black  Hole  of  Calcutta,"  which  occurred  in  1756,  has  acquired  an  unenviable 
pre-eminence,  owing  to  the  very  large  proportion  of  the  prisoners,  123  out  of 
146,  who  died  during  one  night's  confinement  in  a  room  18  feet  square,  only 
provided  with  two  small  windows ;  and  it  is  a  remarkable  confirmation  of  the 
views  formerly  stated  (§  210),  and  presently  to  be  again  adverted  to,  that  of 
the  23  who  were  found  alive  in  the  morning,  many  were  subsequently  cut  off 
by  "  putrid  fever."     Such  catastrophes  have  occurred  even  in  this  country,  from 
time  to  time,  though  usually  upon  a  smaller  scale ;  there  has  happened  one  at 
no  distant  date,  however,  which  rivalled  it  in  magnitude.     On  the  night  of  the 
1st  of  December,  1848,  the  deck-passengers  on  board  the  Irish  steamer  London- 
derry were  ordered  below  by  the  Captain,  on  account  of  the  stormy  character 
of  the  weather ;  and  although  they  were  crowded  into  a  cabin  far  too  small  for 
their  accommodation,  the  hatches  were  closed  down  upon  them.    The  consequence 
of  this  was,  that  out  of  150  individuals,  no  fewer  than  70  were  suffocated  before 
the  morning. 

577.  It  cannot  be  too  strongly  impressed   upon    the  Medical  practitioner, 
however,  and  through  him  upon  the  Public  in  general,  that  the  continued  respi- 
ration of  an  atmosphere  charged  in  a  far  inferior  degree  with  the  exhalations 
from  the  Lungs  and  Skin,  is  among  the  most  potent  of  all  the  "predisposing 
causes"  of  disease,  and  especially  of  those  zymotic  diseases  whose  propagation 
seems  to  depend  upon  the  presence  of  fermentable  matter  in  the  blood.     That 
such  is  really  the  fact,  will  appear  from  evidence  to  be  presently  referred  to ; 
and  it  is  not  difficult  to  find  a  complete  and  satisfactory  explanation  of  it.     For, 
as  the  presence  of  even  a  small  percentage  of  carbonic  acid  in  the  respired  air, 
is  sufficient  to  cause  a  serious  diminution  in  the  amount  of  carbonic  acid  thrown 
off  and  of  oxygen  absorbed  (§  561),  it  follows  that  those  oxidating  processes 
which  minister  to  the  elimination  of  effete  matter  from  the  system  must  be 
imperfectly  performed,  and  that  an  accumulation  of  substances  tending  to  putre- 
scence must  take  place  in  the  blood.     Hence  there  will  probably  be  a  considera- 
ble increase  in  the  amount  of  such  matters  in  the  pulmonary  and  cutaneous 
exhalation ;  and  the  unrenewed  air  will  become  charged,  not  only  with  carbonic 
acid,  but  also  with  organic  matter  in  a  state  of  decomposition,  and  will  thus 
favor  the  accumulation  of  both  these  morbific  substances  in  the  blood,  instead 
of  effecting  that  constant  and  complete  removal  of  them,  which  it  is  one  of  the 
chief  ends  of  the  respiratory  process  to  accomplish. — It  has  been  customary  to 
consider  the  consequences  of  imperfect  respiration,  as  exerted  merely  in  pro- 
moting an  accumulation  of  carbonic  acid  in  the  system,  and  in  thus  depressing 
the  vital  powers,  and  rendering  it  prone  to  the  attacks  of  disease.     But  the 
deficiency  of  oxygenation,  and  the  consequent  increase  of  putrescent  matter  in 
the  body,  must  be  admitted  as  at  least  a  concurrent  agency  ;  and  when  it  is  borne 
in  mind  that  the  atmosphere  in  which  a  number  of  persons  have  been  confined 
for  some  time,  becomes  actually  offensive  to  the  smell  in  consequence  of  the 

art.  "  Asphyxia,"  by  the  Author  ;  the  Experimental  Essay  by  Dr.  J.  Reid,  "On  the  Order 
of  Succession  in  which  the  Vital  Actions  are  arrested  in  Asphyxia,"  in  the  "Edinb.  Med. 
and  Surg.  Journ.,"  1841,  and  in  his  "  Anat.,  Physiol.,  and  Pathol.  Researches;"  and  the 
Experimental  Inquiry  by  Mr.  Erichsen,  in  the  "Edinb.  Med.  and  Surg.  Journ.,"  1845. 


EFFECTS   OF    SUSPENSION   OR   DEFICIENCY   OF   RESPIRATION.       539 

accumulation  of  such  exhalations,  and  that  this  accumulation  exerts  precisely 
the  same  influence  upon  the  spread  of  zymotic  disease  (as  will  presently  appear) 
that  is  afforded  by  the  diffusion  of  a  sewer-atmosphere  through  the  respired  air, 
it  scarcely  admits  of  reasonable  doubt  that  the  pernicious  effect  of  over-crowding 
is  exerted  yet  more  through  its  tendency  to  promote  putrescence  in  the  system, 
than  through  the  obstruction  it  creates  to  the  due  elimination  of  carbonic  acid 
from  the  blood.  For  it  is  to  be  remembered,  that  whilst  the  complete  oxidation 
of  the  effete  matters  will  carry  them  off  by  the  lungs  in  the  form  of  carbonic 
acid  and  water,  leaving  urea  and  other  highly-azotized  products  to  pass  off  by 
the  kidneys,  an  imperfect  oxidation  will  only  convert  them  into  those  peculiarly 
offensive  products  which  characterize  the  fecal  excretion  (§  458). * 

578.  Of  the  remarkable  tendency  of  the  Respiration  of  an  atmosphere  charged 
with  the  emanations  of  the  Human  body,  to  favor  the  spread  of  Zymotic  dis- 
eases, a  few  characteristic  examples  will  now  be  given. — All  those  who  have  had 
the  widest  opportunities  of  studying  the  conditions  which  predispose  to  the  in- 
vasion of  Cholera,  are  agreed  that  overcrowding  is  among  the  most  potent  of 
these  ;  and  the  "Report  of  the  General  Board  of  Health/'  on  the  late  epidemic, 
contains  numerous  cases  in  which  this  was  most  evident,  of  which  the  two  fol- 
lowing may  be  selected. — In  the  autumn  of  1849,  a  sudden  and  violent  outbreak 
of  Cholera  occurred  in  the  Workhouse  of  the  town  of  Taunton;  no  case  of 
cholera  having  previously  existed,  and  none  subsequently  presenting  itself, 
among  the  inhabitants  of  the  town  in  general,  though  diarrhoaa  was  prevalent 
to  a  considerable  extent.  The  building  was  altogether  badly  constructed,  and 
the  ventilation  deficient ;  but  this  was  especially  the  case  with  the  school-rooms, 
there  being  only  about  68  cubic  feet  of  air  for  each  girl,  and  even  less  for  the 
boys.  On  Nov.  3,  one  of  the  inmates  was  attacked  with  the  disease;  in  ten 
minutes  from  the  time  of  the  seizure,  the  sufferer  passed  into  a  state  of  hopeless 
collapse;  within  the  space  of  forty-eight  hours  from  the  first  attack,  42  cases 
and  19  deaths  took  place ;  and  in  the  course  of  one  week,  60  of  the  inmates,  or 
nearly  22  per  cent,  of  the  entire  number,  were  carried  off,  whilst  almost  every 
one  of  the  survivors  suffered  more  or  less  severely  from  cholera  or  diarrhoea. 
Among  the  fatal  cases  were  those  of  25  girls  and  9  boys ;  and  the  compara- 
tive immunity  of  the  latter,  notwithstanding  the  yet  more  limited  dimensions 
of  their  school-room,  affords  a  remarkable  confirmation  of  the  general  doctrine 
here  advanced;  for  we  learn  that,  although  "good  and  obedient  in  other  respects, 
they  could  not  be  kept  from  breaking  the  windows/'  so  that  many  of  them  pro- 
bably owed  their  lives  to  the  better  ventilation  thus  established.  Now  in  the 
jail  of  the  same  town,  in  which  every  prisoner  is  allowed  from  819  to  935 
cubic  feet  of  air,  and  this  is  continually  being  renewed  by  an  efficient  system 
of  ventilation,  there  was  not  the  slightest  indication  of  the  epidemic  influence 
(Op.  cit.,  pp.  37  and  71). — The  other  case  to  be  here  cited,  is  that  of  Millbank 
Prison,  in  which  the  good  effects  of  the  diminution  of  previous  overcrowding 
were  extremely  marked.  In  the  month  of  July,  1849,  when  the  epidemic  was 
becoming  general  and  severe  in  the  Metropolis  (especially  in  the  low  ill-drained 
parts  on  both  sides  of  the  river,  in  the  midst  of  which  this  prison  is  situated), 
the  number  of  male  prisoners  was  reduced,  by  the  transfer  of  a  large  propor- 
tion of  them  to  Shorncliff  barracks,  from  1039  to  402;  the  number  of  female 
prisoners,  on  the  other  hand,  not  only  underwent  no  reduction,  but  was  augmented 

1  It  is  a  remarkable  confirmation  of  Prof.  Liebig's  analogy  between  the  imperfect  oxi- 
dation of  eifete  matters  within  the  body,  and  that  combination  in  a  lamp  or  furnace  insuf- 
ficiently supplied  with  air,  which  causes  a  deposit  of  soot  and  various  empyreurnatic  products, 
that  a  set  of  acids  have  been  found  by  Stadeler  in  the  urine  of  the  cow,  bearing  a  remark- 
able analogy  to  well-known  products  of  destructive  distillation,  and  one  of  them  actually 

identical  with  the  carbolic  acid  previously  known  as  one  of  the  ingredients  of  smoke. 

See  Prof.  Gregory's  "Handbook  of  Organic  Chemistry,"  p.  450. 


540  OF   RESPIRATION. 

from  120  to  131.  Now  the  general  mortality  of  London,  which  was  0.9  in 
1000  in  June  and  July,  increased  to  4.5  in  1000  in  August  and  September; 
and  the  mortality  among  the  female  prisoners  underwent  a  similar  increase, 
from  8.3  to  53.4  per  1000;  but  the  mortality  among  the  male  prisoners  exhi- 
bited the  extraordinary  diminution,  from  23.1  per  1000,  which  was  its  rate 
during  June  and  July,  when  the  prison  was  crowded,  to  9.2  per  1000,  which 
was  its  rate  during  August  and  September,  after  the  reduction  had  taken  place 
(Op.  cit.,  App.  B.,  p.  67).  It  is  scarcely  possible  to  imagine  a  more  probative 
case  than  this ;  since  it  shows,  in  the  first  place,  the  marked  influence  of  the 
crowded  state  of  the  prison  upon  the  fatality  of  the  disease — the  diminution  of 
mortality  consequent  upon  the  relief  of  the  overcrowding,  notwithstanding  the 
augmented  potency  of  the  epidemic  influence,  as  indicated  by  the  quintupling 
of  the  general  mortality  of  the  Metropolis — and  the  yet  greater  increase  of 
mortality  among  the  female  prisoners,  which  proved  that  the  diminution  among 
the  males  could  not  be  attributed  to  any  recession  of  the  epidemic  influence  from 
the  locality. 

579.  The  cholera-experience  of  the  Indian  army  is  fertile  in  examples  of  the 
same  kind,  whose  peculiar  character  makes  them  even  more  remarkable.  It  is 
to  be  remembered  that  the  normal  amount  of  Respiration  is  much  lower  in  a 
hot  than  in  a  temperate  climate  (§  564,  a)  ;  consequently,  any  deficiency  of  oxy- 
genation  will  tend  in  a  yet  higher  degree  to  promote  the  accumulation  of  putre- 
scent  matter  in  the  system,  and  this  especially  when  there  has  been  any  unusual 
source  of  "waste,"  such  as  that  induced  by  excessive  muscular  exertion. — The 
circumstances  attendant  upon  the  outbreak  of  Cholera,  in  1846,  at  Kurrachee 
in  Scinde,  in  which  ten  per  cent,  of  an  army  of  6380  men  were  carried  off,  place 
the  influence  of  these  conditions  in  a  very  striking  point  of  view.  In  order  that 
the  comparison  may  be  fairly  made,  the  data  will  be  taken  only  from  European 
regiments,  similar  to  each  other  in  diet,  clothing,  regimen,  habits,  and  every 
other  conceivable  particular,  save  such  as  will  be  mentioned.  Out  of  200 
Officers,  there  were  only  3  deaths  from  Cholera  (only  1  of  these  being  in  an  un- 
complicated case),  or  at  the  rate  of  15  per  1000.  The  2d  Troop  of  Horse  Bri- 
gade, 135  strong,  lost  5  men,  or  at  the  rate  of  37  per  1000.  The  60th  Rifles, 
980  strong,  lost  75  men,  or  at  the  rate  of  76.5  per  1000.  Four  Batteries  of 
Artillery,  375  strong,  lost  37  men,  or  96.6  per  1000.  The  Bombay  Fusiliers, 
764  strong,  lost  83  men,  or  108.6  per  1000.  And  the  86th  Regiment,  1091 
strong,  lost  238  men,  or  218  per  1000.  Among  42  ladies  (wives  and  families 
of  Officers),  there  was  not  a  single  case  of  cholera.  But  among  159  soldiers' 
wives,  there  were  23  deaths,  or  144.6  per  1000.  Now  most  of  the  Officers,  and 
all  the  ladies,  were  quartered  in  well-ventilated  apartments ;  and  the  only  pre- 
disposing cause  from  which  the  former  could  be  considered  as  liable  to  suffer, 
was  the  exposure,  in  common  with  the  soldiers,  to  the  burning  heat  during  the 
hours  of  drill.  Of  the  9  officers  attacked  with  cholera,  4  belonged  to  the  Bombay 
Fusiliers,  and  had  been  living  (like  their  men)  in  tents.  The  Horse  Brigade 
were  lodged  in  good  barracks,  but  had  recently  come  off  a  march  of  1000  miles; 
being  mounted,  however,  they  must  have  suffered  comparatively  little  fatigue 
from  this.  The  60th  Rifles  were  quartered  in  barracks ;  but  the  ventilation  of 
these  was  very  imperfect,  and  the  men  were  much  crowded.  The  battalions  of 
Artillery  were  quartered  in  good  barracks ;  but  three  out  of  the  four  had  re- 
cently made  the  march  of  1000  miles  on  foot.  The  Bombay  Fusiliers  were 
quartered  in  tents,  whose  accommodation  was  so  limited  that  10  or  12  men  were 
cooped  up  in  a  space  14  feet  square,  with  the  thermometer  ranging  from  96°  to 
100°,  without  any  adequate  provision  for  ventilation.  The  86th  Regiment  was 
quartered  in  precisely  the  same  manner ;  and  had  recently  made  the  march  of 
1000  miles  under  very  unfavorable  circumstances,  besides  having  previously 
suffered  from  the  debilitating  influence  of  severe  service.  The  condition  of  the 


EFFECTS    OF   SUSPENSION   OR   DEFICIENCY   OF   RESPIRATION.       541 


soldiers'  wives  as  regards  their  accommodation  would  be  the  same  as  that  of 
their  husbands,  but  they  would  not  be  subjected  to  the  fatigue  and  exposure  of 
drill ;  on  the  other  hand,  their  fatigue  and  exposure  during  a  march  would  be 
scarcely  inferior  to  that  of  the  men ;  and  it  was  among  the  women,  as  among 
the  soldiers,  of  the  86th  Regiment,  that  the  chief  mortality  occurred,  their  loss 
having  been  1  in  6,  or  166.6  per  1000.  Now  if  we  arrange  these  several  divi- 
sions in  a  tabular  form,  we  shall  see  how  very  closely  their  respective  rates  of 
mortality  correspond  with  the  separate  or  concurrent  influence  of  the  different 
factors  here  enumerated. 


Designation. 

Strength. 

Deaths. 

Deaths 
per  1000. 

Exposure  at 
Drill,  &c. 

Provision 
for  Respiration. 

Previous 
exertion. 

Officers'  Ladies  . 

42 

0 

0 

Nil. 

Good 

Nil. 

Officers 

200 

3 

15 

Ordinary 

Mostly  Good 

Nil.  or  slight. 

Horse  Brigade     . 

135 

5 

37 

Ordinary 

Good 

Moderate. 

60th  Rifle 

980 

75 

76.5 

Ordinary 

Bad 

Nil. 

Artillery      . 

375 

37 

96.6 

Ordinary 

Good 

Severe. 

Bombay  Fusiliers 

764 

83 

108.6 

Ordinary 

Very  bad 

Nil. 

Soldiers'  Wives   . 

159 

23 

144.6 

Nil. 

Mostly  very  bad 

Partly  severe. 

Do.  of  86th  Regt. 





166.6 

Nil. 

Very  bad 

Very  severe. 

86th  Regiment.   . 

1091 

238 

218 

Ordinary 

Very  bad 

Very  severe. 

3746 

464 

124 

Thus  we  see  that  the  highest  rate  of  mortality  presents  itself  where  the  three 
causes  were  in  concurrent  action ;  the  absence  of  mortality,  where  neither  of  them 
was  in  operation.  The  difference  between  the  mortality  of  the  Bombay  Fusiliers 
(108.6  per  1000)  and  that  of  the  86th  Regiment  (218  per  1000),  which  were 
under  precisely  the  same  conditions  as  regards  exposure  and  ventilation,  showed 
the  extraordinary  influence  of  previous  exertion ;  but  that  this  would  not  of 
itself  account  for  the  high  rate  of  mortality  in  the  86th,  is  shown  by  the  smaller 
proportion  of  deaths  in  the  Artillery ;  the  influence  of  the  same  march  upon 
three  out  of  its  four  battalions,  having  been  in  a  great  degree  kept  down  by  the 
adequate  provision  for  their  respiration,  so  that  their  mortality  was  less  than 
that  of  the  60th  Rifles,  who  had  not  suffered  from  previous  exertion,  but  were 
overcrowded  in  ill-ventilated  barracks. — It  is  scarcely  possible  to  imagine  any 
more  satisfactory  proof  of  the  preventibility  of  a  large  part  of  this  terrible 
mortality,  than  is  afforded  by  the  analysis  of  this  case  j1  but  if  any  confirmation 
be  required,  it  is  afforded  by  the  case  of  Bellary,  a  fortress  about  250  miles 
north-west  of  Madras.  Although  by  no  means  unhealthily  situated,  this  station 
was  not  free  from  Cholera  for  a  single  year  between  1818  and  1844;  and  violent 
outbreaks  took  place  occasionally,  such  as  that  of  1839,  in  which  the  39th  Regi- 
ment was  reduced  in  five  months  from  735  men  to  645,  the  number  of  deaths 
being  90,  or  122  J  per  1000.  The  barrack-accommodation  in  this  fort  was  ex- 
tremely insufficient ;  and  small  as  it  was,  it  was  occasionally  encroached  upon 
still  further  by  the  introduction  of  troops  upon  their  march,  in  addition  to  the 
regular  garrison.  Every  such  occasion  of  overcrowding  was  shortly  followed 
by  a  large  increase  in  mortality.3  But  since  the  barrack-accommodation  has 
been  improved,  the  troops  quartered  at  Bellary  have  ceased  to  suffer  from  cholera 
in  any  exceptional  degree,  and  the  ordinary  rate  of  mortality  has  been  consider- 
ably diminished. 

580.  The  only  condition  of  atmosphere  which  can  be  compared  with  that 

1  For  a  fuller  statementof  it,  see  the  "  Brit,  and  For.  Med.-Chir.  Rev.,"  vol.  ii.  pp.  81-89. 

2  See  Mr.  Rogers's  "Report  on  Asiatic  Cholera  in  the  Regiments  of  the  Madras  Army 
from  1822  to  1844." 


542  OF    RESPIRATION. 

arising  from  overcrowding,  in  its  effect  upon  the  spread  of  Cholera,  is  that  pro- 
duced by  the  diffusion  of  the  effluvia  of  drains,  sewers,  slaughter-houses,  manure- 
manufactories,  &c.,  which  correspond  closely  in  their  nature  and  effects  with  the 
putrescent  emanations  from  the  living  human  body.  So  remarkably  was  the 
localization  of  the  disease  connected  with  this  condition,  that  the  knowledge  of 
the  existence  of  the  latter  rendered  it  quite  safe  to  predict  the  former,  such  pre- 
dictions being  scarcely  ever  falsified  by  the  result. — As  a  characteristic  illustra- 
tion of  the  operation  of  this  cause,  the  outbreak  of  Cholera  at  Albion  Terrace, 
Wandsworth-road,  may  be  specially  referred  to.  This  place  consisted  of  17 
houses,  having  the  appearance  of  commodious  comfortable  dwellings ;  the  popu- 
lation does  not  seem  to  have  averaged  more  than  7  individuals  per  house,  so  that 
there  was  no  overcrowding ;  yet  out  of  the  total  119  or  120,  no  fewer  than  42 
persons  were  attacked  with  cholera,  of  whom  30  (or  25  percent.)  died.  It  was 
not  difficult  to  account  for  this  fearful  result,  when  the  circumstances  of  the  case 
were  inquired  into.  About  200  yards  in  the  rear  of  the  terrace  was  an  open 
sewer,  whose  effluvia  were  most  offensive  at  the  backs  of  these  houses,  whenever 
the  wind  wafted  them  in  that  direction ;  and  the  drainage  of  the  houses  them- 
selves was  so  bad,  that  a  stench  was  continually  perceived  to  arise  from  differ- 
ent parts  of  the  kitchen  floor,  and  more  especially  from  the  back-kitchen. 
'Moreover,  in  the  house  in  which  the  first  case  of  cholera  occurred,  there  was 
an  enormous  accumulation  of  most  offensive  rubbish,  exhaling  a  putrid  effluvium. 
— And  there  was  also  reason  to  believe  that  the  water  supplied  to  some  of  the 
houses  accidentally  became  contaminated  with  the  contents  of  a  sewer  and  cess- 
pool.1— The  accumulation  of  night-soil  and  other  rubbish  in  a  triangular  space 
of  about  three  acres  in  Witham,  a  suburb  of  Hull,  had  been  represented  to  the 
local  authorities  as  almost  certain  to  induce  a  severe  outbreak  of  cholera  in  the 
neighborhood ;  the  prediction  was  disregarded  ',  but  it  was  most  fearfully  verified 
by  the  occurrence  of  no  fewer  than  91  deaths  in  its  immediate  neighborhood.2 
— Numerous  examples  of  the  same  kind  might  be  cited ;  but  the  following  shows 
the  efficacy  of  preventive  measures.  The  Coldbath-fields  House  of  Correction, 
situated  in  the  neighborhood  of  some  of  the  most  overcrowded  and  ill-drained 
parts  of  the  metropolis,  had  suffered  severely  from  Cholera  in  the  epidemic  of 
1832-3  j  for  out  of  1148  prisioners,  207  were  attacked  with  Cholera,  of  whom 
45  died,  and  319  more  suffered  from  diarrhoea.  At  that  time,  however,  it  was 
discovered  that  the  whole  drainage  of  the  prison  was  in  a  most  defective  state, 
and  steps  were  taken  to  have  it  completely  and  effectually  renewed ;  at  the  same 
time  the  diet  was  somewhat  improved,  and  more  attention  paid  to  temperature 
and  ventilation.  In  the  epidemic  of  1848-9,  with  1100  prisoners,  there  was 
not  a  single  case  of  cholera  in  this  prison,  although  the  disease  was  raging  in 
its  vicinity ;  and  the  cases  of  diarrhoea  were  few  in  number,  and  were  mild  in 
their  character.3 

581.  Now  although  the  Cholera-epidemics  have  been  here  referred  to,  as 
affording  the  most  remarkable  examples  of  the  influence  of  a  contaminated 
atmosphere  in  predisposing  the  individuals  habitually  living  in  it  to  the  invasion 
of  Zymotic  disease,  yet  the  evidence  is  not  less  strong  in  regard  to  the  uniform 
prevalence  of  ordinary  Fevers,  &c.,  in  the  same  localities ;  the  places  in  which 
Cholera  was  the  most  severe  having  been  almost  invariably  known  as  "  fever- 
nests,"  at  other  periods,  and  being  distinguished  by  a  very  high  rate  of  mortality. 
Thus  the  average  age  of  all  persons  who  die  in  Witham  is  only  18  years;  whilst 
the  average  age  at  death  in  the  town  of  Hull  (itself  distinguished  by  an  unusual 
brevity  of  life)  is  23  years. — In  the  "Potteries,"  at  Kensington,  a  locality  in 
which  filth  and  overcrowding  prevail  to  an  almost  unequalled  degree,  the  inor- 

1  "Report  of  the  General  Board  of  Health  on  the  Epidemic  Cholera  of  1848-9,"  p.  43. 

2  Op.  cit.,  p.  45.  3  Op.  cit.,  App.  B,  p.  68. 


EFFECTS   OF    SUSPENSION   OR   DEFICIENCY   OF   RESPIRATION.      543 

tality  for  three  years  previously  to  the  invasion  of  cholera  had  been  such,  that 
the  average  age  at  death  was  only  11  yrs.  7  mos. ;  and  in  the  first  10  months  of 
1849,  out  of  a  population  of  about  1000,  there  were  50  deaths,  of  which  21 
were  from  cholera  and  diarrhoea,  and  29  from  typhus  fever  and  other  diseases. 
It  is  illustrative  of  the  common  points  between  cholera  and  other  zymotic  dis- 
eases, that  the  former  appeared  there  not  only  in  the  same  streets  and  in  the 
same  houses,  but  even  in  the  same  rooms,  which  had  been  again  and  again 
visited  by  typhus ;  and  there  were  several  tenants  of  such  rooms  who  recovered 
from  fever  in  the  spring,  to  fall  victims  to  cholera  in  the  summer.  Subse- 
quently to  this  epidemic,  the  average  age  at  death  has  been  further  reduced,  by 
an  increase  of  infantile  mortality,  to  as  low  as  10  years. — By  way  of  contrast 
it  may  be  stated  that  in  one  of  the  "  Model  Lodging-Houses,"  containing  about 
550  inmates,  among  whom  was  an  unusually  large  proportion  of  children,  the 
rate  of  mortality  during  the  three  years  ending  May,  1851  (including  the  whole 
period  of  the  cholera-epidemic),  was  scarcely  more  than  20  in  1000;  the  propor- 
tion of  deaths  under  ten  years  of  age  was  only  half  that  of  the  metropolis  in 
general ;  there  was  not  a  single  attack  of  cholera,  and  there  were  only  a  few  cases 
of  choleraic  diarrhoea,  although  the  disease  was  raging  in  the  immediate  vicinity  ; 
and  from  the  time  that  the  sewerage  had  beenput[into  complete  order,  typhus  fever 
had  entirely  disappeared,  a  few  cases  having  occurred  soon  after  the  opening  of 
the  buildings,  which  were  distinctly  traceable  to  a  defect  in  the  drainage.3 — The 
following  case  may  be  added,  in  proof  of  the  potency  of  an  atmosphere  charged 
with  putrescent  emanations,  in  rendering  the  system  liable  to  the  attacks  of 
Zymotic  diseases  of  various  kinds.  A  manufactory  of  artificial  manure  formerly 
existed  immediately  opposite  Christchurch  workhouse,  Spitalfields1  which  build- 
ing was  occupied  by  about  400  children,  with  a  few  adult  paupers.  Whenever 
the  works  were  actively  carried  on,  particularly  when  the  wind  blew  in  the 
direction  of  the  house,  there  were  produced  numerous  cases  of  fever,  of  an  in- 
tractable and  typhoid  form  ;  a  typhoid  tendency  was  also  observed  in  measles, 
smallpox,  and  other  infantile  diseases,  and  for  some  time  there  prevailed  a  most 
unmanageable  and  fatal  form  of  aphtha  of  the  mouth,  ending  in  gangrene. 
From  this  last  cause  alone,  12  deaths  took  place  among  the  infants  in  one  quar- 
ter. In  the  month  of  December,  1848,  when  cholera  had  already  occurred  in 
the  neighborhood,  60  of  the  children  in  the  workhouse  were  suddenly  seized 
with  violent  diarrhoea  in  the  early  morning.  The  proprietor  was  compelled  to 
close  his  establishment,  and  the  children  returned  to  their  ordinary  health. 
Five  months  afterwards,  the  works  were  recommenced ;  in  a  day  or  two  subse- 
quently, the  wind  blowing  from  the  manufactory,  a  most  powerful  stench  per- 
vaded the  building.  In  the  night  following,  45  of  the  boys,  whose  dormitories 
directly  faced  the  manufactory,  were  again  suddenly  seized  with  severe  diarrhoea ; 
whilst  the  girls,  whose  dormitories  were  in  a  more  distant  part,  and  faced  in 
another  direction,  escaped.  The  manufactory  having  been  again  suppressed, 
there  was  no  subsequent  return  of  diarrhoea.2 

582.  It  may  not  be  amiss  to  add  a  few  examples  drawn  from  the  experience 
which  our  Indian  possessions  have  afforded,  of  the  influence  of  an  insufficient 
supply  of  pure  air  upon  the  ordinary  mortality  in  our  army  and  among  the 
people  under  our  control. — There  are  various  military  stations  which  have  lain 
under  a  most  ill-deserved  repute  for  unhealthiness,  in  consequence  of  the  very 
imperfect  barrack-accommodation  afforded  to  the  troops  quartered  in  them. 
Thus  at  Secunderabad,  in  the  Madras  command,  the  average  annual  mortality 
for  the  fifteen  years  previous  to  1846— 7  was  75  per  1000;  this  being  nearly 

'  "Report  on  Cholera,"  App.  B,  pp.  48  and  77  ;  and  Mr.  Grainger's  subsequent  "  Re- 
port on  the  present  state  of  certain  parts  of  the  Metropolis,  and  on  the  Model  Lodgino- 
Houses  of  London,"  pp.  29,  36. 

2  "Report  on  Cholera,"  p.  42. 


544  OF   RESPIRATION. 

double  the  average  of  the  whole  presidency,  and  more  than  double  that  of  the 
remainder  of  the  stations.  Now  the  complaints  made  year  after  year,  by  the 
medical  officers  of  the  troops  which  have  been  successively  quartered  at  this 
station,  leave  no  room  for  doubt  as  to  the  chief  cause  of  this  excess ;  for  the 
regiments  of  the  line  quartered  at  Secunderabad  have  been  always  crowded  in 
barracks  quite  insufficient  for  their  accommodation,  one-third  of  the  men  having 
been  obliged  to  sleep  in  the  verandahs,  and  the  remainder  getting  by  no  means 
a  due  allowance  of  fresh  air;  whilst,  on  the  other  hand,  the  officers  of  these 
very  regiments,  who  are  better  accommodated,  and  the  detachment  of  artillery 
quartered  in  more  roomy  barracks,  at  no  great  distance,  have  never  participated 
in  this  unusual  mortality,  thereby  clearly  showing  the  absence  of  any  special 
causes  of  disease  at  this  station,  which  might  not  be  easily  removed.1 — The 
Barrackpore  station,  in  the  Bengal  command,  is  even  worse  than  the  foregoing, 
for  every  regiment  quartered  there  seems  to  suffer  an  almost  complete  decimation 
annually.  Yet  there  is  ample  evidence  that  here  also  the  chief  fault  lies  in  the 
barrack  accommodation. — But  one  of  the  most  terrible  instances  of  the  continu- 
ance of  a  high  rate  of  mortality,  which  is  almost  entirely  attributable  to  an  in- 
sufficient supply  of  air,  is  that  which  is  furnished  by  the  jails  under  British 
control  in  India.  In  these  are  usually  confined  no  fewer  than  40,000  prisoners, 
chiefly  natives ;  and  the  average  annual  mortality  of  the  whole  was  recently  10 
per  cent.,  rising  in  some  cases  to  26  per  cent.,  or  more  than  one  in  four.  This 
is  easily  accounted  for,  when  it  is  known  that  in  no  case  is  there  an  allowance 
of  more  than  300  cubic  feet  of  air-space  for  each  individual,  whilst  in  some 
instances  70  cubic  feet  is  the  miserable  average  !3 

583.  One  more  set  of  cases  will  be  cited,  as  showing  the  marked  effect  of  the 
habitual  respiration  of  a  contaminated  atmosphere,  not  merely  in  engendering 
a  liability  to  zymotic  disease,  but  in  directly  producing  a  special  form  of  infan- 
tile disease,  of  the  most  fearful  nature. — The  dwellings  of  the  great  bulk  of  the 
population  of  Iceland  seem  as  if  constructed  for  the  express  purpose  of  poison- 
ing the  air  which  they  contain.  They  are  small  and  low,  without  any  direct 
provision  for  ventilation,  the  door  serving  alike  as  window  and  chimney ;  the 
walls  and  roof  let  in  the  rain,  which  the  floor,  chiefly  composed  of  hardened 
sheep-dung,  sucks  up ;  the  same  room  generally  serves  for  all  the  uses  of  the 
whole  family,  and  not  only  for  the  human  part  of  it,  but  frequently  also  for  the 
sheep,  which  are  thus  housed  during  the  severer  part  of  the  winter.  The  fuel 
employed  in  the  country  districts  chiefly  consists  of  cow-dung  and  sheep-dung, 
caked  and  dried;  and  near  the  sea-coast,  of  the  bones  and  refuse  of  fish  and 
sea-fowl ;  producing  a  stench,  which,  to  those  unaccustomed  to  it,  is  completely 
insupportable.  In  addition  to  this,  it  may  be  mentioned  that  the  people  are 
noted  for  their  extreme  want  of  personal  cleanliness;  the  same  garments  (chiefly  of 
black  flannel)  being  worn  for  months  without  being  even  taken  off  at  night.  Such 
an  assemblage  of  unfavorable  conditions,  combined  with  the  cold  damp  nature 
of  the  climate,  might  have  been  expected  to  induc^  tubercular  diseases  of  various 
kinds ;  but  from  these  the  Icelanders  appear  to  enjoy  a  special  exemption  (§  404, 

1  It  is  a  remarkable  confirmation  of  the  view  formerly  stated  (g  411),  as  to  the  tendency 
of  the  habitual  use  of  Alcoholic  liquors  to  induce  a  "  fermentible"  condition  of  the  blood, 
by  obstructing  the  elimination  of  effete  matters  by  the  respiratory  process  ($  5G4,  i),  that 
when  the  84th  Regt.,  which  is  distinguished  for  its  sobriety,  was  quartered  at  Secunderabad 
in  1847-8,  it  lost  only  39  men  out  of  1139,  or  34.2  per  1000,  the  average  mortality  of  the 
other  stations  in  the  Presidency  being  about  the  same  as  usual.     On  the  other  hand,  the 
63d  Regt.,  which  was  far  from  deserving  a  reputation  for  temperance,  had  lost  73  men 
during  the  first  nine  months  of  the  preceding  year,  or  at  the  rate  of  78.8  per  1000  during 
the  entire  year. — All  the  facts  here  stated  in  regard  to  Secunderabad,  have  been  obtained 
by  the  Author  direct  from  the  Army  Medical  Returns. 

2  Dr.  Mackinnon's   "Treatise  on  the  Public  Health,  &c.,  of  Bengal,"  Cawnpore,  1848, 
Chap.  1. 


EFFECTS    OF    SUSPENSION    OR   DEFICIENCY    OF   RESPIRATION.       545 

in.).  Syphilis,  also,  is  wanting,  or  nearly  so ;  and  yet,  notwithstanding  that 
the  number  of  births  is  fully  equal  to  the  usual  average,  the  population  is  sta- 
tionary, and  in  some  parts  actually  diminishing.  This  is  partly  due  to  the 
extent  and  fatality  of  the  epidemic  diseases,  of  which  some  one  or  other  spreads 
through  the  island  nearly  every  year ;  but  it  is  chiefly  owing  to  the  extraordi- 
nary mortality  of  infants  from  Trismus  nascentium,  which  carries  off  a  large 
proportion  of  them  between  the  fifth  and  the  twelfth  days  after  their  birth.  It 
is  in  the  little  island  of  Westmannoe  and  the  opposite  parts  of  the  coast  of  Ice- 
land, where  the  bird-fuel  is  used  all  the  year  round,  instead  of  (as  elsewhere) 
during  a  few  months  only,  that  this  disease  is  most  fatal ;  the  average  mortality, 
for  the  last  twenty  years,  during  the  first  twelve  days  of  infantile  life,  being  no 
less  than  64  per  cent.,  or  nearly  two  out  of  three.* — Now  it  is  not  a  little  remark- 
able that  the  very  same  disease  should  have  prevailed,  under  conditions  almost 
identically  the  same,  in  the  island  of  St.  Kilda,  one  of  the  Western  Hebrides ; 
the  state  of  which  was  made  known  by  Mr.  Maclean,  who  visited  it  in  1838. 
The  population  of  this  island,  too,  was  diminishing  rather  than  increasing,  in 
consequence  of  the  enormous  infantile  mortality  '}  four  out  of  every  Jive  dying, 
from  Trismus  nascentium,  between  the  eighth  and  twelfth  days  of  their  exist- 
ence. The  great  if  not  the  only  cause  of  this  mortality,  was  the  contamination 
of  the  atmosphere  by  the  filth  amidst  which  the  people  lived.  Their  huts,  like 
those  of  the  Icelanders,  were  small,  low-roofed,  and  without  windows ;  and 
were  used  during  the  winter  as  stores  for  the  collection  of  manure,  which  was 
carefully  laid  out  upon  the  floor,  and  trodden  under  foot  to  the  depth  of  several 
feet.  On  the  other  hand,  the  clergyman,  who  lived  exactly  as  did  those  around 
him,  except  as  to  the  condition  of  his  house,  and  brought  up  a  family  of  four 
children  in  perfect  health ;  whereas,  according  to  the  average  mortality  around 
him,  at  least  three  out  of  the  four  would  have  been  dead  within  the  first  fort- 
night.— Of  the  degree  in  which  this  fearful  disease  is  dependent  upon  impurity 
of  the  atmosphere,  and  is  preventible  by  adequate  ventilation,  abundant  proof 
is  afforded  by  the  experience  of  Hospitals  and  Workhouses  in  our  own  country. 
Thus  in  the  Dublin  Lying-in  Hospital,  up  to  the  year  1782,  the  mortality  with- 
in the  first  fortnight,  almost  entirely  from  Trismus  nascentium,  was  1  in  every 
6  children  born.  The  adoption,  under  the  direction  of  Dr.  Joseph  Clarke,  of 
an  improved  system  of  ventilation,  reduced  the  proportion  of  deaths  from  this 
cause  to  1  in  19  £.  And  further  improvements  in  ventilation,  with  increased 
attention  to  cleanliness,  during  the  seven  years  in  which  Dr.  Collins  was  Master 
of  this  Institution,  reduced  the  number  of  deaths  from  this  disease  to  no  more 
than  three  or  four  yearly.3 — A  similar  amelioration  took  place  about  a  century 
ago,  in  the  condition  of  the  London  Workhouses,  in  which  23  out  of  24  infants 
had  previously  died  within  the  first  year,  and  a  large  proportion  of  these  within 
the  first  month ;  for  owing  to  a  parliamentary  inquiry  which  was  called  forth 
by  this  fearful  state  of  things,  the  proportion  of  deaths  was  speedily  reduced 
(chiefly  by  improvement  in  ventilation)  from  2600  to  450  annually. 

584.  Thus  it  appears  that  in  all  climates,  and  under  all  conditions  of  life,  the 
purity  of  the  atmosphere  habitually  respired  is  essential  to  the  maintenance  of 
that  power  of  resisting  disease,  which,  even  more  than  the  habitual  state  of 
health,  is  a  measure  of  the  real  vigor  of  the  system.  For,  owing  to  the  extra- 
ordinary capability  which  the  human  body  possesses  of  accommodating  itself  to 
circumstances,  it  not  unfrequently  happens  that  individuals  continue  for  years 
to  breathe  a  most  unwholesome  atmosphere,  without  apparently  suffering  from  it ; 
and  thus,  when  they  at  last  succumb  to  some  Epidemic  disease,  their  death  is 
t 

1  See  "Island  undersogt  fra  kegevidenskabeligt  Synspunct."     Af  P.  A.  Sclileisner,  M. 
D.— Copenhagen,  1849. 

2  See  Dr.  Collins's  "Practical  Treatise  on  Midwifery,"  p.  513. 

35 


546  OF   NUTRITION. 

attributed  solely  to  the  latter ;  the  previous  preparation  of  their  bodies  for  the 
reception  and  development  of  the  zymotic  poison,  being  altogether  overlooked. 
It  is  impossible,  however,  for  any  one  who  carefully  examines  the  evidence,  to 
hesitate  for  a  moment  in  the  conclusion,  that  the  fatality  of  epidemics  is  almost 
invariably  in  precise  proportion  to  the  degree  in  which  an  impure  atmosphere 
has  been  habitually  respired  ;  that  an  atmosphere  loaded  with  putrescent  mias- 
mata may  afford  a  nidus  wherein  a  zymotic  poison  undergoes  a  marked  increase 
in  quantity  and  intensity,  the  putrescent  exhalations  from  the  lungs  and  skin 
of  the  living  subject  being  at  least  as  effectual  in  furnishing  such  a  "  nidus,"  as 
are  the  emanations  from  fecal  discharges  or  from  other  decomposing  matters ; 
that  the  habitual  respiration  of  such  an  atmosphere  tends  to  induce  a  condition 
of  the  blood,  which  renders  it  peculiarly  susceptible  of  perversion  by  the  intro- 
duction of  zymotic  poisons,  and  which  favors  their  multiplication  within  the 
system  j1  and  lastly,  that  by  due  attention  to  the  various  means  of  promoting 
atmospheric  purity,  and  especially  to  efficient  ventilation  and  sewerage,  the  rate 
of  mortality  may  be  enormously  decreased,  the  amount  and  severity  of  sickness 
lowered  in  at  least  an  equal  proportion,  and  the  fatality  of  epidemics  almost 
completely  annihilated.  And  it  cannot  be  too  strongly  borne  in  mind,  that 
the  efficacy  of  such  preventive  measures  has  been  most  fully  substantiated,  in 
regard  to  many  of  the  very  diseases  in  which  the  curative  power  of  Medical 
treatment  has  seemed  most  doubtful ;  as,  for  example,  in  Cholera  and  Malignant 
Fevers. 


CHAPTER    XI. 

OF   NUTRITION. 

1. —  General  Considerations. — Formative  Power  of  Individual  Parts. 

585.  THE  function  of  Nutrition,  considered  in  the  widest  acceptation  of  the 
term,  includes  the  whole  series  of  operations,  by  which  the  alimentary  materials 
—prepared  by  the  Digestive  process,  introduced  into  the  system  by  Absorption, 
and  carried  into  its  penetralia  by  the  Circulation — are  converted  into  Organized 
tissue  ;  but  in  a  more  limited  sense  it  may  be  understood  as  referring  to  the  last 
of  these  operations  only,  that  of  Histogenesis  or  tissue-formation,  to  which  all 
the  other  organic  functions,  in  so  far  as  they  are  concerned  in  maintaining  the 
life  of  the  individual,  are  subservient,  by  preparing  and  keeping  in  the  requisite 
state  of  purity  the  materials  at  the  expense  of  which  it  takes  place.  It  has  been 
shown  in  the  earlier  portion  of  this  volume,  that  every  integral  part  of  the  living 
body  possesses  a  certain  capacity  for  growth  and  development,  in  virtue  of  which 
it  passes  through  a  series  of  successive  phases,  under  the  influence  of  the  steady 
heat,  which  in  the  warm-blooded  animal  is  constantly  acting  upon  it  (CHAP,  in., 
SECT.  1,  2) ;  this  capacity  being  an  endowment  which  it  derives  by  direct  descent 

1  A  careful  consideration  of  the  very  satisfactory  evidence  which  has  been  of  late  yeai\s 
collected  on  this  point,  must  (in  the  Author's  opinion)  satisfy  any  competent  and  unprejudiced 
inquirer,  that  Endemic  Fevers,  originating  in  local  causes  (marsh  miasmata  and  the  like), 
and  affecting  those  only  who  are  exposed  to  such  causes,  may  find,  by  the  crowding  together 
of  infected  subjects,  a  nidus  for  development  within  the  Human  system ;  so  that  these  dis- 
eases then  become  communicable  by  human  intercourse,  although  not  so  originally. — For 
a  discussion  of  this  subject,  see  the  Articles  on  "Yellow  fever"  in  the  "Brit,  and  For. 
Med.-Chir.  Rev.,"  vols.  i.  and  iv. 


FORMATIVE   POWER   OF   INDIVIDUAL   PARTS.  547 

from  the  original  germ,  but  undergoing  a  gradual  diminution  with  the  advance 
of  life,  until  the  power  of  maintenance  is  no  longer  adequate  to  antagonize  the 
forces  that  tend  to  the  disintegration  of  the  system  (CHAP.  HI.,  SECT.  3).  It 
has  been  also  shown  that,  notwithstanding  the  diversities  in  the  structure  and 
composition  of  the  several  tissues,  the  Blood  supplies  the  materials  which  each 
requires ;  every  tissue  possessing  (so  to  speak)  an  elective  affinity  for  some  par- 
ticular constituents  of  that  fluid,  in  virtue  of  which  it  abstracts  them  from  it 
and  appropriates  them  to  its  own  uses. — But  it  has  been  shown,  on  the  other 
hand,  that  the  "  formative  capacity"  does  not  exist  in  the  tissues  alone,  but  is 
shared  by  the  Blood,  which  must  itself  be  regarded  as  deriving  it  from  the 
original  germ  ;  for  there  are  certain  simple  kinds  of  tissue,  which  seem  to  take 
their  origin  directly  in  its  plastic  components  (§§  26-29).  Of  others  which 
cannot  be  said  thus  to  originate  in  the  blood,  the  development  is  entirely  deter- 
mined by  the  quantity  of  their  special  pabula  which  it  may  contain  (§  120). 
And  even  of  those  tissues  which  must  be  considered  as  most  independent  and 
self-sustaining,  the  development  is  not  only  checked  by  the  want  of  a  due  supply 
of  their  appropriate  materials,  but  it  is  modified  in  a  very  remarkable  degree  by 
the  presence  of  abnormal  substances  in  the  blood,  which  single  out  particular 
parts,  and  effect  determinate  alterations  in  their  nutrition,  in  such  a  constant 
manner  as  to  show  the  existence  of  a  peculiar  "elective  affinity"  between  them 
(§  201). — In  so  far,  then,  as  the  process  of  Nutrition  is  dependent  upon  the  due 
supply  and  normal  state  of  the  Blood,  its  conditions  have  been  already  suffi- 
ciently discussed ;  and  we  have  now  only  to  consider  it  in  its  relations  to  the 
Tissues. 

586.  The  demand  for  Nutrition  primarily  arises  from  the  tendency  of  the  or- 
ganism to  simple  increase  or  growth.     Of  this  we  have  the  most  characteristic 
illustration  in  the  multiplication  of  the  first  embryonic  cell,  by  the  simple  pro- 
cess of  "duplicative  subdivision,"  (§  104;)  whereby  a  multitude  of  cells  is  pro- 
duced, every  one  of  which  is  similar  in  all  essential  particulars  to  the  original. 
But  after  the  different  parts  of  this  homogeneous  embryonic  mass  have  taken 
upon  themselves  their  respective  modes  of  development,  so  as  to  generate  a 
diversity  of  tissues  and  organs,  each  one  of  these  continues  to  increase  after  its 
own  plan ;  and  thus  the  child  becomes  the  adult,  with  comparatively  little  change 
but  that  of  growth.     An  excess  of  growth,  taking  place  conformably  to  the 
normal  plan  of  the  tissue  or  organ,  constitutes  Hypertrophy  ;  whilst  a  diminu- 
tion, without  degeneration  or  alteration  of  structure,  is  that  which  is  properly 
distinguished  as  Atrophy. — But  Growth  is  not  confined  to  the  period  of  increase 
of  the  body  generally ;  for  it  may  manifest  itself  in  particular  organs  or  tissues, 
as  a  normal  operation,  at  any  subsequent  part  of  life.     Thus  when  there  is  an 
extraordinary  demand  for  the  functional  activity  of  a  particular  set  of  Muscles, 
it  is  supplied  by  an  increase  in  the  amount  of  their  contractile  tissue  (§  312) ;  . 
or  if  one  of  the  Kidneys  be  disabled  from  performing  its  office,  the  other  may  be 
rendered  capable  of  fulfilling  it,  by  an  agumented  production  of  its  own  secretory 
tissue ;  or  if  there  be  an  excess  of  fatty  matters  in  the  blood,  they  may  be  elimi- 
nated by  an  augmentation  of  the  Adipose  tissue  throughout  the  body. — And 
further,  even  where  there  is  no  such  manifestation  of  increase,  there  is  really  a 
continual  growth  in  all  the  tissues  actively  concerned  in  the  vital  operations,  and 
this  even  to  the  very  end  of  life ;  although  it  may  be  so  far  counterbalanced,  or 
even  surpassed,  by  changes  of  an  opposite  kind,  that,  instead  of  augmentation  in 
bulk,  there  is  absolute  diminution. 

587.  The  evolution  of  the  complete  organism  from  its'germ,  however,  does  not 
consist  in  mere  growth ;  for  by  such  a  process  nothing  would  be  produced  but 
an  enormous  aggregation  of  simple  cells,  possessing  little  or  no  mutual  depend- 
ence, like  those  which  constitute  the  shapeless  masses  of  the  lowest  Algae.     In 
addition  to  increase,  there  must  be  development ',  that  is,  a  passage  to  a  higher 


548  OF   NUTRITION. 

condition,  both  of  form  and  structure,  so  that  the  part  in  which  this  change 
takes  place  becomes  fitted  for  some  special  function,  and  is  advanced  towards 
the  state  in  which  it  exists  in  the  highest  or  most  completed  form  of  its  specific 
type.  Thus  the  development  of  tissue  consists  in  the  change  from  a  simple  mass 
of  cells  or  fibres  into  any  other  form ;  as  in  the  production  of  dentine  from  the 
cellular  substance  of  the  tooth-pulp  (§  279),  or  in  the  formation  of  bone 
in  the  sub-periosteal  membrane  (§  267).  So,  again,  the  developmental 
change  is  seen  in  the  passage  of  an  entire  organ  from  a  lower  to  a  higher  con- 
dition, by  the  evolution  of  new  parts,  or  by  a  change  in  the  relations  of  those 
already  existing,  even  though  the  change  in  its  texture  should  consist  of  little 
else  than  of  simple  increase;  thus,  in  the  development  of  the  heart,  we  have  the 
original  single  cavity  subdivided,  first  into  two  and  at  last  into  four  chambers ; 
and  in  the  development  of  the  brain  we  find  the  sensory  ganglia  to  be  the  parts 
first  formed,  the  anterior  lobes  of  the  cerebrum  to  be  evolved  (as  it  were)  from 
these,  the  middle  lobes  sprouting  forth  from  the  back  of  the  anterior,  and 
the  posterior  from  the  back  of  the  middle;  yet,  with  all  this,  there  is  no 
production  of  any  new  kind  of  tissue,  the  new  parts  being  generated  at 
the  expense  of  histological  components  identical  with  those  of  the  pre-ex- 
isting. Now  it  is  in  the  early  period  of  embryonic  life,  that  the  develop- 
mental process  is  most  remarkably  displayed ;  for  it  is  then  that  we  see  that  trans- 
formation of  the  primordial  cells  into  tissues  of  various  kinds,  which  originates 
a  special  nisus  in  each  part,  whereby  the  production  of  the  same  tissue  in  con- 
tinuity with  that  first  formed,  comes  to  be  a  simple  act  of  growth ;  and  it  is  then 
also  that  we  observe  that  marking  out  of  all  the  principal  organs,  by  the  de- 
velopment of  tissue  in  particular  directions,  which  makes  all  subsequent  evolu- 
tion but  a  completion  or  filling  up  of  the  plan  thus  sketched  out.  Thus  during 
the  first  few  days  of  incubation  in  the  Chick,  the  foundation  is  laid  of  the  verte- 
bral column,  the  nervous  centres,  the  organs  of  sense,  the  heart  and  circulating 
system,  the  alimentary  canal,  the  respiratory  apparatus,  the  liver,  the  kidneys, 
and  of  many  other  parts;  and  at  the  termination  of  that  period  the  chick  emerges 
in  such  a  state  of  completeness  of  development,  that  little  else  than  increase 
is  wanting,  save  in  the  plumage  and  sexual  organs,  to  raise  it  to  its  perfect  type. 
The  same  may  be  said  of  the  Human  organism ;  save  that  the  period  of  its 
development  is  relatively  longer,  in  accordance  with  the  higher  grade  which  it 
is  ultimately  to  attain ;  its  earliest  stages  being  passed  through,  however,  with 
extraordinary  rapidity.  The  completer  evolution  of  the  generative  organs,  of  the 
osseous  skeleton,  and  of  the  teeth,  constitute  the  principal  developmental  changes 
which  the  Human  organism  undergoes  in  its  progress  from  the  infantile  to  the 
adult  condition ;  almost  every  other  alteration  consisting  in  simple  increase  of 
its  several  component  tissues  and  organs,  without  any  essential  change  in  their 
form  or  structure.  Aad  when  the  adult  type  has  been  once  completely  at- 
tained, every  subsequent  change  is  one  rather  of  degeneration  than  of  develop- 
ment, of  retrogression  rather  than  of  advance. 

588.  The  difference  between  the  two  processes  of  Growth  and  Development 
is  most  characteristically  shown  in  those  cases  in  which  there  is  a  partial  or 
complete  arrest  of  one  of  them  without  any  corresponding  impairment  of  the 
other.  Thus  a  dwarf,  however  small  in  stature,  may  present  a  perfect  develop- 
ment of  every  part  that  is  characteristic  of  the  complete  human  organism  ;  the 
deficiency  being  solely  in  the  capacity  for  growth.  On  the  other  hand,  the  usual 
size  at  birth  may  be  attained,  and  every  organ  may  present  its  ordinary  dimen- 
sions, and  yet  some  important  part  may  be  found  in  a  condition  of  arrested 
development ;  thus  the  heart  may  consist  of  but  a  single  cavity,  or  the  inter- 
ventricular  or  interauricular  septa  may  be  incomplete,  so  that  it  has  not  passed 
beyond  the  grade  of  development  which  it  had  attained  at  an  early  period  of 
embryonic  life,  although  its  growth  may  have  continued ;  or  the  brain  may  in 


FORMATIVE   POWER   OF   INDIVIDUAL   PARTS.  549 

like  manner  exhibit  a  deficiency  of  the  posterior  lobes,  or  of  the  corpus  callosum, 
or  of  some  other  part  whose  formation  normally  takes  place  in  the  latter  months 
of  intra-uterine  life,  although  the  parts  already  produced  may  have  continued 
to  grow  at  their  usual  rate. — Numerous  instances  of  the  same  kind  might  be 
cited,  but  these  must  suffice. 

589.  The  demand  for  Nutrition  arises,  however,  not  merely  from  the  exercise 
of  the  formative  powers  which  are  concerned  in  the  building  up  of  the  organism, 
but  also  from  the  degeneration  and  decay  which  are  continually  taking  place  in 
almost  every  part  of  it,  and  the  effects  of  which,  if  not  antagonized,  would 
speedily  show  themselves  in  its  complete  disintegration.  We  have  seen  (§  114) 
that  as  each  component  cell  of  the  organism  has  to  a  certain  degree  an  inde- 
pendent life  of  its  own,  so  has  it  also  a  limited  duration ;  and  that  its  duration 
usually  bears  an  inverse  ratio  to  its  functional  activity.  This  is  particularly 
striking,  when  we  compare  the  ratio  of  change  in  the  organism  of  cold-blooded 
animals  at  low  and  at  high  temperatures  ;  for  they  live  slowly,  need  little  nutri- 
ment, give  off  but  a  small  amount  of  excretory  products,  and  require  a  long 
time  for  the  performance  of  the  reparative  processes,  under  the  former  condi- 
tion ;  but  live  fast,  require  a  comparatively  large  supply  of  nutriment,  give  off 
a  far  greater  amount  of  carbonic  acid  and  other  compounds  resulting  from  the 
"  waste"  of  tissue,  and  exhibit  a  far  more  rapid  reparation  of  injuries,  in  the 
latter  state.  The  constantly  high  temperature  of  Man,  as  of  other  warm-blooded 
animals,  prevents  this  difference  from  being  displayed  in  him  in  a  similar  man- 
ner ;  but  it  is  well  seen  when  we  contrast'  his  different  tissues  with  each  other, 
and  study  their  respective  histories.  For  whilst  there  are  some  which  appear 
to  pass  through  all  their  stages  of  growth,  maturation,  and  decline,  within  a 
limited  period,  there  are  others  whose  existence  seems  capable  of  almost  inde- 
finite prolongation,  and  others,  again,  which  are  liable  to  have  a  period  put  to  it 
at  any  time,  by  the  direction  of  their  vital  force  into  other  channels. — Of  those 
belonging  to  the  first  category,  a  characteristic  example  is  presented  by  the  ovule ; 
which  if  not  fertilized  within  a  limited  period  after  its  maturation,  speedily 
declines  and  decays;  and  the  same  law  of  limited  duration  doubtless  extends  to 
a  large  proportion  of  such  tissues  as  are  actively  concerned  in  the  maintenance 
of  the  organic  functions ;  as,  for  example,  the  corpuscles  of  the  blood  (§  148), 
the  epithelial  cells  of  mucous  membranes,  which  minister  to  absorption  in  one 
situation  (§  461)  and  to  secretion  in  another  (§  235),  the  cells  forming  the  paren- 
chyma of  the  ductless  glands  (§482,iv.),and  many  others. — The  contrary  extreme 
to  this  may  be  found  in  those  tissues  whose  functions  are  rather  physical  than  vital; 
and  especially  in  such  as  undergo  consolidation  by  the  deposit  of  solidifying  matter, 
either  in  combination  with  the  animal  membrane  or  fibre,  or  in  its  interstices. 
Such  tissues  are  withdrawn  from  the  general  current  of  vital  action,  and  there 
seems  to  be  no  definite  limit  to  their  duration,  except  such  as  is  imposed  by  the 
chemical  and  mechanical  degradation  to  which  they  are  subjected.  This  appears 
to  be  the  case  with  the  simple  fibrous  tissues,  especially  the  yellow,  even  in 
their  soft  or  unconsolidated  state;  but  it  is  far  more  obvious  in  the  osseous  sub- 
stance, which  is  chiefly  formed  by  the  combination  of  calcareous  salts  with  the 
fibrous  animal  basis.  So,  again,  in  the  dentine  and  enamel  of  teeth,  we  have 
examples  of  tissues  that  have  once  undergone  a  similar  consolidation,  retaining 
their  condition  unchanged  through  the  whole  remainder  of  life,  under  circum- 
stances which  show  that,  if  any  nutritive  change  take  place  in  them,  its  amount 
must  be  extremely  small.  Yet  it  is  curious  to  observe  that,  both  in  the  osseous 
and  dentinal  structures  of  the  young,  there  is  obviously  a  determinate  limit  of 
existence ;  as  is  shown  in  the  rapid  disappearance  of  a  considerable  part  of  the 
lamellse  first  formed  in  the  cartilaginous  matrix  (§  265),  as  also  in  the  death 
and  removal  which  continue  to  take  place  in  the  inner  and  older  portions  of  the 
shaft  of  a  round  bone  during  the  whole  period  of  its  increase  (§  267);  and  in 


550  OF    NUTRITION. 

the  exuviation,  at  a  certain  definite  epoch,  of  the  first  set  of  teeth,  which  exu- 
viation is  usually  preceded  by  the  death  and  disintegration  of  their  own  texture 
(§  289).  In  hair,  nails,  and  other  epidermic  appendages,  which,  when  once  their 
component  cells  have  undergone  consolidation  by  the  deposit  of  horny  matter 
in  their  interior,  may  remain  unchanged  for  centuries,  we  must  recognize  the 
same  principle  of  indefinite  duration,  in  connection  with  the  annihilation  of  vital 
activity;  the  chemical  constitution  of  these  substances,  moreover,  being  such 
as  renders  them  but  little  prone  to  be  acted  upon  by  ordinary  decomposing 
agencies. — In  the  case  of  the  Muscular  and  Nervous  tissues,  however,  we  trace 
the  operation  of  causes  that  differ  from  any  of  those  already  specified.  These 
tissues  are  doubtless  subject,  like  all  others  that  are  distinguished  by  their  vital 
activity,  to  the  law  of  limited  duration ;  for  we  find  that,  when  not  called  into 
use,  they  undergo  a  gradual  disintegration  or  wasting,  which  is  not  adequately 
repaired  by  the  nutritive  processes  (§§  313,  347).  But  their  existence  as  living 
structures  appears  to  be  terminable  at  any  time,  by  the  exercise  of  their  functional 
powers ;  for  the  development  of  muscular  contractility  or  of  nervous  force  seems 
to  involve,  as  its  necessary  condition,  the  metamorphosis  (so  to  speak)  of  the 
vital  power  which  was  previously  exercising  itself  in  the  nutritive  operations } 
and  the  materials  of  these  tissues,  now  reduced  to  the  condition  of  dead  matter, 
undergo  those  regressive  changes  which  speedily  convert  them  into  excrementi- 
tious  products.  But  the  very  manifestation  of  their  peculiar  vital  endowments 
determines  an  afflux  of  blood  towards  the  parts  thus  called  into  special  activity; 
and  from  this  it  comes  to  pass  that  the  nutrition  of  these  textures  is  promoted, 
instead  of  being  impaired,  by  the  losses  to  which  they  are  thus  subjected ;  so 
that  their  constant  exercise  occasions  an  augmentation,  rather  than  a  diminution, 
of  their  substance — a  due  supply  of  the  requisite  materials  being  always  pre- 


590.  Thus  it  comes  to  pass  that,  during  the  whole  period  of  active  life,  a 
demand  for  Nutrition  is  created  by  every  exertion  of  the  vital  powers,  but  more 
especially  by  the  evolution  of  the  Nervous  and  Muscular  forces.  The  production 
and  application  of  these,  indeed,  may  be  considered  as  the  great  end  and  aim  of 
the  Human  organism,  so  far  at  least  as  the  individual  is  concerned ;  the  whole 
apparatus  of  Organic  life  being  subservient  to  the  building  up  and  maintenance 
of  the  Nervo-muscular  apparatus,  and  of  those  parts  of  the  fabric  (e.  g.  the  bones, 
cartilages,  fibrous  textures,  &c.)  which  it  uses  as  its  mechanical  instruments. 
Thus  the  activity  of  all  the  organic  operations,  when  once  the  full  measure  of 
growth  has  been  attained,  is  mainly  determined  by  that  of  the  animal  functions  j 
and  as  the  "  rate  of  life"  of  all  the  parts  which  minister  to  the  former  will  be 
in  proportion  to  the  energy  with  which  they  are  called  upon  to  perform  their 
functions,  their  duration  will  diminish  in  the  same  proportion,  and  hence  occa- 
sion will  arise  for  their  continual  renewal.1  But  since,  in  the  attainment  of  the 

1  Such  an  excellent  illustration  is  afforded  by  the  phenomena  of  Vegetation,  of  the 
doctrines  here  propounded,  that  it  would  be  scarcely  desirable  to  pass  it  by  in  this  place, 
although  it  has  been  elsewhere  more  fully  referred  to  ("  Princ.  of  Phys.,  Gen.  and  Comp.," 
\\  494,  554). — The  leaves  of  Plants  serve,  like  the  absorbing  and  assimilating  cells  of 
Animals,  for  the  introduction  and  elaboration  of  the  nutritive  materials  which  are  to  be  ap- 
plied to  the  extension  of  the  fabric,  the  more  permanent  and  inactive  parts  of  which  are 
thus  generated  at  the  expense  of  materials  prepared  by  the  vital  operations  of  the  more 
transitory  and  energetic.  Now  there  is  an  obvious  limit  to  the  duration  of  the  leaf-cells ; 
but  this  limit  is  not  precisely  one  of  time,  being  rather  dependent  upon  the  completion 
of  their  series  of  vital  actions.  Thus,  although  we  are  accustomed  to  look  upon  the  "fall 
of  the  leaves"  (which  is  nothing  else  than  an  exuviation  consequent  upon  death)  as  a 
phenomenon  of  regular  seasonal  recurrence,  and  to  regard  their  replacement  by  a  new 
growth  as  occurring  at  a  not  less  constant  interval,  yet  experience  shows  that  these 
intervals  are  entirely  regulated  by  temperature ;  for  if  one  of  the  ordinary  deciduous 
trees  of  temperate  climates  be  transferred  to  a  tropical  climate,  it  will  live  much  faster, 


FORMATIVE   POWER   OF   INDIVIDUAL   PARTS.  551 

adult  condition,  the  germinal  capacity  has  undergone  a  gradual  diminution, 
whilst  the  exercise  of  the  animal  powers  has  become  vastly  increased,  the  forma- 
tive processes  are  only  capable  of  maintaining  the  organism  in  its  state  of  com- 
pleteness and  vigor,  by  making  good  the  losses  consequent  upon  the  continual 
disintegration  to  which  it  is  subjected  by  its  nervo-muscular  activity  (§  132). 
And  with  the  advance  of  years,  the  further  diminution  of  the  reproductive 
capacity  involves,  on  the  one  hand,  a  progressive  decrease  in  the  substance  of 
the  tissues  and  organs  most  important  to  life  (their  bulk,  however,  frequently 
remaining  unchanged,  or  even  increasing,  in  consequence  of  the  accumulation 
of  fat),  and  on  the  other,  a  gradual  weakening  of  its  powers  of  action  (§  133). 
591.  The  performance  of  the  function  of  Nutrition,  the  demand  for  which 
arises  out  of  the  causes  that  have  been  now  discussed,  is  dependent,  not  merely 
upon  a  due  supply  of  pure  and  well-elaborated  blood,  but  also  upon  the  normal 
condition  of  the  part  to  be  nourished,  and  especially  upon  its  possession  of  a 
right  measure  of  "  formative  capacity  •"  in  virtue  of  which,  the  newly  produced 
tissues  are  generated  in  the  likeness,  as  well  as  in  the  place,  of  those  which  have 
become  effete.  The  exactness  of  this  replacement  is  most  remarkably  shown  in 
the  retention  of  the  characteristic  form  and  structure  of  each  separate  organ  or 
part  of  the  body,  and  thus  of  the  entire  organism,  through  a  long  series  of  years ; 
no  changes  being  apparent  (so  long  as  the  state  of  health  is  preserved),  but  such 
as  are  conformable  to  the  general  type  of  that  alteration  which  the  organism 
undergoes  with  the  advance  of  life.  And  not  only  is  this  to  be  noticed  in  the 
conservation  of  all  those  distinguishing  points  of  structure  which  mark  the 
species,  and  are  essential  to  its  well-being ;  but  it  is  still  more  remarkably  dis- 
played in  the  continuous  renewal  of  those  minor  peculiarities,  which  constitute 
the  characteristic  features  of  the  individual,  and  which  serve  to  distinguish  him 
from  his  fellows.  And  how  much  this  depends  upon  the  formative  capacity 
originally  derived  from  the  germ,  is  evident  from  this,  that  a  similar  moulding 
(so  to  speak)  of  the  nutritive  material  takes  place,  in  the  first  instance,  into  the 
form  characteristic  of  the  species,  and  afterwards  into  that  which  marks  the 
individual,  and  that  the  peculiarities  of  the  individual  are  frequently  such  as 
have  been  distinctive  of  one  or  other  of  the  parents,  or  present  a  combination  of 
both.  But  it  is  curious  that  the  formative  power  should  often  be  exercised,  not 
only  in  maintaining  the  original  type,  but  also  in  keeping  up  some  acquired 
peculiarity;  as,  for  example,  in  the  perpetuation  of  a  cicatrix  left  after  the 
healing  of  a  wound.  For,  as  Mr.  Paget  has  remarked,  the  tissue  of  a  cicatrix 
grows  and  assimilates  nutrient  material,  exactly  as  do  its  healthy  neighboring 
tissues ;  so  that  a  scar  which  a  child  might  have  said  to  be  as  long  as  his  own 
forefinger,  will  still  be  as  long  as  his  forefinger  when  he  becomes  a  man.  And 
when  the  mode  of  nutrition  in  any  part  has  been  altered  by  disease,  there  is 
frequently  an  obstinate  tendency  to  the  perpetuation  of  the  same  alteration  ;  or,  if 
the  healthy  action  be  for  a  time  restored,  there  is  a  peculiar  tendency  to  the  renewal 
of  the  morbid  process  in  the  part ;  and  this  is  stronger  the  more  frequently  it 
recurs,  until  at  last  it  becomes  inveterately  established.  There  is,  however,  in  the 
tissues  generally,  as  in  the  blood  (§  207),  a  general  tendency  to  a  return  to  the 
normal  type,  after  it  has  undergone  a  temporary  perversion ;  and  thus  it  is  that  we 
find  the  normal  structure  of  parts  gradually  restored,  when  the  morbid  tendency 
has  been  overcome;  and  that  even  cicatrices  and  indurations,  notwithstanding  their 
usual  obstinate  persistence,  occasionally  disappear.  The  normal  type  is,  perhaps, 
less  likely  to  be  thus  recovered,  when  the  departure  from  it  is  very  slight,  and 

its  leaves  being  shed  far  more  frequently,  and  being  replaced  much  more  speedily ;  so  that 
two,  or  even  three,  successive  exuviations  and  reproductions  of  its  foliage  may  take  place 
"within  a  year. 


552  OF   NUTRITION. 

consists  rather  in  the  wrong  plan  (so  to  speak)  on  which  the  new  matter  is  laid 
down,  than  in  a  perversion  of  the  nutritive  process  itself. 

592.  Of  the  mode  in  which  the  substitution  of  new  tissue  for  that  which  has 
become  effete,  is  effected  in  the  process  of  Nutrition,  our  knowledge  is  at  present 
limited  ;  but  there  can  be  little  doubt  that  it  nearly  always  takes  place  in  a 
manner  closely  conformable  to  the  first  development  of  each  tissue.     In  some 
instances  there  is  an  obvious  replacement  of  the  old  and  dead  by  the  young  and 
active  elements :  this  is  the  case,  for  example,  in  the  constantly-repeated  pro- 
duction of  the  Epidermic  and  Epithelial  layers ;  for  whether  they  are  developed 
from  germs  imbedded  in  the  subjacent  basement-membrane,  or  from  nuclei 
formed  de  novo  in  the  blastema  on  its  free  surface,  or  by  the  duplicative  subdivi- 
sion of  pre-existing  cells,  there  is  a  continual  succession  of  new  cells,  which  take 
the  place  of  those  that  are  cast  off  as  defunct  and  useless.     So  in  the  growth  of 
Hair,  the  increase   of  which  takes  place  only  at  its  base,  we  can  trace  at  any 
period  the  same  development  of  newly  formed  spheroidal  cells  into  horny  fusi- 
form fibres,  as  that  which  took  place  when  first  the  hair  began  to  sprout  from  the 
aggregation  of  epidermic  cells  at  the  bottom  of  its  follicle.     So,  again,  in  the 
vesicular  tissue  which  constitutes  the  essential  part  of  the  Nervous  centres, 
there  are  appearances  which  indicate  that  its  peculiar  cells  are  in  a  state  of 
continual  development,  newly  formed  ganglionic  vesicles  taking  the  place  of 
those  which  have  undergone  disintegration.     But  there  are  other  textures  whose 
nutrition  is  more  completely  interstitial;  their  elements  being  more  closely 
coherent,  and  their  newly-formed  portions  being  developed  throughout  the  sub- 
stance of  the  old,  instead  of  (as  in  the  case  of  the  epidermis  and  its  appendages) 
superficially  or  in  mere  continuity  with  it.     Such  is  the  case,  for  example,  with 
Muscle,  the  mode  of  whose  nutrition  has  not  yet  been  elucidated.     We  can  only 
infer  from  analogy,  that  here  too  each  fibre  or  fibril  will  pass,  in  the  course  of 
its  development,  through  the  same  stages  which  those  of  the  embryo  did  when  its 
muscles  were  first  formed.     And  this  analogy  seems  to  derive  confirmation,  from 
the  presence,  in  all  well-nourished  muscles,  of  bodies  which  bear  the  appearance 
of  nuclei ;  for  these,  as  Mr.  Paget  remarks,  "  are  not  the  loitering  impotent  re- 
mains of  embryonic  tissue,  but  germs  or  organs  of  power  for  new  formation." 
And  it  is  further  confirmatory  of  this  view,  that  losses  of  substance  of  muscle, 
which  involve  the  destruction  of  these  centres  of  nutrition,  are  not  replaced,  like 
losses  of  cuticle,  by  new  tissue  of  the  same  kind  j  the  power  to  form  it  not  being 
inherent  in  the  blood  or  in  the  neighboring  parts.     Nevertheless,  it  must  be 
admitted  that  no  intermediate  stages  of  development  can  be  traced  in  the  fibres, 
even  of  those  muscles  of  the  adult  which  are  in  most  constant  use,  and  of  which 
the  nutrition  is  the  most  active,  that  are  at  all  comparable  to  those  which  are 
met  with  in  the  muscular  tissues  of  the  embryo. — With  regard,  again,  to  the 
interstitial  nutrition  of  Bones  and  Teeth,  we  know  nothing  whatever.     That 
some  nutritive  change  is  continually  taking  place  in  them,  is  certain  from  the 
fact  that  if  the  supply  of  blood  be  withdrawn,  the  parts  thus  affected  die  and 
are  cast  out  of  the  body ;  and  it  is  also  made  apparent  by  the  effects  of  madder  in 
gradually  tinging  even  the  bones  and  teeth  of  the  adult,  though  for  such  a 
change  a  much  longer  period  is  required  in  the  adult  than  in  the  young  animal. 
— The  nutrition  of  the  simple  Fibrous  tissues  would  also  appear  to  take  place 
interstitially ;  but  there  is  no  proof  that  the  pre-existing  tissues  are  here  in  any 
way  concerned  in  their  replacement,  which  probably  takes  place  in  virtue  of  the 
self-developing  powers  of  the  blood  itself. 

593.  Of  the  modes  in  which  the  effete  particles  of  tissues  whose  term  of  life 
has  expired,  or  whose  vital  energy  has  been  exhausted,  are  removed  and  disposed 
of,  our  present  knowledge  is  no  less  imperfect.     In  the  case  of  those  tissues 
which  are  superficially  nourished,  a  continual  loss  of  substance  is  obviously 
taking  place  by  the  exuviation  of  dead  particles  en  masse  ;  this  is  the  case  with 


FORMATIVE   POWER    OP   INDIVIDUAL   PARTS.  553 

the  whole  series  of  Epithelial  and  Epidermic  cells,  which  are  thrown  off  with 
little  previous  change,  like  the  leaves  of  trees,  their  decay  not  taking  place,  for 
the  most  part,  until  after  they  have  become  detached  from  the  organism.  But 
the  fact  is  altogether  different  with  regard  to  those  whose  nutrition  is  interstitial, 
especially  the  nervous  and  muscular  tissues ;  for  the  decomposition  of  these 
would  seem  to  occur  in  their  very  substance,  its  products  being  taken  up  by  the 
blood,  and  subsequently  eliminated  from  it  by  organs  appropriated  to  that  pur- 
pose. The  evidence  of  this  is  seen,  as  regards  Muscle,  in  the  presence  of  crea- 
tine,  creatinine,  inosite,  and  other  undoubted  products  of  regressive  metamorpho- 
sis, in  the  "juice  of  flesh ;"  as  regards  the  Nervous  substance,  however,  no  such 
definite  proof  can  be  at  present  afforded,  since  its  normal  constitution  has  not 
yet  been  sufficiently  studied  to  enable  the  products  of  its  decomposition  to  be 
distinguished. — There  is  one  remarkable  form  of  degeneration,  however,  which 
is  common  to  nearly  all  the  tissues,  and  which  seems  to  occur  as  a  normal  altera- 
tion in  many  of  them  at  an  advanced  period  of  life ;  this  consists  in  the  conver- 
sion of  their  albuminous  or  gelatinous  materials  into  fat,  thus  constituting  what 
is  known  as  "  fatty  degeneration/'  That  this  change  is  not  due  to  the  removal 
of  the  normal  components  of  the  tissues,  and  the  substitution  of  newly  deposited 
fatty  matter  in  their  place,  but  is  (in  most  cases  at  least)  the  result  of  a  real 
conversion  of  the  one  class  of  substances  into  the  other,  has  been  already  pointed 
out  (§  40).  And  there  are  certain  facts  which  indicate  that  this  kind  of  degene- 
ration is  a  part  of  the  regular  series  of  processes,  by  which  tissues  that  have 
served  their  purpose  in  the  economy  are  prepared  for  being  removed  by  absorp- 
tion ;  one  of  the  most  remarkable  being  the  observations  of  Virchow1  and  Kilian3 
with  regard  to  the  fatty  degeneration  of  the  muscular  tissue  of  the  uterus  after 
parturition.  So,  as  Mr.  Paget  has  pointed  out,  the  fibrinous  and  corpuscular 
products  of  inflammation  are  often  brought  into  a  state  fit  for  absorption,  by  pass- 
ing through  this  intermediate  stage  ;  the  fibrinous  substance  being  observed  to 
be  dotted  by  granules,  which  are  known  to  be  oil  particles  by  their  peculiar 
shining  black-edged  appearance,  and  at  the  same  time  losing  its  toughness  and 
elasticity,  and  being  no  longer  rendered  transparent  by  acetic  acid  j  whilst  the 
lymph-cells  present  a  similar  increase  of  shining  black-edged  particles  like 
minute  oil-drops,  which  accumulate  until  they  nearly  fill  the  cell-cavity,  their 
nuclei  at  the  same  time  gradually  fading  and  disappearing.3  Thus,  then,  if  the 
fat,  which  is  one  of  the  products  of  this  regressive  metamorphosis,  be  absorbed 
as  fast  as  it  is  formed,  and  the  effete  tissue  be  replaced  by  a  new  production, 
which  seems  to  be  the  case  with  Muscles  in  a  state  of  healthy  activity,  there  is 
no  appearance  of  degeneration,  and  the  nutrition  is  kept  up  to  its  normal  stand- 
ard. But  if,  from  the  advance  of  age  or  from  the  insufficient  exercise  of  the 
muscles,  their  nutrition  take  place  less  rapidly  than  their  waste,  whilst  the  pro- 
ducts of  their  degeneration  are  still  removed,  simple  atrophy  is  the  result.  If, 
on  the  other  hand,  the  general  conditions  being  similar,  the  fat  produced  in 
degeneration  be  not  absorbed,  but  remain  in  the  tissue  (as  is,  perhaps,  most 
likely  to  happen  when  a  copious  supply  of  respiratory  material  is  afforded  by 
other  substances),  an  obvious  "  fatty  degeneration' '  is  the  result. — It  may  be 
stated  as  a  general  rule  that  no  absorption  of  the  materials  of  tissue  can  take 
place  without  a  previous  degeneration  such  as  this,  or  a  more  complete  decom- 
position. There  is  no  evidence  that  any  healthy  tissue  is  ever  thus  absorbed,  or 
that  any  preternatural  activity  of  the  absorbent  vessels  can  ever  (as  formerly 
supposed)  be  the  occasion  of  a  loss  of  substance ;  in  fact,  so  long  as  the  vital 
force  is  in  active  operation  in  a  part,  and  its  processes  of  growth  and  develop- 

1  "  Verliandlungen  der  Gesellschaft  fur  Geburtshiilfe,"  Berlin,  vol.  iii.  p.  xvii. 

2  "  Henle  und  Pfeuffer's  Zeitschrift,"  vol.  ix.  p.  1. 

3  See  Mr.  Paget' s" Lectures  on  Inflammation,"  in  "Medical  Gazette, "1850,  vol.  xlv.  p.  7. 


554  OP   NUTRITION. 

ment  are  being  normally  carried  on,  such  absorption  may  be  considered  to  be 
impossible.  On  the  other  hand,  if  a  part  die  en  masse,  it  is  not  removed  by 
absorption,  but  becomes  isolated  by  the  separation  and  recedence  of  the  living 
parts,  and  is  then  cast  out  altogether,  even  from  the  interior  of  the  body  as  we 
see  in  the  case  of  a  necrosed  bone  ;  its  condition  being  then  essentially  the  same 
as  that  of  the  outer  layers  of  the  tegumentary  organs,  which  are  cut  off,  by  their 
distance  from  a  vascular  surface,  from  all  further  nutrient  change.  The  differ- 
ence between  these  two  modes  of  removal  is  well  seen  (as  Mr.  Paget  has  re- 
marked) in  the  case  of  the  Teeth ;  for  the  fangs  of  the  deciduous  teeth  undergo 
degeneration,  when  the  current  of  nutrition  is  diverted  towards  those  which  are 
to  succeed  them,  their  materials  being  slowly  decomposed  so  as  to  become  soluble, 
and  being  gradually  removed  by  absorption,  so  that  nothing  is  left  at  last  but 
the  crowns  of  the  teeth ;  on  the  other  hand,  the  permanent  teeth  which  are  not 
to  be  succeeded  by  others,  when  no  longer  receiving  their  due  nutrition,  die,  and 
are  cast  out  entire. 

594.  Among  the  conditions  of  healthy  Nutrition,  a  due  supply  of  Nervous 
power  is  commonly  enumerated ;  and  it  cannot  be  questioned  that  the  want  of 
such  a  supply  is  frequently  the  source  of  a  perversion  of  the  normal  operations. 
This,  however,  by  no  means  proves  that  the  formative  power  is  derived  from 
the  nervous  system ;  and  such  an  idea  is  at  once  negatived  by  a  number  of  in- 
contestable facts.     Yet  it  may  be  freely  admitted  that  the  right  direction  and 
application  of  this  power  in  Nutrition  may  sometimes  depend  upon  guidance 
and  direction  afforded  by  the  Nervous  centres,  in  the  same  manner  as  the  Secret- 
ing process  is  capable  of  being  thus  influenced ;  in  fact,  we  can  scarcely  explain 
in  any  other  mode  that  influence  of  mental  states  upon  the  nutrient  operations, 
which  frequently  leads  to  very  important  modifications  of  them.     The  whole 
of  this  subject,  however,  will  be  more  appropriately  considered  hereafter  (CHAP. 
XVII.).1 

2. —  Varying  Activity  of  the  Nutritive  Processes. — Reparative  Operations. 

595.  Without  any  change  in  the  character  of  the  Nutritive  processes,  there 
may  be  considerable  variations  in  their  degree  of  activity  ;  and  this,  either  as 
regards  the  entire  organism,  or  individual  parts,  though  most  commonly  the 
latter.     These  variations  may  be  so  considerable  as  to  constitute  Disease ; 
though  there  are  some  which  take  place  as  part  of  the  regular  series  of  Physio- 
logical phenomena.     Thus,  as  we  have  seen,  it  is  to  the  excess  of  formative 
activity,  that  the  increase  of  the  organism  in  the  earlier  period  of  life  is  due,  its 
"  waste"  being  at  the  same  time  extremely  rapid ;  whilst  it  is  to  a  correspond- 
ing reduction  in  the  regenerative  power,  and  not  to  positive  excess  of  "waste" 
or  decay  (this,  indeed,  taking  place  very  slowly),  that  the  gradual  decline  of 
the  organism  in  advancing  years  is  to  be  attributed.     So  also  we  find  that  local 
as  well  as  general  variations  may  take  place,  as  a  part  of  the  regular  series  of 
vital  phenomena ;   and  this  during  the  period  of  adult  life,  as  well  as  in  the 
earlier  and  later  epochs.     Thus  all  those  differences  in  the  proportional  develop- 
ment of  the  several  parts  of  the  organism,  which  mark  the  distinction  between 
the  adult  and  the  child,  even  where  (as  in  the  case  of  a  dwarf),  there  is  no  dif- 
ference in  stature,  result  from  a  decline  in  the  formative  capacity  of  those  which 
are  peculiarly  adapted  to  the  wants  of  the  earlier  stage  (the  Thymus  gland,  for 
example),  and  from  an  increased  activity  of  nutrition  in  tnose  which  are  destined 
to  the  use  of  the  adult,  the  Generative  organs  more  particularly.     And  the 

1  In  the  treatment  of  this  subject,  the  Author  has  made  free  use  of  the  valuable  materials 
contained  in  Mr.  Paget's  "Lectures  on  Nutrition,  Hypertrophy,  and  Atrophy"  ("Med. 
Gaz.,"  1847),  which  have  enabled  him,  whilst  still  expressing  the  same  general  doctrines  as 
in  previous  editions,  to  make  great  improvements  in  the  exposition  and  illustration  of  them. 


HYPERTROPHY.  555 

intermittent  activity  of  the  sexual  apparatus  of  the  finale  affords  a  remarkable 
example  of  the  same  principle ;  this  being  marked  not  merely  in  the  enormous 
development  of  the  uterus  and  mammary  glands,  as  a  consequence  of  conception, 
but  in  the  periodical  change  which  takes  place  in  the  ovaries,  whereby  the  ova 
are  matured  and  thrown  off  at  certain  regular  intervals.  The  decline  in  the 
formative  power  of  these  same  organs,  moreover,  when  as  yet  the  organism  in 
general  shows  but  little  indication  of  deterioration,  is  another  characteristic 
example  of  the  variation  in  Nutritive  activity  resulting  from  the  inherent  en- 
dowments of  the  part,  and  essentially  irrespective  of  the  condition  of  the  blood, 
of  the  circulation,  and  of  the  organism  as  a  whole ;  but,  as  formerly  shown 
(§  203),  the  production  and  maintenance  of  other  and  apparently  unconnected 
organs  are  complementalty  dependent  upon  the  formative  activity  of  the  genera- 
tive apparatus. 

596.  The  abnormal  excess  of  Nutritive  change  which  properly  constitutes 
Hypertrophy,  appears  to  depend  upon  a  departure  from  one  or  other  of  the  con- 
ditions, under  which,  as  already  specified,  the  change  normally  takes  place ; 
namely,  the  right  composition  of  the  blood,  a  due  supply  of  such  blood,  and  a 
proper  formative  capacity  in  the  part  itself. — Of  the  excess  of  nutrition  result- 
ing from  the  presence  of  an  excess  of  the  peculiar  materials  of  certain  tissues  in 
the  circulating  fluid,  examples  have  already  been  given  (§  120)  ;  it  is  important 
to  remark,  however,  that,  although  hypertrophy  may  be  thus  induced  in  any  of 
the  tissues  which  constitute  the  instruments  of  organic  life,  yet  there  is  no  evi- 
dence that  either  the  nervous  or  the  muscular  apparatus  can  be  forced  (so  to 
speak)  to  an  augmentation  in  bulk  by  the  abundance  of  their  nutritive  materials. 
— With  regard,  in  the  next  place,  to  the  supply  of  blood,  there  can  be  no  doubt 
that  in  general  an  increased  flow  of  blood  towards  a  part  is  consequent  upon, 
rather  than  a  cause  of,  an  excess  in  its  nutritive  activity  j  but  still,  there  are 
cases  in  which  its  causative  agency  may  be  traced.  Various  examples  of  this 
have  been  supplied  by  the  experiments  and  observations  of  John  Hunter,  the 
records  of  which  are  left  in  his  Museum.  Thus,  if  the  spur  of  a  cock  be  trans- 
planted from  the  leg  to  the  comb,  which  is  a  part  far  more  vascular  than  that 
with  which  it  was  originally  connected,  it  undergoes  an  extraordinary  augmenta- 
tion in  size ;  having  in  one  instance  grown  in  a  spiral  form,  until  it  was  six 
inches  long ;  and  in  another  curved  forwards  and  downwards  like  a  horn,  so 
that  its  end  needed  to  be  often  cut,  to  enable  the  bird  to  bring  his  beak  to  the 
ground  in  feeding.  So,  again,  it  was  remarked  by  Hunter,  and  has  been  fre- 
quently observed  since,  that  an  increased  growth  of  hair  often  takes  place  on 
surfaces  to  which  there  is  an  increased  determination  of  blood  as  a  consequence 
of  inflammation  in  some  neighboring  part,  though  not  from  the  surface  of  the 
inflamed  part  itself.  So  it  sometimes  happens  that  when  an  ulcer  of  the  integu- 
ments of  the  leg  has  long  existed  in  a  young  person,  the  subjacent  bone  may 
share  in  the  increased  afflux  of  blood,  and  may  enlarge  and  elongate.  And  it 
seems  not  improbable  that  we  are  to  attribute  the  increased  thickness  of  the 
cuticle  on  parts  which  are  exposed  to  continual  pressure  or  friction,  to  the  aug- 
mented afflux  of  blood  which  is  determined  to  the  irritated  surface  (§  241). * — 
The  greater  number  of  cases  of  Hypertrophy,  however,  must  undoubtedly  be 
referred  to  the  preternatural  formative  capacity  of  the  part  itself ;  and  this  may 
either  be  congenital  or  acquired.  Of  this  congenital  excess,  we  have  a  remark- 
able example  in  the  abnormal  growth  of  an  entire  limb,  or  of  fingers  or  toes,2 
> 

1  It  is  commonly  said  that  local  hypertrophy  may  be  induced  by  long-continued  Conges- 
tion; but  this  is  not  true  hypertrophy ;  for  the  bulk  of  the  organ  is  not  augmented  by  the 
increased  production  of  its  normal  tissue,  but  by  the  addition  of  tissue  of  an  inferior  type  of 
organization,  as  in  Inflammation  ($  609). 

2  A  case  of  hypertrophy  of  an  entire  limb  was  described  by  Dr.    John  Jleid  in  the 
"Edinb.  Monthly  Journ.,"  1843,  p.  198;  and  several  cases  of  hypertrophy  of  the  fingers 
were  described  by  Mr.  Curling  in  the  "  Med.-Chir.  Trans.,"  vol.  xxviii. 


556  OF   NUTRITION. 

which  cannot  with  any  probability  be  referred  to  an  original  excess  in  the  supply 
of  blood,  the  enlargement  of  the  arteries  leading  towards  such  parts  being  almost 
certainly  consequent  upon  their  unusually  rapid  growth,  just  as  in  the  case  of 
the  uterine  and  mammary  arteries  of  the  pregnant  female.  The  most  remark- 
able instances  of  the  acquirement  of  increased  formative  activity,  are  presented 
to  us  in  that  augmented  growth  of  the  nervous  and  muscular  tissues,  which  is 
consequent  upon  the  exercise  of  their  functional  powers.  This  may  be  con- 
sidered as  to  a  certain  extent  a  normal  adjustment  of  the  supply  to  the  demand; 
but  there  are  some  instances  in  which  it  takes  place  to  such  an  extent  as  to 
become  a  positive  disease.  Thus  it  not  unfrequently  happens,  that  if  young 
persons  who  naturally  show  precocity  of  intellect,  are  encouraged  rather  than 
checked  in  the  use  of  the  brain,  the  increased  nutrition  of  the  organ  (which 
grows  faster  than  its  bony  case)  occasions  pressure  upon  its  vessels,  it  becomes 
indurated  and  inactive,  and  fatuity  and  coma  may  supervene.  Now  although 
in  such  cases  there  must  probably  have  been  some  congenital  tendency  to  pre- 
ternatural activity  of  the  brain,  which  manifests  itself  in  precocity  of  intellect, 
yet  there  is  no  doubt  that  this  may  be  augmented  by  the  "  forcing  system'7  of 
education ;  whilst,  on  the  other  hand,  it  may  be  controlled  by  a  system  of 
management  adapted  to  the  peculiar  circumstances  of  the  case.  Excess  of 
muscular  development  is  peculiarly  prone  to  show  itself  in  the  involuntary 
muscles ;  but  this  production  is  in  almost  every  instance  the  result  of  the 
demand  for  increased  muscular  exertion,  which  is  consequent  upon  some  obstruc- 
tion to  the  usual  function  of  the  part.  Thus  an  extraordinary  hypertrophy  of 
the  muscular  coat  of  the  urinary  bladder  is  often  seen  as  a  consequence  of  ob- 
struction to  the  exit  of  the  urine,  through  the  presence  of  a  stone  in  the  bladder 
or  of  a  stricture  in  the  urethra ;  so,  again,  hypertrophy  of  the  muscular  coat  of 
the  gall-bladder  may  take  place  as  a  consequence  of  obstruction  of  its  duct  by  a 
gall-stone ;  hypertrophy  of  the  muscular  coat  of  any  part  of  the  alimentary  canal 
may  take  place  in  consequence  of  stricture  lower  down ;  and  even  hypertrophy 
of  the  heart  is  generally,  if  not  always,  attributable  to  obstruction  to  the  exit  of 
the  blood  which  it  propels,  resulting  either  from  stagnation  of  the  pulmonary 
circulation  by  the  deficient  aeration  consequent  upon  disease  of  the  lungs  (in 
which  case  the  hypertrophy  is  limited  to  the  right  side  of  the  heart),  or  from 
thickening  or  induration  of  the  semilunar  valves  or  narrowing  of  the  orifices  of 
the  aorta  and  pulmonary  artery.  It  is  curious,  moreover,  to  observe  that  hyper- 
trophy of  muscles  frequently  becomes  a  source  of  increased  nutrition  of  the 
bones  to  which  they  are  attached ;  this  being  manifested,  not  merely  in  the 
augmented  bulk  of  the  bones  of  limbs  that  are  specially  exercised,  but  also  in 
the  increased  prominence  of  the  ridges  and  processes  to  which  the  muscles  are 
attached.  This  adaptiveness  on  the  part  of  the  formative  activity  of  the  osseous 
tissue,  is  curiously  manifested  also  in  the  relation  of  the  skull  to  the  brain ; 
for  if  the  bulk  of  the  brain  be  not  too  rapidly  augmented,  the  skull  will  enlarge 
accordingly,  and  this  (in  some  instances)  not  merely  by  the  extension  of  its 
normal  bones,  but  by  the  intercalation  of  new  osseous  elements,  the  "  ossa 
wormiana ',"  whilst,  on  the  other  hand,  if  there  be  a  diminution  in  the  bulk  of 
the  brain,  the  cranium  may  adapt  itself  to  this  also,  by  a  thickening  on  its  in* 
ternal  surface,  or  concentric  hypertrophy — this  change,  rather  than  a  diminu- 
tion in  the  whole  substance  of  the  skull,  being  more  liable  to  take  place  in  cases 
in  which  the  cranial  sutures  have  already  closed,  and  the  nutrition  of  the  bone 
has  become  inactive,  so  that  the  modelling  process,  which  consists  in  the  ab- 
sorption of  old  and  the  deposition  of  new  osseous  tissue  (§  130),  cannot  take 
place. 

597.  The  production  of  Tumors  must  be  considered  as  a  manifestation  of  an 
excess  of  formative  activity  in  individual  parts,  and  as  constituting,  therefore, 
a  species  of  Hypertrophy.  For  a  tumor  may  be  composed  of  the  tissues  which 


HYPERTROPHY; — TUMORS.  557 

are  normal  to  the  part ;  as  we  see  especially  in  the  case  of  those  tumors  of  the 
uterus,  which  are  made  up  of  an  excess  of  its  ordinary  muscular  and  fibrous 
elements.  But,  as  Mr.  Paget  has  justly  remarked,  "  an  essential  difference  lies 
in  this;  the  uterus  (often  itself  hypertrophied)  in  its  growth  around  the  tumor 
maintains  a  normal  type,  though  excited  to  its  growth,  if  we  may  so  speak,  by 
an  abnormal  stimulus ;  it  exactly  imitates,  in  vascularity  and  muscular  develop- 
ment, the  pregnant  uterus,  and  may  even  acquire  the  like  power ;  and  at  length, 
by  contractions  like  those  of  parturition,  may  expel  the  tumor  spontaneously 
separated.  But  the  tumor  imitates  in  its  growth  no  natural  shape  or  con- 
struction ;  the  longer  it  continues,  the  greater  is  its  deformity.  Neither  may 
we  overlook  the  contrast  in  respect  of  purpose,  or  adaptation  to  the  general 
welfare  of  the  body,  which  is  as  manifest  in  the  increase  of  the  uterus  as  it  is 
improbable  in  that  of  the  tumor."1  A  gradation  is  established,  however,  be- 
tween true  Hypertrophies  and  Tumors,  by  those  productions  of  glandular 
tissue,  which  are  made  up  of  the  proper  substance  of  the  gland  with  which  they 
are  connected,  as  the  mammary,  the  prostate,  or  the  thyroid,  and  which  (though 
frequently  encysted)  are  sometimes  met  with  as  outlying  portions  of  the  gland 
itself. — There  is  another  class  of  objects  to  which  Tumors  come  into  close 
relation,  and  which  must  be  referred,  like  them,  to  a  local  excess  of  formative 
activity ;  these  are  the  "  supernumerary  parts"  which  are  not  unfrequently  de- 
veloped during  foetal  life,  as,  for  example,  additional  fingers  and  toes.  It  seems 
absurd  to  refer  these,  formed  as  they  are  by  simple  outgrowth  from  the  limbs  to 
which  they  are  attached,  to  the  "  fusion  of  germs,"  which  has  been  hypotheti- 
cally  invoked  to  explain  more  important  excesses,  as  those  of  additional  limbs, 
double  bodies,  or  double  heads ;  and  yet  from  the  lower  to  the  higher  form  of 
excess,  the  transition  is  so  gradual  that  what  is  true  of  the  former  can  scarcely 
but  be  true  of  the  latter ;  so  that  even  complete  "  double  monsters"  must  be 
regarded,  not  as  having  proceeded  from  two  separate  germs  which  have  become 
partially  united  in  the  course  of  their  development,  but  from  a  single  germ,  which, 
being  possessed  of  an  unusual  formative  capacity,  has  evolved  itself  into  a 
structure  containing  more  than  the  usual  number  of  parts,  and  comparable  to 
that  which  may  be  artificially  produced  by  partial  fission  of  the  bodies  of  many 
of  the  lower  animals. a — We  can  scarcely  fail  to  recognize,  in  this  whole  series 
of  abnormal  productions,  the  operation  of  a  similar  power.  In  the  formation 
of  a  supernumerary  part,  this  has  been  sufficient,  not  merely  to  produce  the 
tissues,  and  to  develop  them  according  to  a  regular  morphological  type,  but  to 
impart  to  the  fabric  thus  generated  a  separate  and  even  an  independent  existence ; 
thus  producing  an  additional  finger  or  thumb  on  each  hand,  a  double  pair  of 
arms  or  legs,  a  double  head  or  trunk,  or  even  a  complete  double  body.  In  the 
hypertrophy  of  a  regular  or  normal  part,  the  new  tissues  are  still  developed  ac- 
cording to  a  regular  morphological  type ;  but  they  have  not  the  power  of  indi- 
vidualizing themselves  (so  to  speak),  and  are  so  incorporated  with  the  normal 
elements  as  to  augment  the  size  of  the  existing  organ.  In  the  formation  of  a 
tumor,  on  the  other  hand,  whilst  its  component  tissues  are  themselves  perfectly 
formed,  and  have  a  marked  power  of  independent  growth,  the  mass  composed 
of  them  is  altogether  amorphous,  its  configuration  being  usually  determined 
rather  by  the  physical  conditions  under  which  it  is  produced,  than  by  any 
peculiar  tendencies  of  its  own ;  so  that  we  recognize  the  action  of  the  formative 
power,  undirected  by  that  morphological  nisus,  which  normally  models  (so  to 
speak)  the  growing  tissues  into  the  likeness  of  the  organ  to  which  they  belong. 

1  "Lectures  on  Tumors,"  in  "  Medical  Gazette,"  1851,  vol.  xlvii.  p.  925. 

2  See  "  Princ.  of  Phys.,  Gen.  and  Comp.,"  \\  646,  709,  Am.  Ed. ;  Prof.  Vrolik  in 
"Cyclop,  of  Anat.  and  Phys.,"  art.  "Teratology,"  vol.  iv.  p.  976;  and  Prof.  Allen  Thom- 
son on  "Double  Monstrosity,"  in  "Edinb.  Monthly  Journal,"  June  and  July,  1844. 


558  OF   NUTRITION. 

But  further,  in  many  of  the  large  class  of  tumors  distinguished  as  "  malignant" 
(§  616),  the  development  of  tissue  has  not  gone  to  the  extent  of  producing  any 
of  those  species  of  which  the  body  is  normally  constituted ;  and  in  this  respect 
as  well  as  in  their  tendency  to  rapid  degeneration,  the  vital  endowments  of  their 
elements  must  be  reckoned  as  below  those  of  the  normal  tissues.— It  is  not 
always  easy  to  draw  the  line  between  certain  tumors  and  supernumerary  parts, 
especially  when  the  production  of  the  former  is  symmetrical ;  but  the  first  ap- 
pearance of  the  latter  never  takes  place  save  during  embryonic  life,  and  their 
structure  is  more  complex,  and  is  more  conformed  to  the  plan  and  construction 
of  the  body  at  large,  than  is  that  of  tumors,  whose  production  may  take  place 
at  any  period  of  life.  And  between  those  tumors  which  are  known  as  "  pili- 
ferous"  and  "  dentigerous  cysts,"  and  those  encysted  embryos  (usually  incom- 
plete in  their  formation)  which  are  sometimes  found  in  the  bodies  even  of  males, 
it  is  impossible  to  establish  any  line  of  demarcation  sufficiently  precise  to  prevent 
our  recognizing  them  as  all  having  the  same  origin  and  being  expressions  of  the 
same  power — the  simple  cyst  being  a  kind  of  rude  attempt  at  the  production  of 
a  distinct  individual — and  the  encysted  embryo  being  but  the  result  of  an  un- 
usually high  development  of  a  proliferous  cyst. 

598.  The  state  of  Atrophy  is  in  all  respects  the  very  opposite  of  Hypertrophy; 
consisting  in  such  a  reduction  in  the  rate  of  formative  activity  as  compared  with 
that  of  their  u  waste/'  that  their  nutrition  is  no  longer  maintained  at  its  previous 
standard ;  so  that  they  are  gradually  reduced  in  bulk,  or  degenerate  into  some 
inferior  histological  type,  or  (which  is  the  more  common  occurrence)  undergo 
both  diminution  and  deterioration  at  the  same  time.  It  is  important  to  bear 
in  mind,  that  Atrophy  may  take  place,  either  locally  or  generally,  from  an  un- 
usually rapid  disintegration  of  the  tissues,  uncompensated  by  a  corresponding 
increase  in  the  rate  of  their  nutrition  ;  of  the  former  we  have  a  characteristic 
example  in  the  rapid  reduction  of  the  bulk  of  the  uterus  after  parturition,  and 
of  that  of  the  mammary  glands  after  the  sudden  cessation  of  lactation  ;  of  the 
latter  we  see  an  illustration  in  the  rapid  wasting  of  the  system,  which  takes 
place  in  the  irritable  state  that  results  from  excessive  and  prolonged  exertion  of 
body  or  anxiety  of  mind,  especially  when  accompanied  with  want  of  sleep,  the 
increased  disintegration  being  marked  by  the  presence  of  an  unusual  amount  of 
urea  and  of  the  alkaline  phosphates  in  the  urine.  But  in  the  ordinary  forms  of 
Atrophy,  there  is  not  merely  a  relative  but  an  absolute  reduction  in  the  rate  of 
the  formative  process,  or  a  lowering  of  its  standard  of  perfection ;  and  here  also 
we  have  to  look  for  its  causes,  on  the  one  hand,  in  the  condition  and  supply  of 
the  blood,  and,  on  the  other,  in  the  formative  capacity  of  the  tissues  themselves. 
— The  Atrophy  dependent  upon  an  insufficient  supply  of  nutritive  materials, 
may  be  either  general  or  partial.  General  atrophy,  or  emaciation,  is  a  neccessary 
result  of  deficiency  of  food;  but  it  may  also  proceed  from  an  imperfect  perform- 
ance of  the  assimilating  processes,  whereby  the  nutritive  materials  do  not  receive 
their  requisite  elaboration,  as  in  cases  of  disease  of  the  mesenteric  glands ; 
or  from  an  unusual  energy  of  the  metamorphic  processes,  whereby  the  azotized 
constituents  of  the  food  are  decomposed  into  excrementitious  products,  without 
undergoing  assimilation  at  all,  as  seems  to  be  the  case  in  diabetes.  Of  the 
atrophy  of  a  particular  tissue  consequent  upon  the  deficiency  of  its  proper 
materials  in  the  blood,  we  have  an  example  in  the  reduction  of  the  adipose, 
when  there  is  no  surplus  of  fatty  matter  to  serve  for  its  nutrition,  but  on  the 
other  hand  a  withdrawal  of  the  contents  of  the  fat-cells  into  the  circulating  cur- 
rent, whilst  the  nutrition  of  the  muscular  and  other  azotized  tissues  may  proceed 
with  its  usual  vigor. — Instances  of  complete  local  atrophy,  or  gangrene,  resulting 
from  deficiency  in  the  supply  of  blood  to  a  part,  are  by  no  means  unfrequent ; 
but  it  is  less  common  to  meet  with  a  prolonged  diminution  in  the  rate  of  nutri- 
tion from  such  a  cause,  since  a  partial  obstruction  to  the  circulation  is  usually 


ATROPHY.  559 

removed  after  a  short  time  by  the  enlargement  of  the  collateral  vessels.  Yet 
there  are  peculiar  circumstances  under  which  this  does  not  take  place  ;  thus 
Mr.  Curling  has  shown  that  atrophy  may  occur  in  fractured  bones,  in  that 
portion  which  is  cut  off  from  the  direct  supply  of  blood  through  the  great  medul- 
lary artery ;  the  circulation  being  restored  by  anastomosis  to  such  an  extent  as 
to  prevent  the  death  of  the  bone,  but  not  so  completely  as  to  support  vigorous 
nutrition.1 — The  most  frequent  cause  of  Atrophy  lies,  however,  in  the  deficiency 
of  formative  power  in  the  tissues  themselves,  arising  from  the  decline  of  that 
capacity  which  they  inherit  from  the  germ.  This  decline,  as  already  shown, 
takes  place  in  the  body  at  large,  as  a  part  of  the  regular  order  of  things,  with 
the  advance  of  years,  and  also  normally  occurs  in  particular  organs  at  earlier 
periods  of  life  ;  but  it  sometimes  takes  place  prematurely,  either  in  the  body  at 
large,  or  in  particular  organs,  so  that  they  undergo  a  wasting  or  degeneration 
without  any  ostensible  cause.  A  remarkable  example  of  this  has  been  already 
referred  to,  in  the  account  of  Cartilage  (§  253) ;  and  many  similar  cases  might 
be  cited.  There  is  reason  to  believe  that  "  fatty  degeneration/'  the  form  under 
which  degeneration  most  commonly  presents  itself  (§  593),  is  in  reality  far  more 
frequent  than  simple  wasting  of  the  tissues  ;  but  it  attracts  less  notice,  because 
their  bulk  is  little  or  not  at  all  diminished  ;  and  it  is  only  when  their  function 
becomes  impaired,  that  attention  is  seriously  drawn  to  the  change.  This  form  of 
Atrophy  can  seldom  be  attributed  to  antecedent  diminution  in  functional  activity; 
for  it  is  most  common  in  organs  upon  which  there  is  the  most  constant  demand  for 
the  energetic  performance  of  their  respective  duties,  as,  for  instance,  in  the  heart, 
the  kidneys,  and  the  liver.  But  the  formative  activity  of  Muscles  and  Nerves  is  so 
closely  dependent,  as  already  several  times  pointed  out,  upon  the  active  exercise 
of  their  functional  powers,  that  atrophy  is  certain  to  supervene  if  this  be  inter- 
rupted ;  and  this  atrophy  may  or  may  not  present  itself  under  the  form  of  fatty  de- 
generation ;  a  shrinkage  of  the  parts,  concurrently  with  the  production  of  an  in- 
creased amount  of  fat  in  them,  being  perhaps  the  mode  in  which  it  most  frequently 
takes  place.  Atrophy  of  one  part,  moreover,  may  be  dependent  upon  atrophy 
or  imperfect  functional  activity  of  another,  if  the  two  be  so  related  in  their 
normal  functions  that  a  decline  of  one  involves  a  corresponding  decline  in  the 
other.  Thus  if  a  motor  nerve  be  paralyzed,  the  muscles  which  it  habitually 
calls  into  action  will  be  atrophied ;  and  this  will  equally  happen,  whether  the 
want  of  motor  power  depend  upon  a  deficient  production  of  it  in  the  nervous 
centres,  or  upon  an  interruption  to  its  conduction  through  the  trunks.3  On  the 
other  hand,  if  the  muscles  of  a  part  undergo  degeneration  from  want  of  use  (as 
in  disease  of  the  hip-joint),  the  nerves  which  supply  them  also  suffer.  The 
same  is  the  case  in  regard  to  the  nerves  and  organs  of  sense;  for  atrophy  of  the 

1  "  Medico-Chirurgical  Transactions,"  vol.  xx. 

2  The  Author  has  for  some  time  had  under  his  observation  a  case  in  which  three  males 
of  a  family  have  progressively  become  affected,  between  the  ages  of  3  and  5  years,  with 
fatty  degeneration  of  the  muscles,  which  has  proceeded  in  the  most  advanced  case  to  the 
almost  complete  obliteration  of  their  normal  structure.     This  change  had  been  considered 
by  many  eminent  practitioners  to  be  idiopathic,  that  is,  to  have  its  primary  origin  in  the 
muscular  tissue ;  and  the  measures  which  had  been  employed  to  arrest  it  had  been  of  no 
avail  whatever.     It  was  a  strong  argument,  however,  against  such  a  view  of  the  case,  that, 
in  the  heart  of  the  eldest  son,  who  died  of  fever  at  the  age  of  16,  no  fatty  degeneration  could 
be  discovered  ;  and  on  making  inquiry  into  the  history  of  the  parents  and  their  families, 
ample  evidence  was  discovered  for  the  belief  that  the  disease  was  dependent  upon  want 
of  functional  power  in  the  nervous  centres.     Acting  on  this  view,  it  was  recommended  that 
the  muscular  system  should  be  kept  as  much  as  possible  in  a  state  of  active  exercise,  and 
that  a  weak  galvanic  current  should  be  frequently  transmitted  through  the  limbs  from  the 
spine.     This  treatment  has  proved  so  far  successful,  that  the  progress  of  the  disease  appears 
to  have  been  arrested  in  the  most  advanced  case ,  whilst  a  decided  improvement  has  taken 
place  in  the  condition  of  a  younger  child,  who  was  previously  passing  rapidly  into  a  state 
resembling  that  of  his  elder  brothers. 


560  OF    NUTRITION. 

eye  will  occasion  atrophy  of  the  optic  nerve,  and  destruction  of  the  optic  gan- 
glia will  induce  atrophy  of  the  eyes  and  optic  nerves.  Even  the  bones  of  a 
limb  will  suffer,  in  cases  of  atrophy  of  the  muscles  consequent  upon  disuse;  for 
in  the  case  already  cited  (§  313)  from  Dr.  J.  Reid,  the  bones  of  the  quiescent 
limb  only  weighed  81  grains,  whilst  those  of  the  exercised  limb  weighed  89 
grains. — It  is  an  important  fact,  which  was  first  pointed  out  by  Mr.  Paget,1  that 
when  fatty  degeneration  is  commencing  in  any  tissue  which  is  characterized  by 
the  persistence  of  its  nuclei,  it  is  in  the  nuclei  that  the  first  alterations  are 
seen ;  for  they  become  pale  and  indistinct,  and  gradually  disappear  altogether, 
almost  before  any  other  change  is  discernible  in  the  contents  of  the  cells  or  tubes 
to  which  they  appertain ;  but  in  atrophy  from  mere  decrease,  this  disappearance 
of  the  nuclei  does  not  occur. 

599.  Reparative  Process. — The  nutritive  operations  take  place,  with  extra- 
ordinary energy  and  rapidity,  in  the  process  of  Reparation;  by  which  losses 
of  substance,  occasioned  by  injury  or  disease,  are  made  good.  In  its  most 
perfect  form,  this  process  is  exactly  analogous  to  that  of  the  first  development  of 
the  corresponding  parts ;  and  its  results  are  as  complete  in  the  one  case  as  in 
the  otKer.  In  fact,  among  the  lowest  tribes  of  Animals,  we  find  these  two 
conditions  blended,  as  it  were,  together;  for  the  process  of  reparation  may  be 
carried  in  them  to  such  an  extent  as  to  regenerate  the  whole  organism  from  a 
very  small  portion  of  it.  In  the  Hydra  or  Fresh-water  Polype,  there  would 
seem  to  be  scarcely  any  limit  to  this  power ;  for  even  if  the  body  of  the  ani- 
mal be  minced  into  small  fragments,  every  one  of  these  can  produce  a  new  and 
perfect  being.  In  this  manner,  no  less  than  forty  have  been  artificially  gene- 
rated from  a  single  individual. — In  ascending  the  Animal  scale,  we  find  this 
reparative  power  less  conspicuous,  because  limited  in  its  exercise  to  particular 
tissues  and  to  comparatively  insignificant  parts  of  the  body;  and  in  Man,  as  in 
other  warm-blooded  Vertebrata,  the  regenerative  power  is  for  the  most  part 
restricted  in  its  exercise,  as  Mr.  Paget  has  pointed  out,2  to  three  classes  of 
parts; — namely,  (1.)  "Those  which  are  formed  entirely  by  nutritive  repetition, 
like  the  blood  and  epithelia,  their  germs  being  continually  generated  de  novo 
in  the  ordinary  condition  of  the  body;  (2.)  Those  which  are  of  lowest  organi- 
zation, and  (what  seems  of  more  importance)  of  lowest  chemical  character,  as 
the  gelatinous  tissues,  the  areolar  and  tendinous,  and  the  bones;  (3.)  Those 
which  are  inserted  in  other  tissues  not  as  essential  to  their  structure,  but  as 
accessories,  as  connecting  or  incorporating  them  with  the  other  structures  of 
vegetative  or  animal  life,  such  as  nerve-fibres  or  bloodvessels.  With  these 
exceptions,  injuries  or  losses  are  capable  of  no  more  than  repair  in  its  limited 
sense ;  i.  e.,  in  the  place  of  what  is  lost,  some  lowly  organized  tissue  is  formed, 
which  fills  up  the  breach,  and  suffices  for  the  maintenance  of  a  less  perfect 
life." — Yet,  even  thus  restricted,  the  operations  of  this  power  are  frequently 
most  remarkable ;  and  are  in  no  instance,  perhaps,  more  strikingly  displayed, 
than  in  the  re-formation  and  remodelling  of  an  entire  bone  when  the  original  one 
has  been  destroyed  by  disease.  That  this  power  is  intimately  related  to  that  by 
which  the  organism  is  normally  built  up  and  maintained,  is  evident,  not 
merely  from  the  peculiar  mode  in  which  it  is  exercised — its  tendency  being 
always  to  reproduce  each  part  in  the  form  and  structure  characteristic  of  it  at 
the  particular  period  of  life,  and  not  according  to  its  embryonic  type — but  also 
from  the  fact  that  it  is  more  effectual  in  the  state  of  growth  than  in  the  adult 
condition,  and  that  it  can  do  far  more  in  the  embryonic  state,  when  develop- 
ment as  well  as  growth  is  taking  place,  than  after  the  developmental  process 

1  "Lectures  on  Nutrition,"  &c.,  in  "Medical  Gazette,"  1847,  vol.  xl.  pp.  145,  146. 

2  "Lectures  on  Reproduction  and  Repair,"  in  "Medical  Gazette,"  1840,  vol.  xliii,  p. 
1022. 


REPARATIVE   PROCESS.  561 

has  ceased.  In  fact,  as  Mr.  Paget  has  pointed  out  (loc.  cit.),  its  amount  at 
different  periods  of  existence,  as  in  different  classes  of  animals,  seems  to  bear 
an  inverse  ratio  to  the  degree  of  development  which  has  already  taken  place. 
Thus  it  is  well  known  to  every  Practitioner  how  much  more  readily  and  per- 
fectly the  lesions  resulting  from  accident  or  disease  are  repaired  in  childhood 
and  youth,  than  they  are  after  the  attainment  of  the  adult  state.  And  there 
is  evidence  that  during  embryonic  life,  the  regeneration  of  lost  parts  may  take 
place  in  a  degree  to  which  we  have  scarcely  any  parallel  after  birth ;  for  Prof. 
Simpson  has  brought  together  numerous  cases,  in  which,  after  "  spontaneous 
amputation' '  of  the  limbs  of  a  foetus,  occurring  at  an  early  period  of  gestation, 
there  has  obviously  been  an  imperfect  attempt  at  the  re-formation  of  the  ampu- 
tated part  from  the  stump  •*•  and  it  seems  probable,  from  the  history  of  normal 
development,  that  in  the  cases  in  which  perfect  hands  and  feet  have  been 
present  without  the  corresponding  limbs,  these  hands  and  feet  have  been  second- 
ary productions  from  the  stumps  of  amputated  limbs,  since  any  original  defect 
of  development  would  have  affected  the  hands  and  feet  rather  than  the  arms 
and  legs.  There  are  occasional  instances,  however,  in  which  this  regenerative 
power  has  been  prolonged  to  an  unusually  late  period ;  thus  an  instance  is 
recorded,  on  authority  that  can  scarcely  be  doubted,  of  the  twice  repeated  re- 
production of  a  supernumerary  thumb,  after  it  had  been  twice  completely 
removed  ;3  and  the  Author  has  been  assured  by  a  very  intelligent  Surgeon,  that 
he  was  cognizant  of  a  case  in  which  the  whole  of  one  ramus  of  the  lower  jaw 
had  been  lost  by  disease  in  a  young  girl,  yet  the  jaw  had  been  completely 
regenerated,  and  teeth  were  developed  and  occupied  their  normal  situations  in  it.3 

600.  It  has  been  a  general  opinion  among  British  surgeons  (founded  upon 
what  they  believe,  but  erroneously,  to  have  been  the  doctrine  of  Hunter),  that 
Inflammation  is  essential  to  the  process  of  Reparation.     There  is  no  doubt  that, 
as  usually  conducted,  the  healing  of  wounds  is  attended  by  a  greater  or  less 
degree  of  Inflammation ;  but  it  does  not  thence  follow  that  this  morbid  condi- 
tion is  essential  to  the  renewal  of  the  healthy  state ;  and  in  fact  it  can  be  shown 
that,  in  the  majority  of  cases,  the  occurrence  of  Inflammation  is  injurious  rather 
than  beneficial.     It  was  by  Dr.  Macartney  that  the  first  clear  enunciation  of  this 
important  truth  was  made ;  and  his  conclusions,  founded  upon  a  philosophical 
comparative  survey  of  the  operations  of  Reparation  and  Inflammation,  as  per- 
formed in  the  different  classes  of  animals — namely,  "that  the  powers  of  repara- 
tion and  reproduction  are  in  proportion  to  the  indisposition  or  incapacity  for 
inflammation  ; — that  inflammation  is  so  far  from  being  necessary  to  the  repara- 
tion of  parts,  that,  in  proportion  as  it  exists,  the  latter  is  impeded,  retarded,  or 
prevented ; — that,  when  inflammation   does  not  exist,  the  reparative  power  is 
equal  to  the  original  tendency  to  produce  and  maintain  organic  form  and  struc- 
ture;— and  that  it  then  becomes  a  natural  function,  like  the  growth  of  the 
individual,  or  the  reproduction  of  the  species"4 — may  be  regarded  as  substan- 
tially correct,  although  requiring  some  modification  in  particular  cases. 

601.  The  simplest  of  all  the  methods  of  healing  of  an  open  wound   is  that 
which  is  termed  by  Dr.  Macartney  "  immediate  union."     It  is  often  seen  in 
the  case  of  small  incised  wounds,  such  as  cuts  of  the  fingers,  or  the  incision 

1  These  cases  were  brought  by  Prof.  Simpson  before  the  Physiological  Section  of  the 
British  Association  at  its  meeting  in  Edinburgh,  Aug.  1850.^  The  Author,  having  had 
the  opportunity  of  examining  two  living  examples,  as  well  ay 'Prof.  Simpson's  prepara- 
tions, is  perfectly  satisfied  as  to  the  fact. 

2  See  Mr.  White's  Treatise  on  the  "  Regeneration  of  Animal  and  Vegetable  Substances" 
(1785),  p.  1C. 

3  For  a  sketch  of  the  Regenerative  Process  as  performed  in  different  tribes  of  Animals, 
see  "  Princ.  of  Phys.,  Gen.  and  Comp.,"  $g  645  and  646,  Am.  Ed.,  and  the  account  of 
each  class  in  CHAP.  vii. 

4  Dr.  Macartney's  "Treatise  on  Inflammation,"  p.  7. 

36 


562  OF   NUTRITION. 

made  in  venesection,  in  which  the  two  edges  can  be  brought  into  close  approxi- 
mation, so  that  they  grow  together  without  any  connecting  medium  of  blood  or 
lymph;  but  it  sometimes  occurs  in  larger  ones,1  and  as  it  is  the  best  imaginable 
process,  the  surgeon  ought  to  favor  it  as  much  as  possible,  by  procuring  the 
most  exact  coaptation  of  the  wounded  parts,  and  by  repressing  any  tendency  to 
inflammation,  which  will  interfere  with  it.  This  is  the  mode  of  union  which 
was  spoken  of  by  John  Hunter  as  "healing  by  the  first  intention."  He  sup- 
posed that  the  union  takes  place  through  the  medium  of  the  blood  intervening 
between  the  lips  of  the  wound,  which  undergoes  organization  into  a  connecting 
tissue ;  but  it  is  now  certain  that  although  blood  may  become  organized,  espe- 
cially when  effused  into  a  wound  secluded  from  the  air,  yet  that  its  intervention 
rather  opposes  than  favors  healing  by  immediate  union. 

602.  That  which  is  commonly  known  amongst  British  Surgeons  as  "healing 
by  the  first  intention,"  is  that  which  was  designated  by  Hunter  as  "  union  by 
adhesion"  or  by  "adhesive  inflammation."     This  process  takes  place  in  the  case 
of  incised  wounds,  of  which  the  edges  are  not  brought  into  perfect  coaptation,  or 
in  which  some  inflammatory  action  is  present,  which  gives  rise  to  the  effusion  of 
plastic  lymph.     In  either  case,  the  connection  is  finally  re-established  by  the 
organization  of  the  lymph,  into  which  vessels  pass  from  both  surfaces ;  but  the 
intervention  of  this  bond  is  manifested  in  the  persistence  of  the  cicatrix,  which 
is  quite  distinguishable  by  its  peculiar  appearance  from  the  surrounding  tissue. 
A  very  good  example  of  this  process,  as  it  takes  place  under  favorable  circum- 
stances, is  presented  after  operations  for  harelip;   the  wound  left  by  which, 
however,    may   partly   heal   by   "immediate   union."      Even    the   moderate 
effusion  of  lymph,  to  a  degree  that  is  altogether  salutary,  cannot  be  regarded  as 
alone  sufficing,  under  such  circumstances,  to  constitute  Inflammation.     It  is 
well  known  that  if  a  slight  wound,  which  is  thus  healing,  be  provoked  to  an 
increased  degree  of  inflammation,  its  progress  is  interrupted ;  and  all  the  means 
which  the  Surgeon  employs  to  promote  union,  are  such  as  tend  to  prevent  the 
accession  of  this  state. — The  only  case  in  which  the  concurrence  of  Inflamma- 
tion can  be  regarded  as  salutary,  is  that  in  which  there  is  a  deficiency  of  Fibrin 
in  the  blood,  causing  a  deficient  organizability  of  the  lymph.     It  has  been  seen 
that  the  amount  of  fibrin  is  rapidly  increased  by  inflammation  :  and  the  Surgeon 
well  knows  that  a  wound  with  pale  flabby  edges,  in  a  depressed  state  of  the 
system,  will  not  heal,  until  some  degree  of  Inflammation  has  commenced.     But 
when  the  inflammatory  state  has  developed  itself,  in  however  trifling  a  degree, 
there  is  always  a  risk  of  its  proceeding  further,  and  occasioning  a  degeneration 
of  the  plastic  material,  so  that  the  formation  of  pus-cells  and  the  effusion  of 
purulent  fluid  take  place,  instead  of  the  development  of  uniting  tissue. 

603.  The  reparation  of  wounds,  in  which  there  has  been  so  great  a  loss  of 
substance  that  neither  immediate  union  nor  adhesion  by  a  thin  layer  of  coagula- 
ble  lymph  can  take  place,  is  accomplished  by  the  gradual  development  of  new 
tissue  from  the  "nucleated  blastema"  with  which  the  cavity  is  first  filled.     But 
this  may  take  place  in  different  modes,  according  to  the  degree  in  which  it  is 
disturbed  by  the  Inflammatory  process;  and  it  should  be  the  great  object  of  the 
Surgeon  to  procure  the  most  favorable  method  of  its  performance.     It  has  been 
shown  by  Mr.  Paget,.that  the  mode  in  which  the  process  of  filling  up  is  accom- 
plished differs  essentially  according  as  the  wound  is  subcutaneous,  or  is  exposed 
to  air.     In  the  former  *€ase,  the  nucleated  blastema  is  gradually  developed  into 
fibrous  tissues  (§  224)  without  any  loss,  and  usually  with  freedom  from  local 

1  Mr.  Paget  mentions  a  case  of  extirpation  of  a  mammary  tumor,  in  which  the  greater 
part  of  the  wound  was  found  to  have  healed  after  this  fashion;  the  skin  and  fascia  having 
so  firmly  adhered,  that  no  indication  existed  of  their  previous  detachment ;  and  no  effusion 
of  coagulable  lymph,  or  production  of  a  connecting  tissue,  being  detectible  by  microscopic 
examination. 


REPARATIVE   PROCESS.  563 

inflammation  (beyond  what  may  have  been  requisite  for  the  production  of  the 
plastic  fluid),  as  well  as  from  constitutional  irritation.  In  the  latter  case,  the 
nucleated  blastema  is  developed  into  cells;  and  those  on  its  exposed  surface  are 
unable,  either  from  degeneration  or  from  imperfect  development,  to  pass  on  to 
any  higher  form  of  organization,  but  take  on  the  characters  of  pus-cells,  and 
are  only  fit  to  be  cast  off.  Hence  there  is  a  continual  loss  of  plastic  material, 
the  amount  of  which,  in  the  case  of  an  extensive  suppurating  sore,  forms  a  most 
serious  drain  upon  the  system;  whilst,  at  the  same  time,  the  local  inflammation 
gives  rise  to  more  or  less  of  constitutional  disturbance,  and  the  formation  of 
new  tissue  is  by  no  means  so  perfect  as  in  the  preceding  case.  In  cold-blooded 
animals,  however,  the  contact  of  air  does  not  produce  this  disturbance ;  and  we 
see  wounds  with  extensive  loss  of  substance  gradually  filled  up  in  them  by  the 
development  of  new  tissue,  without  any  suppuration  or  other  waste  of  material, 
very  much  as  in  the  subcutaneous  wounds  of  warm-blooded  animals.  This 
method  of  healing,  which  has  been  termed  by  Dr.  Macartney  the  "modelling 
process/'  is  nothing  else  than  healing  by  granulations  under  the  most  favorable 
circumstances;  and  to  procure  this  should  be  the  endeavor  of  the  Surgeon,  who 
too  frequently  considers  suppurative  granulation  as  the  only  means  by  which  an 
open  wound  can  be  filled  up.  The  difference  between  the  two  modes  of  repara- 
tion is  often  one  of  life  and  death,  especially  in  the  case  of  large  burns  on  the 
trunk  in  children;  for  it  frequently  happens  that  the  patient  sinks  under  the 
great  constitutional  disturbance  occasioned  by  a  large  suppurating  surface, 
although  he  has  survived  the  immediate  shock  of  the  injury. — Now  the  means 
adopted  by  Nature  to  bring  this  about,  in  warm-blooded  animals,  is  the  forma- 
tion of  a  scab;  which  reduces  the  wound  more  nearly  to  the  condition  of  a  sub- 
cutaneous one,  so  that  the  reparative  growth  and  formation  of  new  tissue  take 
place  (under  favorable  circumstances)  without  any  suppuration,  and  with 
scarcely  any  irritation;  the  subsequent  cicatrix,  too,  being  much  more  like  the 
natural  parts,  than  are  any  scars  formed  in  wounds  that  remain  exposed  to  the 
air.  In  the  Human  subject,  however,  the  process  is  far  less  certain  than  it  is 
among  the  lower  animals,  owing  to  the  liability  to  inflammation  in  the  wounded 
part,  and  the  consequent  effusion  of  fluid,  which  produces  pain,  compresses  the 
wounded  surface,  or  forces  off  the  scab,  with  great  discomfort  to  the  patient, 
and  retardation  of  the  healing.  Small  wounds,  however,  in  persons  of  good 
habit  of  body,  and  in  parts  which  can  be  completely  kept  at  rest,  readily  heal 
in  this  manner;  and  large  wounds  have  been  known  to  close,  in  the  same  desira- 
ble mode,  beneath  a  clot  of  inspissated  blood.  In  fact,  among  "  uncivilized" 
nations,  whose  habits  of  life  are  favorable  to  health — their  bodies  being  con- 
tinually exposed  to  fresh  air,  their  food  wholesome  and  taken  in  moderation, 
and  their  drink  water  or  other  unstimulating  liquids — there  seems  to  be  as  great 
a  tendency  to  this  method  of  reparation  as  among  the  lower  animals;  and  the 
difficulty  of  procuring  it  among  the  members  of  "  civilized"  communities  is  owing, 
without  doubt,  to  the  unnatural  conditions  under  which  they  too  frequently 
live.  Seeing,  as  we  continually  do,  the  effects  of  foul  air,  of  habitual  excess  in 
diet,  and  of  the  constant  abuse  of  stimulants,  in  impairing  that  form  of  the 
reparative  process  which  must  be  regarded  as  the  least  favorable,  namely,  the 
closure  of  a  wound  by  suppurating  granulations,  it  is  very  easy  to  comprehend 
that,  to  induce  the  most  favorable  method,  the  most  perfect  freedom  from  all 
pernicious  agencies  should  be  required. 

604.  The  most  effectual  means  of  promoting  this  kind  of  Reparative  process, 
and  of  preventing  the  interference  of  Inflammation,  vary  according  to  the  nature 
of  the  injury.  The  exclusion  of  air  from  the  surface,  and  the  regulation  of  the 
temperature,  appear  the  two  points  of  chief  importance.  By  Dr.  Macartney, 
the  constant  application  of  moisture  is  also  insisted  on.1  He  states  that  the 

1  "Treatise  on  Inflammation,"  p.  178. 


564  OF   NUTRITION. 

immediate  effects  of  injuries,  especially  of  such  as  act  severely  upon  the 
sentient  extremities  of  the  nerves,  are  best  abated  by  the  action  of  "  steam  at  a 
high  but  comfortable  temperature,  the  influence  of  which  is  gently  stimulant, 
and  at  the  same  time  extremely  soothing."  After  the  pain  and  sense  of  injury 
have  passed  away,  the  steam,  at  a  lower  temperature,  may  be  continued;  and, 
according  to  Dr.  M.,  no  local  application  can  compete  with  this,  when  the  In- 
flammation is  of  an  active  character.  For  subsequently  restraining  this,  how- 
ever, so  as  to  promote  the  simple  reparative  process,  Water-dressing  will,  he 
considers,  answer  sufficiently  well;  its  principal  object  being  the  constant  pro- 
duction of  a  moderate  degree  of  Cold,  which  diminishes,  whilst  it  does  not  ex- 
tinguish, sensibility  and  vascular  action,  and  allows  the  Reparative  process  to 
be  carried  on  as  in  the  inferior  tribes  of  animals.  The  reduction  of  the  heat  in 
an  extreme  degree,  as  by  the  application  of  ice  or  iced  water,  is  not  here  called 
for,  and  would  be  positively  injurious;  since  it  not  only  renders  the  existence  of 
Inflammation  in  the  part  impossible,  but,  being  a  direct  sedative  to  all  vital 
actions,  suspends  also  the  process  of  restoration.  The  efficacy  of  Water-dressing 
in  injuries  of  the  severest  character,  and  in  those  which  are  most  likely  to  be 
attended  with  violent  Inflammation  (especially  wounds  of  the  large  joints)  has 
now  been  established  beyond  all  question;  and  its  employment  is  continually 
becoming  more  general.1 — Other  plans  have  been  proposed,  however,  which 
seem  in  particular  cases  to  be  equally  effectual.  To  Dr.  Greenhow,  of  New- 
castle, for  instance,  it  was  accidentally  suggested,  a  few  years  since,2  to  cover 
the  surface  of  recent  burns  with  a  liquefied  resinous  ointment,  so  as  to  form  an 
artificial  scab;  and  he  states  that  in  this  manner  suppuration  may  be  prevented, 
even  where  large  sloughs  are  formed;  the  hollow  being  gradually  filled  up  by 
new  tissue,  which  is  so  like  that  which  has  been  destroyed,  that  no  change  in 
the  surface  manifests  itself,  and  none  of  that  contraction,  which  ordinarily  oc- 
curs even  under  the  best  management,  subsequently  takes  place.  fA  plan  has, 
moreover,  been  proposed  for  preventing  suppuration,  and  promoting  reparation 
by  the  "  modelling"  process,  which  consists  in  the  application  of  warm  dry  air 
to  the  wounded  surface.  Although  the  experiments  yet  published  have  not 
been  entirely  satisfactory,  they  seem  to  show  that,  whilst  the  process  of  healing 
may  be  slower  under  treatment  of  this  kind,  it  is  attended  with  less  constitu- 
tional disturbance  than  is  often  unavoidable  in  the  ordinary  method;  and  that 
it  may  therefore  be  advantageously  put  in  practice  in  those  cases  in  which  the 
condition  of  the  patient  requires  every  precaution  against  such  an  additional 
burden — as  after  amputation  in  a  strumous  subject.3 

605.  When  the  process  of  healing  of  an  open  wound  by  Suppurative  Granu- 
lation is  attentively  watched,  it  is  seen  that  the  first  stage  is  the  formation  of  a 
"  glazing"  on  the  exposed  surface,  which  closely  resembles  the  buffy  coat  of  the 
blood,  being  composed  of  coagulated  fibrin  and  colorless  corpuscles;  in  this 
manner  a  sort  of  imperfect  epithelium  may  be  formed  within  half  an  hour  after 
the  surface  has  been  laid  bare.  The  increase  of  this  glazing  is  the  prelude  to 
the  formation  of  granulations ;  but  whilst  it  is  going  on,  there  is,  in  and  about 
the  wound,  an  appearance  of  complete  inaction,  a  sort  of  calm,  in  which  scarcely 
anything  appears  except  a  slight  oozing  of  serous  fluids  from  the  wound,  and 
which  continues  from  one  day  to  eight,  ten,  or  more,  according  to  the  nature 
and  extent  of  the  wounded  part,  and  the  general  condition  of  the  body.  "This 
calm,"  says  Mr.  Paget,  "maybe  the  brooding-time  for  either  good  or  evil; 
whilst  it  lasts,  the  mode  of  union  of  the  wound  will,  in  many  cases,  be  deter- 

1  See  an  account  of  the  result  of  this  treatment  by  Dr.  Gilchrist,  in  "  Brit,  and  For.  Med. 
Rev.,"  July,  1846,  p.  242. 

2  "Medical  Gazette,"  Oct.  13,  1838. 

8  See  M.  Jules  Guyot  "De  1'emploi  de  la  Chaleur  dans  le  Traitcment  des  Ulceres,  &c." 


EEPARATIVE   PROCESS.  565 

mined ;  the  healing  may  be  perfected,  or  a  slow  uncertain  process  of  repair  may 
be  but  just  begun  ;  and  the  mutual  influence  which  the  injury  and  the  patient's 
constitution  are  to  exercise  on  one  another  appears  to  be  manifested  more  often 
at  or  near  the  end  of  this  period,  than  at  any  other  time."  The  cessation  of 
this  period  of  calm,  and  the  active  commencement  of  the  reparative  operations, 
are  marked  by  the  restoration  of  the  flow  of  blood  in  the  vessels  of  the  wounded 
part;  but  the  current  is  not  altogether  normal,  being  slower  but  fuller  than 
natural,  so  that  on  the  whole  more  blood  than  usual  passes  through  the  capil- 
lary plexus.  This  increased  afflux  of  blood  is  followed  by  effusion  of  plastic 
material  in  increased  proportion;  and  it  is  from  this  effusion  that  the  granulat- 
ing process  properly  commences. — The  plastic  material  effused  upon  the  surface 
of  an  open  wound  is  first  developed  into  cells ;  and  these  cells,  in  the  deeper 
portions  of  the  effusions,  are  metamorphosed,  into  fibrous  tissue,  of  which  the 
substance  of  the  granulations  is  composed.  Those  which  are  formed  upon  the 
surface,  however,  are  converted  into  pus-cells  (§  614);  in  some  instances  (as 
Mr.  Paget  has  pointed  out)  by  degeneration  from  a  higher  development;  in  other 
cases  by  an  originally  imperfect  development :  and  thus  the  granulation  surface 
is  constantly  in  a  state  of  morbid  action,  and  a  large  proportion  of  the  plastic 
material  is  completely  wasted.  The  layer  of  pus,  however,  serves  as  a  sort  of 
epithelium  for  the  subjacent  granulation  tissue,  in  which  we  find  not  only  a  com- 
plete formation  of  cells,  but  a  commencement  of  the  metamorphosis  of  these 
cells  into  fibres,  before  bloodvessels  make  their  appearance  in  the  tissue.  These 
bloodvessels  are  formed  by  "out-growth"  from  the  subjacent  capillaries,  in  the 
mode  formerly  described  (§  295).  From  the  investigations  of  Mr.  Listen,  it 
appears  that  the  vessels  of  the  subjacent  tissue  are  much  enlarged,  and  assume 
a  varicose  character.  The  bright  red  color  of  the  granulations,  however,  does 
not  depend  on  their  vascularity  alone ;  for  the  cells  themselves,  especially  those 
most  recently  evolved,  are  of  nearly  as  deep  a  color  as  the  blood-corpuscles ;  and 
the  sanguineous  exudation  which  follows  even  the  slightest  touch  of  the  granu- 
lating surface,  does  not  proceed  from  blood  effused  from  the  newly-formed 
vessels  only;  for  the  red  fluid  shed  in  this  manner  contains,  besides  blood-disks, 
newly  developed  red  cells,  ruddy  cytoblasts,  pale  granules,  and  reddish  serum. 
It  is  a  common  property  of  animal  cytoblasts,  that  they  present  a  reddish  color 
on  their  first  formation,  when  in  contact  with  oxygen ;  but  this  hue  they  lose 
again,  whether  they  advance  to  perfect  development  and  become  integral  parts 
of  a  living  tissue,  or  die  and  degenerate. 

606.  The  process  of  Suppurative  Granulation,  then,  appears  to  differ  from 
the  process  of  granulation  as  it  takes  place  in  closed  wounds,  or  in  a  warm  moist 
atmosphere  (the  "modelling  process"  of  Dr.  Macartney),  essentially  in  this — 
that  a  large  part  of  the  exudation-corpuscles  deposited  on  the  wounded  surface 
degenerate  into  pus  in  the  former  case,  whilst  none  are  thus  wasted  in  the  latter : 
— but  that  the  existence  of  inflammation  occasions  a  more  copious  supply  of 
fibrin  in  the  former  case,  and  increases  its  tendency  to  become  organized;  the 
filling  up  of  a  wound  with  granulations  being  thus  a  much  more  rapid  process 
than  that  renewal  of  the  completely  formed  tissues  which  may  take  place  in 
the  absence  of  inflammation.     The  imperfect  character  of  the  granulation  struc- 
ture is  shown,  by  the  almost  complete  disappearance  of  it  after  the  wound  has 
closed  over.     The  portion  of  it  in  immediate  contact  with  the  subjacent  tissue, 
however,  appears  to  undergo  a  higher  organization ;  for  it  becomes  the  medium 
by  which  the  cicatrix  is  made  to  adhere  to  the  bottom  of  the  wound.     It  is  very 
liable  to  undergo  changes  which  end  in  its  disintegration;  as  is  evident  from  the 
known  tendency  to  re-opening,  in  wounds  that  have  been  closed  in  this  manner. 

607.  When  two  opposite  surfaces  of  granulations,  well  developed,  but  not 
yet  covered  with  cuticle,  are  brought  into  apposition,  they  have  a  tendency  to 
unite,  like  the  two  original  surfaces  of  an  incised  wound.     This  method  of  union, 


566  OF   NUTRITION. 

which  was  noticed  by  John  Hunter,  has  been  appropriately  termed  "secondary 
adhesion"  by  Mr.  Paget.  The  surgeon  may  frequently  have  recourse  to  it 
with  great  advantage,  when  primary  adhesion  is  impossible,  and  when  the  fill- 
ing up  of  the  wound  with  granulations  would  be  a  tedious  process,  and  very 
exhausting  to  the  patient.  In  applying  it  to  practice,  it  is  essential  to  success, 
first,  that  the  granulations  should  be  healthy,  not  inflamed  or  profusely  secret- 
ing, nor  degenerated  as  those  in  sinuses  commonly  are;  and  secondly,  that  the 
contact  between  them  should  be  gentle  but  maintained;  it  seems  desirable,  also, 
that  the  granulation  surfaces  should  be  as  much  as  possible  of  equal  develop- 
ment, and  alike  in  character.1 

3. — Abnormal  Forms  of  the  Nutritive  Process. 

608.  Under  the  preceding  head,  we  have  considered  the  chief  variations  in 
the  degree  of  activity  that  are  witnessed  in  the  ordinary  or  normal  conditions 
of  the  Nutritive  process — those  conditions,  namely,  in  which  the  products  are 
adapted,  by  their  similarity  of  character,  to  replace  those  which  have  been 
removed  by  disintegration.     But  we  have  now  to  consider  those  forms  of  this 
process — in  which  the  products  are  abnormal — being  different  from  the  tissues 
they  ought  to  replace.     We  shall  confine  ourselves  to  a  brief  examination  of  a 
few  of  some  of  the  most  important  of  these  states;  and  that  which  first  claims 
our  consideration,  on  account  of  the  frequency  of  its  occurrence  and  the  im- 
portance of  its  results,   is   Inflammation. — Although  Pathologists  have  been 
accustomed  to  look  for  the  "  proximate  cause"  of  the  phenomena  which  essen- 
tially constitute  the  Inflammatory  state,  or,  in  other  words,  for  the  first  de- 
parture from  the  normal  course  of  vital  action,  in  the  enlarged  or  contracted 
dimensions  of  the  bloodvessels  of  the  inflamed  part,  or  in  the  altered  rate  of 
movement  of  the  blood  through  it,  yet  it  may  now  be  safely  affirmed  that  these 
are  only  secondary  alterations,  depending  upon  an   original  and  essential  per- 
version of  that  normal  reaction  between  the  blood   and  the  tissues  which  con- 
stitutes the  proper  Nutritive  process.     This  perversion  manifests  itself  (1)  in 
a  diminution  in  the  formative  activity  of  the  tissues,  leading  to  their  degenera- 
tion and  death ;  (2)  in  a  tendency  to  augmented  production  of  the  plastic  com- 
ponents of  the  blood;  and  (3)  in  the  effusion  of  these  components,  either  in 
a  state  in  which  they  may  pass  into  a  low  form  of  organized  tissue,  or  in  such 
a  degraded  condition  that  they  are  altogether  unorganizable,  and  are  fit  only 
to  be  cast  out  of  the  body.     Each   of  these  phenomena  requires  a  separate 
examination,  both  as  to  its  causes  and  its  consequences. 

609.  Although  it  has  been  customary  to  speak  of  Inflammation  as  a  state 
of  "increased   action"  in  the  part  affected  —  of  which    increased  action  the 
augmentation  in  the  bulk  and  weight  of  an  inflamed  part,  and  in  the  quantity 
of  blood  which  passes  through  it,  together  with  its  higher  temperature  and 
more  acute  sensibility,  would  seem  to  furnish  sufficient  evidence — yet  all  these 
signs  are  found  to  be  deceptive  when  they  are  more  closely  examined ;  and  the 
conclusion  is  forced  upon  us,  that  the  vital  power  of  the  part  is  really  depressed 
rather  than  exalted.     For  the  increase  in  bulk  and  weight  is  not  due  to  such 
an  augmentation  of  its  proper  tissue  as  would  truly  constitute  Hypertrophy ; 
on  the  contrary,  even  in  the  slightest  forms  of  Inflammation  there  is  such  a 
diminution  in  the  rate  of  its  nutrition  as  really  constitutes  Atrophy ;  and  such 
augmentation  of  the  solid  mass  as  may  take  place,  is  produced  by  the  passage 
of  the  effused  fluid  into  an  organized  tissue  of  the  lowest  kind,  and  this  in 

1  On  the  whole  subject  of  the  Reparative  Processes,  see  the  admirable  Lectures  of  Mr. 
Paget,  in  the  "Medical  Gazette,"  1849 ;  from  which  many  of  the  foregoing  statements  and 
doctrines  are  adopted. 


ABNORMAL   FORMS   OF   THE    NUTRITIVE   PROCESS.  567 

virtue  rather  of  its  own  plasticity,  than  of  the  vital  force  which  it  derives  from 
the  tissues  which  it  infiltrates.  That  there  has  been  an  atrophy  rather  than  a 
hypertrophy  of  the  proper  fabric  of  the  part,  becomes  evident  enough  when 
the  inflammation  has  passed  away,  and  this  newly-formed  tissue  undergoes 
degeneration  and  absorption.  The  only  tissues  in  which  there  is  any  appearance 
of  increased  formation  during  the  inflammatory  state,  are  those  which  corre- 
spond in  their  low  type  of  organization  with  the  new  tissue  thus  generated ; 
namely,  the  areolar  and  other  simple  fibrous  tissues,  and  also  the  osseous,  of 
which  the  organized  basis  is  of  the  same  kind.  When  the  Inflammation  is 
more  severe,  the  tendency  to  degeneration  in  the  proper  tissues  of  the  part 
becomes  very  obvious ;  for  it  is  by  their  interstitial  decay  and  removal,  that  the 
cavity  of  an  abscess  is  formed ;  it  is  by  their  superficial  death  and  absorption 
or  solution  that  ulceration  takes  place ;  and  it  is  in  the  death  of  a  whole  mass 
at  once,  that  gangrene  consists. — That  a  diminution  in  the  formative  activity  of 
the  tissues  is  an  essential  characteristic  of  the  Inflammatory  state,  further 
appears  from  the  study  of  its  etiology;  for  whether  the  causes  to  which  the 
inflammatory  attack  may  be  traced  are  local  or  general,  acting  primarily  upon 
the  tissues  of  the  part,  or  first  affecting  the  blood,  their  operation  is  essentially 
the  same.  For  the  local  causes  are  all  obviously  such  as  tend  either  directly  to 
depress  the  vital  powers,  or  to  elevate  them  at  first,  and  then  to  depress  them 
by  exhaustion.  Of  the  former  kind  are  cold  and  mechanical  injury;  also  many 
chemical  agents,  whose  operation  tends  to  bring  back  the  living  tissues  to  the 
condition  of  inorganic  compounds.  Under  the  latter  category  are  to  be  ranked 
all  those  agencies  which  produce  over-exertion  of  the  functional  power  of  the 
part,  amongst  which  may  be  named  heat,  when  not  too  excessive  to  produce  a 
directly  destructive  effect.  Now  cold,  heat,  chemical  agents,  and  mechanical 
injury,  when  operating  in  sufficient  intensity,  at  once  kitt  the  part,  by  entirely 
destroying,  instead  of  merely  depressing,  its  vital  powers  ;  and  it  is  on  the 
borders  of  the  dead  part,  where  the  cause  has  acted  with  less  potency,  that  we 
find  the  inflammatory  state  subsequently  presenting  itself.  On  the  other  hand, 
there  can  be  no  doubt  that  many  inflammations  have  their  origin  in  morbid 
conditions  of  the  blood,  which,  without  any  other  cause  whatever,  may  deter- 
mine all  the  other  phenomena.  This  is  most  obvious  with  regard  to  those  of  a 
4 'specific"  kind;  but  it  is  also  probably  true  of  the  majority  of  the  so-called 
spontaneous  or  constitutional,  as  distinguished  from  traumatic  inflammations. 
We  seem,  indeed,  to  be  able  to  trace  a  regular  gradation  between  inflammatory 
attacks  which  are  entirely  traceable  to  the  introduction  of  a  poison  into  the 
blood,  and  those  which  result  from  causes  purely  local.  Under  the  first  head 
we  may  unquestionably  rank  such  inflammatory  diseases  as  are  producible  by 
inoculation,  the  eruptive  fevers  for  example ;'  and  scarcely  less  thoroughly 
demonstrated  are  the  cases  of  rheumatism  and  gout,  and  many  inflammations 
of  the  cutaneous  textures,  which,  when  occurring  in  the  chronic  form,  tend  to 
exhibit  a  regular  symmetry  (§  201).  In  all  such  cases,  the  local  affections  are 
the  external  signs  of  the  general  affection  of  the  blood,  just  as  are  the  inflam- 
mations produced  by  the  introduction  of  arsenic  or  of  other  irritant  poisons 
into  the  circulation;  and  they  may  in  fact  be  reasonably  attributed  to  the  im- 
pairment of  the  formative  activity  of  the  parts  upon  which  these  poisons  fix 
themselves,  in  virtue  of  their  "  elective  affinity"  (§  207),  just  as  the  peculiar 
functional  activity  of  the  nervous  centres  is  affected  by  narcotic  poisons.  And 
this  view  of  the  really  local  action  of  what  are  primarily  regarded  as  general  or 
constitutional  causes  of  inflammation,  is  confirmed  by  the  fact  that  the  locali- 
zation of  the  perverted  nutritive  condition  is  often  determined  (as  Dr.  W.  Budd 
and  Mr.  Paget  have  remarked)  by  a  previous  or  concurrent  weakening  or  de- 
pression of  the  vital  activity  of  the  part.  Thus,  a  part  which  has  been  the 
seat  of  former  disease  or  injury,  and  which  has  never  recovered  its  vigor  of 


568  OF   NUTRITION. 

nutrition,  is  always  more  liable  than  another  to  be  the  seat  of  local  manifesta- 
tion of  blood  disease;  it  is,  in  common  language,  the  "weak  part/'1  And  it 
frequently  needs  the  concurrent  operation  of  a  local  depressing  cause,  to  fix  and 
develop  the  action  of  the  constitutional  cause,  or  blood  disorder ;  thus,  a  rheu- 
matic or  gouty  diathesis  may  exist  for  some  time  (as  when,  to  use  a  common 
expression,  the  disease  is  "  flying  about"  the  patient),  and  yet  the  poison  may 
not  have  sufficient  potency  to  produce  an  attack  of  acute  inflammation,  until 
the  vitality  of  some  particular  organ  becomes  depressed  by  cold,  over-exertion, 
or  some  similar  influence,  which  would  not  have  itself  engendered  the  diseased 
action,  had  it  not  been  for  the  concurrence  of  the  morbid  condition  of  the 
blood. — Thus  we  seem  justified  in  concluding,  that,  whether  the  causes  of  In- 
flammation act  directly  upon  the  tissues  of  a  part,  or  whether  they  act  upon  it 
through  the  intermediation  of  the  blood,  their  effect  is  to  produce  a  depression 
in  its  vital  powers,  which  manifests  itself  in  a  deficient  formative  activity,  and 
in  an  increased  tendency  to  degeneration  ;  and  that  this  is  one  of  the  primary 
and  essential  conditions  of  Inflammation. 

610.  This  view  is  by  no  means  inconsistent  with  other  manifestations  of  In- 
flammation which  have  been  supposed  to  indicate  "  increased  action  ;"  and,  in 
fact,  it  is  in  such  striking  accordance  with  the  phenomena  presented  by  the 
movement  of  the  blood,  when  these  are  interpreted  by  the  principles  already 
laid  down,  as  to  afford  a  powerful  confirmation  to  both  doctrines.  The  usual 
condition  of  the  vessels  of  an  inflamed  part  is  one  of  dilatation  ;  and  this  may 
be  fairly  attributed  to  the  lowered  vitality  of  their  walls,  whereby  they  yield 
too  readily  to  the  distending  force  of  the  current  of  blood.  But  this  current 
moves  too  slowly ;  and  its  retardation  may  gradually  increase,  in  the  part  most 
intensely  inflamed,  to  the  point  of  complete  stagnation.  Now  this  altered  rate 
of  movement  cannot  be  attributed  to  any  general  cause  :  nor  can  it  be  accounted 
for  by  the  change  in  the  diameter  of  the  vessels  ;  for,  on  the  one  hand,  it  may 
occur  with  a  constricted  state  of  the  vessels,  whilst,  on  the  other,  in  the  vessels 
surrounding  the  inflamed  part,  which  partake  of  the  dilated  condition,  the  flow 
of  blood  is  so  far  from  being  retarded,  that  it  usually  takes  place  more  rapidly 
than  usual.  But  it  may  be  fairly  considered  as  the  result  of  the  lowered  or 
suspended  nutritive  activity  of  the  part,  which  will  tend  to  retard  or  entirely 
check  the  motion  of  blood  in  the  systemic  capillaries,  just  as  the  want  of  aera- 
tion retards  or  checks  the  pulmonary  circulation  (§  527).  It  is  quite  true  that 
a  larger  amount  of  blood  passes  through  a  limb,  of  which  some  part  is  in  a  state 
of  active  inflammation,  than  passes  through  the  corresponding  sound  limb; 
but  this  is  far  from  indicating  "  increased  action"  in  the  inflamed  part,  being 
dependent  upon  the  augmented  flow  of  blood  through  the  tissues  which  sur- 
round it ;  and  if  the  whole  of  a  limb  be  in  a  state  of  inflammation  passing  on 
to  gangrene  (as  occurs  when  a  "  frost-bitten"  limb  has  been  incautiously  warmed) 
the  amount  of  blood  which  passes  through  it  is  diminished.  It  would  be  just 
as  erroneous  to  assume  the  elevated  temperature  of  an  inflamed  part  as  a  sign 
of  "  increased  action"  in  it;  for  this  elevation  is  no  doubt  attributable  in  part 

1  A  patient  under  Dr.  W.  Budd's  care  had  Smallpox  soon  after  a  fall  on  the  nates ;  the 
pustules  were  thinly  scattered  everywhere,  except  in  the  seat  of  former  injury,  and  on  this 
they  were  crowded  as  thickly  as  possible.  So  a  man  who  was  under  Mr.  Paget's  care 
with  chronic  inflammation  of  the  synovial  membrane  of  the  knee-joint,  and  general 
swelling  about  it,  having  been  attacked  with  Measles,  the  eruption  over  the  diseased  knee 
was  a  diffused  bright  scarlet  rash.  So  Impetigo  appears  about  blows  and  scratches  in 
unhealthy  children,  and  Erysipelas  first  attacks  the  seat  of  local  injury  in  men  with 
unhealthy  blood.  Perhaps  as  good  an  example  as  any  is  afforded  by  the  uniform  limita- 
tion of  the  inflammation  consequent  upon  the  introduction  of  Vaccine  matter  into  the 
blood,  to  the  spots  in  which  the  puncture  was  made;  notwithstanding  that  the  whole  mass 
of  blood  is  affected  by  it,  as  is  shown  by  its  incapacity  for  subsequently  developing  the 
poison  of  smallpox. 


ABNORMAL   FORMS   OF   NUTRITIVE   PROCESS. — INFLAMMATION.    569 

to  the  augmented  flow  of  blood  through  the  surrounding  vessels ;  and,  so  far  as 
it  depends  upon  local  changes,  it  obviously  indicates  a  more  rapid  disintegration 
of  tissue,  rather  than  a  more  energetic  production  of  it ;  since  it  is  in  the  former 
state  rather  than  in  the  latter,  that  the  conditions  of  the  development  of  heat 
(on  the  chemical  theory)  are  supplied,  as  we  see  that  the  heat  of  a  muscle  is 
the  greatest  when  it  is  being  disintegrated  by  active  exercise  (§  330),  not  when 
it  is  being  repaired  by  the  formation  of  new  tissue  in  the  intervals  of  repose. 
But,  as  Mr.  Paget  justly  remarks,  "  this  phenomenon  is  involved  in  the  same 
difficulty  as  are  all  those  that  concern  the  local  variations  of  temperature  in  the 
body ;  difficulties  which  the  doctrines  of  Liebig,  however  good  for  the  general 
production  of  heat,  are  quite  unable  to  explain."  (See  CHAP,  xm.) — And 
lastly,  with  regard  to  the  unusual  tenderness  of  inflamed  parts,  this  is  obviously 
due  to  such  a  combination  of  causes,  none  of  which  can  be  legitimately  held  to 
indicate  an  increase  of  its  proper  vital  activity,  that  nothing  can  be  rested  on 
this  alone ;  especially  as  we  see  an  augmentation  in  the  susceptibility  of  the 
sentient  nerves,  under  many  circumstances  (as  in  hysterical  disorders),  in  which, 
far  from  an  augmented  there  is  obviously  a  diminished  activity  in  the  parts 
from  which  they  spring. — That  neither  an  alteration  in  the  circulation  of  a  part, 
nor  a  departure  from  the  normal  condition  of  its  nervous  supply,  can  be  regarded 
as  one  of  the  essential  phenomena  of  inflammation,  is  obvious  from  this,  that 
the  most  important  phenomena  of  inflammation  may  present  themselves,  as 
results  of  injury  or  disease,  in  parts  that  have  neither  bloodvessels  nor  nerves : 
this  is  seen  in  the  deposition  of  lymph  in  the  cornea,  in  the  ulceration  of  the 
cornea  and  of  articular  cartilages,  and  in  other  morbid  actions  in  these  parts, 
which,  if  ever  they  are  vascular,  become  so  only  after  the  effusion  of  lymph  in 
them,  the  new  vessels  being  formed  in  this  lymph,  and  not  in  the  tissues  them- 
selves. Here  it  is  obvious  that  the  whole  change  consists  in  a  perversion  of  the 
nutritive  actions  which  the  tissues  ought  to  carry  on,  at  the  expense  of  the  ma- 
terials which  they  draw  from  the  blood  of  the  surrounding  vessels  (§§  253, 254). 

611.  Of  the  alterations  in  the  condition  of  the  Blood  in  Inflammation,  an 
account  has  already  been  given  (§§  171-177) ;  and  it  is  here  only  necessary  to 
recapitulate  them.     The  most  characteristic  is  the  augmentation  either  of  the 
organizable  or  plastic  fibrin,  or  of  the  organized  colorless  corpuscles;  the  in- 
creased production  of  these  two  components  seeming  to  bear  in  some  degree  a 
relation  of  reciprocity,  the  one  to  the  other.     The  increase  of  Fibrin  may  be 
considered  as  the  alteration  most  characteristic  of  a  previously  healthy  and 
vigorous  state  of  the  system;  and  it  is  in  the  inflammations  which  occur  in  such 
subjects,  that  the  effusions  are  most  strongly  disposed  to  become  organized,  and 
show  the  least  tendency  to  undergo  degenerative  changes.     On  the  other  hand, 
the  increase  of  the  Corpuscular  element  seems  to  occur  in  cachectic  or  otherwise 
unhealthy  individuals;  and  the  inflammatory  effusions,  which  partake  of  the 
same  character,  are  far  less  plastic  originally,  and  are  extremely  prone  to  under- 
go degeneration,  either  at  the  time  of  their  effusion  or  subsequently.     With 
this  increase  in  the  proportion  of  fibrin  and  colorless  corpuscles,  separately  or 
in  combination,  there  is  a  diminution  in  the  proportion  of  the  red  corpuscles, 
albumen,  and  salts  of  the  blood.     None  of  these  changes,  however,  can   be 
legitimately  regarded  as  originally  or  essentially  characteristic  of  the  inflamma- 
tory condition ;   they  are,  in  fact,  to  be  looked-on  rather   as  the  results  of  its 
establishment,  constituting  that  series  of  alterations  in  the  circulating  fluid, 
which  is  of  parallel  order  to  that  which  occurs  in  the  solid  tissues  wherein  the 
inflammatory  action  has  been  set  up. 

612.  The  Inflammatory  state  is  further  characterized  by  the  effusion  of  certain 
of  the  components  of  the  Blood,  upon  the  surface,  or  into  the  substance,  of  the 
inflamed  tissues. — The  effusion  of  pure  serum  cannot  be  regarded  as  character- 
istic of  inflammation ;   since  it  may  take  place  as  a  mere  result  of  congestion, 


570  OF    NUTRITION. 

especially  when  this  congestion  is  due  to  an  obstruction  to  the  return  of  the 
blood ;  whilst,  again,  it  may  be  due  to  an  altered  condition  of  the  albuminous 
constituent  of  the  blood,  which  favors  its  transudation  (§  167).  The  so-called 
serous  effusions  which  are  poured  forth  in  inflammation  do  in  reality  contain 
fibrin  in  solution ;  but  this  fibrin  may  not  manifest  its  presence  by  spontaneous 
coagulation,  until  its  passage  into  the  solid  state  is  favored  by  some  extraneous 
influence  (§  26).  The  presence  of  fibrin  in  such  an  effusion,  however,  is  not 
in  itself  a  sufficient  proof  of  the  existence  of  inflammation ;  for  it  has  been  shown 
by  the  experiments  of  Mr.  Robinson,1  that  when  the  obstruction  to  the  return 
of  blood  by  the  veins  is  so  great  as  to  occasion  an  excessive  pressure  within  the 
capillaries,  the  fluid  which  transudes  may  contain  enough  fibrin  to  render  it 
spontaneously  coagulable. — The  form  of  exudation  which  is  most  characteristic 
of  Inflammation  is  that  which  is  known  as  coagulable  lymph;  it  is  much  to  be 
desired,  however,  that  some  other  designation  should  be  applied  to  it,  since  the 
term  "lymph"  can  only  be  appropriately  employed  for  the  fluid  contents  of  the 
lymphatic  vessels.  The  peculiar  characteristic  of  this  inflammatory  exudation 
is  its  capability  of  spontaneously  passing  into  the  condition  of  an  organized 
tissue,  either  fibrous  or  cellular,  or  a  mixture  of  both ;  and  of  thus  forming 
"  false  membranes"  on  inflamed  surfaces,  or  solidifying  the  inflamed  part  by  the 
interstitial  production  of  similar  lowly-organized  textures.  Although  it  has 
been  too  much  the  habit  of  Pathologists  to  speak  of  "coagulable"  or  "plastic 
lymph"  as  if  it  were  always  one  and  the  same  thing,  yet  it  really  presents 
various  gradations  of  character,  which  are  manifested  in  its  different  degrees  of 
organizability,  and  in  the  diverse  nature  of  the  tissues  developed  from  it;  and, 
as  Mr.  Paget  has  pointed  out,3  there  are  two  typical  forms,  the  fibrinous,  and 
the  corpuscular ,  between  which  the  others  are  intermediate.  The  former  coagu- 
lates into  a  fibrous  clot,  resembling  that  of  healthy  blood,  but  usually  showing  a 
more  distinct  fibrillation.  The  latter  (the  "croupous"  exudation  of  Rokitansky) 
is  characterized  by  the  want  of  any  proper  coagulation,  the  fibrous  clot  being 
replaced  by  an  aggregation  of  cells,  which  in  their  first  appearance  resemble 
very  nearly  the  primordial  condition  of  the  corpuscles  of  the  fluids  of  the  ab- 
sorbent vessels,  and  the  colorless  corpuscles  of  the  blood.  It  is  seldom,  however, 
that  either  of  these  typical  forms  of  lymph  presents  itself  in  a  state  of  complete 
isolation  from  the  other;  they  are  much  more  commonly  blended  in  various 
proportions,  so  that  one  or  the  other  predominates ;  and  it  is  mainly  upon  the 
preponderance  of  fibrin,  that  the  "plasticity"  of  the  exudation  (or  its  capacity 
for  organization)  depends;  whilst  according  to  the  preponderance  of  corpuscles 
will  be  its  tendency  to  degeneration.  Thus  the  exudation  of  fibrinous  lymph  is 
the  symbol  of  the  "adhesive"  inflammation;  whilst  that  of  the  "corpuscular" 
is  similarly  characteristic  of  the  "  suppurative"  inflammation.  It  is  obviously 
of  great  consequence  to  ascertain  the  conditions  which  determine  the  production 
of  one  or  other  of  these  states;  and  these,  as  Mr.  Paget  has  pointed  out  (loc. 
cit.),  may  be  considered  under  three  heads — (1)  the  previous  state  of  the  blood, 
(2)  the  seat  of  the  inflammation,  and  (3)  the  degree  and  character  of  the  in- 
flammation. 

613.  The  condition  of  the  blood,  as  determining  that  of  the  lymph,  has  been 
carefully  studied  by  Rokitansky;  who  has  shown  that  the  characters  of  inflam- 
matory deposits  in  different  diatheses  correspond  very  generally  and  closely  with 
those  of  the  coagula  found  in  the  heart  and  pulmonary  vessels  after  death.  The 
results  of  Mr.  Paget' s  experiments  on  the  same  subject  have  been  already  cited 
(§  196).  And  clinical  observation  fully  confirms  this  doctrine  by  evidence  of 
another  kind;  that,  namely,  which  is  afforded  by  the  different  course  of  the  same 

1  "  Medico-Chirurgical  Transactions,"  vol.  xxvi.  p.  51. 

2  "Lectures  on  Inflammation,"  in  "  Medical  Gazette,"  1850,  vol.  xlv.  p.  1012. 


ABNORMAL   FORMS    OF    NUTRITIVE   PROCESS. INFLAMMATION.     571 

specific  diseases,  in  different  individuals,  according  to  the  previously  healthy  or 
abnormal  condition  of  their  blood.  There  can  be  no  doubt  that  a  very  large 
proportion  of  what  are  called  "  unhealthy  inflammations/7  especially  those  of 
the  erysipelatous  type,  are  to  be  regarded  as  owing  their  peculiarity  to  a  defi- 
ciency in  the  due  elaboration  of  the  fibrin,  and  to  the  low  vitality  of  the  cellular 
components  of  the  blood,  both  of  which  conditions  seem  to  be  favored  by  the 
presence  of  those  decomposing  matters  whose  accumulation  in  the  blood  acts 
in  many  ways  so  prejudicially  on  the  system  at  large  (§  210). — That  the  quality 
of  the  exudation  is  in  some  degree  determined  by  the  seat  or  tissue  in  which  the 
Inflammation  occurs,  appears  from  the  different  character  of  the  product  of  the 
disordered  action  occurring  simultaneously  in  different  organs  of  the  same  in- 
dividual, and  apparently  under  the  operation  of  the  same  cause ;  thus  it  may 
happen  that  in  pleuro-pneumonia,  the  two  surfaces  of  the  pleura  become  con- 
nected by  an  organized  exudation  of  a  fibrous  character;  whilst  the  effusion  in 
the  substance  of  the  lung  is  rather  of  the  corpuscular  nature,  and  speedily  passes 
into  suppurative  degeneration.  Mr.  Paget  ingeniously  proposes  to  account  for 
the  determining  influence  in  question,  on  the  idea  that  the  inflammatory  pro- 
duct is  influenced  at  the  time  of  its  formation  by  the  assimilative  force  of  each 
part,  so  that  it  is  to  be  regarded  as  a  mixture  of  true  lymph  with  its  special 
product  of  assimilation;  thus  we  observe  that  in  inflammations  of  bone  the  lymph 
usually  ossifies,  in  those  of  ligaments  it  is  converted  into  a  tough  ligamentous 
tissue,  and  in  those  of  secreting  organs  it  contains  a  mixture  of  the  ordinary 
secreted  product. — The  mode  in  which  the  intensity  of  the  Inflammation  affects 
the  character  of  the  effused  lymph  is  twofold.  For,  in  the  first  place,  the 
nature  of  the  original  effusion  is  likely  to  vary  according  to  the  degree  in  which 
the  ordinary  nutritive  process  is  interrupted;  since,  the  more  intense  the  inflam- 
mation, the  less  will  be  the  assimilating  force  of  the  part,  and  the  more  will  the 
matters  effused  from  the  vessels  deviate  from  the  natural  plasma  which  would  be 
drawn  from  them  in  healthy  nutrition;  whilst,  on  the  other  hand,  when  the  in- 
flammation is  less  severe,  its  product  will  not  differ  so  widely  from  the  natural 
one,  and  will  from  the  first  tend  to  manifest  in  its  development  some  characters 
corresponding  to  those  of  the  natural  formations  of  the  part.  But,  secondly, 
the  influence  of  the  inflammation,  or  rather  of  the  depressed  vitality  of  the  in- 
flamed tissues,  is  shown  in  the  tendency  to  degeneration  which  it  impresses  on  the 
exuded  product;  so  that,  even  though  this  may  be  disposed  to  pass  on  under 
favorable  circumstances  to  the  complete  formation  of  an  organized  tissue,  its 
development  is  early  checked,  and  it  undergoes  retrograde  metamorphosis,  or 
else  from  the  very  commencement  its  development  takes  place  according  to  a 
lower  or  degraded  type,  The  normal  product  of  the  organization  of  either 
fibrinous  or  corpuscular  lymph  is  undoubtedly  a  tissue  closely  allied  to  the 
ordinary  areolar  or  connective;  it  is  of  this  that  false  membranes  and  adhesion 
are  formed,  and  that  the  material  of  most  thickenings  and  indurations  of  parts 
is  composed ;  and  it  is  by  the  production  of  this  tissue,  also,  that  losses  of  sub- 
stance are  in  the  first  instance  repaired,  and  that  divided  surfaces  are  made  to 
adhere.  The  mode  in  which  this  development  takes  place  has  been  already 
described  (§§  223,  224).  Various  kinds  of  degeneration  may  take  place,  ac- 
cording to  the  stage  at  which  the  developmental  process  is  checked;  and  among 
these,  in  tissues  which  have  once  attained  an  advanced  stage  of  development, 
the  most  common  is  the  fatty  (§  593). 

614.  But  the  most  frequent  of  all  the  degenerations  of  lymph,  being  almost 
invariable  when  the  lymph  is  placed  from  the  first  in  conditions  unfavorable  to 
its  development,  is  into  the  entirely  unorganizable  or  aplastic  product  which  is 
known  as  Pus.  This,  as  already  mentioned,  is  specially  liable  to  occur  in  lymph 
which  is  originally  rather  corpuscular  than  fibrinous  ;  and  every  gradation  may 
be  seen  from  the  most  characteristic  form  of  the  lymph-cell  to  that  of  the  pus-cell. 


572  OF   NUTRITION. 

But  it  would  seem  as  if  even  the  most  perfectly  fibrin ous  lymph  may  pass  almost 
immediately  into  the  condition  of  pus,  when  it  is  effused  among  tissues  which 
are  passing  rapidly  into  a  state  of  decomposition ;  and  thus  it  appears  to  be, 
that  in  a  phlegmonous  inflammation,  the  lymph  effused  into  the  parts  where  the 
inflammatory  process  has  been  most  intense  (the  stagnation  of  the  blood  being 
the  most  complete,  and  the  normal  tissues  most  disposed  to  disintegration),  does 
not  present  the  slightest  tendency  to  a  higher  type  of  organization,  but  is  de- 
veloped from  the  first  in  the  condition  of  pus,  which  fills  the  vacant  space  pre- 
viously occupied  by  living  tissue  ;  whilst,  in  the  surrounding  parts,  the  fibrinous 
effusion  produces  a  consolidation  of  the  tissue,  and  thus  forms  the  walls  of  the 
abscess,  by  which  the  purulent  effusion  is  limited.  Whether  the  disintegrating 
tissues  are  entirely  removed  by  absorption  (having  previously  undergone  that 
degenerative  softening  which  is  requisite  for  the  occurrence  of  this  process),  or 
whether  they  are  broken  up  and  dissolved  in  the  purulent  fluid,  is  a  point  not 
yet  determined. — The  conservative  nature  of  the  fibrinous  exudation,  and  the 
consequent  importance  of  fibrin  as  an  element  of  it,  are  well  shown  by  the 
results  of  its  deficiency.  Thus,  if  there  be  no  "  sac"  formed  around  a  collection 
of  pus,  this  fluid  infiltrates  through  the  tissues,  and  by  its  mere  presence  so  im- 
pairs their  nutrition,  that  a  corresponding  degradation  takes  place  in  the  cha- 
racters of  the  plastic  material  furnished  for  their  assimilation ;  and  thus  the 
purulent  effusion  spreads  without  limit,  and  the  tissues  through  which  it  perco- 
lates undergo  rapid  degeneration.  So,  again,  when  gangrene  is  spreading  by 
contiguity  (the  proximity  of  the  dead  tissue  tending  to  lower  the  vitality,  and 
even  to  occasion  the  death,  of  that  with  which  it  is  continuous),  it  is  only  when 
an  inflammatory  "  reaction"  takes  place,  or,  in  other  words,  when  an  exudation 
of  fibrinous  lymph  is  poured  into  the  substance  of  the  tissues  bordering  on  those 
which  have  lost  their  vitality,  that  a  line  of  demarcation  between  the  dead  and 
the  living  parts-is  formed.  And  generally,  it  may  be  said  that,  as  the  ultimate 
tendency  of  inflammation  is  to  produce  the  disintegration  of  the  part,  the 
ultimate  tendency  of  the  fibrinous  exudation  is  to  keep  its  elements  together, 
and  to  repair  the  losses  which  have  taken  place,  although  with  a  very  inferior 
material. — It  is  only,  however,  with  the  subsidence  of  the  inflammation,  and 
the  return  to  the  ordinary  type  of  nutrition,  that  the  highest  development  of  the 
lymph  can  take  place ;  and  it  is  in  proportion  as  this  occurs  more  speedily,  that 
the  recovery  of  the  organization  proper  to  the  part  is  more  completely  effected.1 
615.  In  persons  of  that  peculiar  constitution  which  is  termed  Scrofulous  or 
Strumous,  we  find  an  imperfectly  organizable  or  "  caco-plastic"  deposit,  or  even 
an  altogether  aplastic  product,  known  by  the  designation  of  tubercular  matter, 
frequently  taking  the  place  of  the  normal  elements  of  tissue ;  both  in  the  ordi- 
nary process  of  Nutrition,  and  still  more  when  Inflammation  is  set  up.  From 
an  examination  of  the  Blood  of  tuberculous  subjects  it  appears,  that  although 
the  bulk  of  the  coagulum  obtained  by  stirring  or  beating  it  is  usually  greater 
than  that  of  healthy  blood,  yet  this  coagulum  does  not  consist  of  well  elaborated 
fibrin ;  for  it  is  soft  and  loose,  and  contains  an  unusually  large  number  of 
Colorless  corpuscles,  whilst  the  Red  corpuscles  bear  an  unusually  small  propor- 
tion to  it.  We  can  understand,  therefore,  that  such  a  constant  deficiency  in 
plasticity  must  affect  the  ordinary  nutritive  process  -,  and  that  there  will  be  a 
liability  to  the  deposit  of  caco-plastic  products,  without  inflammation,  instead  of 
the  normal  elements  of  tissue.  Such  appears  to  be  the  history  of  the  formation 

1  The  Author  has  pleasure  in  referring  to  Mr.  Paget's  "  Lectures  on  Inflammation" 
(Medical  Gazette,  1850)  as  containing,  in  his  opinion,  the  best  exposition  of  the  subject 
yet  made  public ;  and  in  acknowledging  his  obligations  to  them  for  much  assistance  in  the 
short  view  of  it  given  above.  The  fundamental  doctrines  on  which  the  Author  would  now 
lay  the  greatest  stress,  however,  are  the  same  in  all  essential  particulars  with  those  which 
he  has  taught  in  previous  Editions  of  this  Treatise. 


ABNORMAL   FORMS   OF   NUTRITIVE   PROCESS. — INFLAMMATION.    573 

of  Tubercles  in  the  lungs  and  other  organs,  when  it  occurs  as  a  kind  of  meta- 
morphosis of  the  ordinary  Nutritive  process ;  and  in  this  manner  it  may  proceed 
insidiously  for  a  long  period,  so  that  a  large  part  of  the  tissue  of  the  lungs  shall 
be  replaced  by  tubercular  deposit,  without  any  other  ostensible  sign  than  an  in- 
creasing difficulty  of  respiration.  In  the  different  forms  of  tubercular  deposit, 
we  see  the  gradation  most  strikingly  displayed,  between  the  plastic  and  the 
aplastic  formations.  In  the  semi-transparent,  miliary,  gray,  and  tough  yellow 
forms  of  Tubercle,  we  find  traces  of  organization  in  the  form  of  cells  and  fibres, 
more  or  less  obvious ;  these  being  sometimes  almost  as  perfectly  formed  as  those 
of  plastic  lymph,  at  least  on  the  superficial  part  of  the  deposit,  which  is  in  im- 
mediate relation  with  the  living  structures  around ;  and  sometimes  so  degene- 
rated, as  scarcely  to  be  distinguishable.  In  no  instances  do  such  deposits  ever 
undergo  further  organization ;  and  therefore  they  must  be  regarded  as  caco-plastic. 
But  in  the  opaque,  crude,  or  yellow  Tubercle,  we  do  not  find  even  these  traces 
of  definite  structure ;  for  the  matter  of  which  it  consists  is  altogether  granular, 
more  resembling  that  which  we  find  in  an  albuminous  coagulum.  The  larger 
the  proportion  of  this  kind  of  matter  in  a  tubercular  deposit,  the  more  i§  it  prone 
to  soften,  whilst  the  semi-organized  tubercle  has  more  tendency  to  contraction. 
This  is  entirely  aplastic. — It  may  be  questioned,  however,  whether  Tubercular 
matter  is  not  always,  even  in  its  most  amorphous  state,  a  product  of  cell-forma- 
tion ;  and  whether  the  difference  between  the  amount  of  organization  which  its 
several  forms  present,  is  not  due  rather  to  a  variation  in  the  degree  of  its  sub- 
sequent degeneration  than  to  an  original  diversity  in  histological  condition.  On 
this  view,  Tubercle  is  to  be  considered  as  a  formation  sui  generis,  whose  pro- 
duction is  dependent  upon  a  special  taint  in  the  blood;  and  just  as -the  normal 
lymph-products  vary  greatly  in  their  degree  of  vitality,  so  that  some  undergo  a 
progressive  and  others  a  retrograde  metamorphosis,  so  may  tubercular  deposits 
either  retain  their  original  characters  more  or  less  completely  (though  never 
advancing  towards  a  higher  character),  or  may  undergo  a  very  early  and  complete 
degeneration.1  Now  although  Tubercular  matter  may  be  slowly  and  insidiously 
deposited,  by  a  kind  of  degradation  of  the  ordinary  Nutritive  process,  yet  it 
cannot  be  doubted  that  Inflammation  has  a  great  tendency  to  favor  it ;  so  that 
a  larger  quantity  may  be  produced  in  the  lungs,  after  a  Pneumonia  has  existed 
for  a  day  or  two,  than  it  would  have  required  years  to  generate  in  the  previous 
mode.  But  the  character  of  the  deposit  still  remains  the  same  ;  and  its  relation 
to  the  plastic  element  of  the  blood  is  shown  by  the  interesting  fact,  of  no  unfre- 
quent  occurrence — that,  in  a  Pneumonia  affecting  a  tuberculous  subject,  plastic 
lymph  is  often  thrown  out  in  one  part,  whilst  tubercular  matter  is  deposited  in 
another.  Now  Inflammation,  producing  a  rapid  deposition  of  tubercular  matter, 
is  peculiarly  liable  to  arise  in  organs,  which  have  been  previously  affected  with 
chronic  tubercular  deposits,  by  an  impairment  of  the  process  of  textural  Nutri- 
tion ;  for  these  deposits,  acting  like  foreign  bodies,  may  of  themselves  become 
sources  of  irritation ;  and  the  perversion  of  the  structure  and  functions  of  the 
part  renders  it  peculiarly  susceptible  of  the  influence  of  external  morbific  causes. 
616.  We  frequently  meet  with  abnormal  growths  of  a  Fatty,  Cartilaginous, 
Fibrous,  or  even  Bony  structure;  which  result  from  the  development  of  these 
tissues  in  unusual  situations,  and  appear  to  originate  in  some  perverted  action 
of  the  parts  themselves  (§  597). — But  there  is  another  remarkable  form  of  dis- 
ordered Nutrition,  which  is  concerned  in  producing  what  have  been  termed 
heterologous  growths ;  that  is,  masses  of  tissue  that  differ  in  character  from  any 
which  is  normally  present  in  the  body.  Most  of  these  are  included  under  the 
general  designation  of  Cancerous  or  Fungous  structures;  and  it  has  been  shown 

1  See  Mr.  Paget  in  the  "  Pathological  Catalogue  of  the  Hunterian  Museum,"  vol.  i.  p. 
134;  also  Dr.  Madden's  "  Thoughts  on  Pulmonary  Consumption." 


574  OF   SECRETION   AND   EXCRETION. 

by  Miiller  and  succeeding  inquirers,  that  the  new  growth  consists  of  a  mass  of 
cells;  which,  like  the  Vegetable  Fungi,  develop  themselves  with  great  rapidity; 
and  which  destroy  the  surrounding  tissues  by  their  pressure,  as  well  as  by  ab- 
stracting from  the  Blood  the  nourishment  which  was  destined  for  them.  These 
parasitic  masses  have  a  completely  independent  power  of  growth  and  reproduc- 
tion; and  they  can  be  propagated  by  inoculation,  which  may  convey  into  the 
tissues  of  the  animal  operated  on,  the  germs  of  the  peculiar  cells  that  constitute 
the  morbid  growth,  these  soon  developing  themselves  into  a  new  mass.  So  it 
may  be  by  the  diffusion  of  the  germs  produced  in  one  part,  through  the  whole 
fabric,  by  means  of  the  circulating  current,  that  the  tendency  to  re-appearance 
(which  is  one  great  feature  in  the  malignant  character  of  these  diseases)  is  oc- 
casioned. But  it  would  seem  more  probable  that  this  character  rather  depends 
upon  the  presence  of  a  morbid  matter  in  the  blood,  of  which  the  formation  of 
the  cancerous  tissue  is  only  the  manifestation  (§  120);  the  local  disease  thus 
being  the  consequence  of  a  constitutional  cachexia,  rather  than  the  constitu- 
tional affection  the  result  of  the  local  disease.1 


CHAPTER  XII. 

OF  SECRETION  AND  EXCRETION. 
| 

1. —  Of  Secretion  in  General. 

617.  THE  literal  meaning  of  the  term  Secretion  is  separation;  and  this  is 
nearly  its  true  acceptation  in  Physiology.  But  the  ordinary  processes  of  Nutri- 
tion involve  a  separation  of  certain  of  the  components  of  the  Blood,  which  are 
withdrawn  from  it  by  the  appropriating  power  of  the  solid  textures;  and  every 
such  removal  may  be  considered  in  the  light  of  an  act  of  excretion,  so  far  as  the 
blood  and  the  rest  of  the  organism  are  concerned  (§  202).  Moreover,  the  sepa- 
ration of  certain  matters  from  the  blood  in  a  fluid  state,  either  for  the  purpose  of 
being  cast  forth  from  the  body,  or  of  being  employed  for  some  special  -purpose 
within  it,  which  constitutes  what  is  ordinarily  known  as  Secretion,  is  effected  by 
an  agency  of  the  same  nature  with  that  whose  operation  constitutes  the  essential 
part  of  the  nutritive  process ;  namely,  the  production  and  growth  of  cells.  Hence 
there  is  no  other  fundamental  difference  between  the  two  processes,  than  such 
as  arises  out  of  the  diverse  destinations  of  the  separated  matters,  and  the  anatomi- 
cal arrangements  which  respect- 
Fig.  147.  ively  minister  to  these.  For 

the  products  of  the  secreting  ac- 
tion are  all  poured  forth  either 
upon  the  external  surface  of 
the  body,  or  upon  the  lining  of 
some  of  the  cavities  which  com- 
municatewith  it;  and  the  cells 
by  which  they  are  separated 

Plan  to  show  augmentation  of  surface  by  formation  of  pro-  from    ^      y^    uguall      ^^ 
cesses ;  a,  basement-membrane ;  p.  epithelial  layer  of  secreting  .  i      •  /•        •  A    i« 
cells;  c,  layer  of  capillary  vessels;  d,  simple  processes;  e,  f,  m    the    relation    of  epithelium- 
branched  or  subdivided  processes.  cells  to  those  prolongations  of 

1  See  Dr.  Walshe  on  "The  Nature  and  Treatment  of  Cancer ;"  and  Mr.  Simon's  "  Gene- 
ral Pathology,"  Lect.  vin.,  Am.  Ed. 


OF   SECRETION    IN    GENERAL. 


575 


the  skin  or  mucous  membranes 
that  form  either  the  projecting 
fringes  (Fig.  147),  or  the  folli- 
cles, or  extended  tubuli  (Fig. 
148),  of  which  the  Glandular  or- 
gans are  for  the  most  part  com- 
posed (§  235),  and  are  thus  readi- 
ly thrown  off  from  their  free  sur- 
faces. Thus,  the  act  of  Secre- 
tion essentially  consists  in  the 
successive  production  and  exu- 
viation of  the  cells  which  min- 
ister to  it;  these  cells  giving 
up,  by  rupture  or  deliquescence, 
the  substances  which  they  have 
eliminated  from  the  blood. 
Each  group  of  cells  is  adapted 
to  separate  a  product  of  some 
particular  kind,  which  consti- 
tutes its  special  pabulum  ;  and 
the  rate  of  its  production  seems 
to  depend  cdeteris  paribus  upon 
the  amount  of  that  pabulum 
supplied  by  the  circulating  fluid 
(§  120).  The  substances  at 
the  expense  of  which  the  se- 
creting cells  grow,  however, 
may  not  be  precisely  those 
which  are  subsequently  cast 
forth  at  their  death ;  for  it  is 
very  probable  that  some  of  them, 
at  least,  undergo  a  certain  de- 
gree of  chemical  transforma- 
tion by  the  agency  of  these 
cells;  the  characteristic  mate- 
rials of  the  several  secretions 
not  always  pre-existing  as  such 
in  the  blood. 

618.  A  distinction  may  be 
drawn,  as  regards  this-  point, 
between  those  Excretions,  the 
retention  of  whose  materials  in 
the  Blood  would  be  positively  injurious,  and  those  Secretions  which  are  des- 
tined for  particular  purposes  within  the  system,  and  the  cessation  of  which  has 
no  immediate  influence  on  any  other  function  than  those  for  which  they  are  re- 
spectively destined.  The  solid  matter  dissolved  in  the  fluids  of  the  latter  class 
is  little  else  than  a  portion  of  the  nutritive  constituents  of  the  blood ;  either  so 
little  altered  as  still  to  retain  its  nutritive  character,  as  is  the  case  with  the 
casein  of  Milk,  and  with  the  albuminous  constituent  of  the  Serous  fluid  of  areolar 
tissue  and  of  serous  and  synovial  membranes ;  or  in  a  state  of  incipient  retro- 
grade metamorphosis,  as  seems  to  be  the  case  with  the  peculiar  "  ferments"  of 
the  salivary,  gastric,  pancreatic,  and  intestinal  secretions.  On  the  other  hand, 
the  characteristic  ingredients  of  the  Excretions  are  very  different  in  character 
from  the  normal  elements  of  the  blood.  They  are  all  of  them  completely  unor- 
ganizable ;  and  they' possess,  for  the  most  part,  a  simple  atomic  constitution. 


Plan  of  extension  of  secreting  membrane,  by  inversion  or 
recession  in  form  of  cavities. — A,  simple  glands ;  a,  6,  c,  as  in  the 
last  figure;  g,  follicle;  h,  follicle  dilated  into  a  sacculus;  i,  follicle 
lengthened  into  a  tubule,  which  is  coiled  up. — B,  multilocular 
crypts;  fc,  of  tubular  form;  I,  saccular. — c,  Racemose  or  vesicular 
compound  glands ;  m,  entire  gland,  showing  branched  duct  and 
lobular  structure ;  n,  a  lobule  detached,  with  o,  branch  of  duct 
proceeding  from  it. — D,  Compound  Tubular  gland. 


576  OP    SECRETION    AND    EXCRETION. 

Some  of  them,  also,  have  a  tendency  to  assume  a  crystalline  form ;  which  is 
considered  by  Dr.  Prout  to  indicate  their  unfitness  to  enter  into  the  composition 
of  organized  tissues.  With  regard  to  some  of  the  chief  of  these,  there  is  suffi- 
cient evidence  of  their  existence,  in  small  quantity,  in  the  circulating  Blood ;  but 
it  is  also  clear,  that  they  exist  there  as  products  of  decomposition,  and  that  they 
are  destined  to  be  separated  from  it  as  speedily  as  possible.  If  their  separation 
be  prevented,  they  accumulate,  and  communicate  to  the  circulating  fluid  a  posi- 
tively deleterious  character.  Of  this  we  have  already  seen  a  striking  example 
in  the  case  of  Asphyxia  (§  574);  and  the  history  of  the  other  two  principal 
excretions,  the  'Bile  and  Urine,  will  furnish  evidence  to  the  same  effect. — As 
a  general  fact,  then,  it  may  be  stated  that  the  materials  of  the  Secretions  pre- 
exist in  the  Blood,  in  a  state  nearly  resembling  that  in  which  they  are  thrown 
off  by  the  secreting  organs ;  but  that  the  materials  of  those  secretions  which  are 
destined  to  perform  some  particular  function  within  the  economy,  are  derived 
from  the  substances  which  are  appropriated  to  its  general  purposes;  whilst  those 
of  the  excretions  are  the  result  of  the  destructive  changes  that  have  taken  place 
in  the  system,  and  cannot  be  retained  in  it  without  injury. 

619.  The  composition  and  uses  of  the  principal  Secretions  which  are  elabo- 
rated for  special  purposes  within  the  economy,  have  already  been  partly  described 
in  connection  with  the  functions  to  which  they  respectively  minister ;  and  the 
remainder  will  hereafter  come  under  notice  in  the  same  manner.  It  is  here  in- 
tended, however,  to  consider  that  important  system  of  Excretory  operations 
which  serves  to  maintain  the  purity  of  the  circulating  fluid  ;  by  removing  from 
it  those  products  of  the  disintegration  of  the  tissues  which  are  not  capable  of 
serving  any  purpose  in  the  nutrition  of  the  system,  and  which  even  act  upon  it 
as  poisons ;  and  also  by  withdrawing  the  products  (apparently  of  a  similar  cha- 
racter) of  the  decomposition  of  those  surplus  alimentary  materials  which,  not 
being  required  for  the  nutrition  of  the  tissues  undergo  retrograde  metamorphosis 
without  having  ever  undergone  the  process  of  organization.  The  process  of 
Respiration,  as  already  pointed  out  (§  535),  is  in  part  to  be  regarded  as  one  of 
an  excretory  character,  though  the  peculiar  manner  in  which  it  ministers  to  the 
removal  of  carbon  and  hydrogen  from  the  system,  and  its  subserviency  to  other 
purposes,  necessitate  its  separate  consideration.  The  true  Secreting  processes 
which  are  to  be  regarded  as  more  or  less  completely  excretory,  are  the  separation 
of  bile  by  the  Liver,  that  of  urine  by  the  Kidneys,  that  of  perspiration  by  the 
Skin,  and  that  of  fecal  matter  by  the  glandulae  of  the  Intestinal  surfuce.  The 
sum  total  of  these,  with  the  addition  of  the  carbonic  acid  and  watery  vapor 
poured  from  the  Lungs,  and  of  the  indigestible  matter  rejected  in  the  form  of 
feces,  must  be  equal  to  the  total  amount  of  the  solid  and  fluid  ingesta,  and  of 
the  oxygen  which  disappears  from  the  inspired  air;  the  weight  of  the  body 
remaining  the  same.  The  experiments  of  Dr.  Dalton  on  his  own  person  gave 
the  following  as  the  proportional  quantities  discharged  through  the  principal 
channels  of  excretion.1  The  mean  quantity  of  solid  and  liquid  Aliment  taken 
into  the  system  daily  (during  14  days  in  spring)  being  91  oz.,  or  about  5f  Ibs., 
the  average  amount  of  Feces  (including  part  of  the  solid  matter  of  the  bile)  was 
5  oz. ;  the  average  amount  of  Urine  was  48  £  oz.  daily  ;  and,  as  the  total  weight 
of  the  body  remained  the  same,  the  quantity  of  fluid  and  solid  matter  excreted 
by  the  Skin  and  the  Lungs  must  have  been  37 \  oz.  At  other  periods  of  the 
year,  a  variation  was  observed ;  especially  in  the  relative  amount  of  fluid  passing 
off  by  the  Urine,  and  by  Cutaneous  exhalation. — A  more  elaborate  series  of 
researches,  however,  has  been  recently  made  by  M.  Barral ;  a  part  of  whose 
results  has  been  given  in  the  preceding  chapter.  The  following  are  the  average 
daily  amounts  of  the  several  components  of  the  food  consumed,  and  of  the 

»  "  Edinburgh  New  Philosophical  Journal,"  1832,  1833. 


OF   SECRETION   IN   GENERAL. 


577 


various  excretions,  in  the  five  cases  already  referred  to  (§  566) ;  water  being 
excluded  in  each  case  : — 


Ingested  as  Food. 


Excreted. 


'In  Urine. 

In  Feces. 

By  Lungs  and  Skin. 

Carbon 

21770.4 

grs. 

1060.7 

grs. 

798.3 

grs. 

19911. 

4 

grs. 

Nitrogen 

1649.0 

« 

756.6 

tt 

142.0 

« 

750. 

4 

« 

Hydrogen 

3370.6 

« 

213.1 

u 

122.0 

tt 

3035. 

5 

« 

Oxygen 

16446.7 

« 

563.6 

(i 

467.8 

n 

15415 

.3 

i« 

Total 


43236.7 


2594.0 


1539.1 


39112.6    « 


The  water  ingested  amounted  on  an  average  to  about  three  times  the  solid 
matters ;  that  egested  in  various  ways  was  commonly  between  one-fifth  and  one- 
sixth  more,  showing  that  there  is  an  absolute  production  of  water  in  the  system 
(§  569).  The  following  table  gives  the  general  results  of  the  comparison  of  the 
matters  assimilated  and  excreted,  so  calculated  that  the  sum  in  each  case 
amounts  to  100  : — 


EXCRETED 

ASSIMILATED 

As  water  ;  by 

As  carbonic 

In  the 

In  other 

Food. 

Oxygen. 

exhalation. 

acid. 

evacuations. 

ways. 

A. 

72.2 

27.8 

33.8 

32.3 

33.2 

0.7 

B. 

75.4 

24.6 

36.1 

28.8 

34.7 

0.4 

C. 

76.7 

23.3 

38.2 

28.3 

33.2 

0.3 

D. 

75.3 

24.7 

14.5 

30.2 

54.6 

0.7 

E. 

72.5 

27.5 

31.0 

31.5 

36.9 

0.8 

620.  It  is .  obvious  that  the  demand  for  the  performance  of  the  Excretory 
processes  generally  will,  in  the  first  place,  arise,  as  in  the  case  of  Respiration, 
from  the  continual  disintegration  and  decay  to  which  the  organized  fabric  is 
liable  in  the  maintenance  of  a  merely  vegetative  existence ;  and  this  will  be  con- 
stant during  the  whole  life  of  Man,  as  of  any  other  warm-blooded  animal,  its 
amount  varying  with  the  degree  of  general  vital  activity. — But,  secondly,  the 
exercise  of  the  animal  functions,  involving  (as  this  does)  the  disintegration  of 
the  nervous  and  muscular  tissues  as  the  very  condition  of  the  evolution  of  their 
respective  forces,  becomes  a  special  source  of  the  production  of  excrementitious 
matter,  the  amount  of  which  will  vary  with  that  of  the  forces  thus  developed. — 
The  removal  of  excrementitious  matter  may  become  necessary,  thirdly,  from  the 
decomposition  of  superfluous  aliment,  which  has  never  been  assimilated.  This 
would  not  be  the  case,  if  the  amount  of  food  prepared  by  the  digestive  process, 
and  taken  up  by  absorption  into  the  current  of  the  circulation,  were  always 
strictly  proportional  to  the  demand  for  nutriment  created  by  the  wants  of  the 
system ;  but  such  a  limitation  seldom  exists  practically,  in  those  individuals  at 
least  who  do  not  feel  themselves  obliged  to  put  a  restraint  upon  the  indulgence 
of  their  ordinary  appetite ;  and  all  that  is  not  appropriated  to  the  reparation  of 
the  waste,  or  to  the  increase  of  the  bulk  of  the  body,  must  be  thrown  off  by  the 
excretory  organs.  It  has  been  already  shown  that  an  abundance  of  nutritive 
material  in  the  blood  does  not  augment  the  production  of  the  ordinary  tissues 
to  any  considerable  extent  (§  596)  ;  and  it  would  appear  that  all  such  materials 
as  are  not  speedily  assimilated  pass  rapidly  into  a  state  of  retrograde  meta- 
morphosis. How  large  a  proportion  of  the  solid  matters  of  the  urine  ordina- 
rily has  this  source,  will  appear  from  facts  hereafter  to  be  stated  (§  640).  More- 
over, in  the  last  place,  it  cannot  be  deemed  improbable  that  the  changes  which 
the  crude  aliment  undergoes,  from  the  time  of  its  first  reception  into  the  absorb- 
ents and  bloodvessels,  to  that  of  its  conversion  into  organized  tissues  and  special 
37 


578  OP   SECRETION   AND   EXCRETION. 

secretions,  involve  the  liberation  of  many  products  of  which  the  elements  are 
superfluous,  and  therefore  injurious  to  the  system  if  retained  in  it.  Thus  it  has 
been  shown  to  be  quite  possible,  that,  in  the  production  of  Gluten  (gelatin)  from 
Albumen,  an  equivalent  of  Choleic  (tauro-cholic)  acid  may  be  generated  (§  91, 
VI.).  The  condition  of  Organic  Chemistry,  however,  is  not  yet  such  as  to  allow 
of  anything  being  advanced  with  certainty  under  this  head. — From  these  various 
sources,  then,  a  large  amount  of  effete  matter  is  being  continually  received  back 
from  the  tissues  into  the  current  of  the  circulation,  or  is  generated  in  the  blood 
by  the  changes  to  which  it  is  itself  subject;  and  it  is  the  great  object  of  the 
Excretory  apparatus  to  free  that  fluid  from  the  products  which  would  rapidly 
accumulate  in  it,  but  for  the  provision  which  is  thus  made  for  their  removal. 

621.  Notwithstanding  that,  under  ordinary  circumstances,  the  several  parts 
of  the  Excretory  apparatus  are  limited,  each  to  its  own  special  function,  yet  we 
see  that  there  are  certain  complementary  relations  between  them,  which  make 
the  action  of  one  to  a  certain  extent  vicarious  with  that  of  another.     Such  a 
relation  exists,  for  instance,  between  the  lungs  on  one  side,  and  the  liver  and 
intestinal  glandulse  on  the  other ;  for,  the  more  active  the  respiration,  the  less 
bile  is  secreted  ;  whilst,  if  the  respiration  be  lowered  in  amount  by  inactivity  of 
body  and  a  high  external  temperature,  a  larger  proportion  of  unoxidized  or  im- 
perfectly oxidized  excrementitious  matters  accumulate  in  the  blood,  giving  rise 
to  that  augmented  production  both  of  the  biliary  and  of  the  fecal  excretions 
which  constitutes  diarrhoea.1     And  thus,  on  the  other  hand,  when  the  liver  is 
not  adequately  effecting  the  depuration  of  the  blood  from  the  constituents  of  bile, 
an  augmentation  of  the  respiration  by  active  exercise  in  a  low  temperature  gives 
most  effectual  relief. — Still  more  obviously  vicarious,  however,  are  the  kidneys 
and  the  skin ;  for  here  we  find  that  not  only  do  the  kidneys  allow  the  transu- 
dation  of  whatever  superfluous  water  may  remain  in  the  circulating  current, 
after  a  sufficient  amount  has  been  exhaled  from  the  skin  to  keep  .down  the  tem- 
perature of  the  body  to  its  normal  standard,  but  the  skin  actually  assists  in  the 
elimination  of  one  of  those  products  of  the  metamorphosis  of  the  azotized  tissues, 
the  removal  of  which  has  been  until  recently  considered  as  the  special  function 
of  the  kidney.     Consequently,  whenever  the  due  action  of  the  skin  as  an  ex- 
creting organ  is  interfered  with,  it  is  the  •  kidney  especially  that  will  be  called 
on  to  take  its  place ;  whilst,  on  the  other  hand,  if  it  be  thought  necessary  to 
relieve  the  kidney,  this  may  be  most  effectually  done  by  stimulating  the  skin  to 
increased  excretory  activity. 

622.  This  vicariousness  of  function  among  the  Excretory  organs  presents 
itself  far  more  remarkably,  however,  in  certain  states  of  disease ;  in  which  a 
complete  "metastasis  of  secretion"  exhibits  itself.     The  capability  of  one  organ 
thus  to  take  upon  itself  the  special  actions  of  another,  seems  to  have  reference 
to  the  community  of  function  which  exists  in  the  secreting  surface  among  the 
lower  animals,  in  which  there  is  none  of  that  "  specialization"  or  setting  apart 
for  particular  offices,  which  we  see  in  the  higher ;  for  it  seems  to  be  a  general 
law  in  Physiology,  that,  even  where  the  different  functions  are  most  highly 
specialized,  the  general  structure  retains,  more  or  less,  the  primitive  community 
of  action  which  characterized  it  in  the  lowest  grade  of  development.3     It  is  in 
regard  to  the  Urinary  excretion,  that  the  evidence  on  this  point  is  most  com- 
plete ;  for  it  seems  to  be  established  by  a  great  mass  of  observations,  that  urine, 
or  a  fluid  presenting  its  essential  characters,  may  pass  off  by  the  mucous  mem- 
brane of  the  intestinal  canal,  by  the  salivary,  lachrymal,  and  mammary  glands, 

1  Such  is  probably  the  occasion  of  the  "bilious  attacks"  and  "autumnal  cholera"  so 
prevalent  at  the  close  of  the  summer ;  the  subjects  of  these  being  most  commonly  persons 
who  have  not  reduced  their  consumption  of  food  during  the  warm  season,  in  accordance 
with  the  diminished  demand  for  the  production  of  heat  within  the  body. 

2  See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  \\  351,  605,  Am.  Ed. 


OF   SECRETION   IN   GENERAL. 


579 


by  the  testes,  by  the  ears,  nose,  and  navel,  by  parts  of  the  ordinary  cutaneous 
surface,  and  even  by  serous  membranes,  such  as  the  arachnoid  lining  the  ven- 
tricles of  the  brain,  the  pleura,  and  the  peritoneum.  A  considerable  number  of 
such  cases  was  collected  by  Haller  i1  many  more  were  brought  together  by 
Nysten  ;a  more  recently  Burdach  has  furnished  a  full  summary  of  the  most  im- 
portant phenomena  of  the  kind  ;3  and  Dr.  Laycock  has  compiled  a  valuable  col- 
lection of  cases  of  urinary  metastasis  occurring  as  complications  of  hysteria.4 
The  following  table  of  cases  referred  to  by  the  last  of  these  authors  will  give 
some  idea  of  the  relative  frequency  of  the  different  forms  of  this  curious  affec- 
tion : — 


Vomit. 

Stool. 

Ears. 

Eyes. 

Saliva. 

Nose. 

Mammae. 

Navel. 

Skin. 

Total. 

33 

20 

4 

4 

5 

3 

4 

34 

17 

124 

It  is  to  be  borne  in  mind,  however,  that  cases  of  hysterical  ischuria  are  fre- 
quently complicated  with  that  strange  moral  perversion  which  leads  to  the 
most  persevering  and  ingenious  attempts  at  deceit;  and  there  can  be  little  doubt 
that  a  good  many  of  the  instances  on  record,  especially  of  urinous  vomiting, 
are  by  no  means  veritable  examples  of  metastasis.  The  proofs  of  the  fact  we 
are  seeking  to  establish  are,  therefore,  much  more  satisfactory  when  drawn  from 
experiments  upon  animals,  or  from  pathological  observations,  about  which,  from 
their  very  nature,  there  can  be  no  mistake.  Thus  Mayer5  found  that  when  the 
two  kidneys  were  extirpated  in  the  guinea-pig,  the  cavities  of  the  peritoneum 
and  the  pleura,  the  ventricles  of  the  brain,  the  stomach,  and  the  intestinal 
canal,  contained  a  brownish  liquid  having  the  odor  of  urine ;  that  the  tears 
exhaled  the  same  odor ;  that  the  gall-bladder  contained  a  brownish  liquid  not 
resembling  bile ;  and  that  the  testicles,  the  epididymis,  the  vasa  deferentia,  and 
the  vesiculae  seminales,  were  gorged  with  a  liquid  perfectly  similar  to  urine. 
Chirac  and  Helvetius  are  quoted  by  Haller  as  having  tied  the  renal  arteries  in 
dogs,  and  having  then  remarked  that  a  urinous  fluid  was  passed  off  from  the 
stomach  by  vomiting.  A  remarkable  case  is  quoted  by  Nysten  from  Zeviani, 
in  which  a  young  woman  having  received  an  incised  wound  on  the  external 
genitals,  which  would  not  heal,  the  urine  gradually  became  more  scanty,  and  at 
last  none  could  be  passed  ev,en  with  the  assistance  of  the  catheter ;  at  last 
dropsy  supervened,  with  sweats  of  a  urinous  odor,  and  vomiting  of  a  urinous 
fluid,  which  continued  daily  for  thirty-three  years.  On  post-mortem  examina- 
tion, the  kidneys  were  found  disorganized,  the  right  ureter  entirely  obliterated 
and  the  left  nearly  so,  and  the  bladder  contracted  to  the  size  of  a  pigeon's  egg. 
In  some  other  instances,  the  urine  appears  to  have  been  secreted,  and  then 
reabsorbed  in  consequence  of  some  obstruction  to  its  exit  through  the  urinary 
passages.  Thus  Nysten  quotes  from  Wrisberg  a  case  in  which,  the  urethra 
having  been  partially  obstructed  for  ten  years  by  an  enlarged  prostate,  the 
bladder  was  so  distended  as  to  contain  ten  pounds  of  urine ;  and  the  serosity  of 
the  pericardium  and  of  the  ventricles  of  the  brain  exhaled  a  urinous  odor.  He 
cites  other  instances  in  which  the  presence  of  calculi  in  the  bladder  prevented 
the  due  discharge  of  the  secretion ;  and  in  which  a  urinous  liquid  was  ejected 
from  the  stomach  by  vomiting,  or  was  discharged  by  stool.  A  still  more  re- 
markable case  is  recorded  of  a  girl  born  without  either  anus  or  external  geni- 

Elementa  Physiologise,"  torn.  ii.  p.  370. 

Recherches  de  Physiologic  et  de  Chimie  pathologique,"  p.  265. 

Trait6  de  Physiologic"  (Jourdan's  Translation),  vol.  viii.  p.  248,  et  sea. 

Edinb.  Med.  and  Surg.  Journ.,"  1838. 

Zeitschrift  fur  Physiologic,"  torn.  ii.  p.  270. 


580  OF    SECRETION   AND    EXCRETION. 

tals,  who  nevertheless  remained  in  good  health  to  the  age  of  fifteen  years,  pass- 
ing her  urine  from  the  nipples,  and  getting  rid  of  fecal  matters  by  vomiting. 
There  are  cases,  moreover,  in  which  it  would  seem  that  the  mucous  lining  of  the 
urinary  bladder  must  have  had  a  special  power  of  secreting  urine ;  the  usual 
discharge  having  taken  place  to  the  end  of  life,  when,  as  appeared  by  post- 
mortem examination,  the  kidneys  were   so  completely  disorganized  that  they 
could  not  have  furnished  it,  or  had  been  prevented  by  original  malformation, 
or  by  ligature  of  the  urethra,  from  discharging  it  into  the  bladder.     A  con- 
siderable number  of  these  have  been  collected  by  Burdach.1     In  all  the  older 
statements  of  this  kind,  there  is  a  deficiency  of  evidence  that  the  fluids  were 
really  urinous,  urea  not  having  been  obtained  from  them  by  chemical  analysis, 
and  the  smell  having  been  chiefly  relied  upon.     The  urinous  odor,  however, 
when  distinct,  is  probably  nearly  as  good  an  indication  of  the  presence  of  the 
most  characteristic  constituent  of  human  urine  as  is  the  sight  of  the  urea  in  its 
separated  form.     The  passage  of  a  urinous  fluid  from  the  skin  has  been  fre- 
quently observed  in  cases  in  which  the  renal  secretion  was  scanty ;  and  the 
critical  sweats,  by  which  attacks  of  gout  sometimes  terminate,  contain  urates 
and  phosphates  in  such  abundance  as  to  form  a  powdery  deposit  on  the  surface. 
— The  metastasis  of  the  Biliary  secretion  is  familiar  to  every  practitioner,  as 
being  the  change  on  which  jaundice  is  dependent.     It  is  not,  however,  in  every 
case  of  yellowish-brown  discoloration  of  the  tissues  that  we  are  to  impute  such 
discoloration  to  the  presence  of  biliary  matter  j  and  we  can  only  safely  do  so, 
when  we  have   at  the  same  time  evidence  of  concurrent  disturbance  of  the 
biliary  apparatus.     The  urinary  apparatus  then  becomes  the  principal  channel 
through  which  the  biliary  matter  is  eliminated ;  the  urine  becomes  tinged  with 
the  coloring  principle  of  bile,  being  sometimes  of  a  yellowish  or  orange  hue, 
and  sometimes  of  a  brown  color  with  a  considerable  sediment ;  and  the  presence 
of  the  most  characteristic  constituents  of  the  bile  has  been  determined  in  the 
urine.     The  same  result  presents  itself,  when  the  biliary  duct  has  been  arti- 
ficially obstructed  by  ligature.     Other  secretions  have  been  found  tinged  with 
the  coloring  matter  of  bile  :  thus  the  pancreatic  fluid  has  been  seen  of  a  yellow 
color  in  jaundice ;  and  the  milk  has  presented  not  merely  the  hue,  but  the 
characteristic  bitterness,  of  the  biliary  secretion.     The  cutaneous  transpiration 
is  not  unfrequently  so  much  impregnated  with  biliary  matter,  as  to  communi- 
cate the  tinge  to  the  linen  covering  the  skin ;  and  even  the  sputa  of  patients 
affected  with  bilious  fevers  have  been  observed  to  be  similarly  colored,  and  have 
be*n  found  to  contain  biliary  matter.     The  secretions  of  serous  membranes,  also, 
have  been  frequently  seen  to  present  the  characteristic  hue  of  bile;  and  biliary 
matter  has  been  detected,  by  analysis,  in  the  fluid  of  the  pleural  and  peritoneal 
cavities.      Biliary  matter,  however,  when  unduly  present  in  the  circulating 
current,  is  not  removed  from  it  by  the  secreting  organs  alone ;  for  it  seems  to 
be  withdrawn  also  in  the  ordinary  operations  of  nutrition,  entering  into  combi- 
nation with  the  solid  tissues.     Thus,  in  persons  affected  with  jaundice,  we  find 
the  skin,  the  mucous  and  serous  membranes,  the  lymphatic  glands,  the  brain, 
the  fibrous  tissues,  the  cartilages,  the  bones  and  teeth,  and  even  the  hair,  pene- 
trated with  the  coloring  matter  of  the  bile,  which  they  must  have  withdrawn 
from  the  blood,  and  which  seems  to  have  a  particular  affinity  for  the  gelatinous 
tissues.     It  is  impossible  at  present  to  say,  however,  to  what  extent  the  more 
characteristic  ingredients  of  the  bile  are  thus  withdrawn  from  the  blood ;  for 
the  presence  of  its  coloring  matter  cannot  by  any  means  be  taken  as  an  indica- 
tion that  its  peculiar  resinoid  acids  are  also  incorporated  with  the  normal  com- 
ponents of  the  tissues. 

1  "Zeitschrift  fur  Physiologic,"  torn.  ii.  pp.  253,  254. 


THE  LIVER.  —  SECRETION  OF  BILE. 


581 


2. —  The  Liver. — Secretion  of  Bile. 

623.  The  Liver  is  probably  more  constantly  present,  under  some  form  or 
other,  throughout  the  entire  animal  series,  than  any  other  gland.  Its  form  and 
condition  vary  so  greatly,  however,  in  different  tribes,  that,  without  a  knowledge 
of  its  essential  structure,  we  should  be  disposed  to  question  whether  any  identity 
of  character  exists  among  the  several  organs  which  are  regarded  as  Hepatic.  It 
is,  in  fact,  the  presence  of  bile-secreting  cells,  that  must  be  held  to  constitute  a 
Liver ;  and  these  may  be  scattered  over  the  general  lining  membrane  of  the  ali- 
mentary canal,  or  may  be  restricted  within  follicles  which  are  formed  by  depres- 
sions of  it ',  these  follicles,  again,  may  be  multiplied  in  some  particular  spot,  so  as 
to  be  aggregated  into  a  mass,  or  may  be  extended  into  long  tubes.  In  all  the  In- 
vertebrata,  however,  the  Liver  is  obviously  conformable  to  the  general  type  of 
glandular  structures ;  the  hepatic  cells  being  in  immediate  relation  with  a  base- 
ment-membrane, and  being  discharged  upon  a  free  surface.  This  will  be  readily 

Fig.  149. 


Lobule  of  Liver  of  Squilla  Mantis:  A,  exterior ;  B,  the  same  cut  open. 

understood  from  an  examination  of  any  one  of  the  higher  forms  of  it,  such  as  that 
presented  in  the  liver  of  the  Crab  (Fig.  149),  which,  like  the  liver  of  the  Mollusca 
generally,  is  a  lobulated  glandular  mass,  formed  by  the  aggregation  of  a  multi- 
tude of  follicles  with  distinct  caecal  terminations ;  these  follicles  discharging  their 
secreted  products  into  cavities  which  occupy  the  centre  of  the  lobules,  whence 
they  are  collected  by  the  ducts  which  discharge  them  into  the  alimentary  canal. 
On  a  careful  examination  of  these  follicles  (Fig.  150),  and  a  comparison  of 
the  size  and  contents  of  the  cells  at  the  bottom  and  towards  the  outlet,  it  becomes 
evident  that  the  cells  originate  in  the  former  situation,  and  gradually  increase 
in  size  as  they  advance  towards  the  latter.  It  is  also  to  be  observed  that  the 
cells  which  lie  deepest  in  the  caecum  (a,  6)  contain  for  the  most  part  the  yellow 
granular  matter,  which  may  be  regarded  as  the  proper  biliary  secretion ;  but 
as  they  increase  in  size,  there  is  also  an  increase  in  the  quantity  of  oil-globules 
which  they  contain  (c),  until  past  the  middle  of  the  follicle,  where  they  are 
found  full  of  oil,  so  as  to  have  the  appearance  of  ordinary  fat-cells  (d,  e).  From 
this  it  happens,  that  when  an  entire  caecum  is  examined  microscopically,  its  lower 
half  appears  filled  with  a  finely  granular  matter,  intermingled  with  nucleated 
particles ;  and  the  upper  half  with  a  mass  of  fat-cells,  whose  nuclei  are  ob- 
scured by  the  oily  particles.1 — In  Vertebrated  animals,  however,  the  Liver  seems 


1  See  Dr.  l^eidy's  "  Researches  into  the  Comparative  Structure  of  the  Liver,"  in 
Journ.  of  Med.  ScL,"  Jan.  1848. 


Amer. 


582 


OF  SECRETION  AND  EXCRETION. 


Fig.  150. 


One  of  the  hepatic  caeca  of  Astacus 
affinis  (Cray  fish),  highly  magnified, 
showing  the  progress  of  development 
of  the  secreting  cells  from  the  blind 
extremity  to  the  mouth  of  the  folli- 
cles; specimens  of  these,  in  then-  suc- 
cessive stages,  are  shown  separately 
at  a,  b,  c,  d,  $. 


to  be  constructed  upon  a  different  plan ;  and  the 
relation  between  the  secreting  cells  of  which  its 
mass  is  composed,  and  the  ducts  by  which  their 
product  is  conveyed  away,  is  very  difficult  to  de- 
termine satisfactorily  except  in  certain  Fishes,  in 
whose  liver  the  ducts  may  be  shown  to  terminate 
in  caeca  filled  with  cells,  as  in  the  lower  animals.1 
In  ascending  through  the  Yertebrated  series,  this 
organ  presents  a  more  and  more  solid  parenchy- 
matous  texture,  which  strikingly  contrasts  with  its 
loosely  lobulated  racemose  aspect  in  even  the  highest 
Invertebrata.  This  character  is  very  obvious  in 
the  liver  of  Man,  which  is  peculiarly  firm  and  com- 
pact, and  has  less  of  connective  tissue  between  its 
different  parts  than  is  found  in  that  of  many  other 
Mammalia.  It  is  observable,  moreover,  in  the 
Human  liver,  that  certain  parts  are  rudimentary 
which  are  elsewhere  fully  developed.  Thus  in  the 
Carnivora  and  Rodentia,  which  present  the  most 
complex  form  of  liver  that  we  meet  with  among 
Mammalia,  there  are  five,  distinct  parts ;  namely, 
a  "  central"  or  principal  lobe,  and  a  right  and  left 
"  lateral"  lobe,  each  with  its  "  lobular  appendage." 
The  whole  mass  of  the  liver  of  Man  (Fig.  151), 
which  we  are  accustomed  to  describe  as  consisting 
of  a  "right"  and  "left"  lobe,  does  in  reality 
form  but  one  (there  being  no  real  division  be- 
tween its  two  portions),  which  must  be  regarded  as 
the  "central"  lobe;  the  "lobulus  Spigelii"  is  the 
rudiment  of  aright  "  lateral"  lobe,  and  the  "lobulus 

Fig.  151. 


The  inferior  or  concave  surface  of  the  Liver,  showing  its  subdivisions  into  lobes :  1,  centre  of  the  right  lobe; 
2,  centre  of  the  left  lobe ;  3,  its  anterior,  inferior,  or  thin  margin ;  4,  its  posterior,  thick,  or  diaphragmatic 
portion;  5,  the  right  extremity ;  6,  the  left  extremity ;  7,  the  notch  in  the  anterior  margin  ;  8,  the  umbilical 
or  longitudinal  fissure;  9,  the  round  ligament  or  remains  of  the  umbilical  vein;  10,  the  portion  of  the  sus- 
pensory ligament  in  connection  with  the  round  ligament;  11,  pons  hepatis,  or  band  of  liver  across  the  umbili- 
cal fissure ;  12,  posterior  end  of  longitudinal  fissure ;  13,  14,  attachment  of  the  obliterated  ductus  venosus  to 
the  ascending  vena  cava;  15,  transverse  fissure ;  16,  section  of  the  hepatic  duct ;  17,  hepatic  artery;  18,  its 
branches;  19,  vena  portarum;  20,  its  sinus,  or  division  into  right  and  left  branches;  21,  fibrous  remains  of  the 
ductus  venosus ;  22,  gall-bladder;  21,  its  neck ;  24,  lobulus  quartus ;  25,  lobulus  Spigelii ;  26,  lobulus  cauda- 
tus;  27,  inferior  vena  cava;  28,  curvature  of  liver  to  fit  the  ascending  colon;  29,  depression  to  fit  the  right 
kidney;  30,  upper  portion  of  its  right  concave  surface  over  the  renal  capsule;  31,  portion  of  liver  uncovered 
by  the  peritoneum ;  32,  inferior  edge  of  the  coronary  ligament  in  the  liver ;  33,  depression  made  by  the  verte- 
bral column. 

1  See  Dr.  T.  Williams,  in  "Guy's  Hospital  Reports,"  1846,  p.  323. 


THE  LIVER.  —  SECRETION   OF   BILE.  583 

caudatus"  is  its  "  lobular  appendage ;"  but  the  left  "  lateral"  lobe,  with  its 
"  lobular  appendage,"  is  altogether  undeveloped. 

624.  In  examining  into  the  minute  structure  of  the  Liver,  we  shall  first  con- 
,ider  the  peculiarities  in  the  arrangement  of  its  Bloodvessels  and  Ducts ;  for  our 
present  knowledge  of  which  we  are  almost  entirely  indebted  to  Mr.  Kiernan,1 
whose  account  of  them  will  be  here  followed ;  his  researches  having  been  con- 
firmed in  all  essential  particulars  by  other  Anatomists. — When  the  Liver  is 
closely  examined  with  the  naked  eye,  it  is  seen  to  be  made  up  of  a  great  number 
of  small  granular  bodies,  about  the  size  of  a  millet-seed,  of  an  irregular  form, 
and  presenting  a  number  of  rounded  projecting  processes  upon  their  surfaces. 
These  are  commonly  termed  lobules,  although  by  some  Anatomists  they  are 
spoken  of  as  acini.  When  divided  longitudinally,  they  have  a  somewhat  foli- 
ated appearance  (Fig.  152),  arising  from  the  distribution  of  the  Hepatic  Vein ; 
which,  passing  into  the  centre  of  each  divi- 
sion, is  termed  the  intralobul&r  vein.  The 
exterior  of  each  lobule  is  covered  by  a  pro- 
cess of  the  "capsule  of  Glisson;"  which  is 
very  dense  in  the  Pig  and  other  animals, 
but  is  so  thin  as  to  be  almost  undistin- 
guishable  in  the  Human  liver.  Its  substance 
is  composed  of  the  minute  ramifications  of 
the  before-mentioned  vessels,  arranged  in  the 
manner  preset- tly  to  be  described;  the  spaces 
between  whu  ,  are  filled  with  a  parenchyma, 

Composed     Of     nucleated      Cells,     like     those  Connection  of  the  Lobules  of  the  Liver  with 

Shown    in    Fig.    157,  B.         The    Structure    of  «"  Hepatic  Vein:  1,  trunk  of  the  vein;  2,2, 

,    ,    ,     ,       9              .'                                       .IT  lobules  depending  from  its  branches,  like  leaies 

each  lobule,  then,  gives  US  the  essential  cha-  On  a  tree;  the  centre  of  each  being  occupied  by 

racters    Of  the    whole    gland. The    lobules,  a  venous  twig,  the  Intralobular  Vein. 

when  transversely  divided,  are  usually  found 

to  present  somewhat  of  a  pentagonal  or  a  hexagonal  shape,  the  angles  being 
somewhat  rounded,  so  as  to  form  a  series  of  passages  or  wfcrlobular  spaces 
(Fig.  159);  in  these  lie  the  branches  of  the  Vena  Portge,  and  of  the  Hepatic 
Artery  and  Duct,  from  which  are  derived  the  plexuses  that  compose  the  lobules. 
Each  lobule,  when  examined  with  the  microscope,  is  found  to  be  apparently 
composed  of  numerous  minute  bodies  of  yellowish  color,  and  of  various  forms, 
connected  together  by  vessels;  to  these  the  name  of  acini  was  given  by  Mal- 
pighi ;  and  to  these,  if  they  deserve  a  name,  it  ought  to  be  restricted.  They 
will  be  presently  shown,  however,  to  be  nothing  else  than  the  irregular  islets, 
left  between  the  meshes  of  the  plexus  formed  by  the  ultimate  ramifications  of 
the  portal  vein.  The  Vena  Portae,  which  is  formed  by  the  convergence  of  the 
veins  that  return  the  blood  from  the  chylopoietic  viscera,  probably  also  receives 
the  blood  which  is  conveyed  to  the  liver  for  the  purpose  of  nutrition  by  the 
Hepatic  Artery.  Like  an  artery,  it  gradually  subdivides  into  smaller  and  yet 
smaller  branches;  and  at  last  it  forms  a  plexus  of  vessels,  which  lie  in  the  inter- 
lobular  spaces,  and  spread  with  the  freest  inosculation  throughout  the  entire 
Liver.  To  these  vessels,  the  name  of  mfcrlobular  Veins  was  given  by  Mr. 
Kiernan.  They  ramify  in  the  capsules  of  the  lobules,  covering  with  their 
ramifications  the  whole  external  surface  of  these;  and  then  enter  their  substance. 
When  they  enter  the  lobules,  they  are  termed  lobular  veins;  and  the  plexus 
formed  by  their  convergence  from  the  circumference  of  each  lobule  towards  its 
centre  (where  their  ultimate  ramifications  terminate  in  those  of  the  intralobular 
or  hepatic  vein),  is  designated  as  the  lobular  venous  plexus  (Fig.  153).  In  the 
islets  of  this  plexus  (the  acini  of  Malpighi),  the  ramifications  of  the  hepatic 

1  "Philosophical  Transactions,"  1833. 


584 


OF   SECRETION   AND   EXCRETION. 


Horizontal  section  of  three  superficial  Lobules, 
showing  the  two  principal  systems  of  Bloodvessels  : 
1, 1,  mfralobular  veins,  proceeding  from  the  Hepatic 
veins ;  2,  2,  interlobular  plexus,  formed  by  branches 
of  the  Portal  vein. 


duct  are  distributed,  in  the  manner  to  be  presently  described. — The  Hepatic 
Artery  sends  branches  to  every  part  of  the  Liver,  supplying  the  walls  of  the 
portal  and  hepatic  veins,  and  of  the  hepatic  ducts,  as  well  as  Glisson's  capsule. 
The  principal  distribution  of  its  branches,  however,  is  to  the  Lobules,  which 
they  reach,  in  the  same  manner  with  the  portal  vessels  and  biliary  ducts,  by 

spreading  themselves  through  the  inter- 
Fig.  153.  lobular  spaces.  There  they  ramify 
upon  the  interlobular  ducts,  and  upon 
the  capsular  surface  of  the  lobules,  which 
they  then  penetrate;  their  minuteness 
prevents  their  distribution  within  the 
lobules  from  being  clearly  demonstra- 
ble ;  but,  as  they  enter  along  with  the 
biliary  ducts,  there  can  be  little  doubt 
that,  here  as  elsewhere,  they  are  prin- 
cipally distributed  upon  the  walls  of 
these.  As  to  the  ultimate  termination 
of  the  capillaries  of  the  hepatic  artery 
— whether  they  enter  the  Portal  plexus, 
or  the  Hepatic  Vein — there  is  a  differ- 
ence of  opinion  amongst  anatomists;  the 
former  view  being  upheld  by  Kiernan, 
the  latter  by  Miiller.  The  question  is 
a  very  interesting  one  in  a  physiological 
point  of  view;  since,  if  the  former  ac- 
count be  the  true  one,  the  blood  which 
is  brought  to  the  liver  by  the  hepatic 
artery  becomes  subservient  to  the  secre- 
tion of  bile,  only  by  passing  into  the  portal  plexus;  whilst,  if  the  latter  be  the 
correct  statement,  either  the  arterial  blood  is  not  at  all  subservient  to  the  for- 
mation of  bile,  or  the  secretion  can  be  elaborated  from  the  arterial  capillaries. 
The  experiments  of  Mr.  Kiernan  have  satisfactorily  proved  that  the  intralobu- 
lar  or  hepatic  veins  cannot  be  filled  by  injection  from  the  hepatic  artery,  though 
they  may  be  readily  filled  from  the  portal  plexus;  whilst,  on  the  other  hand, 
there  is  reason  to  believe  that  a  very  fine  injection  into  the  hepatic  arteries 
will  find  its  way  into  the  portal  plexus.1  It  is  certain  that  all  the  branches  of 
the  hepatic  artery,  of  which  the  termination  can  be  ascertained,  end  in  the  vena 
portse;  a  free  capillary  communication  existing  between  their  two  systems  of 
branches,  on  the  walls  of  the  larger  bloodvessels  and  ducts.  According  to 
Miiller,  there  is  an  ultimate  plexus  of  capillary  vessels,  with  which  all  the  three 
systems  freely  communicate;  but  for  this  idea  there  is  no  adequate  foundation; 
and  it  is  inconsistent  with  the  fact  just  stated,  that  injection  into  the  hepatic 
artery  does  not  return  by  the  hepatic  vein.  The  views  of  Mr.  Kiernan  upon  this 
point  have  received  important  confirmation  from  the  researches  of  Mr.  Bowman 
on  the  circulation  in  the  Kidney  (§  635). — It  now  only  remains  to  describe  the 
Hepatic  Veins,  the  branches  of  which  occupy  the  interior  of  the  lobules,  and 
are  termed  m^ralobular  veins  (1, 1,  Figs.  153,  154).  On  making  a  transverse 
section  of  a  lobule,  it  is  seen  that  the  central  vessel  is  formed  by  the  converg- 
ence of  from  four  to  six  or  eight  minute  venules,  which  arise  from  the 
processes  upon  the  surface  of  the  lobule.  In  the  superficial  lobules  (by  which 
term  are  designated  those  lobules  which  lie  upon  the  exterior  of  the  glandular 
substance,  not  only  upon  the  surface  of  the  liver,  but  also  against  the  walls  of  the 

1  This  is  stated  to  have  been  the  case  in  the  injections  of  Lieberkiihn,  although  Mr. 
Kiernan  has  not  succeeded  in  effecting  it. 


SHE   LIVER.  —  SECRETION   OP   BILE.  585 

larger  vessels,  ducts,  &c.)  the  intralobular  veins  commence  directly  from  their 
surface ;  and  the  minute  venules  of  which  each  is  composed  may  be  seen  in  an 
ordinary  injection,  converging  from  the  circumference  towards  the  centre,  as  in 
the  transverse  section  of  other  lobules.  The  intralobular  veins  terminate  in 
the  larger  trunks,  which  pass  along  the  bases  of  the  lobules,  collecting  from  them 
their  venous  blood ;  these  are  called  by  Mr.  Kiernan  sullobular  veins.  The 
main  trunk  of  the  Hepatic  Vein  terminates  in  the  ascending  Vena  Cava. 

625.  The  Hepatic  Duct  forms,  by 
its  subdivision  and  ramification,  an 
interlobular  plexus  very  like  that 
of  the  portal  vein;  but  the  anasto- 
mosis between  the  branches  going 
to  the  different  lobules  is  less  inti- 
mate than  that  of  the  interlobular 
veins,  and  cannot  be  directly  de- 
monstrated }  although  Mr.  Kiernan 
thinks  that  his  experiments  leave 
but  little  doubt  of  its  existence — 
a  communication  (which  cannot  be 
seen  to  be  established  by  any  nearer 

channel)  being    proved    to  exist  be-          Horizontal  section  of  two  superficial  Lobules,  showing 

tween    the    right    and    left   primary       J^e  interlobular &*™  of  Biliary  Dwts:  1,1,  intralobu- 

i   i ...  /»   ,  i       j  rni        •  lar  vems  5  2>  2>  trunks  of  biliary  ducts,  proceeding  from 

subdivisions  of  the  duct.     The  in-    the  plexus  which  traverges  the  lobuleg;  3j  interlobular 

terlobular    ducts    ramify    upon     the       tissue  ;  4,  parenchyma  of  the  lobules. 

capsular  surface  of  the  lobules,  with 

the  branches  of  the  portal  vein  and  hepatic  artery ;  they  then  enter  its  substance, 
and  subdivide  into  minute  branches,  which  are  believed  to  anastomose  with  each 
other,  and  to  form  a  reticulated  plexus,  termed  by  Mr.  K.  the  lobular  biliary 
plexus  (Fig.  154).  This  plexus  constitutes  the  principal  part  of  the  substance 
of  the  lobule;  and  when  seen  through  the  meshes  of  the  portal  plexus,  gives  rise 
to  the  appearance  of  caecal  terminations  of  ducts.  No  such  terminations  of  these 
ducts  have  been  traced,  however,  in  the  adult  liver  of  any  of  the  higher  animals, 
although  they  are  sufficiently  evident  in  the  embryonic  condition.  From  the 
analogy  of  other  organs,  there  would  seem  good  reason  to  believe  that  the  ulti- 
mate ramifications  of  the  hepatic  ducts  anastomose  freely  together,  and  that  they 
form  a  network,  in  which  their  terminations  are  lost,  as  it  were,  without  forming 
true  caeca.  This  view  of  the  matter  finds  confirmation  in  the  curious  fact  pointed 
out  by  Mr.  Kiernan,  that,  in  the  left  lateral  ligament,  the  essential  parts  of  a 
lobule  are  found  in  the  simplest  form  and  arrangement.  From  the  edge  of  the 
liver  next  to  the  ligament,  numerous  ducts  emerge,  which  ramify  between  the 
two  layers  of  peritoneum  of  which  the  ligament  is  composed.  They  are  ac- 
companied by  branches  of  the  portal  and  hepatic  veins,  and  of  the  hepatic  artery  ; 
which  also  ramify  in  this  ligament,  especially  around  the  parietes  of  the  ducts. 
These  ducts,  of  which  some  are  occasionally  of  considerable  size,  divide,  subdivide 
and  anastomose  with  each  other ;  and  the  meshes  formed  by  the  network  of 
larger  or  excreting  ducts  are  occupied  by  minute  plexuses  of  their  ultimate 
ramifications  or  secreting  ducts. — The  more  recent  observations  of  Dr.  Leidy 
(loc.  cit.)  harmonize  precisely  with  the  view  promulgated  by  Mr.  Kiernan,  and 
seem  to  confirm  the  idea,  that  here,  as  elsewhere,  the  hepatic  cells  are  inclosed 
in  a  limitary  membrane.  "  Th'e  lobules  are  composed  of  an  intertexture  of 
biliary  tubes  (Fig.  155) ;  and  in  the  interspaces  of  the  network  the  bloodvessels 
ramify  and  form  among  themselves  an  intricate  anastomosis,  the  whole  being 
intimately  connected  together  by  a  combination  of  the  white  fibrous  and  the 
yellow  elastic  tissue.  In  structure,  the  biliary  tubes  (Figs.  155,  156)  corre- 
spond with  those  of  Invertebrata,  consisting  of  cylinders  of  basement-membrane, 


586 


OF   SECRETION   AND   EXCRETION. 


containing  numerous  secreting  cells,  and  the  only  difference  exists  in  the  ar- 
rangement, the  free  tubes  of  the  lower  animals  becoming  anastomosed  on  forming 


Fig.  155. 


Fig.  156. 


Fig.  155.  Transverse  section  of  a  Lobule  of  the  Human  Liver,  showing  the  reticular  arrangement  of 
the  Bile-ducts,  with  some  of  the  hranches  of  the  Hepatic  Vein  in  the  centre,  and  those  of  the  Portal 
System  at  the  periphery. 

Fig.  156.  A  small  portion  of  this  section  more  highly  magnified,  showing  the  secreting  cells  within 
the  tubes. 

an  intertexture  ia  the  Vertebrata.     The  tubuli  vary  in  size  in  an  unimportant 
degree  in  different  animals,  and  also  in  the  same  animal,  being  generally  from 

two  to  two  and  a  half 

Fig.  157.  times  the  diameter  of 

the  secreting  cells. 
The  tubes  of  one  lob- 
ule are  distinct  from 
those  of  the  neighbor- 
ing *lobuli,  or  only 
communicate  indirect- 
ly by  means  of  the 
trunks  of  hepatic 
ducts,  originating  from 
the  tubes,  and  lying 
in  the  interspaces  of 
the  lobuli.  The  se- 
creting cells  (Fig.  157, 
B)  are  irregularly  an- 
gular or  polygonal  in 
form,  from  mutual 
pressure,  and  line  the 
interior  surface  of  the 
tubes.  They  vary  in 
size  in  a  moderate  de- 
gree in  different  animals,  and  also  in  the  same  animal,  appearing  to  depend  upon 
certain  conditions  of  the  animal  and  liver."1  '  The  subsequent  observations  of 
Dr.  Natalis  Gruillot3  are  mainly  to  the  same  effect.  He  has  not  been  able,  how- 

1  See  "American  Journal  of  the  Medical  Sciences,"  Jan.  1848. — Dr.  Leidy  does  not 
specify  the  mode  in  which  his  preparations  have  been  made ;  but  we  understand  that  his 
plan  is  to  dry  a  small  portion  of  injected  liver,  then  to  make  as  thin  a  slice  of  this  as  pos- 
sible, and  to  examine  this  slice  when  restored  to  its  original  condition  by  moisture. 

2  "Annales  des  Sciences  Naturelles,"  Mars,  1848. 


A,  portion  of  a  Biliary  Tithe,  from  Human  Liver,  with  the  secreting  cells : 
B,  secreting  cells  detached,  a,  in  their  normal  state,  fc,  a  cell  more  highly 
magnified,  showing  the  nucleus  and  distinct  oil-particles,  c,  in  various  stages 
of  fatty  degeneration. 


THE  LIVER.  —  SECRETION   OP   BILE.  587 

ever,  to  distinguish  membranous  parietes  around  these  canals ;  and  he  considers 
that  they  are  simply  channelled-out  in  the  parenchyma  of  the  liver,  the  particles 
of  which  form  its  sole  borders.  Professor  Retzius,  however,  by  a  particular 
method  of  preparation,  has  been  able  to  demonstrate  the  existence  of  a  basement- 
membrane  surrounding  the  biliary  cells,  and  forming  a  plexus  of  hepatic  ducts, 
as  described  by  Dr.  Leidy.1 

626.  The  biliary  cells  of  the  Human  Liver  (Fig.  157,  B)  are  usually  of  a 
flattened  spheroidal  form,  and  from  l-1500th  to  1 -2000th  of  an  inch  in  diameter. 
Each  of  them  presents  a  distinct  nucleus;  and  the  cavity  of  the  cell  is  occupied 
by  yellow  amorphous  biliary  matter,  usually  having  one  or  two  large  adipose  glob- 
ules, or  five  or  six  small  ones,  intermingled  with  it  (a,  6).     The  size  and  number 
of  these,  however,  vary  considerably,  according  to  the  nature  of  the  food,  the 
amount  of  exercise  recently  taken,  and  other  circumstances.     If  an  animal  be 
very  fat  or  well  fed,  especially  with  farinaceous  or  oleaginous  substances,  the 
proportion  of  adipose  particles  is  much  greater  than  in  an  animal  moderately 
fed  and  taking  much  exercise  (c).     The  size  of  the  globules  varies  from  that  of 
mere  points,  scarcely  distinguishable  from  the  granular  contents  of  the  cells 
except  by  their  intense  blackness,  up  to  one-fourth  of  the  diameter  of  the  cell. 
The  finely-granular  matter  is  the  portion  from  which  the  color  of  the  cell  is 
derived;  it  seems  to  fill  the  space  not  occupied  by  the  oil-globules;  and  it  often 
obscures  the  nucleus,  so  that  the  latter  cannot  be  distinguished  until  acetic  acid 
is  added,  which  makes  the  granular  matter  more  transparent  without  affecting 
the  nucleus. — A  still  greater  accumulation  of  adipose  particles  in  the  biliary 
cells  gives  rise,  as  was  first  pointed  out  by  Mr.  Bowman,3  to  the  peculiar  con- 
dition termed  "  fatty  liver"  (§  628).3 

627.  The  knowledge  of  the  distribution  of  the  Biliary  ducts,  and  of  the  two 
chief  systems  of  Bloodvessels,  in  the  lobules  of  the  Liver,  has  enabled  Mr. 
Kiernan  to  give  a  most  satisfactory  explanation  of  appearances,  by  which  Patho- 
logical anatomists  had  been  previously  much  perplexed.     When  the  liver  is  in 
a  state  of  Anaemia  (which  rarely  happens  as  a  natural  condition,  although  it 
may  be  induced  by  bleeding  an  animal  to  death),  the  whole  substance  of  the 
lobules  is  pale,  as  represented  in  Fig.  158.     In  general,  however,  the  liver  is 
more  or  less  congested  at  the  moment  of  death ;  and  this  congestion  may  mani- 
fest itself  in  several  ways.     The  whole  substance  may  be  congested ;  in  which 
case  the  lobules  present  a  nearly  uniform  dark  color  throughout  their  substance, 
their  centres  being  usually  more  deeply-colored  than  the  margins.     An  appear- 
ance more  frequently  offered  after  death,  however,  is  that  represented  at  Fig. 
159,  and  termed  by  Mr.  Kiernan  the  first  stage  of  Hepatic  Venous  congestion. 
In  this,  the  isolated  centres  of  the  lobules  alone  present  the  color  of  sanguine- 

1  See  the  account  of  his  researches  in  "  Muller's  Archiv.,"  1850.     His  method  consists 
in  first  macerating  a  piece  of  liver  in  ether,  then  drying  it,  cutting  thin  sections  from  it 
in  this  condition,  and  soaking  these  in  water  until  they  become  transparent. — For  a  very 
different  view  of  the  structure  of  the  Liver,  see  Dr.  Handfield  Jones's  papers  in  the 
"Philosophical  Transactions"  for  1846  and  1849. 

2  "Medical  Gazette,"  Jan.  1842. 

3  It  has  been  recently  maintained  by  Dr.  Handfield  Jones  ("Medical  Times,"  Jan.  31, 
1852,  p.  122),  that  "the  cells  of  the  liver  are  not  the  constant  and  necessary  agents  in  the 
secretion  of  bile,  and  that  the  occurrence  of  this  secretion  in  them  is  rather  to  be  viewed 
as  an  accidental  if  not  a  pathological  phenomenon ;  the  real  function  of  the  cell  being  to 
produce  the  sugar  out  of  the  blood  supplied  to  them,  which  is  absorbed  and  carried  off  by 
the  hepatic  vein."     The  arguments  adduced  in  support  of  this  opinion  are,  that  in  per- 
fectly healthy  livers  of  animals,  bile  is  not  ordinarily  to  be  seen  in  the  contents  of  the 
cells,  while  it  is  very  common  in  those  of  persons  who  have  died  of  various  diseases ;  and 
that  in  extracts  made  of  the  parenchymata  of  various  livers,  Pettenkofer's  test  gave  very 
little  or  no  evidence  of  the  presence  of  biliary  matter. — A  far  larger  amount  of  research 
is  necessary,  however,  to  establish  such  a  novel  and  (at  first  sight)  very  improbable  view. 


588 


OP   SECRETION   AND   EXCRETION. 


ous  congestion ;  and  the  surrounding  substance  varies  from  a  yellowish-white, 
yellow,  or  greenish  color,  according  to  the  quantity  and  quality  of  the  bile  which 


Fig.  158. 


Fig.  159. 


1,  angular  lobules  in  a  state  of  Ancemia,  as  they 
appear  on  the  external  surface  of  the  liver ;  2,  in- 
terlobular  spaces ;  3,  interlobular  fissures ;  4.  inter- 
lobular  veins,  occupying  the  centres  of  the  lobules ; 
5,  smaller  veins,  terminating  in  the  central  veins. 


A,  rounded  lobules  in  first  stage  of  Hepatic  Venous 
congestion,  as  they  appear  on  the  surface  of  the  liver : 
B,  interlobular  spaces  and  fissures. 


it  contains.  This  accumulation  of  the  blood  in  the  hepatic  veins,  and  the 
emptiness  of  the  portal  plexus,  seem  due  to  the  continuance  of  capillary  action 
after  the  general  circulation  has  ceased,  a  circumstance  to  which  we  find  an  ex- 
act parallel  in  the  emptiness  of  the  systemic  arteries,  and  the  fulness  of  the 
veins,  after  most  kinds  of  death. — In  the  second  stage  of  Hepatic  Venous  con- 
gestion, the  accumulation  of  blood  is  found  not  only  in  the  intralobular  veins, 
but  even  in  parts  of  the  portal  or  lobular  venous  plexus.  The  parts  which  are 
freest  from  it  are  those  surrounding  the  interlobular  spaces  \  so  that  the  non- 
congested  substance  here  appears  in  the  form  of  circular  or  irregular  patches, 
in  the  midst  of  which  the  spaces  and  fissures  are  seen  (Fig.  160). *  Although 
the  portal  as  well  as  the  hepatic  venous  system  is  thus  involved  in  this  form  of 
congestion,  yet,  as  the  obstruction  evidently  originates  in  the  latter,  the  term 
given  by  Mr.  Kiernan  is  still  applicable ;  and  it  is  important  to  distinguish  this 
appearance  from  that  next  to  be  described.  The  second  stage  of  Hepatic  Venous 
congestion  very  commonly  attends  disease  of  the  heart,  and  other  disorders  in 
which  there  is  an  impediment  to  the  venous  circulation ;  and  in  combination 
with  accumulation  in  the  biliary  ducts,  it  gives  rise  to  those  various  appearances, 
which  are  known  under  the  name  of  dram-drinkers'  or  nutmeg  liver. — The  other 
form  of  partial  congestion  arises  from  an  accumulation  of  blood  in  the  portal 
veins,  with  a  reverse  condition  of  the  hepatic  or  intralobular  veins ;  in  this  con- 
dition, which  Mr.  K.  designates  as  Portal  Venous  congestion,  the  marginal  por- 
tions of  the  lobules  are  of  deeper  color  than  usual,  and  form  a  continuous 
network,  the  isolated  spaces  between  which  are  occupied  by  the  non-congested 
portions  (Fig.  161).  This  is  a  very  rare  occurrence;  having  been  seen  by  Mr. 
K.  in  children  only. — These  differences  fully  explain  the  diversity  of  the  state- 
ments of  different  anatomists,  as  to  the  relative  position  of  the  so-called  red 
and  yelfaw  substances ;  for  it  now  appears  that  the  red  substance  is  the  congested 
portion  of  the  lobules,  which  may  be  either  interior  or  exterior,  or  irregularly 

1  This  very  common  aspect  of  the  Liver,  which  presents  numerous  modifications,  has 
been  a  source  of  great  perplexity  to  those  who  have  studied  the  minute  anatomy  of  this 
organ,  and  has  even  led  Anatomists  of  the  highest  eminence  into  serious  errors.  See  Mr. 
Erasmus  Wilson,  in  "Cyclop,  of  Anat.  and  PhysioL,"  vol.  iii.  pp.  185,  186. 


THE   LIVER.  —  SECRETION    OP  BILE. 


589 


disposed ;  whilst  the  yellow  is  the  non-congested  part,  in  which  the  biliary  plexus 
shows  itself  more-  or  less  distinctly. — Another  very  interesting  form  of  Patho- 


Fig.  160. 


Fig.  161. 


A,  lobules  in  the  second  stage  of  Hepatic  Venom  con- 
gestion :  B  and  c,  interlobular  spaces ;  D,  congested 
intralobular  veins ;  E,  congested  patches,  extending 
to  the  circumference  of  the  lobules ;  F,  non-congested 
portions  of  lobules. 


A,  lobules  as  they  appear  on  the  surface  in  a  state 
of  Portal  Venous  congestion:  s,  interlobular  spaces 
and  fissures;  c,  intralobular  hepatic  yeins,  containing 
no  blood ;  D,  the  central  portions  in  a  state  of  anaemia  ; 
z,  the  marginal  portions  in  a  congested  state. 


logical  change  in  the  aspect  of  the  Liver,  which  the  knowledge  of  the  structure 
of  the  lobules  enables  us  to  comprehend,  is  that  to  which  the  name  of  Cirrhosis 
has  been  given.  This  has  been  erroneously  attributed  to  the  presence  of  a  new 
deposit,  analogous  to  that  of  tubercular  matter ;  but  it  is  really  due  to  atrophy 
and  partial  congestion  in  the  liver  itself.  It  is  described  by  Laennec  as  usually 
presenting  itself  in  small  masses,  varying  in  size  from  a  cherry-stone  to  a  millet- 
seed,  and  scattered  through  the  substance  of  the  liver.  When  these  are  minute 
and  closely  set,  they  impart  what  appears  at  first  to  be  a  uniform  brownish- 
yellow  tint  to  the  divided  surface  of  the  liver ;  but  when  the  tissue  is  more  at- 
tentively examined,  their  separation  becomes  evident.  These  small  masses  are  not 
distinct  lobules  in  a  variable  state  of  hypertrophy  (as  supposed  by  Cruveilhier), 
but  small  uncongested  patches,  composed  of  parts  of  several  adjoining  lobules; 
and  having  one  or  more  interlobular  spaces  for  a  centre;  and  the  biliary  plex- 
uses of  these,  being  filled  with  bile,  give  them  their  yellow  color.  On  the  other 
hand,  there  is  an  atrophy,  more  or  less  complete,  of  the  portions  of  the  sub- 
stance of  the  liver  intervening  between  them ;  so  that  the  bulk  of  the  whole 
organ  is  much  diminished  very  commonly  to  one-half  and  sometimes  to  one-third 
of  its  original  size. 

628.  Among  the  most  frequent  of  the  pathological  changes  which  the  assist- 
ance of  the  Microscope  enables  us  to  discern  in  the  biliary  cells,  is  that  engorge- 
ment with  adipose  particles,  which  is  observable  in  . 
the  condition  of  the  organ  known  as  "  fatty  liver" 
(Fig.  162).     This  state  having  been  frequently  ob- 
served in  individuals  who   have  died   of  phthisis 
or  other  diseases  of  the  lungs  involving  deficient 
respiration,  has  been  imputed  to  a  vicarious  action 
of  the  liver,  which  (as  was  supposed)  made  an  effort 
thus  to  discharge  the  hydrocarbonaceous  matters 
that  should  normally  be  eliminated  by  the  lungs. 
But  such  a  view  is  inconsistent  with  various  facts,     globules. 


Fig.  162. 


590  OF    SECRETION   AND   EXCRETION. 

which  show  (as  Mr.  Paget  has  justly  remarked1)  that  the  fatty  liver  is  an  inactive 
organ,  one  which  is  discharging  less  than  its  ordinary  function,  and  that  the  accu- 
mulation of  fat  in  its  cells  is  rather  to  be  considered  as  a  mark  of  "  fatty  degene- 
ration. "  For  the  nuclei  disappear,  the  proper  coloring  matter  of  the  bile  can 
no  longer  be  distinguished,  the  liver  increases  in  size  owing  to  the  tardy  or 
obstructed  removal  of  its  cells,  and  its  paleness  indicates  a  slow  and  defective 
supply  of  blood;  moreover,  the  fatty  liver  presents  itself  in  many  cases  in  which 
there  has  been  no  deficiency  of  respiration,  and  is  frequently  absent  in  phthisical 
subjects;  and  there  is  no  evidence  whatever  that  the  organ  when  in  this  state 
discharges  any  unusual  amount  of  fat  into  the  alimentary  canal.  Still  there 
can  be  little  doubt  that  the  accumulation  of  adipose  matter  in  the  biliary  cells 
is  favored  by  deficiency  of  respiration,  since  this  will  tend  to  increase  the  quan- 
tity which  the  circulating  fluid  contains.  Throughout  the  Animal  series,  more- 
over, a  marked  relation  of  reciprocity  is  discernible  between  the  amount  of  fat 
contained  in  the  Hepatic  apparatus,  and  the  activity  of  the  respiratory  function ; 
thus  in  Birds,  the  biliary  cells  scarcely  contain  any  fatty  particles,  whilst  in 
Reptiles  and  Fishes  they  are  loaded  with  them ;  and  nearly  the  same  difference 
may  be  seen  between  the  biliary  cells  of  Insects  and  those  of  Crustacea  and 
Mollusca. — Various  other  alterations,  however,  have  been  noticed.  Dr.  T. 
Williams  mentions3  that,  in  a  case  of  obstruction  of  the  ductus  choledochus  by 
malignant  disease,  which  occasioned  complete  interruption  to  the  passage  of  bile, 
and  consequent  jaundice,  scarcely  an  entire  nucleated  cell  could  be  discovered 
by  attentive  examination  of  a  large  part  of  the  organ.  Nothing  more  than 
minute  free  particles  of  fat,  and  free  floating  amorphous  glandular  matter,  could 
be  detected.  He  further  states  that,  in  a  case  of  fever,  the  hepatic  cells  were 
found  to  be  almost  entirely  destitute  of  fatty  particles;  and  that  in  what  is  known 
as  "granular  liver,"  the  granules  (which  have  much  the  appearance  of  tubercles) 
consist  of  cells,  which  strongly  resemble  the  ordinary  cells  of  the  parenchyma 
of  the  liver  in  every  respect,  except  that  they  are  almost  or  completely  destitute  of 
yellow  contents.  Similar  observations  have  been  also  recorded  by  Dr.  G.  Budd.3 
— In  two  cases  of  jaundice  examined  by  Mr.  Gulliver,  the  hepatic  cells  were 
gorged  with  biliary  matter ;  some  of  them  to  such  an  extent  that  they  had 
become  nearly  opaque.  Perhaps,  if  this  condition  had  continued,  these  cells 
would  have  been  all  ruptured,  and  the  state  of  the  organ  would  have  resembled 
that  described  by  Dr.  Williams. 

629.  Previously  to  birth,  the  Liver  is  the  only  decarbonizing  organ  in  the 
system,  the  lungs  being  at  that  time  inert ;  and  nearly  the  whole  of  the  blood 
returning  from  the  placenta  passes  through  this  organ  before  proceeding  to  the 
heart,  to  be  distributed  by  it  to  the  body  generally.  The  liver  of  the  foetus, 
moreover,  is  considerably  larger  in  proportion  than  that  of  the  adult;  and  its 
functional  importance  is  obviously  great.  There  can  be  no  question  that  the 
secretion  of  bile  is  actively  taking  place  during  the  latter  part  (at  least)  of  foetal 
life ;  for  a  large  accumulation  of  it  presents  itself  in  the  intestinal  canal  of  the 
new-born  infant — the  meconium  having  been  found  by  the  analyses  of  Simon4 
and  of  Frerichs5  to  be  chiefly  made  up  of  the  characteristic  components  of  the 
biliary  secretion. — As  soon,  however,  as  the  placental  circulation  is  cut  off,  and 
the  Lungs  of  the  infant  come  into  play,  the  supply  of  blood  transmitted  to  the 
liver  is  almost  immediately  lessened ;  this  diminution  being  usually  made  very 
evident  within  a  short  time  after  birth,  by  the  comparative  paleness  of  the  sub- 
stance of  the  gland.  It  has  been  proposed  to  give  this  fact  a  practical  bearing, 

"Lectures  on  Nutrition,"  &c.,  in  "Medical  Gazette,"  1847,  vol.  xl.  p.  235. 

"  Guy's  Hospital  Reports,"  1843. 

See  his  Treatise  on  "Diseases  of  the  Liver,"  2d  edit.,  pp.  211,  247,  &c. 

"Animal  Chemistry,"  translated  by  Dr.  Day,  p.  672,  Am.  Ed. 

Dr.  Day's  "  Report  on  Chemistry,"  in  "  Ranking' s  Half-yearly  Abstract,"  vol.  iii.  p.  314. 


THE   LIVER.  —  SECRETION    OF   BILE.  591 

in  those  judicial  inquiries  which  are  directed  to  the  determination  of  the  ques- 
tion, whether  or  not  an  Infant  has  respired  after  birth;  it  having  been  con- 
ceived, that  the  diversion  of  the  current  of  blood  from  the  Liver  to  the  Lungs, 
consequent  upon  the  first  inspiration,  would  be  sufficient  to  make  a  certain  dif- 
ference in  their  relative  weights,  if  that  inspiration  had  taken  place.  More 
careful  and  extended  observations,  however,  have  satisfactorily  proved  that, 
although  an  increase  in  the  weight  of  the  Lungs,  and  a  diminution  of  that  of 
the  Liver,  are  generally  found  to  exist  after  respiration  has  been  fully  established, 
they  are  not  by  any  means  constantly  produced  when  the  inspirations  have  been 
feeble,  as  they  frequently  are  for  some  hours  or  days  after  birth;  whilst,  on  the 
other  hand,  it  is  not  uncommon  to  meet,  in  infants  that  have  not  breathed,  with 
Lungs  as  heavy,  and  Livers  as  light,  as  in  the  average  of  those  which  have 
respired.1 

630.  We  have  now  to  consider  the  conditions  under  which  the  secretion  of 
Bile  takes  place;  and  one  of  the  most  important  of  these  is  the  character  of  the 
Blood  with  which  the  organ  is  supplied.  We  have  seen  that  there  is  anatomical 
reason  for  the  belief  that  the  blood  supplied  by  the  hepatic  artery  is  not  directly 
concerned  in  the  secretion ;  but  that  it  first  serves  for  the  nutrition  of  the  organ, 
and  then,  passing  into  the  portal  system  (in  the  same  manner  as  does  the  blood 
of  the  mesenteric  and  other  arteries),  forms  part  of  the  mass  of  venous  blood, 
from  which  the  secreting  cells  elaborate  their  product.  This  view  is  borne  out 
by  the  results  of  experiment  and  of  pathological  observation.  For,  if  the  Vena 
Portse  be  tied,  the  secretion  of  bile  still  continues,  though  in  diminished  quan- 
tity; and  several  cases  are  on  record,  in  which,  through  a  malformation,  the 
vena  portae  terminated  in  the  vena  cava  without  ramifying  through  the  liver, 
and  in  which  secretion  of  bile  took  place — evidently  from  the  blood  of  the 
hepatic  artery,  which  had  become  venous  by  circulating  through  the  substance 
of  the  liver;  and  this  blood  appears2  to  have  passed  into  the  ramifications  of 
the  umbilical  vein,  which  formed  a  plexus  in  the  lobules,  exactly  resembling 
the  ordinary  portal  plexus.  It  must  be  remembered,  however,  that  in  all  these 
instances,  the  arterial  Blood  will  become  abnormally  charged  with  the  elements 
of  bile ;  since  the  blood  of  the  chylopoietic  viscera,  from  which  it  ought  to  have 
been  separated,  returns  to  the  heart  without  undergoing  any  such  purification; 
and  the  secretion  of  bile  from  the  blood  supplied  by  the  hepatic  artery,  under 
such  circumstances,  cannot,  therefore,  be  considered  as  proving  that  the  arterial 
blood  is  ordinarily  concerned  in  the  secretion  to  the  same  degree. — The  fact 
that  this  secretion  is  normally  formed  from  venous  blood  is  a  strong  indication 
that  one  purpose  of  its  separation  is  the  removal  of  a  portion  of  the  products  of 
the  disintegration  of  the  tissues  :  and  that  a  large  amount  of  hydrocarbonaceous 
matter  will  remain  to  be  excreted,  after  the  constituents  of  urea  have  been  sub- 
tracted from  those  of  albumen  or  gelatin,  has  been  already  pointed  out  (§  91,  vi.). 
But,  again,  the  position  of  the  Liver  in  regard  to  the  mesenteric  vessels  is  such, 
that  all  the  new  alimentary  materials  which  are  received  by  them  must  pass 
through  it  and  be  submitted  to  its  action,  before  they  enter  the  general  current 
of  the  circulation;  and  there  are  several  circumstances  which  render  it  probable 
that  it  exercises  a  depurative  as  well  as  an  assimilating  power  over  these,  and 
that  whilst  it  assists  in  preparing  for  nutrition  those  azotized  substances  which 
are  capable  of  being  applied  to  that  purpose,  and  also  transforms  non-azotized 
matters  into  compounds  which  are  more  ready  to  undergo  combustion  and  are 
thus  better  fitted  for  sustaining  the  heat  of  the  body  by  respiration,  it  also  elimi- 
nates certain  substances  whose  passage  into  the  general  circulation  would  be 

1  See  Dr.  Guy,  in  "Edinb.  Med.  and  Surg.  Journ.,"  vols.  Ivi.  and  Ivii. 

2  This,  at  least,  was  found  to  be  the  case  in  the  only  instance  in  which  the  Liver  was 
examined  with  sufficient  care.     See  Kiernan,  loc.  cit. 


592  OF   SECRETION   AND   EXCRETION. 

injurious. — This  is  assuredly  the  case  with  regard  to  copper  and  certain  other 
mineral  poisons  (§  89) ;  and  it  seems  also  to  be  true  with  respect  to  pus,  which, 
when  taken  up  from  ulcers  in  the  intestinal  walls,  is  stopped  in  the  liver,  and 
not  unfrequently  gives  rise  to  abscesses  in  its  substance.1 

631.  When  from  any  cause  the  secretion  of  Bile  is  suspended,  the  substances 
at  the  expense  of  which  it  is  formed  accumulate  in  the  Blood ;  and  their  excre- 
mentitious  character  is  strikingly  demonstrated  by  the  disturbance  of  other 
functions,  especially  those  of  the  Nervous  system,  which  then  ensues.  When 
the  suppression  is  complete,  the  patient  suddenly  becomes  jaundiced,  the  powers 
of  that  system  are  speedily  lowered  (almost  as  by  a  narcotic  poison),  and  death 
rapidly  supervenes.3  When  the  secretion  is  diminished,  but  not  suspended,  the 
same  symptoms  present  themselves  in  a  less  aggravated  form.  It  is  probable 
that  much  of  the  disorder  in  the  functions  of  the  brain,  which  so  constantly 
accompanies  deranged  action  of  the  digestive  system,  is  due  to  the  less  severe 
operation  of  the  same  cause ;  namely,  the  partial  retention  within  the  blood  of 
certain  constituents  of  the  bile,  which  should  have  been  eliminated  from  the 
circulating  fluid.  Such  an  abnormal  accumulation,  which  may  depend  either  on 
a  deficiency  in  the  functional  activity  of  the  liver,  or  on  an  excess  of  the  excre- 
mentitious  matters  brought  to  it  for  elimination,  is  habitual  in  some  persons; 
and  it  produces  a  degree  of  indisposition  to  bodily  or  mental  exertion  which  it 
is  difficult  to  counteract.  More,  probably,  is  to  be  gained  in  such  cases  by  the 
regulation  of  the  diet,  especially  the  reduction  of  its  hydrocarbonaceous  compo- 
nents, and  by  active  exercise  (which,  by  augmenting  the  respiration,  will  pro- 
mote the  elimination  of  any  superfluity  of  this  kind  through  the  lungs),  than  by 
continually  inciting  the  liver  to  increased  functional  activity,  by  medicines  which 
have  a  special  power  of  temporarily  augmenting  its  energy. — The  reabsorption 
of  Bile  into  the  blood,  as  seen  in  ordinary  cases  of  jaundice  dependent  upon  the 
obstruction  of  the  biliary  ducts,  does  not  act  on  the  general  system  in  a  manner 
nearly  so  injurious  as  the  retention  of  the  matters  at  the  expense  of  which  it  is 
formed  has  been  shown  to  do;3  in  fact,  much  of  the  disturbance  which  then 
ensues  may  be  attributed  to  the  disorder  of  the  digestive  function,  which  is 
consequent  upon  the  stoppage  of  the  flow  of  bile  into  the  intestinal  canal  (§§  453, 
454).  And  when  it  is  further  remembered  that  the  greater  part  of  the  bile 
which  passes  into  the  intestinal  canal  is  ordinarily  destined  for  re-absorption 
(§  457),  it  seems  fair  to  conclude  that  the  matters  which  accumulate  in  the  blood 

1  See  Dr.  G.  Budd's  "Treatise  on  Diseases  of  the  Liver,"  2d  edit.  Chap.  ii.  sect.  1. 

2  See  Dr.  Alison  in  "Ed.  Med.  &  Surg.  Journ.,"  vol.  xliv. ;  and  Dr.  Budd,  Op.  Cit, 
Chap.  iii. — From  the  evidence  collected  by  Dr.  Budd,  he  is  led  to  think  it  probable  that 
the  cerebral  symptoms  are  not  due  to  the  simple  retention  of  the  materials  of  Bile ;  but 
depend^ipon  some  metamorphosis  which  these  undergo  whilst  circulating  with  the  blood, 
whereby  a  more  noxious  poison  is  generated.     For  the  general  symptoms  of  suppressed 
secretion  may  have  shown  themselves  for  some  time,  before  any  serious  disturbance  occurs 
in  the  cerebral  functions ;  and  this  may  supervene  very  suddenly,  and  be  fatal  in  a  few 
hours  (p.  263).     The  analogy  of  Uraemia  (g  637)  seems  to  afford  some  confirmation  to  this 
view ;  but  it  must  be  borne  in  mind,  as  a  possible  explanation  of  the  phenomena,  and  one 
which  has  evidence  in  its  favor,  that  the  kidneys,  by  a  vicarious  action,  remove  the  most 
poisonous  of  the  retained  biliary  matters ;  and  that  it  is  only  when  they  can  no  longer  effect 
this,  that  the  results  of  the  accumulation  of  these  matters  begin  to  show  themselves  in  the 
perversion  of  the  functions  of  the  nervous  centres. 

3  Dr.  Budd  mentions  several  cases  (Op.  cit.,  pp.  209-227)  in  which  the  passage  of  bile 
into  the  intestines  was  entirely  prevented  by  the  complete  closure  of  the  ductus  communis, 
and  in  which,  nevertheless,  life  was  prolonged  for  many  months ;  in  one  of  these  cases,  the 
jaundice  first  occurred  in  a  woman  four  months  pregnant,  who  nevertheless  bore  a  living 
child  at  the  full  period,  and  suckled  it  up  to  the  time  of  her  death,  which  happened  when 
the  child  was  three  months  old. — In  all  these  cases,  death  seemed  to  result  from  gradual 
exhaustion,  consequent  upon  the  imperfect  assimilation  of  food,  rather  than  from  any 
toxic  agency ;  and  this  even  when  the  liver  was  in  such  a  state  of  disorganization,  that  its 
functional  activity  must  have  been  suspended  for  some  time  before  death. 


THE  LIVER.  —  SECRETION    OF  BILE.  593 

when  the  secreting  action  of  the  liver  is  suspended,  are  not  in  the  same  condition 
with  those  which  are  received  back  into  it  after  being  submitted  to  that  action ; 
and  that  the  liver,  therefore,  not  merely  separates  them,  but  exercises  a  certain 
transforming  agency  upon  them,  as  it  is.  known  to  effect  upon  other  constituents 
of  the  blood  which  pass  through  it  (§  472). 

632.  Bile  is  a  viscid,  somewhat  oily-looking  liquid,  of  a  greenish-yellow  color, 
and  very  bitter  taste,  followed  by  a  sweetish  after-taste.  It  is  readily  miscible 
with  water,  and  its  solution  froths  like  one  of  soap.  The  proportion  of  solid 
matter  which  it  contains  is  usually  from  9  to  12  per  cent. ;  and  nearly  the  whole 
of  this  consists  of  substances  peculiar  to  Bile. — The  following  are  the  general 
results  of  the  analyses  made  by  Berzelius,  of  Human  Bile,  and  of  that  of  the 
Ox:— 

MAN.  Ox. 

Water.       .  ,-,    •;  .-,-:-.  .^...^    .v  •-•-.'..,  v^l  :       .     90.44  92.84 

Biliary  matter       .         .        -    „ .-.    .-4*   •;         •       8.00  5.00 

Mucus  of  the  gall-bladder     .         .         .        ,'          ..       .30  .23 

Soda 41 

Chloride  of  sodium,  and  extractive         .         '.'.*  /  '*         .74  1.50 

Phosphates  and  sulphates  of  soda  and  lime   .         .         .11  .43 


100.00          100.00 

In  the  Biliary  matter,  according  to  the  researches  of  Strecker  (which  are  un- 
doubtedly the  most  accurate  and  satisfactory  that  have  been  hitherto  made),  the 
following  substances  may  be  distinguished :  Glycocholic  acid  (the  cholic  of 
Strecker  and  of  many  former  authors),  which  is  its  principal  organic  constitu- 
ent, united  for  the  most  part  with  soda,  but  with  small  and  variable  quantities 
of  potash  and  ammonia  (§  68); — Taurocholic  acid  (the  choleic  acid  of  Strecker, 
also  known  as  bilin),  which  also  is  united  with  alkaline  bases  (§  69) ; —  Choles- 
terin (§  43),  the  proportion  of  which  in  healthy  bile  is  usually  very  small; — 
and  Bile-pigments  (§  70),  of  which  also  the  proportion  is  usually  small.  It  is 
remarkable  that,  notwithstanding  the  comparatively  minute  proportion  in  which 
these  two  last  substances  exist  in  ordinary  bile,  Cholesterin  should  usually  be 
the  principal  ingredient  of  the  biliary  concretions  which  are  frequently  found 
in  the  gall-bladder  and  bile-ducts ;  and  that  the  bile-pigment  should  also  occasion- 
ally accumulate,  so  as  to  form  solid  masses  which  consist  of  little  else.1  It 
would  appear  from  this  that  the  peculiar  resinous  acids  of  the  bile  are  far  more 
readily  re-absorbed  than  are  its  other  ingredients;  and  this  corresponds  with 
the  results  of  experiments  upon  the  contents  of  the  alimentary  canal,  which 
show  that,  whilst  the  color  of  the  feces  is  chiefly  due  to  the  presence  of  bile- 
pigment,  the  conjugated  acids  are  scarcely  to  be  recognized. — The  quantity  of 
Bile  ordinarily  secreted  by  the  liver,  the  circumstances  which  favor  or  retard 
its  production,  the  mode  in  which  it  is  discharged  into  the  intestine,  and  the 
purposes  which  it  answers  in  the  digestive  process,  have  all  been  considered  in 
a  previous  chapter  (§§  453,  454) ;  and  it  now  only  remains  to  point  out,  that 
the  fact  of  the  performance  of  this  operation  during  foetal  life,  as  shown  by  the 
accumulation  of  biliary  matter  in  the  intestinal  canal  at  birth  (§  629),  is  a  clear 
indication  of  the  truly  excrementitious  matter  of  this  product.  Its  separation 
from  the  blood  during  intra-uterine  life  can  have  no  reference  to  the  process  of 
digestion,  which  is  not  then  taking  place;  nor  can  it  be  subservient  to  that  of 
respiration,  which  has  not  commenced ;  but  it  must  be  regarded,  like  the  elimi- 

1  The  cholesterin  and  bile-pigment  (which  forms  a  definite  compound  with  lime)  are 
held  in  solution  in  healthy  bile  by  the  tauro-cholic  acid.  Hence  it  seems  likely  that  the 
production  of  the  biliary  concretions  which  are  composed  of  these  substances,  is  due  either 
to  a  relative  deficiency  of  tauro-cholic  acid,  or  to  a  decomposition  of  that  substance  in  the 
gall-bladder. 

38 


594  OF    SECRETION   AND    EXCRETION. 

nation  of  urea,  as  a  necessary  means  of  removing  from  the  blood  those  products 
of  the  disintegration  of  the  tissues,  which  are  taken  back  into  the  circulation 
even  when  the  life  of  the  being  is  most  purely  vegetative ;  and  this  neces- 
sity arises  from  that  limitation  to  the  existence  of  each  individual  part,  which 
is  most  remarkable  when  the  processes  of  growth  and  development  are  taking 
place  with  the  greatest  rapidity. 

633.  If,  now,  we  bring  together  all  the  facts  at  present  known,  with  regard 
to  the  actions  performed  by  the  Liver,  they  appear  to  justify  the  following  con- 
clusions with  respect  to  its  offices. — 1.  That  the  Liver  is  essentially  an  organ 
of  excretion,  designed  to  remove  from  the  Blood  those  hydrocarbonaceous  pror 
ducts  of  the  disintegration  of  the  tissues,  which  cannot  be  converted  into  sugar 
or  fat  so  as  to  be  prepared  for  direct  elimination  by  the  respiratory  organs.     2. 
That  in  doing  this,  it  converts  these  excrementitious  matters  into  the  glyco- 
cholic  and  tauro-cholic  acids;  substances  which  have  a  certain  utility  in  the 
digestive  process,  and  which,  after  ministering  to  that  function,  are  capable  of 
being  reabsorbed,  and  of  undergoing  oxidation;  whereby  the  greater  part  of 
their  components  are  carried  off  in  the  form  of  carbonic  acid  and  water  by  the 
lungs,  the  remainder  (chiefly  the  alkaline  bases,  with  the  sulphur  of  the  taurine, 
which  is  converted  into  sulphuric  acid)  being  eliminated  by  the  kidneys. — 3. 
That  not  only  by  the  separation  of  biliary  matter  from  the  blood  and  by  the 
operation  of  this  upon  the  alimentary  substances,  but  also  by  the  change  in  the 
constituents  of  the  blood  itself,  the  Liver  aids  in  preparing  materials  for  the 
combustive  process.     For  it  converts  all  forms  of  saccharine  matter  derived  from 
the  food  into  "  liver-sugar,"  the  form  which  is  most  favorable  to  oxidation ;  and 
it  would  seem  capable  also  of  generating  this  sugar  from  protein-compounds,  or 
from  certain  products  of  their  decomposition  (§  46).     And  it  exercises  a  similar 
transforming  power  upon  fatty  matter;  generating  the  peculiar  " liver-fat," 
either  from  other  oleaginous  or  from  saccharine  substances  supplied  by  the  food, 
or,  as  it  would  also  appear,  from  protein-compounds,  or  from  the  products  of  the 
early  stages  of  their  retrograde  metamorphosis  (§  40). — In  all  the  foregoing 
actions,  the  Liver  is  subservient  to  the  Respiratory  function ;  but  in  a  mode 
very  different  from  that  formerly  propounded  by  Prof.  Liebig,1  who  represent- 
ed the  Liver  as  destined  to  prepare  by  secretion  the  materials  adapted  for  the 
sustenance  of  the  combustive  operation.     For  it  is  quite  certain  that  if  the 
whole  of  the  solid  biliary  matter  poured  into  the  intestine  were  reabsorbed,  it 
could  furnish  but  a  small  proportion  (probably  not  more  than  one-twelfth)  of 
the  total  amount  of  hydrocarbon  which  is  eliminated  by  the  lungs ;  and  the  pre- 
paration of  the  liver-sugar  and  liver-fat  in  the  blood  itself  is  evidently  the  far 
more  important  part  of  the  office  of  the  Liver  as  regards  the  Respiratory  func- 
tion.— 4.  But  the  Liver  also  aids,  if  the  statements  of  M.  Bernard  on  this  point 
be  correct,  in  the  assimilation  of  the  histogenetic  materials,  which  have  been 
newly  absorbed  from  the  digestive  cavity ;  the  raw  albumen  being  converted  by 
its  means  into  a  form  more  suitable  for  transmission  through  the  system  in  the 
current  of  the  circulation,  and  even  fibrin  being  generated  at  its  expense  (§§  167, 
169).     It  must  be  admitted,  however,  that  there  are  many  points  in  the  func- 
tion as  well  as  in  the  structure  of  the  Liver  which  still  remain  to  be  cleared  up. 

3. —  The  Kidneys. — Secretion  of  Urine. 

634.  The  Kidneys  cannot  be  regarded  as  inferior  in  importance  to  the  Liver, 
when  considered  merely  as  excreting  organs ;  but  their  function  only  consists 
in  separating  from  the  blood  certain  effete  substances  which  are  to  be  thrown  off 
from  it,  and  has  no  direct  connection  with  any  of  the  nutritive  operations  con- 

1  "Chemistry  applied  to  Animal  Physiology,"  1842. 


THE    KIDNEYS. SECRETION    OF   URINE. 


595 


cerned  in  the  introduction  of  aliment  into  the  system.  The  following  are  the 
points  in  the  minute  structure  of  these  organs  which  are  of  most  importance  in 
their  Physiological  relations.1  The  distinction  between  the  cortical  and  medul- 
lary parts  of  the  Kidney  essentially  consists  in  this — that  the  former  is  by  far 
the  most  vascular,  and  the  plexus  formed  by  the  tubuli  uriniferi  seems  to  come 
into  the  closest  relation  with  that  of  the  sanguiferous  capillaries,  so  that  it  is 
probably  the  seat  of  the  greater  part  of  the  process  of  secretion ;  whilst  the 
latter  is  principally  composed  of  tubes,  passing  in  a  straight  line  from  the  for- 
mer towards  their  point  of  entrance  into  the  ureter.  The  adjoining  figure  (Fig. 
163)  represents  the  appearance  presented  by  a  portion  of  an  injected  Kidney,  as 
seen  by  the  naked  eye,  and  under  a  low  magnifying  power.  The  tubuli  urini- 
feri, in  passing  outwards  from  the  calices,  increase  in  number  by  divarication 
to  a  considerable  extent,  as  shown  in  Fig.  165,  but  their  diameter  remains  the 
same.  When  they  arrive  in  the  cortical  substance,  their  previously  straight 
direction  is  departed  from,  and  they  become  much  convoluted.  The  closeness 
of  the  texture  formed  by  their  interlacement  with  the  bloodvessels  renders  it 

Fig.  164. 


Portion  of  the  Kidney  of  a  new-born  infant : — A, 
natural  size ;  a,  a,  Corpora  Malpighiana,  as  dispersed 
points  in  the  cortical  substance;  b,  papilla. — B,  a 
smaller  part  magnified ;  a,  a,  Corpora  Malpighiana ; 
b,  tubuli  uriniferi. 


Portion  of  one  of  the  tubuli  uriniferi,  from  the 
kidney  of  an  adult ;  showing  its  tesselated  epithe- 
lium. 


difficult  to  obtain  a  clear  view  of  their  mode  of  termination;  but  they  seem  to 
inosculate  with  each  other,  so  as  to  form  a  plexus,  with  free  extremities  here 
and  there  (Fig.  165);  the  number  of  these  free  extremities,  however,  does  not 
appear  to  be  nearly  equal  to  that  of  the  uriniferous  tubes  themselves.3  The 
tubuli  are  lined  with  an  epithelium,  the  cells  of  which  are  irregularly  roundish 
or  polyhedral  in  form  (Fig.  164);  each  cell  contains  a  nucleus;  and  in  its  inte- 

1  See  especially  Mr.  Bowman's  Memoir  in  the  "Philosophical  Transactions,"  1842; 
also  Goodsir  in  "Edinb.  Monthly  Journal,"  1842  ;  Gerlach,  Bidder,  and  Kolliker,  in  "  Miil- 
ler's  Archiv.,"  1845;  Toynbeein  "Med.-Chir.  Trans.,"  1846;  Johnson  in  "  Cyclop,  of  Anat. 
and  Phys.,"  art.  "Ren.;"  Gairdner  in  "Edinb.   Monthly  Journal,"  1848;  and  Frerichs, 
"Die  Bright' sche  Nierenkrankheit  und  deren  Behandlung,"  1851. 

2  In  Mr.  Bowman's  opinion,  all  the  free  extremities  of  the  tubuli  uriniferi  include  Cor- 
pora Malpighiana ;  and  the  appearance  of  csecal  terminations,  such  as  those  represented 
at  1  and  3,  Fig.  165,  he  regards  as  an  optical  illusion,  caused  by  a  change  in  the  direction 
of  the  tubuli.  which  occasions  them  to  dip  away  suddenly  from  the  observer. 


596 


OF   SECRETION   AND   EXCRETION 


rior  there  is  ordinarily  to  be  seen  a  little  finely  granular  matter,  with  a  few 
minute  fat-globules  clustered  round  the  nucleus.  The  cell-wall  is  remarkable 
for  its  delicacy,  and  is  one  of  the  first  structures  to  undergo  decomposition ;  and 

Fig.  165. 


A  small  portion  of  the  Kidney,  magnified  about  60  times  :  1,  supposed  csecal  extremity  of  a  tulmlus  urini- 
fcrus;  2,  2,  recurrent  loops  of  tubuli;  3,  3,  bifurcations  of  tubuli;  4,  5,  6,  tubuli  converging  towards  the 
papilla:  7,  7,  7,  Corpora  Malpighiana,  eeen  to  consist  of  convoluted  knots  of  bloodvessels,  connected  with  a 
capillary  network ;  8,  arterial  trunk. 


THE   KIDNEYS. SECRETION   OF   URINE. 


597 


Fig.  166. 


after  its  destruction,  free  nuclei,  interspersed  among  amorphous  granules,  alone 
remain  in  the  interior  of  the  tubules.  The  epithelial  cells  are  arranged  more 
or  less  regularly  on  the  interior  of  the  basement-membrane,  in  such  a  manner 
that  a  free  channel  is  left  in  the  centre  of  each  tubule. — Scattered  through  the 
plexus  formed  by  the  bloodvessels  and  uriniferous  tubes,  a  number  of  little 
dark  points  may  be  seen  with  the  naked  eye,  to  which  the  designation  of  Cor- 
pora Malpighiana  has  been  given,  after  the  name 
of  their  discoverer.  Each  one  of  these,  when  ex- 
amined with  a  high  magnifying  power,  is  found  to 
consist  of  a  convoluted  mass  of  minute  blood- 
vessels (Fig.  165,  7);  and  this  is  included  in  a 
flask-like  dilatation  of  one  of  the  tubuli  uriniferi 
(Fig.  166).  According  to  Mr.  Bowman,  this 
dilatation  proceeds  only  from  the  termination  of  the 
tubulus ;  and  this  seems  to  be  usually  the  case, 
although  it  seems  not  improbable  that  it  may  some- 
times be  a  lateral  diverticulum,  as  described  by 
Gerlach  (loc.  cit.).  The  epithelium,  which  else- 
where lines  the  tube,  is  altered  in  appearance 
where  the  tube  is  continuous  with  this  capsular 
dilatation  (Fig.  166,  &')j  being  there  more  trans- 
parent and  furnished  with  cilia  (as  shown  at  b"), 
which  in  the  Frog  may  be  seen  for  many  hours 
after  death,  in  very  active  motion,  directing  a  cur- 
rent down  the  tube.  Further  within  the  capsule, 
this  epithelium  becomes  excessively  delicate,  and 
sometimes  disappears  altogether.  The  surface  of 
the  Malpighian  tuft  is  often  seen  to  be  studded  with 
nuclear  particles,  which  suggest  the  idea  that  it  is 
covered  by  an  epithelial  layer }  and  hence  G-erlach, 
followed  by  other  anatomists,  has  maintained  that 
the  flask-shaped  dilatation  of  the  tubulus  uriniferus 
is  not  perforated  by  the  bloodvessels  which  form  the 
Malpighian  tuft,  but  is  reflected  over  it.  It  appears 
probable,  however,  that  these  nuclear  particles 
really  belong  to  the  walls  of  the  vessels ;  and  the 
most  careful  examination  has  failed  to  detect  any 
such  reflexion.  On  this  as  on  all  other  points  of 
importance,  therefore,  Mr.  Bowman's  original  description  proves  to  be  unas- 
sailable.1 

635.  The  Circulation  of  Blood  through  the  Kidney  presents  a  very  remark- 
able peculiarity.  The  supply  is  derived  in  Man  (as  in  other  Mammalia)  direct 
from  the  arterial  system ;  though  in  Fishes  and  Reptiles,  the  urinary  apparatus 
is  connected,  as  well  as  the  biliary,  with  the  portal  venous  system,  and  even 
in  Birds  a  portion  of  its  blood  is  derived  from  the  latter.  But  although  this 
organ  is  supplied  from  the  renal  artery,  yet  it  is  not  to  its  proper  secretory  appa- 
ratus that  the  blood  of  that  artery  is  distributed  in  the  first  instance ;  for,  on  enter- 
ing the  kidney,  this  vessel  speedily  and  entirely  divides  itself  into  minute  twigs, 
which  are  the  afferent  vessels  of  the  Malpighian  tufts  (Fig.  167,  of).  After 
it  has  pierced  the  capsule,  each  twig  dilates  ;  and  suddenly  divides  and  subdi- 

1  The  a  priori  improbability  that  the  basement-membrane  of  a  glandular  tubule  or  follicle 
should  be  thus  penetrated  by  bloodvessels,  has  been  entirely  removed  by  the  discovery  that 
such  penetration  does  take  place  in  other  cases,  as  the  Peyerian  glandulse  ($  456)  and  the 
Corpora  Malpighiana  of  the  Spleen  (§  482). 


Uriniferous  Tube,  Malpighian 
Tuft,  and  Capsule,  from  Kidney  of 
Frog: — a,  cavity  of  the  tube;  6, 
epithelium  of  the  tube;  6',  ciliated 
epithelium  of  the  neck  of  the  cap- 
sule; 6",  detached  epithelium-scale; 
c,  basement-membrane  of  tube;  c'' 
basement-membrane  of  capsule ;  m, 
convoluted  capillaries  of  the  Mal- 
pighian tuft. 


OF   SECRETION   AND   EXCRETION. 


Fig.  167. 


vides  itself  into  several  minute  branches,  terminating  in  convoluted  capillaries, 
which  are  collected  in  the  form  of  a  ball  (m,  m) ;  and  from  the  interior  of  the 
ball,  the  solitary  efferent  vessel,  e  /,  arises,  which  passes  out  of  the  capsule  by 
the  side  of  the  single  afferent  vessel.  This  ball  seems  to  lie  loose  and  bare  in 
the  capsule,  being  attached  to  it  only  by  its  afferent  and  efferent  vessels  (Fig. 
166,  m).  The  efferent  vessels,  on  leaving  the  Malpighian  bodies,  separately 
enter  the  plexus  of  capillaries,  p,  surrounding  the  tubuli  uriniferi,  st,  and  supply 
that  plexus  with  blood ;  from  this  plexus  the  renal  vein  arises. — Thus  there  is 
a  striking  analogy  between  the  mode  in  which  the  tubuli  uriniferi  are  supplied 
with  blood,  for  the  purpose  of  elaborating  their  secretion,  and  the  plan  on  which 
the  hepatic  circulation  is  carried  on.  For  as  the  secretion  of  the  Liver  is  formed 
from  blood  conveyed  to  it  by  one  large  vessel,  the  vena  portae,  which  has  col- 
lected it  from  the  venous  capillaries  of  the  chylopoietic  viscera,  and  which  sub- 
divides again  to  distribute  it  through  the  liver,  so  the  secretion  of  the  Kidney 
is  elaborated  from  blood  which  has  already  passed  through  one  set  of  capillary 
vessels,  those  of  the  Malpighian  tufts;  this  blood  is 
collected  and  conveyed  to  the  proper  secreting  surface, 
however,  not  by  one  large  trunk  (which  would  have 
been  a  very  inconvenient  arrangement),  but  by  a  mul- 
titude of  small  ones,  the  efferent  vessels  of  the  Mal- 
pighian bodies,  which  may  be  regarded  as  collectively 
representing  the  vena  portse,  since  they  convey  the  blood 
from  the  systemic  to  the  secreting  capillaries.  Hence 
the  Kidney  may  be  said  to  have  a  portal  system  within 
itself. — This  ingenious  view  of  Mr.  Bowman's  finds 
support  from  the  fact  that  in  Reptiles  the  efferent  ves- 
sels of  the  Malpighian  bodies  (which  receive  their  blood, 
as  elsewhere,  from  the  renal  artery)  unite  with  the 
branches  of  the  vena  portaa,  to  form  the  secreting  plexus 
around  the  tubuli  uriniferi.  Here,  therefore,  the 
blood  of  the  secreting  plexus  has  a  double  source,  the 
vessels  which  supply  it  receiving  their  blood  in  part 
from  the  capillaries  of  the  organ  itself,  and  in  part 
from  those  of  viscera  external  to  it;  just  as,  in  the 
Liver,  the  secreting  plexus  is  supplied  in  part  by  the 
nutritive  capillaries  of  the  organ  itself,  which  receive 
their  blood  from  the  hepatic  artery,  and  in  part  by  the 
blood  conveyed  from  the  chylopoietic  viscera  through 
the  vena  portae. 

636.  These  admirable  researches  of  Mr.  Bowman  on  the  structure  of  the  Mal- 
pighian bodies,  and  on  the  vascular  apparatus  of  the  Kidney,  have  thrown  great 
light  upon  the  mode  in  which  the  Urinary  secretion  is  elaborated.  One  of  the 
most  remarkable  circumstances  attending  this  excretion,  in  the  Mammalia  par- 
ticularly, is  the  large  but  variable  quantity  of  water  which  is  thus  got  rid  of — 
the  amount  of  which  bears  no  constant  proportion  to  that  of  the  solid  matter 
dissolved  in  it.  The  Kidneys,  in  fact,  seem  to  form  a  kind  of  regulating  valve, 
by  which  the  quantity  of  water  in  the  system  is  kept  to  its  proper  amount. 
The  amount  of  exhalation  from  the  Skin,  which,  with  that  from  the  Lungs,  is 
the  other  principal  means  of  removing  superfluous  liquid  from  the  blood,  is  liable 
to  be  greatly  affected  by  the  temperature  and  degree  of  humidity  of  the  air 
around  (§  647)  :  hence,  if  there  were  not  some  other  means  of  adjusting  the 
quantity  of  fluid  in  the  bloodvessels,  it  would  be  subject  to  continual  and  very 
injurious  variation.  This  important  function  is  performed  by  the  Kidneys; 
which  allow  such  a  quantity  of  water  to  pass  into  the  urinary  tubes,  as  may  keep 
the  pressure  within  the  vessels  at  a  nearly  uniform  standard.  The  quantity  of 


Distribution  of  the  Renal  ves- 
sels ;  from  Kidney  of  Horse : — a, 
branch  of  Renal  artery :  a/,  af- 
ferent vessel ;  m,  m,  Malpighian 
tufts ;  ef,  ef,  efferent  vessels ;  p, 
vascular  plexus  surrounding 
the  tubes ;  st,  straight  tube ;  ct, 
convoluted  tube. 


THE   KIDNEYS.  —  SECRETION   OF   URINE.  599 

water  which  is  passed  off  by  the  Kidneys,  therefore,  will  depend  in  part  upon 
that  exhaled  by  the  Skin ;  being  greatest  when  this  is  least,  and  vice  versa :  but 
the  quantity  of  solid  matter  to  be  conveyed  away  in  the  secretion  has  little  to 
do  with  this  ;  being  dependent  upon  the  amount  of  waste  in  the  system,  and  upon 
the  quantity  of  surplus  azotized  aliment  which  has  to  be  discharged  through  this 
channel. — The  Kidney  contains  two  very  distinct  provisions  for  these  purposes. 
The  cells  lining  the  tubuli  uriniferi  are  probably  here,  as  elsewhere,  the  instru- 
ments by  which  the  solid  matter  of  the  secretion  is  elaborated;  whilst  it  can 
scarcely  be  doubted  that  the  office  of  the  Corpora  Malpighiana  is  to  allow  the 
transudation  of  the  superfluous  fluid  through  the  thin-walled  and  naked  capilla- 
ries of  which  they  are  composed.  "  It  would  indeed,"  Mr.  Bowman  remarks 
(Op.  cit.,  p.  75),  "be  difficult  to  conceive  a  disposition  of  parts  more  calculated 
to  favor  the  escape  of  water  from  the  blood  than  that  of  the  Malpighian  body. 
A  large  artery  breaks  up  in  a  very  direct  manner  into  a  number  of  minute 
branches;  each  of  which  suddenly  opens  into  an  assemblage  of  vessels  of  far 
greater  aggregate  capacity  than  itself,  and  from  which  there  is  but  one  narrow 
exit.  Hence  must  arise  a  very  abrupt  retardation  in  the  velocity  of  the  current 
of  blood.  The  vessels  in  which  this  delay  occurs  are  uncovered  by  any  structure. 
They  lie  bare  in  a  cell,  from  which  there  is  but  one  outlet,  the  orifice  of  the 
tube.  This  orifice  is  encircled  by  cilia,  in  active  motion,  directing  a  current 
towards  the  tube.  These  exquisite  organs  must  not  only  serve  to  carry  forward 
the  fluid  which  is  already  in  the  cell,  and  in  which  the  vascular  tuft  is  bathed ; 
but  must  tend  to  remove  pressure  from  the  free  surface  of  the  vessels,  and  so 
to  encourage  the  escape  of  their  more  fluid  contents." — Here  we  see  the  essential 
difference  which  exists  between  the  vital  agency  concerned  in  the  true  Secreting 
process,  and  the  physical  power  which  occasions  fluid  exhalation  or  transudation. 
This  difference  is  precisely  the  same  as  that  which  exists  between  the  vital  act 
of  selective  absorption,  and  the  physical  operation  of  endosmose  or  imbibition. 
By  Imbibition  and  Transudation,  certain  fluids  may  pass  through  organic  mem- 
branes, in  the  dead  as  well  as  in  the  living  body;  and  this  passage  depends 
merely  upon  the  physical  condition  of  the  part,  in  regard  to  the  amount  and  the 
nature  of  the  fluid  it  .contains,  and  the  permeability  of  its  tissues.  Not  only 
does  water  thus  transude,  but  various  substances  that  are  held  in  complete  solu- 
tion in  it,  especially  albuminous  and  saline  matter  :  it  is  in  this  manner  that  the 
Blood  absorbs  fluids  from  the  digestive  cavity  (§  464),  and  pours  out  the  serous 
fluid  which  occupies  the  interspaces  of  the  areolar  tissue  and  the  serous  cavities. 
The  transudation  of  the  watery  portion  of  the  blood  is  much  increased  by  any 
impediment  to  its  flow  through  the  vessels,  and  also  by  any  causes  that  produce 
a  diminished  resistance  in  their  walls. 

637.  The  nature  and  purposes  of  the  Urinary  secretion,  and  the  alterations 
which  it  is  liable  to  undergo  in  various  conditions  of  the  system,  are  much  better 
understood  than  are  those  of  the  Bile;  this  is  owing,  in  great  part,  to  the  two 
circumstances,  that  it  may  be  readily  collected  in  a  state  of  purity,  and  that  its 
ingredients  are  of  such  a  nature  as  to  be  easily  and  definitely  separated  from  each 
other  by  simple  chemical  means.  There  can  be  no  doubt  that  the  chief  purpose 
of  this  excretion  is  to  remove  from  the  system  the  effete  azotized  matters,  which 
the  blood  takes  up  in  the  course  of  the  circulation,  or  which  may  have  been 
produced  by  changes  occurring  in  itself.  This  is  evident  from  the  large  propor- 
tion of  Nitrogen  contained  in  the  solid  matter  dissolved  in  it;  and  from  the 
crystalline  form  presented  by  much  of  this  solid  matter  when  separated — a  form 
which  indicates  that  its  state  of  combination  is  such,  as  to  prevent  it  from  con- 
ducing to  the  nutrition  of  the  system.  The  injurious  effects  of  the  retention  of 
the  components  of  the  Urinary  secretion  in  the  Blood  are  fully  demonstrated 
by  the  results  of  its  cessation ;  whether  this  be  made  to  take  place  experiment- 
ally (as  by  tying  the  renal  artery),  or  be  the  consequence  of  a  disordered  condi- 


600  OP   SECRETION   AND   EXCRETION. 

tion  of  the  kidney.  The  symptoms  of  Uraemia  (as  this  condition  has  been 
appropriately  termed)  are  altogether  such  as  indicate  the  action  of  a  specific 
poison  upon  the  Nervous  system;  affecting  either  the  Brain  or  the  Spinal  Cord 
separately,  or  both  together.  In  the  first  form,  a  state  of  stupor  comes  on  rather 
suddenly,  out  of  which  the  patient  is  with  difficulty  aroused ;  and  this  gradually 
deepens  into  complete  coma,  with  fixed  pupils  and  stertorous  breathing,  just  as 
in  ordinary  kinds  of  narcotic  poisoning.  In  the  second  form,  convulsions  of  an 
epileptic  character,  frequently  affecting  the  whole  muscular  system,  suddenly 
occur;  but  there  is  no  loss  of  consciousness.  In  the  third  form,  coma  and  con- 
vulsions are  combined.  It  has  been  generally  supposed  that  these  results  are 
attributable  to  the  accumulation  of  urea  in  the  blood ;  but  clinical  observation 
affords  sufficient  evidence,  that  there  is  no  constant  relation  between  the  severity 
of  these  symptoms  and  the  amount  of  urea  in  the  circulating  system;1  and  expe- 
riment has  determined  that  the  other  constituents  of  the  urine  do  not  exert  any 
more  potent  influence.3  It  seems  probable,  then,  that  some  substance  formed 
at  the  expense  of  the  normal  constituents  of  urine,  rather  than  either  of  these 
substances  themselves,  is  the  real  poisonous  agent  in  cases  of  Uraemia ;  and  very 
cogent  evidence  has  been  adduced  by  Prof.  Frerichs,  in  proof  of  his  idea  that 
the  symptoms  of  this  disorder  arise  from  the  conversion  of  the  Urea  in  the  cir- 
culating current  into  Carbonate  of  Ammonia,  by  the  agency  of  a  suitable  ferment ; 
so  that,  however  great  may  be  the  accumulation,  it  does  not  give  rise  to  any 
serious  consequences,  unless  this  ferment  be  also  present.  Two  series  of  experi- 
ments are  described  by  him  as  supporting  this  doctrine;  the  first  showing  that 
in  cases  of  uraemic  intoxication,  a  resolution  of  urea  into  carbonate  of  ammonia 
is  actually  taking  place,  ammonia  being  found  in  the  expired  air  when  the  first 
symptoms  make  their  appearance,  and  in  the  blood  and  in  the  contents  of  the 
stomach  after  death;  and  the  second  proving  that  the  injection  of  carbonate  of 
ammonia  into  the  circulating  current  induces  a  train  of  symptoms  essentially 
corresponding  with  those  of  uraemia,  stupor  and  convulsions  occurring  either 
separately  or  conjointly.3 — It  seems  not  improbable  that,  as  in  the  case  of  the 
retention  of  Bile  in  the  Blood  (§  631),  many  of  the  minor  as  well  as  of  the 
severer  forms  of  sympathetic  disturbance,  connected  with  disordered  secretion 
from  the  kidney,  are  due  to  this  directly  poisonous  operation  of  the  decomposing 
constituents  of  the  urine,  upon  the  several  organs  whose  function  is  disturbed ; 
and  that  many  complaints,  in  which  no  such  agency  has  been  until  recently 
suspected — especially  Convulsive  affections  arising  from  a  disordered  action  of 
the  nervous  centres — are  thus  due  to  the  insufficient  elimination  of  Urea  from 
the  Blood.4 

638.  In  order  to  form  a  correct  opinion  of  the  state  of  the  Urinary  secretion 
in  morbid  conditions  of  the  system,  it  is  desirable  to  be  acquainted  with  every 
leading  particular  regarding  its  normal  character. — Fresh  healthy  Urine  is  a 
perfectly  transparent,  amber-yellow-colored  liquid,  exhaling  a  peculiar  but  not 
disagreeable  odor,  and  having  a  bitterish  saline  taste.  In  all  natural  conditions 
of  the  Human  system  (even  when  a  vegetable  diet  is  used),  the  urine  possesses 

1  It  has  been  remarked  by  Bright,  Christison,  G.  0.  Rees,  and  Frerichs,  that  urea  may 
often  be  obtained  in  considerable  quantity  from  the  blood  of  patients  suflFering  under 
"Bright's  disease,"  who  were  at  the  same  time  free  from  all  nervous  symptoms. 

2  Thus  Frerichs  (as  Bichat,  Courten,  and  Gaspard  had  before  done)  repeatedly  injected 
from  20  to  40  grammes  of  filtered  human  urine,  sometimes  even  with  the  addition  of  urea, 
into  the  veins  of  animals,  without  any  ill  effects  resulting. 

3  On  this  subject,  the  chapter  on  "  Uraemia"  in  the  admirable  treatise  of  Frerichs  "Die 
Bright' sche  Nierenkrankheit  und  dcren  Behandlung,"  should  be  especially  consulted. 

4  Of  the  truth  of  this  view,  which  was  propounded  by  the  Author  in  the  first  edition  of 
this  work,  many  illustrations  have  been  since  afforded ;   among  the  most  interesting  of 
which,  is  the  very  frequent  coincidence  of  "  Bright's  disease"  with  Puerperal  Convulsions, 
first  pointed  out  by  Dr.  Lever. 


THE   KIDNEYS.  —  SECRETION   OP   URINE.  601 

a  well-marked  acid  reaction.  When  it  is  left  to  itself  for  some  time,  slight 
nebulae,  consisting  of  mucus,  are  formed  in  it;  and  these  gradually  descend  to 
the  bottom.  Soon  afterwards,  an  unpleasant  odor  is  developed;  instead  of  an 
acid,  an  alkaline  reaction  is  presented,  in  consequence  of  the  decomposition  of 
the  urea  into  carbonate  of  ammonia;  and  a  precipitation  of  earthy  phosphates 
then  takes  place.  A  turbidity  may  occur,  however,  on  the  simple  cooling  of 
the  urine,  without  any  such  departure  from  its  normal  composition  as  would 
properly  constitute  disease ;  this  being  due  to  the  precipitation  of  urates  of  soda 
and  ammonia,  under  the  conditions  formerly  specified  (§  56).  If  the  urine  be 
turbid,  however,  when  it  is  passed  from  the  body,  having  a  temperature  of  98° 
or  100°,  it  must  be  considered  as  abnormal.  The  average  Quantity  of  urine 
passed  during  the  24  hours,  has  been  variously  estimated :  it  differs,  of  course, 
with  the  amount  of  fluid  ingested,  and  it  is  influenced  also  by  the  external  tem- 
perature ;  a  much  smaller  amount  of  the  superfluous  fluid  of  the  body  being  set 
free  from  the  skin  in  winter  than  in  summer,  and  a  larger  proportion  being  car- 
ried off  by  the  kidneys.  Probably  we  shall  be  pretty  near  the  truth,  in  estimat- 
ing the  amount  (with  Dr.  Prout)  at  from  about  30  oz.  in  summer,  to  40  oz.  in 
winter,  for  a  person  who  does  not  drink  more  than  the  simple  wants  of  nature 
require. — The  Specific  Gravity  comes  to  be  a  very  important  character,  in  various 
morbid  conditions  of  the  urine :  and  it  is  therefore  desirable  to  estimate  it  cor- 
rectly. This  also  is  liable,  of  course,  to  the  same  causes  of  variation;  since, 
when  the  same  amount  of  solid  matter  is  dissolved  in  a  larger  or  smaller  quantity 
of  water,  the  specific  gravity  will  be  proportionably  lower  or  higher.  The  ave- 
rage, according  to  Dr.  Prout,  in  a  healthy  person,  taking  the  whole  year  round, 
is  about  1020;  the  standard  rising  in  summer  (on  account  of  the  greater  dis- 
charge of  fluid  by  perspiration)  to  1025 ;  and  being  lowered  in  winter  to  1015. 
Simon,  however,  states  the  average  specific  gravity  at  no  more  than  1012.  It 
will  depend,  in  each  individual  Case,  upon  the  amount  of  fluid  habitually  ingested, 
as  compared  with  that  dissipated  by  cutaneous  exhalation ;  and  it  will  also  vary 
with  the  period  that  has  elapsed  since  the  last  introduction  of  liquid  into  the 
stomach.  From  these  and  other  causes,  the  proportion  of  solid  matter  in  1000 
parts  of  Urine  may  vary  from  20  to  70;  and  hence  the  various  recorded  analyses 
of  this  liquid  present  very  wide  diversities  in  the  proportions  of  its  solid  consti- 
tuents. These  discrepancies,  however,  being  chiefly  due  to  the  fluctuating  amount 
of  water,  become  very  much  less  (as  Simon1  pointed  out)  when  we  calculate  the 
proportion  which  each  principal  component  bears  to  100  of  solid  residue;  as  is 
shown  in  the  following  Table : — • 

Berzelius.  Lehmann.  Simon.  Marchand. 

Urea          ....                  .     45.10        49.68  33.80        48.91 

Uric  Acid          ...                  .       1.50          1.61  1.40           1.59 

Extractive  matter,  Ammonia-sa  ts,  \      qfi  qn         9o  Qr  A<>  «n         <?9  4Q 

and  Chloride  of  Sodium                  >     36'30         28'95  42'60         32'49 


Alkaline  Sulphates 
Alkaline  Phosphates 


10.30        11.58          8.14         10.18 
6.88          5.96  6.50          4.57 


Phosphates  of  Lime  and  Magnesia    .       1.50          1.97  1.59  1.81 

We  shall  presently  find  the  causes  of  some  of  the  variations  even  here  shown, 
to  lie  in  the  nature  of  the  ingesta,  and  in  the  amount  of  exercise  taken  by  the 
individual. 

639.  The  most  important  of  those  organic  constituents  of  the  Urine,  whose 
presence  may  be  directly  traced  to  the  metamorphosis  of  the  azotized  components 
of  the  tissues  and  of  the  blood,  is  evidently  that  which,  from  its  being  the  prin- 
cipal cause  of  the  characteristic  properties  of  the  secretion,  is  termed  Urea. 
This  substance,  as  already  shown  (§  52),  exists  preformed  in  the  Blood ;  being 

1  "Animal  Chemistry,"  translated  by  Dr.  Day,  p.  405,  Am.  Ed. 


602  OF   SECRETION   AND   EXCRETION. 

generated  by  the  retrograde  metamorphosis  of  Muscular  tissue  (probably  through 
the  intermediation  of  creatine  or  of  uric  acid),  and  also  by  similar  changes  in 
the  unassimilated  portions  of  the  Blood  itself.1 — The  amount  of  Urea  excreted 
in  the  24  hours  has  been  made  the  subject  of  examination  by  M.  Lecanu  :2  and 
the  following  are  his  results  as  deduced  from  a  series  of  120  analyses : — 

Minimum.  Mean.  Maximum. 

By  Men3     .         .         .         .         .     357.51  grs.  433.13  grs.  510.36  grs. 

By  Women          ....     153.25    "  295.15    "  437.06    " 

By  Old  Men  (84  to  86  years)      .       61.08    "  125.22    «  295.15    " 

By  Children  of  eight  years        .     161.78    "  207.99    "  254.20    " 

By  Children  of  four  years          .       57.28    "  69.55    "  81.83    " 

It  is  very  interesting  to  perceive,  in  this  table,  how  large  an  amount  of  Urea  is 
excreted  by  children  ;  and  how  small  a  quantity  in  proportion  to  their  bulk,  by 
old  men.  This  corresponds  precisely  with  the  rapidity  of  interstitial  change  at 
different  periods  of  life.  (See  CHAP.  in.  SECT.  3.)  The  quantity  of  Urea 
secreted  at  any  given  period  of  life  seems  to  depend  mainly  on  two  conditions ; 
namely,  the  degree  of  muscular  exertion  previously  put  forth,  and  the  amount 
of  azotized  matter  ingested  as  food.  Thus,  Prof.  Lehmann  ascertained  that,  by 
the  substitution  of  violent  for  moderate,  exercise,  the  quantity  of  Urea  was  raised 
from  82 \  to  45 \  parts;  and  Simon  found  that,  by  two  hours'  violent  exercise, 
the  proportion  of  the  urea  in  the  urine  passed  half  an  hour  subsequently,  was 
double  that  contained  in  the  morning  urine.  Again,  Prof.  Lehmann  has  shown 
that  the  amount  of  Urea  excreted  daily,  when  no  azotized  matter  was  taken  in 
as  food,  and  when  the  excretion  was  simply  a  measure  of  the  "waste"  of  the 
tissues,  was  not  above  half  that  excreted  when  an  ordinary  mixed  diet  was  em- 
ployed, and  only  about  two-sevenths  of  that  which  was  passed  when  the  diet  was 
purely  animal.  The  recent  experiments  of  Prof.  Bischof  are  to  the  same  effect  ; 
for  he  found  that  a  large  dog  secreted,  with  mixed  food,  from  230  to  300  grains 
of  urea  daily;  with  flesh  diet,  802  grains;  and  when  fed  on  intestines  and  gela- 
tine, no  less  than  1110  grains  daily.  This  last  statement  confirms  the  inference 
to  which  the  injection  of  a  solution  of  Gelatin  directly  into  the  blood  appears  to 
lead  (§  399);  namely,  that  urea  may  be  formed  directly  from  the  metamorphosis 

1  A  new  and  easy  method  of  determining  the  amount  of  Urea  in  Urine  has  lately  been 
introduced  by  Prof.  Liebig.     It  is  founded  on  the  fact  that  urea  forms  with  pernitrate  of 
mercury  two  compounds,  one  with  2,  the  other  with  4  equivs.  of  peroxide  of  mercury.  The 
latter  is  almost  insoluble ;  and  therefore,  by  adding  to  urine  pernitrate  of  mercury,  from 
a  solution  of  known  strength,  the  urea  may  be  precipitated  and  its  quantity  determined 
in  a  few  minutes.     All  the  phosphoric  acid  in  the  urine,  however,  must  first  have  been 
precipitated  by  barytes ;  which  will  also,  of  course,  throw  down  its  sulphuric  acid.     The 
presence  of  a  chloride  prevents  the  action  of  the  pernitrate  on  the  urea,  converting  it  into 
a  perchloride ;  hence  the  chloride  of  sodium  always  contained  in  the  Urine  must  be  allowed 
for,  before  the  quantity  of  Urea  can  be  determined.     The  appearance  of  the  precipitate 
shows  when  all  the  chlorine  present  has  been  taken  into  combination  with  the  mercury ;  so 
that  the  quantity  of  the  pernitrate  added  to  produce  it  gives  that  of  the  common  Salt, 
while  the  quantity  afterwards  required  to  throw  down  the  whole  Urea  gives  the  amount  of 
that  substance.     (See  Prof.  Gregory's  "Handbook  of  Organic  Chemistry,"  p.  509;  and 
Dr.  Martin  Barry's  communication  in  the  "  Lancet,"  April  17,  1852.) 

2  "Journal  de  Pharmacie,"  torn.  xxv. 

3  According  to  Prof.  Bischof,  of  Giessen,  who  has  employed  Prof.  Liebig's  method  of  esti- 
mating the  amount  of  urea  in  Urine  (described  in  the  preceding  note),  the  quantity  ordi- 
narily excreted  daily  by  a  healthy  man  is  not  less  than  830  grains,  or  nearly  12  ounces 
avoirdupois.     If  this  be  correct,  the  estimates  of  Lecanu  are  far  below  the  truth,  his  mean 
for  men  being  only  433  grains,  or  little  more  than  half  the  estimate  of  Bischof.     Still  the 
above  table  will  have  a  certain-  value ;  since  all  the  amounts  stated  in  it  were  obtained  by 
the  same  method,  and  may  therefore  be  fairly  compared  with  each  other.     The  speedy 
publication  of  Prof.   Liebig's  process  "in  a  form  adapted  for  easy  and  accurate  use  by 
medical  men"  has  been  promised ;  and  it  is  to  be  hoped  that  a  large  body  of  valuable  facts 
will  then  be  collected. 


THE   KIDNEYS. — SECRETION   OF   URINE.  603 

of  this  substance,  and  probably,  therefore,  from  the  disintegration  of  the  gela- 
tigenous  as  well  as  of  the  albuminous  tissues.  Next  in  importance  to  urea, 
among  the  organic  products  of  the  metamorphosis  of  the  azotized  constituents 
of  the  tissues  or  of  the  blood,  but  ordinarily  bearing  a  very  small  proportion  to 
it  in  quantity,  is  Uric  acid.  It  has  been  shown  (§  57)  that  the  formation  of 
this  substance  is  probably  anterior  to  that  of  urea;  and  we  shall  see  that  its 
proportion  in  the  urine  is  augmented  under  the  same  conditions  as  regards  food 
(§  640).  On  the  other  hand,  there  is  reason  to  think  that  exercise,  by  augment- 
ing the  respiration,  tends  to  dimmish  the  proportion  of  uric  acid  in  the  urine, 
by  converting  it  into  urea.  The  circumstances  that  most  favor  the  genesis  of 
uric  acid  in  the  system,  therefore,  and  its  increased  proportion  in  the  urine  if 
there  be  no  obstacle  to  its  elimination,  are  a  highly  azotized  diet  and  inactive 
habits ;  whilst  the  reduction  of  the  azotized  portion  of  the  diet  to  what  is  really 
wanted  for  the  nutrition  of  the  system,  and  the  promotion  of  the  respiration  by 
active  exercise,  tend  to  the  reduction  of  the  proportion  of  this  component.  The 
precipitation  of  uric  acid  (usually  in  combination  with  alkaline  bases),  which 
frequently  takes  place  on  the  cooling  of  the  urine,  must  not  be  regarded  as  in- 
dicative of  the  presence  of  an  unusual  amount  of  this  substance  ;  since  it  may 
depend  upon  a  variety  of  other  conditions  (§  56).  There  are  many  diseases, 
however,  especially  those  of  a  febrile  nature,  in  which  the  presence  of  an  excess 
of  uric  acid  is  a  very  marked  symptom;  there  is  usually,  at  the  same  time,  a 
reduction  in  the  proportion  of  urea;  and  thus  it  would  seem  that,  with  perhaps 
an  augmented  tendency  to  disintegration  of  the  tissues,  there  is  an  incapacity 
for  the  performance  of  that  higher  process  of  oxidation  which  is  requisite  for 
the  genesis  of  urea;  so  that  a  larger  proportion  of  the  products  of  the  "waste" 
passes  off  in  the  state  of  uric  acid,  as  in  animals  whose  respiration  is  feeble. 
This  view  derives  support  from  the  fact  that  Hippuric  acid,  which  is  only  to 
be  found  in  extremely  minute  proportion  in  healthy  Human  urine,  and  the  com- 
position of  which  indicates  that  it  is  to  be  regarded  as  a  result  of  very  imper- 
fect oxidation  (§§  58,  59),  undergoes  a  marked  increase  under  the  same  circum- 
stances, and  especially  when  obstructed  action  exists  in  either  of  the  other  great 
emunctories,  the  lungs,  liver,  or  skin,  so  that  a  larger  amount  of  carbonaceous 
matter  is  thrown  upon  the  kidneys  for  elimination ;  for  in  this  case,  also,  there 
is  a  deficiency  in  the  normal  amount  of  urea.  Although  the  presence  of  Crea- 
tine  and  Creatinine  in  the  Urine,  the  former  in  very  small  proportion,  but  the 
latter  in  considerably  larger  amount,  is  now  a  well-established  fact,  the  actual 
quantities  ordinarily  excreted,  and  the  circumstances  which  favor  their  increase 
and  diminution,  have  not  yet  been  determined.  From  the  considerations  for- 
merly adduced  (§§  60,  61),  it  seems  likely  that  Creatine  is  one  of  the  first  pro- 
ducts of  the  disintegration  of  muscular  tissue,  and  that  a  portion  of  the  urea 
eliminated  in  the  urine,  as  well  as  of  the  greater  part  (if  not  the  whole)  of  the 
Creatinine,  is  generated  at  its  expense.  The  presence  of  Lactic  acid  in  the 
Urine,  although  by  no  means  infrequent,  must  be  regarded  as  exceptional.  We 
have  seen  that  a  constant  genesis  of  this  substance  is  taking  place  in  the  body, 
not  merely  as  a  product  of  the  metamorphosis  of  the  saccharine  matters  em- 
ployed as  food,  but  also  as  one  of  the  results  of  the  disintegration  of  the  azotized 
tissues  (§§  48-50);  but  that  the  respiratory  process  affords  the  ordinary  channel 
for  its  removal;  so  that  it  is  only  when  its  production  is  excessive,  or  when 
there  is  some  obstruction  to  its  elimination  by  the  lungs,  that  it  makes  its  ap- 
pearance in  the  urine.  These  conditions  are  so  often  present  in  disease,  that 
Lactic  acid  is  far  more  commonly  present  in  abnormal  than  in  normal  states  of 
the  secretion.  The  Extractive  Matters  of  the  Urine,  as  already  pointed  out 
(§  64),  are  made  up  of  a  variety  of  different  compounds,  our  knowledge  of  which 
is  gradually  being  extended.  Among  the  substances  which  rank  under  this  head 
in  the  ordinary  analyses  of  Urine,  are  ^creatine,  creatinine,  and  hippuric  acid ; 


604  OP   SECRETION   AND   EXCRETION. 

and  others  are  being  successively  determined.  Thus  Stadeler  has  shown  that 
the  "  extractive"  of  the  Urine  of  the  Cow  contains  a  peculiar  azotized  compound, 
and  several  volatile  non-azotized  acids,  analogous  to,  and  in  one  instance  abso- 
lutely identical  with,  the  products  of  the  imperfect  oxidation  of  wood  or  coal.1 
And  Prof.  Ronalds  has  shown  that  the  "  extractive"  of  Human  urine  ordinarily 
contains  a  sulphurized  and  a  phosphorized  compound,  which  serve  for  the  excre- 
tion of  sulphur  and  phosphorus  in  an  unoxidized  state.2  The  Urine- Pigment, 
again,  has  been  to  a  certain  extent  separated  as  a  definite  compound  from  the  "ex- 
tractive," especially  by  the  researches  of  Heller  (§  64).  On  the  whole,  we  may 
say  that  with  the  exception  of  Creatine  and  Creatinine,  all  the  known  consti- 
tuents of  the  "  Urinary  extractive"  are  substances  which  are  rich  in  carbon  and 
comparatively  poor  in  nitrogen ;  so  that  their  increase  will  be  favored  by  an  ex- 
cess of  carbonaceous  food,  an  imperfect  action  of  the  liver,  and  a  low  degree  of 
respiration;3  whilst,  on  the  other  hand,  a  highly  azotized  diet,  especially  if  com- 
bined with  active  exercise,  will  tend  to  their  reduction.  This  view  is  confirmed 
by  the  results  of  Prof.  Lehmann's  experiments,  which  were  performed  with  a 
view  to  determine  the  influence  of  diet  upon  the  constitution  of  the  Urine. 

640.  In  the  first  series  of  these  experiments,  Prof.  Lehmann  adopted  an  ordi- 
nary mixed  diet ;  but  he  took  no  more  solid  or  liquid  aliment  than  was  needed 
to  appease  hunger  or  thirst,  and  abstained  from  fermented  drinks.  Every  two 
hours  he  took  exercise  in  the  open  air,  but  he  avoided  immoderate  exertion  of 
every  kind.  The  average  result  of  the  examination  of  the  Urine  passed  under 
these  circumstances,  for  fifteen  days,  is  given  in  the  first  line  of  the  subsequent 
table. — In  a  second  series  of  experiments,  Prof.  L.  lived  for  twelve  days  on 
an  exclusively  animal  diet ;  and  for  the  last  six  of  these,  it  consisted  solely  of 
eggs.  He  took  32  eggs  daily;  which  contained  2929  grains  of  dry  albumen, 
and  2431  grs.  of  fatty  matters;  or  about  3532  grs.  of  carbon,  and  465  J  grs.  of 
azote.  The  amount  of  Urea  is  shown,  in  the  second  line  of  the  table,  to  have 
undergone  a  very  large  increase ;  and  it  contained  more  than  five-sixths  of  the 
whole  azote  ingested. — In  a  third  series  of  experiments,  Dr.  L.  lived  for  twelve 
days  on  a  vegetable  diet;  and  its  efiect  upon  the  solid  matter  of  the  Urine  is 
shown  in  the  third  line  of  the  table. — In  a  fourth,  he  lived  for  two  days  upon 
an  unazotized  diet,  consisting  entirely  of  pure  farinaceous  and  oleaginous  sub- 
stances, so  that  the  azotized  matter  of  the  Urine  must  have  been  solely  the 
result  of  the  disintegration  of  the  tissues.  It  is  seen  to  undergo  a  very  marked 
diminution,  under  this  regimen;  as  is  shown  in  the  fourth  line  of  the  table. 
His  health  was  so  seriously  affected,  however,  by  this  diet,  that  he  was  unable 
to  continue  it  longer. 


Extractive 
Solid  Matters.  Urea.  Uric  Acid.        Matters  and  Salts. 


I.  Mixed  diet     .         .  1047.14  grs.  501.76  grs.  18.26  grs.  196.65  grs. 

II.  Animal  diet  .         .  1350.07    "  821.37    "  22.82    "  112.89    " 

III.  Vegetable  diet        .  914.66    "  347.10    "  15.77    "  295.95    " 

IV.  Non-Azotized  diet  .  643.53    "  237.90    "  11.34    "  264.48    " 


1  See  Dr.  Gregory's  "Handbook  of  Organic  Chemistry,"  p.  450. 

2  See  "Philosophical  Transactions,"  1846,  pp.  461-464. 

3  This  is  particularly  obvious  in  cases  in  which  the  functions  of  the  Liver  are  imperfectly 
performed.     For  there  is  first  to  be  observed  an  increase  in  the  ordinary  Urine-pigment 
(which  contains  58£  per  cent,  of  carbon),  giving  a  high  color  to  the  secretion,  and  caus- 
ing the  addition  of  a  few  drops  of  hydrochloric  acid  to  the  warmed  fluid  to  develop  a  fine 
crimson  or  purple  hue.     If  the  inactivity  of  the  liver  increase,  a  deposit  of  purpurine  (a 
substance  which  contains  62*]  per  cent,  of  carbon)  is  thrown  down  ($  64).     And  the  com- 
plete arrest  of  the  elimination  of  bile  is  marked  by  the  appearance  of  the  proper  Bile- 
pigment  in  the  urine.     (See  Dr.  Golding  Bird's  "Lectures  on  Therapeutics,"  in  "Med. 
Gaz.,"  1848,  vol.  xlii.  p.  229.) 


THE    KIDNEYS.  —  SECRETION   OF   URINE.  605 

The  following  inferences  are  drawn  by  Prof.  Lehmann  from  these  experiments : — 
1.  Animal  articles  of  diet  augment  the  Solid  matters  of  the  Urine.  Vege- 
table substances,  and  still  more  such  as  are  deprived  of  azote,  on  the  contrary, 
diminish  it. — 2.  Although  Urea  is  a  product  of  decomposition  of  the  organism, 
yet  its  proportions  in  the  urine  depend  also  on  the  food,  for  we  find  that  a 
richly-azotized  diet  considerably  augments  its  quantity.  In  the  above  experi- 
ments, the  proportion  of  the  Urea  to  the  other  solid  matters  was  as  100  to  116 
on  a  mixed  diet;  as  100  to  63  on  an  animal  diet ;  as  100  to  156  on  a 
vegetable  diet;  and  as  100  to  170  on  a  non-azotized  diet. — 3.  The  quantity  of 
Uric  acid  depends  less  on  the  nature  of  the  diet  than  on  other  circumstances ; 
the  differences  observed  in  it  being  too  slight  to  warrant  us  in  ascribing 
them  to  the  former  cause. — 4.  The  Protein-compounds,  and  consequently  the 
azote  of  the  food,  are  absorbed  in  the  intestinal  canal ;  and  what  is  not  employ- 
ed in  the  formation  of  the  tissues,  is  thrown  off  by  the  Kidneys  in  the  form  of 
Urea  or  Uric  acid ;  these  organs  being  the  chief,  if  not  the  sole  channel  through 
which  the  system  frees  itself  of  its  excess  of  azote. — 5.  The  urine  contains  quan- 
tities of  Sulphates  and  Phosphates  proportional  to  the  azotized  matters  which 
have  been  absorbed;  and  the  proportion  of  these  salts  is  sensibly  increased  under 
the  use  of  a  large  amount  of  those  substances. — 6.  In  the  same  circumstances, 
the  Extractive  matters  diminish,  while  their  quantity  is  increased  by  the  use  of 
vegetable  diet;  a  fact  which  proves  the  influence  of  vegetable  aliment  over  the 
production  of  these  matters  in  the  urine. — 7.  The  urine,  after  the  use  of  animal 
food,  has  a  strong  acid  reaction,  but  contains  little  or  no  lactic  acid  and  no  hip- 
puric  acid.  Under  a  vegetable  diet  there  is  more  lactic  acid,  but  it  is  united  to 
bases.  The  largest  production  of  lactic  acid  is  under  a  non-azotized  diet ;  and 
most  of  it  is  then  combined  with  ammonia.  Therefore  the  lactic  acid  eliminated 
with  the  urine  is  in  great  part  the  product  of  non-azotized  substances  not 
entirely  assimilated;  but  it  results  also  in  part  from  the  decomposition  of  the 
azotized  substances  entering  into  the  composition  of  the  body  and  the  food. — 8. 
The  Kidneys  not  only  separate  certain  constituent  parts  of  the  organs  which 
have  become  inadequate  for  the  maintenance  of  life,  but  they  also  expel  the 
superfluous  nutritive  matters  that  may  have  been  absorbed.1 

641.  Besides  its  organic  materials,  the  Urine  contains  a  considerable  amount 
of  /Saline  matter;  the  excretion  of  which,  in  a  state  of  solution,  appears  to  be 
one  of  the  principal  offices  of  the  Kidney.  Various  saline  compounds  are 
continually  being  introduced  with  the  food ;  and  others  are  formed  within 
the  system,  by  the  oxidation  of  the  Sulphur  and  Phosphorus  of  the  tissues 
or  of  the  food,  and  by  the  combination  of  the  sulphuric  and  phosphoric 
acids  thus  formed,  with  alkaline  and  earthy  bases  which  the  food  may  con- 
tain, usually  in  a  state  of  combination  with  weaker  acids  which  are  otherwise 
disposed  of.  Thus  the  Saline  compounds  found  in  the  urine  are  to  be  regarded 
as  partly  proceeding  from  the  retrograde  metamorphosis  of  the  materials  of  the 
tissues,  after  these  have  served  their  purpose  in  the  economy,  and  partly  from 
that  of  such  components  of  the  food,  as,  being  superfluous,  do  not  undergo 
organization.  But  the  Kidney  also  serves  as  the  channel  for  the  elimination  of 
saline  compounds  introduced  into  the  system  per  se;  these  being  sometimes 
normally  present  in  the  body,  but  ingested  in  too  large  an  amount,  as  is  often 
the  case  with  common  Salt;  whilst,  on  the  other  hand,  they  may  be  altogether 
foreign  to  the  composition  alike  of  its  solids  and  its  fluids.— The  Alkaline  Sul- 
2)hates  usually  constitute,  as  we  have  seen  (§  638),  about  10  per  cent,  of  the 
whole  solid  matter  of  the  Urine.  Being  always  in  solution,  however,  they 
never  make  their  presence  known  by  the  formation  of  sediments,  and  are  only 

1  "Journ.  fur  praktische  Chemie,"  1842-3;  see  also  ''Simon's  Animal  Chemistry," 
translated  by  Dr.  Day,  pp.  414-420,  Am.  Ed. ;  and  Prof.  Lehmann's  "Lehrbuch  der  Phy-* 
siologischen  Chemie,"  band  ii.  p.  447. 


606  OF    SECRETION    AND    EXCRETION. 

to  be  detected  by  chemical  tests.  The  causes  which  influence  their  amount 
have  been  carefully  studied  by  Dr.  Bence  Jones;  who  has  shown  that  they  vary 
(like  urea)  with  the  amount  of  food  ingested,  and  with  the  degree  of  nervo- 
muscular  activity  put  forth;  as  might  be  anticipated  from  the  fact  that,  under 
ordinary  circumstances,  the  sulphuric  acid  is  entirely  formed  within  the  system, 
by  the  oxidation  of  the  sulphur  of  the  protein-compounds,  the  bases  being  fur- 
nished by  the  alkaline  carbonates  or  phosphates  of  the  blood,  whose  source  has 
been  already  considered  (§  83).  When  sulphuric  acid  or  soluble  sulphates  are 
taken  into  the  system  per  se,  they  partly  find  their  way  out  of  it  by  the  Kidneys 
(§  88) ;  the  proportion  of  sulphuric  acid  in  the  urine  being  for  a  time  augment- 
ed, although  the  increase  is  not  considerable  until  some  hours  have  elapsed  after 
the  introduction  of  these  substances  into  the  stomach.1 — The  amount  of  Alka- 
line Phosphates  (§  84)  in  the  Urine  is  usually  about  half  that  of  the  alkaline 
sulphates.  The  acid  of  these  also  is  ordinarily  generated  within  the  system  by 
the  oxidation  of  the  phosphorus  originally  introduced  in  the  protein-compounds; 
and  thus,  as  in  the  case  of  the  sulphates,  the  quantity  of  them  which  is  excreted. 
by  the  urine  bears  a  certain  relation  to  the  amount  of  these  compounds  ingested 
as  food,  and  also  to  the  amount  of  muscular  tissue  which  has  undergone  disinte- 
gration by  exercise.  But  it  further  appears  that  there  is  a  special  relation 
between  the  quantity  of  the  alkaline  phosphates  in  the  urine,  and  the  amount 
of  disintegration  of  the  nervous  tissue  (§  361) ;  as  might  have  been  suspected 
from  the  fact  that  this  tissue  is  distinguished  by  the  very  large  proportion  of 
phosphorus,  united  with  fatty  acids,  which  it  contains  (§  345).  And  a  marked 
increase  of  these  salts  is  observed  in  those  inflammatory  diseases  of  the  brain, 
in  which  there  is  reason  to  believe  that  an  unusually  rapid  disintegration  of  its 
texture  is  taking  place.3 — The  Earthy  Phosphates  usually  bear  but  a  small 
proportion  to  the  Alkaline ;  but  their  presence  in  the  urine  comes  to  be  of  great 
importance,  with  reference  to  the  precipitates  which  they  form  in  particular 
conditions  of  that  secretion.  From  the  researches  of  Dr.  Bence  Jones  (loc.  cit.) 
it  appears  that  the  quantity  of  these  phosphates  in  the  urine  chiefly  varies  with 
the  amount  of  them  contained  in  the  food,  into  many  articles  of  which  they 
enter  largely  (§§  76,  78);  but  he  has  also  ascertained  that  their  formation 
within  the  system  is  determined  by  the  presence  of  their  bases ;  for,  if  any 
earthy  salt,  a  little  chloride  of  calcium  or  sulphate  of  magnesia  for  instance,  be 
taken  into  the  system,  the  quantity  of  earthy  phosphates  in  the  urine  undergoes 
an  increase.  The  small  quantity  of  carbonate  of  lime  taken  into  the  system 
with  the  food  (§  77),  or  set  free  by  the  slow  disintegration  of  the  osseous  tissue, 
is  probably  excreted  in  Man  almost  entirely  in  the  form  of  phosphate  ;  although 
of  the  much  larger  amount  ingested  by  herbivorous  animals,  a  considerable  pro- 
portion is  excreted  in  the  urine  in  its  original  state.  The  Earthy  Phosphates, 
although  insoluble  in  water,  are  soluble  in  all  acid  liquids;  and  they  are  held  in 
solution  in  Urine,  like  the  urates,  by  the  acid  phosphate  of  soda.  Their  preci- 
pitation in  an'  alkaline  state  of  the  urine  is  owing  to  the  want  of  this  solvent, 
not  to  an  excess  in  their  production ;  for,  as  Dr.  Bence  Jones  has  pointed  out, 
that  excess  of  alkaline  and  earthy  phosphates  in  the  urine  which  constitutes  the 
true  "phosphatic  diathesis,"  is  generally  coincident  with  a  highly  acid  state  of 
the  urine. — The  only  other  inorganic  saline  constituent  of  the  Urine  whose 

1  Dr.  Bence  Jones  in  "Philosophical  Transactions,"  1849. 

2  See  Dr.  Bence  Jones's  valuable  series  of  papers  in  the  "Philosophical  Transactions" 
for  1845,  1847,  and  1850,  and  in  the  "  Medico-Chirurgical  Transactions"  for  1847   arid 
1850.     It  is  curious  to  observe  that,  whilst  the  increase  in  the  alkaline  phosphates  in  In- 
flammatory affections  of  the  nervous  centres  is  very  marked,  there  appears  to  be  a  posi- 
tive diminution  of  them  in  Delirium  Tremens.     A  certain  allowance  must  be  made,  how- 
ever, for  the  abstinence  from  food,  which  will  of  itself  occasion  a  reduction  in  the  quantity 
excreted. 


THE   KIDNEYS.  —  SECRETION    OP   URINE.  607 

quantity  gives  it  importance  is  Chloride  of  Sodium.  By  far  the  larger  pro- 
portion of  this  is  doubtless  derived  directly  from  the  food;  but  little  being 
furnished  by  the  disintegration  of  Muscle,  which  will  set  free  potash  rather  than 
soda  (§  307).  The  amount  eliminated  by  the  urine  is  consequently  subject  to 
great  variation,  it  being  the  function  of  the  Kidneys  to  remove  whatever  is 
superfluous,  so  as  to  prevent  the  blood  from  becoming  overcharged  with  this 
substance  (§  82).  Of  the  chloride  of  sodium  introduced  as  food,  a  part  appears 
to  undergo  decomposition  in  the  system,  whereby  hydrochloric  acid  is  furnished 
to  the  gastric  fluid,  and  soda  to  the  bile ;  part  of  this  acid,  however,  must  re- 
unite with  its  base  in  the  alimentary  canal,  so  that  the  chloride  of  sodium  thus 
regenerated  will  be  absorbed  with  the  products  of  the  digestive  operation. — 
Although  Nitric  Acid  cannot  be  regarded  as  a  normal  constituent  of  the  Urine, 
yet  the  recent  investigations  of  Dr.  Bence  Jones1  show  that  it  is  formed  by  a  com- 
bustive  process  within  the  body,  whenever  ammoniacal  salts  are  introduced  into 
the  system ;  its  amount,  however,  being  very  small.  He  has  also  found  that  it 
is  generated  after  the  ingestion  of  small  quantities  of  urea;  a  fact  which  affords 
some  confirmation  to  the  doctrine  of  Frerichs  (§  637),  that  urea  may  undergo 
decomposition  into  carbonate  of  ammonia,  whilst  still  circulating  in  the  current 
of  blood. — The  presence  of  Oxalic  Acid  in  the  urine  (in  combination  with  Lime) 
has  been  usually  regarded  as  a  pathological  phenomenon,  consequent  upon  an 
irregular  performance  of  the  retrograde  metamorphosis  of  the  tissues ;  but 
there  can  be  no  doubt  that  it  may  also  result  from  the  presence  of  soluble  salts 
of  oxalic  acid  in  certain  articles  of  vegetable  food.3 

642.  The  ordinary  acid  reaction  of  the  Urine  appears  to  be  due,  not  to  the 
presence  of  any  free  acid,  but  to  the  conversion  of  the  basic  phosphate  of  soda 
into  the  acid  phosphate,  by  the  subtraction  of  a  part  of  the  base,  which  occurs 
when  uric,  hippuric,  lactic  or  other  free  acids  come  into  contact  with  the 
former  substance.  There  is  no  adequate  reason  to  believe  that,  in  the  healthy 
state,  there  is  ever  any  other  cause  than  this  ;  although  in  morbid  urine,  free  or- 
ganic acids  are  almost  certainly  present.3  It  has  been  shown  by  the  researches  of 
Dr.  Bence  Jones,  however,  that  the  acid  reaction  is  far  from  being  constant  in 
its  degree,  even  when  an  ordinary  mixed  diet  is  steadily  employed ;  for  that  it 
varies  at  different  periods  of  the  day,  increasing  and  decreasing  inversely  with 
the  acidity  of  the  stomach  (§  443).  Thus  the  acidity  of  the  Urine  decreases 
soon  after  taking  food,  whilst  that  of  the  Stomach  is  increasing ;  and  attains 
its  lowest  limit  from  three  to  five  hours  after  a  meal,  frequently  giving  place  to 
an  alkaline  reaction.  The  acidity  then  gradually  increases,  whilst  that  of  the 
stomach  is  decreasing ;  and  attains  its  highest  limit  after  a  fast  of  some  hours, 
when  the  stomach  is  quite  empty,  and  its  secretion  neutral.  If  no  food  be 
taken,  the  acidity  does  not  decrease,  but  remains  at  nearly  the  same  point  for 
ten  or  twelve  hours.  When  animal  food  was  alone  employed,  the  diminution 
of  the  acidity  after  a  meal  was  more  marked,  and  continued  longer,  than  when 
a  mixed  diet  was  eaten  (apparently  on  account  of  the  greater  demand  for  acid 
in  the  stomach) ;  and  the  acidity  did  not  rise  quite  so  high  after  fasting,  as  with 
a  mixed  diet.  On  the  other  hand,  when  the  diet  was  purely  vegetable,  the 
diminution  of  its  acidity  was  never  such  as  to  render  the  urine  absolutely  alka- 
line, although  its  acidity  was  reduced  to  the  point  of  neutrality  ;  and  the  increase 
of  its  acidity  after  fasting  was  sometimes  very  considerable,  though  by  no  means 
so  marked  as  the  decrease  of  alkalescence. — These  diurnal  variations  in  the 
acidity  of  the  urine  make  it  highly  probable  that  corresponding  variations  occur 
in  the  alkalescence  of  the  blood ;  such  diurnal  variations  being  produced  by  the 

1  "Philosophical  Transactions,"  1851. 

2  See  Dr.  Golding  Bird  on  "Urinary  Deposits,"  2d  Am.  Ed.,  p.  188. 

3  See  Prof.  Lehmann's  "Lehrbuch  der  Physiologischen  Chemie,"  band  ii.pp.  398-400. 


608  OP    SECRETION    AND    EXCRETION. 

quantity  of  acid  separated  from  it,  and  poured  into  the  stomach  for  the  purpose 
of  dissolving  the  food.  The  introduction  of  dilute  sulphuric  acid  into  the 
stomach,  even  in  large  doses,  was  not  found  to  produce  any  decided  change  in 
the  acidity  of  the  urine ;  the  only  perceptible  effect  being  a  slight  diminution 
of  the  decrease  which  takes  place  after  taking  food,  and  a  slight  augmentation 
of  the  increase  after  fasting.  On  the  other  hand,  the  use  of  liquor  potassae  in 
large  doses  lessens  the  acidity  of  the  urine,  preventing  it  from  rising  after  fast- 
ing to  the  height  it  would  otherwise  attain,  and  increasing  its  alkalescence  after 
a  meal ;  but  it  does  not  render  the  urine  by  any  means  constantly  alkaline,  nor 
does  it  hinder  the  variations  produced  by  the  state  of  the  stomach  from  being 
very  evident.  Tartaric  acid,  in  large  doses,  increases  the  acidity  of  the  urine, 
causing  it  to  rise  considerably  higher  than  usual  after  a  fast,  but  not  preventing 
that  which  is  passed  a  few  hours  after  food  from  becoming  alkaline.  Tartrate 
of  potash  in  large  doses,  on  the  other  hand,  has  a  marked  effect  in  rendering 
the  urine  alkalescent ;  still,  it  does  not  prevent  the  usual  recurrence  of  the 
acidity  some  hours  after  a  meal.1 

643.  It  seems  to  have  been  clearly  proved  by  Dr.  Bence  Jones  (loc.  cit.), 
that  there  is  no  relation  whatever  between  the  acidity  of  the  urine  and  the 
absolute  amount  of  Uric  acid  which  it  may  contain ;  for  in  the  urine  which  is 
most  acid,  and  which  deposits  the  largest  uric-acid  sediment,  very  little  uric 
acid  may  really  exist ;  whilst  that  which  contains  most  uric  acid  may  hold  it  in 
perfect  solution,  and  may  have  but  a  feeble  acid  reaction.3 — The  main  cause  of 
the  deposit  of  Uric-acid  sediments  is  doubtless  the  presence  of  some  other  acid ; 
for  the  addition  of  any  acid  to  healthy  urine  passed  soon  after  food  is  always 
sufficient  to  produce  it.     But  the  deposit  takes  place  less  readily  if  the  temper- 
ature of  the  fluid  be  high,  since  the  solvent  power  of  the  acid  phosphate  of  soda 
is  then  more  strongly  exerted ;  so,  on   the  other  hand,  a  deposit  often  takes 
place  in  urine  which  would  not  otherwise  exhibit  it,  through  an  unusual  reduc- 
tion in  its  temperature,  as  by  exposure  to  the  cold  air  of  a  sleeping-room  in  the 
winter.     Again,  the  deposit  of  uric-acid  sediment  is  favored  by  concentration  of 
the  liquid,  which  thus  augments  the  proportion  of  the  urate  to  the  water,  and  at 
the  same  time  increases  the  acid  reaction ;  and  thus  urine  whose  constituents 
are  otherwise  normal  may  throw  down  a  copious  deposit  of  this  kind,  merely 
from  deficiency  of  water ;  whilst  an  unusual  amount  of  uric  acid  may  be  really 
present  without  being  deposited — the  urine,  too,  possessing  its  ordinary  acidity 
— if  the  proportion  of  water  be  large.    Thus  the  uric  sediment  may  be  regarded 
as  dependent  upon  three  concurrent  conditions  :  (1)  Decrease  of  temperature ; 
.(2)  Increased  proportion  of  uric  acid  compound  to  the  water,  positively  or  rela- 
tively ;  (3)  Increased  acidity  of  the  urine.     Sometimes  one  condition  is  most 
influential,  sometimes  another ;  but  they  are  all  usually  concerned  in  some  de- 
gree. 

644,  The  Urine  of  Herbivorous  animals  is  almost  invariably  alkaline;  partly 
because  their  food  contains  a  large  quantity  of  alkaline  and  earthy  bases,  in 
combination  with  citric,  tartaric,  oxalic,  and  other  acids,  which  are  decomposed 
within  the  system  (§  83);  and  partly  because  the  amount  of  sulphuric  and 
phosphoric  acids,  generated  as  products  of  the  oxidation  of  the  elements  of  the 
tissues  or  of  the  surplus  food,  is  not  sufficient  to  neutralize  them.     Such  is  the 
condition  which  occasions  the  alkalinity  of  Human  Urine,  when  a  portion  of 

1  See  Dr.  Benee  Jopes's  "Contributions  to  the  Chemistry  of  the  Urine,"  in  "Philosophical 
Transactions,"  1849. 

2  It  will  be  remembered  that  these  sediments  nearly  always  consist  of  Uric  acid  in  union 
with  a  base  (§  56);  this  base  is  regarded  by  Prof.  Lehmann  as  chiefly  soda;   whilst  Dr. 
Bence  Jones,  in  common  with  Dr.  GoLding  Bird,  maintains  it  to  be  ammonia.     The  term 
"  uric-acid  sediment"  is  used  above  to  designate  this  compound,  whatever  maybe  the  sub- 
Stance  with  which  the  uric  acid  is  united. 


THE   KIDNEYS.  —  SECRETION   OF   URINE.  609 

the  acid  which  would  otherwise  show  a  predominance,  is  directed  into  another 
channel ;  and  it  is  exaggerated  in  those  states  in  which,  either  from  the  irri- 
tating nature  of  the  food,  or  from  the  irritable  condition  of  the  stomach,  an 
undue  quantity  of  acid  is  poured  out  into  that  viscus  ;  so  that,  its  reaction  being 
habitually  acid,  that  of  the  urine  becomes  habitually  alkaline.  Such  a  state  of 
the  urine  must  be  carefully  distinguished,  as  Dr.  Bence  Jones  has  pointed  out,1 
from  that  in  which  the  alkalescence  is  due  to  the  presence  of  volatile,  and  not 
to  that  of  fixed  alkali ;  the  difference  being  easily  recognizable  by  the  influence 
of  the  liquid  upon  reddened  litmus-paper,  for  the  restoration  of  its  blue  color 
is  permanent  in  the  latter  case,  but  only  transitory  in  the  former.  The  alka- 
lescence due  to  the  presence  of  volatile  alkali  is  due  to  the  decomposition  of 
urea,  whilst  the  urine  is  yet  within  the  bladder,  through  the  agency  of  morbid 
secretions  of  that  viscus ;  and  it  disappears  when  this  organ  returns  to  its  healthy 
state.  On  the  other  hand,  the  alkalescence  from  fixed  alkali  proceeds  from 
disordered  action  of  the  stomach,  which  is  usually  connected  with  disorder  of 
the  general  system ;  and  it  persists  until  this  can  be  remedied.  In  both  forms 
of  alkalescence,  there  is  a  precipitation  of  earthy  phosphates ;  but  in  the  alka- 
lescence from  fixed  alkali,  the  precipitate  usually  consists  almost  entirely  of  phos- 
phate of  lime ;  whilst  in  that  from  volatile  alkali,  the  amorphous  sediment  of 
phosphate  of  lime  is  mingled  with  prismatic  crystals  of  the  phosphate  of  ammonia 
and  magnesia.  These  precipitates  may  be  obtained  from  healthy  urine,  by 
adding  to  it  a  solution  of  potash  or  of  ammonia ;  and  the  decomposition  of  such 
urine,  which  begins  to  take  place  very  soon  after  it  leaves  the  body,  gives  rise 
to  the  same  precipitation,  by  the  production  of  carbonate  of  ammonia  at  the 
expense  of  its  urea  (§  52). 

645.  Thus,  then,  we  have  seen  that  the  Kidneys  serve  as  the  special  instru- 
ments for  depurating  the  Blood  of  those  highly-azotized  compounds,  which  are 
formed  in  the  system  by  the  decomposition  of  the  materials  of  the  albuminous 
and  gelatinous  tissues,  and  also  by  that  of  the  non-assimilated  components  of  the 
food.  We  have  seen,  also,  that  they  serve  for  the  removal  of  certain  compounds 
of  which  carbon  is  a  principal  ingredient;  and  these,  although  normally  present 
in  but  small  amount,  may  undergo  a  marked  increase  in  disease,  especially  when 
the  liver  is  insufficiently  performing  its  functions,  or  the  respiratory  process  is 
obstructed.  Further,  we  have  been  led  to  regard  the  Kidneys  as  the  emunctory, 
not  only  for  the  superfluous  water  of  the  blood,  but  also  for  those  saline  com- 
pounds, which,  having  been  introduced  into  the  system,  or  generated  within  it, 
in  larger  amount  than  is  compatible  with  the  normal  constitution  of  the  blood, 
or  than  is  required  for  the  reparation  of  the  solids  of  the  body,  or  for  the  pro- 
duction of  its  fluid  secretions,  are  only  fitted  for  elimination.  And  this  state- 
ment is  to  be  extended  from  saline  compounds  to  such  other  soluble  matters 
as  are  not  removed  by  other  channels.  On  this  point  a  very  elaborate  series 
of  researches  was  made  by  Wb'hler,3  who  showed  that  of  the  soluble  salts  taken 
into  the  circulation,  those  are  most  readily  excreted  which  produce  a  determina- 
tion of  blood  towards  the  kidneys,  whereby  an  increased  quantity  of  liquid  is 
filtered  off  through  the  outlet  which  they  afford.  And  it  is  in  this  manner  that 
the  system  makes  an  effort  to  free  itself  (so  to  speak)  from  various  foreign  sub- 
stances which  have  been  introduced  into  it  by  absorption,  and  which  would  be 
injurious  if  retained;  the  rate  at  which  it  does  so  being  in  a  great  degree  depend- 
ent upon  the  functional  activity  of  the  Kidneys  (§§  89, 207,  208). — It  does  not 
appear,  however,  that  the  excretion  of  the  organic  compounds  which  are  formed 
within  the  system  is  augmented  by  those  "  diuretic"  medicines  which,  by  deter- 
mining an  increased  flow  of  blood  to  the  Kidneys,  cause  a  larger  amount  of  liquid 

1  "Medical  Times,"  Dec.  13,  1851. 

2  "Miiller's  Elements  of  Physiology,"  translated  by  Baly,  p.  589. 
39 


610 


OF   SECRETION   AND   EXCRETION. 


to  be  passed  off  through  them.  On  the  contrary,  it  would  seem  as  if,  by  pro- 
ducing congestion  and  irritation,  they  sometimes  interfered  with  the  normal 
process  of  secretion;  so  that  the  quantity  of  solid  constituents  is  actually  de- 
creased, notwithstanding  the  large  augmentation  in  the  watery  part  of  the  urine. 
This  very  important  fact  has  been  demonstrated  by  Prof.  Krahmer,1  who  gives 
the  following  as  the  result  of  his  observations  upon  the  amounts  excreted  in  24 
hours,  after  the  administration  of  diuretics  to  persons  in  health : — 


Medicine  given. 

None 

Juniper 

Venice  Turpentine 

Squill     . 

Digitalis 

Guaiacum 

Colchicum 


Solids 


2.40  oz. 

2.12 

1.94 

2.25 

2.45 

2.43 

2.32 


Organic 
Compounds. 

1.28  OZ. 

0.94 
1.11 

1.04 
1.28 
1.38 
1.36 


Inorganic 
Compounds. 

1.13  oz. 

1.18 

0.83 

1.21 

1.17 

1.05 

0.96 


Similar  results  have  been  obtained  by  Dr.  Golding  Bird,2  who  has  shown  that, 
on  the  other  hand,  there  is  a  class  of  remedies,  which  is  capable  of  producing 
the  most  marked  increase  in  the  amount  of  organic  as  well  as  of  saline  matters 
eliminated  by  the  Kidneys.  These  are  the  Alkalies  and  their  carbonates,  with 
such  of  their  salts  as  are  formed  by  acids  which  are  decomposed  in  the  blood  into 
the  carbonic,  such  as  the  acetates,  tartrates,  and  citrates.  It  has  been  shown 
(CHAP.  ii.  SECT.  1)  that  the  alkalies  and  their  carbonates  have  a  powerful  sol- 
vent action  on  the  albuminous  compounds  generally  ;  and  that  they  tend  to  break 
up  these  compounds  into  simpler  forms  of  combination.  Hence  it  seems  likely 
that  their  presence  in  the  Blood  in  increased  amount  will  tend  to  hasten  the 
retrograde  metamorphosis  of  the  tissues  ;  their  chemical  force  being  exerted,  not 
merely  upon  those  which  are  already  in  a  state  of  disintegration,  but  also  upon 
those,  which,  being  disposed  to  degenerate,  cannot  exercise  that  resisting  power 
which  they  possess  when  in  a  state  of  complete  vital  activity  (§  116).  The 
increase  which  their  administration  occasions  in  the  solids  of  the  Urine  is  strik- 
ingly displayed  in  the  following  comparative  table,  given  by  Dr.  G-.  Bird,  of  the 
entire  constituents  of  the  secretion  passed  during  24  hours,  before  and  after  the 
administration  of  three  drachms  of  acetate  of  potash  :  — 


Quantity  of  Urine 
Specific  Gravity 
Total  Solids 

Uric  Acid      . 
Urea     .... 
Other  Organic  Compounds 
Soluble  Salts         .        i-J> 
Insoluble  Salts      . 


Before  Medicine, 
flgxvi 
1.025 
416  grs. 


2.6  grs. 

130.5    " 

189.3    " 

72.0   " 

21.6    " 


After  Medicine, 
fl^xlvi 
1.017 
782  grs. 

3.5 

202.4 

295.5 

248.4 

32.2 


The  increase  (176.4  grains)  in  the  quantity  of  "  soluble  salts"  is  to  be  chiefly 
set  down  to  the  account  of  the  medicine  taken  in;  but  the  whole  remainder  of 
the  augmentation  seems  fairly  attributable  to  the  increased  metamorphosis.  A 
certain  degree  of  such  increase  is  producible  by  the  simple  ingestion  of  a  large 
amount  of  water  ;  so  that  this  is  by  no  means  so  inoperative  as  it  might  at  first 
sight  appear,  in  cleansing  and  purifying  (so  to  speak)  the  penetralia  of  the 
system.  —  It  seems  highly  probable  that  the  "  critical  evacuations"  of  urine,  as 
of  sweat,  or  fecal  matter,  on  which  the  older  physicians  were  accustomed  to  lay 
great  stress,  are  really  charged  with  noxious  substances,  of  which  the  blood  is 
thus  depurated  ;  and  that  great  benefit  would  frequently  arise  in  practice  from 

1  "Heller's  Archiv.,"  Dec.,  1847. 

2  See  his  "Lectures  on  the  Influence  of  Researches  in  Organic  Chemistry  on  Thera- 
peutics," in  "Medical  Gazette,"  1848,  vol.  xlii.  p.  230. 


OF  THE  SKIN; — CUTANEOUS  TRANSPIRATION. 


611 


Fig.  168. 


the  use  of  the  "alterative  diuretics/'  as  suggested  by  Dr.  G.  Bird,,  where  (as 
in  chronic  rheumatism,  gout,  &c.)  there  is  reason  to  believe  that  a  quantity  of 
mal-assimilated  matter  exists  in  the  system,  of  which  it  is  important  to  get  rid. 
In  many  such  cases,  indeed,  clinical  observation  had  already  established  the 
benefit  derivable  from  such  medicines,  without  affording  the  rationale  of  it. 

4. —  Of  ike  Skin; — Cutaneous  Transpiration. 

646.  The  Skin  is  the  seat  of  various  secretions,  for  each  of  which  it  is  pro- 
vided with  special  organs  (§§  237,  238) ;  but  these  have  reference  chiefly  to  its 
own  protection,  or  to  some  other  local  purpose; 
and  the  only  one  which  can  be  regarded  as 
truly  excrementitious,  is  the  Transpiration  of 
aqueous  fluid,  holding  certain  matters  in  solu- 
tion. The  elimination  of  this  fluid  from  the 
blood  is  effected  by  the  Sudoriparous  glandulae 
(Fig.  168),  which  are  seated  rather  beneath 
than  in  the  Cutis,  and  are  diffused  in  varying 
proportions  over  the  entire  surface  of  the  body 
(§  238).  According  to  Mr.  Erasmus  Wilson,1 
as  many  as  3528  of  these  glandular  exist  in  a 
square  inch  of  surface  on  the  palm  of  the 
hand;  and  as  every  tube,  when  straightened 
out,  is  about  a  quarter  of  an  inch  in  length,  it 
follows  that,  in  a  square  inch  of  skin  from  the 
palm  of  the  hand,  there  exists  a  length  of  tube 
equal  to  882  inches,  or  73  %  feet.  The  number 
of  glandulae  in  other  parts  of  the  skin  is  some- 
times greater,  but  generally  less  than  this;  and 
according  to  Mr.  Wilson,  about  2800  may  be 
taken  as  the  average  number  of  pores  in  each 
square  inch  throughout  the  body.  Now  the 
number  of  square  inches  of  surface,  in  a  man  of 
ordinary  stature,  is  about  2500  ;  the  total  num- 
ber of  pores,  therefore,  may  be  about  seven  mil- 
lions ;  and  the  length  of  the  perspiratory  tubing 
would  thus  be  1,750,000  inches,  or  145,833 
feet,  or  48,611  yards,  or  nearly  28  miles. — 
Although  a  separation  of  fluid  by  this  extensive 
glandular  apparatus  is  continually  taking  place, 
yet  this  fluid,  being  usually  carried  off  in  the 
form  of  vapor  as  fast  as  it  is  separated,  does 
not  accumulate  so  as  to  become  sensible.  If, 
however,  from  the  increased  amount  of  the  se- 
cretion, or  from  the  condition  of  the  surround- 
ing air,  the  whole  fluid  thus  poured  out  should 
not  evaporate,  it  accumulates  in  minute  drops 
upon  the  surface  of  the  skin.  Thus  the  Sudori- 
parous excretion  may  take  the  form  either  of 
sensible  or  of  insensible  transpiration;  the  latter 
being  constant,  the  former  occasional.  It  is 
difficult  to  obtain  enough  of  this  secretion  for 
analysis,  free  from  the  sebaceous  and  other 
matters  which  accumulate  on  the  surface  of  the 
skin ;  and  its  character  can  only,  therefore,  be 


Sudoriparous  Gland  from  the  palm  of  the 
hand,  magnified  40  diam. :  1, 1,  contorted 
tubes,  composing  the  gland,  and  uniting 
into  two  excretory  ducts,  2, 2,  which  unite 
into  one  spiral  canal  that  perforates  the 
epidermis  at  3,  and  opens  on  its  surface  at 
4;  the  gland  is  imbedded  in  fat-vesicles, 
which  are  seen  at  5,  5. 


"On  the  Management  of  the  Skin,"  3d  edit.  p.  37. 


612  OF   SECRETION    AND    EXCRETION. 

stated  approximately.  It  has  usually  an  acid  reaction,  which  seems  due 
to  the  presence  of  acetic  acid;  and  to  this,  or  to  lactic  acid,  we  are  pro- 
bably to  attribute  the  sour  smell  which  it  has,  especially  in  some  disordered 
states  of  the  system.  The  proportion  of  solid  matter,  according  to  Ansel- 
mino,  varies  between  5  and  12.5  parts  in  1000.  The  greater  part  of  it  con- 
sists of  organic  matter,  the  larger  proportion  of  which  appears  to  be  a  protein- 
compound  in  a  state  of  incipient  decomposition ;  urea,  however,  has  been  de- 
tected in  this  product  by  Dr.  Landerer.1  The  remainder  consists  of  saline  com- 
pounds ;  of  which  the  chlorides  of  potassium  and  sodium  appear  to  be  pretty 
constantly  present ;  whilst  muriate  of  ammonia,  alkaline  phosphates,  free  acetic 
and  butyric  acids,  and  acetate  of  soda,  have  also  been  said  to  occur  in  it. — 
The  proportion  of  solid  ingredients  would  probably  be  found  larger  in  the  true 
secretion  of  the  Sudoriparous  glands,  if  we  had  the  means  of  collecting  it  sepa- 
rately ;  for  of  the  whole  fluid  which  passes  off  from  the  surface  of  the  skin,  only 
a  portion  can  be  properly  said  to  be  secreted  by  these  glands,  a  large  part,  as  in 
the  case  of  the  Kidneys,  being  the  product  of  simple  transudation  (§  636).  It 
will  be  this  part  which  will  undergo  augmentation,  when  a  special  determina- 
tion of  blood  to  the  skin  is  produced  by  external  heat ;  and  there  is  no  more 
reason  to  think  that  an  increase  in  the  amount  of  solid  matter  thus  excreted  is 
induced  by  such  agency,  than  that  an  increase  in  the  solids  of  the  urine  can  be 
determined  by  ordinary  diuretics  (§  645).  Hence  the  debilitating  effects  com- 
monly assigned  to  profuse  perspirations  must  be  attributed  to  some  other  causes; 
and  these  it  does  not  seem  very  difficult  to  find.  Thus,  the  great  fatigue  which 
is  experienced  as  a  consequence  of  muscular  exertion  in  a  heated  atmosphere, 
may  fairly  be  set  down  to  the  diminished  activity  of  the  respiratory  process  at 
high  temperatures  (§  564,  a) ;  and  the  "  colliquative  sweating"  of  hectic  fever 
is  obviously  not  a  cause,  but  a  consequence,  of  the  debilitated  state  of  the  gene- 
ral system. 

647.  The  entire  amount  of  fluid  which  is  "  insensibly"  lost  from  the  Cuta- 
neous and  Pulmonary  surfaces  is  estimated  by  Seguin  at  18  grains  per  minute ; 
of  which  11  grains  pass  off  by  the  skin,  and  7  by  the  lungs.  The  maximum 
loss  by  Exhalation,  cutaneous  and  pulmonary,  during  twenty-four  hours  (except 
under  very  peculiar  circumstances)  is  5  Ibs. ;  the  minimum  If  Ib.  It  varies 
greatly,  according  to  the  condition  of  the  atmosphere,  and  that  of  the  body 
itself;  and  these  variations,  as  we  shall  hereafter  see  (§  665),  have  a  most 
important  share  in  the  regulation  of  the  temperature  of  the  body.  The  whole 
amount  of  Cutaneous  transpiration,  "  sensible"  and  "  insensible,"  is  greatly  in- 
creased by  heat  and  dryness  of  the  surrounding  air ;  for  the  heat  occasions  the 
determination  of  an  augmented  amount  of  blood  to  the  cutaneous  vessels ;  and 
of  the  fluid  which  thus  transudes,  a  large  portion  is  carried  off  in  the  state  of 
vapor.  The  more  the  heated  atmosphere  is  already  charged  with  watery  vapor, 
the  smaller  will  be  the  proportion  of  the  transuded  fluid  that  will  thus  "  insen- 
sibly" pass  away;  and  the  more  will  accumulate  as  "sensible"  perspiration. 
Exact  observations  on  this  point,  however,  are  much  wanting,  in  which  not 
merely  the  temperature,  but  the  hygrometrical  state  of  the  air  should  be  prc- 
qisely  determined ;  the  best  hitherto  recorded  being  those  made  by  Dr.  South- 
wood  Smith2  at  the  Phoenix  Gas-Works,  in  which  the  former  element  only  was 
carefully  noted.  These  observations  were  made  upon  eight  of  the  workmen 
employed  in  drawing  and  charging  the  retorts  and  in  making  up  the  fires,  during 
which  they  are  exposed  to  intense  heat ;  the  men  were  accurately  weighed  in 
their  clothes,  immediately  before  they  began,  and  after  they  had  finished  their 
work;  and  in  the  interval  between  the  first  and  second  weighings,  they  were 

1  «  Heller's  Archiv.,"  band  iv.  p.  196. 

*  "Philosophy  of  Health,"  vol.  ii.  pp.  391-396. 


PERSPIRATORY   GLANDULE.  613 

not  allowed  to  partake  of  any  solid  or  liquid  ingesta,  nor  to  part  with  urine  or 
feces. 

Experiment  I.  Nov.  18,  1836.  Day  bright  and  clear.  Temperature  of 
the  air  in  which  the  men  worked,  60°  Fahr.  Barometer  29.25  in.  to  29.4  in. 
Duration  of  labor,  45  minutes. — Average  loss  of  weight,  3  Ibs.  6  oz.;  maximum, 
4  Ibs.  3  oz. ;  minimum  2  Ibs.  8  oz. 

Experiment  II.  Nov.  25,  1836.  Day  foggy,  with  scarcely  any  wind.  Tem- 
perature of  the  air,  39°  Fahr.  Barometer  29.8.  Duration  of  labor,  75  minutes. 
— Average  loss  of  weight,  2  Ibs.  2  oz. ;  maximum,  2  Ibs.  15  oz. ;  minimum, 
14  oz. 

Experiment  III.  June  3,  1837.  Day  exceedingly  bright  and  clear,  with 
little  wind.  Temperature  of  the  air,  60°.  Duration  of  labor,  60  minutes. — 
Average  loss  of  weight,  2  Ibs.  8  oz. ;  maximum,  3  Ibs. ;  minimum,  2  Ibs. 

Experiment  IV.  On  the  same  day,  two  other  men  worked  in  an  unusually 
hot  place  for  70  minutes;  the  loss  of  weight  of  one  of  these  was  4  Ibs.  14  oz. ; 
and  of  the  other,  5  Ibs.  2  oz. 

Although  the  individuals  subjected  to  these  experiments  were  not  in  all 
instances  the  same,  yet  there  was  enough  of  identity  among  them  to  admit  of 
the  certain  inference,  that  the  amount  of  fluid  lost  must  be  influenced  by  the 
state  of  the  individual  system,  as  well  as  by  that  of  the  surrounding  medium. 
Thus  in  the  second  experiment,  Michael  Griffiths  lost  2  Ibs.  6  oz.,  and  Charles 
Cahell  2  Ibs.  15  oz. ;  whilst  in  the  third,  Michael  Griffiths  lost  3  Ibs.,  and 
Charles  Cahell  only  2  Ibs.  It  is  probable  that  the  amount  of  liquid  ingested 
not  long  previously  might  have  a  considerable  influence  on  the  quantity  lost  by 
transpiration  under  such  circumstances. 

648.  The  Cutaneous  excretion,  as  already  pointed  out,  is  in  great  degree 
vicarious  with  the  Urinary,  in  regard  to  the  amount  of  fluid  eliminated;  the 
urine  being  more  watery  in  proportion  as  the  cutaneous  exhalation  is  diminished 
in  amount,  and  vice  versa  (§  636).  But  we  are  also  to.  look  at  these  two  excre- 
tions as  vicarious,  in  regard  to  the  elimination  of  the  products  of  the  "  waste" 
of  the  system.  The  share  which  the  Skin  has  in  this  office  has  probably  been 
generally  underrated.  There  is  reason  to  believe  that  at  least  100  grains  of 
azotized  matter  are  excreted  from  it  daily ;  and  any  cause  which  checks  this 
excretion  must  throw  additional  labor  on  the  kidneys,  and  will  be  likely  to 
produce  disorder  of  their  function. — The  secreting  action  of  the  Skin  is  influ- 
enced by  general  conditions  of  the  vascular  and  nervous  systems;  which  are  as 
yet  ill  understood.  It  is  quite  certain,  however,  that  through  the  influence  of 
the  latter  the  secretion  may  be  excited  or  suspended;  this  is  seen  on  the  one 
hand  in  the  state  of  syncope,  and  in  the  effects  of  depressing  emotions,  espe- 
cially fear,  and  its  more  aggravated  condition,  terror;  and  on  the  other,  in  the 
dry  condition  of  the  skin  during  states  of  high  nervous  excitement.  It  is  very 
probable  that,  in  many  forms  of  fever,  the  suppression  of  the  perspiration  is  a 
cause,  rather  than  an  effect,  of  disordered  vascular  action;  for  there  are  several 
morbid  conditions  of  large  parts  of  the  surface,  in  which  the  suppression  of  the 
transpiration  appears  to  be  one  of  the  chief  sources  of  danger,  having  a  tendency 
to  produce  congestion  and  inflammation  of  internal  organs.  From  the  experi- 
ments of  Dr.  Fourcault,  it  appears  that  complete  suppression  of  the  perspiration 
in  animals,  by  means  of  a  varnish  applied  over  the  skin,  gives  rise  to  a  state 
termed  by  him  "cutaneous  asphyxia;'7  which  is  marked  by  imperfect  arteriali- 
zation  of  the  blood,  and  considerable  fall  of  temperature  (§  660) ;  and  which, 
as  it  produces  death  in  the  lower  animals,  would  probably  do  the  same  in  Man. 
A  partial  suppression  by  the  same  means  gives  rise  to  febrile  symptoms,  and  to 
albuminuria. — There  can  be  no  doubt  whatever  that  imperfect  action  of  the 
Cutaneous  glandulae,  consequent  upon  inactive  habits  of  life  and  want  of  ablu- 
tion, is  a  very  frequent  source  of  disorder  of  the  general  system;  occasioning 


614  EVOLUTION   OF   HEAT,   LIGHT,   AND   ELECTRICITY. 

the  accumulation  of  that  decomposing  organic  matter  in  the  blood  which  it  is 
the  special  office  of  these  glandulse  to  eliminate.  Hence  the  due  maintenance 
of  health  requires  that  this  excretion  should  be  promoted  by  the  use  of  the 
natural  and  appropriate  means  just  referred  to;  and  this  is  the  more  necessary, 
when  from  any  cause  the  function  of  the  kidneys  is  imperfectly  performed. 
There  are  many  diseased  states,  moreover,  in  which  there  appears  to  be  a  special 
determination  of  the  materies  morbi  to  the  skin ;  and  in  which,  therefore,  the 
use  of  means  that  promote  the  cutaneous  excretion  constitutes  the  most  efficient 
method  of  eliminating  them  from  the  blood.1 


CHAPTEE  XIII. 

EVOLUTION    OP   HEAT,    LIGHT,    AND   ELECTRICITY. 

1 .  —  General  Considerations. 

649.  THE  series  of  Nutritive  operations  which  has  now  been  passed  in  review 
has  been  shown  to  consist  in  the  continual  appropriation,  by  the  Animal  organ- 
ism, of  certain  "  organic  compounds"  or  "  alimentary  materials,"  which  have 
been  generated  for  its  use  by  Plants ;  and  in  the  constant  restoration  of  their 
elements  to  the  Inorganic  world,  either  in  the  very  same  forms  of  combination 
in  which  they  originally  existed  there,  or  as  products  of  incipient  decay,  by 
whose  further  decomposition  those  simple  binary  compounds  will  be  reproduced. 
And  thus,  so  far  as  the  material  components  of  the  Organic  Creation  are  con- 
cerned, the  agency  of  Vegetable  life  is  concerned  in  withdrawing  them  from  the 
Mineral  world,  and  that  of  Animal  life  in  returning  them  to  it,  after  they  have 
served  their  purpose  in  the  living  structure.  But  if  we  examine  into  the  source 
of  those  active  powers  or  "  forces,"  on  whose  operation  every  change,  no  less  in 
the  organized  body  than  in  what  is  commonly  designated  as  "inert"  matter,  is 
dependent,  we  shall  find  that  they  are  all  traceable  to  the  solar  radiations.  It 
is  by  the  action  of  the  Light  and  Heat  of  the  Sun  upon  the  Vegetable  germ, 
that  it  is  enabled  to  exercise  its  wonderful  transforming  capacity,  whereby  it 
extracts  carbon,  hydrogen,  nitrogen,  and  oxygen  from  the  carbonic  acid,  water, 
and  ammonia  furnished  by  the  atmosphere  or  the  soil ;  and  that  it  converts  these 
into  the  albuminous,  saccharine,  and  oleaginous  compounds,  which  are  the  des- 
tined food  of  Animals.  And  it  is  under  the  influence  of  Heat  chiefly  derived 
from  the  same  source,  that  the  greater  number  of  tribes  of  Animals  are  enabled 
to  apply  these  compounds  to  the  purposes  of  organization;  and  that,  through 
the  peculiar  instruments  thus  constructed,  those  various  kinds  of  Vital  force  are 
evolved,  whose  operations  are  so  different  from  any  which  we  witness  in  the 
Inorganic  world.  Accordingly,  we  observe  that  the  "rate  of  life"  in  this  larger 
proportion  of  the  Animal  kingdom  is  regulated,  as  in  Plants,  by  the  amount  of 
Heat  supplied  to  the  organism  from  external  sources ;  and  that,  when  the  ex- 

1  The  practical  value  of  active  diaphoresis  in  many  febrile  diseases  is  well  understood 
by  the  native  practitioners  among  the  Negroes  of  the  Guinea  Coast;  who,  according  to  Dr. 
Daniell  (Medical  Topography,  and  Native  Diseases  of  the  Gulf  of  Guinea,  pp.  119-20) 
make  use  of  it  most  successfully  in  the  treatment  of  adynamic  remittent  fevers.  Dr. 
Daniell  states  that  having  himself  had  abundant  experience  of  its  efficacy,  he  has  no  doubt 
of  its  superiority  in  these  cases  to  the  ordinary  practice  of  venesection,  saline  purgatives, 
large  doses  of  calomel,  &c.  And  he  has  repeatedly  stated  that  one  great  secret  of  pre- 
serving health  in  tropical  climates  lies  in  due  attention  to  the  cutaneous  functions. 


EVOLUTION   OP   HEAT.  615 

ternal  temperature  is  reduced  below  a  certain  point,  there  is  an  entire  cessation 
of  all  vital  activity.1  But  there  are  certain  tribes,  especially  Birds  and  Mam- 
mals, which  possess  the  power  of  generating  Heat  within  themselves,  to  such  a 
degree  as  to  render  the  rate  of  their  vital  processes  almost  entirely  independent 
of  external  influences  j  and  there  is  probably  no  one  species  that  can  exercise 
this  power  more  effectually,  and  through  a  greater  range  of  external  conditions, 
than  Man  is  able  to  do.  Of  this  we  shall  presently  have  evidence.  The  evolu- 
tion of  Light,  again,  is  by  no  means  an  unusual  phenomenon  among  the  lower 
tribes  of  Animals ;  but  where  it  does  occur,  it  usually  appears  to  have  some 
special  purpose,  as  is  obvious  enough  in  the  case  of  the  glowworm  and  other 
luminous  Insects.  But  the  luminosity  which  is  occasionally  exhibited  in  Man 
must  be  regarded  as  an  altogether  abnormal  phenomenon,  whose  physiological 
interest  arises  out  of  the  peculiarity  of  the  circumstances  under  which  it  presents 
itself.  Of  the  degree  in  which  Electricity  is  generated  in  the  living  body,  we 
know  comparatively  little.  There  is  strong  evidence  that  a  disturbance  of  Elec- 
tric polarity  must  take  place  in  every  action  of  Organic  as  well  as  of  Inorganic 
Chemistry ;  and  thus  that  every  molecular  change  in  the  Animal  as  well  as  in 
the  Vegetable  organism  must  involve  an  alteration  in  its  electric  condition.  But 
it  would  seem  that  in  the  Animal  body  generally,  these  alterations  are  made  to 
balance  each  other  so  exactly,  that  no  considerable  disturbance  of  the  electric 
equilibrium  ordinarily  takes  place  in  the  organism  as  a  whole ;  and  it  is  only  in 
certain  peculiar  cases  (as  in  the  Electric  Fishes)  that  a  provision  exists  for  the 
generation  of  Electricity  in  considerable  amount  and  intensity,  with  a  view  to 
some  special  purpose.  In  the  Human  subject,  however,  an  extraordinary  pro- 
duction of  free  Electricity,  as  of  Light,  occasionally  presents  itself;  and  this, 
taken  in  connection  with  other  evidence,  would  seem  rather  to  indicate  a  depart- 
ure from  the  usual  balance  between  the  opposite  electrical  changes  continually 
taking  place,  than  to  be  due  to  the  introduction  of  any  extraordinary  sources  of 
electric  disturbance.2 

2. — Evolution  of  Heat. 

650.  All  the  vital  actions  of  the  body  of  Man,  as  of  that  of  "warm-blooded" 
animals  generally,  require  an  elevated  temperature  as  a  condition  of  their  per- 
formance ;  and  the  high  degree  of  constancy  and  regularity  which  is  observable 
in  these  actions  appears  to  depend  in  great  degree  upon  the  provision  which 
the  organism  contains  within  itself  for  the  maintenance  of  that  temperature  at 
a  fixed  standard.  This  constancy  and  regularity  are  most  remarkably  exhibited 
in  the  various  periodical  changes  to  which  the  body  is  subject  both  in  health 
and  disease;  the  uniformity  of  whose  recurrence  is  due  to  a  corresponding  uni- 
formity in  the  rate  of  vital  action  taking  place  in  the  interval.  Thus,  as  will 
be  shown  hereafter,  the  period  of  parturition  is  in  great  degree  determined  by 
the  maturation  of  the  foetal  structures ;  and  the  uniformity  of  the  time  which 
this  requires  (like  the  corresponding  uniformity  in  the  period  of  development  in 
the  embryo  bird)  may  be  fairly  attributed  to  the  regularity  of  the  supply  of 
Heat,  which  is  the  power  that  especially  determines  the  formative  operations. 
For  the  periods  of  all  similar  phenomena  in  "  cold-blooded"  animals,  which  have 
no  power  of  maintaining  an  independent  temperature,  exhibit  no  such  uniformity; 

1  See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  CHAP.  in.  Sect.  3,  Am.  Ed. 

2  Having  recently  had  an  opportunity  of  witnessing  some  of  the  experiments  made  by 
M.  Du  Bois  Reymond  with  a  magneto-electrometer  of  extraordinary  sensitiveness,  the  Au- 
thor can  bear  his  personal  testimony  to  the  fact,  that  the  electricity  even  of  the  corre- 
sponding fingers  of  the  two  hands  is  very  seldom  equally  balanced,  and  that  the  existence 
of  even  the  slightest  scratch  or  abrasion  of  surface  upon  one  of  them  produces  a  very 
marked  disturbance. 


616 


EVOLUTION   OF   HEAT,    LIGHT,    AND   ELECTRICITY. 


being  entirely  dependent  (as  in  Plants)  upon  the  degree  of  external  warmth  to 
which  their  bodies  are  subjected.  We  shall  now  inquire,  in  the  first  place,  into 
the  amount  of  Heat  thus  generated  by  Man ;  and  then  into  the  sources  of  its 
production. 

651.  Our  present  knowledge  of  the  ordinary  Temperature  of  the  Human 
body  under  different  circumstances  is  chiefly  due  to  the  investigations  of  Dr. 
J.  Davy.1 — The  first  series  of  his  observations  included  114  individuals  of  both 
sexes,  of  different  ages,  and  among  various  races,  in  different  latitudes,  and  under 
various  temperatures;  the  external  temperature,  however,  was  in  no  instance 
very  low,  and  the  variations  were  by  no  means  extreme.  The  mean  of  the  ages 
of  all  the  individuals  was  27  years.  The  following  is  a  general  statement  of 
the  results,  the  temperature  of  the  body  having  been  ascertained-  by  a  thermo- 
meter placed  under  the  tongue : — 


Temperature  of  the  air  60° 
69° 
78° 
79.5° 
80° 
82° 

Mean  of  all  the  experiments  74° 
Highest  temperature  of  air  82° 
Lowest  temperature  of  air  60° 


Average  temperature  of  the  body 


Mean  of  all  the  experiments 
Highest  temperature  of  body 
Lowest  temperature  of  body 


98.28° 

98.15° 

98.85° 

99.21° 

99.67° 

99.9° 

100° 

102° 

96.5° 


From  this  we  see  that  the  variations  noted  by  Dr.  Davy,  which  were  evidently 
in  part  the  consequence  of  variations  in  external  temperature,  but  which  were 
also  partly  attributable  to  individual  peculiarities,  amounted  to  5£  degrees;  the 
lower  extreme  might  be  found  to  undergo  still  further  depression,  if  the  inquiries 
were  carried  on  in  very  cold  climates. — Dr.  Davy's  subsequent  inquiries  have 
been  directed  to  the  determination  of  the  various  influences  which  tend  to  pro- 
duce a  departure  from  the  average;  and  it  will  be  advantageous  to  present  his 
results  in  a  systematized  form,  in  combination  with  those  of  other  observers. 
The  most  important  of  these  variations  seem  to  be  those  dependent  upon  Age, 
Period  of  the  Day,  Exercise  or  Repose,  Ingestion  of  Food  or  Drink,  and  Ex- 
ternal Temperature. 

a.  The  temperature  of  Infants,  according  to  the  observations  of  Dr.  Davy, 
M.  Roger,3  and  of  Dr.  Gr.  C.  Holland,3  is  somewhat  higher  than  that  of  adults,4 
provided  that  they  are  placed  in  conditions  favorable  to  its  sustenance ;  but,  as 
will  be  shown  hereafter,  infants  and  young  children  are  very  inferior  to  adults 
in  their  power  of  resisting  the  depressing  influenced  external  cold  (§  664). 
Their  temperature,  when  examined  immediately  after  birth  by  a  thermometer 
in  the  axilla,  is  nearly  100°;  but  it  quickly  falls  to  about  95.5°,  and  gradually 
rises  in  the  course  of  the  next  twenty-four  hours  to  about  97.7°  in  weakly  sub- 
jects, and  to  99.5°  in  strong  infants.  Between  four  months  and  six  years  of 
age,  M.  Roger  found  the  average  temperature  to  be  98.9° ;  and  between  six  and 
fourteen  years  of  age,  99.16°. — The  temperature  of  aged  persons,  from  the  ob- 
servations of  Dr.  J.  Davy,  does  not  seem  to  be  below  that  of  persons  in  the 
vigor  of  life,  provided  that  there  be  no  external  depressing  influences :  but  they 

1  See  his  successive  Memoirs  in  the  "Philosophical  Transactions"  for  1814  (republished 
in  Dr.  D.'s  "Anatomical  and  Physiological  Researches"),  1844,  1845,  and  1850. 

2  "  Archiv.  G6n.  de  Me"d.,"  1844. 

8  "Inquiry  into  the  Laws  of  Life,"  1829. 

4  Dr.  W.  F.  Edwards  ("On  the  Influence  of  Physical  Agents  on  Life,"  p.  115)  gives  as 
the  result  of  his  observations,  which  were  only  ten  in  number,  that  the  temperature  of 
infants  is  lower  than  that  stated  above ;  but  it  is  obvious  that  these  observations  were 
made  during  the  period  of  depression  which  occurs  in  the  first  days,  whilst  the  respiratory 
function  is  becoming  established. 


EVOLUTION   OF   HEAT. 


617 


seem,  like  infants  and  young  children,  to  have  less  power  of  resisting  external 
cold,  the  temperature  of  their  bodies  being  more  easily  and  considerably  re- 
duced by  it  than  is  that  of  adults;  and  hence  probably  it  has  happened,  that 
popular  opinion  assigns  to  them  an  habitually  inferior  temperature. 

b.  A  slight  diurnal  variation  in  the  temperature  of  the  body  appears  usually 
to  take  place,  quite  irrespectively  of  external  heat  or  cold;  but  this  does  not 
seem  to  be  very  constant  either  in  its  period  or  its  degree,  and  is  seldom  very 
considerable.  Thus  Dr.  Davy  found,  from  a  long  series  of  observations  carried 
on  upon  himself  whilst  in  England,  that  the  body  was  warmest  in  the  morning, 
and  coldest  at  night ;  whilst  the  reverse  was  the  case  in  Barbadoes.  The  follow- 
ing table  gives  his  average  results  : — 


Mean  temperature  under  the  tongue. 

\-_  Temperature  of  Room. 

Engird      {«$£• 

2-4  P.  M. 

9852° 

12P.M. 

97.92° 

7-8  A.  M. 
50.9° 

2-4  p.  M. 
54.7° 

12P.M. 

62° 

-r,        ,        ,                  f  6-7  A.  M. 

Barbadoes    j    gg  ^0 

12-2  P.  M. 
98.9° 

9-11  P.M. 

99° 

6-7  A.  M. 

76.7° 

12-2  p.  M. 
83.6° 

9-11  P.M. 

79° 

From  the  observations  of  M.  Chossat  on  Birds,  in  which  <fche  diurnal  variation 
amounts  to  li  Fahr.,  it  seems  that  the  maximum  is  pretfy  constantly  at  noon, 
and  the  minimum  near  midnight;  and  this  corresponds  well  with  what  has 
already  been  pointed  out,  with  regard  to  the  relative  activity  of  respiration  at 
different  periods  of  the  twenty-four  hours  (§  564,  i).  Probably  there  is  a  less 
capacity  for  generating  heat  during  the  night ;  so  that,  if  the  body  be  insuffi- 
ciently protected  by  clothing,  or  be  exposed  to  a  low  degree  of  external  tempera- 
ture, its  own  temperature  will  be  more  readily  lowered :  and  thus  the  minimum 
of  the  whole  day  may  come  to  present  itself  at  this  part  of  it,  in  a  temperate 
climate;  whilst  in  a  tropical  climate,  the  light  bed-covering  and  free  circulation 
of  air  usual  in  the  sleeping-room,  together  with  the  depressing  influence  of  re- 
pose, would  tend  to  render  the  early  morning  temperature  the  lowest. 

c.  That  an  increase  in  the  heat  of  the  body  is  produced  by  exercise,  and  that 
repose  tends  to  its  reduction,  is  a  matter  of  familiar  experience;  but  the  observa- 
tions of  Dr.  Davy  show  that  there  is  scarcely  any  perceptible  difference  in  the 
heat  of  the  deep-seated  parts,  the  augmentation  and  depression  being  confined 
to  the  extremities.     Thus,  on  one  occasion  recorded  by  him,  the  temperature  of 
the  air  of  the  room  before  walking  being  60°,  that  of  the  feet  (the  thermometer 
being  placed  between  the  toes)  being  only  66°,  that  of  the  thermometer  under 
the  tongue  being  98°,  and  that  of  the  urine  100° — the  temperature  after  a  walk 
in  the  open  air  at  40°,  the  exercise  having  diffused  a  feeling  of  gentle  warmth 
through  the  body,  was  96.5°  in  the  feet,  97°  in  the  hands,  98°  under  the  tongue, 
and  101°  in  the  urine.     So  on  another  occasion,  the  temperature  having  been 
66°  in  the  room,  75°  in  the  feet,  81°  in  the  hands,  98°  under  the  tongue,  and 
100°  in  the  urine — after  a  walk  in  air  at  50°,  the  temperature  was  99°  in  the 
feet,  98°  in  the  hands,  98°  under  the  tongue,  and  101.5°  in  the  urine. 

d.  The  influence  of  ingestion  of  food  upon  the  temperature  of  the  body  has 
not  yet  been  duly  investigated.     Common  experience  leads  to  the  conclusion, 
that  after  a  meal,  as  after  exercise,  there  is  a  greater  warmth  in  the  extremities ; 
but  Dr.  Davy's  observations  show  that,  in  his   own  case,  whilst  in  England, 
there  was  usually  an  appreciable  depression  immediately  after  dinner,  though 
in  Barbadoes  the  effect  of  a  moderate  meal  was  to  produce  an  elevation.     In 
both  cases,  however,  Dr.  D.  observed  that  the  ingestion  of  wine  has  a  positive- 
ly depressing  influence  on  the  temperature  of  the  body,  which  increases  with 
the  quantity  taken ;   and  it  may  have  been  the  constant  employment  of  wine 


618 

with  his  dinner  which  was  the  real  cause  of  the  depression  observed  in  Eng- 
land.1 

e.  The  influence  of  external  temperature  is  sufficiently  apparent  in  the  ob- 
servations already  cited;  for  although  external  cold  may  act  in  a  different  de- 
gree on  different  individuals,  according  to  their  respective  ages,  powers  of 
resistance,  &c.,  yet  there  is  ample  proof  that  on  the  whole  a  continued  exposure 
to  it  reduces  the  temperature  of  the  body  somewhat  below  its  ordinary  standard, 
whilst  continued  exposure  to  heat  occasions  a  slight  elevation  in  the  temperature 
of  the  body.  The  influence  of  cold  is,  of  course,  most  powerfully  exerted  when 
the  body  is  at  rest;  and  under  such  circumstances  Dr.  Davy  found  the  tempera- 
ture of  his  own  body  to  be  reduced,  on  an  average  of  four  observations,  to 
96.7°,  the  average  temperature  of  the  surrounding  air  having  been  37°.  On 
comparing  the  bodily  temperature  of  different  individuals  working  in  rooms  of 
various  temperatures  in  the  same  factory,  Dr.  Davy  found  the  tongue-thermo- 
meter rise  to  100°  in  one  man,  and  to  100.5°  in  another,  who  had  been  working 
for  some  hours  in  a  room  at  92°;  whilst  it  was  99°  in  a  young  woman  who 
worked  in  a  room  at  73°,  and  only  97.5°  in  another  who  worked  in  a  tempera- 
ture of  60°.  The  effects  of  seasonal  change  are  less  marked  in  Man  than  they 
are  in  the  lower  animals,  which  are  more  exposed  to  extremes  of  temperature ; 
but  it  seems  principally  exerted  in  modifying  the  heat-producing  power.  For 
it  has  been  shown  by  Dr.  W.  F.  Edwards  (Op.  cit.),  that  warm-blooded  animals 
are  more  speedily  killed  by  extreme  cold  in  summer  than  in  winter;  and  it 
seems  probable,  therefore,  that  we  are  partly  to  attribute  the  peculiar  chilling 
influence  of  a  cold  day  in  summer,  and  the  oppressiveness  of  a  warm  day  in 
winter,  to  the  seasonal  change  in  the  body  itself;  although  the  effect  is  doubt- 
less referable  in  part  to  the  effect  of  contrast  upon  our  own  feelings. 

652.  The  usual  Temperature  of  the  body  occasionally  undergoes  consider- 
able alteration  in  disease  ;  and  this  in  the  way  either  of  increase  or  of  diminu- 
tion. Thus  in  maladies  which  involve  an  acceleration  of  pulse  and  a  quickening 
of  the  respiration,  the  temperature  is  generally  higher  than  usual,  even  though 
a  large  portion  of  the  lung  maybe  unfit  for  its  function.  This  is  often  remark- 
ably seen  in  the  last  stages  of  phthisis,  when  the  inspirations  are  extremely 
rapid,  and  the  pulse  so  quick  as  scarcely  to  admit  of  being  counted ;  the  skin,  in 
such  cases,  often  becomes  almost  painfully  hot.  On  the  other  hand,  in  diseases 
of  the  contrary  character,  such  as  "  morbus  cceruleus,"  asthma,  and  cholera,  the 
temperature  of  the  body  falls ;  a  reduction  to  78°  having  been  noticed  in  the 
former  maladies,  and  to  67°  in  the  latter.  The  range  observed  by  M.  Andral 
in  diseases  which  less  affected  the  calorifying  function,  was  from  95°  to  107.6°; 
and  by  M.  Roger  (loc.  cit.),  in  diseases  of  children,  from  74.3  to  108.5.  Prof. 
Dunglison3  speaks  of  having  seen  the  thermometer  at  106°  in  scarlatina  and 
typhus ;  and  Dr.  Francis  Home3  found  it  to  stand  at  104°  in  two  individuals 
in  the  cold  stage  of  an  intermittent,  whilst  it  afterwards  fell  to  101°,  and  subse- 
quently to  99°,  during  the  sweating  stage.  Dr.  Edwards  mentions  a  case  of 
tetanus,  in  which  the  temperature  of  the  body  rose  to  HOf  °.  The  following 

1  This  difference  in  effect  noted  by  Dr.  Davy,  between  a  moderate  quantity  of  wine 
taken  with  dinner  in  England  and  in  Barbadoes,  seems  readily  explicable  by  the  fact  that 
the  presence  of  Alcohol  in  the  blood  diminishes  for  a  time  the  energy  of  the  proper  com- 
bustive  process  (§  264,  A).     For,  when  the  temperature, of  the  atmosphere  is  considerably 
below  that  of  the  body,  this  retardation  of  the  combustive  process  occasioned  by  the  wine 
will  allow  the  heat  of  the  body  to  be  lowered  by  it,  notwithstanding  the  tendency  to  in- 
creased activity  of  the  circulation  and  respiration  which  the  meal  alone  would  exert.     In 
a  warm  climate,  on  the  other  hand,  the  cooling  influence  of  the  external  air  would  not  be 
sufficient  to  produce  this  reduction  in  the  temperature  of  the  body,  notwithstanding  the 
retarding  influence  of  the  wine  upon  the  combustive  process. 

2  "Human  Physiology,"  7th  edit.,  vol.  ii.  p.  225. 

3  "Medical  Facts  and  Experiments,"  London,  1759. 


EVOLUTION   OP    HEAT.  619 

observations  have  been  made  on  this  subject  by  M.  Donne  r1  in  a  case  of  puer- 
peral fever,  the  pulse  being  168,  and  the  respiration  48  per  minute,  the  tempera- 
ture was  104°;  in  a  case  of  hypertrophy  of  the  heart,  the  pulse  being  150  and 
the  respirations  34,  the  temperature  was  103°  ;  in  a  case  of  typhoid  fever,  the 
pulse  being  136,  and  the  respirations  50,  the  temperature,  was  104° ;  and  in  a 
case  of  phthisis,  the  pulse  being  140,  and  the  respirations  62,  the  temperature 
was  102° ;  on  the  other  hand,  in  a  case  of  jaundice,  in  which  the  pulse  was  but 
52,  the  temperature  was  only  96.40° ;  but  the  same  temperature  was  observed 
in  a  case  of  diabetes,  in  which  the  pulse  was  84.  These  limited  observations, 
whilst  they  clearly  indicate  that  a  general  relation  exists  between  the  tempera- 
ture of  the  body  and  the  rapidity  of  the  pulse,  also  show  that  this  relation  is 
by  no  means  invariable,  but  that  it  is  liable  to  be  affected  by  several  causes,  of 
which  our  knowledge  is  as  yet  very  limited. — It  is  not  a  little  remarkable  that 
the  temperature  of  the  body  should  sometimes  rise  considerably  after  death  ; 
and  this  not  merely  in  such  diseases  as  Cholera,  in  which  it  has  undergone  an 
extreme  depression  during  the  latter  part  of  life;  but  even  in  the  case  of  febrile 
disorders,  in  which  the  temperature  during  life  has  been  above  the  usual  stand- 
ard. This  has  been  ascertained  by  Dr.  Bennett  Dowler3  of  New  Orleans,  on 
the  bodies  of  those  yellow-fever  subjects  which  have  already  been  referred  to  as 
exhibiting  a  remarkable  degree  of  molecular  life  after  somatic  death  (§§  328, 
552).  In  one  case,  for  example,  the  highest  temperature  during  life  was  in 
the  axilla,  104° ;  ten  minutes  after  death  it  had  risen  to  109°  in  the  axilla  ; 
fifteen  minutes  afterwards  it  was  113°  in  an  incision  in  the  thigh;  in  twenty 
minutes  the  liver  gave  112° ;  in  one  hour  and  forty  minutes,  the  heart  gave 
109°,  and  the  thigh  in  the  former  incision  109°  ;  and  in  three  hours  after  the 
removal  of  all  the  viscera,  a  new  incision  in  the  thigh  gave  110°.  It  is  curious 
that  the  maximum  of  the  heat  observed  after  death  should  have  been  in  the 
thigh,  and  the  minimum  in  the  brain ;  as  is  shown  in  the  following  table  of  the 
highest  amount  of  temperature  noted  in  eight  different  regions  in  five  subjects : — 

Thigh.  Epigastrium.       Axilla.          Chest.  Heart.          Brain.         Rectum.         Liver. 

113°  111° 

109°  110° 

109°  109° 

109°  109° 

108°  109° 


109° 

107° 

109° 

102° 

111° 

112° 

109° 

106.5° 

106° 

101° 

109° 

109° 

108° 

106° 

105° 

101° 

107° 

108° 

108° 

106° 

104° 

100° 

107° 

107° 

107° 

105° 

104° 

99° 

106° 

106° 

Mean  109.6°         109.6°          108.2°       106.1°       105.6°       100.6°       108°          108.4° 

653.  Although  there  appears  to  be,  for  all  species  of  animals,  a  distinct  limit 
to  the  variations  of  bodily  temperature,  under  which  their  vital  operations  can 
be  carried  on,  this  limitation  does  not  prevent  animals  from  existing  in  the 
midst  of  great  diversities  of  external  conditions ;  since  they  have  within  them- 
selves the  power  of  compensating  for  these,  in  a  very  extraordinary  degree. 
This  power  seems  to  exist  in  Man  to  a  higher  amount  than  in  most  other  ani- 
mals; since  he  cannot  only  support  but  enjoy  life,  under  extremes,  of  which 
either  would  be  fatal  to  many.  In  many  parts  of  the  tropical  zone,  the  ther- 
mometer rises  every  day,  through  a  large  portion  of  the  year,  to  110°;  and  in 
British  India  it  is  said  to  be  seen  occasionally  at  130°.  On  the  other  hand, 
the  degree  of  cold  frequently  sustained  by  Arctic  voyagers,  and  quite  en- 
durable under  proper  precautions,  appears  much  more  astonishing;  by  Captain 
Parry,  the  thermometer  has  been  seen  as  low  as  — 55°,  or  87°  below  the  freez- 
ing point;  by  Captain  Franklin  at  — 58°,  or  90°  below  the  freezing  point;  and 

'  "Archives  Gen.  de  Med.,"  Oct.  1835;  and  "  Brit,  and  For.  Med.  Rev.,"  vol.  ii.  p.  248. 

2  "Western  Journal  of  Medicine  and  Surgery,"  June  and  Oct.,  1844;  cited  in  "Phila- 
delphia Medical  Examiner,"  June,  1845,  and  in  Prof.  Dunglison's  "Human  Physiology," 
7th  edit.,  vol.  ii.  p.  718. 


620  EVOLUTION    OF   HEAT,    LIGHT,    AND   ELECTRICITY. 

by  Captain  Back  at  — 70°,  or  102°  below  the  freezing  point.  In  both  cases, 
the  effect  of  the  atmospheric  temperature  on  the  body  is  greatly  influenced  by 
the  condition  of  the  air  as  to  motion  or  rest;  thus,  every  one  has  heard  of  the 
almost  unbearable  oppressiveness  of  the  "sirocco,"  or  hot  wind  of  Sicily  and 
Italy,  the  actual  temperature  of  which  is  not  higher  than  has  often  been  ex- 
perienced without  any  great  discomfort,  when  the  air  is  calm :  and,  on  the 
other  side,  it  may  be  mentioned  that,  in  the  experience  of  many  Arctic  voyagers, 
a  temperature  of  — 50°  may  be  sustained,  when  the  air  is  perfectly  still,  with 
less  inconvenience  than  is  caused  by  air  in  motion  at  a  temperature  fifty  degrees 
higher.1  This  is  quite  conformable  to  what  might  be  anticipated  on  physical 
principles. 

654.  Again,  the  degree  of  moisture  contained  in  a  heated  atmosphere  makes 
a  great  difference  jn  the  degree  of  elevation  of  temperature,  which  may  be  sus- 
tained without  inconvenience.  Many  instances  are  on  record,  of  a  heat  of  from 
250°  to  280°  being  endured  in  dry  air  for  a  considerable  length  of  time,  even 
by  persons  unaccustomed  to  a  particularly  high  temperature ;  and  persons  whose 
occupations  are  such  as  to  require  it  can  sustain  a  much  higher  degree  of  heat, 
though  not  perhaps  for  any  long  period.  The  workmen  of  the  late  Sir  F. 
Chantrey  were  accustomed  to  enter  a  furnace  in  which  his  moulds  were  dried, 
whilst  the  floor  was  red-hot,  and  a  thermometer  in  the  air  stood  at  350°;  and 
Chabert,  the  "Fire-king,"  was  in  the  habit  of  entering  an  oven  whose  tempera- 
ture was  from  400°  to  600 °.2  It  is  possible  that  these  feats  might  be  easily 
matched  by  many  workmen  who  are  habitually  exposed  to  high  temperatures ; 
such  as  those  employed  in  Iron-foundries,  Grlass-houses,  and  Gas-works.  In  all 
these  instances,  the  dryness  of  the  air  facilitates  the  rapidity  of  the  vaporization 
of  the  fluid,  whose  secretion  by  the  Cutaneous  glandulse  is  promoted  by  heat 
applied  to  the  surface;  and  the  large  amount  of  caloric  which  is  consumed  in 
this  change  is  for  the  most  part  withdrawn  from  the  body,  the  temperature  of 
which  is  thus  kept  down.  Exposure  to  a  very  elevated  temperature,  however, 
if  continued  for  a  sufficient  length  of  time,  does  produce  a  certain  elevation  of 
that  of  the  body;  as  might  be  expected  from  the  statements  already  made,  in 
regard  to  the  variation  in  the  heat  of  the  body  with  changes  in  atmospheric 
temperature  (§  651).  In  the  experiments  of  MM.  Berger  and  Delaroche,3  it 
was  found  that,  after  the  body  had  been  exposed  to  air  of  120°  during  17 
minutes,  a  thermometer  placed  in  the  mouth  rose  nearly  7°  above  the  ordinary 
temperature;  it  may  be  remarked,  however,  that,  as  the  body  was  immersed  in 

1  The  Author  has  been  informed  by  Sir  John  Richardson,  that  in  his  last  Arctic  Expedi- 
tion, whilst  at  winter  quarters,  he  was  accustomed  to  go  from  his  sitting-room,  to  the 
magnetic  observatory  at  a  short  distance  (about  an  ordinary  street's  bi'eadth),  without 
feeling  it  necessary  even  to  put  on  a  great-coat ;  although  the  temperature  of  the  former 
was  about  50°,  and  that  of  the  air  through  which  he  had  to  pass  to  the  latter  was  — 50°, 
the  difference  being  100°.     This  immunity  from  chilling  influence  was  chiefly  attributable 
to  the  dryness  and  stillness  of  the  atmosphere;  but  it  is  worthy  of  note  that  Sir  J.  R.  and 
the  whole  of  his  party  on  this  expedition,  abstained  entirely  from  alcoholic  liquors;   and 
the  Author  has  received  his  personal  assurance,  that  his  experience  on  this  occasion  fully 
bore  out  his  previous  conviction,  that  continued  severe  cold  is  much  better  borne  without 
recourse  to  these  liquors,  than  under  the  employment  of  them. 

2  The  wonderful  feats  performed  by  many  individuals  from  time  to  time — of  dipping  the 
hand  into  melted  lead,  laying  hold  of  a  red-hot  iron,  &c. — have  been  recently  shown  by 
M.  de  Boutigny  to  be  explicable  upon  very  simple  principles.     For  in  all  such  cases,  a 
thin  film  of  aqueous  fluid  in  the  "spherical  state"  intervenes  between  the  skin  and  the 
heated  surface ;  and  a  hand  which  is  naturally  damp,  or  which  has  been  slightly  moistened, 
may  be  safely  passed  into  the  stream  of  molten  iron  as  it  flows  from  the  furnace ;  as  was 
demonstrated  by  M.  de  Boutigny  at  the  recent  meeting  of  the  British  Association  at  Ips- 
wich (1851). 

3  "  Experiences  sur  les  Effets  qu'une  forte  Chaleur  produit  sur  1'Economie;"  Paris, 
1805:  and  "Journal  de  Physique,"  tomes  Ixiii.,  Ixxi.,  et  Ixxvii. 


EVOLUTION   OF   HEAT.  621 

a  close  box,  from  which  the  head  projected  (in  order  to  avoid  the  direct  in- 
fluence of  the  heated  air  on  the  temperature  of  the  mouth),  the  air  had  pro- 
bably become  charged  with  the  vapor  exhaled  from  the  surface,  and  had, 
therefore,  somewhat  of  the  effects  of  a  moist  atmosphere.  At  any  rate,  the 
temperature  of  the  body  does  not  appear  to  rise,  under  any  circumstances,  to  a 
degree  very  much  greater  than  this.  In  one  of  the  experiments  of  Drs.  Fordyce 
and  Blagden,1  the  temperature  of  a  Dog,  that  had  been  shut  up  for  half  an  hour 
in  a  chamber  of  which  the  temperature  was  between  220°  and  236°,  was  found 
to  have  risen  from  101°  to  about  108°.  MM.  Delaroche  and  Berger  tried 
several  experiments  on  different  species  of  animals,  in  order  to  ascertain  the 
highest  temperature  to  which  the  body  could  be  raised  without  the  destruction 
of  life,  by  inclosing  them  in  air  heated  from  122°  to  201°,  until  they  died:  the 
result  was  very  uniform,  the  temperature  of  the  body  at  the  end  of  the  experi- 
ment only  varying  in  the  different  species  between  11°  and  13°  above  their 
natural  standard :  whence  it  may  be  inferred  that  an  elevation  to  this  degree 
must  be  fatal.  This  elevation  would  be  attained  comparatively  soon  in  a  moist 
atmosphere;  partly  because  of  the  greater  conducting  power  of  the  medium; 
but  principally  on  account  of  the  check  which  is  put  upon  the  vaporization  of 
the  fluid  secreted  by  the  skin.  Even  here,  however,  custom  and  acquired  con- 
stitution have  a  very  striking  influence;  for  whilst  the  inhabitants  of  this 
country  are  unable  to  sustain,  during  more  than  10  or  12  minutes,  immersion 
in  a  vapor-bath  of  the  temperature  of  110°  or  120°,  the  Finnish  peasantry  re- 
main for  half  an  hour  or  more  in  a  vapor-bath  the  temperature  of  which  finally 
rises  even  to  158°  or  167°. — Accurate  experiments  are  yet  wanting  to  deter- 
mine the  influence  of  humidity  on  the  effects  of  cold  air.  From  experiments 
on  young  Birds  incapable  of  maintaining  their  own  temperature,  of  which  some 
were  placed  in  cold  dry  air,  and  others  in  cold  air  charged  with  moisture,  it  was 
found  by  Dr.  Edwards  that  the  loss  of  heat  was  in  both  instances  the  same ; 
the  effect  of  the  evaporation  from  the  surface  in  the  former  case  being  counter- 
balanced in  the  latter  by  the  depressing  influence  of  the  cold  moisture.  This 
influence,  the  existence  of  which  is  a  matter  of  ordinary  experience,  is  probably 
exerted  directly  upon  the  nervous  system. 

655.  Having  thus  considered  the  general  facts  which  indicate  the  faculty 
possessed  by  the  living  system,  in  the  higher  Animals,  of  keeping  up  its  temper- 
ature to  an  elevated  standard,  and  of  preventing  it  from  being  raised  much 
beyond  it  by  any  degree  of  external  heat,  we  have  next  to  inquire  to  what  this 
faculty  is  due. — In  forming  an  opinion  upon  this  point,  it  is  of  fundamental 
importance  to  bear  in  mind  that  the  production  of  Heat  is  not  peculiar  to  Ani- 
mals, but  is  exhibited  also  by  Plants,  in  parts  in  which  certain  vital  operations 
that  involve  the  production  of  carbonic  acid,  are  taking  place  with  unusual 
rapidity,  and  under  circumstances  which  tend  to  prevent  the  dissipation  of  the 
heat  thus  generated.  This  is  pre-eminently  the  case  during  the  periods  of  germ- 
ination and  flowering ;  as  may  be  seen  in  the  act  of  malting,  where  a  number 
of  germinating  seeds  being  heaped  together,  the  thermometer  in  the  midst  of 
them  has  been  observed  to  rise  to  110°;  whilst  during  the  flowering  of  the 
Arum  tribe,  whose  blossoms  are  crowded  together  on  spadixes,  and  these  are 
inclosed  in  protective  spathes,  a  thermometer  placed  in  the  midst  of  twelve 
spadixes  has  been  seen  to  rise  to  121°,  the  temperature  of  the  surrounding  air 
being  only  66°. a  In  all  such  cases,  the  elevation  of  temperature  is  found  to  be 
a  very  constant  ratio  to  the  amount  of  carbonic  acid  which  is  produced  by  the 
union  of  atmospheric  oxygen  with  carbon  set  free  from  the  vegetable  tissues;3 

1  "Philosophical  Transactions,"  1775. 

2  See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  $  615,  616,  Am.  Ed. 

3  This  has  been  made  yet  more  certain  by  the  recent  observations  of  M.  Garreau  ("  Ann. 
des  Sci.  Nat.,"  3me  serie,  Botan.,  torn.  xvi.  p.  250),  who  has  noted  the  temperature  of 


622 


EVOLUTION   OF    HEAT,    LIGHT,    AND   ELECTRICITY. 


so  that  it  is  scarcely  possible  to  entertain  a  reasonable  doubt,  that  the  produc- 
tion of  Heat  in  Plants  is  dependent  upon  a  process  of  slow  combustion. — When 
the  general  phenomena  of  Calorification  in  Animals  are  carefully  examined, 
they  are  found  to  harmonize  with  this  view.  Throughout  the  whole  kingdom, 
a  close  and  exact  conformity  may  be  perceived  between  the  amount  of  Oxygen 
consumed  and  of  Carbonic  acid  given  off,  and  the  degree  of  Heat  liberated.  In 
the  cold-blooded  animals,  whose  temperature  is  almost  entirely  dependent  upon 
that  of  the  surrounding  element,  the  respiration  is  feeble ;  being  carried  on,  for 
the  most  part,  through  the  medium  of  water.  In  the  warm-blooded  Vertebrata, 
however,  which  have  the  power  of  keeping  up  the  heat  of  their  bodies  to  an  ele- 
vated standard,  even  when  that  of  the  surrounding  air  is  far  beneath  it,  the 
quantity  of  oxygen  consumed  is  very  large ;  and  that  required  by  Birds  is  more, 
in  proportion  to  their  size,  than  that  employed  by  Mammalia,  as  we  should  ex- 
pect from  the  more  elevated  temperature  of  the  former.  In  the  class  of  Insects, 
we  have  a  very  remarkable  illustration  of  the  same  general  fact.  It  appears, 
from  the  researches  of  Mr.  Newport,1  that  Insects,  during  their  larva  and  pupa 
states,  and  even  in  their  perfect  condition  when  at  rest,  are  to  be  regarded  as 
truly  cold-blooded  animals ;  their  temperature  rising  and  falling  with  that  of 
the  surrounding  medium,  and  being  at  no  time  more  than  a  degree  or  two  above 
it.  In  a  state  of  activity,  however,  the  temperature  of  the  body  attains  a  con- 
siderable elevation ;  frequently  as  much  as  10°  or  15°  above  that  of  the  air.  It 
must  be  remembered  that,  owing  to  their  larger  extent  of  surface  in  proportion 
to  their  bulk,  small  animals  are  cooled  much  more  rapidly  than  large  ones ;  and 
the  temperature  of  insects  would  probably  rise  much  higher,  if  it  were  not 
for  the  loss  they  are  thus  continually  experiencing,  which  is  greatly  increased 
by  the  action  of  the  wings.  In  one  of  Mr.  N/s  experiments,  a  single  Humble- 
bee,  in  a  state  of  violent  excitement,  communicated  to  three  cubic  inches  of  air 
as  much  as  4°  of  heat  within  five  minutes ;  its  own  temperature  being  raised  7° 
in  the  same  time.  When  several  individuals  in  a  state  of  excitement,  however, 
are  clustered  together,  so  that  the  loss  of  heat  is  prevented,  the  elevation  of 
temperature  is  much  more  considerable;  thus,  a  thermometer  introduced  among 
seven  "  nursing-bees"  stood  at  92  £°,  whilst  the  external  air  was  only  70°;  and 
the  temperature  of  a  hive  was  raised  by  disturbing  it,  during  winter,  from  48  £° 
to  102°,  the  temperature  of  the  air  being  only  34£°  at  the  time. — In  all  these 
instances,  the  amount  of  Oxygen  consumed  bears  an  exact  proportion  to  that  of 
the  Heat  evolved. 

these  spadixes,  hour  by  hour,  during  the  "paroxysm"  of  flowering,  and  the  quantity  of 
oxygen  consumed  during  the  same  periods,  with  the  following  result;  the  amount  of  heat 
developed  being  expressed  by  the  number  of  degrees  (Cent.)  shown  by  the  thermometer 
above  the  temperature  of  the  surrounding  air,  and  the  quantity  of  oxygen  consumed  being 
stated  in  multiples  of  the  volume  of  each  spadix. 


No.  1. 

No.  2. 

No.  3. 

Heat 
produced. 

Oxygen 
consumed. 

Heat 

produced. 

Oxygen 
consumed. 

Heat 
produced. 

Oxygen 
consumed. 

1st  hour 

3.2 

1.11 

4.2 

16.5 

3.5 

10.0 

2d  hour 

5.3 

16.2 

7.2 

21.1 

6.1 

15.5 

3d  hour 

7.8 

21.4 

9.8 

27.7 

8.6 

21.1 

4th  hour 

8.3 

28.5 

8.4 

18.9 

10.2 

31.1 

5th  hour 

6.0 

14.2 

4.8 

12.2 

9.8 

18.9 

6th  hour 

2.7 

5.7 

2.7 

5.5 

5.7 

7.7 

Mean  .         .         .         . 

6.5 

16.1 

6.1 

16.9 

7.3 

17.3 

1  "Philosophical  Transactions,"  1837. 


EVOLUTION    OF    HEAT.  623 

656.  We  have  seen  that  in  Man,  as  in  the  lower  animals,  exercise  has  a  con- 
siderable though  a  more  limited  effect  in  producing  an  elevation  of  temperature; 
and  that  this  is  not  merely  due  to  the  acceleration  of  the  circulation  is  shown 
by  the  fact  that  the  exercise  of  a  particular  muscle  will  cause  an  increase  in 
tfce  heat  liberated  from  it  (§  330). *     It  may  be  stated  as  a  general  fact,  that 
every  change  in  the  condition  of  the  organic  components  of  the  body,  in  which 
their  elements  enter  into  new  combinations  with  oxygen,  must  be  a  source  of 
the  development  of  Heat.     And  as  we  have   seen  that  a  considerable  part  of 
the  carbonic  acid  and  water  which  are  exhaled  in  Respiration,  is  formed  within 
the  body  by  the  metamorphosis  of  its  own  tissues,  and  that  this  metamorphosis 
is  promoted  by  the  active  exercise  of  the  nervo-muscular  apparatus,  it  follows 
that  in  animals  whose  habits  of  life  are  peculiarly  active,  whilst  the  temperature 
of  the  surrounding  medium  is  sufficiently  high  to  prevent  its  exerting  any  con- 
siderable cooling  influence  over  them,  the  combustive  process  thus  maintained 
may  be  adequate  for  the  maintenance  of  the  temperature  of  the  body  at  its  nor- 
mal standard.     This  seems  to  be  the  case  with  the  great  Carnivorous  quad- 
rupeds of  warm  climates,  and  with  certain  races  of  Men  who  lead  a  life  of 
incessant  activity  like  theirs.      But  whenever   the   cooling   influence  of  the 
atmosphere  is  greater,  or  the  retrograde  metamorphosis  of  tissue  takes  place  with 
less  activity,  some  further  supply  of  heat-producing  material  is  required ;  and 
this  is  derived  either  directly  from  the  food,  or  from  a  store  previously  laid  up 
in  the  body.      Although  the  albuminous  and  gelatinous  components  of  the 
food  may  be  made,  by  decomposition  within  the  body,  to  yield  saccharine  and 
oleaginous  compounds,  which  serve  as  an  immediate  pabulum  to  the  combus- 
tive process,  yet  this  metamorphosis  involves  a  great  waste  of  valuable  nutritive 
material ;  and  the  needed  supply  is  much  more  advantageously  derived  at  once 
from  those  farinaceous  or  oleaginous  substances  which  are  furnished  in  abun- 
dance by  the  Vegetable  kingdom,  the  latter  also  by  the  Animal.     No  reasonable 
doubt  can  any  longer  be  entertained,  that  the  production  of  Heat  by  the  com- 
bustive process  is  the  purpose  to  which  these  substances  are  destined  to  be 
subservient  in  the  bodies  of  Herbivorous  animals  and  of  Man;  and  the  results 
of  experience  in  regard  to  their  relative  heat-producing  powers  are  in  precise 
accordance  with  the  indications  afforded  by  their  chemical  composition  (§  401). 

657.  Our  knowledge  of  the  dependence  of  all  the  vital  processes  in  warm- 
blooded animals  upon  the  Heat  of  their  bodies,  and  of  the  dependence  of  their 
calorifying  power  upon  the  due  supply  of  material  for  the  combustive  process, 
has  received  some  remarkable  additions  from  the  experiments  of  M.  Chossat 
upon  Starvation.3  He  found  that  Birds,  when  totally  deprived  of  food  and  drink, 
suffered  a  progressive,  though  slight,  daily  diminution  of  temperature.     This 
diminution  was  not  so  much  shown  by  a  fall  of  their  maximum  heat,  as  by  an 
increase  in  the  diurnal  variation,  which  he  ascertained  to  occur  even  in  the  nor- 
mal state  (§  651,  6).     The  average  variation  in  the  inanitiated  state  was  about 
6°  (instead  of  1J°),  gradually  increasing  as  the  animal  became  weaker;  more- 
over, the  gradual  rise  of  temperature,  which  should  have  taken  place  between 
midnight  and  noon,  was  retarded;  whilst  the  fall  subsequently  to  noon  com- 
menced much  earlier  than  in  the  healthy  state;  so  that  the  average  of  the  whole 
day  was  lowered  by  about  4 2°  between  the  first  and  the  penultimate  days  of  this 

1  It  was  affirmed  by  Dr.  Granville  ("Phil.  Trans.,"  1825)  that  the  temperature  of  the 
uterus  during  parturition  sometimes  rises  as  high  as  120°.     In  some  observations  made  at 
the  Philadelphia  Hospital,  however,  at  the  desire  of  Prof.  Dunglison,  the  temperature  of 
the  uterus  was  not  found  to  be  much  above  that  of  the  vagina ;  the  former  being,  in  three 
cases,  100°,  102°,  and  100°,  whilst  the  latter  was  100°,  100°,  and  105°.  (Prof.  Dunglison's 
"Human  Physiology,"  7th  edit.,  vol.  ii.  p.  226.) 

2  "Recherches  Experimentales  sur  1'Inanition,"  Paris,  1843;  an  analysis  of  this  work 
will  be  found  in  the  "Brit,  and  For.  Med.  Rev.,"  April,  1844. 


624  EVOLUTION   OF   HEAT,    LIGHT,    AND    ELECTRICITY. 

condition.  On  the  last  day,  the  production  of  heat  diminished  very  rapidly, 
and  the  thermometer  fell  from  hour  to  hour,  until  death  supervened;  the  whole 
loss  on  that  day  being  about  25°  Fahr.,  making  the  total  depression  about  29  2°. 
This  depression  appears,  from  the  considerations  to  be  presently  stated,  to  be  the 
immediate  cause  of  Death.  On  examining  the  amount  of  loss  sustained  by  tke 
different  organs  of  the  body,  it  was  found  that  93  per  cent,  of  the  Fat  had  dis- 
appeared; being  all,  in  fact,  which  could  be  removed;  whilst  the  nervous  centres 
scarcely  exhibited  any  diminution  in  weight  (§  416).  From  the  constant  coinci- 
dence between  the  entire  consumption  of  the  fat,  and  the  depression  of  tempera- 
ture— joined  to  the  fact  that  the  duration  of  life  under  the  inanitiating  process 
evidently  varied  (other  things  being  equal)  with  the  amount  of  fat  previously 
accumulated  in  the  body — the  inference  seems  irresistible,  that  the  calorifying 
process  depended  chiefly,  if  not  entirely,  on  the  materials  supplied  by  this  sub- 
stance. Whenever,  therefore,  the  store  of  combustible  matter  in  the  system 
was  exhausted,  the  inanitiated  animals  died,  by  the  cooling  of  their  bodies  con- 
sequent upon  the  loss  of  calorifying  power. 

658.  That  this  is  the  real  explanation  of  the  fact  is  shown  by  the  results  of 
a  series  of  very  remarkable  experiments  performed  by  M.  Chossat,  with  the  purpose 
of  testing  the  correctness  of  this  view.     When  inanitiated  animals  whose  death 
seemed  impending  (in  several  instances  death  actually  took  place,  whilst  the 
preliminary  processes  of  weighing,  the  application  of  the  thermometer,  &c.,  were 
being  performed),  were  subjected  to  artificial  heat,  they  were  almost  uniformly 
restored  from  a  state  of  insensibility  and  want  of  muscular  power  to  a  condition 
of  comparative  activity ;  their  temperature  rose,  their  muscular  power  returned, 
they  flew  about  the  room  and  took  food  when  it  was  presented  to  them ;  and  if 
the  artificial  assistance  was  sufficiently  prolonged,  and  they  were  not  again  sub- 
jected to  the  starving  process,  most  of  them  recovered.     If  they  were  left  to 
themselves  too  early,  however,  the  digestive  process  was  not  performed,  and  they 
ultimately  died.     Up  to  the  time  when  they  began  to  take  food,  their  weight 
continued  to  diminish;  the  secretions  being  renewed,  under  the  influence  of 
artificial  heat,  sometimes  to  a  considerable  amount.     It  was  not  until  digestion 
had  actually  taken  place  (which,  owing  to  the  weakened  functional  power,  was 
commonly  many  hours  subsequently  to  the  ingestion  of  the  food),  that  the 
animal  regained  its  power  of  generating  heat ;  so  that,  if  the  external  source  of 
heat  was  withdrawn,  the  body  at  once  cooled ;  and  it  was  not  until  the  quantity 
of  food  actually  digested  was  sufficient  to  support  the  wants  of  the  body,  that 
its  independent  power  of  calorification  returned.     It  is  to  be  remembered  that, 
in  such  cases,  the  resources  of  the  body  are  on  the  point  of  being  completely 
exhausted,  when  the  attempt  at  re-animation  is  made;    consequently  it  has 
nothing  whatever  to  fall  back  upon ;  and  the  leaving  it  to  itself  at  any  time 
until  fresh  resources  have  been  provided  for  it,  is  consequently  as  certain  a 
cause  of  death,  as  it  would  have  been  in  the  first  instance. 

659.  It  can  scarcely  be  questioned,  from  the  similarity  of  the  phenomena, 
that  Inanitiation,  with  its  consequent  depression  of  temperature,  is  the  imme- 
diate cause  of  death  in  various  diseases  of  Exhaustion  :  and  it  seems  probable 
that  there  are  many  cases,  in  which  the  depressing  cause  is  of  a  temporary 
nature,  and  in  which  a  judicious  and  timely  application  of  artificial  heat  might 
prolong  life  until  it  has  passed  off,  just  as  artificial  respiration  is  serviceable  in 
cases  of  narcotic  poisoning  (§  208).     It  is  especially,  perhaps,  in  those  forms  of 
Fever,  in  which  no  decided  lesion  can  be  discovered  after  death,  that  this  view 
has  the  strongest  claim  to  reception ;  and  the  beneficial  result  of  the  adminis- 
tration of  Alcohol  in  such  conditions,  and  the  large  amount  in  which  it  may  be 
given  with  impunity,  may  probably  be  accounted  for  on  this  principle.     That 
it  acts  as  a  specific  stimulus  to  the  nervous  system,  cannot  be  doubted  from  its 
effects  on  the  healthy  body ;  but  that  it  serves  as  a  fuel  to  keep  up  the  calori- 


EVOLUTION   OF   HEAT.  625 

fying  process,  appears  equally  certain.  Its  great  efficacy  in  such  cases  seems 
to  depend  upon  the  readiness  with  which  it  will  be  taken  into  the  circulation 
by  a  simple  act  of  endosmotic  imbibition,  when  the  special  Absorbent  process, 
dependent  upon  the  peculiar  powers  of  the  cells  of  the  villi  (§  461),  are  in 
abeyance.  There  is  no  other  combustible  fluid,  whose  miscibility  and  whose 
density,  relatively  to  that  of  the  Blood,  will  permit  of  its  rapid  absorption  by 
the  simple  physical  process  adverted  to.1 

660.  That  the  oxidation  of  certain  components  of  the  food  or  of  the  tissues 
is  the  fundamental  source  of  Animal  Heat,  is  further  indicated  by  the  close 
conformity  which  we  everywhere  find  between  the  activity  of  the  Respiratory 
process  and  the  amount  of  Heat  which  is  generated  •  and  this  not  merely  when 
we  compare  different  tribes  of  animals  with  each  other,  but  also  when  we  com- 
pare the  amount  of  oxygen  absorbed  and  of  carbonic  acid  exhaled  by  the  same 
individuals  under  different  degrees  of  external  temperature  (§  564,  a).  For 
we  find  that  the  system  possesses  within  itself  a  regulating  power,  by  which  the 
combustive  process  is  augmented  in  activity  when  the  cooling  influence  of  the 
surrounding  medium  is  considerable,  so  that  this  influence  is  resisted ;  whilst 
the  internal  fire  (so  to  speak)  is  slackened,  whenever  the  temperature  of  the 
outer  air  rises  so  much,  as  to  render  the  same  generation  of  heat  no  longer  re- 
quisite. The  appetite  for  food,  and  especially  for  those  particular  forms  of  it 
which  best  afford  the  combustive  pabulum,  varies  in  the  same  degree ;  and  thus, 
when  supplied  with  appropriate  nutriment,  Man  is  able  to  brave  the  severest 
cold,  without  suffering  any  considerable  depression  in  his  bodily  temperature. 
— It  would  seem  that  the  Cutaneous  Respiration,  small  as  it  is,  promotes  those 
molecular  changes  on  which  the  maintenance  of  Animal  Heat  depends  ;  for  it 
was  found  by  MM.  Becquerel  and  Breschet,2  that  when  the  hair  of  Rabbits  was 
shaved  off,  and  a  composition  of  glue,  suet,  and  resin  (forming  a  coating 
impermeable  to  the  air)  was  applied  to  the  whole  surface,  the  temperature 
rapidly  fell,  notwithstanding  the  obstacle  thus  offered  to  the  evaporation  of  the 
sweat,  whereby,  it  might  be  supposed,  the  temperature  of  the  body  would  be 
considerably  elevated.  In  the  first  rabbit,  which  had  a  temperature  of  100° 
before  being  shaved  and  plastered,  it  had  fallen  to  89 £°  by  the  time  the  mate- 
rial spread  over  him  was  dry.  An  hour  after,  the  thermometer  placed  in  the 
same  parts  (the  muscles  of  the  thigh  and  chest)  had  descended  to  76°.  In 
another  rabbit,  prepared  with  more  care,  by  the  time  that  the  plaster  was  dry, 
the  temperature  of  the  body  was  not  more  than  5J°  above  that  of  the  surround- 
ing medium,  which  was  at  that  time  69  J°;  and  in  an  hour  after  this,  the  ani- 
mal died. — These  experiments  place  in  a  very  striking  point  of  view  the  im- 
portance of  the  cutaneous  surface  as  a  respiratory  organ,  even  in  the  higher 
animals ;  and  they  enable  us  to  understand  how,  when  the  secreting  power  of 
the  lungs  is  nearly  destroyed  by  disease,  the  heat  of  the  body  is  kept  up  to  its 
natural  standard  by  the  action  of  the  Skin.  A  valuable  therapeutic  indication, 
also,  is  derivable  from  the  knowledge  which  we  thus  gain,  of  the  importance  of 
the  cutaneous  respiration ;  for  it  leads  us  to  perceive  the  desirableness  of  keep- 
ing the  skin  moist,  in  those  febrile  diseases  in  which  there  are  great  heat  and 
dryness  of  the  surface,  since  secretion  cannot  properly  take  place  through  a  dry 
membrane.  Of  the  relief  afforded  by  cold  or  tepid  sponging  in  such  cases, 
experience  has  given  ample  evidence. 

661.  It  has  been  held  that  the  Chemical  theory  of  Calorification  is  insufficient 

1  The  Author  has  stated  the  very  striking  results  of  observations  which  he  has  had  the 
opportunity  of  making  upon  this  point,  in  his  Prize  Essay  "On  the  Use  and  Abuse  of 
Alcoholic  Liquors,"  %  215,  Am.  Ed, 

2  "Comptes  Rendus,"  Oct.,  1841.     These  experiments  have  been  repeated  and  con- 
firmed by  Magendie  ("Gazette  Medicale,"  Dec.  6,  1843). 

40 


626  EVOLUTION    OF   HEAT,    LIGHT,    AND   ELECTRICITY. 

to  account  for  the  total  amount  of  Heat  generated  by  a  warm-blooded  animal 
in  a  given  time ;  this  assertion  being  founded  upon  the  experimental  results 
obtained  by  M.  Dulong.  It  has  been  shown  by  Prof.  Liebig,  however,  that  the 
estimates  originally  made  require  correction  for  the  true  calorific  equivalents  of 
carbon  and  hydrogen  ;  and  that,  this  correction  having  been  made,  the  heat 
produced  by  the  combustion  of  the  Carbon  which  is  contained  in  the  carbonic 
acid  expired,  and  by  the  combustion  of  such  a  proportion  of  the  Hydrogen  con- 
tained in  the  exhaled  water  as  may  be  fairly  considered  to  have  undergone 
oxygenation  within  the  system  (§  569),  proves  to  be  adequate  to  compensate 
for  that  which  would  be  dissipated  by  the  evaporation  of  all  the  water  trans- 
pired from  the  skin  and  lungs,  and  also  to  maintain  the  temperature  of  the 
body  itself  in  an  atmosphere  of  ordinary  coolness.1  And  to  the  combustion 
heat  of  carbon  and  hydrogen,  we  should  also  add  that  of  those  relatively  minute 
quantities  of  Phosphorus  and  Sulphur,  which  also  undergo  oxidation  within  the 
system,  whereby  a  small  additional  amount  of  heat  must  be  generated. — Through 
whatever  diversity  of  combinations  or  successive  stages  of  oxidation  these  ele- 
ments respectively  pass,  in  their  progress  to  complete  or  final  oxidation,  it  may 
be  regarded  as  an  indisputable  fact,  that  they  give  out  precisely  the  same  amount 
of  heat  in  the  whole,  as  if  they  had  undergone  the  most  rapid  combustion  in  pure 
oxygen  ;  and  thus  we  may  look  to  almost  every  molecular  change  in  the  body, 
although  pre-eminently  to  those  which  are  concerned  in  the  disintegration  of  its 
textures  and  in  the  elimination  of  their  products  by  Respiration,  as  participating 
in  the  function  of  Calorification. 

662.  It  cannot  be  denied,  however,  that  there  are  certain  phenomena  which 
seem  at  first  sight  to  be  completely  opposed  to  this  doctrine,  and  which  can 
scarcely  be  explained  in  accordance  with  it,  save  by  a  considerable  modification 
in  our  usual  ideas.  The  class  of  facts  to  which  reference  is  here  made,  are 
those  which  indicate  that  the  Nervous  system  has  a  very  important  concern  in 
the  process,  and  that  it  is,  in  fact,  one  of  the  immediate  instruments  in  the 
development  of  heat.  Thus  it  was  experimentally  shown  by  Sir  B.  Brodie,2 
that  when  the  Brain  is  cut  off  from  the  spinal  cord,  or  its  functions  are  sus- 
pended by  the  agency  of  a  narcotic,  and  artificial  respiration  is  practised,  so  that 
the  circulation  is  maintained,  the  body  not  only  loses  heat  rapidly,  but  may 
even  cool  more  rapidly  than  the  body  of  an  animal  similarly  treated,  but  in 
which  artificial  respiration  is  not  performed.  Now  it  is  certainly  true,  as  was 
subsequently  pointed  out  by  Drs.  Wilson  Philip  and  Hastings,3  and  by  Dr.  C. 
Williams,4  that  the  effect  of  the  artificial  performance  of  respiration  depends  in 
some  degree  upon  the  mode  in  which  it  is  accomplished;  for  that  if,  as  in  most 
of  Sir  B.  Brodie's  experiments,  the  insufflation  be  repeated  30  times  or  more 
in  a  minute,  the  cooling  effect  of  the  air  thus  introduced  is  greater  than  the 
warming  effect  of  the  imperfect  respiratory  change  to  which  it  becomes  subser- 
vient; whilst  if  the  insufflation  be  repeated  only  12  times  in  a  minute,  the 
cooling  of  the  body,  as  compared  with  that  of  a  body  in  which  the  circulation 
is  not  thus  maintained,  is  retarded,  instead  of  being  accelerated.  But  still  it  is 
evident  from  Sir  B.  Brodie's  experiments,  that  the  withdrawal  of  the  influence 
of  the  Encephalon  has  a  positively  depressing  effect  upon  the  Calorific  function ; 
for  the  rapid  fall  of  temperature  took  place  even  in  cases  in  which  the  amount 
of  carbonic  acid  exhaled  during  the  performance  of  artificial  respiration,  was 
fully  equal  to  the  normal  quantity;  and  the  subsequent  experiments  of  MM. 

1  See  P.  of  Liebig's  "Animal  Chemistry,"  3d  edit.,  p.  44. 

2  "Philosophical  Transactions,"  1811,  1812;  and  "Physiological  Researches." 

3  See  Dr.  Wilson  Philip's  "Experimental  Inquiry  into  the  Laws  of  the  Vital  Functions," 
3d  edit.,  p.  180. 

«  "Ediub.  Med.-Chir.  Trans.,"  vol.  ii.  p.  192. 


EVOLUTION   OP   HEAT.  627 

Le  Gallois1  and  Chossat3  are  decidedly  confirmatory  of  this  conclusion,  whilst 
they  extend  it  to  other  lesions  of  the  Nervous  centres,  the  influence  of  which 
upon  the  calorific  function  appears  to  be  proportional  to  their  severity. — Various 
pathological  phenomena,  moreover,  indicate  that  the  withdrawal  of  nervous  in- 
fluence from  any  part  of  the  body  usually  tends  to  produce  a  depression  of  its 
temperature,  and  this  especially  in  the  extremities;  thus,  Mr.  H.  Earle3  found 
the  temperature  of  paralyzed  limbs  slightly  lower  than  that  of  sound  limbs ;  so 
Prof.  Dunglison  has  noticed  that  in  one  case  of  hemiplegia  of  five  months'  stand- 
ing, the  temperature  of  the  axilla  was  96£°  on  the  sound  side,  and  96°  on  the 
paralyzed,  whilst  that  of  the  hand  was  87°  on  the  sound  side  and  only  79  J°  on 
the  paralyzed;  and  in  another  case  of  only  a  fortnight's  duration,  the  tempera- 
ture of  the  axilla  was  100°  on  the  sound  side,  and  only  98  i°  on  the  paralyzed, 
whilst  that  of  the  hand  was  94°  on  the  sound  side,  and  90°  on  the  paralyzed.4 
But  it  is  a  remarkable  fact,  that  the  disturbance  of  temperature  produced  by 
severe  injuries  of  the  Nervous  system  occasionally  shows  itself  in  the  opposite 
direction.  Thus,  it  has  been  noticed  by  many  experimenters  that  one  of  the  first 
effects  of  division  of  the  spinal  cord  in  the  back,  in  warm-blooded  animals,  is  to 
raise  the  temperature  of  the  posterior  part  of  the  body,  this  elevation  continu- 
ing for  some  hours.  A  case  is  recorded  by  Sir  B.  Brodie,  in  which,  the  spinal 
cord  having  been  so  seriously  injured  in  the  lower  part  of  the  cervical  region 
that  the  whole  of  the  nerves  passing  off  below  were  completely  paralyzed,  the 
heat  of  the  body,  as  shown  by  a  thermometer  placed  on  the  inside  of  the  groin, 
was  not  less  than  111°;  and  this  notwithstanding  that  the  respiratory  function 
was  very  imperfectly  performed,  the  number  of  inspirations  being  considerably 
reduced,  and  the  countenance  being  livid.5  And  Prof.  Dunglison  states  that, 
notwithstanding  the  usual  depression  of  the  thermometer  on  the  hemiplegic 
side,  it  is  not  unfrequently  found  to  be  more  elevated  than  on  the  sound  side.6 
According  to  the  recent  experiments  of  M.  Cl.  Bernard,7  it  appears  that  an  ele- 
vation of  temperature  constantly  takes  place  on  one  side  of  the  face,  when  the 
trunk  which  unites  the  Sympathetic  ganglia  of  the  neck  on  that  side  is  cut 
through;  this  increase  being  not  only  perceptible  to  the  touch,  but  showing 
itself  by  a  thermometer  introduced  into  the  nostrils  or  ears,  even  to  the  extent 
of  from  7°  to  11°  Fahr.  When  the  superior  cervical  ganglion  is  removed,  the 
same  effect  is  produced,  but  with  yet  greater  intensity.  This  difference  is  main- 
tained for  many  months,  and  is  not  connected  with  the  occurrence  of  inflamma- 
tion, congestion,  oedema,  or  any  other  pathplogical  change  in  the  part ;  more- 
over, it  is  not  prevented  from  manifesting  itself  by  the  division  of  any  of  the 
cerebro-spinal  nerves  of  the  face.  It  is  remarkable  that  the  sensibility  of  the 
parts  thus  affected  should  be  no  less  augmented  than  their  temperature. 

[Dr.  Brown-Sequard  has  observed  the  same  remarkable  phenomena  as  those 
detailed  by  M.  Cl.  Bernard,  but  he  regards  them  as  mere  results  of  the 
paralysis,  and  of  the  consequent  dilatation  of  the  bloodvessels.  In  conse- 
quence of  this  dilatation,  the  blood  reaches  the  part  supplied  by  the  nerve  in 
larger  quantities;  the  nutrition  is  therefore  more  active.  The  increased  sensi- 
bility is  a  result  of  the  augmented  vital  properties  of  the  nerves  when  their 
nutrition  is  increased.  Dr.  Brown-Sequard  has  likewise  noticed  the  increase  of 
temperature  of  the  ear  over  that  of  the  rectum,  to  the  amount  of  one  or  two 
degrees  Fahr.;  but  it  must  be  remembered  that  the  temperature  of  the  rectum 
is  a  little  lower  than  that  of  the  blood,  and  as  the  ear  is  gorged  with  that  fluid,  it 

1  "  Annales  de  Chimie,"  1817;  and  "(Euvres  de  M.  Le  Gallois,"  torn.  ii. 

2  "Memoire  sur  1'Influence  de  Systeme  Nerveux  sur  la  Chaleur  Animale." 

3  "  Medico-Chirurgical  Transactions,"  vol.  vii. 

*  "Human  Physiology,"  7th  edit.,  vol.  ii.  p.  238. 

6  "Medical  Gazette,"  June,  1836;  and  "Physiological  Researches,"  p.  121. 

6  "Amer.  Med.  Intelligencer,"  Oct.  18,  1838.     1  "Gazette  Medicale,"  Fevr.  21,  1852. 


628  EVOLUTION   OP    HEAT,    LIGHT,    AND   ELECTRICITY. 

is  easy  to  understand  why  it  should  possess  its  temperature.  Many  facts  prove 
that  the  degree  of  temperature  and  sensibility  in  a  part  are  in  direct  ratio  with 
the  amount  of  blood  circulating  in  it. 

If  galvanism  be  applied  to  the  superior  portion  of  the  sympathetic  nerve 
after  it  has  been  cut  in  the  neck,  the  vessels  of  the  face  and  ear,  after  a  short 
time,  begin  to  contract,  and  subsequently  resume  their  normal  condition,  if  they 
do  not  even  diminish.  Coincidently  with  this  diminution,  there  is  a  decrease  of 
the  temperature  and  sensibility  of  the  face  and  ear,  until  the  palsied  and  sound 
side  are  alike  in  this  respect. 

When  the  galvanic  current  ceases  to  act,  the  vessels  again  dilate,  and  all  the 
phenomena  discovered  by  M.  Bernard  reappear.  It  hence  appears  that  the 
only  direct  effect  of  section  of  the  cervical  portion  of  the  sympathetic  is  the 
paralysis  and  consequent  dilatation  of  the  bloodvessels.  Another  deduction 
from  these  experiments  is,  that  the  sympathetic  sends  motor  fibres  to  many  of 
the  bloodvessels  of  the  head.1] 

663.  The  influence  which  conditions  of  the  Nervous  System  are  thus  shown 
to  possess  over  the  function  of  Calorification  has  led  some  Physiologists  and 
even  Chemists  to  the  conclusion  that  the  production  of  Heat  is  essentially  de- 
pendent upon  Nervous  agency,  of  which  it  is  one  of  the  manifestations.  But, 
as  Prof.  Liebig  justly  observes,  "if  this  view  exclude  chemical  action,  or  changes 
in  the  arrangement  of  the  elementary  particles,  as  a  condition  of  nervous  agency, 
it  means  nothing  else  than  to  derive  the  presence  of  motion,  the  manifestation 
of  force,  from  nothing.  But  no  force,  no  power,  can  come  of  nothing."2  That 
the  production  of  heat  in  living  bodies  may  take  place  without  any  possible 
assistance  from  nervous  agency,  is  manifest  from  the  phenomena  of  Vegetable 
heat  already  referred  to  (655) ;  and  there  can  be  no  reasonable  doubt,  that  the 
source  of  this  production  is  a  true  combustive  process.  And  the  evidence  afforded 
by  the  post-mortem  production  of  heat  in  the  Human  subject  (§  652)  conclu- 
sively points  to  the  same  result;  more  particularly  as  the  elevation  of  tempera- 
ture observed  in  the  brain  was  uniformly  less  than  that  which  was  manifested 
in  other  large  organs. — But  the  phenomena  just  enumerated  (and  many  others 
that  might  be  cited)  can  scarcely  be  accounted  for,  without  admitting  that  the 
Nervous  system  exerts  an  important  modifying  power  upon  the  temperature  of 
the  body,  which  may  be  either  elevated  or  depressed  through  its  agency ;  and 
the  question  now  arises  whether  this  operation  takes  place  through  the  influence 
which  the  Nervous  system  exerts  over  the  molecular  processes  of  Nutrition,  Se- 
cretion, &c.,  or  through  some  more  direct  method.  It  can  scarcely  be  denied 
that  the  first  of  these  channels  affords  not  merely  a  possible,  but  also  a  probable 
means,  for  the  exercise  of  such  influence;  but  still  it  is  difficult  to  conceive 
that  any  great  effect  can  be  thus  produced,  since,  as  already  shown,  it  is  not 
so  much  in  the  growth  as  in  the  disintegration  of  textures,  that  heat  is  pro- 
duced by  the  oxidation  of  their  components.  On  the  other  hand,  from  the 
close  relation  which  has  been  shown  to  exist  between  the  Vital  and  Physical 
forces  (CHAP.  in.  SECT.  2),  -it  can  scarcely  be  regarded  as  improbable  that  the 
Nervous  force,  generated  by  molecular  changes  in  the  Nervous  substance,  may 
manifest  itself  under  the  form  of  Heat,  just  as  we  know  that  it  manifests  itself 
(as  in  the  Electric  fishes)  under  that  of  Electricity.3  And  thus  it  is  quite  con- 
ceivable that  one  mode  in  which  alimentary  materials  may  be  applied  to  the 
maintenance  of  Animal  Heat,  may  consist  in  their  subservience  to  these  mole- 
cular changes,  which  seem  to  take  place  in  the  Nervous  substance  with  more 
activity  than  in  any  other  tissue;  and  thus  a  large  measure  of  caloric  may  be 

1  Vide  Phil.  Med.  Exam.,  N.  S.,  vol.  viii.  No.  viii.,  August,  1852. 

2  "Animal  Chemistry,"  3d  edit.,  p.  39. 

3  See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  \\  635-639,  Am.  Ed. 


EVOLUTION    OF   HEAT.  629 

generated  through  the  immediate  instrumentality  of  the  Nervous  system,  not- 
withstanding that  the  ultimate  source  of  its  development  lies  (as  in  the  Chemi- 
cal theory)  in  the  oxidation  of  the  elements  of  the  food. — Such  an  hypothesis 
will  be  found  consistent,  the  Author  believes,  with  all  the  well-ascertained  facts 
of  the  case;  for  whilst  it  assigns  their  full  value  to  all  those  proofs,  which  estab- 
lish (in  his  mind)  the  necessary  dependence  of  Calorification  upon  the  changes 
to  which  the  Inspiration  is  subservient,  and  thus  upon  the  supply  of  combus- 
tive  material  on  the  one  hand,  and  of  oxygen  on  the  other,  it  also  assigns  a  defi- 
nite modus  operandi  to  the  Nervous  system,  as  an  instrument  largely  concerned 
in  the  production  and  distribution  of  the  heat  thus  generated — this  modus  ope- 
randi, moreover,  being  in  such  complete  harmony  with  the  other  manifestations 
of  Nervous  power,  that  its  existence  might  almost  have  been  predicated  upon 
general  considerations.1 

664.  We  have  now  to  inquire  whether  the  power  of  generating  Heat  is  pos- 
sessed by  the  Human  subject  in  an  equal  degree  at  all  ages;  this  question  being 
very  different  from  that  of  the  usual  temperature  of  the  body  at  the  various 
periods  of  life;  since  an  individual  who  can  maintain  a  high  temperature  when 
the  surrounding  air  is  moderately  warm,  may  have  very  little  $ower  of  bearing 
continued  exposure  to  severe  cold.  Important  analogical  evidence  on  this  point 
has  been  supplied  by  the  experiments  of  Dr.  W.  F.  Edwards  upon  the  lower 
Mammalia,  Birds,  &c.3  It  appears  from  these  to  be  a  general  fact  that,  the 
younger  the  animal,  the  less  is  its  independent  calorifying  power.  The  de- 
velopment of  the  embryo  of  oviparous  animals  is  entirely  dependent  upon  the 
amount  of  external  warmth  supplied  to  it ;  and  there  are  many  kinds  of  Birds, 
which,  at  the  time  they  issue  from  the  egg,  are  so  deficient  in  the  power  of 
generating  heat,  that  their  temperature  rapidly  falls  when  they  are  removed 
from  the  nest  and  placed  in  a  cold  atmosphere.  It  was  shown  by  collateral  ex- 
periments, that  the  loss  of  heat  was  not  to  be  attributed  to  the  absence  of  fea- 
thers, nor  to  the  extent  of  surface  exposed  in  comparison  with  the  bulk  of  the 
body;  and  that  nothing  but  an  absolute  deficiency  in  the  power  of  generating  it, 
would  account  for  the  fall  of  temperature.  This  is  quite  conformable  to  facts 
well  ascertained  in  regard  to  Mammalia.  The  foetus,  during  intra-uterine  life, 
has  little  power  of  keeping  up  its  own  temperature ;  and  in  many  cases  it  is 
much  dependent  on  external  warmth,  for  some  time  after  birth.  The  degree  of 
this  dependence,  however,  differs  greatly  in  the  various  species  of  Mammalia; 
as  among  Birds ;  being  less  in  proportion  as  the  general  development  is  advanced. 
Thus,  young  Guinea-pigs,  which  can  run  about  and  pick  up  food  for  themselves, 
almost  as  soon  as  they  are  born,  are  from  the  first  independent  of  parental 
warmth;  whilst,  on  the  other  hand,  the  young  of  Dogs,  Cats,  Rabbits,  &c.,  which 
are  born  blind,  and  which  do  not,  for  a  fortnight  or  more,  acquire  the  same  de- 
velopment with  the  preceding,  rapidly  lose  their  heat  when  withdrawn  from 
contact  with  the  body  of  the  mother. — In  the  Human  species,  it  is  well  known 
that  external  warmth  is  necessary  for  the  Infant,  its  body  rapidly  losing  heat 
when  exposed  to  the  chilling  influence  of  a  low  temperature ;  but  the  fact  is  too 
often  neglected  (under  the  erroneous  idea  of  hardening  the  constitution)  during 
the  early  years  of  childhood.  It  is  to  be  carefully  remembered,  that  the  develop- 
ment of  Man  is  slower  than  that  of  any  other  animal,  and  that  his  calorifying 
power  is  closely  connected  with  his  general  bodily  vigor;  and  though  the  infant 
becomes  more  independent  of  it  as  development  advances,  it  is  many  years  before 
the  standard  can  be  maintained  without  assistance,  throughout  the  ordinary 
vicissitudes  of  external  temperature.  Especial  care  is  required  with  regard  to 
the  maintenance  of  the  bodily  heat  by  artificial  warmth,  in  the  case  of  children 

1  See  the  Author's  Memoir  "On  the  Mutual  Relations  of  the  Vital  and  Physical  Forces," 
in  "Phil.  Trans.,"  1850. 

2  "On  the  Influence  of  Physical  Agents  on  Life,"  Part  iii.  Chap.  i. 


630 


EVOLUTION    OF   HEAT,   LIGHT,    AND   ELECTRICITY. 


prematurely  born ;  for  the  earlier  the  period  of  embryonic  life,  the  less  is  the 
power  of  calorification  that  exists  for  some  time  after  birth.  The  temperature 
of  a  seven  months'  child,  though  well  swathed  and  near  a  good  fire,  was  found 
by  Dr.  W.  Edwards,  within  two  or  three  hours  after  its  birth,  to  be  no  more 
than  89.6°.  And  in  some  of  the  recorded  instances  in  which  the  birth  has 
taken  place  before  the  completion  of  the  sixth  month,  it  has  not  been  found 
possible  to  maintain  the  warmth  of  the  infant  by  exposure  to  the  radiant»heat 
of  a  fire,  the  contact  of  the  warm  body  of  another  person  being  the  only  effectual 
means  of  keeping  up  its  temperature. — The  fullest  measure  of  calorifying  power 
is  possessed  by  adults ;  but  even  in  them  it  is  sometimes  weakened  by  previous 
exertion,  so  that  death  by  the  cooling  of  the  body  may  occur  when  the  body  is 
exposed  to  cold  of  no  great  intensity,  but  in  a  state  of  exhaustion  of  nervous 
power ;  a  fact  which  remarkably  confirms  the  views  advanced  in  the  preceding 
paragraph.  A  decrease  of  calorifying  power  takes  place  in  advanced  age.  Old 
people  complain  that  their  "  blood  is  chill  •"  and  they  suffer  greatly  from  ex- 
posure to  cold,  the  temperature  of  the  whole  body  being  lowered  by  it.  These 
facts  have  a  very  interesting  connection  with  the  results  of  statistical  inquiries, 
as  to  the  average  number  of  deaths  at  different  seasons;  the  following  are  re- 
corded by  M.  Quetelet,1  as  occurring  at  Brussels,  the  mean  monthly  mortality 
at  each  age  being  reckoned  as  100. 


First 
Month. 

2—3 
Years. 

8—12 
Years. 

25—30 
Years. 

50—65 
Years. 

90  Years 
and  above. 

January            .  '-i     '    .  ". 

1.39 

1.22 

1.08 

.05 

1.30 

1.58 

February              }*•>    .*   ! 

1.28 

1.18 

1.06 

.04 

1.22 

1.48 

March     '.'  ;  •,'/»••*  i!  iV.J  * 

1.21 

1.30 

1.27 

.11 

1.11 

1.25 

April  .                            »  ,; 

1.02 

1.27 

1.34 

.06 

1.02 

0.96 

May    . 

0.93 

1.12 

1.21 

.02 

0.93 

0.84 

June    .                  . 

0.83 

0.94 

0.99 

1.02 

0.85 

0.75 

July    .                  .        "••/• 

0.78 

0.82 

0.88 

0.91 

0.77 

0.64 

August                 .        c,  -'•>"  • 

0.79 

0.73 

0.82 

0.96 

0.85 

0.66 

September            .       -v.r* 

0.86 

0.76 

0.81 

0.95 

0.89 

0.76 

October 

0.91 

0.78 

0.76 

0.93 

0.90 

0.74 

November 

0.93 

0.91 

0.80 

0.97 

1.00 

1.03 

December 

1.07 

1.01 

0.96  ' 

0.97 

1.15 

1.29 

We  see  from  this  table  that,  during  the  first  months  of  infant  life,  the  external 
temperature  has  a  very  marked  influence;  for  the  average  mortality  during  each 
of  the  three  summer  months  being  80,  that  of  January  is  nearly  140,  and  the 
average  of  February  and  March  is  125.  This  is  confirmed  by  the  result  ob- 
tained by  MM.  Villerme  and  Milne-Edwards  in  their  researches  on  the  mortality 
of  the  children  conveyed  to  the  Foundling  Hospitals  in  the  different  towns  in 
France;  for  they  not  only  ascertained  that  the  mortality  is  much  the  greatest 
during  the  first  three  months  in  the  year,  but  also  that  it  varies  in  different 
parts  of  the  kingdom,  according  to  the  relative  severity  of  the  winter.3  As 
childhood  advances,  however,  the  winter  mortality  diminishes,  whilst  that  of  the 
spring  undergoes  an  increase;  this  is  probably  due  to  the  greater  prevalence  of 
certain  epidemics  at  the  latter  season;  for  the  same  condition  is  observed,  in  a 

1  "Essai  de  Physique  Sociale,"  torn.  i.  p.  197. 

2  Dr.  Emerson  has  shown  that,  in  the  Southern  and  Middle  States  of  North  America, 
the  high  summer  temperature  is  the  greatest  cause  of  infant  mortality;  the  proportion  of 
deaths  during  the  first  year  of  childhood,  occurring  in  the  months  of  June,  July,  and 
August,  being  about  four  times  greater  than  that  occurring  during  the  same  months  in 
any  subsequent  year  up  to  the  age  of  20.     The  winter  mortality  under  the  second  year 
scarcely  exceeds  the  average  of  subsequent  years.     ("Amer.  Journ.  of  Med.  Sci.,"  Nov. 
1831.) 


EVOLUTION   OF   HEAT.  631 

still  more  remarkable  degree,  between  the  ages  of  8  and  12  years — the  time 
when  children  are  most  severely  affected  by  such  epidemics.  As  the  constitution 
acquires  greater  vigor,  and  the  bodily  structure  attains  its  full  development,  the 
influence  of  the  season  upon  mortality  becomes  less  apparent;  so  that,  at  the  age 
of  from  25  to  30  years,  the  difference  between  the  summer  and  winter  mortality 
is  very  slight.  This  difference  reappears,  however,  in  a  very  marked  degree,  at 
a  later  period,  when  the  general  vigor  and  the  calorifying  power  undergo  a 
gradual  diminution.  Between  the  ages  of  50  and  65  it  is  nearly  as  great  as  in 
early  infancy;  and  it  gradually  becomes  more  striking,  until,  at  the  age  of  90 
and  upwards,  the  deaths  in  January  are  158  for  every  74  in  July  (a  proportion 
of  2  £  to  1);  and  the  average  of  the  three  winter  months  is  145,  whilst  that  of 
the  three  summer  months  is  only  68,  or  less  than  one-half. — The  results  of  the 
comparisons  which  have  now  been  carried  out  for  many  successive  years,  in  the 
Reports  of  the  Registrar-G-eneral,  between  the  variations  in  the  weekly  rate  of 
mortality  in  the  metropolis  and  the  range  of  atmospheric  temperature,  present  a 
close  coincidence  with  the  foregoing :  it  being  especially  to  be  noted  that  the  rate 
of  mortality  (save  during  the  prevalence  of  any  fatal  epidemic)  is  almost  invaria- 
bly the  highest  during  the  winter  months ;  that  the  increase  of  deaths  at  that 
period  is  most  marked  amongst  children  and  old  people ;  and  that  any  extraordi- 
nary severity  of  winter  cold  constantly  produces  a  great  augmentation  in  the 
mortality,  the  weekly  number  of  deaths  rising  from,  the  average  of  1000  (or 
thereabouts)  to  1200,  when  the  mean  temperature  of  the  twenty-four  hours  falls 
a  degree  or  two  lower  than  the  freezing-point. 

665.  Having  thus  considered  the  means  by  which  the  degree  of  Heat  neces- 
sary for  the  performance  of  the  functions  of  the  Human  system  is  generated, 
we  have  to  inquire  how  its  temperature  is  prevented  from  being  raised  too  high ; 
in  other  words,  what  frigorifying  means  there  are,  to  counterbalance  the  influ- 
ence of  causes  which,  in  excess,  would  otherwise  be  fatal,  by  raising  the  heat  of 
the  body  to  an  undue  degree  (§  654).  How  is  it,  for  example,  that,  when  a 
person  enters  a  room  whose  atmosphere  is  heated  to  one  or  two  hundred  degrees 
above  his  body,  the  latter  does  not  partake  of  the  elevation,  even  though  ex- 
posed to  the  heat  for  some  time  ?  Or,  since  the  inhabitants  of  a  climate,  where 
the  thermometer  averages  100°  for  many  weeks  together,  are  continually  gene- 
rating additional  heat  in  their  own  bodies,  how  is  it  that  this  does  not  accumu- 
late, and  raise  them  to  an  undue  elevation  ? — The  means  provided  by  Nature  for 
cooling  the  body  when  necessary,  are  of  the  simplest  possible  character.  From 
the  whole  of  its  soft  moist  surface,  simple  Evaporation  will  rake  place  at  all 
times,  as  from  an  inorganic  body  in  the  same  circumstances ;  and  the  amount  of 
this  will  be  regulated  merely  by  the  condition  of  the  atmosphere,  as  to  warmth 
and  dryness.  The  more  readily  watery  vapor  can  be  dissolved  in  atmospheric 
air,  the  more  will  be  lost  from  the  surface  of  the  body  in  this  manner.  In  cold 
weather,  very  little  is  thus  carried  off",  even  though  the  air  be  dry :  and  a  warm 
atmosphere,  already  charged  with  dampness,  will  be  nearly  as  ineffectual.  But 
simple  evaporation  is  not  the  chief  means  by  which  the  temperature  of  the  body 
is  regulated.  The  Skin,  as  already  mentioned  (646),  contains  a  large  number 
of  glandulge,  the  office  of  which  is  to  secrete  an  aqueous  fluid;  and  the  amount 
of  this  Exhalation  appears  to  depend  solely  or  chiefly  upon  the  temperature  of 
the  surrounding  air.  Thus,  when  the  external  heat  is  very  great,  a  considerable 
amount  of  fluid  is  transuded  from  the  skin ;  and  this,  in  evaporating,  carries  off 
a  large  quantity  of  the  free  caloric,  which  would  otherwise  raise  the  temperature 
of  the  body.  If  the  atmosphere  be  hot  and  dry,  and  also  be  in  motion,  both 
exhalation  and  evaporation  go  on  with  great  rapidity.  If  it  be  cold,  both  are 
checked,  the  former  almost  entirely  so;  but,  if  it  be  dry,  some  evaporation  still 
continues.  On  the  other  hand,  in  a  hot  atmosphere,  saturated  with  moisture, 
exhalation  continues,  though  evaporation  is  almost  entirely  checked;  and  the 


632  EVOLUTION   OF   HEAT,   LIGHT,  AND   ELECTRICITY. 

fluid  poured  out  by  the  exhalant  glands  accumulates  on  the  skin.  There  is 
reason  to  believe  that  the  secretion  continues,  even  when  the  body  is  immersed 
in  water,  provided  its  temperature  be  high. — We  learn  from  these  facts  the 
great  importance  of  not  suddenly  checking  Exhalation,  by  exposure  of  the  sur- 
face to  cold,  when  the  secretion  is  being  actively  performed ;  since  a  great  dis- 
turbance of  the  circulation  will  be  likely  to  ensue,  similar  to  that  which  has 
been  already  mentioned,  as  occurring  when  other  important  secretions  are  sud- 
denly suspended. 

3. — Evolution  of  Light. 

666.  Although  the  evolution  of  Light  from  the  living  Human  subject  is  an 
exceptional  phenomenon,  which  has  only  been  observed  in  morbid  states  of  the 
body,  yet  its  occasional  occurrence  is  fraught  with  interest  to  the  Physiologist, 
on  the  one  hand  from  its  relation  to  the  Luminosity  so  common  among  the 
lower  animals,  and  on  the  other  from  the  indications  which  it  affords  of  the 
possibility  of  the  formation,  even  during  life,  of  peculiar  phosphuretted  com- 
pounds, which,  being  products  of  incipient  decomposition,  have  been  usually 
supposed  to  be  generated  only  after  death. — There  is  no  doubt  that  luminous 
exhalations  frequently  ascend  from  burial-grounds ;  and  that  the  superstitions  of 
many  nations  respecting  "  corpse-lights"  have  to  this  extent  a  foundation  in  fact. 
A  very  decided  luminosity  has  been  observed  to  proceed  from  dissecting-room 
subjects,  the  light  thus  evolved  being  sufficient  to  render  the  forms  of  the 
bodies,  as  well  as  those  of  muscles  and  other  dissected  parts  (which  are  pecu- 
liarly bright),  almost  as  distinct  as  in  the  day-light.  That  this  proceeds  from 
the  production  of  a  peculiar  phosphorescent  compound,  is  shown  by  the  fact, 
that  the  luminosity  may  be  communicated  to  the  fingers,  or  to  towels,  &c.,  by 
contact  with  the  luminous  surfaces.1 — Dr.  W.  Stokes  narrates  the  case  of  a 
patient  who  was  under  his  observation,  some  years  since,  in  the  Old  Meath 
Hospital,  having  been  admitted  on  account  of  an  enormous  cancer  in  her  breast, 
which  was  in  an  advanced  stage  of  ulceration,  the  edges  being  irregular  and 
everted ;  every  part  of  the  base  and  edges  of  this  cavity  was  strongly  phosphor- 
escent, the  light  being  sufficient  to  enable  the  figures  on  a  watch-dial  to  be  dis- 
tinguished within  a  few  inches;-  and  here  also  it  appeared  that  the  luminosity 
was  due  to  a  particular  exudation  from  the  exposed  surface.  Three  cases  are 
recorded  by  Sir  H.  Marsh,  in  which  an  evolution  of  light  took  place  from  the 
living  body,  without  any  such  obvious  source  of  decomposition ;  all  the  subjects 
of  these  cases,  however,  were  in  the  last  stage  of  phthisis;  and  it  cannot  be 
doubted  that  here,  as  in  other  diseases  of  exhaustion,  incipient  disintegration 
was  taking  place  during  the  later  periods  of  life  (§  418).  The  light  in  each 
case  is  described  as  playing  around  the  face,  but  not  as  directly  proceeding  from 
the  surface ;  and  in  one  of  these  instances,  which  was  recorded  by  Dr.  D.  Dono- 
van,2 the  luminous  appearance  was  not  only  perceptible  over  the  head  of  the 
patient's  bed,  but  luminous  vapors  passed  in  streams  through  the  apartment. 
It  can  scarcely  be  doubted  that  it  was  here  the  breath  which  contained  the 
luminous  compound,  more  especially  as  in  one  of  the  cases  it  was  observed  to 
have  a  very  peculiar  smell;  and  the  probability  that  the  luminosity  was  due  to 
the  presence  of  phosphorus  in  progress  of  slow  oxidation,  is  greatly  increased 
by  the  fact  already  referred  to  (§  570),  that  the  injection  of  phosphuretted  oil 
into  the  bloodvessels  gives  rise  to  a  similar  appearance.  In  repeating  this  ex- 
perimenta  Sir  H.  Marsh  states  that  when  half  an  ounce  of  olive  oil,  holding  two 

1  See  Sir  Herbert  Marsh  on  "The  Evolution  of  Light  from  the  Living  Human  Subject" 
(Dublin,  1842),  p.  20. — From  thia  interesting  pamphlet,  most  of  the  statements  in  this 
paragraph  are  derived. 

8  "Dublin  Medical  Press,"  Jan.  15,  1840. 


EVOLUTION    OF   ELECTRICITY.  633 

grains  of  phosphorus  in  solution,  was  injected  into  the  crural  vein  of  a  dog,  a 
dense  white  vapor  began  to  issue  from  the  nostrils  even  before  the  syringe  was 
completely  emptied,  which  became  faintly  luminous  on  the  removal  of  the 
lights:  and,  the  injection  being  repeated  with  the  same  quantity,  the  expiration 
immediately  became  beautifully  luminous,  resembling  jets  of  pale-colored  flame 
pouring  forth  from  the  nostrils  of  the^animal.  And  the  luminosity  which  has 
been  occasionally  observed  in  the  urine,1  may  fairly  be  imputed  to  an  increase 
in  the  quantity  of  unoxidized  phosphorus  which  it  seems  normally  to  contain ; 
its  liberation  taking  place  at  a  more  rapid  rate  than  its  conversion  into  phos- 
phoric acid  (§  641),  either  through  excessive  excretion  or  through  impeded  re- 
spiration. A  case  has  been  recorded  by  Kaster  (loc.  cit.)  in  which  the  body- 
linen  was  rendered  luminous  by  the  perspiration  after  any  violent  exercise; 
and  here,  too,  the  cause  may  be  presumed  to  have  been  the  same. — On  the 
whole,  then,  we  may  conclude  the  occasional  evolution  of  Light  from  the  Hu- 
man subject  to  be  the  consequence  (when  not  an  electrical  phenomenon)  of  the 
production  of  a  phosphorescent  compound  at  the  expense  of  the  disintegrating 
tissues ;  which  compound  passes  off  through  one  of  the  ordinary  channels  of 
excretion. 


4. — Evolution  of  Electricity. 

667.  "When  the  vast  variety  of  changes  of  condition  to  which  the  components 
of  the  living  body  are  subjected  during  the  performance  of  its  vital  operations, 
and  the  impossibility  of  the  occurrence  of  any  of  these  without  some  disturb- 
ance of  electric  equilibrium,9  are  duly  considered,  the  wonder  is,  not  that  such 
disturbance  should  be  occasionally  so  considerable  as  to  make  itself  apparent, 
but  that  it  should  be  ordinarily  so  obscure  as  only  to  be  detected  by  the  most 
careful  search,  and  with  the  assistance  of  the  most  delicate  instruments. — The 
researches  of  Prof.  Matteucci,  M.  du  Bois-Reymond,  and  others,  however,  have 
now  made  it  apparent,  that  there  are  no  two  parts  of  the  body  (save  those  which 
correspond  on  the  opposite  sides)  whose  electrical  condition  is  precisely  the 
same ;  and  that  the  diiferences  between  them  are  greater  in  proportion  to  the 
diversity  of  the  vital  processes  which  are  taking  place  in  them,  and  to  the 
activity  with  which  these  are  being  carried  on.  Thus,  Donne  found  that  the 
skin  and  most  of  the  internal  membranes  are  in  opposite  electrical  states;  and 
Matteucci  observed  a  considerable  deflection  of  the  needle  of  a  delicate  galvano- 
meter, when  the  liver  and  stomach  of  a  rabbit  were  connected  with  its  platinum 
electrodes.3'  More  recently,  Mr.  Baxter  has  found  that  if  one  of  the  electrodes 
be  placed  upon  any  part  of  the  intestinal  surface,  and  the  other  be  inserted  into 

1  "Casper's  Wochenschrift,"  1849,  No.  15. — A  case  has  been  recently  put  on  record 
(Biichner's  Repert.  B.  viii.  p.  342),  in  which  the  urine  and  semen  of  a  patient  who  was 
under  treatment  for  impotence  and  spermatorrhoea,  and  who  was  employing  phosphorus 
as  a  remedy  both  internally  and  externally,  were  observed  to  be  luminous. 

2  There  is  probably  no  instance  of  chemical  union  or  decomposition,  in  which  the  electric 
condition  of  the  bodies  concerned  is  not  altered.     Simple  change  of  form,  from  solid  to 
liquid,  or  from  liquid  to  gaseous,  is  attended  with  electric  disturbance ;  and  this  is  greatly 
increased  when  any  separation  takes  place  between  substances  that  were  previously  united, 
as  when  water  containing  a  small  quantity  of  saline  matter  is  caused  to  evaporate  and  to 
leave  it  behind.     Heat,  again,  is  continually  generating  Electricity ;  for  not  only  is  a  cur- 
rent produced  by  the  heating  of  two  dissimilar  metals  in  contact,  but  also  by  the  unequal 
heating  of  two  parts  of  the  same  bar ;  and  though  the  effect  is  most  striking  in  the  case 
of  metals,  it  is  by  no  means  limited  to  them.     And  so  constantly  is  Electricity  generated 
by  the  retardation  of  motion,  as  in  friction,  that  it  is  not  possible  to  rub  together  any  two 
substances,  excepting  such  as  are  of  the  most  perfect  homogeneity  (such  as  the  fractured 
surfaces  of  a  broken  bar)  without  the  production  of  electric  change,  as  well  as  of  heat. 

3  See  M.  Becquerel's  "  Traite  de  I'Electricite,"  torn.  i.  p.  327,  and  torn.  iv.  p.  300. 


634  EVOLUTION   OP   HEAT,    LIGHT,    AND   ELECTRICITY. 

the  branch  of  the  mesenteric  vein  proceeding  from  it,  a  decided  deflection  of 
the  needle  was  produced,  indicating  a  positive  condition  of  the  blood;  but  that 
no  effect  was  produced  when  the  second  electrode  was  inserted  into  the  artery 
of  the  part  instead  of  into  its  vein.  These  effects  were  found  to  cease  after  the 
death  of  the  animals ;  and  could  not  be  attributed,  therefore,  to  mere  chemical 
differences  between  the  blood  and  the  secreted  product ;  but  must  have  arisen 
from  electric  disturbance  taking  place  in' the  very  act  of  secretion.1 — That  the 
process  of  Nutrition,  as  well  as  of  Secretion,  in  parts  which  are  undergoing 
rapid  molecular  change,  gives  rise  to  electric  disturbance,  is  proved  by  the  ex- 
periments of  Matteucci  and  Du  Bois-Reymond  upon  the  relative  electrical  states 
of  different  parts  of  muscles  and  nerves.  If  the  two  extremities  of  a  muscle, 
removed  from  the  body  of  an  animal  very  recently  killed,  be  applied  to  the  two 
electrodes  of  a  delicate  galvanometer,  there  is  usually  some  deflection  of  the 
needle;  this  being  greater  in  proportion  to  the  difference  in  the  arrangement  of 
the  muscular  and  tendinous  elements  of  the  two  extremities.  Although  the 
direction  of  the  current  is  constant  for  each  muscle,  yet  there  is  no  constant 
relation  between  the  direction  of  the  currents  and  the  position  of  the  muscles  in 
the  body;  thus,  in  the  gastrocnemius  of  the  Frog's  leg,  the  direction  is  from 
the  foot  towards  the  body,  whilst  in  the  sartorius  it  is  the  reverse.  Taking  all 
the  muscles  of  a  part  together,  however,  there  is  usually  such  a  want  of  balance 
between  the  opposite  currents,  that  a  constant  current  is  established  in  the 
direction  of  the  strongest  and  -most  numerous  of  the  separate  muscular  currents ; 
this,  in  the  Frog,  passes  uniformly  from  the  hind-feet  towards  the  head,  and 
was  at  one  time  supposed  to  be  peculiar  to  that  animal ;  but  a  similar  current 
may  almost  always  be  detected  in  other  animals.  The  muscular  current  grows 
feebler  and  feebler,  the  longer  the  muscle  has  been  removed  from  the  body ;  it 
is  affected  by  any  agents  which  tend  to  lower  its  vitality,  and  becomes  extinct 
as  soon  as  its  contractility  ceases.  From  the  experiments  of  M.  du  Bois-Rey- 
mond, to  be  presently  described  (§  670),  it  may  be  concluded  that  the  current 
in  the  arm  of  Man,  when  at  rest,  is  from  the  shoulder  towards  the  points  of  the 
fingers. 

668.  The  conditions  of  the  "  muscular  current"  have  been  made  the  subject 
of  special  investigation  by  M.  du  Bois-Reymond ;  and  the  following  is  an  out- 
line of  the  results  at  which  he  has  arrived,  for  whose  due  comprehension,  how- 
ever, it  is  requisite  that  the  terms  employed  by  him  should  be  first  defined. — 
The  entire  muscle  being  composed  of  a  mass  of  fibres,  having  a  generally  parallel 
direction,  and  attached  at  their  extremities  to  tendinous  structure,  which  has  in 
itself  but  little  or  no  electro-motor  power,  but  is  a  conductor  of  electricity,  it 
follows  that  the  tendon  or  tendinous  portion  of  a  muscle  represents  a  surface 
formed  by  the  bases  of  the  muscular  fibres  considered  as  prisms,  which  may  be 
designated  its  natural  transverse  section.  On  the  other  hand,  the  fleshy  surface 
of  the  muscle,  which  is  formed  only  by  the  sides  of  the  fibres  considered  as 
prisms,  may  be  regarded  as  the  natural  longitudinal  section  of  the  muscle. 
Again,  if  a  muscle  be  divided  in  a  direction  more  or  less  perpendicular  to  its 
fibres,  an  artificial  transverse  section  will  be  made ;  whilst  if  the  muscle  be  torn 
lengthways  in  the  direction  of  its  fibres,  an  artificial  longitudinal  section  will 
be  made ;  and  these  artificial  sections  show  the  same  electric  conditions  with 
their  corresponding  natural  sections.  Now  experiments  repeated  in  a  great 
variety  of  modes  demonstrate  that  every  point  in  the  natural  or  artificial  longi- 
tudinal section  of  a  muscle  is  positive  in  relation  to  every  part  of  its  transverse 
section,  whether  natural  or  artificial;  the  most  powerful  influence  on  the  gal- 
vanometer being  produced,  when  a  portion  of  the  surface  (or  natural  longitudinal 
section)  of  a  muscle  is  laid  upon  one  of  the  electrodes,  and  a  portion  of  the 

1  "Philosophical  Transactions,"  1848,  p.  248. 


EVOLUTION    OF  ELECTRICITY. 


635 


surface  formed  by  cutting  the  muscle  across  (or  artificial  transverse  section)  is 
placed  against  the  other.  When  the  two  tendinous  extremities  of  a  muscle, 
whose  form  is  symmetrical  or  nearly  so,  are  placed  against  the  electrodes,  the 
deflection  of  the  needle  of  the  galvanometer  is  but  slight;  and  the  same  is  the 
case  with  two  transverse  sections  taken  at  equal  distances  from  the  two  ends  of 
the  muscle,  and  also  with  two  points  of  the  longitudinal  section  which  are  equally 
distant  from  the  middle  of  its  length.  But  if  the  two  points  of  the  longitudinal 
section  applied  to  the  electrodes  be  not  equally  distant  from  the  centre  of  the 
muscle,  then  the  point  which  is  nearest  to  the  centre  is  positive  to  the  one 
which  is  nearest  to  the  end ;  and,  in  like  manner,  when  the  different  parts  of 
the  transverse  section  are  tested  in  regard  to  each  other,  the  points  lying  nearest 
the  surface  of  the  muscle  are  found  to  be  positive  to  those  nearer  its  interior. 
The  intensity  of  the  current,  however,  between  any  two  points  in  the  same 
section — whether  transverse  or  longitudinal — is  always  incomparably  less  than 
that  of  the  currents  which  are  obtained  between  two  points  in  different  sections, 
one  in  the  longitudinal  and  the  other  in  the  transverse.  These  results  may  be 
obtained,  not  merely  with  the  entire  muscle,  but  with  insulated  portions  of  it ; 
and  even,  as  we  are  assured  by  M.  du  Bois-Reymond,  with  a  single  primitive 
fasciculus.  Hence  it.  seems  unquestionable  that  every  integral  particle  of  the 
muscular  substance  must  be  a  centre  of  electro-motor  action,  and  must  contain 
within  itself  positive  and  negative  elements ;  and  the  variations  both  of  intens- 
ity and  direction  in  the  muscular  current,  under  certain  circumstances,  are  so 
sudden  and  so  extensive,  that  it  appears  impossible  to  account  for  them  by  any 
change  of  larger  heterogeneous  elements,  or  in  any  other  way  than  by  assuming 
corresponding  changes  of  position  in  almost  infinitely  small  centres  of  action. 
It  is  indifferent  what  form  is  assigned  to  these  electromotive  molecules ;  but  it 
would  seem  that  they  must  have  two  negative  polar  zones,  and  a  positive  equa- 
torial zone ;  a  combination  of  such  elements  being  able  to  produce  all  the  elec- 
trical effects  of  a  muscle  in  a  state  of  rest.  It  seems  altogether  best  to  suit  the 
phenomena,  to  suppose  that  each  of  these  peripolar  molecules  is  formed  by  the 
combination  of  two  dipolar  molecules,  touching  each  other  by  their  positive 
poles — as  in  the  subjoined  table,  which  represents  a  band  of  four  series,  A,  B,  C, 
D,  each  series  containing  four  dipolar  molecules. 


{t 
g 
@ 


4- 

4- 

1? 

4- 

+ 

4-j  2 

-f 

4- 

!}• 

+ 

i 

t}« 

B 

C 

D 

669.  The  current  shown  by  the  entire  muscle,  when  made  to  form  part  of  a 
circuit,  is  only  a  derived  current  produced  by  incomparably  more  intense  currents 
circulating  in  the  interior  of  the  muscle  around  these  ultimate  particles,  and 
will  vary  greatly  in  intensity,  according  to  the  mode  in  which  these  particles 
are  arranged ;  generally  speaking,  however,  it  increases  both  with  the  length 
and  with  the  thickness  of  the  muscle.  There  is,  however,  another  cause  of  a 


636  EVOLUTION   OF   HEAT,    LIGHT,    AND    ELECTRICITY. 

very  remarkable  nature,  which  influences  both  its  intensity  and  its  direction ; 
this,  according  to  M.  du  Bois-Reymond,  is  the  existence  of  a  thin  layer  of 
muscular  substance,  beneath  the  tendinous  expansion,  whose  electromotive  power 
is  exactly  opposite  to  that  of  the  rest,  so  that  its  action  tends  to  reverse  the 
general  law  of  the  muscular  current.  For  when  the  gastrocnemius  of  a  frog  is 
placed  between  the  two  electrodes,  so  as  to  touch  them  only  with  its  tendinous 
extremities,  it  gives  a  weak  upward  current;  but  if  the  frog  have  been  previously 
cooled,  there  will  probably  be  no  current  at  all;  or  if  it  have  been  frozen,  there 
may  actually  be  a  current  in  the  opposite  direction.  If,  now,  a  drop  of  any 
liquid  capable  of  corroding  the  muscular  tissue  (such  as  alcohol,  creosote,  acids, 
alkaline  solutions,  &c.),  be  placed  upon  the  aponeurosis-  of  the  tendo-Achillis, 
the  ordinary  upward  current  of  the  muscle  is  evolved ;  and  the  same  effect  is 
produced  by  completely  removing  a  thin  layer  of  muscular  substance  at  the 
natural  transverse  section.  This  effect  is  accounted  for  by  M.  du  Bois-Reymond, 
on  the  supposition  that,  at  the  tendinous  extremities  of  the  muscular  fibres,  the 
linear  series  of  peripolar  elements  is  terminated  by  a  single  dipolar  element, 
whose  positive  pole  is  thus  free,  instead  of  the  negative  pole  being  so ;  and  he 
has  shown  that  by  an  apparatus  of  zinc  and  copper,  constructed  after  this  plan, 
all  the  electric  phenomena  of  the  muscle  at  rest  may  be  imitated. 

670.  That  a  change  in  the  electric  state  of  a  muscle  takes  place  in  the  act  of 
contraction,  had  been  ascertained  by  the  experiments  of  Prof.  Matteucci  (§  330); 
but,  as  he  was  only  able  to  detect  this  by  the  galvanoscopic  frog  (the  galvano- 
meter which  he  employed  not  giving  unquestionable  indications  of  it),  he  was 
not  able  to  determine  its  nature  with  accuracy.  This  has  been  accomplished, 
however,  by  M.  du  Bois-Reymond,  who  has  shown  that  during  contraction  the 
muscular  current  is  not  increased  (as  supposed  by  Matteucci),  but  is  diminished 
and  even  reduced  to  zero.  In  order  to  exhibit  this  phenomenon  satisfactorily, 
it  is  found  advantageous  to  cause  the  muscle  to  contract  powerfully  or  unin- 
terruptedly for  as  long  a  time  as  possible,  that  is,  to  tetanize  it ;  and  this  may 
be  effected  by  acting  violently  on  its  nerve  by  heat,  chemical  agents,  or  a 
succession  of  electric  shocks ;  or  by  poisoning  the  animal  with  strychnia.  In 
whatever  mode  the  tetanized  state  is  induced,  the  same  result  follows ; — the 
needle  of  the  galvanometer  passes  over  to  the  negative  side.  This,  however, 
does  not  indicate  (as  might  be  at  first  supposed)  the  development  of  a  new  current 
during  the  contraction,  in  a  direction  opposite  to  that  which  prevails  during  rest; 
but  it  is  the  consequence  of  the  "  secondary  polarity''1  which  is  evolved  in  the 
platinum  electrodes,  as  soon  as  the  muscular  current  is  diminished ;  the  needle 
passing  from  the  positive  to  the  negative  side,  as  soon  as  the  current  of  the 
secondary  polarity  becomes  more  powerful  than  the  original  muscular  current. 
This  negative  deflection  of  the  needle  at  the  moment  of  contraction  is  always 
proportional  to  the  actual  intensity  of  the  current  of  the  muscle  while  at  rest ; 
and  it  ceases  as  soon  as  the  tetanic  contraction  ceases,  after  which  the  muscular 
current  gradually  recovers  its  previous  intensity. — Thus,  then,  it  appears  that 
the  contraction  of  a  muscle  is  attended  with  a  marked  diminution  of  its 

1  When  the  electromotor  body  is  removed,  and  the  two  electrodes  (platinum  plates 
immersed  in  a  saturated  solution  of  common  salt)  are  connected  by  some  imperfectly 
conducting  body,  a  secondary  current  is  manifested  in  the  reverse  direction  to  the  first, 
the  needle  being  deflected  to  the  other  side;  this  is  caused  by  the  electro-chemical  reaction 
of  the  substances  which  the  current  of  animal  electricity  has  evolved  on  the  platinum 
plates  by  means  of  its  electrolytic  action ;  and  its  occurrence  is  often  a  useful  and  valuable 
confirmation  of  the  first  result,  as  showing  that  the  primary  deflection  really  was  the 
consequence  of  the  presence  of  an  electromotor.  When  the  electromotive  action,  moreover, 
is  very  weak,  it  may  be  made  more  evident  by  reversing  the  position  of  the  electromotor, 
without  first  replacing  the  connecter ;  so  that  the  action  which  it  will  then  exert  in  the 
reverse  direction  will  be  strengthened  by  the  secondary  current  developed  by  the  previous 
action. 


EVOLUTION   OF   ELECTRICITY.  637 

electromotive  power ;  a  fact  which  seems  to  harmonize  well  with  the  general 
views  formerly  adverted  to  in  regard  to  -the  "correlation  of  forces;"  the  changes 
which  operate  to  produce  disturbance  of  electric  equilibrium  whilst  the  muscle 
is  at  rest,  being  concerned  in  the  development  of  motor  power  when  it  is  thrown 
into  contraction.  This  alteration  has  been  demonstrated  by  M.  du  Bois-Reymond 
in  the  living  animal,  after  the  following  manner.  The  two  feet  of  a  live  frog 
were  immersed  in  the  two  connecting  vessels,  but  one  of  the  legs  was  paralyzed 
by  division  of  its  sciatic  plexus;  the  muscular  currents  of  the  muscles  of  the 
two  limbs  neutralized  each  other,  so  long  as  they  remained  at  rest ;  but  upon 
the  frog  being  poisoned  with  strychnia,  so  that  tetanic  convulsions  occurred  in 
one  limb  whilst  the  other  remained  motionless,  the  current  in  the  former  limb 
was  weakened,  whilst  that  of  the  other  remained  unaffected,  and  a  deflection  of 
the  needle  took  place,  indicating  an  upward  current  in  the  paralyzed  limb  and 
a  downward  current  in  the  tetanized  one.  The  same  thing  may  be  shown  in 
the  Human  subject,  by  dipping  the  forefingers  of  the  two  hands  into  the  two 
conducting  vessels  connected  with  the  galvanometer,  so  that  the  two  arms  are 
included  in  opposite  directions  in  the  circuit ;  when  if,  after  the  needle  (which 
usually  undergoes  a  temporary  disturbance  on  their  first  immersion)  has  come 
to  a  state  of  rest,  all  the  muscles  of  one  of  the  arms  be  strongly  and  permanently 
contracted,  so  as  to  give  them  the  greatest  possible  tension  without  changing 
the  position  of  the  arm,  the  needle  is  instantly  deflected,  always  indicating  a 
current  from  the  hand  to  the  shoulder,  that  is,  an  upward  current  in  the  con- 
tracted arm.  Hence,  according  to  the  explanation  just  given,  the  contracted 
arm  plays  the  part  of  the  negative  metal  in  the  circuit,  in  regard  to  the  arm 
whose  muscles  remain  in  the  state  of  relaxation,  showing  that  the  normal  current 
will  be  a  downward  one. — This  change,  however,  is  so  extremely  slight,  that  a 
very  delicate  galvanometer  is  requisite  to  render  it  perceptible.  Its  intensity 
depends  very  much  on  the  muscular  energy  of  the  experimenter ;  and  even  the 
greater  power  which  the  right  arm  usually  possesses  becomes  perceptible  in  the 
greater  deflection  of  the  needle  when  it  is  put  in  action.1 

671.  The  discovery  that  an  electric  current  exists  in  nerves,  the  conditions  of 
which  are  in  most  respects  similar  to  that  of  thfe  Muscular  current,  is  entirely 
due  to  M.  du  Bois-Reymond.  When  a  small  piece  of  a  nerve-trunk  is  cut  out 
from  the  recently  killed  body,  and  is  so  placed  upon  the  electrodes  that  it  touches 
one  of  them  with  its  surface  (or  natural  longitudinal  section),  and  the  other 
with  its  cut  extremity  (or  artificial  transverse  section),  a  considerable  deflection 
of  the  index  is  produced,  the  direction  of  which  always  indicates  the  passage  of 
a  current  from  the  interior  to  the  exterior  of  the  nerve-trunk.  It  is  indifferent 
in  regard  to  the  direction  of  the  current,  whether  the  central  or  the  peripheral 
cut  extremity  be  applied  to  the  electrode ;  and  in  fact  the  most  powerful  effect 
is  obtained  by  doubling  the  nerve  in  the  middle,  and  applying  both  transverse 
sections  to  one  electrode,  whilst  the  loop  is  applied  to  the  other.  On  the  other 
hand,  if  the  two  cut  extremities  be  applied  to  the  two  electrodes  respectively,  no 
decided  effect  is  produced ;  and  the  same  neutrality  exists  between  any  two 
points  of  the  surface  of  the  trunk,  equidistant  from  the  middle  of  its  length  ; 

1  Of  this  very  remarkable  experiment,  which  was  first  made  by  M.  du  Bois-Reymond, 
the  Author  has  himself  (through  that  gentleman's  kindness)  been  a  witness;  and  he  gladly 
bears  his  testimony  to  its  highly  satisfactory  character,  and  withdraws  the  doubt  previously 
expressed  (on  the  authority  of  Prof.  Matteucci's  negative  statements)  in  regard  to  the 
reality  of  this  phenomenon  ($  330,  note). — The  success  of  M.  du  Bois-Reymond  in  these 
and  similar  investigations,  is  doubtless  due  in  great  part  to  the  marvellous  sensitiveness 
of  the  galvanometer  he  employs,  the  coils  of  which  consist  of  three  miles  of  wire,  as  well 
as  to  the  perfection  of  the  various  arrangements  by  which  he  is  enabled  to  avoid  or 
eliminate  sources  of  error;  but  it  must  be  attributed  in  great  part  also  to  the  philosophic 
method  on  which  his  inquiries  are  planned,  and  to  the  skill  and  perseverance  with  which 
they  are  carried  out. 


638  EVOLUTION   OF   HEAT,    LIGHT,    AND   ELECTRICITY. 

but  if  the  points  be  not  equidistant,  then  a  slight  deflection  is  produced,  indicat- 
ing that  the  parts  nearer  the  middle  are  positive  to  those  nearer  the  extremities. 
It  has  not  been  found  possible,  owing  to  the  small  size  of  the  nerve-trunks  ex- 
perimented on,  to  test  in  a  similar  manner  the  relative  state  of  different  points 
of  their  transverse  section  ;  but  there  can  be  little  doubt,  from  the  complete  con- 
formity which  exists  in  other  respects  between  the  nervous  and  muscular  cur- 
rents, that  the  same  law  will  be  found  to  prevail  in  this  as  in  the  former  case ; 
namely,  that  the  points  nearer  the  surface  are  positive  to  those  nearer  the  centre. 
There  is  no  difference  between  the  motor  and  the  sensory  nerves  in  regard  to 
the  direction  of  this  current,  the  existence  of  which  has  been  proved  by  M.  du 
Bois-Reymond,  not  only  by  the  galvanometer,  but  also  by  the  excitement  of 
contractions  in  the  limb  of  the  galvanoscopic  frog. — The  "nervous  current/' 
like  the  muscular,  must  be  considered  as  derived  from  the  electromotive  action 
of  the  molecules  of  the  nerve ;  and,  for  the  reasons  already  pointed  out,  the 
intensity  of  the  current  in  the  immediate  neighborhood  of  the  molecules  may 
be  infinitely  greater 'than  that  which  is  shown  by  the  galvanometer  to  exist  in 
the  trunk  of  the  nerve. 

672.  We  have  now  to  follow  M.  du  Bois-Reymond  through  his  investigations 
on  the  change  in  the  condition  of  the  "  nervous  current/'  whilst  the  nerve  is  in 
a  state  of  functional  activity,  whether  motorial  or  sensorial.  For  the  examina- 
tion of  this,  it  is  desirable  to  induce  a  state  of  continuous  action  in  the  nerve, 
analogous  to  the  tetanic  contraction  of  muscle ;  and  this  condition  in  the  motor 
nerve  is  manifestly  that  which  induces  tetanus  in  its  muscle ;  whilst  in  sensory 
nerves  it  is  that  in  which  a  violent  sensation  is  uninterruptedly  kept  up.  No 
means  of  exciting  such  a  state  are  so  certain  and  simple  as  electric  currents ; 
but  it  is  necessary  in  the  first  place  to  determine  the  modification  which  these 
currents  may  themselves  produce  in  the  proper  "  nerv- 
ous current."  If  a  portion  of  nerve-trunk  be  so 
placed  (Fig.  173),  that  it  touches  one  of  the  electrodes 
by  its  transverse  section  (which  may  be  designated  T), 
and  the  other  by  its  surface  or  longitudinal  section 
(L),  and  a  portion  of  its  continuation  be  included  in 
a  galvanic  circuit,  so  that  a  current  shall  pass  in  the 
direction  zS9-»p?  which  is  the  same  in  its  direction  as 
that  between  T^->L,  then  the  intensity  of  the  "nervous 
current"  T^->L,  as  indicated  by  the  deflection  of 
the  needle  of  the  galvanometer,  will  be  found  to  under- 
go an  increase ;  whilst  on  the  other  hand,  if  the  electric 
current  be  passed  in  the  contrary  direction  p^-*z,  the 
intensity  of  the  "  nervous  current"  T^-^L  will  de- 
crease.— The  portion  z^-*r  of  the  nerve,  which  is 
included  in  the  electric  circuit,  is  termed  the  excited 
portion,  and  the  current  passed  through  it  is  the  excit- 
ing current ;  on  the  other  hand,  the  portion  T^-*L  in- 
cluded between  the  electrodes  of  the  galvanometer  is  the  derived  portion ;  and 
the  altered  condition  of  this  part,  which  is  produced  by  the  extraneous  current 
(this  current  having  been  experimentally  proved  by  M.  du  Bois-Reymond  to 
exert  no  direct  influence  on  the  galvanometer),  is  termed  the  electrotonic  state 
of  the  nerve.  When  the  intensity  of  the  "nervous  current"  is  increased,  the 
nerve  is  said  to  be  in  the  positive  phase  of  this  electrotonic  state ;  and  when  it  is 
diminished,  the  nerve  is  in  the  negative  phase  of  that  state. — By  a  proper 
arrangement,  the  same  exciting  current  may  be  made  to  produce  the  positive 
phase  in  one  part  of  a  nerve-trunk,  and  the  negative  phase  in  another.  Thus  if 
the  two  extremities  of  a  nerve  (Fig.  170,  p  and  c)  be  so  connected  with  two 
galvanometers,  that  both  shall  develope  the  "nervous  current,"  and  an  inter- 


EVOLUTION   OF   ELECTRICITY.  639 

mediate  portion  be  excited  by  the  transmission  of  an  electric  current  in  the 
direction  z^-*P,  the  nervous  current  in  the  "  derived"  portion  c  will  be  in- 
creased in  intensity,  whilst  that  in  the  por- 
tion^) will  be  diminished. — Hence  it  may  FiS-  170. 
be  inferred  that  when  any  portion  of  the 
length  of  a  nerve  is  traversed  by  an  electric 
current,  besides  the  usual  electromotive 
action  of  the  nerve,  a  new  electromotive 
action  takes  place  in  every  point  of  the 
nerve,  by  a  polarization  of  its  electromotive 
elements,  which  action  has  the  same  direc- 
tion as  the  exciting  current  itself;  and  a 
current  is  thus  produced  in  the  "derived" 
portion  which  is  added  to  the  original 
"nervous  current"  at  that  end  of  the  nerve 
at  which  the  direction  of  this  new  current 
and  of  the  nervous  current  coincide,  and 
is  subtracted  at  that  end  at  which  the 
directions  are  different.  These  variations 

in  the  intensity  of  the  "nervous  current"  continue  as  long  as  the  "exciting 
current"  lasts,  and  immediately  cease  when  the  circuit  of  that  current  is 
broken.  It  is  to  the  induction  of  the  electrotonic  state  in  the  nerve  sup- 
plying it  that  the  contraction  of  a  muscle  is  due,  which  ensues  on  the  com- 
pletion of  the  circuit;  and  to  the  cessation  of  this  state,  that  the  muscular 
contraction  is  due  which  is  consequent  upon  the  interruption  of  the  circuit. 
Hence  the  electrotonic  changes  in  the  condition  of  nerves  may  be  observed 
without  previously  dividing  them. — When,  on  the  other  hand,  a  nerve  is 
"tetanized"  by  passing  an  interrupted  and  alternating  current  through  a  portion 
of  it,  the  effect  is,  as  in  the  case  of  muscle,  to  produce  a  diminution  in  its  own 
proper  current;  the  needles  of  both  galvanometers,  in  the  arrangement  last  de- 
scribed, being  deflected  to  the  negative  side,  instead  of  one  going  back  to  zero, 
and  the  positive  deflection  of  the  other  being  increased,  as  happens  when  the 
"excited  portion"  is  subjected  to  a  continuous  and  uniform  current.  The  same 
negative  variation  of  the  nervous  current  has  been  demonstrated  by  M.  du  Bois- 
Reymond  in  nerves  tetanized  by  other  means,  as  by  the  use  of  strychnia.  And 
the  phenomena  both  of  the  "  electrotonic  state,"  and  of  the  "negative  variation" 
are  precisely  the  same,  whether  motor  or  sensory  nerves  be  subjected  to  the 
experiment ;  thus  making  it  appear  that  nerve-force  may  be  transmitted  in  either 
direction  along  each  of  these  orders  of  nerves. — A  very  remarkable  modification 
of  the  "nervous  current"  has  been  shown  by  M.  du  Bois-Reyinond  to  follow 
severe  injuries  of  the  nerve,  by  mechanical,  chemical,  or  thermal  agencies.  If, 
for  instance,  a  piece  of  hot  metal  be  brought  near  to  the  nerve  without  touching 
it,  the  nervous  current  will  be  seen  to  sink  rapidly,  and  to  have  its  direction 
reversed,  during  which  the  property  possessed  by  the  nerve  of  conveying  irrita- 
tion to  the  muscle,  though  somewhat  impaired,  will  not  be  destroyed ;  and  if, 
whilst  in  this  abnormal  state,  the  nerve  be  divided,  every  transverse  section  is 
found  neutral  or  positive  to  the  longitudinal  section,  instead  of  negative.  If 
the  nerve-trunk  be  then  placed  between  muscles,  so  as  to  recover  its  natural 
moisture,  it  will  at  the  same  time  recover  its  usual  electromotive  power.1 

1  The  materials^of  the  five  preceding  paragraphs  have  been  derived  from  the  sketch  of 
M.  du  Bois-Reymond's  researches,  which  has  been  recently  published  by  Dr.  Bence  Jones 
( "  On  Animal  Electricity :  being  an  Abstract  of  the  Discoveries  of  Emil  du  Bois-Reymond" ). 
Having  himself  had  the  opportunity  of  witnessing  a  considerable  number  of  the  experiments 
above  referred  to,  the  Author  feels  it  due  to  M.  du  Bois-Reymond  to  state,  that  their  results 
correspond  so  precisely  with  his  predictions  in  every  instance,  as  to  prove  that  lie  had  ac- 


640  EVOLUTION   OF    HEAT,    LIGHT,    AND   ELECTRICITY. 

673.  Some  of  the  most  important  parts  of  the  body  being  thus  in  a  state  of 
constant  disequilibrium  with  regard  to  each  other,  it  is  not  surprising  that  the 
electric  state  of  the  whole  should  be  ordinarily  in  disequilibrium  with  that  of 
surrounding  bodies.  This  difference,  however,  is  usually  prevented  from  mani- 
festing itself,  in  consequence  of  the  restoration  of  the  equilibrium  by  the  free 
contact  which  is  continually  taking  place  between  them ;  and  it  is  for  the  most 
part  only  when  the  Human  body  is  insulated,  that  it  becomes  apparent.  The 
galvanometer  is  then  affected,  however,  by  the  contact  of  one  of  its  electrodes 
with  the  person  insulated,  and  the  other  with  any  neighboring  uninsulated  body ; 
and  also  by  the  contact  of  the  electrode  with  the  hands  of  two  persons  both  in- 
sulated, who  join  their  other  hands  together,  a  difference  in  the  electrical  states  of 
the  two  individuals  being  thus  indicated.  The  electricity  of  man  is  most  frequently 
positive,  and  irritable  men  of  sanguine  temperament  have  more  free  electricity 
than  those  of  phlegmatic  character;  the  electricity  of  women  is  more  frequently 
negative  than  that  of  men.  There  are  persons  who  scarcely  ever  pull  off  articles 
of  dress  which  have  'been  worn  next  the  skin,  without  sparks  and  a  crackling 
noise  being  produced;  especially  in  dry  weather,  when  the  electricity  of  the 
body  is  retained,  instead  of  being  rapidly  dissipated  as  it  is  by  a  damp  atmo- 
sphere. The  effect  is  usually  heightened,  if  silk  stockings  and  other  silken 
articles  have  been  worn,  since  these  act  as  insulators.  It  is  doubtless  in  part 
attributable  to  the  friction  of  the  articles  of  dress  against  each  other  and  against 
the  body;  but  we  can  scarcely  doubt  that  it  is  partly  due  to  the  generation  of 
electricity  in  the  body  itself,  since  it  bears  no  constant  relation  to  the  former 
of  these  supposed  causes.  Thus  a  Capuchin  friar  is  mentioned  by  Dr.  Schnei- 
der,1 who,  on  removing  his  cowl,  always  found  a  number  of  shining  crackling 
sparks  to  pass  from  his  scalp ;  and  this  phenomenon  continued  still  perceptible 
after  a  three  weeks'  illness.  The  most  remarkable  case  of  the  generation  of 
Electricity  in  the  Human  subject  at  present  known,  was  recorded  some  years 
since  in  America.3  The  subject  of  it,  a  lady,  was  for  many  months  in  an  elec- 
tric state  so  different  from  that  of  surrounding  bodies,  that,  whenever  she  was 
but  slightly  insulated  by  a  carpet  or  other  feebly  conducting  medium,  sparks 
passed  between  her  person  and  any  object  she  approached;  when  most  favorably 
circumstanced,  four  sparks  per  minute  would  pass  from  her  finger  to  the  brass 
ball  of  the  stove  at  the  distance  of  1^  inch.  From  the  pain  which  accompa- 
nied the  passage  of  the  sparks,  her  condition  was  a  source  of  much  discomfort 
to  her.  The  circumstances  which  appeared  most  favorable  to  the  generation  of 
the  electricity  were  an  atmosphere  of  about  80°,  tranquillity  of  mind,  and 
social  enjoyment;  whilst  a  low  temperature  and  depressing  emotions  diminished 
it  in  a  corresponding  degree.  The  phenomenon  was  first  noticed  during  the 
occurrence  of  an  Aurora  Borealis;  and  though  its  first  appearance  was  sudden, 
its  departure  was  gradual.  Various  experiments  were  made,  with  the  view  of 
ascertaining  if  the  electricity  was  generated  by  the  friction  of  articles  of  dress; 
but  no  change  in  these  seemed  to  modify  its  intensity. 

quired  a  thorough  mastery  over  the  conditions  of  the  phenomena.  And  he  may  mention 
the  experimental  demonstration  of  the  "nervous  current,"  as  most  fully  satisfactory. — It 
may  be  stated  with  confidence,  that  the  course  of  investigation  which  is  being  followed  out 
by  M.  du  Bois-Reymond,  is  one  pre-eminently  calculated  to  develop  results  of  importance 
in  Physiology :  and  is  the  only  one  out  of  which  definite  indications  in  regard  to  the 
Therapeutic  applications  of  Electricity  can  be  expected  to  arise. 

1  "  Casper's  Wochenschrift,"  1849,  No.  15. 

2  "American  Journal  of  Medical  Sciences,"  January,  1838. 


GENERAL   SUMMARY.  641 


CHAPTER  XIV. 

OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

1. —  General  Summary. 

674.  THE  Nervous  System  of  Man,  as  of  Vertebrated  animals  generally,  con- 
sists of  an  aggregation  of  separate  ganglionic  centres,  which  are  more  or  less 
intimately  connected  with  each  other  by  commissural  fibres,  and  which  are  called 
into  consentaneous  activity  in  a  large  proportion  of  the  operations  of  which  this 
apparatus  is  the  instrument.  Hence,  notwithstanding  the  abundant  evidence 
that  these  several  centres  differ  in  their  respective  endowments,  there  is  con- 
siderable dimculty  in  the  determination  of  their  special  functions ;  since  the 
destruction  or  removal  of  any  one  portion  of  the  Nervous  system  not  only  puts 
a  stop  to  the  phenomena  to  which  it  is  itself  directly  subservient,  but  so  de- 
ranges the  general  train  of  nervous  activity,  that  it  often  becomes  impossible  to 
ascertain,  by  any  such  method,  what  is  its  real  share  in  the  entire  performance. 
In  this  difficulty,  however,  we  may  advantageously  have  recourse  to  the  study 
of  the  structure  and  actions  of  those  forms  of  the  Nervous  system  presented  to 
us  among  the  lower  animals,  in  which  its  ganglionic  centres  are  fewer  and  less 
intimately  connected,  and  in  which,  therefore,  it  is  more  easy  to  gain  an  ac- 
quaintance with  their  several  endowments.  And  from  an  extensive  survey  of 
these,  we  seem  able  to  deduce  the  following  conclusions,  which  afford  the  most 
valuable  guidance  in  the  study  of  the  Nervous  System  of  Man.1 

I.  The  Nervous  System,  in  its  lowest  and  simplest  form,  may  consist  of  but 
a  single  ganglionic  centre,2  with  afferent  and  motor  nerves  (§  350),  whose  func- 
tion is  essentially  internuncial ;  impressions  made  upon  the  afferent  fibres  excit- 
ing respondent  movements  in  the  muscles  supplied  by  the  motor,  without  any 
necessary  intervention  of  consciousness.  Such  movements  are  properly  distin- 
guished as  excito-motor. 

n.  A  repetition  of  such  ganglionic  centres  may  exist  to  any  extent,  without 
heterogeneousness  of  function,  or  any  essential  departure  from  the  simple  mode 
of  action  just  indicated ;  each  of  these  centres  may  be  specially  connected  by 
afferent  and  motor  fibres  with  one  segment  or  division  of  the  body,  and  may 
minister  peculiarly  to  its  actions;  but  the  several  centres  may  be  so  intimately 
connected  by  commissural  fibres,  that  an  impression  made  upon  the  afferent 
nerves  of  any  one  of  them  may  excite  respondent  motions  in  other  segments.  This 
we  see  effected  through  the  annular  gangliated  cord  of  the  higher  Radiata,  and 
through  the  longitudinal  gangliated  cord  of  the  Articulata;  the  disposition  of 
the  ganglia  and  of  their  connecting  cords  having  reference  simply  to  the  general 
plan  of  the  body. 

in.  A  higher  form  of  Nervous  System  is  that  in  which  the  multiplication  of 

1  For  a  general  view  of  the  facts  on  which  these  conclusions  are  based,  see  "Princ.  of 
Phys.,  Gen.  and  Comp.,"  CHAP,  xx.,  Am.  Ed. 

2  It  may,  perhaps,  be  doubted  whether  any  Animal  really  exists,  possessing  such  nervous 
system,  and  yet  not  endowed  with  consciousness.    It  is  quite  certain,  however,  that  animals 
do  exist  (the  Tunicated  Mollusca,  for  example),  in  which  the  actions  above  referred  to  are 
the  only  ones  of  which  we  have  any  distinct  evidence  from  observation  of  their  habits. 

41 


642  OF  THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

ganglionic  centres  has  reference,  not  to  the  multiplication  of  similar  parts  which 
are  to  be  alike  supplied  with  nervous  power,  but  to  the  exercise  of  adversity  of 
functions,  through  the  instrumentality  of  different  structures ;  thus,  in  the 
higher  Articulated  and  Molluscous  tribes,  we  find  ganglionic  centres  specially 
set  apart  for  the  actions  of  deglutition  and  respiration,  as  well  as  for  those  of 
locomotion ;  but  the  modus  operandi  is  still  the  same,  these  actions  being  all 
" excito-motor,"  that  is,  being  performed  through  the  "reflex"  agency  of  their 
several  ganglionic  centres,  without  the  necessary  intervention  of  consciousness. 
These  centres  are  connected  with  each  other  commissurally,  when  they  are  re- 
quired to  act  with  consentaneousness  j  and  it  is  frequently  to  be  observed  in  the 
most  developed  forms  of  each  type,  that  they  come  into  actual  coalescence,  their 
functional  distinctness  being  still  indicated,  however,  by  the  distribution  of  their 
nervous  trunks. 

IV.  In  all  but  the  very  lowest  Invertebrata,  the  nervous  system  includes,  in 
addition  to  the  foregoing,  certain  ganglionic  centres,  situated  in  the  neighbor- 
hood of  the  entrance  to  the  digestive  cavity,  and  connected  with  certain  organs, 
which,  from  their  more  or  less  close  resemblance  to  our  own  instruments  of 
special  sense,  we  conclude  to  be  organs  of  sight,  smell,  hearing,  &c.  Now  as 
we  know  from  our  own  experience,  that  impressions  made  upon  these  organs 
produce  no  further  change  unless  we  become  conscious  of  them,  and  as  the  In- 
vertebrata possess  no  distinct  ganglionic  centres  of  a  higher  character,  it  seems 
to  be  a  legitimate  inference  that  these  "sensorial"  ganglia  are  the  instruments 
by  which  the  animals  furnished  with  them  are  rendered  cognizant  of  such  im- 
pressions, and  through  which  the  sensations  thus  called  into  existence  serve  to 
prompt  and  direct  their  movements.  What  is  commonly  designated  as  the 
"brain"  of  Invertebrata  (more  properly  their  "cephalic  ganglia")  cannot  be 
shown  to  consist  of  anything  else  than  an  assemblage  of  sensorial  centres ;  and 
its  actions  appear  to  be  entirely  of  a  "reflex"  character,  such  of  the  movements 
of  these  animals  as  are  not  excito-motor  being  performed  (there  is  strong  reason 
to  believe)  in  respondence  to  sensations  excited  by  internal  or  external  impres- 
sions. Such  movements,  therefore,  may  be  designated  as  sensor i-motor,  or  con- 
sensual. Like  the  preceding,  they  must  be  accounted  purely  "automatic,"  since 
neither  emotion,  reason,  nor  will  has  any  participation  in  them ;  and  the  propor- 
tion which  they  bear  to  the  actions  of  the  excito-motor  kind  seems  to  correspond 
pretty  closely  with  the  relative  development  of  the  cephalic  ganglia  and  of  the 
rest  of  the  nervous  system,  is  very  obvious  when  the  larva  and  imago  states 
of  Insects  are  compared.  However  disjoined  the  various  excito-motor  centres 
may  be  amongst  each  other,  we  uniformly  find  them  connected  with  the  cephalic 
ganglia  by  commissural  tracts ;  and  this  anatomical  fact,  with  many  phenomena 
which  observation  and  experiment  upon  their  actions  have  brought  to  light, 
makes  it  apparent,  that  besides  the  reflex  actions  which  are  performed  through 
their  own  direct  instrumentality,  the  sensory  ganglia  have  a  participation  in 
those  performed  through  other  ganglionic  centres.  Thus  it  seems  probable  that 
a  stimulus  transmitted  downwards  from  the  sensory  ganglia,  to  one  of  the  gan- 
glia of  the  trunk  of  a  Centipede,  excites  the  efferent  nerves  of  that  ganglion  to 
call  into  contraction  the  muscles  supplied  by  them,  just  as  the  excitor  influence 
arriving  at  that  ganglion  through  its  own  afferent  nerve  would  do. 

675.  The  whole  Nervous  System  of  Invertebrated  animals,  then,  may  be 
regarded  as  ministering  entirely  to  automatic  action ;  and  its  highest  develop- 
ment, as  in  the  class  of  Insects,  is  coincident  with  the  highest  manifestations  of 
the  "  instinctive"  powers,  which,  when  carefully  examined,  are  found  to  consist 
entirely  in  movements  of  the  excito-motor  and  sensori-motor  kinds.  When  we 
attentively  consider  the  habits  of  these  animals,  we  find  that  their  actions, 
though  evidently  adapted  to  the  attainment  of  certain  ends,  are  very  far  from 
evincing  a  designed  adaptation  on  the  part  of  the  beings  that  perform  them, 


GENERAL    SUMMARY.  643 

such  as  that  of  which  we  are  ourselves  conscious  in  our  own  voluntary  move- 
ments, or  which  we  trace  in  the  operations  of  the  more  intelligent  Vertebrata. 
For,  in  the  first  place,  these  actions  are  invariably  performed  in  the  same  man- 
tier  by  all  the  individuals  of  a  species,  when  the  conditions  are  the  same ;  and 
thus  are  obviously  to  be  attributed  rather  to  a  uniform  impulse,  than  to  a  free 
choice ;  the  most  remarkable  examples  of  this  being  furnished  by  the  economy 
of  Bees,  Wasps,  and  other  "  social"  Insects,  in  which  every  individual  of  the 
community  performs  its  appropriate  part,  with  the  exactitude  and  method  of  a 
perfect  machine.  The  very  perfection  of  the  adaptation,  again,  is  often  of  it- 
self a  sufficient  evidence  of  the  unreasoning  character  of  the  beings  which  per- 
form the  work  ;  for,  if  we  attribute  it  to  their  own  intelligence,  we  must  admit 
that  this  intelligence  frequently  equals,  if  it  does  not  surpass,  that  of  the  most 
accomplished  Human  reasoner.1  Moreover,  these  operations  are  performed 
without  any  guidance  from  experience ;  for  it  can  be  proved  in  many  cases,  that 
it  is  impossible  for  the  beings  which  execute  them  to  have  received  any  instruc- 
tion from  their  parents ;  and  we  see  that  they  do  not  themselves  make  any  pro- 
gressive attempts  towards  perfection,  but  accomplish  their  work  as  well  when 
they  first  apply  themselves  to  it,  as  after  any  number  of  repetitions  of  the  same 
acts.  It  is  interesting  to  observe,  moreover,  that  as  these  instinctive  operations 
vary  at  different  periods  of  life;  so  is  there  a  corresponding  variation  in 
the  structure  of  the  Nervous  system.  Thus  we  see  that,  in  the  larva  of  the 
Insect,  these  operations  are  entirely  directed  towards  the  acquisition  of  food ; 
and  its  organs  of  sense  and  locomotive  powers  are  only  so  far  developed  as  to 
serve  this  purpose.  But  in  the  imago  or  perfect  Insect,  the  primary  object  is 
the  continuance  of  the  race;  and  the  sensorial  and  motor  endowments  are 
adapted  to  enable  the  individual  to  seek  its  mate,  and  to  make  preparations  (fre- 
quently of  a  most  elaborate  kind)  for  the  nurture  of  the  offspring.  Hence  we 
can  scarcely  fail  to  arrive  at  the  conclusion,  that  the  adaptiveness  of  the  instinct- 
ive operations  of  Insects,  &c.,  lies  in  the  original  construction  of  their  nervous 
system,  which  causes  particular  movements  to  be  executed  in  direct  respondence 
to  certain  impressions  and  sensations.  And  this  view  is  confirmed  by  the  com- 
parison of  these  movements  with  those  which  have  been  always  recognized  as 
u  instinctive"  in  the  Human  being ;  thus,  the  act  of  sucking  in  the  infant  re- 
quires the  combined  exertion  of  a  considerable  number  of  muscles,  which  com- 
bination is  clearly  not  the  result  of  intelligence  and  will,  but  is  a  purely  "  reflex" 

1  Of  this  we  have  a  most  remarkable  example  in  the  architecture  of  the  common  Hive- 
Bee. — The  hexagonal  form  of  the  cell  is  the  one  in  which  the  greatest  strength,  and  the 
nearest  approach  to  the  cylindrical  cavity  required  for  containing  the  larva,  are  attained, 
with  the  least  expenditure  of  material.  But  the  instinct  which  directs  the  Bees  in  the 
construction  of  the  partition  that  forms  the  bottom  or  end  of  the  cell,  is  of  a  nature  still 
more  wonderful  than  that  which  governs  its  general  shape.  The  bottom  of  each  cell 
rests  upon  three  partitions  of  cells  upon  the  opposite  side  of  the  comb ;  so  that  it  is  ren- 
dered much  stronger,  than  if  it  merely  separated  the  cavities  of  two  cells  opposed  to  one 
another.  The  partition  is  not  a  single  plane  surface ;  but  is  formed  by  the  union  of 
three  rhomboidal  planes,  uniting  in  the  centre  of  each  cell.  The  angles  formed  by  the 
sides  of  these  rhombs  were  determined  by  the  measurements  of  Miraldi  to  be  109°  28' 
and  70°  32'  ;  and  these  have  been  shown,  by  mathematical  calculation,  to  be  precisely  the 
angles,  at  which  the  greatest  strength  and  capacity  can  be  attained,  with  the  least  expen- 
diture of  wax.  The  solution  of  the  problem  was  first  attempted  by  Koenig,  a  pupil  of  the 
celebrated  Bernouille  ;  and  as  his  result  proved  to  differ  from  the  observed  angle  by  only 
two  minutes  of  a  degree,  it  was  presumed  that  the  discrepancy  was  due  to  an  error  of  ob- 
servation, which  it  was  easy  to  account  for  by  the  smallness  of  the  surfaces  whose  incli- 
nation had  to  be  measured.  The  question  has  been  since  taken  up,  however,  by  Lord 
Brougham  (Appendix  to  his  Illustrated  edition  of  "Paley's  Natural  Theology");  who 
has  worked  it  out  afresh,  and  has  shown  that,  when  certain  small  quantities,  neglected  by 
Koenig,  are  properly  introduced  into  the  calculation,  the  result  is  exactly  accordant  with 
observation — the  Bees  being  thus  proved  to  be  right,  and  the  Mathematician  wrong. 


644  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

act  (§  423)  }  and  the  same  may  be  said  of  the  acts  of  coughing  and  sneezing 
(§  555),  the  purpose  of  which  is  most  obvious,  and  the  adaptation  to  that  pur- 
pose most  complete,  yet  these  acts  are  most  assuredly  not  performed  with  any 
notion  of  their  purpose,  but  at  the  prompting  of  an  irresistible  impulse,  which, 
originating  in  an  excitation  applied  to  a  sensory  surface  and  conveyed  to  the  au- 
tomatic centres,  becomes  the  immediate  source  of  all  the  separate  muscular  con- 
tractions which  combine  to  accomplish  the  prearranged  result.1 

676.  Thus,  then,  the  type  of  psychical  perfection  among  Invertebrated  ani- 
mals, which  is  manifested  in  the  highest  degree  in  the  Social  Insects,  consists  in 
the  exclusive  development  of  the  Automatic  powers;  in  virtue  of  which,  each 
individual  performs  those  actions  to  which  it  is  directly  prompted  by  the  im- 
pulses arising  out  of  impressions  made  upon  its  afferent  nerves,  without  any 
self-control  or  self-direction  ;  so  that  it  must  be  regarded  as  entirely  a  creature 
of  necessity,  performing  its  instrumental  part  in  the  economy  of  Nature  from 
no  design  or  will  of  its  own,  but  in  accordance  with  the  plan  originally  devised 
by  its  Creator.  On  turning  to  the  Vertebrated  series,  on  the  other  hand,  we 
find  that  perfection  consists  in  the  highest  development  of  the  Intelligence,  and 
in  the  supreme  domination  of  the  Will,  to  which  all  the  automatic  movements, 
save  those  which  are  absolutely  essential  to  the  maintenance  of  the  organic 
functions,  are  brought  under  subjection ;  so  that  each  individual  becomes  an 
independent,  self-moving,  and  self-controlling  agent,  all  whose  actions  are  per- 
formed with  a  definite  purpose  which  is  distinctly  before  his  own  view,  and  are 
adapted  to  the  attainment  of  their  end  by  his  own  reason.  This,  however,  is 
only  true  of  Man  in  his  highest  state  of  psychical  development ;  for  not  only 
do  the  actions  of  the  lower  Vertebrata  appear  to  be  nearly  as  much  under  tho 
direction  of  automatic  impulses  as  are  those  of  the  Invertebrated  classes,  but 
the  same  is  true  of  those  of  the  Human  species  in  infancy  and  early  childhood ; 
and  a  very  close  correspondence  may  be  traced  between  the  gradual  develop- 
ment of  the  Intelligence  and  the  progressive  acquirement  of  Volitional  domi- 
nance, in  the  ascending  series  of  Vertebrated  animals,  and  in  the  advance  of 
Man  from  the  mental  state  of  childhood  (which  is  permanently  retained,  as  to 
all  its  essential  characters,  in  many  adults,  and  even  in  whole  races  of  the  least 
cultivated  order)  to  the  highest  elevation  which  his  nature  is  capable  of  display- 
ing in  his  present  sphere  of  existence. — The  superaddition  of  these  more  ele- 
vated psychical  endowments  is  coincident  with  the  addition  of  a  peculiar  gan- 
glionic  centre,  the  Cerebrum,  to  the  automatic  apparatus  of  Vertebrated  ani- 
mals ;  and  the  relative  proportion  which  this  bears  to  the  automatic  centres, 
both  as  to  size  and  complexity  of  structure,  corresponds  so  closely  with  the 
degree  of  predominance  which  the  Intelligence  and  Will  possess  over  the  In- 
stinctive propensities,  that  it  is  scarcely  possible  to  doubt  that  the  Cerebrum  is 
the  instrument  through  which  these  higher  psychical  powers  are  exercised.  Even 
in  Man,  however,  the  Automatic  division  of  the  Nervous  system  still  constitutes 

1  We  have  not,  perhaps,  any  right  to  affirm  that  there  is  nothing  whatever  analogous  in 
the  Invertebrata  to  the  Reasoning  powers  and  Will  of  higher  animals;  but  if  these 
faculties  have  any  existence  among  them,  they  must  be  regarded  as  in  a  merely  rudiment- 
ary state,  corresponding  with  the  undeveloped  condition  of  the  Cerebrum.  In  none  of 
the  Articulata  has  any  trace  of  this  organ  been  discovered  ;  a  rudiment  of  it,  however, 
has  been  supposed  to  exist  in  the  Cuttle-fish.  The  only  distinct  indication  of  intelligence 
displayed  by  Invertebrata  is  the  slight  degree  of  capacity  of  "learning  by  experience" 
which  some  of  them  display  ;  this  capacity  being  limited  to  the  mere  formation  of  asso- 
ciations between  the  mental  states  called  up  by  different  objects  of  sense,  which  we  observe 
to  be  the  first  stage  in  the  development  of  the  mental  powers  in  the  Human  infant.  And 
it  is  interesting  to  remark  that  this  educability  is  less  displayed  by  Insects,  in  which  we 
may  consider  the  Automatic  tendencies  as  attaining  their  highest  development,  than  it  is 
in  Spiders,  which  present  in  several  points  of  their  conformation  an  approximation  to  wards 
the  Vertebrated  series. 


GENERAL    SUMMARY.  645 

its  fundamental  and  essential  part;  for  not  only  is  it  the  instrument  of  all 
those  actions  which  are  directly  excited  by  sensations  or  impressions  derived 
from  without,  many  of  these  being  necessary  to  the  maintenance  of  his  organic 
functions;  but  it  is  also  the  connecting  link  between  the  Cerebrum  and  the 
external  world.  For,  as  will  appear  hereafter,  the  Cerebrum  receives  all  its  sti- 
mulus to  action  through  the  sensorial  ganglia,  to  which  all  the  proper  sensory 
nerves  are  traceable;  whilst  on  the  other  hand,  in  carrying  into  effect  the 
mandates  of  the  will,  it  does  not  operate  directly  upon  the  muscles,  but  affects 
them  through  the  instrumentality  of  the  Automatic  motor  apparatus. 

677.  The  dominant  character  of  the  Nervous  System  in  Yertebrated  animals 
is  marked  by  the  subserviency  of  the  whole  organism  to  its  purposes.     In  a 
large  proportion  of  the  Invertebrata,  the  Nervous  system  seems  like  an  append- 
age  to  the  rest  of  the  structure,   a  mechanism  superadded  for  the  sake  of 
bringing  its  various  parts  into  more  advantageous  relation;  and  we  do  not  find 
any  special  adaptation  of  the  organs  of  support  for  its  protection.     But  in  all 
the  Vertebrated  classes,  we  find  that  the  internal  osseous  skeleton,  whose  exist- 
ence supplies  the  most  distinctive  character  of  the  group,  is  adapted  not  merely 
to  furnish  the  most  complete  and  efficient  protection  to  the  Nervous  centres, 
but  also  to  afford  points  of  attachment  to  the  Muscles,  as  well  as  a  system  of 
inflexible  levers  on  which  they  may  exert  the  contractile  power  called  forth  by 
the  nerves;  so  that  the  development  of  the  neuro-skeleton  (thus  designated  in 
contradiction  to  the  dermo-skeleton)  has  a  constant  relation  to  that  of  the  Nervo- 
muscular  apparatus.     This  is  most  remarkably  seen  in   Man;  in  whom  the 
"archetype"  or  fundamental  plan  of  the  Vertebral  skeleton  is  most  departed  from, 
in  order  that  it  may  be  adapted  to  his  special  requirements.1     And  it  is  in  him, 
too,  that  the  Nervous  system  presents  the  greatest  proportionate  development, 
and  that,  by  the  intimate  connections  which  subsist  between  its  several  parts,  it 
is  made  so  far  to  constitute  one  whole,  that  the  determination  of  their  respective 
functions  is  attended  with  the  greatest  difficulty.     It  has  been,  in  fact,  through 
the  too  exclusive  attention  commonly  paid  to  Human  Anatomy,  that  the  mean- 
ing of  the  facts  brought  to  light  by  dissection  has  been  very  commonly  misap- 
prehended; and  that  many  of  the  physiological  interpretations  based  upon  them, 
have  been  completely  negatived  by  more  extended  inquiry. — It  is  only,  in  fact, 
by  studying  the  Cerebro-Spinal  apparatus  in  its  lowest,  as  well  as  in  its  highest 
form,  and  by  bringing  the  intervening  grades  into  comparison  with  both  extremes, 
that  it  is  possible  to  establish  what  are  its  fundamental  or  essential,  and  what  its 
accessory  parts ;  and  in  this  way  only  can  such  a  correspondence  be  established 
between  the  development  of  a  particular  structure,  and  the  manifestation  of  a 
certain  psychical  endowment,  as  may  enable  the  latter  to  be  attributed  with  any 
degree  of  probability  to  the  former.     In  fact,  there  is  no  part  of  the  Human 
Organism,  as  to  which  the  advantages  of  such  a  comparison  are, so  striking,  or 
in  which  the  value  of  the  "  experiments  ready  prepared  for  us  by  Nature"  is  so 
much  above  that  of  the  results  of  artificial  mutilations. 

678.  Under  the  guidance,  then,  of  these  principles,  we  find  that  we  may 
distinguish,   as  the  fundamental  part  of  the   Nervous  system  of  Man,   the 
Cranio- Spinal  Axis,  consisting  of  the  Spinal  Cord,  the  Medulla  Oblongata,  and 
the  Sensory  Ganglia,  and  altogether  constituting  the  centre  of  automatic  move- 
ment.— The  Spinal   Cord,  consisting  of  a  tract  of  vesicular  matter  inclosed 
within  strands  of  longitudinal  fibres,  and  giving  off  successive  pairs  of  inter- 
vertebral  nerves  which  are  connected  at  their  roots  with  both  of  these  components, 
is  obviously  homologous  with  the  gangliated  ventral  column  of  the  Articulata, 
differing  from  it  only  in  the  continuity  of  the  ganglionic  substance  which  occupies 

1  See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  g  326,  k,  Am.  Ed. 


646  OF   THE   FUNCTIONS   OF   THE   NERVOUS   SYSTEM. 

its  interior;  and  each  segmental  division  of  it,  which  serves  as  the  centre  for- 
its  own  pair  of  nerves,  may  be  considered,  like  each  ganglion  of  the  ventral 
column  of  the  Articulata,  as  a  repetition  of  the  single  "pedal"  or  locomotive 
ganglion  of  the  Mollusca. — The  Medulla  Oblongata  consists  of  a  set  of  strands, 
which  essentially  correspond  with  the  cords  that  pass  round  the  oesophagus  in 
Invertebrated  animals,  connecting  the  cephalic  ganglia  with  the  first  sub-cesopha- 
geal  ganglion ;  but,  as  the  whole  cranio-spinal  axis  in  the  Vertebrata  lies  above 
the  alimentary  canal  (the  trunk  being  supposed  to  be  in  a  horizontal  position), 
there  is  no  such  divergence  of  these  strands,  the  only  separation  between  them 
being  that  which  is  known  as  the  "  fourth  ventricle/'  Interposed  among  the 
commissural  fibres  of  the  Medulla  Oblongata,  however,  are  certain  collections  of 
vesicular  matter,  which  serve  as  the  ganglionic  centres  for  the  movements  of 
respiration  and  deglutition,  and  which  thus  correspond  with  the  respiratory  and 
stomato-gastric  ganglia  of  Invertebrated  animals.  This  incorporation  of  so 
many  distinct  centres  into  one  system  would  seem  destined  in  part  to  afford  to  all 
of  them  the  protection  of  the  vertebral  column ;  and  in  part  to  secure  that  con- 
sentaneousness  of  action  and  that  ready  means  of  mutual  influence  which  are 
peculiarly  requisite  in  beings  in  whom  the  activity  of  the  Nervous  system  is  so 
predominant.  Thus  the  close  connection  which  is  established  in  the  higher 
Vertebrated  animals,  between  the  respiratory  and  the  general  locomotive  appa- 
ratus, is  obviously  subservient  to  the  use  which  the  former  makes  of  the  latter 
in  the  performance  of  its  functions;  whilst,  on  the  other  hand,  the  control 
which  their  encephalic  centres  possess  over  the  actions  of  the  respiratory  ganglia 
enables  the  will  to  regulate  the  inspiratory  and  expiratory  movements  in  the 
manner  required  for  the  acts  of  vocalization. — Under  the  term  Sensory  Ganglia 
may  be  comprehended  that  assemblage  of  ganglionic  masses  lying  along  the  base 
of  the  skull  in  Man,  and  partly  included  in  the  Medulla  Oblongata,  in  which 
the  nerves  of  the  "special  senses,"  Taste,  Hearing,  Sight,  and  Smell,  have  their 
central  terminations ;  and  with  these  may  probably  be  associated  the  two  pairs 
of  ganglionic  bodies  known  as  the  Corpora  Striata  and  Thalami  Optici,  into 
which  may  be  traced  the  greater  proportion  of  the  fibres  that  constitute  the 
various  strands  of  the  Medulla  Oblongata,  and  which  seem  to  stand  in  the 
same  kind  of  relation  to  the  nerves  of  Touch  or  "common  sensation,"  that  the 
Olfactive,  Optic,  Auditory,  and  Gustative  ganglia  bear  to  their  several  nerve- 
trunks. 

679.  Now  it  is  not  a  little  interesting,  that  this  Cranio-Spinal  axis,  which 
represents  in  Vertebrated  animals  the  whole  nervous  system  of  the  Invertebrata 
(with  the  exception  of  the  rudiment  of  the  Sympathetic  which  they  possess), 
should  exist  in  the  lowest  known  Vertebrated  animal  without  any  superaddi- 
tion,  and  should  be  sufficient  for  the  performance  of  all  its  actions.  Such  is  the 
case  in  the  curious  Amphioxus*  which  presents  not  the  slightest  trace  of  either 
Cerebrum  or  Cerebellum,  and  in  which  even  the  sensory  ganglia  and  the  organs 
of  special  sense  have  only  a  rudimentary  existence ;  and  in  which,  too,  the 
spinal  cord  is  composed  of  a  series  of  ganglia  that  are  obviously  distinct  from 
each  other,  although  in  close  approximation.  And  even  in  the  lower  Cyclos- 
tome  Fishes,  the  condition  of  the  nervous  centres  is  very  little  above  this,  save 
as  regards  the  larger  development  of  the  sensory  ganglia.  This  condition  has 
its  parallel,  even  in  the  Human  species,  in  the  case  of  Infants  which  are  occa- 
sionally born  without  either  Cerebrum  or  Cerebellum ;  such  have  existed  for 
several  hours  or  even  days,  breathing,  sucking,  crying,  and  performing  various 
other  movements;  and  there  is  no  physiological  reason  why  their  lives  should 
not  be  prolonged,  if  they  be  nurtured  with  sufficient  care  (§  373). 

1  "Princ.  of  Phys.   Gen.  and  Comp.,"  \  321,  Am.  Ed. 


GENERAL   SUMMARY. 


647 


Fig.  171. 


Brain  of    Cod: — 

A,  olfactive  ganglia ; 

B,  cerebral    lobes ; 
c,    optic     ganglia ; 
D,  cerebellum. 


680.  In  Man,  however,  as  in  all  the  higher  Vertebrata,  we  find  superimposed 
(as  it  were)  upon  the  Sensory  ganglia,  and  constituting  the 

principal  mass  of  the  Encephalon,  the  bodies  which  are  known 
as  the  Cerebral  Hemispheres,  or  Hemispheric  Ganglia.  Now 
when  these  are  so  greatly  developed  as  to  cover  in  and  obscure 
the  Sensory  ganglia  to  the  degree  which  presents  itself  in  Man, 
it  is  not  surprising  that  the  fundamental  importance  of  the 
latter  should  not  be  generally  recognized ;  in  Fishes,  however, 
the  proportion  between  the  two  sets  of  centres  is  entirely  re- 
versed, the  rudiments  of  the  Cerebral  Hemispheres  (Fig.  171, 
B)  being  usually  inferior  in  size  to  the  Optic  ganglia  (c)  alone. 
Indeed,  of  the  pair  of  ganglionic  masses  to  which  that  designa- 
tion is  usually  applied,  it  may  be  almost  positively  stated  that 
the  greater  part  is  homologous  with  the  Corpora  Striata  of  the 
Human  brain  ;  it  being  only  in  the  higher  Cartilaginous  fishes 
that  a  ventricular  cavity  exists  in  each  of  these  bodies,  sepa- 
rating the  thin  layer  of  true  Cerebral  substance  which  overlies 
it,  from  the  ganglionic  mass  which  forms  its  floor.  Between 
these  two  extremes,  a  regular  gradation  is  presented  in  the  in- 
termediate tribes. — Now  it  is  a  point  especially  worthy  of  note, 
that  no  sensory  nerves  terminate  directly  in  the  Cerebrum,  nor 
do  any  motor  nerves  issue  from  it ;  and  there  seems  a  strong 
probability  that  there  is  not,  as  formerly  supposed,  a  direct 
continuity  between  any  or  all  of  the  nerve-fibres  distributed  to 
the  body,  and  the  medullary  substance  of  the  Cerebrum. 
For,  whilst  the  nerves  of  "  special"  sense  have  their  own  gan- 
glionic centres,  it  cannot  be  shown  that  the  nervous  fibres  of 
"general"  sense  which  either  enter  the  cranium  as  part  of  the  cephalic  nerves, 
or  which  pass  up  from  the  Spinal  cord,  have  any  higher  destination  than  the 
Thalami  Optici.  So  the  motor  fibres  which  pass  forth  from  the  cranium  either 
into  the  cephalic  nerve-trunks  or  into  the  motor  columns  of  the  Spinal  cord, 
cannot  be  certainly  said  to  have  a  higher  origin  than  the  Corpora  Striata. 
And  we  shall  find  strong  physiological  ground  for  the  belief  that  the  Cerebrum 
has  no  communication  with  the  external  world,  otherwise  than  by  the  Sensori- 
motor  apparatus  which  ministers  to  the  automatic  actions ;  and  that  even  the 
movements  which  are  usually  designated  as  "voluntary"  are  only  so  as  regards 
their  original  source,  the  power  which  calls  the  muscles  into  contraction  being 
even  then  immediately  derived  from  the  Cranio-Spinal  axis,  as  it  is  in  the  purely 
automatic  movements  excited  by  an  external  impression. 

681.  Wherever  a  Cerebrum  is  superimposed  upon  the  Sensory  Ganglia,  we 
find  another  ganglionic  mass,  the  Cerebellum,  superimposed  upon  the  Medulla 
Oblongata.     The  development  of  this  organ  bears  a  general,  but  by  no  means  a 
constant  relation  to  that  of  the  Cerebrum  j  for  in  the  lowest  Fishes  it  is  a  thin 
lamina  of  nervous  matter  on  the  median  line,  only  partially  covering  in  the 
"  fourth  ventricle  ;"  whilst  in  the  higher  Mammalia,  as  in  Man,  it  is  a  mass  of 
considerable  size,  having  two  lateral  lobes  or  hemispheres  in  addition  to  its 
central  portion.     The  direct  communication  which  the  Cerebellum  has  with 
both  columns   of  the   Spinal  cord,  and  the  comparatively  slight   commissural 
connection  which  it  possesses  with  the  higher  portions  of  the  Encephalic  centres, 
justify  the  supposition  that  it  is  rather  concerned  in  the  regulation  and  co-ordi- 
nation of  the  actions  of  the  former,  than  in  any  proper  psychical  operations ; 
and  it  will  hereafter  be  shown  that  the  evidence  afforded  by  Comparative  Ana- 
tomy, by  Experimental  inquiry,  and  by  Pathological  observation,  all  tends  to 
support  this  view  of  its  function. 

682.  Now  although  every  segment  of  the  Spinal  Cord  and  every  one  of  the 


648  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

Sensory  G-anglia,  may  be  considered,  in  common  with  the  Cerebrum,  as  a  true 
and  independent  centre  of  nervous  power,  yet  this  independence  is  only  mani- 
fested when  these  organs  are  separated  from  each  other,  either  structurally — by 
actual  division,  or  functionally — by  the  suspension  of  the  activity  of  other  parts. 
In  their  state  of  perfect  integrity  and  complete  functional  activity,  they  are  all 
(at  least  in  Man)  in  such  subordination  to  the  Cerebrum,  that  they  only  minister 
to  its  actions,  except  in  so  far  as  they  are  subservient  to  the  maintenance  of  the 
organic  functions,  as  in  the  automatic  acts  of  breathing  and  swallowing.  "With 
regard  to  every  other  action,  the  Will,  if  it  possess  its  due  predominance,  can 
exercise  a  determining  power ;  keeping  in  check  every  automatic  impulse,  and 
even  repressing  the  promptings  of  emotional  excitement.  And  this  seems  to 
result  from  the  peculiar  arrangement  of  the  nervous  apparatus ;  which  causes  the 
excitor  impression  to  travel  in  the  upward  direction,  if  it  meet  with  no  inter- 
ruption, until  it  reaches  the  Cerebrum,  without  exciting  any  reflex  movements 
in  its  course.  When  it  arrives  at  the  Sensorium,  it  makes  an  impression  on  the 
consciousness  of  the  individual,  and  thus  gives  rise  to  a  sensation ;  and  the  change 
thus  induced,  being  further  propagated  from  the  sensory  ganglia  to  the  Cerebrum, 
becomes  the  occasion  of  the  formation  of  an  idea.  If  with  this  idea  any  pleasur- 
able or  painful  feeling  should  be  associated,  it  assumes  the  character  of  an  emo* 
tion;  and  either  as  a  simple  or  as  an  emotional  idea,  it  becomes  the  subject  of 
intellectual  operations,  whose  final  issue  is  in  a  volitional  determination,  or  acfc 
of  the  Will,  which  may  be  exerted  in  producing  or  checking  a  muscular  move-* 
ment,  or  in  controlling  or  directing  the  current  of  thought. 

683.  But  if  this  ordinary  upward  course  be  anywhere  interrupted,  the  im- 
pression will  then  exert  its  power  in  a  transverse  direction,  and  a  "  reflex"  ac- 
tion will  be  the  result,  the  nature  of  this  being  dependent  upon  the  part  of  the 
Cerebro-Spinal  axis  at  which  its  ascent  had  been  checked.  Thus,  if  the  inter- 
ruption be  produced  by  division  or  injury  of  the  Spinal  Cord,  so  that  its  lower 
part  is  cut-off  from  communication  with  the  encephalic  centres,  this  portion  then 
acts  as  an  independent  centre,  and  impressions  made  upon  it  through  the  afferent 
nerves  proceeding  to  it  from  the  lower  extremities,  excite  violent  reflex  move- 
ments, which,  being  thus  produced  without  sensation,  are  designated  as  "  excito- 
motor." — So,  again,  if  the  impression  should  be  conveyed  to  the  Sensorium,  but 
should  be  prevented  by  the  removal  of  the  Cerebrum,  or  by  its  state  of  func-» 
tional  inaction,  or  by  the  direction  of  its  activity  into  some  other  channel,  from 
calling  forth  ideas  through  its  instrumentality,  they  may  react  upon  the  motolr 
apparatus  by  the  "  reflex"  power  of  the  Sensory  ganglia  themselves ;  as  seems 
to  be  the  case  with  regard  to  those  locomotive  actions  which  are  maintained 
and  guided  by  sensations  during  states  of  profound  abstraction,  when  the  atten- 
tion of  the  individual  is  so  completely  concentrated  upon  his  own  train  of  thought 
that  he  does  not  perceive  external  objects,  although  his  movements  are  obviously 
guided  through  the  visual  and  tactile  senses.  Such  actions,  being  dependent 
upon  the  prompting  of  sensations,  are  "sensori-motor"  or  "  consensual." — But 
further,  there  is  evidence  that  even  the  Cerebrum  may  respond  (as  it  were)  au- 
tomatically to  impressions  fitted  to  excite  it  to  "reflex"  action,  when  from  any 
cause  the  Will  is  in  abeyance,  and  its  power  cannot  be  exerted  either  over  the 
muscular  system  or  over  the  direction  of  the  thoughts.  Thus  in  the  states  of 
Dreaming,  Somnambulism,  and  even  Reverie,  whether  spontaneous  or  artificially 
induced  (Sect.  7),  ideas  which  take  possession  of  the  mind,  and  from  which  it 
cannot  free  itself,  may  excite  respondent  movements;  and  this  may  happen  also 
when  the  force  of  the  idea  is  morbidly  exaggerated,  and  the  will  is  not  suspended 
but  merely  weakened,  as  in  many  forms  of  Insanity.  With  these  ideas,  more- 
over, Emotional  states  may  be  mixed  up,  and  even  Intellectual  processes  may  be 
prompted  by  them;  so  long,  however,  as  these  psychical  operations  take  place  at 
the  mere  suggestion  of  antecedent  impressions  (the  particular  changes  which  these 


GENERAL   SUMMARY.  649 

• 

suggestions  excite  being  determined  by  the  mental  constitution  and  habits  of 
thought  of  the  individual),  so  long  must  the  actions  proceeding  from  them  be 
considered  as  manifestations  of  the  "reflex"  power  of  the  Cerebrum,  and  conse- 
quently as  no  less  automatic  in  their  character,  than  are  those  which  result  from 
the  reflex  power  of  the  Cranio-Spinal  axis.  Those  actions  which  proceed  from 
simple  ideas,  without  any  excitement  of  feeling,  may  be  designated  as  ideo-motor  ; 
whilst  those  which  spring  from  a  passion  or  emotion  may  be  termed  emotional. 
The  automatic  nature  of  the  purely  emotional  actions  can  scarcely  be  denied; 
when  the  passions  are  strongly  excited,  their  impulses  even  acquire  the  mastery 
over  the  strongest  exertion  of  the  Will;  and  it  is  in  individuals  in  whom  the 
habitual  control  of  the  will  is  the  weakest,  that  we  observe  the  emotions  to  act 
most  powerfully  on  the  bodily  frame. 

684.  The  dominant  power  of  the  Will,  not  only  over  every  act  of  the  nervo- 
muscular  apparatus  which  is  not  immediately  concerned  in  the  maintenance  of 
the  vital  functions,  but  over  the  course  of  purely  psychical  action,  is  probably 
the  most  distinctive  attribute  of  the  Human  mind  in  its  highest  phase  of  deve- 
lopment; and  it  is  that  which  gives  to  each  individual  the  freedom  of  action, 
which  every  one  is  conscious  to  himself  that  he  is  capable  of  exerting.     Not- 
withstanding the  evidences  of  rationality  which  many  of  the  lower  animals  present, 
and  the  manifestations  which  they  display  of  emotions  that  are  similar  to  our 
own,  there  is  no  ground  to  believe  that  they  have  any  of  that  controlling  power 
over  their  psychical  operations  which  we  possess  :  on  the  contrary,  all  observa- 
tion seems  to  lead  to  the  conclusion,  that  they  are  under  the  complete  domina- 
tion of  the  ideas  and  emotions  by  which  they  are  for  the  time  possessed,  and 
have  no  power  either  of  repressing  these  by  a  forcible  act  of  Will,  or  of  turning 
the  attention,  by  a  like  voluntary  effort,  into  another  channel.     In  this  respect, 
then,  their  condition  resembles  that  of  the  dreamer,  the  somnambule,  or  the 
insane  patient,  in  all  of  whom  this  voluntary  control  is  suspended,  and  who 
(when  their  minds  are  susceptible  of  external  impressions)  may  be  so  "  played 
upon"  by  the  suggestion  of  ideas,  that  any  respondent  action  consistent  with 
the  habitual  mental  state  of  the  individual,  may  be  evoked  by  an  appropriate 
stimulus;  just  as  we  see  in  the  case  of  animals  that  are  trained  to  the  performance 
of  particular  sets  of  movements,  which  are  executed  in  respondence  to  certain 
promptings  conveyed  to  them  through  their  sensorium.     Now  between  the  com- 
plete want  of  this  controlling  power  of  the  Will,  and  the  most  perfect  possession 
of  it,  every  intermediate  gradation  is  presented  by  the  several  individuals  which 
make  up  the  Human  species ;  some  persons  being  so  much  accustomed,  in  con- 
sequence of  the  weakness  of  their  Will,  to  act  directly  upon  intellectual  or  emo- 
tional suggestions,  that  they  can  scarcely  be  said  to  be  voluntary  agents;  and 
others  allowing  certain  dominant  ideas  or  habitual  feelings  to  gain  such  a  mastery 
over  them,  as  to  exercise  that  determining  power  which  the  Will  alone  ought  to 
exert.     This  gradation  may  be  perfectly  traced  in  children,  in  whose  education 
the  development  of  the  faculty  of  " self-control"  should  be  a  leading  object;  and 
it  is  also  displayed  in  some  of  those  phases  of  mental  Imbecility,  which  result 
from  a  deficiency  of  the  power  of  fixing  the  attention  upon  any  object  of  con- 
sciousness, and  of  withdrawing  it  from  external  objects  that  tend  to  distract  the 
mind  by  suggesting  new  ideas  and  trains  of  thought.     On  this  power  of  self- 
direction,  indeed,  all  the  higher  developments  of  intellectual  power  almost  essen- 
tially depend ;  and  we  shall  hereafter  see  how  largely  it  is  concerned  in  that 
progressive  exaltation  of  the  Moral  nature,  which,  even  more  than  Intellectual 
capacity,  tends  to  bring  the  Human  soul  into  relation  with  its  Creator. 

685.  This  directing  power  of  the  Will  seems  to  be  most  strongly  exerted, 
however,  over  those  actions  which  are  most  closely  connected  with  psychical 
changes,  and  which  are  exclusively  Cerebral  in  their  seat.     It  has  been  already 
pointed  out,  that  the  Cranio-spinal  axis  not  merely  serves  as  the  channel  for  the 


650  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

reception  of  the  impressions  which  excite  the  activity  of  the  Hemispheric  gan- 
glia, and  as  the  instrument  whereby  the  results  of  their  operation  are  brought 
to  bear  upon  the  muscular  system ;  but  that  it  is  also  the  centre  of  reflexion 
through  which  various  automatic  movements  are  called  forth,  that  are  immedi- 
ately concerned  in  the  maintenance  of  the  organic  functions.  The  impressions 
which  excite  these  movements  do  not  in  general  pass  on  to  the  Cerebrum;  for 
we  only  perceive  them  when  we  specially  direct  our  attention  to  them,  or  when 
they  exist  in  unusual  potency.  Thus  we  are  unconscious  of  the  "besom  de  re- 
spirer"  by  which  our  ordinary  movements  of  respiration  are  prompted ;  and  it  is 
only  when  we  have  refrained  from  breathing  for  a  few  seconds,  that  we  experi- 
ence a  sensation  of  uneasiness  which  impels  us  to  make  forcible  efforts  for  its 
relief.  Notwithstanding,  however,  that  the  Cerebrum  is  thus  unconcerned  in 
the  ordinary  performance  of  these  automatic  movements,  yet  it  can  exert  a 
certain  degree  of  control  over  many  of  them,  so  as  even  to  suspend  them  for  a 
time;  but  in  no  instance  can  it  carry  this  suspension  to  such  an  extent  as 
seriously  to  disarrange  the  organic  functions ;  thus,  when  we  have  voluntarily 
refrained  from  breathing  for  a  few  seconds,  the  inspiratory  impulse  so  rapidly 
increases  in  strength  with  the  continuance  of  the  suspension,  that  it  at  last 
overcomes  the  most  powerful  effort  we  can  make  for  the  repression  of  the  move- 
ments to  which  it  prompts.  Now  in  this  and  similar  cases,  it  would  seem  as  if 
the  Will  interfered  to  prevent  that  direct  transverse  passage  of  the  stimulus 
from  the  afferent  to  the  efferent  nerves,  through  the  Cranio-Spinal  axis,  which 
constitutes  the  ordinary  line  of  action  for  impressions  having  their  origin  in  the 
necessities  of  the  organic  or  vegetative  life  of  the  individual.  That  the  Will 
should  have  a  certain  degree  of  control  over  these  movements,  is  necessary  in 
order  that  they  may  be  rendered  subservient  to  various  actions  which  are  neces- 
sary for  the  due  exercise  of  Man's  psychical  powers ;  but  that  they  should  not 
be  left  dependent  upon  its  exercise,  and  should  even  be  executed  in  opposition 
to  it,  when  the  wants  of  the  system  imperatively  demand  their  performance, 
constitutes  a  wise  provision  for  securing  Life  against  the  chances  of  inattention 
or  momentary  caprice. 

686.  The  general  views  here  put  forth  in  regard  to  the  independent  and  con- 
nected actions  of  the  several  primary  divisions  of  the  Cerebro-Spinal  apparatus, 
may  perhaps  be  rendered  more  intelligible  by  the  following  Table,  which  is  in- 
tended to  represent  the  ordinary  course  of  operation  when  the  whole  is  in  a 
state  of  complete  functional  activity  (§  682),  and  the  character  of  the  "reflex" 
actions  to  which  each  part  is  subservient,  when  it  is  the  highest  centre  that  the 
impression  can  reach  (§  683). 

WILL , 


Intellectual  operations — J  "] 

1    ! 

Emotions  __ 

centre  of  emotional  and  ideo-motor  reflection 

Ideas 


Sensations ^-»SENSORY  GANGLIA 


centre  of  sensori-motor  reflection 

Motor  Imnulse. 


Impressions S3  >SPINAL  CORD • 


centre  of  excito-motor  reflection 


GENERAL    SUMMARY.  651 

687.  Having  thus  considered  the  principal  attributes  of  the  ganglionic  centres 
of  the  Cerebro-Spinal  system,  we  have  next  to  inquire  into  those  of  the  nerve- 
trunks  which  are  connected  with  them.     It  is  only  in  the  Vertebrata  that  the 
difference  between  the  afferent  and  efferent  fibres  of  the  nerves  has  been  satis- 
factorily determined.     The  merit  of  this  discovery  is  almost  entirely  due  to  Sir 
C.  Bell,  who  was  led  to  it  by  a  chain  of  reasoning  of  a  highly  philosophical 
character;  and  although  his  first  experiments  on  the  Spinal  nerves  were  not 
satisfactory,  he  virtually  determined  the  respective  functions  of  their  two  roots, 
by  experiments  and  pathological  observations  upon  the  cranial  nerves,  some  of 
which  contain  only  one  class  of  fibres  to  the  exclusion  of  the  other,  before  any 
other  physiologist  came  into  the  field.1     Subsequently  his  general  views  were 
confirmed  by  the  very  decided  experiments  of  Miiller;  but  until  very  recently, 
some  obscurity  hung  over  a  portion  of  the  phenomena.     It  was  from  the  first 
maintained  by  Magendie,  and  has  been  subsequently  asserted  by  other  physi- 
ologists, that  the  anterior  and  posterior  roots  of  the  nerves  were  both  concerned 
in  the  reception  of  impressions  and  in  the  production  of  motions;  for  that, 
when  the  anterior  roots  were  touched,  the  animal  gave  signs  of  pain,  at  the  same 
time  that  convulsive  movements  were  performed :  and  that,  on  touching  the  pos- 
terior roots,  not  only  the  sensibility  of  the  animal  seemed  to  be  affected,  but 
muscular  motions  were  excited.    These  physiologists  were  not  willing,  therefore, 
to  admit  more  than  that  the  anterior  roots  were  especially  motor,  and  the  pos- 
terior especially  sensory.     But  the  knowledge  we  now  possess  of  the  reflex 
function  of  the  Spinal  Cord  enables  the  latter  portion  of  these  phenomena  to 
be  easily  explained.     The  motions  excited  by  irritating  the  posterior  roots  are 
found  to  be  entirely  dependent  upon  their  connection  with  the  Spinal  Cord,  and 
upon  the  integrity  of  the  anterior  roots  and  of  the  trunks  into  which  they  enter ; 
whilst  they  are  not  checked  by  the  separation  of  the  posterior  roots  from  the 
peripheral  portion  of  the  trunk :  it  is  evident,  therefore,  that  excitation  of  the 
posterior  roots  does  not  act  immediately  upon  the  muscles  through  the  trunk  of 
the  nerve,  which  they  contribute  to  form;  but  that  it  excites  a  motor  impulse 
in  the  Spinal  Cord,  which  is  propagated  through  the 'anterior  roots  to  the  peri- 
phery of  the  system.     The  converse  phenomenon,  the  apparent  sensibility  of 
the  anterior  roots,  has  been  explained  by  the  experiments  of  Dr.  Kroneuberg,2 
which  seem  to  prove  that  it  is  dependent  upon  a  branch  from  the  posterior 
roots  passing  into  the  anterior  roots  at  their  point  of  inosculation,  and  then 
directing  itself  towards  the  cord  (§  692). 

688.  Every  fibre,  there  is  reason  to  believe,  runs  a  distinct  course  between 
the  central  organ,  in  which  it  loses  itself  at  one  extremity,  and  the  muscle  or 
organ  of  sense  in  which  it  terminates  at  the  other.     Each  nervous  trunk  is 
made  up  of  several  fasciculi  of  these  fibres ;  and  each  fasciculus  is  composed  of 
a  large  number  of  the  ultimate  fibres  themselves.     Although  the  fasciculi  occa- 
sionally intermix  and  exchange  fibres  with  one  another  (as  occurs  in  what  is 
termed  a  plexus),  the  fibres  themselves  never  inosculate.     Each   fibre  would 
seem,  therefore,  to  have  its  appropriate  office,  which  it  cannot  share  with  another. 
— Several  objects  appear  to  be  attained  by  the  plexiform*  arrangement.     In  some 
instances  it  serves  to  intermix  fibres,  which  have  endowments  fundamentally 
different;  for  example,  the  Spinal  Accessory  nerve,  at  its  origin,  appears  to  be 
exclusively  motor,  and  the  roots  of  the  Pneumogastric  to  be  as  exclusively 
afferent ;  but  by  the  early  admixture  of  these,  a  large  number  of  motor  fibres 
are  imparted  to  the  Pneumogastric,  and  are  distributed  in  variable  proportion, 
with  its  different  branches ;  whilst  few  of  its  sensory  filaments  seem  to  enter 
the  Spinal  Accessory. — In  other  instances,  the  object  of  a  plexus  appears  to  be 

1  See  "Brit,  and  Foreign  Med.  Review,"  vol.  ix.  p.  140,  &c. 

2  "Muller's  Archiv.,"  1839,  Heft  v.;  and  "Brit,  and  For.  Med.  Rev.,"  vol.  ix.  p.  547. 


652  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

to  give  a  more  advantageous  distribution  to  fibres,  which  all  possess  correspond- 
ing endowments.  Thus  the  brachial  plexus  mixes  together  the  fibres  arising  from 
five  segments  of  the  spinal  cord,  and  sends  off  five  principal  trunks  to  supply  the 
arm.  Now,  if  each  of  these  trunks  had  arisen  by  itself,  from  a  distinct  segment 
of  the  spinal  cord,  so  that  the  parts  on  which  it  is  distributed  had  only  a  single 
connection  with  the  nervous  centres,  they  would  have  been  much  more  liable  to 
paralysis  than  at  present.  By  means  of  the  plexus,  every  part  is  supplied  with 
fibres  arising  from  each  segment  of  the  spinal  cord ;  and  the  functions  of  the 
whole  must  therefore  be  suspended,  before  complete  paralysis  of  any  part  can 
occur  from  a  cause  which  operates  above  the  plexus.  Such  a  view  is  borne  out 
by  direct  experiment ;  for  it  has  been  ascertained  by  Panizza  that  in  Frogs, 
whose  crural  plexus  is  much  less  complicated  than  that  of  Mammalia,  section 
of  the  roots  of  one  of  the  three  nerves  which  enter  into  it  produces  little 
effect  on  the  general  movements  of  the  limb;  and  that,  even  when  two  are 
divided,  there  is  no  paralysis  of  any  of  its  actions,  all  being  weakened  in  a 
nearly  similar  degree. — But,  as  Dr.  Gull  has  pointed  out,1  one  use  of  such  a 
plexus  as  the  brachial  or  the  crural  appears  to  be,  to  bring  the  muscles  which 
derive  their  nervous  supply  from  it,  into  relation  with  different  ganglionic  seg- 
ments of  the  Spinal  Cord ;  each  of  which  may  exert  a  diverse  action,  either  in 
virtue  of  its  own  endowments,  or  of  the  influence  of  the  will  upon  it ;  so  that 
groups  of  muscles  may  thus  be  associated  for  combined  actions.  All  considera- 
tion of  the  mode  in  which  we  make  use  of  our  muscles,  and  of  the  power 
which  we  have  over  them,  leads  to  the  conclusion  that  each  ganglionic  centre 
has  a  specific  and  limited  sphere  of  influence,  producing  certain  movements  and 
no  others  j  hence  for  the  execution  of  a  variety  of  movements  in  harmonious 
combination  with  each  other,  it  seems  requisite  that  the  nervous  supply  of  each 
muscle  should  be  derived  from  several  different  centres ;  and  thus  it  is  that  the 
complication  of  plexuses  comes  to  be  related  to  the  variety  of  movements  of 
the  parts  supplied  through  them. — It  is  not  a  little  interesting  to  remark  that 
arrangements  of  a  similar  kind  should  present  themselves  among  the  higher 
Invertebrata.  Thus,  in  Hymenopterous  Insects  (as  first  pointed  out  by  Mr. 
Newport),  there  is  a  plexiform  interlacement  between  the  nerves  of  the  anterior 
and  of  the  posterior  pairs  of  wings,  which  act  very  powerfully  together  j  whilst 
in  the  Coleoptera,  in  which  the  anterior  wings  are  converted  into  elytra,  and 
are  motionless  during  flight,  the  nerves  supplying  each  pair  run  their  course 
distinctly.  In  the  Octopus,  or  Poulp,  again,  the  trunks  which  radiate  from  the 
cephalic  mass  to  the  eight  large  arms  surrounding  the  head  are  connected  by  a 
circular  band,  forming  a  kind  of  plexus,  which  seems  to  contribute  to  the  very 
powerful  and  harmonious  movements  of  the  arms  of  this  Cephalopod. 

689.  The  following  statements,  in  which  the  doctrines  of  Prof.  Miiller3  are 
adopted  with  some  modifications  and  additions,  embody  the  general  principles 
ascertained  by  experiment,  respecting  the  transmission  of  sensory  and  motor 
impressions  along  the  nerves  which  respectively  minister  to  them.  Their 
rationale  will  be  at  once  understood,  from  the  facts  already  mentioned  in  re- 
gard to  the  isolated  character  of  each  fibril,  and  the  identity  of  its  endowments 
through  its  whole  course. 

I.  When  the  whole  trunk  of  a  sensory  nerve  is  irritated,  a  sensation  is  pro- 
duced, which  is  referred  by  the  mind  to  the  parts  to  which  its  branches  are 
ultimately  distributed ;  and  if  only  part  of  the  trunk  be  irritated,  the  sensation 
will  be  referred  to  those  parts  only  which  are  supplied  by  the  fibrils  it  contains. 
This  is  evidently  caused  by  the  production  of  a  change  in  the  sensorium,  cor- 
responding with  that  which  would  have  been  transmitted  from  the  peripheral 

1  "Gulstonian  Lectures  on  the  Nervous  System,"  in  "Medical  Times,"  1849,  p.  372. 

2  "Elements  of  Physiology,"  translated  by  Dr.  Baly  ;  pp.  G80,  080. 


GENERAL    SUMMARY.  653 

origins  of  the  nerves,  had  the  impression  been  made  upon  them.  Such  a  change 
only  requires  the  integrity  of  the  afferent  trunk,  Between  the  point  irritated 
and  the  sensorium,  and  is  not  at  all  dependent  upon  the  state  of  the  peripheral 
part  to  which  the  sensations  are  referred ;  for  this  may  have  been  paralyzed  by 
the  division  or  other  lesion  of  the  nerve,  or  may  have  been  altogether  separated 
as  in  amputation,  or  the  relative  position  of  its  parts  may  have  been  changed, 
as  in  autoplastic  operations.  So,  when  different  parts  of  the  thickness  of  the 
same  trunk  are  separately  and  successively  irritated,  the  sensations  are  succes- 
sively referred  to  the  several  parts  supplied  by  these  divisions.  This  may  be 
easily  shown  by  compressing  the  ulnar  nerve  in  different  directions,  where  it 
passes  at  the  inner  side  of  the  elbow-joint. — Still  the  mind  undoubtedly  does 
possess  a  certain  power  of  discriminating  the  part  of  the  nerve-trunk  on  which 
the  impression  is  made ;  for  whilst  this  impression  is  such  as  to  produce  sensa- 
tions that  are  referred  to  its  peripheral  extremities,  pain  is  at  the  same  time 
felt  in  the  spot  itself;  and  it  would  seem  as  if  slight  impressions  are  only  felt 
in  the  latter  situation,  at  least  in  the  normal  condition  of  the  trunk  or  fibre. 
Thus,  as  it  has  been  well  remarked  by  Volkmann,  "  if  a  needle's  point  be  drawn 
in  a  straight  line  across  the  back,  or  the  thigh,  or  any  part  in  which  the  nerves 
are  widely  placed,  the  mind  perceives  the  line  of  irritation  as  a  straight  one } 
whereas,  if  it  referred  all  impressions  to  the  ends  of  irritated  fibres,  this  mode 
of  irritation  should  be  felt  in  sensations  variously  scattered  about  the  line, 
at  the  points  where  the  nerve-fibres  crossed  by  the  needle  terminate."1 

II.  The  sensation  produced  by  irritation  of  a  branch  of  the  nerve  is  confined 
to  the  parts  to  which  that  branch  is  distributed,  and  does  not  affect  the  branches 
which  come  off  from  the  nerve  higher  up.  The  rationale  of  this  law  is  at  once 
intelligible  :  but  it  should  be  mentioned  that  there  are  certain  conditions,  in 
which  the  irritation  of  a  single  nerve  will  give  rise  to  sensations  over  a  great 
extent  of  the  body.  This  "radiation  of  sensations"  seems  rather  due,  however, 
to  a  particular  state  of  the  central  organs,  than  to  any  direct  communication 
among  the  sensory  fibres. 

in.  The  motor  influence  is  propagated  only  in  a  centrifugal  direction,  never  in 
a  retrograde  course.  It  may  originate  in  a  spontaneous  change  in  the  central 
organs,  or  it  may  be  excited  by  an  impression  conveyed  to  them  through  afferent 
nerves,  but  in  both  cases  its  law  is  the  same. 

IV.  When  the  whole  trunk  of  a  motor  nerve  is  irritated,  all  the  muscles  which 
it  supplies  are  caused  to  contract.  This  contraction  evidently  results  from  the 
similarity  between  the  effect  of  an  artificial  stimulus  applied  to  the  trunk  in  its 
course,  and  that  of  the  change  in  the  central  organs  by  which  the  motor  influence 
is  ordinarily  propagated.  But  when  only  a  part  of  the  trunk  or  a  branch  is 
irritated,  the  contraction  is  usually  confined  to  the  muscles  which  receive  their 
nervous  fibres  from  it ;  in  this  instance,  as  in  the  other,  there  is  no  lateral 
communication  between  the  fibrils.  An  exception  exists,  however,  in  regard 
to  galvanic  irritation,  which  may  be  transmitted  laterally  when  its  ordinary 
course  is  checked ;  as  has  been  shown  by  the  following  ingenious  experiment 
of  M.  du  Bois-Reymond.  If  any  motor  nerve  be  selected  which  divari- 
cates into  two  branches  (as,  for  example,  the  sciatic  nerve  of  a  frog,  which 
divides  above  the  bend  of  the  knee  into  the  tibial  and  peroneal  branches),  and 
a  galvanic  stimulus  be  applied  to  either  of  these  branches,  this  having  been  first 
divided  above  its  insertion  into  the  muscles,  the  electrotonic  state  will  be 
developed,  not  merely  in  the  portion  of  the  trunk  continuous  with  that  branch, 

1  "  Kirkes  and  Paget's  Handbook  of  Physiology,"  p.  375. — It  does  not  seem  improba- 
ble, however,  that  in  the  case  of  the  compression  or  other  irritation  of  a  large  nerve-trunk 
the  local  pain  may  be  produced  through  the  instrumentality  of  nervi  nervorum,  the  exist- 
ence of  which  is  scarcely  less  probable  than  that  of  vasa  vasorum. 


654  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

but  also  in  that  which  is  continuous  with  the  other  branch,  as  will  be  made 
apparent  by  the  contraction  in  the  muscles  supplied  by  the  latter.  That  this 
experiment  may  be  free  from  the  possible  fallacy  resulting  from  the  excitement 
of  reflex  action,  the  trunk  of  the  sciatic  nerve  should  be  divided  high  up,  or  the 
spinal  cord  be  destroyed. 

690.  Various  methods  of  determining  the  functions  of  particular  nerves 
present  themselves  to  the  Physiological  inquirer. — One  source  of  evidence  is 
drawn  from  their  peripheral  distribution.  For  example,  if  a  nervous  trunk  is 
found  to  lose  itself  entirely  in  the  substance  of  Muscles,  it  may  be  inferred  to 
be  chiefly,  if  not  entirely,  motor  or  efferent.  In  this  manner,  Willis  long  ago 
determined  that  the  Third,  Fourth,  Sixth,  Portio  dura  of  the  Seventh  and  Ninth 
cranial  nerves,  are  almost  entirely  subservient  to  muscular  movement ;  and  the 
same  had  been  observed  of  the  fibres  proceeding  from  the  small  root  of  the 
Fifth  pair,  before  Sir  C.  Bell  experimentally  determined  the  double  function 
of  that  division  of  the  nerve  into  which  alone  it  enters.  Again,  where  a  nerve 
passes  through  the  muscles,  with  little  or  no  ramification  among  them,  and 
proceeds  to  a  Cutaneous  or  Mucous  surface,  on  which  its  branches  are  minutely 
distributed,  there  is  equal  reason  to  believe  that  it  is  of  a  sensory,  or  rather  of 
an  afferent  j  character.  In  this  manner,  Willis  came  to  the  conclusion  that  the 
Fifth  pair  of  cranial  nerves  differs  from  those  previously  mentioned,  in  being 
partly  sensory.  Further,  where  a  nerve  is  entirely  distributed  upon  a  surface 
adapted  to  receive  impressions  of  a  special  kind,  as  the  Schneiderian  membrane, 
the  retina,  or  the  membrane  lining  the  internal  ear,  it  may  be  inferred  that  it 
is  not  capable  of  transmitting  any  other  kind  of  impressions;  for  experiment 
has  shown  that  the  special  sensory  nerves  do  not  possess  common  sensibility. 
The  case  is  different,  however,  in  regard  to  the  sense  of  taste,  which  originates 
in  impressions  not  far  removed  from  those  of  ordinary  touch ;  and  it  is  probable 
that  the  same  nerves  minister  to  both. — Anatomical  evidence  of  this  kind  is 
valuable  also,  not  only  in  reference  to  the  functions  of  a  principal  trunk,  but 
even  as  to  those  of  its  several  branches,  which,  in  some  instances,  differ  con- 
siderably. Thus,  some  of  the  branches  of  the  Pneumogastric  are  especially 
motor,  and  others  almost  exclusively  afferent;  and  anatomical  examination, 
carefully  prosecuted,  not  only  assigns  the  reasons  for  these  functions  when 
ascertained,  but  is  in  itself  nearly  sufficient  to  determine  them.  For  the  supe- 
rior laryngeal  branch  is  distributed  almost  entirely  upon  the  mucous  surface  of 
the  larynx,  the  only  muscle  it  supplies  being  the  crico-thyroid;  whilst  the 
inferior  laryngeal  or  recurrent  is  almost  exclusively  distributed  to  the  muscles. 
From  this  we  might  infer  that  the  former  is  an  afferent,  and  the  latter  a  motor 
nerve;  and  experimental  inquiries  (as  we  have  seen,  §  558)  fully  confirm  this 
view.  In  like  manner,  it  may  be  shown  that  the  Glosso-pharyngeal  is  chiefly 
an  afferent  nerve,  since  it  is  distributed  to  the  surface  of  the  tongue  and  pharynx, 
and  scarcely  at  all  to  the  muscles  of  those  parts ;  whilst  the  pharyngeal  branches 
of  the  Pneumogastric  are  chiefly,  if  not  entirely,  motor  (§  427).  Lower  down,  how- 
ever, the  branches  of  the  Glosso-pharyngeal  cease,  and  the  oesophageal  branches 
of  the  Pneumogastric  are  distributed  both  to  the  mucous  surface  and  to  the 
muscles,  from  which  it  may  be  inferred  that  they  are  both  afferent  and  motor; 
a  deduction  which  experiment  confirms  (§  428). — We  perceive,  therefore,  that 
much  knowledge  of  the  function  of  a  nerve  may  be  obtained,  from  the  attentive 
study  of  its  ultimate  distribution;  but  it  is  necessary  that  this  should  be  very 
carefully  ascertained  before  it  is  made  to  serve  as  the  foundation  for  physiological 
inferences.  As  an  example  of  former  errors  in  this  respect,  may  be  mentioned 
the  description  of  the  Portio  dura  of  the  Seventh,  at  first  given  by  Sir  C.  Bell ; 
he  stated  it  to  be  distributed  to  the  skin  as  well  as  to  the  muscles  of  the  face, 
uLd  evidently  regarded  it  as  in  part  an  afferent  nerve,  subservient  to  respiratory 


GENERAL   SUMMARY.  655 

impressions  as  well  as  to  motions.  In  the  same  manner,  from  inaccurate 
observation  of  the  ultimate  distribution  of  the  Superior  Laryngeal  nerve,  it 
was  long  regarded  as  that  which  stimulated  to  action  the  constrictors  of  the 
glottis. 

691.  But  the  knowledge  obtained  by  such  anatomical  examinations  alone 
is  of  a  very  general  kind;  and  requires  to  be  made  particular — to  be  corrected 
and  modified — by  other  sources  of  information.     One  of  these  relates  to  the 
connection  of  the  trunks  with  the  central  organs.     The  evidence  derived  from  this 
source,  however,  is  seldom  of  a  very  definite  character;  and,  in  fact,  Physiolo- 
gists have  rather  been  accustomed  to  judge  of  the  functions  of  particular  divi- 
sions of  the  nervous  centres  by  those  of  the  nerves  with  which  they  are  connected, 
than  to  draw  aid  from  the  former  in  the  determination  of  the  latter.     Still,  this 
kind  of  examination  is  not  without  its  use,  when  there  is  reason  to  believe  that 
a  particular  tract  of  fibrous  structure  has  a  certain  function,  and  when  the  office 
of  a  nerve  whose  roots  terminate  in  it  is  doubtful.     Here,  again,  however,  very 
minute  and  accurate  examination  is  necessary,  before  any  sound  physiological 
inferences  can  be  drawn  from  facts  of  this  description;  and  many  instances 
might  be  adduced  to  show  that  the  real  connections  of  nerves  and  nervous  cen- 
tres are  often  very  different  from  their  apparent  ones. 

692.  Most  important  information  as  to  the  functions  of  particular  nerves  may 
be  drawn  from  experimental  inquiries;  but  these  also  are  liable  to  give  falla- 
cious results,  unless  they  are  prosecuted  with  a  full  knowledge  of  all  the  precau- 
tions necessary  to  insure  success.     Some  of  these  will  be  here  explained. — In 
the  first  place,  the  endowments  of  the  trunk  and  of  the  roots  of  a  nerve  may 
differ;  owing  to  the  admixture,  in  the  former,  of  fibres  derived  by  inosculation 
from  another  nerve  (§  688).      Hence,  in  order  to  attain  satisfactory  results,  a 
comparative  set  of  experiments  should  always  be  made  upon  each. — A  nerve- 
trunk  may  be  too  hastily  considered  as  motor,  on  account  of  the  excitation  of 
muscular  movements  by  irritation  of  its  trunk,  whilst  still  in  connection  with  its 
centre;  for  such  movements  may  be  called  forth,  not  only  by  the  direct  influence 
of  the  nerve  upon  the  muscles,  but  also  by  reflex  stimulation,  acting  through  the 
ganglionic  centre  upon  some  other  nerve.     The  real  nature  of  such  movements 
can  only  be  determined  by  dividing  the  trunk,  and  irritating  each  of  the  cut 
extremities.     If,  upon  irritating  the  end  separated  from  the  centre,  muscular 
contractions  are  produced,  it  may  be  safely  inferred  that  the  nerve  is,  in  part  at 
least,  of  an  efferent  character.     Should  no  such  result  follow,  this  would  be 
improbable.     If,  on  the  other  hand,  muscular  movement  should  be  produced  by 
irritating  the  extremity  in  connection  with  the  centre,  it  will  then  be  evident, 
that  it  is   occasioned  by  an  impression  conveyed    towards  the   centre  by  this 
trunk,  and  propagated  to  the  muscles  by  some  other;  in  other  words,  to  use 
the  language  of  Dr.  M.  Hall,  this  nerve  is  an  "  excitor"  of  motion,  not  a  direct 
motor  nerve.     The  Grlosso-pharyngeal  has  been  satisfactorily  determined,  by 
experiments  of  this  kind,  performed  by  Dr.  J.  Reid  (§  427),  to  be  chiefly,  if  not 
entirely,  an  afferent  nerve. — It  has  been  from  the  want  of  a  proper  mode   of 
experimenting  that  the  functions  of  the  posterior  roots  of  the  Spinal  nerves 
have  been  regarded  as  in  any  degree  motor.     If  they  be  irritated,  without  divi- 
sion of  either  root,  motions  are  often  excited ;  but  if  they  be  divided,  and  their 
separated  trunks  be  then  irritated,  no  motions  ensue;  nor  are  any  movements 
produced  by  irritation  of  the  roots  in  connection  with  the  spinal  cord,  if  the  ' 
anterior  roots  have  been  divided.     Hence  it  appears  that  these  fibres  do  not 
possess  any  direct  motor  powers,  but  that  they  convey  impressions  to  the  cen- 
tre, which  are  reflected  to  the  muscles  through  the   anterior  roots. — The  same 
difficulties  do  not  attend  the  determination  of  the  sensory  endowments  of  nerves. 
If,  when  the  trunk  of  a  nerve  is  pricked  or  pinched,  the  animal  exhibit  signs 


656  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

of  pain,  it  may  be  concluded  that  the  nerve  is  capable  of  receiving  and  trans- 
mitting sensory  impressions  from  its  peripheral  extremity.  But  not  unfre- 
quently  this  capability  is  derived  by  inosculation  with  another  nerve;  as  is  the 
case  with  the  Facial,  which  is  sensory  after  it  has  passed  through  the  parotid 
gland,  having  received  there  a  twig  from  the  Fifth  pair.  A  similar  inoscula- 
tion explains  the  apparent  sensibility  of  the  anterior  roots  of  the  Spinal  nerves. 
If  these  be  irritated,  the  animal  usually  gives  signs  of  uneasiness;  but,  if  they 
be  divided,  and  the  cut  ends  nearest  the  centre  be  irritated,  none  such  are 
exhibited;  whilst  they  are  still  shown  when  the  farther  ends  are  irritated,  but 
not  if  the  posterior  roots  are  divided.  This  seems  to  indicate  that,  from  the 
point  of  junction  of  the  two  roots,  sensory  fibres  derived  from  the  posterior  root 
pass  backwards  (or  towards  the  centre)  in  the  anterior;  and  thus  its  apparent 
sensory  endowments  are  entirely  dependent  upon  its  connection  with  the  pos- 
terior column  of  the  spinal  cord,  through  the  posterior  roots. 

693.  The  fallacies  to  which   all  experiments  upon  the  nerves  are  subject, 
arising  from  the  partial  loss  of  their  power  of  receiving  and  conveying  impres- 
sions, and  of  exciting  the  muscles  to  action,  after  death,  are  too  obvious  to 
require  more  particular  mention  here;  yet  they  are  frequently  overlooked.     Of 
a  similar  description  are  those  arising  from  severe  disturbance  of  the  system,  in 
consequence  of  operations ;  which  also  have  not  been  enough  regarded  by  expe- 
rimenters.    As  a  general  rule,  negative  results  are  of  less  value  than  positive; 
but  very  careful  discrimination  is  often  required  to  determine  what  are  negative, 
and  what  positive  results.     Each  particular  case  has  its  own  sources  of  fallacy, 
which  require   to  be  logically  scrutinized ;  and  the  only  satisfactory  proof  is 
derived  from  the  concurrence  of  every  kind  of  evidence,  which  the  nature  of 
the  inquiry  admits  of.     Thus,  in  the  determination  of  the  functions  of  a  parti- 
cular nerve-trunk,  it  should  be  shown  that  a  certain  effect  is  constantly  produced 
by  its  excitation  (under  the  conditions  laid  down  in  the  preceding  paragraph), 
and  that  a  corresponding  interruption  in  the  action  to  which  it  is  hence  inferred 
to  be  subservient,  takes  place  when  its  continuity  has  been  interrupted :  by  this 
double  proof,  the  Glosso-pharyngeal  and  the  Pneumogastric  are  shown  to  be  the 
principal,  but  not  the  sole,  exciters  of  the  movements  of  Deglutition  and  Inspi- 
ration respectively.     But  the  evidence  afforded  solely  by  the  interruption  of  a 
particular  function,  after  the  division  of  a  certain  nerve,  or  the  destruction  or 
removal  of  a  nervous  centre,  is  by  no  means  so  satisfactory;  for  this  may  be 
occasioned  rather  by  the  general  effects  of  the  operation  than  by  the  simple 
lesion  of  the  nervous  apparatus.     In  order  to  get  rid,  so  far  as  possible,  of  this 
source  of  fallacy  (which  particularly  affects  experiments  upon  the  Encephalic 
centres,  and  upon  the  influence  of  the  nerves  upon  the  viscera),  it  is  desirable 
to  perform  comparative  experiments,  in  which  the  general  injury  shall  be  as 
nearly  as  possible  the  same,  and  the  only  difference  shall  lie  in  the  lesion  of  the 
nervous  system ;  and  to  subtract  from  the  general  result  all  that  can  be  thus 
shown  to  be  attributable  to  the  general  disturbance  produced  by  the  operation. 
But,  even  then,  it  may  happen  that  the  function  is  only  suspended  for  a  time 
by  the  shock  which  has  been  induced  by  the  injury  to  the  nerve ;  and  if  it 
should  be  subsequently  renewed,  without  any  reunion  of  the  trunk,  we  have  the 
most  convincing  proof  that,  whatever  degree  of  participation  the  nerve  may  have 
in  it,  the  action  is  not  essentially  dependent  upon  the  integrity  of  that  portion 
of  the  nervous  apparatus.       Such  we  have  seen  to  be  the  case  in  regard  to  the 
relation  of  the  Pneumogastric  nerves  to  the  secretion  of  gastric  fluid  in  the  walls 
of  the  stomach  (§§  445-447). 

694.  All  our  positive  knowledge  of  the  functions  of  the  Nervous  System  in 
general,  save  that  which  results  from  our  own   consciousness  of  what  passes 
within  ourselves,  and  that  which  we  obtain  from  watching  the  manifestations  of 


GENERAL    SUMMARY.  657 

disease  in  Man,  is  derived  from  observation  of  the  phenomena  exhibited  by 
animals  made  the  subjects  of  experiments;  and  in  the  interpretation  of  these, 
great  caution  must  be  exercised. — In  the  first  place  it  must  be  constantly  borne 
in  mind  that,  except  through  the  movements  consequent  upon  them,  we  have  no 
means  of  ascertaining  whether  or  not  particular  changes  in  the  Nervous  System, 
whose  character  we  are  endeavoring  to  determine,  are  attended  with  Sensation ; 
since  we  have  no  power  of  judging  whether  or  not  this  has  been  excited,  save 
by  the  cries  and  struggles  of  the  animal  made  the  subject  of  experiment.  Now 
although  such  cries  and  struggles  are  ordinarily  considered  as  indications  of 
pain,  yet  it  is  not  right  so  to  regard  them  in  every  instance ;  and  the  only 
unequivocal  evidence  is  derived  from  observation  of  the  corresponding  phenomena 
in  the  Human  subject :  since  we  can  there  ascertain,  by  the  direct  testimony  of 
the  individual  affected,  what  impressions  produce  sensation,  and  what  excite 
movements  independently  of  sensation  (§  674).  Further,  we  are  not  justified  in 
assuming  that  Consciousness  is  excited  by  an  irritation,  still  less  that  Intelli- 
gence and  Will  are  called  into  exercise  by  it,  merely  because  movements, 
evidently  tending  to  get  rid  of  its  source,  are  performed  in  respondence  to  it. 
We  know  that  the  contractions  of  the  heart  and  alimentary  tube  are  ordinarily 
excited  by  a  stimulus,  without  any  sensation  being  involved ;  and  these  move- 
ments, like  all  that  are  concerned  in  the  maintenance  of  the  Organic  functions, 
have  an  obvious  design,  when  considered  either  in  their  immediate  effects,  or  in 
their  more  remote  consequences.  The  character  of  adaptiveness,  then,  in 
Muscular  movements  excited  by  external  stimuli,  is  no  proof  that  they  are 
performed  in  obedience  to  sensation;  much  less,  that  they  have  a  voluntary 
character.  In  no  case  is  this  adaptiveness  more  remarkable  than  in  some  of 
those  actions  which  are  not  only  performed  without  any  effort  of  the  will,  but 
which  the  will  cannot  imitate.  This  is  the  case,  for  example,  with  the  act  of 
Deglutition  (§§  427,  428),  the  muscles  concerned  in  which  cannot  be  thrown 
into  contraction  by  a  voluntary  impulse,  being  stimulated  only  by  impressions 
conveyed  from  the  mucous  surface  of  the  'fauces  to  the  Medulla  Oblongata,  and 
thence  reflected  along  the  motor  nerves.  No  one  can  swallow,  without  producing 
an  impression  of  some  kind  upon  this  surface,  to  which  the  muscular  movements 
will  immediately  respond.  Now  it  is  impossible  to  conceive  any  movements 
more  perfectly  adapted  to  a  given  purpose,  than  those  of  the  parts  in  question ; 
and  yet  they  are  independent  not  only  of  volition  but  of  sensation,  being  still 
performed  in  cases,  in  which  consciousness  is  completely  suspended,  or  entirely 
absent.  The  act  of  Sucking  in  the  infant,  again,  is  one  in  which  a  number  of 
muscles  are  called  into  combined  contraction,  in  a  manner  which  shows  a  most 
complete  adaptation  to  a  given  purpose ;  &nd  yet  it  is  impossible  to  suppose 
this  adaptation  to  be  purposive  on  the  part  of  the  infant  itself ;  more  especially 
as  it  is  shown,  both  by  the  occurrence  of  monstrosities,  and  by  experiments 
made  with  this  object  (§  423),  that  no  part  of  the  Cranio-spinal  axis  above  the 
Medulla  Oblongata  is  necessary  to  it.  And  in  the  acts  of  Coughing  and 
Sneezing  (§  555),  we  have  examples  of  the  most  adaptive  movements,  executed 
by  a  marvellous  combination  of  separate  muscular  actions,  with  the  obvious 
purpose  of  removing  a  source  of  irritation  from  the  air-passages ;  and  yet  we 
know  by  personal  experience,  that  this  combination  is  not  made  with  any  design 
of  our  own. 

695.  In  addition  to  the  Cerebro-Spinal  system  of  ganglionic  centres  and 
nerve-trunks,  all  but  the  lowest  Vertebrated  animals  possess  a  system  of 
ganglionic  centres  scattered  in  different  parts  of  the  body,  but  mutually  con- 
nected with  each  other,  as  well  as  with  the  Cerebro-spinal  system ;  this  is  com- 
monly termed  the  Sympathetic  system;  but  not  unfrequently,  from  the 
position  of  its  principal  centres,  and  their  evident  functional  relation  to  the 
42 


658 


OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 


Fig.  172. 


apparatus  of  Organic  life,  the 
Visceral  system.  To  this  system, 
which  seldom  presents  itself  in  a 
distinctly  recognizable  form  in  In- 
vertebrated  animals,  we  are  pro- 
bably to  refer  not  only  the  Semi- 
lunar  and  Cardiac  ganglia  (which 
seem  to  be  its  principal  centres), 
with  the  chain  of  cranial,  cervical, 
thoracic,  lumbar,  and  sacral  gan- 
glia, which  are  in  nearer  connection 
with  the  cerebro-spinal  system,  but 
also  numerous  minute  ganglia,  which 
are  to  be  found  on  its  branches  in 
various  parts,  and,  in  addition,  the 
ganglia  upon  the  posterior  roots  of 
the  spinal  nerves ;  and  if  such  be 
the  case,  those  fibres  contained  in 
the  cerebro-spinal  nerves,  which 
have  these  as  their  ganglionic  cen- 
tres, must  also  be  accounted  as 
belonging  to  the  Sympathetic  sys- 
tem. On  the  other  hand,  there  un- 
questionably exist  numerous  fibres 
in  the  Visceral  system,  which  pro- 
ceed into  it  from  the  Cerebro-spinal 
system;  these,  however,  are  not 
uniformly  distributed,  for  some  of 
the  Visceral  nerves  contain  few  or 
none  of  them,  whilst  in  others 
they  are  numerous.  The  branches 
by  which  the  Sympathetic  system 
communicates  with  the  Cerebro- 
spinal,  and  which  were  formerly 
considered  as  the  roots  of  the  Sym- 
pathetic system,  contain  fibres  of 
both  kinds; — i.  e.,  Cerebro-spinal 
fibres  passing  into  the  Sympathetic, 
and  Sympathetic  fibres  passing  into 
the  Cerebro-spinal.  The  latter  are 
chiefly,  if  not  entirely,  transmit- 
ted into  the  anterior  branches  of 
the  Spinal  nerves;  the  posterior 

A  view  of  the  Great  Sympathetic  Nerve. — 1,  the  plexus  on  the  carotid  artery  in  the  carotid  foramen ;  2, 
«ixth  nerve  (motor  externus) ;  3,  first  branch  of  the  fifth  or  ophthalmic  nerve ;  4,  a  branch  on  the  septum 
narium  going  to  the  incisive  foramen ;  5.  the  recurrent  branch  or  vidian  nerve  dividing  into  the  carotid  and 
petrosal  branches;  6,  posterior  palatine  branches;  7,  the  lingual  nerve  joined  by  the  chorda  tympani;  8,  the 
portio  dura  of  the  seventh  pair  or  the  facial  nerve;  9,  the  superior  cervical  ganglion ;  10,  the  middle  cervical 
ganglion;  11,  the  inferior  cervical  ganglion ;  12,  the  roots  of  the  great  splanchnic  nerve  arising  from  the  dorsal 
ganglia;  13,  the  lesser  splanchnic  nerve;  14,  the  renal  plexus;  15,  the  solar  plexus;  16,  the  mesenteric 
plexus;  17,  the  lumbar  ganglia;  18,  the  sacral  ganglia;  19,  the  vesical  plexus;  20,  the  rectal  plexus;  21,  the 
lumbar  plexus  (cerebro-spinal);  22,  the  rectum;  23,  the  bladder;  24,  the  pubis;  25,  the  crest  of  the  ilium; 
26,  the  kidney;  27,  the  aorta;  28,  the  diaphragm  ;  29,  the  heart;  30,  the  larynx ;  31,  the  subiuaxillary  gland; 
32,  the  incisor  teeth;  33,  nasal  septum ;  34,  globe  of  the  eye ;  35,  36,  cavity  of  the  cranium. 


THE   SPINAL  CORD. 


659 


branches  being  apparently  supplied  FlS-  173- 

with  sympathetic  fibres  from  the 
ganglia  on  their  own  posterior  roots. 
Some  of  these  last  fibres  also  pass 
from  the  cerebro-spinal  into  the 
Sympathetic  system.  By  these 
communications,  the  two  systems 
of  fibres  are  so  blended  with  each 
other,  that  it  is  impossible  to  isolate 
them. — The  branches  proceeding 
from  the  Semilunar  ganglia  are 
distributed  upon  the  abdominal 
viscera;  and  those  of  the  Cardiac 
ganglia  upon  the  heart  and  the 
vessels  proceeding  from  it.  The 
latter  seem  to  accompany  the  arte- 
rial trunks  through  their  whole 
course,  ramifying  minutely  upon 
their  surface;  and  it  can  scarcely 
be  doubted  that  they  exercise  an 
important  influence  over  their  func- 
tions. What  the  nature  of  that 
influence  may  be,  however,  will  be 
a  subject  for  future  inquiry.  It  is 
so  evidently  connected  with  the  ope- 
rations of  nutrition,  secretion,  &c., 
that  the  designation  of  "  nervous 
system  of  organic  life,"  as  applied 
to  this  system,  does  not  seem  objec- 
tionable, provided  that  we  do  not 
understand  it  as  denoting  the  de- 
pendence of  these  functions  upon  it. 
— Even  in  Vertebrata,  however,  we 

do  not  always  find  the  distribution  of  the  visceral  trunks  distinct  from  that  of 
the  cerebro-spinal.  In  the  Cyclostome  Fishes,  the  par  vagum  supplies  the 
intestinal  canal  along  its  whole  length,  as  well  as  the  heart;  and  no  appearance 
of  a  distinct  sympathetic  can  be  discovered.  In  Serpents,  again,  the  lower  part 
of  the  alimentary  canal  is  supplied  from  the  spinal  cord,  and  the  upper  part  by 
the  par  vagum ;  and  though  the  lateral  cords  of  the  sympathetic  may  be  traced, 
they  are  almost  destitute  of  ganglia.  Even  in  the  highest  Yertebrata,  some  of 
the  glands,  of  which  the  secretion  is  most  directly  influenced  by  the  condition 
of  the  mind,  are  supplied  with  most  of  their  nerves  from  the  cerebro-spinal 
system ;  thus,  the  lachrymal  and  sublingual  glands  receive  large  branches  from 
the  fifth  pair,  and  the  mammary  glands  from  the  intercostal  nerves. 

2.    Of  the  Spinal  Cord  and  Medulla  Oblongata ; — their  Structure  and 

Actions. 

696.  In  our  more  detailed  consideration  of  the  functions  of  the  several  divi- 
sions of  the  Nervous  System,  it  is  desirable,  for  several  reasons,  to  commence 
with  the  Cranio- Spinal  Axis;  which,  as  already  pointed  out  (§  678),  may  be 
considered  as  constituting  the  fundamental  portion  of  this  apparatus.  The  en- 
tire Axis  is  divided  into  its  Cranial  and  its  Spinal  portions,  the  passage  of  the 
Cord  through  the  foramen  magnum  of  the  occipital  bone  being  considered 


Roots  of  a  dorsal  spinal  nerve,  and  its  union  with 
sympathetic :  c,  c.  Anterior  fissure  of  the  spinal  cord.  a. 
Anterior  root.  p.  Posterior  root,  with  its  ganglion,  a'. 
Anterior  branch,  p'.  Posterior  branch,  s.  Sympathetic. 
e.  Its  double  junction  with  the  anterior  branch  of  the 
spinal  nerve  by  a  white  and  a  gray  filament. 


660  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

to  mark  the  boundary  between  them;  and  although  the  separation  of  the 
Medulla  Spinalis  from  the  Medulla  Oblongata  which  is  thus  established, 
is  in  itself  purely  artificial,  yet  it  will  be  found  to  correspond  completely 
with  the  natural  division  founded  on  their  respective  physiological  attributes. 
The  Spinal  Cord*  then,  which  extends  from  the  margin  of  the  foramen 
magnum  to  the  first  or  second  lumbar  vertebra,  and  which  is  prolonged  as 
thefilum  terminale*  to  the  extremity  of  the  sacral  canal,  is  almost  completely 
divided  by  the  anterior  and  posterior  median  fissures  (Fig.  174),  into  two 
lateral  and  symmetrical  halves.  The  "anterior  median  fissure"  (a)  is  more 
distinct  than  the  posterior,  being  wider  at  the  surface ;  but  it  only  pene- 
trates to  about  one-third  of  the  thickness  of  the  Cord,  its  depth  increasing,  how- 
ever, towards  its  lower  part.  The  sides  of  the  "  posterior  median  fissure"  (p), 
on  the  other  hand,  are  in  closer  approximation  ;  but  the  division  commonly  ex- 
tends to  about  half  the  thickness  of  the  cord,  being  deeper  towards  its  upper 
than  towards  its  lower  end.  The  two  halves,  therefore,  are  only  united  by  a 
commissural  band  which  occupies  the  central  part  of  the  cord,  and  this  is 
traversed  by  the  "  Spinal  canal"  (/),  which  is  continued  downwards  from 
the  fourth  ventricle.3  At  a  little  distance  from  either  side  of  the  posterior 
median  fissure,  and  corresponding  with  the  line  of  attachment  of  the  posterior 
roots  of  the  nerves,  is  the  posterior  lateral  furrow  ;  a  shallow,  longitudinal  de- 
pression, which  marks  out  the  "  posterior  columns"  of  the  cord  as  distinct  from 
the  "  antero-lateral  columns."  A  corresponding  furrow  has  been  sometimes 
described  as  traversing  the  Cord  in  the  line  of  the  anterior  roots  of  the  nerves 
on  either  side ;  but  this  can  scarcely  be  said  to  have  a  real  existence  ;  and  the 
separation  of  the  "antero-lateral  columns"  into  the  ts  anterior"  and  the  "  lateral" 
columns,  is  only  marked  externally  by  the  attachment  of  the  nerve-roots,  but 
is  made  more  obvious  internally  by  the  peculiar  distribution  of  the  gray  matter. 
These  columns  are  entirely  composed  of  nerve-fibres,  whose  general  direction  is 
longitudinal;  and  of  these  fibres  it  is  quite  certain  that  some  are  directly  con- 
tinuous with  those  which  constitute  the  roots  of  the  spinal  nerves.  It  has  been 
generally  considered  by  Anatomists,  that  the  anterior  roots  are  chiefly  connected 
with  the  anterior  columns,  but  that  some  of  their  fibres  are  also  continuous  with 
the  lateral  columns;  and  that  the  posterior  roots  are  in  like  manner  connected 
chiefly  with  the  posterior,  but  also  with  the  lateral  columns.  Some  have  main- 
tained, on  the  other  hand,  that  both  sets  of  nerve-roots  are  connected  with  the 
lateral  columns  exclusively.  According  to  the  most  recent  researches,  however, 
it  appears  that  the  anterior  roots  are  directly  connected  with  the  anterior  columns 
only,  and  the  posterior  roots  with  the  posterior  columns  alone ;  but  of  those 
fibres  from  both  these  roots  which  pass  at  first  into  the  gray  matter,  a  certain 
proportion  emerge  from  this  and  enter  the  lateral  columns. — To  what  extent 
any  of  these  fibres  proceed  along  the  columns  of  the  Spinal  Cord,  no  precise 
anatomical  evidence  has  yet  been  obtained ;  and  although  there  are  appearances 
which  may  be  regarded  as  sanctioning  the  idea  that  a  direct  and  continuous 
communication  is  established  by  their  means  between  the  roots  of  the  nerves 

1  The  sketch  given  in  the  text  of  the  anatomy  of  the  Spinal  Cord  is  chiefly  derived  from  the 
statements  of  Prof.  Kolliker  in  his  "Mikroskopische  Anatomic"  (Band  ii.  \\  115,  116),  and 
of  Mr.  J.  L.  Clarke  in  the  "Philosophical  Transactions,"  1851 ;  between  which  there  is  a 
general  accordance. 

2  The  structure  of  the  "  filum  terminate"  is  in  every  respect  essentially  the  same  as  that 
of  the  proper  Spinal  Cord,  save  that  no  nerve-roots  are  connected  with  it. 

3  The  spinal  canal  is  much  more  obvious  in  Fishes ;  and  the  commissural  connection  be- 
tween the  two  halves  of  their  spinal  cord  is  far  less  distinct  than  in  higher  Vertebrata.     The 
canal  can  only  be  distinguished  in  Man,  being  no  more  than  l-100th  of  an  inch  in  diameter, 
by  submitting  thin  transverse  sections  of  the  Cord  to  microscopic  examination. 


THE    SPINAL   CORD. 


661 


and  the  encephalic  centres,  yet  there  are  difficulties,  in  such  a  view  of  the  case, 
which  must  be  taken  into  account  in  our  physiological  consideration  of  it  (§  700). 
697.  The  "  gray  matter"  of  the  Spinal  Cord  is  readily  brought  into  view  by 
making  transverse  sections  in  different  parts :  and  although  its  distribution  is 
by  no  means  uniform,  yet  on  the  whole  it  may  be  described  as  constituting 
(when  thus  exposed)  two  somewhat  crescent-shaped  masses  (Fig.  174),  whose 
convexities  are  turned  towards  each  other,  and  are  connected  by  the  gray  com- 
missure, whilst  their  cornua  are  directed  towards  the  surface  of  the  cord ;  the 
posterior  peak  on  either  side  reaching  the  posterior  lateral  furrow,  whilst  the 
anterior,  though  the  larger  cornu,  does  not  approach  quite  so  near  to  the  surface. 
This  gray  matter,  however,  is  by  no  means  uniform  in  its  texture  throughout. 
A  considerable  part  of  the  posterior  cornua  is  destitute  of  vesicular  or  gangli- 
onic  corpuscles,  and  is  known  under  the  name  of  substantia  gelatinosa  (</)  j  it 
has  been  lately  shown  by  Mr.  J.  L.  Clarke,  however,  that  a  tract  of  vesicular 
matter  does  exist  on  either  side  (e),  in  intimate  connection  with  the  posterior 
roots  of  the  nerves,  and  that  this  may  be  traced  continuously  from  the  lower 
extremity  of  the  spinal  cord  to  the  medulla  oblongata  where  it  terminates,  and 
that  it  increases  in  size  in  the  lumbar  and  cervical  enlargements.  The  gray 
matter  of  the  anterior  cornua,  which  has  been  distinguished  as  the  substantia 
spongiosa,  contains  a  large  amount  of  vesicular  structure  (d,  cT),  the  number  of 


Transverse  section  of  Human  Spinal  Oord,  through  the  middle  of  the  lumbar  enlargement,  showing  on  the 
right  side  the  course  of  the  nerve-roots,  and  on  the  left  the  position  of  the  principal  tracts  of  vesicular  mat- 
ter :  A,  A,  anterior  columns ;  p,  P,  posterior  columns ;  L,  L,  portion  of  lateral  columns ;  a,  anterior  median 
fissure ;  p,  posterior  median  fissure  ;  b,  b,  b,  b,  anterior  roots  of  spinal  nerves ;  c,  c,  posterior  roots ;  d,  d,  tracts 
of  vesicular  matter  in  anterior  column ;  e,  tracts  of  vesicular  matter  in  posterior  column ;  f,  spinal  canal ;  g, 
substantia  gelatinosa. 

vesicles  being  constantly  in  direct  proportion  to  the  size  of  the  nerve-roots  in 
connection  with  it.  The  vesicles  are  of  the  stellate  character,  each  having 
several  prolongations  which  seem  to  unite  with  those  of  other  vesicles;  and 


662  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

hitherto  it  has  not  been  found  possible  to  trace  any  direct  passage  of  these  prolon- 
gations into  nerve-fibres.  The  commissure  is  formed  entirely,  according  to  Mr. 
J.  L.  Clarke,  by  the  fibrous  portion  of  the  gray  matter,  neither  the  anterior  nor 
the  posterior  columns  having  any  direct  connection  by  transverse  fibres ;  and 
the  central  part  of  it  is  stated  by  him  to  consist  of  a  layer  of  fine  fibrous  tissue 
surrounding  the  wall  of  the  spinal  canal,  which  is  lined  with  a  layer  of  colum- 
nar epithelium.  The  fibres  of  the  gray  substance  and  even  those  of  the  sub- 
stantia  gelatinosa  are  tubular,  but  are  of  extremely  minute  size,  their  average 
diameter  not  exceeding  l-10,000th  of  an  inch,  and  some  of  them  measuring  as 
little  as  1-1 5,000th  or  l-16,000th.  The  course  of  the  fibres  which  constitute 
the  roots  of  the  Spinal  Nerves,  as  seen  in  transverse  sections  of  the  Cord,  is 
thus  described  by  Mr.  J.  L.  Clarke.  The  bundles  of  fibres  which  form  the  pos- 
terior root  (Fig.  174,  c,  c)  are  much  larger,  but  less  numerous  than  those  of  the 
anterior ;  the  fibres  themselves  are  mostly  finer  and  more  delicate,  their  average 
diameter  being  about  l-7000th  of  an  inch.  On  entering  the  posterior  columns 
of  the  Cord,  the  fasciculi  traverse  them  obliquely  inwards,  interlacing  and  form- 
ing with  each  other  an  intricate  plexus.  From  this  plexus,  straight  and  distinct 
bundles  enter  the  posterior  cornua  along  their  whole  breadth,  and  cross  the 
"substantia  gelatinosa"  both  obliquely  and  at  right  angles;  some  being  immedi- 
ately continuous  with  fibres  of  the  transverse  commissure,  some  passing  to  the 
vesicular  tract,  while  others  break  up  and  form  a  finer  network  which  extends 
towards  the  anterior  cornua.  Some  of  these  fibres,  after  traversing  the  gray 
substance,  pass  out  again  into  the  posterior  and  lateral  white  columns ;  and  many 
of  those  of  the  "substantia  gelatinosa"  seem  to  become  longitudinal.  The 
fasciculi  of  fibres  which  constitute  the  anterior  roots,  on  the  other  hand,  traverse 
the  anterior  columns  of  the  Cord  somewhat  obliquely,  and  in  straight  and  dis- 
tinct bundles,  which  do  not  interlace  with  each  other,  but  proceed  directly  to 
the  anterior  gray  cornu.  On  reaching  this,  they  break  up  into  smaller  bundles 
and  separate  fibres,  which  diverge  in  various  directions;  of  those  proceeding 
towards  the  external  border  of  the  cornu,  some  pass  out  again  into  the  antero- 
lateral  column,  whilst  others,  after  winding  round  groups  of  caudate  vesicles, 
curve  inwards  and  join  the  fibres  of  the  transverse  commissure ;  of  those  pro- 
ceeding along  the  inner  border  of  the  cornu,  a  few  pass  into  the  white  column 
at  the  side  of  the  median  fissure,  while  others,  entering  the  anterior  portion  of 
the  transverse  commissure,  cross  to  the  opposite  side ;  and  the  remainder,  plung- 
ing into  the  central  portion  of  the  cornu,  and  winding  among  its  vesicles,  seem 
to  lose  themselves  in  its  substance,  some  of  them  probably  changing  their  di- 
rection and  becoming  longitudinal.  According  to  Stilling,  an  absolute  con- 
tinuity is  thus  established  between  certain  of  the  anterior  and  posterior  root- 
fibres  of  the  same  side ;  and  also  between  the  anterior  fibres  of  one  side  and 
the  posterior  of  the  other,  through  the  transverse  commissure.  The  evidence 
which  he  has  adduced  in  favor  of  this  doctrine,  however,  is  by  no  means  satis- 
factory ;  and  for  the  present  it  must  be  regarded  as  hypothetical.  That  an 
actual  decussation  of  the  fibres  of  the  Cord  is  effected  by  means  of  the  trans- 
verse commissure,  although  denied  by  Hannover,  seems  to  have  been  fully 
proved  by  Mr.  J.  L.  Clarke;  this  decussation,  however,  is  limited,  as  already 
stated,  to  the  fibres  of  the  gray  matter.1 

698.  The  Spinal  Cord  is  by  no  means  of  uniform  dimensions  throughout  its 

1  Mr.  J.  L.  Clarke  has  succeeded  in  preparing  transverse  sections  of  the  Cord  of  suffi- 
cient thinness  to  enable  them  to  be  seen  under  high  powers  with  transmitted  light; 
whereas  the  statements  of  Stilling,  and  of  other  observers  who  have  used  his  method, 
have  been  founded  upon  observations  made  upon  comparatively  opaque  sections  seen  under 
low  powers,  and  often  with  reflected  light,  whereby  the  nature  of  the  several  structures 
was  often  left  in  obscurity. 


THE   SPINAL   CORD. 


663 


length,  but  presents  an  enlargement  at  the  origins  of  the  large  nerves  forming 
the  brachial  and  crural  plexuses.     This  enlargement  is 
produced  by  an  increase  in  the  quantity  both  of  the  gray  Fig.  175. 

and  of  the  white  substances;  and  it  is  obviously  compar-  ^ 

able  to  the  enlargement  of  the  ganglia  of  the  ventral  cord 
of  Articulata,  which  presents  itself  in  connection  with 
the  nerves  of  the  special  locomotive  organs,  as  we  well 
see  in  tracing  the  alterations  which  this  cord  undergoes 
between  the  "larva"  and  " imago"  states  of  the  Insect.1 
Its  relation  to  the  functions  of  these  nerves  is  further 
indicated  by  the  constancy  with  which  it  presents  itself, 
through  the  entire  Vertebrated  series,  in  those  parts  of 
the  Cord  from  which  the  largest  supply  is  transmitted  to 
the  locomotive  organs.  In  most  Fishes,  for  example,  the 
body  being  propelled  through  the  water  rather  by  the 
lateral  action  of  the  flattened  trunk  and  tail  (with  that  of 
the  median  fins),  than  by  the  movements  of  the  extremi- 
ties, which  serve  principally  to  guide  it,  the  size  of  the 
Cord  usually  varies  but  little  through  its  whole  length ; 
and  this  is  especially  the  case  with  the  Eel  and 
other  vermiform  apodal  fishes.  But  in  the  Flying-fish, 
and  others  whose  pectoral  fins  are  unusually  powerful,  a 
distinct  ganglionic  enlargement  of  the  cord  presents  itself 
where  their  nerves  are  given  off.  In  Serpents,  again, 
the  spinal  cord  is  nearly  uniform  throughout  its  entire 
length;  whilst  in  Amphibia  it  is  so  during  the  Tadpole 
condition,  but  presents  enlargements  corresponding  to  the 
anterior  and  posterior  extremities,  when  these  are  deve- 
loped; at  the  same  time  becoming  much  shortened,  as  the 
tail  is  less  important  to  locomotion,  or  is  altogether 
atrophied.  In  Birds,  the  ganglionic  enlargements  are 
generally  very  perceptible,  and  bear  a  close  relation  in 
size  with  the  development  of  the  locomotive  organs  with 
which  they  are  connected:  thus  in  birds  of  active  flight, 
and  short  powerless  legs,  the  anterior  enlargement  is 
the  principal;  but  in  those  which  are  more  adapted  to 
run  on  land  than  to  wing  their  way  through  the  air, 
such  as  the  whole  tribe  of  Struthious  birds,  the  size  of 
the  posterior  enlargement  is  very  remarkable;  and  this 
exactly  corresponds  with  what  has  been  observed  in 
the  Articulated  classes,  and  especially  in  watching  the 
metamorphosis  of  Insects.  In  Birds  and  Mammalia, 
however,  the  whole  amount  of  the  gray  matter  in  the 
spinal  cord  does  not  bear  so  large  a  proportion  to  the 
bulk  of  the  nerves  proceeding  from  it,  as  in  the  lower 
Vertebrata;  and  the  reason  of  this  seems  obvious.  The 
actions  of  the  locomotive  organs  are  less  and  less  of  a 
reflex  character,  and  are  more  directly  excited  by  the 
will,  and  consequently  by  the  brain,  than  in  the  inferior  tribes;  and  just  in 
proportion,  therefore,  to  the  development  of  the  Brain,  will  it  become  the  mov- 
ing spring  of  all  the  actions  performed  by  the  animal,  and  the  Spinal  Cord  be 
merely  its  instrument.  Still,  in  all  the  Mammalia,  as  in  Man,  do  we  find  these 


Transverse  sections  of 
the  spinal  cord :  A.  Im- 
mediately below  the  decus- 
sation  of  the  pyramids. — 
B.  At  middle  of  cervical 
bulb.  c.  Midway  between 
cervical  and  lumbar  bulbs. 
D.  Lumbar  bulb.  E.  An 
inch  lower.  F.  Very  near 
the  lower  end.  a.  Anteri- 
or surface,  p.  Posterior 
surface.  The  points  of 
emergence  of  the  anterior 
and  posterior  roots  of  the 
nerves  are  also  seen. 


See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  g  776,  Am.  Ed. 


664  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

ganglionic  enlargements  of  the  spinal  cord;  and  in  Man  it  is  the  posterior  one 
(or  rather  the  inferior),  which  contains  the  largest  quantity  of  gray  matter. 

699.  No  doubt  is  now  entertained  amongst  Physiologists  that  the  Spinal 
Cord  is  to  be  regarded  under  a  double  aspect; — on  the  one  hand,  as  an  inde- 
pendent centre  of  nervous  power,  on  which  excitor  impressions  operate  to  pro- 
duce reflex  movements; — and,  on  the  other,  as  the  channel  of  communication 
between  the  roots  of  the  spinal  nerves  and  the  encephalic  centres,  whereby 
sensory  impressions  are  transmitted  upwards  to  the  sensorium,  and  motor  influ- 
ences originating  in  the  brain  are  transmitted  downwards  to  the  efferent  nerves. 
But  with  regard  to  what  may  be  termed  the  mechanism  by  which  this  is  effected, 
there  is  at  present  a  considerable  diversity  of  opinion ;  which  arises  out  of  the 
difliculty  of  determining,  on  the  one  hand,  whether  any  of  the  root-fibres  actually 
terminate  in  the  gray  matter  of  the  Cord,  and,  on  the  other,  whether  the  longi- 
tudinal fibres  of  the  white  columns  are  actually  continuous  from  the  Medulla 
Oblongata  to  the  roots  of  the  Spinal  nerves.  Three  distinct  notions  of  this 
mechanism  at  present  have  their  several  advocates  amongst  Anatomists  of  dis- 
tinction. 

I.  According  to  the  first  view,  which  may  be  regarded  as  a  modification  of 
the  doctrine  which  was  current  before  the   independent  power  of  the    Spinal 
Cord  had  been  distinctly  recognized,  all  the  root-fibres  of  the  Spinal  nerves  are 
brought  by  means  of  its  longitudinal  columns   into  direct  continuity  with   the 
Encephalic  centres;  so  that  sensory  impressions  are  transmitted  upwards  to  the 
sensorium,  and  motor  impulses  are  transmitted  downwards  from    the  seats  of 
volition,  emotion,  &c.,  without  any  interruption.     But  these  fibres  pass  through 
the  gray  substance  of  the  Spinal  Cord,  in  their  transit  from  the  white  columns 
to  the  nerve  roots,  and  are  thus  subjected  to  the  influence  of  its  vesicular  matter, 
which  is  capable  of  exerting  an  independent  operation  through  them,  especially 
when  their  continuity  with  the  Brain  is  interrupted. 

II.  According  to  the  second  view,  the  Spinal  Cord  is  the  real  ganglionic 
centre  of  all  the  root-fibres  of  the  nerves  issuing  from  it;  each  pair  of  nerves 
being  thus  directly  connected  only  with  its  own  segment  of  the  cord,  or  with 
other  segments  a  little  above  or  below  this ;  and  the  function  of  the  white  or 
longitudinal  columns  being  to  establish  a  commissural  connection  between  the 
several  segments  of  the  Cord,  and  to  bring  them  into  connection  also  with  the 
Encephalic  centres.     On  this  hypothesis,  no  sensory  impressions  pass  directly 
from  the  Spinal  nerves  to  the  Sensorium,  and  no  motor  impulse  is    directly 
transmitted  from  any  part  of  the  Encephalon  to  these  nerves,  the   vesicular 
matter  of  the  Spinal  Cord  being  in  each  case  the  immediate  recipient  of  the 
change,  and  serving  (so  to  speak)  as  a  fresh  starting-point  for  the  nerve-force ; 
whilst,  if  the  connection  of  any  segment  with  the  Encephalon  be  interrupted, 
that  segment  reacts  upon  impressions  transmitted  to  it,  in  virtue   of  the  direct 
connection  of  the  nerve-roots  with  its  own  ganglionic  centre. 

in.  The  third  view  is  a  combination  of  both  the  preceding  doctrines;  for  it 
is  considered  by  those  who  advocate  it,  that  certain  of  the  root-fibres,  passing 
continuously  along  the  longitudinal  columns  of  the  Cord,  establish  a  direct  con- 
nection, for  sensory  and  motor  purposes,  between  the  Spinal  nerves  and  the 
Encephalic  centres ;  while  certain  other  fibres  have  their  central  termination  in 
the  gray  matter  of  the  Cord  itself.  It  is  considered,  on  this  hypothesis,  that  the 
fibres  which  minister  to  sensory  impressions  do  so  in  virtue  of  their  direct  and 
continuous  passage  from  the  peripheral  surface  to  the  sensorium;  whilst  the 
fibres  which  transmit  downwards  from  the  Encephalic  centres  the  motor  im- 
pulses originating  in  them,  pass  continuously  to  the  muscles  which  they  call  into 
play.  On  the  other  hand,  each  segment  of  the  Cord  is  considered  to  minister 
to  itsown  reflex  action;  the  different  segments,  however,  possessing  such  a 
commissural  connection  with  each  other,  that  an  impression  made  upon  one  of 


THE    SPINAL   CORD.  665 

them  may  be  transmitted  to  many  others,  and  may  excite  reflex  movements 
through  them.  Among  those  who  hold  this  view,  however,  there  is  a  very  con- 
siderable difference  of  opinion  with  regard  to  the  real  centre  of  the  Encephalic 
fibres;  some  maintaining  that  they  pass  through  the  Corpora  Striata,  Thalami 
Optici,  and  other  Sensory  Ganglia,  to  the  peripheral  vesicular  matter  of  the 
Cerebrum;  whilst  others  hold  that  the  real  termination  of  all  of  them  is  in  the 
Sensory  Ganglia,  and  that  the  Cerebrum  has  therefore  no  connection  with  them, 
otherwise  than  through  the  intermediation  of  those  bodies.  Although  this 
question  may  be  considered  as  rather  related  to  the  structure  and  functions  of 
the  Encephalic  centres,  than  to  that  of  the  Spinal  Cord,  yet  it  has  such  a  bear- 
ing upon  the  function  assigned  to  the  longitudinal  fibres  of  the  Cord  that  it 
must  be  taken  into  account  in  the  present  discussion. 

700.  The  principal  argument  for  the  doctrine  (which  seems  to  have  origi- 
nated with  the  anatomical  researches  of  Stilling  and  Wallach,1  and  to  have  been 
first  put  forth  on  a  physiological  basis  by  Messrs.  Todd  and  Bowman3)  that  the 
Spinal  Cord  is  the  real  centre  of  all  the  nerve-fibres  connected  with  it,  arises 
from  the  asserted  difficulty  of  supposing  that  its  longitudinal  columns  can  trans- 
mit any  considerable  number  of  nerve-fibres  from  the  Encephalon  to  the  Spinal 
nerve-roots.  Thus  it  is  urged  by  Dr.  Todd,  that  it  is  highly  improbable  that 
the  only  channel  by  which  the  Will  can  influence  the  spinal  nerves  should  be 
(as  generally  admitted)  that  afforded  by  the  Anterior  Pyramids;  since  the 
whole  bulk  of  these  pyramids  on  both  sides,  taken  together,  scarcely  equals  that 
of  one  of  the  anterior  portions  of  the  antero-lateral  columns.  Moreover,  if  there 
were  a  gradual  giving-off  of  Encephalic  fibres  from  the  longitudinal  columns 
into  the  roots  of  the  nerves,  the  size  of  these  columns  ought  progressively  to 
diminish  from  above  downwards;  whereas  it  is  asserted  by  Volkmann,  who  has 
strenuously  upheld  this  doctrine,3  that  the  size  of  the  white  columns  presents 
no  such  diminution,  but  that  it  is  everywhere  proportional  to  the  quantity  of 
gray  matter  in  the  Cord.  Thus  in  Serpents,  the  Spinal  cord  (as  already  no- 
ticed) is  remarkable  for  its  uniformity  of  dimension  through  its  entire  length, 
the  absence  of  limbs  preventing  the  necessity  for  an  increase  in  the  quantity  of 
gray  matter  in  any  part,  and  the  fibrous  columns  presenting  a  similar  uniformity 
throughout;  whereas,  if  the  latter  be  really  Encephalic,  they  should  gradually 
dwindle  away  from  the  head  to  the  tail.  Moreover,  it  has  been  estimated  by 
Volkmann,  that  the  area  of  the  whole  Spinal  Cord  of  a  Boa,  at  its  anterior  part, 
is  not  more  than  one-eleventh  part  of  the  united  area  of  the  221  pairs  of  nerves 
which  are  given  off  from  it.  Further,  it  is  urged  by  Volkmann,  that  the  white 
columns  are  absolutely  smaller  in  the  cervical  region  than  they  are  in  the 
lower  part  of  the  cord,  so  that  they  would  not  suffice  to  convey  even  the  lumbar 
columns  upwards  to  the  Encephalon,  much  less  to  transmit  the  fibres  of  all  the 
intervening  nerves  in  addition.  Thus,  having  weighed  four  pieces  of  a  Horse's 
spinal  cord,  all  of  the  same  length,  and  taken  respectively  from  below  the 
second,  eighth,  nineteenth,  and  thirtieth  pairs  of  nerves,  he  found  that  their 
weights  were  respectively  219,  293,  163,  and  281  grains;  and  that  the  trans- 
verse sections  of  the  gray  matter  gave  respectively  the  area  of  13,  28,  11,  and 
25  square  lines,  whilst  those  of  the  white  matter  measured  109,  142,  89,  and 
121  square  lines.  Hence  the  greatest  amount  of  fibrous  as  well  as  of  gray 
substance  is  found  in  those  enlargements  of  the  cord  which  are  the  ganglionic 
centres  of  tlie  nerves  of  the  extremities;  these  being  the  parts  from  which  the 
second  and  fourth  segments  were  taken  in  the  preceding  experiment.  On  the 
other  hand,  in  the  middle  dorsal  region,  the  amount  of  fibrous  structure  appears 

1  "  Untersuclmngen  iiber  die  Textur  des  Riickenmarks,"  Leipzig,  1842. 

2  "Physiological  Anatomy  and  Physiology  of  Man,"  Am.  Ed. 

3  See  his  valuable  article  "  Nervenphysiologie,"  in  Wagner's  "  Handworterbuch   der 
Physiologic." 


666  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

reduced  to  its  minimum;  and  in  the  upper  cervical  region  it  is  considerably 
less  than  in  the  segments  below. — These  and  similar  statements,  however,  have 
been  recently  met  by  Prof.  Kblliker,1  who  inclines  to  the  first  of  the  doctrines 
stated  in  the  preceding  paragraph;  his  own  researches  having  led  him  to  a  con- 
clusion opposed  to  that  of  Volkmann,  although  he  was  at  one  time  disposed  to 
coincide  with  it.  He  has  assured  himself  that  in  Man  the  thickness  of  the 
white  columns  augments  from  below  upwards,  and  that  the  increase  in  the 
diameter  of  the  Cord  at  the  ganglionic  enlargements  is  due  to  the  augmentation 
of  the  gray  matter  only.  Moreover,  the  diameter  of  the  nerve-tubes  in  the 
Cord,  especially  at  its  upper  part,  is  so  much  smaller  than  the  diameter  of  the 
nerve-tubes  of  the  Nerve-roots,  that  a  large  allowance  must  be  made  for  this 
difference  in  estimating  the  relative  number  of  nerve-tubes  in  the  fibrous 
columns  of  the  Cord  and  in  the  spinal  Nerves;  and  he  asserts,  from  actual 
measurement,  that  it  is  by  no  means  impossible  for  the  fibrous  strands  of  the 
former  to  contain  all  the  nerve-tubes  which  issue  from  them  in  the  latter.  He 
has  found  himself  unable,  moreover,  to  detect  any  termination  of  nerve-fibres 
in  the  vesicular  substance  of  the  spinal  cord ;  and  hence  he  thinks  it  probable 
that  they  all  pass  upwards  to  the  brain. 

701.  The  researches  of  Prof.  Kolliker  have  thus  shown  it  to  be  quite  possible 
that  many  of  the  nerve-fibres  (to  say  the  least)  do  pass  continuously  between 
the  Encephalon  and  the  nerve-roots;  whilst  there  is  an  antecedent  probability, 
derived  from  the  relation  of  these  fibres  to  the  vesicular  substance  of  the  Cord, 
and  from  the  attributes  of  each  segment  of  the  cord  as  an  independent  ganglionic 
centre,  that  some  of  them  terminate  there.  This  probability  becomes  very  strong 
when  the  Spinal  Cord  is  compared  with  the  ventral  column  of  the  Articulata ; 
for  it  may  be  stated,  with  certainty,  that  some  of  the  root-fibres  of  the  nerves 
proceeding  from  the  latter  have  their  ganglionic  centres  in  the  vesicular  matter 
of  the  ganglia;  whilst  it  is  equally  certain  that  some  of  the  fibres  pass  along  the 
purely  fibrous  tract  of  the  cord,  directly  to  the  cephalic  ganglia,  which  they 
thus  connect  with  the  roots  of  all  the  nerves.2  But  this  fibrous  tract  terminates 
in  the  Cephalic  ganglia,  which  are  homologous,  as  already  remarked  (§  674), 
not  with  the  whole  Encephalon  of  Vertebrata,  but  with  their  "  sensory  ganglia" 
alone  ;  and  thus  analogy  would  lead  us  to  suppose  that  the  fibrous  strands 
of  the  Spinal  Cord  do  not  pass  on  continuously  to  the  Cerebrum,  but  really  ex- 
tend no  further  upwards  than  the  Corpora  Striata,  Thalami  Optici,  and  the 
other  ganglionic  centres  in  connection  with  them,  which  lie  along  the  floor  of 
the  cranial  cavity.  This  view  will  be  hereafter  shown  (Sect.  3)  to  be  in  har- 
mony with  anatomical  and  physiological  facts,  which  indicate  that  the  Cerebrum 
only  receives  its  impulses  to  action  through  the  medium  of  the  Sensory  Ganglia, 
and  that  it  reacts  upon  the  muscular  apparatus  only  through  the  same  channel. 
That  some  of  the  afferent  fibres  of  the  spinal  nerves  should  pass  continuously 
upwards  to  the  ganglia  of  tactile  sense  in  Man  and  other  Vertebrata,  as  well  as 
in  Articulated  animals,  would  seem  a  legitimate  deduction  from  the  fact  that 
such  continuity  obviously  exists  between  the  olfactive,  visual,  and  auditory 
nerves,  and  their  respective  ganglionic  centres,  no  intermediate  apparatus  of  vesi- 
cular matter  being  interposed  in  their  course ;  and  there  seems  no  reason  why 
the  motor  fibres  which  are  instrumental  in  those  movements  that  are  dependent 
upon  antecedent  or  coexistent  sensations,  should  not  pass  continuously  from 
these  sensorial  centres  to  the  muscles  which  are  called  into  action.  If  such 

1  "  Mikroskopische  Anatomie,"  Band  ii.  $  116. 

2  See  "  Princ.  of  Phys.,  Gen.  and  Comp.,"  §  768,  Am.  Ed.— The  important  facts  here  re- 
ferred to,  have  been  chiefly  substantiated  by  the  researches  of  Mr.  Newport ;  a  very  impor- 
tant addition  to  his  statements,  however,  has  been  recently  made  by  M.  Gunther,  who  has 
demonstrated  the  actual  continuity  between  the  nerve-fibres  and  the  caudate  vesicles,  in 
the  ganglia  of  the  ventral  cord  of  the  Leech. 


THE    SPINAL   CORD.  667 

be  the  case,  it  does  not  seem  at  all  improbable  that  there  should  be  a  difference 
in  different  tribes  of  animals,  as  to  the  proportion  of  fibres  which  have  their 
centres  in  the  Spinal  cord  and  in  the  Sensorial  centres  respectively;  for  in 
those  whose  ordinary  movements  of  progression,  &c.,  are  independent  of  sensa- 
tion, being  performed  through  the  reflex  action  of  the  spinal  cord,  it  might 
be  expected  that  the  chief  connection  of  the  spinal  nerves  should  be  with  its  own 
ganglionic  substance,  and  that  the  bulk  of  the  fibrous  columns  should  be  com- 
posed of  eommissural  fibres  resembling  those  which  intervene  between  the  sepa- 
rate portions  of  the  ganglionic  tract  of  the  ventral  cord  of  Articulata  ;  whilst  in 
like  manner  it  might  be  anticipated  that  in  Man,  so  large  a  part  of  whose  move- 
ments are  performed  in  obedience  to  a  mental  stimulus  and  under  the  guidance 
of  sensation,  the  longitudinal  strands  should  be  chiefly  composed  of  fibres  that 
directly  connect  the  sensorial  centres  with  the  roots  of  the  spinal  nerves.  Such 
a  difference  would  appear,  from  the  comparative  researches  of  MM.  Volkmann 
and  Kolliker,  to  exist  between  the  structure  of  the  Spinal  cord  of  the  Horse  and 
that  of  Man. 

702.  Of  the  three  doctrines  previously  stated,  then,  the  third  appears  to  be 
most  in  conformity  with  the  analogy  of  the  lower  animals;  whilst  it  is  fairly 
justified  by  all  that  is  certainly  known  of  the  anatomical  structure  of  the  Spinal 
Cord  in  Man.     When  originally  advanced  by  Mr.  Grainger,1  its  novelty  chiefly 
consisted  in  the  idea  that  any  of  the  root-fibres  of  the  spinal  nerves  have  their 
central  termination  in  the  Spinal  Cord;  and  no  doubt  was  at  that  time  entertained 
by  Anatomists  or  Physiologists,  that  the  Encephalic  fibres  pass  onwards  continu- 
ously to  the  peripheral  surface  of  the  Cerebrum,  and  directly  minister  to  volun- 
tary movement  as  well  as  to  sensation.     Consequently,  Mr.  Grainger's  view  of 
the  constitution  of  the  Spinal  Cord  was  considered  by  many  Physiologists  (among 
whom  the  Author  is  not  ashamed  to  have  himself  ranked)  as  affording  the  needed 
structural  confirmation  to  Dr.  Marshall  Hall's  hypothesis  of  a  system  of  nerve- 
fibres  ministering  to  the  reflex  action  of  the  Cord,  physiologically  distinct  from 
those  which  are  subservient  to  sensation  and  voluntary  movement.     But  when 
that  distinction  is  made  between  the  several  Encephalic  centres  which  there  now 
appears  ground  for  relying  on,  those  fibres  which  connect  them  with  the  Spinal 
nerves  are  no  longer  to  be  accounted  Cerebral,  nor  to  be  regarded  as  ministering 
to  volition ;  but,  on  the  other  hand,  are  to  be  considered  as  merely  Sensorial, 
and  as  belonging,  no  less  than  the  fibres  which  link  together  the  several  seg- 
ments of  the  Spinal  Cord  itself,  to  the  "  automatic  apparatus"  (§  677). — Thus 
the  view  here  advocated  has  a  close  physiological  resemblance  to  the  doctrine  of 
Messrs.  Todd  and  Bowman,  Volkmann,  &c. ;  whilst  it  is  in  full  conformity  with 
the  anatomical  facts  supplied  by  Prof.  Kolliker;  for,  whilst  it  recognizes  the 
white  columns  of  the  Spinal  Cord  as  chiefly  composed  of  fibres  which  form  a 
continuous  connection  between  the  nerve-roots  and  certain  Encephalic  centres, 
it  regards  these  fibres  as  really  of  the  same  order  with  those  which  are  generally 
admitted  to  pass  from  the  nerves  of  one  segment  of  the  Spinal  Cord  to  other 
segments  above  and  below  it,  the  only  difference  being  that  they  extend  them- 
selves to  its  cranial  segments :  and  it  considers  the  entire  "  automatic  apparatus" 
as  receiving  all  the  terminations  of  the  nerves,  so  that  all  impressions  upon  the 
afferent  nerves  first  operate  upon  it  (affecting  the  consciousness,  or  not,  accord- 
ing as  they  reach  the  sensory  ganglia,  or  are  arrested  in  their  progress  thither); 
and  all  motor  impulses,  whether  simply  reflex,  or  orginating  in  emotional  or 
volitional  excitement,  are  issued  from  it  through  the  nerve-trunks  to  the  mus- 
cles. 

703.  In  considering  the  functions  of  the  Spinal  Cord,  we  have  to  regard  it 
under  two  aspects;  in  the  first  place,  as  a  conductor  of  nervous  force  between 

1  "Observations  on  the  Structure  and  Functions  of  the  Spinal  Cord,"  1837. 


668  OP   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

the  Nerve-trunks  and  the  Encephalic  centres ;  and  in  the  second  place,  as  itself 
an  independent  centre  of  nervous  power.  As  a  mere  conductor  of  nervous  force, 
its  functions  are  the  same  as  those  of  a  nerve-trunk ;  for,  if  it  be  divided,  all 
the  parts  of  the  body  which  are  solely  supplied  by  nerves  coming  off  below  the 
point  of  section  are  completely  paralyzed  as  far  as  regards  sensibility  and  volun- 
tary movement ;  no  impressions  made  upon  them  having  the  least  power  to 
affect  the  consciousness,  and  no  exertion  of  the  will  being  able  to  determine 
contraction  of  their  muscles.  This  state  of  paraplegia,  which  may  be  experi- 
mentally induced  in  animals,  is  frequently  exhibited  in  Man  as  a  result  of  injury 
or  of  disease  which  seriously  implicates  the  Spinal  Cord ;  and,  as,  it  has  been 
shown  that  among  the  lower  animals  complete  reunion  of  the  Cord  may  take 
place  after  complete  division,  as  indicated  by  the  entire  restoration  of  its  func- 
tional powers  and  the  complete  redintegration  of  its  structure  (§  349),  so  have 
we  reason  to  believe  that  a  similar  regeneration  may  take  place  to  a  considerable 
extent  in  Man,  this  being  marked  by  the  gradual  return  of  sensibility  and 
power  of  voluntary  movement  in  the  lower  limbs  which  had  been  at  first  com- 
pletely paralyzed.  This  regeneration  is  of  course  less  likely  to  occur  in  cases 
of  disease,  when  the  parts  around  are  in  an  unhealthy  state,  than  when  the 
paralysis  is  due  to  injury,  which  all  the  restorative  powers  of  the  system  are 
engaged  in  repairing:  but  it  is  to  be  remembered  that,  as  the  injuries  which  are 
likely  to  cause  such  lesions  of  the  Cord  are  nearly  always  attended  with  severe 
concussion  (it  being  very  rare  for  it  to  be  accidentally  wounded  by  the  penetra- 
tion of  a  sharp  instrument  between  the  vertebrae,  in  the  mode  in  which  experi- 
ments are  made  upon  animals),  some  of  their  first  effects  are  attributable  to  the 
shock  which  it  has  sustained;  so  that  the  partial  recovery  which  takes  place  at 
an  early  period  must  not  be  regarded  as  the  result  of  regeneration  of  nervous 
tissue,  which  requires  a  much  longer  time  for  its  completion. 

704.  The  conducting  power  of  the  entire  Spinal  Cord  being  thus  established, 
we  have  next  to  inquire  whether  any  difference  in  endowment  can  be  shown  to 
exist  in  its  several  columns.  By  Sir  C.  Bell,  it  was  supposed  that  the  anterior 
columns  possess  the  same  endowments  as  the  anterior  roots  of  the  nerves,  and 
the  posterior  columns  the  same  as  the  posterior  roots }  and  this  view  is  supported 
by  the  experiments  of  Longet,1  who  deduces  from  them  the  conclusion,  that 
irritation  of  the  posterior  columns,  as  of  the  posterior  nerve-roots,  gives  rise  to 
excruciating  pain,  without  exciting  any  other  movements  than  such  as  are  called 
into  action  in  reflex  respondence  to  the  impression,  and  that  irritation  of  the 
anterior  columns  excites  movements  directly  (or  without  reflexion),  and  is  not 
a  source  of  pain.  Again,  he  found  that  when  the  Spinal  Cord  was  completely 
divided,  and  time  was  allowed  for  the  reflex  activity  of  the  cord  to  subside  (this 
disappearing  rapidly  in  adult  warm-blooded  animals),  the  application  of  an 
electric  current  to  the  posterior  columns  of  the  separated  part  occasioned  no 
movement  whatever,  whilst  its  transmission  through  the  anterior  columns  called 
forth  vigorous  movements.  Moreover,  he  states  that  the  effects  of  the  reversal 
of  the  electric  current,  transmitted  through  the  anterior  columns,  were  the  same 
as  those  of  the  same  reversal  when  the  currents  were  transmitted  through  the 
anterior  roots  of  the  spinal  nerves1;  whilst  they  differed  from  those  produced  by 
the  same  change  in  the  direction  of  the  currents,  transmitted  through  a  nerve 
of  mixed  endowments. — The  researches  of  Van  Deen3  lead  on  the  whole  to 
the  same  conclusions :  but  they  tend,  in  his  opinion,  to  show  that  the  conduct- 
ing power  both  of  the  anterior  and  posterior  columns  is  very  imperfect,  if  their 
white  strands  be  completely  separated  from  their  gray  matter.  His  experiments 

1  "Anatomic  et  Physiologie  du  Systeme  Nerveux,"  1842  ;  and  "  Traite  de  Physiologic," 
1850,  torn.  ii.  pp.  184-8. 

2  "Traites  et  Decouvertes  sur  la  Physiologie  et  la  Moelle  Epiniere,"  Leide,  1841. 


THE    SPINAL   CORD.  669 

appear  to  have  conclusively  established  that  the  gray  matter,  as  well  as  the 
white,  possesses  conducting  powers;  as  we  might  indeed  anticipate  from  the 
circumstance,  that  it  contains  a  large  amount  of  the  fibrous  form  of  nerve-tissue, 
and  that  the  commissural  connection  between  the  two  lateral  halves  of  the  Cord 
is  established  (according  to  Mr.  J.  L.  Clarke,  §  696)  by  its  gray  substance 
alone.  That  a  ready  transverse  communication  exists,  is  proved  not  merely 
by  the  fact  that  an  impression  made  upon  a  nerve  of  one  side  will  very  com- 
monly excite  reflex  movements  on  both;  but  also  by  the  experiment  of  com- 
pletely dividing  one-half  of  the  cord  as  far  as  the  median  line,  and  dividing  the 
other  half  to  the  same  extent  a  short  distance  below  the  first  section ;  for  this 
operation  does  interrupt  the  transmission  of  sensory  impressions,  although  it 
seems  doubtful  whether  motor  influences  can  be  thus  propagated.1 — The  experi- 
mental results  of  Stilling,3  again,  are  on  the  whole  in  harmony  with  the  pre- 
ceding; but  he  lays  yet  greater  stress  than  Van  Deen  on  the  importance  of  the 
gray  matter  to  even  the  conductive  power  of  the  white. — These  deductions, 
however,  are  strongly  opposed  by  Longet,  who  affirms  that  he  could  never  ob- 
tain any  evidence  either  of  sensibility  or  of  motor  power,  on  irritating  the  gray 
substance  alone  by  the  electric  current;  and  that,  on  the  other  hand,  the  entire 
destruction  of  the  gray  matter  for  a  considerable  length,  by  means  of  a  rod 
introduced  into  the  interior  of  the  Cord,  did  not  seem  in  any  degree  to  impair 
the  conducting  power  of  its  columns.  It  must  be  borne  in  mind,  however,  that 
there  are  numerous  pathological  phenomena,  which  it  is  very  difficult  to  recon- 
cile with  the  foregoing  conclusions  regarding  the  relative  functions  of  the 
anterior  and  posterior  columns  of  the  Spinal  Cord;  cases  having  occurred,  in 
which  complete  destruction  of  the  anterior  columns  appeared  to  have  taken 
place,  without  loss  of  voluntary  motion  in  the  parts  below ;  whilst  a  similar 
destruction  of  the  posterior  columns  has  occurred  without  corresponding  lesion 
of  sensibility.3  But  it  must  be  borne  in  mind  that  we  are  still  far  from  having 
an  accurate  knowledge  of  the  degree  of  structural  change  in  the  nervous  centres, 
which  is  incompatible  with  the  continued  performance  of  their  functions;  and 
that  there  are  instances  in  which  the  whole  thickness  of  the  cord  has  under- 
gone softening  and  apparent  disintegration,  without  the  destruction  of  the 
functional  connection  between  the  Encephalon  and  the  parts  below  the  seat  of 
the  disease.4 

1  A  case  is  cited  by  Longet  from  Begin,  in  which  a  man  was  stabbed  at  the  back  of  the 
neck,  the  point  of  the  knife  passing  obliquely  forwards  between  the  sixth  and  seventh 
cervical  vertebrae,  dividing  the  antero-lateral  and  anterior  columns  of  the  Spinal  Cord  on 
the  right  side.     He  survived  the  injury  six  days ;  and  suffered  from  complete  paralysis  of 
motion  of  the  corresponding  lower  extremity,  with  incomplete  paralysis  of  motion  of  the 
right  arm  ;  the  sensibility  remaining  perfect.     This  case  seems  to  show  that  the  Will  has 
no  power  to  direct  its  motor  impulses  across  the  cord ;  since  the  parts  deriving  their  nerves 
from  the  part  of  the  cord  below  the  partial  section  were  entirely  withdrawn  from  its  in- 
fluence. 

2  "  Untersuchungen  iiber  die  Functionen  des  Ruckenmarks  und  die  Nerven,"  Leipzig, 
1842. 

3  See  especially  the  case  recorded  by  Mr.  Stanley  in  "Med.-Chir.  Transact.,"  vol.  xxiii. 
and  by  Dr.  Webster,  Op.  cit.,  vol.  xxvi. 

4  See,  for  example,  the  case  of  "Softening  of  the  Spinal  Marrow,"  recorded  by  Dr. 
Nairne  in  the  "Med.-Chir.  Trans.,"  vol.  xxxiv. ;  in  which  a  portion  of  the  Cord  at  least 
an  inch  long,  situated  opposite  the  third  and  fourth  dorsal  vertebrae,  was  "  so  soft  that  the 
slightest  pressure  of  the  finger  broke  it  up,"  being  nearly  in  a  fluid  state  through  its 
whole  thickness ;  yet  the  patient  felt  pain  in  his  lower  limbs,  showing  that  the  power  of 
upward  transmission  remained ;  and,  although  he  had  lost  all  voluntary  control  over  the 
muscles  of  the  lower  part  of  the  body,  yet  they  were  affected  with  incessant  choreic  move- 
ment (which,  as  will  be  shown  hereafter,  Sect.  7,  appears  to  originate  in  the  Sensory 
Ganglia),  and  these  movements  were  affected  in  such  a  marked  manner  by  emotions,  as 
plainly  to  indicate  a  downward  transmission  of  motor  power. 


670  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

[The  experiments  of  Dr.  Brown-Sequard,  witnessed  by  the  editor,  are  also 
confirmatory  of  the  results  obtained  by  Van  Deen,  Stilling,  Longet,  and  Clarke. 
Section  of  the  posterior  column  on  either  side  diminished  the  sensibility  of  the 
opposite  side,  at  the  same  time  that  the  operation  caused  great  pain.  Section 
of  the  whole  of  the  white  matter  of  the  cord,  however,  did  not  destroy  sensi- 
bility entirely,  so  long  as  the  central  gray  matter  was  uninjured,  thus  showing 
that  it,  as  well  as  the  white  matter,  was  a  medium  for  the  conduction  of  sen- 
sory impressions.  An  interesting  fact  has  been  witnessed  in  connection  with 
these  experiments,  viz. :  a  degeneration  of  the  tract  of  white  fibres  on  the  op- 
posite side  from  the  wound,  evidenced  by  the  deposition  of  granular  cells,  the 
beginning  of  a  metamorphosis  to  be  perfected  after  a  lapse  of  time.  This  de- 
generation has  been  shown  by  Dr.  Turck,  of  Vienna,  to  be  a  consequence  of 
abrogation  of  function,  the  result  either  of  disease  or  experiment  j1  and  it  mani- 
fests itself  both  in  the  sensory  and  motor  tracts,  whenever  the  transmission 
of  motor  impulses  or  sensory  impressions  has  been  arrested.  The  gray  matter 
is  not  subject  to  the  formation  within  it  of  these  abnormal  cells,  from  which, 
however,  no  conclusion  can  be  absolutely  drawn  with  regard  to  its  power  of  con- 
duction.— ED.] 

705.  It  is  difficult  to  reconcile  with  the  experimental  results  already  cited, 
those  of  other  Physiologists,  which  appear  to  show  that  the  anterior  and  pos- 
terior divisions  of  the  Spinal  Cord  respectively  minister  to  the  motions  of  flexion 
and  extension.  This  notion,  which  originated  with  Bellingeri,2  was  afterwards 
advocated  by  Valentin,3  who  inferred  from  his  experiments  that,  if  the  posterior 
column  of  the  Spinal  Cord  of  the  Frog  be  irritated  at  the  point  at  which  the 
nerves  of  either  extremity  are  given  off,  that  extremity  is  extended,  and  that  if 
the  anterior  column  be  irritated,  the  extremity  is  flexed;  so  that,  since  he  ad- 
mitted the  anterior  columns  to  be  chiefly  motor,  and  the  posterior  to  be  for  the 
most  part  sensory,  it  would  appear  that  the  motor  fibres  of  the  extensors  pass 
from  the  anterior  into  the  posterior  column,  whilst  those  of  the  flexors  are  con- 
tinued onwards  in  the  anterior  column.  Confirmation  of  this  inference  was 
obtained  by  Valentin  from  experiments  on  Mammalia ;  and  it  is  borne  out  ac- 
cording to  him,  by  pathological  phenomena  observed  in  Man.  According  to 
this  eminent  physiologist,  also,  relaxation  of  the  sphincters  is  analogous  to  the 
extended  state  of  the  extremities ;  and  he  has  noticed  a  manifest  relaxation  of 
the  sphincter  ani  in  the  frog,  when  the  superior  part  of  the  spinal  cord  was  irri- 
tated, so  as  to  produce  extension  of  the  limbs.  The  experiments  of  Budge* 
and  Engelhardt,3  however,  led  them  to  an  opposite  conclusion ;  for  it  appeared 
to  them  that,  in  Mammalia,  the  nerve-fibres  which  act  upon  the  extensor  mus- 
cles are  contained  in  the  anterior  columns,  and  those  of  the  flexor  muscles  in 
the  posterior  columns;  whilst,  as  regards  the  Frog,  the  nerve-fibres  connected 
with  the  extensor  muscles  appeared  to  be  situated  posteriorly  to  those  of  the 
flexors.  The  experiments  of  Harless,6  again,  have  led  him  to  regard  the  upper 
part  of  the  spinal  cord  in  the  Frog,  between  the  2d  and  4th  vertebrae  inclusive, 
as  specially  concerned  in  the  flexion  both  of  the  anterior  and  posterior  extremi- 
ties; and  the  lower  part,  from  the  5th  to  the  8th  vertebrae  inclusive,  as  in  like 
manner  concerned  in  their  extension.  All  .these  results  can  only  at  present  be 
accepted  as  indicating  that  some  such  special  arrangement  of  the  nerve-fibres  in 
the  Spinal  Cord,  having  reference  to  the  combination  of  different  muscular 
actions  in  groups,  may  have  a  real  existence ;  there  is  far  too  little  accordance, 

•  "  Uber  Secondare  Erkrankung  einzelner  Ruckenmarksstriinge  und  ihren  Fortsetzungen 
zum  Gebirne,"  Vienna,  1851. 

2  "De  Medulla  Spinali,  nervisque  ex  ea  prodeuntibus,"  &c.,  Turin,  1823. 

3  "De  Functionibus  Nervorum  Cerebralium  et  Nervi  Sympathici,"  Bernse,  1830. 

4  "  Untersuchungen  iiberdas  Nervensystem,"  1841. 

6  "Miiller's  Archiv.,"  heft  3,  1841.     '  6  «  Muller's  Arcliiv.,"  1846. 


THE   SPINAL   CORD.  671 

however,  among  the  phenomena  described  by  different  observers,  to  enable  even 
a  probable  statement  to  be  hazarded  in  regard  to  the  nature  of  this  arrangement; 
and  it  seems  quite  possible  that  it  may  vary  in  different  animals,  in  accordance 
with  their  respective  modes  of  progression.  As  far  as  Man  is  concerned,  we 
have  no  evidence  but  that  of  pathological  phenomena ;  and  we  certainly  may 
find,  in  many  forms  of  convulsive  action,  an  indication  that  there  is  some  com- 
mon centre  or  tract  of  motor  impulse  for  the  extensor  muscles  generally,  and 
another  such  centre  or  tract  for  the  flexors. 

706.  We  have  now  to  consider  the  Spinal  Cord  as  an  independent  centre  of 
nervous  power,  and  to  inquire  whether  the  movements  which  are  excited  through 
its  "reflex  activity  really  involve  sensation.  These  movements  are  most  cha- 
racteristically displayed,  when  the  Spinal  Cord  is  cut  off  from  communication 
with  the  higher  Nervous  centres ;  probably  rather  because  the  nerve-force  ex- 
cited by  the  impression  reacts  through  the  Spinal  ganglion  to  which  it  is  con- 
veyed, when  it  can  no  longer  pass  on  to  the  Encephalic  centres  (§  683),  than 
because  (as  some  suppose)  the  impulse  to  reflex  movement  is  ordinarily  neutral- 
ized and  rendered  inoperative  by  an  effort  of  the  will.  It  is  true  that  those 
reflex  actions  of  the  Spinal  Cord  which  are  necessary  to  the  maintenance  of 
Organic  life,  and  which  are  equally  performed  whether  the  Spinal  axis  be  in 
communication  with  the  higher  Encephalic  centres  or  not,  are  continually  modi- 
fied or  temporarily  suspended  by  the  Will;  but  this  is  only  when  we  consciously 
bring  the  Will  to  bear  upon  them ;  and  it  is  no  less  certain  that  we  are  not 
continually  making  any  such  exertions,  in  order  to  antagonize  movements, 
which  (as  we  learn  from  Pathological  evidence),  would  be  continually  excited 
but  for  this  neutralizing  influence,  if  such  a  doctrine  were  correct.  The  readiest 
demonstration  of  the  independent  power  of  the  Spinal  Cord  is  derived  from  the 
motions  exhibited  by  the  limbs  of  animals,  when  irritation  is  applied  to  them 
after  section  of  the  Spinal  Cord  at  some  point  above  the  entrance  of  their 
nerves ;  the  fact  that  these  movements  are  reflected  through  the  Cord,  and  are 
not  the  product  of  direct  stimulation  applied  to  the  part  irritated,  being  shown 
by  their  complete  cessation  when  the  nerve-trunks  are  divided,  or  the  substance 
of  the  Spinal  Cord  is  broken  down.  Further,  it  is  to  be  observed  that  a  slight 
irritation  applied  to  the  peripheral  extremities  of  the  afferent  nerves,  is  a  more 
powerful  excitor  of  reflex  action  than  a  much  stronger  impression,  which  occa- 
sions acute  pain,  applied  to  their  trunks;  thus,  Mr.  Grainger  found  that  he  could 
remove  the  entire  hind-leg  of  a  Salamander  with  the  scissors,  without  the  'crea- 
ture moving,  or  giving  any  expression  of  suffering,  if  the  Spinal  Cord  had  been 
first  divided;  yet  that  by  irritation  of  the  foot,  especially  by  heat,  in  an  animal 
similarly  circumstanced,  violent  convulsive  actions  in  the  legs  and  tail  were  ex- 
cited. This  fact  is  important,  not  only  as  showing  the  comparatively  powerful 
effect  of  impressions  upon  the  cutaneous  surface,  but  also  as  proving  how  little 
relation  the  amount  of  reflex  action  has  to  the  intensity  of  sensation.  [When 
the  cutaneous  surface  is  removed,  reflex  action  can  scarcely  be  excited  at  all  by 
impressions,  even  of  the  most  irritating  character,  as  we  have  seen  repeatedly  in 
frogs  whose  inferior  extremities  have  been  denuded  of  cuticle. — ED.]  That  the 
movements  executed  by  the  limbs  of  the  lower  animals,  when  these  are  no  longer 
connected  by  the  Spinal  Cord  with  the  Encephalon,  but  remain  connected  with 
the  Cord  itself,  do  not  take  place  through  the  intermediation  of  sensation,  might 
be  supposed  to  be  sufficiently  proved  by  the  simple  fact  that  division  of  the 
Cord,  in  Man,  and  hence  by  inference  in  the  lower  animals,  reduces  the  parts 
below  to  a  state  of  complete  insensibility.  But,  on  the  other  hand,  the  very 
performance,  by  decapitated  animals  of  inferior  tribes,  of  actions  which  had  not 
been  witnessed  in  Man  under  similar  circumstances,  has  been  held  to  indicate 
that  the  spinal  cord  in  them  has  an  endowment  which  his  does  not  possess.  The 
possibility  of  such  an  explanation,  however  unconformable  to  that  analogy 


672  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

throughout  organized  nature,  which,  the  more  it  is  studied,  the  more  invariably 
is  found  to  guide  to  truth,  could  not  be  disproved.  Whatever  experiments  on 
decapitated  animals  were  appealed  to,  in  support  of  the  doctrine  that  the  Brain 
contains  the  only  seat  of  sensibility,  could  be  met  by  a  simple  denial  that  the 
Spinal  Cord  is  everywhere  as  destitute  of  that  endowment  as  it  appears  to  be  in 
Man.  The  cases  of  profound  sleep  and  apoplexy  might  be  cited  as  examples  of 
reflex  action  without  consciousness;  but  these  have  been  met  by  the  assertion 
that  in  such  conditions  sensations  are  felt,  though  they  are  not  remembered.  It 
is  difficult,  however,  to  apply  such  an  explanation  to  the  case  of  anencephalous 
human  infants  (in  which  all  the  ordinary  reflex  actions  have  been  exhibited, 
with  an  entire  absence  of  brain),  without  supposing  that  the  Medulla  Oblongata 
is  the  seat  of  a  sensibility  which  we  know  that  the  lower  part  of  the  Spinal 
Cord  does  not  possess;  and  of  this  there  is  no  evidence  whatever.  Experiments 
on  the  lower  animals,  then,  and  observation  of  the  phenomena  manifested  by 
apoplectic  patients  and  anencephalous  infants,  might  lead  to  the  conclusion 
that  the  Spinal  Cord  does  not  itself  possess  sensibility,  and  that  its  reflex  actions 
are  independent  of  sensation.  At  this  conclusion,  Unzer,  Prochaska,  Sir  Gr. 
Blane,  Flourens,  and  other  physiologists,  had  arrived;  but  it  was  not  until 
special  attention  was  directed  to  the  subject  by  Dr.  M.  Hall,  that  facts  were 
obtained  by  which  a  positive  statement  of  it  could  be  supported.  For  the 
question  might  have  been  continually  asked — If  the  Spinal  Cord  in  Man  be 
precisely  analogous  in  function  to  that  of  the  lower  Vertebrata,  why  are  not  its 
reflex  phenomena  manifested,  when  a  portion  of  it  is  severed  from  the  rest  by 
disease  or  injury  ?  The  answer  to  this  question  is  twofold.  In  the  first  place, 
simple  division  of  the  cord  with  a  sharp  instrument  leaves  the  separated  por- 
tion in  a  state  of  much  more  complete  integrity,  and  therefore  in  a  state  much 
more  fit  for  the  performance  of  its  peculiar  functions,  than  it  ordinarily  is  after 
disease  or  violent  injury ;  and  as  the  former  method  of  division  is  one  with  which 
the  Physiologist  is  not  likely  to  meet  in  Man  as  a  result  of  accident,  and  which 
he  cannot  experimentally  put  in  practice,  the  cases  in  which  reflex  actions  would 
be  manifested  are  likely  to  be  comparatively  few.  But,  secondly,  a  sufficient 
number  of  such  instances  have  now  been  accumulated,  to  prove  that  the  occur- 
rence is  by  no  means  so  rare  as  might  have  been  supposed;  and  that  nothing  is 
required  but  patient  observation,  to  throw  a  great  light  on  this  interesting 
question,  from  the  phenomena  of  disease.  A  most  valuable  collection  of  such 
cases,  occurring  within  his  own  experience,  has  been  published  by  Dr.  W. 
Budd;1  and  the  leading  facts  observed  by  him  will  be  now  enumerated. 

707.  In  the  first  case,  paraplegia  was  the  result  of  angular  distortion  of  the 
spine  in  the  dorsal  region.  The  sensibility  of  the  lower  extremities  was  ex- 
tremely feeble,  and  the  power  of  voluntary  motion  was  almost  entirely  lost. 
u  When,  however,  any  part  of  skin  is  pinched  or  pricked,  the  limb  that  is  thus 
acted  on  jumps  with  great  vivacity ;  the  toes  are  retracted  towards  the  instep, 
the  foot  is  raised  on  the  heel,  and  the  knee  so  flexed  as  to  raise  it  off  the  bed  ; 
the  limb  is  maintained  in  this  state  of  tension  for  several  seconds  after  the 
withdrawal  of  the  stimulus,  and  then  becomes  suddenly  relaxed."  "  In  gen- 
eral, while  one  leg  was  convulsed,  its  fellow  remained  quiet,  unless  stimulus 
was  applied  to  both  at  once."  "  In  these  instances,  the  pricking  and  pinching 
were  perceived  by  the  patient ;  but  'much  more  violent  contractions  are  excited 
by  a  stimulus,  of  whose  presence  he  is  unconscious.  When  a  feather  is  passed 
lightly  over  the  skin,  in  the  hollow  of  the  instep,  as  if  to  tickle,  convulsions 
occur  in  the  corresponding  limb,  much  more  vigorous  than  those  induced  by 
pinching  or  pricking ;  they  succeed  one  another  in  a  rapid  series  of  jerks,  which 
are  repeated  as  long  as  the  stimulus  is  maintained."  "  When  any  part  of 

1  "  Medico-Chirurgical  Transactions,"  vol.  xxii. 


THE    SPINAL   CORD.  673 

the  limb  is  irritated  in  the  same  way,  the  convulsions  which  ensue  are  very 
feeble,  and  much  less  powerful  than  those  induced  by  pricking  or  pinching." 
"  Convulsions,  identical  with  those  already  described,  are  at  all  times  excited  by 
the  acts  of  defecation  and  micturition.  At  these  times,  the  convulsions  are 
much  more  vigorous  than  under  any  other  circumstances,  insomuch  that  the 
patient  has  been  obliged  to  resort  to  mechanical  means  to  secure  his  person 
while  engaged  in  these  acts.  During  the  act  of  expulsion,  the  convulsions  suc- 
ceed one  another  rapidly,  the  urine  is  discharged  in  interrupted  jets,  and  the 
passage  of  the  feces  suffers  a  like  interruption."  The  convulsions  are  more 
vigorous,  the  greater  the  accumulation  of  urine ;  and  involuntary  contractions 
occur  whenever  the  bladder  is  distended,  and  also  when  the  desire  to  relieve  the 
rectum  is  manifested.  "  In  all  these  circumstances,  the  convulsions  are  per- 
fectly involuntary ;  and  he  is  unable,  by  any  effort  of  the  will,  to  control  or 
moderate  them."  The  patient  subsequently  regained,  in  a  gradual  manner,  both 
the  sensibility  of  the  lower  extremities,  and  voluntary  power  over  them ;  and  as 
voluntary  power  increased,  the  susceptibility  to  involuntary  movements,  and 
the  extent  and  power  of  these,  diminished. — This  case,  then,  exhibits  an  increased 
tendency  to  perform  reflex  actions,  when  the  control  of  the  brain  was  removed ; 
and  it  also  shows  that  a  slight  impression  upon  the  surface,  of  which  the  patient 
was  not  conscious,  was  more  efficacious  in  exciting  reflex  movements,  than  were 
others  that  more  powerfully  affected  the  sensory  organs. — It  should  be  added 
that,  in  the  foregoing  case,  the  nutrition  of  the  lower  extremities  was  not  im- 
paired, as  in  most  cases  of  paraplegia ;  the  rationale  of  this  phenomenon,  which 
is  to  be  constantly  observed  when  the  reflex  actions  of  the  part  remain  entire, 
will  be  understood  by  reference  to  §  325. 

708.  In  another  case,  the  paralysis  was  more  extensive,  having  been  pro- 
duced by  an  injury  (resulting  from  a  fall  into  the  hold  of  a  vessel)  at  the  lower 
part  of  the  neck.  There  was  at  first  a  total  loss  of  voluntary  power  over  the 
lower  extremities,  trunk,  and  hands ;  slight  remaining  voluntary  power  in  the 
wrists,  rather  more  in  the  elbows,  and  still  more  in  the  shoulders.  The  inter- 
costal muscles  did  not  participate  in  the  movements  of  respiration.  The  sensi- 
bility of  the  hands  and  feet  was  greatly  impaired.  There  were  retention  of 
urine,  and  involuntary  evacuation  of  the  feces.  Recovery  took  place  very 
gradually ;  and  during  its  progress,  several  remarkable  phenomena  of  reflex 
action  were  observed.  At  first,  tickling  one  sole  excited  to  movement  that 
limb  only  which  was  acted  upon ;  afterwards,  tickling  either  sole  excited 
both  legs,  and,  on  the  26th  day,  not  only  the  lower  extremities,  but  the  trunk 
and  other  extremities  also.  Irritating  the  soles,  by  tickling  or  otherwise,  was 
at  first  the  only  method,  and  always  the  most  efficient  one,  by  which  convulsions 
could  be  excited.  From  the  26th  to  the  69th  day,  involuntary  movements  in 
all  the  palsied  parts  continued  powerful  and  extensive,  and  were  excited  by  the 
following  causes  :  in  the  lower  extremities  only,  by  the  passage  of  flatus  from 
the  bowels,  or  by  the  contact  of  a  cold  urinal  with  the  penis  ;  convulsions  in  the 
upper  extremities  and  trunk,  attended  with  sighing,  by  plucking  the  hair  of  the 
pubes.  On  the  41st  day,  a  hot  plate  of  metal  was  applied  to  the  soles,  and 
found  a  more  powerful  excitor  of  movement  than  any  before  tried.  The  move- 
ments continued  as  long  as  the  hot  plate  was  kept  applied ;  but  the  same  plate, 
at  the  common  temperature,  excited  no  movements  after  the  first  contact.  The 
contact  was  distinctly  felt  by  the  patient;  but  no  sensation  of  heat  was  per- 
ceived by  him,  although  the  plate  was  applied  hot  enough  to  cause  vesication. 
At  three  different  intervals,  the  patient  took  one-eighth  of  a  grain  of  strychnia 
three  times  a  day.  Great  increase  of  susceptibility  to  involuntary  movements 
immediately  followed,  and  they  were  excited  by  the  slightest  causes.  No  con- 
vulsions of  the  upper  extremities  could  ever  be  produced,  however,  by  irri- 
tating their  inteugment ;  though,  under  the  influence  of  strychnia,  pulling  the 
43 


674  Or   THE   FUNCTIONS    OP   THE    NERVOUS    SYSTEM. 

hair  of  the  head,  or  tickling  the  chin,  would  occasion  violent  spasmodic  actions 
in  them.  Spontaneous  convulsions  of  the  palsied  parts,  which  occurred  at  other 
times,  were  more  frequent  and  more  powerful  after  the  use  of  strychnia.  On 
the  first  return  of  voluntary  power,  the  patient  was  enabled  to  restrain  in  some 
measure  the  excited  movements  :  but  this  required  a  distinct  eifort  of  the  will ; 
and  the  first  attempts  to  walk  were  curiously  affected,  by  the  persistence  of  the 
susceptibility  to  excited  involuntary  movements.  When  he  first  attempted  to 
stand,  the  knees  immediately  became  forcibly  bent  under  him ;  this  action  of 
the  legs  being  excited  by  contact  of  the  soles  with  the  ground.  On  the  95th 
day  this  effect  did  not  take  place,  until  the  patient  had  made  a  few  steps  ;  the 
legs  then  had  a  tendency  to  bend-up,  a  movement  which  he  counteracted  by 
rubbing  the  surface  of  the  belly ;  this  rubbing  excited  the  extensors  to  action, 
and  the  legs  became  extended  with  a  jerk.  A  few  more  steps  were  then  made; 
the  manoeuvre  repeated,  and  so  on.  This  susceptibility  to  involuntary  move-- 
ments  from  impressions  on  the  soles,  gradually  diminished ;  and  on  the  141st 
day,  the  patient  was  able  to  walk  about,  supporting  himself  on  the  back  of  a 
chair  which  he  pushed  before  him;  but  his  gait  was  unsteady,  and  much 
resembled  that  of  chorea.  Sensation  improved  very  slowly :  it  was  on  the 
53d  day  that  he  first  slightly  perceived  the  heat  of  the  metal  plate. — Now  in 
this  case,  the  abolition  of  common  sensation  was  not  so  complete  as  in  the  for- 
mer instance ;  but  of  the  peculiar  kind  of  impression,  which  was  found  most 
efficacious  in  exciting  reflex  movements,  no  consciousness  whatever  was  experienced. 
Not  less  interesting  was  the  circumstance,  that  convulsions  could  be  readily  ex- 
cited by  impressions  on  surfaces  above  the  seat  of  injury  :  as,  by  pulling  the 
hair  of  the  scalp,  a  sudden  noise,  and  so  on.  This  proves  two  important  points  : 
first,  that  a  lesion  of  the  cord  may  be  such  as  to  intercept  the  transmission  of 
voluntary  influence,  and  yet  may  allow  the  transmission  of  that  reflected  from 
incident  nerves.  Secondly,  that  all  influences  from  impressions  on  incident 
nerves  are  diffused  through  the  cord ;  for,  in  the  instance  adduced,  the  reflected 
influence  was  undoubtedly  not  made  to  deviate  into  the  cord  by  the  morbid  con- 
dition of  that  organ,  but  followed  its  natural  course  of  diffusion,  being  rendered 
manifest  in  this  case  by  the  convulsions  which  were  excited,  in  consequence  of 
increased  activity  of  the  motor  function  of  the  cord.  It  is  further  interesting 
to  remark,  that,  in  the  foregoing  case,  the  reflex  actions  were  very  feeble  during 
the  first  seven  days,  in  comparison  with  their  subsequent  energy ;  being  limited 
to  slight  movements  of  the  feet,  which  could  not  always  be  excited  by  tickling 
the  soles.  In  another  case  of  very  similar  character,  it  was  three  days  after  the 
accident  before  any  reflex  actions  could  be  produced.  It  is  evident,  then,  that 
the  spinal  cord  must  have  been  in  a  state  of  concussion,  which  prevented  the 
manifestation  of  its  peculiar  functions,  so  long  as  this  effect  lasted ;  and  it  is 
easy,  therefore,  to  perceive,  that  a  still  more  severe  shock  might  permanently 
destroy  its  power,  so  as  to  prevent  the  exhibition  of  any  of  the  phenomena  of 
reflex  action. 

709.  So  many  cases  of  this  kind  have  now  occurred,  that  it  may  be  consid- 
ered as  a  demonstrated  fact,  that  the  Spinal  Cord,  or  insulated  portions  of  it, 
may  serve  in  Man,  no  less  than  in  the  lower  animals,  as  the  centre  of  very  en- 
ergetic reflex  actions,  when  the  Encephalic  power  which  ordinarily  operates 
through  it  is  suspended  or  destroyed,  or  when  it  is  prevented  from  influencing 
the  Spinal  nerves  by  such  an  injury  to  the  Cord  above  their  points  of  connection 
with  it,  as  prevents  the  transmission  of  nervous  polarity  :  and  it  is  further  evi- 
dent that  these  movements  are  not  more  dependent  upon  sensation,  than  they 
are  upon  the  will,  since  they  may  be  excited  without  the  consciousness  of  the 
individual,  even  when  this  is  fully  directed  to  the  part.1  And  we  thus  have 

1  The  Author  is  informed  by  his  friend  Mr.  Paget,  that  among  the  notes  left  by  John 
Hunter  (which  furnished  some  of  the  materials  for  the  admirable  Catalogue  of  the  Pa- 


THE    SPINAL   COED.  675 

adequate  ground  for  the  assertion,  that  the  movements  which  may  be  called 
forth  by  stimulation  in  the  states  of  profound  Sleep  or  Coma,  are  not  to  be  held 
to  indicate  that  sensation  is  even  momentarily  excited ;  since  we  know  that  the 
reflex  power  of  the  Spinal  Cord  may  be  called  into  action  by  impressions  which 
do  not  travel  onwards  to  the  sensoriuni,  or  which  are  powerless  to  affect  the  con- 
sciousness even  when  they  arrive  there.  [That  the  source  of  the  reflex  faculty 
is  to  be  looked  for  in  the  spinal  cord  itself,  may  be  shown  by  the  simple  experi- 
ment of  rapidly  exciting  reflex  action  in  a  decapitated  animal.  It  will  be  found 
that,  after  exhausting  it  entirely,  it  will  reappear  and  become  as  energetic  as 
before,  provided  the  circulation  is  kept  up  in  the  cord.  Moreover,  if  the  action 
of  the  spinal  cord  be  rapidly  excited,  it  is  capable  of  producing  an  amount  of 
muscular  contraction  in  a  frog's  leg  sufficient  to  raise,  in  divided  portions,  a 
weight  of  twelve  pounds  to  a  height  of  two  lines.  In  a  pigeon  it  can  produce 
an  amount  of  contraction  sufficient  to  raise,  also  in  divided  portions,  fifty  pounds 
to  the  height  of  two  inches  in  the  course  of  an  hour.  That  the  reflex  power  is 
not  derived  from  the  medulla  oblongata,  as  was  supposed  by  Arnold  and 
Flourens,  is  shown  by  the  fact  that  it  (the  reflex  power)  is  very  weak  in  frogs 
immediately  after  the  separation  of  the  cord  from  the  medulla  oblongata,  and 
that  it  increases  afterwards  to  such  a  degree  as  to  elevate  by  muscular  contrac- 
tion more  than  double  the  weight  which  the  influence  of  the  will  could  ac- 
complish before  the  division. 

The  injection  of  blood  into  the  carotid  of  an  animal  recently  dead  by  hemor- 
rhage, and  in  whom  reflex  action  had  ceased,  is  speedily  followed  by  a  return 
of  that  faculty  of  the  cord,  even  after  its  separation.1 — ED.]  These  reflex  actions 
of  the  Spinal  Cord  have  much  more  regularity  and  apparent  purposiveness  in  the 
lower  Vertebrata,  approaching  in  this  respect  to  the  reflex  actions  of  the  gan- 
glionic  column  of  Articulata,  than  they  have  in  Man.  For  we  see  that  when  a 
portion  of  his  Spinal  Cord  is  withdrawn  from  the  influence  of  the  Cerebrum,  the 
reflex  actions  that  may  be  excited  in  the  limbs  with  which  it  has  nervous  connec- 
tion, are  disorderly  and  purposeless  in  their  character,  notwithstanding  that  they 
may  be  powerful;  whilst,  on  the  other  hand,  if  a  Frog  be  decapitated,  its  body  is 
still  supported  on  its  limbs  in  the  usual  position,  and  will  recover  this  if  it  be 
disturbed ;  irritation  of  the  feet  will  cause  it  to  leap ;  tickling  the  cloaca  with 
a  probe  will  excite  efforts  to  push  away  the  instrument ;  in  fact,  the  movements 
altogether  show  almost  as  much  adaptiveness  and  regularity,  as  if  the  mind  of 
the  animal  were  engaged  in  directing  them.  It  would  seem  absurd,  however,  to 
attribute  any  psychical  agency  to  the  Spinal  Cord  ;  since,  to  remove  these  move- 
ments from  the  category  of  automatic  actions,  we  must  attribute  to  that  organ 
a  power,  not  merely  of  feeling,  but  also  of  choosing  and  directing  movements 
with  a  conscious  design  ;  and  all  our  knowledge  of  the  functions  of  the  Nervous 
System  tends  to  the  belief  that  such  attributes  belong  only  to  the  Brain. 
Hence,  the  adaptiveness  of  the  reflex  actions  performed  by  many  of  the  lower 
tribes  of  animals  can  only  be  held  to  indicate  that  a  larger  share  of  such 
adaptation  is  effected  in  them  by  what  may  be  termed  the  mechanism  of  their 
nervous  centres,  and  that  less  is  left  to  voluntary  choice  and  direction,  which 
can  only  be  safely  trusted  where  a  considerable  amount  of  Intelligence  exists  to 
guide  it.  That  the  existence  of  even  the  most  perfectly  adapted  combination  of 
different  muscular  actions,  all  obviously  bearing  upon  a  definite  object,  does  not 
in  itself  justify  the  attributing  this  combination  to  a  design  or  voluntary  choice 

thological  portion  of  the  Hunterian  Museum  drawn  up  by  Mr.  Paget),  there  was  the  re- 
cord of  a  case  of  paraplegia,  in  which  it  appeared  that  Hunter  had  witnessed  reflex  move- 
ments of  the  legs  in  which  sensation  did  not  participate.  When  the  patient  was  asked 
whether  he  felt  the  irritation  by  which  the  motions  were  excited,  he  significantly  replied — 
glancing  at  his  limbs — "  No,  Sir,  but  you  see  my  legs  do." 
1  [Phil.  Med.  Examiner,  N.  S.  vol.  viii.  No.  xcii.  p.  482.] 


676  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

in  the  individual  that  executes  it,  is  sufficiently  proved  by  the  existence  of  such 
a  combination  in  various  automatic  movements,  most  essential  to  the  mainte- 
nance of  the  organic  functions,  which  are  performed  with  the  utmost  regularity, 
not  only  without  our  bestowing  any  volitional  effort  upon  them,  but  also  under 
circumstances  which  indicate  that  not  even  our  consciousness  has  any  share  in 
developing  or  directing  them.  Such  are  the  ordinary  and  extraordinary  move- 
ments of  Respiration,  the  movements  of  Deglutition  and  Defecation,  &c. 

710.  Medulla  Oblongata. — The  cranial  prolongation  of  the  Spinal  cord, 
which  is  distinguished  by  this  appellation,  has  been  regarded  by  some  Physiolo- 
gists as  the  peculiar  seat  of  vitality  ;  since,  although  the  other  Encephalic  masses 
may  be  withdrawn  from  above,  and  nearly  the  whole  of  the  Spinal  Cord  may 
be  removed  from  below,  without  the  destruction  of  life,  yet  a  complete  stop  is 
put  to  the  current  of  vital  action  when  the  Medulla  Oblongata  is  destroyed. — 
[The  arrest  of  vital  action  does  not  take  place  in  frogs,  or  in  other  animals 
that  respire  largely  by  the  general  surface,  as  for  instance  amphibia  and  reptilia, 
for  in  them  life  continues  for  weeks,  or  even  months,  after  complete  removal  of 
the  Medulla  Oblongata;  circulation,  digestion,  and  secretion  going  on  with  an 
activity  but  little  impaired;  death  finally  occurring  from  the  diminution  of  the 
respiratory  functions.1 — ED.]  But  the  dependence  of  the  vital  activity  of  the 
body  generally  upon  the  functional  integrity  of  this  part  of  the  nervous  system 
is  simply  consequent  upon  the  fact  that  the  Medulla  Oblongata  contains  the  gan- 

Fig.  176.  Fig.  177. 


Anterior  view  of  the  medulla  ob-  Posterior  view  of  the  medulla  oblongata :  pp.  Posterior  pyra. 

longata:    p,   p.   Pyramidal    bodies,  mids,    separated    by    the    posterior    fissure.      rr.   Restiform 

decussating  at  d.    o,  o.  Olivary  bo-  bodies,  composed  of   cc,  posterior  columns,    and   dd,    lateral 

dies,     r,  r.  Restiform  bodies,     a,  a.  part  of  the  antero-lateral   columns  of  the   cord.    aa.  Olivary 

Arciform  fibres,    v.  Lower  fibres  of  columns,  as  seen  on  the  floor  of  the  fourth  ventricle,  separated 

the  Pons  Varolii.  by  «,  the  median  fissure,  and  crossed  by  some  fibres  of  origin  of 

nn,  the  seventh  pair  of  nerves. 

glionic  centre  of  the  Respiratory  movements;  upon  the  continuance  of  which,  as 
already  shown  (CHAP.  x.  SECT.  3),  the  continuance  of  the  Circulation  is  depend- 
ent, and,  with  this,  the  maintenance  of  the  Organic  functions  generally.  In  no 
other  essential  respect  does  the  Medulla  Oblongata  differ  from  the  Medulla  Spi- 
nalis  than  in  its  ministration  to  certain  classes  of  reflex  movements  which  are 

1  [Vide  Phil.  Med.  Examiner,  N.  S.,  Vol.  viii.,  No.  xcii.,  in  which  will  be  found  an  ac- 
count of  the  experiments  of  Dr.  13rown-Se"quard  upon  this  subject.] 


THE   SPINAL   CORD. 


677 


Fig.  178. 


specially  destined  to  afford  the  conditions  requisite  for  the  performance  of  the 
functions  of  Respiration  and  Deglutition,  instead  of  exerting  its  reflex  power  in 
the  ordinary  locomotive  actions  of  the  body;  but  the  arrangement  of  its  fibrous 
strands  and  of  its  nuclei  of  gray  matter  is  peculiar ;  and  a  brief  notice  of  its 
structure,  and  of  the  connections  of  its  parts,  is  consequently  desirable. — Four 
principal  strands  of  nerve-fibres  may  be  distinguished  in  each  of  its  lateral 
halves;  these  are — I.  The  Anterior  Pyramids  or  Corpora  Pyramidalia ; — 
n.  The  Olivary  Bodies,  or  Corpora  Olivaria;  in.  The  Restiform  Bodies,  or 
Corpora  Restiformm  /  otherwise  called  Processus  a  Cerebello  ad  Medullam 
Oblongatam;  iv.  The  Posterior  Pyramids,  or  Corpora  Pyramidalia  Pos- 
terwra. — The  connections  of  these  with  the  Brain  above,  and  with  the  Spinal 
Cord  below,  will  be  presently  traced.1  The  vesicular  substance,  on  the  other 
hand,  is  principally  aggregated  in  three  pairs  of  ganglionic  centres;  of  which 
the  anterior  forms  the  nucleus  of  the  Olivary  body,  the  lateral  of  the  Restiform, 
and  the  posterior  of  the  Posterior  Pyramidal. 

711.  The  Anterior  Pyramids  (i)  consist  entirely  of  fibrous  structure,  and 
establish  a  communication  be- 
tween the  "  motor  tract"  (Fig. 
178,  m  t)  of  the  Crura  Cerebri, 
and  the  anterior  and  antero- 
lateral  columns  of  the  Spinal 
Cord.  The  principal  part  of 
their  fibres  decussate ;  and  these, 
as  they  pass  from  above  down- 
wards, dip  away  from  the  ante- 
rior surface  of  the  Cord,  and 
connect  themselves  with  its  mid- 
dle or  lateral  columns,  instead 
of  with  its  anterior,  as  was 
pointed  out  by  Rosenthal,2  and 
more  fully  described  by  Dr. 
J.  Reid.3  A  small  part  of  the 
fibres  of  the  pyramidal  columns, 
however,  do  not  decussate,  but 
proceed  downwards  on  the  same 
side,  into  the  corresponding  an- 
terior columns  of  the  Spinal 
Cord.  ii.  The  Olivary  bodies 
are  composed  of  fibrous  strands, 
enclosing  a  gray  nucleus  (Fig. 
178,  off)  on  either  side.  The 
upward  continuation  of  the  for- 


Dissectionof  the  Medulla  Oblongata,io  show  the  connections 
of  its  several  strands :  A,  corpus  striatum ;  B,  thalamus  op- 
ticus;  c,  D,  corpora  quadrigcmina;  E,  commissure  connect- 
ing them  with  the  cerebellum ;  F,  corpora  restifonnia ;  P,  P, 
pons  varolii;  st,  st,  sensory  tract;  mt,  mt,  motor  tract;  g, 
olivary  tract ;  p,  pyramidal  tract;  oy,  olivary  ganglion;  op, 
optic  nerve ;  3  m,  root  of  the  third  pair  (motor) ;  5  «,  sensory 
root  of  the  fifth  pair. 


1  Great  diversities  will  be  found  in  the  accounts  given  of  those  connections  by  different 
authors ;    some  of  which  are  attributable  to  a  variation  in  the  use  of  terms,  which  must 
not  pass  unnoticed.     By  the  majority  of  Anatomists,  the  name  of  Corpora  Restiformia  is 
given  to  the   Cerebellar  Columns ;  and  this  designation,  therefore,  it  seems  advisable  to 
retain.     Some,  however,  and  amongst  them  Dr.  J.  Reid,  in  his  very  excellent  description 
of  the  Anatomy  of  the  Medulla  Oblongata  ("Edinb.  Med.  and  Surg.  Journal,"  Jan.  1841), 
give  that  name  to  the  columns  that  pass  up  from  the  posterior  division  of  the  spinal  cord 
into  the  crus  cerebri — which  are  here  called  (after  Sir  C.  Bell)  the  posterior  pyramids ; 
and  apply  the  term  Posterior  Pyramids  to  the  Cerebellar  column.     The  truth  is  that,  as 
Sir  C.  Bell  has  justly  observed,  all  the  tracts  of  fibrous  matter  connecting  the  Brain  with 
the  Spinal  Cord  have  a  somewhat  pyramidal  form ;  and  it  might  be  added  that  all  have 
something  of  a  restiform  or  cord-like  aspect. 

2  "Ein  Beitrag  zur  Encephalatomie,"  Weimar,  1815. 

3  "Edinb.  Med.  and  Surg.  Journ.,"  Jan.  1841 ;  and  "Physiol.,  Pathol.,  and  Anat.  Re- 
searches," CHAP.   VII. 


678 


OF  THE  FUNCTIONS  OF  THE  NERVOUS  SYSTEM. 


mer  divides,  while  passing  through  the  Pons  Varolii,  into  two  bands,  one  of 
which  proceeds  upwards  and  forwards  as  a  part  of  the  "motor  tract"  (m  t)  of 
the  Crus  Cerebri,  whilst  the  other  (o)  proceeds  upwards  and  backwards  to  reach 
the  Corpora  Quadrigemina  (c,  D).  The  olivary  columns  are  continuous  in- 
feriorly  with  the  anterior  columns  of  the  Spinal  Cord;  and  afford  attachments 
to  the  anterior  roots  of  the  1st  and  2d  cervical  nerves.  The  vesicular  nucleus, 
which  is  known  as  the  corpus  dentatum,  seems  to  be  especially  connected  with 
the  origins  of  the  nerves  concerned  in  the  regulation  of  the  movements  of  the 
tongue;  thus  we  find  that  anteriorly  a  portion  of  the  roots  of  the  Hypoglossal, 
which  is  the  motor  nerve  of  the  tongue,  issue  from  it;  whilst  posteriorly  a  por- 
tion of  the  roots  of  the  Grlosso-pharyngeal,  which  is  one  of  the  sensory  nerves 
of  that  organ,  seem  to  terminate  in  it. — m.  The  Restiform  bodies,  in  like 
manner,  each  consist  of  fibrous  strands  (F)  inclosing  a  gray  nucleus.  The 

Fig.  179. 


Transverse  section  of  the  medulla  oblongata  through  the  lower  third  of  the  olivary  hodiee.  (From  Stilling.) 
Magnified  4  diameters. 

a.  Anterior  fissure,  b.  Fissure  of  the  calamus  scriptorius.  c.  Raphe.  d.  Anterior  columns,  e.  Lateral 
columns,  f.  Posterior  columns,  g.  Nucleus  of  the  hypoglossal  nerve,  containing  large  vesicles,  h.  Nu- 
cleus of  the  vagus  nerve,  i,  t.  Gelatinous  substance,  k,  fc.  Roots  of  the  vagus  nerve.  I.  Roots  of  the 
hypoglossal,  or  ninth  nerve,  m.  A  thick  bundle  of  white  longitudinal  fibres  connected  with  the  root  of  the 
vagus.  «.  Soft  column  (Zartstrang,  Stilling),  o.  Wedge-like  column  (Keelstrang,  Stilling),  p.  Transverse 
and  arciform  fibres,  q.  Nucleus  of  the  olivary  bodies,  r.  The  largo  nucleus  of  the  pyramid,  s,  s,  s.  The 
small  nuclei  of  the  pyramid,  u.  A  mass  of  gray  substance  near  the  nucleus  of  the  olives  (Oliven-N(t>erikerri)« 
u,  q,  r,  are  traversed  by  numerous  fibres  passing  in  a  transverse  semicircular  direction,  v,  w.  Arciform 
fibres,  x.  Gray  fibres. 

fibrous  strands  pass  upwards  into  the  Crura  Cerebelli;  whilst  below  they  are 
chiefly  continuous  with  the  posterior  columns  of  the  Spinal  Cord,  having  also 
some  connection  with  the  posterior  part  of  the  middle  columns.  These  Cere- 
bellar  columns  also  communicate,  however,  with  the  anterior  columns  of  the 


MEDULLA   OBLONGATA. 


679 


Spinal  Cord,  by  a  band  of  "arciform"  fibres,  whose  connections  were  first  dis- 
tinctly described  by  Mr.  Solly;1  of  these  there  is  a  superficial  set  which  unites 
itself  with  the  pyramidal  columns,  and  a  deep  set  which  comes  into  relation 
with  the  olivary.  Their  gray  nucleus,  or  "restiform  ganglion,"  appears  to  be 
the  ganglionic  centre  of  the  Pneumogastric  nerves,  and  of  a  portion  of  the  roots 
of  the  Glosso-pharyngeal.  iv.  The  Posterior  Pyramids  are  scarcely  distin- 

Fig.  180. 


' 


Course  of  the  Motor  tract,  according  to  Sir  C.  Bell.— A,  A,  fibres  of  the  Hemispheres,  converging  to  form 
the  anterior  portion  of  the  crus  cerebri ;  B,  the  same  tract,  where  passing  the  crus  cerebri ;  c,  the  right  Pyra- 
midal body,  a  little  above  the  point  of  decussation ;  D,  the  remaining  part  of  the  Pons  Varolii,  a  portion  hav- 
ing been  dissected  off  to  expose  B. — 1,  olfactory  nerve,  in  outline ;  2,  union  of  optic  nerves ;  3,  3,  motor 
oculi;  4,  4,  patheticus;  5,  5,  trigeminus;  6,  6,  its  muscular  division;  7,  7,  its  sensory  root;  8,  origin  of 
sensory  root  from  the  posterior  part  of  the  medulla  oblongata;  9,  abducens  oculi ;  10,  auditory  nerve;  11, 
facial  nerve;  12,  eighth  pair;  13,  hypoglossal;  14,  spinal  nerves ;  15,  spinal  accessory  of  right  side,  separated 
from  par  vagum  and  glosso-pharyngeal. 


'Philosophical  Transactions,"  1836. 


OF  THE  FUNCTIONS  OF  THE  NERVOUS  SYSTEM. 

guishable  externally  from  the  Restiforrn  bodies,  of  which  they  were  formerly 
described  as  a  constituent  part;  they,  however,  form  the  immediate  boundaries 
of  the  posterior  median  fissure;  and  whilst  superficially  marked-off  from  the 
E-estiform  bodies  by  a  slight  groove,  are  more  completely  separated  from  them 
by  their  anatomical  relations  to  the  parts  above  and  below.  Their  fibres  estab- 
lish a  connection  between  the  sensory  tract  (Fig.  178,  st,  st)  of  the  Crura 
Cerebri,  and  the  posterior  part  of  the  lateral  columns  of  the  Spinal  Cord,  some 
of  them  passing  also  into  its  posterior  columns.  These  fibrous  tracts  are  stated 
by  Mr.  Solly1  and  Dr.  Radclyfie  Hall3  to  decussate,  partially  at  least,  whilst 
passing  through  the  Pons  Varolii.3  The  gray  nuclei  of  the  Posterior  Pyramids, 
situated  immediately  beneath  the  "fourth  ventricle"  (which  is  nothing  else 
than  the  space  left  by  the  divergence  of  the  Restiform  and  Posterior  Pyramidal 
tracts),  are  the  ganglionic  centres  of  the  Auditory  nerves,  or  the  proper  Audi- 
tory ganglia;  and  it  is  interesting  to  observe  that  their  seat  precisely  corre- 
sponds with  that  of  the  rudimental  organ  of  hearing  in  many  Invertebrata. 

712.  The  Medulla  Oblongata  is  usually  considered  as  terminating   at  the 
lower  border  of  the  Pons  Varolii ;  but  it  will  be  convenient  here  to  trace  up- 

Fig.  181. 


Course  of  the  Sensory  tract  according  to  Sir  C.  Bell.— A,  Pons  Varolii ;  B,  u,  sensory  tract  separated ;  c,  union 
of  posterior  columns;  D,  D,  posterior  roots  of  spinal  nerves  ;  E,  sensory  roots  of  fifth  pair. 

wards  the  strands  by  which  it  is  connected  with  the  higher  Encephalic  centres, 
as  a  clearer  idea  of  its  anatomical  and  physiological  relations  will  thus  be  ob- 
tained.— The  Pons  is  chiefly  composed  of  transverse  fibres  which  constitute  the 
great  commissure  of  the  Cerebellum ;  and  these  fibres  not  only  surround  the 

1  "The  Human  Brain,"  2d  edit.,  p.  243. 

2  "Edinb.  Med.  and  Surg.  Journ.,"  July,  1847,  Plate  vn. 

3  A  decussation  of  the  Posterior  Pyramids  was  described  by  Sir  C.  Bell  as  occurring  at 
the  same  level  with  the  decussation  of  the  Anterior  Pyramids  (Fig.  133,  c) ;  there  can  be 
no  doubt,  however,  that  this  is  an  error,  which  probably  originated  in  his  having  misin- 
terpreted the  appearance  presented  by  the  posterior  aspect  of  the  anterior  decussation. 


THE   SPINAL   CORD.  681 

longitudinal  bands  which  connect  the  Cerebral  mass  with  the  Spinal  Cord,  but 
pass  through  them ;  so  as  in  some  degree  to  isolate  the  two  lateral  halves 
from  one  another,  and  to  form  a  complete  'septum  between  the  anterior  and 
posterior  portions  of  each.  These  anterior  and  posterior  tracts  of  the  Crura 
Cerebri  are  respectively  subservient  to  the  motor  and  the  sensory  functions;  as 
is  clearly  indicated  by  the  endowments  of  the  nerves  which  are  connected 
with  each.1  The  Motor  tract  is  brought  into  view,  by  simply  raising  the  super- 
ficial layer  of  the  Pons,  and  tracing  upwards  and  downwards  the  longitudinal 
fibres  which  present  themselves.  It  is  then  found  that  these  fibres  may  be 
traced  upwards  into  the*Corpora  Striata ;  and  downwards  into  the  Anterior  Pyra- 
mids and  a  portion  of  the  Olivary  columns ;  so  that  they  connect  the  Corpora 
Striata  with  the  anterior,  and  with  the  anterior  portion  of  the  lateral  columns 
of  the  Spinal  Cord.  With  this  tract  we  find  connected — passing  from  below 
upwards — the  roots  of  the  Spinal  Accessory,  the  Hypoglossal,  the  Facial  or 
Portio  Dura  of  the  7th,  the  6th  or  Abducens  oculi,  the  smaller  root  of  the  5th 
(which  can  be  traced  to  the  part  of  the  Olivary  column  that  passes  upwards  to 
the  Corpora  Quadrigemina),  the  4th  or  Trochlearis  (which  is  attached  to  the 
same  part  of  the  tract),  and  the  3d  or  Oculo-rnotor  nerves ;  all  of  which  are 
purely  motor  in  their  endowments.  The  Sensory  tract  is  displayed  by  opening 
the  Medulla  Oblongata  on  its  posterior  aspect ;  and  then  separating  and  turning 
aside  the  Restiform  columns,  so  as  to  bring  into  view  the  posterior  pyramids. 

[Fig.  181*. 


;y 

SO 


The  whole  of  the  pyramidal  and  olivary  bodies  and  their  respective  tracts  have  been  removed,  and  the 
posterior  part  of  the  cord  left.  D  P.  Decussation  of  the  pyramidal  bodies.  D  s.  Decussation  of  the  cerebral 
sensory  tract,  or  posterior  third  of  the  antero-lateral  column,  i  &  c.  Inter-cerebral  commissure  divided.  K. 
Posterior  extremity  of  the  thalamus  nervi  bptici.  K  A-.  Divided  end  of  the  same.  g.  Corpus  geniculatum 
externum.  u.  Crus  cerebri.  u  u.  Divided  end  of  the  same,  w  w.  Corpora  restiformia.  c.  Third  pair  of 
nerves,  c  a.  Corpora  albicantia.  e  s.  Sensory  root  of  the  fifth  pair.  I  n.  Locus  niger.  s  t.  Cerebral  sensory 
tract,  p  v.  Dotted  lines  marking  the  situation  and  width  of  the  pons  Varolii,  behind  which  the  decussation 
takes  place.] 

1  This  was  first  clearly  shown  by  Sir  C.  Bell  in  the  "Philos.  Transact,"  1835. 


682 


OF  THE  FUNCTIONS  OF  THE  NERVOUS  SYSTEM. 


Its  fibres  may  be  traced  upwards  into  the  Thalanri  Optici ;  whilst  they  pass 
through  the  Posterior  Pyramids  into  the  posterior  portion  of  the  lateral  col- 
umns, and  also  into  the  posterior  columns  of  the  Spinal  Cord.  With  this  tract 
are  connected  nearly  the  whole  of  the  roots  of  the  Pneumogastric  and  Glosso- 
pharyngeal  nerves,  and  the  larger  or  sensory  root  of  the  5th  pair.  The  greater 
part  of  the  motor  tract  decussates  where  the  Anterior  Pyramids  become  conti- 
nuous with  the  lateral  columns  of  the  Spinal  Cord;  on  the  other  hand,  the 
greater  part  of  the  Sensory  tract  decussates  in  its  passage  through  the  Pons 
Varolii  [Fig.  181*].  The  following  tabular  view  may  assist  in  conveying  a 

Fig.  182. 


A  plan  of  the  branches  of  the  fifth  nerve,  modified  from  a  sketch  by  Sir  C.  Bell.  a.  Submaxillary  gland, 
•with  the  submaxillary  ganglion  above  it.  1.  Small  root  of  the  fifth  nerve,  which  joins  the  lower  maxillary 
division.  2.  Larger  root,  with  the  Gasserian  ganglion.  3.  Ophthalmic  nerve.  4.  Upper  maxillary  nerve.  5. 
Lower  maxillary  nerve.  6.  Chorda  tympani.  7.  Facial  nerve. 

knowledge  of  this  somewhat  intricate  piece  of  Anatomy ;  which,  when  once 
mastered,  will  be  found  to  be  really  simpler  than  it  appears. 


SPINAL  CORD.  MEDULLA  OBLONGATA. 

Antwior  or  Motor  Division, 
f  Arciform  fibres  of  Olivary  and  Anterior  Pyramidal 


BRAIN. 


columns   ..... 

.    .     .      n  ,  I  Posterior  portion  of  Olivary  columns 

Anterior  Columns   j  Anterior  portion  of  ()livary  colllmna 


Cerebellum. 
Corpora  Quadrige- 
1      mina. 


I  Non-decussating  portion  of  Anterior  Pyramidal  I 


columns 


Anterior  portion  of  f  Decussating  portion  of  Anterior  Pyramidal  col- 
Lateral  Columns  \      umns 


\-  Corpora  Striata. 


. 


CEPHALIC   NERVES. — FIFTH   PAIR,    OR   TRIGEMINUS.  683 

SPINAL  CORD.  MEDULLA  OBLONGATA.  BRAIN. 

Posterior  or  Sensory  Division. 

Posterior    portion  f  Decussating  portion  (?)  of  Posterior  Pyramidal  "j 
of  Lateral  Columns  \      columns L  Thalami  Optici 

{Non-decussating  portion  (?)  of  Posterior  Pyra-  j 
midal  columns           .....       J 
Restiform  columns Cerebellum. 

713.  Nerves  of  the  Spinal  Axis. — With  the   Spinal  Cord  (in  its  limited 
sense)   there  are  connected  thirty-one  pairs  of  nerves ;    each  of  these  corre- 
sponding to  a  vertebral  segment  of  the  body,  and  having  a  double  set  of  roots, 
as  already  described  (§  696).     The  anterior  roots  are  usually  the  smaller ;  and 
this  is  particularly  the  case  with  those  of  the  cervical  nerves,  in  which  the  pos- 
terior roots  are  of  remarkable  comparative  size.     In  the  first  Cervical  "  or  sub- 
occipital"  pair,  the  anterior  roots  are  sometimes  wanting;  but  there  is  then  a 
derivation  of  fibres  from  the  Spinal  Accessory,  or  from  the  Hypoglossal,  or  from 
both.     The  two  roots  of  the  ordinary  Spinal  nerves  unite  immediately  beyond 
the  ganglion,  which  is  situated  on  the  posterior  one ;  and  the  trunk  thus  formed 
separates   immediately  into  two  divisions — the   anterior  and  posterior — each 
of  which  contains  both  afferent  and  motor  fibres.     These  divisions,  of  which 
the  anterior  is  by  far  the  larger,  proceed  to  the  anterior  and  posterior  parts  of 
the  body  respectively ;  and  are  chiefly  distributed  to  the  skin  and  the  muscles. 
The  anterior  branch  is  that  which  communicates  with  the  Sympathetic  nerve. 
In  addition  to  these,  however,  the  cranial  prolongation  of  the  Spinal  Axis  is  the 
centre  of  all  the  cephalic  nerves,  save  those  of  special  sensation,  which  termi- 
nate in  their  respective  ganglia ;  and  as  these  cephalic  nerves  are  for  the  most 
part  distinguished  by  the  peculiarity  of  their  endowments,  they  require  to  be 
separately  noticed. 

714.  The  pair  of  nerves  commonly  designated  as  the  Fifth  of  the  Cephalic 
series,   or  as  the    Trigeminus,   is  the  one   which  more  nearly  resembles   the 
ordinary  Spinal  nerves   (as  was  long  since  pointed  out  by  Sir  C.  Bell),  than 
does  any  other  of  those  originating  within  the  cranium.     It  possesses  two  dis- 
tinct sets  of  roots,  of  which  one  is  much  larger  than  the   other  ;  on  the  larger 
root,  as  on  the  posterior  and  larger  root  of  the  Spinal  nerves,  is  a  distinct  gan- 
glion ;  and  the  fibres  arising  from  the  smaller  root  do  not  blend  with  the  others, 
until  after  the  latter  have  passed  through  this  ganglion.     The  trunk  of  the 
nerve  separates,  as  is  well  known,  into  three  divisions — the   Ophthalmic,  the 
Superior  Maxillary,  and  the  Inferior  Maxillary ;  and  it  can  be  easily  shown,  by 
careful  dissection,  that  the  fibres  of  the  smaller  root  pass  into  the  last  of  these 
divisions  alone.     When  the 'distribution  of  this  nerve  is  carefully  examined,  it 
is  found  that  the  first  and  second  divisions  of  it  proceed  almost  entirely  to  the 
skin  and  mucous  surfaces,  only  a  very  small  proportion  of  their  fibres  being 
lost  in  the  muscles ;  whilst  of  the  branches  of  the  third  division,  a  large  num- 
ber are  distinctly  muscular.     Hence  analogy,  and  the  facts  supplied  by  anatomi- 
cal research,  would  lead  to  the  conclusion  that  the  first  two  divisions  are  nerves 
of  sensation  only,  and  that  the  third  division  combines  sensory  and  motor 
endowments.     Such  an  inference  is  fully  borne  out  by  experiment.     When  the 
whole  trunk  is  divided  within  the  cranium  by  the  penetration  of  a  sharp  instru- 
ment (which  Magendie,  by  frequent  practice,   has  been  able  to  accomplish), 
evident  signs  of  acute  pain  are  given.     After  the  incision   has    been  made 
through  the  skin,  the  animal  remains  quiet  until  the  nerve  is  touched ;  and 
when  it  is  pressed  or  divided,  doleful  cries  are  uttered,  which  continue  for  some 
time,  showing   the  painful  effect  of  the  irritated  state   of  the  cut  extremity. 
The  common  sensibility  of  all  the  parts  supplied  by  this  nerve  is  entirely 
destroyed  on  the  affected  side.     The  jaw  does  not  hang  loosely,  because  it  is 


684 


OF  THE  FUNCTIONS  OF  THE  NERVOUS  SYSTEM. 


partly  kept  up  by  the  muscles  of  the  other  side;  but  it  falls  in  a  slight  degree; 
and  its  movements  are  seen,  when  carefully  observed,  to  be  somewhat  oblique. 
If  the  trunk  be  divided  on  each  side,  the  whole  head  is  deprived  of  sensibility, 
and  the  animal  carries  it  in  a  curious  vacillating  manner,  as  if  it  were  a 
foreign  body.  If  the  anterior  or  Ophthalmic  branch  only  be  divided,  all  the 
parts  supplied  by  it  are  found  to  have  lost  their  sensibility,  but  their  motions 
are  unimpaired  ;  and  all  experiments  and  pathological  observations  concur  in 
attributing  to  it  sensory  endowments  only.  The  only  apparent  exception  is  in 

the  case  of  the  naso-ciliary  branch, 

Fig.  183.  since  there  is  good  reason  to  be- 

lieve that  the  long  root  of  the  cili- 
ary ganglion  and  the  long  ciliary 
nerves  possess  motor  powers  ;  but 
these  appear  to  be  derived  from 
the  Sympathetic  or  from  the  3d 
pair.  When  the  whole  nerve,  or 
its  anterior  branch,  is  divided  in 
the  rabbit,  the  pupil  is  exceedingly 
contracted,  and  remains  immova- 
ble ;  but  in  dogs  and  pigeons  it  is 
dilated.  The  pupil  of  the  other 
eye  is  scarcely  affected  ;  or,  if  its 
dimensions  be  changed,  it  soon  re- 
turns to  its  natural  state.  The 
eyeball,  however,  speedily  becomes 
inflamed;  and  the  inflammation 

Usually  runs  OU  to  Suppuration  and 
complete  disorganization.  The 

commencement   of   these  changes 

r  i  •  •       i        «,i  • 

^   ^    Commonly   noticed    Wlthm 

twenty-four  hours  after  the  Opera- 
tion  ;  and  they  appear  to  be  due 
to  the  Want  of  the  protective  SCCre- 

tion,  which  (as  will  be  explained 

when  the  direct  influence  of  the  nervous  system  upon  the  organic  functions  is 
considered)  is  necessary  to  keep  the  mucous  surface  of  the  eye  in  its  healthy 
condition,  and  which  is  not  formed  when  the  sensibility  of  that  surface  is 
destroyed.  The  Superior  Maxillary  branch,  considered  in  itself,  is  equally 
destitute  of  motor  endowments  with  the  ophthalmic  ;  but  its  connections  with 
other  nerves,  through  the  spheno-palatine  ganglion  and  its  anastomosing  twigs, 
may  introduce  a  few  motor  fibres  into  it.  The  Inferior  Maxillary  branch  is 
the  only  one  which  possesses  motor  as  well  as  sensory  endowments  from  its 
origin;  but  its  different  subdivisions  possess  these  endowments  in  varying 
proportions,  some  being  almost  exclusively  motor,  and  others  as  completely  of 
a  sensory  character.  The  latter  is  probably  the  nature  of  the  Lingual  branch  ; 
and  there  seems  good  reason  to  believe,  as  will  hereafter  be  shown  (§  717), 
that  this  ministers  not  only  to  the  tactile  sensibility  of  the  tongue,  but  to  the 
sense  of  Taste.  The  muscles  put  in  action  by  this  division  are  solely  those 
concerned  in  the  masticatory  movements.  The  5th  pair  is  connected  in  differ- 
ent parts  of  its  course,  with  a  number  of  small  ganglia  belonging  to  the  Sym- 
pathetic system.  One  of  the  most  interesting  of  these  ganglia  is  the  Ophthal- 
mic or  Ciliary  (Fig.  183),  which  is  the  centre  whence  the  eyeball  derives  its 
supply  of  nerves,  sensory,  motor,  and  sympathetic.  This  ganglion  derives  its 
sensory  fibres  by  its  "  long  root"  from  the  nasal  branch  of  the  Ophthalmic  divi- 
sion of  the  5th  pair;  its  motor  fibres,  by  the  "short  root,"  from  the  3d  pair; 


A  representation  of  some  of  the  nerves  of  the  orbit,  espe- 
cially  to  show  the  lenticular  ganglion  (Arnold).    1.  Gan- 

giion  of  the  fifth.  2.  ophthalmic  nerve.  3.  Upper  maxii- 

lary.  4.  Lower  maxillary.  5.  Nasal  hranch,  giving  the 
iJg  root  to  the  lenticular  ganglion.  6.  Third  nerve.  %! 
Inferior  oblique  branch  of  the  third  connected  with  the 
ganglionbythesfcortrarf.  8.  Optic  nerve.  9.  Sixth  nerve, 
10.  Sympathetic  on  the  carotid  artery. 


CEPHALIC    NERVES.  —  THIRD,    FOURTH,    AND    SIXTH.  685 

whilst  by  another  small  root  it  is  connected  with  the  cavernous  plexus  of  the 
Sympathetic  system :  thus  presenting  a  sort  of  miniature  representation  of  the 
entire  series  of  Sympathetic  ganglia,  and  of  their  connections  with  the  Cerebro- 
spinal  system.1 

715.  The  Third,  Fourth,  and  Sixth  pairs,  together  make  up  the  apparatus 
of  motor  nerves,  by  which  the  muscles  of  the  Orbit  are  called  into  action.     The 
3d  pair  supplies  the  greater  number  of  the  muscles ;  the  4th  being  confined  to 
the  Superior  Oblique,  and  the  6th  to  the  External  Rectus.     Of  these  nerves, 
the  3d  pair  is  the  only  one  which  exhibits  any  appearance  of  sensibility,  when 
its  trunk  is  irritated;  but  this  sensibility  is  not  nearly  so  great  as  that  of  the 
5th  pair;  and  as  there  is  no  reason  to  believe  that  it  is  really  possessed  by  the 
3d  in  virtue  of  its  direct  connection  with  the  nervous  centres,  it  is  probably 
imparted  by  the  anastomosis  of  that  nerve  with  the  5th — some  filaments  of 
which  may  pass  backwards  as  well  as  forwards,  so  as  to  confer  sensibility  on  the 
trunk  of  the  3d,  above  as  well  as  beyond  their  point  of  entrance. — The  peculiar 
mode  in  which  those  motor  nerves  ordinarily  excite  the  muscles  to  action,  under 
the  guidance  of  the  visual  sense,  will  be  considered  in  the  next  Section.    Although 
commonly  ranked  as  cephalic  nerves,  they  have  no  direct  connection  with  the 
Cerebrum;  their  real  origin  being  from  the  upper  part  of  the  Spinal  Axis  (§  712). 
The  roots  of  the  third  pair  may  be  traced  into  direct  connection  with  the  Corpora 
Quadrigemina ;  a  fact  of  considerable  physiological  importance,  as  will  hereafter 
appear. — The  chief  actions  of  a  purely  reflex  nature,  to  which  this  group  of 
nerves  ordinarily  ministers,  are  the  government  of  the  diameter  of  the  pupil, 
which  is  accomplished  through  the  Third  pair ;   and  the  rolling  of  the  eyeball 
beneath  the  upper  lid  during  sleep,  as  well  as  in  the  efforts  of  sneezing,  cough- 
ing, &c.     But  irregular  movements  of  the  eyeballs,  which  must  be  referred  to 
the  same  group,  are  continually  seen  to  accompany  various  other  forms  of  con- 
vulsive action. 

716.  The  Portio  Dura  of  the  Seventh  pair,  or  facial  nerve,  has  been  con- 
sidered, since  the  first  researches  of  Sir  C.  Bell,  to  be  a  nerve  of  motion  only ; 
but  some  physiologists  have  maintained,  that  it  both  possesses  sensory  endow- 
ments, and"  arises  by  a  double  root.     According  to  Yalentin,  however,  who 

1  The  functions  of  this  ganglion  have  been  made  the  subject  of  particular  investiga- 
tion by  Dr.  C.  Radclyffe  Hall  ("Edinb.  Med.  and  Surg.  Journal,"  1846-48),  whose  most 
important  results  are  as  follows : — 

1.  The  size  of  the  ciliary  ganglion  is  always  in  direct  proportion  to  the  activity  of  the 
iris,  which  in  turn  always  bears  a  direct  relation  to  the  strength  and  acuteness  of  vision, 
and  to  the  nocturnal  habits  of  the  animal,  and  implies  a  proportionate  development  of  the 
internal  vascular  apparatus  of  the  eye. 

2.  The  ganglion  is  always  more  intimately  connected  with  the  3d  pair  than  with  any 
other,  the  size  of  the  short  root  being  always  in  direct  relation  to  that  of  the  ganglion ; 
and  the  ganglion  being  sometimes  a  mere  swelling  on  the  trunk  of  the  nerve. 

3.  The  fibres  derived  from  the  5th  pair  do  not  terminate  in  the  ganglion,  but  pass  on- 
wards through  it  to  the  ciliary  plexus. 

4.  In  the  Rabbit,  the  iris  receives  fibres  from  the  6th  pair,  which  do  not  pass  through 
the  ganglion  ;  and  it  is  through  this  that  the  contraction  of  the  pupil  is  produced  in  that 
animal  by  irritation  of  the  5th  pair,  which  will  not  produce  any  efi°ect  upon  the  pupil  of 
the  Dog,  Cat,  or  Pigeon,  so  long  as  it  does  not  affect  the  brain  to  the  extent  of  producing 
vertigo,  nor  affect  the  visual  sense  in  any  other  way. 

5.  Irritation  of  the  5th  nerve  does  not  in  any  animal  affect  the  action  of  the  iris  after 
the  division  of  the  cerebral  connections  of  all  the  other  ocular  nerves ;  so  that  its  influ- 
ence over  the  movements  of  the  iris  must  be  reflected  through  the  encephalic  centres,  not 
through  the  ophthalmic  ganglion. 

6.  The  function  of  the  ganglionic  centre  itself,  as  a  part  of  the  Sympathetic  system, 
is  to  bring  the  "  organic  actions"  of  the  eyeball,  especially  its  supply  of  bloqd,  into  har- 
mony with  its  functional  activity ;  this  harmony  being  produced  by  the  passage  of  the 
cerebro-spinal  nerves  through  the  ganglion,  which  excites  the  synergetic  action  of  its  own 
vesicles  and  nerve-fibres. 


686  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

experimented  on  the  roots  exposed  within  the  cranium,  it  possesses  no  sensory 
endowments  at  its  origin;  since,  when  these  roots  were  touched,  the  animals 
gave  no  signs  of  pain,  though  violent  muscular  movements  were  excited  in  the 
face.  Subsequently  to  its  first  entrance  into  the  canal  by  which  it  emerges, 

Fig.  184. 


>*» 


The  Nerves  of  the  OrUt  seen  from  the  outer  side:  after  Arnold.—!.  Section  of  the  frontal  bone;  imme. 
diately  behind  the  numeral  is  the  frontal  sinus,  and,  in  front,  the  integument.  2.  The  superior  maxillary 
bone ;  the  section  in  front  of  the  numeral  exhibits  the  maxillary  sinus.  3.  Part  of  the  sphenoid  bone.  4.  The 
levator  palpebrae  and  superior  rectus  muscles.  5.  The  superior  oblique  muscle.  6.  The  inferior  oblique 
muscle.  7.  The  ocular  half  of  the  external  rectus  muscle  drawn  forwards.  8.  The  orbital  half  of  the  external 
rectus  muscle  turned  downwards.  On  this  muscle  the  sixth  nerve  is  seen  dividing  into  branches.  9.  The 
inferior  rectus  muscle.  10.  The  optic  nerve.  11.  The  internal  carotid  artery  emerging  from  the  cavernous 
sinus.  12.  The  ophthalmic  artery.  13.  The  third  nerve.  14.  The  branch  of  the  third  nerve  to  the  inferior 
oblique  muscle.  Between  this  and  the  sixth  nerve  (7)  is  seen  the  branch  which  supplies  the  inferior  rectus; 
its  branch  to  the  ophthalmic  ganglion  is  seen  proceeding  from  the  upper  side  of  the  trunk  of  the  nerve,  at  the 
bottom  of  the  orbit.  15.  The  fourth  nerve.  16.  The  trunk  of  the  fifth  nerve.  17.  The  Gasserian  ganglion. 
18.  The  ophthalmic  nerve.  19.  The  superior  maxillary  nerve.  20.  The  inferior  maxillary  nerve.  21.  The 
frontal  nerve.  22.  Its  division  into  branches  to  supply  the  integument  of  the  forehead.  23.  The  lachrymal 
nerve.  24.  The  nasal  nerve;  the  small  nerve  seen  in  the  bifurcation  of  the  nasal  and  frontal  nerve  is  one 
of  the  branches  of  the  upper  division  of  the  third  nerve .  25 .  The  nasal  nerve  passing  over  the  internal  rectus 
muscle  to  the  anterior  ethmoidal  foramen.  26.  The  infra-trochlear  nerve.  27.  A  long  ciliary  branch  of  the 
nasal ;  another  long  ciliary  branch  is  seen  proceeding  from  the  lower  aspect  of  the  nerve.  28.  The  long  root 
of  the  ophthalmic  ganglion,  proceeding  from  the  nasal  nerve,  and  receiving  the  sympathetic  root  which  joins 
it  at  an  acute  angle.  29.  The  ophthalmic  ganglion,  giving  off  from  its  fore  part  the  short  ciliary  nerves.  30. 
The  globe  of  the  eye. 

however,  it  anastomoses  with  other  nerves ;  and  thus  sensory  fibres  are  intro- 
duced into  it  from  many  different  sources — anteriorly,  from  the  5th  pair,  and 
posteriorly,  from  the  cervical  nerves — which  cause  irritation  of  several  of  its 
branches  to  produce  pain.  The  number  and  situation  of  the  anastomoses  vary 
much  in  different  animals ;  so  that  it  is  impossible  to  make  any  very  compre- 
hensive statement  in  regard  to  them. — Experimental  researches  leave  no  doubt 
that  the  Portio  Dura  is  the  general  motor  nerve  of  the  face ;  ministering  to  the 
influence  of  Volition  and  of  Emotion,  and  also  being  the  channel  of  the  reflex 
movements  concerned  in  respiration  and  other  automatic  actions  of  the  muscles ; 
but  not  being  in  the  least  concerned  in  the  act  of  mastication. 

717.  The  functions  of  the  Glosso-Pharyngeal  nerve  have  been  heretofore 
alluded  td  in  part ;  but  there  still  remain  several  questions  to  be  discussed  in 
regard  to  them.  Reasons  have  been  given  for  the  belief  that  it  is  chiefly  an 
afferent  nerve — scarcely  having  any  direct  power  of  exciting  muscular  contrac- 


CEPHALIC   NERVES.  —  GLOSSO-PHARYNGEAL   NERVE.  687 

tion,  but  conveying  impressions  to  the  Medulla  Oblongata,  which  produce  reflex 
movements  of  the  motor  nerves  concerned  in  deglutition  (§  427).  This  view 
of  its  function  was  deduced  by  Dr.  J.  Reid  from  minute  anatomical  investiga- 
tion, and  from  a  large  number  of  experiments.  Some  experimenters  assert  that 

Fig.  185. 


The  distribution  of  the  Facial  nerve,  and  the  branches  of  the  Cervical  plexus. — 1.  The  facial  nerve,  escaping 
from  the  stylo-mastoid  foramen,  and  crossing  the  ramus  of  the  lower  jaw;  the  parotid  gland  has  been  removed 
in  order  to  see  the  nerve  more  distinctly.  2.  The  posterior  auricular  branch;  the  digastric  and  stylo-mastoid 
filaments  are  seen  near  the  origin  of  this  branch.  3.  Temporal  branches,  communicating  with  (4)  the  branches 
of  the  frontal  nerve.  5.  Facial  branches,  communicating  with  (6)  the  infra-orbital  nerve.  7.  Facial  branches, 
communicating  with  (8)  the  mental  nerve.  9.  Cervico-facial  branches,  communicating  with  (10)  the  super- 
ficialis  colli  nerve,  and  forming  a  plexus  (11)  over  the  submaxillary  gland.  The  distribution  of  the  branches 
of  the  facial  in  a  radiated  direction  over  the  side  of  the  face  constitutes  the  pes  anserinus.  12.  The  auricularis 
mognus  nerve,  one  of  the  ascending  branches  of  the  cervical  plexus.  13.  The  occipitalis  minor,  ascending  along 
the  posterior  border  of  the  sterno-mastoid  muscle.  14.  The  superficial  and  deep  descending  branches  of  the 
cervical  plexus.  15 .  The  spinal  accessory  nerve,  giving  off  a  branch  to  the  external  surface  of  the  trapezius 
muscle.  16.  The  occipitalis  major  nerve,  the  posterior  branch  of  the  second  cervical  nerve. 

they  have  succeeded  in  exciting  direct  muscular  actions  through  its  trunk ;  but 
these  actions  seem  to  be  limited  to  the  stylo-pharyngei  and  to  the  palato-glossi 
muscles.  Much  controversy  has  taken  place  on  the  question  whether  this  nerve 
is  to  be  regarded  as  ministering,  partly  or  exclusively,  to  the  sense  of  Taste ; 
and  many  high  authorities  have  ranged  themselves  on  each  side.  The  question 
involves  that  of  the  function  of  the  Lingual  branch  of  the  5th  pair ;  and  it  is 
partly  to  be  decided  by  the  anatomical  relations  of  the  two  nerves  respectively. 
The  Glosso-pharyngeal  is  principally  distributed  on  the  mucous  surface  of  the 
fauces,  and  on  the  back  of  the  tongue ;  but,  according  to  Valentin,  it  sends  a 
branch  forwards,  on  either  side,  somewhat  beneath  the  lateral  margin,  which 
supplies  the  edges  and  inferior  surface  of  the  tip  of  the  tongue,  and  inosculates 
with  the  Lingual  branch  of  the  5th.  On  the  other  hand,  the  upper  surface  of 
the  front  of  the  tongue  is  supplied  by  this  Lingual  branch.  The  experiments 
of  Dr.  Alcock,  whose  conclusions  are  borne  out  by  Dr.  J.  Reid,  decidedly  sup- 
port the  conclusion  that  the  gustative  sensibility  of  this  part  of  the  tongue  is 
chiefly  due  to  the  latter  nerve,  being  evidently  impaired  by  division  of  it.  On 
the  other  hand,  it  is  equally  certain  that  the  sense  of  taste  is  not  destroyed  by 


688  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

section  of  the  Lingual  nerve  on  each  side  \  and  it  seems  also  well  ascertained, 
that  it  is  impaired  by  section  of  the  Glosso-pharyngeal  nerve. — The  pathological 
evidence  bearing  upon  this  point  appears  somewhat  contradictory.  Numerous 
cases  have  been  recorded,1  in  which  both  common  and  gustative  sensation  were 
destroyed  in  the  parts  of  the  tongue  supplied  by  the  5th  pair,  when  that  nerve 
was  paralyzed ;  in  some  of  these,  the  loss  of  the  sense  of  taste  appeared  to  ex- 
tend itself  to  the  base  of  the  tongue,  but  then  there  was  evidence  that  the  Glosso- 
pharyngeal  was  involved  in  the  paralysis.  On  the  other  hand,  cases  of  paralysis 
of  the  5th  pair  are  related  by  Mr.  Noble  and  by  Vogt,2  in  which  common  sen- 
sation was  lost,  whilst  the  sense  of  taste  remained  in  the  same  parts ;  and  Mr. 
Noble  relates  another  case,3  in  which  there  was  loss  of  taste  without  impairment 
of  common  sensation.  The  cases  of  Mr.  Noble  and  Vogt  would  seem  to  indicate 
that  the  5th  pair  does  not  minister  to  the  sense  of  Taste ;  but,  as  Dr.  J.  Reid 
has  justly  observed,  we  have  no  evidence  that  all  the  filaments  of  the  5th  Pair 
sent  to  the  tongue  were  affected ;  and  there  is  believed  to  be  no  case  on  record, 
in  which  the  whole  of  the  5th  pair,  or  of  its  3d  branch,  was  found  to  be  dis- 
eased after  death,  and  in  which  during  life  the  sense  of  Taste  had  been  retained 
in  the  anterior  and  middle  parts  of  the  tongue.  Hence  these  cases  only  serve 
to  indicate  what  is  probable  on  other  grounds ;  viz.,  that  the  filaments  which 
convey  gustative  impressions  are  not  the  same  with  those  that  minister  to  com- 
mon sensation. — On  the  whole,  then,  it  seems  to  be  proved  by  anatomical  and 
experimental  evidence,  that  both  the  Glosso-pharyngeal  and  the  Fifth  pair  min- 
ister alike  to  the  tactile  and  to  the  gustative  sense ;  and  there  is  nothing  in  the 
pathological  facts  just  noticed  that  militates  against  this  conclusion.  There 
seems  good  reason  to  believe  the  Glosso-pharyngeal  to  be  exclusively  the  nerve, 
through  which  the  impressions  made  by  disagreeable  substances  taken  into  the 
mouth  are  propagated  to  the  Medulla  Oblongata,  so  as  to  produce  nausea  and  to 
excite  efforts  to  vomit. 

718.  The  functions  of  the  Pneumogastric  nerve  at  its  roots  have  been  made 
the  subject  of  particular  examination  by  various  experimenters ;  some  of  whom 
(for  instance,  Valentin,  Longet,  and  Morganti)  have  concluded  that  it  there 
possesses  no  motor  power,  but  is  entirely  a  sensory  or  rather  an  afferent  nerve. 
According  to  these,  if  the  roots  be  carefully  separated  from  those  of  the  Glosso- 
Pharyngeal,  and  (which  is  a  matter  of  some  difficulty)  from  those  of  the  Spinal 
Accessory  nerve,  and  be  then  irritated,  no  movements  of  the  organs  supplied  by 
its  trunk  can  be  observed :  whilst,  if  the  roots  be  irritated  when  in  connection 
with  the  nervous  centres,  muscular  contractions,  evidently  of  a  reflex  character, 
result  from  the  irritation ;  and  strong  evidences  of  their  sensibility  are  also 
given.  It  has  been  further  asserted  that,  when  the  roots  of  the  Spinal  Acces- 
sory nerve  are  irritated,  no  indications  of  sensation  are  given ;  but  that  the 
muscular  parts  supplied  by  the  Pneumogastric,  as  well  as  by  its  own  trunk,  are 
made  to  contract,  even  when  the  roots  are  separated  from  the  nervous  centres ; 
so  that  these  roots  must  be  regarded  as  the  channel  of  the  motor  influence,  trans- 
mitted to  them  from  the  Medulla  Oblongata.  Where  the  Pneumogastric  swells 
into  the  jugular  ganglion,  an  interchange  of  fibres  takes  place  between  it  and 
the  Spinal  Accessory ;  and  it  seems  clear  that  the  pharyngeal  branches,  which 
are  among  the  most  decidedly  motor  of  all  those  given  off  from  the  Pneumogas- 
tric, may  in  great  part  be  traced  backwards  into  the  Spinal  Accessory. — But,  on 
the  other  hand,  an  equally  numerous  and  trustworthy  set  of  experimenters 
(among  whom  may  be  mentioned  J.  Reid,  Mliller,  Volkmann,  Stilling,  Wagner, 

1  See  especially  the  cases  of  Romberg,  in  "  Mxiller's  Archiv.,"  1838,  heft  iii. ;  Todd 
and  Bowman,  in  "  Physiological  Anatomy,"  p.  386,  Am.  Ed.  ;  and  Dixon,  in  "  Mod.  Chir. 
Trans.,"  vol.  xxviii. 

2  "  Medical  Gazette,"  Oct.  25,  1834;  and  "Mailer's  Archiv.,"  1840,  p.  72. 

3  "  Medical  Gazette,"  Nov.  21,  1835. 


CEPHALIC   NERVES. — PNEUMOGASTRIC   NERVE. 
Fig.  186.  Fig.  187. 


689 


Origin  and  distribution  of  the  Eighth  Pair  of  nerves. 
1, 3, 4.  The  Medulla  Oblongata.  1.  The  Corpus  Pyra- 
midale  of  one  side.  3.  The  Corpus  Olivare.  4.  The 
Corpus  Restiforme.  2.  The  Pons  Varolii.  5.  The  Fa- 
cial nerve.  6.  The  origin  of  the  Glosso-pharyngeal 
nerve.  7.  The  ganglion  of  Andersch.  8.  The  trunk 
of  the  nerve.  9.  The  Spinal  Accessory  nerve.  10. 
The  ganglion  of  the  Pneumogastric  nerve.  11.  Its 
plexiforrn  ganglion.  12.  Its  trunk.  13.  Its  pharyn- 
geal  branch  forming  the  pharyngeal  plexus  (14),  as- 
sisted by  a  branch  from  the  glosso-pharyngeal  (8)  and 
one  from  the  superior  laryngeal  nerve  (15).  16.  Car- 
diac branches.  17 .  Recurrent  laryngeal  branch.  18. 
Anterior  pulmonary  branches.  19.  Posterior  pulmon- 
ary branches.  20.  (Esophageal  plexus.  21.  Gastric 
branches.  22.  Origin  of  the  Spinal  Accessory  nerve. 
23.  Its  branches  distributed  to  the  sterno-mastoid 
muscle.  24.  Its  branches  to  the  trapezius  muscle. 

44 


A  view  of  the  distribution  of  the  Glosso-Pharyngeal 
Pneumogastric  and  Spinal  Accessory  Nerves,  or  the 
Eighth  pair:  1,  the  inferior  maxillary  nerve;  2,  the 
gustatory  nerve;  3,  the  chorda  tympani;  4,  the  auri- 
cular nerve;  5,  its  communication  with  the  portio 
dura ;  6,  the  facial  nerve  coming  out  of  the  stylo- 
mastoid  foramen ;  7,  the  glosso-pharyngeal  nerve ;  8, 
branches  to  the  stylo-pharyngeus  muscle ;  9,  the  pha- 
ryngeal branch  of  the  pneumogastric  nerve  descend- 
ing to  form  the  pharyngeal  plexus;  10,  branches  of 
the  glosso-pharyngeal  to  the  pharyngeal  plexus ;  11, 
the  pneumogastric  nerve  ;  12,  the  pharyngeal  plexus ; 
13,  the  superior  laryngeal  branch ;  14,  branches  to 
the  pharyngeal  plexus ;  15, 15,  communication  of  the 
superior  and  inferior  laryngeal  nerves;  16,  cardiac 
branches ;  17,  cardiac  branches  from  the  right  pneu- 
mogastric nerve;  18,  the  left  cardiac  ganglion  and 
plexus  ;  19,  the  recurrent  or  inferior  laryngeal  nerve ; 
20,  branches  sent  from  the  curve  of  the  recurrent 
nerve  to  the  pulmonary  plexus ;  21.  the  anterior  pul- 
monary plexus;  22,  22,  the  oesophageal  plexus. 


690  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

and  Bernard)  are  opposed  to  this  opinion ;  maintaining  that  the  Pneumogastric 
has  motor  roots  of  its  own ;  and  affirming  that  irritation  of  the  roots  of  the  Spi- 
nal Accessory  produces  little  or  no  effect  on  the  muscles  supplied  by  the  trunk 
of  the  Par  Vagum. — The  fact  appears  to  be  that  the  roots  of  these  two  nerves 
are  so  commingled,  that  it  is  difficult  to  say  what  belongs  exclusively  to  each. 
Some  of  the  fibres  usually  considered  to  belong  to  the  Spinal  Accessory  are 
occasionally  seen  to  connect  themselves  with  the  roots  of  the  Pneumogastric, 
even  before  the  ganglion  is  found  upon  it.  And  it  seems  most  probable  that, 
while  the  roots  of  the  Spinal  Accessory  are  entirely  motor,  those  of  the  Pneu- 
mogastric are  chiefly  afferent ;  that  they  inosculate  with  each  other,  in  a  degree 
which  may  vary  in  different  species,  and  even  in  different  individuals ;  and  that 
the  Pneumogastric  may  thus  derive  additional  motor  fibres  from  the  Spinal  Acces- 
sory, whilst  it  supplies  that  nerve  with  afferent  fibres.  Further,  from  the  re- 
searches of  M.  Cl.  Bernard,  to  be  presently  noticed  (§  719),  it  appears  probable 
that  the  motor  fibres  properly  belonging  to  the  Pneumogastric  are  adequate  to 
the  regulation  of  those  movements  of  the  larynx  and  other  portions  of  the  air- 
passages,  which  are  concerned  in  the  passive  act  of  Respiration. — In  regard  to 
its  trunk ,  there  can  be  no  doubt  that  the  Pneumogastric  is  to  be  considered  as 
a  nerve  of  double  endowments ;  although  it  is  certain  that  these  endowments 
are  very  differently  distributed  amongst  its  branches.  That  the  nerve  is  capable 
of  conveying  those  impressions,  which  become  sensations  when  communicated  to 
the  sensorium,  is  experimentally  proved  by  the  fact  that,  when  its  trunk  is 
pinched,  the  animal  gives  signs  of  acute  pain  :  but  it  is  also  evident  from  the 
painful  consciousness  we  occasionally  have  of  an  abnormal  condition  of  the 
organs  which  it  supplies.  Thus,  the  suspension  of  the  respiratory  movements 
gives  rise  to  a  feeling  of  the  greatest  uneasiness,  which  must  be  excited  by  im- 
pressions conveyed  through  this  nerve  from  the  lungs  ;  and  an  inflamed  state  of 
the  walls  of  the  air-passages  causes  the  contact  of  cold  and  dry  air  to  produce 
distressing  pain  and  irritation.  Yet  of  the  ordinary  impressions  conveyed  from 
these  organs,  which  are  concerned  in  producing  the  respiratory  movements,  and 
in  regulating  the  actions  of  the  glottis,  we  are  not  conscious.  The  same  may 
be  said  of  the  portion  of  the  nerve  distributed  upon  the  alimentary  tube.  The 
pharyngeal  branches  are  almost  exclusively  motor,  the  afferent  function  being 
performed  by  the  Grlosso-pharyngeal;  whilst  the  cesophageal  and  gastric  are  both 
afferent  and  motor,  conveying  impressions  which  excite  reflex  movements  in  the 
muscles  of  those  parts,  but  which  do  not  become  sensations  except  under  extra- 
ordinary circumstances. — The  participation  of  this  nerve  in  the  operations  of 
Deglutition,  Digestion,  Circulation,  and  Respiration,  and  the  effects  of  injury  to 
its  trunk  or  branches,  have  already  been  considered  in  the  account  of  those 
functions. 

719.  In  regard  to  the  functions  of  the  Spinal  Accessory  nerve,  also,  there 
has  been  great  difference  of  opinion;  the  peculiarity  of  its  origin  and  course 
having  led  to  the  belief  that  some  very  especial  purpose  is  answered  by 
it.  The  roots  of  this  nerve  arise  from  the  side  of  the  Spinal  Cord  as  low  down 
as  the  5th  or  6th  cervical  nerve  j  and  the  trunk  formed  by  them  ascends  into 
the  cranium  between  the  anterior  and  posterior  roots  of  the  spinal  nerves. 
From  the  recent  researches  of  Mr.  J.  L.  Clarke,1  it  appears  that  these  roots 
may  be  traced  into  a  special  tract  of  vesicular  matter,  which  descends  as  far  as 
the  lumbar  enlargement.  The  predominance  of  motor  fibres  in  its  roots,  its 
inosculation  with  the  Pneumogastric,  and  its  probable  reception  of  sensory 
fibres  from  the  latter  whilst  imparting  to  it  motor  filaments,  have  been  already 
referred  to  (§  718).  As  its  trunk  passes  through  the  foramen  lacerum,  it 
divides  into  two  branches;  of  which  the  internal,  after  giving  off  some  filaments 

1   "  Philosophical  Transactions,"  1851,  p.  C13. 


CEPHALIC   NERVES.  —  HYPOGLOSSAL   NERVE.  691 

that  assist  in  forming  the  pharyngeal  branch  of  the  Pneumogastric,  becomes 
incorporated  with  the  trunk  of  that  nerve;  whilst  the  external  proceeds  out- 
wards, and  is  finally  distributed  to  the  sterno-cleido-mastoideus  and  trapezius 
muscles,  some  of  its  filaments  inosculating  with  those  of  the  cervical  plexus. 
When  the  external  branch  is  irritated,  before  it  perforates  the  sterno-mastoid 
muscle,  vigorous  convulsive  movements  of  that  muscle  and  of  the  trapezius  are 
produced ;  and  the  animal  does  not  give  any  signs  of  pain,  unless  the  nerve  be 
firmly  compressed  between  the  forceps,  or  be  included  in  a  tight  ligature. 
Hence  it  may  be  inferred  that  the  functions  of  this  nerve  are  chiefly  motor,  and 
that  its  sensory  filaments  are  few  in  number.  Further,  when  the  nerve  has 
been  cut  across,  or  firmly  tied,  irritation  of  the  lower  end  is  attended  by  the 
same  convulsive  movements  of  the  muscles;  whilst  irritation  of  the  upper  end, 
in  connection  with  the  spinal  cord,  is  unattended  with  any  muscular  movement. 
Hence  it  is  clear  that  the  motions  occasioned  by  irritating  it  are  of  a  direct,  not 
of  a  reflex  character.  The  same  muscular  movements  are  observed  on  irritat- 
ing the  nerve  in  the  recently-killed  animal,  as  during  life. — According  to  Sir 
C.  Bell,  the  Spinal  Accessory  is  a  purely  Respiratory  nerve,  whose  office  it  is  to 
excite  the  involuntary  or  automatic  movements  of  the  muscles  it  supplies,  which 
share  in  the  act  of  respiration;  and  he  states  that  the  division  of  it  para- 
lyzes, as  muscles  of  respiration,  the  muscles  to  which  it  is  distributed;  though 
they  still  perform  the  voluntary  movements,  through  the  medium  of  the  spinal 
nerves.  Both  Valentin  and  Dr.  J.  Reid,  however,  positively  deny  that  this  is 
the  case ;  and  Dr.  Reid's  method  of  experimenting  was  well  adapted  to  test  the 
truth  of  the  assertion.1  The  functions  of  this  nerve  have  been  made  the  sub- 
ject of  special  examination  by  M.  Cl.  Bernard,3  who  has  arrived  at  the  conclu- 
sion that  the  Spinal  Accessory  is  a  purely  motor  nerve,  whose  action  is  not 
essential  to  the  ordinary  movements  of  respiration,  these  being  provided  for  by 
the  Pneumogastric  and  ordinary  Spinal  nerves;  but  that  its  special  function  is 
to  bring  the  respiratory  movements  into  accordance  with  the  requirements  of 
Animal  life,  adapting  the  actions  of  the  muscles  of  the  larynx  and  thorax  to 
the  production  of  voice,  or  to  general  muscular  effort.  The  internal  branch, 
which  is  especially  distributed,  with  the  fibres  of  the  Pneumogastric,  to  the 
pharynx  and  larynx,  is  peculiarly  subservient  to  the  former  of  these  purposes; 
and  the  external  to  the  latter.  This  conclusion  is  sufficiently  in  accordance  with 
the  results  obtained  by  other  experimenters,  to  be  received  as  a  probable  expla- 
nation of  the  facts  which  have  been  observed  by  them. 

720.  The  Hypoglossal  nerve,  or  Motor  Linguae,  is  the  only  one  which,  in  the 
regular  order,  now  remains  to  be  considered.  That  the  distribution  of  this 
nerve  is  restricted  to  the  muscles  of  the  tongue  is  a  point  very  easily  esta- 
blished by  anatomical  research ;  and  accordingly,  we  find  that  long  before  the 
time  of  Sir  C.  Bell,  Willis  had  spoken  of  it  as  the  nerve1  of  the  motions  of 
articulation,  whilst  to  the  Lingual  branch  of  the  5th  pair  he  attributed  the 
power  of  exercising  the  sense  of  taste ;  and  he  distinctly  stated  that  the  reason 
of  this  organ  being  supplied  with  two  nerves  is  its  double  function.  The 
inference  that  it  is  chiefly,  if  not  entirely,  a  motor  nerve,  which  has  been 
founded  upon  its  anatomical  distribution,  is  supported  also  by  the  nature  of  its 
origin,  which  is  usually  from  a  single  root,  corresponding  to  the  anterior  root 

1  See  his  "Physiol.,  Pathol.,  and  Anat.  Researches,"  p.  151 ;  and  "Edinb.  Med.  and 
Surg.  Journ.,"  Jan.,  1838. 

2  " Recherches  Experimentales  sur  les  Fonctions  du  Nerf  Spinal,"  in  "Archives  de 
Medecine,"  1844.     This  memoir,  having  gained  the  prize  given  by  the  Academic  des 
Sciences  for  experimental  physiology  in  1845,  has  been  printed  in  the  "  Recueil  des  Savants 
Strangers,"  torn,  xi.,  1851 ;  and  the  author  states  that  since  the  first  publication  of  his 
researches,  he  has  confirmed  his  original  conclusions  by  the  repetition  and  variation  of  his 
experiments. 


692  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

of  the  Spinal  nerves.  Experiment  shows  that,  when  the  trunk  of  the  nerve 
is  stretched,  pinched,  or  galvanized,  violent  motions  of  the  whole  tongue,  even 
to  its  tip,  are  occasioned  ;  and  also,  that  similar  movements  take  place  after  divi- 
sion of  the  nerve,  when  the  cut  end  most  distant  from  the  brain  is  irritated. 
In  regard  to  the  degree  in  which  this  nerve  possesses  sensory  properties,  there 

Fig.  188. 


The  course  and  distribution  of  tlie  Hypoglossal  or  Ninth  pair  of  nerves ;  the  deep-seated  nerves  of  the 
neck  are  also  seen:  1,  the  hypoglossal  nerve;  2,  branches  communicating  with  the  gustatory  nerve;  3,  a 
branch  to  the  origin  of  the  hyoid  muscles  ;  4,  the  descendens  noni  nerve ;  5,  the  loop  formed  with  the  branch 
from  the  cervical  nerves ;  6,  muscular  branches  to  the  depressor  muscles  of  the  larynx ;  7,  a  filament  from 
the  second  cervical  nerve,  and  8,  a  filament  from  the  third  cervical,  uniting  to  form  the  communicating 
branch  with  the  loop  from  the  descendens  noni;  9,  the  auricular  nerve;  10,  the  inferior  dental  nerve;  11,  its 
mylo-hyoidean  branch ;  12,  the  gustatory  nerve  ;  13,  the  chorda  tympani  passing  to  the  gustatory  nerve ; 
14,  the  chorda  tympani  leaving  the  gustatory  nerve  to  join  the  submaxillary  ganglion ;  15,  the  submaxillary 
ganglion ;  16,  filaments  of  communication  with  the  lingual  nerve ;  17,  the  glosso-pharyngeal  nerve ;  18,  the 
pneumogastric  or  par  vagum  nerve ;  19,  the  three  upper  cervical  nerves  ;  20,  the  four  inferior  cervical  nerves; 
21,  the  first  dorsal  nerve ;  22,  23,  the  brachial  plexus;  24,  25,  the  phrenic  nerve;  26,  the  carotid  artery;  27, 
the  internal  jugular  vein. 

is  some  difference  of  opinion  amongst  physiologists,  founded,  as  it  would  seem, 
on  a  variation  in  this  respect  between  different  animals.  Indications  of  pain 
are  usually  given,  when  the  trunk  is  irritated  after  its  exit  from  the  cranium  ]  but 
these  may  proceed  from  its  free  anastomosis  with  the  cervical  nerves,  which  not 
improbably  impart  sensory  fibres  to  it.  But  in  some  Mammalia,  the  hypoglossal 
nerve  has  been  found  to  possess  a  small  posterior  root  with  a  ganglion ;  this  is  the 
case  in  the  Ox,  and  also  in  the  Rabbit ;  and  in  the  latter  animal,  Valentin 
states  that  the  two  trunks  pass  out  from  the  cranium  through  separate  orifices, 
and  that,  after  their  exit,  one  may  be  shown  to  be  sensory,  and  the  other  to  be 
motor.  Hence,  this  nerve,  which  is  the  lowest  of  those  that  originate  in  the 
cephalic  prolongation  of  the  spinal  cord  generally  known  as  the  medulla  oblongata, 
approaches  very  closely  in  some  animals  to  the  regular  type  of  the  spinal  nerves  ; 
and  though  in  Man  it  still  manifests  an  irregularity  in  having  only  a  single 
root,  yet  this  irregularity  is  often  shared  by  the  first  cervical  nerve,  which  also 
has  sometimes  an  anterior  root  only.  The  Hypoglossal  nerve  is  distributed  not 
merely  to  the  tongue,  but  to  the  muscles  of  the  neck,  which  are  concerned  in 
the  movements  of  the  larynx ;  and  the  purpose  of  this  distribution  is  probably 


HYPOGLOSSAL  NERVE.  —  CEPHALIC  NERVES  IN  GENERAL.   693 

to  associate  them  in  those  actions  which  are  necessary  for  articulate  speech. 
Though  all  the  motions  of  the  tongue  are  performed  through  the  medium  of 
this  nerve,  yet  it  would  appear,  from  pathological  phenomena,  to  have  at  least 
two  distinct  connections  with  the  nervous  centres ;  for  in  many  cases  of  paraly- 
sis, the  masticatory  movements  of  the  tongue  are  but  little  affected,  when  the 
power  of  articulation  is  much  injured  or  totally  destroyed;  and  the  converse 
may  be  occasionally  noticed.  When  this  nerve  is  paralyzed  on  one  side,  in 
hemiplegia,  it  will  be  generally  observed  that  the  tongue,  when  the  patient  is 
directed  to  put  it  out,  is  projected  towards  the  palsied  side  of  the  face :  this  is 
due  to  the  want  of  action  of  the  lingual  muscles  of  that  side,  which  do  not  aid 
in  pushing  forward  the  tip ;  the  point  is  consequently  directed  only  by  the 
muscles  of  the  other  side,  which  will  not  act  in  a  straight  direction,  when  unan- 
tagonized  by  their  fellows.  It  is  a  curious  fact,  however,  that  the  Hypoglossal 
nerve  seems  not  to  be  always  palsied  on  the  same  side  with  the  Facial,  but 
sometimes  on  the  other.  This  has  been  suggested  to  be  due  to  the  origination 
of  the  roots  of  this  nerve  from  near  the  point  at  which  the  pyramids  of  the 
medulla  oblongata  decussate,  so  that  some  of  its  fibres  come  off,  like  those  of 
the  spinal  nerves,  without  crossing,  whilst  others  are  trknsmitted  to  the  oppo- 
site side,  like  those  of  the  higher  cephalic  nerves ;  and  the  cause  of  paralysis 
may  affect  one  or  other  of  these  sets  of  roots  more  particularly.  Whatever 
may  be  the  validity  of  this  explanation,  the  circumstance  is  an  interesting  one, 
and  well  worthy  of  attention.1 

721.  The  general  character  and  arrangement  of  the  Cephalic  nerves,  as  dis- 
tinguished from  the  ordinary  Spinal,  constitute  a  study  of  much  interest,  when 
considered  in  relation  to   Comparative  Anatomy,  and  to  Embryology.     It  ap- 
pears, from  what  has  been  already  stated,  that  the  Pneumogastric,  Spinal  Ac- 
cessory, Grlosso-pharyngeal,  and  Hypoglossal  nerves,  may  be  considered  nearly 
in  the  light  of  ordinary  Spinal  nerves.     They  all  take  their  origin  exclusively 
in  the  Medulla  Oblongata ;  and  the  want  of  correspondence  in  position,  between 
their  roots  and  those  of  the   Spinal  nerves,  is  readily  accounted  for  by  the 
alteration  in  the  direction  of  the  columns  of  the  Spinal  cord,  which  not  only 
decussate  laterally,  but,  as  it  were,  antero-posteriorly  (§  711).     The  Hypoglos- 
sal, as  just  stated,  not  unfrequently  possesses  a  sensory  in  addition  to  its  motor 
root.     The  Grlosso-pharyngeal,   which  is  principally  an  afferent  nerve,  has  a 
small  motor  root ;  but  most  of  the  motor  fibres  which  answer  to  it  are  to  be 
found  in  the  Pneumogastric.     That  the  Pneumogastric  and   Spinal  Accessory 
together  represent  a  spinal  nerve,  may  be  regarded  as  probable  from  what  has 
been  already  said  of  their  relations. 

722.  Leaving  these  nerves  out  of  the  question,  therefore,  we  proceed  to  the, 
rest.     Comparative  anatomy,  and  the  study  of  Embryonic  development,  alike 
show  that  the  Spinal  Cord  and  Medulla  Oblongata  constitute  the  most  essential 
part  of  the  nervous  system  in  Vertebrata ;  and  that  the  Cerebral  Hemispheres  are 
superadded,  as  it  were,  to  this.     At  an  early  period  of  development,  the  Ence- 
phalon  consists  chiefly  of  four  vesicles,  which  correspond  with  the  ganglionic 
enlargements  of  the  nervous  cord  of  the  Articulata,  and  mark  four  divisions  of 
the  Cerebro-Spinjd  axis ;  and,  in  accordance  with  this  view,  the  Osteologist  is 
able  to  trace,  in  the  bones  of  the  cranium,  the  same  elements  which  would  form 
four  vertebrae,  in  a  much  expanded  and  altered  condition.3     However  improba- 

1  It  may  be  questioned,  however,  whether  the  Hypoglossal  is  really  paralyzed  on  the 
opposite  side  from  the  Facial  in  such  cases.     An  instance  has  been  communicated  to  the 
Author  by  Dr.  W.  Budd,  in  which  the  hypoglossal  nerve  was  completely  divided  on  one 
side  ;  and  yet  the  tip  of  the  tongue,  when  the  patient  was  desired  to  put  it  out,  was  some- 
times directed  from  and  sometimes  towards  the  palsied  side;  showing  that  the  muscles  of 
either  half  are  sufficient  to  give  any  required  direction  to  the  whole. 

2  See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  Am.  Ed.,  g  320,  t ;  and  Prof.  Owen's  "Arche- 
type Skeleton." 


694 


OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 


ble  such  an  idea  might  seem,  when  the  cranium  of  the  higher  Vertebrata  alone 
is  examined,  it  at  once  reconciles  itself  to  our  reason,  when  we  direct  our  atten- 
tion to  that  of  Reptiles  and  Fishes ;  in  which  classes  the  size  of  the  Cerebral 

[Fig.  188*. 


The  drawing  exhibits  the  cerebral  connection  of  all  the  cerebral  nerves  except  the  1st.  It  is  from  a 
sketch  taken  from  two  dissections  of  this  part.  D.  Posterior  optic  tubercle.  The  generative  bodies  of  the 
thalamus  are  just  above  it.  E.  Cerebellum.  H.  Spinal  cord.  i.  Tuber  cinereum.  K.  Optic  thalamus  divided 
perpendicularly,  w.  Corpus  restifonne.  x.  Pons  Varolii.  6  b.  Optic  nerves :  this  nerve  is  traced  on  the  left 
side  back  beneath  the  optic  thalamus  and  round  the  crus  cerebri.  It  divides  into  four  roots ;  the  first  (g  g) 
plunges  into  the  substance  of  the  thalamus,  the  next  runs  over  the  external  geniculate  body  and  surface  of 
the  thalamus,  the  third  goes  to  the  anterior  optic  tubercle,  the  fourth  runs  to  D,  the  testis  or  posterior  optic 
tubercle,  c.  Third  pair  common  oculo-muscular,  arising  by  two  roots  like  the  spinal  roots  of  the  spinal 
nerves,  the  upper  from  the  gray  neurine  of  the  locus  niger,  the  lower  from  the  continuation  of  the  pyra- 
midal columns  in  the  crus  cerebri  and  Pons  Varolii,  p  t.  d.  Fourth  pair,  apparently  arising  from  the  inter- 
Cerebral  commissure  (ic),  but  really  plunging  down  to  the  olivary  tract  (o  t)  as  it  ascends  to  the  optic  tuber- 
cles, e  m.  Motor  or  non-ganglionic  root  of  the  fifth  pair,  arising  from  the  posterior  edge  of  the  olivary  tract. 
e.  Sensory  root  of  the  fifth  pair  running  down  between  the  olivary  tract  and  restiform  body  to  the  sensory 
tract.  /.  Sixth  pair,  or  abducens,  arising  from  the  pyramidal  tract,  g.  Seventh  pair,  facial  nerve,  or  portio 
dura,  arising  by  an  anterior  portion  from  the  olivary  tract  and  by  a  posterior  portion  from  the  cerebellic 
fibres  of  the  anterior  columns  as  they  ascend  on  the  corpus  restiforme,  w.  h.  Eighth  pair,  portio  mollis,  or 
auditory  nerve,  with  its  two  roots  embracing  the  restiform  body.  i.  Ninth  pair,  or  glosso-pharyngeal ;  and  j. 
Tenth  pair,  or  par  vagum,  plunging  into  the  restiform  ganglion.  J  J.  Fibres  of  the  optic  nerve  plunging 
into  the  thalamus;  immediately  below  these  letters  is  the  corpus  geniculatum  Bxternum.  k.  Eleventh 
pair,  or  lingual  nerve;  the  olivary  body  has  been  nearly  sliced  off  and  turned  out  of  its  natural  position; 
some  of  the  filaments  of  the  lingual  nerve  are  traced  into  the  deeper  portion  of  the  ganglion,  which  is  left 
in  its  situation ;  others  which  are  the  highest  are  evidently  connected  with  the  pyramidal  tract.1— ED.] 

or  hemispheric  ganglia  is  very  small,  in  comparison  with  that  of  the  ganglia  of 
Special  Sensation ;  and  in  which  the  latter  evidently  form  but  a  continuation  of 
the  Spinal  Cord,  modified  in  its  function :  so  that,  when  we  trace  upward  the 
cavity  of  the  spinal  column  into  that  of  the  cranium,  we  encounter  no  material 
change,  either  in  its  size  or  direction.  The  four  pairs  of  nerves  of  special  sen- 

1  ["Solly  on  the  Brain,"  Am.  Ed.] 


FUNCTIONS   OP   THE    SPINAL   AXIS.  695 

sation — Auditory,  Gustatory,  Optic,  and  Olfactory — make  their  way  out  through 
these  three  cranial  vertebrae  respectively.  At  a  later  period  of  development,  other 
nerves  are  interposed  between  these  ;  which,  being  inter  vertebral,  are  evidently 
more  analogous  to  the  Spinal  nerves,  both  in  situation  and  function.  A  separa- 
tion of  the  primitive  fibres  of  these  takes  place,  however,  during  the  progress  of 
development,  so  that  their  distribution  appears  irregular.  Thus  the  greater  part 
of  the  sensory  fibres  are  contained  in  the  large  division  of  the  Trigeminus : 
whilst  of  the  motor  fibres,  the  anterior  ones  chiefly  pass  forwards  as  the  Oculo- 
motor and  Patheticus ;  and  of  the  posterior,  some  form  the  small  division  of 
the  Trigeminus,  and  others  unite  with  the  first  pair  from  the  Medulla  Oblongata 
to  form  the  Facial.  This  last  fact  explains  the  close  union,  which  is  found  in 
Fishes  and  some  Amphibia,  between  that  nerve  and  those  proceeding  more 
directly  from  the  Medulla  Oblongata.  According  to  Valentin,  the  Grlosso- 
pharyngeal  is  the  sensory  portion  of  the  first  pair  from  the  Medulla  Oblongata, 
of  which  the  motor  part  is  chiefly  comprehended  in  the  Facial  nerve.  Although 
we  are  accustomed  to  consider  the  Fifth  pair  as  par  eminence  the  Spinal  nerve, 
of  the  head,  the  foregoing  statements,  founded  upon  the  history  of  develop- 
ment,1 show  that  the  nerves  of  the  Orbit  really  belong  to  its  motor  portion  ; 
they  may  consequently  be  regarded  as  altogether  forming  the  first  of  the  inter- 
vertebral  nerves  of  the  cranium.  The  Facial  and  Grlosso-pharyngeal  appear  to 
constitute  the  second  ;  whilst  the  Par  Vaguin  and  Spinal  Accessory,  forming 
the  third  pair,  intervene  between  this  and  the  true  Spinal,  of  which  the  Hypo- 
glossal  may  be  considered  as  the  first. 

723.  Functions  of  the  Spinal  Axis. — Whatever  view  we  may  take  of  the 
structure  of  the  Spinal  Cord,  no  doubt  can  be  fairly  entertained  that  it  must  be 
physiologically  treated  on  the  one  hand  as  a  true  centre  (or  rather  as  an  aggre- 
gation of  separate  centres)  of  nervous  power,  and  on  the  other  as  a  medium  of 
conduction  between  the  Encephalic  centres  and  the  roots  of  the  Spinal  nerves. 
And  although  its  attributes  as  an  independent  centre  become  most  obvious  when 
it  is  separated  from  the  rest,  yet  there  can  be  no  reasonable  doubt  that  it  is 
always  acting  as  such,  even  when  every  part  of  the  Nervous  System  is  in  a  state 
of  complete  vigor.  It  may,  in  fact,  be  said  to  supply,  by  its  "  reflex  power," 
the  conditions  requisite  for  the  maintenance  of  the  various  Organic  processes  ; 
and,  as  Dr.  M.  Hall  has  pointed  out,  it  especially  governs  the  various  orifices  of 
ingress  and  egress.  Thus  the  act  of  Deglutition  is  entirely  dependent  upon 
the  Spinal  Axis  and  the  nerves  proceeding  from  it ;  the  Will  being  in  no  other 
way  concerned  in  it  than  by  originating  the  necessary  stimulus ;  and  even  sen- 
sation not  being  a  necessary  link  in  the  chain  of  excito-motor  action  (§§  426 — 
428).  The  action  of  the  cardiac  sphincter,  again — and  probably  that  of  the 
pyloric  sphincter  also — is  dependent  upon  its  nervous  connection  with  the 
Spinal  Axis ;  and  is  entirely  regulated  without  sensorial  excitement  (§  428). 
And  there  is  much  reason  to  believe  that  certain  of  the  movements  of  the 
Stomach  itself  are  in  like  manner  dependent  upon  its  connection  with  the  Me- 
dulla Oblongata  (§  480)  ]  although  it  unquestionably  possesses  an  independent 
motor  activity  of  its  own.  The  movements  of  the  Intestinal  tube  are  undoubt- 
edly influenced  by  the  Spinal  Cord,  although  essentially  independent  of  it 
(§§  432,  433) ;  but  the  sphincter  which  surrounds  its  orifice  of  egress  is  un- 
doubtedly placed  under  its  guardianship,  although  partly  subjected  (in  Man)  to 
the  control  of  the  Will.  The  same  may  be  said  of  the  expulsor  muscles  con- 
cerned in  the  act  of  Defecation ;  and  of  the  expulsors  and  sphincter  which 
effect  and  control  the  act  of  Urination  (§  434). — Looking,  again,  at  the  move- 
ments which  are  subservient  to  the  Respiratory  process,  we  find  that  all  those 

1  See  Prof.  Valentin  "De  Functionibus  Nervorum  Cerebralium  et  Nervi  Sympathetic!," 
Berrise,  1839  ;  lib.  iii.  cap.  i. 


696  OF   THE   FUNCTIONS   OF   THE    NERVOUS    SYSTEM. 

which  are  essential  to  its  regular  maintenance  are  performed  through  the  inter- 
mediation of  the  Spinal  Axis  alone ;  that  the  Will  has  only  such  a  limited 
power  over  them  as  to  bring  them  into  harmony  with  its  other  requirements,  as 
in  the  acts  of  vocalization  and  in  extraordinary  muscular  exertions  ;  and  that  the 
stimulus  by  which  they  are  commonly  maintained  does  not  even  affect  the  con- 
sciousness, the  "besoin  de  respirer"  only  becoming  sensible  when  the  respiratory 
process  is  being  imperfectly  performed  (§§  548 — 551).  Not  only  are  the  ordi- 
nary respiratory  movements  performed  through  this  channel,  but  the  aperture 
of  the  Glottis  is  regulated  by  it  in  everything  that  concerns  the  respiration ; 
and  either  by  its  spasmodic  closure  against  the  entrance  of  unfit  substances,  or 
by  the  expulsor  effort  of  coughing,  which  is  excited  by  them  when  they  do  find 
their  way  into  the  air-passages,  these  passages  are  kept  free  from  solid,  liquid, 
or  gaseous  particles,  whose  presence  in  them  would  be  injurious. — In  the  expul- 
sion of  the  Generative  products,  also,  the  reflex  power  of  the  Spinal  Cord  takes 
an  important  share.  The  muscular  contractions  which  produce  the  Emissio 
Seminis  are  excito-motor  in  their  nature;  being  independent  of  the  Will,  and 
not  capable  of  restraint  by  it  when  once  fully  excited  ;  and  being  (like  those  of 
Deglutition)  excitable  in  no  other  way  than  by  a  particular  local  irritation.  It 
has  been  shown  by  experiment,  and  also  by  pathological  observation,  that  the 
separation  of  the  lower  portion  of  the  Spinal  Cord  from  the  upper  does  not  pre- 
vent these  movements  from  being  excited,  although  the  act  is  then  unaccom- 
panied with  sensation,  which  proves  that  sensation  is  not  essential  to  its  perform- 
ance ;  on  the  other  hand,  the  power  of  emission  is  annihilated  by  destruction  of 
the  lower  portion  of  the  Spinal  Cord,  or  by  section  of  the  nerves  which  supply 
the  genital  organs.  The  act  of  Parturition,  however,  seems  to  be  less  depend- 
ent upon  the  Spinal  Cord ;  for,  as  will  be  shown  hereafter  (CHAP,  xix.),  the 
contractions  of  the  Uterus,  which  are  alone  sufficient  to  expel  the  foetus  when  there 
is  no  considerable  resistance,  are  not  to  be  regarded  as  reflex;  and  it  is  only  in 
the  co-operation  of  those  associated  muscles  which  come  into  play  in  the  second 
stage  of  labor,  when  the  head  is  passing  through  the  os  uteri  and  is  engaged  in 
the  pelvic  cavity,  that  the  assistance  of  the  Spinal  cord  and  its  nerves  is  called 
in.  These  movements,  like  those  of  Defecation,  may  be  to  a  certain  extent 
promoted  or  restrained  by  voluntary  effort ;  but  when  the  exciting  influence 
(the  pressure  of  the  head  against  the  parietes  of  the  vaginal  canal)  has  once 
been  fully  brought  into  operation  by  the  uterine  contractions,  the  Will  has  little 
power  over  them,  either  in  one  way  or  the  other.  The  antagonizing  influence  of 
the  sphincter  vaginae  seems,  like  that  of  the  sphincter  ani,  to  be  dependent 
upon  the  Spinal  Cord ;  and  thus  it  happens  that  when  its  tension  and  that  of 
other  muscular  parts  have  been  destroyed  by  death,  whilst  the  uterus  still  retains 
its  contractility,  the  power  of  the  latter  has  sufficed  for  the  completion  of  the 
parturient  process,  the  child  being  expelled  after  the  respiratory  movements 
have  ceased. 

724.  The  Spinal  Cord  is  not  merely  the  instrument  whereby  the  movements 
essential  to  the  maintenance  of  the  Organic  functions  are  sustained;  it  is  also 
subservient  to  other  muscular  actions  whose  character  is  essentially  protective. 
Thus  it  was  ascertained  by  Dr.  M.  Hall1  that,  if  the  functions  of  the  Brain  be 
suspended  or  destroyed,  without  injury  to  the  Spinal  Cord  and  its  nerves,  the 
Orbicularis  muscle  will  contract,  so  as  to  occasion  the  closure  of  the  eyelids, 
upon  their  tarsal  margin  being  touched  with  a  feather.  This  fact  is  interesting 
in  several  points  of  view.  In  the  first  place,  it  is  a  characteristic  example  of 
pure  reflex  action,  occurring  under  circumstances  in  which  volition  cannot  be 
imagined  to  guide  it,  and  in  which  there  is  no  valid  reason  to  believe  that  sen- 
sation directs  it.  Further,  it  explains  the  almost  irresistible  nature  of  the 

1  "Memoirs  on  the  Nervous  System,"  1837,  p.  61. 


FUNCTIONS    OF   THE    SPINAL   AXIS.  697 

tendency  to  winking,  which  is  performed  at  short  intervals  by  the  contraction 
of  the  Orbicularis  muscle;  this  is  evidently  a  Spinal  action,  capable  of  being  in 
some  degree  restrained  (like  that  of  respiration)  by  the  will,  but  only  until 
such  times  as  the  stimulus  (resulting  perhaps  from  the  collection  of  minute 
particles  of  dust  upon  the  eyes,  or  from  the  dryness  of  their  surface  in  conse- 
quence of  evaporation)  becomes  too  strong  to  be  any  longer  resisted.  Again, 
we  have  in  sleep  or  in  apoplexy  an  example  of  this  purely  spinal  action,  un- 
balanced by  the  influence  of  the  will,  which,  in  the  waking  state,  antagonizes  it 
by  calling  the  levator  palpebrae  into  action.  As  soon  as  the  will  ceases  to  act, 
the  lids  droop,  and  close  over  the  eye  in  order  to  protect  it;  and  if  those  of  a 
sleeping  person  be  separated  by  the  hand,  they  will  be  found  presently  to 
return.  Here,  as  in  studying  the  respiratory  and  other  movements,  we  are  led 
to  perceive  that  it  is  the  Brain  alone  which  is  torpid  during  sleep,  and  whose 
functions  are  affected  by  this  torpidity.  As  Dr.  M.  Hall  very  justly  remarks, 
"the  Spinal  system  never  sleeps;"  it  is  constantly  in  activity;  and  it  is  thus 
that,  in  all  periods  and  phases  of  Life,  the  movements  which  are  essential  to  its 
continued  maintenance  are  kept  up  without  sensible  effort. — The  closure  of  the 
pupil  against  a  strong  light  is  another  movement  of  the  same  protective  tend- 
ency. The  channel  through  which  that  just  named  is  performed  is  completed 
by  the  first  branch  of  the  Fifth  arid  the  Portio  Dura  of  the  seventh.  The  con- 
traction of  the  pupil  is  immediately  caused  by  the  Third  pair,  or  Motor  Oculi, 
as  is  easily  shown  by  irritating  the  trunk  of  that  nerve  and  observing  the  result ; 
but  the  stimulus  which  excites  it  is  conveyed  through  the  Optic  nerve.  But 
although  the  contraction  of  the  pupil  is  usually  in  close  accordance  with  the 
sensation  occasioned  by  the  impression  of  light  upon  the  retina,  yet  there  is 
evidence  to  prove  that  the  sensation  of  light  is  not  always  necessary;  for,  even 
when  the  sight  of  both  eyes  has  been  entirely  destroyed  by  amaurosis,  the  regu- 
lar actions  have  been  witnessed  in  the  pupil,  in  accordance  with  varying  degrees 
of  light  impinging  on  the  retina.  Such  cases  seem  to  indicate  that  the  motion 
results  from  an  impression  upon  the  retina,  which  impression,  being  conducted 
to  the  Sensorium,  ordinarily  produces  a  sensation;  but  that  even  where  no  sen- 
sation is  produced,  on  account  of  a  disordered  state  of  the-  part  of  the  ganglionic 
centre  in  which  the  Optic  nerve  terminates,  if  the  central  tract  which  connects 
that  nerve  with  the  Third  pair  retain  its  integrity,  a  reflex  action  may  be  excited 
through  it,  although  no  sensation  intervene.  The  rarity  of  the  occurrence  is 
easily  accounted  for,  by  the  fact  that  in  most  cases  of  amaurosis,  the  disease  lies 
in  the  retina  or  in  the  trunk  of  the  nerve,  and  thereby  checks  both  its  spinal 
and  its  encephalic  actions. — Although  we  are  not  at  present  acquainted  with  any 
similar  protective  movements,  in  the  Human  being,  designed  to  keep  the  organ  of 
Hearing  from  injury,  yet  there  can  be  little  doubt  that  those  which  we  are  con- 
stantly witnessing  in  other  animals,  possessing  large  external  ears,  are  reflex 
actions  excited  by  the  irritation  applied  to  them.  In  regard  to  the  Nose,  we 
find  a  remarkably  complex  action — that  of  Sneezing — adapted  to  drive  off  any 
cause  of  irritation  (§  555).  The  stimulus  is  conveyed,  in  this  case,  not  through 
the  Olfactory  nerve,  but  through  the  Fifth  pair;  so  that  it  is  not  dependent 
upon  the  excitement  of  the  sensation  of  Smell.  The  act  of  Coughing,  also,  may 
be  regarded  as  of  a  protective  character;  being  destined  to  remove  sources  of 
irritation  from  the  air-passages.  Many  of  the  automatic  movements,  performed  by 
the  limbs  of  Frogs  and  other  animals,  when  their  connection  with  the  brain 
has  been  cut  off,  appear  destined  to  remove  these  parts  from  sources  of  irritation 
or  injury ;  and  they  may  thus  be  rightly  placed  under  the  same  category. 

725.  The  fact  that  sensation  is  very  commonly  associated  with  the  reflex 
actions  we  have  been  considering,  being  produced  by  the  impression  that  excites 
them,"  has  led  many  to  suppose  that  it  necessarily  participates  in  them ; — a 
doctrine  which  we  have  seen  to  be  untenable.  But  the  question  not  unnaturally 


098  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

arises,  why  Sensation  should  so  constantly  participate  in  these  operations,  if  not 
essential  to  them ;  and  the  answer  to  this  question  is  to  be  found  in  the  fact 
that  it  is  only  through  sensation  that  a  higher  set  of  actions,  mental  and  bodily, 
is  called  into  play,  which  is  essential  to  the  continued  maintenance  of  those 
belonging  to  the  present  category.  Illustrations  of  this  truth  might  be  drawn 
from  any  one  of  the  functions  already  noticed;  but  the  Ingestion  of  food  will 
supply  us  with  one  of  the  most  apposite.  We  have  seen  that  the  act  of  Deglu- 
tition is  in  itself  independent  of  sensation ;  anything  that  comes  within  the  grasp 
of  the  pharyngeal  constrictors  being  conveyed  downwards  by  their  reflex  con- 
traction, just  as  anything  which  touches  the  arms  of  a  Polype  is  entrapped  by 
them  and  drawn  into  the  stomach.  Now  this  action  may  be  considered  as 
attended  with  sensation,  in  the  ordinary  condition  of  the  higher  Animal,  in 
order  that  it  may  be  guided  in  the  performance  of  those  other  movements  of 
prehension,  mastication,  &c.,  by  which  the  food  may  be  brought  within  reach 
of  the  apparatus  of  deglutition ;  and  the  sensations  which  are  linked  with  these 
are  among  the  influences  which  prompt  to  those  mental  operations  whereby  food 
is  provided  for  the  digestive  apparatus  to  make  use  of.  The  Zoophyte  is  depend- 
ent for  its  supplies  of  aliment  upon  what  the  currents  in  the  surrounding  fluid,  or 
other  chances,  may  bring  into  its  neighborhood;  and  if  these  should  fail,  it 
starves.  The  encephalous  Infant,  again,  can  swallow,  and  even  suck;  but  it 
can  execute  no  other  movements  adapted  to  obtain  the  supply  of  food  continually 
necessary  for  maintenance,  because  it  has  not  a  mind  which  sensations  could 
awake  into  activity.  The  sensation  connected  with  excito-motor  actions  has 
not  only  this  important  end,  but  it  frequently  contributes  to  enjoyment,  as  in 
Suction  and  Ejaculatio  seminis.  The  sensation  accompanying  the  actions  of 
this  class,  moreover,  frequently  affords  premonition  of  danger,  or  gives  excite- 
ment to  supplementary  actions  destined  to  remove  it,  as  in  the  case  of  Respiration ; 
for  where  anything  interferes  with  the  due  discharge  of  the  function,  the  uneasy 
sensation  that  ensues  occasions  unwonted  movements,  which  are  more  or  less 
adapted  to  remove  the  impediment,  in  proportion  as  they  are  guided  by  judg- 
ment as  well  as  by  consciousness.  Again,  sensation  often  gives  warning  against 
inconvenience,  as  in  the  Excretory  functions;  and  here  it  is  very  evident  that 
its  purpose  is  not  only  (if  it  be  at  all)  to  excite  the  associated  muscles  necessary 
for  the  excretion,  but  actually  to  make  the  will  set  up  the  antagonizing  action 
of  the  sphincters  (§  434). 

726.  We  have  now  to  inquire  how  far  the  independent  action  of  the  Spinal 
Cord  is  concerned  in  the  general  muscular  movements  of  Man,  and  especially 
in  the  locomotive  actions  of  his  lower  extremities.  On  this  point  it  is  obvious 
that  we  must  not  be  guided  by  the  analogy  of  the  lower  animals ;  since  in  Man 
the  locomotive  and  other  movements  are  for  the  most  part  volitional  and  pur- 
posive, and  he  has  to  acquire  by  experience  that  control  over  his  muscular  appa- 
ratus which  is  necessary  to  enable  him  to  perform  them ;  whilst  in  Invertebrata 
generally,  and  in  a  large  part  of  the  lower  Vertebrata,  it  is  evident  that  the 
movements  of  progression,  &c.,  which  are  characteristic  of  each  species,  come 
under  the  general  category  of  automatic  actions,  and  are  provided  for  in  the 
original  organization  of  its  nervous  centres,  being  performed  without  any  edu- 
cation, and  under  circumstances  which  render  the  notion  of  a  purpose  on  the 
Animal's  own  part  quite  untenable.  In  so  far  as  these  instinctive  movements 
require  the  guidance  and  direction  of  sensations,  they  must  be  referred  to  the 
"  consensual"  group  ;  but  clear  evidence  is  afforded  by  the  continuance  of  many 
of  them  after  the  removal  of  the  centres  of  sensation,  that  they  are  excito-motor 
in  their  character,  and  that  they  require  no  higher  centre  than  the  ganglia 
which  correspond  to  the  Spinal  Cord  of  Man.1  There  can  be  little  doubt  that 

1  See"Princ.  of  Phys.,  Gen.  and  Comp.,"gg  769-771,  Am.  Ed. 


FUNCTIONS   OF   THE    SPINAL   CORD. 

the  habitual  movements  of  locomotion,  and  others  which  have  become  "  second- 
arily automatic,"  may  be  performed  by  Man  under  particular  circumstances 
through  the  agency  of  the  Spinal  Cord  alone,  under  the  guidance  and  direction 
of  the  Sensorial  centres,  or  even  without  such  guidance  ;  the  required  condition 
being,  that  the  influence  of  the  Cerebrum  shall  be  entirely  withdrawn.  There 
are  numerous  instances  on  record,  in  which  soldiers  have  continued  to  march  in 
a  sound  sleep ;  and  the  Author  has  been  assured  by  an  intelligent  witness,  that 
he  has  seen  a  very  accomplished  pianist  complete  the  performance  of  a  piece  of 
music  in  the  same  state.1  A  case  has  been  mentioned  to  him  by  his  friend  Dr. 
William  Budd,  of  a  patient  who  labored  under  that  form  of  epilepsy  in  which 
there  was  simply  a  temporary  suspension  of  consciousness  without  convulsion  ; 
and  whenever  the  paroxysm  came  on,  he  persisted  in  the  kind  of  movement  in 
which  he  was  engaged  at  the  moment,  having  on  one  occasion  fallen  into  the 
water  through  continuing  to  walk  onwards,  and  having  on  several  occasions 
(being  a  shoemaker  by  trade)  wounded  his  fingers  with  the  awl  in  his  hand  by  a 
repetition  of  the  movement  by  .which  he  was  endeavoring  to  pierce  the  leather. 
Such  facts  as  these  add  great  strength  to  the  probability,  that  when  the  Cere- 
bral power  is  not  suspended,  but  merely  directed  into  another  channel,  as  in  the 
states  of  reverie  or  abstraction,  and  the  attention  is  entirely  drawn  off  from  the 
movements  of  locomotion,  the  continuance  of  these  is  due  to  the  independent 
automatic  action  of  the  Spinal  Cord,  the  direction  being  given  to  them  by  the 
Sensory  Granglia.  This  point,  however,  will  be  more  fully  considered  hereafter 
(§  749);  at  present  it  may  be  remarked  that,  when  a  regular  train  of  move- 
ments is  being  performed  under  such  conditions,  each  action  may  be  probably 
regarded  as  affording  the  stimulus  to  the  next ;  each  contact  of  the  foot  with 
the  ground,  in  the  act  of  walking,  exciting  the  muscular  contractions  which  con- 
stitute the  next  step  f  and  each  movement  of  the  musician  exciting  that  which 
has  customarily  followed  it,  after  the  same  fashion.  Now  in  all  these  cases, 
it  seems  reasonable  to  infer,  that  the  same  kind  of  connection  between  the  ex- 
citor  and  motor  nerves  comes  to  be  formed  by  a  process  of  gradual  development, 
as  originally  exists  in  the  nervous  systems  of  those  animals  whose  movements 
are  entirely  automatic.  Whether  there  is  in  any  case  an  actual  continuity  of 
nerve-fibres,  may  be  reasonably  doubted.  That  such  a  peculiar  continuity  is  not 
requisite,  in  order  to  allow  an  excitor  impression  made  upon  one  part  of  the 
Cord  to  call  forth  motions  through  another,  may  be  certainly  inferred  from  the 
fact,  that  under  particular  circumstances  we  find  the  influence  of  such  impres- 
sions radiating  in  every  direction,  and  extending  to  nerves  which  they  do  not 
ordinarily  affect  (§  728).  Still  there  can  be  no  doubt  that  the  nerve-force  is 
disposed  to  pass  in  special  tracks  ;  and  it  seems  probable  that,  whilst  some  are 
originally  marked  out  for  the  automatic  movements,  others  may  be  gradually 
worn  in  (so  to  speak)  by  the  habitual  action  of  the  Will ;  and  that  thus,  when 
a  train  of  sequential  actions  originally  directed  by  the  Will  has  been  once  set  in 
operation,  it  may  continue  without  any  further  influence  from  that  source. 

727.  Another  manifestation  of  the  independent  power  of  the  Spinal  Cord  is 
seen  in  its  influence  on  Muscular  Tension. — The  various  muscles  of  the  body, 
even  when  there  is  the  most  complete  absence  of  effort,  maintain,  in  the  healthy 

1  In  playing  by  memory  on  a  musical  instrument,  the  muscular  sense  often  suggests  the 
sequence  of  movements  with  more  certainty  than  the  auditory  ;  and  since  the  impressions 
derived  from  the  muscles  may  prompt  and  regulate  successional  movements  without  affect- 
ing the  consciousness,  there  is  no  such  improbability  in  the  above  statement  as  might  at 
first  sight  appear. 

2  The  truth  of  this  view  seems  to  the  Author  to  be  strongly  supported  by  observation 
of  the  mode  in  which  infants  learn  to  walk;  for,  long  before  they  can  stand,  they  will  in- 
stinctively perfoi'm  the  movements  of  walking,  if  they  be  so  supported  that  the  feet  touch 
the  ground. 


700  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

state  of  the  system,  a  certain  degree  of  firmness,  by  their  antagonism  with  each 
other ;  and  if  any  set  of  muscles  be  completely  paralyzed,  the  opposing  muscles 
will  draw  the  part  on  which  they  act  out  of  its  position  of  repose ;  as  is  well 
seen  in  the  distortion  of  the  face  which  is  characteristic  of  paralysis  of  the  facial 
nerve  on  one  side.  This  condition  has  been  designated  as  the  tone  of  the 
Muscles;  but  this  term  renders  it  liable  to  be  confounded  with  their  tonic 
contraction  (§  331),  which  is  also  concerned  in  maintaining  their  firmness,  but 
which  is  a  manifestation  of  the  simple  contractility  of  their  tissue,  and  is  exhi- 
bited alike  by  the  striated  and  the  non-striated  forms  of  muscular  fibre,  but 
more  especially  by  the  latter.  On  the  other  hand,  the  condition  now  alluded 
to,  which  may  perhaps  be  appropriately  termed  their  tension,  is  the  result  of  a 
moderate  though  continued  excitement  of  that  contractility,  through  the  nervous 
centres.  It  has  been  proved  by  Dr.  M.  Hall  that  the  Muscular  Tension  is  not 
dependent  upon  the  influence  of  the  Brain,  but  upon  that  of  the  Spinal  Cord  j 
as  the  following  experiments  demonstrate  :  "  Two  Rabbits  were  taken ;  from 
one  the  head  was  removed ;  from  the  other  also  the  head  was  removed,  and  the 
spinal  marrow  was  cautiously  destroyed  with  a  sharp  instrument :  the  limbs  of 
the  former  retained  a  certain  degree  of  firmness  and  elasticity;  those  of  the 
second  were  perfectly  lax/'  Again :  "  The  limbs  and  tail  of  a  decapitated 
Turtle  possessed  a  certain  degree  of  firmness  or  tone,  recoiled  on  being  drawn 
from  their  position,  and  moved  with  energy  on  the  application  of  a  stimulus. 
On  withdrawing  the  spinal  marrow  gently  out  of  its  canal,  all  these  phenomena 
ceased.  The  limbs  were  no  longer  obedient  to  stimuli,  and  became  perfectly 
flaccid,  having  lost  all  their  resilience.  The  sphincter  lost  its  circular  form  and 
contracted  state,  becoming  lax,  flaccid,  and  shapeless.  The  tail  was  flaccid,  and 
unmoved  on  the  application  of  stimuli."1  It  is  further  remarked,  by  Messrs. 
Todd  and  Bowman,  that  "  a  decapitated  frog  will  continue  in  the  sitting  posture 
through  the  influence  of  the  spinal  cord ;  but  immediately  this  organ  is  removed, 
the  limbs  fall  apart." — This  operation  of  the  Spinal  Cord  is  doubtless  but  a 
peculiar  manifestation  of  its  ordinary  reflex  function.  We  shall  hereafter  see 
(§  750)  how  much  the  influence  of  the  Will  in  producing  the  active  contraction 
of  a  muscle  is  connected  with  sensations  received  from  it ;  and  it  seems  highly 
probable  that  the  impression  of  the  state  of  the  muscle,  conveyed  by  the  afferent 
fibres  proceeding  from  it  to  the  spinal  cord,  is  sufficient  to  excite  this  state  of 
moderate  tension  through  the  motor  nerves  arising  from  the  latter.  Such  a 
view  derives  probability  from  the  fact,  which  must  have  fallen  under  the  ob- 
servation of  almost  every  one,  that  most  reflex  actions  become  increased  in 
energy  if  resistance  be  made  to  them.  Of  this  we  have  familiar  examples  in 
the  action  of  the  expulsor  muscles,  which  operate  in  defecation,  urination,  and 
parturition,  if,  when  they  are  strongly  excited,  their  efforts  be  opposed  by 
spasmodic  contraction  of  the  sphincters,  or  by  mechanical  means.  Many  forms 
of  convulsive  movement  exhibit  the  same  tendency,  their  violence  being  pro- 
portional to  the  mechanical  force  used  to  restrain  them.3  Here  it  is  evident 
that  the  impression  of  resistance,  conveyed  to  the  Spinal  Cord,  is  the  source  of 
the  increased  energy  of  its  motor  influence ;  from  which  we  may  fairly  infer 
that  the  moderate  resistance,  occasioned  by  the  natural  antagonism  of  the  muscles, 
is  the  source  of  their  continued  and  moderate  tension,  whilst  they  are  under  the 
influence  of  the  Spinal  Cord.  This  constant  though  gentle  action  serves  to  keep 
up  the  nutrition  of  the  muscles,  which  are  paralyzed  to  the  will ;  and  this  is 
still  more  completely  maintained,  if  the  porton  of  the  nervous  centres,  with 

1  "  Memoirs  on  the  Nervous  System,"  1837,  p.  93. 

2  Hence  the  absurdity  of  the  common  practice  of  endeavoring  to  prevent  the  movements 
of  the  limbs  and  body,  in  convulsive  paroxysms,  by  mechanical  constraint.     Nothing  should 
be  attempted  but  what  is  requisite  to  prevent  the  sufferer  from  doing  himself  an  injury. 


FUNCTIONS   OF   THE   SPINAL   CORD.  701 

which  they  remain  connected,  be  so  unduly  irritable,  that  the  muscles  are  called 
into  contraction  upon  the  slightest  excitation,  and  are  thus  continually  exhi- 
biting twitchings,  startings,  or  more  powerful  convulsive  movements.  It  is 
upon  the  state  of  nutrition  of  the  muscles  that  their  contractility  depends 
(§  313) ;  and  hence  the  Spinal  Cord  has  an  indirect  influence  upon  this  peculiar 
property,  which  is  more  likely  to  be  retained,  when  the  muscle  is  still  subject 
to  the  influence  of  the  Spinal  Cord,  though  cut  off  from  that  of  the  Brain,  than 
when  it  is  completely  paralyzed  by  the  entire  separation  of  its  connection  with 
the  nervous  centres. 

728.  The  functional  activity  of  the  Spinal  Cord  is  capable  of  being  morbidly 
diminished  or  augmented.  It  may  even  be  for  a  time  almost  completely  sus- 
pended, as  in  Syncope ;  which  state  may  be  induced  by  sudden  and  violent 
impressions,  either  of  a  mental  or  physical  nature,  that  operate  upon  the  whole 
nervous  system  at  once — commencing,  however,  in  the  Brain.  It  is  to  be 
remarked  that,  in  recovering  from  these,  it  is  the  Spinal  system  of  which  the 
activity  is  first  renewed;  the  respiratory  movements  recommencing,  and  the 
power  of  swallowing  being  restored,  before  any  voluntary  actions  can  be  per- 
formed. A  corresponding  state  may  be  induced  in  particular  portions  of  the 
system  by  Concussion ;  as  is  seen  in  severe  injuries  of  the  Spinal  Cord,  which 
are  almost  invariably  followed  for  a  time  by  the  suspension  of  its  functions. 
Again,  the  power  of  the  whole  Spinal  Cord  may  be  diminished  by  various 
causes,  such  as  enfeebled  circulation,  pressure,  &c. ;  and  then  we  have  torpidity 
and  imperfect  nutrition  of  the  whole  muscular  system.1  If  oppression  exist  in 
the  Brain,  the  functions  of  the  Medulla  Oblongata  will  be  especially  affected ; 
and  if  it  be  prolonged  and  sufficiently  severe,  Asphyxia  will  result  from  the 
interruption  of  the  respiratory  movements  which  it  occasions. — On  the  other 
hand,  the  excitability  of  the  whole  Cord,  or  of  particular  parts  of  it,  may  be 
morbidly  increased.3  This  is  especially  seen  in  ordinary  Tetanus,  and  in  the 

1  A  case  has  been  for  some  time  under  the  Author's  observation,  in  which  the  males  of  a 
family  have  been  successively  aifectcd  with  a  general  muscular  debility,  commencing  in  the 
lower  extremities,  which  is  pretty  obviously  traceable  to  deficient  functional  activity  of  the 
Spinal  Cord.     The  affection  has  manifested  itself  during  the  earlier  years  of  childhood  ;  and 
in  the  two  elder  sons  has  advanced  until  it  has  produced  an  almost  complete  general  paralysis, 
with  fatty  degeneration  of  the  muscles.     In  a  younger  son,  in  whom  the  same  affection  had 
distinctly  begun  to  manifest  itself,  it  has  been  kept  in  check  by  very  careful  attention  to 
every  means  that  can  favor  healthy  nutrition  and  development  of  nervous  power ;  among 
which,  constant  exercise,  and  the  frequent  transmission  of  feeble  electrical  currents  down 
the  spine  and  from  the  spine  to  the  limbs,  have  seemed  the  most  effectual. 

2  It  has  been  pointed  out  by  Messrs.  Todd  and  Bowman  ("Physiological  Anatomy," 
p.  281,  Am.  Ed.}  that  the  Spinal  Cord  of  the  male  frog,  at  the  season  of  copulation,  naturally 
possesses  a  state  of  most  extraordinary  excitability.     The  thumb  of  each  anterior  extremity, 
at  this  season,  becomes  considerably  enlarged ;  as  is  well  known  to  Naturalists.     "This 
enlargement  is  caused  principally  by  a  considerable  development  of  the  papillary  structure 
of  the  skin  which  covers  it ;  so  that  large  papillas  are  formed  all  over  it.     A  male  frog,  at 
this  season,  has  an  irresistible  propensity  to  cling  to  any  object,  by  seizing  it  between  his 
anterior  extremities.     It  is  in  this  way  that  he  seizes  upon,  and  clings  to  the  female ;  fixing 
his  thumbs  to  each  side  of  her  abdomen,  and  remaining  there  for  weeks,  until  the  ova  have 
been  completely  expelled.     An  effort  of  the  Will  alone  could  not  keep  up  the  grasp  unin- 
terruptedly for  so  long  a  time  ;  yet  so  firm  is  the  hold,  that  it  can  with  difficulty  be  relaxed. 
"Whatever  is  brought  in  the  way  of  the  thumbs,  will  be  caught  by  the  forcible  contraction 
of  the  anterior  limbs ;  and  hence  we  often  find  frogs  clinging  blindly  to  a  piece  of  wood,  or 
a  dead  fish,  or  some  other  substance  which  they  may  chance  to  meet  with.     If  the  finger 
be  placed  between  the  anterior  extremities,  they  will  grasp  it  firmly ;  nor  will  they  relax 
their  grasp  until  they  are  separated  by  force.     If  the  animal  be  decapitated,  whilst  the 
finger  is  within  the  grasp  of  its  anterior  extremities,  they  still  continue  to  hold  on  firmly. 
The  posterior  half  of  the  body  may  be  cut  away,  and  yet  the  anterior  extremities  will  still 
cling  to  the  finger ;  but  immediately  that  the  segment  of  the  cord,  from  which  the  anterior 
extremities  derive  their  nerves,  has  been  removed,  all  their  motion  ceases.     This  curious 
instinct  only  exists  during  the  period  of  sexual  excitement ;  for  at  other  periods  the  excita- 
bility of  the  anterior  extremities  is  considerably  less  than  that  of  the  posterior." 


702  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

artificial  Tetanus  induced  by  Strychnine;  in  which  the  slightest  external 
stimulus  is  sufficient  to  induce  reflex  actions  in  their  most  terrific  forms.  It  is 
interesting  to  remark  that,  in  this  formidable  disease,  the  functions  of  the 
muscles  controlling  the  various  orifices  are  those  most  affected ;  and  it  is  by  the 
spasms  affecting  the  organs  of  respiration  or  deglutition,  that  life  is  commonly 
terminated.  In  some  forms  of  Hysteria,  also,  there  is  a  morbid  excitability  of 
the  same  kind,  so  that  various  kinds  of  convulsions  are  brought  on  by  very 
slight  stimuli ;  and  Infantile  convulsions  are  generally  attributable  to  the  same 
kind  of  disorder  of  the  nervous  centres,  which  is  frequently  induced  by  bad  air, 
unwholesome  food,  or  some  other  cause  that  affects  the  purity  of  the  blood 
(§  583).  Not  only  is  the  general  muscular  system  of  Animal  life  involved  in 
these  abnormal  actions,  but  various  parts  of  the  apparatus  of  Organic  life  have 
their  normal  functions  seriously  perverted  by  the  same  condition  of  the  Spinal 
Cord ;  being  connected  with  it  through  the  medium  of  the  Sympathetic  system 
of  nerves,  whose  motor  powers  are  chiefly,  if  not  entirely,  derived  from  that 
source  (Sect.  6). — Various  remedial  agents  will  probably  be  found  to  operate, 
by  occasioning  increased  excitability  in  some  particular  segments  of  the  Cord ; 
so  that  the  usual  stimuli  applied  to  the  parts  connected  with  these  will  occasion 
increased  muscular  tension.  This  seems  to  be  the  case,  for  example,  in  regard 
to  the  influence  of  aloes  on  the  rectum  and  uterus,  cantharides  on  the  neck  of 
the  bladder  and  adjoining  parts,  and  secale  cornutum  on  the  uterus.  The  mode 
of  influence  of  cantharides  is  illustrated  by  a  curious  case,  related  by  Dr.  M. 
Hall,  of  a  young  lady  who  lost  the  power  of  retention  of  urine,  in  consequence  of 
a  fatty  tumor  in  the  spinal  canal,  which  gradually  severed  the  Spinal  Cord,  and 
induced  paraplegia.  The  power  of  retaining  the  urine  was  always  restored  far 
a  time  by  a  dose  of  tincture  of  cantharides,  which  seems  to  have  acted  by 
augmenting  the  excitability  of  that  segment  of  the  Cord  with  which  the  sphinc- 
ter vesicse  is  connected. 

3. —  Of  the  Sensory  Ganglia  and  their  Functions. —  Consensual  Movements. 

729.  At  the  base  of  the  Brain  in  Man,  concealed  by  the  Cerebral  Hemi- 
spheres, but  still  readily  distinguishable  from  them,  we  find  a  series  of  ganglionic 
masses;  which  are  in  direct  connection  with  the  nerves  of  Sensation;  and  which 
appear  to  have  functions  quite  independent  of  those  of  the  other  components  of 
the  Encephalon. — Thus  anteriorly  we  have  the  Olf active  ganglia,  in  what  are 
commonly  termed  the  bulbous  expansions  of  the  Olfactive  nerve.  That  these 
are  real  ganglia  is  proved  by  their  containing  gray  or  vesicular  substance;  and 
their  separation  from  the  general  mass  of  the  Encephalon,  by  the  peduncles  or 
footstalks  commonly  termed  the  trunks  of  the  Olfactory  nerves,  finds  its  analogy 
in  many  species  of  Fish.  The  ganglionic  nature  of  these  masses  is  more  evident 
in  many  of  the  lower  Mammalia,  in  which  the  organ  of  Smell  is  highly  developed, 
than  it  is  in  Man,  whose  olfactive  powers  are  comparatively  moderate. — At  some 
distance  behind  these,  we  have  the  representatives  of  the  Optic  ganglia,  in  the 
Tubercula  Quadrigemina,  to  which  the  principal  part  of  the  roots  of  the  Optic 
nerve  may  be  traced.  Although  these  bodies  are  so  small  in  Man,  in  compari- 
son with  the  whole  Encephalic  mass,  as  to  be  apparently  insignificant,  yet  they 
are  much  larger,  and  form  a  more  evidently  important  part  of  it  in  many  of  the 
lower  Mammalia;  though  still  presenting  the  same  general  aspect. — The  Audi- 
tory ganglia  do  not  form  distinct  lobes  or  projections ;  but  are  lodged  in  the 
substance  of  the  Medulla  Oblongata.  Their  real  character  is  most  evident  in 
certain  Fishes,  as  the  Carp ;  in  which  we  trace  the  Auditory  nerve  into  a  gan- 
glionic centre  as  distinct  as  the  Optic  ganglion.  In  higher  animals,  however, 
and  in  Man,  we  are  able  to  trace  the  Auditory  nerve  into  a  small  mass  of  vesi- 
cular matter,  which  lies  on  each  side  of  the  Fourth  Ventricle;  and  although  this 


SENSORY   GANGLIA.  —  CONSENSUAL   ACTIONS.  703 

is  lodged  in  the  midst  of  parts  whose  function  is  altogether  different,  yet  there 
seems  no  reason  for  doubting  that  it  has  a  character  of  its  own,  and  that  it  is 
really  the  ganglionic  centre  of  the  Auditory  nerve. — In  like  manner,  we  may 

Fig.  189. 


Section  of  the  cerebrum,  displaying  the  surfaces  of  the  corpora  striata,  and  optic  thalami,  the  cavity  of  the 
third  ventricle,  and  the  upper  surface  of  the  cerebellum.— a  e.  Corpora  quadrigemina,— a  testis,  e  nates. 
b.  Soft  commissure,  c.  Corpus  callosum.  /.  Anterior  pillars  of  fornix.  g.  Anterior  cornu  of  lateral  ventricle. 
kk.  Corpora  striata.  IL  Optic  thalami.  *  Anterior  tubercle  of  the  left  thalamus.  z  to  s.  Third  ventricle.  In 
front  of  z,  anterior  commissure.  5.  Soft  commissure,  s.  Posterior  commissure,  p.  Pineal  gland  with  its 
peduncles,  n  n,  Processus  a  cerebello  ad  testes.  m  m.  Hemispheres  of  the  cerebellum.  It.  Superior  vermiform 
process.  L  Notch  behind  the  cerebellum. 

probably  fix  upon  a  collection  of  vesicular  matter,  imbedded  in  the  Medulla  Ob- 
longata — which  is  considered  by  Stilling  to  be  the  nucleus  of  the  G-losso-pharyn- 
geal  nerve,  and  to  which  a  portion  of  the  sensory  root  of  the  Fifth  pair  may  be 
also  traced — as  representing  the  Gustatory  ganglion. 

730.  At  the  base  of  the  Cerebral  Hemispheres,  we  find  two  other  large  gan- 
glionic masses,  on  either  side ;  through  which  nearly  all  the  fibres  appear  to  pass 
that  connect  the  Hemispheres  with  the  Medulla  Oblongata.  These  are  the 
Thalami  Optici  and  the  Corpora  Striata.  Now,  although  these  are  commonly 
in  the  light  of  appendages,  merely,  to  the  Cerebral  Hemispheres,  it  is  evident, 
from  the  large  quantity  of  vesicular  matter  they  contain,  that  they  must  rank 
as  independent  ganglionic  centres;  and  this  view  is  supported  alike  by  the  evi- 
dence of  Comparative  Anatomy,  and  by  that  afforded  by  the  history  of  Develop- 
ment. For  it  is  certain  that  the  size  of  the  Thalami  Optici  and  Corpora  Striata 
presents  no  more  relation,  in  different  tribes  of  animals,  to  that  of  the  Cerebrum, 
than  does  that  of  the  ganglia  of  Special  Sense ;  and  they  may  even  present  a 
considerable  development,  when  the  condition  of  the  Cerebrum  is  quite  rudi- 
mentary. Thus  in  the  Osseous  Fishes,  a  careful  examination  of  the  rela- 
tions of  the  body  which  is  known  as  the  Optic  lobe  (Fig.  171,  c)  makes  it  ap- 


704 


OP  THE  FUNCTIONS  OP  THE  NERVOUS  SYSTEM. 


parent  that  this  is  not  merely  the  representative  of  the  proper  Optic  G-anglion  of 
Man,  but  also  of  the  Thalamus  Options;  whilst,  again,  the  mass  which  is  desig- 
nated as  the  Cerebral  lobe  (B)  is  chiefly  homologous  with  the  Corpus  Striatum 
of  higher  animals.  The  nature  of  the  latter  body  is  made  apparent  in  the  higher 
Cartilaginous  Fishes,  by  the  presence  of  a  ventricle  in  its  interior ;  the  floor  of 
this  cavity  being  formed  by  the  Corpus  Striatum,  whilst  the  thin  layer  of 
nervous  matter  which  forms  its  roof  is  the  only  representative  of  the  Cerebral 

[Fig.  189*. 


A.  Dissection  of  a  brain  which  had  been  hardened  in  spirits  of  -wine.  It  represents  the  base  of  the 
brain  with  the  course  of  the  fibres  from  the  pyramidal  or  motor  columns,  on  the  left  side  expdled  con- 
tinuously from  the  pyramidal  body  (T),  through  the  pons  Varolii  (x),  which  has  been  partly  removed  on  that 
side,  forming  (u)  the  under  part  of  the  crus  cerebri,  plunging  to  the  corpus  striatuin  (M),  emerging  (mm  mm) 
from  thence,  and  running  forwards,  forwards  and  outwards,  outwards  and  backwards,  to  the  whole  extent  of 
the  hemispherical  ganglion  (B  B  B).  The  course  of  some  of  the  fibres  of  the  superior  longitudinal  commissure, 
and  also  some  of  the  fibres  of  the  great  commissure,  are  shown.  B  B  B.  Convoluted  surface  of  the  brain,  or 
hemispherical  ganglion.  K.  Thalamus  optici  divided.  L  N,  L  N.  Anterior  cornua  of  the  lateral  ventricle 
separated  by  N,  septum  lucidum.  M  M.  Corpora  striata.  N.  Anterior  pillars  of  the  fornix  running  from  the 
c  a,  corpora  albicantia.  p  p.  Posterior  extremity  and  under  surface  of  the  great  transverse  commissure,  or 
corpus  callosum.  p  p.  Fibres  continued  to  the  posterior  lobe.  A  p.  Anterior  extremity  of  ditto.  8.  Corpus 
olivare.  T.  Corpus  pyrarnidale.  u  u.  Crura  cerebri.  w  w.  Corpus  restiforme.  x  x.  Pons  Varolii ;  a?,  divided 
end  of  it,  where  it  enters  the  cerebellum,  a  c.  Anterior  commissure,  divided  a  little  to  the  right  of  the 
mesial  line.  g.  Groove  in  the  corpus  striatum,  from  which  it  has  been  removed,  c.  Third  pair  of  nerves. 
/*,/*.  Fissura  Sylvii.  h  n.  Descending  fibres  of  the  fornix  over  the  hippocampal  convolution.1— ED.] 

1  ["Solly  oil  the  Brain,"  Am.  Ed.} 


FUNCTIONS    OF   THE    SPINAL   CORD.  705 

hemisphere.  So  in  the  Human  embryo  of  the  6th  week,  we  find  a  distinct 
vesicle  for  the  Thalami  Optici,  interposed  between  the  vesicle  of  the  Corpora 
Quadrigemina  and  that  which  gives  origin  to  the  Cerebral  Hemispheres;  whilst 
the  Corpora  Striata  constitute  the  floor  of  the  cavity  or  ventricle  which  exists 
in  the  latter,  this  being  as  yet  of  comparatively  small  dimensions.  Now, 
as  already  pointed  out,  we  may  distinguish  in  the  Medulla  Oblongata  and 
Crura  Cerebri,  a  sensory  and  motor  tract,  by  the  endowments  of  the  nerves  which 
issue  from  them.  The  sensory  tract  maybe  traced  upwards,  untilit  almost  entirely 
spreads  itself  through  the  substance  of  the  Thalamus.  Moreover,  the  Optic 
nerves,  and  the  peduncles  of  the  Olfactive,  may  be  shown  to  have  a  distinct 
connection  with  the  Thalami ;  the  former  by  the  direct  passage  of  a  portion  of 
their  roots  into  these  ganglia;  and  the  latter  through  the  medium  of  the  Fornix. 
Hence  we  may  fairly  regard  the  Thalami  Optici  &$  the  chief  focus  of  the  Sensory 
nerves,  and  more  especially  as  the  ganglionic  centre  of  the  nerves  of  common 
sensation,  which  ascend  to  it  from  the  Medulla  Oblongata  and  Spinal  Cord. — 
On  the  other  hand,  the  Corpora  Striata  are  implanted  on  the  Motor  tract  of  the 
Crura  Cerebri,  which  descend  into  the  Pyramidal  columns ;  and  their  relation 
to  the  fibres  of  which  that  tract  is  composed  appears  to  be  essentially  the  same 
as  that  which  the  Thalami  bear  to  the  sensory  tract.  Upon  the  precise  nature 
of  that  relation,  Anatomists  are  not  agreed ;  but  there  are  several  considerations 
which  render  it  probable  that  there  is  not  that  continuity  between  the  fibres  of 
the  Crura  Cerebri,  and  those  which  radiate  from  the  Thalami  Optici  and  Corpora 
Striata  to  the  surface  of  the  Hemispheres,  which  a  superficial  examination  would 
seem  to  indicate ;  but  that  the  fibres  which  ascend  from  the  Crura  Cerebri  for 
the  most  part,  if  not  entirely,  terminate  in  the  vesicular  substance  of  the  former 
bodies,  and  that  the  radiating  fibres  of  the  latter  take  a  fresh  departure  from 
them.1  At  any  rate,  as  we  shall  see  hereafter,  there  is  a  complete  physiological 
separation  between  the  Cerebrum  and  the  Sensory  Ganglia  upon  which  it  is 
superposed. 

731.  The  Thalami  Optici,  and  the  Corpora  Striata,  as  is  well  known,  are  very 
closely  connected  with  each  other  by  commissural  fibres;  and,  if  the  preceding 
account  of  their  respective  offices  be  correct,  they  may  be  regarded  as  having 
much  the  same  relation  to  each  other  as  that  which  exists  between  the  pos- 
terior and  anterior  peaks  of  vesicular  matter  in  the  Spinal  Cord  f  the  latter 
issuing  motor  impulses  in  respondence  to  sensations  excited  through  the  former. 
They  are  also  closely  connected  with  other  ganglionic  masses  in  their  neighbor- 
hood, such  as  the  Locus  Niger,  and  the  vesicular  matter  of  the  Tuber  Annulare ; 
which  again  are  in  close  relation  with  the  vesicular  matter  of  the  Medulla 
Oblongata. — Altogether  it  is  very  evident  that  a  series  of  true  ganglionic  cen- 
tres exists  at  the  base  of  the  Encephalon,  and  that  these  are  really  as  distinct 
from  either  the  Cerebrum  or  Cerebellum  as  the  latter  are  from  each  other;  and 
we  have  next  to  inquire,  what  functions  are  to  be  assigned  to  them. 

73$.  The  determination  of  these  may  seem  to  be  the  more  difficult,  as  it  is 
impossible  to  make  any  satisfactory  experiments  upon  the  ganglionic  centres  in 
question  by  isolating  them  completely  from  the  Cerebral  Hemispheres  above, 
and  from  the  Medulla  Oblongata  and  Spinal  Cord  below.  But  the  evidence 
derived  from  Comparative  Anatomy  appears  to  be  in  this  case  particularly 
clear;  and,  rightly  considered,  affords  us  nearly  all  the  information  we 
require.  In  the  series  of  "experiments  prepared  for  us  by  nature,"  which 
is  presented  to  us  in  the  descending  scale  of  Animal  life,  we  witness  the  effects 

1  See  especially  Messrs.  Todcl  and  Bowman's  "Physiological  Anatomy,"  p.  251,  Am.  Ed., 
and  Prof.  Kolliker's  "  Mikroskopische  Anatomic,"  band  ii.  g  118. 

2  This  was  first  pointed  out  by  Messrs.  Todd  and  Bowman  in  their  "Physiological 
Anatomy,"  p.  308,  Am.  Ed. 

45 


706  Or   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

of  the  gradual  change  in  the  relative  development  of  the  Sensory  gan- 
glia and  Cerebral  Hemispheres,  which  are  presented  to  us  in  the  Vertebrated 
classes ;  and  the  results  of  the  entire  withdrawal  of  the  latter,  and  of  the  sole 
operation  of  the  former,  which  are  presented  in  the  higher  Invertebrata.  For 
the  sensory  ganglia  gradually  increase,  whilst  the  Cerebral  Hemispheres  as 
regularly  diminish,  in  relative  size  and  importance,  as  we  descend  from  the 
higher  Mammalia  to  the  lower — from  these  to  Birds — thence  to  reptiles — from 
these,  again,  to  the  higher  Fishes,  in  which  the  aggregate  size  of  the  Sensory 
ganglia  equals  that  of  the  Cerebrum — thence  to  the  lower  Fishes,  in  which  the 
size  of  the  Cerebral  lobes  is  no  greater  than  that  of  a  single  pair  of  sensory 
ganglia,  the  Optic,  and  frequently  even  inferior — and  lastly,  to  the  Amphioxus 
or  Lancelot,  the  lowest  Vertebrated  animal  of  which  we  have  any  knowledge, 
in  which  there  is  not  the  rudiment  of  a  Cerebrum,  the  Encephalon  being  only 
represented  by  a  single  ganglionic  mass,  which,  from  its  connection  with  the 
nerves  of  sense,  must  obviously  be  regarded  as  analogous  to  the  congeries  of 
ganglia  that  we  find  in  the  higher  forms  of  the  class. — Descending  to  the  In- 
vertebrated  series,  we  find  that,  except  in  a  few  of  those  which  border  most 
closely  upon  Vertebrata  (such,  for  example,  as  the  Cuttle-Fish),  the  whole  Cepha- 
lic mass  appears  to  be  made  up  of  ganglia  in  immediate  connection  with  the 
Nerves  of  Sense.  These  may  appear  to  form  but  a  single  pair ;  yet  they  are  in 
reality  composed  of  several  pairs,  fused  (as  it  were)  into  one  mass.  Of  this  we 
may  judge  by  determining  the  number  of  distinct  pairs  of  nerves  which  issue 
from  them ;  and  also  by  the  investigation  of  the  history  of  their  development, 
the  results  of  which  bear  a  close  correspondence  with  those  obtained  in  the 
preceding  method. — It  is  further  to  be  remarked  that  the  development  of  the 
Cephalic  ganglia  in  the  Invertebrata  always  bears  an  exact  proportion  to  the 
development  of  the  eyes;  the  other  organs  of  special  sense  being  comparatively 
undeveloped;  whilst  these,  in  all  the  higher  classes  at  least,  are  instruments 
of  great  perfection,  and  are  evidently  connected  most  intimately  with  the 
direction  of  the  movements  of  the  animals.  Of  this  fact  we  have  a  remarkable 
illustration  in  the  history  of  the  metamorphosis  of  Insects;  the  eyes  being 
almost  rudimentary,  and  the  Cephalic  ganglia  comparatively  small,  in  most 
Larvae;  whilst  both  these  organs  attain  a  high  development  in  the  Imago,  to 
whose  actions  the  faculty  of  sight  is  essential.1 

733.  Thus  we  are  led  by  the  very  cogent  evidence  which  Comparative  Ana- 
tomy supplies,  to  regard  this  series  of  Ganglionic  centres  as  constituting  the 
real  Sensorium  ;  each  ganglion  having  the  power  of  communicating  to  the  mind 
the  impressions  derived  from  the  organ  with  which  it  is  connected,  and  of  excit- 
ing automatic  muscular  movements  in  respondence  to  these  sensations.     If  this 
position  be  denied,  we  must  either  refuse  the  attribute  of  consciousness  to  such 
animals  as  possess  no  other  encephalic  centres  than  these ;  or  we  must  believe 
that  the  addition  of  the  Cerebral  hemispheres,  in  the  Vertebrated  series,  alters  the 
endowments  of  the  Sensory  ganglia — an  idea  which  is  contrary  to  all  analogy. 

734.  So  far  as  the  results  of  Experiments  can  be  relied  on,  they  afford  a  cor- 
roboration  of  this  view.     The  degree  in  which  animals  high  in  the  scale  of  or- 
ganization can  perform  the  functions  of  life,  without  any  other  centre  of  action 
than  the  Ganglia  of  Special  sense,  the  Medulla  Oblongata,  and  the  Cerebellum, 
appears  extraordinary  to  those  who  are  accustomed  to  regard  the  Cerebral  Hemi- 
spheres as  the    centre  of  all  energy.     From    the  experiments  of  Flourens,a 
Hertwig,3  Magendie,4  Longet,5  and  others,  it  appears  that  not  only  Reptiles,  but 

1  See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  CHAP.  xx.  Sect.  2,  An^.  Ed. 

2  "  Recherches  Experimentales  sur  les  propriete's  et  les  fonctions  du  Systeme  Nerveux," 
2dEdit.  1845. 

3  "Exper.  de  effect,  laosion.  in  partibus  Encephali,"  Berol.,  1826. 

4  "Lec,ons  sur  les  Fonctions  du  Systeme  Nerveux,"  Paris,  1839. 
6  "Traite  de  Physiologic,"  torn.  ii.  partie  2. 


SENSORY   GANGLIA. — CONSENSUAL  ACTIONS.  707 

Birds  and  Mammals,  may  survive  for  many  weeks  or  months  (if  their  physical 
wants  be  duly  supplied)  after  the  removal  of  the  entire  Cerebrum.  It  is  diffi- 
cult to  substantiate  the  existence  in  them  of  actual  sensation ;  but  some  of 
their  movements  appear  to  be  of  a  higher  kind  than  those  resulting  from  mere 
excito-motor  action.  One  of  the  most  remarkable  phenomena  exhibited  by  such 
a  being  is  the  power  of  maintaining  its  equilibrium,  which  could  scarcely  exist 
without  consciousness.  If  it  be  laid  upon  the  back,  it  rises  again  ;  if  pushed, 
it  walks.  If  a  Bird  thus  mutilated  be  thrown  into  the  air,  it  flies ;  if  a  Frog 
be  touched,  it  leaps.  It  swallows  food  and  liquid,  when  they  are  placed  in  its 
mouth;  and  the  digestive  operations,  the  acts  of  excretion,  &c.,  take  place  as 
usual.  In  the  case  of  a  Pigeon  experimented  on  by  Malacorps,  which  is  recorded 
by  Magendie,  there  appears  sufficient  proof  of  the  persistence  of  a  certain 
amount  of  sensation.  Although  the  animal  was  not  affected  by  a  strong  light 
suddenly  made  to  fall  upon  its  eyes,  it  was  accustomed,  when  confined  in  a  dark- 
ened or  partially  illuminated  room,  to  seek  out  the  light  parts  ;  and  it  avoided 
objects  that  lay  in  its  way.  In  the  same  manner,  it  did  not  seem  to  be  affected 
by  sudden  noises ;  but  at  night,  when  it  slept,  with  closed  eyes  and  its  head 
under  its  wing,  it  would  raise  its  head  in  a  remarkable  manner,  and  open  its 
eyes,  on  the  slightest  noise;  speedily  relapsing  into  a  state  of  complete  uncon- 
sciousness. Its  principal  occupation  was  to  prune  its  feathers  and  scratch  it- 
self. And  Longet  mentions  that  a  Pigeon  from  which  he  had  removed  the  en- 
tire Cerebrum  gave  many  indications  of  consciousness  of  light;  not  only  the 
pupil  contracting,  but  the  lids  closing,  when  a  strong  light  was  suddenly  made 
to  fall  upon  the  eye,  the  animal  having  been  previously  kept  in  darkness ;  and 
when  a  lighted  candle  was  made  to  move  in  a  circle  before  it,  the  animal  executed 
a  corresponding  movement  with  its  head.1 — The  condition  of  such  beings  seems 
to  resemble  that  of  a  Man,  who  is  in  a  slumber  sufficiently  deep  to  lose  all 
distinct  perception  of  external  objects,  but  who  is  yet  conscious  of  sensations,  as 
appears  from  the  movements  occasioned  by  light  or  by  sounds,  or  from  those 
which  he  executes  to  withdraw  the  body  from  an  uneasy  position  (§  787). 

735.  The  results  of  other  Experiments  made  upon  the  Sensory  ganglia  them- 
selves, and  upon  the  organs  from  which  they  derive  their  impressions,  confirm 
this  view ;  by  showing  that  the  ordinary  movements  are  seriously  perturbed,  and 
that  in  some  instances  a  new  set  of  automatic  movements  is  induced,  when  the 
ordinary  relations  between  the  sensory  and  motor  apparatus  are  disarranged. 
Among  the  ganglia  of  special  sensation,  the  functions  of  the  Optic  Lobes,  or 
Corpora  Quadrigemina,  have  been  chiefly  examined  experimentally.  The  re- 
searches of  Flourens  and  Hertwig  have  shown  that  their  connection  with  the 
visual  function,  which  might  be  inferred  from  their  anatomical  relations,  is  thus 
substantiated.  The  partial  loss  of  the  ganglion  on  one  side  produces  partial 
loss  of  power  and  temporary  blindness  on  the  opposite  side  of  the  body,  without 
necessarily  destroying  the  mobility  of  the  pupil ;  but  the  removal  of  a  larger 
portion  or  complete  extirpation  of  it,  occasions  permanent  blindness  and  immo- 
bility of  the  pupil,  with  temporary  muscular  weakness  on  the  opposite  side. 
This  temporary  disorder  of  the  muscular  system  sometimes  manifests  itself  (as 
already  stated)  in  a  tendency  to  move  on  the  axis,  as  if  the  animal  were  giddy. 
No  disturbance  of  consciousness  appears  to  be  produced ;  and  Hertwig  states 
that  he  never  witnessed  the  convulsions  which  Flourens  mentions  as  a  conse- 
quence of  the  operation,  and  which  were  probably  occasioned  by  his  incision 
having  been  carried  too  deeply.  As  Longet  has  justly  remarked,  it  is  difficult, 

i  It  must  not  be  forgotten  that,  in  such  experiments,  the  severity  of  the  operation  will 
of  itself  occasion  a  suspension  or  disturbance  of  the  functions  of  parts  that  remain ;  so 
that  the  loss  of  a  power  must  not  be  at  once  inferred  from  the  absence  of  its  manifesta- 
tions. But  the  persistence  of  a  power,  after  the  removal  of  a  particular  organ,  is  a  clear 
proof  that  it  cannot  be  the  peculiar  attribute  of  that  organ. 


708  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

if  not  impossible,  to  remove  one  or  both  of  these  ganglionic  masses,  without 
doing  such  an  injury  to  the  Crura  Cerebri  on  which  they  repose,  as  shall  in 
great  degree  account  for  such  disturbed  movements  (§  738).  Irritation  of  one 
of  the  Tubercula  Quadrigemina  has  been  observed,  both  by  Flourens  and  Longet, 
to  produce  contraction  of  the  pupils  of  both  eyes. — These  results  of  experiment 
are  partly  confirmed  by  Pathological  phenomena  in  Man  ;  for  there  are  many 
instances  on  record  in  which  blindness  has  been  one  of  the  consequences  of 
diseased  alterations  in  one  or  both  tubercles  ;  and  in  some  of  the  cases  in  which 
the  lesion  extended  to  parts  seated  beneath  the  tubercles,  disturbed  movements 
were  observed. — The  subservience  of  these  bodies  to  the  exercise  of  the  visual 
sense  appears,  on  the  whole,  to  be  the  point  best  established  in  regard  to  their 
functions ;  and  considering  the  degree  in  which  this  sense  is  concerned  in  the 
regulation  of  the  general  movements  of  the  body,  it  is  not  surprising  that 
lesions  of  its  centre  should  occasion  a  perversion  of  these  movements.  This 
appears  the  more  probable  from  the  fact  that,  in  animals  whose  Sensory  ganglia 
bear  so  large  a  proportion  to  the  whole  Encephalon,  that  we  must  look  upon 
them  as  the  principal  centres  of  motor  activity,  instead  of  being  chiefly  concerned 
(as  in  Man)  in  the  mere  guidance  of  movements  whose  origin  is  Cerebral, 
lesions  of  the  organ  of  sense,  from  which  the  impressions  that  excite  the  sen- 
sori-motor  impulses  are  derived,  produce  a  corresponding  disturbance.  Thus 
Flourens  found  that  a  vertiginous  movement  may  be  induced  in  Pigeons  by 
simply  blinding  one  eye ;  and  Longet  produced  the  same  effect  by  evacuating 
the  humors  of  the  eye. 

736.  It  is  probably  on  the  same  principle  that  we  are  to  account  for  the  re- 
markable results  obtained  by  Flourens  (Op.  cit.)  from  section  of  the  portion  of  the 
Auditory  nerve  proceeding  to  the  Semicircular  canals.    Section  of  the  horizontal 
semicircular  canal  in  Pigeons,  on  both  sides,  induces  a  rapid,  jerking,  horizontal 
movement  of  the  head  from  side  to  side ;  and  a  tendency  to  turn  to  one  side, 
which  manifests  itself  whenever  the  animal  attempts  to  walk  forwards.     Section 
of  a  vertical  canal,  whether  the  superior  or  inferior,  of  both  sides,  is  followed  by 
a  violent  vertical  movement  of  the  head.     And  section  of  the  horizontal  and 
vertical  canals,  at  the  same  time,  causes  horizontal  and  vertical  movements. 
Section  of  either  canal  on  one  side  only  is  followed  by  the  same  effect  as  when 
the  canal  is  divided  on  both  sides;  but  this  is  inferior  in  intensity.     The  move- 
ments continue  to  be  performed  during  several  months.     In  Rabbits,  section  of 
the  horizontal  canal  is  followed  by  the  same  movements  as  those  exhibited  by 
Pigeons ;  and  they  are  even  more  constant,  though  less  violent.     Section  of  the 
anterior  vertical  canal  causes  the  animal  to  make  continued  forward  "  somersets;" 
whilst  section  of  the  posterior   vertical   canal  occasions   continual   backward 
"  somersets."     The  movements  cease  when  the  animal  is  in  repose ;  and  they 
recommence  when  it  begins  to  move,  increasing  in  violence  as  its  motion  is  more 
rapid. — These  curious  results  are  supposed  by  M.  Flourens  to  indicate  that  the 
nerve  supplying  the  semicircular  canals  does  not  minister  to  the  sense  of  hear- 
ing, but  to  the  direction  of  the  movements  of  the  animal;  but  they  are  fully  ex- 
plained upon  the  supposition  that  the  normal  function  of  the  semicircular  canals 
is  to  indicate  to  the  aninufl  the  direction  of  sounds,  and  that  its  movements  are 
partly  determined  by  these ;  so  that  a  destruction  of  one  or  other  of  them  will 
produce  an  irregularity  of  movement  (resulting,  as  it  would  seem,  from  a  sort 
of  giddiness  on  the  part  of  the  animal),  just  as  when  one  of  the  eyes  of  a  bird 
is  covered  or  destroyed,  as  in  the  experiments  previously  cited. 

737.  The  numerous  Experiments  which  have  been  made  for  the  purpose  of 
determining  the  functions  of  the  Thalami  Optici  and  Corpora  Striata,  have  not 
yielded  any  very  satisfactory  results ;  and  this  on  account  of  the  impossibility  of 
completely  isolating  them  in  such  a  manner  as  to  limit  the  operation  (whether 
this  be  section,  removal,  or  irritation)  to  them  alone.     Thus  it  is  impossible  to 


SENSORY   GANGLIA.  —  CONSENSUAL   ACTIONS.  709 

i 

remove  them,  either  separately  or  conjointly,  without  first  removing  the  Cerebral 
Hemispheres;  and  the  Thalami  cannot  be  entirely  removed,  without  dividing  the 
stratum  of  fibres  which  passes  through  their  deeper  portion  in  their  passage  to 
the  Corpora  Striata.  The  evidence  afforded  by  Pathology,  too,  is  far  from  being 
self-consistent;  and  this,  it  may  be  surmised,  from  the  circumstance  that  the 
effects  of  morbid  changes  (particularly  of  sanguineous  effusions)  in  any  part  of 
the  Encephalon  extend  themselves  to  other  parts  than  those  in  which  the  ob- 
vious lesions  are  found;  as  is  abundantly  proved  by  the  great  variety  of  pheno- 
mena which  present  themselves  as  the  results  of  lesions  apparently  similar,  and 
the  similarity  of  the  phenomena  that  are  frequently  consequent  upon  lesions  of  very 
different  parts. — The  Thalami  Optici  have  not  that  relation  to  the  visual  sense  which 
their  designation  would  imply ;  for  (according  to  the  affirmation  of  Longet)  they 
may  be  completely  destroyed  in  Mammals  and  Birds,  without  destruction  of 
sight  or  loss  of  the  activity  of  the  pupil ;  and  irritation  of  one  or  both  of  them 
produces  no  contraction  of  the  pupil.  It  seems  probable,  therefore,  that  the 
loss  of  sight,  with  dilatation  and  immobility  of  the  pupil,  which  is  frequently 
observed  in  cases  of  apoplectic  effusion  into  the  substance  of  the  Thalami,  is 
really  due  to  the  compression  of  the  Optic  nerves  which  lie  beneath  them.  These 
bodies  appear,  however,  to  possess  a  very  decided  influence  on  the  power  of 
voluntary  movement ;  for,  although  an  animal  maintains  its  balance,  and  can  be 
made  to  move  onwards,  after  the  removal  of  the  Cerebral  Hemispheres,  and 
even  after  the  removal  of  the  Corpora  Striata,  yet  if  either  of  the  Thalami  Optici 
be  removed,  the  sensibility  and  power  of  voluntary  movement  are  destroyed  on 
the  opposite  side  of  the  body,  and  the  animal  consequently  falls  over  to  that 
side  (Longet).  If,  instead  of  the  entire  removal  of  one  of  the  Thalami,  an  in- 
cision be  made  in  it  without  the  previous  removal  of  the  Cerebrum,  the  animal 
keeps  turning  to  one  side  in  a  circular  manner  (evolution  du  maneye)  :  according 
to  Longet  and  Lafargue,  this  movement  is  directed  in  the  rabbit  towards  the  op- 
posite side ;  whilst  Flourens  states  that  in  the  frog  its  direction  is  towards  the 
injured  side ;  and  according  to  Schiff 1  the  destruction  of  the  three  anterior 
fourths  of  this  organ  in  the  rabbit  determines  this  movement  towards  the  injured 
side,  whilst  that  of  the  posterior  fourth  determines  the  movement  towards  the 
opposite  side.  No  mechanical  irritation  of  the  Thalami  produces  either  signs 
of  pain  or  muscular  movement ;  and  this  fact  might  at  first  appear  to  negative 
the  doctrine  that  these  organs  are  the  ganglia  of  common  sensation.  But  it 
must  be  borne  in  mind  that  the  production  of  pain  by  mechanical  injuries  is  by 
no  means  a  universal  phenomenon  in  the  case  of  the  nerve-trunks  which  min- 
ister to  sensation,  the  olfactive,  optic,  and  auditory  nerves  being  exempted ;  and 
it  need  occasion  still  less  surprise,  therefore,  that  a  nervous  centre  should  be 
destitute  of  this  kind  of  impressibility. — The  effects  of  lesions  of  the  Corpora 
Striata  are  less  distinctly  marked.  It  was  affirmed  by  Magendie  that  there 
exists  in  them  a  motor  power,  which  excites  backward  movement,  and  that  a 
corresponding  power  of  exciting  forward  movement  exists  in  the  Cerebellum; 
and  these  two  powers  ordinarily  balance  each  other ;  but  that,  if  either  organ 
be  removed,  the  power  of  the  other  will  occasion  a  continual  automatic  move- 
ment, the  removal  of  the  Corpora  Striata  causing  an  irresistible  tendency  to 
forward  progression,  whilst  the  division  of  the  peduncles  of  the  Cerebellum 
(according  to  him)  occasions  the  reverse  movement.  These  assertions,  however, 
have  not  been  confirmed  by  other  experimenters.  According  to  Longet  (Op.  cit.), 
Schiff,3  and  Lafargue,3  the  results  of  removal  of  the  Corpora  Striata  with  the 
anterior  part  of  the  Cerebral  hemispheres  are  for  the  most  part  negative ;  for 

1  Roser's  und  "VVunderlich's  "Archiv.  fur  Physiol.,  Heilkunde,"  1846,  §  667. 

2  "De  vi  motoria  baseos  encephali,"  Bockenhemii,  1845. 

3  "Essai  sur  la  valeur  des  localisations  encephaliques,"  &c.,  These  inaug.,  Paris,  1838. 


710  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

the  animal  usually  remains  in  a  state  of  profound  stupor,  although  still  retaining 
the  erect  position ;  and  it  is  only  when  irritated  by  pinching  or  pricking,  that  it 
will  execute  any  rapid  movements.  No  mechanical  irritation  of  the  Corpora 
Striata  produces  either  signs  of  pain  or  muscular  movement. — No  distinct  evi- 
dence regarding  the  special  functions  of  either  of  these  ganglionic  masses  can  be 
gained  from  Pathological  phenomena.  So  far  as  is  yet  known,  extensive  disease 
of  either  the  Thalamus  Opticus  or  the  Corpus  Striatum  of  one  side  produces 
hemiplegia,  or  paralysis  both  of  sensation  and  motion,  on  the  opposite  side. 
The  same  result  very  commonly  follows  an  apoplectic  effusion  into  the  substance 
of  either;  and  although  it  has  been  maintained  that,  when  the  lesion  is  limited 
to  the  Corpus  Striatum,  the  posterior  member  is  peculiarly  or  alone  affected,  and 
that  lesion  of  the  Thalamus  Opticus  alone  has  a  special  tendency  to  occasion 
paralysis  of  the  anterior  member,  yet  the  careful  analysis  which  has  been  made 
by  Andral1  into  the  pathological  phenomena  afforded  by  seventy-five  cases  of 
paralysis  in  which  the  apoplectic  effusion  was  limited  to  one  or  other  of  these 
bodies,  does  not  afford  the  least  countenance  to  any  such  doctrine.  And  it  is 
affirmed  by  Longet,  that  injury  or  removal  of  the  Corpus  Striatum  of  one  side 
did  not,  in  his  experiments,  affect  the  posterior  more  than  the  anterior  limb ; 
nor  could  he  detect  any  difference  in  the  condition  of  these  limbs  after  the  re- 
moval of  the  Thalamus. 

738.  When  the  fibrous  tracts  which  connect  these  ganglionic  masses  with  the 
Medulla  Oblongata,  and  which  are  commonly  (but  erroneously)  designated  as 
the  Orura  Cerebri,  are  completely  divided,  the  result,  as  might  be  anticipated, 
is  the  annihilation  of  sensibility  and  of  the  power  of  voluntary  movement  in  the 
body  generally.3  When,  however,  the  Crura  Cerebri  of  a  rabbit  are  not  com- 
pletely divided,  but  one  of  them  is  partially  cut  through,  a  little  in  front  of  the 
Pons  Varolii,  the  animal  is  said  by  Longet  and  Schiff  to  exhibit  a  constant 
tendency  to  turn  towards  the  side  opposite  to  that  of  the  lesion,  so  that  it  per- 
forms the  circular  evolution  du  maneye  ;  the  diameter  of  its  circle  of  movement 
being  smaller,  in  proportion  as  the  incision  approaches  the  edge  of  the  Pons. 
But  if  one  of  the  Crura  be  completely  divided,  the  animal  then  falls  over  on 
the  opposite  side ;  the  limbs  of  that  side  being  paralyzed  to  the  influence  of  the 
Encephalic  centres,  though  they  may  be  still  caused  to  exhibit  reflex  motions. 
Hence  it  appears  that  the  circular  movements  which  are  performed  after  incom- 
plete lesions  of  the  Crus  Cerebri  and  Thalamus  Opticus  of  either  side,  are  due 
to  the  weakening  of  the  sensori-motor  apparatus  of  the  opposite  side,  whereby 
the  balance  of  the  muscular  actions  of  the  two  sides  is  destroyed.  Nearly  the 
same  results  have  been  obtained  on  this  point  by  Longet,  Lafargue,  and  Schiff. 
— Considerable  importance  is  attached  by  some  Physiologists  to  the  part  of  the 
Encephalon  known  as  the  Tuber  Annulare,  to  which  the  name  of  Mesocephale 
has  also  been  given.  This  is  not  altogether  synonymous  with  the  Pons  Varolii, 
as  some  Anatomists  have  represented  it;  for,  while  the  latter  consists  of  trans- 
verse fibres,  which  form  the  commissure  between  the  hemispheres  of  the  Cere- 
bellum, surrounding  and  passing  between  the  longitudinal  fibres  of  the  Sensory 
and  Motor  tracts  which  constitute  the  Crura  Cerebri,  the  Tuber  Annulare  (which 
exists  in  animals  whose  Cerebellum  has  no  hemispheres)  is  a  projection  from 
the  surface  of  the  proper  Medulla  Oblongata,  containing  a  considerable  nucleus 
of  vesicular  matter.  The  experiments  of  Longet  have  led  him  to  the  conclusion 

1  "Clinique  Medicale,"  torn.  ii.  p.  664,  et  seq. 

2  It  is  considered  by  Longet  that  these  functions  are  not  completely  destroyed,  because 
the  animals  on  whom  this  operation  has  been  performed  still  retain  some  power  of  move- 
ment, and  respond  by  cries  to  impressions  that  ordinarily  produce  pain.     There  is  no  proof, 
however,  that  such  actions  are  other  than  "excito-motor;"  they  certainly  cannot  in  them- 
selves be  admitted  as  proving  the  persistence  of  consciousness  in  the  lower  segment  of  the 
Cerebro-Spinal  axis. 


INJURIES   OF   THE   NERVOUS   SYSTEM.  711 

that  this  ganglionic  mass  is  an  independent  centre  of  sensation  and  of  motor 
power ;  but  they  do  not  afford  any  clear  information  as  to  its  special  attributes. 
He  states,  however,  that  convulsive  movements  are  excited  by  irritating  it,  and 
especially  by  the  transmission  of  an  electric  current  through  its  substance. 
These  movements,  however,  according  to  the  testimony  of  Dr.  Todd,  appear  to 
be  of  a  different  character  from  those  which  are  excited  by  the  application  of 
the  same  stimulus  to  the  Spinal  Cord  and  Medulla  Oblongata;  for  he  states 
that,  whilst  the  convulsions  excited  by  the  transmission  of  the  current  of  the 
magneto-electric  machine  through  the  parts  just  named  are  tetanic,  the  muscles 
being  thrown  into  a  state  of  fixed  contraction — those  which  ensue  when  the 
current  is  transmitted  through  the  region  of  the  Mesocephale  and  Corpora 
Quadri gemma  are  epileptic,  being  combined  movements  of  alternate  contraction 
and  relaxation,  flexion  and  extension,  affecting  the  muscles  of  all  the  limbs,  of 
the  trunk,  and  of  the  eyes,  which  roll  about  just  as  in  epilepsy.1 

[Dr.  Brown-Sequard,  whose  experimental  researches  have  been  frequently 
quoted,  has  published  the  following  resume  of  the  phenomena  produced  by  in- 
juries of  the  nervous  system.3 

Pourfour  du  Petit  and  Mehee  de  la  Touche  were  the  first  experimenters  who 
witnessed  turning  produced  by  an  injury  of  the  nervous  centres.  But  the  first 
valuable  researches  on  this  phenomenon  were  made  by  Magendie  and  Flourens. 

The  parts  of  the  cerebro-spinal  centre  which  may  be  injured  without  produc- 
ing turning,  are :  the  cerebral  hemispheres,  the  cerebellum,  the  corpora  striata, 
the  corpus  callosum,  the  spinal  marrow,  and  the  olfactive  and  optic  nerves.3  In- 
juries of  all  the  other  parts  of  the  cerebro-spinal  centres  may  produce  turning 
or  rolling. 

These  circulatory  or  rotatory  movements  take  place  sometimes  on  the  same 
side  of  the  body,  and  sometimes  on  the  side  opposite  to  that  portion  of  the  en- 
cephalon  which  has  been  injured. 

A  puncture  of  one  of  the  following  parts  produces  turning  or  rolling  on  the 
injured  side  : — 

1.  The  anterior  extremity  of  the  thalami  optici,  according  to  Schiff. 

2.  The  crura  cerebri,  according  to  Magendie. 

3.  The  bi-,  or  quadrigeminal  tubercles,  according  to  Flourens. 

4.  The  pons  Varolii. 

5.  The  posterior  part  of  the  processus  cerebelli  ad  pontem. 

6.  The  auditive  nerve,  according  to  Brown-Sequard. 

7.  The  medulla  oblongata  at  the  point  of  insertion  of  the  facial  nerve,  accord- 
ing to  the  experiments  of  Brown-Sequard,  in  common  with  Dr.  Martin-Magron. 

8.  The  medulla  oblongata  outside  of  the  anterior  pyramids,  according  to 
Magendie. 

9.  A  great  part  of  the  posterior  face  of  the  medulla  oblongata,  according  to 
Brown-Sequard. 

The  parts  of  the  encephalon  which  produce  turning  or  rolling  on  the  opposite 
side  are  : — 

1 .  The  posterior  extremity  of  the  thalami  optici,  according  to  Schiff. 

2.  The  crura  cerebri,  according  to  Lafargue. 

3.  The  anterior  part  of  the  processus  cerebelli  ad  pontem. 

4.  A  small  part  of  the  medulla  oblongata  before  the  nib  of  the  calamus  scrip- 

1  Lumleian  Lectures  "On  the  Pathology  and  Treatment  of  Convulsive  Diseases,"  in 
"Medical  Gazette,"  May  11,  1849. 

2  ["Phil.  Med.  Examiner,"  August  1852.] 

3  [The  three  nerves  of  the  superior  senses,  the  olfactive,  the  optic,  and  the  auditive,  are 
considered,  by  the  author  of  the  article  here  quoted,  as  a  part  of  the  nervous  centres. — ED.] 


712  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

torius  and  behind  the  corpora  olivaria,  according  to  Brown-Sequard's  experi- 
ments in  common  with  Dr.  Martin-Magron. 

Some  of  these  two  series  of  parts  ordinarily  produce  turning,  and  others 
rolling.  But  these  two  kinds  of  movements  can  be  produced  by  the  puncture 
of  a  single  part  of  the  encephalon.  Rolling  is  nothing  but  the  exaggeration  of 
turning ;  thus,  after  a  puncture  of  the  medulla  oblongata,  the  animal  at  first 
rolls,  and  after  some  instants,  instead  of  rolling,  it  turns.  If,  when  it  is 
turning,  a  slight  puncture  is  made  anew,  close  to  the  first,  then  the  animal 
rolls. 

1.  Turning  and  Rolling  caused  by  tearing  the  Facial  Nerve. — Dr.  Martin- 
Magron  and  Dr.  Brown-Sequard  have  discovered  that,  if  the  facial  nerve  of  a 
rabbit  or  a  guinea-pig  be  exposed  at  its  exit  from  the  stylo-mastoid  foramen,  and 
then  drawn  away  from  the  cranium,  so  as  to  tear  it  asunder  near  its  origin, 
the  animal  begins  in  about  five  minutes  to  turn  itself  round  and  round,  the  move- 
ment being  from  left  to  right  when  the  nerve  has  been  thus  torn  on  the  left 
side,  and  from  right  to  left  when  it  has  been  torn  on  the  right  side.     This  ro- 
tation is  generally  preceded  by  convulsive  movements  of  the  eyes,  of  the  jaws, 
and  of  the  head  upon  the  trunk  :  and  the  body  is  then  bent  (as  in  pleurostho- 
tonos)  towards  the  injured  side,  by  the  contraction  of    all   the   longitudinal 
muscles  of  that  side,  the  power  of  which  is  such  as  to  resist  considerable  force 
applied  to  extend  them.     The  movement  at  first  takes  place  in  a  small  circle; 
but  the  circle  generally  enlarges  more  and  more,  until  at  last,  after  twenty 
or  thirty  minutes,  the  animal  walks  in  a  straight  line.     There  is  no  paralysis 
of  any  muscles,  save  the  facial.     The  effect  is  not  produced,  unless  the  nerve 
be  torn  close  to  its  origin. 

When  the  nerve  on  the  other  side  also  is  torn,  even  after  a  long  interval, 
instead  of  the  tendency  to  turn  to  one  side,  there  is,  at  first,  a  rolling  of  the 
body  on  its  longitudinal  axis,  which  takes  place  towards  the  side  last  operated 
on.  After  this  has  continued,  however,  for  twenty  minutes  or  more,  the  animal 
recovers  its  feet,  and  begins  to  turn,  as  after  the  first  operation,  but  towards  the 
other  side.  This  movement  soon  ceases. 

Dr.  Martin-Magron  and  the  author  think  that  the  cause  of  these  phenomena 
does  not  exist  in  the  facial  nerve  itself,  but  in  the  part  of  the  medulla  oblongata 
from  which  this  nerve  originates.1 

2.  Turning  and  Rolling  produced  by  an  Injury  to  the  Medulla  Oblongata. — 
M.  Magendie3  says  :  "  Having  raised  up  the  cerebellum,  I  make  a  section  per- 
pendicularly to  the  surface  of  the  fourth  ventricle,  and  at  three  or  four  milli- 
metres from  the  median  line.    If  I  cut  on  the  right,  the  animal  will  turn  on  the 
right  side ;  if  I  cut  on  the  left,  it  will  turn  on  the  left  side." 

If  we  suppose  a  plane  cutting  the  medulla  oblongata  transversely  at  the  dis- 
tance of  nearly  two  lines  before  the  nib  of  the  calamus  scriptorius,  the  posterior 
face  of  the  medulla  oblongata  will  be  divided  into  two  parts :  one  before  that 
plane  which  the  author  calls  superior,  and  the  other  behind,  or  inferior. 

Now,  every  puncture  on  that  superior  part  produces  turning  or  rolling  on  the 
side  which  has  been  punctured.  The  slightest  puncture  on  the  processus  cere- 
belli  ad  medullam  oblongatam  will  produce  a  violent  and  very  rapid  rolling. 
As  long  as  the  anim'al  lives  after  the  operation,  it  rolls  or  it  turns  every  time  it 
tries  to  walk. 

When  (as  Dr.  Martin-Magron  and  the  author  have  discovered)  a  deep  section 
is  made  on  the  inferior  part  of  the  posterior  face  of  the  medulla  oblongata,  before 
the  nib  of  the  calamus  scriptorius,  turning  is  produced  on  the  side  of  the  body 


1  [S« 

2L" 


See  "Gaz.  Med.  de  Paris,"  1849,  t.  iv.  p.  879.] 
Precis  Elem.  de  Physiol.,"  Paris,  1836,  t.  i.  p.  414.] 


ON  THE  CAUSES  OF  TURNING  AND  ROLLING.         713 

opposite  to  the  punctured  side  of  the  medulla.  A  rabbit,  which  lived  thirteen 
days  after  the  operation,  had  still  the  circulatory  movement  a  few  hours  before 
dying  j  although  sometimes  the  animal  could  walk  nearly  straight  for  a  few 
seconds. 

3.  Turning  produced  by  a  Puncture  or  a  Section  of  the  Acoustic  Nerve. — 
Flourens  has  discovered  that,  after   the   section  of  the    semicircular   canals, 
turning  sometimes  takes  place. 

The  author  has  found  all  the  facts  detailed  in  relation  to  this  subject.  It 
was  interesting  to  know  if  a  puncture  or  the  section  of  the  auditive  nerve  would 
produce  turning.  As  it  was  impossible  to  operate  on  that  nerve  in  mammals, 
he  experimented  on  frogs.  In  these  amphibia,  it  is  easy  to  find  the  nerve  and 
to  act  upon  it.  He  found  that,  after  a  puncture  or  a  section  on  the  trunk  of 
the  nerve,  the  animal  begins  instantly  to  turn.  As  long  as  the  frogs  live,  after 
a  puncture  of  the  acoustic  nerve,  they  turn;  but  the  circle  of  turning  is  much 
smaller  a  short  time  after  the  operation  than  afterwards.  He  has  kept  such 
frogs  alive  for  months. 

4.  On  a  New  Mode  of  Turning. — The  same  experimenter  has  discovered  a 
mode  of  turning  which  has  some  of  the  characters  of  both  turning  and  rolling. 

In  the  circulatory  movement  called  turning  (mouvement  de  manege},  the  body 
of  the  animal  is  bent  on  one  of  the  lateral  sides.  It  has  the  shape  of  an  arch, 
and  this  arch  is  generally  a  part  of  the  circumference  described  by  the  animal 
when  turning.  The  smaller  the  radius  of  that  arch,  the  smaller  is  the  circle  of 
turning. 

In  the  new  mode  of  turning,  the  body  of  the  animal  is  not  bent,  and  when  it 
walks  it  moves  laterally,  instead  of  going  forwards.  In  turning,  it  describes  a 
circle,  but  the  longitudinal  axis  of  its  body,  instead  of  being  then  a  part  of  the 
circumference,  is  a  part  of  a  radius,  so  that  its  head  is  at  the  circumference,  and 
its  tail  towards  the  centre  of  the  described  circle. 

This  mode  of  turning  has  been  performed  by  animals  on  whom  the  quadrigemi- 
nal  tubercles  and  the  pons  Varolii,  on  one  side,  had  been  punctured  by  a  pin. 
One  of  the  eyes  was  convulsed ;  the  other  was  in  its  normal  condition.  The 
convulsed  eye  was  the  right  one,  and  the  tubercles  punctured  were  those  of  the 
left  side. 

5.  On  the  Causes  of  Turning  and  Rolling. — 1.  As  the  slightest  puncture  of 
certain  parts  of  the  encephalon  is  sufficient  to  produce  turning  or  rolling,  it  is 
evident  that  those  rotating  movements  do  not  exist  in  consequence  of  an  hemi- 
plegia,  as  Lafargue,  Longet,  and  Schiff  believe  they  do.     Another  reason  is  that 
every  degree  of  hemiplegia  exists  in  man  without  being  accompanied  by  turning 
or  rolling.     Besides,  these  phenomena  have  been  observed  in  persons  who  had 
no  paralysis  at  all. 

2.  The  theories  of  Magendie  and  Flourens  are  also  opposed  by  the  fact  that 
a  slight  puncture  is  sufficient  to  produce  turning  or  rolling. 

3.  As  to  the  theory  of  Henle,  which  is  based  upon  the  existence  of  convul- 
sions in  the  eye,  producing  a  kind  of  vertigo,  it  has  against  it  the  facts  that,  on 
one  side,  convulsions  may  exist  in  the  eyes  without  any  other  disorder  in  the 
movements ;  and,  on  the  other  side,  sometimes  turning  or  rolling  exists  without 
any  convulsion  in  the  eyes.1 

Nevertheless,  in  many  cases,  the  vertigo  consequent  on  convulsions  of  the 
eyes  is  one  element  of  the  cause  of  turning.  And  in  certain  cases,  paralysis 
of  some  parts  of  the  body  may  facilitate  the  rotatory  movements.  But  their 
great  cause  is  the  existence  of  a  convulsive  contraction  in  some  of  the  muscles, 

1  [See  a  very  remarkable  case  observed  by  Dr.  Lebret,  in  "Comptes  Rendus  et  Me- 
moires  de  la  Soc.  Biologic,"  annee  1850,  Paris,  1851,  t.  ii.  p.  7.] 


714  OP   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

on  one  side  of  the  body.  These  convulsive  contractions  are  to  be  found  in 
every  case  of  circulatory  or  rotatory  movement.  As  to  the  cause  of  these 
contractions,  it  exists  in  the  irritation  produced  in  certain  parts  of  the  ence- 
phalon. — ED.] 

739.  Nerves  of  Special  Sense. — Having  thus  taken  a  general  survey  of  the 
information  supplied  by  Comparative  Anatomy,  Experiment,  and  Pathological 
phenomena,  in  regard  to  the  functions  of  this  division  of  the  Encephalon,  we 
shall  next  inquire  into  the  attributes  of  the  Nerves  of  which  they  are  obviously 
the  ganglionic  centres. — Through  the  First  pair,  or  Olfactory  nerves,  are  trans- 
mitted the  impressions  made  by  odorous  emanations  upon  the  surface  it  supplies ; 
and  it  is  not  susceptible  to  impressions  of  any  other  kind.     Anatomical  exami- 
nation of  the  distribution  of  this  nerve  proves  that  it  is  not  one  which  directly 
conveys  motor  influence  to  any  muscles,  since  all  its  branches  are  distributed 
to  the  membrane  lining  the  nasal  cavity;  and  experimental  inquiry  leads  to  the 
same  result,  for  no  irritation  of  the  peduncles  or  branches  excites  any  muscular 
movement.     Further,  no  irritation  of  any  part  of  this  nerve  excites  reflex  actions 
through  other  nerves.     Again,  it  is  not  a  nerve   of  common  sensation;  for 
animals  exhibit  no  sign  of  pain,  when  it  is  subjected  to  any  kind  of  irritation. 
Neither  the  division  of  the  nerve,  nor  the  destruction  of  the  olfactive  ganglia, 
seems  to  inconvenience  them  materially.     They  take  their  food,  move  with  their 
accustomed  agility,  and  exhibit  the  usual  appetites  of  their  kind.     The  "  com- 
mon" sensibility  of  the  parts  contained  in  the  olfactive  organ  is  in  no  degree 
impaired,  as  is  shown  by  the  effect  of  irritating  vapors ;  but  the  animals  are 
destitute  of  the  sense  of  smell,  as  is  shown  by  the  way  in  which  these  vapors 
affect  them.    At  first  they  appear  indifferent  to  their  presence,  and  then  suddenly 
and  vehemently  avoid  them,  as  soon  as  the  Schneiderian  membrane  becomes 
irritated.     Moreover,  if  two  dogs,  with  the  eyes  bandaged,  one  having  the  olfac- 
tory nerves  and  ganglia  sound,  and  the  other  having  had  them  destroyed,  are 
brought  into  the  neighborhood  of  the  dead  body  of  an  animal,  the  former  will 
examine  it  by  its  smell;  whilst  the  latter,  even  if  he  touches  it,  pays  no  attention 
to  it.     This  experiment  Valentin1  states  that  he  has  repeated  several  times,  and 
always  with  the  same  results.     Further,  common  observation  shows  that  sensi- 
bility to  irritants,  such  as  snuff,  and  acuteness  of  the  power  of  smell,  bear  no 
constant  proportion  to  one  another;  and  there  is  ample  pathological  evidence, 
that  the  want  of  this  sense  is  connected  with  some  morbid  condition  of  the 
olfactory  nerves  or  ganglia. — It  is  well  known  that  Magendie  has  maintained 
that  the  Fifth  pair  in  some  way  furnishes  conditions  requisite  for  the  enjoyment 
of  the  sense  of  smell;  asserting  that,  when  it  is  cut,  the  animal  is  deprived  of 
this.     But  his  experiments  were  made  with  irritating  vapors,  which  excite 
sternutation  or  other  violent  muscular  actions,  not  through  the  Olfactory  nerve, 
but  through  the  Fifth  pair;  and  the  experiments  of  Valentin,  just  related,  fully 
prove  that  the  animals  are  not  sensitive  to  odors,  strictly  so  called,  after  the 
Olfactory  nerve  has  been  divided.     It  is  highly  probable,  however,  that  the 
acuteness  of  the  true  sense  of  smell  may  be  diminished  by  section  of  the  Fifth 
pair;  since  the  Schneiderian  membrane  is  no  longer  duly  moistened  by  its 
proper  secretion ;  and,  when  dry,  it  is  not  so  susceptible  of  the  impressions  made 
by  those  minute  particles  of  odoriferous  substances,  to  which  the  excitement  of 
the  sensation  must  be  referred. 

740.  That  the  Second  pair,  or  Optic  nerves,  have  an  analogous  character, 
appears  alike  from  anatomical  and  experimental  evidence.     No  chemical  or  me- 
chanical stimulus  of  the  nerve  produces  direct  muscular  motion ;  nor  does  it  give 
rise,  so  far  as  can  be  ascertained,  to  indications  of  pain ;  whence  it  may  be  con- 

>  "De  Functionibus  Nervorum  Cerebralium,"  &c.,  Bernae,  1839. 


NERVES   OF   SPECIAL   SENSE. — OPTIC. 


715 


eluded  that  this  nerve   is  not  one  of  Fig-  190. 

common  sensation.  That  the  ordinary 
sensibility  of  the  eyeball  remains,  when 
the  functions  of  the  Optic  nerve  are 
completely  destroyed,  is  well  known ;  as 
is  also  the  fact  that  division  of  it  puts 
an  end  to  the  power  of  vision.  Valen- 
tin states  that,  although  the  Optic  nerve 
may,  like  other  nerves,  be  in  appearance 
completely  regenerated,  he  has  never 
been  able  to  obtain  any  evidence  that 
the  power  of  sight  has  been  in  the  least 
degree  recovered.  He  remarks  that  ani- 
mals suddenly  made  blind  exhibit  great 
mental  disturbance,  and  perform  many 
unaccustomed  movements  ;  and  that 
the  complete  absence  of  the  power  of 
vision  is  easily  ascertained.  Morbid 
changes  are  sometimes  observed  to  take 
place  in  eyes  whose  Optic  nerve  has 
been  divided;  but  these  are  by  no 
means  so  constant  or  so  extensive  as 
when  the  Fifth  pair  is  paralyzed ;  and 
they  may  not  improbably  be  attributed 
to  the  injury,  occasioned  by  the  opera- 
tion itself,  to  the  parts  within  the  orbit. 
741.  The  Optic  nerve,  though  an- 
alogous to  the  Olfactory  in  all  the 
points  hitherto  mentioned,  differs  from 
it  in  one  important  respect ; — that  it  has 
the  power  of  conveying  impressions 
which  excite  reflex  muscular  motions. 
This  is  especially  the  case  in  regard  to 

the  Iris,  the  ordinary  actions  of  which  are  regulated  by  the  degree  of  light  im- 
pinging on  the  retina.  When  the  Optic  nerve  is  divided,  a  contraction  of  the 
pupil  takes  place;  but  this  does  not  occur,  if  the  connection  of  this  nerve  with 
the  third  pair,  through  the  nervous  centres,  be  in  any  way  interrupted.  After 
such  division  (if  complete),  the  state  of  the  pupil  is  not  affected  by  variations 
in  the  degree  of  light  impinging  on  the  retina ;  except  in  particular  cases,  in 
which  it  is  influenced  through  other  channels.  Thus,  in  a  patient  suffering 
under  amaurosis  of  one  eye,  the  pupil  of  the  affected  eye  is  often  found  to  vary 
in  size,  in  accordance  with  that  of  the  other  eye ;  but  this  effect  is  produced  by 
the  action  of  light  on  the  retina  of  the  sound  eye,  which  produces  a  motor  change 
in  the  third  pair  on  both  sides.  Further,  as  already  shown  (§  724),  the  im- 
pression only  of  light  upon  the  retina  may  give  rise  to  contraction  of  the  pupil, 
by  reflex  action,  when  the  optic  nerve  is  itself  sound ;  whilst  no  sensations  are 
received  through  the  eye,  in  consequence  of  disease  in  the  sensorial  portion  of 
the  nervous  centres.  Although  the  contraction  of  the  pupil  is  effected  by  the 
influence  of  motor  fibres,  which  proceed  to  the  sphincter  of  the  Iris  from  the 
third  pair  of  nerves,  through  the  Ophthalmic  ganglion,  there  is  evidence  that  its 
dilatation  depends  rather  upon  the  influence  it  derived  frOrn  that  ganglion  itself, 
and  from  the  Sympathetic  system,  of  which  it  forms  part. — Some  have  attempt- 
ed to  show  that  the  actions  of  the  iris  are  in  a  slight  degree  voluntary,  because, 
by  an  effort  of  the  will,  they  could  occasion  contraction  of  the  pupil ;  but  this 
so-called  voluntary  contraction  is  always  connected  with  a  change  ;in  the  place 


A  view  of  the  2d  pair  or  optic,  and  the  origins  of 
seven  other  pairs.  1, 1.  Globe  of  the  eye;  >the  one 
on  the  left  hand  is  perfect,  but  that  on  the  right  has 
the  sclerotic  and  choroid  removed  to  show  the  retina. 
2.  The  chiasin  of  the  optic  nerves.  3.  The  corpora 
albicantia.  4.  The  infundibulum.  5.  The  Pons 
Varolii.  6.  The  medulla  oblongata.  The  figure  is 
on  the  right  corpus  pyramidale.  7.  The  3d  pair, 
motores  oculi.  8.  4th  pair,  pathetici.  9.  5th  pair, 
trigemini.  10.  6th  pair,  abducentes.  11.  7th  pair, 
auditory  and  facial.  12.  8th  pair,  pneumogastric, 
spinal  accessory,  and  glosso-pharyngeal.  13.  9th 
pair,  hypoglossal. 


716  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

of  the  eyeball  itself,  occasioned  by  an  action  of  some  of  its  muscles.  It  is 
principally  noticed  under  the  two  following  conditions :  1.  When  an  object 
is  brought  very  near  the  eye,  and  we  steadily  fix  our  attention  upon  it,  the  axes 
of  the  two  eyes  are  made  to  converge ;  and  if  this  convergence  be  carried  to  a 
considerable  extent,  so  that  the  pupils  of  both  eyes  are  sensibly  directed  towards 
the  inner  canthus,  a  contraction  of  the  pupil  takes  place.  The  final  cause  or 
purpose  of  this  contraction  is  very  evident.  "When  an  object  is  brought  near 
the  eye,  the  rays  proceeding  from  it  would  enter  the  pupil  (if  it  remained  of 
its  usual  size)  at  an  angle  of  divergence  so  much  greater  than  that  which  would 
allow  them  to  be  properly  refracted  to  a  focus,  that  indistinct  vision  would 
necessarily  result.  By  the  contraction  of  the  pupil,  however,  the  extreme  or 
most  divergent  rays  are  cut  off,  and  the  pencil  is  reduced  within  the  proper 
angle.  The  principle  is  precisely  the  same  as  that  on  which  the  optician  applies 
a  stop  behind  his  lenses,  which  reduces  their  aperture  in  proportion  to  the  short- 
ness of  their  focal  distance.  2.  Contraction  of  the  pupil  is  also  noticed,  when 
the  eyeball  is  performing  that  rotation  upwards  and  inwards,  which,  when  it 
occurs  along  with  violent  respiratory  actions,  or  during  sleep,  must  be  regarded 
as  involuntary.  (This  rotation  also  takes  place,  to  a  slight  degree,  when  the 
eyelid  is  depressed,  as  in  ordinary  winking;  and  it  is  obvious  that,  in  this 
manner,  the  surface  of  the  eye  is  more  effectually  swept  free  from  impurities 
which  may  have  gathered  upon  it,  than  it  would  be  by  the  downward  motion  of 
the  lid  alone.)  But  the  pupil  is  not  contracted,  when  the  eyeball  is  voluntarily 
rotated  upwards  and  inwards.  Besides  the  contractions  of  the  pupil,  another 
action  of  a  "  reflex"  character  is  produced  through  the  Optic  nerve — the  con- 
traction of  the  Orbicularis  muscle  under  the  influence  of  strong  light,  or  when 
a  foreign  body  is  suddenly  brought  near  the  eye.  But  this  cannot  be  produced 
without  a  consciousness  of  the  object;  in  fact,  it  is  a  movement  of  a  "  consen- 
sual" kind,  produced  by  the  painful  effect  of  light,  which  gives  rise  to  the 
condition  well  characterized  by  the  term  photophobia.  The  involuntary  charac- 
ter of  it  must  be  evident  to  every  one  who  has  been  engaged  in  the  treatment 
of  diseases  of  the  eyes;  and  the  effect  of  it  is  aided  by  a  similarly  involuntary 
movement  of  the  eyeball  itself,  which  is  rotated  upwards  and  inwards,  to  a 
greater  extent  than  the  Will  appears  able  to  effect. — Another  reflex  movement 
excited  through  the  visual  sense  is  that  of  Sneezing,  which  is  induced  in  many 
individuals  by  the  sudden  exposure  of  the  eyes  to  a  strong  light :  of  the  purely 
automatic  character  of  this  movement  there  can  be  no  question,  since  it  cannot 
be  imitated  voluntarily ;  and  that  it  is  not  excito-motor  is  proved  by  the  fact 
that  it  is  not  excited  unless  the  light  is  seen.1 

742.  There  is  a  further  peculiarity,  of  a  very  marked  kind,  attending  the 
course  of  the  Optic  nerves ;  this  is  the  crossing  or  decussation  which  they  under- 
go, more  or  less  completely,  whilst  proceeding  from  their  ganglia  to  the  eyes. 
n  some  of  the  lower  animals,  in  which  the  two  eyes  (from  their  lateral  position) 
have  entirely  different  spheres  of  vision,  the  decussation  is  complete ;  the  whole 
of  the  fibres  from  the  right  optic  ganglion  passing  into  the  left  eye,  and  vice 
versa.  This  is  the  case,  for  example,  with  most  of  the  Osseous  Fishes  (as  the 
cod,  halibut,  &c.)  ;  and  also,  in  great  part  at  least,  with  Birds.2  In  the  Human 
subject,  however,  and  in  animals  which,  like  him,  have  the  two  eyes  looking  in 
the  same  direction,  the  decussation  seems  less  complete ;  but  there  is  a  very 
remarkable  arrangement  of  the  fibres,  which  seems  destined  to  bring  the  two 
eyes  into  peculiarly  consentaneous  action.  The  posterior  border  of  the  Optic 
Chiasma  is  formed  exclusively  of  commissural  fibres,  which  pass  from  one  optic 

1  A  patient  was  for  some  time  in  the  London  Hospital,  in  whom  there  was  such  an  undue 
impressibility  of  the  retina  that  she  could  not  remain  in  even  a  moderate  light  without  a 
continual  repetition  of  the  act  of  Sneezing. 

2  See  Solly  on  "  The  Human  Brain,"  Am.  Ed. 


NERVES   OF   SPECIAL   SENSE.  —  OPTIC.  717 

ganglion  to  the  other,  without  entering  the  real  optic  nerve.  Again,  the 
anterior  border  of  the  Chiasma  is  composed  of  fibres,  which  seem,  in  like 
manner,  to  act  as  a  commissure  between 

the  two  retinae;  passing  from  one  to  Fig-  191. 

the  other,  without  any  connection  with 
the  optic  ganglia.  The  tract  which  lies 
between  the  two  borders,  and  occupies 
the  middle  of  the  Chiasma,  is  the  true 
Optic  Nerve;  and  in  this  it  would  ap- 
pear that  a  portion  of  the  fibres  decus- 
sates, whilst  another  portion  passes 
directly  from  each  Optic  ganglia  into 

the  Corresponding  eye.  The  fibres  which  Course  of  fibres  in  the  chiasma,  as  exhibited  by 
proceed  from  the  ganglia  to  the  retinse,  tearin&  off  the  superficial  bundles  from  a  specimen 

and  constitute  the  proper  Optic  Nerves,    ^afrdened  /'n  frit'  *  Anterio;  fifbres'  cfi°™">al 

,        ,.     .          .  f    f .    ,     "       .  '     between  the  two  retinae,    p.  Posterior  fibres,  corn- 

may  be  distinguished  into  an  internal    missural  between  the  thalamL   fl,  y    Diagram  of 

and  an  external  tract.  Of  these,  the  the  preceding. 
external  on  each  side  passes  directly  on- 
wards to  the  eye  of  that  side ;  whilst  the  internal  crosses  over  to  the  eye  of  the 
opposite  side.  The  distribution  of  these  two  sets  of  fibres  in  the  retina  of  each 
eye  respectively,  is  such  that,  according  to  Mr.  Mayo,  the  fibres  from  either 
optic  ganglion  will  be  distributed  to  its  own  side  of  both  eyes  j1  the  right  optic 
ganglion  being  thus  exclusively  connected  with  the  outer  part  of  the  retina  of 
the  right  eye,  and  with  the  inner  part  of  the  retina  of  the  left  eye ;  and  the  left 
optic  ganglion  being,  in  like  manner,  connected  exclusively  with  the  outer  side 
of  the  left  retina,  and  with  the  inner  side  of  the  right.  Now,  as  either  side  of 
the  eye  receives  the  images  of  objects  which  are  on  the  other  side  of  its  axis, 
it  follows,  if  this  account  of  their  distribution  be  correct,  that  in  Man,  as  in 
the  lower  animals,  each  ganglion  receives  the  sensations  of  objects  situated  on 
the  opposite  sides  of  the  body.  The  purpose  of  this  decussation  may  be,  to 
bring  the  visual  impressions,  which  are  so  important  in  directing  the  movements 
of  the  body,  into  proper  harmony  with  the  motor  apparatus ;  so  that,  the  de- 
cussation of  the  motor  fibres  in  the  pyramids  being  accompanied  by  a  decussa- 
tion of  the  optic  nerves,  the  same  effect  is  produced  as  if  neither  decussated — 
which  last  is  the  case  with  Invertebrated  animals  in  general. 

743.  The  functions  of  the  Auditory  nerve,  or  Portio  Mollis  of  the  7th,  are 
easily  determined,  by  anatomical  examination  of  its  distribution,  and  by  obser- 
vation of  pathological  phenomena,  to  be  analogous  to  those  of  the  two  preced- 
ing. Atrophy  or  lesion  of  the  trunk  destroys  the  sense  of  Hearing;  whilst 
irritation  of  it  produces  auditory  sensations,  but  does  not  occasion  pain.  From 
experiments  made  upon  the  nerve  before  it  leaves  the  cranial  cavity,  it  appears 
satisfactorily  ascertained  that  this  nerve  is  not  endowed  either  with  common 
sensibility,  or  with  the  power  of  directly  stimulating  muscular  movement. 
Nor  can  any  obvious  reflex  actions  be  executed  by  irritation  of  this  nerve; 
but  it  seems  nevertheless  by  no  means  improbable,  that  the  muscles  which 
regulate  the  tension  of  the  tympanum  are  called  into  action  by  impressions 
made  upon  it  and  reflected  through  the  auditory  ganglion,  in  the  same  manner 

1  This  arrangement  was  first  hypothetically  suggested  by  Dr.  Wollaston  ("Philos. 
Trans.,"  1824),  as  facilitating  the  explanation  of  some  of  the  phenomena  of  vision,  and 
more  particularly  single  vision  with  two  eyes.  We  shall  hereafter  see,  however,  that  the 
singleness  of  the  impression  resulting  from  the  formation  of  two  pictures  upon  our  retinas 
is  not  attributable  to  any  such  anatomical  arrangement,  their  combination  being  a  mental 
process,  and  the  fusion  of  two  dissimilar  pictures  being  requisite  to  enable  us  to  exercise 
one  of  the  highest  attributes  of  the  visual  sense,  the  perception  of  projection.  (See  CHAP. 
xv.  SECT.  5.) 


718 


Or  THE  FUNCTIONS  OP  THE  NERVOUS  SYSTEM. 


A  view  of  the  origin  and  distribution  of  the  Portio 
Mollis  of  the  Seventh  pair  or  Auditory  Nerve  :  1,  the 
medulla  oblongata ;  2,  the  pons  Varolii ;  3,  4,  the 
crura  cerebelli  of  the  right  side ;  5,  the  eighth  pair  of 
nerves  ;  6,  the  ninth  pair ;  7,  the  auditory  nerve  dis- 
tributed to  the  cochlea  and  labyrinth ;  8,  the  sixth 
pair  of  nerves ;  9,  the  portio  dura  of  the  seventh  pair  ; 
10,  the  fourth  pair;  11,  the  fifth  pair. 


Fig.  192.  as  the  diameter  of  the  pupil  is  regu- 

lated through  the  Optic  nerve.  In  the 
involuntary  start,  however,  which  is 
occasioned  by  a  loud  and  sudden  sound, 
we  have  an  example  of  a  consensual 
movement  excited  through  the  Audi- 
tory nerve,  which  is  evidently  analogous 
to  the  closure  of  the  eyes  to  a  strong 
light.  In  certain  morbidly  impressible 
states  of  the  nervous  system,  as  will  be 
shown  hereafter,  the  effect  of  sounds  on 
the  motor  apparatus  is  far  more  re- 
markable.— It  has  been  attempted  by 
Flourens  to  show  that  the  division  of 
the  Auditory  nerve,  which  proceeds  to 
the  Semicircular  canals,  has  functions 
altogether  different  from  that  portion 
which  supplies  the  Vestibule  and 
Cochlea.  This  inference,  however,  is 
grounded  only  upon  the  movements 
exhibited  by  animals  in  which  these 

nerves  are  irritated ;  which  movements  are  capable  of  a  different  explanation 

(§  736). 

744.  The  nerves  which  minister  to  the  sense  of  Taste  are  destitute  of  the 
peculiarities  which  distinguish    the  preceding;    being  no   other   than  certain 
branches  of   ordinary  afferent  nerves — the  Fifth  Pair  and  Glosso-pharyngeal 
(§  717) — the  peculiar  endowments  of  which  seem  to  depend  rather  upon  the 
structure  and  actions  of  the  papillae  at  their  peripheral  extremities  than  upon 
anything  special  in  their  own  characters ;  for,  as  in  the  case  of  the  ordinary 
nerves  of  "  common"  sensation,  mechanical  irritation  applied  to  them  calls  forth 
indications  of  pain. — From  the  observations  and  experiments  of  M.   Cl.  Ber- 
nard,1 it  appears  that  the  Facial  nerve  (portio  dura  of  the  7th)  supplies  some 
condition  requisite  for  the  sense  of  Taste,  through  the  branch  known  as  the 
Chorda  Tympani,  which  is  the  motor  nerve  of  the  Lingualis  muscle.     When 
paralysis  of  the  Facial  exists  in  Man,  the  sense  of  taste  is  very  much  impaired 
on  the  corresponding  side  of  the  tongue,  provided  the  cause  of  the  paralysis  be 
seated  above  the  origin  of  the  Chorda  Tympani  from  its  trunk.     Similar  results 
have  been  obtained  from  experiments  upon  other  animals.     The  nature  of  the 
influence  afforded  by  this  nerve  is  entirely  unknown  ;  and  it  is  the  more  obscure, 
as  the  Chorda  Tympani  contains  no  sensory  filaments. 

745.  To  the  sense  of  Touch,  all  the  afferent  nerves  of  the  body  (save  the 
nerves  of  special  sense)  appear  to  minister;  in  virtue — according  to  the  doctrine 
already  propounded — of  the  direct  connection  of  certain  of  their  fibrils  with  the 
Sensorium  commune.     But  the  degree  in  which  they  are  capable  of  producing 
Sensations  does  not  bear  any  constant  relation  to  their  power  of  exciting  reflex 
actions.     Thus,  the  Glosso-pharyngeal  is  not  nearly  so  sensitive  as  the  Fifth 
pair ;  though  more  powerful  as  an  excitor  nerve.     The  Par  Vagum  appears  to 
have  even  less  power  of  arousing  sensory  changes ;  although  it  is  the  most 
important  of  all  the  exciters  to  reflex  action.     So,  again,  the  afferent  nerves  of 
the  inferior  extremities,  in  Man,  are  less  concerned  in  ministering  to  sensations, 
than  are  those  of  the  superior ;  and  yet  they  appear  to  be  much  more  efficient 
as  exciters  to  muscular  action. — These  differences  may  be  accounted  for,  by 
supposing  that  the  proportion  which  the  fibres,  having  their  centre  in  the 


Archives  Generates  de  Medecine,"  1844. 


FUNCTIONS   OP   THE   SENSORY   GANGLIA.  719 

ganglionic  matter  of  the  Spinal  Cord,  bears  to  that  of  the  fibres  which  pass  on 
to  the  Sensorium,  is  not  constant,  but  is  liable  to  variation ;  the  former  pre- 
dominating in  the  Par  Vagum  and  the  G-losso-pharyngeal,  whilst  the  latter  are 
more  numerous  in  the  Fifth  Pair,  and  in  most  of  the  Spinal  nerves. 

746.  To  the  reflex  actions  of  the  Sensory  Ganglia,  all  the  motor  fibres  of  the 
Cranio-spinal  axis,  save  those   which  originate  in  its  Spinal  portion,  may  be 
considered  as  subservient;  for,  as  we  have  seen,  the  motor  columns  from  which 
proceed  the  anterior  roots  of  the  Spinal  nerves  and  the  motor  Encephalic  nerves, 
pass  up  into  the  Corpora  Striata  and  Corpora  Quadrigemina ;  and  although  the 
direct  connection  of  the  other  ganglia  of  Special  sense  with  the  motor  columns 
is  at  present  a  matter  of  presumption  only,  yet  this  presumption  is  strongly 
supported  by  the  analogy  of  the  Optic  ganglia,  the  distinctness  of  the  connection 
in  this  case  being  easily  accounted  for,  when  it  is  remembered  in  how  great  a 
degree  the  general  movements  of  the  body  are  guided  by  the  visual  sense.     This 
anatomical  evidence  is  fully  borne  out  by  the  results  of  experiment ;  since,  as 
we  have  seen  (§  738),  convulsive  movements  of  all  parts  of  the  body  may  be 
excited  by  the   application  of  the  electric  stimulus  to  this  division  of  the 
Encephalic  centres. 

747.  Functions  of  the  Sensory  Ganglia. — We  have  now  to  consider  what 
deductions  may  be  drawn  with  regard  to  the  functions  of  the  Sensory  Ganglia 
in  Man,  from  the  facts  supplied  by  Comparative  Anatomy,  Experimental  inquiry, 
and  Pathological  phenomena.     Here,  as  in  the  case  of  the  Spinal  Cord,  we  have 
to  distinguish  between  their  operation  as  independent  ganglionic  centres,  and 
their  action  in  subservience  to  the  Cerebrum,  which  is  superposed  upon  them. 
We  have  seen  reason  to  conclude  that,  in  their  former  capacity,  they  are  to.  be 
regarded  as  the  true  centres  of  Sensation  (i.  e.  of  the  consciousness  of  external 
impressions),  and  as  the  instrument,  in  virtue  of  their  own  "  reflex"  power,  of 
that  class  of  Instinctive  or  Automatic  movements,  which  require  to  be  prompted 
and  guided  by  sensations,  and  which  cannot,  therefore,  be  referred  to  the  excito- 
motor  group.     But  although  it  is  sufficiently  obvious  that  such  movements 
constitute  the  highest  manifestations  of  Animal  life  in  the  Invertebrata  generally, 
and  that  they  are  but  little  modified  by  any  higher  principle  of  action  even  in 
the  lower  Vertebrata,  yet  it  is  no  less  obvious  that  in  adult  Man,  in  whom  the 
Intelligence  and  Will  are  fully  developed,  we  have  comparatively  little  evidence 
of  this  independent  reflex  action  of  the  Sensory  Ganglia; — all  those  automatic 
actions  which  are  immediately  necessary  for  the  maintenance  of  his  Orgaadc  life 
being  provided  for  by  the  excito-motor  portion  of  the  apparatus,  so  that,  although 
sensation  ordinarily  accompanies  most  of  them,  it  is  not  essential  to  them; 
whilst  those  which  are  necessary  to  provide  more  remotely  for  its  requirements  are 
for  the  most  part  committed  to  the  guidance  of  his  Reason.     For  the  impressions 
which  have  been  brought  by  the  afferent  nerves  to  his  Sensorium,  and  which 
have  there  produced  sensations,  do  not  in  general  react  at  once  upon  the  motor 
apparatus  (as  they  do  in  those  animals  in  which  the  Sensory  Ganglia  are  the 
highest  of  the  nervous  centres),  but  usually  transmit  their  influence  upwards  to 
the  Cerebrum,  through  whose  instrumentality  they  give  rise  to  ideas  and  reason- 
ing processes,  which  operate  upon  the  motor  apparatus  either  emotionally  or 
volitionally.     And  it  is  for  the  most  part  only  when  this  upward  transmission 
is  checked,  either  by  the  non-development  or  the  functional  inactivity  of  the 
Cerebrum,  or  by  its  complete  occupation  in  some  other  train  of  action — or,  on 
the  other  hand,  when  the  reflex  action  of  the  Sensory  ganglia  is  called  into  play 
with  unusual  potency — that  we  have  any  manifestations  of  the  sensori-motor  or 
consensual  mode  of  operation  in  Man,  at  all  comparable  in  variety  or  importance 
to  those  which  are  so  remarkable  in  the  lower  animals. 

748.  Still,  sufficient  evidence  of  the  existence  of  this  class  of  reflex  move- 
ments may  be  drawn  from  observation  of  the  actions  of  Man  in  his  ordinary 


720  OF   THE   FUNCTIONS    OF   THE    NERVOUS    SYSTEM. 

condition ;  examples  of  it  being  furnished  (as  we  have  seen)  by  the  closure  of 
the  eyes  to  a  dazzling  light,  the  start  caused  by  a  loud  and  unexpected  sound, 
or  the  sneezing  excited  by  sensory  impressions  on  the  Schneiderian  membrane 
or  the  retina.  To  these  may  be  added  the  vomiting  produced  by  various  sensory 
impressions,  as  the  sight  of  a  loathsome  object,  a  disagreeable  smell,  a  nauseous 
taste,  or  that  peculiar  feeling  of  want  of  support  which  gives  rise  to  "  sea-sick- 
ness," especially  when  combined  with  the  sight  of  continually  shifting  lines  and 
surfaces,  which  itself  in  many  individuals  disposes  to  the  same  state ;  the  in- 
voluntary laughter  which  is  excited  by  tickling,  and  also  that  which  sometimes 
involuntarily  bursts  forth  at  the  provocation  of  some  sight  or  sound  to  which  no 
ludicrous  idea  or  emotion  can  be  attached ;  the  yawning  which  is  excited  by  an 
internal  sensation  of  uneasiness  (usually  arising  from  deficient  respiration),  or  by 
the  sight  or  sound  of  the  act  as  performed  by  another ;  and  those  involuntary 
movements  of  the  body  and  limbs,  excited  by  uneasy  sensations  (probably 
muscular),  which  are  commonly  designated  as  "  the  fidgets."  When  the  reflex 
activity  of  the  Sensory  ganglia  is  more  strongly  excited,  in  consequence  either 
of  an  unusual  potency  of  the  sensory  impressions,  or  of  an  unusual  excitability 
of  this  part  of  the  nervous  centres,  a  much  greater  variety  of  sensori-motor 
actions  is  witnessed.  The  powerful  involuntary  contraction  of  the  orbicularis 
and  of  the  muscles  which  roll  the  eyeball  upwards  and  inwards,  in  cases  of 
excessive  irritability  of  the  retina,  is  one  of  the  best  examples  of  this  kind ;  but 
another  very  curious  illustration  is  afforded  by  the  involuntary  abridgment 
of  the  excito-motor  actions  of  respiration  when  the  performance  of  these  is 
attended  with  pain — -the  dependence  of  this  abridgment  upon  the  direct  stimulus 
of  sensation,  rather  than  upon  voluntary  restraint,  being  obvious  from  the  fact 
that  it  often  presents  itself  on  one  side  only,  a  limitation  which  the  Will  cannot 
imitate.  Again,  there  are  certain  Convulsive  disorders  which  appear  to  depend 
upon  an  undue  excitability  of  these  centres,  the  paroxysms  being  excited  by 
impressions  which  act  through  the  organs  of  sense,  and  are  not  thus  operative 
unless  the  patient  be  conscious  of  them ;  thus  in  Hydrophobia,  we  observe  the 
immediate  influence  of  the  sight,  sound,  or  contact,  of  liquids,  or  of  the  slightest 
currents  of  air,  in  exciting  muscular  contractions ;  and  in  many  Hysteric  sub- 
jects, the  sight  of  a  paroxysm  in  another  individual  is  the  most  certain  means  of 
its  induction  in  themselves.  A  remarkable  case  of  this  general  exaltation  of 
purely  sensorial  excitability  has  been  recorded  by  Dr.  Cowan,  who  gives  the 
following  account  of  the  phenomena,  which  can  scarcely  be  referred  to  any  other 
than  this  category.  "  The  shadow  of  a  bird  crossing  the  window,  though  the 
blind  and  bed-curtains  are  closed,  the  displacement  of  the  smallest  portion  of 
the  wick  of  a  candle,  the  slightest  changes  in  the  firelight,  induce  a  sudden 
jerking  of  the  spinal  muscles,  extending  to  the  arms  and  legs  when  violent,  and 
this  without  the  slightest  mental  emotion  of  any  kind  beyond  a  consciousness 
of  the  movement.  At  times  the  vocal  organs  are  implicated,  and  a  slight  cry, 
quite  involuntary,  takes  place.  At  these  periods  she  is  unusually  susceptible  of 
all  noises,  especially  the  least  expected  and  least  familiar.  Movements  in  the 
next  house  inaudible  to  others,  the  slightest  rattle  in  the  lock  of  a  door,  tearing 
a  morsel  of  paper,  and  a  thousand  little  sources  of  sound  not  to  be  catalogued, 
induce  results  similar  to  those  of  visual  impressions."1 

749.  It  is,  however,  when  the  Cerebrum  is  not  in  a  state  which  renders  it 
capable  of  receiving  and  acting  upon  Sensorial  impressions,  that  we  find  the 
independent  reflex  activity  of  the  Sensory  ganglia  most  strikingly  displayed. 
Thus  in  the  Infant,  for  some  time  after  its  birth,  it  is  obvious  to  an  attentive 
observer  that  a  large  part  of  its  movements  are  directly  prompted  by  sensations 
to  which  it  can  as  yet  attach  no  distinct  ideas,  and  that  they  do  not  proceed 

1  "Lancet,"  Oct.  4,  1845. 


FUNCTIONS   OF   THE   SENSORY   GANGLIA.  721 

from  that  purposive  impulse  which  is  essential  to  render  them  voluntary.  This 
is  well  seen  in  the  efforts  which  it  makes  to  find  the  nipple  with  its  lips;  being 
probably  guided  thereto  at  first  by  the  smell,  but  afterwards  by  the  sight  also ; 
when  the  nipple  has  been  found,  the  act  of  suction  is  purely  excito-motor,  as 
already  explained.  So  in  the  idiot,  whose  brain  has  never  attained  its  normal 
development,  the  influence  of  sensations  in  directly  producing  respondent  move- 
ments is  obvious  to  all  who  examine  them  with  discrimination;  and  a  remark- 
able case  will  be  cited  hereafter  (Sect.  7),  in  which  an  entire  though  temporary 
suspension  of  Cerebral  power,  reducing  the  subject  of  it  to  the  condition  of  one 
of  the  lowest  Vertebrata,  gave  a  very  satisfactory  proof  of  the  independent  power 
of  this  division  of  the  Encephalic  centres. — But  we  do  not  require  to  go  so  far 
in  search  of  characteristic  examples  of  this  kind  of  reflex  action ;  since  they  are 
afforded,  as  already  remarked,  by  the  performance  of  habitual  movements,  which 
are  clearly  under  Sensorial  guidance,  when  the  Cerebrum  is  occupied  in  some 
train  of  action  altogether  disconnected  with  them.  An  individual  who  is  subject 
to  "absence  of  mind"  may  fall  into  a  reverie  whilst  walking  the  streets,  his 
whole  attention  may  be  absorbed  in  his  train  of  thought,  and  he  may  be  utterly 
unconscious  of  any  interruption  in  its  continuity;  and  yet,  during  the  whole  of 
that  time,  his  limbs  shall  have  been  in  motion,  carrying  him  along  the  accus- 
tomed path,  whilst  his  vision  shall  have  given  the  direction  to  these  movements, 
which  is  requisite  to  guide  him  along  a  particular  line,  or  to  move  him  out  of 
it  for  the  avoidance  of  obstacles.  As  already  remarked  (§  726),  there  seems 
strong  reason  for  regarding  the  ambulatory  movements  of  the  limbs  as  in  them- 
selves excito-motor;  but  the  guidance  of  these  movements  by  the  visual  sense 
marks  the  participation  of  the  Sensorium  in  this  remarkable  performance.  It 
has  been  maintained  by  some  Metaphysicians  and  Physiologists  that  these 
" secondarily  automatic"  actions  always  continue  to  be  voluntary,  because  their 
performance  is  originally  due  to  a  succession  of  volitional  acts,  and  because,  in 
any  particular  case,  it  is  the  will  which  first  excites  them,  whilst  an  exertion  of 
the  will  serves  to  check  them  at  any  time.  But  this  doctrine  involves  the 
notion,  that  the  will  is  in  a  state  of  pendulum-like  oscillation  between  the  train 
of  thought  and  the  train  of  movement;  whereas  nothing  is  more  certain  to  the 
individual  who  is  the  subject  of  both,  than  that  the  former  may  be  as  uninter- 
rupted as  if  his  body  were  perfectly  at  rest,  and  his  reverie  were  taking  place 
in  the  quietude  of  his  own  study.  And  as  it  commonly  happens  that  the 
direction  taken  is  that  in  which  the  individual  is  most  in  the  habit  of  walking, 
it  will  not  unfrequently  occur  that,  if  he  had  previously  intended  to  pursue  some 
other,  he  finds  himself,  when  his  reverie  is  at  an  end,  in  a  locality  which  may 
be  very  remote  from  that  towards  which  his  walk  was  originally  destined;  which 
would  not  be  the  case,  if  his  movements  had  been  still  under  the  purposive 
direction  of  the  will.  And  although  it  is  perfectly  true  that  these  movements 
can  be  at  any  time  checked  by  an  effort  of  the  will,  yet  this  does  not  really 
indicate  that  the  will  has  been  previously  engaged  in  sustaining  them ;  since, 
for  the  will  to  act  upon  them  at  all,  the  attention  must  be  recalled  to  them,  and 
the  Cerebrum  must  be  liberated  from  its  previous  self-occupation.  And  the 
gradual  conversion  of  a  volitional  into  an  automatic  train  of  movements,  so  that 
at  last  the  train,  once  started,  shall  continue  to  run  down  of  itself,  will  be  found 
to  be  less  improbable  than  it  would  at  first  appear,  when  it  comes  to  be  under- 
stood that  the  mechanism  of  both  sets  of  actions  is  essentially  the  same,  and 
that  they  merely  differ  as  regards  the  nature  of  the  stimulus  which  originallv 
excites  them  (§  757).  That  the  same  automatic  movements  are  not  excited 
by  the  same  sensations,  when  the  Cerebrum  is  in  its  ordinary  state  of  functional 
connection  with  the  Sensorium,  is  a  fact  entirely  in  harmoDy  with  the  principle 
already  laid  down  (§§  683 — 6).  The  complete  occupation  of  the  mind  in  other 
ways,  as  in  close  conversation  or  argument,  or  even  (it  may  be)  in  the  voluntary 


722  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

direction  of  some  other  train  of  muscular  movements,  is  no  less  favorable  than 
the  state  of  reverie  to  that  independent  action  of  the  Automatic  centres  which 
has  been  now  described. 

750.  In  the  state  of  entire  functional  activity  of  the  nervous  centres  of  Man, 
however,  there  can  be  no  doubt  that  the  operation  of  the  Sensory  Ganglia  is 
entirely  subordinated  to  that  of  the  Cerebrum;  and  that  it  furnishes  an  essential 
means  of  connection  between  the  actions  of  the  Cerebrum  on  the  one  hand,  and 
those  of  the  organs  of  Sense  and  Motion  on  the  other,  by  the  combination  of 
which  the  Mind  is  brought  into  relation  with  the  external  world.     For,  in  the 
first  place,  it  may  be  affirmed  with  certainty  that  no  mental  action  can  be  excited 
in  the  first  instance,  save  by  the  stimulus  of  Sensations;  and  it  is  the  office  of 
the  Sensory  ganglia  to  form  these  out  of  the  impressions  brought  to  them  from 
the  organs  of  sepse,  and  to  transmit  such  sensorial  changes  to  the  Cerebrum.    But 
they  have  a  no  less  important  participation  in  the  downward  action  of  the  Cere- 
brum upon  the  motor  apparatus;  for  no  voluntary  action  can  be  performed  without 
the  assistance  of  a  guiding  Sensation,  as  was  first  prominently  stated  by  Sir  C. 
Bell.1 — In  the  majority  of  cases,  the  guiding  or  controlling  sensation  is  derived 
from  the  muscles  themselves,  of  whose  condition  we  are  rendered  cognizant  by 
the  sensory  nerves  with  which  they  are  furnished ;  but  there  are  certain  cases  in 
which  it  is  ordinarily  derived  from  one  of  the  special  senses,  arid  in  which  the  mus- 
cular sense  can  only  imperfectly  supply  the  deficiency  of  such  guidance;  whilst 
again,  if  the  muscular  sense  be  deficient,  one  of  the  special  senses  may  supply 
the  requisite  information.     The  proof  of  this  necessity  is  furnished  by  the  entire 
impossibility  of  making  or  sustaining  voluntary  efforts  without  a  guiding  sensa- 
tion of  some  kind.     Thus,  in  complete  anaesthesia  of  the  lower  extremities,  with- 
out loss  of  muscular  power,  the  patient  is  as  completely  unable  to  walk  as  if 
the  motor  nerves  had  also  been  paralyzed,  unless  the  deficient  sensorial  guidance 
be  replaced  by  some  other;  and  in  similar  affections  of  the  upper  extremities, 
there  is  a  like  inability  to  raise  the  limb  or  to  sustain  a  weight.     But  in  such 
cases,  the  deficiency  of  the  "muscular  sense"  may  be  made  good  by  the  visual; 
thus  the  patient  who  cannot  feel  either  the  contact  of  his  foot  with  the  ground,  or 
the  muscular  effort  he  is  making,  can  manage  to  stand  and  walk  if  he  look  at  his 
limbs;  and  the  woman  who  cannot  feel  the  pressure  of  her  child  upon  her  arms, 
can  yet  sustain  it  as  long  as  she  keeps  her  eyes  fixed  upon  it,  but  no  longer — 
the  muscles  ceasing  to  contract,  and  the  limb  dropping  powerless,  the  moment 
that  the  eyes  are  withdrawn  from  it.     Thus  it  is,  too,  that  when  we  are  about  to 
make  a  muscular  effort,  the  amount  of  force  which  we  put  forth  is  governed  by 
the  mental  conception  of  that  which  will  be  required,  as  indicated  by  the  ex- 
perience of  former  sensations ;  just  as  the  contractions  of  the  muscles  of  vocaliza- 
tion are  regulated  by  the  conception  of  the  sound  to  be  produced.     Hence  if  the 
weight  be  unknown  to  us,  and  it  prove  either  much  heavier  or  much  lighter 
than  was  expected,  we  find  that  we  have  put  forth  too  little  or  too  great  a  mus- 
cular effort. 

751.  There  are  two  groups  of  muscular  actions,  however,  which,  although  as 
voluntary  in  their  character  as  the  foregoing,  are  yet  habitually  guided  by  other 
sensations  than  those  derived  from  the  muscles   themselves.     These  are  the 
movements  of  the  eyeball,  and  those  of  the  vocal  apparatus. — The  former  are 
directed  by  the  visual  sense,3  by  which  the  action  of  the  muscles  is  guided  and 
controlled,  in  the  same  manner  as  that  of  other  muscles  is  directed  by  their  own 
"muscular  sense ;"  and  hence  it  happens  that,  when  we  close  our  eyes,  we  cannot 

1  See  his  chapter  "On  the  Nervous  Circle  which  connects  the  voluntary  muscles  with 
the  Brain,"  in  his  work  "  On  the  Nervous  System  of  the  Human  Body." 

2  See  Dr.  Alison's  Memoir  on  the  "  Anatomical  and  Physiological  Inferences  from  the 
Study  of  the  Nerves  of  the  Orbit,"  in  "Trans,  of  Roy.  Soc.  of  Edinb.,"  vol.  xv. 


FUNCTIONS   OP   THE    SENSORY   GANGLIA.  723 

move  them  in  any  required  direction,  without  an  effort  that  strongly  calls  forth 
the  muscular  sense,  by  which  the  action  is  then  guided.  In  persons  who  have 
become  blind  after  having  once  enjoyed  sight,  an  association  is  formed  by  habit 
between  the  muscular  sense  and  the  contractile  action,  that  enables  the  former 
to  serve  as  the  guide  after  the  loss  of  the  visual  sense;  but  in  those  who  are 
born  perfectly  blind,  or  who  have  become  so  in  early  infancy,  this  association  is 
never  formed,  and  the  eyes  of  such  persons  exhibit  a  continued  indefinite  move- 
ment, and  cannot  by  any  amount  of  effort  be  steadily  fixed  in  one  spot,  or  be 
turned  in  any  definite  direction.  A  very  small  amount  of  the  visual  sense, 
however,  such  as  serves  merely  to  indicate  the  direction  of  light,  is  sufficient  for 
the  government  of  the  movements  of  the  eyeball. — In  the  production  of  vocal 
sounds,  again,  that  nice  adjustment  of  the  muscles  of  the  larynx,  which  is  re- 
quisite to  give  forth  determinate  tones,  is  ordinarily  directed  by  the  auditory 
sense  :  being  learned  in  the  first  instance  under  the  guidance  of  the  sounds  actu- 
ally produced;  but  being  subsequently  effected  voluntarily,  in  accordance  with 
the  mental  conception  (a  sort  of  inward  sensation)  of  the  tone  to  be  uttered, 
which  conception  cannot  be  formed,  unless  the  sense  of  hearing  has  previously 
brought  similar  tones  to  the  mind.  Hence  it  is  that  persons  who  are  born 
deafj  are  also  dutnb.  They  may  have  no  malformation  of  the  organs  of  speech; 
but  they  are  incapable  of  uttering  distinct  vocal  sounds  or  musical  tones,  because 
they  have  not  the  guiding  conception,  or  recalled  sensation,  of  the  nature  of  these. 
By  long  training,  however,  and  by  imitative  efforts  directed  by  muscular  sensa- 
tions in  the  larynx  itself,  some  persons  thus  circumstanced  have  acquired  the 
power  of  speech  :  but  the  want  of  a  sufficiently  definite  control  over  the  vocal 
muscles  is  always  very  evident  in  their  use  of  the  organ.  It  is  very  rarely  that 
a  person  who  has  once  enjoyed  the  sense  of  hearing  afterwards  becomes  so  com- 
pletely deaf  as  to  lose  all  auditory  control  over  his  vocal  organs.  An  example  of 
this  kind,  however,  has  been  made  known  to  the  public  by  a  well-known  author 
as  having  occurred  in  himself;  and  the  record  of  his  experiences1  contains  many 
points  of  much  interest.  The  deafness  was  the  result  of  an  accident  occurring  in 
childhood,  which  left  him  for  some  time  in  a  state  of  extreme  debility;  and 
when  he  made  the  attempt  to  speak,  it  was  with  considerable  pain  in  the  vocal 
organs.  This  pain  probably  resulted  from  the  unaccustomed  effort  which  it  was 
necessary  to  make,  when  the  usual  guidance  was  wanting ;  being  analogous  to 
the  uneasiness  which  we  experience  when  we  attempt  to  move  our  eyes  with 
the  lids  closed.  His  voice  at  that  time  is  described  as  being  very  similar  to 
that  of  a  person  born  deaf  and  dumb,  but  who  has  been  taught  to  speak.  With 
the  uneasiness  in  the  use  of  the  vocal  organs  was  associated  an  extreme  mental 
indisposition  to  their  employment ;  and  thus,  for  some  years,  the  voice  was  very 
little  exercised.  Circumstances  afterwards  forced  it,  however,  into  constant 
employment;  and  great  improvement  subsequently  took  place  in  the  power  of 
vocalization,  evidently  by  attention  to  the  indications  of  the  muscular  sense.  It 
is  a  curious  circumstance,  fully  confirming  this  view,  that  the  words  which  had 
been  in  use  previously  to  the  supervention  of  the  deafness,  are  still  pronounced 
(such  of  them,  at  least,  as  are  kept  in  employment)  as  they  had  been  in  child- 
hood; the  muscular  movements  concerned  in  their  articulation  being  still  guided 
by  the  original  auditory  conception,  in  spite  of  the  knowledge  derived  from  the 
information  of  others,  that  such  pronunciation  is  erroneous.  On  the  other  hand, 
all  the  words  subsequently  learned  are  pronounced  according  to  their  spelling ; 
the  acquired  associations  between  the  muscular  sensations  and  the  written  signs 
being  in  this  case  the  obvious  guide. 

752.  It  is  through  the  muscular  sense,  in  combination  with  the  visual  and 
tactile,  that  those  movements  are   regulated  which  are  concerned  alike  in  ordi- 

1  See  the  "  Lost  Senses,"  by  Dr.  Kitto  ;  vol.  i.  chapters  2  and  3. 


724  OF  THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

nary  progression,  and  in  the  maintenance  of  the  equilibrium  of  the  body.  That 
the  visual  sense  has,  in  most  persons,  a  large  share  in  this  regulation,  is  evident 
from  the  simple  fact  that  no  one  who  has  not  been  accustomed  to  the  depriva- 
tion of  it  can  continue  to  walk  straight-forwards,  when  blindfolded,  or  in  abso- 
lute darkness,  towards  any  point  in  the  direction  of  which  he  may  have  been 
at  first  guided.  But  the  blind  man,  who  has  been  accustomed  to  rely  exclu- 
sively upon  his  muscular  sense,  has  no  difficulty  in  keeping  to  a  straight  path ; 
and  moves  onwards  with  a  confidence  which  is  in  remarkable  contrast  with  the 
gait  of  a  man  who  has  been  deprived  of  sight  for  the  occasion  only.  In  fact, 
as  Mr.  Mayo  has  well  remarked,1  in  our  ordinary  movements,  "  we  lean  upon 
our  eyesight  as  upon  crutches."  And  when  our  vision,  instead  of  aiding  and 
guiding  us,  brings  to  the  mind  sensations  of  an  antagonistic  character,  our 
movements  become  uncertain,  from  the  loss  of  that  power  of  guidance  and 
control  over  them  which  the  harmony  of  the  two  sensations  usually  gives. 
Thus  a  person  unaccustomed  to  look  down  heights  feds,  insecure  at  the  top  of  a 
tower  or  a  precipice,  although  he  knows  that  his  body  is  properly  supported ; 
for  the  void  which  he  sees  below  him  contradicts  (so  to  speak)  the  tactile  sensa- 
tions by  which  he  is  made  conscious  of  the  due  equilibrium  of  his  body.  So, 
again,  any  one  can  walk  along  a  narrow  plank  which  forms  part  of  the  floor  of 
a  room,  or  which  is  elevated  but  a  little  above  it,  without  the  least  difficulty, 
and  even  without  any  consciousness  of  effort.  But  let  that  plank  extend  across 
a  chasm,  the  bottom  of  which  is  so  far  removed  from  the  eye  that  the  visual 
sense  gives  no  assistance;  and  even  those  who  have  braced  their  nerves  against 
all  emotional  distraction,  feel  that  an  effort  is  requisite  to  maintain  the  equili- 
brium during  their  passage  over  it ;  that  effort  being  aided  by  the  withdrawal 
of  the  eyes  from  the  abyss  below,  and  the  fixation  of  them  on  a  point  beyond, 
which  at  the  same  time  helps  to  give  steadiness  to  the  movements,  and  distracts 
the  mind  from  the  sense  of  its  danger.  The  degree  in  which  the  muscular 
sense  is  alone  sufficient  for  the  guidance  of  such  movements,  when  the  mind  has 
no  consciousness  of  the  danger,  and  when  the  visual  sense  neither  affords  aid 
nor  contributes  to  distract  the  attention,  is  remarkably  illustrated  by  the  phe- 
nomena of  Somnambulism;  for  the  sleep-walker  traverses,  without  the  least  hesi- 
tation, the  narrow  parapet  of  a  house,  and  crosses  narrow  and  insecure  planks, 
clambers  roofs,  &c.,  under  circumstances  that  clearly  indicate  the  nature  of  the 
guidance  by  which  he  is  directed  (see  Sect.  7). — The  dependence  of  our  ordi- 
nary power  of  maintaining  our  equilibrium  upon  the  combination  of  the 
guiding  sensations  derived  through  the  sight  and  the  touch,  is  further  well 
illustrated,  as  Mr.  Mayo  has  pointed  out  (loc.  cit.),  by  what  happens  to  a  lands- 
man on  first  going  to  sea.  "  It  is  long  before  the  passenger  acquires  his  l  sea 
legs/  At  first,  as  the  ship  moves,  he  can  hardly  keep  his  feet;  the  shifting 
lines  of  the  vessel  and  surface  of  the  water  unsettle  his  visual  stability ;  the 
different  inclinations  of  the  planks  he  stands  on,  his  muscular  sense.  In  a 
short  time,  he  learns  to  disregard  the  shifting  images  and  changing  motions,  or 
acquires  facility  in  adapting  himself  (like  one  on  horseback)  to  the  different 
alterations  in  the  line  of  direction  in  his  frame."  And  when  a  person  who  has 
thus  learned  by  habit  to  maintain  his  equilibrium  on  a  shifting  surface,  first 
treads  upon  firm  ground,  he  feels  himself  almost  as  much  at  fault  as  he  did 
when  he  first  went  to  sea;  and  it  is  only  after  being  some  time  on  shore,  that 
he  is  able  to  resume  his  original  manner  of  walking.  Indeed,  most  of  those 
who  spend  the  greater  part  of  their  time  at  sea  acquire  a  peculiar  gait,  which 
becomes  so  habitual  to  them  that  they  are  never  able  to  throw  it  off. 

753.  But,  further,  there  is  very  strong  physiological  evidence  that  the  Sen- 
sory Ganglia  are  not  merely  the  instruments  whereby  our  voluntary  movements 

1  "Outlines  of  Physiology,"  p.  355. 


FUNCTIONS   OF   THE    SENSORY   GANGLIA.  725 

are  directed  and  controlled,  in  virtue  of  the  guiding  sensations  which  they 
furnish,  but  that  they  are  actually  the  immediate  centres  of  the  motor  influence 
which  excites  muscular  contractions,  in  obedience  to  impulses  transmitted 
downwards  from  the  Cerebrum.  It  has  usually  been  considered  that  the  Cere- 
brum acts  directly  upon  the  muscles  through  the  motor  nerves,  in  virtue  of  a 
direct  continuity  of  fibres  from  the  gray  matter  of  its  convolutions,  through  the 
Corpora  Striata,  the  motor  tract  of  the  Medulla  Oblongata,  the  anterior  portion 
of  the  Spinal  Cord,  and  the  anterior  roots  of  the  nerves ;  and  that  in  the  per- 
formance of  any  voluntary  movement,  the  Will  determines  the  motor  force  to 
the  muscle  or  set  of  muscles  by  whose  instrumentality  it  may  be  produced.  To 
this  doctrine,  however,  the  anatomical  facts  already  stated  (§  730)  constitute  a 
very  serious  objection;  for  the  motor  tract  cannot  be  stated  with  certainty  to 
have  any  higher  origin  than  the  Corpora  Striata;  and  it  is  impossible  to  imagine 
that  the  fibres  which  converge  towards  the  surface  of  these  bodies  from  all  parts 
of  the  Cerebrum  can  be  so  closely  compacted  together  as  to  be  included  in  the 
motor  columns  of  the  Spinal  Axis.  The  fact  would  rather  seem  to  be  that 
these  converging  fibres  bear  the  same  kind  of  anatomical  relation  to  the  Cor- 
pora Striata  and  the  other  Sensorial  centres  of  motor  power,  as  do  the  fibres  of 
the  afferent  nerves  which  proceed  to  them  from  the  Retina,  the  Schneiderian 
membrane,  and  other  peripheral  expansions  of  nervous  matter;  and  hence  we 
might  infer  that  the  nerve-force  generated  in  the  convolutions,  instead  of  acting 
immediately  on  the  motor  nerves,  is  first  directed  towards  the  Automatic  centres, 
and  excites  the  same  kind  of  motor  response  in  them  as  would  be  given  to  an 
impression  transmitted  to  them  through  a  sensory  nerve.  We  shall  find  that 
such  a  view  of  the  structural  arrangements  of  these  parts  is  in  remarkable 
accordance  with  their  functional  relations,  as  indicated  by  a  careful  analysis  of  the 
mechanism  of  what  is  commonly  regarded  as  voluntary  movement.  The  Cerebrum, 
as  will  be  shown  hereafter  (Sect.  5),  may  thus  call  the  Automatic  apparatus  into 
action,  as  the  instrument  either  of  ideas,  of  emotions,  or  of  volitional  determi- 
nations; but  as  both  the  ideo-motor  and  the  emotional  movements  have  much 
in  common  with  the  automatic,  there  is  no  occasion  for  at  present  specially 
inquiring  into  their  mechanism,  and  we  may  limit  our  examination  to  voluntary 
movements  alone,  which  have  been  usually  regarded  as  in  such  complete  an- 
tagonism to  those  of  the  automatic  group,  that  even  distinct  sets  of  nerve-fibres 
have  been  thought  requisite  to  account  for  the  transmission  of  these  two  sets  of 
motor  impulses  to  the  muscles. 

754.  Now  in  the  first  place  it  may  be  asserted  with  some  confidence,  that  no 
effort  of  the  Will  can  exert  that  direct  influence  on  the  muscles  which  our 
ordinary  phraseology,  and  even  the  language  of  scientific  reasoners,  would  seem 
to  imply ;  but,  on  the  other  hand,  that  the  Will  is  solely  concerned  in  deter- 
mining the  result,  the  selection  and  combination  of  muscular  movements  required 
to  bring  about  this  result  not  being  effected  by  the  Will,  but  by  some  inter- 
mediate agency.  If  it  were  otherwise,  we  should  be  dependent  upon  anatomical 
knowledge  for  our  power  of  performing  the  simplest  movement  of  the  body ; 
whereas  we  find  the  fact  to  be,  that  the  man  who  has  not  the  least  idea  of  the 
mechanism  of  muscular  action  can  acquire  the  most  perfect  command  over  his 
movements,  and  can  adapt  them  as  perfectly  to  the  desired  end  as  the  most 
accomplished  anatomist  could  do.  Further,  we  cannot,  by  any  exertion  of  the 
will,  single  out  a  particular  muscle  and  throw  it  into  contraction  by  itself,  unless 
that  muscle  be  one  which  is  alone  concerned  in  an  action  that  we  can  voluntarily 
perform;  and  even  then  we  single  it  out  by  willing  the  action.  Thus  we  can 
put  the  levator  palpebrse  in  action  by  itself;  but  this  we  do,  not  by  any  conscious 
determination  of  power  to  the  muscle  itself,  but  by  willing  to  raise  the  eyelids; 
and  it  is  only  by  our  anatomical  knowledge  that  we  know  that  but  a  single 
muscle  is  concerned  in  this  movement.  So  far  as  our  own  consciousness  can 


726  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

inform  us,  there  is  no  difference  between  the  mechanism  of  this  action  and  that 
of  the  flexion  of  the  knee  or  elbow-joint;  and  yet  in  these  latter  movements, 
several  muscles  are  concerned,  not  one  of  which  can  be  singled  out  by  an  effort 
of  the  will,  and  thrown  into  action  separately  from  the  rest. — The  idea  that  the 
will  is  directly  exerted  upon  the  muscles  called  into  action  to  produce  a  particular 
movement,  may  seem  to  derive  some  support  from  the  sense  of  effort  of  which 
we  are  conscious  in  making  the  exertion,  and  which  we  refer  to  the  muscles 
which  are  concerned  in  it;  but  this  sense  of  effort  is  nothing  else  than  the 
"  muscular  sense "  already  alluded  to,  which  has  its  origin  in  the  state  of  tension 
of  the  muscles,  and  which  is  no  more  an  indication  of  mental  effort  directed  to 
them,  than  the  sensation  of  light  or  sound  is  an  indication  of  a  determination  of 
voluntary  power  to  the  eyes  or  ears. 

755.  There  are  two  cases  in  which  it  is  very  easy  to  show  that  the  Will  is 
concerned  with  the  result  alone,  and  is  not  directly  exerted  upon  the  instruments 
by  which  that  result  is  brought  about.     These  are,  the  movements  of  the  Eyes, 
and  the  production  of  Vocal  tones.     In  neither  of  these  are  we  conscious  of  any 
effort  in  the  muscular  apparatus,  unless  the  contraction  be  carried  beyond  its 
accustomed  extent;  the   ordinary  movements  being  governed,  as  already  re- 
marked, not  by  the  muscular  sense,  but  by  the  visual  and  auditory  senses  respect- 
ively.— Nothing  can  be  more  simple,  to  all  appearance,  than  the  act  of  turning 
the  eyes  upwards  or  downwards,  to  one  side  or  the  other,  in  obedience  to  a 
determination  of  the  Will;  and  yet  the  Will  does  not  impress  such  a  determi- 
nation upon  the  muscles.     That  which  the  Will  really  does  is  to  cause  the 
eyeball  to  roll  in  a  given  direction,  in  accordance  with  a  visual  sensation;  and 
it  is  only  when  there  is  an  object  towards  which  the  eyes  can  be  turned,  that  we 
can  move  them  with  our  usual  facility.     When  the  eyelids  are  closed,  and  we 
attempt  to  roll  the  globes  upwards  or  downwards,  to  one  side  or  the  other,  we 
feel  that  we  can  do  so  but  very  imperfectly,  and  with  a  sense  of  effort  referred 
to  the  muscles  themselves, — this  sense  being  the  result  of  the  state  of  tension 
in  which  the  muscles  are  placed,  by  the  effort  to  move  the  eyes  without  the 
guiding  visual  sensation.     Now,  on  the  other  hand,  the  Will  may  determine  to 
fix  the  eyes  upon  an  object;  and  yet  this  very  fixation  may  be  only  attainable 
by  a  muscular  movement, — which  movement  is  directly  excited  by  the  visual 
sense,  without  any  exertion  of  voluntary  power  over  the  muscles.     Such  is  the 
case  when  we  look  steadily  at  an  object,  whilst  we  move  the  head  horizontally 
from  side  to  side;  for  the  eyeballs  will  then  be  moved  in  the  contrary  direction 
by  a  kind  of  instinctive  effort  of  the  external  and  internal  recti,  which  tends  to 
keep  the  retinae   in  their  first  position,  and  to  prevent  the  motion  of  the  images 
over  them.    So,  when  we  look  steadily  at  an  object,  and  incline  the  head  towards 
either  shoulder,  the  eyeballs  are  rotated  upon  their  antero-posterior  axis  (proba- 
bly by  the  agency  of  the  oblique  muscles)  apparently  with  the  very  same  pur- 
pose,— that  of  preventing  the  images  from  moving  over  the  retinae.     Now  we 
cannot  refuse  to  this  rotation  any  of  the  attributes  which  really  characterize  the 
so-called  voluntary  movements;  and  yet  we  are  not  even  informed  by  our  own 
consciousness  that  such  a  movement  is  taking  place,  and  know  it  only  by  ob- 
servation of  others. 

756.  The  muscular  contractions  which  are  concerned  in  the  production  of 
vocal  tones  are,  in  like  manner,  always  accounted  voluntary;  and  yet  it  is  easy 
to  show  that  the  Will  has  no  direct  power  over  the  muscles  of  the  larynx.     For 
we  cannot  raise  or  depress  the  larynx  as  a  whole,  nor  move  the  thyroid  cartilage 
upon  the  cricoid,  nor  separate  or  approximate  the  arytenoid  cartilages,  nor  ex- 
tend or  relax  the  vocal  ligaments,  by  simply  willing  to  do  so,  however  strongly. 
Yet  we  can  readily  do  any  or  all  these  things  by  an  act  of  the  Will  exerted  for 
a  specific  purpose.     We  conceive  of  a  tone  to  be  produced,  and  we  will  to  pro- 
duce it;  a  certain  combination  of  the  muscular  actions  of  the  larynx  then  takes 


FUNCTIONS   OF   THE    SENSORY   GANGLIA.  727 

place,  in  most  exact  accordance  one  with  another;  and  the  predetermined  tone 
is  the  result.  This  anticipated  or  conceived  sensation  is  the  guide  to  the  mus- 
cular movements,  when  as  yet  the  utterance  of  the  voice  has  not  taken  place ; 
but  whilst  we  are  in  the  act  of  speaking  or  singing,  the  contractile  actions  are 
regulated  by  the  present  sensations  derived  from  the  sounds  as  they  are  produced. 
It  can  scarcely  but  be  admitted,  then,  that  the  Will  does  not  directly  govern 
the  movements  of  the  Larynx;  but  that  these  movements  are  immediately 
dependent  upon  some  other  agency. 

757.  Now  what  is  true  of  the  two  preceding  classes  of  actions  is  equally  true 
of  all  the  rest  of  the  so-called  voluntary  movements;  for  in  all  of  them  the 
power  of  the  Will  is  really  limited  to  the  determination  of  the  result;  and  the 
production  of  that  result  is  entirely  dependent  upon  the  concurrence  of  a  "guid- 
ing sensation/'  which  is  usually  furnished  by  the  very  muscles  that  are  called 
into  action.     It  is  obvious,  therefore,  that  we  have  to  seek  for  some  intermediate 
agency,  which  executes  the  actions  determined  by  the  Will ;  and  when  the  facts 
and  probabilities  already  stated  are  duly  considered,  they  tend  strongly  in  favor 
of  the  idea  that  even  Voluntary  movements  are  executed  by  the  instrumental- 
ity of  the  Automatic  apparatus,  and  that  they  differ  only  from  the  automatic  or 
instinctive  in  the  nature  of  the  stimulus  by  which  they  are  excited — the  deter- 
mination of  the  Will  here  replacing,  as  the  exciting  cause  of  its  action,  the 
sensory  impression  which  operates  as  such  in  the  case  of  an  instinctive  move- 
ment, and  which  is  still  requisite  for  its  guidance. 

758.  This  view  of  the  case  derives  a  remarkable  confirmation  from  the  ana» 
lysis  of  two  classes  of  phenomena ;  the  first  consisting  of  cases  in  which  move- 
ments that  are  ordinarily  automatic  are  performed  by  voluntary  determination, 
or  simply  in  respondence  to  an  idea;  the  second  consisting  of  those  in  which 
movements  originally  voluntary  come  by  habit  to  be  automatically  performed. 
— Of  the  first  class,  the  act  of  Coughing  is  a  good  example.     This  action,  which 
is  ordinarily  automatic,  may  also  be  excited  by  a  voluntary  determination ;  such 
a  determination,  however,  is  directed  to  the  result,  rather  than  exercised  in 
singling  out  the  different  movements  and  then  combining  them  in  the  necessary 
sequence;  and  it  thus  seems  obviously  to  take  the  place  of  the  laryngeal  or 
tracheal  irritation,  as  the  primum  mobile  of  the  series,  which,  in  its  actual  per- 
formance, is  as  automatic  in  the  latter  case  as  in  the  former.     So,  again,  we 
know  that  many  of  the  automatic  movements  which  have  been  already  referred  to 
as  examples  of  the  sensori-motor  group  (§  748),  and  which  the  Will  cannot  call 
forth,  may  be  performed  in  respondence  to  ideas  or  conceptions,  which  are  Cere- 
bral states  that  seem  to  recal  the  same  condition  of  the  Sensorium  as  that  which 
was  originally  excited  by  the  Sensory  impression.     Thus  it  is  well  known  that 
the  act  of  Vomiting  may  be  induced  by  the  remembrance  of  some  loathsome  ob- 
ject or  nauseous  taste,  which  may  have  been  excited  by  some  act  of  "suggestion ;" 
and  the  author  has  known  an  instance  in  which  a  violent  fit  of  sea-sickness  was 
brought  on  by  the  sight  of  a  vessel  tossed  about  at  sea,  which  recalled  the  former 
experience  of  that  state.     So,  the  Hydrophobic  paroxysm  may  be  excited  by 
the  mention  of  the  name  of  water,  which  of  course  calls  up  the  idea;  and  a 
tendency  to  yawn  is  in  like  manner  frequently  induced  by  looking  at  a  picture 
of  yawners,  or  by  speaking  of  the  act,  or  by  voluntarily  commencing  the  act, 
which  may  then  be  automatically  completed. — The  automatic  performance  of 
actions  which  were  originally  voluntary  has  already  been  fully  discussed  (§  749); 
and  we  have  therefore  only  to  remark  here  that  the  fact  very  strongly  supports 
the  view  now  advanced,  as  to  the  singleness  of  the  mechanism  which  serves  as 
the  instrument  of  both  classes  of  actions,  and  the  essential  uniformity  of  its 
operation  in  the  two  cases. — It  would  be  difficult  to  explain  either  set  of  pheno- 
mena satisfactorily  on  the  hypothesis  that  there  is  a  "distinct  system"  of  fibres 


728  OF   THE    FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

for  the  volitional  and  for  the  automatic  movements ;  since  it  is  not  readily  to  be 
conceived  how  a  set  of  movements  originally  performed  by  the  one,  can  ever 
be  transferred  to  the  other ;  whilst,  on  the  other  hand,  it  is  easy  to  understand 
how  the  same  motorial  action  may  be  excited  in  the  automatic  centres,  either 
by  an  external  impression  conveyed  thither  by  an  afferent  nerve  from  a  Sensory 
surface  (as  that  of  the  irritation  in  the  air-passages,  which  excites  the  act  of 
coughing),  or  by  a  stimulus  proceeding  from  the  convoluted  surface  of  the  Cere- 
brum, and  conveyed  along  those  connecting  fibres  which  Reil  with  great  sagacity 
termed  the  ''nerves  of  the  internal  senses/' 

759.  To  sum  up,  then,  we  seem  justified  in  concluding  that  the  Cranio- Spinal 
Axis  of  Man  and  other  Vertebrata — consisting  of  the  Sensory  Ganglia,  Medulla 
Oblongata,  and  Spinal  Cord — is  (like  the  chain  of  cephalic  and  ventral  ganglia 
of  Articulata  with  which  it  is  homologous)  the  immediate  instrument  of  all  sen- 
sorial  and  motor  changes;  that  by  its  sole  and  independent  action  are  produced 
all  those  movements  which  are  ranked  as  automatic  or  instinctive,  these  being 
performed  in  respondence  to  external  impressions  which  may  or  may  not  affect 
the  consciousness ;  but  that  when  acting  in  subordination  to  the  Cerebrum,  the 
Cranio-Spinal  Axis  transmits  upwards  to  it  the  influence  of  Sensorial  changes, 
and  receives  from  it  the  downward  impulses,  which  it  directs  automatically  into 
the  appropriate  channel  for  the  execution  of  the  movements  which  the  Mind  has 
directed.     The  number  of  purely  automatic  actions  diminishes  in  proportion  to 
the  development  of  the  Cerebrum,  and  to  the  subjection  of  the  Automatic  ap- 
paratus to  its  control ;  but  even  in  Man,  those  most  closely  connected  with  the 
maintenance  of  the  organic  functions,  or  most  necessary  for  the  conservation  of 
the  bodily  structure,  remain  quite  independent  of  any  mental  agency,  and  most  of 
them  do  not  require  consciousness  for  their  excitation.     But  when  the  activity  of 
the  Cerebrum  is  suspended  or  is  otherwise  directed,  without  any  affection  of  the 
automatic  apparatus,  movements  which  have  long  been  habitually  performed  in 
a  particular  sequence,  may  be  kept  up,  when  the  will  has  once  set  them  in  action, 
through  the  automatic  mechanism  alone  ;  the  impressional  or  sensational  change 
produced  by  each  action  supplying  the  stimulus  which  calls  forth  the  next. — It 
may  further  be  concluded  that  the  Sensory  Ganglia,  which  are  the  instruments 
whereby  we  are  rendered  conscious  of  external  impressions,  are  also  the  seat  of 
those  simple  feelings  of  pleasure  and  pain  which  are  immediately  linked  on  to 
that  consciousness.     For  it  can  scarcely  be  doubted  that  such  feelings  must  be 
associated  with  particular  sensations,  in  animals  that  have  no  ganglionic  centres 
above  these ;  since  we  must  otherwise  regard  the  whole  series  of  Invertebrated 
tribes  as  neither  susceptible  of  enjoyment,  nor  capable  of  feeling  pain  or  dis- 
comfort.    And  it  is  scarcely  probable  that  a  state  of  consciousness  which  we  can 
scarcely  ourselves  distinguish  from  the  sensation  that  induces  it  should  have  a 
separate  centre  in  our  Encephalon. 

4. —  Of  the  Cerebellum,  and  its  Functions. 

760.  The  Cerebellum  is  an  organ  which,  though  confined  to  the  Vertebrated 
sub-Kingdom,  is  yet  in  peculiarly  intimate  relation  with  tHe  Automatic  appa- 
ratus.    In  that  highest  state  of  development  which  it  presents  in  Man,  we  find 
it  to  consist  of  two  lateral  lobes  or  hemispheres,  composed  of  nerve-fibres  invested 
in  a  very  peculiar  manner  by  vesicular  substance,  and  of  a  central  lobe,  also 
containing  a  combination  of  the  vesicular  and  fibrous  substances,  which  is  known 
under  the  designation  of  the  "  vermiform  process/'     The  hemispheres  are  not 
only  connected  with  each  other  by  this  central  lobe,  but  also  by  the  fibrous  com- 
missure which  passes  beneath  the  Medulla  Oblongata,  and  is  known  as  the 
"  Pons  Varolii."     The  commissural  fibres  form  part  of  the  "  Crura  Cerebelli ;" 
but  another  portion  is  formed  by  the  strands  which  connect  the  Cerebellum  with 


OF   THE   CEREBELLUM,    AND   ITS   FUNCTIONS.  729 

the  anterior  and  posterior  columns  of  the  Spinal  Cord  and  Medulla  Oblongata 
(§  711);  and  in  addition  to  these,  we  find  a  fasciculus  of  fibres  passing  between 
the  Cerebellum  and  the  Corpora  Quadrigemina,  the  "iter  a  cerebello  ad  testes." 
The  peduncle  of  its  hemispheres  on  either  side  contains  a  mass  of  gray  matter, 

Fig.  193. 


An  under  view  of  the  cerebellum,  seen  from  behind. — The  medulla  oblongata,  m,  having  been  cut  off  a 
short  way  below  the  pons.  (Reil.)  c.  Pons  Varolii.  d.  Middle  crus  of  cerebellum,  e  e.  Crura  cerebri.  i. 
Notch  on  posterior  border.  Jc.  Commencement  of  horizontal  fissure.  I.  Flocculus,  or  sub-peduncular  lobe. 
m.  Medulla  oblongata  cut  through,  q  to  s.  The  inferior  vermiform  process,  lying  in  the  vallecula.  p.  Pyramid. 
r.  Uvula,  n  n.  Amygdalae,  s.  Nodule,  or  laminated  tubercle,  x.  Posterior  velum,  partly  seen.  w.  Right  and 
left  hemispheres  of  cerebellum.  3  to  7.  Nerves.  33.  Motores  oculorum.  5.  Trigeminal.  6.  Abducent  nerve. 
7.  Facial  and  auditory  nerves. 

which  seems  to  be  a  ganglionic  centre  for  the  fibres  that  pass  upwards  to  it  from 
the  Spinal  Axis.  Thus  the  Cerebellum  has  no  direct  connection  with  the  Cere- 
brum, and  its  relations  are  entirely  with  the  Automatic  apparatus. 

761.  When  we  examine  into  the  relative  development  of  the  Cerebellum  in 
the  different  classes  of  Vertebrata,  we  find  that  it  presents  some  very  remarkable 
differences.1  In  its  simpler  forms,  this  organ  is  found  to  consist  entirely  of  the 
representative  of  the  central  lobe  of  the  Human  Cerebellum,  the  hemispheres 
not  making  their  appearance  until  we  have  ascended  to  the  class  of  Birds.  The 
proportional  development  of  the  Cerebellum  is  smallest  in  the  Vermiform  Fishes, 
which  approach  most  nearly  to  the  Invertebrata ;  but  it  is  much  greater  in 
the  higher  Cartilaginous  Fishes  than  it  is  in  Reptiles,  in  which  it  is  generally 
very  low.  Passing  on  to  Birds,  we  remark  that  the  average  dimensions  of  the 
Cerebellum  greatly  surpass  those  of  the  organ  in  Reptiles ;  but  that  they  do  not 
exceed  those  occasionally  met  with  in  Fishes.  The  greatest  size  is  not  found  in 
those  species  which  approach  most  nearly  to  the  Mammalia  in  general  con- 
formation, such  as  the  Ostrich ;  but  in  those  of  most  active  and  varied  powers 
of  flight.  Lastly,  on  ascending  the  scale  of  Mammiferous  animals,  we  cannot 
but  be  struck  with  the  rapid  advance  in  the  proportional  size  of  the  Cerebellum 
which  we  observe  as  we  rise  from  the  lowest  (which  are  surpassed  in  this  respect 
by  many  Birds)  towards  Man,  in  whom  it  attains  a  development  which  appears 
enormous,  even  when  contrasted  with  that  of  the  Quadrumana. — Now  on  looking 
at  the  size  of  the  Cerebellum  in  relation  to  the  general  motor  activity  of  these 
classes  respectively,  and  especially  taking  into  account  the  variety  of  their 
respective  movements,  and  the  number  of  separate  muscular  actions  which  are 
combined  in  each,  we  can  scarcely  help  noticing  that  it  is  in  the  tribes  which  are 
most  distinguished  in  these  respects,  that  the  largest  Cerebellum  is  usually  found. 

1  The  fullest  information  upon  this  point  will  be  found  in  M.  Serres's  "Anatomic 
Comparee  du  Cerveau,"  and  M.  Leuret's  "  Anat.  Comp.  du  Systeme  Nerveux." 


730 


OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 


Thus,  of  all  classes  of  Vertebrata,  Reptiles  are  the  most  inert ;  and  their  motions 
require  the  least  co-ordination.  The  active  predaceous  Sharks  far  surpass  them 
in  this  respect,  and  may  be  compared  with  Birds,  in  the  energy  of  their  passage 
through  the  water,  and  in  their  facility  of  changing  their  direction  during  the 
most  rapid  progression;  their  Cerebellum,  accordingly,  bears  to  their  Spinal 
Cord  very  much  the  same  proportion  as  it  does  in  Birds.  On  the  other  hand, 
the  Flat  Fish,  which  lie  near  the  bottom  of  the  ocean,  and  which  have  a  much 
less  variety  of  movement,  have  a  very  much  smaller  Cerebellum;  and  the 
Vermiform  Fishes,  which  are  almost  all  completely  destitute  of  fins,  and  whose 

Fig.  194. 


Analytical  diagram  of  the  Encephalon— in  a  vertical  section.  (After  Mayo.)— s.  Spinal  Cord.  r.  Restiform 
bodies  passing  to  c,  the  cerebellum,  d.  Corpus  dentatum  of  the  cerebellum,  o.  Olivary  body.  /.  Column? 
continuous  with  the  olivary  bodies  and  central  part  of  the  medulla  oblongata,  and  ascending  to  the  tubercula 
quadrigemina  and  optic  thalami.  p.  Anterior  pyramids,  v.  Pons  Varolii.  n,  b.  Tubercula  quadrigemina. 
g.  Geniculate  body  of  the  optic  thalamus.  t.  Processus  cerebelli  ad  testes.  a.  Anterior  lobe  of  the  brain. 
g.  Posterior  lobe  of  the  brain. 

motions  resemble  those  of  the  lower  Articulata,  have  a  Cerebellum  so  small  as 
to  be  scarcely  discoverable.  On  looking  at  the  class  of  Birds,  we  observe  that 
the  active  predaceous  Falcons,  and  the  swift-winged  Swallows  (the  perfect  control 
possessed  by  which  over  their  complicated  movements  must  have  been  observed 
by  every  one),  have  a  Cerebellum  much  larger  in  proportion  than  that  of  the 


OF   THE   CEREBELLUM,   AND   ITS   FUNCTIONS. 


731 


Gallinaceous  birds,  whose  powers  of  flight  are  small,  or  than  that  of  the  Struthious 
tribe,  in  which  they  are  altogether  absent.  Lastly,  on  comparing  its  proportional 
size  in  the  different  orders  of  mammalia,  with  the  number  and  variety  of  muscular 
actions  requiring  combined  movements,  of  which  they  are  respectively  capable, 

[Fig.  194*. 


This  figure  exhibits  those  fibres  from  the  anterior  columns  which,  ascending  to  the  cerebellum,  con- 
nect the  motor  tract  with  that  portion  of  the  cerebral  mass.  E.  Cerebellum,  x.  Pons  Varolii.  T.  Pyra- 
midal eminences,  s.  Olivary  bodies,  w  w.  Corpus  restiforme,  its  surface  having  been  carefully  scraped,  in 
order  to  show  the  superficial  cerebellar  fibres  of  the  anterior  columns.  They  are  represented  rather  more 
distinct  and  thick  than  they  really  appear,  though  their  course,  direction,  and  relation  to  the  olivary  body 
are  faithfully  given.— ED.] 

we  observe  an  even  more  remarkable  correspondence.  In  the  hoofed  Quadru- 
peds, in  which  the  muscular  apparatus  of  the  extremities  is  reduced  to  its  greatest 
simplicity,  and  in  which  the  movements  of  progression  are  simple,  the  Cere- 
bellum is  relatively  smaller  than  it  is  found  to  be  in  some  Birds ;  but  in  pro- 
portion as  the  extremities  acquire  the  power  of  prehension,  and  together  with 
this  a  power  of  application  to  a  great  variety  of  purposes — still  more,  in  propor- 
tion as  the  animal  becomes  capable  of  maintaining  the  erect  posture,  in  which  a 
constant  muscular  exertion,  consisting  of  a  number  of  most  elaborately  combined 
actions,  is  required — do  we  find  the  size  of  the  Cerebellum,  and  the  complexity 
of  its  structure,  undergoing  a  rapid  increase.  Thus,  even  between  the  Dog  and 
the  Bear  there  is  a  marked  difference ;  the  latter  being  capable  of  remaining  for 
some  time  in  the  erect  posture,  and  often  spontaneously  assuming  it ;  whilst  to 


732  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

the  former  it  is  anything  but  natural.  In  the  semi-erect  Apes,  again,  there  is 
a  very  great  advance  in  the  proportional  size  of  the  Cerebellum ;  and  those 
Vhich  most  approach  Man  in  the  tendency  to  preserve  habitually  the  erect 
posture,  also  come  nearest  to  him  in  the  dimensions  of  this  organ. 

762.  Now  it  is  evident  that  Man,  although  far  inferior  to  many  of  the  lower 
animals  in  the  power  of  performing  various  particular  kinds  of  movement,  far 
surpasses  them  all  in  the  number  and  variety  of  the  combinations  which  he  is 
capable  of  executing,  and  in  the  complexity  of  the  combinations  themselves. 
Thus,  if  we  attentively  consider  the  act  of  walking  in  man,  we  shall  find  that 
there  is  scarcely  a  muscle  of  the  trunk  or  extremities  which  is  not  actively 
concerned  in  it ;  some  being  engaged  in  performing  the  necessary  movements, 
and  others  in  maintaining  the  equilibrium  of  the  body,  which  is  disturbed  by 
them.     On  the  other  hand,  in  the  Horse  or  Camel,  the  muscular  movements 
are  individually  numerous,  but  they  do  not  require  nearly  the  same  perfect  co- 
ordination.    And  in  the  Bird,  the  number  of  muscles  employed  in  the  move- 
ments of  flight,  and  in  directing  the  course  of  these,  is  really  comparatively 
small ;  as  may  at  once  be  perceived,  by  comparing  the  rigidity  of  the  skeleton 
of  the  trunk  of  the  Bird  with  that  of  Man,  and  by  remembering  the  complete 
inactivity  of  the  lower  extremities  during  the  active  condition  of  the  upper.     In 
fact,  the  motions  of  the  wings  are  so  simple  and  regular  as  to  suggest  the  idea 
that,  as  in  Insects,  their  character  is  more  automatic  than  directly  voluntary — 
an  idea  which  is  supported  by  the  length  of  time  during  which  they  can  be  kept 
up  without  apparent  fatigue,  and  also  by  the  important  facts  already  mentioned, 
which  experimental  research  has  disclosed  (§  734). 

763.  We  have  next  to  inquire  what  evidence  can  be  drawn  from  Experimental 
investigations  on  the  same  subject :  and  in  reference  to  this  it  is  desirable  to 
remark,  in  the  first  place,  that  the  experimental  mode  of  inquiry  is  perhaps  more 
applicable  to  this  organ  than  to  other  parts  of  the  Encephalon ;  inasmuch  as  it  can 
be  altogether  removed,  with  little  disturbance  of  the  actions  immediately  essen- 
tial to  life ;  and  the  animals  soon  recover  from  the  shock  of  the  operation,  and 
seem  but  little  affected,  except  in  some  easily  recognized  particulars.     The  prin- 
cipal experimenters  upon  this  subject  have  been  llolando,  Flourens,  Magendie, 
Hertwig,  and  Longet.     It  is  not  to  be  expected  that  there  should  be  an  exact 
conformity  among  the  results  obtained  by  all.     Every  one  who  has  been  en- 
gaged in  physiological  experiments  is  aware  of  the  amount  of  difference  caused 
by  very  minute  variations  in  their  circumstances ;  in  no  department  of  inquiry 
is  this  more  the  case  than  in  regard  to  the  Nervous  System ;  and  such  differ- 
ences are  yet  more  likely  to  occur  in  experiments  made  upon  its  centres  than 
in  those  which  concern  its  trunks. — The  investigations  of  Flourens  are  the 
most  clear  and  decisive  in  their  results ;  and  of  these  we  shall  accordingly  take 
a  general  survey.     He  found  that,  when  the  Cerebellum  was  mechanically  in- 
jured, the   animals  gave  no  signs  of  sensibility,  nor  were  they  affected   with 
convulsions.     When  the  Cerebellum  was  being  removed  by  successive  slices, 
the  animals  became  restless,  and  their  movements  were  irregular ;  and  by  the 
time  that  the  last  portion  of  the  organ  was  cut  away,  the  animals  had  entirely 
lost  the  power  of  springing,  flying,  walking,  standing,  and  preserving  their 
equilibrium, — in  short,  of  performing  any  combined  muscular  movements  which 
are  not  of  a  simply  reflex  character.     When  an  animal  in  this  state  was  laid 
upon  the  back,  it  could  not  recover  its  former  posture ;  but  it  fluttered  its  wings, 
and  did  not  lie  in  a  state  of  stupor.     When  placed  in  the  erect  position,  it 
staggered  and  fell  like  a  drunken  man — not,  however,  without  making  efforts 
to  maintain  its  balance.     When  threatened  with  a  blow,  it  evidently  saw  it,  and 
endeavored  to  avoid  it.     It   did  not  seem  that  the  animal  had  in  any  degree 
lost  voluntary  power  over  its  several  muscles ;  nor  did  sensation  appear  to  be 
impaired.     The  faculty  of  combining  the  actions  of  the  muscles  in  groups, 


OF   THE   CEREBELLUM,    AND   ITS   FUNCTIONS.  733 

however,  was  completely  destroyed ;  except  so  far  as  those  actions  (as  that  of 
Respiration)  were  dependent  only  upon  the  reflex  function  of  the  Spinal  Cord. 
The  experiments  afforded  the  same  results,  when  made  upon  each  class  of  Ver-' 
tebrated  animals  ;  and  they  have  since  heen  repeated,  with  corresponding  effects, 
by  Bouillaud  and  Hertwig.  The  latter  agrees  with  Mourens,  also,  in  stating 
that  the  removal  of  one  side  of  the  Cerebellum  affects  the  movements  of  the 
opposite  side  of  the  body ;  and  he  further  mentions  that,  if  the  mutilation  of 
the  Cerebellum  have  been  partial  only,  its  function  is  in  great  degree  restored.1 

764.  It  was  further  affirmed  by  Magendie,  that  the  removal  of  the  Cere- 
bellum, or  the  infliction  of  a  deep  wound  of  its  substance  on  both  sides,  occa- 
sions the  animal  to  move  backwards  as  if  by  an  irresistible  impulse  j  and  this 
he  attributed  to  the  retrograde  power  of  the  Corpora  Striata,  which  now  acts 
without  its  due  balance.     That  such  a  movement  does  sometimes  present  itself 
after  such  injuries  as  have  been  described  cannot  be  questioned,  th$  fact  having 
been  confirmed  by  other  experimenters ;  but  it  is  a  phenomenon  of  such  rarity, 
that  it  cannot  be  rightly  considered  as  having  any  direct  dependence  upon  the 
injury  of  the  Cerebellum,  but  must  be  rather  set  down  to  some  accidental  com- 
plication or  concurrent  disturbance ;  more  especially  since,  as  already  pointed 
out  (  §  737),  the  function  attributed  by  Magendie  to  the  Corpora  Striata  has  no 
real  existence. — But  the  results  of  section  of  one  of  the  Crura  Cerebelli,  which 
were  first  obtained  by  Magendie,  are  much  more  constant ;  for  the  performance 
of  this  operation  causes  the  animal  to  fall  over  upon  one  side,  and  to  continue 
rolling  upon  its  longitudinal  axis,  even  as  fast  (in  some  instances)  as  sixty  times 
in  a  minute,  the  movement  going  on  for  many  days  without  intermission.     There 
is  a  remarkable  difference  in  the  statements  of  different  experimenters,  however, 
as  regards  the  direction  of  this  rolling  movement  ;  for,  whilst  Magendie  and 
Miiller  affirm  that  it  takes  place  towards  the  injured  side,  Longet  and  Lafargue 
assert  that  it  takes  place  from  the  injured  side  towards  the  opposite  side.     This 
discrepancy  appears,  from  the  experiments  of  Schiff,2  to  be  due  to  a  difference 
in  the  locality  of  the  section  ;  for  he  states  that  if  the  peduncle  be  divided  from 
behind,  the  animal  turns  towards  the  side  on  which  the  section  is  made ;  whilst 
if  the  section  be  made  in  front,  the   animal  turns  from  that  side  towards  the 
opposite  one.     This  difference  is  explained  by  Longet,  by  the  difference  in  the 
course  of  the  anterior  and  posterior  fibres  of  the  peduncles ;  for  according  to 
him  the  former  communicate  with  the  decussating,  and  the  latter  with  the  non- 
decussating  portion  of  the  motor  tract ;  so  that,  when  the  former  are  injured, 
the  animal  loses  control  over  the  muscles  of  the  opposite  side,  and  when   the 
latter,  over  the  muscles  of  the  same  side.     This  rolling  movement  is  attributed 
by  some  to  the  continued  activity  of  the  muscles  of  one  side,  now  unbalanced 
by  that  of  the  muscles  on  the  other ;  but  if  such  were  the  case,  as  Longet 
justly  remarks,  it  ought  to  occur  more  frequently  than  it  does  in  cases  of  ordi- 
nary hemiplegia ;  and  according  to  that  experimenter,  observation  shows  that 
it  rather  depends  on  a  twisting  movement  of  the  spinal  column,  especially  affect- 
ing its  anterior  portion,  and  dragging  the  posterior  (as  it  were)  after  it.3 

765.  The  information  supplied  by  Pathological  phenomena,  when  interpreted 
with  the  cautions  formerly  referred  to,  is  found  on  the  whole  to  coincide  with 

1  All  these  results  are  objected  to  by  those  who  assert  that  the  Cerebellum  is  the  seat  of 
the  sexual  instinct,  on  the  ground  that  the  observed  aberrations  of  the  motor  functions  are 
sufficiently  accounted  for  by  the  general  disturbance  which  an  operation  so  severe  must 
necessarily  induce.     The  fallacy  of  this  objection,  however,  is  shown  by  the  fact  that 
the  much  more  severe  operation  of  removing  the  Hemispheres  does  not  occasion  such  an 
aberration  ;  the  power  of  performing  the  associated  movements,  and  of  maintaining  the 
equilibrium,  being  remarkably  preserved  after  the  loss  of  them  ($  734). 

2  "  De  vi  motoria  baseos  encephali  inquisitiones  experimentales;"  Bockenhemii,  1845. 

3  See  his  "  Traite  de  Physiologic,"  torn.  ii.  partie  2,  pp.  216,  217. 


734  OF   THE   FUNCTIONS    OF   THE    NERVOUS    SYSTEM. 

that  obtained  from  experiment.  In  the  first  place,  it  fully  supports  the  con- 
clusion that  the  Cerebellum  is  not  in  any  way  the  instrument  of  psychical  opera- 
tions. Inflammation  of  the  membranes  covering  it,  if  confined  to  that  part, 
does  not  produce  delirium  ;  and  its  almost  complete  destruction  by  gradual 
softening  does  not  appear  necessarily  to  involve  loss  of  intellectual  power.  "But," 
remarks  Andral,  "  whilst  the  changes  of  intelligence  were  variable,  inconstant, 
and  of  little  importance,  the  lesions  of  motion,  on  the  contrary,  were  observed  in 
all  the  cases  [of  softening]  except  one  ;  and  in  this  it  is  not  quite  certain  that 
motion  was  not  interfered  with."  Yet  the  result  of  Andral's  analysis  of  as 
many  as  ninety-three  cases  of  disease  of  the  Cerebellum,1  is  not  favorable  to 
the  doctrine  to  which  the  results  of  experiments  seem  to  point;  but,  as  it  has 
been  justly  remarked  by  Longet,  the  effects  of  disease  are  only  partly  compar- 
able to  those  of  experiment;  since  in  a  large  proportion  of  chronic  cases  of 
the  former,  the  change  consists  in  the  formation  of  a  new  product,  such  as  a 
tubercular  or  cancerous  deposit,  or  a  cyst  of  some  kind,  the  gradual  develop- 
ment of  which  is  quite  consistent  with  the  continued  functional  activity  of  the 
organ,  as  we  see  by  parallel  phenomena  elsewhere ;  whilst  in  those  instances  in 
which  hemorrhage  occurs,  this  usually  occasions  either  complete  apoplexy  or 
local  paralysis,  by  its  effects  upon  other  organs.  Still,  several  cases  of  chro- 
nic disease  of  the  Cerebellum  have  been  observed  in  which  unsteadiness  of  gait, 
without  paralysis,  or  only  giving  place  to  paralysis  at  last  on  the  occurrence  of 
hemorrhage,  was  a  very  marked  symptom  ;a  and  these  afford  a  strong  confirm- 
ation of  the  doctrine  based  on  the  experimental  researches  already  referred  to.  In 
a  few  cases  in  which  both  lobes  of  the  Cerebellum  have  been  seriously  affect- 
ed, the  tendency  to  retrograde  movement  has  been  observed ;  and  instances  are 
also  on  record,  of  the  occurrence  of  rotary  movement,  which  has  been  found 
to  be  connected  with  lesion  of  the  Crus  Cerebelli  on  the  same  side.3  So  far  as 
they  can  be  relied  on,  therefore,  the  results  of  the  three  methods  of  investigation 
bear  a  very  close  correspondence ;  and  it  can  scarcely  be  doubted  that  they  afford 
us  a  near  approximation  to  truth. 

766.  It  must  not  be  allowed  to  pass  unnoticed,  that  some  Physiologists  (as 
Foville,  Pinel-Grandchamp,  and  Duges)  have  regarded  the  Cerebellum  as  the 
centre  of  common  Sensation ;  chiefly  on  the  ground  of  its  connection  with  the 
posterior  columns  of  the  Spinal  Cord,  and  of  the  manifestations  of  pain  which 
are  called  forth  by  touching  the  Restiform  columns.  Although  these  facts  may 
lead  us  to  admit  that  the  Cerebellum  is  connected  with  the  sensorial  centres, 
and  even  that  it  is  itself  a  seat  of  sensibility,  yet  it  is  impossible  to  regard  it  as 
the  exclusive  seat  of  sensibility,  consistently  with  the  facts  with  which  experi- 
ment and  pathological  observation  supply  us ;  since  neither  the  complete  removal 
of  this  organ  by  operation,  nor  its  complete  destruction  by  disease,4  has  been 
found  to  involve  any  loss  of  the  ordinary  sensorial  powers. — There  would  seem 
much  more  probability  in  the  idea  that  it  is  the  special  seat  of  the  "  muscular 
sense,"  which  has  so  important  a  share  in  the  guidance  of  the  co-ordinated  move- 

1  See  his  "  Clinique  Me'dicale,"  2eme  edit.  torn.  v.  p.  735. 

2  Two  such  cases  are  recorded  by  Mr.  Dunn  in  the  "  Med.-Chir.  Trans.,"  vol.  xxxii., 
and  another  by  Dr.  Cowan  in  the  "  Prov.  Med.  and  Surg.  Journ.,"  April  16,   1845;  and 
the  Author  has  been  made  acquainted  with  several  others,  by  gentlemen  under  whose  cog- 
nizance they  have  fallen. 

3  A  collection  of  such  cases  has  been  made  by  Dr.   Paget,  in  his  paper  on  "  Morbid 
Rhythmical  Movements/'  in  the  "  Edinb.  Med.  and  Surg.  Journal,"  1847,  vol.  Ixvii. — A 
case  fell  within  the  Author's  knowledge  a  few  years  ago,  in  which  a  state  of  this  kind, 
that  lasted  for  some  hours,  appeared  to  depend  upon  an  attack  of  indigestion ;  the  symp- 
toms being  completely  relieved  by  vomiting,  and  no  further  indication  of  encephalic  dis- 
order manifesting  itself. 

4  See  the  well-known  case  recorded  by  Combetti,  in  the  "Revue  Me'dicale,"   torn.  ii. 
p.  57 


OF   THE   CEREBELLUM,   AND   ITS   FUNCTIONS.  735 

ments ;  and  this  notion  derives  confirmation  from  the  marked  structural  con- 
nection which  exists  between  the  Cerebellum  and  the  Optic  Ganglia  (corpora 
quadrigemina),  the  purpose  of  which  maybe  not  unfairly  surmised  to  be,  to  commu- 
nicate the  guidance  of  the  visual  sense  to  the  organ  by  which  the  co-ordina- 
tion of  motions  is  effected,  in  the  same  manner  as  the  impressions  appertaining 
to  the  muscular  sense  are  transmitted  upwards  by  the  Restiform  columns.  The 
chief  objection  to  such  a  view  would  seem  to  lie  in  the  strong  similarity  between 
the  "  muscular"  sense  and  "  common"  or  "  tactile"  sensation,  which  makes  it  diffi- 
cult to  conceive  that  they  should  have  different  seats  in  the  Sensorium  commune. 
But  this  difficulty  is  diminished  if  not  removed  by  the  reflection,  that  the  Resti- 
form  columns  appear  to  have  the  same  endowments  as  the  remainder  of  the  Sen- 
sory tract  derived  from  the  posterior  columns  of  the  Spinal  Cord  :  and  that  no 
explanation  can  be  given  of  their  extreme  sensitiveness  to  impressions  (as  shown 
by  experiment),  unless  it  be  admitted  that  the  organ  in  which  they  terminate 
is  itself  a  centre  of  a  form  of  sensation  closely  allied  to  that  of  the  common  or 
tactile  kind.  Possibly,  however,  the  true  termination  of  these  fibres  is  in  the 
"  corpus  dentatum"  of  the  Crura  Cerebelli ;  and  the  Cerebellum  may  only  react 
upon  impressions  thence  transmitted  to  it,  without  being  itself  the  instrument 
of  communicating  such  impressions  to  the  consciousness. 

767.  We  have  now  to  examine,  however,  another  doctrine  regarding  the  functions 
of  the  Cerebellum,  which  was  first  propounded  by  Gall,  and  which  is  supported 
by  the  Phrenological  school  of  physiologists.  This  doctrine,  that  the  Cerebellum 
is  the  organ  of  the  sexual  instinct,  is  not  altogether  incompatible  with  the  other; 
and  by  some  it  has  been  held  in  combination  with  it.  The  greater  number  of 
Phrenologists,  however,  regard  this  instinct  as  the  exclusive  function  of  the 
Cerebellum ;  and  assert  that  they  can  judge  of  its  intensity  by  the  degree  of 
development  of  the  organ.  We  shall  now  examine  the  evidence  in  support 
of  this  position,  afforded  by  the  three  methods  of  inquiry  which  have  been  al- 
ready indicated.  In  the  first  place,  it  may  be  remarked  that  the  sexual  propen- 
sity is  very  closely  connected  with  various  emotional  states  of  mind  to  which 
"  organs"  are  assigned  by  Phrenologists,  and  of  which  the  Cerebrum  is  univer- 
sally admitted  to  be  the  seat ;  such,  for  instance,  as  "  love  of  offspring/'  "  ad- 
hesiveness," and  in  the  lower  animals  more  particularly  with  "  combativeness ;" 
and  in  Man  it  has  a  continual  operation  upon  the  reasoning  faculties  and  the 
Will.  Yet  the  anatomical  connections  of  the  Cerebellum  are  peculiarly  unfa- 
vorable to  any  such  influence ;  these  being,  as  we  have  seen,  rather  with  the 
lower  than  with  the  higher  portion  of  the  Cerebro-spinal  axis. — Again,  the  re- 
sults of  fair  observation  as  to  the  comparative  size  of  the  Cerebellum  in  differ- 
ent animals  can  scarcely  be  regarded  as  otherwise  than  very  unfavorable  to 
the  doctrine  in  question.  In  the  greater  number  of  Fishes,  it  is  well  known 
that  no  sexual  congress  takes  place ;  the  seminal  fluid  being  merely  effused,  like 
any  other  excretion,  into  the  surrounding  water ;  and  being  thus  brought  into 
only  accidental  contact  with  the  ova,  of  which  a  large  proportion  are  never  fer- 
tilized. But  there  are  certain  Fishes,  as  the  Sharks,  Rays,  and  Eels,  in  which 
copulation  takes  place  after  the  ordinary  method.  Now  on  contrasting  these 
groups,  we  find  no  corresponding  difference  in  the  size  of  the  Cerebellum.  It  is 
true  that  this  organ  is  of  large  size  in  the  Sharks  ;  but  it  is  smaller  in  the  Rays, 
and  almost  rudimentary  in  the  Eels ;  in  this  respect  bearing  a  precise  corre- 
spondence with  the  variety  and  complexity  of  their  movements.  Further,  in 
many  ordinary  Fishes,  which  do  not  copulate,  such  as  the  Cod,  the  Cerebellum 
is  not  only  larger,  but  more  complex  in  structure,  than  it  is  in  the  generality  of 
Reptiles,  in  which  the  sexual  instinct  is  commonly  strong ;  the  whole  spinal 
system  of  the  Frog  possessing,  at  the  season  of  reproduction,  an  extraordinary 
degree  of  excitability,  which  is  evidently  destined  to  aid  in  the  performance  of 
the  function.  Again,  on  comparing  the  Gallinaceous  Birds,  which  are  poly- 


736 


OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 


gamous  with  the  Raptorial  and  Insessorial  tribes  which  live  in  pairs,  we  find 
that  the  former,  instead  of  having  a  larger  Cerebellum,  have  one  of  inferior  size. 
Further,  on  looking  at  the  Mammalia,  the  same  disproportion  may  be  noticed. 
A  friend  who  kept  some  Kangaroos  in  his  garden  informed  the  author  that  they 
were  the  most  salacious  animals  he  ever  saw ;  yet  their  Cerebellum  is  one  of  the 
smallest  to  be  found  in  the  class.  Every  one  knows,  again,  the  salacity  of  Mon- 
keys ;  there  are  many  which  are  excited  to  violent  demonstrations  by  the  sight 
even  of  a  human  female ;  and  there  are  few  which  do  not  practise  masturbation, 
when  kept  in  solitary  confinement ;  yet  in  them  the  Cerebellum  is  much  smaller 
than  in  Man,  in  whom  the  sexual  impulse  is  much  less  violent.  It  has  been 
supposed  that  the  large  size  of  the  organ  in  Man  is  connected  with  his  constant 
possession  of  the  appetite,  which  is  only  occasional  in  others ;  but  this  does  not 
hold  good,  since  among  domestic  animals  there  are  many  which  are  ready  to 
breed  throughout  the  year,  Cats  and  Rabbits,  for  instance,  and  in  these  we  do 
not  find  any  peculiar  difference  in  the  size  of  the  Cerebellum.1 

768.  It  is  asserted,  however,  that  the  results  of  observation  in  Man  lead  to  a 
positive  conclusion  that  the  size  of  the  Cerebellum  is  a  measure  of  the  intensity 
of  the  sexual  instinct  in  the  individual.  This  assertion  has  been  met  by  the 
counter-statement  of  others  that  no  such  relation  exists.  It  is  unfortunate  that 
here,  as  in  many  other  instances,  each  party  has  registered  the  observations  fa- 
vorable to  its  own  views,  rather  than  those  of  an  opposite  character ;  so  that 
until  some  additional  evidence  of  a  less  partial  nature  shall  have  been  collected, 
we  must  consider  the  question  as  sub  judice.  It  may  be  safely  affirmed,  how- 
ever, that  no  evidence  upon  the  affirmative  side  of  this  proposition  has  yet  been 
adduced,  which  can  be  in  the  least  degree  satisfactory  to  the  mind  of  any  Ana- 
tomist who  is  competent  to  judge  of  its  value.  For  nearly  all  the  observations 
which  have  been  paraded  by  Phrenologists  in  support  of  Gall's  doctrine  have 
been  based,  not  upon  the  actual  determination  of  the  size  or  weight  of  the  Cere- 
bellum in  different  individuals,  but  upon  the  estimation  of  its  proportional 
development  from  the  external  conformation  of  the  skull.  Now  any  one  who 
has  even  cursorily  examined  those  principal  types  of  cranial  conformation  which 
are  characteristic  of  some  of  the  chief  subdivisions  of  the  Human  species,  must 
perceive  that  there  is  a  no  less  characteristic  difference  between  these  different 
types  in  the  occipital,  than  there  is  in  the  frontal  region.  For  whilst  the  occi- 
pital projection  is  much  greater  in  the  "  prognathous"  skull  than  it  is  in  the 
"elliptical,"  it  is  as  much  less  in  the  " pyramidal;"  and  thus  while  the  first 
would  be  considered,  according  to  phrenological  rules,  to  hold  a  much  larger 
Cerebellum,  this  organ  in  the  latter  would  be  regarded  as  necessarily  very  small. 
Now  there  is  not  only  as  much  evidence  of  a  strong  development  of  the  sexual 
propensity,  in  the  characters  and  habits  of  the  pyramidal-skulled  Asiatics,  as 
there  is  in  regard  to  the  elliptical-skulled  Europeans,  or  the  prognathous  Negroes  ; 
but  there  is  also  anatomical  evidence  to  show  that  the  size  of  the  Cerebellum  in 
the  different  races  bears  no  relation  whatever  to  the  degree  of  projection  of  the 
occiput ;  for  the  plane  of  this  organ,  being  somewhat  oblique  in  the  elliptical 
skull,  is  horizontal  in  the  prognathous,  and  nearly  vertical  in  the  pyramidal, 
while  the  size  and  anatomical  relations  of  the  organ  are  not  in  the  least  degree 
affected  by  this  difference  in  its  position.3 — Hence  it  may  be  safely  affirmed, 
that  no  evidence  with  regard  to  the  relation  asserted  to  exist  between  the  size 
of  the  Cerebellum  and  the  intensity  of  the  Sexual  propensity,  has  any  value, 
save  that  which  is  drawn  from  the  positive  determination  of  the  former  by 
measure  or  weight. 

1  For  a  fuller  examination  of  the  indications  afforded  by  Comparative  Anatomy  in  re- 
gard to  this  question,  sec  the  "Brit,  and  For.  Medical  Review,"  Oct.,  1846,  pp.  534. 

2  The  author's  statements  on  this  point  are  based  on  the  very  decided  assertions  of  his 
friend,  Prof.  Retzius,  of  Stockholm,  who  has  paid  special  attention  to  this  inquiry. 


OF   THE   CEREBELLUM,    AND   ITS   FUNCTIONS.  737 

769.  Among  the  arguments  adduced  by  Gall  and  his  followers  in  proof  of  the 
connection  between  the  Cerebellum  and  the  sexual  instinct,  is  one  which  would 
deserve  great  attention,  if  the  facts  stated  could  be  relied  on.  It  has  been  as- 
serted, over  and  over  again,  that  the  Cerebellum,  in  animals  which  have  been 
castrated  when  young,  is  much  smaller  than  in  those  which  have  retained  their 
virility — being,  in  fact,  atrophied  from  want  of  power  to  act.  Now  it  is  unfor- 
tunate that  vague  assertion,  founded  on  estimates  formed  by  the  eye  from  the 
cranium  alone,  is  all  on  which  this  position  rests  ;  and  it  will  be  presently  shown 
how  very  liable  to  error  such  an  estimate  must  be.  The  following  is  the  result 
of  a  series  of  observations  on  this  subject,  suggested  by  M.  Leuret,1  and  car- 
ried into  effect  by  M.  Lassaigne  :  The  weight  of  the  Cerebellum,  both  abso- 
lutely, and  as  compared  with  that  of  the  Cerebrum,  was  adopted  as  the  standard 
of  comparison.  This  was  ascertained  in  ten  Stallions,  of  the  ages  of  from 
nin3  to  seventeen  years  ;  in  twelve  Mares,  aged  from  seven  to  sixteen  years; 
snd  in  twenty-one  Geldings,  aged  from  seven  to  seventeen  years.  The  average 
weight  of  the  Cerebrum  in  the  Stallions  was  433  grammes  ;  the  greatest  being 
485  gr.,  and  the  least  (which  was  in  a  horse  of  ten  years  old)  being  350  gr. 
The  average  weight  of  the  Cerebellum  was  61  gr. ;  the  greatest  being  65  gr., 
and  the  least  56  gr.  The  average  proportion  borne  by  the  weight  of  the  Cere- 
bellum to  that  of  the  Cerebrum  was,  therefore,  1  to  7.07 ;  the  highest  (result- 
ing from  a  very  small  Cerebrum)  being  1  to  6.25 ;  and  the  lowest  (resulting 
from  an  unusually  large  Cerebrum)  being  1  to  7.46.  Throughout  it  might  be 
observed  that  the  variation  in  the  size  of  the  Cerebellum  was  much  less  than 
in  that  of  the  Cerebrum. — In  the  twelve  Mares,  the  average  weight  of  the 
Cerebrum  was  402  gr. ;  the  highest  being  432  gr.,  and  the  lowest  363  gr. 
That  of  the  Cerebellum  was  61  gr. ;  the  highest  being  66  gr.  (which  was  in  the 
individual  with  the  smallest  Cerebrum),  and  the  lowest  58  gr.  The  average 
proportion  of  the  weight  of  the  Cerebellum  to  that  of  the  Cerebrum  was  1  to 
6.59 ;  the  highest  being  1  to  5.09,  and  the  lowest  1  to  7.  The  proportion  was, 
therefore,  considerably  higher  in  the  perfect  female  than  in  the  perfect  male. — 
In  the  twenty-one  Geldings,  the  average  weight  of  the  Cerebrum  was  419  gr.  j 
the  highest  being  566  gr.,  and  the  lowest  346  gr.  The  average  of  the  Cere- 
bellum was  70  gr. ;  the  highest  being  76  gr.,  and  the  lowest  64  gr.  The  ave- 
rage proportion  was,  therefore,  1  to  5.97 ;  the  highest  being  1  to  5.16,  and  the 
lowest  1  to  7.44.  It  is  curious  that  this  last  was  in  the  individual  which  had 
the  largest  Cerebellum  of  the  whole ;  but  the  proportional  weight  of  the  Cere- 
brum was  still  greater. — Bringing  together  the  results  of  these  observations, 
they  are  found  to  be  quite  opposed  to  the  statement  of  Gall.  The  weight  of 
the  Cerebrum,  reckoning  the  Cerebellum  as  1,  is  thus  expressed  in  each  of 
the  foregoing  descriptions  of  animals : — 

Average.  Highest.  Lowest. 

Stallions 7.07  7.46  6.25 

Mares 6.59  7.00  5.09 

Geldings 5.97  7.44  5.16 

The  average  proportional  size  of  the  Cerebellum  in  Geldings,  therefore,  is  so 
far  from  being  less  than  that  which  it  bears  in  entire  Horses  and  Mares,  that  it 
is  positively  greater;  and  this  depends  not  only  on  diminution  in  the  relative 
size  of  the  Cerebrum,  but  on  its  own  larger  dimension,  as  the  following  com- 
parison of  absolute  weights  will  show : — 

Average.  Highest.  Lowest. 

Stallions       '-';..         .         .         .         61  65  56 

Mares      .         .         .  -      .         .     '    .         61  66  58 

Geldings          *    '     ;        ...        70  76  64 


1  "Anat.  Comp.  du  SystemeNerveux,"  torn.  i.  p.  427. 

47 


738  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

The  difference  is  so  remarkable,  and  appears,  from  examination  of  the  individual 
results,  to  be  so  constant,  that  it  cannot  be  attributed  to  any  accidental  circum- 
stance arising  out  of  the  small  number  of  animals  experimented  on.  The  average 
weight  of  the  Cerebellum  in  the  ten  Stallions  and  twelve  Mares  is  seen  to  be 
the  same,  and  the  extremes  differ  but  little  in  the  two ;  whilst  the  average  in 
the  Geldings  is  more  than  one-seventh  higher,  and  the  lowest  is  considerable 
above  the  average  of  the  preceding,  while  the  highest  far  exceeds  the  highest 
among  the  entire  Horses.  It  is  curious  that  Gall  would  have  been  much  nearer 
the  truth,  if  he  had  said  that  the  dimensions  of  the  Cerebrum  are  usually  re- 
duced by  castration ;  for  it  appears  from  the  following  table  that  such  is  really 
the  case : — 

Average.  Greatest.  Least. 

Stallions 433  485  350 

Mares 402  432  336 

Geldings 419  566  346 

The  weight  of  the  largest  Cerebrum  of  the  Gelding  is  far  above  the  highest  of 
the  Stallions ;  but  it  seems  to  be  an  extraordinary  case,  as  in  no  other  was  the 
weight  above  490  gr.  If  this  one  be  excluded,  the  average  will  be  reduced 
still  further,  being  then  about  412  ;  this  may  be  seen,  by  looking  over  the 
whole  table,  to  give  a  very  fair  idea  of  the  usual  weight  in  these  animals,  which 
is  therefore  less,  by  about  one-twentieth,  than  the  average  in  the  Stallions. — 
The  increased  size  of  the  Cerebellum  in  Geldings  may  perhaps  be  accounted  for 
by  remembering  that  this  class  of  horses  is  solely  employed  for  its  muscular 
power,  and  that  the  constant  exercise  of  the  organ  is  not  unlikely  to  develop 
its  size  ;  whilst  Stallions,  being  kept  especially  for  the  purpose  of  propagation, 
are  much  less  applied  to  occupations  which  call  forth  their  motor  faculties. 

770.  It  is  asserted,  however,  by  the,  followers  of  Gall,  that  very  strong  evi- 
dence of  the  truth  of  his  doctrine  is  afforded  by  Pathological  phenomena;  ex- 
citement of  the  genital  organs,  manifesting  itself  in  priapism,  turgescence  of  the 
testes,  and  seminal  emissions,  being  an  ordinary  concomitant  of  some  forms  of 
apoplexy  in  which  the  Cerebellum  is  affected ;  whilst  in  other  cases  of  disease  or 
injury  involving  extensive  destruction  of  the  substance  of  the  organ,  there  has 
been  a  complete  abatement  of  sexual  desire.  The  proportion  of  recorded  cases 
of  disease  of  the  Cerebellum,  however,  in  which  any  affection  of  the  genital  organs 
has  been  noticed,  is  extremely  small;  for  out  of  178  cases,  which  have  been  col- 
lected by  Burdach,1  only  10,  or  scarcely  more  than  1  in  18,  presented  any 
symptoms  that  tended  to  indicate  a  functional  relation  between  the  Cerebellum 
and  the  Genital  organs.  The  same  physiologist  affirms  that  similar  affections 
present  themselves  when  the  Cerebrum  is  the  seat  of  the  lesion ;  and  there 
seems  a  strong  probability  that  it  is  solely  to  the  connection  of  these  organs  with 
the  Spinal  Cord  that  such  affections  of  the  genital  apparatus  are  due.  For 
erection  of  the  penis  has  been  noticed  in  a  far  larger  proportion  of  cases  in  which 
the  Spinal  Cord  itself  has  been  the  seat  of  the  lesion  ;  thus  in  15  cases  in  which 
the  cervical  portion  of  the  Cord  was  affected,  erection  of  the  penis  was  observed 
in  8 ;  and  in  13  cases  of  lesion  of  the  dorso-lumbar  portion  of  the  cord,  erection 
of  the  penis  took  place  in  3.a  It  is  well  known  that  erection  of  the  penis 
and  emissio  seminis  are  not  infrequent  phenomena  of  death  by  hanging;  and 
this  fact  accords  fully  as  well  with  the  idea  that  the  affection  of  the  sexual 
organs  is  consequent  upon  lesion  of  the  Cranio-Spinal  axis,  as  with  the  doctrine 
that  it  is  due  to  disordered  function  of  the  Cerebellum. — It  has  been  suggested 
by  Serres,3  who  collected  7  cases  in  which  excitement  of  the  genital  organs  was 

1  "  Von  Baue  und  Leben  des  Gehirns"  (Leipzig,  1819-26),  band  iii. 

2  See  the  "  Traite  des  Maladies  de  la  Moelle  Epiniere"  of  M.  Ollivier  (d' Angers),  oeme 
edit.,  torn.  iii.  p.  316. 

3  "  Anatomic  Compnree  du  Cerveau,"  torn.  ii.  p.  001,  717. 


OF   THE   CEREBELLUM,    AND   ITS   FUNCTIONS.  739 

coincident  with  apoplexy  of  the  median  lobe  of  the  Cerebellum,  that,  whilst  the 
lateral  lobes  or  hemispheres  may  be  connected  with  the  locomotive  function, 
the  median  lobe  may  be  the  organ  of  the  sexual  instinct.  Several  cases  have 
been  recorded,  in  which  some  such  relation  appeared  to  be  indicated ;  and  the 
Author  has  been  made  acquainted  with  at  least  six,1  in  which  an  extraordinary 
salacity  developed  itself  at  an  advanced  period  of  life,  whilst  concurrently  with 
this,  or  following  upon  it,  there  was  that  kind  of  unsteadiness  of  gait  which  may 
be  held  to  indicate  chronic  disease  of  the  Cerebellum;  and  in  one  of  these  cases, 
of  which  the  history  and  post-mortem  appearances  have  been  carefully  recorded 
by  Mr.  Dunn,2  there  was  strong  evidence  that  the  excitement  of  the  sexual  pro- 
pensity was  coincident  with  the  irritative  stage  of  incipient  disease  in  the  central 
lobe  of  the  Cerebellum,  and  that  the  abatement  of  the  propensity  was  in  like 
manner  coincident  with  the  subsequent  destruction  of  its  substance ;  whilst  the 
advance  of  the  disease  into  the  lateral  lobes  was  marked  by  impairment  of  the 
power  of  co-ordination  of  movement.  But  with  regard  to  all  such  cases,  and 
others  that  may  be  ranked  in  the  same  category,3  the  objection  of  Petrequin* 
holds  good,  that  when  disease  or  injury  affects  the  median  lobe  of  the  Cerebel- 
lum, the  Medulla  Oblongata  is  almost  certain  to  be  implicated  in  it ;  so  that,  as 
the  evidence  already  referred  to  clearly  indicates  the  existence  of  a  special  rela- 
tion between  the  genital  organs  and  the  upper  part  of  the  Spinal  Axis,  no 
positive  proof  is  afforded  by  them  that  any  portion  of  the  Cerebellum  has  any 
special  connection  with  the  generative  function. 

771.  The  Author  is  far  from  denying  in.  toto,  that  any  peculiar  connection 
exists  between  the  Cerebellum  and  the  Genital  system  ;  but  if  the  evidence  at 
present  adduced  in  support  of  the  Phrenological  position  be  held  sufficient  to 
establish  it,  in  defiance  of  so  many  opposing  considerations,  we  must  bid  adieu 
to  all  safe  reasoning  in  Physiology.  The  weight  of  testimony  appears  to  him 
to  be  quite  decided  in  regard  to  the  connection  of  the  Cerebellum  with  the 
regulation  of  the  motor  function;  and  as  an  additional  argument  in  favor  of 
this  view,  it  may  be  stated,  that  the  lobes  of  the  Human  Cerebellum  undergo 
their  most  rapid  development  during  the  first  few  years  of  life,  when  a  large 
number  of  complex  voluntary  movements  are  being  learned  by  experience,  and 
are  being  associated  by  means  of  the  muscular  sensations  accompanying  them ; 
whilst  in  those  animals  which  have,  immediately  after  birth,  the  power  of  regu- 
lating their  voluntary  movements  for  definite  objects,  with  the  greatest  precision, 
the  Cerebellum  is  more  fully  developed  at  the  time  of  birth.  In  both  instances 
it  is  well  formed  and  in  active  operation  (so  far  as  can  be  judged  of  by  the 
amount  of  circulation  through  it),  long  before  the  sexual  instinct  manifests 
itself  in  any  perceptible  degree. — But  neither  doctrine  need  be  maintained  alto- 
gether to  the  exclusion  of  the  other;  and  there  are  many  among  the  Phrenolo- 
gists of  the  present  day  who  hold  with  Serres  that  whilst  the  hemispheres  of  the 
Cerebellum  possess  the  endowments  now  generally  assigned  to  them  by  Physi- 
ologists, the  central  lobe  is  connected  with  the  genital  function.  It  has  been 

1  Four  such  cases  have  come  under  the  notice  of  his  friend  Dr.  Simpson  of  York. 

2  "  Medico-Chirurgical  Transactions,"  vol.  xxxii. 

3  Thus,  a  case  has  been  communicated  to  the  Author  by  Mr.  Turley  of  Worcester,  in 
which  the  sexual  desire,  which  had  been  always  strong  through  life,  but  which  had  been 
controlled  within  the  limits  of  decency,  manifested  itself  during  a  period  of  some  months 
preceding  death,  in  a  most  extraordinary  degree ;  on  post-mortem  examination,  a  tumor 
was  found  on  the  Pons  Varolii. — And  he  has  been  informed  of  another  case  by  Dr.  Evanson 
(formerly  of  Dublin),  in  which  a  young  officer  on  the  eve  of  marriage,  having  received  a  blow 
on  the  occiput  by  a  fall  from  his  horse,  became  impotent,  without  any  other  disorder  of  his 
bodily  or  mental  powers ;  and  in  the  distress  consequent  upon  this  discovery,  committed 
suicide  on  the  morning  fixed  for  his  wedding. 

4  "Sur  quelques  points  de  la  Physiologic  du  Cervelet  et  de  la  Moelle  Epiniere,"  in 
"  Gaz.  Medicale,"  1836,  torn.  iv.  p.  546. 


740  OP  THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

shown  by  Dr.  N.  S.  Davis,1  however,  that  there  is  no  perceptible  difference  in 
the  dimensions  of  this  central  lobe,  any  more  than  in  those  of  the  hemispheres, 
between  Bulls  and  Oxen ;  and  no  proof  has  yet  been  offered,  save  that  afforded 
by  the  pathological  evidence  just  referred  to,  that  any  such  endowment  is  pos- 
sessed by  it.  That  in  some  way  or  other,  however,  either  the  central  portion  of 
the  Cerebellum,  or  some  part  of  the  Medulla  Oblongata,  has  a  special  connection 
with  the  Generative  function,  appears  to  the  Author  to  be  indicated  with  tole- 
rable clearness  by  several  of  the  pathological  phenomena  already  cited.  The 
circumstance,  too,  of  which  he  has  frequently  been  assured,  that  great  application 
to  gymnastic  exercises  diminishes  for  a  time  the  sexual  vigor,  and  even  totally 
suspends  desire,  seems  worthy  of  consideration  in  reference  to  such  a  view;  for 
if  the  Cerebellum  be  really  connected  with  both  kinds  of  function,  it  does  not 
seem  unreasonable  that  the  excessive  employment  of  it  upon  one  should  diminish 
its  energy  in  regard  to  the  other. — An  analysis  of  the  nature  of  the  Sexual  pro- 
pensity, however,  suggests  the  conclusion  that  we  are  not  to  look  in  this  part  of 
the  Encephalon  for  anything  else  than  a  seat  of  the  sexual  sensation;  the  cha- 
racter of  which  seems  to  be  sufficiently  different  from  that  of  mere  tactile  sensa- 
tion, to  require  a  distinct  ganglionic  centre.  Such  a  centre  would  be  likely  to 
be  placed  in  the  line  of  the  other  sensory  ganglia,  and  in  close  connection  with 
them. 

772.  As  in  the  case  of  other  sensations,  the  sexual,  when  moderately  excited, 
may  give  rise  to  ideas,  emotions,  and  desires,  of  which  the  Cerebrum  is  the  seat; 
and  these  may  react  on  the  muscular  system  through  the  Intelligence  and  Will. 
But  when  inordinately  excited,  or  when  not  kept  in  restraint  by  the  Will,  the 
sexual  sensations  will  at  once  call  into  play  respondent  movements,  which 
are  then  to  be  regarded  as  purely  automatic;  this  is  the  case  in  Nymphomania 
and  Satyriasis  in  the  Human  subject;  and  it  is  probably  also  the  ordinary  mode 
of  operation  of  this  sense  in  such  of  the  lower  animals  as  have  not  psychical 
power  enough  to  form  a  conception  of  an  absent  object  of  gratification,  and 
cannot,  therefore,  be  said  to  have  sexual  desires.  Thus,  like  other  sensations, 
it  may  act  either  intelligentially  or  automatically  ;  giving  rise  to  ideas,  by 
transmission  to  the  Cerebrum,  which  ideas,  associated  with  pleasurable  feelings, 
originate  desires,  which  stimulate  the  reasoning  powers  to  devise  means  for  their 
gratification,  and  excite  the  will  to  the  necessary  actions;  or,  by  its  immediate 
action  upon  the  motor  apparatus,  producing  respondent  movements. — Of  this 
double  modus  operandi  we  seem  to  have  sufficient  evidence.  For,  among  many 
of  the  lower  tribes  of  animals,  at  the  time  when  the  generative  organs  are  in  a 
state  of  functional  activity,  the  presence  of  an  individual  of  the  opposite  sex, 
indicated  by  the  sight,  smell,  hearing,  or  touch,  immediately  excites  the  whole 
train  of  instinctive  actions  concerned  in  the  reproductive  operation;  whilst  we 
have  no  evidence  in  them  of  any  voluntary  exertion,  resulting  from  the  existence 
of  a  desire  entertained  in  the  absence  of  the  object,  and  intended  for  the  gratifi- 
cation of  that  desire.  In  Man,  on  the  other  hand,  the  principal  operation  of 
the  sexual  sensations  is  in  awakening  desires  and  affections,  which  serve  as 
excitements  to  the  intelligence  and  as  motives  to  the  will;  and  it  is  only,  under 
ordinary  circumstances,  when  the  two  sexes  have  been  thus  brought  into  close 
relation,  that  the  direct  reaction  of  the  sexual  sensation  manifests  itself  in  auto- 
matic movements.  In  cases,  however,  in  which  this  sensation  is  excited  in 
unusual  strength,  it  may  completely  overmaster  all  motives  to  the  repression  of 
the  propensity,  and  may  even  entirely  remove  the  actions  from  the  control  of 
the  will;  and  a  state  of  a  very  similar  kind  exists  in  many  idiots,  in  whom  the 
sexual  propensity  exerts  a  dominant  power,  not  because  it  is  in  itself  peculiarly 

1  "Transactions  of  American  Medical  Association,"  vol.  iii.  p.  415. 


THE   CEREBRUM,   AND   ITS   FUNCTIONS.  741 

strong,  but  because,  the  intelligence  being  undeveloped,  it  acts  without  control 
or  direction  from  the  will. 

5. — The  Cerebrum,  and  its  Functions. 

773.  We  come,  in  the  last  place,  to  consider  the  functions  of  that  portion  of 
the  Nervous  Centres,  which  is  evidently,  in  Man,  the  predominant  organ  of  his 
whole  system ;  being  not  merely  the  instrument  of  his  reasoning  faculties,  but 
also  possessing  a  direct  or  indirect  control  over  nearly  all  the  actions  of  his  cor- 
poreal frame,  save  those  purely  vegetative  processes  which  are  most  completely 
isolated  from  his  animal  powers.     We  should  be  in  great  danger,  however,  of 
coming  to  an  erroneous  conclusion  as  to  the  real  character  of  the  Cerebrum  and 
of  its  operations,  if  we  confined  ourselves  to  the  study  of  the  Human  organism; 
and  the  history  of  Physiological  science  shows  that  every  advance  of  knowledge 
respecting  its  functions  has  tended  to  limit  them,  whilst  at  the  same  time  ren- 
dering them  more  precise.     Thus  the  Brain  (this  term,  in  the  older  Anatomy, 
being  chiefly  appropriated  to  the  Cerebrum)  was  accounted,  not  merely  the  centre 
of  all  motion  and  sensation,  but  also  the  source  of  all  vitality ;  the  different  pro- 
cesses of  nutrition,   secretion,  &c.,  being  maintained,  it  was  supposed,  by  a 
constant  supply  of  "  animal  spirits,"  propagated  from  the  brain,  along  the  nerves, 
to  each  individual  part.     The  more  modern    doctrine,  that  the    Sympathetic 
System  has  for  its  special  function  to  supply  the  nervous  influence  requisite  for 
the  maintenance  of  the  functions  of  Organic  life,  was  the  first  step  in  the  process 
of  limitation  ;  still  the  Brain  was  regarded  as  the  centre  of  all  the  Animal  func- 
tions ;  and  no  other  part  was  admitted  to  possess  any  power  independently  of  it. 
By  experiments  and   pathological    observations,  however,  the  powers   of  the 
Spinal  Cord  as  an  independent  centre  of  action  were  next  established;  and  it  was 
thus  shown  that  there  is  a  large  class  of  motions  in  which  the  Brain  has  no 
concern,  and  that  the  removal  of  the  Cerebral  hemispheres  is  not  incompatible 
(even  among  the  higher  Vertebrata)  with  the  prolonged  maintenance  of  a  sort 
of  inert  and  scarcely  conscious  life.     Still  it  has  been  usually  maintained,  and 
with  great  show  of  reason,  that  the  Cerebrum  is  the  instrument  of  all  psychical 
operations,  and  the  originator  of  all  the  movements  which  could  not  be  assigned 
to  the  reflex  action  of  the  Spinal  Cord.     An  attempt  has  been  made,  however,  in 
the  preceding  pages,  to  show  that  this  view  is  not  correct;  and  that  there  is  a  class 
of  actions,  neither  excito-motor  nor  voluntary,  but  directly  consequent  upon 
Sensations,  and  constituting  (with  the  excito-motor)  the  truly  instinctive  actions 
which  may  be  justly  assigned  to  certain  ganglionic  centres,  not  less  independent 
of  the  Cerebrum  than  is  the  Spinal  Cord  itself.     It  has  been  further  advanced, 
that  the  Cerebrum  must  be  considered  in  the  light  of  an  organ  superadded  for 
a  particular  purpose  or  set  of  purposes,  and  not  as  one  which  is  essential  to 
life ;  that  it  has  no  representative  among  the  Invertebrata  (except  in  a  few  of 
the  highest  forms,  which  evidently  present  a  transition  towards  the  Vertebrated 
series) :  and  that,  at  its  first  introduction,  in  the  class  of  Fishes,  it  evidently 
performs   a  subordinate  part  in  the  general  actions  of  the  Nervous  System. 
Hence,  whatever  be  the  function,  or  set  of  functions,  we  assign  to  the  Cerebrum, 
we  must  keep  in  view  the  special  character  of  the  organ ;  and  must  never  lose 
sight  of  the  fact  that  its  predominance  in  Man  does  not  deprive  other  parts  of 
their  independent  powers,  although  it  may  keep  the  exercise  of  those  powers  in 
check,  and  may  considerably  modify  their  manifestations. 

774.  Before  proceeding  to  inquire  into  the  Physiology  of  the  Cerebrum,  we 
may  advantageously  take  notice  of  some  of  the  leading  features  of  its  structure. 
— In  the  first  place,  it  forms  an  exception  to  the  general  plan  on  which  the  ele- 
ments of  ganglionic  centres  are  arranged  :  in  having  its  vesicular  substance  on 
the  exterior,  instead  of  in  the  central  part  of  the  mass.     The  purpose  of  this  is 


742  OP   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

probably  to  allow  the  vesicular  matter  to  be  disposed  in  such  a  manner  as  to 
present  a  very  large  surface,  instead  of  being  aggregated  together  in  a  more 
compact  mass ;  and  by  this  means  to  admit,  on  the  one  side,  the  more  ready 
access  of  the  bloodvessels  which  are  so  essential  to  the  functional  operations  of 
this  tissue,  as  well  as  the  more  ready  communication,  on  the  other,  with  the  vast 
number  of  fibres  by  which  its  influence  is  to  be  propagated.  There  is  no  reason 
whatever  to  believe  that  the  relative  functions  of  the  vesicular  and  fibrous  sub- 
stances are  in  the  least  altered  by  this  change  in  their  relative  position  ;  indeed 
the  results  of  observation  upon  the  phenomena  of  disordered  Cerebral  action  are 
such  as  to  afford  decided  confirmation  to  the  doctrine  already  propounded,  that 
the  action  of  the  vesicular  matter  constitutes  the  source  of  nervous  power,  whilst 
the  fibrous  structure  has  for  its  office  to  conduct  the  influence  generated  in  it 
towards  the  points  at  which  this  is  to  operate.  The  purpose  of  this  arrangement 
is  further  evidenced  by  the  fact  that,  in  all  the  higher  forms  of  Cerebral  struc- 
ture, we  find  a  provision  for  a  still  greater  extension  of  the  surface  at  which  the 
vesicular  matter  and  the  bloodvessels  may  come  into  relation  ;  this  being  effected 
by  the  plication  of  the  layer  of  vesicular  matter  into  "  convolutions/'  into  the 
sulci  between  which  the  highly  vascular  membrane  known  as  the  "  pia  mater" 
dips  down,  sending  multitudes  of  small  vessels  from  its  inner  surface  into  the 
substance  it  invests. — In  the  fibrous  or  medullary  substance  of  which  the  great 
mass  of  the  Cerebrum  is  composed,  three  principal  sets  of  fibres  may  be  distin- 
guished. These  are — first,  the  radiating  fibres,  which  connect  the  vesicular 
matter  of  the  cortical  substance  of  the  Hemispheres  with  the  Thalami  Optici, 
and  which,  if  our  view  of  the  function  of  the  latter  be  correct,  may  be  regarded 
as  ascending  or  sensory ; — second,  the  radiating  fibres,  which  connect  the  vesi- 
cular matter  of  the  cortical  substance  of  the  Hemispheres  with  the  Corpora 
Striata,  and  which,  on  similar  grounds,  may  be  regarded  as  descending  or  motor  ; 
— and  third,  the  Commissural  fibres,  which  establish  the  connection  between 
the  opposite  Hemispheres,  and  between  the  different  parts  of  the  vesicular  sub- 
stance of  the  same  side,  especially  between  that  disposed  on  the  surface  of  each 
hemisphere,  and  those  isolated  patches  which  are  found  in  its  interior.  It  is 
on  the  very  large  proportion  which  the  Commissural  fibres  bear  to  the  rest,  that 
the  bulk  of  the  Cerebrum  of  Man  and  of  the  higher  animals  seems  chiefly  to 
depend ;  and  it  is  easy  to  conceive  that  this  condition  has  an  important  relation 
with  the  operations  of  the  Mind,  whatever  be  our  view  of  the  relative  func- 
tions of  different  parts  of  the  Cerebrum.  It  appears,  from  the  late  researches 
of  M.  Baillarger,  that  the  surface  and  the  bulk  of  the  cerebral  hemispheres 
are  so  far  from  bearing  any  constant  proportion  to  each  other,  in  different 
animals,  that,  notwithstanding  the  depth  of  the  convolutions  in  the  Human 
Cerebrum,  its  bulk  is  2£  times  as  great  in  proportion  to  its  surface,  as  it  is  in 
the  Rabbit,  the  surface  of  whose  Cerebrum  is  smooth.  The  entire  surface  of 
the  Human  Cerebrum,  when  the  convolutions  are  unfolded,  is  estimated  by 
him  at  about  670  square  inches.1  - 

775.  With  regard  to  the  Radiating  fibres,  which  connect  the  Corpora  Striata 
and  Thalami  Optici  with  the  vesicular  surface  of  the  Cerebral  hemispheres,  no 
positive  proof  has  yet  been  obtained  of  their  direct  continuity  with  those  which 
enter  into  the  composition  of  the  nerves  proceeding  from  the  Spinal  Cord  and 
Medulla  Oblongata;  and  we  have  seen  (§  753)  that  there  a»e  certain  phenomena, 

1  The  inference  drawn  by  M.  Baillarger  from  the  facts  he  has  collected — namely,  that 
the  proportional  surface  of  vesicular  matter  in  different  animals,  whether  considered  abso- 
lutely, or  relatively  to  the  volume  of  the  Cerebrum,  has  no  correspondence  with  their 
intellectual  capability — is  far  too  sweeping  an  assumption ;  since,  as  above  shown,  the 
increase  in  the  Commissural  fibres,  causing  an  augmentation  of  the  bulk  of  the  Cerebrum, 
may  be  alike  the  cause  of  increased  intelligence  and  of  a  diminished  proportional  amount 
of  vesicular  matter ;  though  the  latter  still  remains  as  the  original  source  of  power. 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  743 

which  are  far  better  explained  on  the  idea  that  these  radiating  fibres  are  of  a 
commissural  nature  only,  serving  to  connect  the  vesicular  matter  of  the  Cerebrum 
with  that  of  the  higher  portions  of  the  Cranio-Spinal  Axis,  through  which  alone 
they  are  brought  into  relation  with  the  central  terminations  of  the  afferent 
nerves,  and  with  the  origins  of  the  motor.  On  this  view,  the  Cerebrum  would 
receive  all  its  sensory  impressions  by  the  commissural  fibres  that  connect  it  with 
the  ganglia,  which  are  the  real  centres  of  these  nerves ;  whilst  it  would  call  the 
motor  trunks  into  action,  by  exciting,  through  another  set  of  commissural  fibres, 
the  vesicular  matter  of  the  ganglionic  centres  from  which  they  pass  forth.  The 
idea  that  there  is  no  direct  continuity  between  the  radiating  fibres  of  the  Cere- 
brum and  the  fibres  of  the  nerve-trunks  derives  support  from  the  fact,  in  which 
the  results  of  all  experiments  agree,  that  no  irritation  of  the  former  produces 
either  sensation  or  motion.  These  results  are  borne  out  by  pathological  ob- 
servations in  Man ;  for  it  has  been  frequently  remarked,  when  it  has  been 
necessary  to  separate  protruded  portions  of  the  Brain  from  the  remainder,  that 
this  has  given  rise  to  no  sensation,  even  in  cases  in  which  the  mind  has  been 
perfectly  clear  at  the  time,  nor  has  any  convulsive  action  been  produced.  Such 
evidence,  however,  is  by  no  means  conclusive  on  the  point ;  since  the  same  is 
true  of  the  Thalami  Optici  and  Corpora  Striata,  in  which  there  is  more  decided 
evidence  of  the  absolute  continuity  of  fibres  from  the  nerve-roots  to  the  vesicular 
substance  of  these  parts  respectively. 

776.  The  Commissural  fibres  constitute  two  principal  groups,  the  transverse, 
and  the  longitudinal;  the  former  connecting  the  two  Hemispheres  with  each 

[Fig.  194f. 


This  figure  is  intended  to  show  the  course  and  connection  of  the  fibres  of  the  great  transverse  commissure  of 
the  hemispheres  or  corpus  callosum.  The  dissection  has  only  been  carried  into  the  right  hemisphere.  It  will  be 
seen  that  these  fibres  ascend  to  the  convolutions  above  the  mesial  line,  p  p  P.  Fibres  of  the  corpus  callosum 
radiating  into  the  hemispherical  ganglion.  B.  Left  hemispherical  ganglion  undissected.  E.  Cerebellum. 
Near  the  centre  of  the  drawing,  and  a  little  to  the  right  of  the  mesial  line,  is  the  representation  of  a  broken 
fasciculus  of  fibres — the  part  torn  off  was  traced  most  carefully  into  the  convoluted  surface  of  the  brain. — ED.] 


744 


OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 


other;  the  latter  uniting  the  different  parts  of  the  same  Hemisphere. — Of  the 
transverse  commissures,  the  Corpus  Callosum  is  the  most  important.  This 
consists  of  a  mass  of  fibres  very  closely  interlaced  together ;  which  may  be 
traced  into  the  substance  of  the  hemispheres  on  each  side,  particularly  at  their 
lower  part,  where  their  connections  are  the  closest  with  the  Thalami  Optiei  and 
Corpora  Striata.  It  is  difficult,  if  not  impossible,  to  trace  its  fibres  any  further; 

[Fig.  194J. 


This  figure  represents  longitudinal  fibres  placed  above  the  great  transverse  commissure  corresponding  with 
those  which  we  have  just  observed  below  it — the  superior  longitudinal  commissure.  The  relations  being  more 
simple  than  those  of  the  inferior  commissure,  are  simply  designated  by  the  letters  s  L,  s  L.  They  are  traced, 
ascending  forwards,  from  the  locus  quadratus,  which  is  anterior  to  the  fissura  Sylvii,  and  then,  curving  back- 
wards and  winding  round  the  front  of  the  great  transverse  commissure  (p),  receiving  fibres  from  all  the  con- 
volutions at  the  upper  and  sides  of  the  hemispheres,  winding  round  the  posterior  extremity  of  the  same  com- 
missure, and  terminating  after  crossing  the  fissura  Sylvii,  where  it  commenced  in  the  locus  quadratus  at  the 
base  of  the  brain.  H.  Spinal  cord.  J.  Pituitary  gland,  just  above  which  is  the  divided  optic  nerve.  N.  Letter 
placed  on  the  crus  cerebri,  and  behind  that  root  of  the  fornix  which  springs  from  the  interior  of  the  thalamus. 
P.  Great  transverse  commissure.  S.  Olivary  ganglion,  a.  Olfactory  ganglion,  c  D.  Optic  ganglia,  c  a.  Cor- 
pus mammillare,  formed  by  the  twist  of  the  fornix.  c  m.  Commissura  mollis  in  the  third  ventricle,  k.  Optic 
thalamus.  o.  Peduncle  of  the  pineal  gland :  if  this  line  is  traced  backwards,  it  will  be  found  connected  with  a 
dark  rounded  body,  the  pineal  gland,  which  is  lying  on  the  anterior  optic  tubercle — nates;  if  this  line  is  traced 
forwards,  it  will  be  seen  joining  the  anterior  pillar  of  the  fornix,  which  has  been  turned  down  to  show  this 
connection.  The  divided  end  of  the  fornix  is  turned  towards  us.  p  c.  Posterior  commissure,  s.  Taenia  semi- 
circularis  joining  the  fornix  at  the  same  point.  This  letter  is  placed  in  the  anterior  cornu  of  the  lateral 
ventricle  on  the  corpus  striatum.  This  junction  is  very  distinct  in  both  the  recent  and  hardened  brain, 
though  the  connecting  fibres  are  too  delicate  to  be  done  justice  to  in  a  woodcut.  4.  Fourth  ventricle.  P.  Iter 
a  tertio  ad  quartum  ventriculum.  c.  Posterior  commissure. — ED.] 

but  there  can  be  little  doubt  that  they  radiate,  with  the  fibres  proceeding  from 
the  bodies  just  named,  to  different  parts  of  the  cortical  substance  of  the 
Hemispheres.  This  commissure  is  altogether  wanting  in  Fish,  lleptiles,  and 
Birds;  and  it  is  partially  or  completely  wanting  in  those  Mammals  whose 
Cerebrum  is  formed  upon  the  least  complex  plan — the  Rodents  and  Marsupials. 
The  Anterior  commissure  particularly  unites  the  Corpora  Striata  of  the  two  sides : 
but  many  of  its  fibres  pass  through  those  organs,  and  radiate  towards  the  convo- 


THE   CEREBRUM,    AND   ITS   FUNCTIONS. 


745 


lutions  of  the  Hemispheres,  especially  those  of  the  middle  lobe.  [Fig.  189*, 
a,  c. — ED.]  This  commissure  is  particularly  large  in  those  Marsupials  in  which 
the  Corpus  Callosum  is  deficient.  The  Posterior  commissure  is  a  band  of  fibres 
which  connects  together  the  Thalami  Optici ;  crossing  over  from  the  posterior 
extremity  of  one  to  that  of  the  other.  [Fig.  194 J,  p.  c. — ED.]  Besides  these,  there 
are  other  groups  of  fibres,  which  appear  to  have  similar  commissural  functions, 
but  which  are  intermingled  with  vesicular  substance.  Such  are  the  soft  commis- 
sure, which  also  extends  between  the  Thalami ;  the  Pons  Tarini,  which  extends 
between  the  Crura  Cerebri;  and  the  Tuber  Cinereum,  which  seems  to  unite  the 
optic  tracts  with  the  thalami,  the  corpus  callosum,  the  foruix,  &c.,  and  to  be  a 
common  point  of  meeting  for  several  distinct  groups  of  fibres. — Of  the  longitudi- 
nal commissures,  some  lie  above,  and  others  below,  the  Corpus  Callosum.  Upon 
the  transverse  fibres  of  that  body,  there  is  a  longitudinal  tract  on  each  side  of  the 
median  line,  which  serves  to  connect  the  convolutions  of  the  anterior  and  pos- 
terior Cerebral  lobes.  Above  this,  again,  is  the  Superior  longitudinal  commissure 
[Fig.  194J — ED.],  which  is  formed  by  the  fibrous  matter  of  the  greater  convo- 
lutions nearest  the  median  plane  on  the  upper  surface  of  the  Cerebrum,  and  which 
connects  the  convolutions  of  the  anterior  and  middle  lobes  with  those  of  the 


[Fig.  194 


This  figure  has  been  introduced  with  the  view  of  assisting  the  student  in  his  study  of  the  relations  of  the 
inferior  longitudinal  commissure  or  fornix,  which  may  he  described  as  commencing  in  the  centre  of  the  thala- 
mus  nervi  optici  (L),  proceeding  from  thence  to  the  base  of  the  brain,  where  it  suddenly  bends  upwards  and 
forwards,  forming  by  this  turn  the  knuckle  (B),  which  is  called  corpus  albicans  or  mammillare.  This  body 
receives  a  few  fibres  (A)  from  the  locus  niger  (6)  in  the  crus  cerebri  (5),  running  forward  from  thence  towards 
the  anterior  commissure,  receiving  fibres  from  the  convolutions  at  the  base  of  the  brain,  crossing  and  as  it  were 
kneeling  upon  the  anterior  commissure  (s),  and,  ascending  towards  the  great  transverse  commissure,  forms 
the  anterior  pillar  of  the  fornix  (c),  receiving  fibres  in  its  course  from  the  under  and  front  part  of  the  anterior 
lobes,  and  thus  forming  the  septum  lucidum  (D)  ;  running  back  from  thence,  passing  in  its  course  backwards 
over  the  thalamus  nervi  optici  (L),  it  spreads  laterally,  constituting  that  portion  which  is  called  the  body  of 
the  fornix  (E)  :  descending  again  at  the  back  part  of  the  brain,  it  forms  the  descending  or  posterior  pillar  of  the 
fornix  tcenia  hippocampi  (F),  some  of  its  fibres  running  back  to  be  connected  with  the  posterior  lobes  (i) ;  others 
crossing  the  projection  called  hippocampus  major  (G),  to  be  connected  with  the  middle  lobe,  and  others  again 
passing  over  the  pes  hippocampi  (H)  to  be  connected  with  the  anterior  portion  of  the  middle  lobe.  Thus  does 
this  commissure  connect  different  portions  of  the  convoluted  surface  of  the  brain  together,  which  are  inferior 
to  the  great  transverse  commissure,  and  on  the  same  side  of  the  mesial  line.  A.  Fibres  of  the  inferior  longitudi- 
nal commissure,  or  fornix,  from  the  locus  niger.  B.  Corpus  mammillare.  c.  Anterior  pillars  of  inferior  longitudi- 
nal commissure,  or  fornix.  D.  Septum  lucidum.  E.  Body  of  the  fornix,  or  centre  of  the  commissure.  F.  Tcenia 
hippocampi,  or  descending  fibres  of  the  inferior  longitudinal  commissure.  G.  Fibres  covering  the  hippocampus 
major.  H.  Fibres  covering  the  pes  hippocampi,  i.  Fibres  covering  the  hippocampus  minor.  K.  Great  trans- 
verse commissure  divided  in  the  mesial  line.  L.  Posterior  cerebral  ganglion,  or  thalamus.  1.  Anterior  corn, 
missure.  5.  Section  of  the  crus  cerebri.  6.  Locus  niger.  7.  Anterior  cerebral  ganglion,  or  corpus  striatum 
partially  scraped  away. — ED.] 


746  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

posterior.  Beneath  the  Corpus  Callosum,  we  find  the  most  extensive  of  all  the 
longitudinal  commissures,  the  Fornix.  [Fig.  194§. — ED.]  This  is  connected  in 
front  with  the  Thalami  Optici,  the  Corpora  Mammillaria,  the  Tuber  Cinereum,  &c.; 
and  behind,  it  spreads  its  fibres  over  the  Hippocampi  (major  and  minor),  which 
are  nothing  else  than  peculiar  convolutions  that  project  into  the  posterior  and 
descending  cornua  of  the  lateral  ventricles.  The  fourth  longitudinal  commissure 
is  the  Taenia  semicircular  is,  which  forms  part  of  the  same  system  of  fibres  with 
the  fornix ;  connecting  the  corpus  mammillare  and  thalamus  opticus  of  each 
side  with  the  middle  lobe  of  the  cerebral  hemisphere.  If,  as  Dr.  Todd  has 
remarked,1  we  could  take  away  the  corpus  callosum,  the  gray  matter  of  the 
internal  convolution,  and  the  ventricular  prominence  of  the  optic  thalami,  then 
all  these  commissures  would  fall  together,  and  would  become  united  in  the  same 
series  of  longitudinal  fibres. — Experiment  does  not  throw  any  light  upon  the 
particular  functions  of  the  Corpus  Callosum  and  other  Commissures;  since  they 
can  scarcely  be  divided  without  severe  general  injury.  It  would  appear,  how- 
ever, that  the  partial  or  entire  absence  of  these  parts,  reducing  the  Cerebrum 
(in  this  respect  at  least)  to  the  level  of  that  of  the  Marsupial  Quadruped,  or  of 
the  Bird,  is  by  no  means  an  unfrequent  cause  of  deficient  intellectual  power.2 

777.  The  weight  of  the  entire  Encephalon  in  the  adult  Male  usually  ranges 
between  40  and  60  oz.,  the  average  being  about  50  oz. ;  and  in  the  Female, 
from  36  to  50  oz.,  the  average  being  about  45  oz.  The  maximum  of  the 
healthy  brain  seems  to  be  about  64  oz.,  and  the  minimum'  about  31  oz.  But  in 
cases  of  idiocy,  the  amount  is  sometimes  much  below  this ;  as  low  a  weight  as 
20  ounces  having  been  recorded. — It  appears,  from  the  recent  investigations  of 
M.  Bourgery,  that  the  relative  sizes  of  the  different  component  elements  of  the 
Human  Encephalon  are  somewhat  as  follows  :  Dividing  the  whole  into  204 
parts,  the  weight  of  the  Cerebrum  will  be  represented  by  about  170  of  those 
parts,  that  of  the  Cerebellum  by  21,  and  that  of  the  Medulla  Oblongata  with 
the  Optic  Thalami  and  Corpora  Striata  at  13.  The  weight  of  the  Spinal  Cord 
would  be,  on  the  same  scale,  7  parts.  Hence  the  Cerebral  Hemispheres  of  Man 

1  "Anatomy  of  the  Brain,  Spinal  Cord,"  &c.,  p.  234. 

2  The  following  case  of  deficient  commissures,  recorded  by  Mr.  Paget  ("  Medico-Chirurg. 
Transactions,"  vol.  xxiv.),  is  of  much  interest.     The  middle  portion  of  the  Fornix,  and  the 
whole  of  the  Septum  Lucidum,  were  absent;   and  in  place  of  the  Corpus  Callosum,  there 
was  only  a  thin  fasciculated  layer  of  fibrous  matter,  l-4th  inch  in  length,  but  of  which  the 
fibres  extended  to  all  the  parts  of  the  brain  into  which  the  fibres  of  the  healthy  corpus 
callosum  can  be  traced.     The  Middle  commissure  was  very  large ;  and  the  lateral  parts  of 
the  Fornix,  with  the  rest  of  the  Brain,  were  quite  healthy.     The  patient  was  a  servant- 
girl,  who  died  of  pericarditis.     She  had  displayed,  during  her  life,  nothing  very  remarkable 
in  her  mental  condition,  beyond  a  peculiar  want  of  forethought  and  power  of  judging  of  the 
probable  event  of  things.     Her  memory  was  good ;  and  she  possessed  as  much  ordinary 
knowledge  as  is  commonly  acquired  by  persons  in  her  rank  of  life.     She  was  of  good  moral 
character,  trustworthy,  and  fully  competent  to  all  the  duties  of  her  station,  though  some- 
what heedless ;  her  temper  was  good,  and  disposition  cheerful. — The  mental  deficiencies 
in  most  of  the  few  other  cases  of  which  the  details  have  been  recorded  seem  to  have  been 
of  the  same  order ;  and  this  is  exactly  what  might  have  been  anticipated ;  since  the  de- 
privation of  these  parts  takes  away  that  which  is  most  characteristic  of  the  Cerebrum  of 
Man  and  of  the  higher  Mammalia ;  their  intellectual  operations  being  peculiarly  distinguished 
by  that  application  of  past  experience  to  the  prediction  of  the  future,  which  constitutes  one  of  the 
highest  efforts  of  Intelligence. — Another  case  has  been  since  put  on  record  by  Mr.  Mitchell 
Henry  (Op.  cit.,  vol.  xxxi.),  in  which  the  anterior  portion  of  the  Corpus  Callosum  was  defi- 
cient, together  with  the  middle  and  anterior  portion  of  the  Fornix,  and  the  whole  of  the  Sep- 
tum Lucidum.    There  was  in  this  case,  also,  a  marked  intellectual  deficiency,  but  apparently 
of  a  different  character  from  that  which  showed  itself  in  the  preceding  case ;  for,  instead 
of  vivacity  and  habitual  rapidity  of  action,  there  was  here  a  disproportionate  degree  of 
slowness  in  action,  amounting  almost  to  stupidity.     The  difference  in  the  two  cases,  how- 
ever, is  perhaps  to  be  set  down  rather  to  the  account  of  general  temperament;  since  in 
both  of  them  there  seems  to  have  been  a  deficiency  in  the  power  of  carrying  on  a  continuous 
train  of  thought. 


THE   CEREBRUM,    AND   ITS    FUNCTIONS.  747 

include  an  amount  of  nervous  matter,  which  is  four  times  that  of  all  the  rest 
of  the  Cranio-Spinal  mass,  more  than  eight  times  that  of  the, Cerebellum,  thir- 
teen times  that  of  the  Medulla  Oblongata,  &c.,  and  tiventy-four  times  that  of 
the  Spinal  Cord. — The  average  weight  of  the  whole  Encephalon,  in  proportion 
to  that  of  the  body,  in  Man,  taking  the  average  of  a  great  number  of  observa- 
tions, is  about  1  to  36.  This  is  a  much  larger  proportion  than  that  which  ob- 
tains in  most  other  animals ;  thus  the  average  of  Mammalia  is  stated  by  M. 
Leuret  to  be  1  to  186,  that  of  Birds  1  to  212,  that  of  Reptiles  1  to  1321,  and 
that  of  Fishes  1  to  5668.  It  is  interesting  to  remark,  in  reference  to  these 
estimates,  that  the  Encephalic  prolongation  of  the  Medulla  Oblongata  in  Man 
(being  about  one-sixteenth  of  the  weight  of  the  whole  Encephalon)  is  alone 
more  than  twice  as  heavy  in  proportion  to  his  body,  as  the  entire  Encephalon  of 
Reptiles,  and  ten  times  as  heavy  as  that  of  Fish. — But  there  are  some  animals 
in  which  the  weight  of  the  Encephalon  bears  a  higher  proportion  to  that  of  the 
body  than  it  does  in  Man ;  thus  in  the  Blue-headed  Tit,  the  proportion  is  as  1 
to  12,  in  the  Goldfinch  as  1  to  24,  and  in  the  Field-Mouse  as  1  to  31.  It  does 
not  hence  follow,  however,  that  the  Cerebrum  is  larger  in  proportion ;  in  fact, 
it  is  probably  not  nearly  so  large ;  for  in  Birds  and  Rodent  Mammals,  the  Sen- 
sory Ganglia  form  a  very  considerable  proportion  of  the  entire  Encephalon. 
The  importance  of  distinguishing  between  the  several  parts  of  this  mass,  which 
are  marked  out  as  distinct,  alike  by  their  structure  and  connections,  as  by  the 
history  of  their  development,  has  not  been  by  any  means  sufficiently  attended  to. 
778.  The  Encephalon  altogether  receives  a  supply  of  Blood,  the  amount  of 
which  is  very  remarkable,  when  its  comparative  bulk  is  considered  ;  the  propor- 
tion which  goes  to  it  being,  according  to  the  estimate  of  Haller,  as  much  as  one- 
fifth  of  the  whole.  The  manner  in  which  this  blood  is  conveyed  to  the  brain, 
and  the  conditions  of  its  distribution,  offer  some  peculiarities  worthy  of  notice. 
The  two  Vertebral  and  two  Carotid  arteries,  by  which  the  blood  enters  the 
cavity  of  the  cranium,  have  a  more  free  communication  by  anastomosis  than 
any  similar  set  of  arteries  elsewhere ;  and  this  is  obviously  destined  to  prevent 
an  obstruction  in  one  trunk  from  interrupting  the  supply  of  blood  to  the  parts 
through  which  its  branches  are  chiefly  distributed — the  cessation  of  the  circu- 
lation through  the  nervous  matter  being  immediately  productive  (as  formerly 
shown,  §  355)  of  suspension  of  its  functional  activity. — Not  only  must  there 
be  a  sufficient  supply  of  blood,  but  it  must  make  a  regulated  pressure  on  the 
walls  of  the  vessels.  Now  the  Encephalon  is  differently  circumstanced  from 
other  vascular  organs,  in  being  inclosed  within  an  unyielding  bony  case  (§  533) ; 
and  we  find  a  special  provision  for  equalizing  the  bulk  of  the  contents  of  this 
cavity,  and  for  counterbalancing  the  results  of  differences  in  the  functional  ac- 
tivity of  the  brain  and  in  its  supply  of  blood,  in  the  existence  of  a  fluid  which 
is  found  beneath  the  arachnoid,  both  on  the  surface  of  the  brain  and  spinal  cord, 
and  in  the  ventricles  of  the  former.  The  amount  of  this  "  cerebro-spinal  fluid" 
seems  to  average  about  two  ounces  j  but  in  cases  of  atrophy  of  the  brain,  as 
much  as  twelve  ounces  of  fluid  may  sometimes  be  obtained  from  the  cranio-spi- 
nal  cavity ;  whilst  in  all  instances  in  which  the  bulk  of  the  brain  has  under- 
gone an  increase,  whether  from  the  production  of  additional  nervous  tissue,  or 
from  undue  turgescence  of  the  vessels,  there  is  either  a  diminution  or  a  total 
absence  of  this  fluid.  It  appears  from  the  experiments  of  Magendie  (to  whom 
our  knowledge  of  the  importance  of  this  fluid  is  chiefly  due),  that  its  with- 
drawal in  living  animals  causes  great  disturbance  of  the  cerebral  functions,  pro- 
bably by  allowing  undue  distension  of  the  bloodvessels ;  it  is,  however,  capable 
of  being  very  rapidly  regenerated ;  and  its  reproduction  restores  the  nervous 
centres  to  their  natural  state. — As  the  "  cerebro-spinal  fluid"  can  readily  find 
its  way  from  the  subarachnoid  spaces  of  the  cranial  cavity  into  those  of  the 


748  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

spinal,  and  as  it  is  no  less  readily  absorbed  than  reproduced,  it  evidently  serves 
as  an  equalizer  of  the  amount  of  pressure  within  the  cranial  cavity ;  admitting 
the  distension  or  contraction  of  the  vessels  to  take  place,  within  certain  limits, 
without  any  considerable  change  in  the  degree  of  compression  to  which  the 
nervous  matter  is  subjected.  That  this  uniformity  is  of  the  greatest  importance 
to  the  functional  exercise  of  the  brain,  is  evident  from  a  few  well-known  facts. 
If  an  aperture  be  made  in  the  skull,  and  the  protruding  portion  of  the  brain  be 
subjected  to  pressure,  the  immediate  suspension  of  the  activity  of  the  whole  or- 
gan is  the  result ;  in  this  manner,  a  state  resembling  profound  sleep  can  be  in- 
duced in  a  moment,  the  normal  activity  being  renewed  as  momentarily  so  soon 
as  the  pressure  is  withdrawn.  This  phenomenon  has  often  been  observed  in  the 
Human  subject,  in  cases  in  which  a  portion  of  the  cranial  envelop  has  been  lost 
by  disease  or  injury.  The  various  symptoms  of  Cerebral  disturbance  which  are 
due  to  a  state  of  general  Plethora,  are  evidently  owing  to  an  excess  of  pressure 
within  the  vessels ;  but  an  undue  diminution  of  pressure  is  no  less  injurious, 
as  appears  from  the  disturbance  in  the  Cerebral  functions  which  results  from  the 
very  opposite  cause,  namely,  a  depression  of  the  power  of  the  heart,  or  a  defi- 
ciency of  blood  in  the  vessels. — It  is  of  peculiar  importance  to  bear  in  mind  the 
disturbance  of  the  Cerebral  functions,  which  is  occasioned  by  internal  pressure, 
when  we  are  endeavoring  to  draw  inferences  from  the  phenomena  presented  by 
disease. 

779.  We  shall  now  proceed  with  our  physiological  inquiry  into  the  functions 
of  the  Cerebrum ;  and  shall,  as  before,  apply  to  Human  and  Comparative  Ana- 
tomy, to  Experiment,  and  to  Pathology,  for  our  chief  data. — The  anatomical 
relations  of  the  Cerebrum  to  the  other  Encephalic  centres  clearly  demonstrate 
that  it  is  not  one  of  the  essential  or  fundamental  portions  of  the  Nervous  system ; 
but  a  superadded  organ,  receiving  all  its  impulses  to  action  from  the  parts  below, 
and  operating  upon  the  body  at  large  through  them.  And  its  great  bulk,  joined 
to  its  position  at  the  summit  of  the  whole  apparatus — the  vesicular  substance 
of  its  convolutions  affording  a  termination  to  the  fibres  in  connection  with  it, 
and  not  being  merely  traversed  by  them,  as  is  the  case  with  the  vesicular  sub- 
stance of  all  the  lower  centres — clearly  mark  it  out  as  the  highest  in  its  func- 
tional relations,  and  as  ministering,  so  far  as  any  material  instrument  may  do, 
to  the  exercise  of  those  psychical  powers  which,  in  Man,  exhibit  so  remarkable 
a  predominance  over  the  mere  animal  instincts.  This  conclusion  is  fully  borne 
out,  when  we  extend  our  inquiries  from  Human  to  Comparative  Anatomy ;  for 
with  some  apparent  exceptions,  which  there  would  probably  be  no  great  diffi- 
culty in  explaining  if  we  were  in  possession  of  all  the  requisite  data,  there  is  a 
very  close  correspondence  between  the  relative  development  of  the  Cerebrum  in 
the  several  tribes  of  Vertebrata,  and  the  degree  of  Intelligence  they  respectively 
possess — using  the  latter  term  as  a  comprehensive  expression  of  that  series  of 
mental  actions,  which  consists  in  the  intentional  adaptation  of  means  to  ends, 
based  on  definite  ideas  as  to  the  nature  of  both.  It  is  the  essential  character 
of  Instinctive  actions,  on  the  other  hand,  that  they  are  performed  automatically, 
in  obedience  to  internal  impulses,  without  even  the  perception  of  their  adapt- 
iveness  on  the  part  of  the  being  who  is  the  agent  in  them  ;  these  impulses  being 
called  into  play  by  impressions  on  the  nervous  system,  which  are  made  either 
by  external  objects,  or  by  changes  in  the  individual  organism.  The  justness  of 
this  distinction  becomes  obvious  when  we  analyze  our  own  consciousness,  and 
distinguish  our  own  Instinctive  actions  from  those  which  involve  Intelligence ; 
for  we  are  thus  led  to  perceive  that,  in  regard  to  those  operations  which  are  most 
closely  concerned  in  the  maintenance  of  our  own  lives  and  in  the  continuance 
of  the  race,  provision  has  been  made  in  the  mechanism  of  the  Automatic  por- 
tion of  our  nervous  system,  so  as  to  render  them  independent  of  the  exercise  of 
Intelligence  or  the  exertion  of  Will  on  our  own  parts.  Thus  the  infant  seeks  the 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  749 

nipple,  and  puts  its  muscles  into  suctorial  action,  without  any  knowledge  that 
by  so  doing  it  will  relieve  the  uneasy  feeling  of  hunger ;  and  if  we  could  imag- 
ine a  man  coming  into  the  world  with  the  full  possession  of  all  his  faculties, 
we  may  feel  tolerably  certain  that  he  would  not  wait  to  eat  until  he  had  learned 
by  experience  his  dependence  upon  food.  We  have  seen  that  adult  animals, 
whose  Cerebral  hemispheres  have  been  removed,  will  eat  food  that  is  put  into 
their  mouths  although  they  will  not  go  to  seek  it ;  and  this  is  the  case  with  many 
Human  idiots.  When  the  functions  of  the  Brain  are  disturbed,  or  in  partial 
abeyance,  as  in  fever,  we  often  see  a  remarkable  return  to  the  instinctive  pro- 
pensities in  regard  to  food ;  and  the  Physician  frequently  derives  important 
guidance  as  to  the  patient's  diet  and  regimen  (particularly  as  to  the  administration 
of  wine)  from  the  inclination  or  disinclination  which  he  manifests.  So,  in 
regard  to  the  intercourse  of  the  sexes,  the  impulse  which  prompts  to  it  does  not 
arise  from  a  knowledge  of  the  ultimate  purposes  which  it  is  designed  to  answer; 
and  the  higher  powers  of  the  mind  are  only  so  far  concerned  in  it  that,  when 
the  action  of  the  instinctive  impulse  has  led  to  the  formation  of  a  definite  idea 
of  the  object  of  desire,  the  Intelligence  is  prompted  to  take  means  for  its  grati- 
fication. 

780.  It  is  not  always  easy  to  say,  in  the  case  of  the  lower  animals,  what  parts 
of  their  actions  are  to  be  attributed  to  automatic  impulses  (i.  e.  to  be  considered 
as  Instinctive),  and  what  should  be  regarded  as  the  results  of  Intelligence.     In- 
stinctive actions,  however,  may  be  generally  distinguished  from  those  which  are 
directed  by  reason,   by  the  following   characters :   (1)  Their  unvarying  con- 
stancy in  the  different  individuals  of  the  same  species,  and  the  absence  of  any 
such  change,  during  the  progress  of  life  or  in  the  succession  of  generations,  as 
indicates  that  the  original  plan  of  action  has  been  intentionally  departed  from : 
(2)  by  their  occurrence  under  circumstances  which  altogether  forbid  the  idea 
that  any  past  experience  can  have  suggested  the  design,  or  that,  in  carrying  it 
into  effect,  there  has  been  a  gradual  perfectionizing  of  the  means :  these  actions 
being  performed  as  well  when  first  attempted,  as  after  the  most  frequent  repeti- 
tion :  (3)  by  their  occasional  performance  under  circumstances  in  which  the 
least  Intelligence  would  indicate  their  absurdity  as  being  nugatory  for  the  ends 
they  are  originally  destined  to  accomplish  :  as  when  a  tame  Beaver  attempts  to 
build  its  dam  across  a  room,  or  when  a  community  of  Bees,  having  killed  their 
Queen  because  she  only  lays  drone-eggs,  attempts  to  make  a  new  queen  from  one 
of  the  drone-larvae.     The  character  of  Intelligent  actions,  on  the  other  hand,  is 
shown  (1)  in  the  variety  of  means  which  may  be  adopted  to  compass  the  same 
ends,  and  this  not  merely  by  different  individuals  and  by  successive  generations, 
but  by  the  same  individual  at  different  times ;  (2)  by  the  improvement  in  the 
mode  of  accomplishing  the  object,  which  results  from  the  intelligent  use  of  ex- 
perience, and  from   the  greater  command  of  means  which  is  progressively  at- 
tained ;  and  (3)  by  the  conformity  of  the  means  to  altered  circumstances,  so 
that  the  character  of  adaptiveness  is  still  maintained,  however  widely  the  new 
conditions  may  depart  from  those  which  must  be  considered  as  natural  to  the 
species. 

781.  The  difference  between  actions  of  a  purely  Instinctive  character,  and 
those  which  proceed  from  the  Intellectual  faculties  prompted  by  the  instinctive 
propensities,  is  well  seen  in  comparing  Birds  with  Insects.     The  Instinctive 
tendencies  of  the  two  classes  are  of  nearly  the  same  kind;  and  the  usual  arts 
which  both  exhibit  in  the  construction  of  their  habitations,  in  procuring  their 
food,  and  in  escaping  from  danger,  must  be  regarded  as  intuitive,  on  account  of 
the  uniformity  with  which  they  are  practised  by  different  individuals  of  the 
same  species,  and  the  perfection  with  which  they  are  exercised  on  the  very  first 
occasion.     But  in  the  adaptation  of  their  operations  to  peculiar  circumstances, 
Birds  display  a  variety  and  fertility  of  resource  far  surpassing  that  which  ia 


750  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM.  , 

manifested  by  Insects ;  and  it  can  scarcely  be  doubted  by  those  who  attentively 
observe  their  habits  that  in  such  adaptations  they  are  often  guided  by  real 
Intelligence.  This  must  be  the  case,  for  example,  when  they  make  trial  of 
several  means,  and  select  that  one  which  best  answers  the  purpose;  or  when 
they  make  an  obvious  improvement  from  year  to  year  in  the  comforts  of  their 
dwelling;  or  when  they  are  influenced  in  the  choice  of  a  situation  by  peculiar 
circumstances,  which,  in  a  state  of  nature,  can  scarcely  be  supposed  to  eifect 
them.  The  complete  domesticability  of  many  Birds  is  in  itself  a  proof  of  their 
possessing  a  certain  degree  of  intelligence ;  but  this  alone  does  not  indicate  the 
possession  of  more  than  a  very  low  amount  of  it;  since  many  of  the  most  domes- 
ticable animals  are  of  the  humblest  intellectual  capacity,  and  seem  to  become 
attached  to  Man,  principally  as  the  source  on  which  they  depend  for  the  supply 
of  their  animal  wants.  But  there  are  certain  tribes  of  Birds,  especially  the 
Parrots  and  their  allies,  which  possess  an  extraordinary  degree  of  editcabitity, 
and  which  manifest  a  power  of  performing  simple  acts  of  reasoning,  that  are 
quite  comparable  with  those  of  a  child  when  first  learning  to  talk. — This  deve- 
lopment of  the  Intelligence  under  the  influence  of  Man,  and  in  accordance  with 
his  habits,  rather  than  with  the  original  habits  of  their  species,  is  yet  more  re- 
markable in  the  case  of  those  Mammals  whose  instincts  lead  them  to  attach 
themselves  peculiarly  to  him,  and  whose  powers  of  reasoning  are  called  forth  in 
adapting  themselves  to  the  new  circumstances  in  which  they  are  thus  placed. 
The  actions  of  a  Dog,  a  Horse,  or  an  Elephant  are  e'vidently  the  result,  in  many 
instances,  of  a  complex  train  of  reasoning,  differing  in  no  essential  respect  from 
that  which  Man  would  perform  in  similar  circumstances ;  so  that  the  epithet, 
"half-reasoning,"  commonly  applied  to  these  animals,  does  not  express  the  whole 
truth :  for  their  mental  processes  are  of  the  same  kind  with  those  of  Man,  and 
differ  more  in  the  degree  of  control  which  the  animal  possesses  over  them  than 
they  do  in  their  own  character.  We  have  no  evidence,  however,  that  any  of 
the  lower  animals  have  a  voluntary  power  of  guiding,  restraining,  or  accelerating 
their  mental  operations,  at  all  similar  to  that  which  Man  possesses;  these  opera- 
tions, indeed,  seem  to  be  of  very  much  the  same  character  as  those  which  we 
perform  in  our  dreams,  different  trains  of  thought  commencing  as  they  are  sug- 
gested, and  proceeding  according  to  the  usual  laws,  until  some  other  disturb 
them. — Although  it  is  customary  to  regard  the  Dog  and  the  Elephant  as  the 
most  intelligent  among  the  lower  animals,  it  is  not  certain  that  we  do  so  with 
justice;  for  it  is  very  possible  that  we  are  misled  by  that  peculiar  attachment 
to  Man,  which  in  them  must  be  termed  an  instinct,  and  which  enters  as  a  motive 
into  a  large  proportion  of  their  actions;  and  that,  if  we  were  more  acquainted 
with  the  psychical  characters  of  the  higher  Quadrumana,  we  should  find  in  them  a 
greater  degree  of  mental  capability  than  we  now  attribute  to  them.  One  thing 
is  certain,  that  the  higher  the  degree  of  intelligence  which  we  find  characteristic 
of  a  particular  race,  the  greater  is  the  degree  of  variation  which  we  meet  with 
in  the  characters  of  individuals;  thus  everybody  knows  that  there  are  stupid 
Dogs  and  clever  Dogs,  ill-tempered  Dogs  and  good-tempered  Dogs — as  there 
are  stupid  Men  and  clever  Men,  ill-tempered  Men  and  good-tempered  Men.  But 
no  one  could  distinguish  between  a  stupid  Bee  and  a  clever  Bee,  or  between  a 
good-tempered  Wasp  and  an  ill-tempered  Wasp,  simply  because  all  their  actions 
are  prompted  by  an  unvarying  instinct. 

782.  In  estimating  the  relative  development  of  the  Cerebrum  in  different 
tribes  of  Animals,  and  in  comparing  this  with  their  relative  Intelligence,  it 
must  be  borne  in  mind  that  the  size  of  the  organ  does  not,  considered  alone, 
afford  a  means  of  accurate  judgment  as  to  its  power.  For  the  quantity  of  vesi- 
cular matter  which  it  contains  affords  the  only  fair  criterion  of  the  latter;  and 
of  this  we  must  judge,  not  merely  by  the  superficial  area,  but  by  the  number 
and  depth  of  the  convolutions,  and  by  the  thickness  of  the  cortical  layer.  Again, 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  751 

there  are  many  reasons  why  it  is  not  fair  to  estimate  the  relative  develop- 
ment of  the  Cerebrum  by  the  proportion  which  it  bears  to  the  whole  bulk  of  the 
animal;  and,  on  the  whole,  the  most  accurate  basis  of  comparison  would  proba- 
bly be  afforded  by  the  relation  between  the  bulk  of  the  Cerebrum  and  the 
diameter  of  the  Spinal  Cord.  In  making  any  such  comparison,  however,  the 
Thalami  Optici,  Corpora  Striata,  and  Corpora  Quadrigemina  should  be  excluded 
from  the  estimate,  for  reasons  now  sufficiently  apparent;  and  the  bulk  of  the 
Cerebrum  proper  should  be  alone  determined,  either  by  weight,  or  by  the  dis- 
placement of  liquid. — But  the  Cerebrum  varies  in  different  classes  and  orders 
of  Vertebrata,  not  merely  in  proportional  size,  but  also  in  the  relative  develop- 
ment of  its  anterior,  middle,  and  posterior  lobes.  This  is  a  point  of  very  great 
importance  in  determining  the  value  to  be  assigned  to  the  organological  system 
of  Gall  and  Spurzheim  and  their  followers.  The  Cerebrum  of  the  Oviparous 
Vertebrata  is  not  a  miniature  representative  of  that  of  Man,  as  a  whole,  but  only 
of  his  anterior  lobes;  as  is  sufficiently  obvious  from  an  examination  of  its  con- 
nections with  other  parts,  and  from  the  absence  of  any  other  commissural  con- 
nections between  its  two  hemispheres,  than  those  which  are  afforded  by  the 
Sensory  Ganglia.  It  is  in  the  Implacental  Mammals  that  we  find  the  first  rudi- 
ment of  the  middle  lobes  of  the  Cerebrum,  and  of  the  proper  intercerebral  com- 
missure, the  Corpus  Callosum;  and  even  in  the  Rodents  this  is  but  very 
imperfectly  developed.  As  we  ascend  the  Mammalian  series,  we  find  the 
Cerebrum  becoming  more  and  more  elongated  posteriorly  by  the  development 
of  the  middle  lobes,  and  the  intercerebral  commissure  becomes  more  complete; 
but  we  must  ascend  as  high  as  the  Carnivora  before  we  find  the  least  vestige  of 
the  posterior  lobes ;  and  the  rudiment  which  these  possess,  and  which  is  enlarged 
in  the  Quadrumana,  only  attains  its  full  development  in  man,  in  whom  alone 
the  posterior  lobes  extend  so  far  backwards,  as  completely  to  cover  in  the  Cere- 
bellum.1— The  attention  which  has  yet  been  given  to  this  department  of  inquiry 
has  not  hitherto  done  more  than  confirm  the  statement  already  made  with  regard 
to  the  general  correspondence  between  the  development  of  the  Cerebrum  and 
the  manifestations  of  Intelligence ;  very  decided  evidence  of  which  is  furnished 
by  the  great  enlargement  of  the  Cerebrum,  and  the  corresponding  alteration  in 
the  form  of  the  Cranium,  which  present  themselves  in  those  races  of  Dogs  most 
distinguished  for  their  educability,  when  compared  with  those  whose  condition 
approximates  most  closely  to  what  was  probably  their  original  state  of  wildness. 
783.  This  general  inference,  drawn  from  Comparative  Anatomy,  is  borne  out 
by  observation  of  the  Human  species.  When  the  Cerebrum  is  fully  developed, 
it  offers  innumerable  diversities  of  form  and  size  among  various  individuals  ;  and 
there  are  as  many  diversities  of  character.  It  may  be  doubted  if  two  individuals 
were  ever  exactly  alike  in  this  respect.  That  a  Cerebrum  which  is  greatly  un- 
der the  average  size  is  incapable  of  performing  its  proper  functions,  and  that 
the  possessor  of  it  must  necessarily  be  more  or  less  idiotic,  there  can  be  no  rea- 
sonable doubt.  On  the  other  hand,  that  a  large  well-developed  Cerebrum  is 
found  to  exist  in  persons  who  have  made  themselves  conspicuous  in  the  world  in 

1  It  lias  been  asserted  by  the  followers  of  Gall  that  the  development  of  the  Cerebrum 
from  behind  forwards,  as  above  described,  is  rather  apparent  than  real ;  the  whole  organ 
being  in  fact  pushed  backwards  by  the  excessive  development  of  the  anterior  lobe.  But 
the  anatomical  distinction  between  the  anterior  and  middle  lobes  is  sufficiently  obvious 
externally ;  and  that  of  the  middle  and  posterior  lobes  is  also  clearly  marked  out  by  the 
development  of  the  posterior  cornua  of  the  lateral  ventricles,  and  the  situation  of  the  hip- 
pocampus major.  Hence  the  facts  above  stated  do  not  admit  of  any  such  interpretation ; 
and  they  are  fully  borne  out  by  the  history  of  the  Embryonic  development  of  the  Cerebrum 
in  Man,  which  precisely  follows  the  above  plan. — It  is  not  here  denied  that  the  anterior 
lobe  of  the  Human  Cerebrum  is  remarkable  for  its  great  extension  forwards  ;  but  still,  the 
difference  between  the  Cerebrum  of  Man  and  that  of  the  lower  Mammalia  consists  much 
rather  in  the  proportional  development  of  the  posterior  lobes  than  in  that  of  the  anterior. 


752  OF   THE   FUNCTIONS    OF   THE    NERVOUS    SYSTEM. 

virtue  of  their  intellectual  achievements,  may  be  stated  as  a  proposition  of 
equal  generality.  In  these  opposite  cases,  we  witness  most  distinctly  the  anta- 
gonism between  the  Instinctive  and  Voluntary  powers.  Those  unfortunate 
beings,  in  whom  the  Cerebrum  is  but  little  developed,  are  guided  almost  solely 
by  their  instinctive  tendencies ;  which  frequently  manifest  themselves  with  a 
degree  of  strength  that  would  not  have  been  supposed  to  exist :  and  occasionally 
new  instincts  present  themselves,  of  which  the  Human  being  is  ordinarily  re- 
garded as  destitute.1  On  the  other  hand,  those  who  have  obtained  most  in- 
fluence over  the  understandings  of  others  have  always  been  large-brained  per- 
sons, of  strong  intellectual  and  volitional  powers,  whose  emotional  tendencies 
have  been  subordinated  to  the  reason  and  will,  and  who  have  devoted  their 
whole  energy  to  the  particular  objects  of  their  pursuit. — It  is  very  different, 
however,  with  those  who  are  actuated  by  what  is  ordinarily  termed  genius  ;  and 
whose  influence  is  rather  upon  the  feelings  and  intuitions,  than  upon  the  under- 
standings of  others.  Such  persons  are  often  very  deficient  in  the  power  of  even 
comprehending  the  ordinary  affairs  of  life  ;  and  still  more  commonly,  they  show 
an  extreme  want  of  judgment  in  the  management  of  them,  being  under  the  im- 
mediate influence  of  their  passions  and  emotions,  which  they  do  not  sufficiently 
endeavor  to  control  by  their  intelligent  will.  The  life  of  a  "  genius,"  whether 
his  bent  be  towards  poetry,  music,  painting,  or  pursuits  of  a  more  material  cha- 
racter, is  seldom  one  which  can  be  held  up  for  imitation.  In  such  persons,  the 
general  power  of  the  mind  being  low,  the  Cerebrum  is  not  usually  found  of  any 
great  size. — The  mere  comparative  size  of  the  Cerebrum,  however,  affords  no  ac- 
curate measure  of  the  amount  of  mental  power  :  we  not  unfrequently  meet  with 
men  possessing  large  and  well-formed  heads  ;  whilst  their  physical  capability  is 
not  greater  than  that  of  others,  the  dimensions  of  whose  crania  have  the  same 
general  proportion,  but  are  of  much  less  absolute  size.  Large  brains,  with  de- 
ficient activity,  are  commonly  found  in  persons  of  what  has  been  termed  the 
phlegmatic  temperament,  in  whom  the  general  processes  of  life  seem  in  a  torpid 
and  indolent  state;  whilst  small  brains  and  great  activity  betoken  what  are 
known  as  the  sanguine  and  nervous  temperaments. 

784.  Having  now  inquired  into  the  evidence  of  the  general  functions  of  the 
Cerebrum,  which  may  be  derived  from  examination  of  its  Comparative  develop- 
ment, we  proceed  to  our  other  sources  of  information,  Experiment  and  Patho- 
logical phenomena.  From  neither  of  these,  however,  is  much  positive  informa- 
tion to  be  derived. — The  results  of  partial  mutilations  are  usually,  in  the  first 
instance,  a  general  disturbance  of  the  Cerebral  functions ;  which  subsequently, 
however,  more  or  less  subsides,  leaving  but  little  apparent  affection  of  the  ani- 
mal functions,  except  muscular  weakness.  The  whole  of  one  Hemisphere  has 
been  removed  in  this  way  without  any  evident  consequence,  save  a  temporary 
feebleness  of  the  limbs  on  the  opposite  side  of  the  body,  and  what  was  supposed 
to  be  a  deficiency  of  sight  through  the  opposite  eye.  The  former  was  speedily 
recovered  from,  and  the  animal  performed  all  its  movements  as  well  as  before  ; 
the  latter,  however,  was  permanent,  but  the  pupil  remained  active.  When  the 
upper  part,  only,  of  both  Cerebral  Hemispheres  was  removed  by  Hertwig,  the 
animal  was  reduced,  for  fifteen  days,  to  nearly  the  same  condition  with  the  one 
from  which  they  had  been  altogether  withdrawn ;  but,  afterwards,  sensibility 
evidently  returned,  and  the  muscular  power  did  not  appear  to  be  much  dimi- 
nished.— The  effects  of  the  entire  removal  of  the  Cerebral  Hemispheres  have 
been  already  stated  (§  734).  So  far  as  any  inferences  can  be  safely  drawn  from 

1  A  remarkable  instance  of  this  was  published  some  years  since. — A  perfectly  idiotic 
girl,  in  Paris,  having  been  seduced  by  some  miscreant,  was  delivered  of  a  child  without 
assistance  ;  and  it  was  found  that  she  had  gnawed  the  umbilical  cord  in  two,  in  the  same 
manner  as  is  practised  by  the  lower  animals.  It  is  scarcely  to  be  supposed  that  she  had 
any  idea  of  the  object  of  this  separation. 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  753 

them,  these  fully  bear  out  the  conclusion  that  the  Cerebrum  is  the  organ  of  In- 
telligence ;;  since  the  animals  which  have  suffered  this  mutilation  appear  to  be 
constantly  plunged  in  a  profound  sleep,  from  which  no  irritation  ever  seems 
able  to  arouse  them  into  full  activity,  although  they  give  manifestations  of  con- 
sciousness. It  would  be  wrong  hence  to  infer,  however,  as  some  have  done, 
that  such  would  be  the  natural  condition  of  an  animal  without  a  Cerebrum ; 
since  it  is  obvious  that  much  of  the  disturbance  of  the  sensorial  powers  which  is 
occasioned  by  this  operation,  is  fairly  attributable  to  the  laying-open  of  the 
cranial  cavity,  to  the  disturbance  of  the  normal  vascular  pressure,  and  to  the 
injury  necessarily  done  to  the  parts  which  are  left,  by  their  severance  from  the 
Cerebrum.  Hence  the  persistence  of  consciousness,  after  the  entire  removal  of 
the  Cerebrum — which  proves  that  the  Cerebrum  is  not  its  seat,  or  at  least  not 
its  exclusive  seat — is  a  far  more  important  fact  than  the  positive  destruction  of 
psychical  power  which  is  consequent  upon  the  operation.  So  far  as  they  can  be 
trusted,  however,  the  results  of  such  mutilations  bear  out  the  views  already  put 
forth  as  to  the  superadded  and  non-essential  character  of  the  Cerebrum ;  and 
justify  us  in  applying  to  the  higher  animals  the  inferences  to  which  we  should 
be  led  by  the  contemplation  of  those  forms  of  the  nervous  system  in  which  no 
Cerebrum  exists.  There  is  nothing,  therefore,  to  oppose  the  conclusion,  that 
whilst  sensations  may  be  felt,  and  sensori-motor  actions  excited,  independently 
of  the  Cerebrum,  the  presence  of  this  organ  is  essential  to  the  formation  of 
ideas  or  notions  respecting  the  objects  of  sense,  and  to  the  performance  of  those 
psychical  operations  to  which  ideas  furnish  at  once  the  material  and  the  stimu- 
lus to  activity.1 

785.  The  information  afforded  by  Pathological  phenomena  is  equally  far  from 
being  definite.  Many  instances  are  on  record,  in  which  extensive  disease 
has  occurred  in  one  Hemisphere,  so  as  almost  entirely  to  destroy  it,  without 
either  any  obvious  injury  to  the  mental  powers,  or  any  interruption  of  the  in- 
fluence of  the  mind  upon  the  body.  But  there  is  no  case  on  record,  of  any 
such  severe  lesions  of  both  hemispheres,  in  which  morbid  phenomena  were  not 
evident  during  life.  It  is  true  that,  in  Chronic  Hydrocephalus,  a  very  remark- 
able alteration  in  the  condition  of  the  Brain  sometimes  presents  itself,  which 
might  a  priori  have  been  supposed  destructive  to  its  power  of  activity ;  the 
ventricles  being  so  enormously  distended  with  fluid,  that  the  cerebral  matter  has 
seemed  like  a  thin  lamina,  spread  over  the  interior  of  the  enlarged  cranium. 
But  there  is  no  proof  that  absolute  destruction  of  any  part  was  thus  occasioned  ; 
and  it  would  seem  that  the  very  gradual  nature  of  the  change  gives  to  the 
structure  time  for  accommodating  itself  to  it.  This,  in  fact,  is  to  be  noticed  in 
all  diseases  of  the  Encephalon.  A  sudden  lesion,  that  may  be  so  trifling  as  to 
escape  observation,  unless  this  be  very  carefully  conducted,  will  occasion  very 
severe  symptoms ;  whilst  a  chronic  disease  may  gradually  extend  itself,  without 
any  external  manifestation.  It  will  usually  be  found  that  sudden  paralysis,  of 
which  the  seat  is  in  the  Brain,  results  from  some  slight  effusion  of  blood  in  the 
substance  or  in  the  neighborhood  of  the  Corpora  Striata ;  whilst,  if  it  follow 
disorder  of  long  standing,  a  much  greater  amount  of  lesion  will  usually  present 
itself.  In  either  case,  the  paralysis  occurs  in  the  opposite  side  of  the  body,  as 
we  should  expect  from  the  decussation  of  the  Pyramids ;  but  it  may  occur  either 
on  the  same,  or  on  the  opposite  side  of  the  face — the  cause  of  which  is  not  very 
apparent.  If  convulsions  accompany  the  paralysis,  we  may  infer  that  the  Cor- 
pora Quadrigemina,  or  the  parts  below,  are  involved  in  the  injury;  and  in  this 

1  It  is  worthy  of  remark,  that  M.  Flourens,  who  in  the  first  instance  maintained  that 
sensation  is  altogether  destroyed  by  the  removal  of  the  Cerebrum,  has  substituted,  in  the 
Second  Edition  of  his  Researches,  the  word  perception  for  sensation;  apparently  implying 
exactly  what  is  maintained  above. 
48 


754  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

case  it  is  usually  found  that  the  convulsions  are  on  the  paralyzed  side  of  the  body 
— the  effect  of  the  lesion,  both  of  the  Cerebrum  and  of  the  Corpora  Quadrige- 
mina,  being  propagated  to  the  opposite  side,  by  the  decussation  of  the  Pyramids. 
Where,  as  not  unfrequently  happens,  there  is  paralysis  of  one  side,  accompanying 
convulsions  on  the  other,  it  is  commonly  the  result  of  a  lesion  affecting  the  base 
of  the  Brain  and  Medulla  Oblongata,  on  the  side  on  which  the  convulsions  take 
place ;  here  the  effect  of  the  lesion  has  to  cross  from  the  Brain,  whilst  its  influence 
on  the  Medulla  Oblongata  is  shown  on  the  same  side.  Many  anomalies  present 
themselves,  however,  which  are  by  no  means  easy  of  explanation,  in  the  present 
state  of  our  knowledge. — The  disturbance  of  the  Cerebral  functions,  occasioned 
by  those  changes  in  its  nutrition  which  are  commonly  included  under  the  general 
term  of  Inflammation,  presents  a  marked  diversity  of  character,  according  to  the 
part  it  affects.  Thus  it  is  well  known  that  the  delirium  of  excitement  is  usually 
a  symptom  of  inflammation  of  the  cortical  substance,  or  of  the  membranes  of  the 
hemispheres.  This  is  exactly  what  might  be  anticipated  from  the  foregoing 
premises,  since  this  condition  is  a  perversion  of  the  ordinary  mental  operations, 
which  are  dependent  upon  the  instrumentality  of  the  vesicular  matter  :  and  it  is 
evidently  impossible  for  the  membranes  to  be  affected  with  inflammation,  without 
the  nutrition  of  this  substance  being  impaired,  since  it  derives  all  its  vessels 
directly  from  them.  On  the  other  hand,  inflammation  of  the  fibrous  portion  of 
the  Cerebrum  is  usually  attended  rather  with  a  state  of  torpor,  than  with  excite- 
ment ;  and  with  diminished  power  of  the  will  over  the  muscles.  It  is  stated 
by  Foville,  that  in  acute  cases  of  Insanity,  he  has  usually  found  the  cortical 
substance  intensely  red,  but  without  adhesion  to  the  membranes ;  whilst  in 
chronic  cases,  it  is  indurated  and  adherent :  but  where  the  insanity  has  been 
complicated  with  Paralysis,  he  has  usually  found  the  medullary  portion  indu- 
rated and  congested. 

786.  The  general  result  of  such  investigations  is,  that  the  Cerebrum  is  the 
instrument  of  all  those  psychical  operations,  which  we  include  under  the  general 
term  Intellectual,  whilst  it  also  affords,  in  part  at  least,  the  instrumental  condi- 
tions of  Emotional  states  (using  this  term  in  its  widest  sense) ;  and  that  all  those 
muscular  movements  which  result  from  voluntary  determinations,  or  which  are 
directly  consequent  upon  emotional  excitement,  have  their  origin  in  its  vesicular 
substance,  though  the  motor  impulse  is  immediately  furnished  by  the  Automatic 
apparatus,  upon  which  the  Cerebrum  plays  (§  757). — All  the  operations  of  the 
Mind  are  originally  dependent  upon  the  reception  of  Sensations.  If  it  were 
possible  for  a  Human  being  to  come  into  the  world,  with  a  Brain  perfectly  pre- 
pared to  be  the  instrument  of  psychical  operations,  but  with  all  the  inlets  to 
sensation  closed,  we  have  every  reason  to  believe  that  the  Mind  would  remain 
dormant,  like  a  seed  buried  deep  in  the  earth.  The  attentive  study  of  cases,  in 
which  there  is  congenital  deficiency  of  one  or  more  sensations,  makes  it  evident 
that  the  Mind  is  utterly  incapable  of  forming  any  definite  ideas  in  regard  to 
those  properties  of  objects  of  which  those  particular  sensations  are  adapted  to 
take  cognizance.  Thus  the  man  who  is  born  blind  can  form  no  conception  of 
color ;  nor  the  congenitally  deaf,  of  musical  tones.  And  in  those  lamentable 
cases,  in  which  the  sense  of  touch  is  the  only  one  through  which  ideas  can  be 
introduced,  it  is  evident  that  the  mental  operations  must  remain  of  the  simplest 
and  most  limited  character,  if  the  utmost  attention  be  not  given,  by  a  judicious 
instructor,  to  the  development  of  the  intellectual  faculties,  and  the  cultivation 
of  the  moral  feelings,  through  that  restricted  class  of  ideas  which  there  is  a  pos- 
sibility of  exciting. — The  activity  of  the  Mind,  then,  is  just  as  much  the  result 
of  its  consciousness  of  external  impressions,  by  which  its  faculties  are  called  into 
play,  as  the  Life  of  the  body  is  dependent  upon  the  appropriation  of  nutrient 
materials,  and  the  constant  influence  of  external  forces.  But  there  is  this  dif- 
ference between  the  two  cases — that  whilst  the  Body  continually  requires  new 


THE   CEREBRUM,    AND   ITS    FUNCTIONS.  755 

materials  and  a  continued  action  of  external  agencies,  the  Mind,  when  it  has 
been  once  called  into  activity,  and  has  become  stored  with  ideas,  may  remain 
active,  and  may  develop  new  relations  and  combinations  amongst  these,  after 
the  complete  closure  of  the  sensorial  inlets  by  which  new  ideas  can  be  excited 
ah  externo.  Such  is,  in  fact,  what  is  continually  going  on  in  the  state  of  Dream- 
ing; but  examples  yet  more  remarkable  are  furnished  in  the  vivid  conceptions 
which  may  be  formed  of  a  landscape  or  a  picture,  from  oral  description,  by 
those  who  have  once  enjoyed  sight;  or  in  the  composition  of  music,  even  such 
as  involves  new  combinations  of  sounds,  by  those  who  have  become  deaf — as  in 
the  well-known  case  of  Beethoven.  The  mind  thus  feeds,  as  it  were,  upon  the 
store  which  has  been  laid  up  during  the  activity  of  its  sensory  organs ;  but 
instead  of  diminishing,  like  material  food,  these  ideas  become  more  and  more 
vivid,  the  oftener  they  are  made  the  subjects  of  attention. 

787.  The  seat  of  the  Sensational  Consciousness,  as  already  shown,  is  indicated 
by  a  large  mass  of  evidence  to  lie  in  the  Sensory  Ganglia,  which  are  the  real 
centres  of  the  Nerves  of  Sense ;  and  we  may  fairly  conclude  that,  when  not  in- 
terrupted in  the  upward  course  already  indicated,  the  changes  which  occur  there 
give  rise  to  a  new  excitement  of  nerve-force,  which  is  propagated  along  the  as- 
cending nerve-fibres  to  the  vesicular  matter  that  forms  the  surface  of  the  Cerebral 
Hemispheres;  and  that  it  is  only  when  they  arrive  at  the  ultimate  termination 
of  these  fibres  in  the  latter,  that  these  impressions  give  rise  to  those  changes 
which  are  in  the  first  instance  instrumental  in  the  formation  of  Ideas1  and  sub- 
sequently in  the  higher  Intellectual  Operations.  These  operations  themselves 
become  the  source  of  new  changes  in  the  condition  of  the  Nervous  substance ; 
and  an  excitation  of  nerve-force  takes  place  as  their  result,  which,  transmitted 
downwards  to  the  sensorial  tract  at  the  base  of  the  Cerebrum,  gives  rise  through 
it  to  respondent  movements  (§  759). — Now  it  is  an  inquiry  of  considerable  in- 
terest, both  in  its  psychological  and  its  physiological  relations,  whether  the 
Cerebrum  is  itself  endowed  with  consciousness ;  that  is,  whether  we  become 
conscious  of  changes  which  take  place  in  the  condition  of  its  substance,  so  long 
as  these  changes  are  limited  to  itself.  At  first  sight  it  would  appear  to  be  a 
very  startling  proposition,  that  the  organ  of  the  intellectual  operations  is  not 
itself  endowed  with  consciousness ;  but  a  careful  consideration  of  its  relations 
to  the  Sensory  Ganglia  will  tend  to  show  that  there  is  no  d  priori  absurdity  in 
such  a  notion.  For,  if  the  relation  of  the  vesicular  matter  of  the  Cerebral 
Hemispheres  to  the  Sensorial  Centres,  be  anatomically  the  same  as  that  which 
is  borne  to  these  centres  by  the  Retina,  or  by  any  other  peripheral  expansion  of 

1  The  Author  cannot  here  enter  into  the  discussion  which  has  been  the  subject  of  so 
many  abstruse  and  labored  Metaphysical  discussions,  how  far  Ideas  are  to  be  considered 
as  "  transformed  sensations,"  or  as  "  states  or  affections  of  the  consciousness"  which, 
though  primarily  excited  by  sensations,  may  have  nothing  in  common  with  them.  It  will 
be  sufficient  for  him  to  express  his  own  conviction,  that  the  latter  is  the  only  consistent 
mode  of  viewing  the  subject ;  and  that  the  Idea  can  no  more  correctly  be  described  as  a 
"  transformed  sensation,"  than  sensation  itself  could  be  designated  as  a  transformed  im- 
pression. The  one  is  antecedent,  the  other  consequent ;  the  one  is  the  force  which,  acting 
on  a  certain  prepared  organization,  evokes  a  further  change,  just  as  a  mechanical  or  elec- 
trical stimulus  applied  to  a  muscle  calls  it  into  contraction. — The  notion  of  Condillac  and 
the  Sensational  School  of  Psychologists,  that  ideas  are  "  transformed  sensations,"  appears 
to  have  been  based  upon  the  consideration  of  those  ideas  alone  which  are  most  nearly  allied 
to  Sensations  in  their  nature,  being  the  immediate  psychical  representations  of  objective 
or  concrete  realities.  But  it  cannot  be  legitimately  held  of  those  abstract  or  general  ideas, 
which  have  no  objective  representatives,  and  which  are  the  products  of  mental  operations 
that  are  by  no  means  truly  described  by  the  term  transformation.  Thus  the  idea  of  the 
invariability  of  the  laws  of  Nature  arises  out  of  a  constant  succession  of  new  and  diversified 
phenomena;  as  has  been  beautifully  shown  by  Prof.  Oersted,  in  his  Essay  on  "  The  Spirit- 
ual in  the  Material,"  which  forms  the  first  section  of  his  Treatise  on  "  The  Soul  in  Nature," 
recently  ^iven  to  the  English  public. 


756 


OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 


vesicular  matter  in  an  organ  of  sense,  which  we  have  seen  that  it  is  (§  753), 
— and  if  the  same  kind  of  change  may  be  excited  in  the  Sensorial  Centres  by 
an  impression  from  each  source,  which  has  been  shown  to  be  a  matter  of  common 
occurrence  (§  758) — it  can  scarcely  be  deemed  unlikely  that  the  Sensorial  Centres 
should  be  the  seat  of  consciousness,  not  merely  of  the  impressions  transmitted 

Fig.  195. 


Diagram  of  the  mutual  relations  of  the  principal  Encephalic  centres  as  shown  in  a  vertical  section :  A, 
Cerebrum ;  B,  Cerebellum ;  c,  Sensori-motor  tract,  including  the  Olfactive  ganglion  olf,  the  Optic  opt,  and  the 
Auditory  aud,  with  the  Thalami  Optici  thai,  and  the  Corpora  Striata  cs;  D,  Medulla  Oblongata;  E,  Spinal 
Cord:  a,  olfactive  nerve;  ft,  optic;  c,  auditory;  d,  pneumogastric  ;  e,  hypoglossal;  /,  spinal:  fibres  of  the 
medullary  substance  of  the  cerebrum  are  shown,  connecting  its  ganglionic  surface  with  the  sensori-motor 
tract. 

to  them  by  the  nerves  of  the  external  senses,  but  also  of  the  impressions  brought 
to  them  by  the  "  nerves  of  the  internal  senses  ;"  as  the  sagacious  Keil  desig- 
nated the  radiating  fibres  of  the  Cerebral  Hemispheres.  And  there  is  on  the 
other  hand  an  d  priori  improbability  that  there  should  be  two  seats  of  conscious- 
ness, so  far  removed  from  one  another  as  the  Sensory  Ganglia  and  the  vesicular 
surface  of  the  Hemispheres  (for  to  their  medullary  substance  no  such  attribute 
can  be  assigned  with  the  least  probability) ;  an  idea  which  is  quite  at  variance 
with  that  very  simple  and  familiar  class  of  phenomena  which  consists  in  the 
recollection  of  sensations.  For  the  remembered  sensation  is  so  completely 
the  repetition  of  the  original,  that  we  can  hardly  suppose  the  seat  of  the  two 
to  be  different ;  yet  the  act  of  recollection  is  clearly  Intellectual,  and  therefore 
Cerebral ;  consequently  if  we  admit  that  the  Sensory  Ganglia  are  the  seat  of  the 
original  sensation,  we  can  scarcely  but  admit  that  they  are  also  the  seat  of  that 
which  is  reproduced  by  a  Cerebral  act — a  view  which  is  fully  confirmed  by  the 

1  It  is  interesting  to  observe  how  remarkably  this  view  is  confirmed  by  the  history  of 
Development.  For  the  Retina,  like  the  cortical  substance  of  the  Cerebrum,  is  a  vesicular 
expansion  originally  detached  from  the  Sensory  Ganglia,  and  gradually  carried  to  a  greater 
and  greater  distance  from  them ;  but  still  remaining  connected  by  the  commissural  tract 
of  white  fibres,  which  we  call  in  the  one  case  the  Optic  Nerve,  and  in  the  other  the  Me- 
dullary substance  of  the  Hemispheres. 


THE    CEREBRUM,    AND   ITS   FUNCTIONS.  757 

occurrence  of  automatic  movements  as  consequences  of  its  recall  (§  758).  But 
farther,  we  shall  hereafter  find  evidence  to  the  same  effect,  in  our  experience  of 
the  occasional  evolution  of  results  such  as  ordinarily  proceed  from  intellectual 
action,  without  any  consciousness  on  our  own  parts  of  the  steps  whereby  these 
are  attained  (§§  813,  819,  820). 

788.  Without  presuming,  then,  to  affirm  positively  what  cannot  be  proved, 
it  may  be  stated  as  a  probable  inference  from  the  Physiological  facts  already 
referred  to,  and  from  the  Psychological  evidence  hereafter  to  be  adduced,  that 
the  Sensory  Ganglia  constitute  the  seat  of  consciousness,  not  merely  for  impres- 
sions on  the  Organs  of  Sense,  but  also  for  changes  in  the  cortical  substance  of 
the  Cerebrum;  so  that,  until  the  latter  have  reacted  downwards  upon  the  Sen- 
sorium,  we  have  no  consciousness  either  of  the  formation  of  ideas,  or  of  any  intel- 
lectual process  of  which  these  may  be  the  subjects.     Ideas,  emotions,  intellectual 
operations,  &c.,  have  of  late  been  frequently  designated  as  "states  of  conscious- 
ness;" and  this  psychological  description  of  them  is  in  full  harmony  with  the 
physiological  account  here  given  of  the  material  conditions  under  which  they 
respectively  occur.      For  a  Sensation  being  a  state  of  consciousness  excited 
through  the  intermediation  of  the  Sensorium,  by  a  certain  change  (e.  </.)  in  the 
condition  of  the  Retina,  it  is  not   difficult  to  understand  how  a  change  in  the 
condition  of  the  Cerebrum  may  excite,  through  the  same  instrumentality,  that 
state   of  consciousness  which  may  be   termed   Ideational,1   or   that   another 
change   may  produce   the   Emotional  Consciousness,    another  the  Intuitional 
Consciousness,  another  the  Logical  Consciousness.     And  although  it  may  be 
thought  at  first  sight  to  be  a  departure  from  the  simplicity  of  Nature,  to  sup- 
pose that  the  Cerebrum  should  require  another  organ  to  give  us  a  consciousness 
of  its  operations,  yet  we  have  the  knowledge  that  the  Eye  does  not  give  us 
visual  consciousness,  nor  the  Ear  auditory  consciousness,  unless  they  be  con- 
nected with  the  Sensory  Ganglia ;  and  in  the  end  (the  Author  feels  a  strong  as- 
surance) it  will  be  found  much  simpler  to  accept  the  doctrine  of  a  common  centre 
for  sensational  and  for  what  may  be  distinguished  as  mental  consciousness,  than 
to  regard  the  two  centres  as  distinct.53 — We  shall  now  proceed  with  a  brief  ana- 
lysis of  the  operations  of  which  the  Cerebrum  is  the  instrument ;  considering 
them  in  the  ascending  series,  as  founded  upon  Sensational  changes. 

789.  Neither  the  operation  of  the  Intellectual  Powers,  nor  Emotional  excite- 
ment is  immediately  called  forth  by  the  Sensational  Consciousness ; 'for  if  we 
do  not  advance  beyond  this,  we  merely  recognize  the  fact  that  certain  changes 
have  occurred  in  our  own  ll  subjective"  state,  and  do  not  refer  these  changes  to 
any  external  or  t(  objective"  source.     Of  this  we  occasionally  meet  with  ex- 
amples among  the  phenomena  of  dreaming,  and  in  some  of  the  conditions  re- 
sulting from  the  use  of  Anaesthetic  agents ;  for  if  we  fall  asleep  whilst  suffering 
from  bodily  pain,  we  may  entirely  lose  all  perception  of  the  cause  of  that  pain 
as  having  its  seat  in  our  own  bodily  fabric,  and  yet  remain  conscious  of  a  per- 
turbed state  of  feeling;  and  when  a  surgical  operation  is  performed  in  a  state 
of  incomplete  Anaesthesia,  it  is  obvious  that  pain  is  felt  without  any  distinct 

1  The  Author  ventures  to  use  this  term,  the  meaning  of  which  requires  no  explanation, 
on  the  authority  of  Mr.  James  Mill,  who  remarks:  "As  we  say  Sensation,  we  might  also 
say  Ideation ;  it  would  be  a  very  useful  word  ;  and  there  is  no  objection  to  it,  except  the 
pedantic  habit  of  decrying  a  new  term.     Sensation  is  the  general  name  for  one  part  of 
our  constitution  [or  rather,  for  one  state  of  our  consciousness],  Ideation  for  another." 
("  Analysis  of  the  Human  Mind,"  vol.  i.  p.  42.) — If  the  use  of  the  substantive  Ideation 
be  admitted,  there  can  be  no  reasonable  objection  to  the  adjective  ideational. 

2  It  may  serve  to  give  additional  confidence  in  the  views  above  propounded,  if  the  Author 
mentions  that  he  was  led  by  them  to  predict  the  psychological  phenomena  referred  to  at 
the  end  of  \  787,  of  which  he  was  not  at  the  time  aware  as  facts,  but  of  which  he  after- 
wards became  assured  by  the  analysis  of  his  own  consciousness,  and  by  the  communicated 
experience  of  others  to  whom  he  stated  the  question. 


758  OF   THE   FUNCTIONS   OF   THE    NERVOUS    SYSTEM. 

consciousness  of  its  source,  and  the  patient  may  subsequently  describe  his  state 
as  an  uneasy  dream.  Such,  it  is  probable,  is  the  condition  of  the  Infant  at  the 
commencement  of  its  psychical  life.  "  If,"  as  has  been  well  remarked  by  Mr. 
Morell,1  "  we  could  by  any  means  transport  ourselves  into  the  mind  of  an  infant 
before  the  perceptive  consciousness  is  awakened,  we  should  find  it  in  a  state  of 
absolute  isolation  from  everything  else  in  the  world  around  it.  Whatever  objects 
may  be  presented  to  the  eye,  the  ear,  or  the  touch,  they  are  treated  simply  as 
subjective  feelings,  without  the  mind's  possessing  any  consciousness  of  them  as 
objects  at  all.  To  it,  the  inward  world  is  everything,  the  outward  world  is 
nothing." — However  difficult  it  may  be,  under  the  influence  of  our  life-long 
experience,  to  dissociate  any  sensation  which  we-  experience  from  the  idea  of  its 
external  cause — since,  the  moment  the  feeling  is  experienced,  and  the  mind  is 
directed  to  it,  the  object  from  which  it  arises  is  immediately  suggested — yet 
nothing  is  more  certain  than  that  all  of  which  we  are  ourselves  conscious,  in 
any  case  whatever,  is  a  certain  internal  or  subjective  state,  a  change  in  our  pre- 
vious consciousness  ;  and  that  the  formation  of  the  idea  of  the  object  to  which 
that  change  is  due,  is  dependent  upon  a  higher  mental  process,  to  which  the 
name  of  Perception  or  Perceptive  Consciousness  is  now  generally  accorded.2 
We  may  recognize  the  manifestation  of  this  process  in  the  child,  as  it  advances 
beyond  the  first  few  months  of  its  helplessness.  "  A  sight  or  a  sound/'  remarks 
Mr.  Morell  (Op.  cit.),  "which  at  first  produced  simply  an  involuntary  start,  now 
awakens  a  smile  or  a  look  of  recognition.  The  mind  is  evidently  struggling  out 
of  itself;  it  begins  to  throw  itself  into  the  objects  around,  and  to  live  in  the 
world  of  outward  realities."  We  may  recognize  a  similar  transition,  more  ra- 
pidly effected,  during  the  passage  from  sleep,  or  from  the  insensibility  of  a  swoon, 
to  the  state  of  complete  wakefulness ;  when  we  are  at  first  conscious  only  of 
our  own  sensations,  and  gradually  come  to  the  knowledge  of  our  condition  as  it 
relates  to  the  world  around,  and  of  the  position  and  circumstances,  new  and 
strange  as  they  may  be,  in  which  we  find  ourselves. 

790.  Now  the  elementary  notion  of  the  outness  or  externality*  of  the  cause  of 
sensational  change  is  undoubtedly  formed  by  a  law  of  our  mental  nature ;  and 
must  be  regarded  as  a  mental  instinct  or  intuition.  We  do  not  infer  the  exist- 
ence of  objective  realities  by  any  act  of  the  reason;  in  fact,  the  strict  application 
of  logical  processes  tends  rather  to  shake  than  to  confirm  the  belief  in  the  ex- 
ternal world;  but  the  qualities  of  matter  are  directly  and  immediately  recognized 
by  our  minds,  and  we  then  go  on  to  shape  the  information  we  have  thus  acquired, 
into  a  definite  notion  of  the  object.  Some  of  these  notions  are  so  simple,  and 
so  constantly  excited  by  certain  sensations,  that  we  can  scarcely  do  otherwise 
than  attribute  their  formation  to  original  and  fundamental  properties  of  the  mind, 
called  into  activity  by  the  sensations  in  question;  thus,  as  we  shall  hereafter 
see  (CHAP.  xv.  SECT.  5),  the  notion  of  the  projection  or  solidity  of  an  object  is 
necessarily  developed  in  our  minds,  when  two  pictures,  having  certain  relations 
of  dissimilarity,  are  projected  on  our  two  retinae.  But  in  other  cases,  the  ideas 
are  connected  with  the  sensations  by  habit  alone ;  and  it  is  entirely  due  to  the 
association  which  has  been  gradually  formed  between  them,  that  the  one  calls 
up  the  other.  Of  this  we  have  a  valuable  illustration  in  the  process  by  which 

1  "  Philosophy  of  Religion,"  p.  7. 

2  For  the  attachment  of  this  definite  meaning  of  the  term  Perception,  as  for  many  other 
services  to  Psychological  Science,  we  are  indebted  to  Sir  William  Hamilton. — See  especially 
his  note  on  the  "Philosophy  of  Sensation  and  Perception,"  in  his  edition  of  the  "Works 
of  Dr.  Reid." 

3  This  term  is  to  be  understood,  in  the  present  inquiry,  as  implying  what  is  external  to 
the  mind.     Viewed  in  that  aspect,  the  bodily  organism  stands  in  the  same  kind  of  relation 
to  it,  as  does  the  world  beyond ;  and  the  changes  in  the  former  which  give  rise  to  sensa- 
tions are  as  much  objective  as  are  those  of  the  latter. 


THE   CEREBRUM,   AND   ITS   FUNCTIONS.  759 

we  acquire  a  language.  A  certain  sound  conies  to  be  connected  in  the  mind  of 
the  child  with  a  certain  object,  its  knowledge  of  which  is  derived  through  the 
visual  or  other  sense ;  and  by  the  habitual  recurrence  of  this  connection,  the 
sensational  consciousness  of  the  sound  comes  to  suggest  the  idea  of  the  object, 
so  that  the  notion  of  bread  or  of  water  is  at  once  called  up  by  the  mention  of 
their  names ;  whilst,  on  the  other  hand,  the  idea  of  the  object  reproduces  that 
sensational  consciousness  of  the  sound  of  its  name,  which  is  the  necessary  guide 
in  the  pronunciation  of  the  word.  And  the  adult,  in  learning  a  new  language, 
goes  through  a  process  of  a  very  similar  kind;  the  association  being  first  formed 
between  its  words  and  the  words  of  the  language  already  familiar  to  him,  and 
the  former  at  last  directly  suggesting  the  corresponding  ideas,  without  any 
necessity  for  the  intermediate  process  of  translation.  On  the  other  hand,  the 
sight  or  the  sound  of  the  words  of  a  language  altogether  unknown  to  us,  excites 
no  other  respondent  idea  in  our  minds  ^than  that  which  arises  out  of  the  simple 
act  of  perception;  namely,  the  externality  of  the  object  which  has  impressed 
our  sense  of  vision  or  of  hearing.  But  the  case  is  different  with  regard  to  those 
signs  which  are  the  natural  expressions  of  ideas  ]  for,  in  so  far  as  they  are  so, 
they  intuitively  suggest  those  ideas  to  the  mind  of  another.  This,  however,  is 
much  more  noticeable  with  regard  to  the  signs  of  emotional  states — which  are 
very  early  interpreted  by  children,  and  also  by  the  lower  animals — than  with 
respect  to  those  which  express  simple  ideas.1 

791.  We  have  seen  that,  for  the  production  of  a  Sensation,  a  conscious  state 
of  mind  is  all  that  is  required ;  whilst,  on  the  other  hand,  for  the  exercise  of 
the  Perceptive  power,  a  certain  degree  of  attention  is  requisite ;  or,  in  other 
words,  the  Mind  must  be  directed  towards  the  Sensation.  And  thus  it  happens 
that,  owing  either  to  the  inactivity  of  the  Cerebrum,  or  to  the  complete  engross- 
ment of  the  mind  by  some  other  subject  of  thought,  the  sensation  may  neither 
be  perceived  nor  remembered,  notwithstanding  that  we  have  evidence,  derived 
from  the  respondent  movements  of  the  body,  that  it  has  been  felt.  Thus  a 
person  in  a  state  of  imperfect  sleep  may  start  at  a  loud  sound,  or  may  turn 
away  from  a  light  shining  on  his  face  ]  being  conscious  of  the  sensation,  and 
acting  automatically  upon  it,  but  having  no  consciousness  whatever  of  the  object 
which  gave  rise  to  it.  And,  in  like  manner,  a  person  in  a  state  of  profound 
abstraction  may  perform  many  automatic  movements  (§  749),  which  cannot  (so 
far  as  we  know)  be  excited  except  through  the  medium  of  sensation ;  and  yet 
the  exciting  sensations  are  neither  perceived  by  him  at  the  time,  nor  are  they 
afterwards  remembered ;  so  that,  when  he  is  aroused  from  his  reverie,  he  may 
be  astonished  to  find  himself  in  circumstances  altogether  different  from  those 
under  which  he  passed  into  it.  Sometimes,  however,  the  sensorial  impression 
may  excite  a  sort  of  imperfect  perception,  which  is  subsequently  remembered 
and  completed.  For  example,  the  student  who  does  not  hear  the  repeated 
strokes  of  the  clock  when  his  mind  is  entirely  given  up  to  his  object  of  pursuit, 
may  have  a  sort  of  vague  consciousness  of  them  if  his  attention  be  less  completely 
engrossed  by  his  studies ;  and  although  the  sounds  may  not  suggest  at  the 
moment  any  distinct  idea  of  the  passage  of  time,  yet,  when  he  subsequently 

1  The  deaf  and  dumb  are  trained  to  communicate  with  each  other,  not  merely  by  the 
"finger-language,"  by  which  words  are  alphabetically  spelled,  but  also  by  the  "sign-lan- 
guage," by  which  ideas  are  conveyed  through  the  much  more  direct  medium  of  single 
signs.  These  signs,  though  partly  conventional,  are  made  to  conform  as  nearly  as  possible 
to  the  natural  expressions  of  ideas ;  and  are  usually  acquired  very  quickly  by  the  deaf  and 
dumb,  whose  want  of  other  modes  of  utterance  forces  into  activity  a  mode  of  expressing 
their  ideas  and  emotions,  which  is  unnecessary  to  those  who  have  the  command  of  language, 
and  is  consequently  but  little  exerted  by  them.  Young  children,  however,  who  associate 
much  with  the  deaf  and  dumb,  very  readily  acquire  this  "  sign-language,"  and  will  often 
prefer  the  continued  use  of  it  to  the  acquirement  of  spoken  language. 


760  OF  THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

gives  his  attention  to  the  sensorial  impression,  he  may  remember  to  have  heard 
the  clock  strike,  and  may  even  be  able  to  retrace  the  number  of  strokes.1  When 
the  attention  is  directed,  however,  to  the  sonorous  impressions  (as  when  we  are 
listening  for  the  striking  of  the  clock),  or  when  it  is  not  so  closely  fixed  on  any 
other  object  as  that  it  may  be  attracted  by  the  sensations,  the  sounds  are  not 
only  recognized  as  proceeding  from  an  external  source,  which  is  a  simple  act  of 
Perception,  but,  by  a  mental  act  which  depends  upon  previous  associations,  the 
sounds  give  rise  to  the  complex  idea  of  the  striking  of  a  clock,  and  are  referred, 
it  may  be,  to  some  particular  clock.  Hence,  when  we  say  (as  we  commorly  do) 
that  we  have  heard  the  clock  strike,  we  affirm  that  which  is  not  strictly  correct ; 
for  that  which  we  hear  is  simply  the  series  of  sounds,  and  it  is  by  an  intuitive 
perception  that  we  are  led  to  consider  those  sounds  as  originating  in  an  external 
object;  whilst  the  formation  of  a  definite  notion  with  regard  to  the  nature  of 
that  object  is  an  act  of  judgment  and  comparison,  guided  by  past  experience. 
When  such  an  operation  has  been  very  frequently  performed,  however,  the  notion 
comes  to  be  so  directly  excited  by  the  sensation,  that  it  is  uniformly  and  neces- 
sarily called  up  when  the  attention  is  directed  to  the  latter;  the  individual 
being  quite  forgetful  of  the  mental  process  by  which  this  connection  was  origin- 
ally established. 

792.  Thus  the  formation  of  what  have  been  designated  as  acquired  perceptions, 
in  contradistinction  to  those  of  the  intuitive  kind,  bears  a  striking  analogy  to  the 
process  by  which  habitual  movements  come  to  be  linked  on  to  the  sensations 
that  prompt  them,  so  as  at  last  to  be  automatically  performed  although  originally 
guided  by  the  Will  (§  749).  And  it  can  scarcely  be  regarded  as  improbable, 
that,  in  the  one  case  as  in  the  other,  the  nervous  mechanism  grows  to  particular 
modes  of  activity  (§  726) ;  so  that  successions  of  action  are  uniformly  excited 
by  particular  stimuli,  which  were  not  provided  for  in  its  original  construc- 
tion. Such  a  view  harmonizes  well  with  the  fact  that  such  associations,  both 
between  sensations  and  respondent  movements,  and  between  sensations  and 
respondent  ideas,  are  formed  much  more  readily  during  the  period  of  childhood 
and  adolescence,  than  they  are  after  the  full  measure  of  development  has  been 
attained;  and  that  they  are  much  more  durable  in  the  former  case  than  in  the 
latter.  For  that  which  has  been  already  pointed  out  with  regard  to  the  nutri- 
tion of  other  tissues  (§  591),  may  not  unreasonably  be  applied  to  that  of  the 
Nervous  system;  that,  when  once  a  certain  mode  of  nutrition  has  been  fully 
established,  it  tends  to  perpetuate  itself,  provided  that  it  be  not  altogether 
unconformable  to  the  original  type.  Throughout  the  whole  constitution  of  Man, 
physical  and  mental,  we  witness  this  capacity  of  adaptation  to  a  great  variety 
of  circumstances;  and  it  seems  to  be  purposely  left  to  Man  to  educate  himself 
in  accordance  with  those  circumstances;  so  that  he  gradually  acquires  those 
modes  of  action  which  in  other  animals  are  directly  prompted  by  instinctive  or 
intuitive  tendencies.  The  idea  of  the  distance  of  an  object,  for  example,  is  one 
derived  in  Man  from  many  sources,  and  is  the  result  of  a  long  experience;  the 
infant,  or  the  adult  seeing  for  the  first  time,  has  to  bring  the  senses  of  sight  and 
of  touch  to  bear  upon  one  another,  in  order  to  obtain  it;  but,  when  once  the 
power  of  determining  it  is  acquired,  the  steps  of  the  process  are  lost  sight  of. 
In  the  lower  tribes  of  animals,  however,  in  which  the  young  receive  no  assist- 
ance from  their  parents,  there  is  an  evident  necessity  for  some  immediate  power 

1  It  is  curious  that  in  so  retracing  a  number,  we  are  often  assisted  by  mentally  repro- 
ducing the  succession  of  strokes,  imagining  their  recurrence,  until  we  feel  that  we  have 
counted  up  to  the  impression  that  was  left  upon  our  sensorium.  In  the  same  way,  if  asked 
how  many  stairs  there  are  in  a  staircase  which  we  are  in  the  habit  of  using,  we  may  not 
be  able  to  name  the  number ;  yet,  when  actually  ascending  or  descending,  we  are  conscious 
that  we  have  arrived  at  the  top  or  the  bottom,  by  the  completion  of  that  series  of  sensorial 
changes  which  has  become  habitual  to  us. 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  761 

of  forming  this  determination ;  since  they  would  not  be  able  to  obtain  their  food 
without  it.  Accordingly,  they  manifest  in  their  actions  a  perception  or  govern- 
ing idea  of  distances,  which  can  only  be  gained  by  Man  after  long  experience. 
A  fly-catcher,  for  instance,,  just  come  out  of  its  shell,  has  been  seen  to  peck  at 
an  insect,  with  an  aim  as  perfect  as  if  it  had  been  all  its  life  engaged  in  learn- 
ing the  art. — In  some  cases,  animals  seem  to  learn  that,  by  intuitive  perception, 
at  which  Man  could  only  arrive  by  the  most  refined  processes  of  reasoning,  or  by 
the  careful  application  of  the  most  varied  experience.  Thus,  a  little  fish,  named 
the  Chsetodon  rostratus,  is  in  the  habit  of  ejecting  from  its  prolonged  snout,  drops 
of  fluid,  which  strike  insects  that  happen  to  be  near  the  surface  of  the  water, 
and  cause  them  to  fall  into  it,  so  as  to  come  within  its  own  reach.  Now  by  the 
laws  of  refraction  of  light,  the  place  of  the  Insect  in  the  air  will  not  really  be 
that  at  which  it  appears  to  the  Fish  in  the  water ;  but  it  will  be  a  little  below 
its  apparent  place,  and  to  this  point  the  aim  must  be  directed.  But  the  differ- 
ence between  the  real  and  the  apparent  place  will  not  be  constant;  for  the  more 
perpendicularly  the  rays  enter  the  water,  the  less  will  be  the  variation;  and,  on 
the  other  hand,  the  more  oblique  the  direction,  the  greater  will  be  the  difference. 
Now  it  is  impossible  to  imagine  but  that,  by  an  intuitive  perception,  the  real 
place  of  the  Insect  :is  known  to  the  Fish  in  every  instance,  as  perfectly  as  it 
could  be  to  the  most  sagacious  Human  mathematician  who  might  determine  it 
in  each  case  by  a  process  of  calculation,  or  to  a  clever  marksman  who  had 
learned  it  practically  by  a  long  experience. 

793.  Just  as  the  simple  feelings  of  pleasure  or  pain  are  associated  with  par- 
ticular sensations  (§  759),  the  same  feelings  connect  themselves  with  particular 
Ideas;  and  thus  are  produced  those  Emotional  states  of  mind,  which,  directly 
or  indirectly,  determine  a  great  part  of  our  habits  of  thought,  and  are  largely 
concerned  in  the  government  of  our  conduct.  The  formation  of  a  true  desire, 
even  for  the  gratification  of  some  bodily  appetite,  requires  that  an  idea  of  the 
object  of  desire  shall  have  been  formed;  and  it  is  the  expectation  of  the  pleasure 
which  will  arise  from  the  performance  of  the  act  in  question,  or  of  the  pain 
which  will  be  produced  by  abstinence  from  it,  which  makes  the  idea  a  motive  to 
action.  A  careful  analysis  of  the  various  Propensities,  Moral  Feelings,  Senti- 
ments, &c.,  which  are  ranked  by  Metaphysicians  under  the  general  term 
"  active  principles/'  will  show  (the  Author  believes)  that  such  is  the  essential 
nature  of  all.  Thus,  Benevolence  is  the  pleasure  in  the  happiness  of  others; 
and  shows  itself  alike  in  the  habitual  entertainment  of  the  abstract  or  general 
idea,  and  in  the  direction  of  the  conduct  in  any  particular  instance.  So  there 
is  a  positive  pleasure,  in  some  ill-constituted  minds,  in  the  contemplation  of  the 
wihappiness  of  others ;  and  this  we  designate  as  Malevolence.  Again  the  Coin- 
bativeness  of  Phrenologists  is  nothing  else  than  the  pleasurable  idea  of  setting 
one's  self  in  antagonism  with  others ;  which  may  manifest  itself  either  physically 
or  psychically,  according  to  the  temperament  of  the  individual.1  So  Pride  (or 
self-esteem)  consists  in  the  pleasurable  contemplation  of  our  own  superior  excel- 
lencies; whilst  the  essence  of  Vanity  (or  love  of  approbation)  lies  in  the  plea- 
surable idea  of  the  applause  of  others.  Again,  in  Conscientiousness  we  have  the 

1  There  are  individuals  who  never  manifest  the  least  degree  of  physical  combativeness, 
who  yet  show  a  remarkable  love  of  opposition  in  all  their  psychical  relations  with  others. 
That  objections  will  be  raised  by  such  persons  to  any  plan  that  may  be  proposed,  we  can 
always  feel  sure,  though  we  may  not  have  the  remotest  idea  as  to  what  the  objection  may 
be  in  each  particular  case.  Persons  in  whom  this  tendency  exists  in  a  less  prominent 
degree  are  apt  to  see  objections  and  difficulties  first,  although  their  good  sense  may  subse- 
quently lead  them  to  consider  these  as  of  less  account,  or  to  be  outweighed  by  the  advan- 
tages of  the  scheme.  Such  was  the  case  with  the  late  Sir  Robert  Peel.  On  the  other 
hand,  those  who  are  spoken  of  as  of  sanguine  temperament  are  apt  to  lose  sight  of  the 
intervening  difficulties,  in  the  pleasurable  idea  of  the  result. 


T62  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

love  of  right,  that  is,  the  association  of  pleasure  with  the  idea  of  right;  Venera- 
tion may  be  defined  as  the  pleasurable  contemplation  of  rank  or  perfections 
superior  to  our  own;  and  the  source  of  Ambition,  which  is  in  some  degree  the 
antagonistic  tendency,  lies  in  the  pleasurable  idea  of  self-exaltation.  In  like 
manner,  Hope  is  the  pleasurable  contemplation  of  future  enjoyment;  Fear  is 
the  painful  contemplation  of  future  evil ;  and  Cautiousness  is  the  combination  of 
the  desire  to  avoid  anticipated  pain  with  the  pleasurable  contemplation  (an 
extremely  strong  feeling  in  many  individuals)  of  precautions  adapted  to  ward 
it  off. — The  same  view  may  be  applied  to  the  love  of  Truth,  of  Beauty,  of  Sub- 
limity, of  Goodness,  of  Order,  of  Possessions,  of  Country,  &c. ;  and  also  to  Cheer- 
fulness, Wit,  Humor,  &c.,  and  to  many  conditions  usually  considered  as  purely 
Intellectual.  And  in  fact,  the  association  of  sensor  ial  pleasure  with  any  idea, 
or  class  of  ideas,  gives  to  it  an  Emotional  character;  so  that  the  Emotional  states 
are  not  by  any  means  limited  within  the  categories  which  most  Psychologists 
have  attempted  to  lay  down;  these  being,  for  the  most  part,  generic  terms, 
which  comprehend  certain  groups  of  ideas  bearing  more  or  less  similarity  to  each 
other,  but  not  by  any  means  including  all  possible  combinations.1 — By  those 
who  regard  the  Propensities,  Moral  Feelings,  &c.,  as  simple  states  of  mind,  it 
is  usually  said  that  their  indulgence  or  exercise  is  attended  with  pleasure,  and 
the  restraint  of  them  with  pain.  But,  if  the  view  here  taken  be  correct,  it  is  the 
very  coexistence  of  pleasurable  or  painful  feelings  with  the  idea  of  a  given 
object,  that  causes  desire  or  aversion  as  regards  that  object ;  since  the  mind 
instinctively  pursues  what  is  pleasurable,  and  avoids  what  is  painful.  And  thus, 
according  to  the  readiness  with  which  these  different  classes  of  ideas  are  excited 
in  different  minds  (partly  depending  upon  original  constitution,  and  partly  upon 
the  habitual  direction  of  the  thoughts),  and  to  the  respective  degrees  in  which 
they  respectively  call  forth  the  sensorial  feelings  of  pleasure  or  pain  (as  to  which 
there  is  obviously  an  inherent  difference  amongst  individuals,  analogous  to  that 
which  exists  with  regard  to  the  feelings  of  pleasure  or  pain  excited  by  external 
sensations,  sights,  sounds,  tastes,  odors,  or  contacts),  will  be  the  disposition  of 
the  mind  to  entertain  them,  the  frequency  with  which  they  will  be  brought 
before  the  mental  view,  and  the  influence  which  they  will  exert  in  the  determi- 
nation of  our  conduct.2 

'  The  truth  of  this  statement  must  be  apparent  to  all  who  are  familiar  with  the  mani- 
festations of  Eccentricity  and  Insanity ;  for  we  frequently  see  pleasurable  feelings  associat- 
ing themselves  with  ideas,  which  to  ordinary  minds  appear  indifferent  or  are  even  regarded 
with  pain ;  and  thus  are  engendered  motives,  which  exert  a  most  powerful  influence  over 
the  conduct,  and  which,  if  not  kept  in  restraint  by  the  Will,  render  the  whole  being  their 
slave. — It  may  be  also  remarked,  in  this  place,  that  the  impossibility  of  classing  all  the 
Emotional  states  of  mind  under  a  limited  number  of  categories,  constitutes  a  most  serious 
and  fundamental  objection  to  any  system  which  professes  to  mark  out  in  the  Cerebrum 
distinct  seats  for  the  Animal  Propensities,  Moral  Feelings,  &c. 

2  The  above  view  of  the  nature  of  Emotional  states  was  first  developed  by  the  Author 
in  an  article  on  the  "Physiology  of  the  Brain,  "  in  the  "British  and  Foreign  Medical  Re- 
view," October,  1846. — It  was  not  until  he  had  thought  out  the  subject  for  himself,  on  the 
physiological  basis  which  is  here  given  to  it,  that  his  attention  was  directed  to  Mr.  James 
Mill's  masterly  "Analysis  of  the  Human  Mind,"  as  containing  a  very  similar  doctrine.  It 
has  been  a  great  satisfaction  to  him  to  find  that  a  Metaphysician  of  so  high  a  rank  had 
anticipated  his  conclusions,  and  this  upon  psychological  grounds  only ;  since  it  gives  him 
the  more  confidence  in  the  truth  of  the  physiological  doctrines  with  which  he  has  con- 
nected them.  His  principal  point  of  difference  from  Mr.  Mill  lies  in  the  greater  difference 
which  he  believes  to  exist  between  ideas  and  sensations ;  for  he  cannot,  with  Mr.  Mill,  re- 
gard an  Idea  as  a  mere  "  trace  or  copy  of  the  sensation,  which  remains  after  the  sensation 
ceases,"  but  must  consider  it  as  a  state  of  mind  altogether  different,  excited  or  induced 
by  sensations ;  and  consequently,  he  does  not  consider  the  emotional  state  to  consist  in 
the  anticipation  of  a  future  pleasurable  sensation,  since  the  pleasure  is  generally  associated 
with  ideational  states  which  have  no  analogy  whatever  to  the  sensations  which  excited 
them.  Thus  the  Love  of  Praise  does  not  consist  in  the  association  of  pleasure  with  the 


THE   CEREBRUM,   AND   ITS   FUNCTIONS.  763 

794.  The  influence  of  Emotional  conditions,  when  strongly  excited,  in  directly 
producing  involuntary  movements,  is  readily  explained  on  the  idea  that  the  Sen- 
sory Ganglia  are  the  seat  of  all  consciousness,  and  the  Cranio- Spinal  axis  the 
real  source  of  all  movement.  For  there  is  no  more  difficulty  in  understanding 
that  the  excitement  of  peculiar  states  of  consciousness  in  the  Sensorial  centres, 
through  the  instrumentality  of  the  Cerebrum,  should  give  rise  to  automatic 
movements,  than  that  such  movements  should  follow  similar  states  of  conscious- 
ness when  excited  by  impressions  made  upon  the  organs  of  vision,  hearing,  &c. 
And  the  correspondence  is  seen  to  be  very  close,  when  the  idea  (as  is  doubtless 
the  case  in  some  instances)  is  very  nearly  akin  to  the  sensation.  Thus,  the 
laughter  excited  by  the  act  of  tickling  is  a  purely  consensual  movement  (§  748) ; 
but,  in  a  very  "  ticklish"  person,  the  mere  idea  of  tickling,  suggested  by  point- 
ing a  finger  at  him,  is  sufficient  to  provoke  it.  So,  again,  laughter  may  be  ex- 
cited by  odd  sights  or  sounds  which  do  not  in  themselves  excite  any  emotional 
state,  and  which  we  call  "  ludicrous'7  merely  because  they  do  excite  laughter ; 
and  the  vivid  recollection  of  these,  being  attended  with  a  state  of  the  sensorium 
corresponding  to  that  produced  by  the  sensation,  may  give  rise  to  the  same  in- 
voluntary cachinnation.  But  laughter  may  also  be  excited  by  ideas  that  are  much 
more  removed  from  actual  sensations,  as,  for  example,  by  those  unexpected  com- 
binations of  ideas  of  a  purely  intellectual  nature,  which  we  designate  as  "  witty/ 
and  here,  too,  we  may  recognize  the  very  same  modus  operandi.  For  the  mere 
sound  or  sight  of  the  words  excites  no  feeling  of  the  ludicrous ;  the  sensation 
must  develop  an  ideational  change ;  and  it  is  the  latter  alone,  which,  reacting 
downwards  upon  the  Sensorium,  and  there  becoming  associated  with  the  feeling 
of  pleasure,  gives  rise  to  the  impulse  to  laugh.  The  same  might  be  shown  to 
be  the  case  with  regard  to  the  act  of  Crying ;  which  may  be  either  purely  con- 
sensual, being  excited  by  painful  sensations ;  or  may  be  induced  by  the  vivid 
recollection  of  past  or  the  anticipation  of  future  sensations;  or  may  be  excited 
by  ideas  which  have  no  direct  relation  to  sensational  states.  Again,  the  move- 
ments which  take  place  under  the  violent  excitement  of  the  passions  of  Anger, 
Lust,  &c.,  are  of  the  same  involuntary  character ;  being  directly  prompted  by 
feelings  which  may  be  either  excited  by  external  sensations,  or  by  internal  ideas 
more  or  less  akin  to  them.  Thus  the  passionate  man  who  receives  a  blow  in- 
stinctively makes  another  blow  in  the  direction  from  which  it  seemed  to  him  to 
come,  without  any  thought  of  whether  the  blow  was  accidental  or  intentional  j 
and  the  idea  of  an  insult,  which  is  a  source  of  mental  disturbance,  may  excite 
the  very  same  movement,  although  no  bodily  suffering  had  been  experienced. 
In  states  of  excessive  sexual  excitement,  again,  the  desire,  which  arises  out  of 
the  idea  of  the  object  (§  772),  produces  involuntary  movements  corresponding 
to  those  which  are  ordinarily  linked  on  to  the  actual  sensations  alone.  There 
are  many  of  the  movements  of  Expression,  which  are  referable  in  like  manner 
to  states  of  consciousness,  whether  pleasurable  or  painful,  which  may  arise  either 
from  sensational  or  from  ideational  conditions.  Thus  the  cheerful  aspect  of 
some  individuals  is  due  to  a  sense  of  general  physical  well-being,  and  is  al- 
together discomposed  by  anything  which  disturbs  this ;  whilst,  on  the  contrary, 
it  proceeds  in  others  from  a  happy  frame  of  mind  (which  may  be  partly  the 
result  of  original  constitution,  and  partly  of  habitual  self-direction),  disposing 
them  to  take  the  cheerful  view  of  everything  that  affects  themselves  or  others, 
notwithstanding  (it  may  be)  great  bodily  discomfort.  And  the  reverse  aspect 

auditory  or  visual  sensations  produced  by  spoken  or  written  words;  but  in  the  association 
of  pleasure  with  the  ideas  which  these  words  call  forth  in  the  mind. — A  view  of  the  nature 
of  the  Emotional  states  which  approaches  more  nearly  to  his  own,  though  not  developed 
with  the  analytical  precision  of  Mr.  Mill's,  is  contained  in  the  Rev.  Sydney  Smith's 
"Lectures  on  Moral  Philosophy;"  which,  although  delivered  early  in  the  present  century, 
were  not  published  until  the  year  1850. 


764  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

of  Gloom  may  in  like  manner  proceed  alike  from  bodily  or  from  mental  uneasi- 
ness.— All  these  facts  point,  therefore,  to  the  singleness  of  the  centre  from  which 
the  Emotional  movements  immediately  proceed;  and  to  its  identity  with  the 
centre  of  the  Sensori-motor  actions. 

795.  That  the  Emotional  and  Volitional  movements,  however,  differ  as  to 
their  primal  sources,  is  obvious,  not  merely  from  the  fact  that  they  are  fre- 
quently in  antagonism  with  each  other — the  Will  endeavoring  to  restrain  the 
Emotional  impulse,  and  either  succeeding  in  doing  so,  or  being  vanquished  by 
the  superior  force  of  the  latter — but  also  from  the  curious  fact,  which  Patho- 
logical observation  has  brought  to  light,  that  muscles  which  will  still  act  in 
obedience  to  emotional  impulses  may  be  paralyzed  to  the  volitional,  and  vice 
versa.  Thus,  for  example,  the  arm  of  a  man  affected  with  hemiplegia,  which 
no  effort  of  his  will  could  move,  has  been  seen  to  be  violently  jerked  under  the 
influence  of  the  mental  agitation  consequent  upon  the  sight  of  a  friend.  And 
in  the  case  of  softening  of  the  Spinal  Cord  already  referred  to  (§  704,  note),  the 
choreic  movements,  which  were  brought  on  by  the  mere  approach  of  any  one  to 
the  patient's  bed,  and  still  more  strongly  by  putting  a  question  to  him,  were 
most  violent  in  the  lower  limbs,  over  which  he  had  not  the  least  voluntary 
power. — It  is  in  the  different  forms  of  paralysis  of  the  Facial  nerve,  however, 
which  is  the  one  most  peculiarly  subservient  to  the  movements  of  Expression, 
that  we  have  the  best  evidence  of  this  distinctness.  For  it  sometimes  happens 
that  the  muscles  supplied  by  this  nerve  are  paralyzed  so  far  as  regards  the 
Will,  and  yet  are  still  affected  by  Emotional  states  of  mind,  and  take  their 
usual  part  in  the  automatic  actions  of  Respiration,  &c.,  retaining  also  their  usual 
tension,  so  that  no  distortion  is  apparent  unless  Voluntary  movements  be  at- 
tempted :  thus,  to  select  an  action  which  may  be  performed  either  consensually, 
emotionally,  or  voluntarily,  a  patient  affected  with  this  form  of  paralysis  can- 
not close  the  eyelid  by  an  act  of  his  will,  although  he  winks  when  he  feels  the 
uneasy  sensation  that  excites  the  action,  and  shuts  the  lids  when  the  sudden  ap- 
proach of  an  object  to  the  eye  excites  the  fear  of  injury  to  that  organ.  On  the 
other  hand,  the  paralyzed  condition  may  exist  in  regard  to  the  automatic  and 
emotional  actions  only,  so  that  the  muscles  lose  their  tension,  the  mouth  is 
drawn  to  one  side,  the  movements  of  expression  are  not  performed,  and  there 
is  no  involuntary  winking  :  yet  the  Will  may  still  exert  its  accustomed  control, 
and  may  produce  that  closure  of  the  lids  which  does  not  take  place  in  respond- 
ence  to  any  other  impulse.1 — It  has  been  inferred  by  Dr.  M.  Hall,3  from  cases 
of  this  kind,  that  the  Emotional  actions  are  among  those  which  are  performed 
by  his  "  true  spinal"  system  of  nerves,  as  distinct  from  the  sensori-volitional, 
and  that  they  therefore  fall  under  the  general  category  of  excito-motor  actions. 
But  it  is  obvious  that  they  differ  from  these  in  their  dependence,  not  merely 
upon  sensations,  but  also  upon  higher  states  of  mind ;  and  there  is  no  proof 
whatever  that  the  same  nerve-fibres  do  not  serve  for  the  conduction  of  the  mo- 
tor impulses  proceeding  from  the  two  different  mental  sources,  Volition  and 
Emotion,  as  we  have  seen  that  they  probably  do  for  the  volitional  and  automatic 
impulses  (§  753).3 

1  See  the  detailed  accounts  of  such  cases  in  Sir  C.  Bell's  work  on  "The  Nervous  Sys- 
tem of  the  Human  Body;"  also   "Brit,  and  For.  Med.  Rev.,"  vol.  iv.  p.  500,  and  vol. 
xiii.  p.  553. 

2  "Memoirs  on  the  Nervous  System,"  1837,  pp.  94,  et  seq. 

3  In  former  editions  of  this  Treatise,  the  author  maintained,  upon  the  principles  advo- 
cated by  Dr.  M.  Hall,  that  there  must  be  distinct  centres  and  conducting  fibres  for  Voli- 
tional, Emotional,  and  Reflex  movements.     Having  since  arrived  at  what  he  believes  to  be 
a  much  simpler  explanation  of  the  phenomena,  and  one  more  in  accordance   with  the 
facts  of  the  case,  he  does  not  hesitate  to  make  known  the  change  in  his  convictions ;  and 
would  hope  that  he  may  induce  those  who  may  have  adopted  his  previous  opinions,  to  re- 
consider the  subject  under  the  aspect  in  which  he  has  now  placed  it. 


THE   CEREBRUM,    AND    ITS    FUNCTIONS.  765 

796.  The  Emotions  are  concerned  in  Man,  however,  in  many  actions,  which 
are  in  themselves  strictly  voluntary.     Unless  they  be  so  strongly  excited  as  to 
get  the  better  of  the  Will,  they  do  not  operate  downwards  upon  the  Automatic 
centres,  but  upwards  upon  the  Cerebral ;  supplying  the  motives  by  which  the 
course  of  thought  and  of  action  is  habitually  determined.     Thus,  of  two  indi- 
viduals, with  differently  constituted  minds,  one  shall  judge  of  everything  through 
the  medium  of  a  gloomy  morose  temper,  which,  like  a  darkened  glass,  repre- 
sents to  his  judgment  the  whole  world  in  league  to  injure  him  ;  and  his  deter- 
minations being  all  based  upon  this  erroneous  view,  its  indications  are  exhibited 
in  his  actions,  which  are  themselves,  nevertheless,  of  an  entirely  voluntary  cha- 
racter.    On  the  other  hand,  a  person  of  a  cheerful,  benevolent  disposition  looks 
at  the  world  around  as  through  a  Claude  Lorraine  glass,  seeing  everything  in  its 
brightest  and  sunniest  aspect  •  and,  with  intellectual  faculties  precisely  similar 
to  those  of  the  former  individual,  he  will  come  to  opposite  conclusions  ;  because 
the  materials  which  form  the  basis  of  his  judgment  are  submitted  to  it  in  a 
very  different  condition.     Various  forms  of  Moral  Insanity  exhibit  the  same 
contrast  in  a  yet  more  striking  light.     We  not  unfrequently  meet  with  indi- 
viduals, still  holding  their  place  in  society,  who  are  accustomed  to  act  so  much 
upon  impulse,  and  to  be  so  little  guided  by  reason,  as  to  be  scarcely  regarded 
as  sane  ;  and  a  very  little  exaggeration  of  such  a  tendency  causes  the  actions  to 
be  so  injurious  to  the  individual  himself,  or  to  those  around  him,  that  restraint 
is  required,  although  the  intellect  is  in  no  way  disordered,  nor  are  any  of  the 
feelings  perverted.     Not  unfrequently  we  may  observe  similar  inconsistencies, 
resulting  from  the  habitual  indulgence  of  one  particular  feeling,  or  a  morbid 
exaggeration  of  it.     The  mother  who,  through  weakness  of  will,  yields  to  her 
instinctive  fondness  for  her  offspring,  in  allowing  it  gratifications  which  she 
knows  to  be  injurious  to  it,  is  placing  herself  below  the  level  of  many  less 
gifted  beings.     The  habit  of  yielding  to  a  natural  infirmity  of  temper  often 
leads  into  paroxysms  of  ungovernable  rage,  which,  in  their  turn,  pass  into  a 
state  of  maniacal  excitement.     It  is  not  unfrequently  seen,  that  a  delusion  of 
the  intellect  (constituting  what  is  commonly  known  as  Monomania)  has  in  reality 
resulted  from  a  disordered  state  of  the  feelings,  which  have  represented  every 
occurrence  in  a  wrong  light  to  the  mind  of  the  individual.     All  such  condi- 
tions are  of  extreme  interest  when  compared  with  those  which  are  met  with 
amongst  idiots,  and  animals  enjoying  a  much  lower  degree  of  intelligence ;  for 
the  result  is  much  the  same,  in  whatever  way  the  balance  between  the  feelings 
and  the  judgment  (which  is  so  beautifully  adjusted  in  the  well-ordered  mind  of 
Man)  is  disturbed  ;  whether  by  a  diminution  of  the  Voluntary  control  or  by  an 
undue  exaltation  of  the  feelings  and  passions. 

797.  This  double  modus  operandi  of  the  Emotional  consciousness — down- 
wards through  the  nerve-trunks  upon  the  muscular  apparatus,  and  also  upon 
many  of  the  Organic  functions  (CHAP,  xvni.) — and  upwards  upon  those  Cere- 
bral actions  which  give  rise  to  the  higher  states  of  Mental  consciousness — affords 
a  satisfactory  explanation  of  a  fact  which  is  practically  familiar  to  most  observers 
of  Human  nature,  namely,  that  violent  excitement  of  the  feelings  most  speedily 
subsides,  when  these  unrestrainedly  expend  themselves  (so  to  speak)  in  their 
natural  expressions.     Thus  it  may  be  commonly  noticed  that  those  who  are 
termed  demonstrative  persons  are  less  firm  and  deep  in  their  attachments,  than 
those  who  manifest  their  feelings  less;   for,  without  any  real  insincerity  or 
intentional  fickleness,  the  strongly  excited  feelings  of  the  former  are  rapidly 
calmed  down  by  the  expenditure  of  the  impulse  to  action  which  they  have 
generated  •  whilst  in  the  latter  the  very  same  feelings  acting  internally  acquire 
a  permanent  place  in  the  psychical  nature,  and  habitually  operate  as  motives  to 
the  conduct.     So,  again,  persons  who  are  ll  quick-tempered/7  manifesting  great 
irascibility  upon  small  provocations,  real  or  supposed,  are  usually  soon  appeased, 


766  OF   THE   FUNCTIONS   OF  THE   NERVOUS    SYSTEM. 

and  soon  forget  the  affront;  whilst  those  who  make  little  or  no  display  of  anger, 
are  very  apt  to  brood  over  and  cherish  their  feelings  of  indignation,  and  may 
visit  them  upon  the  unfortunate  object  of  them  when  some  favorable  opportunity 
happens  to  occur,  long  after  he  had  supposed  that  the  occurrence  which  had 
given  rise  to  them  was  forgotten.  There  is  an  instinctive  restlessness,  or  tend- 
ency to  general  bodily  movement,  in  some  individuals,  when  they  are  suffering 
under  emotional  excitement ;  the  indulgence  of  which  appears  to  be  a  sort  of 
safety-valve  for  the  excess  of  nerve-force,  whilst  the  attempt  at  its  repression  is 
attended  with  an  increase  in  the  excitement.  Most  persons  are  conscious  of  the 
difficulty  of  sitting  still,  when  they  are  laboring  under  violent  agitation,  and  of 
the  relief  which  is  afforded  by  active  exercise ;  and  this  is  particularly  the  case 
when  the  movements  are  such  as  naturally  express  the  passion  that  is  excited. 
Thus  the  combative  propensities  of  the  Irish  peasant  commonly  evaporate  speedily 
with  the  free  play  of  the  shillelagh ;  many  irascible  persons  find  great  relief  in 
a  hearty  explosion  of  oaths,  others  by  a  violent  slamming  of  the  door,  and  others 
(whose  excitement  is  more  moderate,  but  less  transient)  in  a  prolonged  fit  of 
grumbling.1  So,  again,  if  a  ludicrous  idea  be  suggested  to  our  consciousness, 
occasioning  an  impulse  to  laugh,  a  hearty  cachinnation  generally  works  off  the 
excitement,  and  we  may  be  surprised  a  short  time  afterwards  that  such  an 
absurdity  should  have  provoked  our  risibility;  but,  if  we  restrain  the  explosion, 
the  idea  continues  to  "  haunt"  us,  and  is  continually  perturbing  our  trains  of 
thought  until  we  have  given  free  vent  to  the  expression  of  it.  It  is  well  known, 
again,  that  the  depressing  emotions  are  often  worked  off  by  a  fit  of  crying  and 
sobbing;  and  the  "  relief  of  tears"  seems  manifestly  due  to  the  expenditure  of 
the  peni-up  nerve-force,  in  the  production  of  an  increased  secretion.  It  is 
noticed  in  this  case,  too,  that  the  absence  of  any  such  external  manifestations  of 
the  depressing  emotions  gives  them  a  much  greater  influence  upon  the  course 
of  thought,  and  upon  the  bodily  state  of  the  individual.  Those  who  really 
"  die  of  grief"  are  not  those  who  are  loud  and  vehement  in  their  lamentations, 
for  their  sorrow  is  commonly  transient,  however  vehement  and  sincere  while  it 
lasts;  but  they  are  those  who  have  either  designedly  repressed  any  such 
manifestations,  or  who  have  experienced  no  tendency  to  their  display;  and  their 
deep-seated  sorrow  seems  to  exert  the  same  kind  of  anti-vital  influence  upon  the 
organic  functions  that  is  exercised  more  violently  by  "  shock;"  producing  their 
entire  cessation  without  any  structural  lesion.3 

1  This  view  is  most  fully  confirmed  by  certain  phenomena  of  Insanity.     It  is  a  doctrine 
now  generally  received  among  practical  men,  that  paroxysms  of  violent  emotional  excite- 
ment are  much  more  likely  to  subside,  when  they  are  allowed  to  "work  themselves  off" 
freely,  without  any  attempt  at  mechanical  restraint ;  and  maniacal  patients  are  now  placed, 
in  all  well-managed  Asylums,  in  padded  rooms,  in  which  their  movements  can  do  no  injury 
to  themselves  or  others. — The  following  case  was  related  to   the  Author  by  his  friend  Dr. 
Howe,  of  Boston,  N.  E.,  the  instructor  of  Laura  Bridgrnan.     A  half-idiotic  youth  in  the 
Lunatic  Asylum  of  that  place  was  the  subject  (like  many  in  his  condition)  of  frequent  and 
violent  paroxysms  of  anger ;  and  with  the  view  of  moderating  these,  it  was  suggested  that 
he  should  be  kept  for  some  time  every  day  in  rather  fatiguing  exercise.     Accordingly  he 
was  employed  for  two  or  three  hours  daily  in  sawing  wood,  to  which  task  he  made  no  ob- 
jection; and  the  paroxysms  of  rage  never  displayed  themselves  except  on  Sundays,  when 
his  employment  was  intermitted.     It  having  been  considered,  however,  that  it  was  better 
for  him  to  spend  part  of  that  day  in  sawing  wood  than  to  be  irascible  during  the  whole  of 
it,  his  occupation  was  continued  through  the  whole  week,  when  he  became  completely 
tamed  down,  and  never  gave  any  more  trouble  by  his  passionate  displays. — This  case  ap- 
pears to  the  author  a  most  valuable  confirmation  of  the  doctrine  laid  down  in  the  text  ; 
which  is  one  whose  practical  bearings  are  most  important. 

2  The  Author  once  heard  the  following  singular  case  of  this  kind. — One  of  two  sisters, 
orphans,  who  were  strongly  attached  to  each  other,  became  the  subject  of  consumption; 
she  was  most  tenderly  nursed  by  her  sister  during  a  long  illness ;  but  on  her  death  the 
other,  instead  of  giving  way  to  grief,  in  the  manner  that  might  have  been  anticipated, 
appeared  perfectly  unmoved,  and  acted  almost  as  if  nothing  had  happened.     About  a 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  767 

798.  Like  the  other  sources  of  motor  activity  which  have  been  already 
treated  of,  the  Emotional  tendencies  may  become  morbidly  excited,  so  as  to 
produce  a  variety  of  movements  which  the  Will  vainly  attempts  to  control.  Of 
this  abnormal  condition  there  are  several  varieties.  The  most  common  is  the 
Hysterical  state  (most  frequent  among  females,  though  not  peculiar  to  them) 
in  which  smiles  and  cries,  laughter  and  sobbing,  are  strangely  intermingled,  and 
are  brought  on  by  the  slightest  emotional  excitement.  Now  here  the  deficiency 
lies  rather  in  the  power  of  voluntary  direction  of  the  thoughts,  than  in  the  power 
of  the  will  over  the  muscles;  for  such  patients  can  be  caused  to  restrain  them- 
selves, either  by  the  presentation  of  some  powerful  motive  (as  the  threat  of 
severe  discipline  in  the  event  of  the  return  of  the  paroxysm),  or  by  the  more 
gradual  exercise  of  the  power  of  the  Will  in  repressing  the  first  access  of  emo- 
tional excitement  by  the  withdrawal  of  the  mind  from  the  contemplation  of  all 
that  induces  it.  For  in  such  individuals  the  involuntary  movements  are  but 
the  expression  of  an  unhealthy  state  of  Mind;  in  which,  either  from  an  injudi- 
cious system  of  education,  or  from  habitual  want  of  self-control  on  the  part  of 
the  individual,  the  emotions  are  allowed  to  exercise  unchecked  domination;  and 
in  which  the  Will  is  at  last  so  weakened,  that  the  subject  of  the  disorder  can 
scarcely  be  considered  as  a  responsible  being. — There  are  other  Hysterical  cases, 
again,  in  which  there  is  less  of  mental  disorder,  but  a  greater  physical  excita- 
bility of  the  nervous  system ;  so  that  most  violent  paroxysms  of  a  tetanic  or 
epileptic  character  are  induced  by  very  slight  stimuli ;  and  any  emotional  excite- 
ment may  act  as  one  among  these  stimuli,  without,  however,  being  at  all  ex- 
cessive in  its  amount.  Here,  too,  the  Will  may  have  a  perfect  control  over  the 
muscles  at  all  other  times  than  when  they  are  thrown  into  violent  action  by  the 
reflex  excitability  of  the  Automatic  centres ;  and  the  treatment  of  such  cases 
must  be  in  great  degree  directed  to  the  removal  of  such  excitability,  which  fre- 
quently depends  upon  some  morbid  condition  of  the  uterus  or  ovaries.  At  the 
same  time,  there  is  no  doubt  that  an  habitually  perturbed  state  of  the  emotions, 
and  especially  of  those  relating  to  sexual  love,  has  a  most  decided  influence  both 
in  first  inducing  and  in  subsequently  maintaining  the  automatic  excitability ; 
and  that  whilst  mental  tranquillity  and  self-regulation  are  almost  essential  to 
recovery,  nothing  promotes  it  so  much  as  the  supervention  of  a  more  favorable 
state  of  feeling,  arising  out  of  the  prospective  realization  of  desires  repressed  or 
of  hopes  deferred. — But  there  are  other  states  in  which  Emotional  excitement 
has  a  morbid  power  of  inducing  muscular  movements;  and  this  not  through  any 
deficiency  of  due  control  over  the  feelings,  but  often  concurrently  with  a  want 
of  power  to  bring  the  Will  to  bear  upon  the  muscles.  This  condition  in  its  ex- 
treme form  is  known  as  Chorea,  the  nature  of  which  will  be  hereafter  examined 
more  minutely ;  at  present  it  will  be  sufficient  to  refer  to  some  of  those  slighter 
forms  of  it  which  have  received  no  definite  appellation.  Thus,  there  are  individu- 
als not  at  all  remarkable  for  their  emotional  excitability,  who  cannot  avoid  making 
the  most  extraordinary  grimaces  whenever  anything  happens  which  in  the  least 
disturbs  their  usual  equanimity,  notwithstanding  that  they  may  make  all  the 
efforts  in  their  power  to  prevent  these.1  The  general  muscular  agitation  of  the 

fortnight  after  her  sister's  death,  however,  she  was  found  dead  in  her  bed ;  yet  neither 
had  there  been  any  symptoms  during  life,  nor  was  there  any  post-mortem  appearance, 
which  in  the  least  degree  accounted  for  this  event,  of  which  no  explanation  seems  admis- 
sible, except  the  depressing  influence  of  her  pent-up  grief  upon  her  frame  generally, 
through  the  nervous  system. 

1  The  Author  has  a  case  at  present  under  his  observation,  in  which  not  merely  the  face, 
but  the  body  and  limbs,  are  thrown  into  the  most  extraordinary  contortions,  upon  any 
agitation  of  the  feelings,  however  trifling.  This  gentleman,  a  man  of  education  and  intel- 
ligence, of  extreme  benevolence  of  character,  and  a  mind  habitually  well-regulated,  can 
scarcely  walk  the  streets  without  being  liable  to  the  induction  of  paroxysms  of  this  kind, 
by  causes  that  could  scarcely  have  been  supposed  capable  of  thus  operating.  For  example, 


768  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

confirmed  Stammerer  is  another  case  in  point;  here  we  have  a  deficiency  in  the 
power  of  the  will  over  the  Muscles,  at  first  displayed  only  in  regard  to  those  of 
Voice;  but  when  feelings  of  discomfort  have  been  aroused  by  the  failure  of 
attempts  to  articulate,  this  want  of  voluntary  control  extends  itself  to  the  mus- 
cular system  in  general,  which  is  thrown  into  a  sort  of  paroxysmal  effort,  that 
usually  subsides  only  with  the  explosion  of  the  desiderated  sound. 

799.  The  influence  of  Emotional  excitement  may  operate  upon  the  muscles, 
however,  not  only  in  giving  rise  to  movements  which  can  be  attributed  to  no 
other  source,  but  also  in  affecting  the  power  of  the  Will  over  the  muscular 
system,  by  intensifying  or  weakening  its  action.  For  there  can  be  no  doubt 
that,  under  the  strong  influence  of  one  class  of  feelings,  the  Will  can  effect 
results  such  as  the  individual  would  scarcely  even  attempt  in  his  calmer  moments; 
whilst  the  influence  of  another  class  of  feelings  is  exercised  in  precisely  the  oppo- 
site direction,  weakening  or  even  paralyzing  the  force  which  was  previously  in 
full  activity.  But  the  same  emotion  does  not  always  act  in  the  same  mode  ; 
thus,  the  fear  of  danger  may  nerve  one  man  to  the  most  daring  and  vigorous  efforts 
to  avert  it,  whilst  another  is  rendered  powerless,  and  gives  way  to  unavailing 
lamentations;  and  the  ardent  anticipation  of  success  may  so  unsettle  the  deter- 
minative energy  of  one  aspirant,  as  to  prevent  him  from  attaining  his  object, 
whilst  another  may  only  be  sustained  by  it  in  the  toilsome  struggle  of  which  it 
is  the  final  reward.  Now  in  order  that  this  variety  may  be  explained,  and 
the  modus  operandi  of  the  Emotions  on  strictly  Volitional1  actions  may  be  duly 
comprehended,  we  must  here  state  two  of  the  essential  conditions  of  the  latter ; 
one  of  which  is,  that  there  should  be  not  merely  a  distinct  conception  of  the 
purpose  to  be  attained,  but  also  a  belief  that  the  purpose  will  or  at  least  may  be 
attained ;  whilst  the  other  is,  that  the  mental  energy  should  be  to  a  great  extent 
withdrawn  from  other  objects,  and  should  be  concentrated  upon  that  towards 
which  the  Will  is  directed. — It  is  within  the  experience  of  every  one,  that  there 
is  nothing  which  tends  so  much  to  the  success  of  a  volitional  effort,  as  a  confi- 
dent expectation  of  its  success;  whilst  nothing  is  so  likely  to  induce  failure  as 
the  apprehension  of  it.  Now,  in  so  far  as  regards  this  mode  of  their  operation 
alone,  the  tendency  of  the  cheerful  or  joyous  emotions  being  to  suggest  and  keep 
alive  the  favorable  anticipations,  whilst  that  of  the  depressing  emotions  (of 
almost  any  kind)  is  to  bring  before  the  view  all  the  chances  of  failure,  the 
former  will  increase  the  power  of  the  volitional  effort,  and  the  latter  will  dimm- 
ish it.  And  they  exert  also  a  direct  influence  on  the  physical  powers,  through 
the  organs  of  circulation  and  respiration;  the  heart's  impulses  being  more 
vigorous  and  regular,  and  the  aeration  of  the  blood  being  more  effectually 
performed,  in  the  former  condition  than  in  the  latter. — But  an  altogether 
contrary  effect  may  be  produced  by  the  operation  of  these  two  classes  of  emo- 
tions through  the  second  of  the  above  channels.  For  the  more  completely 
the  mental  energy  can  be  brought  into  one  focus,  and  all  distracting  objects 
excluded,  the  more  powerful  will  be  the  volitional  effort;  and  the  effect  of 

he  was  one  day  seized  by  one  of  these  attacks,  in  consequence  of  seeing  a  man  miss  his 
footing  (as  he  thought)  in  descending  from  the  top  of  an  omnibus ;  and  the  pleasurable  ex- 
citement of  meeting  a  friend  usually  induces  tht  same  result.  The  tendency  varies  very 
considerably  in  its  degree  according  to  the  general  condition  of  his  health. 

1  The  term  volitional  was  some  years  since  suggested  by  Dr.  Symonds,  in  an  excellent 
essay  on  the  "Connection  between  Mind  and  Muscle,"  published  in  the  "West  of  England 
Journal,"  1835,  as  expressing  more  emphatically  than  voluntary  the  characters  of  an  action 
proceeding  from  a  distinct  choice  of  the  object,  and  from  a  determinative  effort  to  attain 
it.  The  word  voluntary  may  perhaps  be  applied  to  that  wider  class  of  actions,  in  which 
there  is  no  very  distinct  choice  or  conscious  effort,  but  in  which  the  movement  flows  as  it 
were  spontaneously  from  the  antecedent  mental  state ;  the  consciousness,  however,  being 
fully  awake  to  its  performance,  and  the  will  being  brought  to  bear  determinately  upon  it, 
whenever  an  opposing  motive  tends  to  check  the  process  or  to  alter  its  direction. 


THE   CEREBRUM,    AND    ITS   FUNCTIONS.  769 

emotional  excitement  will  thus  in  great  degree  depend  upon  the  intellectual 
constitution  which  the  individual  may  happen  to  possess.  For  if  he  have  a 
considerable  power  of  abstraction  and  concentration,  and  a  full  conviction  that 
he  has  selected  the  best  or  the  only  means  to  accomplish  his  end,  the  intensest 
fear  of  the  consequences  of  failure  will  only  increase  the  force  of  the  motive 
which  prompts  the  effort;  and  the  whole  energy  of  which  his  nature  is  capable 
will  display  itself  in  the  attempt.  In  a  man  of  this  temperament,  the  most 
joyous  anticipation  of  success  will  produce  no  abatement  of  his  efforts,  no  dis- 
traction of  his  attention;  but  will  rather  tend  to  keep  him  steady  to  his  purpose 
until  it  shall  have  been  accomplished;  and  then  only  does  he  dare  to  abandon 
himself  to  the  current  of  ideas  which  rolls  in  upon  his  consciousness,  so  soon  as 
his  attention  is  free  to  entertain  them.  But  the  mind  which  is  deficient  in  the 
power  of  concentrativeness  is  lamentably  deranged  by  any  kind  of  emotional 
excitement  in  the  performance  of  any  voluntary  effort.  For  the  fear  of  failure 
is  constantly  suggesting  to  him  new  distresses,  weakens  his  confidence  in  any 
method  suggested  for  his  action,  and  makes  him  direct  his  attention,  not  to 
some  fixed  plan  as  the  best  or  the  only  feasible  one,  but  to  any  and  every  means 
that  may  present  a  chance  of  success,  or  may  even  serve  to  avert  his  thoughts 
from  the  dreaded  catastrophe;  whilst,  on  the  other  hand,  the  joyous  anticipation 
of  success  leads  him  to  allow  his  thoughts  to  direct  themselves  towards  all  its 
agreeable  consequences,  instead  of  fixing  his  intellectual  and  volitional  energy 
upon  the  means  by  which  success  is  to  be  attained. 

800.  If  this  be  the  true  solution  of  the  mode  in  which  the  Emotions  chiefly 
affect  the  exercise  of  our  Volitional  powers,  we  should  expect  that  similar  effects 
might  be  induced,  without  any  Emotional  excitement,  by  means  which  affect 
the  Intellectual  consciousness  alone ;  and  that  thus  an  action  otherwise  impos- 
sible to  the  individual  may  be  performed  by  him,  if  (1)  his  mind  be  possessed 
with  a  full  assurance  of  success,  and  (2)  his  entire  motor  energy  be  concentrated 
in  the  single  exertion ;  whilst,  on  the  other  hand,  an  action  which  can  be  or- 
dinarily performed  with  the  greatest  facility  may  become  absolutely  impossible 
to  him,  if  (1)  his  mind  be  entirely  possessed  with  the  idea  of  its  impossibility, 
or  even  (2)  if,  while  his  judgment  entertains  doubts  of  success,  his  attention  be 
distracted  by  a  variety  of  objects,  so  that  he  cannot  bring  it  to  bear  upon  the  one 
effort  which  may  alone  be  needed. — Now  experience  shows  that  such  is  really  the 
case;  but  as  this  experience  is  the  most  remarkable  in  regard  to  certain  states  of 
the  mind  in  which  these  two  modes  of  operation  may  be  worked  in  combination,  it 
will  be  sufficient  to  refer  to  them  for  the  demonstration  (§§  822,  825).     And 
having  now  sufficiently  considered  the  physiological  conditions  of  the   purely 
Emotional  actions — which,  in  regard  alike  to  the  state  of  consciousness  wherein 
they  originate,  and  to  the  share  which  the  Sensorial  centres  have  in  generating 
that  state,  may  be  considered  as  most  nearly  allied  to  the  Consensual — we  pass 
on  to  those  Psychical  operations,  of  which  the  Cerebrum  must  be  regarded  as 
the  exclusive  instrument. 

801.  Though  it  is  now  universally  admitted  among  Psychologists  that  the 
mind  does  not  come  into  existence  with  thoughts  ready  formed,  or  u  innate  ideas," 
yet  there  are  few  who  will  deny  that  we  are  born  with  such  tendencies  to  thought, 
that,  when  these  are  called  into  activity,  certain  results  are  sure  to  follow ;  and 
further,  that  whilst  there  is  a  certain  fundamental  similarity  in  these  tendencies 
to  thought,  among  all  minds  of  ordinary  constitution — so  that,  when  excited 
to  action  in  the  same  manner,  the  same  results  shall  be  evolved — yet  that  there 
is  such  a  diversity  in  the  relative  degree   of  these  tendencies  in  different  indi- 
viduals, as  of  itself  becomes  a  source  of  different  habits  of  thought.     But  the 
habits  of  thought  are  also  determined  in  great  degree  by  the  influence  of  the 
emotions ;  for,  whilst  we  are  disposed  to  give  ourselves  up  to  the  contemplation 
of  subjects  with  which  pleasurable  feelings  are  connected,  we  are  equally  prone 

49 


770  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

to  withdraw  our  attention  from  those  that  are  accompanied  with  feelings  of  pain 
or  discomfort  ;  and,  as  the  relative  intensity  of  the  different  Emotional  states 
varies  greatly  among  different  individuals,  it  becomes,  as  already  noticed  (§  796), 
a  source  of  extreme  diversity  in  the  formation  of  all  those  conclusions  by  which 
the  conduct  of  life  is  directed,  and  tends  to  establish  certain  uniformities  of  mental 
action  for  each  individual,  which  constitute  what  is  termed  his  "  character." 
But  further,  we  are  not  to  look  merely  at  congenital  peculiarities  of  psychical 
constitution,  as  the  source  of  original  habitudes  of  thought ;  for  as  the  external 
conditions  in  which  every  individual  is  placed,  differ  to  a  certain  extent  from 
those  which  affect  each  one  of  his  fellows,  so  does  it  happen  that,  as  the  deve- 
lopment of  every  kind  of  capacity  for  mental  action  is  augmented  (like  the  nu- 
trition of  muscle  and  nerve)  by  its  habitual  exercise,  the  strength  of  that  capacity, 
and  its  tendency  to  exert  an  active  influence  on  the  course  of  thought,  will  pa'rtly 
depend  upon  the  degree  in  which  circumstances  call  it  into  play,  especially  dur- 
ing the  period  when,  in  the  natural  progress  of  psychical  evolution,  it  is  first 
taking  a  prominent  share  in  the  operations  of  the  mind.  Hence  there  is  a  set  of 
acquired  habitudes  of  thought,  which,  no  less  than  those  dependent  upon  original 
constitution,  determine  the  consequences  of  any  particular  impression  upon  the 
"  ideational  consciousness;"  and  which  thus  form  part  of  the  "character"  of 
each  individual,  at  any  one  period  of  his  existence.  But  the  psychical  tenden- 
cies of  every  one  undergo  a  consecutive  change  in  the  progress  of  life.  Infancy, 
Childhood,  Youth,  Adolescence,  Adult  age,  the  period  of  Decline,  and  Senility, 
have  all  their  characteristic  phases  of  psychical  as  of  physical  development  and 
decline ;  and  this  is  shown,  not  merely  in  the  general  advance  of  the  intellectual 
powers  up  to  the  period  of  middle  life,  and  in  their  subsequent  decay,  but  in  a 
gradual  change  in  the  balance  of  the  springs  of  action  which  are  furnished  by 
the  emotional  states,  the  pleasures  and  pains  of  each  period  being  (to  a  certain 
extent)  of  a  different  order  from  those  of  every  other.  This  diversity  may  be 
partly  attributed  to  changes  in  the  physical  constitution;  thus,  the  sexual  feeling, 
which  has  a  most  powerful  influence  on  the  direction  of  the  thoughts  in  ado- 
lescence, adult  age,  and  middle  life,  has  comparatively  little  effect  at  the  earlier 
and  later  periods.  So  again,  the  thirst  for  novelty,  and  the  pleasure  in  mental 
activity,  which  so  remarkably  characterize  the  young,  when  contrasted  with  the 
obtuseness  to  new  impressions  and  the  pleasure  in  tranquil  occupations  which 
mark  the  decline  of  life,  may  perhaps  be  attributed,  in  part  at  least,  to  the  greater 
activity  of  the  changes,  both  of  disintegration  and  reparation,  of  which  the  nerv- 
ous system  (in  common  with  the  rest  of  the  organized  fabric)  is  the  subject 
during  the  earlier  part  of  life,  and  to  its  diminished  activity  as  years  advance. 
But  there  are  other  changes,  which  cannot  be  so  distinctly  traced  to  any  physical 
source,  but  which  yet  are  sufficiently  constant  in  their  occurrence,  to  justify 
their  being  regarded  as  a  part  of  the  developmental  history  of  the  psychical 
nature;  so  that  each  of  the  "  Seven  Ages  of  Man"  has  its  own  character,  which 
may  be  with  difficulty  defined  in  words,  but  which  is  recognized  by  the  appre- 
hension, as  it  forces  itself  upon  the  experience,  of  every  one. 

802.  It  is  universally  admitted  that,  notwithstanding  all  the  obvious  diver- 
sities of  Human  character  and  Mental  action,  there  are  certain  fundamental 
uniformities  which  may  be  traced  throughout  the  whole  of  this  series ;  and  it 
is  on  the  basis  afforded  by  these,  that  the  Science  of  Psychology  is  erected,  to 
which  may  be  applied,  with  a  mere  alteration  of  form,  the  definition  given  of 
Physiology  in  the  first  page  of  this  treatise :  "  The  object  of  the  science  of 
Psychology  is  to  bring  together,  in  a  systematic  form,  the  phenomena  which  nor- 
mally present  themselves  during  the  existence  of  thinking  minds ;  and  to 
classify  and  compare  these  in  such  a  manner  as  to  deduce  from  them  those  gene- 
ral Laws  or  Principles  which  express  the  conditions  of  their  occurrence,  and  to 
determine  the  causes  to  which  they  are  attributable."  As  our  present  object, 


THE   CEREBRUM,   AND   ITS   FUNCTIONS.  771 

however,  is  not  to  investigate  the  operations  of  the  Mind  itself,  but  only  to  con- 
sider their  relations  to  those  of  the  bodily  Organism,  we  shall  here  enter  into 
the  examination  of  the  nature  and  laws  of  psychical  phenomena,  only  so  far  as 
may  be  requisite  for  the  due  explanation  of  those  bodily  changes  which  are  re- 
lated to  them. — Of  the  nature  of  the  connection  between  Nervous  action  and 
Mental  action,  we  can  form  no  distinct  idea.  Few  Physiologists  would  be  dis- 
posed to  deny  that  the  Cerebrum  is  the  instrument  of  Psychical  powers ;  and 
yet  no  one  has  been  able  to  form  a  self-consistent  theory  of  the  mode  in  which 
it  is  so.  Some  who  have  attended  exclusively  to  the  close  relationship  which 
indubitably  exists  between  corporeal  and  mental  states  have  thought  that 
all  the  operations  of  the  Mind  are  but  expressions  or  manifestations  of  material 
changes  in  the  Brain ;  that  thus  Man  is  but  a  thinking  machine,  his  conduct 
being  entirely  determined  by  his  original  constitution,  modified  by  subsequent 
conditions  over  which  he  has  no  control,  and  his  fancied  power  of  self-direction 
being  altogether  a  delusion  ;  and  that  notions  of  "  duty"  or  lt  responsibility" 
have  no  real  foundation,  Man's  character  being  formed  for  him  and  not  by  him, 
and  his  mode  of  action  in  each  individual  case  being  simply  the  consequence  of 
the  reaction  of  his  Cerebrum  upon  the  circumstances  which  called  it  into  play.1 
On  this  view,  what  is  commonly  termed  Criminality  is  but  one  form  of  Insanity, 
and  ought  to  be  treated  as  such ;  Insanity  itself  is  nothing  else  than  a  disor- 
dered action  of  the  Brain  ;  and  the  highest  elevation  of  Man's  Psychical  nature 
is  to  be  attained  by  due  attention  to  all  the  conditions  which  favor  his  physical 
development.  But  again,  there  are  others  who  have  limited  themselves  to  the 
cognizance  of  Mental  phenomena,  and  who  maintain  the  very  opposite  doctrine 
in  regard  to  their  nature  and  source.  To  them  the  Mind  appears  in  the  light 
of  a  separate  immaterial  existence,  mysteriously  connected,  indeed,  with  a 
bodily  instrument,  but  not  dependent  upon  this  in  any  other  way  for  the  condi- 
tions of  its  operation,  than  as  deriving  its  knowledge  of  external  things  through 
its  agency,  and  as  making  use  of  it  to  execute  its  determinations,  so  far  as  these 
relate  to  material  objects.  On  this  hypothesis,  the  operations  of  the  Mind  it- 
self, having  no  relation  whatever  to  those  of  Matter,  are  never  themselves 
affected  by  conditions  of  the  corporeal  organism,  whose  irregularities  or  defects 
of  activity  only  pervert  or  obscure  the  outward  manifestations  of  the  Mind, 
just  as  the  light  of  the  brightest  lamp  may  be  dimmed  or  distorted  by  passing 
through  a  bad  medium ;  and,  further,  as  the  Mind  is  thus  independent  of  its 
material  tenement,  and  of  the  circumstances  in  which  this  may  chance  to  be 
placed,  but  is  endowed  with  a  complete  power  of  self-government,  it  is  respon- 
sible for  all  its  actions,  which  must  be  judged  of  by  certain  fixed  standards. 
Those  who  most  fully  and  legitimately  carry  out  this  doctrine  are  ready  to 
maintain  that  even  in  the  state  of  Intoxication,  there  is  no  truly  mental  per- 
version, and  that,  in  spite  of  appearances,  the  mind  of  the  Lunatic  (divinte 
particula  aurse)  is  perfectly  sound,  its  bodily  instrument  being  alone  disordered. 
803.  Now  the  first  of  these  doctrines,  legitimately  designated  the  Materialist, 
recognizes  certain  great  facts,  on  which  the  Physiologist  can  scarcely  entertain  a 

1  For  the  latest  and  most  thorough-going  expression  of  this  doctrine,  see  the  "Letters 
on  the  Laws  of  Man's  Nature  and  Deve  opment,"  by  Henry  G.  Atkinson  and  Harriet 
Martineau. — A  few  extracts  will  suffice  to  show  the  bearings  of  this  system  of  philosophy. 
"Instinct,  passion,  thought,  &c.  are  effects  of  organized  substances."  "All  causes  are 
material  causes."  "In  material  conditions,  I  find  the  origin  of  all  religions,  all  philoso- 
phies, all  opinions,  all  virtues,  and  '  spiritual  conditions  and  influences,'  in  the  same 
manner  that  I  find  the  origin  of  all  diseases  and  of  all  insanities  in  material  conditions 
and  causes."  "  I  am  what  I  am ;  a  creature  of  necessity  ;  I  claim  neither  merit  nor  de- 
merit." "  I  feel  that  I  am  as  completely  the  result  of  my  nature,  and  impelled  to  do  what 
I  do,  as  the  needle  to  point  to  the  north,  or  the  puppet  to  move  according  as  the  string  is 
pulled."  "  I  cannot  alter  my  will,  w  be  other  than  what  I  am,  and  cannot  deserve  either 
reward  or  punishment." 


772  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

doubt,  notwithstanding  the  denial  of  their  validity  by  those  who  have  had  com- 
paratively little  opportunity  of  observing  them  ;  we  refer  to  the  influence  of  the 
Body  upon  the  Mind,  of  physical  upon  psychical  states  ;  an  influence  which  no 
one  will  fail  to  recognize  who  studies  its  phenomena  with  freedom  from  precon- 
ceived theory.     But,  in  reducing  the  Thinking  Man  to  the  level  of  "  a  puppet 
that  moves  according  as  its  strings  are  pulled/'  it  is  so  utterly  antagonistic  to 
our  own  consciousness  of  possessing  a  self-determining  power — whilst,  in  put- 
ting aside,  as  mere  delusions,  what  we  feel  to  be  the  noblest  conceptions  of  our 
nature,  it  is  so  thoroughly  repugnant  to  the  almost  intuitive  convictions  which 
we  draw  from  the  simplest  application  of  our  Intelligence  to  our  own  Moral 
Sense — that  we  feel  its  essential  fallacies  with  a  certainty  that  renders  logical 
proof  quite,  irrelevant. — On  the  other  hand,  the  purely  Spiritualist  doctrine  is 
no  less  encumbered  with  difficulties,  nor  less  opposed  to  facts  of  most  familiar 
occurrence.     For  whilst  it  fully  recognizes  all  that  the  other  ignores,  it  ignores 
all  that  it  recognizes ;  and  in  placing  the  Mind  outside  of  the  Body  (so  to 
speak),  and  in  denying  that  the  action  of  the  Mind  is  ever  disordered  by  cor- 
poreal conditions,  it  places  us  in  the  dilemma  of  either  rejecting  the  plainest 
evidence,  or  of  admitting  that,  after  all,  we  know  nothing  whatever  about  the 
Mind  itself,  all  that  we  do  know  being  that  lower  part  of  our  mental  nature 
which  operates  on  the  body  and  is  in  its  turn  affected  through  it.     For  it  must 
be  admitted  that,  in  the  delirious  ravings  of  Intoxication  or  of  Fever,  or  in  the 
perverted  reasoning  of  the  Lunatic,  we  have  the  same  evidence  of  mental  ope- 
ration that  we  have  in  the  sayings  and  doings  of  the  same  individuals  in  a 
state  of  sanity ;  and  ample  testimony  to  this  effect  is  borne  by  those  who  have 
observed  their  own  mental  state  during  the  access  of  these  conditions,  and  who 
have  described  the  alteration  which  takes  place  in  the  course  of  their  thoughts, 
when  as  yet  neither  the  sensorial  nor  the  motor  apparatus  was  in  the  least  per- 
turbed.1    Nothing  can  be  more  plain  to  the  unprejudiced  observer,  than  that 
the  introduction  of  Alcohol,  or  Opium,  or  other  intoxicating  agents,  into  the 
circulating  system,  perverts  the  action  of  the  mind,  disordering  the  usual  se- 
quence of  phenomena  most  purely  psychical,  and  occasioning  new  and  strange 
results,  which  are  altogether  diverse  from  those  of  its  normal  operation.     And 
when  once  this  influence  of  physical  conditions  upon  mental  phenomena  has 
been  admitted,  we  can  scarcely  refrain  from  attributing  to  it  a  very  wide  range 
of  action ;  seeing  as  we  do  how  very  much  the  due  balance  of  the  Emotions  is 
dependent  upon  the  purity  of  the  blood  and  the  general  vigor  of  the  system, 
and  how  strangely  the  normal  succession  of  Intellectual  operations  may  be  in- 
terrupted or  altered  by  local  affections  of  the  Cerebrum.     No  Physiologist  could 
venture  to  deny,  in  the  face  of  the  crowd  of  facts  which  force  themselves  on 
his  attention,  that  all  Mental  phenomena  are  inextricably  linked  with  Vital 
changes  in  the  Nervous  system  ;  and  that  the  regular  performance  of  the  latter 
(which  we  have  seen  to  be  dependent  on  the  due  combination  of  physical  and 
dynamical  conditions)  is  essential  to  the  normal  sequence  of  the  former.     Nor 
can  any  one  who  duly  examines  the  evidence  which  has  been  collected  on  the 
subject  of  Idiocy  and  Cretinism,  feel  any  doubt  that,  in  the  original  develop- 
ment of  the   Mental  powers,  the  healthful  activity  of  the  Corporeal  organism 
has  just  as  important  a  share,  as  it  has  in  their  subsequent  maintenance. 

804.  It  may  be  fairly  asked,  then,  whether  there  be  any  mode  of  combining 
the  truths  contained  in  the  Materialist  and  Spiritualist  doctrines,  and  of  separat- 
ing them  from  their  associated  errors ;  and  whether  any  general  expression  can 
be  framed,  which  may  be  in  harmony  alike  with  the  result  of  scientific  inquiry 

1  See  especially  the  work  of  M.  Moreau  "Du  Hacbisch  et  de  I'AlSe'nation  Mentale, 
Etudes  Psych ologiques,"  Paris,  1845;  arid  the  well-known  "Confessions  of  an  English 
Opium-Eater." 


THE   CEREBRUM,   AND   ITS   FUNCTIONS.  773 

into  objective  facts,  and  with  those  simple  teachings  of  our  own  consciousness, 
which  must,  after  all,  be  recognized  as  affording  the  ultimate  test  of  the  truth  of 
all  Psychological  doctrines.  The  Author  is  not  without  hope  that  some  approach 
to  such  a  solution  may  be  found  in  the  views  of  which  the  following  is  an  out- 
line ;  and  although  far  from  regarding  them  as  expressing  the  whole  truth,  or 
as  solving  all  the  difficulties  of  the  subject,  he  considers  that  they  express  so 
much  more  than  any  scheme  he  has  ever  heard  of,  that  he  ventures  to  request 
for  them  a  thoughtful  consideration  on  the  part  of  those  who  feel,  with  him,  the 
importance  of  attaining  some  definite  conceptions  on  this  head. — In  the  first 
place,  it  may  be  remarked  that  the  whole  tendency  of  Philosophical  Investiga- 
tion at  the  present  day  is  to  show  the  utter  futility  of  all  the  controversies  which 
have  been  carried  on  with  regard  to  the  relation  of  Mind  and  Matter.  The  essential 
nature  of  these  two  entities  is  such,  that  no  relation  whatever  can  exist  between 
them.  Matter  possesses  extension,  or  occupies  space ;  whilst  Mind  has  no  such 
property.  On  the  other  hand,  we  are  cognizant  of  Matter  only  through  its  occupa- 
tion of  space,  of  which  we  are  informed  through  our  senses ;  we  are  cognizant  of  the 
existence  of  Mind  by  our  direct  consciousness  of  feelings  and  ideas,  which  are 
to  us  the  most  certain  of  all  realities.  But,  what  is  perhaps  a  more  important 
distinction,  the  existence  of  Matter  is  essentially  passive;  left  to  itself,  it  always 
impresses  our  consciousness  in  one  and  the  same  mode  ;  and  any  change  in  its 
condition  is  the  consequence  of  external  agency.  What  have  been  termed  the 
active  states  of  matter,  are  really  the  manifestations  of  forces,  of  which  we  can 
conceive  as  having  an  existence  independent  of  matter,  and  as  having  no  other 
relation  to  it  than  that  which  consists  in  their  capability  of  changing  its  state. 
Thus  Water  continues  unchanged  so  long  as  its  temperature  remains  the  same;  but 
the  dynamical  agency  of  Heat  occasions  that  mutual  repulsion  between  its  par- 
ticles, which  transforms  it  from  a  non-elastic  liquid  into  an  elastic  vapor;  and  all 
that  heat  is  given  forth  from  it  again,  when  the  aqueous  vapor  is  transformed 
back  to  the  liquid  state.  On  the  other  hand,  the  existence  of  Mind  is  essentially 
active;  all  its  states  are  states  of  change,  and  we  know  nothing  whatever  of  it 
save  by  its  changes.  Sensations,  Perceptions,  Ideas,  Emotions,  Reasoning  pro- 
cesses, &c.,  in  fact  every  term  which  expresses  a  Mental  state,  is  a  designation 
of  a  phase  of  mental  existence  which  intervenes  between  other  phases,  in  the 
continual  succession  of  which  our  idea  of  Mind  consists. 

805.  But  whilst  between  Matter  and  Mind  it  is  utterly  vain  to  attempt  to 
establish  a  relation  of  identity  or  analogy,  a  very  close  relation  may  be  shown 
to  exist  between  Mind  and  Force.  For  in  the  first  place,  Force,  like  Mind,  can 
be  conceived  of  only  as  in  a  state  of  activity ;  and  our  idea  of  it  essentially  con- 
sists in  the  succession  of  different  states,  under  which  its  manifestations  present 
themselves  to  our  consciousness.  But,  secondly,  our  consciousness  of  Force  is 
almost  as  direct,  as  is  that  of  our  own  mental  states ;  our  notion  of  it  being  based 
upon  our  internal  sense  of  the  exertion  which  we  determinately  make  to  develop 
one  form  of  Force,  which  may  be  taken  as  the  type  of  all  the  rest — that,  namely, 
which  produces  or  which  resists  motion.  When  we  attempt  to  lift  a  weight, 
or  to  put  a  windlass  in  motion,  or  to  stop  a  horse  that  is  running  away,  we  are 
directly  conscious  of  a  Mental  exertion,  as  the  immediate  and  invariable  ante- 
cedent .of  the  development  of  motor  power  through  the  contraction  of  our  mus- 
cles; and  the  connection  of  the  two  is  further  established  by  that  "  sense  of 
effort"  which  we  intuitively  refer  to  the  muscles  themselves,  arising  as  it  does 
from  their  own  condition  (§  754) ;  and  thus  we  are  led  to  feel  that,  in  this  par- 
ticular case,  Force  must  be  regarded  as  the  direct  expression  or  manifestation  of 
that  Mental  state  which  we  call  Will.  The  analogy  becomes  stronger,  when  we 
trace  it  into  the  relations  which  these  two  agencies  respectively  bear  to  Matter. 
For  in  the  phenomenon  of  Voluntary  movement,  we  can  scarcely  avoid  seeing  that 
Mind  is  one  of  the  dynamical  agencies  which  is  capable  of  acting  on  Matter ; 


774  OF  THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

and  that,  like  other  such  agencies,  the  mode  of  its  manifestation  is  affected  by 
the  nature  of  the  material  substratum  through  which  its  influence  is  exerted. 
Thus,  the  Physiologist  knows  full  well  that  the  immediate  operation  of  the  Will 
is  not  upon  the  Muscles,  but  upon  the  Brain,  wherein  it  excites  that  active  state 
of  Nervous  matter,  which  he  designates  as  the  operation  of  Nerve-force ;  and 
that  the  propagation  of  this  force  along  the  Nerve-trunks  is  the  determining 
cause  of  the  Muscular  contraction,  which  is  the  immediate  source  of  the  motor 
power.  He  knows,  too,  that  this  dynamical  metamorphosis  is  effected  (like 
every  other  analogous  change)  by  the  intermediation  of  a  peculiar  material 
substratum,  which  itself  undergoes  a  change  of  condition ;  the  components  both 
of  the  Nervous  and  Muscular  substances  ceasing  to  exist  under  their  previous 
forms,  and  entering  into  new  combinations. — Thus,  then,  we  have  evidence,  in 
what  we  know  of  the  physiological  conditions  under  which  Mind  produces  Motion, 
that  certain  forms  of  Vital  Forces  constitute  the  connecting  link  between  the 
two ;  and  it  is  difficult  to  see  that  the  dynamical  agency  which  we  term  Will  is 
more  removed  from  Nerve-force,  on  the  one  hand,  than  Nerve-force  is  removed 
from  Motor  force  on  the  other.  Each,  in  giving  origin  to  the  next,  is  itself  ex- 
pended, or  ceases  to  exist  as  such;  and  each  bears,  in  its  own  intensity,  a  precise 
relation  to  that  of  its  antecedent  and  its  consequent. — But  we  have  not  only  evi- 
dence of  the  excitement  of  Nerve-force  by  Mental  agency;  the  converse  is  equally 
true,  Mental  activity  being  excited  by  Nerve-force.  For  this  is  the  case  in  every 
act  in  which  our  Consciousness  is  excited  through  the  instrumentality  of  the 
Sensorium,  whether  its  condition  be  affected  by  impressions  made  upon  Organs 
of  Sense,  or  by  changes  in  the  state  of  the  Cerebrum  itself;  a  certain  active  condi- 
tion of  the  nervous  matter  of  the  Sensorium,  being  (we  have  every  reason  to  be- 
lieve) the  immediate  antecedent  of  all  consciousness,  whether  sensational  or 
ideational.  And  thus  we  are  led  to  perceive  that,  as  the  power  of  the  Will  can 
develop  Nervous  activity,  and  as  Nerve-force  can  develop  Mental  activity,  there 
must  be  a  Correlation  between  these  two  modes  of  dynamical  agency,  which  is 
not  less  intimate  and  complete  than  that  which  exists  between  Nerve-force  on 
the  one  hand,  and  Electricity  or  Heat  on  the  other  (§  365).  This  idea  of  Cor- 
relation of  Forces  will  be  found  completely  to  harmonize  with  those  phenomena 
already  referred  to,  which  unmistakably  indicate  the  influence  of  physical  con- 
ditions in  the  determination  of  mental  states  (§  803) ;  whilst,  on  the  other 
hand,  it  explains  that  relation  between  Emotional  excitement  and  bodily  change, 
which  is  manifested  in  the  subsidence  of  the  former  when  it  has  expended  itself 
in  the  production  of  the  latter  (§  797).  And  further,  it  will  be  found  no  less 
applicable  to  the  explanation  of  all  that  automatic  action  of  the  Mind,  which 
consists  in  the  succession  of  ideas,  according  to  certain  "  laws  of  thought/'  with- 
out the  exercise  of  any  control  or  direction  on  the  part  of  the  individual  to  whose 
consciousness  they  present  themselves,  and  which  manifests  itself  in  the  action  of 
those  ideas  upon  the  centres  of  movement.  For  this  succession  must  be  regarded 
as  the  exponent  of  a  series  of  changes  taking  place  in  the  Cerebrum  itself,  in 
respondence  to  impressions  made  upon  it;  whilst  the  motions  which  proceed  from 
these  must  be  considered  as  being  no  less  the  results  of  its  "  reflex"  operation, 
than  are  the  "consensual"  of  the  reflex  action  of  the  Sensory  Ganglia,  and  the 
"  excito-motor"  of  that  of  the  Spinal  Cord.1  For  all  Physiological  purposes,  then, 

1  The  application  of  the  doctrine  of  "reflex  action"  to  the  Brain  was  fully  developed 
by  Dr.  Laycock  of  York,  in  a  paper  "  On  the  Reflex  Function  of  the  Brain,"  read  before 
the  Medical  Section  of  the  British  Association  at  its  meeting  in  York,  Sept.  1844,  and  after- 
wards published  in  the  "  Brit,  and  For.  Med.  Rev.,"  vol.  xix. — Not  having;  recognized  what 
appears  to  the  Author  the  essential  distinction,  both  in  their  anatomical  and  physiological 
relations,  between  the  Sensory  Ganglia  and  the  Cerebrum  or  Hemispheric  Ganglia,  Dr. 
Laycock  did  not  mark  out  the  distinction  between  the  "  sewsorz-motor"  or  "consensual" 
actions,  which  are  the  manifestations  of  the  reflex  power  of  the  former,  and  the  "  ideo- 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  775 

we  may  consider  the  nervous  matter  of  the  Cerebrum  as  the  material  substratum 
through  which  the  metamorphosis  of  Nerve-force  into  Mind-force,  and  of  Mind- 
force  into  Nerve-force,  is  effected ;  and,  as  every  such  metamorphosis  involves, 
like  other  analogous  transformations,  a  change  in  the  state  of  the  matter  through 
which  it  is  effected,  so  should  we  expect  that  Mental  activity  would  involve  the 
disintegration  of  the  Nervous  substance  which  thus  ministers  to  it :  and  such 
appears  (§§  358-362),  from  a  variety  of  evidence,  to  be  really  the  case. 

806.  It  is  obvious  that  the  view  here  taken  does  not  in  the  least  militate 
against  the  idea  that  Mind  may  have  an  existence  altogether  independent  of 
the  Material  body  through  which  it  here  manifests  itself.     All  which  has  been 
contended  for  is  that  the  connection  between  the  Mind  and  Body  is  such,  that 
each  has,  in  virtue  of  its  constitution,  a  determinate  relation  to  the  other,  in 
this  present  state  of  existence  (which  is  all  of  which  Science  can  legitimately 
take  cognizance)  j  and  that  the  actions  of  our  Minds,  in  so  far  as  they  are  car- 
ried on  without  any  interference  from  our  Will,  may  be  considered  (in  the  lim- 
ited sense  formerly  explained,  §  395)  as  functions  of  the  Cerebrum. — On  the 
other  hand,  in  the  control  and  direction  which  the  Will  has  the  power  of  ex- 
erting over  the  course  of  the  thoughts,  we  have  the  evidence  of  a  new  and  in- 
dependent power,  which  is  entirely  opposed  in  its  very  nature  to  all  the  auto- 
matic tendencies,  and  which,  according  as  it  is  habitually  exerted,  tends  to  render 
the  individual  a  free  agent.     And,  truly,  in  the  existence  of  this  Power,  which 
is  capable  of  dominating  over  the  very  highest  of  those  operations  that  we  know 
of  as  connected  with  corporeal  states,  we  find  a  better  evidence  than  we  gain 
from  the  study  of  any  other  part  of  our  psychical  nature,  that  there  is  an  entity 
wherein  Man's  nobility  essentially  consists,  which  does  not  depend  for  its  exist- 
ence on  any  play  of  physical  or  vital  forces,  but  makes  these  subservient  to  its 
determinations.     It  is,  in  fact,  in  virtue  of  the  Will,  that  we  are  not  mere  think- 
ing automata,  mere  puppets  to  be  pulled  by  suggesting-strings,  capable  of  being 
played  upon  by  every  one  who  shall  have  made  himself  master  of  our  springs 
of  action.     It  may  be  freely  admitted  that  such  thinking  automata  do  exist : 
for  there  are  many  individuals  whose  Will  has  never  been  called  into  due  exer- 
cise, and  who  gradually  almost  entirely  lose  the  power  of  exerting  it,  becoming 
the  mere  creatures  of  habit  and  impulse;  and  there  are  others  in  whom  (as  we 
shall  hereafter  see)  such  states  are  of  occasional  occurrence ;  whilst  in  others, 
again,  they  may  be  artificially  induced.     And  it  is  by  the  study  of  those  states 
in  which  the  Will  is  completely  in  abeyance — the  course  of  thought  being  en- 
tirely determined  by  the  influence  of  suggestions  upon  the  Mind,  whose  mode 
of  reaction  upon  them  depends  upon  its  original  peculiarities  and  subsequently 
acquired  habits — and  by  the  comparison  of  such  states  with  that  in  which  an 
individual,  in  full  possession  of  all  his  faculties,  and  accustomed  to  the  habitual 
control  and  direction  of  his  thoughts,  determinately  applies  his  judgment  to  the 
formation  of  a  decision  between  various  plans  of  action,  involving  the  appreciation 
of  opposing  motives — that  we  shall  obtain  the  most  satisfactory  ideas  of  what 
share  the  Will  really  takes  in  the  operations  of  our  minds  and  in  the  direction 
of  our  conduct,  and  of  what  must  be  set  down  to  the  Automatic  operation  of  our 
psychical  nature. 

807.  We  shall  now  briefly  pass  in  review  the  chief  of  those  modes  of  Psychical 
activity,  which  constitute  in  the  aggregate  what  we  are  accustomed  to  term  the 
Intellectual  Powers.     And  the  first  of  these  in  order  of  development,  and  that 
which  lies  at  the  foundation  of  all  the  rest,  is  the  Association  of  Ideas,  that  is, 

motor"  actions  which  depend  upon  the  reflex  action  of  the  latter.  But  in  adopting  that 
part  of  it  which  is  strictly  applicable  to  the  Cerebrum,  and  in  applying  it  to  those  various 
states  which  agree  in  the  common  characteristic  of  the  existence  of  Mental  Activity  with- 
out Volitional  control,  the  Author  considers  that  he  is  merely  giving  greater  definiteness 
and  a  wider  application  to  Dr.  Laycock's  doctrine. 


776  OF   THE   FUNCTIONS    OF   THE    NERVOUS    SYSTEM. 

the  formation  of  such  a  connection  between  two  or  more  ideas,  that  the  con- 
sciousness of  one  tends  to  bring  the  other  also  before  the  consciousness ;  or,  in 
other  words,  each  tends  to  suggest  the  other.  Certain  laws  of  Association, 
expressive  of  the  conditions  under  which  this  connection  is  formed,  and  the 
mode  in  which  it  acts,  have  been  laid  down  by  Psychologists ;  and  these  may 
be  concisely  stated  as  follows  :  1.  Law  of  Contiguity.  Two  or  more  states  of 
consciousness,  habitually  existing  together  or  in  immediate  succession,  tend  to 
cohere,  so  that  the  future  occurrence  of  any  one  of  them  is  sufficient  to  restore 
or  revive  the  other.  Tt  is  thus  (to  take  a  simple  illustration)  that  the  im- 
pressions made  upon  our  sensational  consciousness  by  natural  objects,  which  are 
usually  received  through  two  or  more  senses  at  once,  are  compacted  into  those 
aggregate  notions,  which,  however  simple  they  may  appear,  are  really  the  result 
of  the  intimate  combination  of  many  distinct  states  of  ideation.  Thus  our 
notion  of  the  form  of  an  object  is  made  up  of  separate  notions  derived  from  the 
visual  and  muscular  senses  respectively;  our  notion  of  the  character  of  its 
surface,  from  the  combination  of  impressions  received  through  the  visual  and 
tactile  senses ;  and  with  both  of  these  our  notion  of  color,  as  in  the  case  of  an 
orange,  may  be  so  blended,  that  we  do  not  readily  conceive  of  its  characteristic 
form  and  surface,  without  also  having  before  our  minds  the  hue  with  which 
these  have  been  always  associated  in  our  experience.  So,  again,  the  external 
aspect  of  a  body  suggests  to  our  minds  its  internal  arrangement  and  qualities, 
such  as  we  have  before  found  them  invariably  to  be ;  thus,  to  use  the  preceding 
illustration,  the  shape  and  color  of  the  orange  bring  before  our  consciousness  its 
fragrant  odor  and  agreeable  taste,  as  well  as  the  internal  structure  of  the  fruit. 
And  our  notion  of  an  orange  must  be  considered  as  the  aggregate  of  all  the 
preceding  ideas. — Not  only  the  different  ideas  excited  by  one  object,  but  those 
called  up  by  objects  entirely  dissimilar,  may  thus  come  to  be  associated,  provided 
that  the  mind  has  been  accustomed  to  the  presentation  of  them  in  frequent 
contiguity  one  with  the  other.  Such  conjunctions  may  be  natural,  that  is,  they 
may  arise  out  of  the  "  order  of  nature;"  or  they  may  be  artificial,  being  due  to 
human  arrangements ;  all  that  is  requisite  is,  that  they  should  have  sufficient 
permanence  and  constancy  to  habituate  our  minds  to  the  association. — Of  this 
law  of  contiguity,  moreover,  we  have  a  most  important  example  in  the  association 
which  the  mind  early  learns  to  form  between  successive  events,  so  that,  when  the 
first  has  been  followed  by  the  second  a  sufficient  number  of  times  to  form  the 
association,  the  occurrence  of  the  first  suggests  the  idea  of  the  second ;  if  that 
idea  be  verified  by  its  occurrence,  a  definite  expectation  is  formed ;  and  if  that 
expectation  be  unfailingly  realized,  the  idea  acquires  the  strength  of  a  belief. 
And  thus  it  is  that  we  come  to  acquire  that  part  of  the  notion  of  "  cause  and 
effect,"  which  consists  in  invariable  and  necessary  sequence  (see  p.  34),  and  to 
form  our  fundamental  conception  of  the  invariability  of  Nature.  It  is  by  the 
same  kind  of  operation,  again,  that  we  come  to  employ  words  as  the  symbols  of 
ideas,  for  the  convenience  of  intercommunication  and  reference  (§  790);  a 
certain  number  of  repetitions  of  the  sound,  concurrently  with  the  sight  of  the 
object,  or  the  suggestion  of  the  notion  of  that  object,  being  sufficient  to  establish 
the  required  relation  in  our  minds.  Of  the  large  share  which  this  kind  of 
action  takes  in  the  operations  of  Memory  and  Recollection,  evidence  will  be 
presently  given. — The  readiness  with  which  these  Associations  are  formed 
varies  greatly  in  different  individuals  and  at  different  periods  of  life.  As  a 
general  rule,  it  is  far  greater  during  the  period  of  growth  and  development,  than 
after  the  system  has  come  to  its  full  maturity;  and  remembering  that  those  new 
functional  relations  between  other  parts  of  the  Nervous  system,  which  give  rise 
to  the  "  secondarily-automatic"  movements  or  acquired  instincts,  are  formed 
during  the  same  period,  it  seems  fair  to  surmise  that  the  substance  of  the 
Cerebrum  groics  to  the  conditions  under  which  it  is  habitually  exercised ;  and 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  777 

as  its  subsequent  nutrition  (according  to  the  general  laws  of  assimilation,  §  591) 
takes  place  on  the  same  plan,  we  can  understand  the  well-known  force  of  early 
associations,  and  the  obstinate  persistence  of  early  habits  of  thought. 

808.  But  a  not  less  important  "  tendency  to  thought/7  and  one  whose  opera- 
tion is  more  concerned  in  all  the  higher  exercises  of  our  reasoning  faculties,  is 
that  which  may  be  expressed  under  the  designation  of  the  Law  of  Similarity, 
and  which  consists  in  the  general  fact  that  any  present  state  of  consciousness 
tends  to  revive  previous  states  that  are  similar  to  it.  It  is  thus  that  we  instinct- 
ively invest  a  new  object  with  the  attributes  we  have  come  to  recognize  in  one 
that  we  have  previously  examined,  to  which  the  new  object  bears  such  a  re- 
semblance, that  the  sight  of  the  latter  suggests  those  ideas  which  our  minds 
connect  with  the  former.  Thus,  we  will  suppose  a  man  to  have  once  seen  and 
eaten  an  orange ;  when  he  sees  an  orange  a  second  time,  although  it  may  be 
somewhat  larger  or  smaller,  somewhat  rougher  or  smoother,  somewhat  lighter 
or  darker  in  hue,  he  recognizes  it  as  an  orange,  and  mentally  assigns  to  it  the 
fragrance  and  sweetish  acidity  of  the  one  which  he  had  previously  eaten.  But 
if,  instead  of  being  yellow,  the  fruit  were  green,  he  would  doubt  of  its  being  an 
orange;  and  if  assured  that  it  still  was,  but  had  not  come  to  maturity,  he  would 
no  longer  expect  to  find  it  sweet,  the  notion  of  intense  acidity  being  suggested 
to  his  mind  by  his  previous  experience  of  other  green  and  unripe  fruit. — It  is 
in  virtue  of  this  kind  of  action,  that  we  extend  those  elementary  notions  which 
are  primarily  excited  by  sensation,  to  new  objects.  Thus,  the  idea  of  roundness 
(like  other  notions  of  form)  is  originally  based  on  the  combination  of  the  mus- 
cular and  visual  sensations,  and  must  be  first  acquired  by  a  process  of  consider- 
able complexity;  but  when  once  derived  from  the  examination  of  a  single  object, 
it  is  readily  extended  to  other  objects  of  the  same  character. — So,  again,  it  is 
by  the  operation  of  this  mental  tendency,  that  we  recognize  similarity  where  it 
exists  in  the  midst  of  difference,  and  separate  the  points  of  agreement  from  those 
of  discordance ;  and  this,  again,  not  merely  as  regards  objects  which  are  before 
our  consciousness  at  the  same  time  or  in  close  succession,  but  also  with  regard 
to  all  past  states  of  consciousness.  It  is  thus  that  we  identify  and  compare, 
that  we  lay  the  foundations  of  classification,  and  that  we  recover  all  past  im- 
pressions which  have  anything  in  common  with  our  present  state  of  conscious- 
ness. The  intensity  of  this  tendency,  and  the  habitual  direction  which  it  takes, 
vary  extremely  in  different  individuals.  Some  have  so  great  an  incapacity  for 
recognizing  similarity,  that  they  can  only  perceive  it  when  it  is  in  marked 
prominence,  their  minds  taking  much  stronger  note  of  differences;  whilst  others 
have  a  strong  bias  for  the  detection  of  resemblances  and  analogies,  and  discover 
them  where  ordinary  minds  cannot  recognize  them.  Some,  again,  address  them- 
selves to  the  discovery  of  similarity  among  objects  of  sense,  whilst  others  study 
only  those  ideas  which  are  the  objects  of  our  internal  consciousness ;  and  it  is 
in  the  detection  of  what  is  essentially  similar  among  the  latter,  that  all  the 
higher  operations  of  the  intellect  essentially  consist.  Even  here  we  find  that 
some  are  contented  with  superficial  analogies,  whilst  others  are  not  satisfied  until 
they  have  penetrated  by  analysis  to  the  depths  of  the  subject,  and  are  able  to 
compare  its  fundamental  idea  with  others  of  like  kind. — It  is  this  habit  of  mind, 
which  is  of  essential  value  in  all  the  sciences  of  Classification  and  Induction. 
Thus,  in  the  formation  of  generic  definitions  to  include  the  characters  which  a 
number  of  objects  have  in  common,  their  subordinate  differences  being  for  a 
time  left  out  of  view,  we  are  entirely  guided  by  the  recognition  of  similarity 
between  the  objects  we  are  arranging;  and  the  same  is  the  case  in  the  formation 
of  all  the  higher  groups  of  families,  orders,  and  classes,  the  points  of  similarity 
becoming  fewer  and  fewer  as  we  proceed  to  the  more  comprehensive  groups, 
whilst  those  of  difference  increase  in  corresponding  proportion.  The  sagacity  of 
the  Naturalist  is  shown  in  the  selection  of  the  best  points  of  resemblance,  as  the 


778  OF  THE   FUNCTIONS   OF  THE   NERVOUS    SYSTEM. 

foundation  of  his  classification ;  the  value  of  characters  being  determined,  on  the 
one  hand  by  their  constancy,  and  on  the  other  by  their  degree  of  coincidence 
with  important  features  of  general  organization  or  of  physiological  history.1  In 
the  determination  of  Physical  laws,  the  process  is  somewhat  of  the  same  kind ; 
but  the  similarities  with  which  we  have  here  to  do,  are  not,  as  in  the  preceding 
case,  objective  resemblances,  but  exist  only  among  our  subjective  ideas  of  the 
nature  and  causes  of  the  phenomena  brought  under  our  consideration.  Thus, 
there  is  no  obvious  relation  between  the  fall  of  a  stone  to  the  Earth,  and  the 
motion  of  the  Moon  in  an  elliptical  orbit  around  it ;  but  the  penetrating  mind 
of  Newton  detected  a  relation  of  common  causation  between  these  two  pheno- 
mena, which  enabled  him  to  express  them  both  under  one  law.  It  was  by  a 
like  intellectual  perception  of  similarity,  that  Franklin  was  led  to  determine  the 
identity  of  lightning  with  the  spark  from  an  electrical  machine.  And  it  would 
be  easy  to  show  that  it  has  been  in  their  extraordinary  development  of  this 
power  of  recognizing  causative  similarity,  leading  to  a  kind  of  intuitive  percep- 
tion of  its  existence  where  no  adequate  ground  can  be  assigned  by  the  reason 
for  such  a  relationship,  that  those  men  have  been  eminent,  who  have  done  the 
most  to  advance  science  by  the  process  of  inductive  generalization. — The  same 
kind  of  mental  action  is  also  employed  in  the  contrary  direction  ;  namely,  in 
that  extension  of  generic  definitions  to  new  objects,  which  takes  place  upon  every 
discovery  of  a  new  species ;  and  in  that  application  of  general  laws  to  particular 
instances,  which  constitutes  deductive  reasoning.  We  may  trace  it,  again,  even 
in  the  extension  of  the  meaning  of  words  so  as  to  become  applicable  to  new 
orders  of  ideas,  in  consequence  of  the  resemblance  which  the  latter  are  felt  to 
bear  to  those  of  which  the  words  were  previously  the  symbols :  as  in  the  ap- 
plication of  the  word  "  head,"  which  primarily  designated  the  most  elevated 
part  of  the  human  body,  in  such  phrases  as  the  "  head  of  a  house,"  the  "  head 
of  a  state,"  the  "  head  of  an  army,"  the  "  head  of  a  mob,"  in  each  of  which  the 
idea  of  superiority  and  command  is  involved;  or  in  the  phrases  the  "  heads  of  a 
discourse,"  or  the  "  heads  of  an  argument,"  in  which  we  still  trace  the  idea  of 
authority  or  direction ;  or  in  the  phrases  the  "  head  of  a  table,"  the  "  head  of 
a  river,"  in  which  the  idea  of  superiority  or  origin  comes  to  be  locally  applied; 
or  in  the  "  head  of  a  bed,"  or  "  head  of  a  coffin,"  in  which  we  have  the  more 
distinct  local  association  with  the  position  of  the  head  of  man.  Of  the  foregoing 
applications,  those  first  cited  belong  to  the  nature  of  a  metaphor,  which  has  been 
described  to  be  "a  simile  comprised  in  a  word;"  and  the  judicious  use  of  meta- 
phors, which  frequently  adds  force  as  well  as  ornamental  variety  to  the  diction, 
is  most  seen  amongst  men  who  possess  a  great  power  of  bringing  together  the 
"like"  in  the  midst  of  the  "  unlike." — Every  effort,  in  fact,  to  trace  out  unity, 
consistency,  and  harmony,  in  the  midst  of  the  wonderful  and  (at  first  sight) 
perplexing  variety  of  objects  and  phenomena  amidst  which  we  are  placed,  is  a 
manifestation  of  this  tendency  of  the  Human  Mind ;  and,  when  conducted  in 
accordance  with  the  highest  teachings  of  the  Intellect,  or  guided  by  that  Intui- 
tion which  in  some  minds  supersedes  and  anticipates  all  reasoning,  it  enables  us 
to  rise  towards  the  comprehension  of  that  great  Idea  of  the  Universe,  which  we 
believe  to  exist  in  the  Divine  Mind  in  a  majestic  simplicity  of  which  we  can 
here  but  faintly  conceive,  and  of  which  all  the  phenomena  of  Nature  are  but  the 
manifestations  to  our  consciousness. — It  may  be  remarked  that  this  mode  of 
action  of  the  mind  is  in  some  degree  opposed  to  the  preceding ;  for  whilst  con- 
tiguity leads  to  the  arranging  of  ideas  as  they  happen  to  present  themselves  in 

1  Thus,  for  example,  it  is  now  generally  admitted,  amongst  Zoologists,  that  the  Impl it- 
cental  Mammalia  should  constitute  a  separate  sub-class,  in  virtue  of  the  peculiar  con- 
formation of  their  generative  apparatus,  instead  of  being  distributed  among  other  Orders, 
as  they  were  left  by  Cuvier. 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  779 

natural  juxtaposition,  and  thus  to  induce  a  routine  which  is  often  most  un- 
meaning (§  836),  similarity  breaks  through  juxtaposition,  and  brings  together 
like  objects  from  all  quarters.  And  it  is  further  to  be  observed,  that,  with  this 
purely  intellectual  operation,  there  is  frequently  associated  a  peculiar  feeling  of 
pleasure,  which  constitutes  a  true  emotional  state.  All  the  discoveries  of 
identification,  where  use  and  wont  are  suddenly  broken  through,  and  a  common 
feature  is  made  known  among  objects  previously  looked  on  as  entirely  different, 
produce  a  flash  of  agreeable  surprise,  and  the  kind  of  sparkling  cheerfulness 
that  arises  from  the  sudden  lightening  of  a  burden.  There  are  few  who  devote 
themselves  to  the  pursuit  of  Science,  who  do  not  experience  this  pleasure,  either 
from  the  detection  of  new  relations  of  similarity  by  their  own  perception  of  them, 
or  in  the  recognition  of  them  as  developed  by  others.  It  is,  however,  much 
more  intense  in  some  minds  than  in  others;  and  according  to  its  intensity,  will 
it  act  as  a  motive  in  the  prosecution  of  scientific  inquiry  amidst  discouragements 
and  difficulties.  It  is  recorded  of  Newton,  that  when  he  was  bringing  his  great 
idea  of  the  causative  relation  between  terrestrial  gravity  and  the  motions  of  the 
heavenly  bodies  to  the  test  of  calculation,  his  agitation  became  so  great  that 
he  could  not  complete  the  computation,  and  was  obliged  to  request  a  friend  to 
do  so. 

809.  Although  the  single  relations  established  between  ideas,  either  through 
contiguity  or  through  similarity,  may  suffice  for  their  mutual  connection,  yet 
that  connection  becomes  much  stronger  when  two  or  more  such  relations  exist 
consentaneously.  Thus,  if  there  be  present  to  our  minds  two  states  of  con- 
sciousness, each  of  them  associated,  either  by  contiguity  or  similarity,  with  some 
third  state  that  is  past  and  "  out  of  mind"  at  the  time,  the  compound  action  is 
more  effective  than  either  action  would  be  separately  ;  that  is,  the  separate  sug- 
gestions might  be  too  weak  to  revive  the  past  state  of  consciousness,  but  repro- 
duce it  by  acting  together.  Of  this,  which  has  been  termed  the  Law  of 
Compound  Association,  we  have  examples  continually  occurring  to  us  in  the 
phenomena  of  Memory  ;  but  it  is  especially  brought  into  operation  in  the  volun- 
tary act  of  Recollection  (§  818). — Another  mode  in  which  the  associative  tend- 
ency operates,  is  in  the  formation  of  aggregate  conceptions  of  things  that  have 
never  been  brought  before  our  consciousness  by  sensory  impressions.  This 
faculty,  which  has  been  termed  that  of  Constructive  Association,  is  the  founda- 
tion of  Imagination  ;  and  it  is  exercised  in  every  other  mental  operation  in 
which  we  pass  from  the  known  to  the  unknown.  When  we  attempt  to  form  a 
conception,  which  shall  differ  from  one  that  we  have  already  experienced  as  a 
matter  of  objective  reality,  by  the  introduction  of  only  a  single  new  element — 
as  when  we  imagine  a  brick  building  replaced  by  one  of  stone  in  every  respect 
similar  as  to  size  and  form — we  substitute  in  our  minds  the  idea  of  stone  for 
that  of  brick,  and  associate  it  by  the  principle  of  contiguity  with  those  other 
ideas,  of  which  that  of  the  whole  building  is  an  aggregate.  So,  again,  if  we 
conceive  a  known  building  transferred  from  its  actual  site  to  some  other  already 
known  to  us,  we  dissociate  the  existing  combinations,  and  keep  together  the 
ideas  which  were  previously  separated,  until  their  contiguity  has  so  intimately 
united  them,  that  the  picture  of  the  supposed  combination  may  present  itself  to 
the  mind  exactly  as  if  it  had  been  a  real  scene  which  we  had  long  and  familiarly 
known.  By  a  further  extension  of  the  same  power,  we  may  conceive  the  ele- 
ments to  be  varied,  as  well  as  the  mode  of  their  combination ;  and  thus  we  may 
bring  before  our  consciousness  a  representation,  in  which  no  particular  has  ever 
been  before  our  minds  under  any  similar  aspect,  and  which  is,  therefore,  as  a 
ivholc,  entirely  new  to  us,  notwithstanding  that,  when  we  decompose  it  into  its 
ultimate  elements,  we  shall  find  that  each  of  these  has  been  previously  before 
our  consciousness.  Such  a  representation,  by  being  continually  dwelt  on,  may 
come  to  have  all  the  force  and  vividness  of  one  derived  from  an  actual  sensory 


730  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

impression  ;  and  we  can  scarcely  conceive  but  that  the  actual  state  of  the  Sen- 
sorium  itself  must  be  the  same  in  both  cases,  though  this  state  is  induced  in  the 
one  case  by  an  act  of  Mind,  and  in  the  other  by  Material  conditions.  A  very 
common  modus  operandi  of  this  "  constructive  association''  is  the  realization 
of  a  landscape,  a  figure,  -or  a  countenance,  from  a  pictorial  representation  of  it. 
Every  picture  must  be  essentially  defective  in  some  of  the  attributes  of  the  ori- 
ginal, as,  for  example,  in  the  representation  of  the  projection  of  objects ;  and 
all,  therefore,  that  the  picture  can  do  is  to  suggest  to  the  mind  an  idea,  which 
it  completes  for  itself  by  this  constructive  process,  so  as  to  form  an  aggregate 
which  may  or  may  not  bear  a  resemblance  to  the  original,  according  to  the 
fidelity  of  the  picture,  and  the  mode  in  which  it  acts  upon  the  mind  of  the  in- 
dividual. Thus  to  one  person  a  mere  sketch  shall  convey  a  much  more  accu- 
rate notion  of  the  object  represented,  than  a  more  finished  picture  shall  give  to 
another;  because,  from  practice  in  this  kind  of  mental  reconstruction,  the  for- 
mer recognizes  the  true  meaning  of  the  sketch,  and  fills  it  up  in  his  "  mind's 
eye ;"  whilst  the  latter  can  see  little  but  what  is  actually  before  his  bodily 
vision,  and  interprets  as  a  literal  presentation  that  which  was  intended  merely 
as  a  suggestion.  And  it  is  now  generally  admitted  that  in  all  the  higher  forms 
of  representative  Art,  the  aim  should  be,  not  to  call  into  exercise  the  faculty  of 
mere  objective  realization,  but  to  address  that  higher  power  of  idealization, 
which  invests  the  conception  suggested  by  the  representation  with  attributes 
more  exalted  than  those  actually  possessed  by  the  original,  yet  not  inconsistent 
with  them.  It  depends,  however,  as  much  on  the  mind  of  the  individual  ad- 
dressed, as  on  that  of  the  Artist  himself,  whether  such  conceptions  shall  be 
formed  ;  since  by  those  who  do  not  possess  this  power,  the  highest  work  of  Art 
is  only  appreciated,  in  so  far  as  it  enables  them  to  realize  the  object  which  it 
may  represent. 

810.  Having  thus  pointed  out  what  may  be  considered  the  most  elementary 
forms  of  Mental  Action,1  we  shall  briefly  pass  in  review  those  more  complex 
operations,  which  may  be  regarded  as  in  great  part  compounded  of  them.     The 
capacity  for  performing  these  is  known  as  the  Intellect  or  the  Reasoning  Power ; 
and  the  capacities  for  those  various  forms  of  Intellectual  activity,  which  it  is 
convenient  to  distinguish  for  the  sake  of  making  ourselves  more  fully  acquainted 
with  them,  are  termed  Intellectual  Faculties.     It  appears  to  the  author,  how- 
ever, to  be  a  fundamental  error  to  suppose  that  the  entire  Intellect  can  be  split 
up  into  a  certain  number  of  faculties }  for  each  faculty  that  is  distinguished  by 
the  Psychologist,  expresses  nothing  else  than  a  mode  of  activity,  in  which  the 
whole  power  of  the  mind  may  be  engaged  at  once — just  as  the  whole  power  of 
the  locomotive  steam-engine  may  be  employed  in  carrying  it  forwards  or  back- 
wards, according  to  the  direction  given  to  its  action.     And  if  this  be  true,  it 
must  be  fundamentally  erroneous  to  attempt  to  parcel  out  the  Cerebrum  into 
distinct  "  organs"  for  these  respective  faculties ;  the  whole  of  it  (so  far  as  we 
can  form  a  judgment)  being  called  into  operation  in  every  kind  of  mental 
activity. 

811.  That  state  in  which  the  consciousness  is  actively  directed  to  a  Sensorial 
change — whether  this  change  originate  in  impressions  received  through  the  ex- 
ternal organs  of  sense,  or  in  operations  of  the  Cerebrum — is  termed  Attention. 
Like  the  other  states  of  Mental  Activity,  which  will  come  under  our  considera- 
tion, it  may  be  either  voluntary  or  automatic  ;  that  is,  we  may  either  "  fix  our 
attention"  on  an  object  of  consciousness  by  an  effort  of  the  Will,  or  the  atten- 

1  In  the  foregoing  brief  exposition  of  the  laws  and  leading  phenomena  of  Mental  As- 
sociation, the  author  .has  derived  great  aid  from  the  excellent  article  on  "The  Human 
Mind,"  contributed  to"  Messrs.  Chambers's  "Information  for  the  People,"  by  his  friend  Mr. 
Alexander  Bain. — Though  not  agreeing  with  all  the  views  expressed  in  that  article,  the 
author  can  cordially  recommend  the  perusal  of  it  to  his  readers. 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  781 

tion  may  be  drawn  towards  it  by  the  attractive  qualities  of  the  object  itself,  and 
may  be  held  to  it  until  it  is  intentionally  detached,  or  until  the  mind  has  be- 
come satisfied  by  the  persistence  of  one  kind  of  impression.  The  intentional 
direction  of  the  attention  to  external  objects  is  what  is  commonly  known  as 
Observation ;  those  men  being  designated  as  "  observant,"  who  do  not  allow 
their  attention  to  be  so  far  engrossed  by  one  object  or  occurrence,  or  (as  very 
frequently  happens)  by  their  own  trains  of  thought,  as  to  exclude  the  cogni- 
zance of  what  may  be  taking  place  around  them ;  whilst  those  are  spoken  of  as 
"  unobservant,"  who,  by  allowing  their  consciousness  to  remain  fixed  upon  some 
one  object  or  train  of  thought,  prevent  it  from  receiving  a  legitimate  degree  of 
influence  from  other  impressions  received  and  transmitted  to  the  Sensorium  by 
the  organs  of  sense.  We  shall  hereafter  (CHAP,  xv.,  Sect.  1)  more  particularly 
examine  the  remarkable  influence  of  Attention  in  augmenting  the  acuteness  of 
sensory  impressions;  but  it  may  be  here  remarked,  that  the  same  influence  ex- 
tends itself  to  the  perception  of  our  own  mental  states;  and  that,  as  will  be 
presently  shown  (§  817),  it  is  in  the  degree  of  Attention  which  we  automati- 
cally or  voluntarily  bestow  on  certain  ideas  presented  to  us  by  suggestion, 
that  those  peculiar  modes  of  thought,  which  are  sometimes  termed  Intellectual 
Faculties,  essentially  consist. — The  intentional  direction  of  the  consciousness  to 
what  is  passing  within  us,  is  sometimes  designated  as  Reflection,  but  is  more  ap- 
propriately termed  Introspection. 

812.  The  reproduction  of  past  states  of  consciousness  by  either  of  the  forms 
of  suggestive  action  already  described,  constitutes  what  is  known  as  Memory.1 
— There  seems  much  ground  for  the  belief,  that  every  sensory  impression  which 
has  been  once  recognized  by  the  perceptive  consciousness,  is  registered  (so  to 
speak)  in  the  Cerebrum,  and  may  be  reproduced  at  some  subsequent  time, 
although  there  may  l>e  no  consciousness  of  its  existence  in  the  mind  during 
the  whole  intermediate  period.  Instances  are  of  very  frequent  occurrence,  in 
which  ideas  come  up  before  the  mind  during  delirium  or  dreaming,  and  are  ex- 

•  It  is  commonly  stated  that  Memory  consists  in  the  renewal  of  past  sensations  and  of 
the  ideas  they  have  excited ;  but  it  may  be  questioned  whether  we  primarily  retain  any- 
thing else  than  the  impressions  left  by  ideas,  and  whether  the  recall  of  sensations  is  not  a 
secondary  change,  dependent  upon  the  reaction  of  ideational  (Cerebral)  changes  upon  the 
Sensorium.  For  if  we  wish  to  reproduce  any  sensational  state — whether  visual,  auditory, 
olfactive,  gustative,  or  tactile — we  first  recall  the  notion  of  some  object  by  which  that  state 
was  formerly  produced;  and  it  is  only  by  keeping  that  notion  strongly  before  our  conscious- 
ness, that  we  can  bring  ourselves  to  see,  hear,  smell,  taste,  or  feel,  that  which  we  desire 
to  experience.  Indeed,  it  is  not  every  one  who  can  thus  reproduce  sensational  states,  the 
general  notion  being  most  commonly  all  that  is  arrived  at;  of  this  we  have  a  good  illus- 
tration in  the  conception  we  form  of  the  face  of  an  absent  friend,  it  being  only  a  com- 
paratively small  number  of  persons  who  are  able  to  reproduce  the  visual  image  with 
sufficient  distinctness  to  serve  as  a  model  for  delineation,  although  a  much  larger  number 
would  be  able  to  say  how  far  such  a  delineation  realized  their  own  conception  of  the 
countenance,  and  to  point  out  in  what  it  might  depart  from  this.  It  is  a  further  con- 
firmation of  this  view,  that  the  expression  of  a  countenance,  which  directly  appeals  to  our 
ideational  consciousness,  is  much  more  distinctly  remembered  by  most  persons  than  the 
features,  the  recognition  of  which  is  more  dependent  upon  the  recall  of  antecedent  sensa- 
tional states. — What  is  true  of  the  act  of  Recollection  in  this  particular  is  probably  true 
also  in  a  great  degree  of  spontaneous  Memory ;  but  perhaps  we  should  admit  that  the 
renewal  of  past  states  of  sensational  consciousness  may  be  effected  by  fresh  sensory  im- 
pressions which  are  closely  allied  to  them ;  as  would  seem  probable  from  the  fa.ct  that  wo 
find  ourselves  comparing  the  new  sensations  with  the  old,  without  having  in  the  mean 
time  formed  any  distinct  conception  of  the  object  by  which  the  old  were  produced. — It 
may,  however,  be  pretty  certainly  affirmed  that  the  Sensory  Ganglia  do  not  themselves 
register  sensory  impressions;  and  that  these  can  only  be  reproduced  afresh  by  external 
objects,  or  by  the  occurrence  of  ideational  changes  in  the  Cerebrum.  On  the  other  hand, 
the  Cerebrum  seems  to  act  quite  independently  of  the  Sensory  Ganglia,  in  reproducing 
ideas;  save  in  so  far  as  the  results  of  its  action  must  (on  the  theory  advanced)  be  im- 
pressed on  the  Sensorium,  before  we  can  be  rendered  conscious  of  them. 


782  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

pressed  at  the  time  or  are  subsequently  remembered,  although  the  individual 
cannot  himself  retrace  them  as  having  ever  before  been  present  to  his  conscious- 
ness ;  they  being  yet  proved  to  have  been  so  at  some  long  antecedent  period. 
A  very  extraordinary  case  of  this  kind  has  been  recorded,  in  which  a  woman, 
during  the  delirium  of  fever,  continually  repeated  sentences  in  languages  un- 
known to  those  around  her,  which  were  found  to  be  Hebrew  and  Chaldaic  ;  of 
these  she  stated  herself,  on  her  recovery,  to  be  perfectly  ignorant;  but  on  trac- 
ing her  former  history,  it  was  ascertained  that,  in  early  life,  she  had  lived  as 
servant  with  a  clergyman,  who  had  been  accustomed  to  walk  up  and  down  his 
passage,  repeating  or  reading  aloud  sentences  in  these  languages,  which  she 
must  have  retained  in  her  memory  unconsciously  to  herself. — Of  the  nature  of 
the  change  by  which  sensory  impressions  are  thus  registered,  it  seems  in  vain 
to  speculate ;  there  can  be  little  question,  however,  that  it  is  in  some  way  de- 
pendent upon  the  nutrition  of  the  Cerebrum,  since  we  see  that  alterations  in 
that  function  have  a  marked  effect  upon  the  Memory.  Thus,  in  the  case  just 
cited,  we  can  scarcely  doubt  that  some  alteration  either  in  the  circulation  of  the 
blood  through  the  cortical  substance  of  the  Cerebrum,  or  in  the  quality  of  the 
fluid,  was  the  cause  of  changes,  which,  transmitted  downwards  'to  the  Sensorium, 
reproduced  the  former  sensations;  just  as  a  disturbance  of  the  circulation  in  the 
retina  produces  the  sensation  of  flashes  of  light  or  other  visual  phenomena. 
Again,  it  is  certain  that  disease  or  injury  of  the  Cerebrum  may  destroy  the 
Memory  generally,  or  may  affect  it  in  various  remarkable  modes.  Thus  we  not 
unfrequently  meet  with  cases,  in  which  the  brain  has  been  weakened  by  attacks 
of  epilepsy  or  apoplexy  in  such  a  manner  as  to  prevent  the  reception  of  any 
new  impressions ;  so  that  the  patient  does  not  remember  anything  that  passes 
from  day  to  day ;  whilst  the  impressions  of  events  which  happened  long  before 
the  commencement  of  his  malady,  recur  with  greater  vividness  than  ever.  On 
the  other  hand,  the  memory  of  the  long  since  past  is  sometimes  entirely  de- 
stroyed ;  whilst  that  of  events  which  have  happened  subsequently  to  the  malady, 
is  but  little  weakened.  The  memory  of  particular  classes  of  ideas  is  frequently 
destroyed ;  that  of  a  certain  language,  or  some  branch  of  science,  for  example. 
The  loss  of  the  memory  of  words  is  another  very  curious  form  of  this  disorder, 
which  not  unfrequently  presents  itself :  the  patient  understands  perfectly  well 
what  is  said,  but  is  not  able  to  reply  in  any  other  terms  than  yes  or  no- — not 
from  any  paralysis  of  the  muscles  of  articulation,  but  from  the  incapability  of 
expressing  the  ideas  in  language.  Sometimes  the  memory  of  a  particular  class 
of  words  only,  such  as  nouns  or  verbs,  is  destroyed  ;  or  it  may  be  impaired 
merely,  so  that  the  patient  mistakes  the  proper  terms,  and  speaks  a  most  curious 
jargon.  So,  again,  a  person  may  remember  the  letters  of  which  a  word  is  com- 
posed, and  may  be  able  to  spell  his  wants,  though  he  cannot  speak  the  word 
itself ;  asking  for  bread  (for  example)  by  the  separate  letters  b,  r,  e,  a,  d.  A 
very  curious  affection  of  the  memory  is  that  in  which  the  sound  of  spoken  words 
does  not  convey  any  idea  to  the  mind ;  yet  the  individual  may  recognize  in  a 
written  or  printed  list  of  words,  those  which  have  been  used  by  the  speaker ; 
and  the  sight  of  them  enables  him  to  understand  their  meaning.  Conversely, 
the  sound  of  the  word  may  be  remembered,  and  the  idea  it  conveys  fully  ap- 
preciated ;  but  the  visual  memory  of  its  written  form  may  be  altogether  lost, 
although  the  component  letters  may  be  recognized.  For  this  class  of  pheno- 
mena, in  which  there  is  rather  a  severance  of  the  associative  connections  that 
have  been  formed  between  distinct  states  of  consciousness,  than  an  actual  an- 
nihilation of  the  impression  left  by  any  of  the  latter,  the  term  "  dislocation  of 
memory"  has  been  proposed  by  Dr.  Holland;1  but,  as  he  justly  remarks,  "  no 
single  term  can  express  the  various  effects  of  accident,  disease,  or  decay,  upon 

1  See  his  "  Chapters  on  Mental  Physiology,"  p.  146. 


THE   CEREBRUM,   AND   ITS   FUNCTIONS.  783 

this  faculty,  so  strangely  partial  -in  their  aspect,  and  so  abrupt  in  the  changes 
they  undergo,  that  the  attempt  to  classify  them  is  almost  as  vain  as  the  research 
into  their  cause."  It  is,  perhaps,  in  the  sudden  changes  produced  by  blows  or 
falls,  that  we  have  the  most  extraordinary  examples  of  this  kind  of  disturbance ; 
and  it  is  scarcely  less  extraordinary,  that  there  should  sometimes  be  a  no  less 
sudden  recovery  of  the  lost  impression,  which  we  can  scarcely  do  wrong  in 
attributing  to  the  return  of  the  Cerebral  organization  to  that  previous  condition 
from  which  it  had  been  perverted.— ^When  we  take  all  these  phenomena  into 
consideration,  we  can  scarcely  resist  the  conclusion  that  every  act  of  perceptive 
consciousness  produces  a  certain  modification  in  the  nutrition  of  the  Cerebrum  -, 
that  the  new  mode  of  nutrition  is  continued  according  to  the  laws  of  Assimila- 
tion already  adverted  to ;  and  that  thus  the  Cerebrum  forms  itself  in  accordance 
with  the  use  that  is  made  of  it.  And  this  unconscious  storing  up  of  impressions, 
which  can  only  be  brought  before  the  consciousness  (under  ordinary  circum- 
stances at  least)  by  the  connecting  link  of  associations,  affords  a  powerful  argu- 
ment for  the  doctrine  which  has  already  been  frequently  referred  to  as  probable 
— that  the  Cerebrum  is  not  itself  a  centre  of  consciousness,  but  that  we  only 
become  conscious  -of  its  states,  in  the  same  manner  as  we  do  of  those  of  the 
Retina  and  of  other  surfaces  for  the  reception  of  external  impressions,  by  means 
of  the  communication  of  the  changes  which  take  place  in  it  to  the  Sensorium. 

813.  Although  the  term  Memory  is  very  commonly  used  to  designate  the 
intentional  recall  of  past  states  of  consciousness,  as  well  as  their  spontaneous  or 
automatic  recurrence,  yet  it  is  properly  restricted  to  the  latter  operation ;  the 
term  recollection  being  that  which  is  appropriate  to  the  former,  whose  peculiarity 
consists  in  the  exertion  of  the  will  to  bring  that  before  the  consciousness,  which 
does  not  spontaneously  present  itself.  {Now  as  this  process  affords  a  typical 
example  of  the  mode  in  which  the  Will  acts  in  directing  the  current  of  thought, 
we  shall  examine  it  a  little  more  minutely.-£ln  the  first  place  it  may  be  posi- 
tively amrmed,  that  we  cannot  call  up  any  idea  by  simply  willing  it\  for  it  is 
a  necessary  condition  of  an  act  of  will,  that  there  should  be  in  the  mind  an  idea 
of  what  is  willed  ;  and  if  the  idea  of  the  thing  willed  be  already  in  the  mind,  it 
is  obviously  impossible  to  use  the  will  to  bring  it  there.  But  every  one  is  con- 
scious of  the  state  of  mind,  in  which  he  tries  to  remember  something  which  is 
not  at  the  time  present  to  his  consciousness ;  and  the  question  is,  how  he  pro- 
ceeds to  bring  the  idea  before  his  mind.  The  process  really  consists  in  the  fixa- 
tion of  the  attention  upon  one  or  more  ideas  already  present  to  the  mind,  which 
may  recall,  by  suggestion,  that  which  is  desiderated;  the  very  act  of  thus 
attending  to  a  particular  idea  not  only  serving  to  intensify  the  idea  itself,  but 
also  to  strengthen  the  associations  by  which  it  is  connected  with  others.  '  There 
are  certain  ideas  so  familiar  to  us,  that  they  seem  necessarily  to  recur  upon  the 
slightest  prompting  of  suggestion  ;  yet  even  with  regard  to  these,  the  voluntary 
recollection  at  any  particular  time  involves  the  process  just  described.  Thus,  if 
a  man  be  asked  his  name,  he  usually  finds  no  difficulty  in  giving  the  proper 
answer,  because  it  only  requires  that  his  attention  should  be  directed  to  the  idea 
involved  in  the  words  "  my  name,"  to  suggest  the  words  of  which  that  name 
may  consist.  But  if  the  individual  should  be  in  that  state  of  "  absence  of 
mind/'  which  really  consists  in  the  fixation  of  the  attention  upon  some  internal 
train  of  thought,  he  may  not  be  able  on  the  sudden  to  transfer  his  attention  to 
the  new  idea  that  is  forced  upon  his  consciousness  ab  externoj  and  may  thus 
hesitate  and  bungle,  before  he  is  able  to  answer  the  question  with  positiveness. 
So,  again,  it  sometimes  happens  in  old  age  that  men  fail  to  recollect  their  own 
names,  or  the  names  of  persons  most  familiar  to  them,  in  consequence  of  the 
weakening  of  the  bond  of  direct  association  ;  and  they  then  only  recall  it  by 
the  operation  to  be  presently  described.  And  there  are  states  of  mind,  in  which 
the  power  of  voluntarily  directing  the  thoughts  is  for  a  time  suspended,  and  in 


784  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

which  the  individual  cannot  make  the  slightest  effort  to  recall  the  most  familiar 
fact,  especially  if  possessed  with  the  conviction  that  such  effort  is  impossible 
(§  825). — But  supposing  the  mind  to  be  in  full  possession  of  its  ordinary 
powers,  and  the  desiderated  idea  to  be  one  which  does  not  at  once  recur  on  the 
direction  of  the  attention  to  some  idea  already  in  the  mind ;  we  then  apply  the 
same  process  to  other  ideas  which  successively  come  before  our  conscious- 
ness, selecting  those  which  we  think  most  likely  to  suggest  that  which  we 
require,  and  following  out  one  train  of  thought  after  another,  in  the  directions 
which  we  deem  most  probable,  until  we  either  succeed  in  finding  the  idea  of 
which  we  are  in  search,  or  give  up  the  pursuit  as  not  worth  further  trouble. 
Thus  a  man  who  is  making  up  his  accounts,  and  finds  that  he  has  expended  a 
sum  in  a  mode  which  he  cannot  recollect,  sets  himself  to  remember  what  busi- 
ness he  has  done,  where  he  has  recently  been,  what  shops  he  may  have  entered, 
and  so  on.  Or  when  a  man  meets  another  whom  he  recognizes  as  an  acquaint- 
ance without  remembering  his  name,  he  runs  over  a  number  of  names  (one 
being  suggested  by  another,  when  the  attention  is  given  to  them),  in  hopes  that 
some  one  of  these  may  prove  to  be  the  one,  which,  when  brought  to  his  mind, 
is  recognized  as  that  of  the  object  then  before  his  consciousness  ;  or  he  thinks 
of  the  place  in  which  he  may  have  previously  seen  him,  this  being  recalled  by 
fixing  the  attention  on  the  associations  suggested  by  the  sight  of  his  face  and 
figure,  or  by  the  sound  of  his  voice,  or  by  his  personality  altogether ;  or  he  en- 
deavors to  retrace  the  time  which  has  elapsed  since  he  last  met  with  him,  the 
persons  amongst  whom  he  then  was,  or  the  actions  in  which  he  was  engaged  ; 
that  some  one  or  other  of  these  various  associations  may  suggest  the  deside- 
rated name. — But  it  is  a  most  curious  phenomenon,  and  one  which,  though 
most  men  are  occasionally  conscious  of  it,  has  been  scarcely  recognized  by  Meta- 
physical inquirers,  that  after  all  these  expedients  have  been  employed  in  vain, 
and  the  attempt  to  bring  a  particular  idea  to  the  mind  has  been  abandoned  as 
useless,  it  will  often  occur  spontaneously  a  little  while  afterwards,  suddenly 
flashing  (as  it  were)  before  the  consciousness ;  and  this  although  the  mind  has 
been  engrossed  in  the  mean  time  by  some  entirely  different  subject  of  contempla- 
tion, and  cannot  detect  any  link  of  association  whereby  the  result  has  been  ob- 
tained, notwithstanding  that  the  whole  train  of  thought  which  has  passed 
through  the  mind  in  the  interval  may  be  most  distinctly  remembered.1  Now  it 
is  difficult,  if  not  impossible,  to  account  for  this  fact  upon  any  other  supposition, 
than  that  a  certain  train  of  action  has  been  set  going  in  the  Cerebrum  by  the 
voluntary  exertion  which  we  at  first  made;  and  that  this  train  continues  in 
movement  after  our  attention  has  been  fixed  upon  some  other  object  of  thought, 
so  that  it  goes  on  to  the  evolution  of  its  result,  not  only  without  any  continued 
exertion  on  our  own  parts,  but  also  without  our  consciousness  of  any  continued 
activity.  This  seems  to  be  one  of  the  instances  of  what  may  be  termed  uncon- 
scious cerebration,  to  which  reference  has  been  already  made  (§  787),  and  of 
which  other  examples  will  be  presently  adduced  (§§  818,  819).  But  we  may 
here  remark,  as  bearing  on  the  same  subject,  as  well  as  upon  that  of  a  preceding 
paragraph,  that  it  is  well  known  that  impressions  to  which  the  attention  is 

1  So  frequently  has  this  occurred  within  the  Author'  experience,  that  he  is  now  in  the 
habit  of  trusting  to  this  method  of  recollection,  where  he  has  reason  to  feel  sure  that  the 
desired  idea  is  not  far  off,  if  the  mind  can  only  find  its  track — as  when  it  relates  to  some 
occurrence  (such  as  a  payment  of  money)  which  is  known  to  have  taken  place  within  a 
few  days  previously ;  for  he  has  found  himself  much  more  certain  of  recovering  it,  by 
withdrawing  his  mind  from  the  search  when  it  is  not  speedily  successful,  and  by  giving 
himself  up  to  the  occupation  appropriate  to  the  time,  than  by  inducing  fatigue  by  unsuc- 
cessful eiforts.  And  this  is  not  his  own  experience  only,  but  that  of  many  others.  The 
fact  has  been  noticed  by  Dr.  Holland  ("Chapters  on  Mental  Physiology,"  p.  66);  from 
whom  he  has  learned  that  the  above  plan  has  been  put  into  successful  action  by  many  to 
whom  he  has  recommended  it. 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  785 

strongly  directed  a  short  time  before  sleep  supervenes,  are  fixed  upon  the  mind 
with  remarkable  force  ;*  a  fact  that  seems  to  indicate  that  these  impressions 
modify  the  nutrition  of  the  Brain  (which  is  taking  place  with  peculiar  activity 
during  the  state  of  mental  repose),  and  that  the  peculiar  readiness  with  which 
they  may  be  recalled  thus  depends  upon  organic  changes  of  which  we  are  un- 
conscious, rather  than  upon  any  intentional  strengthening  of  the  links  of  asso- 
ciation. 

814.  By  Attention  to  our  own  mental  states  and  operations,  a  class  of  Ideas 
is  generated,  of  a  very  different  character  from  those  which  are  called  up  by  ex- 
ternal objects ;  and  these,  being  entirely  dependent  upon  the  operation  of  the 
Intellectual  powers,  and  having  no  relation  to  sensations  except  as  the  original 
springs  of  those  operations,  may  be  termed  'intellectual  Ideas,  in  contradistinction 
to  the  sensational  Ideas.  The  former,  like  the  latter,  become  the  subjects  of  the 
associating  tendency ;  and  thus  are  combined  in  Trains  of  Thought.  Some  of  these 
intellectual  ideas  appear  to  be  so  necessarily  excited  by  mental  operations,  even  of 
the  simplest  kind,  and  to  be  so  little  dependent  on  individual  peculiarities,  either 
inherent  or  acquired,  that  they  take  rank  as  fundamental  axioms  or  principles  of 
Human  Thought.  Such  are — the  belief  in  our  ovrnpresent  existence,  or  the  faith 
which  we  repose  in  the  evidence  of  Consciousness :  this  idea  being  necessarily 
associated  with  every  form  and  condition  of  mental  activity :  the  belief  in  OUT  past 
existence,  and  in  our  personal  identity  so  far  as  our  memory  extends,  which  is 
necessarily  connected  with  the  act  of  Recollection  ;  with  this,  again,  is  connected 
the  general  idea  of  Time :  the  belief  in  the  external  and  independent  existence  of 
the  causes  of  our  sensations,  which  results  from  the  direction  of  the  mind  to  the 
Perceptional  ideas  orginating  in  them;  with  this  is  connected  the  general  idea 
of  Space  :  the  belief  in  the  existence  of  an  efficient  cause  for  the  changes  which 
we  witness  around  us,  which  springs  from  the  perception  of  those  changes ; 
whence  is  derived  our  idea  of  Power  :  the  belief  in  the  stability  of  the  order  of 
nature,  or  in  the  invariable  sequence  of  similar  effects  to  similar  causes,  which 
also  springs  directly  from  the  perception  of  external  changes,  and  seems  prior 
to  all  reasoning  upon  the  results  of  observation  of  them  (being  observed  to 
operate  most  strongly  in  those  whose  experience  is  most  scanty,  and  in  relation 
to  subjects  that  are  perfectly  new  to  them);  but  which  is  the  foundation  of  all 
applications  of  our  own  experience  or  that  of  others,  to  the  conduct  of  our  lives 
or  to  the  extension  of  our  knowledge  :  lastly,  the  belief  in  our  own  free  will,  in- 
volving the  general  idea  of  Voluntary  Power;  which  is  in  like  manner  a  direct 
result  of  our  internal  perception  of  those  mental  changes  which  are  excited  by 
sensations.  Hence  it  is  evident  that  "  the  only  foundation  of  much  of  our  belief, 
and  the  only  source  of  much  of  our  knowledge,  is  to  be  found  in  the  constitution 
of  our  own  minds;"  but  it  must  be  steadily  kept  in  view,  that  these  fundamental 
axioms  are  nothing  else  than  expressions  of  the  general  fact,  that  the  ideas  in 
question  are  uniformly  excited  (in  all  ordinarily  constituted  minds  at  least)  by 
simple  Attention  to  the  changes  in  which  they  originate. — Among  those  ele- 
mentary modes  of  thought,  which  arise  out  of  the  constitution  of  our  own  minds, 
we  must  also  rank  the  ideas  of  Truth,  Beauty,  and  Right,  which  intuitively  present 
themselves  to  our  consciousness,  in  connection  with  certain  objects  or  occurrences 
respectively  adapted  to  excite  them ;  the  first  connecting  itself  especially  with 
the  operations  of  the  Reason,  the  second  with  the  production  of  those  states  of 
feeling  which  are  termed  Sentiments,  and  the  third  with  the  determinations  of 
the  Will  in  the  guidance  of  conduct.  Truth  may  be  defined  to  be  an  apprehension 
of  the  relations  of  things  as  they  actually  exist ;  and  the  conception  of  truth, 

1  Thus  it  is  well  known  to  schoolboys  who  have  a  task  to  commit  to  memory,  that  if 
they  can  put  it  together  correctly,  however  hesitatingly,  over  night,  they  can  generally 
repeat  it  fluently  in  the  morning.  . 

50 


786  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

which  is  originally  based  upon  sensational  ideas,  comes  to  be  also  applied  to 
those  which  are  purely  intellectual  The  notion  of  Beauty  is  one  that  it  is  very 
difficult  to  define ;  but  it  seenis  to  consist  essentially  in  the  conformity  of  an 
external  object  to  a  certain  ideal  standard,  by  which  conformity  a  pleasurable 
feeling  is  produced.  That  ideal  standard  is  a  work  of  the  Imagination,  and  is 
generated  (by  a  kind  of  automatic  process)  by  the  elimination  of  all  those  ele- 
ments which  we  recognize  as  inferior,  and  by  the  intensification  and  completion 
of  all  those  which  we  regard  as  excellent.  Hence  according  to  the  aesthetic 
judgment  which  every  individual  pronounces  as  to  these  particulars,  will  be 
his  ideal  of  beauty.  The  notion  of  beauty  extends  itself,  also,  to  the  pure  con- 
ceptions of  the  Intellect;  and  thus  we  may  experience  the  sense  of  beauty  in 
the  recognition  of  a  Truth.  We  experience  the  sense  of  beauty,  too,  in  wit- 
nessing the  conformity  of  conduct  to  a  high  standard  of  Moral  excellence  ;  which 
excites  in  our  minds  a  pleasure  of  the  same  order,  as  that  which  we  derive  from 
the  contemplation  of  a  noble  work  of  art.  The  idea  of  Right  connects  itself 
with  voluntary  action.  We  have  no  feeling  of  approval  or  disapproval  with 
respect  to  actions  that  are  necessarily  connected  with  our  physical  well-being ; 
but  in  regard  to  most  of  those  which  are  left  to  our  choice,  it  is  impossible  to 
feel  indifferent ;  and  the  sphere  of  operation  of  this  principle  becomes  widened, 
in  proportion  as  the  mind  dwells  upon  the  notion  of  Moral  Obligation  which 
arises  out  of  it.  Then,  too,  the  idea  of  Right  is  brought  to  attach  itself  to 
thoughts,  as  well  as  to  actions ;  and  this,  not  merely  because  the  right  regulation 
of  the  thoughts  is  perceived  to  be  essential  to  the  right  regulation  of  the  conduct, 
but  also  because  the  mind  intuitively  perceived  that  whatever  we  can  govern 
by  the  Will  has  also  a  moral  aspect. 

815.  Closely  connected  with  many  of  the  foregoing,  and  arising  in  most 
minds  from  some  or  other  of  them  by  the  very  nature  of  our  psychical  consti- 
tution, are  those  ideas  which  relate  to  the  Being  and  attributes  of  the  Deity. 
The  conception  which  each  individual  forms  of  the  Divine  Nature  depends  in 
great  degree  upon  his  own  habits  of  thought;  but  there  are  two  extremes, 
towards  one  or  other  of  which  most  of  the  current  notions  on  this  subject  may 
be  said  to  tend,  and  between  which  they  seem  to  have  oscillated  in  all  periods 
of  the  history  of  Monotheism.  These  are,  Pantheism,  and  Anthropomorphism. 
— Towards  the  Pantheistic  aspect  of  Deity,  we  are  especially  led  by  the  philo- 
sophic contemplation  of  His  agency  in  external  Nature;  for  in  proportion  as  we 
fix  our  attention  exclusively  upon  the  "  laws"  which  express  the  orderly 
sequence  of  its  phenomena,  and  upon  the  "  forces"  whose  agency  we  recognize 
as  their  immediate  causes,  do  we  come  to  think  of  the  Divine  Being  as  the 
mere  First  Principle  of  the  Universe,  an  all-comprehensive  "  Law"  to  which 
all  other  laws  are  subordinate,  that  most  general  "  Cause"  of  which  all  the 
physical  forces  are  but  manifestations.  This  conception  embodies  a  great  truth, 
and  a  fundamental  error.  Its  truth  is  the  recognition  of  the  universal  and  all- 
controlling  agency  of  the  Deity,  and  of  His  presence  in  Creation  rather  than 
on  the  outside  of  it.  Its  error  lies  in  the  absence  of  any  distinct  recognition 
of  that  conscious  volitional  agency  which  is  the  essential  attribute  of  Person- 
ality; for  without  this,  the  Universe  is  nothing  else  than  a  great  self-acting 
machine,  its  Laws  are  but  the  expressions  of  "surd  necessity,"  and  all  the 
higher  tendencies  and  aspirations  of  the  Human  Soul  are  but  "  a  mockery,  a 
delusion,  and  a  snare." — The  Anthropomorphic  conception  of  Deity,  on  the 
other  hand,  arises  from  the  too  exclusive  contemplation  of  our  own  nature  as 
the  type  of  the  Divine ;  and  although,  in  the  highest  form  in  which  it  may  be 
held,  it  represents  the  Deity  as  a  being  in  whom  all  the  noblest  attributes  of 
Man's  spiritual  essence  are  expanded  to  infinity,  yet  it  is  practically  limited 
and  degraded  by  the  impossibility  of  fully  realizing  such  an  existence  to  our 
minds;  the  failings  and  imperfections  incident  to  our  Human  nature  being 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  787 

attributed  to  the  Divine,  in  proportion  as  the  low  standard  of  intellectual  and 
moral  development  in  each  individual  keeps  down  his  idea  of  possible  excellence. 
Even  the  lowest  form  of  any  such  conception,  however,  embodies  (like  the  Pan- 
theistic) a  great  truth,  though  mingled  with  a  large  amount  of  error.  It  repre- 
sents the  Deity  as  a  Person;  that  is,  as  having  that  Intelligent  Volition,  which 
we  recognize  in  ourselves  as  the  source  of  the  power  we  determinately  exert, 
through  our  bodily  organism,  upon  the  world  around;  and  it  invests  Him,  also, 
with  those  Moral  attributes,  which  place  him  in  sympathetic  relation  with  his 
sentient  creatures.  But  this  conception  is  erroneous,  in  so  far  as  it  represents 
the  Divine  nature  as  restrained  in  its  operations  by  any  of  these  limitations 
which  are  inherent  in  the  very  constitution  of  Man :  and  in  particular,  because 
it  leads  those  who  accept  it  to  think  of  the  Creator  as  "  a  remote  and  retired 
mechanism,  inspecting  from  without  the  engine  of  creation  to  see  how  it  per- 
forms," and  as  either  leaving  it  entirely  to  itself  when  once  it  has  been  brought 
into  full  activity,  or  as  only  interfering  at  intervals  to  change  the  mode  of  its 
operation. — Now  the  truths  which  these  views  separately  contain,  are  in  perfect 
harmony  with  each  other :  and  the  very  act  of  bringing  them  into  combination 
effects  the  elimination  of  the  errors  with  which  they  were  previously  associated. 
For  the  idea  of  the  universal  and  all-controlling  agency  of  the  Deity,  and  of 
his  immediate  presence  throughout  Creation,  is  not  found  to  be  in  the  least 
degree  inconsistent  with  the  idea  of  His  personality,  when  that  idea  is  detached 
from  the  limitations  which  cling  to  it  in  the  minds  of  those  who  have  not 
expanded  their  anthropomorphic  conception  by  the  scientific  contemplation  of 
Nature;  on  the  contrary,  when  we  have  once  arrived  at  that  conception  of  Force 
as  an  expression  of  Will,  which  we  derive  from  our  own  experience  of  its  pro- 
duction, the  universal  and  constantly-sustaining  agency  of  the  Deity  is  recog- 
nized in  every  phenomenon  of  the  external  Universe;  and  we  are  thus  led  to 
feel  that  in  the  Material  Creation  itself,  we  have  the  same  distinct  evidence  of 
His  personal  existence  and  ceaseless  activity,  as  we  have  of  the  agency  of  in- 
telligent minds  in  the  artistic  creations  of  Genius,  or  in  the  elaborate  contri- 
vances of  Mechanical  skill,  or  in  those  written  records  of  Thought  which 
arouse  our  own  psychical  nature  into  kindred  activity. 

816.  There  is,  in  fact,  no  part  of  Man's  psychical  nature  which  does  not 
speak  to  him  of  the  Divine,  when  it  is  rightly  questioned.  The  very  perception 
of  finite  existence,  whether  in  time  or  space,  leads  to  the  idea  of  the  Infinite. 
The  perception  of  dependent  existence  leads  to  the  idea  of  the  Self-existent. 
The  perception  of  change  in  the  external  world  leads  to  the  idea  of  an  Abso- 
lute Power  as  its  source.  The  perception  of  the  order  and  constancy  underly- 
ing all  those  diversities  which  the  surface  of  Nature  presents,  leads  to  the  idea 
of  the  Unity  of  that  power.  The  recognition  of  Intelligent  Will  as  the  source 
of  the  power  we  ourselves  exert,  leads  to  the  idea  of  a  like  Will  as  operating 
in  the  Universe.  And  our  own  capacity  for  reasoning,  which  we  know  not  to 
have  been  obtained  by  our  individual  exertions,  is  a  direct  testimony  to  the 
Intelligence  of  the  Being  who  implanted  it.  So  are  we  led  from  the  very 
existence  of  our  Moral  Feelings,  to  the  conception  of  the  existence  of  attributes, 
the  same  in  kind,  however  exalted  in  degree,  in  the  Divine  being.  The  sense 
of  Truth  implies  its  actual  existence  in  a  being  who  is  himself  its  source  and 
centre  ;  and  the  longing  for  a  yet  higher  measure  of  it,  which  is  experienced 
in  the  greatest  force  by  those  who  have  already  attained  the  truest  and  widest 
view,  is  the  testimony  of  our  own  souls  to  the  Truth  of  the  Divine  Nature. 
The  perception  of  Right,  in  like  manner,  leads  us  to  the  Absolute  lawgiver  who 
implanted  it  in  our  constitution;  and,  as  has  been  well  remarked,  "all  the 
appeals  of  innocence  against  unrighteous  force  are  appeals  to  eternal  justice, 
and  all  the  visions  of  moral  purity  are  glimpses  of  the  infinite  excellence." 
The  aspirations  of  the  most  exalted  moral  natures  after  a  yet  higher  state  of 


788  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

Holiness  and  Purity,  can  only  be  satisfied  by  the  contemplation  of  such  per- 
fection as  no  merely  Human  being  has  ever  attained;  and  it  is  only  in  the  con- 
templation of  the  Divine  Ideal,  that  they  meet  their  appropriate  object.  And 
the  sentiment  of  Beauty,  especially  as  it  rises  from  the  material  to  the  spiritual, 
passes  beyond  the  noblest  creations  of  art  and  the  most  perfect  realization  of  it 
in  the  outward  life,  and  soars  into  the  region  of  the  Unseen,  where  alone  the 
imagination  can  freely  expand  itself  in  the  contemplation  of  such  Beauty  as  no 
objective  representation  can  embody. — And  it  is  by  combining,  so  far  as  our 
capacity  will  admit,  the  ideas  which  we  thus  derive  from  reflection  upon  the 
facts  of  our  own  consciousness,  with  those  which  we  draw  from  the  contempla- 
tion of  the  Universe  around  us,  that  we  form  the  justest  conception  of  the  Divine 
Nature,  of  which  our  finite  minds  are  capable.  We  are  led  to  conceive  of  Him  as 
the  Absolute,  Unchangeable,  Self-Existent — Infinite  in  duration — Illimitable  in 
space — the  highest  ideal  of  Truth,  Right,  and  Beauty — the  All-powerful  source 
of  that  agency  which  we  recognize  in  the  phenomena  of  Nature — the  All- Wise 
designer  of  that  wondrous  plan,  whose  original  perfection  is  the  real  source  of 
the  uniformity  and  harmony  which  we  recognize  in  its  operation — the  All- 
Benevolent  contriver  of  the  happiness  of  His  sentient  creatures — the  All-Just 
disposer  of  events  in  the  Moral  world,  for  the  evolution  of  the  ultimate  ends  for 
which  Man  was  called  into  existence.  In  proportion  to  the  elevation  of  our 
own  spiritual  nature,  and  the  harmonious  development  of  its  several  tendencies, 
will  be  the  elevation  and  harmoniousness  of  our  conception  of  the  Divine ;  and 
in  proportion,  more  particularly,  as  we  succeed  in  raising  ourselves  towards  that 
ideal  of  perfection  which  has  been  graciously  presented  to  us  in  the  "  well- 
beloved  Son  of  God,"  are  the  relations  of  the  Divine  Nature  to  our  own  felt 
to  be  more  intimate.  And  it  is  from  the  consciousness  of  our  relation  to  God, 
as  His  creatures,  as  His  children,  and  as  independent  but  responsible  fellow- 
workers  with  Him  in  accomplishing  His  great  purposes,  that  all  those  Ideas  and 
Sentiments  arise,  which  are  designated  as  Religious,  and  which  constitute  that 
most  exalted  portion  of  our  nature,  of  whose  continued  existence  and  yet 
higher  elevation  we  have  the  fullest  assurance,  both  in  the  depths  of  our  own 
consciousness  and  in  the  promises  of  Revelation. 

817.  Upon  the  Sensational  and  Intellectual  Ideas  thus  brought  under  the 
cognizance  of  the  Mind,  all  acts  of  Reasoning  are  founded.  These  consist,  for  the 
most  part,  in  the  aggregation  and  collocation  of  ideas,  the  decomposition  of  com- 
plex ideas  into  more  simple  ones,  and  the  combination  of  simple  ideas  into 
general  expressions  j  in  which  are  exercised  the  faculty  of  Comparison,  by  which 
the  relations  and  connections  of  ideas  are  perceived — that  of  Abstraction,  by  which 
we  fix  our  attention  on  any  particular  qualities  of  the  object  of  our  thought, 
and  isolate  it  from  the  rest — and  that  of  Generalization,  by  which  we  connect 
together  those  properties  which  have  been  thus  discovered  to  be  common  to  a 
number  of  objects.  These  operations,  when  carefully  analyzed,  seem  capable 
of  reduction  to  this  one  expression — namely,  the  fixation  of  our  Attention  on 
some  particular  classes  of  ideas,  from  among  those  which  Suggestion  brings 
before  our  consciousness ',  and  this  fixation  may  result,  as  already  shown,  either 
from  the  peculiar  attractiveness  which  these  classes  of  ideas  have  for  us  (the 
constitution  of  individual  minds  varying  greatly  in  this  respect),  or  on  the  de- 
termination of  our  own  Will. — The  foregoing  are  the  purely  intellectual  pro- 
cesses chiefly  concerned  in  the  simple  acquirement  of  knowledge,  with  which 
class  of  operations  the  Emotional  part  of  our  nature  has  very  little  participation  ; 
and  there  is  strong  reason  to  believe  that  they  may  be  performed  automatically 
to  a  very  considerable  extent,  without  any  other  than  a  permissive  act  of  Will. 
It  is  clearly  by  such  automatic  action  that  the  above-mentioned  "fundamental 
axioms"  or  "intuitions"  are  evolved;  and  there  is  not  one  of  the  operations 
above  described,  which  may  not  be  performed  quite  involuntarily,  especially  by 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  789 

an  individual  who  is  naturally  disposed  to  it.  Thus  to  some  persons,  the  tend- 
ency to  compare  any  new  object  of  consciousness  with  objects  that  have  been 
previously  before  the  mind,  is  so  strong  as  to  be  almost  irresistible ;  and  this, 
or  any  other  original  tendency,  is  strengthened  by  the  habit  of  acting  in  con- 
formity with  it.  So,  again,  the  tendency  to  abstraction  is  equally  strong  in  the 
minds  of  others,  who  instinctively  seek  to  separate  what  is  fundamental  and 
essential  in  the  properties  of  objects,  from  what  is  superficial  and  accidental ;  and 
their  attention  being  most  attracted  by  the  former,  they  readily  recognize  the 
same  characters  elsewhere,  and  are  thus  as  prone  to  combine  and  generalize,  as 
others  are  to  analyze  and  distinguish.  It  is  only,  in  fact,  when  we  intentionally 
divert  the  current  of  thought  from  the  direction  in  which  it  was  previously  run- 
ning— when  we  determine  to  put  our  minds  in  operation  in  some  particular 
manner — and  make  a  choice  of  means  adapted  to  our  end  (as  in  the  act  of  Re- 
collection already  described)  by  purposely  fixing  our  attention  upon  one  class 
of  objects  and  excluding  others — that  we  can  be  said  to  use  the  Will  in  the 
act  of  Reasoning ;  and  this  exercise  of  it  is  shown,  by  the  analysis  of  our  own 
consciousness,  to  be  much  rarer  than  is  commonly  supposed.  Thus  we  may 
imagine  a  man  sitting  down  at  a  fixed  hour  every  day,  to  write  a  treatise  upon 
a  subject  which  he  has  previously  thought  out;  after  that  first  effort  of  Will  by 
which  his  determination  was  made,  the  daily  continuance  of  his  task  becomes  so 
habitual  to  him,  that  no  fresh  exertion  of  it  is  required  to  bring  him  to  his  desk; 
and,  unless  he  feel  unfit  for  his  work,  or  some  other  object  of  interest  tempt  him 
away  from  it,  so  that  he  is  called  upon  to  decide  between  contending  motives, 
his  Will  cannot  be  fairly  said  to  be  brought  into  exercise.  It  may  need,  per- 
haps, some  voluntary  fixation  of  his  attention  upon  the  topics  upon  which  he 
had  been  engaged  when  he  last  dropped  the  thread,  to  enable  him  to  recover  it 
so  as  to  commence  his  new  labors  in  continuity  with  the  preceding ;  but  when 
once  his  mind  is  fairly  engrossed  with  his  subject,  this  develops  itself  before 
his  consciousness  according  to  his  previous  habits  of  mental  action  ;  ideas  follow 
one  another  in  rapid  and  continuous  succession,  clothe  themselves  in  words,  and 
prompt  the  movements  by  which  those  words  are  expressed  in  writing  ;  and  this 
automatic  action  may  continue  uninterruptedly  for  hours,  without  any  tendency 
of  the  mind  to  wander  from  its  subject,  the  Will  being  only  called  into  play 
when  the  feeling  of  fatigue  or  the  distraction  of  other  objects  renders  it  difficult 
to  keep  the  attention  fixed  upon  that  which  has  previously  held  it  by  its  own 
attractive  power.1 — The  converse  of  this  condition  is  experienced  when  some 

1  Two  very  remarkable  instances  may  be  noticed,  in  men  distinguished,  the  one  for  in- 
tellectual, the  other  for  artistic  ability ;  in  both  of  whom  the  mental  action  which  evolved  the 
result  seems  to  have  been  in  great  degree  of  an  automatic  character. — All  accounts  of  Cole- 
ridge's habits  of  thought,  as  manifested  in  his  conversation  (which  was  a  sort  of  thinking 
aloud),  agree  in  showing  that  his  train  of  mental  operations,  once  started,  went  on  of  itself, 
sometimes  for  a  long  distance  in  the  original  direction,  sometimes  with  a  divergence  into 
some  other  track,  according  to  the  consecutive  suggestions  of  his  own  mind,  or  to  new  sug- 
gestions introduced  into  it  from  without.  His  whole  course  of  life  was  one  continued  proof 
of  the  weakness  of  his  Will ;  for,  with  numerous  gigantic  projects  continually  in  his  mind, 
he  could  never  bring  himself  even  seriously  to  attempt  to  execute  any  one  of  them  ;  and 
his  utter  deficiency  in  self-control  rendered  it  necessary  for  his  welfare  that  he  should  yield 
himself  to  the  control  of  others.  The  composition  of  the  poetical  fragment  "Kubla  Khan" 
in  his  sleep  is  a  typical  example  of  automatic  mental  action ;  and  almost  his  whole  life 
might  be  regarded  as  a  sort  of  waking  dream,  in  regard  to  the  deficiency  of  that  self-de- 
termining power  which  is  the  pre-eminent  characteristic  of  every  really  great  mind.  (The 
most  striking  portraiture  of  Coleridge's  habits  of  conversation  is  to  be  found  in  Carlyle's 
"Life  of  John  Sterling.") — The  whole  artistic  life  of  Mozart,  from  his  infancy  to  his  death, 
save  in  so  far  as  the  earlier  part  of  it  was  directed  by  his  father,  may  be  cited  as  an  ex- 
ample of  the  spontaneous  or  automatic  development  of  musical  ideas,  which  expressed 
themselves  in  the  language  appropriate  to  them.  When  only  four  years  old,  he  began  to 
write  music,  which  was  found  to  be  in  strict  accordance  with  the  rules  of  composition, 
although  he  had  received  no  instruction  in  these.  And  when  engaged  in  adult  life,  in  the 


790  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

powerful  interest  tends  to  draw  off  the  attention  elsewhere,  and  the  thoughts 
are  found  to  wander  continually  from  the  subject  in  hand ;  or  when,  from  the 
undue  protraction  of  mental  exertion,  the  state  of  the  brain  is  such  that  the 
thoughts  no  longer  develop  themselves  consecutively  in  the  mind,  nor  shape 
themselves  into  appropriate  forms  of  expression.  In  either  of  these  cases,  the 
intellectual  powers  can  only  be  kept  in  action  upon  the  pre-determined  subject, 
by  a  strong  effort  of  the  Will ;  of  this  effort  we  are  conscious  at  the  time,  and 
feel  that  we  need  to  put  forth  even  a  greater  power  than  that  which  would  be 
required  to  generate  a  large  amount  of  physical  force  through  the  muscular 
system ;  and  we  subsequently  experience  the  results  of  it,  in  the  feeling  of 
excessive  fatigue  which  always  follows  any  exertion  that  calls  the  Cerebrum 
into  extraordinary  activity. 

818.  But  we  seem  justified  in  proceeding  further,  and  in  affirming  that  the 
Cerebrum  may  act  upon  impressions  transmitted  to  it,  and  may  elaborate  results 
such  as  we  might  have  attained  by  the  purposive  direction  of  our  minds  to  the 
subject,  without  any  consciousness  on  our  own  parts;  so  that  we  only  become 
aware  of  the  operation  which  has  taken  place,  when  we  compare  the  result,  as 
it  presents  itself  to  our  minds  after  it  has  been  attained,  with  the  materials 
submitted  to  the  process.  The  ordinary  experience  of  most  persons  will  supply 
them  with  examples  of  this  form  of  Cerebral  activity.  One  of  the  simplest  in- 
stances of  it  is  to  be  found  in  the  process  by  which  we  acquire  a  knowledge  of 
the  meaning  of  an  author  whose  writings  we  are  perusing.  For,  if  the  subject 
be  one  into  which  we  readily  enter,  and  if  the  writer's  flow  of  thought  be  one 
which  we  easily  follow,  and  his  language  be  appropriate  to  express  his  ideas,  we 
acquire  the  meaning  of  one  sentence  after  another,  without  any  conscious 
recognition  of  the  meaning  of  each  of  the  component  words;  and  yet  it  is  cer- 
tain that  a  particular  impression  must  have  been  made  by  each  of  these  words 
upon  the  Cerebrum,  before  we  can  comprehend  the  notion  which  they  were 
collectively  intended  to  convey.  It  is  only  when  the  language  is  ill  chosen,  or 
when  we  do  not  readily  follow  the  author's  train  of  thought,  that  we  direct  our 
attention  to  the  signification  of  the  individual  words,  and  become  conscious  of 
their  separate  meaning.  In  like  manner,  an  expert  calculator  will  cast  his  eye 
rapidly  from  the  bottom  to  the  top  of  a  column  of  figures  and  will  name  the 
total,  without  any  conscious  appreciation  of  the  value  of  each  individual  figure. 
— But  in  these  instances,  no  higher  act  of  mind  is  required  than  the  production 
of  one  complex  idea  out  of  an  aggregate  of  simpler  elements;  there  are  cases, 

production  of  those  works  which  have  rendered  his  name  immortal,  it  was  enough  for  him 
once  to  fix  his  thoughts  in  the  first  instance  upon  the  subject  (the  libretto  of  an  opera,  for 
example,  or  the  words  of  a  religious  service),  so  as  to  give  the  requisite  start  and  direction 
to  his  ideas,  which  then  flowed  onwards  without  any  eifort  of  his  own ;  so  that  the  whole 
of  a  symphony  or  an  overture  would  develop  itself  in  his  mind,  its  separate  instrumental 
parts  taking  (so  to  speak)  their  respective  shapes,  without  any  intentional  elaboration.  In 
fact,  the  only  exercise  of  Will  that  seemed  to  be  required  on  his  part  consisted  in  the  not- 
ing down  of  the  composition  when  complete ;  and  this,  under  the  temptations  of  social 
intercourse,  and  a  dislike  to  anything  like  "  work,"  he  would  sometimes  postpone  until  the 
last  moment.  Thus  it  is  well  known  that  his  overture  to  Don  Giovanni  was  only  written 
out  (although  it  must  have  been  previously  composed)  during  the  night  previous  to  its 
performance,  which  took  place  without  any  rehearsal.  It  is  recorded  of  him,  that  being 
once  asked  by  an  inferior  musician  how  he  set  to  work  to  compose  a  symphony,  he  replied 
— "  If  you  once  think  of  how  you  are  to  do  it,  you  will  never  write  anything  worth  hearing.  / 
write  because  I  cannot  help  it."  Mozart,  like  Coleridge,  was  a  man  of  extremely  weak 
will ;  he  could  neither  keep  firm  to  a  resolution,  nor  resist  temptation ;  and  when  not  under 
the  guidance  of  his  excellent  wife,  was  the  sport  of  almost  every  kind  of  impulse.  But 
there  was  probably  never  a  more  remarkable  example  than  his  musical  career  presents,  of 
the  automatic  operation  of  that  creative  power  which  specially  constitutes  Genius ;  and  his 
life  is  altogether  a  most  interesting  study  to  the  Psychologist,  as  well  as  to  the  Musician. 
(See  especially  the  "Life  of  Mozart"  by  Edward  Holmes.) 


THE   CEREBRUM,   AND   ITS   FUNCTIONS.  791 

however,  in  which  processes  of  a  far  more  elaborate  nature  are  carried  on,  with- 
out necessarily  affecting  our  consciousness.  Most  persons  who  attend  to  their 
own  mental  operations  are  aware  that  when  they  have  been  occupied  for  some 
time  about  a  particular  subject,  and  have  then  transferred  their  attention  to 
some  other,  the  first  when  they  return  to  the  consideration  of  it,  may  be  found 
to  present  an  aspect  very  different  from  that  which  it  possessed  before  it  was 
put  aside ;  notwithstanding  that  the  mind  has  since  been  so  completely  en- 
grossed with  the  second  subject,  as  not  to  have  been  consciously  directed 
towards  the  first  in  the  interval.  Now  a  part  of  this  change  may  depend  upon 
the  altered  condition  of  the  mind  itself,  such  as  we  experience  when  we  take  up 
a  subject  in  the  morning  with  all  the  vigor  which  we  derive  from  the  refresh- 
ment of  sleep,  and  find  no  difiiculty  in  overcoming  difficulties  and  in  disentan- 
gling perplexities  which  checked  our  further  progress  the  night  before,  when 
we  were  too  weary  to  give  more  than  a  languid  attention  to  the  points  to  be 
made  out,  and  could  use  no  exertion  in  the  search  for  their  solutions.  But  this 
by  no  means  accounts  for  the  entirely  new  development  which  the  subject  is 
frequently  found  to  have  undergone,  when  we  return  to  it  after  a  considerable 
interval;  a  development  which  cannot  be  reasonably  explained  in  any  other 
mode,  than  by  attributing  it  to  the  intermediate  activity  of  the  Cerebrum,  which 
has  in  this  instance  automatically  evolved  the  result  without  our  consciousness. 
Strange  as  this  phenomenon  may  at  first  sight  appear,  it  is  found,  when  carefully 
considered,  to  be  in  complete  harmony  with  all  that  has  been  affirmed  in  the  pre- 
ceding paragraphs,  respecting  the  relation  of  the  Cerebrum  to  the  Sensorium, 
and  the  independent  action  of  the  former  j  and  looking  at  all  those  automatic 
operations  by  which  results  are  evolved  without  any  intentional  direction  of  the 
Mind  to  them,  in  the  light  of  "  reflex  actions"  of  the  Cerebrum,  there  is  no 
more  difficulty  in  comprehending  that  such  reflex  actions  may  proceed  without 
our  knowledge,  so  as  to  evolve  intellectual  products  when  their  results  are 
transmitted  to  the  Sensorium  and  are  thus  impressed  on  our  consciousness,  than 
there  is  in  understanding  that  impressions  may  excite  muscular  movements, 
through  the  "reflex"  power  of  the  Spinal  Cord,  without  the  necessary  inter- 
vention of  Sensation.  In  both  cases,  the  condition  of  this  form  of  independent 
activity  is  that  the  receptivity  of  the  Sensorium  shall  be  suspended  quoad  the 
changes  in  question,  either  by  the  severance  of  structural  connection,  or  through 
its  temporary  engrossment  by  other  objects.1 

819.  It  is  difficult  to  find  an  appropriate  term  for  this  class  of  operations. 
They  can  scarcely  be  designated  as  Reasoning  Processes,  since  "  unconscious 
reasoning"  is  a  contradiction  in  terms.  The  designation  Unconscious  Cerebration 
is  perhaps  less  objectionable  than  any  other. — But  it  must  not  be  left  out  of  view, 
that  emotional  states,  or  rather  states  which  constitute  emotions  when  we  become 
conscious  of  them,  may  be  developed  by  the  same  process ;  so  that  our  feelings 

1  It  may  serve  to  give  the  readers  of  this  Treatise  more  confidence  than  they  might  other- 
wise feel  in  the  truth  of  the  above  doctrine,  if  the  author  mentions  that,  having  been  led 
to  entertain  it  as  possible  on  purely  Physiological  grounds,  he  then  began  to  question  not 
merely  his  own  experience,  but  that  of  others,  as  to  the  Psychological  evidence  of  uncon- 
scious Cerebral  activity.  Having  found  enough  in  the  results  of  this  inquiry  to  convert 
the  possibility  into  a  probability,  he  next  took  an  opportunity  of  placing  his  views  before 
two  of  the  deepest  thinkers  of  the  present  day,  Sir  W.  Hamilton  and  Mr.  John  Stuart  Mill. 
From  the  former  he  learned  that  the  doctrine  had  been  advanced  by  Leibnitz  more  than 
two  centuries  since ;  and  that  the  first  of  the  above  illustrations  had  actually  been  adduced 
by  that  eminent  philosopher  in  its  support.  By  the  latter  he  was  assured  that  the  fact  of 
the  unconscious  development  of  a  subject  of  thought  was  so  familiar  to  him,  that,  when 
he  found  it  difficult  to  pursue  an  inquiry  further,  not  seeing  his  way  clearly  through  its 
entanglements,  he  was  accustomed  to  lay  it  aside  for  weeks  or  even  months,  and  to  devote 
himself  to  some  other  object,  with  the  full  expectation  (derived  from  frequent  experience) 
of  being  able  to  prosecute  his  first  investigation  with  diminished  difficulty,  whenever  he 
might  feel  disposed  to  resume  it. 


792  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

towards  persons  and  objects  may  undergo  most  important  changes,  without  our 
being  in  the  least  degree  aware,  until  we  have  our  attention  directed  to  our  own 
mental  state,  of  the  alteration  which  has  taken  place  in  them.  A  very  common 
but  very  characteristic  example  of  this  kind  of  action  is  afforded  by  the  power- 
ful attachment  which  often  grows  up  between  individuals  of  opposite  sexes, 
without  either  being  aware  of  the  fact ;  the  full  strength  of  this  attachment 
being  only  revealed  to  the  consciousness  of  each,  when  circumstances  threaten 
a  separation,  and  when  each  becomes  cognizant  of  the  feelings  entertained  by 
the  other.  The  existence  of  a  mutual  attachment,  indeed,  is  often  recognized 
by  a  bystander  (especially  if  the  perceptions  be  sharpened  by  jealousy,  which 
leads  to  an  intuitive  interpretation  of  many  minute  occurrences  which  would 
be  without  signification  to  an  ordinary  observer),  before  either  of  the  parties 
has  made  the  discovery  whether  as  regards  the  individual  self,  or  the  beloved 
object ;  the  Cerebral  state  manifesting  itself  in  action,  although  no  distinct  con- 
sciousness of  that  state  has  been  attained,  chiefly  because,  the  whole  attention 
being  attracted  by  the  present  enjoyment,  there  is  little  disposition  to  Intro- 
spection. The  fact,  indeed,  is  recognized  in  our  ordinary  language ;  for  we  con- 
tinually speak  of  the  feelings  which  we  unconsciously  entertain  towards  another, 
and  of  our  not  becoming  aware  of  them  until  some  circumstances  call  them  into 
activity.  Here,  again,  it  would  seem  as  if  the  material  organ  of  these  feelings 
tends  to  form  itself  in  accordance  with  the  impressions  which  are  habitually 
made  upon  it j  so  that  we  are  as  completely  unaware  of  the  changes  which  may 
have  taken  place  in  it,  as  we  are  of  those  by  which  passing  events  are  registered 
in  our  minds  (§  812),  until  some  circumstance  calls  forth  the  conscious  manifes- 
tation, which  is  the  u  reflex"  of  the  new  condition  which  the  organ  has  acquired. 
And  it  may  be  remarked,  in  this  connection,  that  the  Emotional  state  seems 
often  to  be  determined  by  circumstances  of  which  the  individual  has  no  distinct 
consciousness,  and  especially  by  the  emotional  states  of  those  by  whom  he  is 
surrounded ;  a  mode  of  influence  which  is  exerted  with  peculiar  potency  on 
the  minds  of  children,  and  which  is  a  most  important  element  in  their  Moral 
Education.1 

820.  The  faculty  of  Imagination  is  in  some  respects  opposed  in  its  cha- 
racter to  that  of  Reason ;  being  chiefly  concerned  about  fictitious  objects,  in- 
stead of  real  ones.  Still,  it  is  in  a  great  degree  an  exercise  of  the  same  powers, 
though  in  a  different  manner.  Thus  it  is  partly  concerned  in  framing  new  com- 
binations of  ideas  relating  to  external  objects,  and  is  thus  an  extended  exercise 
of  Conception ;  placing  us,  in  idea,  in  scenes,  circumstances,  and  relations  in 
which  actual  experience  never  found  us ;  and  thus  giving  rise  to  a  new  set  of 
objects  of  thought.  In  fact,  every  Conception  of  that  which  has  not  been  itself 
an  object  of  perception,  may,  strictly  speaking,  be  regarded  as  the  result  of  the 
exercise  of  Imagination.  Now  the  new  Conceptions  or  mental  creations  thus 
formed,  take  their  character,  in  great  degree,  from  the  Emotional  tendencies  of 
the  mind ;  so  that  the  previous  development  of  particular  feelings  and  affections 
will  influence,  not  merely  the  selection  of  the  objects,  but  the  mode  in  which 
they  are  thus  idealized.  In  the  higher  efforts  of  the  Imagination,  the  mind  is 
not  so  much  concerned  with  the  class  of  sensational  ideas,  as  with  those  of  the 
intellectual  character;  and  the  collocation,  analysis,  and  comparison  of  these, 
by  which  new  forms  and  combinations  are  suggested  to  the  mind,  involve  the 
exercise  of  the  same  powers  as  those  concerned  in  acts  of  Reasoning ;  but  they 
are  exercised  in  a  different  way.  Whilst  the  Imagination  thus  depends  upon 
the  Intellectual  powers  for  all  its  higher  operations,  the  understanding  may  be 
said  to  be  equally  indebted  to  the  imagination ;  for  the  ideal  combinations  which 

1  See  an  admirable  Discourse  on  "Unconscious  Influences,"  by  the  Rev.  Horace  Bush' 
nell,  of  Hartford  (N.  E.),  published  in  the  "Penny  Pulpit,"  No.  1199. 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  793 

are  the  results  of  the  action  of  the  latter,  do  not  merely  engage  the  attention 
of  the  Artist,  who  aims  to  develop  them  in  material  forms,  but  are  the  great 
sources  of  the  improvement  of  the  knowledge  and  happiness  possessed  by  our 
race — operating  alike  in  the  common  affairs  of  life,  by  suggesting  those  pic- 
tures of  the  future  which  are  ever  before  our  eyes,  and  are  our  animating  springs 
of  action ;  with  their  visions  of  enjoyment  never  perhaps  to  be  fully  realized, 
and  their  prospects  of  anticipated  evil  that  often  prove  to  be  an  exaggeration 
of  the  reality — prompting  the  investigations  of  Science,  that  are  gradually  un- 
folding the  sublime  plan  on  which  the  Universe  is  governed — and  leading  to  a 
continual  aspiration  after  those  highest  forms  of  Moral  and  Intellectual  beauty 
which  are  inseparably  connected  with  purity  and  love. 

821.  We  have  now,  in   the  last  place,  to  inquire  into  the  mode  in  which 
Volition  operates  in  determining  the  course  of  thought  and  the  regulation  of 
the  conduct ; — a  problem  of  extreme  difficulty,  the  entire  solution  of  which  may 
not  lie  within  the  limited  sphere  of  Man's  present  capacity.     The  chief  subject 
of  embarrassment  is  rather  the  nature  and  source  of  the  Will  itself,  than  the 
conditions  of  its  operation  ;  for  whilst  a  careful  analysis  of  our  own  conscious- 
ness throws  much  light  on  the  latter,  the  scientific  investigation  of  the  former 
tends  to  results  which  are  inconsistent  with  our  intuitive  conviction  of  freedom, 
as  well  as  with  our  scarcely  less  intuitive  notion  of  moral  responsibility.     Dis- 
missing the  former  question,  therefore,  as  one  which  requires  a  much  more 
labored  discussion  than   could  here   be  appropriately  bestowed  upon   it,  we 
may  apply  ourselves  to  the  consideration  of  the  mode  in  which  Volition  acts 
(1)  upon  the  Corporeal  organism,  and  (2)  upon  our  Psychical  nature. 

822.  It  is  a  fact  of  universal  experience,  that,  although  certain  states  of  Mind 
have  a  remarkable  influence  on  the  Organic  functions,  no  change  in  their  usual 
course  can  be  determined  by  the  direct  influence  of  the  Will.1     The  only  sensible 
effect  which  the  strongest  effort  of  Volition  can  produce  on  the  bodily  frame,  is 
the  excitation  of  muscular  contraction.     Now  if  we  examine  into  the  cause  of  a 
Volitional  movement,  we  find  it  to  lie,  as  in  other  instances,  in  a  certain  combi- 
nation of  material  conditions  with  dynamical  agency  (p.  3).     The  aggregate  of 
the  material  conditions  is  a  state  of  integrity  of  the  muscular  and  nervous  ap- 
paratus through  which  the  Will  operates;  the  dynamical  agency  is  the  effort 
which  we  are  conscious  of  putting  forth,  and  which  we  feel  to  be  the  power  by 
which  the  work  is  done,  the  degree  of  volitional  exertion  required  being  strictly 
proportional  to  the  amount  of  resistance  to  be  overcome,  and  being  followed  by 
a  corresponding  sense  of  fatigue,  which  is  the  indication  of  the  expenditure  of 
force.     As  already  pointed  out  (§  799),  it  is  an  essential  condition  of  every 
Volitional  action,  that  a  distinct  idea  should  exist  of  the  object  to  be  attained, 
and  that  there  should  be  also  a  belief  in  the  possibility  of  attaining  it  by  the 
means  employed ;  and  further,  the  amount  of  power  which  can  be  put  forth  on 
any  occasion,  is  dependent,  easterns  paribus,  upon  the  degree  in  which  the  at- 
tention is  concentrated  upon  the  effort,  and  the  mind  withdrawn  from  the  con- 
templation of  other  objects.     Hence  it  is  (we  have  seen)  that  Emotional  ex- 
citement may  either  intensify  or  paralyze  the  Volitional  power,  according  as  it 
determines  or  interferes  with  the  special  direction  of  the  mental  energy  to  the 
object  with  which  it  is  connected.     But  the  same  influence  is  capable  of  being 
exerted  by  the  simple  dominance  of  ideas,  in  certain  states  of  mind  in  which 
the  directing  power  of  the  Will  over  the  current  of  thought  is  altogether  sus- 
pended, without  the  destruction  of  the  capacity  for  voluntary  exertion  of  the 
nervo-muscular  apparatus.     Thus  the  Author  has  seen  a  man  remarkable  for 
the  poverty  of  his  muscular  development,  who  shrank  from  the  least  exertion  in 

1  "  Which  of  you,  by  taking  thought,  can  add  one  cubit  to  his  stature?"     "  Thou  canst 
'not  make  one  hair  white  or  black." 


794  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

his  ordinary  state,  lift  a  28-lb.  upon  his  little  finger  alone,  and  swing  it  round 
his  head  with  the  greatest  facility,  when  in  that  state  of  artificial  somnambulism 
termed  Hypnotism  by  Mr.  Braid  (§  827) ;  his  extraordinary  command  of  muscular 
power  in  this  condition  being  simply  due  to  the  complete  concentration  of  his 
mental  energy  upon  the  one  object,  and  to  the  dominance  of  the  idea  (with 
which  his  mind  was  possessed  by  the  confident  assurances  of  Mr.  Braid)  that  he 
could  attain  it  with  the  greatest  facility — that  idea  not  being  negatived  by  his 
ordinary  experience,  for  reasons  hereafter  to  be  stated  (§  824).  On  the  other 
hand,  the  same  individual  (whilst  in  the  hypnotic  state)  declared  himself  al- 
together unable  to  raise  a  handkerchief  from  the  table,  after  many  apparently 
strenuous  efforts;  his  mind  having  been  previously  possessed  by  the  assurance 
that  its  weight  was  too  great  for  him  to  move.1  In  that  curious  state  of  artifi- 
cial Reverie,  which  has  recently  attracted  much  attention  under  the  inappropri- 
ate name  of  "  Electro-Biology' '  (§  825),  precisely  the  same  phenomena  may  be 
observed;  the  subjects  of  it  being  prevented  from  performing  the  commonest 
voluntary  movements,  by  the  assurance  that  they  cannot  execute  them,  which 
assurance  takes  full  possession  of  their  minds,  in  virtue  of  their  .want  of  power 
to  bring  their  ordinary  experience  to  bear  upon  the  idea  thus  introduced;  whilst 
they  may  be  compelled  by  the  dominance  of  ideas,  introduced  in  like  manner 
by  external  suggestion,  to  perform  actions,  which,  if  not  physically  impossible 
to  them  in  their  ordinary  state,  they  could  not  be  induced  to  execute  by  any 
conceivable  motives. — These  facts  are  not  so  far  removed  from  our  ordinary 
experience  as  might  at  first  sight  appear.  For  it  must  be  within  the  know- 
ledge of  every  one,  that,  when  first  attempting  to  perform  some  new  kind  of 
action,  the  power  we  feel  capable  of  exerting  depends  in  great  measure  upon 
the  degree  of  our  assurance  of  success.  Of  this  we  have  a  good  example  in  the 
process  of  learning  to  swim  ;  which  is  greatly  facilitated,  as  Dr.  Franklin  pointed 
out,  by  our  first  taking  means  to  satisfy  ourselves  of  the  buoyancy  of  our  bodies 
in  the  water,  by  attempting  to  pick  up  an  object  from  the  bottom.  And  every 
one  is  aware  of  the  assistance  derived  from  the  encouragement  of  others,  when 
we  are  ourselves  doubtful  of  our  powers ;  and  of  the  detrimental  influence  of 
discouragement  or  suggested  doubt,  even  when  we  previously  felt  a  considerable 
confidence  of  success.2  These  familiar  facts  show  us,  therefore,  that  the  pheno- 

1  The  Author  has  every  reason  to  believe  that  the  personal  character  of  this  indivi- 
dual placed  him  above  the  suspicion  of  deceit ;  and  it  is  obvious  that,  if  he  had  practised 
the  first  of  the  above  performances  (which  very  few,  even  of  the  strongest  men,  could 
accomplish  without  practice),  the  effect  would  have  been  visible  in  his  muscular  develop- 
ment.    Of  course,  there  was  not  an  equal  proof  of  the  absence  of  deception  in  the  second 
case  as  in  the  first;  but  if  the  reality  of  the  first,  and  the  validity  of  the  explanation 
above  given,  be  admitted,  there  need  be  no  difficulty  in  the  reception  of  the  second, 
since  it  is  only  another  manifestation  of  the  same  mental  condition. 

2  The  Author  well  remembers,  several  years  ago,  being  among  those  who  tested  the 
validity  of  the  statement  put  forth  in  Sir  D.  Brewster's  "Natural  Magic,"  that  four  per- 
sons can  lift  a  full-sized  individual  from  the  ground,  high  into  the  air,  with  the  greatest 
facility,  if  they  all  take  in  a  full  breath  previously  to  the  effort,  the  person  lifted  doing 
the  same.     He  could  readily  understand,  upon  physiological  principles,  that  a  full  inspi- 
ration on  the  part  of  the  lifters  would  have  a  certain  degree  of  efficacy  in  augmenting 
their  nervo-muscular  power ;  but  he  could  not  perceive  how  the  performance  of  the  same 
act  by  the  person  lifted  could  have  any  appreciable  effect;  and  while  many  of  his  acquaint- 
ances assured  him  that,  when   all  the  conditions    were  duly  observed,  the  body  went 

,  up  "like  a  feather,"  and  that  they  felt  satisfied  of  being  able  to  support  it  upon  the 
points  of  their  fingers,  he  found  his  own  experience  quits  different ;  and  came  to  the  con- 
clusion, after  much  observation,  that  the  facility  afforded  by  this  method  entirely  de- 
pended upon  the  degree  in  which  it  fulfilled  the  above-mentioned  conditions,  namely,  the 
fixation  of  the  attention  upon  the  effort,  and  the  conviction  of'  the  success  of  the  method. 
Whenever  the  attention  was  distracted  and  confidence  weakened  by  skepticism  as  to  the 
result,  the  promised  assistance  was  not  experienced. — The  Author  may  also  mention,  as  a 
very  characteristic  illustration  of  the  same  principles,  the  following  little  circumstance 


THE   CEREBRUM,    AND   ITS    FUNCTIONS.  795 

mena  just  described  as  occurring  in  abnormal  states  are  in  no  respect  contrary 
to  our  knowledge  of  the  conditions  under  which  the  Will  operates  in  producing 
muscular  movement ;  but  afford,  when  rightly  interpreted,  a  strong  confirmation 
of  the  statements  already  made  respecting  the  nature  of  those  conditions. 

823.  The  Will  is  exerted,  however,  not  merely  in  determining  the  actions 
of  the  body,  but  also  in  regulating  the  operations  of  the  Mind ;  and  here  again 
we  find  that  its  action  is  limited  by  certain  conditions,  the  knowledge  of  which 
is  of  great  importance.  It  may  be  said,  generally,  that  we  have  no  direct  power 
of  calling  before  our  consciousness,  by  a  volitional  effort,  ideas  which  are  not 
already  present  there ;  thus,  in  the  act  of  Recollection,  we  can  do  no  more  than  fix 
our  minds  upon  those  ideas  which  seem  most  likely  to  recall,  by  an  act  of  sugges- 
tion, the  one  which  we  desiderate  (§  813).  But  what  we  do  possess,  is  the  power 
of  excluding  some  ideas,  and  of  bringing  others  prominently  before  our  mental 
vision ;  and  this  by  the  power  of  Voluntary  Attention,  which  is  the  chief  if  not 
the  sole  means  by  which  the  sequence  of  our  thoughts  is  directed  by  the  Will. 
It  has  been  already  pointed  out  that  the  Attention  may  be  involuntarily  fixed 
upon  certain  subjects  of  consciousness,  through  the  attraction  they  exert  upon 
the  individual  mind,  in  virtue  either  of  its  original  constitution  or  of  its  ac- 
quired habitudes ;  it  being  this  attraction  which  determines  the  automatic  action 
of  our  faculties  (§  811).  When  most  strongly  exerted,  it  causes  the  conscious- 
ness to  be  so  completely  engrossed  by  one  train  of  ideas,  that  the  mind  is,  for 
the  time,  incapable  of  any  other  ideational  change  :  sensory  impressions,  if  felt 
not  being  perceived  ;  and,  where  the  consciousness  is  most  completely  concen- 
trated upon  the  internal  operations,  the  individual  being  as  insensible  to  external 
impressions  as  if  he  were  in  a  profound  sleep.  But  these  automatic  tendencies 
of  the  mind  may  be  to  a  certain  extent  antagonized  by  the  Will,  which  keeps 
them  in  check  (just  as  it  restrains  many  of  the  automatic  impulses  to  bodily 
movement)  by  the  special  power  which  it  exerts  over  the  Attention.  This  it 
can  detach  from  subjects  which  have  at  the  time  the  greatest  attractive- 
ness to  it,  and  can  forcibly  direct  it  to  others  from  which  the  former  would 
otherwise  divert  it.  And  in  its  most  complete  and  powerful  exercise  (which  is  not 
within  the  capacity  of  every  one),  it  can  so  completely  limit  the  mind  to  one 
train  of  thought,  that  the  state  of  Abstraction  induced  by  the  Will  may  be  as 
complete  as  that  which  in  some  individuals  is  of  spontaneous  occurrence.  In 
proportion  as  we  are  able  thus  to  concentrate  our  attention  on  the  subject  pro- 
per to  the  time,  and  to  exclude  all  distracting  considerations  whilst  pursuing 
the  trains  of  thought  which  the  contemplation  of  it  suggests,  will  be  our  power 
of  advantageously  employing  our  Intellectual  Faculties  in  the  acquirement  of 
knowledge  and  in  the  pursuit  of  truth;  and  all  men  who  have  been  distin- 
guished by  their  intellectual  achievements  have  possessed  this  faculty  in  a 
considerable  degree.  It  is  one  which  is  "eminently  capable  of  cultivation 
by  steady  intention  of  mind  and  habitual  exercise  •"  and  the  more  frequently  it 
is  put  in  practice,  the  easier  the  exercise  becomes.  In  fact,  when  a  man  has 
once  brought  his  Intellectual  faculties  under  the  mastery  of  his  Will,  to  such  an 
extent  as  to  induce  the  state  of  Abstraction  whenever  he  pleases,  this  state  be- 
comes (as  it  were)  "secondarily  automatic;"  and  the  fixed  direction  of  the 
thoughts,  which  at  first  required  a  constant  volitional  effort  for  its  maintenance, 
comes  to  be  continued  without  any  consciousness  of  exertion,  so  long  as  the 
Will  may  permit. — We  have,  in  our  own  consciousness  of  effort,  and  in  our 

communicated  to  him  by  a  friend.  This  gentleman  relates  that  having  been  accustomed 
in  his  boyhood  to  play  at  bagatelle  with  other  juniors  of  his  family,  the  party  was  occa- 
sionally joined  by  a  relative  who  was  noted  for  her  success  at  the  game,  and  who  was 
consequently  much  dreaded  as  an  opponent;  and  that,  on  one  occasion,  when  she  was 
about  to  take  her  turn  against  him,  he  roguishly  exclaimed,  "Now,  aunty,  you  will  not 
be  able  to  make  a  hit;"  the  eifect  of  which  suggestion  was  that  she  missed  every  stroke 
— and  not  only  at  that  turn,  but  through  the  remainder  of  the  evening. 


796  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

experience  of  subsequent  fatigue,  a  very  strong  indication  that  the  power  which 
thus  controls  and  directs  the  current  of  thought,  is  of  the  same  kind  with  that 
which  calls  forth  Volitional  movements  of  the  body,  though  exerted  in  a  different 
mode.  And  just  as  the  strongest  exertion  of  Will  is  required  to  produce  or 
sustain  Muscular  contraction,  when  the  sense  of  muscular  fatigue  is  already 
strongly  experienced,  or  when  we  are  antagonizing  a  powerful  automatic  impulse, 
so,  in  the  determination  of  Mental  effort  in  a  particular  direction,  we  find  our- 
selves necessitated  to  make  the  greatest  Volitional  effort  when  we  are  already 
laboring  under  the  sense  of  cerebral  fatigue,  or  when  the  attention  is  powerfully 
solicited  by  some  other  attractive  object.  And  it  is  after  any  such  contest  with 
our  natural  tendencies,  that  we  experience  the  greatest  degree  of  exhaustion  j 
the  merely  automatic  action  of  the  Mind,  which  is  attended  with  no  effort,  being 
followed  by  comparatively  little  fatigue.1 

824.  But  this  determining  power  of  Volition  is  employed,  in  however  slight 
a  degree,  whenever  the  succession  of  thought  is  not  perfectly  spontaneous  ;a 
whenever,  in  fact,  we  wish  our  consciousness  to  take  a  particular  direction,  even 
for  the  apprehension  of  ideas  most  familiar  to  our  minds.  Of  this  we  derive  the 
best  evidence  from  those  curious  states  in  which  the  directing  power  of  the  Will 
is  entirely  suspended,  whilst  yet  the  mind  remains  freely  open  to  external  im- 
pressions ;  a  .condition  which  shows  us  what  we  should  be,  if  we  really  were  what 
some  writers  assure  us  that  we  actually  are,  mere  thinking  automata,  puppets 
moved  in  any  direction  by  the  pulling  of  suggesting  strings  (§  802,  note).  This 
condition  presents  itself  spontaneously  in  some  individuals,  and  may  be  induced 
in  others ;  and  it  is  not  a  little  remarkable  that  it  may  occur  as  a  modification 
both  of  the  waking  and  the  sleeping  states.  Of  the  former  we  have  an  example 

1  The  author  is  satisfied,  from  his  own  experience,  that  a  most  valuable  indication  may 
be  hence  drawn,  in  regard  to  the  regulation  of  the  habits  of  Intellectual  labor.     To  indivi- 
duals of  ordinary  mental  activity,  who  have  been  trained  in  the  habit  of  methodical  and 
connected  thinking,  a  very  considerable  amount  of  work  is  quite  natural ;  and  when  such 
persons  are  in  good  bodily  health,  and  the  subject  of  their  labor  is  congenial  to  them — 
especially  if  it  be  one  that  has  been  chosen  by  themselves  because  it  furnishes  a  centre  of 
attraction  around  which  their  thoughts  spontaneously  tend  to  range  themselves — their 
intellectual  operations  require  but  little  of  the  controlling  or  directing  power  of  the  Will, 
and  may  be  continued  for  long  periods  together  without  fatigue.     But  from  the  moment 
when  an  indisposition  is  experienced  to  keep  the  attention  fixed  upon  the  subject,  and  the 
thoughts  wander  from  it  unless  coerced  by  the  Will,  the  mental  activity  loses  its  sponta- 
neous or  automatic  character ;  and  more  exertion  is  required  to  maintain  it  volitionally 
during  a  brief  period,  and  more  fatigue  is  subsequently  experienced  from  such  an  effort, 
than  would  be  involved  in  the  continuance  of  an  automatic  operation  through  a  period 
many  times  as  long.     Hence  he  has  found  it  practically  the  greatest  economy  of  mental 
labor,  to  work  vigorously  when  he  feels  disposed  to  do  so,  and  to  refrain  from  exertion,  so 
far  as  possible,  when  it  is  felt  to  be  an  exertion. — Of  course  this  rule  is  not  applicable  to  all 
individuals,  for  there  are  some  who  would  pass  their  whole  time  in  listless  inactivity  if  not 
actually  spurred  on  by  the  feeling  of  necessity ;  but  it  holds  good  for  those  who  are  sufficiently 
attracted  by  objects  of  interest  before  them,  or  who  have  in  their  worldly  circumstances  a 
sufficiently  strong  motive  to  exertion,  to  make  them  feel  that  they  must  work,  the  question 
with  them  being  how  they  can  attain  their  desired  results  with  the  least  expenditure  of 
mental  labor. 

2  It  is  hoped  that  the  reader  will  have  been  made  sufficiently  aware,  by  the  preceding 
explanations,  that  by  the  terms  "spontaneous"  or  "automatic"  succession  of  thought,  it 
is  intended  to  designate  that  sequence  of  states  of  consciousness,  in  which  every  one  is  the 
immediate  resultant  of  that  which  preceded  it,  whether  that  were  ideational  or  sensational. 
Thus  the  current  of  thought  is  alike  "  spontaneous,"  when  it  flows  onwards  in  one  continuous 
channel,  being  directed  by  a  single  dominant  idea  which  absorbs  the  whole  attention ;  and 
when  the  mind  is  freely  accessible  to  external  impressions,  and  may  be  entirely  guided  by 
them.     The  phenomena  of  Reverie,  Abstraction,  and  Somnambulism  (as  will  be  presently 
seen)  afford  illustrations  of  both  these  states ;  which,  though  apparently  opposite  in  their 
nature,  are  really  characterized  by  the  same  essential  feature,  namely,  the  absence  of  the 
directing  power  of  the  Will. 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  797 

in  ordinary  Reverie,  a  state  to  which  some  persons  are  peculiarly  prone ;  the 
characteristic  of  which  is,  that  whilst,  as  in  Dreaming,  the  succession  of  thought 
is  entirely  automatic,  it  is  in  no  small  degree  influenced  by  external  impressions, 
especially  such  as  arise  from  the  various  phenomena  of  Nature.  It  is  in  minds 
in  which  the  emotional  and  imaginative  elements  predominate,  that  we  usually 
find  the  greatest  tendency  to  reverie ;  and  the  sequence  of  thought,  if  subse- 
quently analyzed,  will  be  found  to  have  been  chiefly  determined  by  these  tend- 
encies. Now  this  sequence  may  conduct  us  to  notions  altogether  inconsistent 
with  our  most  familiar  experience ;  and  yet  we  accept  them  as  realities,  not- 
withstanding this  incongruity,  because  the  ideas  to  which  they  are  opposed  are 
not  present  to  our  minds  at  the  time,  and  the  dormant  state  of  our  Will  prevents 
us  from  making  the  slightest  effort  to  bring  them  before  the  consciousness.  The 
state  of  Abstraction,  or  "  absence  of  mind/'  is  essentially  the  same  with  that  of 
reverie ;  the  chief  difference  being,  that  in  true  Abstraction  the  mind  is  at  work 
ratiocinatively,  a  certain  train  of  thought  being  followed  out  by  the  intellectual 
operations  to  its  logical  conclusion ;  it  being  the  Philosopher  who  is  most  prone 
to  abstraction,  as  the  Poet  is  to  reverie.  Now  it  is  one  of  the  most  curious 
phenomena  of  this  state,  that  external  impressions,  if  received  by  the  conscious- 
ness at  all,  are  very  often  wrongly  perceived,  being  interpreted  in  accordance 
with  the  ideas  which  happen  to  be  dominant  in  the  mind  at  the  time,  instead  of 
giving  rise  to  those  new  ideas  which  ordinarily  connect  themselves  with  them, 
in  virtue  of  the  individual's  habitual  experience.  The  records  of  "  absence  of 
mind"  are  full  of  amusing  instances  of  such  misinterpretation.  Nothing  seems 
too  strange  for  the  individual  to  believe,  nothing  too  absurd  for  him  to  do  under 
the  influence  of  that  belief.  Thus  of  Dr.  Robert  Hamilton,  a  well-known  Pro- 
fessor at  Aberdeen,  who  was  the  author  of  many  productions  distinguished  for 
their  profound  and  accurate  science,  their  beautiful  arrangement,  and  their  clear 
expression,  we  are  informed  that,  u  In  public,  the  man  was  a  shadow;  pulled 
oft'  his  hat  to  his  own  wife  in  the  streets,  and  apologized  for  not  having  the 
pleasure  of  her  acquaintance ;  went  to  his  classes  in  the  college  on  the  dark 
mornings  with  one  of  her  white  stockings  on  the  one  leg,  and  one  of  his  own 
black  ones  on  the  other ;  often  spent  the  whole  time  of  the  meeting  in  moving 
from  the  table  the  hats  of  the  students,  which  they  as  constantly  returned ; 
sometimes  invited  them  to  call  on  him,  and  then  fined  them  for  coming  to  insult 
him.  He  would  run  against  a  cow  in  the  road,  turn  round,  beg  her  pardon, 
call  her  l  Madam/  and  hope  she  was  not  hurt.  At  other  times,  he  would  run 
against  posts,  and  chide  them  for  not  getting  out  of  his  way/'1 

825.  A  state  may  be  artificially  induced  in  many  individuals,  by  a  continued 
fixed  gaze  at  an  object  at  a  moderate  distance,  which  is  the  same  as  that  of 
Reverie  and  Abstraction  in  regard  to  the  complete  suspension  of  the  directing 
power  of  the  Will  over  the  current  of  thought,  but  which  differs  from  these  in 
the  readiness  with  which  the  mind  may  be  possessed  with  ideas  suggested  to  it 
through  the  medium  of  language.  This  state  has  been  commonly  known  by 
the  name  Electro-Biological,  from  the  mode  in  which  its  induction  was  originally 
practised  ;2  but  it  is  now  more  frequently  designated  by  the  very  inappropriate 

1  See  "New  Monthly  Magazine,"  vol.  xxviii.  p.  510. — The  Author  has  heard  from  an  old 
pupil  of  Dr.  Hamilton  an  anecdote  so  singularly  illustrative  of  this  peculiar  condition,  that 
he  cannot  refrain  from  here  introducing  it.     The  Professor,  walking  one  day  along  the 
High  Street  with  the  front  of  his  breeches  open  (no  very  unusual  occurrence  with  him), 
chanced  to  encounter  a  woman  in  a  white  apron ;  and  apparently  mistaking  this  apron  for 
his  own  shirt,  he  laid  hold  of  it,  and  began  to  push  it  into  the  situation  which  his  shirt 
should  occupy ! 

2  The  "Electro-Biologists,"  as  they  term  themselves,  at  first  maintained  that  a  wonderful 
virtue  resided  in  the  little  disk  of  copper  with  a  zinc  centre,  to  which  they  directed  the 
gaze  of  their  "  subjects."     It  is  now  universally  admitted,  however,  that  any  object  which 


798  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

term  Biological.  The  subject  of  it  may  be  truly  characterized  as  a  thinking 
automaton,  the  whole  course  of  whose  ideas  may  be  determined  by  suggestions 
operating  from  without;  and  his  mind,  having  in  itself  no  power  of  altering  the 
course  of  these  in  even  the  slightest  degree,  is  cut  off  from  all  recourse  to  pre- 
vious experience  for  the  examination  of  their  correctness  or  the  determination 
of  their  fallacy.  The  senses  of  the  biologized  subject  are  freely  accessible  to 
external  impressions ;  but,  as  in  the  case  of  the  "  absent"  man,  his  perception 
of  these  is  governed  by  the  ideas  which  may  be  dominant  in  his  mind  at  the 
time ;  and  he  may  be  consequently  led  to  any  kind  of  absurd  misinterpretation 
of  them.  Yet  his  state  of  mind  is  not  so  far  removed  from  his  ordinary  condi- 
tion as  to  prevent  his  usual  habits  of  thought  and  feeling  from  displaying  them- 
selves ;  and  he  has  in  most  cases  a  perfect  recollection  of  what  has  taken  place, 
when  he  returns  to  his  usual  condition  of  mental  activity,  though  sometimes  the 
recollection  does  not  extend  to  particulars.  All  the  phenomena  of  the  "  biolo- 
gized" state,  when  attentively  examined,  will  be  found  to  consist  in  the  occupa- 
tion of  the  mind  by  the  ideas  which  have  been  suggested  to  it,  and  in  the  in- 
fluence which  these  ideas  exert  upon  the  actions  of  the  body.  Thus  the  operator 
asserts  that  the  "  subject"  cannot  rise  from  his  chair,  or  open  his  eyes,  or 
continue  to  hold  a  stick ;  and  the  "  subject"  thereby  becomes  so  completely 
possessed  with  the  fixed  belief  of  the  impossibility  of  the  act,  that  he  is  incapa- 
citated from  executing  it,  not  because  his  will  is  controlled  by  that  of  another, 
but  because  his  will  is  in  abeyance,  and  his  muscles  are  entirely  under  the 
guidance  of  the  conviction  which  for  the  time  possesses  his  mind.  So,  again, 
when  he  is  made  to  drink  a  glass  of  water,  and  is  assured  that  it  is  coffee,  or 
wine,  or  milk,  that  assurance,  delivered  in  a  decided  tone,  makes  a  stronger 
impression  on  his  mind  than  that  which  he  receives  through  his  taste,  smell,  or 
sight;  and  not  being  able  to  judge  and  compare,  he  yields  himself  up  to  the 
"  dominant  idea."1  Here,  again,  we  perceive  that  it  is  not  really  the  will  of 
the  operator  which  controls  the  sensations  of  the  subject;  but  the  suggestion  of 
the  operator  which  excites  a  corresponding  idea,  the  falsity  of  which  is  not 
corrected,  simply  because  the  mind  of  the  subject,  being  completely  engrossed 
by  it,  cannot  apprehend  the  truth  less  forcibly  impressed  on  it  through  his  own 
senses.  The  same  general  statement  applies  to  what  has  been  designated  as 
"control  over  the  memory."  The  subject  is  assured  that  he  cannot  remember 
the  most  familiar  thing,  his  own  name  for  example ;  and  he  is  prevented  from 
doing  so,  not  by  the  will  of  the  operator,  but  by  the  conviction  of  the  impossi- 
bility of  the  mental  act,  which  engrosses  his  own  mind,  and  by  the  want  of  that 

serves  as  a  point  cTappui  for  the  fixed  gaze,  is  equally  efficacious. — The  Author  has  no 
hesitation  in  avowing  his  belief  in  the  reality  of  the  phenomena,  which  are  described  as 
occurring  in  this  state;  these  having  been  presented  to  himself  and  to  other  scientific 
inquirers,  by  numerous  individuals,  on  whose  honesty  and  freedom  from  all  disposition  to 
deceive  themselves  or  others,  implicit  reliance  could  be  placed.  All  public  exhibitions,  the 
performers  in  which  are  of  questionable  character,  are  of  course  open  to  the  obvious  fallacy 
of  intentional  deceit.  With  regard  to  the  interpretation  of  these  phenomena,  however,  he 
entirely  dissents  from  the  statements  commonly  made,  to  the  effect  that  the  Will  of  the 
"  biologized"  subject  is  entirely  under  the  control  of  that  of  the  operator ;  since  he  regards 
the  latter  as  having  no  other  influence  over  the  former  than  through  the  suggestions  which 
his  language  and  manner  convey. 

1  It  is  very  curious  to  observe,  in  some  instances,  the  perplexity  arising  from  the  contra- 
riety between  the  opposing  sensory  impressions.  The  mind  seems  unable  to  reconcile  this 
contrariety,  and  yields  itself  up  to  the  impression  which  is  most  strongly  felt.  Sometimes 
it  is  convinced  by  the  repeated  assurances  of  the  operator,  so  long  as  the  taste  alone  is 
opposed  to  them,  but  attaches  a  superior  importance  to  the  indications  of  sight;  in  other 
individuals,  again,  the  indications  of  sight  maybe  put  aside,  and  yet  the  "  subject"  cannot 
be  made  to  believe  what  is  in  opposition  to  his  sense  of  taste.  There  are  some  individuals 
who  can  never  be  thus  played  upon,  notwithstanding  that  their  muscular  movements  and 
their  purely  mental  conceptions  are  completely  amenable  to  this  kind  of  direction. 


THE   CEREBRUM,   AND   ITS   FUNCTIONS.  799 

voluntary  control  over  the  direction  of  his  thoughts  which  alone  can  enable 
him  to  recall  the  desiderated  impression.  And  the  abolition  of  the  sense  of 
personal  identity — Mr.  A.  believing  himself  to  be  Mrs.  B.,  or  Mrs.  C.  believing 
herself  to  be  Mr.  D.,  and  acting  in  conformity  with  that  belief — is  induced  in 
the  same  mode;  the  assurance  being  continually  repeated,  until  it  has  taken  full 
possession  of  the  mind  of  the  "  subject,"  who  cannot  so  direct  his  thoughts  as 
to  bring  his  familiar  experience  to  antagonize  and  dispel  the  illusive  idea  thus 
forced  upon  him.  The  phenomena  presented  by  different  a  biologized  subjects" 
are  by  no  means  the  same;  for  in  some  individuals  it  is  the  relation  of  the  mind 
to  bodily  action  which  is  most  remarkably  affected,  in  others  it  is  the  relation  of 
the  perceptive  consciousness  to  sensations,  and  in  others  (especially  those  who 
are  naturally  of  an  imaginative  and  excitable  disposition)  it  is  the  course  of 
thought  and  of  emotion  which  is  most  completely  under  external  guidance.  It 
is  frequently  to  be  observed,  moreover,  that  some  capability  of  volitional  effort 
still  remains,  so  that  the  "  subject"  endeavors  to  resist  the  commands  of  the 
operator ;  but  this  may  usually  be  subdued  by  the  emphatic  reiteration  of  the 
assurance  "  You  must  do  this/'  or  "  You  cannot  do  that,"  which,  when  it  takes 
complete  possession  of  the  mind  of  the  subject,  reduces  the  will  to  a  state  of 
entire  powerlessness.1 

826.  It  is  obvious  that,  if  the  account  here  given  of  the  condition  of  the 
Mind  and  of  the  mode  of  its  operation  on  the  Body,  in  the  state  of  natural 
and  artificial  Reverie  and  Abstraction,  be  correct,  all  the  actions  performed  in 
these  states  must  be  regarded  as  essentially  automatic  in  their  nature;  the 
course  of  thought  being  entirely  determined  by  the  associations  previously  formed, 
and  all  the  bodily  movements  being  the  direct  manifestations  of  the  ideas  which 
possess  the  mind  at  the  time,  just  as  the  ordinary  movements  of  " expression" 
are  of  its  emotions.  And  it  is,  therefore,  in  these  remarkable  phases  of  psychical 
existence,  that  we  have  the  clearest  manifestation  of  the  power  which  Cerebral 
changes  possess,  to  produce  muscular  movement  independently  either  of  Voli- 
tion or  of  Emotion ;  an  action  which  may  be  distinguished  as  ideo-motor,  since 
it  only  takes  place  when  these  changes  are  of  a  kind  to  awaken  the  ideational 
consciousness;  and  which  is  a  true  "reflex"  action  of  the  Cerebrum.  The 
same  designation  may  be  fairly  applied,  also,  to  all  those  actions  performed  by 
us  in  our  ordinary  waking  state,  which  are  rather  the  automatic  expressions  of 
the  ideas  which  are  dominant  in  our  minds  at  the  time,  than  prompted  by  dis- 
tinct volitional  effort  (§  817).  Of  this  kind,  the  act  of  expressing  the  thoughts 
in  language,  whether  by  speech  or  writing,  may  be  considered  as  a  good  ex- 
ample; for  the  attention  may  be  so  completely  given  up  to  the  choice  of  words 
and  to  the  composition  of  the  sentences,  that  the  movements  by  which  these 
words  are  uttered  by  the  voice  or  traced  on  paper  no  more  partake  of  the  truly 
volitional  character,  than  do  those  of  our  limbs  when  we  walk  through  the 
streets  in  a  state  of  Abstraction.  And  it  is  a  curious  evidence  of  the  influence 
of  Ideas,  rather  than  of  the  agency  of  the  Will,  in  producing  them,  that,  as  our 
conceptions  are  a  little  in  advance  of  our  speech  or  writing,  it  occasionally 

1  It  is  worthy  of  particular  notice  in  this  connection,  that  this  want,  not  really  of  power 
to  move,  but  of  belief  in  the  possession  of  the  power,  is  a  frequent  characteristic  of  that 
state  of  the  nervous  system  which  is  commonly  designated  as  "  Hysterical;"  and  that  here, 
also,  the  most  efficacious  treatment  consists  in  the  encouragement  of  volitional  efforts  on 
the  part  of  the  patient  to  put  the  paralyzed  limbs  in  action,  and  in  the  repetition  of  assur- 
ances that  she  will  recover  the  use  of  them,  if  she  only  take  the  appropriate  means.  The 
expectation  of  recovery  excited  in  other  ways  produces  the  same  eifect ;  and  thus  it  has 
been  that  many  pseudo-miracles  have  been  wrought  on  this  class  of  patients  by  religious 
enthusiasts,  and  that  many  wonderful  cures  have  been  effected  by  the  supposed  influence 
of  Mesmerism.  All  that  is  wanted  is  that  state  of  confident  anticipation  which  is  commonly 
designated  as  Faith. 


800  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

happens  that  we  mispronounce  or  misspell  a  word,  by  introducing  into  it  a 
portion  of  some  other  whose  turn  is  shortly  to  come,  its  place  in  the  sentence 
which  is  in  process  of  formation  being  a  little  further  on;  or  it  may  be  that 
the  whole  of  the  anticipated  word  is  substituted  for  the  one  which  ought  to 
have  been  expressed.  Now  it  is  obvious  that  there  could  be  neither  any  con- 
sciously formed  intention  of  breaking  the  regular  sequence,  nor  any  volitional 
effort  to  do  so;  and  the  result  is  evidently  due  to  the  superior  vividness  with 
which  the  idea  of  the  anticipated  word  is  present  to  the  mind,  as  compared  with 
that  of  the  word  which  the  course  of  construction  requires.  It  is  the  dominant 
idea,  then,  which  determines  the  movement,  the  Will  simply  permitting  it ; 
and  the  more  completely  the  Volitional  power  is  directed  to  other  objects,  the 
more  completely  automatic  are  the  actions  of  this  class.  They  may,  indeed, 
come  to  be  performed  even  without  the  consciousness,  or  at  least  without  the 
remembered  consciousness,  of  the  agent ;  as  we  see  in  the  case  of  those  who 
have  the  habit  of  "  thinking  aloud,"  and  who  are  subsequently  quite  surprised 
on  learning  what  they  have  uttered.  The  one-sided  conversation  of  some 
persons,  who  are  far  more  attentive  to  their  own  trains  of  thought,  than  they 
are  to  what  may  be  expressed  by  others,  and  who  are  allowed  to  proceed  with 
little  or  no  interruption,  is  often  a  sort  of  "  thinking  aloud."1 — All  that  is 
here  stated  is  in  perfect  accordance  with  the  general  principle  already  laid  down 
(§  683),  that  in  proportion  as  the  higher  channels  of  activity  are  obstructed, 
will  the  excitation  of  nerve-force  manifest  itself  through  the  lower.  For, 
whilst  the  ordinary  sequence  is  for  external  impressions  to  excite  sensations, 
for  sensations  to  excite  ideas,  and  for  ideas  (after  becoming  the  subject  of 
reasoning  processes  of  greater  or  less  complexity)  to  issue  in  volitional  deter- 
minations, the  direct  action  of  ideational  changes  in  the  Cerebrum  on  the 
motor  system,  when  either  the  Will  is  in  abeyance  or  is  entirely  directed  to 
mental  operations,  seems  quite  as  natural  as  the  immediate  reaction  of  sensa- 
tional changes  through  the  Sensory  ganglia,  or  of  impressional  changes  through 
the  Spinal  Cord. 

827.  The  phenomena  of  Somnambulism  are  no  less  important  in  a  scientific 
point  of  view,  when  they  are  regarded  under  the  same  aspect.  They  differ  from 
those  already  described,  in  that  they  occur  in  a  state  of  consciousness  so  far  distinct 
from  the  ordinary  waking  condition,  as  not  to  be  connected  with  it  by  the  ordi- 
nary link  of  Memory;  and  although  the  course  of  thought  in  Somnambulism 
usually  manifests  the  directing  influence  of  previous  habits,  and  the  knowledge 
of  persons  and  things  possessed  during  the  waking  state  may  be  readily  brought 
before  the  mind,  yet  nothing  which  occurs  during  the  state  of  Somnambulism 
is  ever  retraced  spontaneously,  or  can  be  brought  back  by  an  act  of  recollection. 
Impressions  upon  the  nervous  system,  however,  are  sometimes  left  by  strong 
emotional  excitement,  which  give  rise  to  subsequent  feelings  of  discomfort,  of 
whose  origin  the  individual  is  entirely  unconscious.3  The  phenomena  of  Som- 
nambulism are  so  various,  that  it  is  difficult  to  give  any  general  definition  that 
shall  include  the  whole ;  but  it  is  a  condition  which  is  common  to  all  forms  of 
this  state,  that  the  controlling  power  of  the  Will  over  the  current  of  thought 
is  entirely  suspended,  and  that  all  the  actions  are  directly  prompted  by  the  ideas 
which  possess  the  mind ;  and  the  differences  chiefly  arise  out  of  the  mode  in 
which  the  succession  of  ideas  is  directed,  this  being  in  some  cases  a  coherent 
sequence  through  the  whole  of  which  some  one  dominant  impression  may  be 
traced,  whilst  in  other  instances  it  is  more  or  less  completely  determinable  by  ex- 

1  This  was  pre-eminently  the  case  with  Coleridge,  whose  peculiar  habits  have  been 
already  noticed,  $  817,  note. 

2  See  a  very  curious  example  of  this  kind,  which  fell  under  the  author's  own  observa- 
tion, narrated  in  the  Article  "Sleep,"  in  the  "Cyclop,  of  Anat.  and  Phys.,"  vol.  iv. 
p.  693. 


THE  CEREBRUM,   AND   ITS   FUNCTIONS.  801 

ternal  suggestions. — The  first  of  these  phases,  which  is  nearly  akin  to  the  state 
of  Abstraction,  is  frequently  seen  in  natural  Somnambulism ;  in  which  a  train 
of  reasoning  is  often  carried  out  with  remarkable  clearness  and  correctness,  and 
its  results  expressed  in  appropriate  language,  or  otherwise  acted  on.     Thus,  a 
mathematician  may  work  out  a  difficult  problem,  an  orator  make  a  speech  ap- 
propriate to  the  occasion  on  which  he  supposes  himself  to  be  called  up,  or  an 
author  may  compose  and  commit  to  writing  poetry  or  prose,  upon  the   subject 
which  occupies  his  thoughts.     But  it  is  a  frequent  defect  of  the  intellectual 
operations  carried  on  in  this  condition,  that,  through  the  complete  absorption  of 
the  attention  by  one  set  of  considerations,  no  account  is  taken  of  others  which 
ought  to  modify  the  conclusion ;  and  this,  although  it  may  be  palpably  incon- 
sistent with  the  teachings  of  ordinary  experience,  is  not  felt  to  be  so,  unless  the 
latter  should  happen  to  present  themselves  unbidden  to  the  thoughts. — The  se- 
cond of  the  phases  above  mentioned,  which  is  especially  seen  in  the  artificial 
Somnambulism  induced  by  the   (so  called)   Mesmeric  process,  or  by  the  fixed 
gaze  at  a  near  object  (as  practised  by  Mr.  Braid  under  the  name  of  Hypnotism), 
is  essentially  the  same  as  that  of  the  "  biological"  condition,  save  in  the  differ- 
ent relation  which  they  respectively  bear  to  the  waking  state ;  for  there  is  the 
same  readiness  to  receive  new  impressions  through  the  senses  (the  visual  sense, 
however,  being  generally  in  abeyance),  and  the  same  want  of  persistence  in 
any  one  train  of  ideas,  the  direction  of  the  thoughts  being  entirely  determined 
by  the  suggestions  which  are  introduced  from  without.     In  either  of  these  ex- 
treme forms  of  Somnambulism,  and  in  the  numerous  intermediate  phases  which 
connect  the  two,  the  consciousness  seems  entirely  given  up  to  the  one  impression 
which  is  operating  upon  it  at  the  time ;  so  that  whilst  the  attention  is  exclu- 
sively directed  upon  any  object,  whether  actually  perceived  through  the  senses, 
or  brought  suggestively  before  the  mind  by  previous  ideas,  nothing  else  is  felt. 
Thus  there  may  be  complete  insensibility  to  bodily  pain,  the  somnambulist's 
whole  attention  being  given  to  what  is  passing  in  his  mind ;  yet  in  an  instant, 
by  directing  the  attention  to  the  organs  of  sense,  the  anaesthesia  may  be  replaced 
by  ordinary  sensibility ;  or,  by  the  fixation  of  the  attention  on  any  one  class  of 
sensations,  these  shall  be  perceived  with  most  extraordinary  acuteness,  whilst 
there  may  be  a  state  of  complete  insensibility  as  regards  the  rest.     So,  again, 
when  the  attention  of  the  somnambulist  is  fixed  upon  a  certain  train  of  thought, 
whatever  may  be  spoken  in  harmony  with  this  is  heard  and  appreciated,  but 
what  has  no  relation  to  it,  or  is  in  discordance  with  it,  is  entirely  disregarded. 
It  is  among  the  most  curious  of  the  numerous  facts  which  Mr.  Braid's  investi- 
gations upon  artificial  Somnambulism  have  brought  to  light,  that  the  sugges- 
tions derived  from  the  "  muscular  sense"  have  a  peculiar  potency  in  determin- 
ing the  current  of  thought.     For  if  the  face,  body,  or  limbs  be  brought  into  an 
attitude  that  is  expressive  of  any  particular  emotion,  or  that  corresponds  with 
that  in  which  it  would  be  placed  for  the  performance  of  any  voluntary  action, 
the  corresponding  mental  state — that  is,  either  an  emotional  condition  affecting 
the  general  direction  of  the  thoughts,  or  the  idea  of  a  particular  action — is 
called  up  in  respondence  to  it.     Thus,  if  the  hand  be  placed  upon  the  vertex, 
the  Somnambulist  will  frequently  of  his  own  accord,  draw  his  body  up  to  its 
fullest  height,  and  throw  his  head  slightly  back ;  his  countenance  then  assumes 
an  expression  of  the  most  lofty  pride,  and  the  whole  train  of  thought  is  obvi- 
ously under  the  domination  of   this  feeling,  as  is  manifested  by  the  replies 
which  the  individual  makes  to  interrogatories,  and  by  the  tone  and  manner  in 
which  these  are  delivered.     Where  the  first  action  does  not  of  itself  call  forth 
the  rest,  it  is  sufficient  to  straighten  the  legs  and  spine,  and  to  throw"  the  head 
somewhat  back,  to  arouse  the  emotion,  with  its  corresponding  manifestation,  in 
its  full  intensity.     If,  during  the  most  complete  domination  of  this  emotion, 
the  head  be  bent  forwards  and  the  body  and  limbs  be  gently  flexed,  the  most 
51 


802  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

profound  humility  then  takes  its  place.  So,  again,  if  the  angles  of  the  mouth 
be  gently  separated  from  one  another,  as  in  laughter,  a  hilarious  disposition  is 
immediately  generated ;  and  this  may  be  made  to  give  place  to  moroseness,  by 
drawing  the  eyebrows  towards  each  other  and  downwards  upon  the  nose,  as  in 
frowning.1  So,  again,  if  the  hand  be  raised  above  the  head,  and  the  fingers  be 
flexed  upon  the  palm,  the  idea  of  climbing,  swinging,  or  pulling  at  a  rope  is 
called  up  in  such  as  have  been  used  to  this  kind  of  exertion  ;  if,  on  the  other 
hand,  the  fingers  be  flexed  when  the  arm  is  hanging  down  at  the  side,  the  idea 
suggested  is  that  of  lifting  a  weight ;  and  if  the  same  flexure  be  made  when 
the  arm  is  advanced  forwards  in  the  position  of  striking  a  blow,  the  idea  of 
fighting  is  at  once  aroused,  and  the  Somnambulist  is  very  apt  to  put  it  into 
immediate  execution.2 

828.  The  state  of  Dreaming  presents  us  with  another  series  of  phenomena, 
which  fall  under  the  same  general  category  with  the  preceding.  In  fact, 
between  Dreaming  and  Somnambulism  there  is  every  stage  of  gradation  j  for 
that  form  of  Somnambulism  in  which  the  actions  are  expressive  of  ideas  that 
arise  spontaneously  within  the  mind,  instead  of  being  prompted  by  external 
suggestions,  may  be  designated  as  an  acted  dream ;  whilst,  on  the  other  hand, 
there  are  states  of  Dreaming,  in  which  the  bystander  is  able  in  greater  or  less 
degree  to  trace  the  current  of  thought  and  feeling,  by  the  words  occasionally 
uttered,  or  by  the  play  of  the  countenance  of  the  sleeper.  Instances  might  be 
cited,  which  it  would  be  very  difficult  to  assign  to  either  one  of  these  conditions, 
so  completely  do  they  partake  of  the  character  of  both ;  as  for  example,  the 
well-known  case  of  the  officer  who  amused  his  friends  by  acting  his  dreams  dur- 
ing the  expedition  to  Louisburgh,  the  course  of  these  dreams  being  capable  of 
direction  by  whispering  into  the  sleeper's  ear,  especially  if  this  was  done  by  a 
friend  with  whose  voice  he  was  familiar.3  It  is  usually  considered  to  be  a  dis- 
tinction between  Dreaming  and  Somnambulism,  that  the  senses  are  in  complete 
abeyance  in  the  former  state,  while  they  are  more  or  less  capable  of  action  in 
the  latter.  But  we  have  seen  that  the  sensibility  to  external  impressions  may 
be  partially  or  even  completely  suspended  in  Somnambulism  •  whilst,  on  the 
other  hand,  it  may  exist  to  a  slight  extent  in  Dreaming,  as  in  the  instance  just 
quoted.  And  it  is  quite  certain  that  even  where  sensations  are  not  recognized 
by  the  mind  as  proceeding  from  external  objects,  they  may  affect  the  course  of 
its  own  thoughts ;  so  that  the  character  of  the  dreams  may  be  in  some  degree 
predetermined  by  such  an  arrangement  of  sensory  impressions  as  is  likely  to 
modify  them.  This  is  especially  the  case  in  regard  to  the  dreamy  state  induced 

1  The  author  has  not  only  repeatedly  witnessed  all  these  effects,  as  produced  by  Mr. 
Braid  upon  "  hypnotized"   subjects,  of  whom  several  had  never  been  previously  in  that 
condition,  and  had  no  idea  whatever  of  what  was  expected  from  them ;  but  he  has  been 
assured  by  a  most  intelligent  medical  friend,  who  has  paid  special  attention  to  the  psycho- 
logical part  of  this  inquiry,  that,  having  subjected  himself  to  Mr.  Braid's  practice,  and 
having  been  only  partially  thrown  into  the  "hypnotic"  state,  he  distinctly  remembers 
everything  that  was  done,  and  can  retrace  the  uncontrollable  effect  upon  his  emotional  state, 
which  was  produced  by  this  management  of  his  muscular  apparatus. 

2  On  one  occasion  on  which  the  author  witnessed  this  result,  a  violent  blow  was  struck, 
which  chanced  to  alight  upon  a  second  somnambulist  within  reach  ;  his  combativeness 
being  thereby  excited,  the  two  closed,  and  began  to  belabor  one  another  with  such  energy, 
that  they  were  with  difficulty  separated.     Although  their  passions  were  at  the  moment  so 
strongly  excited,  that  even  when  separated  they  continued  to  utter  furious  denunciations 
against  each  other,  yet  a  little  discreet  manipulation  of  their  muscles  soon  calmed  them 
and  restored  them  to  perfect  good-humor. 

3  This  case  is  detailed  by  Dr.  Abercrombie  ("Inquiries  concerning  the  Intellectual 
Powers,"  5th  ed.,  p.  277),  on  the  authority  of  Dr.  Gregory,  to  whom  it  was  related  by  a 
gentleman  who  witnessed  it.     A  case  of  a  very  similar  nature,  the  subject  of  which 
was  a  medical  student  at  Edinburgh,  is  related  in  Suiellie's  "Philosophy  of  Natural 
History." 


THE    CEREBRUM,    AND   ITS   FUNCTIONS.  803 

by  certain  narcotics,  such  as  the  Hachisch  (a  preparation  of  Cannabis  Indica) 
employed  for  this  purpose  in  the  East ;  for  the  emotional  condition  of  the  in- 
dividual under  its  influence  is  entirely  under  the  control  of  external  impressions; 
so  that  those  who  give  themselves  up  to  the  intoxication  of  the  fantasia,  take  care 
to  withdraw  themselves  from  everything  which  could  give  their  delirium  a 
tendency  to  melancholy,  or  excite  in  them  anything  else  than  feelings  of  plea- 
surable enjoyment.1 — The  difference  between  the  state  of  mind  in  ordinary  Dream- 
ing and  that  which  is  characteristic  of  Somnambulism  is  most  remarkable  in  regard 
to  the  rapidity  and  incoherence  of  the  trains  of  thought  in  the  former  state, 
as  compared  with  the  slowness  and  steadiness  of  the  mental  action  usually  ob- 
served in  the  latter.  It  is  true  that  in  ordinary  dreaming  there  is  sometimes  a 
remarkable  degree  of  consistency  in  the  mental  operations;  for  reasoning  pro- 
cesses may  be  carried  on  correctly,  and  even  (through  that  freedom  from  dis- 
traction which  is  consequent  upon  the  suspension  of  external  disturbing  agen- 
cies) with  remarkable  vigor  and  completeness,  especially  when  they  are  the 
continuation  of  a  train  of  thought  on  which  the  mind  had  been  previously  en- 
gaged during  the  waking  hours;  and  music,  poetry,  &c.,  may  be  composed, 
which,  if  afterwards  remembered  and  written  down,  is  found  to  be  in  accordance 
with  the  rules  of  taste.  Such,  however,  is  not  the  usual  character  of  the  state 
of  dreaming ;  for  more  commonly  there  is  an  entire  want  of  any  ostensible 
coherence  between  the  ideas  which  successively  present  themselves  to  the  con- 
sciousness ;  and  we  are  completely  unaware  of  the  incongruousness  of  the  com- 
binations which  are  thus  formed.  It  has  been  well  remarked  that  "  nothing 
surprises  us  in  dreams."  All  probabilities  of  "  time,  place,  and  circumstance" 
are  violated ;  the  dead  pass  before  us  as  if  alive  and  well ;  even  the  sages  of 
antiquity  hold  personal  converse  with  us ;  our  friends  upon  the  antipodes  are 
brought  upon  the  scene,  or  we  ourselves  are  conveyed  thither,  without  the  least 
perception  of  the  intervening  distance ;  and  occurrences,  such  as  in  our  waking 
state  would  excite  the  strongest  emotions,  may  be  contemplated  without  the 
slightest  feeling  of  a  painful  or  pleasurable  nature.  Facts  and  events  long  since 
forgotten  in  the  waking  state,  present  themselves  to  the  mind  of  the  dreamer ; 
and  many  instances  have  occurred,  in  which  the  subsequent  retention  of  the 
knowledge  thus  re-acquired  has  led  to  most  important  results.2  But  one  of  the 
most  remarkable  of  all  the  peculiarities  in  the  state  of  dreaming,  is  the  rapidity 
with  which  trains  of  thought  pass  through  the  mind ;  for  a  dream  in  which  a 
long  series  of  events  has  seemed  to  occur,  and  a  multitude  of  images  has  been 
successively  raised  up,  has  been  often  certainly  known  to  have  occupied  only  a 
few  minutes,  or  even  seconds,  although  whole  years  may  seem  to  the  dreamer 
to  have  elapsed.  There  would  not  appear,  in  truth,  to  be  any  limit  to  the 
amount  of  thought  which  may  thus  pass  through  the  mind  of  the  dreamer,  in 
an  interval  so  brief  as  to  be  scarcely  capable  of  measurement ;  as  is  obvious 
from  the  fact,  that  a  dream  involving  a  long  succession  of  supposed  events,  has 
often  distinctly  originated  in  a  sound  which  has  also  awoke  the  sleeper,  so  that 
the  whole  must  have  passed  during  the  almost  inappreciable  period  of  transition 
between  the  previous  state  of  sleep  and  the  full  waking  consciousness.3  Hence 

1  See  the  Author's  article  "Sleep,"  in  the  "Cyclop,  of  Anat.  and  Phys.,"  vol.  iv.  pp. 
688 — 690;  and  Moreau  "  Du  Hachisch  et  de  1' Alienation  Mentale,  Etudes  Psychologiques," 
p.  67. 

2  See  a  number  of  such  cases  in  Dr.  Abercrombie's  "Inquiries  concerning  the  Intellec- 
tual Powers." 

3  The  only  phase  of  the  waking  state,  in  which  any  such  intensely  rapid  succession  of 
thoughts  presents  itself,  is  that  which  is  now  well  attested  as  a  frequent  occurrence,  under 
circumstances  in  which  there  is  imminent  danger  of  death,  especially  by  drowning ;  the 
whole  previous  life  of  the  individual  seeming  to  be  presented  instantaneously  to  his  view, 
with  its  every  important  incident  vividly  impressed  on  his  consciousness,  just  as  if  all  were 
combined  in  a  picture,  the  whole  of  which  could  be  taken  in  at  a  glance. 


804  OP  THE   FUNCTIONS  OP   THE   NERVOUS    SYSTEM. 

it  has  been  argued  by  some,  that  all  our  dreams  really  take  place  in  the  moment- 
ary passage  between  the  states  of  sleeping  and  waking;  but  such  an  idea  is  not 
consistent  with  the  fact  already  referred  to,  that  the  course  of  a  dream  may  often 
be  traced  by  observing  the  successive  changes  of  expression  in  the  countenance 
of  the  dreamer.  It  seems,  however,  that  those  dreams  are  most  distinctly 
remembered  in  the  waking  state,  which  have  passed  through  the  mind  during 
the  transitional  phase  just  alluded  to  ;  while  those  which  occur  in  a  state  more 
allied  to  Somnambulism,  are  more  completely  isolated  from  the  ordinary  con- 
sciousness.— There  is  a  phase  of  the  dreaming  state  which  is  worthy  of  notice, 
as  marking  another  gradation  between  this  and  the  vigilant  state ;  that,  namely, 
in  which  the  dreamer  has  a  consciousness  that  he  is  dreaming,  being  aware  of 
the  unreality  of  the  images  which  present  themselves  before  his  mind.  He  may 
even  make  a  voluntary  and  successful  effort  to  prolong  them  if  agreeable,  or  to 
dissipate  them  if  unpleasing ;  thus  evincing  the  possession  of  a  certain  degree 
of  that  directing  power,  the  entire  want  of  which  is  the  characteristic  of  the 
true  state  of  Dreaming. 

829.  Very  nearly  allied  to  the  states  of  Somnambulism  and  Dreaming,  are 
those  of  Delirium  and  of  Mania,  which  graduate  almost  imperceptibly  into  one 
another ;  being  chiefly  distinguished  by  the  degree  and  kind  of  excitement 
which  they  respectively  exhibit,  and  by  the  nature  of  the  bodily  states  with 
which  they  are  connected.  The  loss  of  voluntary  control  over  the  current  of 
thought  is  the  primary  element  of  both  these  conditions ;  and  the  gradual  weak- 
ening of  this  may  be  frequently  traced,  when  the  transition  from  the  normal 
state  is  not  so  rapid  as  to  prevent  its  various  steps  from  being  watched.  The 
artificial  delirium  produced  by  intoxicating  agents  affords  peculiar  facilities  for 
this  kind  of  observation  ;  and  among  these  agents,  there  is  none  whose  operation 
is  so  interesting  in  this  respect  as  the  Hachisch.  The  first  effect  of  a  dose  of 
this  substance,  as  described  by  M.  Moreau  (Op.  cit.),  is  commonly  to  produce 
a  moderate  exhilaration  of  the  feelings,  and  an  unusual  activity  of  the  intellec- 
tual powers ;  but  this  activity  gradually  frees  itself  from  the  control  of  the  Will. 
The  individual  feels  himself  incapable  of  fixing  his  attention  upon  any  subject; 
his  thoughts  being  continually  drawn  off  by  a  succession  of  ideas  which  force 
themselves  (as  it  were)  into  his  mind,  without  his  being  in  the  least  able  to 
trace  their  origin.  These  speedily  occupy  his  attention,  and  present  themselves 
in  strange  combinations,  so  as  to  produce  the  most  fantastic  and  impossible  crea- 
tions. By  a  strong  effort  of  volition,  however,  the  original  thread  of  the  ideas 
may  be  recovered,  and  the  interlopers  driven  away.  These  "  lucid  intervals" 
successively  become  of  shorter  and  shorter  duration,  and  can  be  less  frequently 
procured  by  a  voluntary  effort;  for  the  internal  tempest  becomes  more  and  more 
violent,  the  torrent  of  (apparently)  disconnected  ideas  increases  in  vehemence, 
so  as  completely  to  arrest  the  attention,  and  the  mind  is  at  last  entirely  given 
up  to  it,  and  at  the  same  time  withdrawn  from  the  perceptive  consciousness  of 
external  things,  although,  as  already  pointed  out  (§  828),  it  is  by  no  means 
removed  from  the  influence  of  sensory  impressions.  The  succession  of  ideas  has 
at  first  less  of  incoherence  than  in  ordinary  dreaming,  the  ideal  events  not 
departing  so  widely  from  possible  realities ;  and  the  disorder  of  the  mind  is  at 
first  manifested  in  errors  of  perception,  in  false  convictions,  or  in  the  predomi- 
nance of  one  or  more  extravagant  notions.  These  false  ideas  are  generally  not 
altogether  of  an  imaginary  character,  but  are  originally  called  into  existence  by 
external  impressions,  these  being  erroneously  interpreted  through  the  disor- 
dered action  of  the  perceptive  faculty  ;  thus,  for  example,  among  the  most  com- 
mon perversions  are  those  relating  to  time  and  space,  minutes  seeming  hours, 
hours  being  prolonged  into  years,  and  all  idea  of  time  being  at  last  obliterated, 
so  that  past  and  present  are  confounded  together  as  in  ordinary  dreaming  : 
whilst  in  like  manner  streets  may  appear  of  an  interminable  length,  the  people 
at  the  other  end  seeming  to  be  at  a  vast  distance ;  the  mind  having  a  tendency  to 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  805 

exaggerate  every  impression  made  upon  the  consciousness,  especially  those  which 
affect  the  emotional  state.  The  effect  of  a  full  dose,  however,  is  at  last  to  pro- 
duce the  complete  withdrawal  of  the  mind  from  the  contemplation  of  external 
things,  and  entirely  to  suspend  the  action  of  the  will  over  the  current  of 
thought ;  and  the  condition  then  comes  to  be  nearly  the  same  as  that  of  ordi- 
nary Dreaming,  the  chief  difference  consisting  in  the  readiness  with  which  the 
emotions  may  be  excited  in  those  who  are  under  the  influence  of  the  Hachisch, 
and  in  the  degree  in  which  these  are  amenable  to  external  influences. — The  fol- 
lowing concise  and  faithful  description  of  the  ordinary  Delirium  of  disease  will 
show  how  completely  it  corresponds  in  all  its  essential  characters  with  that 
which  is  induced  by  the  introduction  of  intoxicating  agents  into  the  blood. 
a  In  its  highest  degree,  it  is  a  complete  disturbance  of  the  intellectual  actions; 
the  thoughts  are  not  inactive,  but  rather  far  more  active  than  in  health  ;  they 
are  uncontrolled,  and  wander  from  one  subject  to  another  with  extraordinary 
rapidity;  or,  taking  up  one  single  subject,  they  twist  and  turn  it  in  every  way 
and  shape,  with  endless  and  innumerable  repetitions.  The  thinking  faculty 
seems  to  have  escaped  from  all  control  and  restraint,  and  thought  after  thought 
is  engendered  without  any  power  of  the  patient  to  direct  and  regulate  them. 
Sometimes  they  succeed  each  other  with  such  velocity,  that  all  power  of  per- 
ception is  destroyed,  and  the  mind,  wholly  engrossed  with  this  rapid  develop- 
ment of  thoughts,  is  unable  to  perceive  impressions  made  upon  the  senses ;  the 
patient  goes  on  unceasingly  raving,  apparently  unconscious  of  what  is  taking 
place  around  him  ;  or  it  may  be,  that  his  senses  have  become  more  acute,  and 
that  every  word  from  a  bystander,  or  every  object  presented  to  his  vision,  will 
become  the  nucleus  of  a  new  train  of  thought ;  and,  moreover,  such  may  be 
the  exaltation  of  his  sensual  perception,  that  subjective  phenomena  will  arise  in 
connection  with  each  sense,  and  the  patient  fancies  he  hears  voices  or  other 
sounds,  whilst  ocular  spectra  in  various  forms  and  shapes  appear  before  his  eyes 
and  excite  further  rhapsodies  of  thought."1  It  must  be  remarked  that  there  is 
usually  a  greater  disorder  of  the  perceptive  faculty  in  Delirium  than  in  ordi- 
nary Dreaming;  for,  in  the  former  condition,  the  erroneous  images  are  more 
vividly  conceived  of  as  having  an  existence  external  to  the  mind,  than  they  are 
in  the  latter,  the  illusory  visual  and  auditory  perceptions  having  all  the  force  of 
reality,  and  being  the  original  sources  of  ideas,  instead  of  (as  seems  to  be  rather 
the  case  in  dreaming)  their  products.2 

1  See  Dr.  Todd's  "  Lumleian  Lectures,  on  the  Pathology  and  Treatment  of  Delirium  and 
Coma,"  in  the  "  Medical  Gazette,"  1850,  vol.  xlv.  p.  703. — A  circumstance  was  mentioned 
to  the  Author,  whilst  he  was  a  student  at  Edinburgh,  which  remarkably  illustrates  the 
influence  of  suggestions  derived  from  external  sources,  in  determining  the  current  of 
thought.     During  an  epidemic  of  Fever,  which  had  occurred  some  time  previously,  and  in 
which  an  active  delirium  had  been  a  common  symptom,  it  was  observed  that  many  of  the 
patients  of  one  particular  physician  were  possessed  by  a  strong  tendency  to  throw  them- 
selves out  of  the  window,  whilst  no  such  tendency  presented  itself  in  unusual  frequency 
in  the  practice  of  others.     The  Author's  informant,  himself  a  distinguished  Professor  in 
the  University,  explained  this  tendency  by  what  had  occurred  within  his  own  knowledge, 
as  follows:  His  friend  and  colleague,  Dr.  A.,  was  attending  a  patient,  Mr.  B.,  who  seems 
to  have  been  the  first  to  make  the  attempt  in  question ;  impressed  with  the  necessity  of 
taking  due  precautions,  Dr.  A.  then  visited  Dr.  C.,  in  whose  hearing  he  gave  directions  to 
have  the  windows  properly  secured,  as  Mr.  B.  had  attempted  to  throw  himself  out.     Now 
Dr.  C.  distinctly  remembers  that,  although  he  had  not  previously  experienced  any  such 
desire,  it  came  upon  him  with  great  urgency  as  soon  as  ever  the  idea  was  thus  suggested 
to  him ;  his  mind  being  just  in  that  state  of  incipient  delirium,  which  is  marked  by  the 
temporary  dominance  of  some  one  idea,  and  by  the  want  of  voluntary  power  to  with- 
draw the  attention  from  it.     And  he  deemed  it  probable  that,  as  Dr.  A.  went  on  to  Mr. 
D.,  Dr.  E.,  &c.,  and  gave  similar  directions,  a  like  desire  would  be  excited  in  the  minds  of 
all  those  who  happened  to  be  in  the  same  impressible  condition. 

2  In  true  Dreaming,   the  sensational  consciousness  is  entirely  closed  to  the  outward 
world ;  arid  all  the  images  which  we  may  believe  we  see,  or  the  sounds  that  we  fancy  our- 


806  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

830.  Those  more  violent  forms  of  Delirium  in  which  there  is  considerable 
emotional  disturbance,  pass  by  almost  imperceptible  gradations  into  the  state  of 
Mania,  which  is  usually  characterized  by  the  combination  of  complete  derange- 
ment of  the  intellectual  powers,  with  passionate  excitement  upon  every  point 
which  in  the  least  degree  affects  the  feelings.  There  is,  however,  a  considerable 
amount  of  variety  in  the  phases  of  Mania,  depending  upon  differences  in  the 
relative  degree  of  intellectual  and  of  emotional  disturbance.  For  there  may  be 
such  a  derangement  of  the  former,  as  gives  rise  to  complete  incoherence  in  the 
succession  of  ideas,  so  that  the  reasoning  power  is  altogether  suspended;  and 
yet  there  may  be  at  the  same  time  an  entire  absence  of  emotional  excitement, 
so  that  the  condition  of  the  mind  is  closely  allied  to  that  of  dreaming  or  of 
rambling  delirium.  On  the  other  hand,  the  intellectual  powers  may  be  them- 
selves but  little  disturbed,  the  trains  of  thought  being  coherent,  and  the  reason- 
ing processes  correctly  performed ;  but  there  may  be  such  a  state  of  general 
emotional  excitability,  that  nothing  is  felt  as  it  should  be,  and  the  most  violent 
passion  may  be  aroused  and  sustained  by  the  most  trivial  incidents,  or  by  the 
wrong  ideas  which  are  formed  by  the  mind  as  a  consequence  of  their  misinter- 
pretation (§  796).  Between  these  two  opposite  states,  and  that  in  which  the 
disturbance  affects  at  the  same  time  the  intellectual  and  the  emotional  part  of 
the  Mental  nature,  there  is  a  complete  succession  of  transitional  links ;  but, 
under  all  phases  of  this  condition  (these  often  passing  into  each  other  in  the 
same  individual),  there  is  one  constant  element,  namely,  the  deficiency  of  Voli- 
tional control  over  the  succession  of  ideas.  This  deficiency  appears  to  be  a 
primary  element  in  those  forms  which  essentially  consist  in  Intellectual  dis- 
turbance; whilst  in  those  of  which  Emotional  excitement  is  the  prominent 
feature,  it  seems  rather  to  result  from  the  overpowering  mastery  that  is  exer- 
cised over  the  Will,  by  the  states  of  uncontrollable  passion  which  succeed  each 
other  with  little  or  no  interval.  It  seems  probable,  however,  from  the  pheno- 
mena of  Intoxication  (§  829),  that  the  very  same  agency  which  is  the  cause  of 
the  undue  Emotional  excitability,  also  tends  to  produce  an  absolute  diminution 
in  the  power  of  Volitional  control. 

881.  From  the  state  of  Mania,  we  naturally  pass  to  those  more  persistent 
forms  of  Insanity,  in  which  there  is  some  settled  disorder  in  the  action  of  the 
Mind.  Although  this  may  arise  from  a  perversion  of  any  part  of  the  psychical 
nature,  yet  a  partial  or  complete  deficiency  in  the  Volitional  control  over  the 
current  of  thought,  and  consequently  over  the  actions  which  are  the  expressions 
of  it,  seems  to  be  a  characteristic  feature  of  every  form  of  Insanity ;  and  it  is 
this,  which,  in  so  far  as  it  exists,  ought  to  be  considered  as  rendering  the  indi- 
vidual irresponsible  for  his  actions. — It  is  chiefly  (but  not  solely)  in  those  cases 
in  which  the  Cerebral  power  has  been  weakened  by  a  succession  of  attacks  of 
Mania,  Epilepsy,  or  some  other  disorder  which  consists  in  a  perverted  action  of 
the  whole  organ,  that  we  find  the  Intellectual  powers  specially  and  permanently 
disordered ;  the  succession  of  thought  becoming  incoherent,  and  the  perception 
of  those  relations  of  ideas  on  which  all  reasoning  processes  depend,  being  more 
or  less  completely  obscured.  The  failure  usually  shows  itself  first  in  the  power 
of  Volitional  direction,  and  especially  in  the  faculty  of  Recollection;  in  propor- 
tion as  the  mind  is  unable  to  bring  the  results  of  past  experience  to  bear  on  its 
present  operations,  do  these  lose  their  connectedness  and  consistency ;  and  at 
last  all  the  ordinary  links  of  association  appear  to  be  severed,  and  (as  in  the 
most  incoherent  kinds  of  Dreaming)  the  succession  of  thoughts  cannot  be  ac- 

selves  to  hear,  seem  to  result  from  changes  in  the  Sensorium  excited  by  Cerebral  influence ; 
but  in  Delirium  there  is  an  evidently  disordered  action  of  the  sensorium  itself,  of  which 
spectral  illusions  and  other  "subjective  sensations"  are  the  manifestation.  This  is  par- 
ticularly obvious  in  that  form  of  Delirium  which  is  known  as  delirium  tremens. 


THE    CEREBRUM,    AND   ITS   FUNCTIONS.  807 

counted  for  on  any  known  principles  of  psychical  action.  All  this  may  occur 
with  or  without  emotional  excitement ;  not  unfrequently  the  latter  occurs  in 
paroxysms,  which  interrupt  the  otherwise  tranquil  life  of  the  subjects  of  this 
form  of  Insanity,  and  it  is  not  at  all  incompatible  with  this  condition,  that  there 
should  be  a  special  excitability  upon  some  one  point,  which,  owing  to  the  anni- 
hilation of  the  Volitional  controlling  power,  acquires  a  temporary  predominance 
whenever  it  is  called  into  play.  It  is  the  general  characteristic,  however,  of 
this  form  of  Insanity,  that  there  are  no  settled  delusions;  the  mind  not  being 
disposed  to  dwell  long  upon  any  one  topic,  but  wandering  off  in  a  rambling 
manner,  so  as  speedily  to  lose  all  trace  of  the  starting-point.  Such  patients 
are  unable  to  recollect  what  passed  through  their  thoughts  but  a  few  minutes 
previously ;  if  any  object  of  desire  be  placed  before  them,  which  it  requires  a 
consistent  reasoning  process  to  attain,  they  are  utterly  unable  to  carry  this 
through  ;  and  the  direction  of  their  desires  is  perpetually  varying,  and  may  be 
readily  altered  by  external  suggestion.  Cases  of  Intellectual  Insanity,  depend- 
ing (as  this  form  of  the  disease  usually  does)  upon  structural  disorder  of  the 
Cerebrum,  are  less  amenable  to  treatment  than  are  those  of  the  other  forms  pre- 
sently to  be  described;  and  their  tendency  is  usually  towards  complete  fatuity. 
832.  There  may,  however,  be  no  primary  disorder  of  the  Intellectual  facul- 
ties ;  and  the  Insanity  may  essentially  consist  in  a  tendency  to  disordered 
Emotional  excitement ;  which  affects  the  course  of  thought,  and  consequently 
of  action,  without  disordering  the  reasoning  processes  in  any  other  way  than  by 
supplying  wrong  materials  to  them.  Now  the  emotional  disturbance  may  be 
either  general  or  special;  that  is,  there  may  be  a  derangement  of  feeling  upon 
almost  every  subject,  matters  previously  indifferent  becoming  invested  with 
strong  pleasurable  or  painful  interest,  things  which  were  previously  repulsive 
being  greedily  sought,  and  those  which  were  previously  the  most  attractive 
being  in  like  manner  repelled;  or,  on  the  other  hand,  there  may  be  a  peculiar 
intensification  of  some  one  class  of  feelings  or  impulses,  which  thus  acquire  a 
settled  domination  over  the  whole  character,  and  cause  every  idea  with  which 
they  connect  themselves  to  be  presented  to  the  mind  under  an  erroneous  aspect. 
The  first  of  these  forms,  now  generally  termed  Moral  Insanity,  may  and  fre- 
quently does  exist  without  any  disorder  of  the  Intellectual  powers,  or  any 
delusion  whatever ;  it  being  (as  we  shall  presently  see)  a  result  of  the  gene- 
rality of  the  affection  of  the  Emotional  tendencies,  that  no  one  of  them  main- 
tains any  constant  hold  upon  the  mind,  one  excitement  being  (as  it  were) 
driven  out  by  another.  Such  patients  are  among  those  whose  treatment 
requires  the  nicest  care,  but  who  may  be  most  benefited  by  judicious  influences. 
Nothing  else  is  requisite,  than  that  they  should  exercise  an  adequate  amount  of 
self-control;  but  the  best  directed  moral  treatment  cannot  enforce  this,  if  the 
patient  do  not  himself  (or  herself1)  co-operate.  Much  may  be  effected,  however, 
as  in  the  education  of  children,  by  presenting  adequate  motives  to  self-control ; 
and  the  more  frequently  this  is  exerted,  the  more  easy  does  the  exertion  become. 
— The  more  limited  and  settled  disorder  of  any  one  portion  of  the  Emotional 
nature,  however,  gives  an  entirely  different  aspect  to  the  character,  and  pro- 
duces an  altogether  dissimilar  effect  upon  the  conduct.  It  is  the  essential 
feature  of  this  state,  that  some  one  particular  tendency  acquires  a  dominance 
over  the  rest;  and  this  may  happen,  it  would  seem,  either  from  an  extraordinary 
exaggeration  of  the  tendency,  whereby  it  comes  to  overmaster  even  a  strongly- 
exercised  Volitional  control;  or,  on  the  other  hand,  from  a  primary  weakening 
of  the  Volitional  control,  which  leaves  the  predominant  bias  of  the  individual 

1  This  form  of  Insanity  is  particularly  common  among  females  of  naturally  "quick 
temper,"  who,  by  not  placing  an  habitual  restraint  upon  themselves,  gradually  cease  to 
retain  any  command  over  it. 


808  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

free  to  exercise  itself.  Again,  the  exaggerated  tendency  may  operate  (like  an 
ordinary  Emotion)  either  in  directly  prompting  to  some  kind  of  action  which  is 
the  expression  of  it;  or  in  modifying  the  course  of  thought,  by  habitually  pre- 
senting erroneous  notions  upon  the  subjects  to  which  the  disordered  feeling 
relates,  as  the  basis  of  Intellectual  operations.  The  first  of  these  forms  of 
Monomania  is  that  which  is  known  as  impulsive  Insanity;  and  the  recognition 
of  its  existence  is  of  peculiar  importance  in  a  juridical  point  of  view.  For 
whilst  the  Law  of  England  only  recognizes  as  irresponsible,  on  the  ground  of 
Insanity,  those  who  are  incapable  of  distinguishing  right  from  wrong,  or  of 
recognizing  the  consequences  of  their  acts,  it  is  unquestionable  that  many 
criminal  actions  are  committed  under  the  irresistible  dominance  of  some  insane 
impulse,  the  individual  being  at  the  time  perfectly  aware  of  their  evil  nature 
and  of  his  amenableness  to  punishment.1  Such  an  impulse  may  lead  the  sub- 
ject of  it  to  kill,  to  commit  a  rape,  to  steal,  to  burn,  and  so  on,  and  this 
without  the  least  intention  of  doing  injury  to  another;  and  many  instances  have 
occurred,  in  which  the  individuals  thus  affected  have  voluntarily  withdrawn 
themselves  from  the  circumstances  of  whose  exciting  influence  they  were  con- 
scious, and  have  even  begged  to  be  put  under  restraint. — It  is  a  remarkable 
fact,  moreover,  and  one  that  strikingly  confirms  the  view  of  the  nature  of 
Emotional  states  which  has  been  here  advocated,  that  the  insane  impulse  ap- 
pears to  be  not  unfrequently  the  expression  of  a  dominant  idea,  with  which 
there  is  no  such  association  of  pleasurable  feeling  as  makes  the  action  prompted 
by  it  an  object  of  desire,  but  which  operates  by  taking  full  possession  of  the 
mind,  and  by  forcing  (so  to  speak)  the  body  into  the  movements  which  express 
it.  The  individual  thus  affected  regards  himself  as  the  victim  of  a  necessity 
which  he  cannot  resist,  and  may  be  perfectly  conscious  (as  when  the  impulse 
proceeds  from  a  strong  desire)  that  what  he  is  doing  will  be  injurious  to  others 

1  The  following  very  characteristic  example  of  the  Homicidal  form  of  impulsive  Insanity 
is  given  in  one  of  the  recent  Reports  of  the  Morningside  (Edinburgh)  Lunatic  Asylum. — 
The  case  was  that  of  a  female,  who  was  not  affected  with  any  disorder  of  her  intellectual 
powers,  and  who  labored  under  no  delusions  or  hallucinations,  but  who  was  tormented  by 
"a  simple  abstract  desire  to  kill,  or  rather,  for  it  took  a  specific  form,  to  strangle.  She 
made  repeated"  attempts  to  effect  her  purpose,  attacking  all  and  sundry,  even  her  own 
nieces  and  other  relatives ;  indeed,  it  seemed  to  be  a  matter  of  indifference  to  her  whom 
she  strangled,  so  that  she  succeeded  in  killing  some  one.  She  recovered,  under  strict 
discipline,  so  much  self-control  as  to  be  permitted  to  work  in  the  washing-house  and 
laundry,  but  she  still  continued  to  assert  that  she  'must  do  it,'  that  she  was  'certain  she 
would  do  it  some  day,'  that  she  'could  not  help  it,'  that  '  surely  no  one  had  ever  suffered 
as  she  had  done' — was  not  hers  'an  awful  case;'  and,  approaching  any  one,  she  would 
gently  bring  her  hand  near  their  throat,  and  say  mildly  and  persuasively,  '  I  would  just 
like  to  do  it.'  She  frequently  expressed  a  wish  that  all  the  men  and  women  in  the  world 
had  only  one  neck,  that  she  might  strangle  it.  Yet  this  female  had  kind  and  amiable 
dispositions,  was  beloved  by  her  fellow-patients,  so  much  so  that  one  of  them  insisted  on 
sleeping  with  her,  although  she  herself  declared  that  she  was  afraid  she  would  not  be 
able  to  resist  the  impulse  to  get  up  during  the  night  and  strangle  her.  She  had  been  a 
very  pious  woman,  exemplary  in  her  conduct,  very  fond  of  attending  prayer-meetings, 
and  of  visiting  the  sick,  praying  with  them,  and  reading  the  Scriptures,  or  repeating  to 
them  the  sermons  she  had  heard.  It  was  the  second  attack  of  insanity.  During  the 
former,  she  had  attempted  suicide.  The  disease  was  hereditary,  and  it  may  be  believed 
that  she  was  strongly  predisposed  to  morbid  impulses  of  this  character,  when  it  is  stated 
that  her  sister  and  mother  both  committed  suicide.  There  could  be  no  doubt  as  to  the 
sincerity  of  her  morbid  desires.  She  was  brought  to  the  Institution  under  very  severe 
restraint,  and  the  parties  who  brought  her  were  under  great  alarm  upon  the  restraint 
being  removed.  After  its  removal,  she  made  repeated  and  very  determined  attacks  upon 
the  other  patients,  the  attendants,  and  the  officers  of  the  Asylum,  and  was  only  brought 
to  exercise  sufficient  self-control  by  a  system  of  rigid  discipline.  This  female  was  per- 
fectly aware  that  her  impulses  were  wrong,  and  that  if  she  had  committed  any  act  of 
violence  under  their  influence,  she  would  have  been  exposed  to  punishment.  She  deplored, 
in  piteous  terms,  the  horrible  propensity  under  which  she  labored." 


THE    CEREBRUM,    AND   ITS    FUNCTIONS.  809 

or  to  himself.  This  state  bears  a  close  resemblance  to  that  of  the  "biologized" 
subject,  who  is  peremptorily  told:  "  You  must  do  this,"  and  does  it  accordingly 
(§  825) ;  and  it  is  one  that  is  particularly  liable  to  be  induced  in  persons  who 
habitually  exercise  but  little  Volitional  control  over  the  direction  of  their 
thoughts,  by  the  influence  of  suggestions  from  without,  and  especially  by  oc- 
currences which  fix  themselves  strongly  upon  their  attention.1 

833.  Now  although  the  existence  of  any  morbidly  exaggerated  impulse, 
leading  to  the  commission  of  acts  which  must  be  regarded  as  truly  Insane,  may 
be  fairly  considered  as  constituting  Monomania,  yet  that  term  is  usually  re- 
stricted to  those  forms  of  Insanity  in  which  there  are  positive  delusions  or  hal- 
lucinations, that  is  to  say,  fixed  beliefs  which  are  palpably  inconsistent  with 
reality.  These  delusions  are  not  attributable  to  perversions  of  the  reasoning 
process,  but  arise  out  of  the  perverted  Emotional  state.  This  gives  rise,  in  the 
first  place,  to  a  misinterpretation  of  actual  occurrences  in  accordance  with  the 
prevalent  state  of  the  feelings  (§  796) ;  but,  when  the  disorder  has  lasted  some 
time,  ideas  which  the  imagination  at  first  presents  under  a  very  transient  aspect, 
are  habitually  dwelt  upon  in  consequence  of  the  interest  with  which  they  are 
invested,  and  at  last  become  realities  to  the  consciousness  of  the  individual, 
simply  because  he  has  not  brought  them  to  the  test  of  actual  experience.  When 
the  mind  has  once  yielded  itself  up  to  the  dominance  of  these  erroneous  ideas, 
they  can  seldom  be  dispelled  by  any  process  of  reasoning ;  for  it  results  from 
the  very  nature  of  the  previous  habits  of  thought  that  the  reasoning  powers  are 
weakened,  and  that  the  volitional  control,  through  want  of  exercise,  can  no 
longer  be  exerted.  And  consequently,  although  a  vigorous  determination  to 
get  rid  of  the  ideas  which  are  felt  to  be  erroneous,  and  to  keep  down  the  emo- 
tional tendency  whose  exaggeration  is  the  essence  of  the  disorder — in  other 
words,  a  strong  effort  of  self-control — may  be  effective  in  an  early  stage  of  this 
condition,2  yet,  when  the  wrong  habits  of  thought  have  become  settled,  little 

1  To  this  condition  are  to  be  referred  many  of  the  insane  actions  which  are  commonly 
set  down  to  the  account  of  Imitation.     This  term  would  be  best  restricted  to  that  state  of 
mind,  in  which  there  is  an  intention  to  imitate;  for  what  is  called  "involuntary  imitation" 
is  merely  the  expression  of  the  fact  that  the  consciousness  of  the  performance  of    a 
certain   act  by  one  individual  gives  rise  to  a  tendency  to  its  performance  by  the  other. 
Thus  the  excitement  of  the  act  of  yawning  by  the  sight  or  the  sound  of  it  in  another,  is 
a  simple  phenomenon  of  consensual  movement  proceeding  from  an  exciting  sensation.     And 
in  like  manner,  the  commission  of  suicide  or  homicide,  after  an  occurrence  of  the  same 
kind  which  has  previously  fixed  itself  strongly  upon  the  attention,  is  an  ideo-motor  action, 
prompted  by  a  suggesting  idea.     Thus,  it  is  well  known  that  after  the  suicide  of  Lord 
Castlereagh,  a  large  number  of  persons  destroyed  themselves  in  a  similar  mode.     Within  a 
week  after  the  "Pentonville  Tragedy,"  in  which  a  man  cut  the  throats  of  his  four  chil- 
dren and  then  his  own,  there  were  two  similar  occurrences  elsewhere.     After  the  trial  of 
Henriette  Cornier  for  child-murder,  which  excited  a  considerable  amount  of  public  dis- 
cussion on   the  question  of  homicidal   insanity,  Esquirol  was   consulted   by   numerous 
mothers,  who  were  haunted  by  a  propensity  to  destroy  their  offspring. — The  following  is 
a  remarkable  example  of  the  sudden  domination  of  a  morbid  impulse,  to  which  no  tendency 
seems  to  have  been  previously  experienced,  and  which  appears  to  have  been  altogether  devoid 
of  any  emotional  character.     Dr.  Oppenheim,  of  Hamburgh,  having  received  for  dissection 
the  body  of  a  man  who  had  committed  suicide  by  cutting  his  throat,  but  who  had  done  this  in 
such  a  manner  that  his  death  did  not  take  place  until  after  an  interval  of  great  suffering, 
jokingly  remarked  to  his  attendant:   "If  you  have  any  fancy  to  cut  your  throat,  don't  do 
it  in  such  a  bungling  way  as  this ;  a  little  more  to  the  left  here,  and  you  will  cut  the 
carotid  artery."     The  individual  to  whom  this  dangerous  observation  was  addressed  was 
a  sober,  steady  man,  with  a  family  and  a  comfortable  subsistence ;  he  had  never  mani- 
fested the  slightest  tendency  to  suicide,  and  had  no  motive  to  commij  it.     Yet,  strange  to 
say,  the  sight  of  the  corpse,  and  the  observation  made  by  Dr.  0.  suggested  to  his  mind 
the  idea  of  self-destruction;  and  this  took  such  firm  hold  of  him  that  he  carried  it  into 
execution,  fortunately,  however,  without  duly  profiting  by  the  anatomical  instructions  he 
had  received ;  for  he  did  not  cut  the  carotid,  and  recovered. 

2  See  an  excellent  little  essay  by  the  Rev.  J.  Barlow,  on  "Man's  Power  over  himself  to 


810  OP   THE   FUNCTIONS   OP   THE   NERVOUS    SYSTEM. 

can  usually  be  done  by  way  of  direct  attack  upon  them  ;  and  the  most  efficacious 
treatment  consists  in  the  encouragement  of  the  general  habit  of  self-control,  and 
in  the  withdrawal  of  the  mind,  so  far  as  may  be  possible,  from  the  morbid 
state  of  action,  by  presenting  to  it  other  sources  of  interesting  occupation. 

834.  Returning  now  from  the  consideration  of  these  Pathological  conditions  of 
Mind  (as  they  may  be  not  unfairly  designated)  to  the  examination  of  the  Psychi- 
cal constitution  of  Man  in  the  state  of  normal  activity  of  all  his  faculties,  we 
shall  find  that  very  important  data  may  be  drawn  from  these  sources,  with  re- 
gard to  the  modus  operandi  of  the  Will,  and  the  manner  in  which  our  conduct 
is  determined.  For  we  have  seen  that,  in  so  far  as  the  directing  influence  of 
the  Will  over  the  current  of  thought  is  suspended,  the  individual  becomes  a 
thinking  automaton,  destitute  of  the  power  to  withdraw  his  attention  from  any 
idea  or  feeling  by  which  his  mind  may  be  possessed,  and  as  irresistibly  impelled, 
therefore,  to  act  in  accordance  with  this,  as  the  lower  animals  are  to  act  in  ac- 
cordance with  their  instincts.  In  so  far,  therefore,  as  this  directing  influence 
is  not  exercised,  the  succession  of  trains  of  thought  which  occupy  the  conscious- 
ness (associated,  or  not,  with  feelings  that  give  them  an  emotive  character)  must 
be  considered  as  dependent  on  the  "  reflex  action"  of  the  Cerebrum  }  the  nature 
of  this  action  being  determined,  not  merely  by  the  original  constitution  of  the 
organ,  but  by  the  mode  in  which  it  has  been  subsequently  exercised ;  its  nutri- 
tion taking  place  in  such  conformity  to  the  impressions  made  upon  it,  and  to  the 
modes  in  which  it  is  habitually  directed  by  the  Will,  that  it  grows  to  these,  so 
that  a  new  organization  thus  comes  to  be  established,  by  which  habits  of  thought 
are  determined,  such  as  would  not  have  arisen  from  its  original  constitution.1 

prevent  or  control  insanity." — It  may  be  well  for  the  Author  to  state,  that  he  was  led, 
several  years  since,  to  the  formation  of  the  view  above  enunciated  with  regard  to  the  emo- 
tional source  of  most  if  not  all  the  delusions  of  the  Insane,  by  the  careful  observation  of  a 
case  in  which  the  gradual  formation  of  such  delusions  could  be  traced,  and  in  which  the 
varying  tenacity  of  their  hold  over  the  belief  (which  sometimes  appeared  disposed  to  get 
rid  of  them)  corresponded  exactly  with  varying  degrees  of  intensity  of  the  dominant  emo- 
tion. Having  been  led,  by  his  interest  in  this  case,  to  make  particular  inquiries  as  to  the 
point  in  question,  among  those  whose  experience  of  Insanity  has  been  far  more  extensive 
than  his  own,  he  has  obtained  from  them  full  confirmation  of  the  view  above  expressed. — 
It  is  not  a  little  interesting,  in  this  connection,  as  well  as  in  the  additional  relation  which 
it  indicates  between  Insanity  and  the  various  phases  of  Dreaming,  Delirium,  &c.,  that  the 
particular  delusion  seems  often  to  be  suggested  by  accidental  circumstances,  the  mind  being 
previously  under  the  influence  of  the  morbid  tendency  which  gave  the  peculiar  direction  to 
the  thoughts.  Thus  we  find  it  mentioned  in  the  "Morningside  Report,"  from  which  we 
have  already  quoted,  that  the  Queen's  public  visit  to  Scotland  seemed  to  give  a  special 
direction  to  the  ideas  of  several  individuals  who  became  insane  at  that  period,  the  attack 
of  insanity  being  itself  in  some  instances  traceable  to  the  excitement  induced  by  that  event. 
One  of  the  patients,  who  was  affected  with  puerperal  mania,  believed  that  in  consequence 
of  her  confinement  having  taken  place  on  such  a  remarkable  occasion,  she  must  have  given 
birth  to  a  person  of  royal  or  divine  dignity.  During  the  religious  excitement  which  pre- 
vailed at  the  time  of  the  "disruption"  of  the  Scotch  Church,  an  unusually  large  number 
of  patients  were  admitted  into  the  various  asylums  of  Scotland,  laboring  under  delusions 
connected  with  religion ;  the  disorder  having  here  also  doubtless  commenced  in  an  exaggera- 
tion of  this  class  of  feelings,  and  the  erroneous  beliefs  having  been  formed  under  their  in- 
fluence. Again,  in  the  Report  of  the  same  Institution  for  1851,  it  is  stated  that,  as  in 
former  instances,  "the  current  topics  of  the  day  gave  coloring  and  form  to  the  delusions 
of  the  disordered  fancy.  We  have  thus  had  no  less  than  five  individuals  admitted  during 
the  year,  who  believe  themselves  the  victims  of  Mesmeric  agency" — a  sort  of  "  Mesmeric 
mania"  having  been  prevalent  in  Edinburgh  during  that  period — "three  of  the  inmates 
talked  much  of  California,  and  of  the  bags  full  of  gold  which  they  had  obtained  from  the 
diggings  ;  and  one  ^f  them  arrived  at  the  persuasion  that  his  body  was  transmuted  into 
gold." 

1  See  Dr.  Laycock's  Essay  "  On  the  Reflex  Function  of  the  Brain,"  in  the  "Brit,  and 
For.  Med.  Review,"  vol.  xix.  p.  298. — If  it  be  thought  that,  in  the  above  expressions, 
there  is  too  much  of  a  Materialistic  character,  the  author  would  beg  to  refer  back  to  the 


THE   CEREBRUMj   AND   ITS   FUNCTIONS.  811 

The  variety  of  phases  which  these  different  states  present  is  chiefly  dependent 
upon  the  following  elements  :  (1)  the  relative  degree  in  which  the  Mind  is  in 
a  state  of  receptivity  for  external  impressions,  or  is  attending  only  to  what 
passes  within  itself;  (2)  the  degree  in  which  the  coherence  of  the  successive 
states  is  maintained  by  the  continuance  and  right  operation  of  the  preformed 
associations,  so  that  trains  of  thought  are  consistently  carried  out,  and  reason- 
ing processes  correctly  performed  ;  and  (3)  the  degree  in  which  the  normal  ope- 
ration of  the  intellectual  faculties  is  disturbed  by  emotional  excitement,  either 
general,  or  limited  to  one  class  of  feelings.  The  influence  of  i^Q  first  of  these 
elements  is  remarkably  seen  in  the  contrast  between  natural  and  artificial  Reverie 
(§§  824,  825)  ;  also  between  some  forms  of  natural  and  artificial  Somnambulism 
(§  827)  ;  and  not  less  between  different  forms  of  Insanity,  since  in  this 
last  condition  we  find  some  patients  constantly  brooding  over  particular  trains 
of  thought,  and  almost  incapable  of  being  turned  from  the  contemplation  of 
these  by  external  suggestions,  whilst  others  are  no  less  remarkable  for  the  in- 
stability of  their  mental  states,  and  for  the  readiness  with  which  a  new  direction 
may  be  given  to  the  thoughts  by  sensory  impressions.  The  influence  of  the 
second  element  is  strikingly  manifested  in  the  difference  between  the  various 
phases  of  the  state  of  Dreaming,  and  in  the  contrast  between  the  incoherence 
of  the  commoner  forms  of  this,  and  that  consistency  in  the  trains  of  thought 
which  generally  characterizes  the  state  of  Somnambulism ;  but  it  is  yet  more 
remarkably  displayed  in  those  forms  of  Delirium  and  Insanity  which  are  es- 
pecially characterized  by  the  complete  confusion  of  the  Intellectual  powers,  all 
previous  states  of  consciousness  being  (as  it  were)  jumbled  together,  and  the 
order  of  their  recurrence,  and  the  nature  of  the  new  combinations  which  may 
arise  out  of  them,  being  irreducible  to  any  principle  of  .orderly  sequence.  The 
influence  of  the  third  element  is  well  seen  in  those  forms  of  artificial  Reverie 
and  Somnambulism,  in  which  the  feelings  as  well  as  the  ideas  admit  of  being 
played  upon  by  external  influences ;  for  it  is  easy  to  bring  the  mind  of  the  sub- 
ject under  the  domination  of  any  particular  emotion,  by  taking  the  appropriate 
means  to  excite  it  j1  and,  so  long  as  this  may  continue,  the  language  and  actions 
most  obviously  display  its  impress.  But  it  is  in  Insanity  that  we  best  see  the 
influence  of  Emotional  states  upon  the  course  of  thought  and  of  action }  for 
here  we  find  them  supplying  impulses  to  bodily  action,  which  the  weak- 
ened Will  cannot  resist,  although  the  intellect  distinctly  apprehends  the  evil 
consequences  of  such  actions ;  or,  on  the  other  hand,  we  find  them  directing 
the  whole  course  of  mental  activity,  giving  a  wrong  color  to  all  the  ideas  which 
are  related  to  them,  and  so  fixing  the  attention  upon  the  trains  of  thought 
founded  upon  these,  that  they  come  to  attain  a  complete  domination  over  the 
mind,  and  hence  over  the  conduct,  to  which  they  supply  motives  of  such 
potency  that  the  Will  can  neither  resist  them  nor  withdraw  the  mind  from  at- 
tending to  them. 

835.  Thus,  then,  we  see  that  in  all  those  states  in  which  the  directing  power 
of  the  Will  over  the  current  of  thought  is  suspended,  the  course  of  action  is  de- 
termined by  some  dominant  ideay  which  for  the  time  has  full  possession  of  the 
mind,  and  from  which  the  individual  has  no  power  of  withdrawing  his  con- 
sciousness ;  the  motive  power  of  this  idea  being  such  as  either  impels  to  action 

antecedent  portions  of  this  inquiry,  and  especially  to  $$  804 — 6,  as  showing  to  what  ex- 
tent he  regards  the  organization  of  the  Cerebrum  as  determining  its  mode  of  psychical 
activity. 

1  We  have  seen  how  remarkably  the  emotions  may  be  played  upon,  in  the  "hypnotic" 
state,  by  muscular  associations  (827)  ;  in  the  "  biologized"  state,  it  is  often  sufficient  to  ask 
the  "  subject" — "Why  are  you  so  angry,"  "Why  are  you  so  sad,"  &c. — to  induce  these 
conditions  respectively,  the  suggestions  being  here  conveyed  verbally,  instead  of  through 
the  muscular  sense. 


812  OF   THE   FUNCTIONS   OF   THE   NERVOUS   SYSTEM. 

by  a  feeling  of  internal  necessity  (analogous  to  that  which  prompts  the  reflex 
actions  of  the  Cranio-Spinal  axis),  or  solicits  it  by  the  anticipation  of  pleasure 
in  its  result,  or  of  pain  in  abstinence  from  it.  On  the  other  hand,  the  man  in 
full  possession  of  his  psychical  capacity,  whilst  equally  amenable  with  those  in 
the  foregoing  states  to  the  influence  of  the  motive  power  of  ideas,  differs  from 
them  all  in  this  most  important  particular — that  he  has  the  power  of  refraining 
from  action  under  the  immediate  pressure  of  motives,  and  of  so  far  modifying 
their  relative  force  by  the  mode  in  which  he  contemplates  them,  that  their  ori- 
ginal balance  may  be  completely  altered ;  and  hence  his  ultimate  determination, 
whilst  still  governed  by  the  predominance  of  motives,  may  be  entirely  different 
from  that  on  which  he  would  have  acted,  if  he  had  given  way  to  his  first  im- 
pulse. For,  just  as  we  may  direct  our  Intellectual  operations  by  an  exercise  of 
Volition,  so  as  to  fix  upon  certain  ideas  only,  out  of  the  many  which  present 
themselves  to  our  consciousness,  and  to  limit  our  attention  to  certain  peculiar 
aspects  of  these  (§  823),  so  may  we  fix  our  attention  upon  any  one  or  more 
among  the  motives  which  tend  to  determine  our  action,  and  keep  these  (as  it 
were)  in  a  strong  light  before  the  mind's  eye,  whilst  by  withdrawing  our  atten- 
tion from  others,  we  virtually  throw  them  into  the  background,  just  as  we  can 
do  with  regard  to  objects  of  sensation.  And  further,  by  calling  the  Reasoning 
powers  into  operation,  and  bringing  them  to  bear  upon  the  questions  at  issue, 
so  as  to  follow  out  each  of  the  modes  of  action  that  are  before  the  mind  to  its 
probable  consequences,  the  Will  indirectly  brings  a  set  of  new  motives,  arising 
out  of  these  consequences,  before  the  judgment ;  and  these,  at  first  overlooked, 
may  become  important  elements  in  the  decision.  On  the  other  hand,  it  may  be 
that  in  thus  reasoning  out  the  probable  consequences  of  an  action,  motives 
which  at  first  presented  themselves  in  great  strength,  lose  more  or  less  of  their 
force,  and  even  become  altogether  futile. — It  is  in  these  modes  that  "  second 
thoughts"  generally  prove  to  be  best,  save  where  selfish  considerations  are 
brought  to  take  the  place  of  primary  generous  impulses ;  whilst  a  hasty  determi- 
nation often  leads  to  wrong  action,  because  all  the  motives  that  should  be  taken 
into  account  have  not  been  duly  weighed.1 

836.  Now,  if  we  examine  into  the  different  kinds  of  Motive  Powers,  which, 
under  the  permission  or  the  intentional  direction  of  the  Will,  are  the  sources 
of  Human  action,  we  shall  find  that  they  may  be  ranged  under  the  following 
heads :  (1)  Previously-acquired  Habits,  which  automatically  incite  us  to  do  as 
we  have  been  previously  accustomed  to  do  under  the  like  circumstances,  with- 
out the  idea  of  prospective  pleasure  or  pain,  or  of  right  or  wrong,  being  at  all 
present  to  our  minds.  The  formation  of  Habits,  both  of  thought  and  action, 
seems  referable  to  the  psychical  principle  of  Contiguous  Association  (§  807)  and 
to  the  physiological  principle  of  Nutritive  Assimilation  (§  591),  which,  in  regard 
to  the  operations  of  the  Cerebrum,  seem  to  be  only  different  expressions  of  the 
same  fact;  namely,  that  whatever  mode  of  activity  has  been  once  strongly  im- 
pressed on  the  organ,  this  has  a  tendency  to  perpetuate  itself.  In  so  far  as  the 
Will  yields  to  this  tendency,  instead  of  controlling  it,  the  individual  becomes 
the  slave  of  routine;  and  this  condition  is  often  very  remarkably  presented  by 

1  It  has  been  held  by  some,  that  when  a  man  is  struggling  with  a  temptation,  and  the 
motives  to  good  and  the  motives  to  evil  are  nearly  in  equilibrium,  like  weights  in  the  two 
scales  of  the  balance,  the  Will  acts  as  an  independent  preponderating  power,  like  a  hand 
pushing  down  the  scale-beam  on  one  side.  It  appears  to  the  author,  however,  to  be  much 
more  conformable  to  the  results  of  a  careful  examination  of  our  own  conduct,  to  regard 
the  will  as  imparting  an  augmented  gravity  (as  it  were)  to  the  weights  on  one  side,  by 
directing  attention  to  their  value,  'and  by  indirectly  making  additions  to  them,  in  the  man- 
ner stated  above ;  whilst  it  diminishes  the  force  of  those  on  the  other  side,  by  preventing 
the  mind  from  giving  its  attention  to  them,  and  also  (it  may  be)  by  virtually  abstracting 
some  of  them  from  the  scale. 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  813 

persons  who  are  deficient  in  Volitional  power,  as  it  is  also  among  the  lower 
animals,  from  whose  actions  we  may  derive  our  best  illustrations  of  what  Habit 
will  do,  when  it  is  not  under  the  direction  of  any  higher  principle.1  The  tend- 
ency to  habitual  action  is  so  universally  recognized  as  an  important  part  of  our 
psychical  nature,  that  Man  has  been  said  to  be  "a  bundle  of  habits."  Where 
the  habits  have  been  judiciously  formed  in  the  first  instance  the  tendency  is  an 
extremely  useful  one,  prompting  us  to  do  that  spontaneously  which  might 
otherwise  require  a  powerful  effort  of  the  Will  :2  but,  on  the  other  hand,  if  a 
bad  set  of  habits  have  grown  up  with  the  growth  of  the  individual,  or  if  a 
single  bad  tendency  be  allowed  to  become  an  habitual  spring  of  action,  a  far 
stronger  effort  of  Volition  will  be  required  to  determine  the  conduct  in  opposi- 
tion to  them.  This  is  especially  the  case,  when  the  habitual  idea  possesses  an 
Emotional  character,  and  becomes  the  source  of  desires  ;  for  the  more  frequent- 
ly these  are  yielded  to,  the  more  powerful  is  the  solicitation  they  exert. — (2). 
Emotional  states,  which  incite  us  to  particular  actions,  either  by  the  expectation 
of  gratification  in  the  act  itself  or  in  some  consequence  which  our  reason  leads 
us  to  anticipate  from  it,  or  by  the  expectation  of  pain  if  the  act  be  not  performed. 
All  those  desires  and  aversions  which  have  so  large  a  share  in  determining  our 
conduct,  come  under  this  category ;  and  to  it  must  likewise  be  referred  all  those 

1  It  is  not  uncommon  to  meet  with  Idiots,  in  whom  the  tendency  to  the  automatic  recur- 
rence of  modes  of  action  once  impressed  on  the  consciousness  is  extremely  remarkable. 
The  following  is  stated  by  Miss  Martineau  in  regard  to  a  youth  under  her  own  observa- 
tion, who,  in  consequence  of  early  injury  to  the  brain,  never  acquired  the  power  of  speech, 
or  of  understanding  the  language  of  others,  or  of  in  any  way  recognizing  other  minds ;  but 
was  at   the  same  time  strongly  affected   by  sensory  impressions.      "He  could  endure 
nothing  out  of  its  position  in  space  or  its  order  in  time.     If  any  new  thing  was  done  to  him 
at  any  minute  of  the  day,  the  same  thing  must  be  done  at  the  same  minute  every  day  thencefor- 
ward."    Thus,  although  he  disliked  personal  interference,  his  hair  and  nails  having  been 
one  day  cut  at  ten  minutes  past  eleven,  the  next  day,  and  every  day  after,  at  ten  minutes 
past  eleven,  he,  "  as  if  by  a  fate,"  brought  comb,  scissors,  and  towel ;  and  it  was  necessary  to 
cut  a  snip  of  hair  before  he  would  release  himself.     Yet  he  had  no  knowledge  whatever  of 
the  measurement  of  time  by  clocks  and  watches,  and  was  no  less  minutely  punctual  in  his 
observances  when  placed  beyond  the  reach  of  these  aids.    So  in  regard  to  form,  number,  and 
quantity,  his  actions  were  equally  methodical.    He  occupied  himself  much  in  making  paper- 
cuttings,  which  were  remarkable  for  their  symmetry.     If,  when  he  was  out  of  the  room, 
a  brick  were  taken  from  the  heap  with  which  he  amused  himself,  he  would  pass  his  hand 
over  them,  spread  them  a  little,  and  then  lament  and  wander  about  till  the  missing  one 
was  restored.    If  seven  comfits  had  once  been  put  into  his  hand,  he  would  not  rest  with  six ; 
and  if  nine  were  given,  he  would  not  touch  any  until  he  had  returned  two.     ("  Letters  on 
the  Laws  of  Man's  Nature  and  Development,"  p.  71.) — It  would  be  easy  to  adduce  multi- 
tudes of  analogous  instances  from  the  actions  of  animals,  especially  such  as  are  purposely 
trained  to  particular  habits,  by  taking  advantage  of  the  principle  of  "contiguous  associa- 
tion," which  seems  to  be  peculiarly  strong  in  Dogs,  Horses,  &c.     And  the  recurrence  of 
particular  actions  at  particular  intervals  of  time,  without  any  means  of  consciously  esti- 
mating its  passage,  or  any  incidents  that  can  suggest  the  return  of  the  period,  is  a  very 
curious  indication  of  the  degree  in  which  organic  changes  in  the  nervous  system,  once 
determined  by  a  certain  number  of  repetitions,  tend  to  perpetuate  themselves.     Thus,  a 
dog  that  has  been  accustomed  to  receive  food  at  a  certain  hour  and  place  every  day  will 
come  in  search  of  it  with  extraordinary  punctuality ;  and  the  horse  of  a  commercial  tra- 
veller, after  going  the  same  journey  a  few  times,  will  stop  at  the  houses  of  all  his  master's 
customers ;  and  when  he  has  been  pulled  up  at  a  new  point  on  one  journey,  will  spontane- 
ously stop  at  the  same  point  on  the  next — a  fact  of  which  the  author  has  personal  know- 
ledge. 

2  This  is  especially  the  case  with  regard  to  habits  of  intellectual  exertion,  which  are  in 
themselves  peculiarly  free  from  any  emotional  complication.     The  author  can  speak  from 
long  and  varied  experience,  of  the  immense  saving  of  exertion  which  arises  from  the  for- 
mation of  methodical  habits  of  mental  labor ;  which  cause  the  ordinary  routine  to  be  per- 
formed with  a  far  less  amount  of  fatigue  than  would  be  required  on  a  more  desultory  sys- 
tem.    Even  here,  however,  care  should  be  taken  to  avoid  allowing  one's-self  to  be  as  much 
the  slave  of  habits,  that  all  mental  labor,  save  that  which  is  undertaken  at  a  particular 
time,  or  in  a  particular  place,  becomes  difficult  and  wearisome. 


814  OF   THE    FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

considerations  which  are  simply  prudential,  these  usually  having  reference  to 
the  remoter  effects  which  our  actions  are  likely  to  have  upon  our  own  welfare  or 
upon  that  of  others,  and  thus  bringing  before  the  mind,  as  elements  in  its  de- 
termination, certain  additional  objects  of  desire  or  aversion. — (3)  Notions  of 
Right  and  of  Duty,  which,  so  far  as  they  attach  themselves  to  our  actions,  give 
them  a  moral  and  religious  character.  These  may  act  simply  as  ideas,  whose 
coercive  power  depends  upon  the  intensity  with  which  they  are  brought  before 
the  mind ;  but  they  obtain  a  much  stronger  influence,  when  they  acquire  an 
Emotional  character  from  the  association  of  the  feeling  of  desire  with  the  idea 
of  obligation  ;  that  is,  when  we  feel  a  wish  to  do  that  which  we  are  conscious 
we  ought  to  do.  This  association  is  one  which  it  is  peculiarly  within  the  ca- 
pability of  the  Will  to  cherish  and  strengthen.  And  still  more  powerful  is 
the  operation  of  these  combined  motives,  when  a  constant  habit  of  acting  upon 
them  has  been  formed ;  for  the  strongest  desires  are  then  immediately  repress- 
ed, the  strongest  aversions  cease  to  exert  an  influence,  when  once  the  question  is 
looked  at  in  its  moral  aspect,  and  a  clear  perception  has  been  attained  of  its 
right  and  its  wrong  side.1 

837.  It  has  been  usually  considered  by  Moralists  and  Theologians  that  Con- 
science^ or  the  Sense  of  Duty,  is  an  autocratic  faculty,  which  unmistakably 
dictates  what  is  right  in  each  individual  case,  and  which  should  consequently  be 
unhesitatingly  obeyed  as  the  supreme  and  unerring  guide.  Now  this  view  of 
the  case  is  attended  with  practical  difficulties,  which  make  it  surprising  that  it 
can  ever  have  been  entertained.  For  it  must  be  obvious  to  every  one  who 
carefully  considers  the  matter,  that,  whilst  a  notion  of  right  and  wrong,  attach- 
ing itself  to  certain  actions,  is  as  much  a  part  of  the  moral  nature  of  every  in- 
dividual, as  the  feeling  of  pleasure  or  pain  attaching  itself  to  certain  states  of 
consciousness  is  of  his  sensational  nature,  yet  the  determination  of  what  is  right 
and  what  is  wrong  is  a  matter  in  great  degree  dependent  upon  education,  habits 
of  thought,  conventional  associations,  &c. ;  so  that  the  moral  standard  of  no  two 
men  shall  be  precisely  alike,  and  the  moral  standards  of  men  brought  up  under 
entirely  different  circumstances  shall  be  of  the  most  opposite  nature.3  So,  whilst 

1  The  difference  between  the  habitual,  the  prudential,  and  the  moral  aspects  of  the  very 
same  action,  may  be  made  apparent  by  a  very  simple  illustration. — We  will  suppose  that 
a  man  has  been  accustomed  to  take  a  ride  every  day  at  a  particular  hour ;  his  whole 
nature  so  accommodates  itself  to  the  habit,  that  he  feels  both  mentally  and  physically  uncom- 
fortable at  any  interruption  to  the  usual  rhythm.    But  suppose  that,  just  as  the  appointed 
hour  comes  round,  the  sky  becomes  overcast,  threatening  the  rider  with  a  drenching  if  he 
perseveres  in  his  attention,  his  decision  will  then  be  founded  on  a  prudential  considera- 
tion of  the  relative  probabilities  of  his  escaping  or  of  his  being  exposed  to  the  shower,  and 
of  how  far  the  enjoyment  he  may  derive  from  his  ride  is  likely  to  be  replaced  by  the  dis- 
comfort of  a  thorough  wetting.     But  suppose,  further,  that,  instead  of  taking  a  mere  plea- 
sure ride,  a  medical  man  is  about  to  set  forth  on  a  professional  visit  to  a  patient  whose 
condition  requires  his  aid  ;  a  new  motive  is  thus  introduced,  which  alters  the  condition  of 
the  whole  question,  making  it  no  longer  one  of  prudence  only,  but  one  of  morality.     An- 
other motive  which  should  give  the  question  a  moral  aspect,  would  be  consideration  for 
himself,  and  the  risk  of  life  or  health  he  might  run ;  this  should  be  decisive  where  the  mo- 
tive which  impels  him  to  the  act  in  question  is  merely  that  of  self-gratification ;  but  if  it 
bring  into  antagonism  his  duty  to  his  patient  and  his  desire  to  benefit  him,  and  on  the 
other  hand  his  duty  to  himself  and  his  regard  for  the  ulterior  welfare  of  those  who  may 
be  immediately  dependent  upon  him,  the  question  has  its  right  and  its  wrong  aspect  on 
both  sides,  and  the  right  may  only  be  determined  after  a  careful  balance  of  probabilities. 
Such  moral  conflicts  are  continually  occurring  amongst  medical  practitioners  in  regard  to 
exposure  to  the  severity  of  the  weather,  to  dangerous  infection,  or  to  risks  of  other  kinds ; 
and  the  decision  will  mainly  depend  upon  the  previously  formed  habits,  on  the  one  hand 
of  disregarding  all  considerations  connected  with  self,  on  the  other  of  attaching  special 
weight  to  them. 

2  Without  having  recourse  to  the  strange  estimates  of  right  and  wrong  which  prevail 
amongst  Savage  nations,  for  an  illustration  of  this  position,  it  may  be  sufficient  to  compare 
the  different  views  conscientiously  entertained  on  the  question  of  Slavery,  by  high-minded, 
estimable,  and  Christian  men  and  women  in  different  parts  of  the  American  Union. 


THE    CEREBRUM,    AND   ITS   FUNCTIONS.  815 

the  notion  of  a  (rod  sustaining  any  direct  relation  to  us,  involves  the  notion  of 
Duty,  which  attaches  itself  to  all  actions  with  which  he  can  be  considered  as 
having  any  concern,  the  dictates  of  this  sense  will  vary  with  the  ideas  enter- 
tained respecting  the  character  and  requirements  of  the  Deity ;  and  actions  may 
be  sincerely  regarded  as  an  acceptable 'sacrifice  by  one  class  of  religionists,  which 
are  loathed  as  barbarous  and  detestable  by  another.  Moreover,  in  what  have 
been  designated  as  "  cases  of  conscience,"  the  most  enlightened  Moralist  may 
have  a  difficulty  in  deciding  what  is  the  right  course  of  action,  simply  because 
the  moral  sense  finds  so  much  to  approve  on  both  sides  that  it  cannot  assign  a 
preponderance  to  either.  And  the  same  difficulty  attends  the  determination  of 
Duty,  in  many  peculiar  contingencies  j  each  of  two  or  more  possible  modes  of 
action  being  recommended  by  its  conformity  to  the  divine  law  on  certain  points 
whilst  it  seems  opposed  to  it  on  others.  Thus,  individuals  in  whose  characters 
the  love  of  truth  and  of  justice  and  the  benevolent  affections  are  the  prominent 
features,  and  who  would  shrink  with  horror  from  any  violation  of  these  princi- 
ples of  action  for  any  selfish  purpose  whatever,  are  sorely  perplexed  when  they 
are  brought  into  collision  with  each  other ;  a  strong  motive  to  tell  a  falsehood 
being  presented  by  the  desire  to  protect  a  defenceless  fellow-creature  from  un- 
merited oppression  or  death.1 — If,  then,  neither  the  Moral  Sense  nor  the  Sense 
of  Religious  Duty  affords  a  clear  and  unvarying  rule  of  action  in  each  individual 
case,  it  is  evident  that  the  determination  of  what  is  right  and  wrong  must  be  a 
matter  of  judgment ;  the  rule  of  Moral  action  being  based  on  a  comparison  of 
the  relative  nobility  of  the  motives  which  impel  us  to  either  course,  and  being 
decided  by  the  preference  which  is  accorded  to  one  motive  or  combination  of 
motives  above  another.2  If  it  be  asked  how  are  the  relative  values  of  these 

1  Thus,  if  a  man,  who  might  be  urged  to  conceal  a  fugitive  slave  near  the  Canadian  front- 
ier, were  to  refuse  to  do  so  merely  on  the  fear  of  unpleasant  consequences  to  himself, 
he  would  be  justly  branded  with  the  character  of  a  cold-hearted  coward;  but  if  his  refusal 
should  proceed  from  the  conviction  that  the  divine  law  requires  the  preference  of  rigid 
truthfulness  over  every  other  motive,  and  that,  by  concealing  the  suppliant  he  should  be 
forced  into  a  violation  of  that  law,  he  cannot  be  blamed  even  by  those  who  believe  that 
the  law  of  compassion  written  upon  our  hearts  is  at  least  equally  imperative. — Similar 
difficulties  beset  the  upholders  of  the  non-resistance  creed,  which  teaches  that  love  is  the 
all-powerful  principle  in  the  moral  world,  and  that  it  should  entirely  supersede  all  those  im- 
pulses of  our  nature  which  lead  us  to  oppose  force  to  force,  and  to  resist  an  unjust  and  unpro- 
voked assault.    Here,  again,  we  might  readily  understand  and  sympathize  with  those  who 
consider  that  the  fear  of  personal  suffering  does  not  warrant  our  doing  a  severe  injury  to 
another  in  warding  off  a  threatened  attack;  but  when  the  question  comes  to  be,  not  of 
se//-defence,  but  of  protection  to  others  who  are  helpless  dependents  upon  our  succor, 
and  who  are  bound  to  us  by  the  closest  ties  of  natural  affection,  we  feel  that  the  com- 
parative nobility  of  the  latter  motive  warrants  actions  which  our  individual  peril  might 
scarcely  justify. 

2  This  view  of  the  nature  of  Conscience  will  be  found  more  fully  developed  in  the 
"Prospective  Review"  for  November  1845,  pp.   587-9. — "Every  moral  judgment,"  it  is 
well  remarked  by  the  reviewer,  "is  relative,-  and  involves  a  comparison  of  (at  least)  two 
terms.     When  we  praise  what  has  been  done,  it  is  with  the  coexistent  conception  of  some- 
thing else  that  might  have  been  done ;  and  when  we  resolved  on  a  course  as  right,  it  is  to 
the  exclusion  of  some  other  that  is  wrong."     This  is  why  we  cannot  attach  any  moral 
character  to  the  actions  of  animals  that  are  performed  under  the  direction  of  a  blind 
undesigning  instinct,  leaving  them  no  choice  between  one  course  and  another ;  nor  to  those 
which  are  executed  by  human  beings,  even  when  possessed  of  their  full  intelligence, 
under  the  domination  of  impulses  which  they  have  it  not  in  their  power  to  restrain ;  nor, 
again,  to  those  performed  by  individuals  whose  moral  sense  has  either  never  been  awak- 
ened, or  has  been  so  completely  misdirected  by  early  education,  that  their  standard  of 
right  and  wrong  is  altogether  opposite  to  that  which  the  enlightened  conscience  of  mankind 
agrees  in  adopting.    But,  although  there  are  doubtless  many  cases  in  which  criminal  actions 
are  committed  under  the  impulse  of  passions  (such  as  anger,  lust,  &c.)  which  the  individual 
has  not  at  the  moment  the  power  to  control,  and  although  he  must  be  absolved  from  moral 
responsibility  quoad  the  immediate  motives  of  those  particular  actions,  yet  these  motives 


816  OF   THE   FUNCTIONS    OF  THE   NERVOUS    SYSTEM. 

motives  to  be  decided,  the  answer  must  be  sought  in  the  general  consciousness 
of  Mankind,  which  is  found  to  be  more  and  more  accordant  in  this  respect,  the 
more  faithfully  it  is  interpreted,  the  more  habitually  it  is  acted  on,  and  the 
more  the  whole  intelligence  is  expanded  and  enlightened.  It  is  this  tendency 
towards  universal  agreement  which  shows  that  there  is  really  as  good  a  founda- 
tion for  Moral  science  in  the  psychical  nature  of  Man,  as  there  is  for  that  of 
Music  in  the  pleasure  which  he  derives  from  certain  combinations  and  succes- 
sions of  sounds.  So,  again,  the  more  elevated  are  the  religious  ideas  of  Man- 
kind in  regard  to  the  character  and  will  of  the  Deity,  the  more  will  they  ap- 
proach to  a  general  accordance  in  regard  to  what  constitutes  Religious  Duty  ; 
and  the  complete  coincidence  which  exists  between  the  dictates  of  the  Christian 
law  and  the  highest  principles  of  pure  Morality  prevents  one  set  of  motives 
from  ever  coming  into  antagonism  with  the  other.  The  Conscience  of  the  reli- 
gious man,  indeed,  may  be  said  to  be  the  resultant  of  his  Moral  sense,  combined 
with  the  idea  of  Duty  which  arises  out  of  his  sense  of  relation  to  the  Deity. 
With  the  former  are  closely  associated  all  those  emotions  and  propensities 
which  render  him  considerate  of  the  welfare  of  his  fellow-men  as  of  his  own ; 
and  with  the  notion  of  duty  to  God  are  closely  united  the  desire  of  His  favor, 
the  fear  of  his  displeasure,  the  aspiration  after  His  perfection,  all  which  act 
like  other  motives  in  deciding  the  Will.  Their  relative  force  on  any  occasion, 
as  compared  with  that  of  the  lower  propensities  and  sensual  desires,  greatly 
depends  on  the  degree  in  which  they  are  habitually  brought  to  influence  the 
mind ;  and  it  is  in  its  power  of  fixing  the  contemplation  on  those  higher  con- 
siderations which  ought  to  be  paramount  to  all  others,  and  of  withdrawing  it 
from  the  lower,  that  the  Will  has  the  chief  influence  in  the  direction  of  the 
conduct  according  to  the  dictates  of  Virtue. 

838.  From  the  general  survey  which  we  have  now  taken  of  the  phenomena 
of  Mind,  it  seems  to  be  the  obvious  conclusion  that  these  phenomena  essentially 
consist  in  a  succession  of  states  of  consciousness  ;  and  that  this  succession  takes 
place,  like  the  phenomena  of  the  Material  Universe,  under  certain  determinate 
conditions.  We  have  seen  that,  in  those  actions  of  the  Nervous  system  (as  of 
other  parts  of  the  body)  in  which  the  Will  is  not  concerned,  we  have  simply  to 
consider  the  two  elements  of  which  we  take  account  in  all  scientific  inquiry ; 
namely,  the  force  that  operates,  and  the  organized  structure  on  and  through 
which  it  operates — in  other  words,  the  dynamical  agency,  and  the  material  con- 
ditions. And  if  we  could  imagine  a  being  to  grow  up  from  infancy  to  maturity, 
with  a  mind  in  the  state  of  that  of  a  "  biologized"  subject  (§  825),  we  should 
see  that  it  would  be  strictly  correct  to  speak  of  his  character  as  formed  for  him 
and  not  by  him ;  all  his  thoughts,  feelings,  and  actions  being  but  the  reflex  of 
his  own  nature  upon  the  impressions  made  upon  it ;  and  that  nature  being 
determined  in  part  by  original  constitution,  and  in  part  by  the  mode  in  which 
it  is  habitually  called  into  action. — This  last  condition  is  one  that  is  peculiar  to 
a  living  and  growing  organism;  and  it  is  one  which  cannot  be  too  strongly  or 
too  constantly  kept  in  mind.  A  mere  inorganic  substance  reacts  in  precisely 
the  same  mode  to  mechanical,  chemical,  electrical,  or  other  agencies,  how- 
ever frequently  these  are  brought  to  bear  upon  it,  provided  it  has  been  restored 
to  its  original  condition ;  thus  water  may  be  turned  into  steam,  the  steam  con- 
densed into  water,  and  the  water  raised  into  steam  again,  any  number  of  times, 
without  the  slightest  variation  in  the  effects  of  the  heat  and  cold  which  are. the 
efficient  causes  of  the  change.  But  every  kind  of  activity  peculiar  to  a  living  body, 

too  frequently  derive  all  their  force  from  the  habit  of  yielding  to  their  promptings  in 
lesser  matters,  which  gradually  gives  them  a  dominance,  such  as  the  Will  (weakened  by 
want  of  exercise  in  the  habit  of  self-restraint)  is  unable  to  resist.  Hence  the  criminal 
action  is  to  be  regarded  as  but  the  expression  of  a  long  previous  course  of  criminal  thought, 
for  which,  in  so  far  as  he  could  have  otherwise  directed  it,  the  individual  may  legitimately 
be  held  responsible. 


THE   CEREBRUM,   AND   ITS   FUNCTIONS.  817 

involves  (as  has  been  repeatedly  shown)  a  change  of  structure;  and  the  formation 
of  the  newly  generated  tissue  receives  such  an  influence  from  the  conditions  under 
which  it  originates,  that  all  its  subsequent  activity  displays  their  impress. — This 
view,  indeed,  must  be  extended  to  that  remarkable  hereditary  transmission  of 
psychical  character,  which  presents  itself  under  circumstances  that  entirely  forbid 
our  attributing  it  to  any  agency  that  can  operate  subsequently  to  birth,  and  which 
it  would  seem  impossible  to  account  for  on  any  other  hypothesis  than  that  the 
formative  capacity  of  the  germ  determines  the  subsequent  development  of  the 
Brain,  as  of  other  parts  of  the  body,  and  (through  this)  its  mode  of  activity,  in 
accordance  with  the  influences  under  which  that  germ  was  first  impregnated.  And 
thus  what  we  speak  of  as  the  "  original  constitution"  of  each  individual,  is  in 
great  part  (if  not  entirely)  determined  by  the  conditions,  dynamical  and  material, 
of  the  parent-organisms ;  a  convincing  proof  of  which  general  fact  is  afforded  by 
a  careful  examination  of  the  parental  constitution  and  habits,  in  a  large  propor- 
tion of  cases  of  Idiocy.1  Whatever  may  be  the  congenital  constitution,  how- 
ever, there  can  be  no  question  that  this  is  liable  to  great  modification  from  ex- 
ternal influences,  both  such  as  directly  affect  its  physical  conditions,  and  such 
as  operate  through  the  consciousness,  in  determining  the  course  of  thought  and 
feeling,  before  the  individual  has  acquired  any  self-determining  power.  Of  this 
influence  of  physical  agencies,  we  have  a  typical  example  in  the  phenomena  of 
Cretinism ;  since,  although  the  conditions  under  which  that  state  is  developed 
have  not  yet  been  precisely  determined,  no  one  can  reasonably  doubt  that  they 
are  such  as  act  in  the  first  instance  in  modifying  the  nutrition  and  activity  of 
the  bodily  organism  in  general,  and  of  the  Nervous  system  in  particular. 

839.  From  the  time  when  the  Human  being  first  becomes  conscious  that  he 
has  a  power  within  himself  of  determining  the  succession  of  his  mental  states, 
from  that  time  does  he  begin  to  be  a  free  agent ;  and  in  proportion  as  he  exerts 
that  power,  does  he  emancipate  himself  from  the  domination  of  his  constitutional 
or  automatic  tendencies.  It  is  a  principle  now  recognized  by  all  the  most  enlight- 
ened educators,  that  the  development  of  this  power  of  self-control  ought  to  be 
the  object  of  all  nursery  discipline  j  and  the  process  of  its  acquirement  is  very 
gradual.  When  an  infant  is  excited  to  a  fit  of  passion  by  some  unpleasant  sen- 
sation, its  nurse  attempts  to  restore  its  equanimity  by  presenting  some  new 
object  to  its  attention,  so  that  the  more  recent  and  vivid  pleasurable  impression 
may  efface  the  sense  of  past  uneasiness.  As  the  infant  grows  into  childhood, 
the  judicious  parent  no  longer  trusts  to  mere  sensory  impressions  for  the  diver- 
sion of  the  passionate  excitement,  but  calls  up  in  its  mind  such  ideas  and  feel- 
ings as  it  is  capable  of  appreciating,  and  endeavors  to  keep  the  attention  fixed 
upon  these,  until  the  violence  of  the  emotion  has  subsided ;  and  recourse  is  had 
to  the  same  process,  whenever  it  is  desired  to  check  any  tendency  to  action 
which  depends  upon  the  selfish  propensities — appeal  being  always  made  to  the 
highest  motives  which  the  child  is  capable  of  recognizing,  and  punishment  being 
only  had  recourse  to  for  the  purpose  of  supplying  an  additional  set  of  motives 
when  all  others  fail.  For  a  time,  this  process  of  external  suggestion  may  need 
to  be  continually  repeated,  where  there  are  strong  impulses  whose  unworthy 
character  calls  for  repression ;  but  if  it  be  judiciously  adapted  and  consistently 
persevered  in,  a  very  slight  suggestion  serves  to  recall  the  superior  motives  to 
the  conflict.  And  in  further  space,  the  child  comes  to  feel  that  he  has  himself 
the  power  of  recalling  them,  and  of  controlling  his  urgent  impulses  to  immediate 
action.  The  power  of  self-control,  thus  usually  acquired  in  the  first  instance 


A  most  valuable  collection  of  data  on  this  subject  is  afforded  by  Dr.  Howe's  admirable 
tort 

ined 
52 


"Report  on  Idiocy"  made  to  the  Legislature  of  Massachusetts,  of  which  an  abstract  is 
contained  in  the  "American  Journal  of  the  Medical  Sciences,"  April,  1849. 


818  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

in  regard  to  those  impulses  which  directly  determine  the  conduct,  gradually 
extends  itself  to  the  habitual  succession  of  the  thoughts  ;  and  in  proportion  as 
this  is  brought  under  the  direction  of  the  Will,  does  the  individual  become  capable 
of  forming  his  own  character,  and  therefore  truly  responsible  for  his  actions. — It 
must  not  be  forgotten,  however,  that  the  power  of  self-control  may  be  turned  to  a 
bad  as  well  as  to  a  good  account ;  and  that  the  value  of  its  results  will  entirely 
depend  upon  the  direction  in  which  it  is  employed.  The  thoughts  may  be  so  de- 
terminate ly  drawn  away  from  the  higher  class  of  motives,  the  suggestions  of  con- 
science so  habitually  disregarded,  and  the  whole  attention  so  completely  fixed 
upon  the  gratification  of  selfish  or  malevolent  propensities,  that  the  Human 
nature  acquires  far  more  of  the  Satanic  than  of  the  Divine  character ;  the  high- 
est development  of  this  type  (if  the  term  may  be  permitted)  being  displayed 
by  those  who  use  their  power  of  self-control  for  the  purposes  of  hypocrisy  and 
dissimulation,  and  cover  the  most  malignant  designs  under  the  veil  of  friendship. 
Such  men  (whose  portraiture  is  presented  by  our  great  Dramatist  in  the  cha- 
racter of  lago)  show  us  to  what  evil  account  the  highest  intellect  and  the  most 
powerful  will  may  be  turned,  when  directed  by  the  baser  class  of  motives ;  and 
we  cannot  but  feel  that  they  are  far  more  degraded  in  the  moral  scale,  than 
those  who,  having  never  learned  to  control  their  animal  propensities,  and  being 
unconscious  of  the  very  existence  of  a  higher  nature  within  themselves,  simply 
obey  the  promptings  of  their  automatic  impulses,  and  are  rather  to  be  consid- 
ered as  ill-conditioned  automata,  than  as  vicious  men.  Of  this  latter  class, 
some,  from  original  constitution  and  early  influences  of  the  most  degrading  kind, 
seem  altogether  destitute  of  anything  but  a  brutal  nature ;  such  ought  to  be 
treated  as  irresponsible  beings,  and,  as  such,  restrained  by  external  coercion 
from  doing  injury  to  society.  But  this  class  is  small  in  proportion  to  that  of 
individuals  who  act  viciously,  simply  because  they  have  never  been  led  to  know 
that  any  other  course  is  open  to  them,  or  to  feel  any  motives  that  might  give 
them  a  different  impulse.  With  these,  the  object  should  rather  be  to  awaken 
the  higher  parts  of  the  moral  nature,  "  to  find  out  the  holy  spot  in  every  child's 
heart,"  and  to  develop  habits  of  self-control  in  the  manner  just  described,  than 
to  subjugate  by  external  restraint ;  and  the  success  which  has  attended  this 
method,  in  the  hands  of  those  who  have  judiciously  applied  it,  is  sufficient  evi- 
dence of  its  superiority ;  many  of  the  most  apparently  debased  natures  having 
been  thus  elevated  to  a  grade  which  it  seemed  at  first  impossible  they  could 
ever  attain.  From  the  Satanic,  or  positively  and  wilfully  evil  type  of  Human 
nature,  in  which  the  highest  powers  are  turned  to  the  worst  account,  we  are 
thus  conducted  through  the  brutal  or  negatively  evil  type,  towards  that  higher 
aspect  of  Humanity,  which  is  presented  by  those  who  habitually  keep  before 
them  the  Divine  ideal,  and  who  steadily  endeavor  to  bring  their  whole  nature 
into  conformity  with  it.  This  is  not  to  be  effected  by  dwelling  exclusively  on 
any  one  set  of  the  motives  already  referred  to,  as  those  which  the  truly  religious 
man  keeps  before  his  mind.  Even  the  idea  of  Duty,  operating  alone,  tends  to 
reduce  the  individual  to  the  subservience  of  a  slave,  rather  than  to  induce  in 
him  that  true  mastery  over  himself  which  consists  in  such  a  regulation  of  his 
emotions  and  propensities  that  his  course  of  duty  becomes  the  spontaneous  ex- 
pression of  his  own  higher  nature ;  but  it  is  a  most  powerful  aid  in  the  acquire- 
ment of  that  regulation,  by  the  fixation  of  the  thoughts  and  affections  on 
"  things  on  high,"  which  is  the  best  means  of  detaching  them  from  all  that  is 
earthly  and  debasing.  It  is  by  the  assimilation,  rather  than  by  the  subjugation 
of  the  Human  Will  to  the  Divine,  that  Man  is  really  lifted  towards  God ;  and 
in  proportion  as  this  assimilation  has  been  effected,  does  it  manifest  itself  in  the 
life  and  conduct ;  so  that  even  the  lowliest  actions  become  holy  ministrations 
in  a  temple  consecrated  by  the  felt  presence  of  the  Divinity.  Such  was  the 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  819 

life  of  the  Saviour ;  towards  that  standard  it  is  for  the  Christian  disciple  to 
aspire.1 

840.  Of  Sleep. — It  is  a  peculiar  feature  in  the  physiology  of  the  Cerebral 
and  Sensorial  Ganglia,  that   their  activity  undergoes  a  periodical  suspension, 
more  or  less  complete ;  the  necessity  for  this  suspension  arising  out  of  the  fact 
that  the  exercise  of  their  functions  is  in  itself  destructive  to  their  substance,  so 
that,  if  this  be  not  replaced  by  nutritive  regeneration,  they  speedily  become  in- 
capacitated for  further  use.     In  ordinary  profound  sleep,  there   is  a  state  of 
complete  unconsciousness,  so  far  as   external  phenomena  are  concerned  ;   no 
ordinary  impressions  upon  the  organs  of  sense  being  either  felt  or  perceived ; 
although  an  extraordinary  impression,  or  even  an  habitual  one  upon  which  the 
attention  has  been  previously  fixed  as  that  at  which  the  slumberer  is  to  awake 
himself  (§  843),  occasions  a  renewal  of  sensorial  activity.     It  is  in  this  capability 
of  being  aroused  by  external  impressions,  that  the  chief  difference  lies  between 
Sleep  and  the  abnormal  condition  of  Coma,  whether  this  arise  from  the  influence 
of  pressure  or  effusion  within  the  cranium,  or  be  consequent  upon  the  poisoning 
of  the  blood  by  narcotic  substances,  or  follow  a  previous  state  of  abnormal  ac- 
tivity of  the  brain,  such  as  delirium.     Between  these  two  conditions,  however, 
every  gradation  may  be  seen;  as  in   the  gradually   increasing  torpor  which 
results  from  slow  effusion  within  the  cranium,  the  gradual  loss  of  susceptibility 
to  external  impressions  which  is  observed  after  an  over-dose  of  a  narcotic,  and 
the  intensification  of  ordinary  sleep  which  is  consequent  upon  extreme  previous 
fatigue.     It  is  a  matter  of  doubt,  however,  whether  the  suspension  of  sensorial 
consciousness  is  equally  complete  as  regards  internal  or  Cerebral  changes ;  for 
some  are  of  opinion  that,  even  in  the  most  profound  sleep,  we  still  dream,  al- 
though we  may  not  remember  our  dreams  ;  whilst  others  (and  among  these  the 
Author  would  rank  himself)  consider  that  dreaming  is  a  mark  of  imperfect 
sleep,  and  that,  in  profound  ordinary  sleep,  the  Cerebrum,  as  well  as  the  Sensory 
Ganglia,  is  in  a  state  of  complete  functional  inactivity.     When  dreaming  takes 
place,  there  is  usually  a  less  complete  exclusion  of  sensory  impressions,  although 
the  perceptive  consciousness  may  be  entirely  suspended  ;  so  that  the  course  of 
the  dream  may  be  influenced  by  them,  although  the  mind  is  not  conscious  of 
them  as  such  (§  828).     If  this  be  the  true  account  of  the  case,  we  may  con- 
sider that,  in  profound  Sleep,  the  functional  activity  of  the  Cerebrum  and  of 
the  Sensory  Ganglia  is  alike  suspended ;  that  in  Dreaming,  the  Cerebrum  is 
partially  active,  and  that  the  Sensoriurn  is  in  such  a  condition  of  recipience  fcr 
Cerebral  impressions  that  the  mind  becomes  directly  conscious  of  them,  whilst 
it  only  becomes  conscious  of  impressions  made  upon  the  Organs  of  Sense,  after 
their  influence  has  been  transmitted  through  it  to  the  Cerebrum,  and  has  been, 
as  it  were,  reflected  back  by  that  organ.     It  is,  in  fact,  by  their  influence  upon 
the  current  of  ideas,  and  not  by  their  power  of  exciting  sensations,  that  we  re- 
cognize their  operation  under  such  circumstances. 

841.  The  state  of  Sleep  is  one  to  which  there  is  beyond  doubt  a  periodical 
tendency ;  for,  when  the  waking  activity  has  continued  for  a  considerable  pro- 
portion of  the  twenty-four  hours,  a  sense  of  fatigue  is  usually  experienced,  which 
indicates  that  the  brain  requires  repose;  and  it  is  only  under  some  very  strong 
physical  or  moral  stimulus,  that  the  mental  energy  can  be  sustained  through  the 
whole  cycle.     In  fact,  unless  some  decidedly  abnormal  condition  of  the  Cere- 

'  The  careful  study  of  the  Epistles  of  St.  Paul  will  show  this  to  be  the  dominant  idea  of 
this  Apostle's  teachings.  Under  the  name  of  "  the  law,"  he  refers  to  the  spirit  of  bondage 
or  external  coercion,  which  "was  the  schoolmaster  to  bring  us  to  Christ;"  whilst  under  the 
designation  of  "the  Gospel"  he  obviously  desires  to  express  that  spirit  of  freedom  or  in- 
ternal spontaneity  which  is  the  source  of  all  that  is  truly  noble  in  the  Christian  character. 


820  OF   THE   FUNCTIONS   OF   THE    NERVOUS    SYSTEM. 

brum  be  induced  by  the  protraction  of  its  functional  activity,  Sleep  will  at  last 
supervene,  from  the  absolute  inability  of  the  organ  to  sustain  any  futher  demands 
upon  its  energy,  even  in  the  midst  of  opposing  influences  of  the  most  powerful 
nature.1  That  the  strongest  voluntary  determination  to  remain  awake  is  forced 
to  give  way  to  Sleep,  when  this  is  required  by  the  exhaustion  of  nervous  power, 
must  be  within  the  experience  of  every  one ;  and  the  only  way  in  which  the 
Will  can  even  retard  its  access,  is  by  determinately  fixing  the  consciousness  upon 
some  definite  object,  and  resisting  every  tendency  in  the  thoughts  to  wander 
from  this.  It  does  not  appear  to  be  of  any  consequence,  whether  this  exhaustion 
be  produced  by  the  active  exercise  of  volition,  reflection,  emotion,  or  simple 
sensation  ;  still  we  find  that  the  volitional  direction  of  the  thoughts,  in  a  course 
different  from  that  in  which  they  tend  spontaneously  to  flow,  is  attended  with 
far  more  effort  than  the  automatic  activity  of  the  mind  (§  823);  whilst,  on  the 
other  hand,  the  excess  of  automatic  activity,  whether  as  regards  the  intellectual 
operations  or  emotional  excitement,  tends  to  prevent  sleep.  This  is  particularly 
the  case  when  the  feelings  are  strongly  interested ;  thus,  the  strong  desire  to 
work  out  a  result,  or  to  complete  the  survey  of  a  subject,  is  often  sufficient  to 
keep  up  the  intellectual  activity  as  long  as  may  be  requisite  (a  state  of  restless- 
ness, however,  being  often  induced,  which  prevents  the  access  of  sleep  for  some 
time  longer);  so,  again,  anxiety  or  distress  is  a  most  frequent  cause  of  wakeful- 
ness  ;  and  it  is  generally  to  be  observed  that  the  state  of  suspense  is  more  opposed 
to  the  access  of  sleep  than  the  greatest  joy  or  the  direst  calamity  when  certainty 
has  been  attained.2  But  although  an  excess  of  automatic  activity  is  opposed,  so 
long  as  it  continues,  to  the  access  of  sleep,  yet  it  cannot  be  long  protracted  with- 
out occasioning  an  extreme  exhaustion  of  nervous  power,  which  necessitates  a 
long  period  of  tranquillity  for  its  complete  restoration. — But  whilst  the  necessity 
for  sleep  arises  out  of  the  state  of  the  nervous  system  itself,  there  are  certain 
external  conditions  which  favor  its  access;  and  these,  in  common  parlance,  are 
termed  its  predisposing  causes.  Among  the  most  powerful  of  these  is  the 
absence  of  sensorial  impressions;  thus,  darkness  and  silence  usually  promote  re- 
pose ;  and  the  cessation  of  the  sense  of  muscular  effort,  which  takes  place  when 
we  assume  a  position  that  is  sustained  without  it,  is  no  less  conducive  to  slumber. 
There  are  cases,  however,  in  which  the  continuance  of  an  accustomed  sound  is 
necessary,  instead  of  positive  silence,  the  cessation  of  the  sound  being  a  com- 
plete preventive  of  sleep  ;  thus  it  happens  that  persons  living  in  the  neighbor- 
hood of  the  noisiest  mills  or  forges  cannot  readily  sleep  elsewhere.  Such  cases 
are  referable,  either  to  the  influence  of  habit,  which  causes  the  attention  of  the 

1  Thus  it  is  on  record,  that  during  the  heat  of  the  battle  of  the  Nile,  some  of  the  over- 
fatigued  boys  fell  asleep  upon  the  deck ;  and  during  the  recent  attack  upon  Rangoon,  the 
Captain  of  one  of  the  war-steamers  most  actively  engaged,  worn  out  by  the  excess  of  con- 
tinued mental  tension,  fell  asleep  and  remained  perfectly  unconscious  for  two  hours,  within 
a  yard  of  one  of  his  largest  guns,  which  was  being  worked  energetically  during  the  whole 
period.     So  even  the  severest  bodily  pain  yields  before  the  imperative  demand  occasioned 
by  the  continued  exhaustion  of  the  powers  of  the  sensorial  centres ;  thus  Damiens  slept 
upon  the  rack,  during  the  intervals  of  his  cruel  sufferings  ;   the  North  American  Indian  at 
the  stake  of  torture  will  go  to  sleep  on  the  least  remission  of  agony,  and  will  slumber  until 
the  fire  is  applied  to  awaken  him ;  and  the  medical  practitioner  has  frequent  illustrations 
of  the  same  fact.     That  the  continued  demand  for  muscular  activity  is  not  incompatible 
with  the  access  of  sleep,  is  obvious  from  what  has  been  already  said  of  the  persistence  of 
the  automatic  movements  in  that  condition  (g  726) :  it  is  well  known  that,  previously  to 
the  shortening  of  the  hours  of  work,  factory  children  frequently  fell  asleep  whilst  attend- 
ing to  their  machines,  although  well  aware  that  they  should  incur  severe  punishment  by 
doing  so. 

2  Thus  it  is  a  common  observation  that  criminals  under  sentence  of  death  sleep  badly 
so  long  as  they  entertain  any  hopes  of  a  reprieve  ;  but  as  soon  as  they  are  satisfied  that 
their  death  is  inevitable,  they  usually  sleep  more  soundly,  and  this  even  on  the  very  last 
night  of  their  lives. 


THE   CEREBRUM,    AND    ITS   FUNCTIONS.  821 

individual  to  be  more  attracted  by  the  suspension  of  the  sound  than  by  its  con- 
tinuance ;  or  to  the  fact  that  the  monotonous  repetition  of  sensorial  impressions  is 
often  more  favorable  to  sleep  than  their  complete  absence.  Thus  it  is  within  the 
experience  of  every  one  that  the  droning  voice  of  a  heavy  reader  on  a  dull  sub- 
ject is  often  a  most  effectual  hypnotic;  in  like  manner,  the  ripple  of  the  calm 
ocean  on  the  shore,  the  sound  of  a  distant  waterfall,  the  rustling  of  foliage, 
the  hum  of  bees,  and  similar  impressions  upon  the  auditory  sense,  are  usually 
favorable  to  sleep ;  and  the  muscular  and  tactile  senses  may  be  in  like  manner 
affected  by  a  uniform  succession  of  gentle  movements,  as  we  see  in  the  mode 
in  which  the  nurses  "  hush-off"  infants,  or  in  the  practice  of  gently  rubbing  some 
part  of  the  body,  which  has  been  successfully  employed  by  many  who  could  not 
otherwise  compose  themselves  to  sleep.  The  reading  of  a  dull  book  acts  in  the 
same  mode  through  the  visual  sense ;  for  the  eyes  wander  on  from  line  to  line 
and  from  page  to  page,  receiving  a  series  of  sensorial  impressions  which  are 
themselves  of  a  very  monotonous  kind,  and  which  only  tend  to  keep  the  atten- 
tion alive  in  proportion  as  they  excite  interesting  ideas. — In  these  and  similar 
cases,  the  influence  of  external  impressions  would  seem  to  be  exerted  in  with- 
drawing the  mind  from  the  distinct  consciousness  of  its  own  operations  (the  loss 
of  which  is  the  transition-state  into  that  of  complete  unconsciousness),  and  in 
suspending  the  directing  power  of  the  Will.  And  this  is  the  case  even  where 
the  attention  is  in  the  first  instance  voluntarily  directed  to  them;  as  in  some  of  the 
plans  which  have  been  recommended  for  the  induction  of  sleep,  when  there  ex- 
ists no  spontaneous  disposition  to  it.  In  other  methods,  the  attention  is  fixed 
upon  some  internal  train  of  thought,  which,  when  once  set  going,  maybe  carried 
on  automatically ;  such  as  counting,  or  repeating  a  French,  Latin,  or  Greek  verb. 
In  either  case,  when  the  sensorial  consciousness  has  been  once  steadily  fixed,  the 
monotony  of  the  impression  (whether  received  from  the  Organs  of  Sense  or 
from  the  Cerebrum)  tends  to  retain  it  there;  so  that  the  Will  abandons,  as  it 
were,  all  control  over  the  operations  of  the  mind,  and  allows  it  to  yield  itself  up 
to  the  soporific  influence.  This  last  method  is  peculiarly  effectual,  when  the 
restlessness  is  dependent  upon  some  mental  agitation,  provided  that  the  Will 
has  power  to  withdraw  the  thoughts  from  the  exciting  subject,  and  to  reduce 
them  to  the  tranquillizing  state  of  a  mere  mechanical  repetition. 

842.  The  access  of  Sleep  is  sometimes  quite  sudden ;  the  individual  passing 
at  once  from  a  state  of  complete  mental  activity  to  one  of  entire  torpor.  More 
generally,  however,  it  is  gradual ;  and  various  intermediate  phases  may  be  de- 
tected, some  of  which  bear  a  close  resemblance  to  the  state  of  Reverie,  whose 
peculiar  nature  has  been  already  described  (§  824).  The  same  ma}7  be  said  with 
regard  to  the  transition  from  the  state  of  Sleep  to  that  of  wakeful  activity ;  for 
this  also  may  be  sudden  and  complete,  although  it  usually  consists  of  a  succes- 
sion of  stages — the  complete  consciousness  of  the  individual's  relation  to  the 
external  world,  and  the  power  of  directing  his  thoughts  and  actions  to  any  sub- 
ject about  which  he  may  be  required  to  exert  himself,  being  the  last  to  be  ac- 
quired. There  maybe  a  rapid  alternation  of  these  different  states;  the  loss  and 
recovery  of  the  waking  consciousness  being  many  times  repeated  in  the  course 
of  a  few  minutes,  when  the  circumstances  are  such  as  to  prevent  the  access  of 
profound  sleep  by  the  recurrence  of  sensory  impressions;  as  when  a  man  on 
horseback,  wearied  from  want  of  rest,  lapses  at  every  moment  into  a  dozing 
state,  from  which  the  loss  of  the  balance  of  his  body  as  frequently  and  suddenly 
arouses  him;  or  when  a  man  going  to  sleep  in  a  sitting  posture,  gradually  loses 
the  support  of  the  muscles  which  keep  his  head  erect,  his  head  droops  by  degrees 
and  at  last  falls  forwards  on  his  chest,  and  the  slight  shock  thence  ensuing 
partially  arouses  and  restores  his  voluntary  power,  which  again  raises  the  head. 
Similar  fluctuations  occur  in  the  sensory  perceptions;  and  these  may  be  often 
artificially  induced  by  very  simple  means.  "We  find,  for  example,  one  condi- 


822  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

tion  of  sleep  so  light,  that  a  question  asked  restores  consciousness  enough  for 
momentary  understanding  and  reply;  and  it  is  an  old  trick  to  bring  sleepers 
into  this  state,  by  putting  the  hand  into  cold  water,  or  producing  some  other 
sensation,  not  so  active  as  to  awaken,  but  sufficient  to  draw  the  mind  from  a 
more  profound  to  a  lighter  slumber.  This  may  be  often  repeated,  sleep  still 
going  on;  but  make  the  sound  louder  and  more  sudden,  and  complete  waking 
at  once  ensues.  The  same  with  other  sensations.  Let  the  sleeper  be  gently 
touched,  and  he  shows  sensibility,  if  at  all,  by  some  slight  muscular  move- 
ment. A  ruder  touch  excites  more  disturbance  and  motion,  and  probably 
changes  the  current  of  dreaming ;  yet  sleep  will  go  on ;  and  it  often  requires  a 
rough  shaking,  particularly  in  young  persons,  before  full  wakefulness  can  be 
obtained."  *  *  *  "It  is  certain  that  the  faculties  of  sensibility  and  volition  are 
often  unequally  awakened  from  sleep.  The  case  may  be  stated,  familiar  to 
many,  of  a  person  sleeping  in  an  upright  posture,  with  the  head  falling  over 
the  breast ;  in  whom  sensibility  is  suddenly  aroused  by  some  external  impres- 
sion, but  who  is  unable,  for  a  certain  time,  to  raise  his  head,  though  the  sensa- 
tion produced  by  this  delay  of  voluntary  action  is  singularly  distressing."  These 
various  cases,  it  is  justly  remarked  by  Dr.  Holland,1  depending  severally  on  the 
intensity  of  sleep,  and  on  the  kind  and  degree  of  the  external  exciting  causes, 
will  be  found  to  explain  many  of  those  so-called  Mesmeric  phenomena  which 
are  offered  to  us  under  a  widely  different  interpretation.  And  it  may  be  here 
remarked,  that  among  those  intermediate  states  between  sleep  and  waking,  which 
either  occur  spontaneously,  or  can  be  induced  in  numerous  individuals  by  very 
simple  processes  (§§  825,  827),  there  are  several  which  exhibit  peculiarities  that 
are  not  in  themselves  in  the  least  degree  less  remarkable  than  are  those  which 
are  regarded  with  so  much  wonder  by  the  uninformed  observer,  when  induced 
by  the  asserted  Mesmeric  influence,  and  paraded  as  specimens  of  its  powers  (see 
§  845,  note). 

843.  It  is  unquestionable  that  the  supervention  of  Sleep  may  be  promoted  by 
the  strong  previous  expectation  of  it ;  and  this  is  true,  not  merely  of  ordinary 
sleep,  but  of  the  states  of  artificial  Reverie  and  Somnambulism  formerly  de- 
scribed. Ever}T  one  knows  the  influence  of  habit,  not  only  in  regard  to  "time," 
but  also  as  to  "  place  and  circumstance,"  in  predisposing  to  Sleep.  Thus,  the 
celebrated  pedestrian  Capt.  Barclay,  when  accomplishing  his  extraordinary  feat 
of  walking  1000  miles  in  as  many  successive  hours,  obtained  at  last  such  a  mastery 
over  himself  that  he  fell  asleep  the  instant  he  lay  down.  And  the  sleep  of 
soldiers,  sailors,  and  others,  who  may  be  prevented  from  obtaining  regular  periods 
of  repose,  but  are  obliged  to  take  their  rest  at  short  intervals,  may  be  almost 
said  to  come  at  command ;  nothing  more  being  necessary  to  induce  it  than  the 
placing  the  body  in  an  easy  position,  and  the  closure  of  the  eyes.  It  is  related 
that  the  Abbe  Faria,  who  acquired  notoriety  through  his  power  of  inducing 
somnambulism,  was  accustomed  merely  to  place  his  patient  in  an  arm-chair,  and 
then,  after  telling  him  to  shut  his  eyes  and  collect  himself,  to  pronounce  in  a 
strong  voice  and  imperative  tone  the  word  "  dormez,"  which  was  usually  success- 
ful. The  Author  has  had  frequent  opportunities  of  satisfying  himself  that  the 
greater  success  which  attends  the  "  hypnotic"  mode  of  inducing  somnambulism 
(§  827)  in  the  hands  of  Mr.  Braid,  its  discoverer,  than  in  that  of  others,  partly 
lies  in  the  mental  condition  of  his  subjects,  who  come  to  him  for  the  most  part 
under  the  confident  expectation  of  its  production,  and  are  further  assured  by  a 
man  of  very  determined  will  that  it  cannot  be  resisted.2  And  it  is  one  of  the 
most  curious  phenomena  of  the  "  biological"  state  (§  825),  that,  in  many  sub- 

1  See  his  excellent  Chapter  on  "  Sleep,"  from  which  the  above  extracts  are  taken,  in  his 
" Medical  Notes  and  Reflections,"  and  his  "Chapters  on  Mental  Physiology." 

2  A  very  amusing  instance  in  which  Sleep,  having  been  previously  induced  by  the  ordi- 
nary "mesmeric"  and  then  by  the  "hypnotic"  processes,  was  brought  on  by  the  simple 


^  THE   CEREBRUM,   AND   ITS   FUNCTIONS.  823 

jects  at  least,  sleep  maybe  induced  in  a  minute  or  less,  by  the  positive  assurance, 
with  which  the  mind  of  the  individual  becomes  possessed,  that  it  will  and  must 
supervene. — The  influence  of  previous  mental  states  is  yet  more  remarkable,  in 
determining  the  effects  produced  upon  the  sleeper  by  different  sensory  impres- 
sions. The  general  rule  is,  that  habitual  impressions  of  any  kind  have  much 
less  effect  in  arousing  the  slumberer  than  those  of  a  new  and  unaccustomed 
character.  An  amusing  instance  of  this  kind  has  been  related  to  the  Author, 
which,  even  if  not  literally  true,  serves  extremely  well  as  an  illustration  of 
what  is  unquestionably  the  ordinary  fact.  A  gentleman  who  had  taken  his 
passage  on  board  a  ship-of-war  was  aroused  on  the  first  morning  by  the  report 
of  the  morning  gun,  which  chanced  to  be  fired  just  above  his  berth ;  the  shock 
was  so  violent  as  to  cause  him  to  jump  out  of  bed.  On  the  second  morning  he 
was  again  awoke,  but  this  time  he  merely  started  and  sat  up  in  bed ;  on  the 
third  morning  the  report  had  simply  the  effect  of  causing  him  to  open  his  eyes 
for  a  moment,  and  turn  in  his  bed  ;  on  the  fourth  morning  it  ceased  to  affect 
him  at  all,  and  his  slumbers  continued  to  be  undisturbed  by  the  report,  so  long 
as  he  remained  on  board.  It  often  happens  that  sleep  is  terminated  by  the 
cessation  of  an  accustomed  sound,  especially  if  this  be  one  whose  monotony  or 
continuous  repetition  had  been  the  original  inducement  to  repose.  Thus,  a 
person  who  has  been  read  or  preached  to  sleep,  will  awake,  if  his  slumber  be 
not  very  profound,  on  the  cessation  of  the  voice ;  and  a  naval  officer,  sleeping 
beneath  the  measured  tread  of  the  watch  on  deck,  will  awake  if  that  tread  be 
suspended. — In  this  latter  case,  the  influence  of  the  simple  cessation  of  the  im- 
pression will  be  augmented  by  the  circumstance  next  to  be  alluded  to,  which 
has  received  too  little  attention  from  writers  on  this  subject,  but  which  is  of 
peculiar  interest  both  in  a  physiological  and  psychological  point  of  view,  and  is 
practically  familiar  to  almost  every  one.  This  is,  that  the  awakening  power  of 
sensory  impressions  is  greatly  modified  by  our  habitual  state  of  mind  in  regard 
to  them.  Thus,  if  we  are  accustomed  to  attend  to  these  impressions,  and  our 
perception  of  them  is  thus  increased  in  acuteness,  we  are  much  more  easily 
aroused  by  them,  than  we  are  by  others  which  are  in  themselves  much  stronger, 
but  which  we  have  been  accustomed  to  disregard.  Thus,  most  sleepers  are  aroused 
by  the  sound  of  their  own  names  uttered  in  a  low  tone,  when  it  requires  a  much 
louder  sound  of  a  different  description  to  produce  any  manifestation  of  conscious- 
ness. The  same  thing  is  seen  in  comatose  states ;  a  patient  being  often  capable 
of  being  momentarily  aroused  by  shouting  his  name  into  his  ear,  when  no  other 
sound  produces  the  least  effect.  The  following  circumstance,  communicated  to 
the  Author  by  the  late  Sir  Edward  Codrington,  is  a  most  apposite  illustration 
of  this  principle.  When  a  young  man,  he  was  serving  as  signal-lieutenant 
under  Lord  Hood,  at  the  time  when  the  French  fleet  was  confined  in  Toulon 
harbor  ;  and  being  desirous  of  obtaining  the  favorable  notice  of  his  commander, 
he  devoted  himself  to  his  duty — that  of  watching  for  signals  made  by  the  look- 
out frigates — with  the  greatest  energy  and  perseverance,  often  remaining  on 
deck  nineteen  hours  out  of  the  twenty-four,  with  his  attention  constantly 
directed  towards  this  one  object.  During  the  few  hours  which  he  spent  in 
repose,  his  sleep  was  so  profound,  that  no  noise  of  an  ordinary  kind,  however 
loud,  would  awake  him ;  and  it  used  to  be  a  favorite  amusement  with  his  com- 
rades, to  try  various  experiments  devised  to  test  the  soundness  of  his  sleep. 
But  if  the  word  "  signal"  was  even  whispered  in  his  ear,  he  was  instantly 
aroused,  and  fit  for  immediate  duty. — The  influence  of  habitual  attention  is 
shown  as  much  in  the  effect  produced  by  the  cessation,  as  in  that  of  the  occur- 
rence, of  sensory  impressions.  Thus  in  the  case  of  the  naval  officer  aroused  by 

belief  that  a  new  process  was  being  put  in  practice,  will  be  found  in  the  "Brit,  and  For. 
Med.  Rev.,"  vol.  xix.  p.  477. 


824  OF  THE   FUNCTIONS   OF   THE   NERVOUS   SYSTEM. 

the  suspension  of  the  measured  tread  of  the  watch  over  his  head,  the  know- 
ledge possessed,  during  the  waking  state,  that  this  suspension  is  either  an  act  of 
negligence  which  requires  notice,  or  indicates  some  unusual  occurrence,  doubt- 
less augments  the  effect  which  the  discontinuance  of  the  sound  would  of 
itself  produce.  It  is  not  requisite,  however,  that  the  sound  should  be  one 
habitually  attended  to  during  the  hours  of  watchfulness ;  for  it  is  sufficient  if  it 
be  one  on  which  the  attention  has  been  fixed  as  that  at  which  the  slumberer  is 
to  arouse  himself.  Thus  the  medical  man,  even  in  his  first  profound  sleep  after 
a  fatiguing  day's  work,  is  aroused  by  the  first  stroke  of  the  clapper  of  his  night- 
bell  ;  and  to  those  who  are  accustomed  to  rise  every  morning  at  the  sound  of 
an  alarm-clock,  the  frequency  and  regularity  of  the  occurrence  do  not  diminish, 
but  rather  increase  the  readiness  with  which  it  produces  its  effect,  provided  that 
the  warning  be  promptly  obeyed.  On  this  usually  depends  the  efficiency  of  the 
awakening  sound;  if  it  be  disregarded  as  a  thing  to  which  there  is  no  occasion 
to  give  heed,  it  very  soon  ceases  to  produce  any  effect,  the  entire  peal  not  being 
sufficient  to  awake  the  sleeper;  whilst,  on  the  other  hand,  the  first  stroke  is 
enough  to  break  the  repose  of  him  who  is  impressed  with  the  effectual  desire  of 
profiting  by  the  warning.  And  thus  it  may  happen  that,  of  two  persons  in  the 
same  room,  either  shall  be  at  once  aroused  by  a  sound  which  produces  no  dis- 
turbance in  the  slumbers  of  the  other.  To  this  influence  of  previous  impres- 
sions, whether  habitual,  or  but  once  forcibly  made,  we  are  also  to  refer  the  spon- 
taneous termination  of  the  state  of  sleep  at  particular  times,  without  any  sensorial 
excitement  from  external  impressions.  Thus,  many  persons  who  are  accustomed 
to  rise  at  a  particular  hour,  wake  regularly  at  that  hour,  whether  they  have 
gone  to  rest  early  or  late ;  so  that  the  act  of  spontaneously  awakening  is  no 
proof  that  the  desirable  amount  of  repose  has  been  obtained.  But  what  is  more 
remarkable  is,  that  many  individuals  have  the  power  of  determining,  at  the 
time  of  going  to  rest,  the  hour  at  which  they  shall  rise,  so  as  to  awake  from  a 
profound  sleep  at  the  precise  time  fixed  upon.  In  others,  however,  the  desire 
to  rise  at  a  particular  hour  only  induces  a  state  of  restlessness  throughout  the 
night,  destroying  the  soundness  of  the  slumbers :  the  individual  awakes  many 
times  in  the  night,  with  the  belief  that  the  hour  is  past,  and  very  possibly  over- 
sleeps it  after  all,  the  system  being  worn  out  by  the  need  of  repose. 

844.  The  Amount  of  Sleep  required  by  Man  is  affected  by  so  many  condi- 
tions, especially  age,  temperament,  habit,  and  previous  exhaustion,  that  no 
general  rule  can  be  laid  down'on  the  subject. — The  condition  of  the  foetus  in 
utero  may  be  regarded  as  one  of  continual  slumber;  the  apparatus  of  animal  life 
being  completely  secluded  from  all  stimuli  which  could  arouse  it  into  activity, 
whilst  the  energy  of  the  organic  functions  is  entirely  directed  to  the  building  up 
of  the  fabric.  On  its  first  entrance  into  the  world,  the  infant  continues  to  pass 
the  greater  part  of  its  time  in  slumber;  and  this  is  particularly  to  be  noticed  in 
cases  of  premature  birth,  the  seven  months'  child  seeming  to  awake  only  for  the 
purpose  of  receiving  food,  and  giving  but  little  heed  to  external  objects,  whilst 
even  the  eight  months'  child  is  considerably  less  alive  to  sensory  impressions 
than  one  born  at  the  full  time.  The  excess  of  activity  of  the  constructive  over 
the  destructive  operations,  which  characterizes  the  whole  period  of  infancy, 
childhood,  and  adolescence  (§§  129 — 131),  requires  that  a  larger  proportion  of 
the  diurnal  cycle  shall  be  passed  in  sleep  (during  which  the  former  may  be 
carried  on  without  hinderance),  than  is  requisite  when  adult  age  has  been  at- 
tained, the  two  sets  of  changes  being  then  balanced  (§  132) ;  and  the  amount 
of  sleep  to  which  the  system  shows  itself  disposed,  gradually  diminishes  from 
three-fourths  to  one-half,  and  from  one-half  to  one-third,  or  even  to  one-quarter, 
of  the  twenty-four  hours.  It  is  to  be  noticed  that  the  sleep  of  children  or 
young  persons  is  not  only  longer  than  that  of  adults,  but  is  also  more  profound. 
On  the  other  hand,  as  age  advances,  and  the  bodily  and  mental  activity  of  the 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  825 

waking  state  decrease,  a  smaller  amount  of  sleep  suffices ;  or,  if  the  slumber  be 
protracted,  it  is  usually  less  deep  and  refreshing.  It  may  be  noticed,  however, 
that  very  old  persons  usually  pass  a  large  proportion  of  their  time  in  sleep,  or 
rather  in  a  sort  of  heavy  doze,  especially  after  meals ;  as  if,  in  consequence  of 
the  want  of  energy  of  their  nutritive  operations,  a  very  long  period  of  repose  is 
necessary  to  repair  the  waste  which  takes  place  during  their  short  period  of 
activity. — In  regard  to  the  influence  of  temperament,  it  may  be  remarked  that 
a  plethoric  habit  of  body,  sustained  by  full  diet,  usually  predisposes  to  sleep, 
provided  that  the  digestive  powers  be  in  a  vigorous  condition ;  persons  of  this 
constitution  frequently  pass  nine  or  ten  hours  in  slumber,  and  maintain  that 
they  cannot  be  adequately  refreshed  by  less.  On  the  other  hand,  thin  wiry 
people,  in  whom  the  "nervous"  temperament  predominates,  usually  take  com- 
paratively little  sleep,  notwithstanding  the  greater  activity  of  their  nervous 
system  when  they  are  awake  ;  but  their  slumber,  while  it  lasts,  is  generally 
very  deep.  Persons  of  "lymphatic"  temperament,  heavy  passionless  people, 
who  may  be  said  to  live  very  slowly,  are  usually  great  sleepers ; '  but  this  rather 
because,  through  the  dulness  of  their  perceptions,  they  are  less  easily  kept 
awake  by  sensorial  or  mental  excitement,  than  because  they  really  require  a 
prolonged  cessation  of  activity.  As  they  are  half  asleep  during  the  waking 
state,  so  would  it  appear  that  the  constructive  operations  must  be  far  from 
active  while  they  are  asleep,  so  little  do  they  seem  restored  by  the  repose. — The 
amount  of  sleep,  caeteris  paribus,  required  by  individuals,  is  very  greatly 
influenced  by  habit;  and,  contrary  to  what  we  might  anticipate,  we  find  that 
the  briefest  sleepers  have  usually  been  men  of  the  greatest  mental  activity. 
Thus  Frederick  the  Great  and  John  Hunter  are  said  to  have  only  required  five 
hours'  sleep  out  of  the  twenty-four.  General  Elliot,  celebrated  for  his  defence 
of  Gibraltar,  is  recorded  not  to  have  slept  more  than  four  hours  out  of  the 
twenty -four.  It  may  be  doubted  whether  it  would  be  possible  for  any  one  to 
sustain  a  life  of  vigorous  exertion  upon  a  smaller  allowance  than  this;  and  the 
general  fact  is,  that  from  six  to  eight  hours  of  repose,  out  of  every  twenty-four, 
are  required  to  keep  the  system  of  an  adult  in  a  state  of  healthful  activity. 
The  influence  of  habit  may  be  brought  to  bear  on  the  protraction,  as  well  as  on 
the  abbreviation,  of  the  usual  period.  Thus  Quin,  the  celebrated  actor,  could 
slumber  for  twenty-four  hours  successively;  and  Dr.  Reid,  the  metaphysi6ian, 
could  take  as  much  food,  and  afterwards  as  much  sleep,  as  were  sufficient  for 
two  days. — It  is  needless  to  dwell  upon  the  obvious  fact,  that,  other  things 
being  equal,  the  amount  of  sleep  required  by  man  is  proportional  to  the  amount 
of  mental  exertion  put  forth  during  the  waking  hours;  since  this  is  an  obvious 
result  of  what  has  been  laid  down  as  the  cause  of  the  demand  for  sleep.  It 
may  be  remarked,  however,  that  we  must  not  measure  the  amount  of  sleep  by 
its  duration  alone;  since  its  intensity  is  a  matter  of  equal  importance.  The 
light  slumber  which  is  disturbed  by  the  slightest  sounds  cannot  be  as  renovat- 
ing as  the  profound  sopor  of  those  whom  no  ordinary  noise  will  awake. 

845.  There  are  certain  states  of  the  encephalic  centres,  in  which  there  is  an 
entire  absence  of  sleep;  and  this  may  continue  for  many  days,  or  even  weeks  or 
months.  Insomnia  is,  for  instance,  one  of  the  characteristics  of  acute  mania, 
and  may  also  exist  in  various  forms  of  monomania ;  it  is  usually,  also,  one  of 
the  symptoms  of  incipient  meriingeal  inflammation;  and  it  may  constitute  a 
specific  disease  in  itself.  In  all  these  cases,  however,  the  preponderance  of  the 
destructive  processes  over  the  constructive  manifests  itself,  sooner  or  later,  in 
the  exhaustion  of  the  mental  and  bodily  powers.  Thus  mania,  when  prolonged 
or  frequently  occurring,  subsides  into  dementia;  and,  if  it  continue  for  any 
length  of  time,  is  sure  to  be  followed  by  a  great  sense  of  wretchedness  and 
prostration,  frequently  accompanied  by  continual  restlessness.  Such  effects,  too, 
in  a  less  aggravated  degree,  result  from  habitual  deficiency  of  sleep;  whether 


826  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

this  result  from  emotional  excitement,  which  keeps  repose  at  bay,  or  from  a 
voluntary  determination  to  keep  the  intellect  in  activity.  This  is  a  very  com- 
mon occurrence  among  industrious  students,  who,  with  a  laudable  desire  for 
distinction,  allow  themselves  less  than  the  needed  quantum  of  repose.  Head- 
ache, tension,  heat,  throbbing,  and  various  other  unpleasant  sensations  in  the 
head,  give  warning  that  the  brain  is  being  overtasked ;  and  if  this  warning  be 
not  taken,  sleep,  which  it  was  at  first  difficult  to  resist,  becomes  even  more 
difficult  to  obtain ;  a  state  of  general  restlessness  and  feverish  excitement  are 
induced ;  and  if,  in  spite  of  this,  the  effort  be  continued,  serious  consequences, 
in  the  form  of  cerebral  inflammation,  apoplexy,  paralysis,  fever,  insanity,  or 
loss  of  mental  power,  more  or  less  complete,  are  nearly  certain  to  be  induced. 
Some  individuals  can  sustain  such  an  effort  much  longer  than  others,  but  it  is  a 
great  mistake  to  suppose  that  they  are  not  equally  injured  by  it;  in  fact,  being 
possessed  with  the  belief  that  they  are  not  suffering  from  the  exertion,  they  fre- 
quently protract  it  until  a  sudden  and  complete  prostration  gives  a  fearful 
demonstration  of  the  cumulative  effects  of  the  injurious  course  in  which  they 
have  been  persevering.  Those,  consequently,  who  are  earlier  forced  to  give 
way,  are  frequently  capable  of  accomplishing  more  in  the  end. — In  regard  to 
the  degree  of  protraction  of  sleep  which  is  consistent  with  a  healthy  state  of 
the  system  in  other  respects,  it  is  difficult  to  speak  with  certainty.  Of  the 
numerous  well-authenticated  instances  on  record,1  in  which  sleep  has  been  con- 
tinuously prolonged  for  many  days  or  even  weeks,  it  is  enough  here  to  state  that 
they  cannot  be  regarded  as  examples  of  natural  sleep ;  the  state  of  such  persons 
being  more  closely  allied  to  hysteric  coma.  An  unusual  tendency  to  ordinary 
sleep  generally  indicates  a  congested  state  of  the  brain,  tending  to  apoplexy ; 
and  it  has  been  stated  that  apoplexy  has  been  actually  induced  by  the  experi- 
mental attempt  to  ascertain  how  large  a  proportion  of  the  diurnal  cycle  might 
be  spent  in  sleep.  Thus,  on  either  side,  inattention  to  the  dictates  of  Nature, 
in  respect  to  the  amount  of  sleep  required  for  the  renovation  of  the  system, 
becomes  a  source  of  disease,  and  should  therefore  be  carefully  avoided.3 

1  Such,  for  example,  as  that  of  Samuel  Chilton  ("Phil.  Trans.,"  1694),  and  that  of 
Mary  Lyall  ("Trans,  of  Roy.  Soc.  of  Edinb.,"  1818). 

2  On  Mesmerism. — It  appears  to  the  Author  that  the  time  has  now  come,  when  a  tolerably 
definite  opinion  may  be  formed  regarding  a  large  number  of  the  phenomena  commonly 
included  under  the  term  "Mesmerism."     Notwithstanding  the  exposures  of  various  pre- 
tenders, which  have  taken  place  from  time  to  time,  there  remains  a  considerable  mass  of 
phenomena,  which  cannot  be  so  readily  disposed  of,  and  which  appear  to  him  to  have  as 
just  a  title  to  the  attention  of  the  scientific  Physiologist  as  that  which  is  possessed  by  any 
other  class  of  well  ascertained  facts. 

Passing  over,  for  the  present,  the  inquiry  into  the  manner  in  which  these  effects  may  be 
induced,  the  Author  may  briefly  enumerate  the  principal  phenomena  which  he  regards  as 
having  been  veritably  presented  in  a  sufficient  number  of  instances  to  entitle  them  to  be 
considered  as  genuine  and  regular  manifestations  of  the  peculiar  bodily  and  mental  condi- 
tion under  discussion : — 

1.  A  state  of  complete  Coma  or  perfect  insensibility,  analogous  in  its  mode  of  access  and 
departure  to  that  which  is  known  as  the  "  Hysteric  Coma,"  and  (like  it)  usually  distinguish- 
able from  the  Coma  of  Cerebral  oppression  by  a 'constant  twinkling  movement  of  the  eye- 
lids.    In  this  condition,  severe  surgical  operations  may  be  performed,  without  any  con- 
sciousness on  the  part  of  the  patient ;  and  it  is  not  unfrequently  found  that  the  state  of 
torpor  extends  from  the  Cerebrum  and  Sensory  Ganglia  to  the  Medulla  Oblongata,  so  that 
the  respiratory  movements  become  seriously  interfered  with,  and  a  state  of  partial  asphyxia 
supervenes. 

2.  A  state  of  Somnambulism  or  Sleep-waking,  which  may  present  all  the  varieties  of  the 
natural  Somnambulism,  from  a  very  limited  awakening  of  the  mental  powers,  to  the  state 
of  complete  Double  Consciousness,  in  which  the  individual  manifests  all  the  ordinary  powers 
of  his  mind,  but  remembers  nothing  of  what  has  passed  when  restored  to  his  natural 
waking  state;     This  state  of  Somnambulism,  in  the  form  which  it  commonly  takes,  is 
characterized  by  the  facility  with  which  the  thoughts  are  directed  into  any  channel  which 
the  observer  may  desire,  by  the  principle  of  "suggestion;"  and  by  the  want  of  power,  on 


THE   CEREBRUM,    AND   ITS   FUNCTIONS.  827 

the  part  of  the  Somnambulist,  to  apply  the  teachings  of  ordinary  experience  to  the  correc- 
tion of  the  erroneous  ideas  which  are  thus  made  to  occiipy  the  mind.  In  these  particulars, 
this  condition  closely  corresponds  with  that  of  the  Artificial  Somnambulism  or  "hypnotism" 
of  Mr.  Braid  ($  827) ;  and  the  only  peculiarity  in  its  phenomena  which  can  be  regarded  as 
at  all  essential,  consists  in  the  special  relation  which  is  affirmed  to  exist  between  the 
mesmerizer  and  his  "subject."  Now  in  regard  to  the  existence  of  this  rapport,  it  is  spe- 
cially noteworthy  that  it  was  not  discovered  until  long  after  the  practice  of  Mesmerism 
had  come  into  vogue,  having  been  unknown  to  Mesmer  himself  and  his  immediate  disciples ; 
and  that  its  phenomena  have  only  acquired  constancy  and  fixity,  in  proportion  as  its 
(supposed)  laws  have  been  announced  and  received  as  established.  The  history  of  Mes- 
merism, candidly  and  philosophically  analyzed,  affords  abundant  evidence  in  proof  of  this 
position ;  but  the  best  guarantee  of  its  truth  is  drawn  from  the  results  obtained  by  the 
numerous  Mesmerizers,  who  have  begun  to  experiment  for  themselves  without  any  know- 
ledge of  what  they  were  to  expect,  and  who  have  produced  a  great  variety  of  remarkable 
phenomena,  without  having  ever  discovered  this  rapport ;  and  yet  have  obtained  immediate 
evidence  of  it,  when  once  the  idea  has  been  put  into  their  own  minds,  and  thence  into  those 
of  their  "subjects."  It  is  quite  easy  to  understand,  that  if  the  mind  of  the  "subject"  be 
so  yielded  up  to  that  of  the  mesmerizer,  as  to  receive  and  act  upon  any  impression  which 
the  latter  forces  upon  or  even  suggests  to  it,  the  notion  of  this  peculiar  relation  is  as  easily 
communicable  as  any  other,  and  may  exert  a  complete  domination  over  the  "subject," 
through  the  whole  of  the  sleep-waking  state.  Thus  the  commands  or  suggestions  of  the 
mesmerizer  meet  with  a  response  which  those  of  no  other  individual  may  produce ;  in  fact, 
the  latter  usually  seem  to  be  unheard  by  the  somnambule,  simply  because  they  are  not 
related  to  the  dominant  impression — a  phenomenon  of  which  the  experience  of  natural 
somnambulism  is  continually  presenting  examples.  And  further,  it  being  a  fact  that 
individuals  of  what  may  be  termed  the  susceptible  constitution,  have  brought  themselves, 
by  the  habit  of  obedience,  into  complete  subjection  to  the  expressed  or  understood  will  of 
some  other  party,  even  in  the  waking  state,  without  any  mesmeric  influence  whatever,  it 
is  not  at  all  difficult  to  understand  how  such  a  habit  of  attending  to  the  operator,  and  to 
him  alone,  should  be  peculiarly  developed  in  the  state  of  Somnambulism,  in  which  the 
mind  seems  to  have  lost  its  self-acting  power,  and  to  be  the  passive  recipient  of  external 
impressions.  And  the  same  explanation  applies  to  the  other  phenomena  of  this  rapport ; 
such  as  its  establishment  with  any  bystander,  by  his  joining  hands  with  the  mesmerizer 
and  the  somnambule ;  for,  as  already  shown  ($  827),  it  is  quite  sufficient  that  the  som- 
nambule should  be  previously  possessed  with  the  idea  that  this  new  voice  will  thus  be 
audible  to  her,  and  that  she  must  obey  its  behests,  for  it  to  produce  all  the  same  effects 
upon  her  as  that  of  the  mesmerizer  had  previously  done.  In  all  the  successful  experiments 
of  this  kind  which  the  Author  has  seen,  this  previous  idea  was  entertained,  both  by  mes- 
merizer and  somnambule ;  but  in  by  far  the  larger  proportion  of  cases  which  have  fallen 
under  his  notice,  and  especially  when  the  subjects  of  them  were  not  habitudes  of  the  mes- 
meric seances,  the  phenomena  of  this  class  could  not  be  made  to  show  themselves,  the 
consciousness  of  the  somnambule  not  being  limited  to  the  mesmerizer  or  to  those  en  rapport 
with  him,  but  being  equally  extended  to  all  around  her. 

3.  A  frequent  phenomenon  of  this  condition,  and  one  which  has  its  parallel  in  Natural 
Somnambulism,  is  a  remarkable  Exaltation  of  one  or  more  of  the  Senses,  so  that  the  indivi- 
dual becomes  susceptible  of  influences,  which,  in  his  natural  condition,  would  not  be  in  the 
least  perceived.  The  Author  has  witnessed  a  case  in  which  such  an  exaltation  of  the  sense 
of  Smell  was  manifested ;  and  in  the  same  case,  as  in  many  others,  there  was  a  similar 
exaltation  of  the  sense  of  Temperature.  The  exaltation  of  the  muscular  Sense,  by  which 
various  actions  that  ordinarily  require  the  guidance  of  vision,  are  directed  independently 
of  it,  is  a  common  phenomenon  of  the  "mesmeric"  with  various  other  forms  of  artificial 
as  well  as  of  natural  Somnambulism.  The  Author  has  repeatedly  seen  Mr.  Braid's  "hypno- 
tized" subjects  write  with  the  most  perfect  regularity,  when  an  opaque  screen  was  interposed 
between  their  eyes  and  the  paper,  the  lines  being  equidistant  and  parallel ;  and  it  is  not 
uncommon  for  the  writer  to  carry  back  his  pen  or  pencil  to  dot  an  i  or  cross  a  T,  or  make 
some  other  correction  in  a  letter  or  word.  Mr.  B.  had  one  patient  who  would  thus  go  back 
and  correct  with  accuracy  the  writing  on  a  whole  page  of  note-paper ;  but  if  the  paper 
was  moved  from  the  position  it  had  previously  occupied  on  the  table,  all  the  corrections 
were  on  the  wrong  points  of  the  paper  as  regarded  the  actual  place  of  the  writing,  though 
on  the  right  points  as  regarded  its  previous  place;  sometimes,  however,  he  would  take  a 
fresh  departure,  by  feeling  for  the  upper  left  hand  corner  of  the  paper,  and  all  his  correc- 
tions were  then  made  in  their  right  positions,  notwithstanding  the  displacement  of  the 
paper. — To  the  extraordinary  exaltation  of  one  or  more  of  the  senses,  which  is  a  character- 
istic of  this  state,  may  fairly  be  attributed  a  great  number  of  the  phenomena  which  have 
been  supposed  to  indicate  a  peculiar  and  mysterious  influence  exerted  by  the  mesmerizer 
over  his  subject;  since  the  latter  will  be  far  more  receptive  of  "suggesting"  impressions, 


828  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

than  an  ordinary  bystander  would  suppose  possible.  And  it  is  to  be  borne  in  mind  that 
the  concentration  of  the  attention  upon  these  may  often  give  them  a  far  greater  significance 
to  the  individual,  than  they  possess  for  others ;  this,  it  seems  likely,  is  especially  the  case 
in  regard  to  tones  of  voice,  emphasis  of  manner,  &c.,  when  questions  are  propounded. 

4.  The  Muscular  system  may  also  be  excited  to  action  in  unusual  modes,  and  with  un- 
usual energy.     Notwithstanding  the  fallacy  of  many  of  the  cases  of  Cataleptic  rigidity 
which  have  been  publicly  exhibited,  the  Author  is  satisfied,  from  investigations  privately 
made,  of  the  possibility  of  artificially  inducing  this  condition.     A  slight  irritation  of  the 
muscles  themselves,  or  of  the  skin  which  covers  them — as  by  drawing  the  points  of  the 
fingers  over  them,  or  even  wafting  currents  of  air  over  the  surface — is  sufficient  to  excite 
the  tonic  muscular  contraction,  which  may  continue  in  sufficient  force  to  suspend  a  con- 
siderable weight,  for  a  longer  period  than  it  could  be  kept  up  by  any  conceivable  effort  of 
voluntary  power.     But  these  are  phenomena  which  are  quite  as  well  displayed  in  Artificial 
Somnambulism  induced  in  other  ways,  as  they  are  in  the  "mesmeric"  state  ;  and  do  not 
afford,  therefore,  any  more  than  the  preceding,  the  slightest  indication  of  the  speciality  of 
the  latter,  or  the  least  proof  of  any  extraneous  influence  exerted  over  the  "  subject." 

5.  Various  effects,  it  is  asserted,  maybe  produced  upon  the  Organic  Functions  by  "  Mes- 
meric" influence ;  and  it  is  on  account  of  this  agency,  that  it  claims  to  be  admitted  as  a 
directly  curative  agent.     It  will  be  hereafter  shown,  however,  that  effects  of  a  precisely 
similar  kind  may  be  produced  in  other  forms  of  Artificial  Somnambulism,  by  simply  fixing 
the  attention  on  the  part ;  and  that  the  same  may  be  done,  even  in  the  ordinary  waking 
state,  in  certain  subjects  who  can  be  worked  up  to  the  requisite  pitch  of  confident  expecta- 
tion. (See  CHAP,  xviu.) 

The  foregoing  are  the  principal  phenomena  of  the  "  Mesmeric"  state,  in  regard  to  which 
the  Author  feels  his  mind  made  up.  He  does  not  see  why  any  discredit  should  be  attached 
to  them,  since  they  correspond  in  all  essential  particulars  with  those  of  states  which 
naturally  or  spontaneously  occur  in  many  individuals,  and  which  he  has  had  opportunities 
of  personally  observing,  in  cases  in  which  the  well-known  characters  of  the  parties  placed 
them  above  suspicion.  When  the  facility  with  which  the  mind  of  the  Somnambulist  is 
played  on  by  suggestions  (conveyed  either  in  language,  or  through  other  sensations  which 
excite  associated  ideas),  and  the  absence  of  the  corrective  power  ordinarily  supplied  by  past 
experience,  are  duly  kept  in  view,  many  of  the  supposed  "higher  phenomena"  of  Mes- 
merism may  be  accounted  for,  without  regarding  the  patient  on  the  one  hand  as  possessed 
of  extraordinary  powers  of  divination,  or  on  the  other  as  practising  a  deception.  Thus, 
bearing  in  mind  that  Somnambulism  is  an  acted  dream,  the  course  of  which  is  governed 
by  external  impressions,  it  is  easy  to  understand  how  the  subject  of  it  may  be  directed  by 
leading  questions  to  enter  buildings  which  he  has  never  seen,  and  to  describe  scenes  which 
he  has  never  witnessed,  without  any  intentional  deceit.  The  love  of  the  marvellous,  so 
strongly  possessed  by  many  of  the  witnesses  of  such  exhibitions,  prompts  them  to  grasp 
at  and  to  exaggerate  the  coincidences  in  all  such  performances,  and  to  neglect  the  failures ; 
and  hence  reports  are  given  to  the  public,  which,  when  the  real  truth  of  them  is  known, 
prove  to  have  been  the  results  of  a  series  of  guesses,  the  correctness  of  which  is  in  direct 
relation  to  the  amount  of  guidance  afforded  by  the  questions  themselves.  In  like  manner, 
the  manifestations  of  the  excitement  of  the  "phrenological  organs"  seem  to  depend  upon 
the  conveyance  of  a  suggestion  to  the  patient,  either  through  his  knowledge  of  their  sup- 
posed seat,  or  through  the  anticipations  expressed  by  the  bystanders.  Many  instances 
are  recorded,  in  which  the  intention  has  been  stated  of  exciting  one  organ,  whilst  the  finger 
has  been  placed  upon  or  pointed  at  another ;  and  the  resulting  manifestation  has  always 
been  that  which  would  flow  from  the  former.  It  does  not  hence  follow  that  intentional 
deception  is  being  practised  by  the  Somnambulist ;  since  the  condition  of  mind  already 
referred  to  causes  it  to  respond  to  the  suggestion  which  is  most  strongly  conveyed  to  it. 

In  regard  to  the  alleged  powers,  which  are  said  to  be  possessed  by  many  Somnambulists, 
of  reading  with  the  eyes  completely  covered,  or  of  discerning  words  inclosed  in  opaque 
boxes,  or  of  giving  an  account  of  what  is  taking  place  at  a  distance,  all  coming  under  the 
general  term  Clairvoyance,  the  Author  need  only  here  express  his  conviction  that  no  case 
of  this  description  has  ever  stood  the  test  of  a  searching  investigation. 

With  respect  to  the  modes  in  which  the  "  Mesmeric"  Somnambulism  is  induced,  it  ap- 
pears to  him  that  they  are  all  referable  to  those  states  of  monotony  of  sensory  impressions, 
and  of  expectation,  to  which  reference  has  been  already  made  as  among  the  most  potent  of 
the  predisposing  causes  of  conditions  allied  to  Sleep  ($  843).  It  is  asserted  by  Mesmeri- 
zers,  that  they  can  induce  the  "Mesmeric"  state  from  a  distance,  without  the  least  con- 
sciousness on  the  part  of  their  "subjects"  that  any  influence  is  being  exerted  on  them — 
an  assertion,  which,  if  true,  would  go  far  to  establish  the  existence  of  a  force  altogether 
sui  generis,  capable  of  being  transmitted  from  one  individual  to  another.  Here,  however, 
as  in  regard  to  the  "higher  phenomena"  last  adverted  to,  the  Author  feels  compelled  to 


OF   THE    SYMPATHETIC    SYSTEM.    AND   ITS   FUNCTIONS.  829 


6. —  Of  the  Sympathetic  System,  and  its  Functions. 

846.  That  collection  of  scattered  but  mutually-connected  ganglia  and  nerves, 
which  altogether  constitute  what  is  now  generally  designated  the  Sympathetic 
System,  maybe  ranged  under  the  following  groups:  1.  The  isolated  ganglia 
and  nerves  in  immediate  connection  with  the  viscera,  which  seem  to  be  the 
chief  centres  of  the  system  ;  these  form  three  principal  plexuses,  the  cardiac, 
the  solar,  and  the  hypogastric.  2.  The  double  chain  of  prevertebral  ganglia, 
with  connecting  cords,  which  lies  in  front  of  the  Vertebral  column,  and  com- 
municates on  the  one  hand  with  the  spinal  nerves,  and  on  the  other  with  the 
before-named  plexuses.  Under  this  head  we  should  probably  rank  the  minute 
cranial  ganglia,  which  are  situated  in  the  neighborhood  of  the  Organs  of  Sense, 
and  in  immediate  connection  with  the  branches  of  the  5th  Pair  that  proceed  to 
them  ]  these  are  the  ophthalmic,  otic,  spheno-palatine,  and  submaxillary  ganglia. 
3.  The  ganglia  on  the  posterior  roots  of  the  Spinal  nerves ;  under  which  head 
we  are  probably  to  rank  not  only  the  Grasserian  ganglion  of  the  5th  Pair,  but 
also  the  ganglia  near  the  roots  of  the  Pneumogastric  and  Glosso-pharyngeal 
nerves. — The  trunks  of  the  Sympathetic  are  made  up  of  different  orders  of  fibres; 
some  of  these  being  derived  from  the  Cerebro-Spinal  system,  whilst  others  have 
their  central  termination  in  the  vesicular  matter  of  the  Sympathetic  ganglia 
themselves. — These  last,  which  are  all  of  the  "gelatinous"  kind  (§  339),1  are 
most  abundant  in  the  great  visceral  plexuses ;  but  they  may  be  traced  from  the 
prevertebral  ganglia  into  the  spinal  nerves,  where  they  are  reinforced  by  the 
fibres  which  have  their  centres  in  the  ganglia  of  the  posterior  roots.  Thus  it 
appears  that  the  Cerebro-Spinal  and  Sympathetic  systems  interpenetrate  one 
another ;  each  having  its  own  series  of  ganglionic  centres  and  of  trunks  con- 
state that  no  evidence  of  an  affirmative  kind  has  yet  been  adduced,  which  can  be  in  the 
least  degree  satisfactory  to  a  scientific  inquirer,  who  duly  appreciates  all  the  sources  of 
fallacy  to  which  these  occurrences  are  open.  Among  these,  the  state  of  expectation 
on  the  part  of  the  "  subject"  is  the  most  important ;  since  this  has  been  shown,  by  repeated 
experiments,  to  be  of  itself  quite  sufficient  to  induce  the  state,  when  the  "  subject"  has 
been  led  to  entertain  it ;  whilst,  if  it  be  altogether  wanting,  the  most  powerful  mesmeric 
influence,  so  far  as  the  Author's  personal  knowledge  extends  (and  on  this  subject,  he  must 
be  excused  for  trusting  rather  to  the  results  of  his  own  investigations,  than  to  the  state- 
ments of  other  individuals,  however  trustworthy  on  ordinary  matters),  has  always  failed. 
A  very  striking  instance  of  this  kind  is  contained  in  the  "  Brit,  and  For.  Med.  Rev.,"  vol. 
xix.  p.  478,  in  an  Article  to  which  the  Author  may  refer  as  on  the  whole  expressing 
(although  not  written  by  himself)  his  own  opinions  on  this  curious  and  interesting  subject; 
strengthened  as  these  are  by  much  subsequent  inquiry  into  the  phenomena  of  "Hypno- 
tism" and  "  Electro-Biology,"  the  attentive  and  scientific  study  of  which  will  tend,  he 
feels  assured,  to  eliminate  the  true  from  the  false  in  Mesmerism,  more  effectually  than 
any  other  method  of  procedure.  Much  has  been  done  by  the  inquiries  of  Mr.  Braid,  of 
Manchester,  who  discovered  the  "hypnotic"  mode  of  inducing  Artificial  Somnambulism, 
and  who  has  carefully  studied  the  phenomena  of  the  hypnotic  state ;  and  the  Author  feels 
it  due  to  that  gentleman  further  to  mention,  that  very  soon  after  the  publication  of  the 
first  edition  of  Baron  Reichenbach's  researches  on  Odyle,  Mr.  Braid  discovered  their  true 
explanation,  and  exhibited  to  the  Author  many  of  the  "  odylic"  phenomena,  as  the  results 
of  suggestion  in  certain  individuals,  whom  he  had  discovered  to  have  the  power  of  voluntarily 
inducing  o  state  of  Abstraction  or  artificial  reverie,  closely  corresponding  to  what  is  now 
termed  the  Electro-Biological  condition. 

On  the  whole  subject  of  Sleep  and  its  allied  states,  as  well  as  on  that  of  Cerebral  Phy- 
siology generally,  the  Author  would  strongly  recommend  his  readers  to  study  Dr.  Holland's 
"Chapters  on  Mental  Physiology;"  in  which  they  will  find  a  most  valuable  and  suggestive 
collection  of  facts  and  doctrines,  based  upon  an  extended  practical  experience,  and  brought 
to  bear  particularly  upon  the  more  difficult  and  recondite  portions  of  the  inquiry. 

>  It  must  be  carefully  borne  in  mind,  that,  although  the  proper  Sympathetic  fibres  are 
all  gelatinous,  yet  that  the  Cerebro-Spinal  system  contains  gelatinous  fibres  of  its  own, 
which  are  very  abundant  in  some  parts. 


830  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

nected  with  them ;  but  each  system  transmitting  its  own  fibres  into  the  trunks 
of  the  other,  and  even  ganglia  of  the  Sympathetic  being  dispersed  among  the 
Cerebro-spinal  tubules. 

847.  It  is  in  virtue  of  the  connections  of  the  Sympathetic  with  the  Cerebro- 
spinal  system,  that  the  parts  which  are  solely  supplied  with  nerves  from  the 
former  are  capable  of  transmitting  sensory  impressions  to  the  Sensorium,  and 
of  receiving  motor  impulses  from  the  Encephalic  centres.  It  is  true  that,  under 
ordinary  circumstances,  these  parts  are  insensible,  that  is,  impressions  made  upon 
them  do  not  travel  onwards  through  the  Spinal  Cord  to  the  Encephalon  ;  but 
their  sensibility  is  acutely  manifested  in  morbid  states,  in  which  the  impressions 
seem  to  be  propagated  further  than  usual,  in  virtue  of  their  greater  potency. 
That  it  is  the  office  of  the  ganglia  on  the  roots  of  the  Spinal  nerves  to  "  cut  off 
sensation/'  that  is,  to  prevent  the  further  transmission  of  sensory  impressions, 
is  an  old  doctrine ;  and  there  seems  much  reason  to  believe  that  this  may  be 
effected  by  the  free  communication  between  one  fibre  and  another,  which  is  es- 
tablished through  the  vesicular  substance  of  a  ganglion,  so  that  the  whole  force 
of  ordinary  impressions  on  the  nerve-fibres  is  lost  in  diffusion  among  the  rest  of 
their  contents.  The  same  principle  seems  to  apply  to  the  motor  fibres  ;  for  there 
are  cases  which  show  that  when  fibres  obviously  belonging  to  Cerebro-spinal 
nerves  pass  through  Sympathetic  ganglia,  they  do  not  so  rapidly  or  so  surely 
transmit  motor  impulses,  as  when  they  have  no;  such  relation  to  ganglia.1 — 
Although  it  is  not  easy  to  obtain  definite  evidence  of  the  influence  of  the  Sym- 
pathetic system  on  Muscular  Contraction,  since  this  influence  is  extinguished 
within  a  short  time  after  death,  yet  it  has  been  established  by  the  elaborate  re- 
searches of  Prof.  Valentin3  that  contractions  of  the  various  muscular  parts  sup- 
plied by  the  three  great  visceral  plexuses  may  be  excited  by  irritation  applied 
to  their  nerves  and  ganglia.  But  he  has  further  shown  that  the  same  effects 
may  be  produced  by  irritating  the  Prevertebral  ganglia,  the  cords  of  commu- 
nication with  the  Spinal  nerves  which  have  been  sometimes  termed  the  roots  of 
the  Sympathetic,  and  the  roots  of  the  Spinal  nerves  themselves.  It  results 
from  his  inquiries,  that,  although  any  particular  division  of  the  Sympathetic 
nerve  must  be  regarded  as  extremely  complex  in  its  relations,  deriving  its  motor 
fibres  from  many  different  sources,  the  ultimate  distribution  of  these  fibres  is 
sufficiently  simple,  so  that  each  organ  is  definitely  supplied  from  a  certain  part 
of  the  cerebro-spinal  axis.  But  the  fibres  proceeding  from  the  roots  of  the 
cerebro-spinal  nerves  do  not  pass  into  the  nearest  organs,  being  transmitted 
through  three  or  more  of  the  prevertebral  ganglia  of  the  Sympathetic  before 
reaching  their  ultimate  destination ;  thus  the  motor  fibres  of  the  cardiac  plexus 
are  principally  derived  from  the  cervical  portion  of  the  Spinal  Cord,  those  of 
the  solar  plexus  from  the  thoracic  region,  and  those  of  the  hypogastric  plexus 
from  the  dorsal  region.  No  experimental  evidence  has  yet  been  afforded,  that 
the  proper  fibres  of  the  Sympathetic  System  have  any  power  of  exciting  mus- 
cular contraction,  or  that  its  ganglia  can  serve  as  centres  of  reflex  action  to  the 
organs  which  they  supply ;  on  the  contrary,  it  is  quite  certain  that  the  ganglia 
in  the  posterior  roots  of  the  Spinal  nerves  have  no  such  endowment.  And  as 
all  the  facts  which  have  been  supposed  to  indicate  the  existence  of  such  a  power 
may  be  otherwise  explained  in  accordance  with  our  fundamental  doctrine  (§§ 
432-3,  497-8),  it  seems  fair  to  conclude  that  the  motor  power  of  the  Sympathetic 
system — which  is  chiefly  exercised  on  the  muscular  substance  of  the  heart  and 
the  walls  of  the  bloodvessels,  on  the  muscular  coat  of  the  alimentary  canal  and 
of  the  larger  gland-ducts  that  open  into  it,  and  on  the  muscular  walls  of  the 

1  See  Messrs.  Kirkes  and  Paget's  "  Handbook  of  Physiology,"  p.  361,  Am.  Ed. 

2  "De  Functionibus  Nervorum  Cerebralium  et  Nervi  Sympatkici,"  Bernae,  1839;  lib.  ii. 
cap.  2. 


GENERAL  RECAPITULATION;    PATHOLOGICAL   APPLICATIONS.       831 

genitourinary  organs — is  entirely  derived  from  the  Cerebro-Spinal  system. 
In  no  instance,  however,  can  the  Will  exert  any  influence  over  the  movements 
of  these  parts;  they  are  strongly  affected  by  emotional  states  of  mind;  and 
they  frequently  seem  to  respond  to  impressions  made  on  remote  organs.  One 
of  the  most  remarkable  cases  of  a  definite  motion  uniformly  excited  through 
the  Sympathetic  system  is  the  dilatation  of  the  pupil,  which,  after  many  im- 
perfect attempts  to  determine  its  source,  has  now  been  shown  by  the  experiments 
of  MM.  Budge  and  Waller  to  be  effected  ^through  the  cervical  portion  of  the 
Sympathetic.  For  whilst  irritation  of  the  trunk  of  the  cervical  Sympathetic 
by  means  of  the  magneto-electric  machine  produces  dilatation  of  the  pupil  with 
just  as  much  certainty  as  irritation  of  the  3d  pair  determines  its  contraction, 
section  of  that  trunk  occasions  permanent  contraction  of  the  pupil,  the  action 
of  the  3d  pair  being  no  longer  antagonized.  But  this,  like  the  other  motor 
powers  of  the  Sympathetic,  is  dependent  upon  the  Spinal  Cord ;  for  magneto- 
electric  irritation  of  any  part  of  it  between  the  first  cervical  and  the  sixth  dorsal 
vertebra  produces  the  same  effect,  which  is  most  decided  when  the  irritation 
is  applied  to  the  central  part  of  this  region.  It  appears  from  other  experiments, 
that  the  fibres  by  which  this  movement  is  effected  pass  through  the  Grasserian 
ganglion,  and  are  distributed  to  the  eye  by  the  ophthalmic  branch  of  the  5th 
Pair.1 

848.  If,  then,  the  sensori-motor  endowments  of  the  Sympathetic  trunks  be 
restricted  to  those  fibres  which  are  really  Cerebro-Spinal  in  their  origin  or  ter- 
mination, it  remains  to  inquire  what  are  the  functions  of  the  true  Sympathetic 
fibres,  whose  vesicular  centres  lie  in  the  ganglia  of  the  Sympathetic  System. 
Upon  this  point  we  can  only  surmise ;  but  there  appears  strong  ground  for  the 
conclusion,  that  the  office  of  these  fibres  is  to  produce  a  direct  influence  upon  the 
chemico-vital  processes  concerned  in  the  Organic  Functions  of  nutrition,  secre- 
tion, &c.;  an  influence  which,  although  not  essential  to  the  performance  of  each 
separate  act,  may  yet  be  required  to  harmonize  them  all  together,  and  to  bring 
them  into  connection  with  mental  states.     That  the  Nervous  System  does  exert 
such  an  agency  will  be  hereafter  shown  (CHAP,  xvin.) ;  and  reasons  will  there 
be  assigned  for  regarding  the  Sympathetic  fibres  as  its  principal,  if  not  as  its 
sole  channel. 

7. —  General  Recapitulation,  and  Pathological  Applications. 

849.  In  summing  up  the  views  which  have  been  propounded  in  this  Chapter, 
with  regard  to  the  functions  of  the  Nervous  System,  it  will  be  advantageous  to 
follow  the  reverse  order  to  that  which  has  been  previously  adopted,  and  to  pro- 
ceed from  above  downwards,  instead  of  from  below  upwards. 

I.  The  entire  Nervous  System,  like  other  organs  of  the  body,  possesses  vital 
endowments  peculiar  to  itself,  in  virtue  of  which  it  tends  to  respond  in  a  deter- 
minate manner  to  impressions  made  upon  it ;  its  several  parts  being  distin- 
guished by  the  results  of  impressions  acting  upon  each  respectively.  In  so  far, 
then,  as  any  part  of  the  Nervous  System  merely  reacts  upon  impressions  which 
are  made  upon  it,  we  must  regard  its  operations  as  automatic;  and  this  as  much 
when  they  give  rise  to  Psychical  changes,  as  when  they  manifest  themselves  in 
evoking  Muscular  movements,  or  in  modifying  the  processes  of  Nutrition  and 
Secretion. 

ii.  But  the  automatic  actions  of  most  parts  of  the  Nervous  System  are  sub- 
ject, more  or  less  completely,  to  the  domination  of  the  Will,  a  power  which  is 
purely  Psychical,  and  of  which  we  know  nothing  but  what  we  learn  from  our 
own  direct  consciousness  of  its  exercise.  The  power  of  the  Will  is  the  greatest 
over  the  automatic  actions  of  the  highest  portions  of  the  Nervous  Centres,  which 

1  See  "  Gazette  Medicale,"  1851,  Nos.  41,  44. 


832  OP   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

are  concerned  in  psychical  changes ;  whilst  it  has  the  least  influence  over  the 
automatic  actions  of  those  lower  centres  which  minister  solely  to  the  functions 
of  the  bodily  organism. 

in.  The  Cerebrum  is  the  material  organ,  through  whose  instrumentality  all 
the  processes  of  Thought  are  carried  on.  These  processes  are  first  called  into 
activity  by  impressions  conveyed  to  the  vesicular  matter  of  the  Cerebral  surface, 
by  ascending  nerve  fibres  which  proceed  to  it  from  the  Sensory  Ganglia;  and 
the  influence  of  that  activity  is  retransmitted  to  the  Sensory  G-anglia  by  a  con- 
verse set  of  descending  fibres.1  There  is  much  reason  to  consider  that,  until 
such  retransmission  has  taken  place,  the  consciousness  is  not  so  affected  by 
Cerebral  changes  as  to  give  to  the  results  of  these  changes  &  psychical  character; 
for  the  central  Sensorium  appears  to  stand  in  precisely  the  same  anatomical  and 
physiological  relation  to  the  vesicular  matter  of  the  Cerebral  surface  that  it 
does  to  the  vesicular  matter  of  the  Retina  or  other  peripheral  expansions  of  the 
Sensory  nerves ;  and  there  is  strong  analogical  ground  for  the  belief  that  the 
process  by  which  the  Mind  is  rendered  conscious  of  changes  in  the  Cerebrum, 
is  performed  by  the  same  instrumentality  as  that  by  which  it  is  made  acquainted 
with  impressions  on  the  Organs  of  Sense.  And  this  view  is  confirmed  by  the 
fact  that  automatic  changes  may  take  place  in  the  Cerebrum,  without  any  con- 
sciousness on  our  own  parts,  the  results  of  which,  when  we  are  at  last  made 
conscious  of  them,  correspond  with  those  that  we  ordinarily  attain  by  processes 
whose  successive  steps  excite  as  many  successive  states  of  consciousness. 

IV.  These  Cerebral  changes,  then,  acting  downwards  upon  the  Sensorium, 
give  rise  to  those  changes  in  our  consciousness  which  we  designate  as  Mental 
Processes.     These  processes — called  into  activity  by  Sensorial  changes — ranging 
from  the  simple  act  of  Perception  to  the  highest  operations  of  intellectual 
power — consisting  also  in  the  play  of  Fancy  and  Imagination,  and  including 
those  active  states  known  as  Passions,  Emotions,  Moral  Feelings,  Sentiments, 
&c. — must  be  regarded  as  essentially  automatic  in  their  nature,  and  as  the 
manifestations  of  the  "  reflex"  activity  of  the  Cerebrum  ;  since  we  have  abund- 
ant evidence  that  they  can  take  place  without  any  self-direction  on  the  part  of 
the  individual,  who,  whilst  his  Will  is  in  abeyance,  is  in  the  condition  of  an 
animal  entirely  governed  by  Instinct.     There  is,  however,  far  less  of  uniformity 
in  these  "  reflex  actions"  of  the  Cerebrum,  than  we  observe  in  those  reflex 
actions  of  other  parts  of  the  Nervous  System,  which  give  rise  to  the  movements 
ordinarily  designated  as  instinctive  ;  this  diversity  seems  partly  attributable  to 
differences  in  the  original  constitution  of  different  individuals ;  but  it  is  cer- 
tainly due  in  great  part  to  differences  in  the  acquired  constitution  of  the  organ, 
arising  out  of  the  mode  in  which  it  has  been  habitually  exercised — this  being 
dependent,  on  the  one  hand,  on  the  circumstances  in  which  the  individual  has 
been  placed ;  and,  on  the  other,  on  the  use  he  has  made  of  his  Will. 

V.  When  the  power  of  the  Will  has  been  duly  cultivated,  it  acquires  so  com- 
plete a  domination  over  the  automatic  actions  of  the  Cerebrum,  that  it  can  regu- 
late the  course  of  thought  and  the  degree  of  emotional  excitement ;  intensifying 
some  of  these  actions,  and  repressing  others,  by  determinate  efforts  directed  with 
a  special  purpose.     Its  power  is  so  far  limited,  however,  that  it  can  only  select 
from  the  objects  which  spontaneously  present  themselves  to  the  consciousness, 
those  which  it  desires  to  retain  and  employ ;  and  has  no  direct  power  of  bring- 
ing before  the  mind  any  object  not  actually  present  to  it.     Hence  it  is  that, 

1  The  structural  distinctness  of  these  two  sets  of  fibres  must  be  admitted  to  be  hypothe- 
tical, and  it  is  improbable  that  any  anatomical  evidence  can  ever  be  attained,  by  which 
the  hypothesis  may  be  established.  But  all  the  analogy  of  the  afferent  and  efferent  fibres 
throughout  the  body  is  opposed  to  the  idea  that  the  same  fibres  can  serve  both  purposes. 
Whatever  may  be  thought  of  their  structural  distinctness,  however,  there  can  be  no  rea- 
sonable doubt  of  the  transmission  of  nerve-force  in  the  two  directions  above  indicated. 


GENERAL  RECAPITULATION,    PATHOLOGICAL   APPLICATIONS.      833 

whilst  we  have  an  almost  unlimited  power  of  turning  to  the  best  account  the 
endowments  we  possess,  by  strengthening  our  intellectual  powers,  expanding 
our  higher  emotional  tendencies,  and  bringing  the  lower  under  wholesome 
restraint,  we  cannot,  by  any  effort  of  the  Will,  introduce  new  elements  into  our 
psychical  nature.1 

VI.  The  power  of  the  Cerebrum  to  call  forth  muscular  movements  is  entirely 
exerted  through  the  intermediation  of  the  Cranio-Spinal  Axis  upon  which  it  is 
superimposed ;  no  motor  fibres  directly  issuing  from  the  Cerebrum  itself.  These 
movements,  when  directly  determined  by  the  Will,  may  be  designated  as  Voli- 
tional ;  when  they  are  involuntarily  excited  by  states  of  passion,  feeling,  &c.,  of 
which  they  are  the  external  expressions,  they  are  distinguished  as  Emotional ; 
and  when  they  are  prompted,  in  the  absence  of  any  volitional  exertion,  by  domi- 
nant ideas,  they  may  be  termed  IdeationaL  In  each  case  the  nerve-force  trans- 
mitted downwards  from  the  Cerebrum  appears  to  produce  the  very  same  state 
of  activity  in  the  Sensori-motor  apparatus  as  that  which  may  be  directly  excited 
in  it  by  impressions  transmitted  from  the  Organs  of  Sense  ',  and  thus  the  same 
instrumentality  serves  for  all  classes  of  movements,  voluntary  and  involuntary ; 
the  difference  in  their  character  being  solely  referable  to  the  diversity  of  their 
primal  source. 

vii.  The  Cerebrum  being  the  instrument  of  all  psychical  activity,  we  must 
regard  its  action  as  disordered  in  every  state  in  which  that  activity  is  perverted. 
The  first  degree  of  departure  from  the  normal  state  is  usually  shown  in  the 
want  of  Volitional  control  over  the  sequence  of  thought ;  and  this  may  exist 
merely  to  the  extent  of  giving  the  reflex  power  of  the  organ  too  great  a  predomi- 
nance, so  that  trains  of  thought  and  states  of  feeling  succeed  each  other  automa- 
tically, and  all  the  actions  of  the  individual  are  simply  the  expressions  of  these. 
Such  is  the  mental  state  which  exists  in  Reverie  and  in  Somnambulism,  natu- 
ral or  induced  ;  the  principal  varieties  in  these  states  being  traceable  to  the  rela- 
tive degree  of  influence  of  ideas  already  fixed  in  the  mind,  and  of  external  sug- 
gestions, in  determining  the  course  of  thought.  It  is  to  be  remarked,  in  regard 
to  these  conditions,  however,  that  they  are  generally  characterized  by  a  some- 
what inactive  state  of  the  Cerebrum,  so  that  the  changes  in  the  state  of  con- 
sciousness are  not  rapid,  but  such  as  do  occur  are  coherent.3  In  Dreaming, 
Delirium,  and  the  artificial  Delirium  of  Intoxication,  on  the  other  hand,  with  a 
like  absence  of  the  directing  and  restraining  power  of  the  Will,  there  is  a 
greater  and  more  irregular  activity  in  the  Cerebral  operations,  the  ideas  pre- 

1  No  one  has  ever  acquired  the  creative  power  of  genius,  or  made  himself  a  great  artist 
or  a  great  poet,  or  gained  by  practice  that  peculiar  insight  which  characterizes  the  original 
discoverer ;  for  these  gifts  are  mental  instincts  or  intuitions,  which  may  be  developed  and 
strengthened  by  due  cultivation,  but  which  can  never  be  generated  de  novo.     It  not  unfre- 
quently  happens,  however,  that  the  gift  lies  dormant,  until  some  appropriate  impression 
excites  it  into  activity.     Such  is  especially  the  case  with  regard  to  the  higher  Moral  Feel- 
ings, which  are   too  often   so  completely  repressed  by  the  degrading  influences  under 
which  the  youthful  mind  expands  itself,  that  they  might  be  considered  as  altogether  want- 
ing.    Though  dormant,  however,  they  are  rarely  extinct,  and  may  be  called  into  activity 
by  appropriate  management.     It  has  been  by  faith  in  this  principle,  and  by  skill  in  its 
application,  that  those  have  achieved  the  greatest  success  who  have  recently  devoted  them- 
selves to  the  much-needed  work  of  Juvenile  Reformation.     (See  "  Reformatory  School,"  by 
Mary  Carpenter.) 

2  In  most  forms  of  induced  Somnambulism,  it  appears  as  if  the  mental  activity  is  only 
sustained  by  external  prompting,  all  spontaneous  activity  being  suspended;  for  the  "sub- 
ject" continually  relapses  into  a  state  of  unconsciousness,  and  does  not  pass  from  one  sub- 
ject to  another  unless  induced  to  do  so  by  "leading  questions."     In  some  cases  of  this 
kind,  however,  as  well  as  in  all  those  forms  of  natural  Somnambulism  in  which  the  individual 
acts  on  the  spontaneous  promptings  of  his  own  thoughts,  the  mental  state  is  one  of  con- 
tinuous activity ;  but  it  is  obvious  that  its  operations  are  slow,  and  are  very  limited  in 
their  nature. 

53 


8B4  OF   THE    FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

senting  themselves  in  far  more  rapid  succession,  and  possessing  a  less  perfect 
mutual  coherence. 

VIII.  The  foregoing  states  are  closely  allied  to  Insanity;  many  forms  of  which 
may  be  almost  exactly  paralleled  by  transient  states  of  Somnambulism,  whilst 
others  are  but  a  modification  of  Delirium.  A  deficiency  or  entire  absence  of  the 
controlling  power  of  the  Will  is  the  common  feature  of  all  forms  of  this  disorder, 
and  is  frequently  its  first  manifestation.  But  Insanity  is  essentially  constituted 
by  excessive,  deficient,  or  perverted  activity  of  some  one  or  more  of  the  auto- 
matic tendencies,  and  must  thus  be  regarded  as  consisting  in  a  disordered  action 
of  the  Cerebrum.  This  may  be  traced  to  a  great  variety  of  causes,  which  may  be 
classified  in  different  ways,  according  as  we  take  their  own  nature  or  their  modus 
operandi  as  the  basis  of  our  arrangement.  Thus  it  is  unquestionable  that  in  a 
large  proportion  of  cases  of  settled  Insanity,  there  is  an  impairment  of  the  due 
Nutrition  of  the  Cerebrum;  and  this,  which  is  often  an  hereditary  defect,  may' 
arise  de  novo,  like  abnormal  changes  in  the  nutrition  of  other  parts  (CHAP.  XI.), 
from  deficiency  or  perversion  in  the  formative  power  of  the  tissue,  or  from  an 
imperfect  supply,  or  from  an  altered  character  of  its  pabulum.  Of  the  influence 
of  deficient  or  perverted  formative  power  in  the  tissue,  we  have  examples  in  the 
Insanity  resulting  from  mechanical  injuries  of  the  brain,  and  from  excessive 
"wear"  of  the  organ  by  forced  activity.  Of  the  effects  of  deterioration  in  the 
character  of  the  blood,  we  have  illustrations  in  the  Insanity  that  is  often  linked 
on  with  constitutional  diseases  of  which  such  deterioration  is  a  marked  feature, 
and  in  that  which  is  so  frequent  a  consequence  of  habitual  excess  in  the  use  of 
Alcoholic  liquors.  These  conditions  may  exist  in  combination;1  and  it  is,  pro- 
bably, by  such  a  combination  that  many  of  the  "  moral  causes"  of  Insanity 
operate.  For  there  can  be  little  doubt  that  Emotional  excitement,  from  its  im- 
mediate relation  to  Nerve-force  (§  805),  has  a  direct  influence  on  the  formative 
capacity  of  the  Cerebrum  ;  whilst,  on  the  other  hand,  we  know  that  it  has  so 
great  an  influence  over  the  Organic  functions,  that  it  can  produce  very  serious 
alterations  in  the  condition  of  the  Blood  (CHAP.  xvm).  But  without  any  serious 
perversion  of  the  nutrition  of  the  Cerebrum,  its  action  may  be  disturbed,  either 
by  the  presence  of  some  toxic  agent  in  the  Blood,  or  by  functional  disturbance 
in  other  parts  of  the  Nervous  system.  The  delirium  of  Intoxication  is,  whilst 
it  lasts,  a  true  Insanity ;  and  it  ceases  because  the  poison  is  eliminated  from  the 
system.  But  there  are  many  cases  in  which  there  is  a  continual  production  of 
a  poison  within  the  system,  which  deranges  the  normal  train  of  mental  action 
so  long  as  the  blood  is  tainted  by  it ;  the  indication  of  treatment  is  here  ob- 
viously to  check  this  production,  and  to  depurate  the  blood ;  and  when  this  has 
been  effectually  accomplished,  the  healthy  action  of  the  Brain  is  immediately 
restored,  which  would  not  have  been  the  case  if  its  nutrition  had  been  seriously 
impaired.  Most  persons  have  experienced  the  extreme  depression  of  spirits  and 
incapacity  for  mental  exertion,  which  are  consequent  upon  certain  derangements 
of  the  digestive  function,  and  especially  upon  disorder  of  the  biliary  apparatus; 
and  it  is  unquestionable  that  many  forms  of  Insanity,  in  which  extreme  dejec- 
tion is  a  prominent  symptom,  but  which  may  also  include  intellectual  delusions, 

1  Thus  Delirium  tremens,  which  may  be  regarded  as  a  form  of  temporary  Insanity,  essen- 
tially consisting  in  perverted  and  imperfect  nutrition  of  the  Cerebrum,  seems  ordinarily 
dependent  conjointly  upon  the  excessive  and  irregular  activity  to  which  the  organ  has  been 
previously  forced,  and  on  the  alteration  of  the  normal  character  of  the  Blood  produced  by 
the  habitual  presence  of  Alcohol  in  its  current ;  but  it  is  well  known  that  Delirium  tremens 
may  occur  as  the  result  of  other  agencies  that  primarily  depress  the  nutritive  power 
without  perverting  the  blood ;  such  as  excessive  depletion,  the  shock  of  severe  injuries,  or  ex- 
treme cold.  In  either  case,  however,  the  indications  of  treatment  are  the  same ;  namely, 
to  induce  sleep,  whereby  the  irregular  activity  of  the  organ  may  be  completely  suspended, 
and  its  due  nutrition  restored  :  and  to  correct  what  may  be  faulty  in  the  condition  of  the 
blood. 


GENERAL  RECAPITULATION,    PATHOLOGICAL  APPLICATIONS.     835 

are  solely  dependent  upon  this  cause.  The  functional  disturbance  of  the  Cere- 
brum induced  by  the  irregular  action  of  other  parts  of  the  Nervous  System, 
is  a  part  of  the  Etiology  of  Insanity  which  has  been  as  yet  but  very  little  at- 
tended to,  but  which  deserves  a  careful  study.  Numerous  examples  of  it  are 
furnished  by  certain  peculiar  forms  of  disordered  Mental  action,  which  are  con- 
nected with  "  hysterical"  states  of  the  female  system,  especially  mutability  and 
irritability  of  temper  and  disposition  to  deceit;1  but  we  are  probably  also  to  refer 
to  this  cause,  in  part  at  least,  those  very  distressing  states  of  mind  which  arise  out 
of  disorders  in  the  sexual  apparatus  of  the  male,  or  even  from  irritation  of  neigh- 
boring parts.3 — It  frequently  happens  that  agencies  of  both  classes  contribute 
to  the  result ;  some  long-continued  defect  of  nutrition  (very  often  arising  from 
hereditary  constitution)  serving  as  the  "  predisposing  cause,"  whilst  some  vio- 
lent mental  emotion,  or  depravation  of  the  blood  by  some  noxious  matter,  acts 
as  the  "  exciting  cause  •"  the  two  conjointly  producing  that  effect,  which  neither 
would  singly  have  brought  about. 

IX.  Without  any  Mental  perversion,  however,  indicative  of  structural  or  func- 
tional disorder  of  the  Cerebrum,  there  may  exist  a  partial  severance  of  its  con- 
nection with  the  Sensori-motor  apparatus ;  so  that  it  cannot  receive  sensory  im- 
pressions from  particular  organs  or  parts  of  the  body,  or  call  forth  muscular 
movement  in  respondence  to  volitional  determinations  or  to  emotional  excite- 
ment. Or,  again,  there  may  be  a  weakening  of  Voluntary  power  over  the  mus- 
cles in  general,  whilst  they  still  remain  amenable  to  the  stimulus  of  Emotion; 
and  in  such  cases,  as  might  be  expected,  the  influence  of  sensory  impressions  in 
directly  exciting  muscular  movements  is  obviously  manifested.3  Of  the  precise 
pathological  alterations  which  give  rise  to  these  peculiar  conditions  (which  fre- 
quently manifest  themselves  in  regard  to  particular  groups  of  muscles,  such  as 
those  of  vocalization),  nothing  whatever  is  known. — Nearly  allied  to  this  state  is 
that  which  gives  rise  to  the  "  jactitating  convulsion/'  interfering  with  volitional 
movement,  which  is  known  as  Chorea.  On  the  physiological  views  here  advo- 

1  See  Dr.  Laycock's  "  Treatise  on  the  Nervous  Diseases  of  Women,"  in  which  these 
sympathies  are  fully  dwelt  on. 

2  See  M.  Lallemand's  "  Treatise  on  Spermatorrhoea,"  translated  by  Mr.  McDougal. — In 
some  of  the  cases  recorded  by  M.  Lallemand,  the  most  extreme  mental  depression  was  en- 
gendered by  the  presence  of  ascarides  in  the  rectum ! 

3  Of  this  curious  state,  the  following  example  was  communicated  to  the  Author,  about 
four  years  since,  by  his  friend  Mr.  Noble. — "  Mr.  R.,  set.  41,  of  a  sanguine  nervous  tempera- 
ment, a  married  man,  and  father  of  several  children,  the  youngest  being  but  two  months 
old,  exhibited  the  following  symptoms,  first  experienced  in  a  slight  degree  about  five  years 
ago,  and  since  then  having  become  much  aggravated,  the  climax  having  apparently  been 
attained  about  two  years  ago. — There  was  partial  paralysis  of  voluntary  motion  upon  the 
left  side,  exhibiting  under  ordinary  circumstances  the  customary  phenomena;  but  with  this 
peculiarity — that  although  Volition  was  comparatively  powerless,  any  incident  excitor  im- 
pression of  an  unusual  character,  by  exciting,  as  it  were,  Consensual  action,  would  give 
effect  to  the  voluntary  intention ;  thus  when  the  affected  arm  was  raised  by  another  to  a 
certain  height,  the  patient  was  unable  by  mere  volition  to  elevate  it  still  more  ;  but  if  the 
hand  were  smartly  struck  or  blown  upon  either  by  himself  or  by  another,  movement  of  a 
rapid  character  would  at  once  ensue,  and  that  too  in  conformity  with  the  Volitional  effort. 
Upon  inquiry,  moreover,  it  appeared  that  any  unwonted  impression  upon  the  internal  as 
well  as  the  external  senses  was  capable  of  leading  to  a  realization  of  the  effort  vainly  at- 
tempted by  the  mere  will ;  hence,  by  accomplishing  the  commencement  of  a  run  or  trot  by 
aid  of  some  undue  impression,  he  could  go  on ;  he  stated,  on  the  case  being  proposed,  that 
if,  in  utter  paralysis  of  voluntary  power  over  the  muscles,  a  hundred-pound  note  were  sud- 
denly placed  before  his  vision,  and  he  were  told  tKat  on  seizing  it  the  same  should  be  his, 
he  should  at  once  be  equal  to  the  requisite  effort. — When  in  health,  Mr.  R.  stated  that  he 
had  excellent  controlling  power  over  the  Emotions,  but  that  now  the  pleasure  and  the  pain 
attendant  upon  their  excitation  were  exalted,  and  the  consensual  phenomena  quite  irre- 
sistible ;  and  on  further  inquiry  it  appeared  that,  in  the  matter  of  laughing  and  crying,  he 
exhibited  very  much  of  the  hysterical  condition.     In  early  life,  Mr.  R.  had  been  what  is 
called  a  free  liver;  both  in  regard  to  women,  and  to  alcoholic  stimulants." 


836  OF   THE   FUNCTIONS   OF   THE    NERVOUS    SYSTEM. 

cated,  this  disease  must  be  regarded  as  consisting  essentially  in  a  diminution  of 
the  power  of  the  Will  (exerted  through  the  Cerebrum)  over  the  muscular  ap- 
paratus, concurrently  with  an  augmented  and  perverted  activity  of  the  Sensori- 
motor  centres.  That  its  special  seat  is  at  the  summit  of  the  Cranio-Spinal  axis, 
where  it  comes  into  connection  with  the  Cerebrum,  would  appear  from  several 
considerations,  particularly  from  the  interruption  of  voluntary  power,  the  aggra- 
vation of  the  movements  by  emotion,  and  their  cessation  during  sleep  ;  the  two 
latter  facts  being  inconsistent  with  the  idea  that  the  proper  Spinal  centres  are 
essentially  involved,-  although  they  are  frequently  affected  coincidently  or  sub- 
sequently. The  choreic  convulsion  is  occasionally  hemiplegic  ;  and  it  sometimes 
gives  place  to  paralysis,  which  is  seldom  complete,  however,  and  may  usually  be 
cured  by  appropriate  treatment.  This  disorder  appears  generally  traceable  to  a 
state  of  imperfect  nutrition,  dependent  upon  a  depraved  and  perhaps  a  poisoned 
state  of  the  blood,  rather  than  on  any  organic  lesion.1  Not  unfrequently  the 
defect  of  nutrition  seems  to  act  as  the  " predisposing  cause"  of  the  disease;  the 
attack  being  immediately  traceable  to  mental  emotion.2 — Stammering  may  be 
regarded  as  a  sort  of  Chorea,  affecting  the  muscles  of  Voice. 

x.  The  Sensory  Ganglia,  collectively  constituting  the  Sensorium,  may  be 
regarded  as  the  most  essential  part  of  the  Encephalon;  since  we  find  them  fully 
developed  in  animals  which  scarcely  possess  a  rudiment  of  a  Cerebrum,  and 
presenting  the  same  relative  condition  to  the  latter  in  the  early  embryo  of  Man. 
They  directly  receive  the  nerves  proceeding  from  the  organs  of  Special  Sense, 
each  pair  of  which  has  its  own  distinct  ganglionic  centre;  and  they  receive,  also, 
through  the  (so-called)  Crura  Cerebri,  the  nerves  of  "  common  sensation/'  whose 
ganglionic  centre  appears  to  lie  in  the  Thalami  Optici.  They  give  off  a  large 
number  of  motor  fibres,  which,  descending  through  the  Crura  Cerebri,  are  distri- 
buted, with  the  fibres  proceeding  from  the  Spinal  ganglia,  through  the  various 
motor  trunks,  to  the  muscular  system  generally.3  On  the  other  hand,  by  one 
set  of  the  radiating  fibres  of  the  Cerebral  substance,  they  transmit  sensorial  im- 
pressions upwards  to  the  vesicular  surface  of  the  Hemispheres;  whilst  conversely, 
by  its  descending  fibres,  they  receive  the  impressions  transmitted  downwards 
from  the  Cerebral  ganglia ;  and  they  thus  constitute  the  medium  by  which  alone 
the  Cerebrum  communicates  with  the  Organs  of  Sense  on  the  one  hand,  and 
with  the  muscular  apparatus  on  the  other. — The  Sensory  Ganglia  must  be 
collectively  regarded  as  forming  the  organ  through  whose  instrumentality  the 
Mind  is  rendered  conscious  of  impressions  made  on  the  Organs  of  Sense ;  and 
reasons  have  been  advanced  for  the  belief,  that  it  also  serves  as  the  instrument 
whereby  the  Consciousness  is  affected  by  Cerebral  changes,  which,  in  so  far  as 
they  take  place  independently  of  the  Will,  are  the  cause  and  not  the  consequence 
of  Mental  activity.  There  is  no  reason  to  think  that  the  Sensorium  has  in  itself 
any  higher  function  than  that  of  impressing  the  consciousness  of  the  individual; 
this  impression  on  the  consciousness,  when  made  by  an  external  agency  operat- 
ing through  the  sensory  nerves,  is  that  which  is  known  as  Sensation;  but, 
when  produced  by  Cerebral  changes,  it  constitutes  Ideation.  With  the  states 

1  See  Dr.  Todd's  Lumleian  Lectures  "On  the  Pathology  and  Treatment  of  Convulsive 
Diseases"  in  the  "  Medical  Gazette,"  April  20  and  27,  1849. 

2  A  remarkable  number  of  cases  of  Chorea  were  admitted  into  the  Bristol  Infirmary 
within  a  few  weeks  after  the  memorable  Riots  of  1833. 

3  The  doctrine  previously  advocated  (g  701),  that  there  is  an  actual  continuity  of  fibres 
between  the  Sensorial  centres  and  the  roots  of  the  Spinal  Nerves,  has  lately  received  very 
important  confirmation  from  the  elaborate  researches  of  Dr.  Turck  on  the  alterations  pro- 
duced in  the  Spinal  Cord  by  Hemiplegia  originating  in  intra-cranial  lesion.     See  his 
Memoir  "  Uber  secondiire  Erkrankung  einzelner  lliickensinarksstriinge  und  ihrer  Fortset- 
zungen  zum  Gehirne,"in  "  Denkschriften  der  kaiserlichen  Academic  der  Wissenschaften," 
Wein,  1851. 


GENERAL   RECAPITULATION,   PATHOLOGICAL   APPLICATIONS.     837 

of  consciousness  termed  Sensations  are  associated  the  simple  feelings  of  pleasure 
and  pain,  the  seat  of  which  is  obviously  sensorial ;  and  similar  feelings,  associat- 
ing themselves  with  those  states  of  consciousness  termed  Ideas,  give  to  them 
an  Emotional  character,  and  become  the  sources  of  those  motives  by  which  the 
determination  of  conduct  made  by  the  Reason  is  in  great  part  guided. 

XI.  The  "reflex  action"  of  the  Sensory  Ganglia,  which  proceeds  from  their 
own  independent  activity,  is  manifested  in  all  those  instinctive  or  automatic 
movements,  which  are  excited  through  sensations,  and  which  may  hence  be 
designated  as  consensual  or  sensor  i-motor.  These  actions  are  but  little  noticed, 
in  Man,  in  the  active  state  of  his  Cerebrum;  for  the  automatic  movements  on 
which  the  maintenance  of  his  organic  functions  is  immediately  dependent  are 
provided  for  by  the  Spinal  centres;  and  the  purposes  which  are  answered  in 
the  lower  animals  by  the  higher  order  of  Instinctive  actions  are  worked  out  in 
him  by  the  Intelligence.  There  is,  however,  a  large  group  of  secondarily^ 
automatic  movements,  which,  though  originally  determined  by  the  Will,  are 
brought  by  habit  so  far  under  the  direct  influence  of  sensations,  that  they  con- 
tinue, whilst  prompted  and  guided  by  the  latter,  after  the  Will  has  ceased  to 
act. — The  operation  of  the  Sensory  Ganglia  in  Man  is  usually  subservient  to 
that  of  the  Cerebrum ;  for  the  influence  of  Sensational  changes,  being  propa- 
gated upwards  to  that  organ,  excites  further  changes  in  it;  these,  reflected 
downwards  to  the  Sensori-motor  centres,  become  the  sources  of  ideational  or  of 
emotional  movements;  and  the  determining  power  of  the  Will,  in  producing 
volitional  movements,  is  exercised  through  the  same  channel.  It  is  a  remarka 
ble  indication  of  the  participation  of  the  Sensorial  centres  even  in  volitional 
movements  that  these  cannot  be  executed  save  with  the  concurrence  of  guiding 
sensations.  The  extent  to  which  the  Sensory  Ganglia  may  act  as  independent 
centres  of  action  is  seen  in  cases  in  which  the  functions  of  the  Cerebrum  are 
entirely  in  abeyance.  This  may  happen  through  congenital  defect,  as  in  some 
cases  of  complete  Idiocy,  especially  among  the  Cretins  of  the  first  degree,  who 
spend  their  whole  time  in  basking  in  the  sun  or  sitting  by  the  fire  (experiencing 
merely  sensorial  pleasure),  and  who  show  no  higher  traces  of  intelligence  than 
is  evinced  by  their  going,  when  excited  by  hunger,  to  the  places  where  they 
have  been  accustomed  to  receive  food.  It  may  occur,  too,  as  a  consequence  of 
disease  or  injury.  Of  this  we  have  an  example  in  a  case  mentioned  by  Dr. 
Rush,  of  a  man  who  was  so  violently  affected  by  some  losses  in  trade,  that  he 
was  deprived  almost  instantly  of  his  mental  faculties;  he  did  not  take  the 
slightest  notice  of  anything,  not  even  expressing  a  desire  for  food,  but  merely 
receiving  it  when  it  was  put  into  his  mouth ;  a  servant  dressed  him  in  the 
morning,  and  conducted  him  to  a  seat  in  his  parlor,  where  he  remained  the 
whole  day,  with  his  body  bent  forwards  and  his  eyes  fixed  on  the  floor;  in  this 
state  he  continued  for  five  years,  and  then  recovered  completely  and  rather 
suddenly.  The  well-known  case  of  the  sailor  who  suffered  for  more  than  a  year 
from  depressed  fracture  of  the  skull,  and  was  at  last  restored  to  his  normal  con- 
dition by  the  elevation  of  the  depressed  bone  (which  was  effected  by  Mr.  Cline), 
affords  another  illustration  of  the  same  suspension  of  cerebral  activity,  without 
the  loss  of  sensorial  power ;  this  man  passed  the  period  between  the  accident 
and  the  operation  in  a  condition  very  similar  to  that  of  the  subject  of  the  pre- 
ceding case;  and  after  his  recovery,  the  whole  intervening  space  was  a  perfect 
blank  to  his  recollection.  The  most  remarkable  example  of  this  condition, 
however,  yet  put  on  record,  is  a  case  which  occurred  a  few  years  ago  under  the 
observation  of  Mr.  Dunn,1  of  whose  excellent  account  an  abridgment  is  here 
given,  for  the  sake  of  illustrating  the  nature  of  a  purely  sensorial  arid  instinctive, 
as  distinguished  from  an  intelligent  existence,  and  the  gradual  nature  of  the 

1  "  Lancet,"  Nov.  15  and  29,  1845. 


838  OF  THE   JUNCTIONS   OF   THE   NERVOUS   SYSTEM. 

transition  from  the  one  to  the  other.1  A  very  similar  condition  presents  itself, 
as  the  result  of  the  complete  exhaustion  of  Cerebral  power,  in  those  extreme 
forms  of  Dementia,  or  rather  Amentia,  which  are  frequently  consequent  upon 

1  The  subject  of  this  case  -was  a  young  woman  of  robust  constitution  and  good  health, 
who  accidentally  fell  into  a  river  and  was  nearly  drowned.  She  remained  insensible  for 
six  hours  after  the  immersion  ;  but  recovered  so  far  as  to  be  able  to  give  some  account  of 
the  accident  and  of  her  subsequent  feelings,  though  she  continued  far  from  well.  Ten 
days  subsequently,  however,  she  was  seized  with  a  fit  of  complete  stupor,  which  lasted  for 
four  hours;  at  the  end  of  which  time  she  opened  her  eyes,  but  did  not  seem  to  recognize 
any  of  her  friends  around  her ;  and  she  appeared  to  be  utterly  deprived  of  the  senses  of 
hearing,  taste,  and  smell,  as  well  as  of  the  power  of  speech.  Her  mental  faculties  seemed 
to  be  entirely  suspended ;  her  only  medium  of  communication  with  the  external  world 
being  through  the  senses  of  sight  and  touch,  neither  of  which  appeared  to  arouse  ideas  in 
her  mind,  though  respondent  movements  of  various  kinds  were  excited  through  them.  Her 
^vision  at  short  distances  was  quick ;  and  so  great  was  the  exaltation  of  the  general  sensi- 
bility upon  the  surface  of  the  body,  that  the  slightest  touch  would  startle  her;  still,  unless 
she  was  touched,  or  an  object  or  a  person  was  so  placed  that  she  could  not  help  seeing  the 
one  or  the  other,  she  appeared  to  be  quite  lost  to  everything  that  was  passing  around  her. 
She  had  no  notion  that  she  was  at  home,  nor  the  least  knowledge  of  anything  about  her ; 
she  did  not  even  know  her  own  mother,  who  attended  upon  her  with  the  most  unwearied 
assiduity  and  kindness.  Wherever  she  was  placed,  there  she  remained  during  the  day. 
Her  appetite  was  good;  but  having  neither  taste  nor  smell,  she  ate  alike  indif- 
ferently whatever  she  was  fed  with,  and  took  nauseous  medicines  as  readily  as  delicious  viands. 
All  the  automatic  movements  unconnected  with  sensation,  of  which  the  spinal  cord  is  the 
instrument,  seemed  to  go  on  without  interference ;  as  did  also  those  dependent  upon  the 
sensations  of  sight  and  touch ;  whilst  the  functions  of  the  other  ganglia,  together  with 
those  of  the  cerebral  hemispheres,  appeared  to  be  in  complete  abeyance.  The  analysis  of 
the  facts  stated  regarding  her  ingestion  of  food  seems  to  make  this  clear.  She  swallowed 
food  when  it  was  put  into  her  mouth  ;  this  was  a  purely  automatic  action,  the  reception 
by  the  lips  being  probably  excited  by  sensation,  whilst  the  act  of  deglutition,  when  the 
food  is  carried  within  reach  of  the  pharyngeal  muscles,  is  excited  without  the  necessary 
concurrence  of  sensation.  She  made  no  spontaneous  effort,  however,  to  feed  herself  with 
the  spoon ;  showing  that  she  had  not  even  that  simple  idea  of  helping  herself,  which  in- 
fants so  early  acquire.  But  after  her  mother  had  conveyed  the  spoon  a  few  times  to  her 
mouth,  and  had  thus  caused  the  muscular  action  to  become  associated  with  the  sensorial 
stimulus,  the  patient  continued  the  operation.  It  appears,  however,  to  have  been  neces- 
sary to  repeat  this  lesson  on  every  occasion ;  showing  the  complete  absence  of  memory  for 
any  idea,  even  one  so  simple  and  so  immediately  connected  with  the  supply  of  the  bodily 
wants.  The  difference  between  an  instinct  and  a  desire  or  propensity,  heretofore  dwelt  on 
(g  772),  is  here  most  strikingly  manifested.  This  patient  had  an  instinctive  tendency  to 
ingest  food ;  as  is  shown  by  her  performance  of  the  actions  already  alluded  to  ;  but  these 
actions  required  the  stimulus  of  the  present  sensation,  and  do  not  seem  to  have  been  con- 
nected with  any  notion  of  the  character  of  the  object  as  food;  at  any  rate,  there  was  no 
manifestation  of  the  existence  of  any  such  notion  or  idea,  for  she  displayed  no  desire  for 
food  or  drink  in  the  absence  of  the  objects,  even  when  she  must  have  been  conscious  of 
the  uneasy  sensations  of  hunger  and  thirst.  The  very  limited  nature  of  her  faculties,  and 
the  automatic  life  she  was  leading,  appear  further  evident  from  the  following  particulars. 
One  of  her  first  acts  on  recovering  from  the  fit  had  been  to  busy  herself  in  picking  the 
bedclothes ;  and  as  soon  as  she  was  able  to  sit  up  and  be  dressed,  she  continued  the  habit 
by  incessantly  picking  some  portion  of  her  dress.  She  seemed  to  want  an  occupation  for 
her  fingers,  and  accordingly  part  of  an  old  straw  bonnet  was  given  to  her,  which  she 
pulled  to  pieces  of  great  minuteness  ;  she  was  afterwards  bountifully  supplied  with  roses ; 
she  picked  off  the  leaves,  and  then  tore  them  into  the  smallest  particles  imaginable.  A 
few  days  subsequently,  she  began  forming  upon  the  table,  out  of  these  minute  particles, 
rude  figures  of  roses  and  other  common  garden  flowers ;  she  had  never  received  any  in- 
structions in  drawing. — Roses  not  being  so  plentiful  in  London,  waste  paper  and  a  pair  of 
scissors  were  put  into  her  hands ;  and  for  some  days  she  found  an  occupation  in  cutting 
the  paper  into  shreds  ;  after  a  time  these  cuttings  assumed  rude  figures  and  shapes,  and 
more  particularly  the  shapes  used  in  patchwork.  At  length  she  was  supplied  with  pro- 
per materials  for  patchwork ;  and  after  some  initiatory  instruction,  she  took  to  her  needle 
and  to  this  employment  in  good  earnest.  She  now  labored  incessantly  at  patchwork  from 
morning  to  night,  and  on  Sundays  and  week-days,  for  she  knew  no  difference  of  days ;  nor 
could  she  be  made  to  comprehend  the  difference.  She  had  no  remembrance  from  day  to 
day  of  what  she  had  been  doing  on  the  previous  day,  and  so  every  morning  commenced 


GENERAL   RECAPITULATION,    PATHOLOGICAL  APPLICATIONS.     839 

repeated  attacks  of  Mania,  or  a  long  succession  of  Epileptic  seizures.  And  it 
is  also  worth  notice  that  the  "  picking  at  the  bedclothes/'  which  is  so  fre- 
quently seen  towards  the  close  of  life,  is  a  purely  consensual  movement,  the 

de  novo.  Whatever  she  began,  that  she  continued  to  work  at  while  daylight  lasted ;  mani- 
festing no  uneasiness  for  anything  to  eat  or  drink,  taking  not  the  slightest  heed  of  any- 
thing which  was  going  on  around  her,  but  intent  only  on  her  patchwork.  She  gradually 
began,  like  a  child,  to  register  ideas  and  acquire  experience.  This  was  first  shown  in 
connection  with  her  manual  occupation.  From  patchwork,  after  having  exhausted  all  the 
materials  within  her  reach,  she  was  led  to  the  higher  art  of  worsted-work,  by  which  her 
attention  was  soon  engrossed  as  constantly  as  it  had  before  been  by  her  humbler  employment. 
She  was  delighted  with  the  colors  and  the  flowers  upon  the  patterns  that  were  brought  to 
her,  and  seemed  to  derive  special  enjoyment  from  the  harmony  of  colors ;  nor  did  she  con- 
ceal her  want  of  respect  towards  any  specimen  of  work  that  was  placed  before  her,  but 
immediately  threw  it  aside  if  the  arrangement  displeased  her.  She  still  had  no  recollec- 
tion from  day  to  day  what  she  had  done,  and  every  morning  began  something  new,  unless 
her  unfinished  work  was  placed  before  her ;  and  after  imitating  the  patterns  of  others, 
she  began  devising  some  of  her  own.  The  first  ideas  derived  from  her  former  experience, 
that  seemed  to  be  awakened  within  her,  were  connected  with  two  subjects  which  had  natu- 
rally made  a  strong  impression  upon  her ;  namely,  her  fall  into  the  river,  and  a  love  affair. 
It  will  be  obvious  that  her  pleasure  in  the  symmetrical  arrangement  of  patterns,  the  har- 
mony of  colors,  &c.,  was  at  first  simply  sensorial ;  but  she  gradually  took  an  interest  in 
looking  at  pictures  or  prints,  more  especially  of  flowers,  trees  and  animals.  When,  how- 
ever, she  was  shown  a  landscape  in  which  there  was  a  river,  or  the  view  of  a  troubled  sea, 
she  became  intensely  excited  and  violently  agitated,  and  one  of  her  fits  of  spasmodic  rigid- 
ity and  insensibility  immediately  followed.  If  the  picture  were  removed  before  the  par- 
oxysm had  subsided,  she  manifested  no  recollection  of  what  had  taken  place ;  but  so  great 
was  the  feeling  of  dread  or  fright  associated  with  water,  that  the  mere  sight  of  it  in  mo- 
tion, its  mere  running  from  one  vessel  to  another,  made  her  shudder  and  tremble ;  and  in 
the  act  of  washing  her  hands  they  were  merely  placed  in  water.  From  this  it  may  be 
inferred  that  simple  ideas  were  now  being  formed  ;  for  whilst  the  actual  sight  or  contact 
of  moving  water  excited  them  by  the  direct  sensorial  channel,  the  sight  of  a  picture  contain- 
ing a  river  or  water  in  movement  could  only  do  so  by  giving  rise  to  the  notion  of  water. 
From  an  early  stage  of  her  illness  she  had  derived  evident  pleasure  from  the  proximity  of 
a  young  man,  to  whom  she  had  been  attached ;  he  was  evidently  an  object  of  interest  when 
nothing  else  would  rouse  her ;  and  nothing  seemed  to  give  her  so  much  pleasure  as  his 
presence.  He  came  regularly  every  evening  to  see  her,  and  she  as  regularly  looked  for 
his  coming.  At  a  time  when  she  did  not  remember  from  one  hour  to  another  what  she 
was  doing,  she  would  look  anxiously  for  the  opening  of  the  door  about  the  time  he  was 
accustomed  to  pay  her  a  visit ;  and  if  he  came  not,  she  was  fidgety  and  fretful  through- 
out the  evening.  When  by  her  removal  into  the  country  she  lost  sight  of  him  for  some 
time,  she  became  unhappy  and  irritable,  manifested  no  pleasure  in  anything,  and  suffered 
very  frequently  from  fits  of  spasmodic  rigidity  and  insensibility.  When,  on  the  other 
hand,  he  remained  constantly  near  her,  she  improved  in  bodily  health,  early  associations 
were  gradually  awakened,  and  her  intellectual  powers  and  memory  of  words  progressively 
returned.  We  here  see  very  clearly,  as  it  appears  to  us,  the  composite  nature  of  the  emo- 
tion of  affection.  At  first  there  was  simple  pleasure  in  the  presence  of  her  lover,  excited 
by  the  gratification  which  former  association  had  connected  with  the  sensation.  After- 
wards, however,  it  was  evident  that  the  pleasure  became  connected  with  the  idea ;  she 
thought  of  him  when  absent,  expected  his  return  (even  showing  a  power  of  measuring  time 
when  she  had  no  memory  for  anything  else),  and  manifested  discomfort  if  he  did  not  make 
his  appearance.  Here  we  see  the  true  emotion,  namely,  the  association  of  pleasure  with 
the  idea  ;  and  the  manner  in  which  the  desire  would  spring  out  of  it.  The  desire  in  her  then 
condition  would  be  inoperative  in  causing  voluntary  movement  for  its  gratification  ;  sim- 
ply because  there  was  no  intellect  for  it  to  act  upon.  Her  mental  powers,  however,  were 
gradually  returning.  She  took  greater  heed  of  the  objects  by  which  she  was  surrounded ; 
and  on  one  occasion,  seeing  her  mother  in  a  state  of  excessive  agitation  and  grief,  she 
became  excited  herself,  and  in  the  emotional  excitement  of  the  moment  suddenly  ejacu- 
lated, with  some  hesitation,  "What's  the  matter?"  From  this  time  she  began  to  articu- 
late a  few  words  ;  but  she  neither  called  persons  nor  things  by  their  right  names.  The 
pronoun  "  this"  was  her  favorite  word ;  and  it  was  applied  alike  to  every  individual  ob- 
ject, animate  and  inanimate.  The  first  objects  which  she  called  by  their  right  names  were 
wild  flowers,  for  which  she  had  shown  quite  a  passion  when  a  child  ;  and  it  is  remarkable 
that  her  interest  in  these  and  her  recollection  of  their  names  should  have  manifested  itself 
at  a  time  when  she  exhibited  not  the  least  recollection  of  the  "  old  familiar  friends  and 


840  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

performance  of  which  is  an  indication  of  the  torpor  that  has  supervened  upon 
the  functional  activity  of  the  Cerebrum. 

Xii.  It  is  the  Sensorium  that  is  primarily,  and  (it  may  be)  solely  affected, 
in  the  state  of  Coma  ;  which  differs  from  ordinary  sleep  only  in  the  complete- 
ness of  the  suspension  of  the  functional  activity  of  the  Sensory  Ganglia.  This 
suspension  not  merely  prevents  impressions  transmitted  from  the  organs  of 
sense,  from  affecting  the  consciousness  as  Sensations ;  but  it  also  interposes  the 
same  obstacle  to  that  mental  recognition  of  Cerebral  changes  which,  when  the 
Sensorium  is  closed  to  the  outer  world,  constitutes  the  state  of  Dreaming ;  and 
thus  the  comatose  subject  is  not  merely  insensible  to  external  impressions,  but 
is  cut  off  from  all  perception  of  self-existence.  There  seems  reason  to  believe 
that,  in  the  simpler  forms  of  Coma,  such  as  we  frequently  meet  with  in  hysteri- 
cal subjects,  there  is  no  perversion  of  the  functions  of  the  Cerebrum ;  for  we 
observe  that,  if  the  insensibility  suddenly  supervene  in  the  midst  of  a  sentence 
which  is  being  uttered  by  the  patient  (a  circumstance  of  no  uncommon  occur- 
rence), the  series  of  words  is  taken  up  and  completed  the  moment  that  the 
coma  passes  off,  the  patient  being  unconscious  of  the  interruption ;  showing 
that  there  is  none  of  that  confusion  of  the  Intellect  which  marks  Cerebral  dis- 
order. In  a  large  proportion  of  cases,  however,  it  is  obvious  from  the  order  in 
which  the  symptoms  manifest  themselves,  that  the  Cerebrum  is  affected  as  well 
as  the  Sensorial  centres ;  of  this  the  best  evidence  is  afforded  by  the  phenomena 
of  alcoholic  intoxication,  and  the  agency  of  narcotic  poisons ;  and  where  Coma 
results  from  pressure  within  the  cranium,  this  must  act  alike  upon  the  Cere- 
brum and  the  Sensorium.  Of  the  causes  which  induce  the  state  of  Coma,  there 
are  many  which,  when  operating  in  smaller  quantity,  or  in  less  intensity,  pro- 
duce delirium.  This  is  particularly  the  case  with  the  whole  group  of  truly  nar- 
cotic poisons;  and  is  not  merely  true  of  those  which  are  introduced  as  such  from 
external  sources,  but  also  with  regard  to  those  which  are  generated  within  the 

places"  of  her  childhood.  As  her  intellect  gradually  expanded,  and  her  ideas  became  more 
numerous  and  definite,  they  manifested  themselves  chiefly  in  the  form  of  emotions;  that 
is,  the  chief  indications  of  them  were  through  the  signs  of  pleasure  and  pain.  The  last 
were  frequently  exhibited  in  the  attacks  of  insensibility  and  spasmodic  rigidity,  which 
came  on  at  the  slightest  alarm.  It  is  worth  remarking  that  these  attacks  throughout  this 
remarkable  period,  were  apt  to  recur  three  or  four  times  a  day,  when  her  eyes  had  been 
long  directed  intently  upon  her  work  ;  which  affords  another  proof  how  closely  the  emo- 
tional cause  of  them  must  have  been  akin  to  the  influence  of  sensory  impressions,  the 
effects  of  the  two  being  precisely  the  same. — The  mode  of  recovery  of  this  patient  was 
quite  as  remarkable  as  anything  in  her  history.  Her  health  and  bodily  strength  seemed 
completely  re-established,  her  vocabulary  was  being  extended,  and  her  mental  capacity  was 
improving,  when  she  became  aware  that  her  lover  was  paying  attention  to  another  woman. 
This  idea  immediately  and  very  naturally  excited  the  emotion  of  jealousy  ;  which,  if  we 
analyze  it,  will  appear  to  be  nothing  else  than  a  painful  feeling  connected  with  the  idea  of 
the  faithlessness  of  the  object  beloved.  On  one  occasion  this  feeling  was  so  strongly  ex- 
cited, that  she  fell  down  in  a  fit  of  insensibility,  which  resembled  her  first  attack  in  dura- 
tion and  severity.  This,  however,  proved  sanitary.  When  the  insensibility  passed  off, 
she  was  no  longer  spellbound.  The  veil  of  oblivion  was  withdrawn ;  and,  as  if  awakening 
from  a  sleep  of  twelve  months'  duration,  she  found  herself  surrounded  by  her  grandfather, 
grandmother,  and  their  familiar  friends  and  acquaintances,  in  the  old  house  at  Shoreham. 
She  awoke  in  the  possession  of  her  natural  faculties  and  former  knowledge  ;  but  without 
the  slightest  remembrance  of  anything  which  had  taken  place  in  the  interval  from  the 
invasion  of  the  first  fit  up  to  the  present  time.  She  spoke,  but  she  heard  not ;  she  was 
still  deaf,  but,  as  she  could  read  and  write  as  formerly,  she  was  no  longer  cut  off  from 
communication  with  others.  /  From  this  time  she  rapidly  improved,  but  for  some  time  con- 
tinued deaf.  She  soon  perfectly  understood  by  the  motion  of  the  lips  what  her  mother 
said  ;  they  conversed  with  facility  and  quickness  together,  but  she  did  not  understand  the 
language  of  the  lips  of  a  stranger.  She  was  completely  unaware  of  the  change  in  her 
lover's  affections  which  had  taken  place  in  her  state  of  second  consciousness  ;  and  a  pain- 
ful explanation  was  necessary.  This,  however,  she  bore  very  well,  and  has  since  reco- 
vered her  previous  bodily  and  mental  health. 


GENERAL   RECAPITULATION,  PATHOLOGICAL   APPLICATIONS.     841 

body.  We  have  another  illustration  of  it  in  the  Coma  of  mere  exhaustion, 
which  is  frequently  preceded  by  delirium  that  is  clearly  attributable  to  nothing 
else  than  a  deficient  supply  of  blood.  Still  we  must  not  regard  Coma  as  always 
indicating  a  more  advanced  state  of  morbid  change  than  that  which  occasions 
Delirium ;  for  it  stands  to  some  forms  of  delirium  in  the  same  light  in  which 
ordinary  sleep  stands  to  the  waking  state,  being  the  repose  which  is  required 
for  reparation  after  a  state  of  excessive  mental  activity.  In  fact,  the  profound 
sleep  which  succeeds  a  protracted  period  of  severe  bodily  or  mental  exertion,  is 
often  almost  comatose,  as  regards  the  degree  in  which  the  subject  of  it  is  insen- 
sible to  external  stimuli.  The  same  may  be  stated  with  great  probability  of 
the  coma  which  is  consequent  upon  "  concussion'7  of  the  brain ;  for  this  may  be 
regarded  as  a  period  of  slow  regeneration,  during  which  the  effects  of  the  injury 
are  being  repaired  by  the  nutritive  processes  j  and  any  attempt  to  arouse  the 
patient  prematurely  is  far  more  likely  to  be  injurious  than  beneficial,  tending 
especially  to  increase  the  violence  of  the  subsequent  reaction. 

xin.  It  is,  as  we  have  seen,  in  the  Sensorial  centres,  that  those  lesions  are 
most  commonly  found,  which  give  rise  to  hemiplegic  Paralysis.  There  can  be 
little  doubt  that  this  form  of  paralysis  is  usually  attributable  to  some  structural 
disorganization  of  the  nervous  substance,  produced  by  hemorrhage,  softening, 
&c.  Still  this,  like  other  forms  of  partial  paralysis,  may  be  toxic,  depending 
rather  upon  the  condition  of  the  blood  than  upon  that  of  the  nervous  tissue. 
Of  such  toxic  influence,  we  have  a  remarkable  example  in  the  peculiar  local 
paralysis  induced  by  the  presence  of  Lead  in  the  system ;  and  there  seems  much 
reason  to  believe  that  some  of  the  Hysterical  forms  of  paralysis  (as  well  as  of 
convulsive  disorders)  are  of  toxic  origin.  There  are  many  instances,  too,  in 
which  paralysis,  like  convulsion,  seems  to  depend  upon  some  injurious  influence 
propagated  from  the  nerves  of  some  other  part. — Although  it  is  in  Hemiplegia 
that  we  have  the  most  distinct  evidence  of  disorder  of  the  Encephalic  centres, 
yet  paralysis  of  any  one  part  of  the  body  may  proceed  from  Encephalic  lesion ; 
and  even  some  forms  of  Paraplegia  seem  traceable  to  disorders  of  the  Cerebrum 
and  Sensory  Ganglia.1 

xiv.  We  seem  entitled  to  consider  the  Sensory  Ganglia  as  the  primary  seat 
of  that  combination  of  loss  of  sensibility,  with  spasmodic  movements,  which 
essentially  constitutes  Epilepsy.  This  is  marked  by  the  peculiar  sensorial  phe-; 
nomena  which  usually  precede  the  paroxysm ;  by  the  obliteration  of  consciousness, 
which  is  its  prominent  symptom;  and  by  the  peculiarity  of  the  spasmodic  contrac- 
tions, which  are  donic  (or  alternating  with  relaxation)  instead  of  being  tonic  (or 
persistent),  and  which  correspond  with  those  that  may  be  induced  by  artificial 
stimulation  of  this  portion  of  the  Encephalic  centres  (§  738).  The  disordered 
action,  however,  manifestly  extends  itself  to  the  Cerebrum ;  for  a  maniacal 
paroxysm  frequently  occurs  in  connection  with  the  epileptic  attacks ;  the  attacks 
themselves  are  sometimes  preceded,  and  very  commonly  followed,  by  consider- 
able confusion  of  the  intellect;  the  disease  is  seldom  long  persistent  without  im- 
pairing the  memory  and  the  control  of  the  will  over  the  mental  operations;  and 
in  cases  of  long  standing,  the  power  of  the  Cerebrum  appears  to  be  almost 
entirely  destroyed.  There  is  very  considerable  diversity,  on  the  other  hand,  in 
regard  to  the  nature  and  intensity  of  the  muscular  convulsion  ;  and  there  seems 
reason  to  think  that  when  the  morbid  influence  is  determined  downwards  into 
the  Motor  apparatus,  the  Cerebrum  escapes  with  a  less  serious  impairment  of 
its  powers,  since  the  destruction  of  the  intellectual  power  occurs  more  surely 
where  the  fits  are  accompanied  by  much  mental  disturbance  or  stupor,  than 
where  the  convulsive  character  predominates. — One  of  the  most  remarkable 

1  For  much  valuable  information  on  the  different  forms  of  Paralysis,  see  Dr.  Gull's 
Gulstonian  Lectures  "On  the  Nervous  System"  in  the  "Medical  Times,"  1849. 


842  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

phenomena  of  Epilepsy  is  its  tendency  to  periodic  recurrence,  with  a  more  or 
less  complete  return  to  the  normal  state  in  the  interval.  This  fact  of  itself 
seems  to  indicate  that  the  disease  cannot  be  fairly  attributed  to  those  obvious 
lesions  of  structure  which  are  sometimes  coincident  with  it,  and  which,  as  Dr. 
Todd  has  justly  remarked,  are  rather  the  signs  of  the  altered  nutrition  brought 
on  by  any  cause  which  creates  frequent  disturbance  of  the  actions  of  the  brain, 
than  the  causes  of  that  disturbance ;  for  the  influence  of  such  lesions,  if  mani- 
fested at  all  (and  it  is  remarkable  what  an  extent  of  disorganization  may  take 
place  without  any  obvious  indication),  would  be  rather  continuous  than  inter- 
mitting. It  is  quite  certain,  on  the  other  hand,  that  death  "may  occur  from 
Epilepsy,  without  any  appreciable  lesion.  It  may  be  considered,  also,  as  a  well- 
established  fact,  that  the  epileptic  paroxysm  may  be  induced  either  by  an  in- 
sufficient supply,  or  by  depravation  of  blood ;  of  this  we  have  examples  in  the 
epileptiform  convulsions  brought  on  by  excessive  hemorrhage  in  parturient 
women,  in  the  epileptiform  paroxysm  induced  by  asphyxia  (especially  by  strangu- 
lation), and  in  poisoning  by  hydrocyanic  acid,  the  phenomena  of  which,  in  the 
lower  animals  especially,  so  closely  simulate  those  of  the  genuine  disease,  that 
they  may  be  designated  as  an  artificial  epilepsy.  These  and  many  other  facts 
in  the  etiology  of  the  disease  very  strongly  point  to  a  disordered  condition  of 
the  blood  as  its  primal  source  j  this  acting  either  by  altering  the  nutrition  of 
the  Encephalic  centres,  or  by  perverting  their  action,  or  in  both  modes  conjointly, 
as  in  the  case  of  Insanity  (vin.).  According  to  the  theory  advocated  by  Dr. 
Todd,  a  continual  mal-nutrition  of  certain  parts  of  the  Encephalon  occasions  a 
gradually  increasing  disturbance  of  their  polar  state  j  and  this,  when  it  has 
attained  a  certain  measure  of  intensity,  manifests  itself  in  the  epileptic  parox- 
ysm, just  as  a  Leyden  jar,  when  charged  with  electricity  to  a  certain  state  of 
tension,  gets  rid  of  the  disturbance  of  equilibrium  by  the  "disruptive  discharge/'1 
The  fact  must  not  be  disregarded,  however,  that  when  a  state  of  mal-nutrition 
of  the  Nervous  System  has  been  established  by  causes  which  affect  the  condition 
of  the  Blood,  the  Epileptic  paroxysm  may  be  induced  by  some  excentric  or  pe- 
ripheral irritation,  such  as  worms  in  the  intestinal  canal,  the  pressure  of  teeth  in 
the  eruptive  stage  of  development  against  the  capsule  or  the  gum,  &c. ;  neither 
cause  being  sufficient  when  acting  alone.  Hence,  although  the  paroxysms  may 
be  suspended  and  the  disease  apparently  cured,  by  the  removal  of  the  peripheral 
source  of  irritation  (as  by  the  expulsion  of  the  worms,  or  the  complete  erup- 
tion of  the  teeth),  the  liability  to  it  still  remains,  as  is  shown  by  the  renewal 
of  the  paroxysms  whenever  any  fresh  irritation  may  arise.  It  is  very  import- 
ant, therefore,  not  to  rest  satisfied  with  local  treatment  in  such  cases ;  but  to 
have  recourse  to  measures  adapted  to  produce  a  general  invigoration  of  the 
system.3 

XV.  The  Spinal  Axis  (including  the  Medulla  Oblongata)  forms  a  continuous 
series  of  ganglionic  centres,  which  are  connected  by  afferent  and  efferent  nerve- 
trunks  with  the  several  segments  of  the  body ;  but  these  centres  are  enveloped 
in  white  or  fibrous  strands,  which  not  only  connect  the  various  segmental  divi- 
sions with  each  other,  but  also,  there  seems  good  reason  to  believe,  establish  a 
continuous  connection  between  the  Nerve-roots  and  the  Sensorial  centres.  The 
independent  activity  of  the  Spinal  centres  is  seen  in  the  various  reflex  move- 
ments which  are  performed  after  they  have  been  cut  off  from  all  connection  with 

1  See  Dr.  Todd's  "Lumleian  Lectures"  in  the  ''Medical  Gazette,"  May  18,  1849;  and 
the  "Brit,  and  For.  Med.  Chir.  Rev.,"  Jan.  1850,  pp.  24—33. 

2  The  Author  does  not  think  it  necessary  here  to  devote  any  space  to  the  examination 
of  Dr.  M.  Hall's  pathological  theory  of  Epilepsy,  which  makes  it  depend  upon  spasmodic 
compression  of  certain  muscles  of  the  neck,  producing  compression  of  the  veins  and  con- 
gestion of  the  cerebrum ;  since  he  considers  that  the  fallacies  of  this  theory  have  been 
already  sufficiently  pointed  out  by  Dr.  Todd  (loc.  cit.). 


GENERAL  RECAPITULATIO  N3   PATHOLOGICAL   APPLICATIONS.    843 

the  Encephalon;  and  of  these  reflex  movements,  there  are  certain  definite  groups, 
which  are  subservient  to  the  functions  of  Respiration,  Deglutition,  Defecation, 
&c.  In  so  far  as  these  are  performed  by  the  Spinal  Cord  alone,  without  the 
participation  of  the  Sensorium,  they  do  not  involve  any  affection  of  the  con- 
sciousness; and,  as  the  separation  of  the  Spinal  Cord  from  the  Sensorium 
effectually  prevents  the  impression  which  excites  the  reflex  movement  from 
exciting  sensation  at  the  same  time,  we  know  that  sensation  cannot  be  necessary 
to  the  movement ;  hence  this  class  of  actions  is  best  distinguished  as  excito- 
motor,  in  contradistinction  to  the  sensor -i-motor,  in  which  Sensation  necessarily 
participates.  Putting  aside,  however,  those  actions  which  are  subservient  to 
the  Organic  functions,  and  which  are  performed  in  the  state  of  full  integrity 
and  activity  of  the  nervous  system,  we  find  that  the  reflex  power  of  the  Spinal 
Cord  is  only  distinctly  manifested  when  that  organ  is  detached  from  the  Ence- 
phalon ;  for  in  its  normal  state  it  serves  as  little  else  than  the  channel  through 
which  impressions  are  transmitted  upwards  to  the  Sensorium,  and  thence  to  the 
Cerebrum,  and  through  which  motor  impulses  are  propagated  downwards  from 
these  centres  to  the  muscles.  For  the  actions  of  the  Spinal  Cord  are  placed  in 
subordination  to  the  control  of  the  Cerebrum,  in  every  particular  as  to  which 
they  can  be,  without  detriment  to  the  welfare  of  the  system  generally;  so  that 
we  find  excitor  impressions,  which  are  quite  competent  to  evoke  reflex  actions 
if  they  are  prevented  from  travelling  beyond  the  Cord,  losing  their  power  to  do 
so  when  they  are  discharged  (so  to  speak)  into  the  Sensorium ;  whilst  even  the 
movements  of  Respiration,  Defecation,  &c.,  which  do  not  require  the  participa- 
tion of  the  Cerebrum,  in  their  ordinary  performance,  can  be  to  a  certain  extent 
controlled  by  the  "Will. 

XVI.  In  the  various  classes  of  Convulsive  diseases  in  which  the  conscious- 
ness is  not  affected,  we  have  manifestations  of  the  perverted  activity  of  the 
Spinal  Cord  as  a  whole,  or  of  certain  of  its  segments. — Of  the  distinct  forms 
or  combinations  of  which  this  class  of  disorders  is  composed,  Tetanus  is  one  of 
the  most  interesting  and  instructive.  This  disease  essentially  consists  in  an 
undue  excitability  of  the  whole  series  of  Spinal  Ganglia  ;  so  that  very  slight 
impressions  produce  violent  and  extensive  reflex  actions,  the  disturbance  of  nerv- 
ous polarity  induced  by  the  impression,  radiating  (as  it  were)  through  the 
whole  Cord,  and  affecting  nerve-fibres  that  proceed  from  each  of  its  different 
segments ;  and  when  this  state  is  fully  established,  convulsive  actions  may  pro- 
ceed from  purely  centric  irritation,  no  excitor  impression  being  required  to  ori- 
ginate them.  Such  a  state  may  be  induced  by  various  causes,  among  the  most 
prominent  of  which  are,  on  the  one  hand,  those  which  affect  the  nutrition  of 
the  Cord,  and,  on  the  other,  those  which  call  it  into  disordered  action,  by  alter- 
ing the  relations  which  the  blood  bears  to  it  as  the  exciting  fluid  of  the  nervous 
battery.  That  which  is  termed  the  idiopathic  form  of  the  disease  seems  trace- 
able to  mal-nutrition  of  the  Cord,  consequent  upon  impoverishment  or  deprava- 
tion of  the  blood  ;  that,  on  the  other  hand,  which  is  produced  by  the  intro- 
duction of  Strychnia  into  the  blood,  is  dependent  upon  the  peculiar  potency  of 
this  substance  in  determining  a  wrong  action  of  the  Spinal  centres,  for  which  it 
seems  to  have  an  elective  affinity,  in  the  same  way  that  alcohol  and  opium  have 
for  the  encephalic.  With  regard  to  the  traumatic  form  of  Tetanus,  it  is  im- 
possible to  say  with  certainty  whether  the  peculiar  condition  of  the  Spinal  Cord 
be  determined,  as  in  the  preceding  case,  by  the  introduction  of  a  poison  into 
the  blood,  through  some  morbid  action  taking  place  in  the  wound ;  or  whether 
the  disturbance  of  the  usual  equilibrium  be  consequent  upon  the  propagation  of 
a  morbid  influence  directly  from  the  injured  nerve-trunk  to  the  Spinal  centres, 
without  any  participation  of  the  Circulating  System  in  this  extension  of  the 
mischief.  Whichever  be  the  true  account  of  it,  this  much  is  certain,  that  when 
the  Tetanic  state  of  the  Spinal  Cord  is  once  fully  established,  nothing  is  gained 


844  OF   THE   FUNCTIONS   OF   THE   NERVOUS    SYSTEM. 

by  removal  of  the  injured  part ;  and  powerful  sedative  remedies  alone  possess 
any  influence  in  restraining  the  paroxysms.  The  Cerebral  apparatus  is  entirely 
unaffected  in  this  disorder ;  but  the  nerves  of  deglutition  are  usually  those  first 
influenced  by  it ;  those  of  respiration,  however,  being  soon  affected,  as  also 
those  of  the  trunk  in  general. — The  condition  termed  Hydrophobia  is  nearly 
allied  to  that  of  traumatic  Tetanus,  differing  chiefly  in  the  mode  in  which  the 
cranio-spinal  axis  is  affected.  The  irritable  state  of  the  nervous  centres  obvi- 
ously results  from  the  introduction  of  a  poison  into  the  blood ;  and  here  the 
early  removal  of  the  wounded  part  is  very,  desirable  as  a  means  of  prevention ; 
although,  when  the  poison  has  once  begun  to  operate  on  the  centres,  it  is  of  no 
use.  The  muscles  of  respiration  and  deglutition  are,  as  in  Tetanus,  those  spas- 
modically affected  in  the  first  instance ;  but  there  is  this  curious  difference  in 
the  mode  in  which  they  are  excited  to  action — that,  whilst  in  Tetanus  the 
stimulus  operates  through  the  Spinal  Cord  (either  centrally,  or  by  being  con- 
veyed from  the  periphery),  in  Hydrophobia  it  is  often  transmitted  from  the 
ganglia  of  Special  Sense,  or  even  from  the  Cerebrum;  so  that  the  sight  or 
sound  of  fluids,  or  even  the  idea  of  them,  occasions — equally  with  their  contact, 
or  with  that  of  a  current  of  air — the  most  distressing  convulsions. — Many 
forms  of  that  protean  malady,  Hysteria,  are  attended  with  a  similar  irritability 
of  the  Nervous  Centres;  but  there  is  this  remarkable  difference  in  the  two 
cases,  that  the  morbid  phenomena  of  Hysteria,  whilst  they  often  simulate  those 
of  Chorea,  Tetanus,  Hydrophobia,  Epilepsy,  &c.,  are  evidently  dependent  upon 
a  state  of  the  system  of  a  much  less  abnormal  character.  The  absence  of  any 
structural  lesion,  and  even  of  any  serious  impairment  of  the  nutrition,  of  the 
parts  of  the  Nervous  System  which  are  the  sources  of  the  actions  in  question, 
is  proved  by  the  length  of  time  during  which  the  severest  forms  of  them  may 
exist  without  permanently  serious  consequences,  and  by  the  suddenness  with 
which  the  several  forms  of  them  give  place  one  to  another,  or  pass  off  alto- 
gether. The  strange  combinations,  moreover,  which  they  occasionally  present, 
remarkably  distinguish  them  from  the  more  settled  forms  of  the  diseases  which 
they  simulate.1  The  clinical  history  of  Hysteria,  then,  would  lead  us  to  sup- 

1  Thus,  the  Author  has  known  an  obstinate  case  of  Hysteric  disorder,  in  which  at  one 
period  attacks  of  the  most  complete  Opisthotonos  coexisted  with  perfect  Coma;  at  another 
period,  the  Coma  recurred  alone  ;  then  again,  there  was  Trismus,  lasting  for  five  conse- 
cutive days,  without  any  other  spasmodic  action  or  loss  of  sensibility ;  this  sometimes 
alternated  with  fits  of  Yawning,  in  which  the  jaw  was  held  open  for  half  an  hour  together; 
at  another  period,  the  convulsions  had  more  of  the  Epileptic  character,  the  face  being  dis- 
torted, and  the  limbs  agitated,  concurrently  with  a  state  of  Coma,  but  without  laryn- 
gismus ;  with  this  alternated  fits  of  Laryngismus,  without  insensibility,  and  occurring 
during  the  expiratory  movement ;  whilst  during  the  whole  of  this  succession,  there  was 
Paralysis  of  the  extensor  muscles  of  both  lower  extremities,  with  paroxysms  of  the  most 
violent  and  prolonged  Cramp  in  one  of  them.  (See  g  325,  note.)  The  mental  phenomena 
were  almost  equally  strange  ;  for  a  state  of  almost  Maniacal  excitement  often  came  on  sud- 
denly, and  ceased  no  less  abruptly  ;  and  every  form  of  double  consciousness,  from  simple 
sleep-waking  to  an  alternation  of  two  very  similar  states  of  mental  existence,  presented 
itself  during  one  long  period  of  the  disorder. — It  is  worth  noting  that  in  this  case  the 
exciting  cause  of  the  disorder  lay  in  the  disappointment  of  affections  long  cherished  in 
secret ;  but  the  nutrition  of  the  nervous  system  had  been  previously  impaired  by  anxiety 
and  excessive  mental  exertion.  The  first  access  of  the  disorder  was  kept  off  by  the  influ- 
ence of  a  very  determined  will ;  but  when  the  malady  had  fully  developed  itself,  it  resisted 
every  kind  of  treatment  for  four  years.  The  catamenial  discharge  remained  very  scanty 
during  the  whole  of  that  time,  and  was  sometimes  absent  altogether ;  and  the  recurrence 
of  the  period  was  almost  invariably  marked  by  an  aggravation  of  the  spasmodic  attacks, 
and  frequently  by  pains  resembling  those  of  the  first  stage  of  labor.  A  slow  and  almost 
imperceptible  improvement  was  taking  place,  when  circumstances  occurred,  which  gave  a 
new  turn  to  the  feelings ;  a  fresh  attachment  was  formed,  which  was  happily  reciprocated; 
and  from  that  time  the  cure  rapidly  advanced,  the  convulsive  and  paraplegic  affections 
being  speedily  recovered  from,  and  nothing  being  left  but  dysmeiiorrhoea,  which  still  con- 


GENERAL   RECAPITULATION,   PATHOLOGICAL   APPLICATIONS.     845 

pose  that  the  convulsive  action  depends  rather  upon  some  state  of  the  blood 
which  alters  its  relation  to  the  nervous  tissue  as  its  exciting  fluid,  than  upon 
any  such  change  in  the  nutritive  supply  which  it  affords  as  would  induce  a 
more  permanent  disorder  in  the  system.  Taking  all  the  phenomena,  however, 
into  account,  there  seems  much  reason  to  think  that  a  general  excitability  of 
the  nervous  system,  such  as  is  only  an  exaggeration  of  that  which  is  character- 
istic of  the  female  sex,  is  induced  by  some  defect  of  Nutrition,  comparatively 
permanent  in  its  nature  ;  whilst  the  particular  forms  of  perverted  action  are 
determined  either  by  some  toxic  agent  in  the  blood,  slight  variations  in  which 
may  give  it  a  selective  power  for  one  part  or  another  of  the  Nervous  Centres,  or 
by  irritation  of  the  peripheral  nerves.  Among  the  sources  of  imperfect  nutri- 
tion, leading  to  undue  excitability  of  the  nervous  system,  and  thus  acting  as  a 
"  predisposing  cause,"  it  seems  probable  that  a  gouty  diathesis  is  one  of  the 
most  frequent  j1  whilst  among  the  exciting  causes,  some  irregular  action  of  the 
sexual  apparatus  is  among  the  most  common,  though  it  would  not  be  correct  to 
affirm,  that  disorder  of  the  nutritive  or  secretory  functions  of  the  sexual  system 
is  essential  to  the  production  of  the  hysteric  condition.  The  influence  of  Emo- 
tional states  upon  this  condition  is  among  the  most  remarkable  features  in  the 
history  of  the  disorder.  There  can  be  little  doubt  that  habitual  indulgence  of 
the  feelings,  especially  when  these  are  of  a  painful  kind,  has  a  direct  tendency  to 
affect  the  nutrition  of  the  nervous  system  ;  but  when  these  feelings  have  special 
reference  to  sexual  subjects,  they  will  exert  a  powerful  indirect  influence,  by 
fixing  the  mind  on  the  genital  system,  and  thereby  modifying  its  condition 
(CHAP,  xviii.).  In  either  of  these  modes,  the  habitual  emotional  state  acts  as 
a  "  predisposing  cause ;"  but  we  constantly  observe  that,  when  the  hysteric 
diathesis  is  established,  any  particular  access  of  emotional  excitement,  even 
though  it  be  of  a  pleasurable  nature,  induces  the  hysteric  paroxysm ;  and  it  is 
by  making  a  powerful  effort  to  restrain  the  feelings  that  the  Will,  if  the  patient 
can  be  led  to  exert  it,  has  so  much  control  over  the  hysterical  tendency.  It 
is  generally,  however,  a  part  of  the  complaint,  that  the  Will  cannot  be  effectually 
exerted;  and  this  either  on  account  of  the  vehemence  of  the  Emotional  dis- 
turbance, or  through  an  absolute  impairment  of  voluntary  power;  the  state  of 
mind  then  approximating  closely  to  some  forms  of  Insanity.  It  is  in  such  cir- 
cumstances that  the  influence  of  powerful  motives,  adapted  to  work  upon  the 
Will  through  the  feelings,  may  be  brought  to  bear  most  effectually  in  checking 
the  paroxysm ;  thus  it  is  well  known  that  when  the  sight  of  an  "  hysteric  fit" 
in  one  individual  tends  to  induce  it  in  another,  a  determined  threat  of  severe 
treatment  is  the  most  certain  means  of  keeping  it  off. — Hence  the  treatment  of 
Hysteria  may  be  considered  as  requiring  three  classes  of  remedial  means ; — 
those,  namely,  which  operate  by  improving  the  general  state  of  nutrition  of  the 
Nervous  System  and  by  diminishing  its  excitability,  these  for  the  most  part 
acting  through  the  blood,  and  being  directed  to  the  increase  of  its  nutritive  com- 
ponents and  to  the  elimination  of  any  morbid  matter  which  it  may  be  suspected 
to  contain;  those  which  operate  by  removing  the  exciting  causes  of  the 

tinned  to  be  occasionally  accompanied  by  severe  cramps,  and  sometimes  by  general  con- 
vulsion, coma,  &c.  This  was  not  altogether  corrected,  although  improved  by  marriage  ; 
and  any  emotional  excitement  of  an  unpleasant  kind  was  sure  to  produce  an  additional 
aggravation.  The  state  of  the  os  uteri  was  then  examined;  and  as  it  was  found  to  be  un- 
duly contracted,  cautious  dilatation  by  sponge-tents  was  practised.  This  had  the  best 
results  ;  the  dysmenorrhoea  soon  abated;  pregnancy  supervened,  and  after  a  miscarriage 
(which  seemed  traceable  to  emotional  excitement,  coinciding  with  the  monthly  nisus)  a 
second  pregnancy,  which  went  on  to  the  full  term  ;  and  no  return  of  the  spasmodic  attacks 
has  since  occurred. — It  is  worthy  of  note  that  in  this  case  there  was  an  hereditary  predis- 
position to  Gout,  which  seemed  once  to  manifest  itself  in  a  peculiar  affection  of  the  tis- 
sues about  the  wrist-joint,  of  a  character  rather  gouty  than  rheumatic. 
1  See  Dr.  Laycock  "On  the  Nervous  Diseases  of  Women,"  pp.  161  et  seq. 


846  OF   THE   FUNCTIONS    OF   THE   NERVOUS    SYSTEM. 

paroxysm,  among  which  may  be  specially  reckoned  all  such  as  promote  the 
healthful  performance  of  the  menstrual  function  ;  and,  lastly,  all  those  which  act 
beneficially  on  the  Mind,  diverting  or  repressing  painful  emotions,  or  substitut- 
ing pleasurable  feelings  in  their  place,  and  strengthening  the  general  control  of 
the  Will. 

xvu.  The  foregoing  are  the  chief  Convulsive  diseases  in  which  the  Spinal 
centres  generally  are  involved ;  but  there  are  many  spasmodic  affections  of  a 
more  limited  character,  which  are  traceable  to  a  morbid  affection  of  some  parti- 
cular division  of  the  Spinal  Axis.  Thus  in  the  various  forms  of  Spasmodic 
Asthma,  the  Medulla  Oblongata  would  seem  to  be  alone  involved ;  the  attacks 
of  this  disorder  usually  resulting  from  some  internal  irritation,  either  in  the  air- 
passages  themselves,  or  in  the  digestive  system,  producing  a  reflex  contraction 
of  the  muscular  fibres  of  the  bronchial  tubes.  In  the  purely  spasmodic  stage  of 
Hooping- Cough,  again,  which  frequently  persists  long  after  all  inflammatory 
symptoms  have  subsided,  we  have  another  example  of  spasmodic  action  limited 
to  the  respiratory  centres ;  and  here  we  have  distinct  evidence  that  the  morbid 
condition  originates  in  the  introduction  of  a  poison  into  the  blood.  The  same 
may  be  said  of  the  Croup-like  Convulsion  or  Crowing  Inspiration  of  Infants, 
which  is  an  obstruction  to  the  passage  of  air  through  the  Glottis,  produced 
by  a  spasmodic  contraction  of  the  constrictors  of  the  larynx;  for,  although 
the  spasmodic  action  may  be  immediately  brought  on  by  various  kinds  of 
local  irritation,  such  as  that  occasioned  by  teething,  by  the  presence  of  undi- 
gested food,  or  by  intestinal  disorder,  yet  there  is  no  doubt  that  the  excitable 
condition  of  the  Nervous  Centres,  without  which  these  influences  would  be  in- 
operative, is  dependent  upon  a  defect  of  nutrition  arising  from  unwholesome  food, 
bad  air,  or  some  other  cause  affecting  the  system  generally.1 — Spasmodic  closure 
of  the  Larynx  may  occur  from  other  causes.  When  the  rima  glottidis  is  nar- 
rowed, by  effusion  of  fluid  into  the  substance  of  its  walls,  it  is  very  liable  to  be 
completely  closed  by  spasmodic  action,  to  which  the  unduly  irritable  condition 
of  the  mucous  membrane  will  furnish  many  sources  of  excitement.  Choking, 
again,  does  not  result  so  much  from  the  pressure  of  the  food  on  the  air-passages 
themselves,  as  from  the  spasmodic  action  of  the  larynx  excited  by  this  ;  and  the 
dislodgment  of  the  morsel  by  an  act  of  vomiting  is  the  most  effectual  means 
of  obtaining  relief. — Tenesmus  and  Strangury  are  well-known  forms  of  spas- 
modic muscular  contraction,  excited  by  local  irritation  acting  through  the  Spinal 
centres.  The  abnormal  action  which  leads  to  Abortion  (CHAP,  xix.)  is  fre- 
quently excited  in  the  same  manner. — There  is  a  form  of  Incontinence  of  Urine, 
which  is  very  analogous  to  the  morbid  action  just  described;  the  sphincter  has 
its  due  power;  but  the  stimulus  to  the  evacuation  of  the  bladder  is  excessive  in 
strength  and  degree,  owing  to  the  acridity  of  the  urine  or  other  causes.  The 
part  of  the  bladder  upon  which  this  appears  chiefly  to  act  is  the  trigonum  (which 
is  well  known  to  be  more  sensitive  to  the  irritation  of  calculi  than  the  rest  of 
the  internal  surface) ;  and  Sir  C.  Bell  advises  young  persons  who  suffer  during 
the  night  from  this  very  disagreeable  complaint,  to  lie  upon  the  belly  instead  of 
the  back,  so  that  the  contact  of  the  urine  with  the  trigonum  may  be  delayed  as 
long  as  possible. 

xvni.  As  convulsive  diseases  are  dependent  upon  excessive  activity  of  the 
Spinal  centres,  so  do  various  forms  of  Paralysis  arise  from  disease  of  the  Cord, 
affecting  its  proper  ganglionic  substance,  or  the  connections  of  its  nerve-roots 
with  the  Encephalon.  If  the  latter  only  be  impaired,  we  have  an  interruption  of 
sensibility  and  voluntary  motion,  the  reflex  actions  of  the  Spinal  ganglia  being 

1  The  influence  of  "  change  of  air"  is  often  as  marked  in  this  disease,  as  it  is  in  the 
chronic  stage  of  hooping-cough.  That  an  impure  atmosphere  is  of  itself  sufficient  to  induce 
fatal  convulsive  disorders  in  infants,  has  been  sufficiently  proved  on  a  former  occasion 
(2  683). 


GENERAL  RECAPITULATION,    PHYSIOLOGICAL   APPLICATIONS.    847 

still  manifested ;  but  if  the  former  be  involved,  these  reflex  actions  are  suspended 
no  less  completely  than  are  the  sensori-volitional.  There  are  many  peculiar 
phenomena  of  Paralysis  depending  on  Spinal  lesion,  however,  which  have  not 
yet  been  explained  on  any  physiological  basis.  Among  these  is  the  fact,  to 
which  Dr.  Gull  has  prominently  directed  attention,1  that  in  Paraplegia  dependent 
upon  lesion  of  the  Cord,  there  is  usually  greater  loss  of  motion  than  of  sensation  j 
whilst  in  Paraplegia  dependent  upon  Encephalic  disorder,  or  upon  toxic  agencies 
rather  affecting  the  peripheral  than  the  central  portions  of  the  nervous  system 
(as  seems  to  be  generally  the  case,  for  example,  in  poisoning  by  lead),  affections 
of  the  sensibility  sometimes  beginning  with  hyperaesthesia  and  then  proceeding 
to  more  or  less  complete  anaesthesia,  usually  constitute  the  prominent  symptoms. 

xix.  Our  present  knowledge  of  the  Physiology  and  Pathology  of  the  Cere- 
bellum seems  to  justify  the  inference,  that  its  special  function  consists  in  the 
co-ordination  of  voluntary  movements;  and  the  effects  of  lesions  whose  influence 
is  limited  to  this  organ  display  themselves  most  constantly  in  the  impairment 
of  this  power. — But  there  are  pathological  phenomena  which  seem  to  indicate 
that  a  centre  of  sexual  sensation  has  its  place  in  or  near  the  central  lobe  of  the 
Cerebellum,  and  that,  according  to  the  degree  of  excitement  or  of  depression  of 
its  functional  activity,  will  be  the  strength  or  weakness  of  the  sexual  desire 
prompted  by  the  sensation. 

xx.  Of  the  morbid  affections  of  the  Sympathetic  System,  it  is  impossible  to 
state  anything  with  precision,  in  our  present  state  of  almost  complete  ignorance 
of  its  physiological  actions.  It  may  be  stated,  however,  as  an  indubitable  fact, 
that,  in  virtue  of  the  afferent  Cerebro-spinal  fibres  which  it  contains,  it  may 
receive  impressions  from  morbid  states  of  the  organs  which  it  supplies,  and  may 
transmit  these  to  the  Spinal  cord ;  through  which,  general  convulsive  move- 
ments, or  irregular  actions  of  the  Sensorial  or  even  of  the  Cerebral  centres,  may 
be  excited.  Of  this  we  have  an  example  in  the  erratic  phenomena  of  Hysteria 
already  referred  to. 

[In  the  foregoing  view  of  the  Functions  of  the  Nervous  System,  the  Author  has  endea- 
vored to  exhibit  this  most  difficult  and  in  many  parts  obscure  subject,  under  the  aspect  in 
which  it  now  presents  itself  to  his  own  mind:  believing  that  he  could  thus  best  explain  it 
to  his  readers.  As  his  views  have  been  arrived  at  by  his  own  careful  study  of  the  sub- 
ject, he  has  not  thought  it  necessary  to  be  continually  referring  to  other  Physiologists, 
with  whose  doctrines  his  own  may  have  more  or  less  of  coincidence.  He  would  here  state, 
once  for  all,  that  of  the  older  writers  on  this  branch  of  Physiology,  he  regards  Unzer 
and  Prochaska  (whose  treatises  have  been  lately  republished  by  the  Sydenham  Society)  as 
having  displayed  the  deepest  insight  into  the  truth ;  their  doctrines  requiring  little  more 
than  the  correction  and  extension  which  subsequent  anatomical  discoveries  have  afforded, 
to  form  part  of  the  present  fabric  of  the  science.  And  he  considers  it  as  no  unimportant 
confirmation  of  his  own  views  that,  although  arrived  at  in  complete  ignorance  of  what  Unzer 
had  long  previously  put  forth,  they  have  proved  to  be  in  harmony,  on  all  essential  points, 
with  those  of  so  philosophic  and  penetrating  a  thinker. — Of  modern  Neurologists,  the  fore- 
most rank  is  justly  to  be  assigned  to  Sir  C.  Bell,  for  his  discovery  of  the  anatomical  distinct- 
ness of  the  sensory  and  motor  nerves,  and  for  the  inferences  to  which  this  discovery  led. 
And  the  author  is  quite  of  opinion  that  the  rediscovery  of  the  Reflex  Function  of  the  Spinal 
Cord  by  Dr.  M.  Hall  (which  he  believes  to  have  been  entirely  original  on  that  gentleman's 
part)  has  constituted  an  era  of  no  less  importance ;  although  his  limitation  of  the  doctrine  of 
reflex  action  to  the  Spinal  ganglia  has  subsequently  tended,  in  the  Author's  opinion,  rather 
to  retard  than  to  promote  the  progress  of  Neurology.  In  extending  this  view  to  the  Sen- 
sory Ganglia,  and  in  showing  that  they  minister  to  a  class  of  "  reflex"  actions  peculiarly 
their  own,  the  Author  believes  that  he  may  claim  to  have  made  the  first  definite  attempt  to 
free  it  from  this  limitation  ;  and  for  its  further  extension  to  the  Cerebrum,  Science  is  in- 
debted to  Dr.  Laycock,  to  whose  Essay  on  the  Reflex  Action  of  the  Brain,  the  Author  has 
already  expressed  his  obligations.  To  these  he  would  add  the  names  of  Dr.  Holland  and 
Dr.  Todd,  as  those  of  writers  from  whom  he  has  derived  many  valuable  suggestions,  which 
have  not,  he  trusts,  been  without  fruit  in  his  own  mind. — It  is  a  circumstance  not  devoid  of 


'  "  Gulstonian  Lectures  on  the  Nervous  System,"  in  "Medical  Times,"  1849,  No.  495. 


848      OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 

interest,  that,  during  the  present  century,  notwithstanding  the  large  amount  of  anatomical 
and  experimental  inquiry  which  has  been  directed  to  the  Nervous  System  both  in  France 
and  Germany,  and  the  vast  addition  to  our  knowledge  of  details  which  has  hence  arisen, 
the  great  advances  in  the  general  doctrines  of  this  department  of  the  science  should  have 
been  made  by  British  Physiologists.] 


CHAPTER  XV. 

OF    SENSATIONS,   AND    THE    ORGANS    OF    THE    SENSES. 

1. —  Of  Sensation  in  General. 

850.  BY  the  term  Sensation  is  rightly  understood  that  change  in  the  condition 
of  the  Mind  by  which  we  become  aware  of  an  impression  made  upon  some  part 
of  the  Body;  or,  in  a  briefer  form  of  expression,  it  may  be  denned  to  be  the 
consciousness  of  an  impression.  Some  Physiologists  have,  it  is  true,  spoken  of 
a  sensation  without  consciousness;  but  it  seems  very  desirable  to  limit  the  term 
to  the  mental  change ;  since  the  word  impression  serves  to  designate  the  change 
produced  in  the  afferent  nerves  by  an  external  cause,  up  to  the  point  at  which 
the  mind  becomes  conscious  of  it.  We  have  seen  reason  to  believe  that  the 
impressions  communicated  to  the  Spinal  Cord  may  there  excite  motor  actions, 
without  occasioning  true  sensation  ;  and  it  would  seem  to  be  with  a  certain  part 
of  the  Encephalon  only,  that  the  Mind  possesses  the  relation  necessary  for  the 
production  of  such  a  change  in  it.  Hence  this  organ  is  spoken  of  as  the  Sen- 
sorium.  For  the  reasons  already  given  (§§  732-4),  it  seems  probable  that  the 
ganglia  of  Special  Sensation  are  the  essential  instruments  of  this  function,  rather 
than  the  Cerebral  Hemispheres.  The  afferent  nervous  fibres,  which  connect  the 
various  parts  of  the  body  with  the  Sensorium,  are  termed  sensory ;  and  these 
are  distributed  in  very  different  proportions  to  different  parts.  Those  parts  of 
the  body  which  are  endowed  with  sensory  fibres,  and  impressions  on  which,  there- 
fore, give  rise  to  sensation,  are  ordinarily  spoken  of  as  sensible  ;  and  different 
parts  are  spoken  of  as  sensible  in  different  degrees,  according  to  the  strength 
of  the  sensation  which  is  produced  by  a  corresponding  impression  on  each.  In 
accordance  with  what  was  formerly  stated  (§  355)  of  the  dependence  of  all 
Nervous  action  on  the  continuance  of  the  Circulation  of  blood,  it  is  found  that 
the  sensory  nerves  are  distributed  pretty  much  in  the  same  proportion  as  the 
bloodvessels ;  that  is  to  say,  in  the  non-vascular  tissues — such  as  the  epider- 
mis, hair,  nails,  cartilage,  and  bony  substance  of  the  teeth — no  nerves  exist, 
and  there  is  an  entire  absence  of  sensibility;  and  in  those  whose  vascular- 
ity  is  trifling,  the  sensibility  is  dull,  as  is  the  case  with  bones,  tendons, 
ligaments,  fibrous  membranes,  and  other  parts  whose  functions  are  simply  me- 
chanical, and  even  with  serous  and  areolar  membranes.  Many  of  these  tex- 
tures are  acutely  sensible,  however,  under  certain  circumstances ;  thus,  although 
tendons  and  ligaments  may  be  wounded,  burned,  &c.,  without  giving  rise  to 
much  consciousness  of  the  injury,  they  cannot  be  stretched  without  the  pro- 
duction of  considerable  pain ;  and  the  fibrous,  serous,  and  areolar  tissues,  when 
their  vascularity  is  increased  by  inflammation,  also  become  extremely  susceptible 
of  painful  impressions.  All  very  vascular  parts,  however,  do  not  possess  acute 
sensibility ;  the  muscles,  for  instance,  are  furnished  with  a  large  supply  of  blood, 
to  enable  them  to  perform  their  peculiar  function ;  but  they  are  not  sensible  in 
by  any  means  the  same  proportion.  Even  the  substance  of  the  brain,  and  of 
the  nerves  of  special  sensation,  appears  to  be  destitute  of  this  endowment ;  and 
the  same  may  be  said  of  the  mucous  membranes  lining  the  interior  of  the 


OP  SENSATION  IN  GENERAL.  849 

several  viscera,  which,  in  the  ordinary  condition,  are  much  less  sensible  than 
the  membranes  that  cover  those  viscera,  although  so  plentifully  supplied 
with  blood  for  their  especial  purposes.  The  most  sensible  of  all  parts  of 
the  body  is  the  Skin,  in  which  the  sensory  nerves  spread  themselves  out  into  a 
minute  network  ;  and  even  of  this  tissue,  the  sensibility  differs  greatly  in  dif- 
ferent parts.  The  organs  of  special  sensation  become,  by  the  peculiar  charac- 
ter of  the  nerves  with  which  they  are  supplied,  the  recipients  of  impressions 
of  a  particular  kind  :  thus  the  eye  is  sensible  to  light,  the  ear  to  sound,  &c. ; 
and  whatever  amount  of  ordinary  sensibility  they  possess,  is  dependent  upon 
other  sensory  nerves.  The  eye,  for  example,  contrary  to  the  usual  notions,  is  a 
very  insensible  part  of  the  body,  unless  affected  with  inflammation  ;  for,  though 
the  mucous  membrane  which  covers  its  surface,  and  which  is  prolonged  from 
the  skin,  is  acutely  sensible  to  tactile  impressions,  the  interior  is  by  no  means 
so,  as  is  well  known  to  those  who  have  operated  much  on  this  organ.  And  there 
are  many  parts  of  the  body  that  are  supplied  with  the  common  sensory  nerves, 
which  receive  and  convey  to  the  mind  impressions  of  particular  kinds,  with 
much  greater  readiness  than  they  communicate  those  of  a  different  description. 

851.  An  active  Capillary  Circulation  being  essential  to  the  Sensibility  of 
every  part  supplied  with  nerves,  any  cause  which  retards  this  deadens  the  sen- 
sibility, as  is  well  seen  with  regard  to  Cold  ;  and,  on  the  other  hand,  an  increase 
in  its  energy  produces  a  corresponding  increase  in  the  sensibility,  as  is  peculiarly 
evident  in  the  "  active  congestion"  which  usually  precedes  and  accompanies  In- 
flammation.    A  diminution  or  increase  of  sensibility  to  external  impressions  may 
arise,  however,  not  only  from  an  abnormal  state  of  the  circulation  in  the  organ  or 
part  itself,  but  from  the  similar  conditions  affecting  that  part  of  the  sensorium  in 
which  the  impressions  are  received.     Thus,  in  those  various  conditions  of  the 
Encephalon,  in  which  either  a  stagnation  of  the  circulation,  or  an  abnormal  state 
of  the  blood,  occasions  a  diminished  functional  activity  in  the  Sensorial  centres, 
this  is  marked  by  obtuseness  to  sensory  impressions  j  on  the  other  hand,  in 
active  congestion  of  the  brain,  the  most  ordinary  external  impressions  produce 
sensations  of  an  unbearable  violence ;  and  there  are  some  peculiar  conditions 
of  the  nervous  system,  known  under  the  name  of  hysterical,  in  which   the 
patients  manifest  the  same  discomfort,  even  when  the  circulation  is  in  a  feeble 
rather  than  in  an  excited  state.1     It  is  remarkable  that  the  sensibility  of  the  mu- 
cous membranes  lining  the  internal  organs  is  less  exalted  by  the  state  of  inflamma- 
tion, than  is  that  of  most  other  parts ;  and  in  this  arrangement  we  may  trace 
a  wise  and  beneficent  provision ;  since,  were  it  otherwise,  the  functions  neces- 
sary to  life  could  not  be  performed  without  extreme  distress,  with  a  very  mode- 
rate amount  of  disorder  in  the  viscera.     If  a  joint  is  inflamed,  we  can  give  it 
rest ;  but  to  the  actions  of  the  alimentary  canal  we  can  give  little  voluntary 
respite. 

852.  The  feelings  of  Pain  or  Pleasure  which  are  connected  with  particular 
sensations,  cannot  (for  the  most  part  at  least)  be  explained  upon  any  other  prin- 
ciple than  that  of  the  necessary  association  of  these  feelings,  by  an  original  law 
of  our  nature,  with  the  sensations  in  question.     As  a  general  rule,  it  may  be 
stated  that  the  violent  excitement  of  any  sensation  is  disagreeable,  even  when 
the  same  sensation  in  a  moderate  degree  may  be  a  source  of  extreme  pleasure. 
This  is  the  case  alike  with  those  impressions  which  are  communicated  through 
the  organs  of  sight,  hearing,  smell,  and  taste,  as  with  those  that  are  received 
through  the  nerves  of  common  sensation;  and  there  can  be  no  doubt  that  the 
final  cause,  or  purpose,  of  the  association  of  painful  feelings  with  such  violent 

1  The  influence  of  toxic  agents  introduced  into  the  blood,  in  producing  Anaesthesia  and 
Hypersesthesia,  constitutes  a  very  wide  field  of  inquiry,  which  is  well  deserving  of  careful 
cultivation.     It  is  remarkable  that  Lead  should  be  capable  of  inducing  either  of  these  states. 
54 


850     OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 

excitement,  is  to  stimulate  the  individual  to  remove  himself  from  what  would 
be  injurious  in  its  effects  upon  the  system.  Thus,  the  pain  resulting  from  vio- 
lent pressure  on  the  cutaneous  surface,  or  from  the  proximity  of  a  heated  body, 
gives  warning  of  the  danger  of  injury,  and  excites  mental  operations  destined  to 
remove  the  part  from  the  influence  of  the  injurious  cause  :  and  this  is  shown  by 
the  fact  that  loss  of  sensibility  is  frequently  the  indirect  occasion  of  severe 
lesions — the  individual  not  receiving  the  customary  intimation  that  an  injurious 
process  is  taking  place.1  Instances  have  occurred,  in  which  severe  inflammation 
of  the  membrane  lining  the  passages  has  resulted  from  the  effects  of  ammoniacal 
vapors,  introduced  into  them  during  a  state  of  syncope — the  patient  not  receiving 
that  notice  of  the  irritation  which,  in  an  active  condition  of  his  nervous  system, 
would  have  prevented  him  from  inhaling  the  noxious  agent. 

853.  It  is  a  general  rule,  with  regard  to  all  sensations,  that  their  intensity  is 
much  affected  by  Habit;  being  greatly  diminished  by  frequent  and  continual 
repetition.  This  is  not  the  case,  however,  with  regard  to  those  sensations  to 
which  the  attention  is  peculiarly  directed;  for  these  lose  none  of  their  acuteness  by 
frequent  repetition;  on  the  contrary,  they  become  much  more  readily  cognizable 
by  the  mind.  We  have  a  good  example  of  both  facts  in  the  effects  of  sounds 
upon  sleeping  persons  (§  843).  The  general  law,  then,  seems  to  be,  that  Sen- 
sations, not  attended  to,  are  blunted  by  frequent  repetition ;  and  this  may  per- 
haps be  connected  with  certain  other  general  facts,  which  lie  under  the  obser- 
vation of  every  one. — It  is  well  known  that  th£  vividness  of  sensations  depends 
rather  on  the  degree  of  change  which  they  produce  in  the  system,  than  on  the 
absolute  amount  of  the  impressing  force  ;  and  this  is  alike  the  case  with  regard 
to  the  special  and  the  ordinary  sensations.  Thus,  our  sensations  of  heat  and 
cold  are  entirely  governed  by  the  previous  condition  of  the  parts  affected ;  as  is 
shown  by  the  well-known  experiment  of  putting  one  hand  into  hot  water,  the 
other  into  cold,  and  then  transferring  both  to  tepid  water,  which  will  seem  cool  to 
one  hand,  and  warm  to  the  other.  Every  one  knows,  too,  how  much  more  we 
are  affected  by  a  warm  day  at  the  commencement  of  summer,  than  by  an 
equally  hot  day  later  in  the  season.  The  same  is  the  case  in  regard  to  light 
and  sound,  smell  and  taste.  A  person  going  out  of  a  totally  dark  room  into 
one  moderately  bright,  is  for  the  time  painfully  impressed  by  the  light,  but  soon 
becomes  habituated  to  it ;  whilst  another,  who  enters  it  from  a  room  brilliantly 
illuminated,  will  consider  it  dark  and  gloomy.  Those  who  are  constantly  ex- 
posed to  very  loud  noises  become  almost  unconscious  of  them,  and  are  even 
undisturbed  by  them  in  illness ;  and  the  medical  student  well  knows  that  even 

1  The  following  case,  recorded  in  the  "Journal  of  a  Naturalist,"  affords  a  remarkable 
instance  of  this  general  fact.  The  correctness  of  the  statement  having  been  called  in  ques- 
tion, it  was  fully  confirmed  by  Mr.  Richard  Smith,  the  late  senior  surgeon  of  the  Bristol 
Infirmary,  under  whose  care  the  sufferer  had  been.  "  A  travelling  man,  one  winter's  even- 
ing, laid  himself  down  upon  the  platform  of  a  lime-kiln,  placing  his  feet,  probably  numbed 
with  cold,  upon  the  heap  of  stones,  newly  put  on  to  burn  through  the  night.  Sleep  over- 
came him  in  this  situation ;  the  fire  gradually  rising  and  increasing,  until  it  ignited  the  stones 
upon  which  his  feet  were  placed.  Lulled  by  the  warmth,  the  man  slept  on ;  the  fire  in- 
creased until  it  burned  one  foot  (which  probably  was  extended  over  a  vent-hole)  and  part 
of  the  leg  above  the  ankle  entirely  off,  consuming  that  part  so  effectually,  that  a  cinder- 
like  fragment  was  alone  remaining — and  still  the  wretch  slept  on !  and  in  this  state  was 
found  by  the  kiln-man  in  the  morning.  Insensible  to  any  pain,  and  ignorant  of  his  mis- 
fortune, he  attempted  to  rise  and  pursue  his  journey,  but  missing  his  shoe,  requested  to 
have  it  found ;  and  when  he  was  raised,  putting  his  burnt  limb  to  the  ground  to  support 
his  body,  the  extremity  of  his  leg-bone,  the  tibia,  crumbled  into  fragments,  having  been 
calcined  into  lime.  Still  he  expressed  no  sense  of  pain,  and  probably  experienced  none ; 
from  the  gradual  operation  of  the  fire,  and  his  own  torpidity  during  the  hours  his 
foot  was  consuming.  This  poor  drover  survived  his  misfortunes  in  the  hospital  about  a 
fortnight;  but  the  fire  having  extended  to  other  parts  of  his  body,  recovery  was  hopeless." 
—See  also  \  349,  note. 


OF  SENSATION  IN  GENERAL.  851 

the  effluvia  of  the  dissecting-room  are  not  perceived  when  the  organ  of  smell  is 
habituated  to  them ;  although  an  intermission  of  sufficient  length  would,  in  either 
instance,  occasion  a  renewal  of  the  first  unpleasant  feelings,  when  the  individual 
is  again  subjected  to  the  impression. — Again,  it  is  a  well-known  fact  that  im- 
pressions made  upon  the  organs  of  sense  continue  to  affect  the  consciousness 
for  a  time  after  the  cause  of  the  impression  has  ceased  :  it  is  in  this  man- 
ner that  a  musical  tone,  which  seems  perfectly  continuous,  results  from  a  series 
of  consecutive  vibrations,  following  each  other  with  a  certain  rapidity;  and  that 
a  line  or  circle  of  light  is  produced  by  a  luminous  body  moving  with  a  certain 
velocity.  And  there  seems  reason  to  believe  that  sensorial  changes  of  frequent 
recurrence  produce  a  modification  in  the  nutrition  of  the  Sensorium  itself,  which 
grows  to  them,  as  it  were,  just  as  the  Cerebrum  may  be  considered  as  growing 
to  the  mode  in  which  it  is  habitually  exercised  (§  807);  for  not  only  would  the 
production  of  such  a  modification  be  quite  in  accordance  with  the  general  phe- 
nomena of  Nutrition,1  but  we  can  scarcely  otherwise  explain  the  progressive  form- 
ation of  that  connection  between  sensorial  changes  and  motor  actions  which 
gives  rise  to  the  "secondarily  automatic"  movements  (§  749). — Hence  it  seems 
reasonable  to  attribute  that  diminution  in  the  force  of  Sensations  which  is  the 
consequence  of  their  habitual  recurrence,  to  the  want  of  such  a  change  in  the 
condition  of  the  Sensorium  as  is  needful  to  produce  an  impression  on  the  con- 
sciousness ;  the  effects  which  they  at  first  induced  being  no  longer  experienced  m 
the  same  degree,  when  the  structure  of  the  part  has  accommodated  itself  to 
them. 

854.  It  is  curious,  also,  that  the  feelings  of  Pain  or  Pleasure,  which  unac- 
customed sensations  excite,  are  often  exchanged  for  each  other,  when  the  system 
is  habituated  to  them ;  this  is  especially  the  case,  in  regard  to  impressions  com- 
municated through  the  organs  of  Smell  and  Taste.     There  are  many  articles  in 
common  use  among  mankind — such  as  tobacco,  fermented  liquors,  &c.,  the  use 
of  which  cannot  be  said  to  produce  a  natural  enjoyment,  since  they  are  at  first 
unpleasant  to  most  persons;  and  yet  they  first  become  tolerable,  then  agreeable, 
and  at  last  the  want  of  them  is  felt  as  a  painful  privation,  and  the  stimulus  must 
be  applied  in  an  increasing  degree,  in  order  to  produce  the  usual  effect . 

855.  It  is  through  the  medium  of  Sensation,  that  we  acquire  a  knowledge  of 
the  material  world  around  us,  by  the  psychical  operations  which  its  changes 
excite  in  ourselves.     The  various  kinds  or  modes  of  Sensation  excite  in  us 
various  ideas  regarding  the  properties  of  matter;  and  these  properties  are  known 
to  us  only  through  the  changes  which  they  produce  in  the  several  organs  (§786). 
It  is  well  known  that  instances  exist,  in  which,  from  some  imperfection  of  the 
organization,  there  is  an  incapacity  for  distinguishing  colors  or  musical  tones, 
whilst  there  is  no  want  of  sensibility  to  light  or  sound ;  and  that  some  persons 
are  naturally  endowed  with  a  much  greater  range  of  the  sensory  faculties  than 
others  possess.     Hence  it  does  not  seem  at  all  improbable  that,  there  are  pro- 
perties of  matter,  of  which  none  of  our  senses  can  take  immediate  cognizance ; 
and  which  other  beings  might  be  formed  to  perceive,  in  the  same  manner  as  we 
are  sensible  to  light,  sound,  &c.     Thus  many  animals  are  affected  by  atmo- 
spheric changes  in  such  a  manner  that  their  actions  are  regarded  by  Man  as 
indications  of  the  probable  state  of  the  weather ;  and  the  same  is  the  case  in  a 
less  degree  with  some  of  our  own  species,  who  are  peculiarly  susceptible  of  the 
same  influences. — Now  the  most  universal  of  all  the  qualities  or  properties  of 

'  We  have  a  remarkable  exemplification  of  this  in  the  tolerance  which  may  be  gradually 
established  in  the  system  for  various  toxic  agents,  especially  for  such  as  particularly  affect 
the  Nervous  substance,  such  as  Opium  or  Alcohol.  It  seems  impossible  to  explain  this 
tolerance  on  any  other  hypothesis  than  that  of  the  alteration  of  the  nutrition  of  the 
tissue  by  repeated  doses,  so  that  no  further  change  can  be  produced  by  the  quantity  ori- 
ginally taken. 


852      OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 

Matter,  on  which,  in  fact,  our  notion  of  it  is  chiefly  founded  (§  804),  is  its 
occupation  of  space,  producing  a  more  or  less  complete  resistance  to  displacement; 
and  this  quality  is  that  through  which  alone  any  knowledge  of  the  external 
world  can  be  obtained  by  a  large  proportion  of  the  lower  Animals ;  contact 
between  their  own  surface  and  some  material  body  being  required  to  produce 
sensation.  We  shall  presently  see,  however,  that  the  idea  of  the  shape  of  a 
body  which  we  form  from  the  touch;  results  from  a  very  complex  process,  such 
as  animals  of  the  lower  grades  can  scarcely  be  supposed  to  exercise.  There  can 
be  little  doubt  that,  next  to  the  mere  sense  of  resistance,  sensibility  to  tempera- 
ture is*  the  most  universally  diffused  through  the  Animal  kingdom ;  and  probably 
the  consciousness  of  luminosity  is  the  next  in  the  extent  of  its  diffusion.1  It  is 
probable  that  the  sense  of  taste  (which  has  a  close  affinity  to  that  of  touch)  exists 
very  low  down  in  the  animal  scale,  being  obviously  of  great  importance  in  the 
selection  of  food ;  but  the  Anatomist  has  no  means  of  ascertaining  where  this 
refinement  exists,  and  where  it  does  not ;  since  the  organs  of  taste  and  touch 
are  very  similar.  The  sense  of  hearing  does  not  seem  to  be  distinctly  present 
among  the  Invertebrate  animals,  except  in  such  as  approach  most  nearly  to  the 
Vertebrata ;  it  is  not  improbable,  however,  that  sonorous  vibrations  may  pro- 
duce an  effect  upon  the  system  of  those  animals,  which  do  not  receive  them  as  sound. 
The  sense  of  smell,  which  is  concerned  with  one  of  the  least  general  properties 
of  matter,  appears  to  be  the  least  widely  diffused  among  the  whole  ;  being  only 
possessed  in  any  high  degree  by  Vertebrated  animals,  and  being  but  feebly  pre- 
sent in  a  large  proportion  of  these. 

856.  Besides  the  various  kinds  of  sensibility  which  have  been  just  enume- 
rated, there  are  others  which  are  ordinarily  associated  together,  along  with  the 
sense  of  material  resistance  (and  its  several  modifications),  and  the  sense  of 
temperature,  under  the  head  of  Common  Sensation ;  but  several  of  them,  espe- 
cially those  which  originate  in  the  body  itself,  can  scarcely  be  regarded  in  this 
light.  Such  are  the  feelings  of  hunger  and  thirst ;  that  of  nausea ;  that  of 
distress  resulting  from  suspended  aeration  of  the  blood;  that  of  " sinking  at  the 
stomach,"  as  it  is  vulgarly  but  expressively  described,  which  results  from  strong 
mental  emotion ;  the  sexual  sense,  and  perhaps  some  others. — Now  in  regard  to 
all  these,  it  is  impossible  in  the  present  state  of  our  knowledge  to  say,  whether 
their  peculiarity  results  from  the  particular  constitution  of  the  nerves  that 
receive  and  convey  them,  or  only  from  a  modification  in  the  impressing  causes, 
from  the  particular  endowments  of  their  ganglionic  centres,  and  from  the  mode 
in  which  they  operate.  Thus  we  have  no  evidence  whether  the  nervous  fibrils, 
which  convey  from  the  lungs  the  sense  of  distress  resulting  from  deficient  aera- 
tion, are  of  the  same  or  of  a  different  character  from  those  which  convey  from 
the  surface  of  the  air-passages  the  sense  of  the  contact  of  a  foreign  body.  But 
as  we  know  that  all  the  trunks,  along  which  these  peculiar  impressions  travel, 
do  minister  to  ordinary  sensation,  whilst  the  nerves  of  truly  special  sensation 
are  not  sensible  to  common  impressions,  it  is  evident  that  the  probability  seems 
in  favor  of  the  identity  of  the  fibres,  which  minister  to  these  sensations,  with 
those  of  the  usual  sensory  character.  We  shall  see  that,  with  regard  to  the 
sense  of  Temperature,  there  is  strong  evidence  that  its  peculiarity  depends  on 
the  speciality  of  the  apparatus  by  which  impressions  are  received  at  the  peri- 

1  There  is  good  reason  to  believe,  from  observation  of  their  habits,  that  many  animals 
are  susceptible  of  the  influence,  and  are  directed  by  the  guidance  of  light ;  whilst  their 
organs  are  not  adapted  to  receive  true  visual  impressions,  or  to  form  optical  images :  and 
such  would  seem  to  be  the  function  of  the  red  spots  frequently  seen  on  prominent  parts 
of  the  lower  Articulata  and  Mollusca,  and  even  of  some  lladiata.  Wherever  these  are  of 
sufficient  size  to  allow  their  structure  to  be  examined,  they  are  found  to  be  largely  sup- 
plied with  nerves,  but  to  be  destitute  of  the  peculiar  organization  which  alone  constitutes 
a  true  eye. 


Or   SENSATION   IN    GENERAL.  853 

pheral  extremities  of  the  tactile  nerves,  rather  than  upon  any  peculiarity  in  the 
transmitting  fibres  (§  866). 

857.  There  are  certain  external  causes  which  can  excite  changes  in  the 
Sensorium  through  several  different  channels;  the  sensation  being  in  each  case 
characteristic  of  the  particular  nerve  on  which  the  impression  is  m'ade.     Thus 
pressure,  which  produces  through  the  nerves  of  common  sensation  the  feeling  of 
resistance,  is   well  known  to  occasion,  when  exerted  on  the  eye,  the  sensa- 
tion of  light  and  colors ;  and,  when  made  with  some  violence  on  the  ear,  to  pro- 
duce tinnitus  aurium.     It  is  not  so  easy  to  excite  sensations  of  taste  and  smell, 
by  mechanical  irritation  ;  and  yet,  as  Dr.  Baly1  has  shown,  this  may  readily  be 
accomplished  in  regard  to  the  former.     The  sense  of  nausea  may  be  easily  pro- 
duced, as  is  familiarly  known,  by  mechanical  irritation  of  the  fauces.    Electricity 
still  more  completely  possesses  the  power  of  affecting  all  the  sensory  nerves  with 
the  changes  which  are  peculiar  to  them ;  for,  by  proper  management,  an  indi- 
vidual may  be  made  conscious  at  the  same  time  of  flashes  of  light,  of  distinct 
sounds,  of  a  phosphoric  odor,  of  a  peculiar  taste,  and  of  pricking  sensations,  all 
excited  by  the  same  cause,  the  effects  of  which  are  modified  by  the  respective 
peculiarities  of  the  instruments  through  which  it  operates. — But  although  there 
are  some  stimuli  which  can  produce  sensory  impressions  on  all  the  nerves  of 
sensation,  it  will  be  found  that  those  to  which  any  one  organ  is  peculiarly  fitted 
to  respond,  produce  little  or  no  effect  upon  the  rest.     Thus  the  ear  cannot  dis- 
tinguish the  slightest  difference  between  a  luminous  and  a  dark  object.     A 
tuning-fork,  which,  when  laid  upon  the  ear  whilst  vibrating,  produces  a  distinct 
musical  tone,  excites  no  other  sensation,  when  placed  upon  the  eye,  than  a 
slight  jarring  feeling.     The  most  delicate  touch  cannot  distinguish  a  substance 
which  is  sweet  to  the  taste,  from  one  which  is  bitter ;  nor  can  the  taste  (if  the 
communication  between  the  mouth  and  the  nose  be  cut  off)  perceive  anything 
peculiar  in  the  most  strongly-odoriferous  bodies. — It  may  hence  be  inferred  that 
no  nerve  of  special  sensation  can,  by  any  possibility,  take  on  the  function  of 
another. 

858.  But  whilst  there  is  evidence  of  the  peculiar  aptitudes  of  the  different 
Sensory  nerves,  to  receive  and  convey  impressions  of  particular  kinds,  yet  there 
can  be  no  doubt  that  their  special  endowments  are  in  great  degree  dependent 
upon  those  of  the  central  organs  in  which  they  terminate.     For  with  regard  to 
all  kinds  of  Sensation,  it  is  to  be  remembered  that  the  change  of  which  the 
Mind  is  informed  is  not  the  change  at  the  peripheral  extremities  of  the  nerves, 
but  the  change  communicated  to  the  Sensorium ;  hence  it  results  that  external 
agencies  can  give  rise  to  no  kind  of  sensation  which  cannot  also  be  produced 
by  internal  causes,  exciting  changes  in  the  condition  of  the  nerves  in  their 
course.     This  very  frequently  happens  in  regard  to  the  senses  of  sight  and 
hearing;  flashes  of  light  being  seen,  and  ringing  sounds  in  the  ears  being  heard, 
when  no  external  stimulus  has  produced  such  impressions.     The  production  of 
odorous  and  gustative  sensations  from  internal  causes  is  perhaps  less  common ; 
but  the  sense  of  nausea  is  more  frequently  excited  in  this  manner,  than  by  the 
direct  contact  of  the  nauseating  substance  with  the   tongue  or  fauces.     The 
various  phases  of  common  sensibility  often  originate  thus;  and  the  sense  of 
temperature  is  frequently  affected  without  any  corresponding  affection  of  the 
tactile  sensations,  a  person  being  sensible  of  heat  or  of  chilliness  in  some  part 
of  his  body,  without  any  real  alteration  of  its  temperature.     The  most  common 
of  the  internal  causes  of  these  subjective  sensations  (as  they  have  been  termed, 
in  contradistinction  to  the  objective,  which  result  from  a  real  material  object) 
is  congestion  or  inflammation ;  and  it  is  interesting  to  remark  that  this  cause, 
operating  through  each  nerve,  produces  in  the  sensorium  the  changes  to  which 

1  Translation  of  Muller's  "Elements  of  Physiology,"  p.  1062,  note. 


854      Or  SENSATION,  AND  THE  ORGANS  OP  THE  SENSES. 

that  nerve  is  usually  subservient.     Thus,  congestion  in  the  nerves  of  common 
sensation  gives  rise  to  feelings  of  pain  or  uneasiness;  but  when  occurring  in  the 
retina  and  optic  nerve  it  produces  flashes  of  light ;  and  in  the  auditory  nerve  it 
occasions  "a  noise  in  the  ears." — But  further,  the  phenomena  of  subjective  sen- 
sation often  originate  in  peculiar  conditions  of  the  Encephalon  itself,  and  not 
in  the  organs  of  sense  or  the  nervous   trunks;  thus,  in  dreaming,  we  have 
frequently  very  vivid  pictures  of  external  objects  presented  to  our  minds;  and 
we  sometimes  distinctly  hear  voices  and  musical  tones,  or  have  perceptions 
(though  this  is  less  common)  of  tastes  and  odors.     The  phenomena  of  spectral 
illusions  are  very  nearly  connected  with  those  of  dreaming;  both  may  be  in 
some  degree  influenced  by  external  causes,  acting  upon  the  organs  of  sensation, 
which  are  misinterpreted  (as  it  were)  by  the  mind,  owing  to  its  state  of  imper- 
fect operation;  but  both  also  may  entirely  originate  in  the  central  organs. 
There  seems  to  be  no  difference,  in  the  feelings  of  the  individual,  between  the 
sensations  thus  originating,  and  those  which  are  produced  in  the  usual  manner; 
for  we  find  that,  unless  otherwise  convinced  by  their  own  reason,  persons  who 
witness  spectral  illusions  believe  as  firmly  in  the  reality  of  the  objects  that  come 
before  their  minds,  as  if  the  images  of  those  objects  were  actually  formed  on 
their  retinae.     This  is  another  proof,  if  any  were  wanting,  that  the  organ  of 
sense,  and  the  nerve  belonging  to  it,  are  but  the  instruments  by  which  certain 
changes  are  produced  in  the  Sensorium;  by  which  changes,  and  not  by  the 
immediate  impressions  of  the  objects,   our  Consciousness  is  really  affected. 
There  is  yet  another  mode,  however,  in  which  subjective  sensations  may  be  ex- 
cited; namely,  by  sensations  originating  in  objective  impressions  on  other  parts. 
Thus  the  irritation  of  a  calculus  in  the  bladder  gives  rise  to  pain  at  the  end  of 
the  penis;  disease  of  the  hip-joint  is  often  first  indicated  by  pain  in  the  knee; 
irritation  of  the  ovary  will  cause  pain  under  the  mamma ;  various  disorders  of 
the  liver  occasion  pain  under  the  left  scapula;  attention  is  often  drawn  to 
diseases  of  the  heart  by  shooting  pains  along  the  arms;  stimulation  of  the  nip- 
ple, whether  in  the  male  or  female,  gives  rise  to  peculiar  sensations  referred  to 
the  genital  organs;  the  sudden  introduction  of  ice  into  the  stomach  will  cause 
intense  pain  in  the  supraorbital  region,  and  the  same  pain  is  frequently  occa- 
sioned by  the  presence  of  acid  in  the  stomach,  and  may  be  very  quickly  relieved 
by  its  neutralization  with  an  alkali.     It  will  be  seen  that  in  most  of  these  cases 
it  is  impossible  to  refer  the  sensations  to  any  direct  nervous  connection  with  the 
parts  on  which  the  impressions  are  made;  and  they  can  scarcely  be  otherwise 
accounted  for   than  by  supposing   that   these  impressions  produce   sensorial 
changes,  which  are  referred  to  other  parts,  in  virtue  of  some  central  track  of 
communication  with  them,  analogous  to  that  through  which  reflex  movements 
are  excited.     There  are  circumstances,  indeed,  which  seem  to  render  it  not 
improbable  that,  just  as  the  impression  brought  by  the  afferent  nerves  to  the 
central  organs,  excites  a  reflex  movement  by  disturbing  the  polarity  of  a  motor 
nerve,  it  may  excite  a  "reflex  sensation"  by  disturbing  the  polarity  of  a  sensory 
•nerve.     Certain  it  is  that,  after  the  long  continuance  of  some  of  these  reflex 
sensations,  the  organs  to  which  they  are  referred  themselves  become  diseased, 
although  previously  quite  healthy;  thus,  pain  in  the  testicle  is  frequently  in- 
duced by  irritation  having  its  seat  in  the  lower  part  of  the  spine,  but,  if  this 
continue,  some  morbid  affection  of  the  testicle  itself  is  likely  to  supervene ;  and 
Sir  B.  Brodie1  has  recorded  several  cases,  in  which  " nervous"  pains  in  various 
parts,  apparently  of  a  purely  subjective  character,  have  been  followed  by  pain 
and  swelling  of  the  integuments.     These  phenomena  are  perhaps  due  to  that 
habitual  direction  of  the  consciousness  to  the  part  which  is  prompted  by  the 
habitual  sensation;  this  condition,  as  we  shall  see  hereafter  (CHAP,  xvin.), 

1  "On  Local  Nervous  Affections,"  1837. 


OF    SENSATION   IN   GENERAL.  855 

being  itself  adequate  to   the  production  of  changes  in  its  ordinary  nutritive 
action. 

859.  It  seems  to  be  by  an  innate  law  of  our  constitution,  that  these  subject- 
ive sensations,  whether  originating  at  the  central  terminations  of  nerves,  or  in 
the  course  of  their  trunks,  should  be  referred  by  the  mind  to  the  ordinary  situa- 
tions of  their  peripheral  terminations;  even  though  these  should  not  exist,  or 
should  be  destitute  of  the  power  of  receiving  impressions.     Thus  after  amputa- 
tions, the  patients  are   for  some   time   affected  with   sensations  (originating 
probably  in  the  cut  extremities  of  the  nerves),  which  they  refer  to  the  removed 
extremities ;  the  same  has  been  noticed  in  regard  to  the  eye,  as  well  when  it 
has  been  completely  extirpated,  as  when  its  powers  have  been  destroyed  by 
disease.     The  effects  of  the  Taliacotian  operation  also  exhibit  the  operation  of 
this  law  in  a  curious  manner }  for  until  the  flap  of  skin  from  which  the  new 
nose  is  formed  obtains  vascular  and  nervous  connections  in  its  new  situation, 
the  sensation  produced  by  touching  it  is  referred  to  the  forehead.     Another 
interesting  illustration  of  it  may  be  obtained  by  the  following  very  simple  ex- 
periment :  If  the  middle  finger  of  either  hand  be  crossed  behind  the  forefinger, 
so  that  its  extremity  is  on  the  radial  side  of  the  latter,  and  the  ends  of  the  two 
fingers  thus  disposed  be  rolled  over  a  marble,  pea,  or  other  round  body,  a  sen- 
sation will  be  produced,  which,  if  uncorrected  by  reason,  would  cause  the  mind 
to  believe  in  the  existence  of  two  distinct  bodies;  this  is  due  to  the  impression 
being  made  at  the  same  time  upon  the  radial  side  of  the  forefinger,  and  the 
ulnar  side  of  the  middle  finger — two  joints  which,  in  the  natural  position,  are  at 
a  considerable  distance. 

860.  Sensations  of  a  purely  subjective  nature  may  excite  precisely  the  same 
muscular  movements,  or  other  changes  in  the  bodily  system,  as  do  similar 
sensations  produced  by  objective  realities.     Of  this  we  have  abundant  evidence 
in  the  effects  of  sensations  called  up  by  ideas   (§§  758,  863) ;  the  following 
example,  however,  is  peculiarly  valuable,  a,s  showing  that  the  sensation  still 
operates  in  directing  movement,  even  though  there  be  an  intellectual  conscious- 
ness that  there  is  no  objective  cause  for  it,  and  that  the  movement  is  conse- 
quently inappropriate.     A  lady  nearly  connected  with  the  Author,  having  been 
frightened  in  childhood  by  a  black  cat,  which  sprang  up  from  beneath  her  pillow 
just  as  she  was  laying  her  head  upon  it,  was  accustomed  for  many  years  after- 
wards, whenever  she  was  at  all  indisposed,  to  see  a  black  cat  on  the  ground 
before  her ;  and  although  perfectly  aware  of  the  spectral  character  of  the  ap- 
pearance, yet  she  could  never  avoid  lifting  her  foot  as  if  to  step  over  the  cat, 
when  it  seemed  to  be  lying  in  her  path. 

861.  The  acuteness  with  which  particular  Sensations  are  felt  is  influenced  in 
a  remarkable  degree  by  the  attention  they  receive  from  the  mind.     If  the  mind 
be  entirely  inactive,  as  in  profound  sleep,  no  sensation  whatever  is  produced  by 
ordinary  impressions ;  and  the  same  is  the  case  when  the  attention  is  so  com- 
pletely concentrated  upon  some  object  of  thought  or  contemplation  that  sensa- 
tions altogether  unconnected  with  it  fail  to  make  any  impression  on  the  percep- 
tive consciousness.     On  the  other  hand,  when  the  attention  is  from  any  cause 
strongly  directed  upon  them,  impressions  very  feeble  in  themselves  produce 
sensations  of  even  painful  acuteness ;  thus,  every  one  knows  how  much  a  slight 
itching  of  some  part  of  the  surface  may  be  magnified  by  the  direction  of  the 
thoughts  to  it,  whilst,  as  soon  as  they  are  forced  by  some  stronger  impression 
into  another  channel,  the  irritation  is  no  longer  felt ;  so,  too,  it  must  be  within 
the  experience  of  most  persons,  how  vividly  sounds  are  perceived  when  they 
break  in  upon  the  stillness  of  the  night,  being  increased  in  strength,  not  only 
by  the  contrast,  but  by  absorbing  the  whole  attention.     An  interesting  experi- 
ment is  mentioned  by  Miiller,  which  shows  how  completely  the  mind  may  be 
unconscious   of  impressions  communicated  to  it  by  one  organ  of  sense,  when 


856  OF   SENSATION,    AND   THE   ORGANS   OP   THE    SENSES. 

occupied,  even  without  a  distinct  effort  of  the  will,  by  those  received  through 
another.  If  we  look  at  a  sheet  of  white  paper  through  two  differently-colored 
glasses  at  the  same  time — one  being  placed  before  each  eye — the  resulting 
sensation  is  seldom  that  of  a  mixture  of  the  colors  :  if  the  experiment  be  tried 
with  blue  and  yellow  glasses,  for  example,  we  do  not  see  the  paper  of  a  uni- 
form green ;  but  the  blue  is  predominant  at  one  moment,  and  the  yellow  at 
another ;  or  blue  nebulous  spots  may  present  themselves  on  a  yellow  field,  or 
yellow  spots  on  a  blue  field.  We  perceive,  from  this  experiment,  that  the 
attention  may  not  only  be  directed  to  the  impressions  made  on  either  retina,  to 
the  complete  exclusion  of  those  of  the  other,  but  it  may  be  directed  to  those 
made  on  particular  spots  of  either.  This  may  be  noticed,  again,  in  the  process 
by  which  we  make  ourselves  acquainted  with  a  landscape  or  a  picture ;  if  our 
attention  be  directed  to  the  whole  field  of  vision  at  once,  we  see  nothing  dis- 
tinctly ;  and  it  is  only  by  abstracting  ourselves  from  the  contemplation  of  the 
greater  part  of  it,  and  by  directing  our  attention  to  smaller  portions  in  succes- 
sion that  we  can  obtain  a  definite  conception  of  the  details.  The  same  is  the 
case  in  regard  to  auditory  impressions ;  and  here  the  power  of  attention,  in 
causing  one  sensation  or  series  of  sensations  to  predominate  over  others  which 
are  really  more  intense,  is  often  most  remarkably  manifested.  When  we  are 
listening  to  a  piece  of  music  played  by  a  large  orchestra,  for  example,  we  may 
either  attend  to  the  combined  effect  of  all  the  instruments,  or  we  may  single 
out  any  one  part  in  the  harmony,  and  follow  this  through  all  its  mazes ;  and  a 
person  with  a  practised  ear  (as  it  is  commonly  but  erroneously  termed,  it  being 
not  the  ear,  but  the  mind,  that  is  practised),  can  even  distinguish  the  sound  of 
the  weakest  instrument  in  the  whole  band,  and  can  follow  its  strain  through  the 
whole  performance.  This  attention  to  a  single  element  can  only  be  given, 
however,  by  withdrawing  the  mind  from  the  perception  of  the  remainder ;  and 
a  musician  who  thus  listens,  will  have  very  little  idea  of  the  rest  of  the  har- 
monic parts,  or  of  the  general  effect.  In  fact,  when  the  mind  is  thus  directed, 
by  a  strong  effort  of  the  will,  into  a  particular  channel,  it  may  be  almost  con- 
sidered as  unconscious  quoad  any  other  impressions. 

862.  The  effects  of  attention  are  not  only  manifested  in  regard  to  the  sensa- 
tions which  are  excited  by  external  impressions,  but  also  in  respect  to  those 
which  originate  within  the  system.  Every  one  is  aware  how  difficult  it  is  to 
keep  the  body  perfectly  quiescent,1  especially  when  there  is  a  particular  motive 
for  doing  so,  and  when  the  attention  is  strongly  directed  to  the  object.  This  is 
experienced  even  whilst  a  photogenic  likeness  is  being  taken,  when  the  position 
is  chosen  by  the  individual,  and  a  support  is  adapted  to  assist  him  in  retaining 
it ;  and  it  is  still  more  strongly  felt  by  the  performers  in  the  "  tableau  vivans," 
who  cannot  keep  up  the  effort  for  more  than  three  or  four  minutes.  Now  it  is 
well  known  that,  when  the  attention  is  strongly  directed  to  an  entirely  different 
object  (when  we  are  listening,  for  example,  to  an  eloquent  sermon,  or  an  inte- 
resting lecture),  the  body  may  remain  perfectly  motionless  for  a  much  longer 
period ;  the  uneasy  sensations,  which  would  otherwise  have  induced  the  indi- 
vidual to  change  his  position,  not  being  perceived  :  but  no  sooner  is  the  dis- 
course ended,  than  a  simultaneous  movement  of  the  whole  audience  takes  place, 
every  one  then  becoming  conscious  of  some  discomfort,  which  he  seeks  to  re- 
lieve. This  is  the  case  also  in  regard  to  the  respiratory  sensation ;  for  it  may 
generally  be  observed  that  the  usual  reflex  movements  do  not  suffice  for  the 
perfect  aeration  of  the  blood,  and  that  a  more  prolonged  inspiration,  prompted 
by  an  uneasy  feeling,  takes  place  at  intervals;  but  under  such  circumstances  as 
those  just  alluded  to,  this  feeling  is  not  experienced  until  the  attention  ceases  to 
be  engaged  by  a  more  powerful  stimulus,  and  then  it  manifests  itself  by  the 

1  Of  course  the  movements  of  respiration  and  winking  are  left  out  of  the  question. 


OF   SENSATION   IN   GENERAL.  857 

deep  inspirations  which  accompany,  in   almost  every  individual,  the  general 
movement  of  the  body. 

863.  It  is  remarkable  that  not  merely  are  subjective  sensations,  like  all 
others,  rendered  more  intense  by  the  direction  of  the  attention  to  them,  but 
they  may  be  actually  called  into  existence  by  the  fixation  of  the  attention  on 
certain  parts  of  the  body;  still  more,  by  the  belief  in  the  existence  of  objective 
causes  for  such  sensations.  The  "  effects  of  mental  attention  on  bodily  organs" 
have  been  specially  pointed  out  by  Dr.  Holland;1  from  whose  examples  the 
following  may  be  cited  in  proof  of  the  foregoing  position.  "The  attention 
concentrated,  for  so  by  an  effort  of  will  it  may  be,  on  the  head  or  sensorium, 
gives  certain  feelings  of  tension  and  uneasiness,  caused  possibly  by  some  change 
in  the  circulation  of  the  part ;  though  it  may  be  an  effect,  however  difficult  to 
be  conceived,  on  the  nervous  system  it-self.  Persistence  in  this  effort,  which  is 
seldom  indeed  possible  beyond  a  short  time  without  confusion,  produces  results 
of  much  more  complex  nature,  and  scarcely  to  be  defined  by  any  common  terms 
of  language/'  "  Stimulated  attention  will  frequently  give  a  local  sense  of 
arterial  pulsation  where  not  frequently  felt,  and  create  or  augment  those  singing 
noises  in  the  ears,  which  probably  depend  on  the  circulation  through  the  capil- 
lary vessels."  "  A  similar  direction  of  consciousness  to  the  region  of  the  stomach 
creates  in  this  part  a  sense  of  weight,  oppression,  or  other  less  definite  uneasi- 
ness ;  and,  when  the  stomach  is  full,  appears  greatly  to  disturb  the  due  digestion 
of  the  food.  The  state  and  action  of  the  bowels  are  much  influenced  by  the 
same  cause."  A  peculiar  sense  of  weight  and  restlessness  approaching  to  cramp, 
is  felt  in  a  limb,  to  which  the  attention  is  particularly  directed.  So,  again,  if 
the  attention  be  steadily  directed  to  almost  any  part  of  the  surface  of  the  body, 
some  feeling  of  itching,  creeping,  or  tickling  will  soon  be  experienced.  The 
fact  that  sensations  may  be  modified  by  previous  beliefs,  which  must  be  within 
the  experience  of  every  one,  is  remarkably  illustrated  by  the  well-known  excla- 
mation of  Dr.  Pearson,  "  Bless  me !  how  heavy  it  is,"  when  he  first  poised  upon 
his  finger  the  globule  of  potassium  produced  by  the  battery  of  Davy ;  his  pre- 
conception of  the  coincidence  between  metallic  lustre  and  high  specific  gravity 
causing  him  to  feel  that  as  ponderous  which  the  unerring  test  of  the  balance 
determined  to  be  lighter  than  water.  Of  the  absolute  creation  of  subjective 
sensations  by  the  belief  in  the  existence  of  their  objective  causes,  the  two 
following  cases,  related  by  Prof.  Bennett,3  are  very  satisfactory  examples;  the 
effect  of  the  idea  not  being  limited  to  the  production  of  the  sensations,  but 
extending  itself  to  the  consequences  which  would  have  followed  those  sensations 
if  their  supposed  cause  had  been  real.  "A  clergyman  told  me  that  some  time 
ago  suspicions  were  entertained,  in  his  parish,  of  a  woman  who  was  supposed  to 
have  poisoned  her  newly-born  infant.  The  coffin  was  exhumed,  and  the  procu- 
rator-fiscal, who  attended  with  the  medical  men  to  examinee  the  body,  declared 
that  he  already  perceived  the  odor  of  decomposition,  which  made  him  feel 
faint,  and  in  consequence  he  withdrew.  But,  on  opening  the  coffin,  it  was 
found  to  be  empty ;  and  it  was  afterwards  ascertained  that  no  child  had  been 
born,  and  consequently  no  murder  committed."  The  second  case  is  yet  more 
remarkable.  "A  butcher  was  brought  into  the  shop  of  Mr.  Macfarlan,  the 
druggist,  from  the  market-place  opposite,  laboring  under  a  terrible  accident. 
The  man  on  trying  to  hook  up  a  heavy  piece  of  meat  above  his  head,  slipped, 
and  the  sharp  hook  penetrated  his  arm,  so  that  he  himself  was  suspended.  On 
being  examined,  he  was  pale,  almost  pulseless,  and  expressed  himself  as  suffer- 
ing acute  agony.  The  arm  could  not  be  moved  without  causing  excessive 

1  See  his  valuable  Essay  on  that  subject  in  his  "  Medical  Notes  and  Reflections,"  and  in 
Ms  "Chapters  on  Mental  Physiology." 

2  "The  Mesmeric  Mania  of  1851,"  Edinburgh,  1851. 


858      OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 

pain;  and  in  cutting  off  the  sleeve,  he  frequently  cried  out;  yet  when  the  arm 
was  exposed,  it  was  found  to  be  quite  uninjured,  the  hook  having  only  traversed 
the  sleeve  of  his  coat !"  In  this  and  similar  cases,  the  sensation  was  perfectly 
real  to  the  individual  who  experienced  it ;  but  it  originated  in  a  Cerebral 
(ideational)  change  which  produced  its  impression  through  the  nerves  of  internal 
sensation  (§  758),  instead  of  in  an  impression  upon  the  nerves  of  the  external 
senses  to  which  it  was  referred.  Of  this  kind  of  action  we  have  seen  other 
examples,  in  the  production  of  sensations  by  "  suggestion"  in  the  state  of  arti- 
ficial reverie  (§  825).  And  the  excitement  of  the  peculiar  sensation  of  tickling 
in  a  ticklish  person  by  any  movement  that  suggests  the  idea,  and  of  that  of 
creeping  or  itching  by  the  mention  of  bed-infesting  insects  to  those  who  are 
peculiarly  liable  to  their  attacks,  are  familiar  instances  of  the  same  fact ;  which 
strongly  confirms  the  general  doctrines  heretofore  advanced,  respecting  the 
analogy  between  the  peripheral  surface  of  the  Cerebrum  and  the  peripheral 
expansions  of  the  Sensory  nerves,  as  regards  their  mutual  relations  to  the  Sen- 
sorium  (§  753). 

2. — Sense  of  Touch. 

864.  By  the  sense  of  Touch,  as  commonly  understood,  is  meant  that  modi- 
fication of  the  common  sensibility  of  the  body,  of  which  the  cutaneous  surface 
is  the  especial  seat.  The  Skin  is  peculiarly  adapted  for  this  purpose,  not  merely 
by  the  large  amount  of  sensory  nervous  fibres  which  are  distributed  in  its  sub- 
stance, but  also  by  its  possession  of  a  papillary  apparatus  in  which  these  nerves 
terminate,  or  rather  commence.  The  papillse  are  little  elevations  of  the  surface 
of  the  cutis,  easily  perceptible  by  the  aid  of  a  lens ;  each  is  chiefly  composed 
of  a  vascular  loop  (Fig.  196),  in  close  relation  with  a  similar  loop  formed  by 
the  nervous  fibril ;  and  also  incloses  (as  appears  from  the  recent  researches  of 
Professors  Wagner  and  Kblliker)  an  "axile  body,"  composed  of  a  mass  of 
homogeneous  areolar  tissue  with  an  external  layer  of  imperfectly  developed 
elastic  tissue,  and  essentially  similar  to  the  bundles  of  fibrous  tissue  encircled 
by  elastic  fibres  which  are  to  be  found  in  the  cutis.  These  "  axile  bodies"  are 
only  to  be  found  in  the  papillae  of  those  parts  which  are  distinguished  for  acute- 
ness  of  tactile  sensibility;  and  hence  we  cannot  regard  them  as  essential  to  the 
exercise  of  the  sense  of  touch,  their  function  probably  being  to  intensify  tactile 

impressions,  where  delicacy  of  touch  is  peculiarly 
Fig.  196.  required.1     The  number  of  these  papillae  within 

any  given  area  pretty  closely  corresponds  with 
the  degree  of  sensibility  of  that  part  of  the  sur- 
face; thus  we  find  them  most  abundant  on  the 
hands,  especially  towards  the  points  of  the  fingers, 
and  on  the  lips  and  tongue.  Some  interesting 
observations  have  been  made  by  Prof.  Weber  on 
the  sensibility  of  different  parts  of  the  skin. 
His  mode  of  ascertaining  this  was  to  touch  the 
surface  with  the  legs  of  a  pair  of  compasses,  the 
Capillary  network  at  margin  of  lips,  points  of  which  were  guarded  with  pieces  of  cork ; 

the  eyes  being  closed  at  the  time,  the  legs  were 

approximated  to  each  other,  until  they  were  brought  within  the  smallest  distance 
at  which  they  could  be  felt  to  be  distinct  from  one  another,  which  has  been 

1  The  accounts  of  the  structure  of  the  tactile  papillse  given  by  Prof.  Kolliker  in  his 
"  Mikroskopische  Anatomic,"  band  ii.  p.  24,  and  in  the  "  Zeitschrift  fur  Wissenschaften 
Zoologie,"  band  iv.  heft  1,  1852,  are  here  followed.  For  a  notice  of  the  peculiar  views  of 
Prof.  Wagner,  see  the  "Brit,  and  For.  Med.-Chir.  Rev.,"  vol.  x.  p.  251  [or  \  343— ED.]. 


SENSE   OF   TOUCH. 


859 


termed  by  Dr.-  Graves  "  the  limit  of  confusion." 
the  results  of  his  experiments : — 


The  following  are  some  of 


Point  of  tongue        .         .         .     J  of  a  line. 
Palmar  surface  of  third  phalanx  1  line. 
Red  surface  of  lips  .         .         .2  lines. 
Palmar  surface  of  second  phalanx  2 
Dorsal  surface  of  third  phalanx    3 
Palmar  surface  of  metacarpus      3 
Tip  of  the  nose        .         .         .3 
Dorsum  and  edge  of  tongue     .     4 
Part  of  lips  covered  by  skin    .     4 
Palm  of  hand  .         .         .5 

Skin  of  cheek  .  .  .5 
Extremity  of  great  toe  .  .  5 
Hard  palate  .  .  .  .6 
Dorsal  surface  of  first  phalanx  7 
Dorsum  of  hand  .  .  .8 


Mucous  membrane  of  gums 
Lower  part  of  forehead 
Lower  part  of  occiput 
Back  of  hand     . 
Neck,  under  lower  jaw 
Vertex       .         .         .         . 
Skin  over  patella 


Dorsum  of  foot  < 
Skin  over  sternum 
Skin  beneath  occiput 
Skin  over  spine,  in  back 
Middle  of  the  arm 
thigh   . 


9  lines. 
10 
12 
14 
15 
15 
16 
18 
18 
18 
20 
24 
30 
30 
30 


It  is  curious  that  the  distance  between  the  legs  of  the  compasses  seemed  to  be 
greater  (although  really  so  much  less),  when  it  was  felt  by  the  more  sensitive 
parts,  than  when  it  was  estimated  by  parts  of  less  distinct  sensibility.  With 
the  extremities  of  the  fingers  and  the  point  of  the  tongue,  the  distance  could  be 
distinguished  most  easily  in  the  longitudinal  direction;  on  the  dorsum  of  the 
tongue,  the  face,  neck,  and  extremities,  the  distance  could  be  recognized  best 
when  the  points  were  placed  transversely.  As  a  general  fact,  it  seems  that  the 
sensibility  of  the  trunk  is  greater  on  the  median  line,  both  before  and  behind, 
and  less  at  the  sides.  Differences  in  the  temperature  and  weight  of  bodies  were, 
according  to  Prof.  Weber's  observations,  most  accurately  recognized  at  the  parts 
which  were  determined  to  be  most  sensible  by  the  foregoing  method  of  inquiry.1 
865.  As  already  stated  (§  855),  the  only  idea  communicated  to  our  minds 
by  the  sense  of  Touch,  when  exercised  in  its  simplest  form,  is  that  of  Resist- 
ance; and  it  is  by  the  various  degrees  of  resistance  which  the  sensory  surface 
encounters,  of  which  we  partly  judge  by  the  muscular  sense  (§  750),  that  we 
estimate  the  hardness  or  softness  of  the  body  against  which  we  press.  It  is 
only  when  either  the  sensory  surface  or  the  substance  touched  is  made  to  change 
its  place  in  regard  to  the  other,  that  we  obtain  the  additional  notion  of  extension 
or  space;  this  also  being  derived  from  the  combination  of  the  muscular  with  the 
tactile  sense.  By  the  impressions  made  upon  the  papillae,  during  the  move- 
ment of  the  tactile  organ  over  the  body  which  is  being  examined,  the  rough- 
ness, smoothness,  or  other  peculiar  characters  of  the  surface  of  the  latter  are 
estimated.  Our  knowledge  of  form,  however,  is  a  very  complex  process,  requir- 
ing not  merely  the  exercise  of  the  sense  of  touch,  but  also  great  attention  to 
the  muscular  sensations.  —  It  is  chiefly,  as  formerly  remarked,  in  the  variety  of 
movements  of  which  the  hand  of  Man  is  capable,  that  it  is  superior  to  that  of 
any  other  animal  ;  and  it  cannot  be  doubted  that  the  sense  of  Touch,  thus  em- 
ployed, affords  us  a  very  important  means  of  acquiring  information  in  regard  to 
the  external  world,  and  especially  of  correcting  many  vague  and  fallacious 

1  See  his  Memoir  "De  Pulsu,  Respiratione,  Auditu,  et  Tactu,"  Lipsise,  1834.  This 
method  of  inquiry  has  been  since  pursued  by  M.  H.  Belfield-Lefevre  ("Recherches  sur  la 
Nature,  la  Distribution,  et  1'Organ  du  Sens  Tactile,"  Paris,  1837),  and  by  Prof.  Valentin 
("Lehrbuch  der  Physiologic  des  Menschen,"  band  ii.  \  566),  with  the  same  general 
results.  It  was  found  by  Prof.  Valentin,  however,  that  a  considerable  amount  of  indi- 
vidual variation  exists  in  regard  to  the  "limit  of  confusion;"  some  persons  being  able  to 
distinguish  the  points  at  one-half  or  even  one-third  of  the  distances  -required  by  others.  — 
In  the  Author's  article  "Touch"  in  the  "Cyclopaedia  of  Anatomy  and  Physiology,"  vol.  iv. 
p.  1169,  will  be  found  a  Table  including  the  whole  series  of  observations  made  by  Profrs. 
Weber  and  Valentin,  the  maxima,  and  minima  of  the  latter  being  stated,  as  well  as  the 
means. 


860  OF   SENSATION,   AND   THE   ORGANS   OF   THE    SENSES. 

notions  which  we  should  derive  from  the  sense  of  Sight,  if  used  alone.  On  the 
other  hand,  it  must  be  confessed  that  our  knowledge  would  have  a  very  limited 
range,  if  this  sense  were  the  only  medium  through  which  we  could  acquire 
ideas.  It  is  probably  on  the  sensations  communicated  through  the  Touch,  that 
the  idea  of  the  material  world,  as  something  external  to  ourselves,  chiefly  rests ; 
but  this  idea  is  by  no  means  a  logical  deduction  from  our  experience  of  these 
sensations,  being  rather  an  instinctive  or  intuitive  perception  directly  excited 
by  them  (§  790). 

866.  That  the  conditions  under  which  certain  of  the  modifications  of  common 
sensation  operate,  are  in  some  respects  different  from  those  of  ordinary  Touch, 
is  very  easily  shown.  Thus,  the  feeling  of  tickling  is  excited  most  readily  in 
parts  which  have  but  a  low  tactile  sensibility,  namely,  the  armpits,  flanks,  and 
soles  of  the  feet;  whilst  in  the  points  of  the  fingers,  whose  tactile  sensibility  is 
most  acute,  it  cannot  be  excited.  Moreover,  the  nipple  is  very  moderately 
endowed  with  ordinary  sensibility;  yet  by  a  particular  kind  of  irritation,  a  very 
strong  feeling  may  be  excited  through  it. — Again,  in  regard  to  Temperature,  it 
is  remarked  by  Weber  that  the  left  hand  is  more  sensitive  than  the  right : 
although  the  sense  of  touch  is  undoubtedly  the  more  acute  in  the  latter.  He 
states  that,  if  the  two  hands,  previously  of  the  same  temperature,  be  plunged 
into  separate  basins  of  warm  water,  that  in  which  the  left  hand  is  immersed 
will  be  felt  as  the  warmer,  even  though  its  temperature  is  somewhat  lower  than 
that  of  the  other.  In  regard  to  the  sensations  of  heat  and  cold,  he  points  out 
another  curious  fact — that  a  weaker  impression  made  on  a  large  surface, 
seems  more  powerful  than  a  stronger  impression  made  on  a  small  surface ; 
thus,  if  the  forefinger  of  one  hand  be  immersed  in  water  at  104°,  and 
the  whole  of  the  other  hand  be  plunged  in  water  at  102°,  the  cooler  water 
will  be  thought  the  warmer ;  whence  the  well-known  fact  that  water  in  which  a 
finger  can  be  held  will  scald  the  whole  hand.  Hence  it  also  follows  that  minute 
differences  in  temperature,  which  are  imperceptible  to  a  single  finger,  are  appre- 
ciated by  plunging  the  whole  hand  into  the  water ;  in  this  manner,  a  difference 
of  one-third  of  a  degree  may  readily  be  detected,  when  the  same  hand  is  placed 
successively  in  two  vessels.  The  judgment  is  more  accurate,  when  the  temper- 
ature is  not  much  above  or  below  the  usual  heat  of  the  body  ;  just  as  sounds  are 
best  discriminated  when  neither  very  acute  nor  very  grave. — Some  further 
experiments  have  recently  been  made  by  Professor  Weber,  to  determine  whether 
the  sense  of>  temperature  is  received  through  any  other  channel  than  the  sensory 
apparatus  contained  in  the  integuments.1  The  first  means  of  which  he  availed 
himself  for  deciding  this  question,  was  that  afforded  by  the  results  of  accident 
or  surgical  operations,  in  which  a  portion  of  skin  had  been  left  deficient.  Thus, 
in  three  cases  in  which  a  large  portion  of  the  skin  had  been  destroyed  by  a  burn, 
and  in  which  healing  had  not  advanced  so  far  as  to  renew  the  organ  of  touch,  it 
was  found  that  no  correct  discrimination  could  be  made  between  two  spatulas, 
one  of  them  at  a  temperature  of  from  48°  to  54°,  the  other  of  from  113°  to  122°, 
which  were  brought  into  contact  with  the  denuded  surface  ;  so  that  one  of  these 
patients  thrice  affirmed  that  he  was  being  touched  with  the  cold  body,  when  it 
was  the  warm,  and  the  reverse.  But  when  the  spatula  was  in  one  instance 
made  somewhat  warmer,  and  was  brought  into  contact  with  the  unskinned  sur- 
face, the  patient  felt,  not  heat,  but  pain.  Another  means  of  gaining  information 
on  this  point  is  afforded  by  the  ingestion  or  injection  of  a  large  quantity  of  warm 
or  cold  fluid  into  the  stomach  or  intestinal  canal.  Thus  Professor  Weber  states 
that,  after  drinking  a  tumbler  of  water  at  32°,  he  felt  the  cold  water  in  the  mouth, 
in  the  palate,  and  in  the  pharynx,  as  far  as  the  limits  of  the  sense  of  touch ; 
but  that  the  gradual  passage  of  the  cold  water  into  the  stomach  could  not  be 

i  "Miiller's  Archiv.,"  1849,  heft  iv.  s.  273-283. 


SENSE   OF   TOUCH.  861 

perceived.  There  was,  it  is  true,  a  slight  sensation  of  cold  in  the  gastric  region ; 
but,  as  it  only  occupied  the  situation  of  the  anterior  wall  of  the  stomach,  it  was 
attributable  to  the  abstraction  of  heat  from  the  abdominal  integuments  in  con- 
tact with  this.  In  an  opposite  experiment,  the  author  drank  quickly  three 
glasses  of  milk,  the  temperature  of  the  first  of  which  was  158°,  that  of  the  second 
145°,  whilst  that  of  the  third  was  intermediate  between  the  two.  The  sensation 
of  heat  could  not  be  traced  lower  down  than  that  of  the  cold  in  the  previous  ex- 
periment. At  the  moment  when  the  fluid  entered  the  stomach,  there  was  a 
feeling  which  remained  for  some  time,  but  which  could  not  be  distinguished  as 
heat,  being  mistakable  for  cold.  In  order  to  ascertain  the  sensation  produced 
in  the  large  intestine  by  cold  water,  an  injection  of  14  ounces  of  water  of  the 
temperature  of  65°  was  thrown  up  the  rectum }  but  scarcely  any  sensation  of 
cold  could  be  perceived  from  it.  In  another  instance,  21  ounces  of  water  at 
the  same  temperature  were  thrown  up,  without  any  resulting  sensation  of  cold. 
In  both  these  cases,  on  the  return  of  the  enema  a  few  minutes  afterwards,  a 
distinct  feeling  of  cold  was  experienced  at  the  anus.  When  water  of  so 
low  a  temperature  as  45 J°  was  injected,  the  first  feeling  excited  was  a 
sensation  of  cold  in  the  immediate  neighborhood  of  the  anus,  and  then  a  feeble 
movement  in  the  bowels;  but  a  little  time  afterwards,  there  was  a  faint  sensation 
of  cold,  especially  in  the  anterior  wall  of  the  abdomen.  This  sensation,  how- 
ever, remained  after  the  return  of  the  water ;  and  may  hence  be  attributed  to 
the  abstraction  of  warmth  from  the  abdominal  integuments,  which  was  proved 
to  take  place,  the  temperature  of  the  surface  being  lowered  3°.  So,  again,  if 
the  cavity  of  the  nose  be  filled  with  cold  water,  the  coldness  is  only  perceived 
in  the  parts  of  the  cavity  which  are  most  endowed  with  the  proper  tactile  sense, 
namely,  the  neighborhood  of  the  nostrils  and  of  the  pharynx ;  and  it  is  not  all 
discernible  in  the  higher  part  of  the  cavity,  which  is  especially  subservient  to 
the  olfactory  sense.  But  when  the  water  injected  is  very  cold  (e.  g.  41°),  a 
peculiar  pain  is  felt  in  the  upper  part  of  the  nasal  fossse,  extending  to  the  re- 
gions of  the  forehead  and  the  lachrymal  canals ;  this  pain,  however,  is  altogether 
different  from  the  sense  of  coldness. — From  the  foregoing  experiments,  it  ap- 
pears fair  to  conclude  that  the  sensory  nerves  have  no  power  of  receiving  im- 
pressions indicative  of  difference  of  temperature,  unless  those  impressions  are 
communicated  through  a  special  organ  ;  but  they  afford  no  adequate  ground  for 
the  supposition  that  a  set  of  nerve-fibres  is  provided  for  their  transmission,  dis- 
tinct from  those  which  minister  to  common  sensation.  This  conclusion  is  confirmed 
by  the  fact  that  we  cannot  excite  impressions  of  heat  or  cold  by  direct  applica- 
tion to  the  trunks  of  nerves  which  we  know  must  conduct  such  impressions ;  for 
the  parts  of  the  skin,  immediately  beneath  which  lie  large  nerve-trunks,  are 
not  more  sensitive  to  moderate  heat  or  cold  than  are  any  others ;  whilst  a  greater 
degree  of  either  is  felt  as  pain,  not  as  a  change  of  temperature.  Thus,  a 
mixture  of  ice  and  water,  applied  over  the  ulnar  nerve,  affects  it  in  fifteen 
seconds,  and  produces  severe  pain,  having  no  resemblance  to  cold,  such  as  cannot 
be  excited  by  the  same  cold  applied  to  any  other  region.  So  the  nerve  of  the 
tooth-pulp  is  equally  and  similarly  affected  by  water  of  43°  and  of  112°  ;  either 
application  causing  a  pain  exactly  similar  to  that  excited  by  the  other,  or  to 
that  produced  by  pressure.  The  same  is  true  of  the  impressions  received  through 
the  skin  itself,  when  they  pass  beyond  certain  limits  of  intensity ;  thus,  the 
sensation  produced  by  touching  frozen  mercury  is  said  to  be  not  distinguishable 
from  that  which  results  from  touching  a  red-hot  iron. 

867.  The  improvement  in  the  sense  of  Touch,  in  those  persons  whose  depend- 
ence upon  it  is  increased  by  the  loss  of  other  senses,  is  well  known ;  this  is 
doubtless  to  be  in  part  attributed  (as  already  remarked)  to  the  increased 
attention  which  is  given  to  the  sensations,  and  in  part,  it  may  be  surmised,  to 
an  increased  development  of  the  tactile  organs  themselves,  resulting  from  the 


OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 

frequent  use  of  them.  The  process  of  the  acquirement  of  the  power  of  recog- 
nizing elevated  characters  by  the  touch,  is  a  remarkable  example  of  this  im- 
provability.  When  a  blind  person  first  commences  learning  to  read  in  this 
manner,  it  is  necessary  to  use  a  large  type  :  and  every  individual  letter  must 
be  felt  for  some  time,  before  a  distinct  idea  of  its  form  is  acquired.  After  a 
short  period  of  diligent  application,  the  individual  becomes  able  to  recognize 
the  combination  of  letters  in  words  without  forming  a  separate  idea  of  each  letter ; 
and  can  read  line  after  line,  by  passing  the  finger  over  each,  with  considerable 
rapidity.  When  this  power  is  once  thoroughly  acquired,  the  size  of  the  type 
may  be  gradually  diminished ;  and  thus  blind  persons  may  bring  themselves, 
by  sufficient  practice,  to  read  a  type  not  much  larger  than  that  of  an  ordinary 
large-print  Bible.  The  case  of  Saunderson,  who,  although  he  lost  his  sight  at 
two  years  old,  became  Professor  of  Mathematics  at  Cambridge,  is  well  known ; 
amongst  his  most  remarkable  faculties,  was  that  of  distinguishing  genuine  medals 
from  imitations,  which  he  could  do  more  accurately  than  many  connoisseurs  in 
full  possession  of  their  senses.  Several  instances  are  recorded  of  men  who  be- 
came eminent  as  Sculptors  after  the  loss  of  their  sight,  and  who  were  particularly 
successful  in  modelling  portrait-busts  :  here,  it  is  obvious,  not  merely  the  tactile, 
but  the  muscular  sensibility  must  be  greatly  augmented  in  acuteness  by  the 
habit  of  attention  to  it.  The  power  of  immediate  recognition  of  individuals  by 
the  slightest  contact  of  the  hands,  even  after  long  periods  of  time,  which  most 
blind  and  deaf  persons  have  displayed,  is  one  of  the  most  curious  examples  of 
the  mode  in  which  tactual  perceptions  will  impress  themselves  on  the  memory, 
when  they  are  habitually  attended  to.  As  an  example  of  the  correct  notions 
which  may  be  conveyed  to  the  mind,  of  the  forms  and  surfaces  of  a  great  variety 
of  objects,  and  of  the  sufficiency  of  these  notions  for  accurate  comparison,  the 
Author  may  mention  the  case  of  a  blind  friend  of  his  own,  who  has  acquired  a 
very  complete  knowledge  of  Conchology,  both  recent  and  fossil;  and  who  is  not 
only  able  to  recognize  every  one  of  the  numerous  specimens  in  his  own  cabinet, 
but  to  mention  the  nearest  alliances  of  a  shell  previously  unknown  to  him,  when 
he  has  thoroughly  examined  it  by  his  touch.  Many  similar  instances  might  be 
cited,  one  of  the  most  remarkable  being  that  of  John  Gough,  who,  though  blind, 
was  a  noted  botanical  collector,  and  earned  his  livelihood  as  a  land-surveyor. 
Several  cases  are  on  record,1  of  the  acquirement,  by  the  blind,  of  the  power  of 
distinguishing  the  colors  of  surfaces,  which  were  similar  in  other  respects;  and, 
however  wonderful  this  may  seem,  it  is  by  no  means  incredible.  For  it  is  to  be 
remembered  that  the  difference  of  color  depends  upon  the  position  and  arrange- 
ment of  the  particles  composing  the  surface,  which  render  it  capable  of  reflecting 
one  ray  whilst  it  absorbs  all  the  rest ;  and  it  is  .  quite  consistent  with  what  we 
know  from  other  sources,  to  believe  that  the  sense  of  Touch  may  become  so  re- 
fined as  to  communicate  a  perception  of  such  differences.3 

3. — Sense  of  Taste. 

868.  The  sense  of  Taste  is  that  by  which  we  distinguish  the  sapid  properties 
of  bodies.  The  term,  as  commonly  understood,  includes  much  more  than  this ; 
being  usually  employed  to  designate  the  whole  of  that  knowledge  of  the  qualities 
of  a  body  (except  such  as  is  purely  tactile),  which  we  derive  through  the  sen- 
sory apparatus  situated  within  the  mouth.  But  it  will  be  hereafter  shown  that  a 

1  Among  the  best  authenticated  of  these  is  that  of  a  lady  who  became  blind,  and  after- 
wards deaf,  in  consequence  of  an  attack  of  confluent  smallpox  ;  cited  in  Dr.  Kitto's  "Lost 
Senses,"  vol.  ii.  p.  79,  from  the  "Annual  Register"  for  1758. — Dr.  Kitto's  treatise  may 
be  referred  to,  as  containing  a  large  collection  of  interesting  cases  of  a  similar  description. 

2  For  some  additional  details  in  regard  to  the  sense  of  Touch,  see  the  Author's  article 
"Touch,"  in  the  "Cyclopaedia  of  Anatomy  and  Physiology,"  vol.  iv. 


SENSE   OF   TASTE.  863 

considerable  part  of  this  is  dependent  upon  the  assistance  of  the  olf active  sense; 
which  is  affected  through  the  posterior  nares  by  the  odorous  emanations  of  all 
such  bodies  as  are  capable  of  giving  them  off ;  and  the  indications  of  which  are 
so  combined  with  those  of  the  true  gustative  sense  as  to  make  an  apparently 
single  impression  upon  the  sensorium.  Moreover,  there  are  certain  sensorial 
impressions  received  through  the  organ  of  taste,  which  are  so  nearly  allied  in 
their  character  to  those  of  touch  as  to  render  it  difficult  to  specify  any  fun- 
damental difference  between  them :  such  are  the  pungent  sensations  produced  by 
mustard,  pepper,  the  essential  oils,  &c. ;  all  of  which  substances  produce  a  sen- 
sation when  applied  for  a  sufficient  length  of  time  to  any  part  of  the  cutaneous 
surface,  which  can  scarcely  be  distinguished  from  that  excited  through  the  organ 
of  taste,  in  any  other  way  than  by  its  inferior  intensity,  and  by  the  absence  of 
the  concurrent  odorous  emanations.  The  taste  of  such  substances  might,  perhaps, 
be  considered,  therefore,  as  the  composite  result  of  the  impressions  made  upon 
the  sensorium  through  a  refined  and  acute  touch,  and  by  the  effect  of  their  odor- 
ous emanations  upon  the  organ  of  smell.  After  making  full  allowance,  however, 
for  all  such  as  can  be  thus  accounted  for,  there  remains  a  large  class  of  pure 
sapdrsj  of  which  we  take  cognizance  without  the  assistance  of  smell,  and  which 
are  altogether  dissimilar  to  any  tactile  impressions ;  such  are  the  bitter  of  qui- 
nine, the  sour  of  tartaric  acid,  the  sweet  of  sugar,  the  saline  of  common  salt, 
&c.  The  smell  can  give  us  no  assistance  in  distinguishing  small  particles  of 
these  bodies,  since  they  are  either  entirely  inodorous,  or  so  nearly  so  as  only  to 
be  recognizable  through  its  means  when  in  large  masses ;  and  the  most  refined 
touch  cannot  afford  any  indication  of  that  kind  of  difference  among  them,  of 
which  we  are  at  once  rendered  cognizant  by  taste. — Of  all  the  "special"  senses, 
however,  that  of  Taste  is  most  nearly  allied  to  that  of  touch,  as  appears  from 
several  considerations.  In  the  first  place,  the  actual  contact  of  the  object  of 
sense  with  the  organ  through  which  the  impression  is  received  is  necessary  in 
the  present  case,  as  in  the  preceding.  Again,  it  appears,  from  the  considerations 
formerly  adduced  (§  717),  that  there  is  no  special  nerve  of  Taste ;  for  the  gus- 
tative impressions  upon  the  front  of  the  tongue  are  conveyed  by  the  Lingual 
branch  of  the  5th  Pair,  which  also  ministers  to  common  sensibility ;  whilst 
those  made  upon  the  back  of  the  organ  are  conveyed  by  the  G-losso-pharyngeal, 
which  also  ministers  to  common  sensibility ;  and  pressure  on  the  trunk  of  either 
of  these  nerves  gives  rise  to  pain,  which  is  not  the  case  with  either  the  olfactory, 
the  optic,  or  the  auditory  nerves.  Moreover,  the  papillary  apparatus,  through 
which  the  gustative  impressions  are  made  upon  the  extremities  of  these  nerves, 
is  essentially  the  same  in  structure  with  that  of  the  skin. — But  for  the  gustative 
nerve-fibres  to  be  impressed  by.  the  distinctive  properties  of  sapid  substances,  it 
seems  requisite  that  these  substances  should  be  brought  into  immediate  relation 
with  them,  and  that  they  should  penetrate,  in  the  state  of  solution,  through  the 
investments  of  the  papillae,  into  their  substance.  This  would  seem  to  be  proved 
by  the  two  following  facts  :  first,  that  every  substance  which  possesses  a  distinct 
taste  is  more  or  less  soluble  in  the  fluids  of  the  mouth,  whilst  substances  which 
are  perfectly  insoluble  do  not  make  their  presence  known  in  any  other  way  than 
through  the  sense  of  touch ;  and,  second,  that  if  the  most  sapid  substance  be 
applied  in  a  dry  state  to  the  papillary  surface,  and  this  be  also  dry,  no  sensation 
of  taste  is  excited.  Hence  it  may  be  inferred  that,  in  the  reception  of  gus- 
tative impressions,  a  change  is  produced  in  the  molecular  condition  of  the  nerve-* 
fibres,  or,  to  use  the  language  of  Messrs.  Todd  and  Bowman,  their  polarity  is 
excited  by  the  direct  agency  of  the  sapid  matter  itself.  This  change  may  be 
induced,  however,  both  by  electrical  and  mechanical  stimulation.  If  we  make 
the  tongue  form  part  of  a  galvanic  circuit,  a  peculiar  sensation  is  excited,  which 
is  certainly  allied  rather  to  the  gustative  than  to  the  tactile,  and  which  does  not 
seem  to  be  due  (as  was  at  one  time  supposed)  to  the  decomposition  of  the  salts 


864 


OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 


of  the  saliva.  And,  as  Dr.  Baly  has  pointed  out,1  "if  the  end  of  the  finger 
be  made  to  strike  quickly,  but  lightly,  the  surface  of  the  tongue  at  its  tip,  or 
its  edge  near  the  tip,  so  as  to  affect  not  the  substance  of  the  organ,  but  merely 
the  papillae,  a  taste  sometimes  acid,  sometimes  saline,  like  the  taste  produced  by 
electricity,  will  be  distinctly  perceived.  The  sensation  of  taste  thus  induced 
will  sometimes  continue  several  seconds  after  the  application  of  the  mechanical 
stimulus."  On  the  other  hand,  as  Wagner  has  truly  remarked,  if  the  surface 
of  the  tongue  near  the  root  be  touched  with  a  clean  dry  glass  rod,  or  a  drop  of 
distilled  water  be  placed  upon  it,  a  slightly  bitterish  sensation  is  produced ;  and 
this,  if  the  pressure  be  continued,  passes  into  that  of  nausea,  and,  if  the  pres- 
sure be  increased,  even  excites  vomiting.  The  feeling  of  nausea  may  be  excited 
by  mechanical  irritation  of  any  part  of  the  surface  of  the  fauces  and  soft  palate ; 
and  this  feeling  is  certainly  much  more  allied  to  that  of  taste  than  to  that  of 
touch.  Further,  it  has  been  observed  by  Henle  that,  if  a  small  current  of  air 
be  directed  upon  the  tongue,  it  gives  rise  to  a  cool  saline  taste  like  that  of  salt- 
petre. Thus  we  find  that  the  peculiar  effects  of  sapid  substances  upon  the 
nerves  of  taste  may  be  imitated  to  a  certain  extent  by  other  agencies  ;  and  it 

also  appears  that  the  sensations  excited 

Fig.  197.  by  these  vary  according  to  the  part  of 

the  gustative  surface  on  which  they 
operate ;  mechanical  or  electrical  stimu- 
lation of  the  front  of  the  tongue  giving 
rise  to  a  kind  of  saline  taste,  whilst 
mechanical  stimulation  applied  to  the 
back  of  the  tongue  and  fauces  excites 
the  feelings  of  bitterness  and  nausea. — 
One  of  the  conditions  requisite  for  the 
due  exercise  of  the  gustative  sense  is  a 
temperature  not  departing  far  on  either 
side  from  that  which  is  natural  to  the 
body.  It  appears  from  the  recent  ex- 
periments of  Prof.  E.  H.  Weber,3  that  if 
the  tongue  be  kept  immersed  for  nearly 
a  minute  in  water  of  about  125°,  the 
taste  of  sugar  brought  in  contact  with 
it,  either  in  powder  or  solution,  is  no 
longer  perceived ;  the  sense  of  touch, 
usually  so  delicate  at  the  tip  of  the 
tongue,  being  also  rendered  imperfect. 
A  similar  imperfection  of  taste  and 
touch  was  produced  by  immersing  the 
tongue  for  the  same  length  of  time  in 
a  mixture  of  water  and  broken  ice. 

869.  The  surface  of  the  tongue  is 
undoubtedly  the  special  seat  of  gusta- 
tive sensibility  in  Man;  though  the 
sense  of  Taste  is  not  by  any  means 
restricted  to  that  organ,  being  diffused 
in  a  less  degree  over  the  soft  palate, 
the  arches  of  the  palate,  and  the  fauces. 
It  is  on  the  Tongue  alone,  however, 
that  the  papillary  apparatus  is  fully 


Tongue  seen  on  its  upper  surface :  a.  One  of  the 
"circumvallate  papillae.  6.  One  of  the  fungiform 
papillae.  Numbers  of  the  conical  papillae  are  seen 
about  d,  and  elsewhere,  e.  Glottis,  epiglottis,  and 
glosso-epiglottidean  folds  of  mucous  membrane. — 
From  Soemmering. 


1  Translation  of  "Miiller's  Physiology,"  p.  1062,  note. 

2  "Muller's  Arclriv.,"  1847,  S.  342. 


SENSE   OP   TASTE. 


865 


developed ;  and  its  structure  has  been  so  carefully  examined  and  described  by 
Messrs.  Todd  and  Bowman,1  that  little  remains  to  be  added  to  their  account 
of  it. — The  lingual  papillae  may  be  divided,  in  the  first  place,  into  the  Simple 
and  the  Compound;  the  former  of  which  had  previously  escaped  observation, 
through  not  forming  any  apparent  projection.  The  Simple  papillae  (Fig.  198) 

Fig.  198. 


Simple  papillae  near  the  base  of  the  tongue :  A.  a,  concealed  tinder  the  epithelium ;  b,  uncovered  by  it. — 
Magnified  10  diameters.  B.  a.  Arterial  twig,  supplying  their  capillary  loops,  v.  Vein.  The  vessels  are  all 
contained  within  the  line  b,  b,  of  basement-membrane,  c,  c.  Deeper  epithelial  particles  resting  on  the  base- 
ment-membrane, d.  Scaly  epithelium  on  the  surface.  The  granular  interior  of  the  papillae  is  represented  at 
e.  c.  Papillae  in  which  the  basement-membrane  is  not  visible ;  and  the  deep  layer  of  epithelium  seems  to 
rest  on  the  capillary  loop.— Magnified  200  diameters. 


Fig.  199. 


Vertical  section  of  one  of  the  circumvallate  papillae  :  a. 
Central  part,  b,  b.  Border,  c,  c.  Fissure  between  centre 
and  border.  The  secondary  papillae  are  seen  covered  by 
the  epithelium.  Similar  papillae  are  seen,  d,  d,  on  the 
membrane  beyond. — Magnified  8  diameters. 


are  scattered  in  the  intervals  of  the  compound,  over  the  general  surface  of  the 
tongue ;  and  they  occupy  much  of  the  surface  behind  the  circumvallate  variety, 
where  no  compound  papillae  exist.  They  are  completely  buried  and  concealed 
beneath  the  continuous  sheet  of  epithelium,  and  can  only  be  detected  when  this 
membrane  has  been  removed  by  maceration  ;  they  are  then  found  to  have  the 
general  characters  of  the  cutaneous  papillae,  but  nerve-tubes  have  not  yet  been 
detected  in  them.  The  Compound  papillae  are  visible  to  the  naked  eye ;  and 
have  been  classified,  according  to  their  shape,  into  the  circumvallate,  the  fungi- 
form,  and  the  filiform.  The  circumvallate  or  calyciform  papillae  (Fig.  199), 
are  eight  or  ten  in  number,  and  are  situated  in  a  Y-shaped  line  at  the  base  of 
the  tongue.  Each  consists  of  a  central  flattened  circular  projection  of  the 
mucous  membrane,  surrounded  by  a  tumid  ring  of  about  the  same  elevation, 
from  which  it  is  separated  by  a  narrow  circular  fissure.  The  surface  of  both 
centre  and  border  is  smooth,  and  invested  by  a  scaly  epithelium,  which  con- 
ceals a  multitude  of  simple  papillae.  The  funyiform  papillae  (Figs.  201,  204,  A) 
are  scattered  singly  over  the  tongue,  chiefly  upon  its  sides  and  tip.  They  pro- 


55- 


Physiological  Anatomy  and  Physiology  of  Man,"  p.  380,  Am.  Ed. 


OP  SENSATION,  AND  THE  ORGANS  OP  THE  SENSES 
Fig.  200. 


A.  Compound  papillae  on  the  side  of  the  foramen  caecum,  injected :  a,  a.  Arterial  twigs,    v,  v.  Veins.    The 
capillary  loops  indicate  the  simple  papillae ;  in  one  of  which,  b,  the  injected  matter  has  been  extravasated 
within  the  basement-membrane  of  the  papillae,  the  outline  of  which  is  thus  distinguished,    c.  Capillary 
plexus,  where  no  papillae  exist.    e}  e.  External  surface  of  the  epithelium  of  the  papillae. — Magnified  15 
diameters. 

B.  One  of  the  simple  papillae  of  A :  a,  v,  v.  Arterial  and  venous  sides  of  the  capillary  loops,    b,  b.  Basement- 
membrane,    d.  Deeper  epithelial  particles  resting  on  the  basement-membrane,    s.  Scaly  epithelium  on  the 
surface.    Magnified  300  diameters. 

Fig.  201. 


A.  Fungiform  papilla,  showing  the  secondary  papillae  on  its  surface,  and  at  a  its  epithelium  covering  them 
over. — Magnified  35  diameters. 

B.  Another,  with  the  capillary  loops  of  its  simple  papillae  injected,   a.  Artery,    v.  Vein.    The  groove  around 
the  base  of  some  of  the  fungiform  papillae  is  here  represented  as  well  as  the  capillary  loops,  c,  c,  of  some  neigh- 
boring simple  papillae.— Magnified  18  diameters. 

ject  considerably  from  the  surface,  and  are  usually  narrower  at  their  base  than 
at  their  summit.  They  contain  a  complex  capillary  plexus  (Fig.  202),  the 
terminal  loops  of  which  enter  the  numerous  simple  papillae  that  clothe  the  sur- 
face of  the  fungiform  body.  Amidst  these  lie  nerve-tubes,  which  probably 
have  a  looped  arrangement  j1  and  the  epithelium  which  covers  them  is  so  thin 
as  to  allow  the  red  color  of  the  blood  to  be  seen  through  it.  In  this  manner, 

1  The  Author,  in  conjunction  with  Messrs.  Bowman,  T.  Wharton  Jones,  and  Kiernan, 
has  most  carefully  examined  the  mode  of  termination  of  the  nerves  in  the  fungiform  papil- 
lae, with  the  view  of  testing  the  validity  of  the  assertion  of  Dr.  Waller  ("  Phil.  Trans.," 
1849)  that  they  have  free  truncated  extremities.  No  such  terminations,  however,  could 
be  exhibited  to  them  by  Dr.  Waller ;  and  the  conclusion  at  which  they  arrived  as  most 
probable,  has  been  already  stated  (g  343). 


SENSE   OF   TASTE. 


867 


Fig.  202. 


Fig.  203. 


Capillary  network  of  fungiform  Various  forms  of  the  conical  compound  papillae  deprived  of  their 

papilla  of  the  Tongue.  epithelium;  a,  6,  and  especially  c,  are  the  best  marked,  and  were 

provided  with  the  stiffest  and  longest  epithelium ;  their  simple 
papillae  are  more  acuminated,  d  approaches  the  fungiform 
variety ;  e,  f  come  near  the  simple  papulae.— Magnified  20  diame- 
ters. 

they  are  readily  distinguished  from  the  filiform  papillae,  among  which  they  lie. 
The  filiform  papillae  (Figs.  203,  204,  B),  like  the  preceding,  contain  a  plexus 

Fig.  204. 


A  c 


A.  Vertical  section  near  the  middle  of  the  dorsal  surface  of  the  tongue :  a,  a.  Fungiform  papillae.    &.  Filiform 
papillae,  with  their  hair-like  processes,    c.  Similar  ones  deprived  of  their  epithelium. — Magnified  2  diameters. 

B.  Filiform  compound  papillae :  a.  Artery,    v.  Vein.    c.  Capillary  loops  of  the  secondary  papillae,    b.  Line 
of  basement-membrane,    d.  Secondary  papillae,  deprived  of  e,  e,  the  epithelium.   /.  Hair-like  processes  of  epi- 
thelium capping  the  simple  papillas.— Magnified  25  diameters,    g.  Separated  nucleated  particles  of  epithelium 
magnified  300  diameters. 

1,  2.  Hairs  found  on  the  surface  of  the  tongue.  3,  4,  5.  Ends  of  hair-like  epithelial  processes,  showing  varie- 
ties in  the  imbricated  arrangement  of  the  particles,  but  in  all  a  coalescence  of  the  particles  towards  the  point. 
5  incloses  a  soft  hair. — Magnified  160  diameters. 


868 


OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 


of  capillaries,  and  a  bundle  of  nerve-fibres  (Fig.  205),  both  terminating  in 
loops  which  enter  the  simple  papillae  that  clothe  the  surface  of  the  compound 
body ;  but,  instead  of  being  covered  with  a  thin  scaly  epithelium,  they  are  fur- 


Fig.  205. 


A.  Secondary  papilla  of  the  conical  class,  treated  with  acetic  acid  :  a.  Its  basement-membrane.    ft.  Its  nerve- 
tube  forming  a  loop.    c.  Its  curly  elastic  tissue.    The  epithelium  in  this  instance  is  not  abundant;  but  the 
vertical  arrangement  of  its  particles  over  the  apex  of  the  papilla  is  well  seen,  d,  and  illustrates  the  mode  of 
formation  of  the  hair-like  processes  described  in  the  text.— Magnified  160  diameters. 

B.  A  similar  papilla,  deprived  of  its  epithelium :  a.  Basement-membrane.    6.  Tubular  fibre,  probably  form- 
ing a  loop,  but  its  arch  not  clearly  seen,    c,  c.  Elastic  fibrous  tissue  at  its  base  and  in  its  interior.— Magnified 
320  diameters. 

c.  Nerves  of  a  compound  papilla  near  the  point  of  the  tongue,  in  which  their  loop-like  arrangement  is  dis- 
tinctly seen.— Magnified  160  diameters. 

nished  with  bundles  of  long  pointed  processes,  some  of  which  approach  hairs  in 
their  stiffness  and  structure.  These  are  immersed  in  the  mucus  of  the  mouth, 
and  may  be  moved  in  any  direction,  though  they  are  generally  inclined  back- 
wards.— The  simple  papillae  which  occur  in  an  isolated  manner,  with  those  which 
are  aggregated  in  the  circumvallate  and  fungiform  bodies,  doubtless  minister  to 
the  sense  of  Taste ;  but  there  seems  much  reason  to  coincide  in  the  opinion  of 
Messrs.  Todd  and  Bowman,  with  regard  to  the  different  office  of  the  filiform 
papillae.  "  The  comparative  thickness  of  their  protective  covering,  the  stiffness 
and  brush-like  arrangement  of  their  filamentary  productions,  their  greater  de- 
velopment in  that  portion  of  the  dorsum  of  the  tongue  which  is  chiefly  employed 
in  the  movements  of  mastication,  all  evince  the  subservience  of  these  papillae 
to  the  latter  function,  rather  than  to  that  of  taste ;  and  it  is  evident  that  their 
isolation  and  partial  mobility  on  one  another,  must  render  the  delicate  touch 
with  which  they  are  endowed,  more  available  in  directing  the  muscular  actions 
of  the  organ.  The  almost  manual  dexterity  of  the  organ,  in  dealing  with 
minute  particles  of  food,  is  probably  provided  for,  as  far  as  sensibility  conduces 
to  it,  in  the  structure  and  arrangement  of  these  papillae."  It  may  be  added, 


SENSE    OP   TASTE.  869 

that  the  filiform  papillae  of  Man  seem  to  be  the  rudimentary  forms  of  those 
horny  epithelial  processes  which  acquire  so  great  a  development  in  the  tongues 
of  the  Carnivora,  and  which  are  of  such  importance  in  the  abrasion  of  their  food. 
870.  The  simple  application  of  a  sapid  substance  to  the  gustative  surface  is 
usually  sufficient  to  excite  the  sensation ;  and  if  this  application  be  restricted 
to  one  particular  spot,  we  are  able  to  recognize  its  place  more  or  less  distinctly. 
In  this  respect,  then,  the  gustative  impression  resembles  the  tactile ;  for  whilst 
we  cannot,  by  our  own  consciousness,  distinguish  the  parts  of  the  retina  or  of 
the  auditory  apparatus  on  which  visual  or  auditory  impressions  are  made,  we  can 
make  this  distinction  in  regard  to  the  surface  which  is  supplied  by  the  nerves  of 
general  sense.  This  determination  is  most  precise  when  the  impression  is  made 
on  the  parts  of  the  tongue  of  which  the  gustative  sensibility  is  most  acute;  namely, 
the  apex,  sides,  and  posterior  part  of  the  dorsum  j  being  probably  aided,  however, 
near  the  tip,  by  the  acuteness  of  its  tactile  sensibility.  The  impressibility  of 
the  middle  portion  of  the  dorsum  is  greatly  inferior ;  but  still,  when  the  gustative 
sensation  has  been  excited  there,  it  is  referred  to  the  spot  on  which  the  sapid 
substance  was  laid.  The  contact  of  sapid  substances  much  more  readily  excites 
a  gustative  sensation,  when  it  is  made  to  press  upon  the  papillae,  or  is  moved 
over  them.  Thus  there  are  some  substances  whose  taste  is  not  perceived  when 
they  are  simply  applied  to  the  central  part  of  the  dorsum  of  the  tongue,  but  of 
whose  presence  we  are  at  once  rendered  cognizant  by  pressing  the  tongue  against 
the  roof  of  the  mouth.  The  full  flavor  of  a  sapid  substance,  again,  is  more 
readily  perceived  when  it  is  rubbed  on  any  part  of  the  tongue,  than  when  it  is 
simply  brought  in  contact  with  it,  or  pressed  against  it.  Even  when  liquids 
are  received  into  the  mouth,  their  taste  is  most  completely  descriminated  by 
causing  them  to  move  over  the  gustative  surface  :  thus  the  "  wine-taster"  takes 
a  small  quantity  of  the  liquor  into  his  mouth,  carries  it  rapidly  over  every  part 
of  its  lining  membrane,  and  then  ejects  it.  It  is  not  improbable  that  this  ex- 
altation of  the  usual  effects  is  simply  due  to  mechanical  causes ;  the  sapid  parti- 
cles being  brought  by  the  pressure  or  movement  into  more  rapid  and  complete 
operation  on  the  nerve-fibres,  than  they  would  be  if  simply  placed  in  contact 
with  the  papillae. — The  impressions  made  upon  our  consciousness  by  a  large 
proportion  of  sapid  substances  are  of  a  complex  kind  ;  being  in  part  derived  from 
their  odorous  emanations,  of  which  we  take  cognizance  through  the  organ  of 
Smell.  Of  this  any  one  may  convince  himself,  by  closing  the  nostrils,  and  in- 
spiring and  expiring  through  the  mouth  only,  whilst  holding  in  the  mouth,  or 
even  rubbing  between  the  tongue  and  the  palate,  some  aromatic  substance ;  for 
its  taste  is  then  scarcely  recognized,  although  it  is  immediately  perceived  when 
its  effluvia  are  drawn  into  the  nose.  It  is  well  known,  too,  that,  when  the 
sensibility  of  the  Schneiderian  membrane  is  blunted  by  inflammation  (as  in  an 
ordinary  cold  in  the  head),  the  power  of  distinguishing  flavors  is  very  much 
diminished.  In  fact,  some  Physiologists  are  of  opinion  that  all  our  knowledge 
of  the  flavor  of  sapid  substances  is  received  through  the  Smell ;  but  this,  as 
already  shown,  would  not  be  a  correct  statement ;  and  there  are  cases  on  record 
in  which  the  sense  of  Smell  has  been  entirely  lost,  without  any  impairment  of 
the  true  sense  of  Taste.1 

1  An  interesting  case  of  this  kind,  occurring  in  a  Negro  who  had  gradually  lost  the 
characteristic  hue  of  his  skin,  and  had  acquired  the  fair  complexion  of  a  European,  has 
lately  been  put  on  record  by  Dr.  J.  C.  Hutchison. — The  Olfactory  nerve  seemed  to  be  en- 
tirely paralyzed,  whilst  the  branches  of  the  5th  Pair  retained  their  integrity ;  so  that, 
whilst  the  proper  sense  of  Smell  was  entirely  lost,  a  pungent  burning  sensation  was  excited 
by  irritating  vapors,  and  the  application  of  snuif  induced  sneezing.  Notwithstanding  this 
deficiency,  the  sense  of  Taste,  properly  so  called,  did  not  seem  to  be  impaired ;  for  substances 
which  neither  possessed  odor  nor  pungency  could  be  readily  discriminated,  even  though 
their  tastes  were  not  widely  different.  (See  "  Amer.  Journ.  of  Med.  Sci."  Jan.  1852.) 


870     OF  SENSATION,  AND  THE  ORGANS  OP  THE  SENSES. 

871.  Taken  in  its  ordinary  compound  acceptation,  the  sense  of  Taste  has  for 
its  object  to  direct  us  in  the  choice  of  food,  and  to  excite  the  flow  of  mucus  and 
saliva,  which  are  destined  to  aid  in  the  preparation  of  the  food  for  Digestion. 
Among  the  lower  Animals,  the  instinctive  perceptions  connected  with  this  sense 
are  much  more  remarkable  than  our  own;  thus  an  omnivorous  Monkey  will  seldom 
touch  fruits  of  a  poisonous  character,  although  their  taste  may  be  agreeable ;  and 
animals,  whose  diet  is  restricted  to  some  one  kind  of  food,  will  decidedly  reject 
all  others.  As  a  general  rule,  it  may  be  stated  that  substances  of  which  the 
taste  is  agreeable  to  us,  are  useful  in  our  nutrition,  and  vice  versa  ;*  but  there 
are  many  signal  exceptions  to  this. — Like  other  senses,  that  of  Taste  is  capable 
of  being  rendered  more  acute  by  education ;  and  this  on  the  principles  already 
laid  down  in  regard  to  Touch.  The  experienced  wine-taster  can  distinguish 
differences  in  age,  purity,  place  of  growth,  &c.,  between  liquors  that  to  ordinary 
judgments  are  alike ;  and  the  epicure  can  give  an  exact  determination  of  the 
spices  that  are  combined  in  a  particular  sauce,  or  of  the  manner  in  which  the 
animal,  on  whose  flesh  he  is  feeding,  was  killed.  As  in  the  case  of  other  senses, 
moreover,  impressions  made  upon  the  sensory  surface  remain  there  for  a  certain 
period ;  and  this  period  is  for  the  most  part  longer  than  that  which  is  required 
for  the  departure  of  the  impressions  made  upon  the  eye,  the  ear,  or  the  organ 
of  smell.  Every  one  knows  how  long  the  taste  of  some  powerful  substances 
remains  in  the  mouth ;  and  even  of  those  which  make  less  decided  impressions, 
the  sensations  remain  to  such  a  degree  that  it  is  difficult  to  compare  them  at 
short  intervals.  Hence  if  a  person  be  blindfolded,  and  be  made  to  taste  sub- 
stances of  distinct,  but  not  widely  different  flavors  (such  as  various  kinds  of  wine 
or  of  spirituous  liquors),  one  after  another  in  rapid  succession,  he  soon  loses  the 
power  of  discriminating  between  them.  In  the  same  manner,  the  difficulty  of 
administering  very  disagreeable  medicines  may  be  sometimes  got  over,  by  either 
previously  giving  a  powerful  aromatic,  or  by  combining  the  aromatic  with  the 
medicine ;  its  strong  impression  in  both  cases  preventing  the  unpleasant  taste 
from  exciting  nausea. 

1  It  is  justly  remarked  by  Dr.  Holland  ("  Medical  Notes  and  Reflections,"  p.  85),  that 
— "In  the  majority  of  instances  of  actual  illness,  provided  the  real  feelings  of  the  patient 
can  be  safely  ascertained,  his  desires  as  to  food  and  drink  may  be  safely  complied  with. 
But  undoubtedly  much  care  is  needful  that  we  be  not  deceived  as  to  the  state  of  the  appe- 
tites, by  what  is  merely  habit  or  wrong  impression  on  the  part  of  the  patient,  or  the  effect 
of  the  solicitation  of  others.  This  class  of  sensations  is  more  nurtured  out  of  the  course 
of  nature,  than  are  those  which  relate  to  the  temperature  of  the  body.  The  mind  becomes 
much  more  deeply  engaged  with  them  ;  and  though  in  acute  illness  they  are  generally 
submitted  again  to  the  natural  law,  there  are  many  lesser  cases  where  enough  remains  of 
the  leaven  of  habit  to  render  every  precaution  needful.  With  such  precautions,  however, 
which  every  physician  who  can  take  schooling  from  experience  will  employ,  the  stomach 
of  the  patient  becomes  a  valuable  guide ;  whether  it  dictate  abstinence  from  a  recurrence 
of  food  ;  whether  much  or  little  in  quantity  ;  whether  what  is  solid  or  liquid  ;  whether 
much  drink  or  little  ;  whether  things  warm  or  cold ;  whether  sweet,  acid,  or  saline ;  whether 
bland  or  stimulating  to  the  taste."  Further,  Dr.  Holland  remarks :  "  It  is  not  wholly 
paradoxical  to  say  that  we  are  authorized  to  give  greatest  heed  to  the  stomach  when  it 
suggests  some  seeming  extravagance  of  diet.  It  may  be  that  this  is  a  mere  depravation 
of  the  sense  of  taste  ;  but  frequently  it  expresses  an  actual  need  of  the  stomach,  either  in 
aid  of  its  own  functions,  or  indirectly  (under  the  mysterious  law  just  referred  to)  for  the 
effecting  of  changes  in  the  whole  mass  of  blood.  It  is  a  good  practical  rule  in  such  cases 
to  withhold  assent,  till  we  find  after  a  certain  lapse  of  time  that  the  same  desire  continues 
or  strongly  recurs ;  in  which  case  it  may  generally  be  taken  as  the  index  of  the  fitness  of 
the  thing  desired  for  the  actual  state  of  the  organs.  In  the  early  stage  of  recovery  from 
long  gastric  fevers,  I  recollect  many  curious  instances  of  such  contrariety  to  all  rule  being 
acquiesced  in,  with  manifest  good  to  the  patient.  Dietetics  must  become  a  much  more 
exact  branch  of  knowledge,  before  we  can  be  justified  in  opposing  its  maxims  to  the  natural 
and  repeated  suggestions  of  the  stomach,  in  the  state  either  of  health  or  disease." 


SENSE   OF    SMELL.  871 


4. — Sense  of  Smell. 

872.  Of  the  nature  of  Odorous  emanations,  the  Natural  Philosopher  is  so 
completely  ignorant,  that  the  Physiologist  cannot  be  expected  to  give  a  definite 
account  of  the  mode  in  which  they  produce  sensory  impressions.  Although  it 
may  be  surmised  that  they  consist  of  particles  of  extreme  minuteness,  dissolved 
as  it  were  in  the  air,  and  although  this  idea  seems  to  derive  confirmation  from 
the  fact  that  most  odorous  substances  are  volatile,  and  vice  versd — yet  the  most 
delicate  experiments  have  failed  to  discover  any  diminution  in  weight,  in  certain 

Fig.  206. 


Distribution  of  the  Olfactory  Nerve  on  the  Septum  Nasi.  The  nares  have  been  divided  by  a  longitudinal 
section  made  immediately  to  the  left  of  the  septum,  the  right  nares  being  preserved  entire. — 1.  The  frontal 
sinus.  2.  The  nasal  bone.  3.  The  crista  galli  process  of  the  ethmoid  bone.  4.  The  sphenoidal  sinus  of  the 
leftside.  5.  The  sella  turcica.  6.  The  basilar  process  of  the  sphenoid  and  occipital  bones.  7.  The  posterior 
opening  of  the  right  nares.  8.  The  opening  of  the  Eustachian  tube  in  the  upper  part  of  the  pharynx.  9.  The 
soft  palate,  divided  through  its  middle.  10.  Cut  surface  of  the  hard  palate,  a.  The  olfactory  peduncle, 
fe.  Its  three  roots  of  origin,  c.  Olfactory  ganglion,  from  which  the  filaments  proceed  that  spread  out  in  the 
substance  of  the  pituitary  membrane,  d.  The  nasal  nerve,  a  branch  of  the  ophthalmic  nerve,  descending  into 
the  left  nares  from  the  anterior  foramen  of  the  cribriform  plate,  and  dividing  into  its  external  and  internal 
branch,  e.  The  naso-palatine  nerve,  a  branch  of  the  spheno-palatine  ganglion  distributing  twigs  to  the  mucous  ' 
membrane  of  the  septum  nasi  in  its  course  to  (/)  the  anterior  palatine  foramen,  where  it  forms  a  small  gangli- 
form  swelling  (Cloquet's  ganglion)  by  its  union  with  its  fellow  of  the  opposite  side.  g.  Branches  of  the  naso- 
palatine  nerve  to  the  palate,  h.  Posterior  palatine  nerves,  t,  i.  The  septum  nasL 

I 

substances  (as  musk)  that  have  been  impregnating  with  their  effluvia  a  large 
quantity  of  air  for  several  years ;  and  there  are  some  volatile  fluids,  such  as 
water,  which  are  entirely  inodorous.  The  true  Olfactory  nerves  pass  down  from 
the  Olfactory  Ganglion  (§  729)  in  the  form  of  very  numerous  minute  threads, 
which  form  a  plexus  upon  the  surface  of  the  Schneiderian  or  pituitary  membrane 
(Fig.  206).  The  filaments  composing  this  plexus  are  described  by  Messrs.  Todd 
and  Bowman1  as  differing  widely  from  those  of  the  ordinary  cephalic  nerves  in 
structure;  they  contain  no  white  substance  of  Schwann,  are  nucleated  and  finely 
granular  in  texture,  and  altogether  bear  a  close  resemblance  to  the  gelatinous 
form  of  nerve-fibres  (Fig.  207).  It  has  been  hitherto  found  impossible  to  trace 
the  ultimate  distribution  of  these  fibres  in  the  olfactory  membrane,  owing  to 

1  "Physiological  Anatomy,"  p.  397,  Am.  Ed. 


872 


OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES, 


Fig.  207. 


Olfactory  filaments  of  the  Dog:  a.    In  water. 
b.  In  acetic  acid.— Magnified  250  diameters. 


their  want  of  the  characteristic  white  substance,  and  the  absence  of  distinction 

between  the  nuclei  of  the  minuter  fibres 
and  those  of  the  nucleated  tissues  through 
which  they  pass.  It  would  appear  that 
every  part  of  the  Schneiderian  membrane 
is  not  equally  endowed  with  the  faculty  of 
distinguishing  odors,  which  is  a  very  dif- 
ferent power  from  that  of  becoming  sensi- 
ble of  irritation  from  them.  The  distribu- 
tion of  the  Olfactory  nerves  seems  limited 
to  the  membrane  covering  the  superior 
three-fourths  of  the  septum  of  the  nose, 
the  superior  turbinated  bone  and  the  upper 
half  of  the  middle  turbinated  bone,  and  the 
upper  wall  of  the  nasal  cavities  beneath 
the  cribriform  plate  of  the  ethmoid  bone ; 
all  which  surface  is  covered  (as  Messrs. 
Todd  and  Bowman  have  pointed  out)  with 
a  tessellated  epithelium  of  a  rich  sepia- 
brdwn  hue.  The  remainder  of  the  nasal 
surface  is  supplied  by  the  5th  Pair  only;  and  hence  it  is  that  we  cannot  dis- 
tinguish faint  odors,  unless,  by  a  peculiar  inspiratory  effort,  we  draw  the  air 
charged  with  them  to  the  upper  part  of  the  nose.  In  animals  living  in  the 
air,  it  is  a  necessary  condition  of  the  exercise  of  the  sense  of  Smell  that  the 
odorous  matter  should  be  transmitted  by  a  respiratory  current  through  the 
nostrils;  and  that  the  membrane  lining  these  should  be  in  a  moist  state. 
Hence,  by  breathing  through  the  mouth,  we  may  avoid  being  affected  by 
odors  even  of  the  strongest  and  most  disagreeable  kind ;  and  in  the  first  stage 
of  a  catarrh,  when  the  ordinary  mucous  secretion  is  suspended,  the  sense  of 
Smell  is  blunted  from  this  cause,  as  it  afterwards  is  from  the  excess  in  the 
quantity  of  the  fluid,  which  prevents  the  odoriferous  effluvia  from  coming 
into  immediate  relation  with  the  sensory  extremities  of  the  nerves.  Hence 
we  may  easily  comprehend  how  section  of  the  5th  Pair,  which  exerts  a  con- 
siderable influence  over  the  secretions,  will  greatly  diminish  the  acuteness  of 
this  sense,  and  will  have  the  further  effect  of  preventing  the  reception  of  any 
impressions  of  irritation  from  acrid  vapors,  which  are  entirely  different  in  their 
character  from  true  odorous  impressions,  and  are  not  transmitted  through  the 
Olfactory  nerve  (§  739).  The  nasal  passages  may  indeed  be  considered  as 
having,  in  the  air-breathing  Vertebra ta,  two  distinct  offices ;  they  constitute  the 
organ  of  Smell,  through  the  distribution  of  the  olfactory  nerve  upon  a  part  of 
their  surface  ;  but  they  also  constitute  the  portals  of  the  respiratory  organs, 
having  for  their  office  to  take  cognizance  of  the  aeriform  matter  which  enters 
them,  and  to  give  warning  of  that  which  would  be  injurious;  this  latter  function 
is  performed  by  the  5th  Pair,  as  by  the  Pneumogastric  in  the  glottis.  It  is 
through  this  nerve  that  the  act  of  Sneezing  is  excitable;  the  evident  purpose  of 
which  is  the  ejection  of  a  strong  blast  of  air  through  the  nasal  passages,  in  such 
a  manner  as  to  drive  out  any  offending  matter  they  may  contain. 

873.  The  importance  of  the  sense  of  Smell  among  many  of  the  lower  Ani- 
mals, in  guiding  them  to  their  food,  or  in  giving  them  warning  of  danger,  and 
also  in  exciting  the  sexual  feelings,  is  well  known.  To  Man  its  utility  is  com- 
paratively small  under  ordinary  circumstances  ;  but  it  may  be  greatly  increased 
when  other  senses  are  deficient.  Thus,  in  the  well-known  case  of  James  Mit- 
chell, who  was  deaf,  blind,  and  dumb  from  his  birth,  it  was  the  principal  means 
of  distinguishing  persons,  and  enable  him  at  once  to  perceive  the  entrance  of  a 
stranger.  It  is  recorded  that  a  blind  gentleman,  who  had  an  antipathy  to  cats, 


SENSE   OP   VISION.  873 

was  possessed  of  a  sensibility  so  acute  in  this  respect,  that  he  perceived  the 
proximity  of  one  that  had  been  accidentally  shut  up  in  a  closet  adjoining  his 
room.  Among  Savage  tribes,  whose  senses  are  more  cultivated  than  those  of 
civilized  nations,  more  direct  use  being  made  of  the  powers  of  observation,  the 
scent  is  almost  as  acute  as  in  the  lower  Mammalia ;  it  is  asserted  by  Humboldt, 
that  the  Peruvian  Indians  in  the  middle  of  the  night  can  thus  distinguish  the 
different  races,  whether  European,  American  Indian,  or  Negro.1 — The  agreeable 
or  disagreeable  character  assigned  to  particular  odors  is  by  no  means  constant 
amongst  different  individuals.  Many  of  the  lower  Animals  pass  their  whole 
lives  in  the  midst  of  odors,  which  are  to  Man  (in  his  civilized  condition  at  least) 
in  the  highest  degree  revolting ;  and  will  even  refuse  to  touch  food  until  it  is  far 
advanced  in  putridity.  It  more  frequently  happens  in  regard  to  odors  and  savors, 
than  with  respect  to  other  sensory  impressions,  that  habit  makes  that  agreeable, 
and  even  strongly  relished,  which  was  at  first  avoided ;  the  taste  of  the  epicure 
for  game  that  has  acquired  ihefumet — for  olives — for  assafoetida,  &c.,  are  in- 
stances of  this.  As  to  the  length  of  time  during  which  impressions  made  upon 
the  organ  of  smell  remain  upon  it,  no  certain  knowledge  can  be  obtained.  It 
is  difficult  to  say  when  the  effluvia  have  been  completely  removed  from  the  nasal 
passages,  since  it  is  not  unlikely  that  the  odorous  particles  (supposing  such  to 
exist)  are  absorbed  or  dissolved  by  the  mucous  secretion ;  it  is  probably  in  this 
manner  that  we  may  account  for  the  fact,  well  known  to  every  medical  man, 
that  the  cadaverous  odor  is  frequently  experienced  for  days  after  a  post-mortem 
examination.3 

5. — Sense  of  Vision. 

874.  The  objects  of  this  sense  are  bodies,  which  are  either  in  themselves 
luminous,  or  which  become  so  by  reflecting  the  light  that  proceeds  from  others. 
Whether  their  light  is  transmitted  by  the  actual  emission  of  luminous  particles, 
or  by  the  propagation  of  undulations  analogous  to  those  of  sound,  is  a  question 
that  has  been  long  keenly  debated  amongst  Natural  Philosophers ;  but  it  is  of 
little  consequence  to  the  Physiologist  which  is  the  true  solution,  since  it  is  only 
with  the  laws  according  to  which  the  transmission  takes  place  that  he  is  con- 
cerned.    These  laws  it  may  be  desirable  here  briefly  to  recapitulate. 

875.  Every  point  of  a  luminous  body  sends  off  a  number  of  rays,  which 
diverge  in  every  direction,  so  as  to  form  a  cone,  of  which  the  luminous  point  is 
the  apex.     So  long  as  these  rays  pass  through  a  medium  of  the  same  density, 
they  proceed  in  straight  lines ;  but,  if  they  enter  a  medium  of  different  density, 
they  are  refracted  or  bent — towards  the  perpendicular  to  the  surface  at  the 
point  at  which  they  enter,  if  they  pass  from  a  rarer  into  a  denser  medium,  and 
from  the  perpendicular,  when  they  pass  from  a  denser  medium  into  a  rarer.    It 
is  easily  shown  to  be  a  result  of  this  law,  that,  when  parallel  rays  passing  through 
air  fall  upon  a  convex  surface  of  glass,  they  will  be  made  to  converge ;  so  as  to 
meet  at  the  opposite  extremity  of  the  diameter  of  the  circle,  of  which  the  curve 
forms  part.     If,  instead  of  continuing  in  the  glass,  they  pass  out  again,  through 
a  second  convex  surface,  of  which  the  direction  is  the  reverse  of  the  first,  they 
will  be  made  to  converge  still  more,  so  as  to  meet  in  the  centre  of  curvature. 
Rays  which  are  not  parallel,  but  which  are  diverging  from  a  focus,  are  likewise 
made  to  converge  to  a  point  or  focus ;  but  this  point  will  be  more  distant  from 
the  lens,  in  proportion  as  the  object  is  nearer  to  it,  and  the  angle  of  divergence 

1  The  Author  has  been  assured  by  a  competent  witness,  that  a  youth  in  the  state  of, 
Hypnotism  had  his  sense  of  Smell  so  remarkably  heightened,  as  to  be  able  to  assign  (with- 
out the  least  hesitation)  a  glove  placed  in  his  hand,  to  its  right  owner — in  the  midst  of 
about  thirty  persons,  the  boy  himself  being  blindfolded. 

2  This  may  partly  be  attributed  also  to  the  effluvia  adhering  to  the  dress.     It  has  been 
remarked  that  dark  cloths  retain  these  more  strongly  than  light. 


874     OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 

consequently  greater.  The  rays  diverging  from  the  several  points  of  a  luminous 
object  are  thus  brought  to  a  corresponding  focus ;  and  the  places  of  all  these 
foci  hold  exactly  the  same  relation  to  each  other,  with  that  of  the  points  from 
which  the  rays  diverged;  so  that  a  perfect  image  of  the  object  is  formed 
upon  a  screen  held  in  the  focus  of  the  lens.  This  image,  however,  will  be  in- 
verted ;  and  its  size,  in  proportion  to  that  of  the  object,  will  depend  upon  their 
respective  distances  from  the  lens.  If  their  distances  be  the  same,  their  size 
will  also  be  the  same;  if  the  object  be  distant,  and  the  image  near,  the  latter 
will  be  much  the  smaller ;  and  vice  versa. 

876.  There  are  two  circumstances,  however,  which  interfere  with  the  perfec- 
tion of  an  image  thus  formed  by  a  convex  lens.     The  one  is,  that  if  the  lens 
constitute  a  large  part  of  the  sphere  from  which  it  is  taken,  the  rays  which  fall 
near  its  margin  are  not  brought  to  a  focus  at  the  same  point  with  those  which 
pass  through  its  centre,  but  at  a  point  nearer  the  lens.     This  difference,  which 
must  obviously  interfere  greatly  with  the  distinctness  of  the  image,  is  termed 
Spherical  Aberration  ;  it  may  be  corrected  by  the  combination  of  two  or  more 
lenses,  of  which  the  curvatures  are  calculated  to  balance  one  another  in  such  a 
manner,  that  all  the  rays  shall  be  brought  to  the  same  focus ;  or  by  diminishing 
the  aperture  of  the  lens  by  means  of  a  stop  or  diaphragm,  in  such  a  manner 
that  only  the  central  part  of  it  shall  be  used.     The  latter  of  these  methods  is 
the  one  employed  where  the  diminution  in  the  amount  of  light  transmitted  is 
not  attended  with  inconvenience.     The  nearer  the  object  is  to  the  lens  (and  the 
greater,  therefore,  the  angle  of  divergence  of  its  rays),  the  greater  will  be  the 
spherical  aberration,  and  the  more  must  the  aperture  of  the  diaphragm  be  con- 
tracted in  order  to  counteract  it. — The  other  circumstance  that  interferes  with 
the  distinctness  of  the  image  is  the  unequal  refrangibility  of  the  differently 
colored  rays,  which  together  make  up  white  or  colorless  light ;  the  violet  being 
more  bent  from  their  course  than  the  blue,  the  blue  more  than  the  yellow,  and 
the  yellow  more  than  the  red  ;  the  consequence  of  which  will  be,  that  the  violet 
rays  are  brought  to  a  focus  much  nearer  to  the  lens  than  the  blue,  and  the  blue 
nearer  than  the  red.     If  a  screen  be  held  to  receive  the  image  in  the  focus  of 
any  of  the  rays,  the  others  will  make  themselves  apparent  as  fringes  round  its 
margin.     This  difference  is  termed  Chromatic  Aberration.     It  is  corrected  in 
practice,  by  combining  together  lenses  of  different   substances,  of  which   the 
dispersive  power  (that  is,  the  power  of  separating  the  colored  rays)  differs  con- 
siderably.    This  is  the  case  with  flint  and  crown  glass  for  instance — the  dis- 
persive power  of  the  former  being  much  greater  than  that  of  the  latter,  whilst 
its  refractive  power  is  nearly  the  same  :  so  that,  if  a  convex  lens  of  crown 
glass  be  united  with  a  concave  of  flint,  whose  curvature  is  much  less,  the  dis- 
persion of  the  rays  effected  by  the  former  will  be  entirely  counteracted  by  the 
latter,  which  diminishes  in  part  only  its  refractive  power. 

877.  The  Eye  may  be  regarded  as  an  optical  instrument  of  great  perfection, 
adapted  to  produce,  on  the  expanded  surface  of  the  Optic  nerve,  a  complete 
image  or  picture  of  luminous  objects  brought  before  it ;  in  which  the  forms, 
colors,  lights  and  shades,  &c.  of  the  object  are  all  accurately  represented.     By 
the  different  refractive  powers  of  the  transparent  media  through  which  the  rays 
of  light  pass,  and  by  the  curvatures  given  to  their  respective  surfaces,  both  the 
Spherical  and  Chromatic  aberrations  are  corrected  in  a  degree  sufficient  for  all 
practical  purposes ;  so  that,  in  a  well-formed  eye,  the  picture  is  quite  free  from 
haziness  and  from  false  colors.     The  power  by  which  it  adapts  itself  to  varia- 
tions in  the  distance  of  the  object,  so  as  to  form  a  distinct  image  of  it,  whether 
it  be  six  inches,  six  yards,  or  six  miles  off,  is  extremely  remarkable,  and  cannot 
be  regarded  as  hitherto  completely  explained.     It  is  obvious  that,  if  we  fix 
upon  any  distance,  as  that  for  which  the  eye  is  naturally  adjusted  (say  12  or  14 
inches,  the  distance  at  which  we  ordinarily  read),  the  rays  proceeding  from  an 


SENSE   OP  VISION.  875 

object  placed  Nearer  to  the  eye  than  this  would  not  be  brought  to  a  focus  upon 
the  retina,  but  would  converge  towards  a  point  behind  it ;  whilst,  on  the  con- 
trary, the  rays  from  an  object  at  a  greater  distance  would  meet  before  they 

Fig.  208. 


A  longitudinal  section  of  the  globe  of  the  Eye :  1,  the  sclerotic,  thicker  behind  than  in  front;  2,  the  cornea, 
received  within  the  anterior  margin  of  the  sclerotic,  and  connected  with  it  by  means  of  a  bevelled  edge ;  3,  the 
choroid  connected  anteriorly  with  (4)  the  ciliary  ligament,  and  (5)  the  ciliary  processes ;  6,  the  iris ;  7,  the 
pupil ;  8,  the  third  layer  of  the  eye,  the  retina  terminating  anteriorly  by  an  abrupt  border  at  the  commence- 
ment of  the  ciliary  processes ;  9,  the  canal  of  Petit,  which  encircles  the  lens  (12);  the  thin  layer  in  front  of 
this  canal  is  the  zonula  ciliaris,  a  prolongation  of  the  vascular  layer  of  the  retina  to  the  lens  ;  10,  the  anterior 
chamber  of  the  eye,  containing  the  aqueous  humor ;  the  lining  membrane  by  which  the  humor  is  secreted  is 
represented  in  the  diagram ;  11,  the  posterior ;  12,  the  lens  more  convex  behind  than  before,  and  inclosed  in 
its  proper  capsule;  13,  the  vitreous  humor  inclosed  in  the  hyaloid  membrane,  and  in  cells  formed  in  its  inte- 
rior by  that  membrane :  14,  a  tubular  sheath  of  the  hyaloid  membrane,  which  serves  for  the  passage  of  the 
artery  of  the  capsule  of  the  lens;  15,  neurilemma  of  the  optic  nerve;  16,  the  arteria  centralis  retinae,  imbed- 
ded in  its  centre. 

reached  the  retina,  and  would  have  again  diverged  from  each  other  when  they 
impinge  upon  it ;  so  that,  in  either  case,  vision  would  be  indistinct.  Now,  two 
methods  of  adaptation  suggest  themselves  to  the  Optician.  Either  he  may 
vary  the  distance  between  the  refracting  surface  and  the  screen  on  which  the 
image  is  formed,  in  such  a  manner  that  the  latter  shall  always  be  in  the  focus 
of  the  converging  rays ;  or  the  distance  of  the  screen  remaining  the  same,  he 
may  vary  the  convexity  of  his  lens  in  such  a  manner  as  to  adapt  it  to  the  dis- 
tance of  the  object.  The  mode  in  which  this  adaptation  is  effected  in  the  Hu- 
man Eye  has  not  yet  been  clearly  made  out ;  and  many  hypotheses  have  been 
put  forward  respecting  it.  According  to  the  calculations  of  Olbers,  based  on 
the  ascertained  refractive  powers  of  the  media  of  the  eye,  the  difference  be- 
tween the  focal  distances  of  the  images  of  two  objects,  the  one  so  far  off  that 
its  rays  are  parallel,  and  the  other  at  the  distance  of  only  four  inches  from  the 
eye,  is  about  0.143,  or  one-seventh  of  an  inch ;  but,  as  the  usual  range  of  dis- 
tinct vision  does  not  extend  to  objects  brought  within  six  or  seven  inches,  the 
amount  of  change  required  in  the  relative  places  of  the  refracting  bodies  and 
the  retina  would  not  ordinarily  exceed  a  line.  It  has  been  thought  that  this 
change  might  be  produced  by  an  alteration  in  the  convexity  of  the  cornea,  or 
by  an  elongation  of  the  globe  of  the  eye  generally,  or  by  both  methods  in  com- 
bination j  which  alterations,  it  was  supposed,  might  be  effected  by  the  action  of 
the  muscles  of  the  eyeball.  But  no  such  changes  have  been  detected  by  the 
most  careful  measurement ;  and  it  cannot  be  shown  how  any  contractile  action 
of  the  muscles  of  the  eyeball  could  produce  an  elongation  of  the  eye,  since 
their  tendency  would  be  (when  acting  altogether)  to  draw  it  backwards  into  its 
socket,  or,  this  being  prevented  by  the  fascia  and  cushion  of  fat  against  which 


876 


OP  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 


Fig.  209. 


its  posterior  side  rests,  to  flatten  the  globe  against  this,  rather  than  to  increase 
its  projection.  There  is  much  more  ground  for  the  belief,  however,  that  a 
change  of  place  is  effected  in  the  crystalline  lens,  by  the  action  of  the  ciliary 
muscle,  and  the  erectile  tissue  of  the  ciliary  processes  ;  for,  although  no  such 
change  can  be  demonstrated  by  observation,  yet  it  can  be  shown  that  the  con- 
traction of  the  ciliary  muscle  (Fig.  209)  would  tend  to  draw  the  lens  forwards  ; 
and  the  fact  that  this  muscle  is  peculiarly  powerful 
in  the  predaceous  birds,  which  are  distinguished  for 
their  great  range  of  vision,  and  which  have,  in  their 
circle  of  osseous  sclerotic  plates,  an  unusually  firm 
point  of  attachment  for  it,  is  a  strong  argument  in  fa- 
vor of  this  doctrine.1  Further,  the  almost  entire  loss 
of  the  power  of  adapting  the  eye  to  distances,  which 
is  experienced  after  the  removal  of  the  Crystalline 
lens  in  the  operation  for  Cataract,  is  a  marked  indica- 
^on  tnat  some  change  in  the  place  or  figure  of  this 
body  is  the  principal  means  whereby  the  ordinary 
adaptation  is  effected  ;  and  although  it  has  been  sug- 
gested that  an  alteration  in  the  figure  of  the  lens 

Diagram  to  show  the  position  might  participate  in  the  result,  yet  no  means  can  be 
and  action  of  the  Ciliary  Muscle  :   pointed  out  as  competent  to  produce  it  ;  so  that,  as  far 

^    WQ    cafl       fc    pregent  judge     a    change  jn    the       j 
»    .,       ,  .     \  i  <•      -,        •  i          " 

«  ™  len.s  ,1S  the  8<>le  means  of  adapting  the  eye  to 

iary  ligament,  and  point  from  distinct  vision  at  varying  distances.  —  It  is  certain 
which  the  ciliary  muscle  radiates-  that  the  condition  of  repose  is  that  of  vision  for  dis- 
e.  iris.  n.  Lens,  connected  with  tant  0bjectS)  no  fatigue  being  experienced  from  the 

the  ciliary  processes  by  the  ante-  }  d    direction  of  the    eye  to    these;    whilst    the 

rior  wall  of  the  canal  of  Petit,  the     "        .     fe  _     .         .         ,          J  >       .  . 

situation  of  which  is  marked  by  employment  of  the  visual  power  upon  near  objects  for 

the  *.—  Magnified  3  diameters.         some  time  is  accompanied  with  a  sense  of  effort,  and 

is  followed  by  fatigue.     The  movement  which  effects 

the  change  of  place  of  the  crystalline  lens  is  performed  in  obedience  to  Volition, 
and  is  guided  by  sensation  ;  yet  we  are  not  conscious  of  performing  it,  all  that 
we  will  being  the  result  ;  and  thus  we  have  another  apposite  illustration  of  the 
really  automatic  nature  of  what  are  termed  voluntary  movements  generally  (757). 
878.  When  both  eyes  are  fixed  upon  an  object,  their  axes  converge  so  as  to 
meet  in  it  ;  and  the  degree  of  convergence  is  of  course  altered  by  variations  in 
the  distance  of  the  object  ;  since,  when  the  object  is  very  remote,  the  optic  axes 
are  virtually  parallel,  whilst  its  approach  causes  them  to  incline  towards  each 
other,  and  this  the  more  rapidly  as  the  object  is  brought  nearer,  the  increase 
being  the  greatest  when  it  has  arrived  within  the  ordinary  distance  of  distinct 
vision.  Here,  again,  we  have  an  example  of  the  automatic  nature  of  voluntary 
actions  ;  for  the  convergence  of  the  eyes  that  may  be  produced  by  such  a  gradual 
approximation  of  an  object  on  which  the  eyes  are  kept  fixed  by  an  effort  of  the 
Will,  far  exceeds  that  which  most  individuals  can  induce  by  an  effort  made  directly 
for  the  purpose  ;  and  if,  when  an  object  has  thus  been  gradually  approximated 
to  within  a  few  inches  of  the  nose,  the  effort  be  intermitted  and  the  optic  axes 
be  allowed  to  regain  their  parallelism,  they  can  seldom  be  brought  to  converge 
again  upon  it,  without  repeating  the  whole  process.  —  It  has  been  thought,  from 
the  close  accordance  between  the  changes  required  for  the  adaptation  of  the  eyes 
to  distinct  vision  at  different  distances,  and  the  alterations  in  the  direction  of 
the  optic  axes  which  are  required  to  bring  the  two  eyes  to  bear  upon  objects  at 

'  See,  on  this  subject,  Messrs.  Todd  and  Bowman's  "  Physiological  Anatomy,"  p.  412, 
Am.  Ed.  ;  and  Dr.  Clay  Wallace  on  "The  Adjustment  of  the  Eye  to  Distances,"  New  York, 
1851. 


-a   Sclerotic^.  Cornea    c.  Cho- 
roid,  separated  a  little  from  the 

sclerotic,  d.  situation  of  the  di- 


SENSE   OF   VISION.  877 

varying  degrees  of  proximity  or  remoteness,  that  the  former  of  these  movements 
is  in  some  degree  dependent  upon  the  latter,  or,  at  any  rate,  that  the  two  pro- 
ceed from  a  common  motor  impulse.  But  that  the  convergence  of  the  axes  is 
not  itself  in  any  way  the  occasion  of  the  alteration  of  the  focus  of  the  eye,  is 
shown  by  these  two  facts ;  first,  that  the  adaptation  is  as  perfect  in  a  person 
who  only  possesses  or  uses  one  eye,  as  it  is  when  both  are  .employed;  and  second, 
that  some  persons  possess  the  power  of  altering  the  focus  of  the  eye  by  an  effort 
of  the  will,  whilst  the  convergence  remains  the  same. — In  regard  to  the  adap- 
tation of  the  eyes  to  varying  distances,  it  is  further  to  be  remarked,  that,  when 
an  object  is  being  viewed  as  near  to  the  eye  as  it  can  be  distinctly  seen,  the 
pupil  contracts  in  a  considerable  degree.  The  purpose  of  this  change  is  evidently 
to  exclude  the  outer  rays  of  the  cone  or  pencil,  which,  from  the  large  angle  of 
their  divergence,  would  fall  so  obliquely  on  the  convex  surface  of  the  eye  as  to 
be  much  affected  by  the  spherical  aberration  ;  and  thus  to  allow  the  central  rays 
only  to  enter  the  eye,  so  as  to  preserve  the  clearness  of  the  image.  The  channel 
through  which  it  is  effected  is  evidently  the  same  as  that  by  which  the  converg- 
ence of  the  eyes  is  produced — namely,  the  inferior  branch  of  the  3d  Pair  of 
nerves ;  to  the  action  of  which,  the  sensations  received  through  the  retina  form 
the  immediate  stimulus,  in  the  same  manner  as  they  do  to  the  ordinary  varia- 
tion in  the  diameter  of  the  pupil  under  the  influence  of  light ;  but  the  volun- 
tary determination  to  fix  the  vision  upon  the  object  is  the  original  source  of  the 
action. 

879.  The  ordinary  forms  of  defective  vision,  which  are  known  under  the 
names  of  Myopia  and  Presbyopia,  or  "short-sightedness"  and  "  long-sighted- 
ness," are  entirely  attributable  to  defects  in  the  optical  adaptation  of  the  eye. 
In  the  former,  its  refractive  power  is  too  great ;  the  rays  from  objects  at  the 
usual  distance  are  consequently  brought  too  soon  to  a  focus,  so  as  to  cross  one 
another  and  diverge  before  they  fall  upon  the  retina ;  whilst  the  eye  is  adapted 
to  bring  to  their  proper  focus  on  the  retina  only  those  rays  which  were  pre- 
viously diverging  at  a  large  angle,  from  an  object  in  its  near  proximity.  Hence 
a  "short-sighted"  person,  whose  nearest  limit  of  distinct  vision  is  not  above 
half  that  of  a  person  of  ordinary  sight,  can  see  minute  objects  more  clearly; 
his  eyes  having,  in  fact,  the  same  magnifying  power  which  those  of  the  other 
would  possess,  if  aided  by  a  convex  glass  that  would  enable  him  to  see  the 
object  distinctly  at  the  shortest  distance.  But,  as  the  myopic  structure  of  the 
eye  incapacitates  its  possessor  from  seeing  objects  clearly  at  even  a  moderate 
distance,  it  is  desirable  to  apply  a  correction ;  and  this  is  done,  by  simply  in- 
terposing between  the  object  and  the  eye  &  concave  lens,  of  which  the  curvature 
is  properly  adapted  to  compensate  for  the  excess  of  that  of  the  organ  itself. — 
On  the  other  hand,  in  the  presbyopic  eye,  the  curvature  and  refractive  power 
are  not  sufficient  to  bring  to  a  focus,  on  the  retina,  rays  which  were  previously 
divergent  in  a  considerable  or  even  in  a  moderate  degree ;  and  indistinct  vision 
in  regard  to  all  near  objects  is,  therefore,  a  necessary  consequence,  whilst  distant 
objects  are  well  seen.  This  defect  is  remedied  by  the  use  of  convex  lenses,  which 
make  up  for  the  deficiency  of  the  curvature. — We  commonly  meet  with  myopia 
in  young  persons,  and  with  presbyopia  in  old ;  but  this  is  by  no  means  the  in- 
variable rule;  for  even  aged  persons  are  sometimes  "short-sighted,"  and  "long- 
sightedness" is  occasionally  met  with  amongst  the  young.  In  choosing  spec- 
tacles, for  the  purpose  of  correcting  the  errors  of  the  eye,  it  is  of  great  conse- 
quence not  to  make  an  over-compensation  ;  for  this  has  a  tendency  to  increase 
the  defect,  besides  occasioning  great  fatigue  in  the  employment  of  the  sight. 
It  may  be  easily  found  when  a  glass  of  the  right  power  has  been  selected,  by 
inquiring  of  the  individual  whether  it  alters  the  apparent  size  of  the  objects,  or 
only  renders  them  distinct.  If  it  alter  the  size  (increasing  it,  if  it  be  a  convex 
lens,  and  diminishing  it,  if  it  be  a  concave),  its  curvature  is  too  great ;  whilst 


878 


OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 


if  it  do  not  disperse  the  haze,  it  is  not  sufficiently  powerful.  In  general  it  is 
better  to  employ  a  glass  which  somewhat  under-compensates  the  eye,  than  one 
which  is  of  a  curvature  at  all  too  high;  since,  with  the  advance  of  years  in 
elderly  persons,  a  progressive  increase  in  power  is  required ;  and,  as  young  per- 
sons grow  up  to  adult  age,  they  should  endeavor  to  dispense  with  the  aid  of 
spectacles.  • 

880.  Many  other  interesting  inquiries,  respecting  the  action  of  the  Eye  as 
an  optical  instrument,  suggest  themselves  to  the  Physical  philosopher ;  but  the 
foregoing  are  the  chief  in  which  the  Physiologist  is  concerned ;  and  we  shall 


Fig.  210. 


Fig.  211. 


Distribution  of  Capillaries  in  the  Vascular 
layer  of  the  Retina. 


Part  of  the  Retina  of  a  Frog,  seen  from 
the  outer  surface,  showing  the  staff-like 
bodies  of  "  Jacob's  Membrane." 


now  proceed,  therefore,  to  consider  the  share  which  the  Nervous  apparatus  per- 
forms in  the  phenomena  of  vision. — The  Optic  Nerve,  at  its  entrance  into  the 
eye,  divides  itself  into  numerous  small  fasciculi  of  ultimate  fibrils ;  and  these 
appear  to  spread  themselves  out,  and  to  inosculate  with  each  other  by  an  ex- 
change of  fibrils,  so  as  to  form  a  netlike  plexus.  There  is  considerable  diffi- 
culty, however,  in  the  precise  determination  of  the  course  of  the  nerve-fibres  in 

Fig.  212. 


Vertical  section  of  the  Human  Retina  and  Hyaloid  Membrane:  h.  Hyaloid  membrane,  h'.  Nuclei  on  its 
inner  surface,  c.  Layer  of  transparent  cells,  connecting  the  hyaloid  and  retina,  c'.  Separate  cell  enlarged 
by  imbibition  of  water,  n.  Gray  nervous  layer,  with  its  capillaries.  1.  Its  fibrous  lamina.  2.  Its  vesicular 
lamina.  1'.  Shred  of  fibrous  lamina  detached.  2'.  Vesicle  and  nucleus  detached,  g.  Granular  layer.  3. 
Light  lamina  frequently  seen,  g'.  Detached  nucleated  particle  of  the  granular  layer.  TO.  Jacob's  mem- 
brane, m'.  Appearance  of  its  particles,  when  detached,  m".  Its  outer  surface.  Magnified  320  diameters. 


SENSE   OF   VISION.  879 

the  Retina,  on  account  of  their  minute  size,  and  the  absence  of  their  distinctive 
characters.  According  to  Mr.  Bowman,1  the  tubular  membrane  and  the  white 
substance  of  Schwann  are  deficient ;  and  only  the  central  part  of  the  nerve- 
fibre,  or  axis-cylinder,  is  continued  into  this  expansion.  The  plexus  of  nerve- 
fibres  comes  into  relation  with  a  plexus  of  capillary  vessels  (Fig.  210),  very 
minutely  distributed ;  and  also  with  a  layer  of  cells,  which  constitutes  the  in- 
ternal layer  of  the  true  Retina,  and  which  so  closely  resembles  those  of  the 
cortical  substance  of  the  Brain  that  there  can  be  no  reasonable  doubt  of  their 
correspondence  in  function.3  We  have  here,  then,  all  the  elements  of  an  ap- 
paratus for  the  origination  of  changes  in  the  nervous  trunks,  in  a  fully  deve- 
loped condition ;  and  it  can  scarcely  be  doubted 
that  the  essential  parts  of  the  same  structures  Fig-  213. 

exist  in  connection  with  the  peripheral  expan- 
sions of  the  nerves  distributed  to  other  sensory 
organs. — The  true  Retina  is  covered  externally 
by  a  very  peculiar  investment,  the  "  Membrane 
of  Jacob"  (Fig.  213),  which  separates  it  from 
the  pigmentary  layer.  This  seems  to  be  compos- 
ed of  cells  having  a  cylindrical  form  ;  and  these 
are  sometimes  arranged  vertically  to  the  surface 
of  the  membrane,  so  that  their  extremities  only 
are  seen  j  whilst  in  other  instances  they  are 
found  to  present  an  imbricated  arrangement, 
lying  over  each  other  obliquely,  in  which  case  Outer  surface  of  the  Retina,  showing 

they    are    of    considerable     length    (Fig.    213).      the  membrane  of  Jacob,  partially  detach- 

They  are   remarkable   for   the   rapidity  with    ed>  After  Jaeob- 

which  they  undergo  alterations    after   death, 

and  especially  for  the  changes  in  their  form  which  are  produced  by  the  action 

of  water. 

881.  The  following  statements  on  the  Limits  of  Human  Vision,  in  regard  to 
the  possible  minuteness  of  the  objects  of  which  it  can  take  cognizance,  compre- 
hend the  result  of  numerous  inquiries  made  by  Prof.  Ehrenberg,  with  the  view 
of  calculating  the  ultimate  power  of  the  Microscope.3  In  opposition  to  the 
generally  received  opinion,  Ehrenberg  arrived  at  the  conclusion  that,  in  regard 
to  the  extreme  limits  of  vision,  there  is  little  difference  amongst  persons  of 
ordinarily  good  sight,  whatever  may  be  the  focal  distance  of  their  eyes.  The 
smallest  square  magnitude  usually  visible  to  the  naked  eye,  either  of  white  par- 
ticles on  a  black  ground,  or  of  black  upon  a  white  or  light-colored  ground,  is 
about  the  l-405th  of  an  inch.  It  is  possible,  by  the  greatest  condensation  of 
light,  and  excitement  of  the  attention,  to  recognize  magnitudes  between  the 
1 -405th  and  l-540th  of  an  inch ;  but  without  sharpness  or  certainty.  Bodies 
which  are  smaller  than  these  cannot  be  discerned  with  the  naked  eye  when 
single }  but  may  be  seen  when  placed  in  a  row.  Particles  which  powerfully 
reflect  light,  however,  may  be  distinctly  seen  when  not  half  the  size  of  the  legist 
of  the  foregoing;  thus,  gold  dust,4  of  the  fineness  of  l-1125th  of  an  inch,  may 
be  discerned  with  the  naked  eye  in  common  daylight.  The  delicacy  of  vision 

1  "Lectures  on  the  Parts  concerned  in  the  Operations  on  the  Eye,"  p.  81. 

2  This  doctrine,  which  has  been  taught  by  the  Author  for  many  years,  has  latterly  re- 
ceived full  confirmation  from  the  researches  of  Mr.  H.  Gray  upon  the  development  of  the 
Eye  ;  for  he  has  shown  that  the  Retina  is  really  an  offset  put  forth  (so  to  speak)  from  the 
Optic  Ganglion,  and  that  the  Optic  Nerve  is  to  be  considered  in  the  light  of  a  commissure. 
(See  "Philos.  Transact.,"  1850.) 

3  Taylor's  "Scientific  Memoirs,"  vol.  i.  p.  576. 

4  Ehrenberg  mentions  that  he  obtained  the  finest  particles  of  gold  by  scraping  gilt 
brass ;  by  filing  pure  gold,  he  always  obtained  much  coarser  particles. 


880      OF  SENSATION,  AND  THE  ORGANS  OP  THE  SENSES. 

is  far  greater  for  lines  than  for  mere  points ;  since  opaque  threads  of  14900th 
of  an  inch  in  diameter  (about  half  the  diameter  of  the  Silk-worm's  fibre)  may 
be  discerned  with  the  naked  eye,  when  held  towards  the  light.  The  degree  in 
which  the  attention  is  directed  to  them  has  a  great  influence  on  the  readiness 
with  which  very  minute  objects  can  be  perceived;  and  Ehrenberg  remarks  that 
there  is  a  much  greater  difference  amongst  individuals  in  this  respect  than 
there  is  in  regard  to  the  absolute  limits  of  vision.  Many  persons  can  distinctly 
see  such  objects,  when  their  situation  is  exactly  pointed  out  to  them,  who 
cannot  otherwise  distinguish  them;  and  the  same  is  the  case  with  persons  of 
acuter  perception,  with  respect  to  objects  at  distances  greater  than  those  at 
which  they  can  see  most  clearly.  " I  myself/'  says  Ehrenberg,  "cannot  see 
l-2700th  of  an  inch,  black  or  white,  at  twelve  inches'  distance;  but  having 
found  it  at  from  four  or  five  inches'  distance,  I  can  remove  it  to  twelve  inches, 
and  still  see  the  object  plainly."  Similar  phenomena  are  well  known  in  regard 
to  a  balloon  or  a  faint  star  in  a  clear  sky,  or  a  ship  in  the  horizon :  we  easily 
see  them  after  they  have  been  pointed  out  to  us;  but  the  faculty  of  rapidly 
descrying  depends  on  the  habit  of  using  the  eyes  in  search  of  such  objects,  and 
of  attending  to  the  sensory  impressions  received  through  them. 

882.  The  amount  of  light  admitted  to  the  Eye  is  regulated  by  the  contraction 
and  dilatation  of  the  Pupil,  which  is  due  to  the  muscularity  of  the  Iris;  its 
smallest  diameter  being  about  l-20th,  and  its  largest  about  l-3d  of  an  inch. 
The  converging  fibres  of  the  iris  are  easily  made  out,  as  the  membrane  is  prin- 
cipally composed  of  them ;  they  have  the  general  characters  of  the  non-striated 
-muscular  fibre,  but  their  nuclei  are  rounder  and  more  loosely  attached  to  the 
contractile  material.  Although  the  principal  direction  taken  by  the  fibres  is 
from  the  circumference  towards  the  centre  of  the  iris,  yet  their  course  is  by  no 
means  constantly  straight,  and  they  frequently  anastomose  with  each  other  in 
their  passage;  these  anastomoses  are  most  frequent  near  the  pupil.  The  circu- 
lar fibres  of  the  iris  are  by  no  means  so  distinct ;  and  rarely,  in  Man,  form 
more  than  a  somewhat  undefined  band,  immediately  surrounding  the  pupil,  and 
lying  in  front  of  the  radiating  fibres.  Although  the  iris  is  so  vascular,  that 
some  anatomists  have  endeavored  to  explain  its  movements  on  the  hypothesis 
that  they  constitute  a  sort  of  erection,  there  is  no  ground  for  this  idea ;  and  it 
is  more  plainly  demonstrated  in  many  of  the  lower  animals  than  it  is  in  Man, 
that  the  movements  of  the  Iris  are  truly  muscular,  since  we  find  the  annular  as 
well  as  the  radiating  fibres  very  distinct,  and  in  Birds  (many  of  which  seem  to 
possess  a  power  of  voluntarily  regulating  the  diameter  of  the  pupil)  the  former 
are  striated.  The  contraction  of  the  annular  fibres,  whereby  the  diameter  of 
the  pupil  is  diminished,  is  effected,  as  already  explained  (§  724),  through  the 
instrumentality  of  the  3d  Pair  of  nerves;  the  contraction  of  the  radiating 
fibres,  on  the  other  hand,  whereby  the  pupil  is  dilated,  is  under  the  government 
of  the  Sympathetic  (§  847).  The  contraction  of  the  Pupil  takes  place,  as  we 
have  seen,  not  merely  for  the  purpose  of  excluding  superfluous  light  from  the 
eye,  but  also  that  the  most  divergent  rays  may  be  cut  off,  when  the  object  is 
brought  near  the  convex  surface  (§  878). 

[Prof.  Julius  Budge  and  Augustus  Waller  have  discovered  the  very  inte- 
resting fact,  that  irritation  of  the  cervical  trunks  of  the  sympathetic  nerve, 
by  means  of  the  magneto-electric  machine,  produces  an  extraordinary  dilatation 
of  the  pupil;  and  this  alike  in  the  rabbit,  in  which  this  trunk  is  isolated  from 
that  of  the  pneumogastric,  and  in  the  cat  and  dog,  in  which  the  two  trunks  are 
united.  The  phenomenon,  they  remark,  is  as  constant  as  the  contraction  of 
the  leg  when  the  sciatic  nerve  is  galvanized.  Thus  is  explained  the  permanent 
contraction  of  the  pupil  after  section  of  the  sympathetic  nerve  in  the  neck, 
which  was  first  observed  by  Petit  in  1712,  but  which,  though  subsequently 
verified  by  other  observers,  has  never  led  to  more  than  a  surmise  that  the  cer- 


SENSE   OF   VISION.  881 

vical  portion  of  the  sympathetic  might  afford  the  dilating  power.  By  galvaniz- 
ing the  third  pair  and  the  cervical  sympathetic  alternately,  alternate  contraction 
and  dilatation  of  the  pupil  are  produced ;  but  with  this  difference,  that  the  contrac- 
tion is  immediate,  as  is  also  the  return  of  the  iris  to  its  previous  state  after  the 
irritation  is  withdrawn,  whilst,  on  the  other  hand,  the  dilatation  requires  some 
seconds  to  attain  its  maximum,  and  the  subsequent  return  of  the  iris  to  its  pre- 
vious condition  is  slow.  Moreover,  the  third  pair  loses  its  power  of  conducting 
irritation  after  being  several  times  excited  in  this  manner,  and  also  very  soon 
after  death  ;  whilst  the  sympathetic  retains  it  longer. 

The  authors  next  applied  themselves  to  determine  the  precise  centre  of  this 
power,  and  they  ascertained,  in  the  first  place,  by  galvanizing  the  undivided 
trunk  in  the  rabbit,  that  irritation  of  any  part  of  the  cervical  portion  of  the 
sympathetic,  from  the  first  to  the  last  ganglion  inclusive,  would  produce  this 
result;  but  that  below  the  last  cervical  ganglion,  no  such  effect  could  be  pro- 
duced by  irritation.  On  exposing  the  spinal  cord,  they  found  that  irritation  of 
any  part  of  it  between  the  first  cervical  and  sixth  dorsal  vertebrae  (which  they 
hence  designate  the  cilio-spinal  region)  would  produce  dilatation  of  the  pupil ; 
but  that  the  effect  was  most  decided  in  the  centre  of  this  region,  the  maximum 
being  at  the  junction  of  the  second  and  third  dorsal  vertebrae,  and  decreasing  in 
intensity  on  passing  towards  either  of  its  limits.  When  both  of  the  sympathetic 
trunks  are  entire,  irritation  of  this  region  produces  contraction  in  both  pupils 
equally;  but  when  one  of  the  sympathetic  trunks  is  divided,  the  dilatation  does 
not  take  place  on  that  side ;  and  if  both  be  divided,  no  irritation  of  the  spinal 
cord  produces  any  effect  on  the  pupil.  It  is  sufficient  to  irritate  one  side  of  the 
spinal  cord  only,  to  produce  dilatation  of  both  pupils ;  but  if  the  spinal  cord  be 
divided  longitudinally,  and  the  two  halves  be  kept  asunder  by  a  slip  of  glass, 
irritation  of  one  side  then  acts  only  on  the  pupil  of  that  side.  When  the  spinal 
cord  is  divided  transversely  at  different  points,  it  is  found  that  irritation  of  any 
part  that  is  isolated  from  the  centre  of  the  cilio-spinal  region  is  unproductive  of 
effect.  When  the  spinal  cord  was  removed,  and  the  galvanism  was  applied  to 
the  dura  mater  lining  its  canal,  this  limitation  was  still  more  precise;  for  it  was 
then  found  that  in  no  other  point  was  any  effect  produced  than  at  the  inter- 
vertebral  space  between  the  second  and  third  dorsal  vertebrae.  Thus  it  seems 
obvious  that  the  motor  fibres  on  which  this  action  depends  issue  from  the  spinal 
cord  with  the  second  dorsal  nerve ;  and  this  corresponds  with  the  results  of 
dissection,  as  compared  with  the  lowest  limit  of  the  influence  of  the  sympa- 
thetic trunk  over  the  movement  of  the  pupil.  All  the  causes  which  diminish 
muscular  irritability  after  death,  such  as  imperfect  nutrition  of  the  animal 
lesions,  of  the  medulla  oblongata,  &c.,  dimmish  or  destroy  the  power  of  the 
cilio-spinal  region  over  the  pupils;  and  in  all  cases  it  is  to  be  noted  that  after 
death  the  power  gradually  recedes  from  the  extremities  of  the  cilio-spinal  region 
towards  its  centre. 

The  authors  then  proceed  to  study  the  action  of  the  intercranial  nerves ;  and, 
in  the  first  place,  that  of  the  fifth  pair,  respecting  which  there  has  been  so  much 
contrariety  of  opinion.  In  order  to  remove  all  sources  of  fallacy  so  far  as  possi- 
ble, they  have  divided  all  the  other  nerves  connected  with  the  eye  (including 
the  cervical  sympathetic);  and  they  have  then  found  that  sections  of  the  oph- 
thalmic branch  of  the  fifth  pair,  or  of  the  trunk  from  which  it  is  given  off, 
causes  a  slow  and  gradual  constriction,  which  does  not  commence  for  a  minute 
or  two  after  the  section,  and  does  not  attain  its  maximum  for  as  much  more. 
The  constriction  is  very  decided,  the  pupil  being  reduced  from  three  lines  in 
diameter  to  one.  If,  instead  of  division  of  the  nerve,  mechanical  or  galvanic 
irritation  be  applied  to  it,  the  same  effect  is  produced,  but  in  a  less  degree. 
The  constriction  is  in  no  way  permanent,  but  departs  gradually.  After  section 
of  the  optic  nerve,  section  of  the  third  pair  does  not  produce  any  change  in  the 
56 


882      OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 

diameter  of  the  pupil.  The  fourth  and  sixth  pairs,  moreover,  have  not  appeared 
to  the  authors  to  possess  any  influence  over  the  movements  of  the  iris.  If  the 
cervical  sympathetic  be  galvanized  without  waiting  for  the  gradual  departure 
of  the  constriction  produced  by  the  section  of  the  fifth  pair,  it  is  found  to  be 
powerless  to  overcome  this  constriction.  If,  moreover,  the  fifth  pair  be  exposed 
and  its  trunk  be  divided  progressively  from  the  centre  towards  the  eye,  it  is 
found  that  so  soon  as  the  section  is  carried  in  front  of  the  anterior  portion  of 
the  Gasserian  ganglion,  the  power  of  the  sympathetic  over  the  pupil  is  entirely 
lost.  Hence  it  seems  evident  that  the  sympathetic  fibres  which  have  this  func- 
tion pass  through  the  Grasserian  ganglion;  and  by  other  experiments  it  may  be 
shown  that  they  form  part  of  the  ophthalmic  division  of  the  fifth  pair. — ED.]1 
883.  The  sense  of  Vision  depends,  in  the  first  place,  on  the  transference  to 
our  minds  of  the  picture  which  is  formed  upon  the  retina;  this  picture  puts  us  in 
possession  of  the  outlines,  lights  and  shades,  colors,  and  relative  positions,  of 
the  objects  before  us;  and  all  the  ideas  respecting  the  real  forms,  distances, 
&c.,  of  bodies,  which  we  found  upon  these  data,  must  be  considered  in  the  light 
of  perceptions,  either  instinctive  or  acquired.  Many  of  these  are  derived 
through  the  combination,  in  our  minds,  of  the  Visual  sensations,  with  those 
derived  from  the  sense  of  Touch.  Thus,  to  take  a  most  simple  illustration,  the 
idea  of  smoothness  is  one  essentially  tactile ;  and  yet  it  constantly  occurs  to  us, 
on  looking  at  a  surface  which  reflects  light  in  a  particular  manner.  But,  if  it 
were  not  for  the  association,  which  experience  leads  us  to  form,  of  the  connec- 
tion between  polish  as  seen  by  the  eye,  and  smoothness  as  felt  by  the  touch,  we 
should  not  be  able  to  determine,  as  we  now  can  do,  the  existence  of  both  these 
qualities,  from  an  impression  communicated  to  us  through  either  sense  singly. 
The  general  fact  that,  in  Man,  the  greater  part  of  those  notions  of  the  external 
world,  by  which  his  actions  in  the  adult  state  are  guided,  are  acquired  by  the 
gradual  association  of  the  perceptions  derived  through  the  Sight  and  through 
the  Touch,  is  substantiated  by  amply  sufficient  evidence.  This  evidence  is 
chiefly  derived  from  observations  made  upon  persons  born  blind,  to  whom  sight 
has  been  communicated  by  an  operation  at  a  period  of  life  which  enabled  them 
to  give  an  accurate  description  of  their  sensations.  The  case  recorded  by 
Oheselden  is  one  of  the  most  interesting  of  these.  The  youth  (about  twelve 
years  of  age),  for  some  time  after  tolerably  distinct  vision  had  been  obtained, 
saw  every  thing  flat  as  in  a  picture,  simply  receiving  the  consciousness  of  the 
impression  made  upon  his  retina;  and  it  was  some  time  before  he  acquired  the 
power  of  judging,  by  his  sight,  of  the  real  forms  and  distances  of  the  objects 
around  him.  An  amusing  anecdote  recorded  of  him  shows  the  complete  want 
x)f  natural  or  intuitive  connection  which  there  is  in  Man  between  the  ideas 
formed  through  visual  and  through  tactile  sensations.  He  was  well  acquainted 
with  a  Dog  and  a  Cat  by  feeling ;  but  could  not  remember  their  respective 
characters  when  he  saw  them.  One  day,  when  thus  puzzled,  he  took  up  the 
Cat  in  his  arms,  and  felt  her  attentively,  so  as  to  associate  the  two  sets  of  ideas; 
and  then,  setting  her  down,  said,  "So,  puss,  I  shall  know  you  another  time." 
— A  similar  instance  has  come  under  the  Author's  own  knowledge;  but  the 
subject  of  it  was  scarcely  old  enough  to  present  phenomena  so  striking.  One 
curious  circumstance  was  remarked  of  him,  which  fully  confirms  (if  confirmation 
were  wanting)  the  view  here  given.  For  some  time  after  his  sight  was  tolera- 
bly clear,  the  lad  preferred  finding  his  way  through  his  father's  house,  to  which 
he  had  been  quite  accustomed  when  blind,  by  touch  rather  than  by  sight,  the 
use  of  the  latter  sense  appearing  to  perplex  rather  than  to  assist  him ;  but  when 
learning  a  new  locality,  he  employed  his  sight,  and  evidently  perceived  the 

1  "Brit,  and  For.  Med.-Chir.  Rev.,"  Jan.  1852,  from  "Gazette  Medicale  de  Paris," 
Nos.  41  and  44,  1851. 


SENSE   OF   VISION.  883 

increase  of  facility  which  he  derived  from  it. — The  question  has  been  proposed, 
whether  a  person  born  blind,  who  was  able  by  the  sense  of  Touch  to  distinguish 
a  cube  from  a  sphere,  would,  on  suddenly  obtaining  his  Sight,  be  able  to  dis- 
tinguish them  by  the  latter  sense.  This  question  was  answered  by  Locke  in 
the  negative;  and,  as  appears  from  the  facts  just  stated,  with  justice. 

884.  The  actions  performed  by  many  new-born  animals  do  not  constitute  any 
valid  objection  to  this  view ;  for  all  that  is  indicated  by  them  is,  that  certain 
sensations  give  rise  to  movements  adapted  to  supply  the  wants  to  which  they 
relate.     Such  instinctive  actions  are,  as  already  pointed  out,  much  more  nume- 
rous in  the  lower  Animals  than  in  the  higher,  and  in  the  young  of  the  Human 
species  than  in  the  adult  (§  792)  ;  and  they  do  not  afford  any  proof  that  definite 
notions,  such  as  we  acquire,  of  the  forms  and  properties  of  external  objects  are 
possessed  by  the  animals  which  exhibit  them. — We  shall  now  examine,  a  little 
more  in  detail,  into  the  means  by  which  -we  gain  such  notions,  and  the  data  on 
which  they  are  founded. 

885.  The  first  point  to  be  determined  is  one  which  has  been  a  fruitful  source 
of  discussion — the  cause  of  Erect  Vision,  the  picture  upon  the  retina  being  in- 
verted.    Many  solutions  of  it  have  been  attempted ;  but  they  are  for  the  most 
part  rather  specious  than  really  satisfactory.     That  which  has  been  of  late  years 
the  most  in  vogue  is  founded  upon  what  was  styled  the  "  law  of  visible,  direc- 
tion," which  has  been  supported  by  Sir  D.  Brewster,  and  other  eminent  Philo- 
sophers.    This  law  aflirms,  that  every  object  is  seen  in  the  direction  of  the 
perpendicular  to  that  point  of  the  retina  on  which  its  image  is  formed ;  or,  in 
other  words,  that,  as  all  the  perpendiculars  to  the  several  points  of  the  inner 
surface  of  a  sphere  meet  in  the  centre,  the  line  of  direction  of  any  object  is 
identical  with  the  prolonged  radius  of  the  sphere,  drawn  from  the  point  at  which 
its  image  is  made  upon  the  retina.     Upon  close  examination,  however,  it  is  found 
that  this  law  cannot  be  optically  correct ;  since  the  lines  of  direction  cross  each 
other  at  a  point  much  anterior  to  the  centre  of  the  globe ;  as  may  be  determined 
by  drawing  a  diagram  upon  a  large  scale,  and  laying  down  the  course  of  the 
rays  received  by  the  eye,  according  to  the  curvatures  and  refractive  powers  of 
its  different  parts.     In  this  manner  it  has  been  determined  by  Volkmann,  that 
the  lines  of  direction  cross  each  other  in  a  point  a  little  behind  the  crystalline 
lens  j  and  that  they  must  thus  fall  at  such  different  angles  on  different  points  of 
the  retina,  that  no  general  law  can  be  laid  down  respecting  them.     Moreover, 
even  supposing  that  such  a  law  were  a  correct  statement  of  the  general  fact,  it 
would  not  afford  any  real  assistance  in  explaining  the  phenomenon  \  since,  after 
all,  it  is  requisite  to  assume  an  intuitive  application  of  it,  in  supposing  the  mind 
to  derive  its  ideas  of  the  relative  situations  of  objects  from  the  imagined  line  of 
direction. — A  much  simpler  and  more  direct  explanation  may  be  given.     We 
must  always  bear  that  in  mind,  which  we  have  had  occasion  to  notice  in  regard 
to  all  the  other  Senses — the  broad  line  of  distinction  between  the  sensation,  and 
the  perception  or  elementary  notion;  the  latter  being  the  result  of  the  operation 
of  the  Sensory  impression  on  the  Cerebrum,  but  having  a  nature  as  distinct  as 
that  of  any  other  effect  can  be  from  that  of  its  cause.     Further,  it  has  been  shown 
that  there  is  in  Man  a  complete  absence  of  any  relation  but  such  as  experi- 
ence develops,  between  the  perceptions  derived  through  the  Sight,  and  those  ac- 
quired from  the  Touch.     Hence  there  is  no  more  difficulty  in  understanding,  that 
an  inverted  picture  upon  the  retina  should  convey  to  us  a  notion  of  the  external 
world,  which  harmonizes  with  that  acquired  through  the  sense  of  touch,  than 
there  is  in  comprehending  the  existence  of  any  of  those  intuitive  perceptions  of 
animals,  which  are  so  much  more  removed  from  the  teachings  of  our  own  ex- 
perience (§  792).     It  is  justly  remarked  by  Miiller  that,  "if  we  do  see  objects 
inverted  [or  rather,  if  the  picture  on  the  retina  be  inverted],  the  only  proof  we 
can  possibly  have  of  it  is  that  afforded  by  the  study  of  the  laws  of  Optics ;  and,  if 


884  OF   SENSATION,   AND   THE   ORGANS   OF   THE   SENSES. 

everything  is  seen  reversed,  the  relative  position  of  the  objects  remains  un- 
changed. Hence  it  is,  also,  that  no  discordance  arises  between  the  sensations 
of  inverted  vision  and  those  of  touch,  which  perceives  everything  in  its  erect 
position;  for  the  images  of  all  objects,  even  of  our  own  limbs, "on  the  retina, 
are  equally  inverted,  and  therefore  maintain  the  same  relative  position.  Even 
the  image  of  our  hand,  when  used  in  touch,  is  inverted."  From  what  has  been 
stated,  it  would  appear  quite  conceivable,  that  a  person  just  end  owed  with  sight, 
should  not  at  first  know,  by  his  visual  powers,  whether  a  pyramid  placed  before 
his  eyes  is  the  same  body,  and  in  the  same  position,  as  one  with  which  he  has 
become  acquainted  by  the  touch ;  and,  if  this  be  admitted,  the  inference  neces- 
sarily follows,  that  the  notion  of  erectness,  which  we  form  by  the  combined  use 
of  our  eyes  and  our  hands,  is  really  the  product  of  experience  in  ourselves, 
whilst  it  is  probably  innate  or  intuitional  in  the  lower  Animals. 

886.  The  cause  of  Single  Vision  with  the  two  Eyes  has  in  like  manner  been 
the  subject  of  much  discussion,  since  the  mode  in  which  we  are  affected  by 
the  two  simultaneous  impressions  is  quite  different  from  that  in  which  we 
derive  our  knowledge  of  external  things  through  the  other  senses.  Some 
have  even  asserted  that  we  do  not  really  employ  both  eyes  simultaneously,  but 
that  the  mind  is  affected  by  the  image  communicated  by  one  only ;  and  this 
idea  might  seem  to  be  confirmed  by  the  fact  heretofore  mentioned  (§  861),  re- 
specting the  alternate  use  of  the  two  eyes,  when  they  are  looking  through  two 
differently  colored  media.  But  it  is  easily  disproved  in  other  ways. — It  will 
presently  be  shown  that  all  our  estimates  of  the  forms  of  bodies  depend  on 
the  combination,  by  the  mind,  of  the  images  simultaneously  transmitted  by  the 
two  eyes ;  and  our  knowledge  of  distances  is  in  great  part  obtained  in  like 
manner.  One  condition  of  Single  Vision,  however,  seems  to  be  this,  that  the 
two  images  of  the  object  should  be  formed  on  parts  of  the  two  retinae  which 
are  accustomed  to  act  in  concert  ;  and  habit  appears  to  be  the  chief  means  by 
which  this  conformity  is  produced.  There  can  be  no  doubt,  however,  that 
double  images  are  continually  being  conveyed  to  the  Sensorium  ;  but  that,  from 
their  want  of  force  and  distinctness,  and  from  the  attention  being  fixed  on 
something  else,  we  do  not  take  cognizance  of  them.  This  may  be  shown  by  a 
very  simple  experiment.  If  two  fingers  be  held  up  before  the  eyes,  one  in 
front  of  the  other,  and  vision  be  directed  to  the  more  distant,  so  that  it  is  seen 
singly,  the  nearer  will  appear  double ;  while,  if  the  nearer  one  be  regarded  more 
particularly,  so  as  to  appear  single,  the  more  distant  will  be  seen  double.  A 
little  consideration  will  show,  therefore,  that  our  minds  must  be  continually 
affected  with  sensations,  which  cannot  be  united  into  the  idea  of  a  single  image; 
since,  whenever  we  direct  the  axes  of  our  eyes  towards  any  object,  everything 
else  will  be  represented  to  us  as  double ;  but  we  do  not  ordinarily  perceive  this, 
from  our  minds  being  fixed  upon  a  clear  and  distinct  image,  and  disregarding, 
therefore,  the  vague  undefined  images  formed  by  objects  at  a  different  focus. 
Of  this  it  is  very  easy  to  convince  one's  self. — It  is,  moreover,  evident,  from  this 
experiment,  that  double  vision  cannot  result  from  want  of  symmetry  in  the 
position  of  the  images  upon  the  retina,  to  which  some  have  attributed  it ;  for  it 
answers  equally  well  if  the  line  of  the  two  fingers  be  precisely  in  front  of  the 
nose,  so  that  the  inclination  of  both  eyes  towards  either  object  is  equal; 
the  position  of  the  images  of  the  second  object  must  then  be  at  the  same 
distance  on  either  side  from  the  central  line  of  the  retina,  and  yet  they  are 
represented  to  the  mind  as  double.  Hence  it  seems  clear  that  singleness  of 
vision  is  also  dependent  upon  the  convergence  of  the  optic  axes  in  the  object  to 
which  our  gaze  is  directed. — Attempts  have  been  made  to  explain  the  pheno- 
mena of  Single  Vision  by  the  peculiar  decussation  of  the  Optic  Nerves  formerly 
described  (§  742),  it  being  supposed  that  only  one  Optic  Ganglion  would  be 
affected  by  an  impression  made  upon  both  Retinae.  This  explanation,  however, 


SENSE   OF   VISION.  885 

even  supposing  the  fact  to  be  as  stated,  would  be  far  from  affording  the  solution 
of  the  problem  •  and  it  would  be  entirely  inapplicable  to  that  very  important 
series  of  phenomena  to  be  next  described,  which  show  how  large  an  amount  of 
information  we  derive,  not  merely  from  the  repetition,  but  from  the  difference, 
of  the  sensory  impressions  made  by  the  same  object  upon  our  two  retinae;  and 
which  indicate  that  here,  as  in  the  case  of  erect  vision,  the  mental  interpretation 
of  the  sensory  impressions  is  a  process  altogether  removed  from  the  simple 
affection  of  the  consciousness  by  those  impressions,  and  is  not  to  be  accounted 
for  by  any  structural  arrangements  of  the  Sensorial  apparatus. 

887.  We  shall  next  consider  the  mode  in  which  our  notion  of  the  solid  forms 
and  relative  projection  of  objects  is  acquired ;  on  which  great  light  has  been 
thrown  by  the  interesting  experiments  of  Prof.  Wheatstone.1  It  seems  per- 
fectly evident,  both  from  reason  and  experience,  that  the  flat  picture  upon 
the  retina,  which  is  the  immediate  source  of  our  sensation,  could  not  itself  con- 
vey to  our  minds  any  notion  but  that  of  a  corresponding  plane  surface.  In 
fact,  any  notion  of  solidity,  which  might  be  formed  by  a  person  who  had  never 
had  the  use  of  more  than  one  eye,  would  entirely  depend  upon  the  combination 
of  his  visual  and  tactile  sensations.  This  view  is  fully  confirmed  by  the  case 
already  referred  to,  as  recorded  by  Cheselden.  The  first  visual  idea  formed  by 
the  youth  was  that  the  objects  around  him  formed  a  flat  surface,  which  touched 
his  eyes,  as  they  had  previously  been  in  contact  with  his  hands ;  and  after  this 
notion  had  been  corrected,  through  the  education  of  his  sight  by  his  touch,  he 
fell  into  the  converse  error  of  supposing  that  a  picture,  which  was  shown  to 
him,  was  the  object  itself  represented  in  relief  on  a  small  scale. — But  where 
both  eyes  are  employed,  it  has  been  ascertained  by  Prof.  Wheatstone  that  they 
concur  in  exciting  the  perception  of  solidity  or  projection,  which  arises  from  the 
mental  combination  of  the  two  dissimilar  pictures  formed  upon  the  two  retinae. 
It  is  easily  shown,  that  any  near  object  is  seen  in  two  different  modes  by  the 
two  eyes.  Thus  let  the  reader  hold  up  a  thin  book,  in  such  a  manner  that  its 
back  shall  be  exactly  in  front  of  his  nose,  and  at  a  moderate  distance  from  it ; 
lie  will  observe,  by  closing  first  one  eye  and  then  the  other,  that  his  perspective 
view  of  it  (or  the  manner  in  which  he  would  represent  it  on  a  plane  surface)  is 
very  different,  according  to  the  eye  with  which  he  sees  it.  With  the  right  eye, 
he  will  see  its  right  side,  very  much  foreshortened  j  with  the  left,  he  will  gain 
a  corresponding  view  of  the  left  side;  and  the  apparent  angles,  and  the  lengths 
of  the  different  lines,  will  be  found  to  be  very  different  in  the  two  views.  On 
looking  at  either  of  these  views  singly,  no  other  notion  of  solidity  can  be 
acquired  from  it  than  that  to  which  the  mind  is  conducted  by  the  association  of 
such  a  view  with  the  touch  of  the  object  which  it  represents.  But  it  is  capable 
of  proof,  that  the  mental  association  of  the  two  different  pictures  upon  the 
retinae  does  of  itself  give  rise  to  the  idea  of  solidity.  This  proof  is  afforded 
by  Prof.  Wheatstone' s  ingenious  instrument,  the  Stereoscope,  first  described  by 
him  in  1838.3 

1  "Philosophical  Transactions,"  1838  and  1852. 

2  Various  modifications  of  this  instrument  have  been  subsequently  introduced;  and 
there  is  one  which  has  recently  (1852)  come  into  very -extensive  use,  in  which  the  two 
monocular  pictures  placed  side  by  side,  as  in  Figs.  214,  215,  are  viewed  by  the  two  eyes 
respectively  through  two  prisms,  or  two  halves  of  a  convex  lens.     The  great  advantage  of 
this  instrument  is  its  portability  ;  but  it  is  limited  to  pictures  of  small  size,  since  the  dis- 
tance between  corresponding  points  of  the  two  pictures  must  not  exceed  the  distance 
between  the  centres  of  the  two  eyes  ;  and  it  is  incapable  of  many  adaptations  which  can 
be  made  with  the  mirror-stereoscope. — As  Sir  D.  Brewster  has  recently  put  forth  his 
claim  as  an  original  discoverer  in  regard  to  the  truths  of  binocular  vision  which  have  been 
established  by  the  Stereoscope,  on  the  strength  of  some  trivial  improvements  in  the  con- 
struction of  the  instrument,  the  Author  feels  it  due  to  Prof.  Wheatstone  to  state  his  own 
conviction,  founded  upon  a  careful  examination  of  the  whole  history  of  the  invention,  that 


886      OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 

888.  The  Stereoscope,  in  its  original  form,  essentially  consists  of  two  plane 
mirrors,  inclined  with  their  backs  to  one  another  at  an  angle  of  90°.  If  two 
perspective  drawings  of  any  solid  object,  as  seen  at  a  given  distance  with  the 
two  eyes  respectively,  such  as  those  at  A  and  B,  Fig.  214,  be  so  placed  before 
these  mirrors,  one  before  each,  that  their  two  images  shall  be  made  to  fall  upon 
the  corresponding  parts  of  the  two  retinae,  in  the  same  manner  as  the  two  images 
formed  by  the  solid  object  itself  would  have  done,  the  mind  will  perceive,  not 
a  single  representation  of  the  object,  nor  a  confused  union  of  the  two,  but  a 
projecting  or  receding  surface,  the  exact  counterpart  of  that  from  which  the 
drawings  were  made.1  The  solid  form  is  forcibly  impressed  on  the  mind,  even 
when  outlines  only  are  given,  especially  if  these  be  delineations  of  simple  geo- 

Fig.  214. 


metrical  figures,  easily  suggested  to  the  mind;  and  it  may  be  easily  shown  that 
the  very  same  outlines  will  suggest  different  conceptions,  according  to  the  mode 
in  which  they  are  placed.  Thus,  in  Fig.  215,  the  upper  pair  of  figures  A,  B, 
when  combined  in  the  Stereoscope,  convey  the  idea  of  a  projecting  truncated 
pyramid,  with  the  small  square  in  the  centre,  and  the  four  sides  sloping  equally 
away  from  it;  whilst  the  lower  pair  of  figures,  c,  D,  which  are  the  same  as  the 
upper,  but  transferred  to  the  opposite  sides,  no  less  vividly  bring  before  the  mind 
the  visual  conception  of  a  receding  pyramid,  still  with  the  small  square  in  the 
centre,  and  the  four  sides  sloping  equally  towards  it. — Prof.  Wheatstone  further 
shows,  by  means  of  the  Stereoscope,  that  similar  images,  differing  to  a  certain  ex- 
tent in  magnitude,  when  presented  to  the  corresponding  parts  of  the  two  retinae, 
give  rise  to  the  perception  of  a  single  object,  intermediate  in  size  between  the 
two  monocular  pictures.  Were  it  not  for  this,  objects  would  appear  single, 

the  entire  merit  of  the  idea — that  all  our  perception  of  solidity  derived  through  the  visual 
sense  is  consequent  upon  the  mental  combination  of  the  two  dissimilar  pictures  upon  the 
two  retinae — and  further  that  the  whole  merit  of  the  realization  of  that  idea  by  means  of 
the  mirror-stereoscope,  long  before  Sir  D.  Brewster's  attention  had  been  given  to  the  sub- 
ject at  all — belongs  to  Prof.  Wheatstone. 

1  The  most  striking  effect  is  produced  by  two  photographic  pictures,  taken  at  the  same 
time  by  two  cameras,  so  placed  that  their  axes  shall  form  the  same  angle  with  each  other 
as  that  which  the  axes  of  the  two  eyes  would  form  when  looking  at  the  same  object.  This 
adaptation,  though  the  credit  has  been  assumed  by  others,  was  originally  devised  by  Prof. 
Wheatstone. 


SENSE   OF   VISION. 


887 


only  when  at  an  equal  distance  from  both  eyes,  so  that  their  pictures  upon  the 
retina  are  of  the  same  size;  which  will  only  happen  when  they  are  directly  in 
front  of  the  median  line  of  the  face.  Again,  if  pictures  of  dissimilar  objects  be 
simultaneously  presented  to  the  two  eyes,  the  consequence  will  be  similar 
to  that  which  is  experienced  when  the  rays  come  to  the  eye  through  two 
differently  colored  media;  the  two  images  do  not  coalesce,  nor  do  they  appear 
permanently  superposed  upon  one  another;  but  at  one  time  one  image  pre- 
dominates to  the  exclusion  of  the  other,  and  then  the  other  is  seen  alone; 
and  it  is  only  at  the  moment  of  change,  that  the  two  seem  to  be  intermingled. 
It  does  not  appear  to  be  in  the  power  of  the  will,  Prof.  Wheatstone  remarks,  to 
determine  the  appearance  of  either ;  but,  if  one  picture  be  more  illuminated 
than  the  other,  it  will  be  seen  during  a  larger  portion  of  the  time. — Many  other 
curious  experiments  with  this  simple  instrument  are  related  by  Prof.  Wheatstone; 
and  they  all  go  to  confirm  the  general  conclusion,  that  the  combination  of  the 
dissimilar  images  furnished  by  the  two  eyes  is  a  mental  act,  resulting  from  an 
inherent  law  of  our  psychical  constitution;  and  that  our  perceptions  of  the 
solidity  and  projection  of  objects,  near  enough  to  be  seen  in  different  perspec- 
tive with  the  two  eyes,  result  from  this  cause.  In  regard  to  distant  objects, 
however,  the  difference  in  the  images  formed  by  the  two  eyes  is  so  slight  that 

Fig.  215. 


it  cannot  aid  in  the  determination ;  and  hence  it  is  that,  whilst  we  have  no 
difficulty  in  distinguishing  a  picture,  however  well  painted,  from  a  solid  object, 
when  placed  near  our  eyes  (since  the  idea  which  might  be  suggested  by  the 
image  formed  on  one  eye,  will  then  be  corrected  by  the  other),  we  are  very 
liable  to  be  misled  by  a  delineation  in  which  the  perspective,  light,  and  shade, 
&c.,  are  faithfully  depicted,  if  we  are  placed  at  a  distance  from  it,  and  are  pre- 
vented from  perceiving  that  it  is  but  a  picture.  In  this  case,  however,  a  slight 
movement  of  the  head  is  sufficient  to  undeceive  us ;  since  by  this  movement  a 
great  change  would  be  occasioned  in  the  perspective  view  of  the  object,  supposing 
it  to  possess  an  uneven  surface;  whilst  it  scarcely  affects  the  image  formed  by  a 
picture.  In  the  same  manner,  a  person  who  only  possesses  one  eye  obtains, 
by  a  slight  motion  of  his  head,  the  same  idea  of  the  form  of  body  which  another 
would  acquire  by  the  simultaneous  use  of  his  two  eyes. 

889.  The  appreciation  of  the  distance  of  objects  may  be  easily  shown  to  be 
principally  derived  from  the  association,  in  the  Mind,  of  visual  and  tactile  sen- 
sations; assisted,  in  regard  to  near  objects,  by  the  sensations  derived  from  the 
muscles  of  the  eyeballs.  How  much  our  right  estimation  of  the  relative  dis- 
tances of  objects  not  too  far  removed  from  the  eye  depends  upon  the  joint  use 


888  OF   SENSATION,   AND   THE   ORGANS   OP   THE    SENSES. 

of  both  eyes,  is  made  evident  by  the  fact  that,  if  we  close  one  eye,  we  find  our- 
selves unable  to  execute  with  certainty  many  actions  (such  as  threading  a  needle 
or  snuffing  a  candle)  which  require  its  guidance;  and  we  can  scarcely  conceive 
of  any  other  basis  for  this  appreciation  than  that  which  is  afforded  by  the  mus- 
cular sensations  produced  by  the  different  degrees  in  which  the  optic  axes  are 
made  to  converge,  according  to  the  distances  of  the  objects  to  which  we  direct 
our  eyes.  For,  in  proportion  as  they  are  removed  further  and  further,  do  the 
optic  axes  approach  parallelism,  and  the  power  of  appreciating  differences  of 
distance  is  lost;  whilst,  on  the  other  hand,  in  proportion  as  the  object  is  ap- 
proximated to  the  eyes,  slight  differences  of  distance  produce  marked  differences 
in  the  degree  of  convergence;  and  these  are  readily  appreciated,  so  as  to  afford 
the  means  of  very  nice  discrimination.  The  large  extent  to  which  our  notion 
of  the  relative  distances  of  near  objects  is  due  to  variations  in  the  angle  of  con- 
vergence of  the  optic  axes,  is  further  shown  by  the  following  experiment  devised 
by  Prof.  Wheatstone.  If  two  similar  pictures  be  placed  in  his  mirror-stereoscope, 
and  be  made  to  move  to  and  from  the  mirrors,  so  as  to  vary  their  distances  from 
these,  and  therefore  from  the  eyes,  without  altering  the  angle  of  convergence, 
their  apparent  sizes  are  seen  to  change  (in  consequence  of  the  alteration  of  the 
visual  angle),  but  no  positive  change  is  seen  in  their  apparent  distances ;  the 
effect  produced  being  very  much  like  that  of  the  enlargement  or  diminution  of 
the  images  on  the  screen  in  the  exhibition  of  the  Phantasmagoria,  suggesting  the 
idea  of  approach  or  recession,  although  we  perceive  that  the  distance  of  the 
screen  from  our  eyes  has  undergone  no  alteration.  A  converse  effect,  as  we 
shall  presently  see  (§  890),  is  produced  by  alterations  in  the  angle  of  converg- 
ence, without  any  real  change  in  the  distance  of  the  pictures.  This  power  of 
estimating  distance,  however  is  obviously,  in  Man,  not  an  intuitive  but  an  ac- 
quired endowment ;  for  it  is  evident  to  any  observer  that  infants,  or  older  per- 
sons who  have  but  recently  acquired  sight,  form  very  imperfect  ideas  respecting 
the  distance  of  objects,  their  attempts  to  grasp  bodies  which  attract  their  atten- 
tion being  for  a  long  time  unsuccessful ;  and  that  they  only  gradually  learn  to 
measure  distances  by  the  sight  through  the  medium  of  the  touch.  It  is  pro- 
bable, however,  that,  in  the  lower  Animals,  especially  such  as  have  early  to  rely 
upon  their  own  exertions  for  the  supply  of  their  natural  wants,  the  perception 
of  distance  is  more  intuitive  than  it  is  in  ourselves ;  since  we  may  observe  them 
very  early  performing  actions  which  require  an  exact  appreciation  of  it. — In 
regard  to  distant  objects,  our  judgment  is  chiefly  founded  upon  their  apparent  size, 
if  their  actual  size  be  known  to  us;  but,  if  this  be  not  the  case,  and  if  we  are  so 
situated  that  we  cannot  judge  of  the  intervening  space,  we  principally  form  our 
estimate  from  that  effect  of  different  degrees  of  remoteness  upon  the  distinctness 
of  their  color  and  outline,  which  is  known  to  artists  as  "  aerial  perspective." 
Hence  this  estimate  is  liable  to  be  greatly  affected  by  varying  states  of  the 
atmosphere,  as  is  particularly  known  to  every  one  who  has  visited  warmer  cli- 
mates; where  the  extreme  clearness  of  the  air  sometimes  brings  into  an  appa- 
rently near  proximity,  a  hill  that  rises  some  miles  beyond  a  neighboring  ridge 
(the  intervening  space  being  hidden,  so  as  not  to  afford  any  datum  for  the  esti- 
mate of  the  distance  of  the  remote  hill),  whilst  a  slight  haziness  carries  its  ap- 
parent distance  to  three  or  four  times  the  reality. 

890.  Our  estimate  of  the  size  of  an  object  is  partly  dependent  upon  the  visual 
angle  under  which  we  see  it,  and  partly  upon  our  estimate  of  its  distance.  The 
"  visual  angle,"  formed  by  imaginary  lines  drawn  from  the  eye  (Fig.  216,  A)  to 
the  extreme  points,  B  c,  of  the  object,  is  the  measure  of  the  size  of  its  image 
upon  the  retina ;  and  it  is  obvious  that,  if  two  objects,  B  c,  D  E,  the  former 
being  twice  the  length  of  the  latter,  be  placed  at  the  same  distance,  the  visual 
angle  B  A  c  being  twice  as  great  as  the  angle  DAE,  the  image  of  B  c  upon  the 
retina  will  be  twice  as  long  as  that  of  D  E,  and  the  mind  will  estimate  their 


SENSE   OF   VISION. 


889 


relative  sizes  accordingly.  But  if  the  distance  of  the  object  D  E  from  the  eye 
be  diminished  to  one-half,  so  that  it  is  brought  into  the  position  F  G,  its  visual 
angle,  and  consequently  the  size  of  its  image  on  the  retina,  will  now  be  equal 
to  that  of  B  c ;  and  the  estimate  we  form  of  the  relative  sizes  of  the  two  will 
entirely  depend  upon  the  idea  we  entertain  of  their  relative  distances.  Hence 
any  circumstance  which  modifies  that  idea  produces  a  corresponding  difference 


in  our  estimate  of  their  size;  so  that  the  apparent  size  of  an  object,  seen  under 
the  same  visual  angle,  may  be  estimated  as  larger  or  smaller  than  the  reality, 
according  as  we  suppose  it  to  be  more  or  less  distant  than  it  really  is.  Of  this 
we  have  a  familiar  instance  in  the  fact  that,  if  we  meet  a  child  whilst  we  are 
walking  across  a  common  (the  flatness  of  the  ground  not  giving  us  much  power 
of  estimating  the  intervening  space)  in  a  fog,  it  appears  to  have  the  stature  of  a 
man,  and  a  man  seems  like  a  giant ;  for  the  indistinctness  of  outline  causes  the 
mind  to  conceive  of  the  figures  as  at  a  greater  distance  than  they  really  are,  and 
their  apparent  dimensions  are  augmented  in  like  proportion.  For  if  the  object 
F  G  (Fig.  216)  be  mentally  carried  back  to  the  distance  of  D  E,  being  still  seen 
under  the  visual  angle  FAG  (or  B  A  c),  it  will  appear  to  possess  the  length 
B  c  instead  of  D  E.  On  the  other  hand,  if  the  object  B  c  were  to  be  mentally 
brought  forwards  into  the  position  K  L,  its  apparent  size  being  still  determined 
by  its  visual  angle,  it  will  seem  to  be  reduced  to  the  length  F  G.  This  has  been 
demonstrated  by  a  very  ingenious  experiment  devised  by  Prof.  Wheatstone. 
For  if  two  similar  pictures  placed  in  his  mirror-stereoscope,  be  made  so  to  change 
their  places  in  regard  to  the  mirrors  (by  moving  in  a  horizontal  circle  of  which 
the  middle  point  between  the  mirrors  is  the  centre),  that  the  angle  of  converg- 
ence of  the  optic  axis  is  increased,  whilst  the  actual  distance  of  the  pictures 
from  the  mirrors,  and  consequently  their  visual  angles,  remain  the  same,  their 
apparent  size  is  progressively  and  most  remarkably  diminished ;  the  mind  being 
accustomed  to  interpret  increase  of  the  angle  of  convergence  as  a  proof  of  dimi- 
nution of  distance,  and  being  thus  impressed  by  the  change  as  if  the  pictures 
had  really  advanced  to  K  L ;  and  as  they  are  still  seen  under  the  angle  BAG 
(or  F  A  G),  instead  of  under  the  angle  K  A  L,  their  dimensions  are  reduced  to 
the  mind's  eye  from  B  C  to  F  G.  A  very  simple  and  beautiful  illustration  of  the 
same  principle  is  furnished  by  the  ordinary  stereoscope,  when  two  pairs  of 
figures  (such  as  those  given  in  Fig.  215)  are  employed,  the  effect  of  one  of  which 


890      OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 

is  to  develop  a  projecting,  and  that  of  the  other  a  receding  surface.  For  it  will 
be  observed  that  the  relative  size  of  the  parts  which  appear  to  project  is  reduced, 
whilst  that  of  the  apparently  receding  parts  is  augmented  ;  as  is  particularly  the 
case  with  the  square  truncated  end  of  the  pyramid,  which  is  estimated  by  most 
persons  as  from  one-third  to  one-half  larger  in  each  of  its  dimensions  in  the 
receding,  than  it  is  in  the  projecting  pyramid,  notwithstanding  that  the  actual 
sizes  of  the  squares  in  the  two  sets  of  figures  are  precisely  the  same.  For,  sup- 
posing H  I  to  represent  the  real  side  of  one  of  the  small  squares,  which  becomes 
the  truncated  end  of  the  pyramid ;  when  this  is  brought  forward  by  the  mind 
into  the  position  K  L,  as  the  truncated  top  of  a  projecting  pyramid,  being  seen 
under  the  visual  angle  H  A  I,  its  apparent  size  is  reduced  to  F  G ;  whilst,  on  the 
other  hand,  the  very  same  square,  carried  back  by  the  mind  to  the  distance  I)  E, 
as  when  it  forms  the  truncated  end  of  the  receding  pyramid,  is  mentally  enlarged 
to  the  dimensions  B  c,  the  visual  angle  B  A  c  being  the  same  as  H  A  i. — It  is 
obvious,  from  what  has  been  stated  in  regard  to  distance,  that  our  power  of  form- 
ing a  true  estimate  of  the  relative  sizes  is  far  greater  with  regard  to  near  objects, 
whose  relative  distances  we  can  estimate  with  tolerable  accuracy,  than  it  is  with 
respect  to  more  remote  bodies,  whose  relative  distances  we  have  no  means  of 
appreciating ;  thus,  the  sun  and  the  moon  are  of  nearly  the  same  apparent  size 
to  us,  though  one  is  about  four  million  times  the  distance  of  the  other ;  and  we 
may  cover  either  disk  with  a  sixpence  held  near  the  eye,  so  as  to  be  seen  under 
the  same  visual  angle,  without  the  least  power  of  estimating  the  relative  sizes 
of  these  objects,  save  by  a  calculation  based  on  a  knowledge  of  their  relative 
distances,  because,  whilst  the  one  is  near,  the  other  is  virtually  almost  infinitely 
remote. — The  want  of  innate  power  in  Man  to  form  a  true  conception  of  either 
size  or  distance,  is  well  shown  by  the  effect  produced  on  the  mind  unprepared 
for  such  delusions,  by  a  skilfully  painted  picture ;  the  view  of  which  is  so  con- 
trived, that  its  distance  from  the  eye  cannot  be  estimated  in  the  ordinary  man- 
ner; for  the  objects  it  represents  are  invested  by  the  mind  with  their  real  sizes 
and  respective  distances,  as  if  their  real  images  were  formed  upon  the  retina.1 

891.  From  all  these  considerations,  we  are  led  to  perceive  the  truth  of  the 
quaint  observation  made  by  Dr.  Brown — that  "vision  is,  in  fact,  the  art  of 
seeing  things  which  are  invisible;"  that  is,  of  acquiring  information,  by  means 
of  the  eye,  which  is  neither  contained  in  the  sensations  of  sight  themselves, 
nor  logically  deducible  from  the  intimations  which  those  sensations  really  con- 
vey.    We  cannot  too  constantly  bear  in  mind,  in  treating  of  this  subject,  that 
we  do  not  take  cognizance  by  our  optic  nerves,  as  we  do  by  the  nerves  of  touch, 
of  material  bodies  themselves,  but  of  the  pictures  or  images  formed  by  those 
objects ;  and  whatever  be  the  notions  suggested  by  the  picture,  that  can  never 
be  transformed  into  anything  else.     These  notions  appear  to  be,  in  the  lower 
Animals,  entirely  of  an  intuitional  or  instinctive  character ;  in  Man  they  are  so 
in  a  much  less  degree ;  and  although  it  is  impossible  to  come  to  a  precise  con- 
clusion on  the  subject,  from  the  want  of  sufficient  data,  it  is  indubitable  that  a 
large  part  of  the  knowledge  of  the  external  world,  which  he  derives  in  the  adult 
condition  from  the  use  of  his  eyes  alone,  is  really  dependent  upon  the  early 
education  of  his  perceptive  powers,  in  which  process,  the  sensations  conveyed  by 
different  organs  are  brought  into  relation  with  one  another. 

892.  The  persistence,  during  a  certain  interval,  of  impressions  made  upon 
the  retina,  gives  rise  to  a  number  of  curious  visual  phenomena.     The  prolonga- 
tion of  the  impression  will  be  governed,  in  part,  by  its  previous  duration.     Thus, 
when  we  rapidly  move  an  ignited  point  through  a  circle,  the  impression  itself 

1  This  delusion  has  been  extremely  complete  in  some  of  those  who  have  seen  the  pano- 
ramic view  of  London  in  the  Coliseum.  A  lively  and  interesting  account  of  it  is  given  in 
the  "Journal  of  the  Parsee  Shipbuilders,"  who  visited  England  some  time  ago. 


SENSE   OF  VISION.  891 

is  momentary,  and  remains  but  for  a  short  time ;  whilst,  if  we  have  been  for 
some  time  looking  at  a  window,  and  then  close  our  eyes,  the  impression  of  the 
dark  bars  traversing  the  illuminated  space  is  preserved  for  several  seconds. 
Such  phenomena  can  here  be  only  briefly  adverted  to.  One  of  these  is  the 
combination,  into  a  single  image,  of  two  or  more  objects  presented  to  the  eye  in 
successive  movements;  but  these  must  be  of  a  kind  which  can  be  united,  other- 
wise a  confused  picture  is  produced.  Thus  in  a  little  toy,  called  the  Thauma- 
trope,  which  was  introduced  some  years  ago,  the  two  objects  were  painted  on 
the  opposite  sides  of  a  card — a  bird,  for  instance,  on  one,  and  a  cage  on  the 
other;  and,  when  the  card  was  made  (by  twisting  a  pair  of  strings)  to  revolve 
about  one  of  its  diameters,  in  such  a  manner  as  to  be  alternately  presenting  the 
two  sides  to  the  eye  at  minute  intervals,  the  two  pictures  were  blended,  the 
bird  being  seen  in  the  cage.  A  far  more  curious  illusion,  however,  was  that 
first  brought  into  notice  by  Prof.  Faraday;  who  showed  that,  if  two  toothed 
wheels,  placed  one  behind  the  other,  be  made  to  revolve  with  equal  velocity,  a 
stationary  spectrum  will  be  seen ;  whilst,  if  one  be  made  to  revolve  more  rapidly 
than  the  other,  or  the  number  of  teeth  be  different,  the  spectrum  also  will 
revolve.  The  same  takes  place  when  a  single  wheel  is  made  to  revolve  before  a 
mirror,  the  wheel  and  its  image  answering  the  purpose  of  the  two  wheels  in  the 
former  case.  On  this  principle,  a  number  of  very  ingenious  toys  have  been 
constructed;  in  some  of  these,  the  same  figure  or  object  is  seen  in  a  variety  of 
positions ;  and  the  successive  impressions,  passing  rapidly  before  the  eye,  give 
rise  by  their  combination  to  the  idea  that  the  object  is  itself  moving  through 
these  positions.1  It  is  interesting  to  remark,  moreover,  that  when  the  eye  has 
been  for  some  time  contemplating  an  object  in  motion,  and  is  then  directed 
towards  stationary  objects,  these  appear  for  a  short  time  to  have  a  like  movement. 
Any  railroad  traveller  may  try  this  simple  experiment,  by  first  looking  at  the 
hedges,  &c.,  which  he  is  rapidly  passing,  and  then  at  some  part  of  the  interior 
of  the  carriage  itself,  especially  one  which  presents  a  series  of  parallel  lines. 
But  when  the  impression  of  movement  has  been  of  longer  duration,  its  effects 
upon  the  retina  are  less  transient ;  thus  a  person  who  has  been  for  some  time 
on  board  ship,  sees  the  floors,  walls,  and  ceilings  of  his  apartment  on  shore 
in  a  state  of  continual  up-and-down  motion,  even  for  some  days  after  he  has 
landed. 

893.  When  the  Retina  has  been  exposed  for  some  time  to  a  strong  impres- 
sion of  some  particular  kind,  it  seems  less  susceptible  of  feebler  impressions  of 
the  same  kind.  Thus,  if  we  look  at  any  brightly  luminous  object,  and  then 
turn  our  eyes  on  a  sheet  of  white  paper,  we  shall  perceive  a  dark  spot  upon  it ; 
the  portion  of  the  retina,  which  had  been  affected  by  the  bright  image,  not 
being  able  to  receive  an  impression  from  the  fainter  rays  reflected  by  the  paper. 
The  dark  spectrum  does  not  at  once  disappear,  but  assumes  different  colors  in 
succession — these  being  expressions  of  the  states  through  which  the  retina 
passes,  in  its  transition  to  the  natural  condition.  If  the  eye  has  received  a 
strong  impression  from  a  colored  object,  the  spectrum  exhibits  the  complement- 
ary color  ;a  thus,  if  the  eye  be  fixed  for  any  length  of  time  upon  a  bright  red 

1  A  very  beautiful  "  philosophical  toy"  was  shown  to  the  Author  some  years  since,  by  its 
inventor,  Mr.  Roberts,  the  celebrated  machinist  of  Manchester ;  consisting  in  an  apparatus 
by  which  it  was  made  possible  to  read  words  printed  on  a  card,  although  the  card  itself 
was  made  to  revolve  on  its  axis  even  30,000  times  in  a  minute.     The  principle  of  its  con- 
struction was  simply  this — that  the  eye  caught  a  succession  of  glimpses  of  the  card, 
through  a  narrow  slit  before  which  a  disk  with  a  single  corresponding  perforation  was 
made  to  revolve;  the  rate  of  movement  of  this  disk  being  so  adjusted  to  that  of  the  card, 
that,  whenever  the  eye  caught  sight  of  the  latter,  it  was  momentarily  in  the  same  position, 
so  that,  by  the  succession  of  transient  impressions  thus  made  upon  the  retina,  the  words 
printed  on  the  card  could  be  distinctly  read. 

2  By  the  "complementary"  color  is  meant  that  which  would  be  required  to  make  white 


892  OP   SENSATION,    AND   THE   ORGANS   OP   THE    SENSES. 

spot  on  a  white  ground,  and  be  then  suddenly  turned  so  as  to  rest  upon  the  white 
surface,  we  see  a  spectrum  of  a  green  color.  The  same  explanation  applies  to  the 
curious  phenomenon  of  colored  shadows.  It  may  not  unfrequently  be  observed 
at  sunset,  that  when  the  light  of  the  sun  acquires  a  bright  orange  color  from  the 
clouds  through  which  it  passes,  the  shadows  cast  by  it  have  a  blue  tint.  Again, 
in  a  room  with  red  curtains,  the  light  which  passes  through  these  produces  green 
shadows.  In  both  instances,  a  strong  impression  of  one  color  is  made  on  the 
general  surface  of  the  retina;  and  at  any  particular  spots,  therefore,  at  which 
the  light  is  colorless  but  very  faint,  that  color  is  not  perceived,  its  complement 
only  being  visible.  The  correctness  of  this  explanation  is  proved  by  the  fact 
that,  if  the  shadow  be  viewed  through  a  tube,  in  such  a  manner  that  the 
colored  ground  is  excluded,  it  seems  like  an  ordinary  shadow.  It  is  not  unlikely 
that,  as  Mliller  suggests,  the  predominant  action  of  one  color  on  the  retina 
disturbs  (as  it  were)  the  equilibrium  of  its  condition,  and  excites  in  it  a  tend- 
ency to  the  development  of  a  state  corresponding  to  that  which  is  produced  by 
the  impression  of  the  complementary  color;  for  the  latter  is  perceived,  according 
to  him,  even  where  it  does  not  exist,  as  when  the  eye,  after  receiving  a  strong 
impression  from  a  colored  spot,  and  directed  upon  a  completely  dark  surface 
or  into  a  dark  cavity,  still  perceives  the  spectrum.  This  change,  indeed,  extends 
beyond  the  spot  on  which  the  impression  is  made;  for,  as  is  well  known  to 
Artists,  the  sensory  impression  produced  by  any  color  is  greatly  affected  by 
neighboring  hues.  Thus,  if  four  strips  of  colored  paper,  or  any  other  fabric, 
A,  B,  c,  D — two  of  them,  A,  B,  of  one  color  (e.  g.  red),  and  the  other  two,  c,  D, 
of  some  different  color  (e.  g.  blue) — be  laid  side  by  side  at  intervals  of  about 
half  an  inch,  the  hues  of  the  two  central  strips  B,  c,  will  be  decidedly  modified 
by  each  other's  proximity,  each  approximating  to  the  hue  of  the  complement- 
ary color  of  the  other;  so  that,  instead  of 

A  B  CD 

red  red      .  blue  blue, 

we  shall  see 

A  B  CD 

red  orange  red  greenish  blue  blue. 

— Upon  these  properties  of  the  eye  are  founded  the  laws  of  harmonious  color- 
ing, which  have  an  obvious  analogy  with  those  of  musical  harmony.  All  com- 
plementary colors  have  an  agreeable  effect,  when  judiciously  disposed  in 
combination ;  and  all  bright  colors,  which  are  not  complementary,  have  a  dis- 
agreeable effect,  if  they  are  predominant :  this  is  especially  the  case  in  regard  to 
the  simple  colors,  strong  combinations  of  any  two  of  which,  without  any  color 
that  is  complementary  to  either  of  them,  are  extremely  offensive.  Painters 
who  are  ignorant  of  these  laws,  introduce  a  large  quantity  of  dull  gray  into 
their  pictures,  in  order  to  diminish  the  glaring  effects  which  they  would  other- 
wise produce;  but  this  benefit  is  obtained  by  a  sacrifice  of  the  vividness  and  force, 
which  may  be  secured  in  combination  with  the  richest  harmony,  by  a  proper 
attention  to  physiological  principles. 

894.  Some  persons,  who  can  perfectly  distinguish  forms,  are  deficient,  through 
some  original  peculiarity  in  the  constitution  of  the  retina,  in  the  power  of  dis- 
criminating colors.  This  is  most  commonly  seen  in  regard  to  the  complementary 
colors,  especially  red  and  green;  such  persons  not  being  able  to  perceive  cherries 

or  colorless  light,  when  mixed  with  the  original.  As  red,  blue,  and  yellow  are  the  primary 
or  elementary  colors,  red  is  the  complement  of  green  (which  is  composed  of  yellow  and 
blue] ;  blue  is  the  complement  of  orange  (red  and  yellow) ;  and  yellow  of  purple  (red  and 
blue) ;  and  vice  versa  in  all  instances. 


SENSE   OF   VISION. 

amidst  the  leaves  on  a  tree,  except  by  the  difference  of  their  form.  Several 
distinct  varieties  of  this  affection  may  be  distinguished,  however;  these  have 
been  classified  by  Seebeck  and  Wartmann.1 

895.  Amongst  other  curious  phenomena  of  Vision,  is  the  vanishing  of  images 
which  fall  at  the  entrance  of  the  optic  nerve;  as  is  shown  in  the  following  ex- 
periment.    Let  two  black  spots  be  made  upon  a  piece  of  paper,  about  four  or 
five  inches  apart ;  then  let  the  left  eye  be  closed,  and  the  right  eye  be  strongly 
fixed  upon  the  left  hand  spot.     If  the  paper  be  then  moved  backwards  and  for- 
wards, so  as  to  change  its  distance  from  the  eye,  a  point  will  be  found  at  which 
the  right  hand  spot  is  no  longer  visible;  though  it  is  clearly  seen  when  the  paper 
is  brought  nearer  or  removed  further.     In  this  position  of  the  eye  and  object, 
the  rays  from  the  right  hand  spot  cross  to  the  nasal  side  of  the  globe,  and  fall 
upon  the  point  of  the  retina  which  has  just  been  mentioned.     The  phenomenon 
is  not  confined  to  that  spot,  however;  nor  is  it  correct  to  say,  as  is  sometimes 
done,  that  the  retina  is  not  sensible  to  light  at  that  point;  since,  if  such  were 
the  case,  we  should  see  a  dark  spot  in  our  field  of  view  whenever  we  use  only 
one  eye.     The  fact  is,  that  a  similar  phenomenon  may  occur  under  somewhat 
different  conditions,  in  any  division  of  the  retina,  especially  in  its  lateral  parts. 
Thus,  if  we  fix  the  eye  for  some  time,  until  it  is  fatigued,  upon  a  strip  of  colored 
paper  lying  upon  a  white  surface,  the  image  of  the  colored  object  will  in  a  short 
time  disappear,  and  the  white  surface  will  be  seen  in  its  place;  the  disappear- 
ance of  the  image,  however,  is  only  of  a  few  seconds'  duration.     The  truth  seems 
to  be,  that  there  is  a  tendency  in  the  retina  to  the  propagation,  over  neighbor- 
ing parts,  of  impressions  which  occupy  a  large  proportion  of  its  surface;  and 
that  this  tendency  is  the  strongest  around  the  point  at  which  the  optic  nerve 
enters,  so  that  the  state  of  this  part  will  generally  become  similar  to  that  of  the 
surrounding  portion  of  the  retina.     Hence,  when  we  are  using  one  eye  only,  we 
do  not  perceive  any  dark  spot  in  the  field,  but  only  a  certain  degree  of  indis- 
tinctness in  a  portion  of  the  image. 

896.  Under  particular  circumstances,  we  may  receive  a  visual  representation 
of  the  retina  itself,  as  is  shown  by  the  experiment  of  Purkinje.     "  If  in  a  room 
otherwise  dark,  a  lighted  candle  be  moved  to  and  fro,  or  in  a  circle,  at  a  distance 
of  six  inches  before  the  eyes,  we  perceive,  after  a  short  time,  a  dark  arborescent 
figure  ramifying  over  the  whole  field  of  vision;  this  appearance  is  produced  by 
the  vasa  centralia  distributed  over  the  retina,  or  by  the  parts  of  the  retina 
covered  by  those  vessels.     There  are,  properly  speaking,  two  arborescent  figures, 
the  trunks  of  which  are  not  coincident,  but  on  the  contrary  arise  in  the  right 
and  left  divisions  of  the  field,  and  immediately  take  opposite  directions.     One 
trunk  belongs  to  each  eye,  but  their  branches  intersect  each  other  in  the  com- 
mon field  of  vision.     The  explanation  of  this  phenomenon  is  as  follows  :  By 
the  movement  of  the  candle  to  and  fro,  the  light  is  made  to  act  on  the  whole 
extent  of  the  retina,  and  all  the  parts  of  the  membrane  which  are  not  immedi- 
ately covered  by  the  vasa  centralia  are  feebly  illuminated ;  those  parts,  on  the 
contrary,  which  are  covered  with  those  vessels  cannot  be  acted  on  by  the  light, 
and  are  perceived,  therefore,  as  dark  arborescent  figures.     These  figures  appear 
to  lie  before  the  eye,  and  to  be  suspended  in  the  field  of  vision/'2     We  have 
thus  another  demonstration  of  the  fact  that,  in  ordinary  vision,  the  immediate 
object  of  our  sensation  is  a  certain  condition  of  the  retina,  which  is  excited  by 
the  formation  of  a  luminous  image. 

'    Muller's  "Elements  of  Physiology"  (Baly's   Translation),  p.  1213;    and  Taylor's 
"Scientific  Memoirs,"  vol.  iv.  p.  156,  et  seq. 
2  Muller's  "Elements  of  Physiology"  (Baly's  Translation),  p.  1163. 


894  OF   SENSATION,    AND   THE   ORGANS    OF   THE   SENSES 


6. — Sense  of  Hearing. 

897.  In  the  Ear,  as  in  the  Eye,  the  impressions  made  upon  the  sensory  nerve 
are  not  at  once  produced  by  the  body  which  originates  the  sensation  ;  but  they 
are  propagated  to  it  through  a  medium  capable  of  transmitting  them.     Here 
too,  therefore,  we  take  cognizance  by  the  mind,  not  of  the  sonorous  object,  but 
of  the  condition  of  the  auditory  nerve;  and  all  the  ideas  we  form  of  sounds,  as 
to  their  nature,  intensity,  direction,  &c.,  must  be  based  upon  the  changes  which 
they  produce  in  it.     The  complex  contrivances  which  we  meet  with  in  the  organ 
of  Hearing  among  higher  animals,  are  evidently  intended  to  give  them  greater 
power  of  discriminating  sounds,  than  is  possessed  by  the  lower  tribes ;  in  which 
last  it  is  reduced  to  a  form  so  simple,  that  it  may  be  questioned  whether  they 
can  be  said  to  possess  an  organ  of  hearing,  if  by  this  term  we  imply  anything 
more  than  the  mere  consciousness  of  sonorous  vibrations. — There  is  a  consider- 
able difference,  however,  between  the  Eye  and  the  Ear,  in  regard  to  the  special 
purposes  for  which  they  are  respectively  adapted.     In  the  former  we  have  seen, 
that  the  whole  object  of  the  instrument  is  to  direct  the  rays  of  light  received 
by  it,  in  such  a  manner  as  to  occasion  them  to  fall  upon  the  expansion  of  the 
optic  nerve  in  similar  relative  positions,  and  with  corresponding  proportional 
intensities,  to  those  which  they  possessed  when  issuing  from  the  object.     We 
have  no  reason  to  believe  anything  of  this  kind  to  be  the  purpose  of  the  Ear; 
indeed,  it  would  be  inconsistent  with   the  laws  of  the  propagation  of  sound. 
Sonorous  vibrations  having  the  most  various  directions,  and  the  most  unequal 
rates  of  succession,  are  transmitted  by  all  media  without  modification,  however 
numerous  their  lines  of  intersection  ;  and  wherever  these  undulations  fall  upon 
the  auditory  nerve,  they  must  cause  the  sensation  of  corresponding  sounds.     Still 
it  is  probable  that  some  portions  of  the  complex  organ  of  hearing,  in  Man  and 
in  the  higher  animals,  are  more  adapted  than  others  to  receive  impressions  of  a 
particular  character;  and  that  thus  we  may  be  especially  informed  of  the  direc- 
tion of  a  sound  by  one  part  of  the  organ,  of  its  musical  tone  by  another,  and  of 
some  other  of  its  qualities  by  a  third. 

898.  The  essential  part  of  an  Organ  of  Hearing  is  obviously  a  nerve,  endowed 
with  the  peculiar  property  of  receiving  sonorous  undulations,  and  of  transmitting 
their  effects  to  the  Sensorium.     This  nerve  is  spread  out  over  the  surface  of  a 
delicate  membrane  which  lines  the  Vestibule  and  its  prolongations ;  and  this 
membrane  incloses  a  fluid  which  is  the  medium  whereby  the  sonorous  vibra- 
tions received  through  the  external  ear  are  communicated  to  the  nerve.     We 
learn  from  an  examination  of  the  comparative  structure  of  the  auditory  appara- 
tus in  the  lower  animals,  and  from  the  study  of  its  development  in  the  higher, 
that  the  part  which,  being  most  constantly  present  and  being  also  the  earliest 
in  its  development,  may  be  considered  as  the  most  essential,  is  the  simple  Vesti- 
bular  cavity,  which   exists  where  there   are  no  vestiges  either  of  Semicircular 
Canals,  of  Cochlea,  or  of  Tympanic  apparatus.     Such  a  condition  presents  itself 
in  some  of  the  higher  Invertebrata  and  in  the  lowest  Fishes ;  but  as  we  ascend 
the  Vertebrated  series,  we  find  the  semicircular  canals  growing  out  (as  it  were) 
of  the  Vestibule  in  Fishes,  a  tympanic  apparatus  superadded  in  Reptiles,  and  a 
Cochlea  first  acquiring  a  more  than  rudimentary  development  in  the  class  of 
Birds,  although  only  presenting  in    Mammalia  that  characteristic  form  from 
which  it  derives  its  name.1     Of  the  mode  in  which  the  ultimate  subdivisions  of 
the  Auditory  nerve  are  distributed  upon  the  lining  membrane  of  the  labyrinth, 
it  does  not  yet  seem  possible  to  give  a  certain  account ;  for  although  Wagner 

1  For  a  more  detailed  sketch  of  the  Comparative  Anatomy  of  the  Organ  of  Hearing,  see 
the  Author's  "  Princ.  of  Physiol.,  Gen.  and  Comp.,"  \\  822-825,  Am.  Ed. 


SENSE   OF    HEARING 


895 


and  others  have  represented  them  as  terminating  in  free  loops,  yet  more  care- 
ful observation  has  rendered  this  doubtful ;  and  the  general  analogy  between 
the  simpler  forms  of  the  auditory  and  of  the  visual  apparatus,  as  well  as  the 

Fig.  217. 


General  view  of  the  external,  middle,  and  internal  Ear,  as  seen  in  a  prepared  section  through  a,  the  auditory 
canal,  b.  The  tympanum  or  middle  ear.  c.  Eustachian  tube,  leading  to  the  pharynx,  d.  Cochlea;  and  e- 
Semicircular  canals  and  vestibule,  seen  on  their  exterior,  as  brought  into  view  by  dissecting  away  the  sur- 
rounding petrous  bone.  The  styloid  process  projects  below;  and  the  inner  surface  of  the  carotid  canal  is  seen 
above  the  Eustachian  tube.  From  Scarpa. 

close  correspondence  which  exists  between  them  in  the  history  of  their  develop- 
ment (the  organ  of  hearing,  like  the  eye,  being  budded  off  from  its  sensory  gan- 
glion), seems  to  indicate  that  the  peripheral  expansion  of  the  auditory  nerve  might 

Fig.  218. 


The  Auditory  Nerve  taken  out  of  the  Cochlea :  1, 1, 1,  the  trunk  of  the  nerve ;  2,  2,  Its  filaments  In  the  zona 
v  ossea  of  the  lamina  spiralis  ;  3,  3,  its  anastomoses  in  the  zona  vesicularis. 

be  expected  to  have  a  structure  analogous  to  that  of  the  retina.    The  most  exact 
observations  yet  made  on  this  point   seem  to  be  those  of  the  Marquis  Corti  on 


896  OF    SENSATION,    AND   THE    ORGANS   OP   THE   SENSES. 

the  Cochlear  nerve.1  This  nerve  passes  out  from  the  modwlus  into  a  series  of 
anastomosing  canals  excavated  in  the  osseous  lamina  spiralis;  and  it  there 
comes  into  relation  with  a  band  of  vesicular  substance,  which  lies  near  the  edge 
of  the  lamina  along  its  whole  length.  The  component  vesicles  are  elongated, 

Fig.  219. 


A  highly  magnified  view  of  a  small  piece  of  the  Lamina  Spiralis,  showing  the  manner  in  which  the  nerves 
leave  their  Neurilemma  as  they  anastomose;  the  natural  size  of  the  piece  is  seen  on  the  side  of  the  figure;  1, 
portion  of  the  auditory  nerve ;  2,  2,  osseous  canals  in  the  zona  ossea  of  the  lamina  spiralis ;  3,  3,  anastomoses 
in  the  zona  mollis ;  4,  4,  the  neurilemma  leaving  the  nervous  loops,  and  interlocking  to  form  the  layer  of  the 
zona  memhranacea. 

having  a  central  and  a  peripheral  extremity ;  by  the  former  they  are  connected 
with  the  fibres  of  the  cochlear  nerve,  the  connecting  filaments  being  destitute  (as 
elsewhere)  of  the  double  contour,  and  being  very  fragile ;  and  by  the  latter  they  are 
similarly  connected  with  the  fibres  which  issue  forth  from  the  osseous  lamina,  to 
be  distributed  upon  its  membranous  continuation.  These  fibres  form  fasciculi, 
which  traverse  the  membranous  lamina  nearly  parallel  to  each  other,  and  anas- 
tomose continually  with  one  another,  in  such  a  manner  as  to  present  the  appear- 
ance of  looped  terminations.  According  to  Corti,  however,  the  fibres  really 
pass  on  further,  losing  their  double  contour,  and  becoming  gradually  incorpo- 
rated, as  it  were,  with  the  surrounding  tissue.3 

899.  In  order  to  gain  any  definite  idea  of  the  uses  of  different  parts  of  the 
Ear,  it  is  necessary  to  bear  in  mind,  that  sounds  may  be  propagated  amongst 
solid  or  fluid  bodies  in  three  ways :  by  reciprocation,  by  resonance,  and  by  con- 
duction.— 1.  Vibrations  of  reciprocation  are  excited  in  a  sounding  body,  when 
it  is  capable  of  yielding  a  musical  tone  of  definite  pitch,  and  another  body  of 
the  same  pitch  is  made  to  sound  near  it.  Thus  if  two  strings  of  the  same  length 
and  tension  be  placed  along-side  of  each  other,  and  one  of  them  be  sounded  with 
a  violin  bow,  the  other  will  be  thrown  into  reciprocal  vibration ;  or  if  the  same 
tone  be  produced  near  the  string  in  any  other  manner,  as  by  a  flute  or  a  tuning- 
fork,  the  same  effect  will  result. — 2.  Vibrations  of  resonance  are  of  somewhat 
the  same  character ;  but  they  occur  when  a  sounding  body  is  placed  in  connec- 
tion with  any  other,  of  which  one  or  more  parts  may  be  thrown  into  reciprocal 
vibration,  even  though  the  tone  of  the  whole  be  different,  or  it  be  not  capable 

1  See  Kolliker  and  Siebold's  "Zeitschrift  fur  Wissenschaftliche  Zoologie,"  1851,  band 
iii.  heft  1. 

2  Such,  also,  is  the  account  of  their  termination  given  by  Messrs.  Todd  and  Bowman, 
"  Physiological  Anatomy,"  p.  467,  Am.  Ed. 


SENSE   OF   HEARING.  897 

of  producing  a  definite  tone  at  all.  This  is  the  case,  for  example,  when  a  tun- 
ing-fork in  vibration  is  placed  upon  a  sound-board ;  for,  even  though  the  whole 
board  have  no  definite  fundamental  note,1  it  will  divide  itself  into  a  number  of 
parts,  which  will  reciprocate  the  original  sound,  so  as  greatly  to  increase  its 
intensity ;  and  the  same  sound-board  will  act  equally  well  for  tuning-forks  of 
several  different  degrees  of  pitch.  When  a  smaller  body  is  used  for  resonance, 
however,  it  is  essential  that  there  should  be  a  relation  between  its  fundamental 
note  and  that  of  the  sonorous  body ;  otherwise,  no  distinct  resonance  is  pro- 
duced. Thus,  if  a  tuning-fork  in  vibration  be  held  over  a  column  of  air  in  a 
tube  of  such  a  length  that  the  same  note  would  be  given  by  its  vibration,  its 
sound  will  be  reciprocated.  And  if  it  be  held  over  a  pipe,  the  column  of  air 
in  which  is  a  multiple  of  this,  the  column  will  divide  itself  into  that  number  of 
shorter  parts,  each  of  which  will  reciprocate  the  original  sound,  and  the  total 
action  will  be  one  of  resonance.  But  if  the  length  of  the  pipe  bear  no  such 
correspondence  with  the  note  sounded  by  the  tuning-fork,  no  resonance  is  given 
by  the  column  of  air  it  contains. — 3.  Vibrations  of  conduction  are  the  only 
ones  by  which  sounds  can  strictly  be  said  to  be  propagated.  These  are  distin- 
guishable into  various  kinds,  into  which  it  is  not  requisite  here  to  inquire.  It 
should  be  remarked,  however,  that  all  media,  fluid,  liquid,  or  solid,  are  capable 
of  transmitting  sound  in  this  manner ;  a  vacuum  being  the  only  space  through 
which  it  cannot  pass.  The  transmission  is  usually  much  more  rapid  through 
solid  bodies  than  through  liquid;  and  through  liquid  than  through  gaseous. 
The  greatest  diminution  in  the  intensity  of  sound  is  usually  perceived,  when  a 
change  takes  place  in  the  medium  through  which  it  is  propagated,  especially 
from  the  aeriform  to  the  liquid. 

900.  The  detailed  application  of  these  principles  has  been  most  elaborately 
worked  out  by  Miiller  ;  and  the  following  statement  of  what  may  be  regarded 
as  the  present  condition  of  our  knowledge  of  the  subject  is  little  more  than  an 
abstract  of  his  results.  Considering  it  desirable,  in  the  first  place,  to  establish 
the  conditions  under  which  those  animals  hear,  that  are  constantly  immersed  in 
water,  he  made  a  series  of  experiments,  from  which  he  draws  the  following  con- 
clusions :  I.  Sonorous  vibrations,  excited  in  water,  are  imparted  with  consider- 
able intensity  to  solid  bodies. — n.  Sonorous  vibrations  of  solid  bodies  are  com- 
municated with  greater  intensity  to  other  solid  bodies  brought  in  contact  with 
them,  than  to  water ;  but  with  much  greater  intensity  to  water  than  to  atmo- 
spheric air. — in.  Sonorous  vibrations  are  communicated  from  air  to  water  with 
great  difficulty,  this  difficulty  very  much  exceeding  that  with  which  they  are 
propagated  from  one  part  of  the  air  to  another ;  but  their  transition  from  air 
to  water  is  much  facilitated  by  the  intervention  of  a  membrane  extended  be- 
tween them. — iv.  Sonorous  vibrations  are  not  only  imparted  from  water  to  solid 
bodies  with  definite  surfaces  which  are  in  contact  with  the  water,  but  are  also 
returned  with  increased  intensity  by  these  bodies  to  the  water;  so  that  the 
sound  is  heard  loudly  in  the  vicinity  of  those  bodies,  in  situations  where,  if  it 
had  its  origin  in  the  conducting  power  of  the  water  alone,  it  would  be  faint. — 

1  The  fundamental  note  of  a  body  is  the  lowest  tone  which  it  will  yield,  when  the  whole 
of  it  is  in  vibration  together.  By  dividing  the  body  into  two  or  more  distinct  parts,  it 
may  be  made  to  give  a  great  variety  of  sounds.  Thus,  if  a  stretched  string  be  divided  by 
a  bridge  into  two  equal  parts,  each  will  sound  the  octave  of  the  fundamental  note,  or  the 
8th  note  above  it.  If  it  be  divided  into  three  parts,  each  will  give  the  12th  above  the 
fundamental  note  ;  if  into  four,  the  15th  or  double  octave  will  be  heard  ;  if  into  five,  the 
17th  ;  if  into  six,  the  19th ;  if  into  seven,  the  20£th  (flat  seventh  above  the  second  octave) ; 
if  into  eight,  the  22d  or  triple  octave.  A  string  forcibly  set  in  vibration  has  a  tendency 
to  sound  these  harmonics  with  the  fundamental  note,  by  spontaneous  division  into  several 
distinct  segments  of  vibration ;  as  may  be  easily  made  evident,  by  striking  one  of  the 
lower  keys  of  the  piano,  and  listening  to  the  sounds  heard  whilst  the  fundamental  note  is 
dying  away. 

57 


OP  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 

V.  Sonorous  undulations,  propagated  through  water,  are  partially  reflected  by 
the  surfaces  of  solid  bodies. — vi.  Thin  membranes  conduct  sound  in  water 
without  any  loss  of  its  intensity,  whether  they  be  tense  or  lax. — From  in., 
IV.,  and  vi.,  we  learn  the  mode  in  which  the  sound  is  conducted  to  the  ear,  in 
aquatic  animals  not  breathing  atmospheric  air.  The  labyrinth  of  such  is 
either  entirely  inclosed  within  the  bones  of  the  head,  as  in  the  Cephalopoda,  and 
in  the  Cyclostome  and  Osseous  Fishes ;  or,  its  cavity  being  prolonged  to  the 
surface  of  the  body,  it  is  there  brought  into  communication  with  the  conducting 
medium,  by  means  of  a  membrane,  besides  receiving  the  vibrations  through 
the 'medium  of  the  solids  of  the  body,  as  is  the  case  in  Cartilaginous  Fishes 
and  Crustacea.  It  would  seem  as  if,  in  the  Osseous  Fishes,  the  resonance  of 
the  cranial  bones,  in  which  the  labyrinth  is  imbedded,  were  sufficient  to  give  the 
requisite  increase  of  intensity  to  the  sound ;  whilst  in  the  Cartilaginous  orders, 
the  softness  of  these  bones  renders  some  other  means  necessary.  In  addition 
to  this,  we  find  in  many  Fishes,  a  communication  with  the  air-bladder ;  which 
indeed  seems  to  have,  in  these,  but  little  other  use.  The  mode  in  which  this 
increases  by  resonance  the  intensity  of  the  sounds  will  appear  from  the  follow- 
ing experimental  conclusions. — VII.  When  sonorous  vibrations  are  communi- 
cated from  water,  to  air  inclosed  in  membranes  or  solid  bodies,  a  considerable 
increase  in  the  intensity  of  the  sound  is  produced  by  the  resonance  of  the  air 
thus  circumscribed. — vm.  A  body  of  air  inclosed  in  a  membrane,  and  sur- 
rounded by  water,  also  increases  the  intensity  of  the  sound  by  resonance,  when 
the  sonorous  undulations  are  communicated  to  it  by  a  solid  body. — From  these 
observations  it  may  be  concluded  that  the  air-bladder  of  Fishes,  in  addition  to 
other  uses,  serves  the  purpose  of  increasing  by  resonance  the  intensity  of  the 
sonorous  undulations  communicated  from  the  water  to  the  body  of  the  Fish. 
Moreover,  as  the  conducting  and  resonant  power  of  the  air  in  the  air-bladder  is 
greater  in  proportion  to  its  density,  the  influence  of  this  organ  on  the  percep- 
tion of  sounds  will,  of  course,  be  greater  in  deep  waters,  where  the  pressure 
upon  it  is  considerably  increased. 

901.  Most  animals  living  in  air  are  provided  with  an  opening  into  the  Vesti- 
bule, covered  by  a  thin  membrane ;  and,  in  the  majority  of  cases,  with  a  Tym- 
panic apparatus  also.  The  following  experimental  results  bear  upon  the  man- 
ner in  which  the  Ear  of  such  animals  is  affected  by  sound. — ix.  Sonorous 
undulations,  in  passing  from  air  directly  into  water,  suffer  a  considerable  dimi- 
nution in  their  strength;  while,  on  the  contrary,  if  a  tense  membrane  exist 
between  the  air  and  the  water,  the  sonorous  undulations  are  communicated  from 
the  former  to  the  latter  medium  with  great  intensity. — x.  The  sonorous  vibra- 
tions are  also  communicated,  without  any  perceptible  loss  of  intensity,  from  the 
air  to  the  water ;  when,  to  the  membrane  forming  the  medium  of  communica- 
tion, there  is  attached  a  short  solid  body,  which  occupies  the  greater  part  of  its 
surface,  and  is  alone  in  contact  with  the  water. — xi.  A  small  solid  body,  fixed 
in  an  opening  by  means  of  a  border  of  membrane,  so  as  to  be  movable,  commu- 
nicates sonorous  vibrations,  from  air  on  one  side,  to  water  or  the  fluid  of  the 
labyrinth  on  the  other,  much  better  than  solid  media  not  so  constructed.  But 
the  propagation  of  sound  to  the  fluid  is  rendered  much  more  perfect,  if  the 
solid  conductor,  thus  occupying  the  opening,  is  by  its  other  end  fixed  to  the 
middle  of  the  tense  membrane,  which  has  atmospheric  air  on  both  sides. — The 
fact  stated  in  ix.  is  evidently  one  of  great  importance  in  the  physiology  of 
hearing ;  and  fully  explains  the  nature  of  the  process  in  those  animals  which 
receive  the  sonorous  vibrations  through  air,  but  which  have  no  tympanic  appa- 
ratus. In  X.  we  have  the  elucidation  of  the  action  of  the  fenestra  ovalis,  and 
of  the  movable  plate  of  the  stapes  which  occupies  it,  in  animals  living  in  air 
but  destitute  of  tympanic  apparatus ;  this  is  naturally  the  case  in  many  Am- 
phibia ;  and  it  may  happen  as  the  result  of  disease  in  the  Human  subject.  la 


SENSE   OF   HEARING. 


899 


XI.  we  have  a  very  interesting  demonstration  of  the  purpose  and  action  of  the 
tympanum,  in  the  more  perfect  forms  of  the  auditory  apparatus. — We  are  now 
prepared  to  inquire,  in  somewhat  more  of  detail,  into  the  actions  of  the  differ- 
ent parts  of  this  apparatus  j  and  it  will  be  better  to  commence  with  those  of 
the  Middle  and  Internal  Ear,  the  accessory  organs  being  afterwards  considered. 
902.  The  Membrana  Tympani  consists  of  three  layers  :  an  external  one,  con- 
tinuous with  the  cutis  of  the  external  meatus,  and  consisting  of  dermoid  tissue 
with  a  covering  of  epidermic  cells }  an  internal  one,  which  is  extremely  thin, 
continuous  in  like  manner  with  the  mucous  membrane  lining  the  tympanic 

Fig.  220. 


Diagram  of  the  inner  wall  of  the  tympanum  after  maceration,  the  outer  wall  and  ossicles  being  removed 
a.  Fenestra  ovalis.  b.  Fenestra  rotunda,  c.  Promontory,  d.  Pyramid,  with  the  orifice  at  its  apex.  e.  Pro- 
jection of  the  aqueductus  Fallopii.  /.  Some  of  the  mastoid  cells  communicating  with  the  tympanum,  g. 
Processus  cochleariformis,  bounding  i,  the  canal  for  the  tensor  tympani  muscle :  the  anterior  pyramid  is 
broken  off,  if  it  existed,  h.  Commencement  of  the  Eustachian  tube.  j.  Jugular  fossa,  immediately  below  the 
tympanum,  k,  k.  Carotid  canal,  with  the  artery  in  outline,  to  show  its  course  in  relation  to  the  tympanum 
and  Euatachian  tube.  I.  Portio  dura  of  the  seventh  pair  of  nerves,  as  it  would  be  seen  in  the  terminal  part  of 
the  aqueduct  of  Fallopius.  TO.  Chorda  tympani,  leaving  the  portio  dura,  and  entering  a  short  canal,  which 
opens  in  the  tympanum,  at  the  base  of  the  pyramid,  n.  Grooves  for  the  tympanic  plexus. 

cavity,  and  also  composed  of  dermoid  tissue  and  epithelium;  and  a  middle  layer, 
which,  according  to  the  recent  researches  of  Mr.  Toynbee,1  may  be  separated 
into  two  distinct  laminae,  whose  fibres  run  in  contrary  directions,  those  of  the 
external  layer  (which  is  the  stronger  of  the  two)  radiating  from  the  malleus  to  wards 
the  peripheral  ring  to  which  they  are  attached,  whilst  those  of  the  internal  are 
annular.  The  fibres  of  which  these  laminae  are  composed  do  not  appear  to  be 
muscular ;  nor  do  they  present  the  longitudinal  parallel  wavy  lines  character- 
istic of  ordinary  fibrous  membranes ;  and  they  are  rendered  opaque  by  acetic 
acid.  Hence,  although  those  laminae  appear  to  be  derived,  the  external  from 
the  periosteum  of  the  meatus,  and  the  internal  from  that  of  the  tympanic 'cavity, 
they  differ  from  it  in  elementary  structure,  and  seem  to  have  more  in  common 
with  the  elastic  tissue.  Mr.  Toynbee  points  out  the  existence  of  a  tubular 
ligament,  inclosing  the  tendon  of  the  tensor  tympani  muscle ;  and  considers 
that  the  membrane  is  maintained  by  this  ligament  in  a  state  of  moderate  tension, 
the  assistance  of  the  muscle  being  only  required  to  augment  this. — The  function 

1  "  Philosophical  Transactions,"  1851. 


900  OF   SENSATION^    AND   THE   ORGANS   OF   THE    SENSES. 

of  the  Membrana  Tympani  seems  obviously  to  be  the  reception  of  sonorous  un- 
dulations from  the  air,  in  such  a  manner  that  it  may  be  thrown  by  them  into  a 
reciprocal  vibration,  which  is  communicated  to  the  chain  of  bones.  This  mem- 
brane, in  its  usual  state,  is  scarcely  on  the  stretch ;  and  this  is  found  by  experi- 
ment to  be,  for  a  small  membrane,  the  best  condition  for  the  propagation  of 

Fig.  221. 


Membrana  tympani  from  the  outer  (A)  and  from  Ossicles  of  the  left  ear  articulated,  and  seen  from  the 

the  inner  (B)  sides  :  1.  Membrana  tympani.  2.  outside  and  below,  m.  Head  of  the  malleus,  below 
Malleus.  3.  Stapes.  4.  Incus.  which  is  the  constriction,  or  neck.  g.  Processus  gra- 

cilis,  or  long  process,  at  the  root  of  which  is  the  shor  t 
process,  h.  Manubrium,  or  handle,  sc.  Short  crus ; 
and  Ic,  long  crus  of  the  incus.  The  body  of  this  bone 
is  seen  articulating  with  the  malleus,  and  its  long  crus, 
through  the  medium  of  the  orbicular  process,  here 
partly  concealed,  a,  with  the  stapes,  s.  Base  of  the 
stapes.  Slagnified  three  diameters.  From  Arnold. 

ordinary  undulations.  This  is  easily  rendered  sensible  in  one's  own  person ; 
for  an  increased  tension  may  be  given  to  the  membrana  tympani,  either  by 
holding  the  breath  and  forcing  air  into  the  Eustachian  tube,  so  as  to  distend  it 
from  within,  or  by  exhausting  the  cavity,  so  as  to  cause  the  external  air  to 
make  increased  pressure  upon  it ;  and  in  either  case,  the  hearing  is  found  im- 
mediately to  become  indistinct.  It  is  observed,  however,  that  grave  and  acute 
sounds  are  not  equally  affected  by  this  action ;  for  the  experimenter  renders 
himself  deaf  to  grave  sounds,  whilst  acute  sounds  are  heard  even  more  dis- 
tinctly than  before.  This  fact  is  easily  understood  by  referring  to  the  laws  of 
Acoustics  already  mentioned.  The  greater  the  tension  to  which  the  membrana 
tympani  is  subjected,  the  more  acute  will  be  its  fundamental  tone  :  and  as  no 
proper  reciprocation  can  take  place  in  it,  to  any  sound  lower  than  its  funda- 
mental tone,  its  power  of  repeating  perfectly  the  vibrations  proper  to  the  deeper 
notes  will  diminish.  The  nearer  a  sound  approaches  to  the  fundamental  note 
proper  to  the  tense  membrane,  the  more  distinctly  will  it  be  heard.  On  the 
other  hand,  when  the  membrane  is  in  its  natural  relaxed  condition,  its  funda- 
mental note  is  very  low,  and  it  is  capable  of  repeating  a  much  greater  variety  of 
sounds ;  for,  when  it  receives  undulations  of  a  higher  tone  than  those  to  which 
the  whole  membrane  would  reciprocate,  it  divides  itself  into  distinct  segments 
of  vibration,  which  are  separated  by  lines  of  rest ;  and  every  one  of  these  re- 
ciprocates the  sound,1  at  the  same  time  rendering  it  more  intense  by  multiplica- 

1  This  is  very  easily  proved  by  experiment  on  a  membrane  stretched  over  a  resonant 
cavity  ;  for  if  light  sand  be  strewed  upon  it,  and  a  strong  musical  tone  be  produced  in  its 
vicinity,  the  membrane  will  immediately  be  set  in  vibration,  not  as  a  whole  (unless  its 
fundamental  note  be  in  unison  with  that  sounded),  but  in  distinct  segments,  of  which 
every  one  reciprocates  the  sound ;  from  the  vibrating  parts,  the  sand  will  be  violently 
thrown  off ;  but  it  will  settle  on  the  intermediate  lines  of  rest,  forming  a  variety  of  curious 
figures  which  are  known  as  the  nodal  lines. 


SENSE   OF    HEARING.  901 

tion.  These  facts  enable  us  to  understand  the  influence  of  the  tensor  tympani 
muscle,  in  modifying  the  tension  of  the  membrane,  and  thus  causing  it  to  vibrate 
in  reciprocation  to  sounds  having  a  great  variety  of  fundamental  notes.  More- 
over, the  fact  that  some  persons  are  deaf  to  grave  sounds,  whilst  they  readily 
hear  the  more  acute,  is  thus  accounted  for.  The  tensor  tympani,  like  the  iris, 
is  probably  excited  to  operation  by  a  reflex  action ;  and  it  is  by  no  means  im- 
probable that  one  of  its  functions  may  be,  to  prevent  the  internal  ear  from 
being  too  violently  affected  by  loud  sounds,  by  putting  the  membrana  tympani 
into  such  a  state  of  tension  as  not  readily  to  reciprocate  them. 

903.  The  uses  of  the   Tympanic   Cavity  are  very  obvious.     One  of  its  pur- 
poses is  to  render  the  vibrations  of  the  membrane  quite  free ;  and  the  other,  to 
isolate  the  chain  of  bones,  in  such  a  manner  as  to  prevent  their  vibrations  from 
being  weakened  by  diffusion  through  the  surrounding  solid  parts.     As  to  the 
objects  of  the  Eustachian  tube,  however,  opinions  have  been  much  divided. 
From  the  experiments  of  M  tiller  it  appears  that  it  does  not  increase  the  intensity 
of  sound,  but  that  it  prevents  a  certain  degree  of  dulness  which  would  attend  it 
if  the  cavity  of  the  tympanum  were  completely  closed ;  of  this  dulness  we  are 
conscious,  when  any  tumefaction  of  the  fauces  causes  an  occlusion  of  the  ex- 
tremity of  the  tube.     It  has  been  supposed  that,  among  other  uses,  this  canal 
serves  for  the  conduction  of  the  speaker's  voice  to  his  ears ;  but  this  is  certainly 
not  the  case  in  any  considerable  degree ;  for,  when  the  Eustachian  tubes  are 
obstructed  by  disease,  the  patient  hears  his  own  voice  well,  though  other  sounds 
are  indistinct ;  and  it  is  easily  shown,  that  its  transmission  is  chiefly  accom- 
plished in  other  ways.     The  common  idea  is,  that  it  serves  the  same  purpose 
with  the  hole  in  an  ordinary  drum ;  the  effect  of  which  is  generally  supposed  to 
be  the  removal  of  an  impediment  to  the  vibrations  of  the  membrane,  that  would 
be  offered  by  the  complete  inclosure  of  the  air  within.     It  does  not  appear, 
however,  that  any  such  impediment  is  really  offered ;  and  the  effect  of  the  hole 
in  the  drum  seems  rather  to  be  the  communication,  to  the  ear  of  the  auditor,  of 
the  sonorous  vibrations  of  the  contained  air ;  which  are  thus  transmitted  directly 
through  the  atmosphere,  instead  of  being  weakened  by  transmission  through  the 
walls  of  the  instrument.     Hence  there  is  no  real  analogy  in  the  two  cases.    The 
principal  object  of  the  Eustachian  tube  (which  is  always  found  where  there  is  a 
tympanic  cavity)  seems  to  be,  the  maintenance  of  the  equilibrium  between  the 
air  within  the  tympanum  and  the  external  air ;  so  as  to  prevent  inordinate  ten- 
sion of  the  membrana  tympani,  which  would  be  produced  by  too  great  or  too 
little  pressure  on  either  side,  and  the  effect  of  which  would  be  imperfection  of 
hearing.     It  also  has  the  office  of  conveying  away  mucus  secreted  in  the  cavity 
of  the  tympanum,  by  means  of  the  vibratile  cilia  which  clothe  its  lining  mem- 
brane ;  and  the  deafness,  consequent  on  occlusion  of  this  tube,  is  in  part  ex- 
plicable by  the  accumulation  which  will  then  take  place  in  the  cavity. 

904.  From  what  has  been  stated,  it  is  evident  that  sonorous  undulations, 
taking  place  in  the  air,  will  be  propagated  to  the  fluid  contained  in  the  labyrinth 
— through  the  tympanum,  the  chain  of  bones,  and  the  membrane  of  the  fenestra 
ovalis  to  which  the  stapes  is  attached — without  any  loss,  but  rather  an  increase 
of  intensity.     Why  water  should  be  chosen  as  the  medium  through  which  the 
impression  is  to  be  made  upon  the  nerve,  it  is  impossible  for  us  to  say  with 
anything  like  certainty,  in  our  present  state  of  ignorance  as   to  the  physical 
character  of  that  impression.     But  the  problem  being  to  communicate  to  water 
the  sonorous  undulations  of  air,  the  experimental  results  already  detailed  satis- 
factorily prove  that — whilst  this  may  be  accomplished,  in  a  degree  sufficient  for 
the  wants  of  the  inferior  animals,  by  the  simple  interposition  of  a  tense  mem- 
brane between  the  air  and  the  fluid — the  tympanic  apparatus  of  the  higher 
classes  is  most  admirably  adapted  for  this  purpose.     The  fenestra  ovalis  is  not, 
however,  the  only  channel  of  communication  between  the  tympanum  and  the 


902  OF   SENSATION,   AND   THE   ORGANS   OF   THE    SENSES. 

labyrinth ;  for  there  is,  in  most  animals,  a  second  aperture,  the  fenestra  rotunda, 
leading  into  the  cochlea,  and  simply  covered  with  a  membrane.  It  is  generally 
supposed  that,  the  labyrinth  being  filled  with  a  nearly  incompressible  fluid,  this 
second  aperture  is  necessary  to  allow  the  free  vibration  of  that  fluid;  the  mem- 
brane of  the  fenestra  rotunda  being  made  to  bulge  out,  as  that  of  the  fenestra 
ovalis  is  pushed  in.  It  may,  however,  be  easily  shown  by  experiment,  as  well 
as  by  reference  to  comparative  anatomy,  that  no  such  contrivance  is  necessary  ; 
for  sonorous  undulations  may  be  excited  in  a  non-elastic  fluid,  completely  in- 
closed within  solid  walls  at  every  part,  except  where  these  are  replaced  by  the 
membrane  through  which  the  vibrations  are  propagated ;  and  this  is  precisely 
the  condition,  not  only  of  the  Invertebrated  animals,  but  even  of  Frogs;  in 
which  last  a  tympanic  apparatus  exists,  without  a  second  orifice  into  the  laby- 
rinth. Moreover,  it  is  certain  that  the  vibrations  of  the  air  in  the  cavity  of  the 
tympanum  must  of  themselves  act  upon  the  membrane  of  the  fenestra  rotunda; 
and  this  is,  perhaps,  the  most  direct  manner  in  which  the  fluid  in  the  cochlea 
will  be  affected,  although  it  will  ultimately  be  thrown  into  much  more  powerful 
action  by  the  transmission  of  vibrations  from  the  vestibule.  For  it  has  been 
satisfactorily  determined  by  experiment  (xn.)  that  vibrations  are  transmitted 
with  very  much  greater  intensity  to  water,  when  a  tense  membrane,  and  a 
chain  of  insulated  solid  bodies  capable  of  free  movement,  are  successively  the 
conducting  media,  than  when  the  media  of  communication  between  the  vibrating 
air  and  the  water  are  the  same  tense  membrane,  air,  and  a  second  membrane  : 
or,  to  apply  this  fact  to  the  organ  of  hearing,  the  same  vibrations  of  the  air  act 
upon  the  fluid  of  the  labyrinth  with  much  greater  intensity,  through  the  medium 
of  the  chain  of  auditory  bones  and  the  fenestra  ovalis,  than  through  the  medium 
of  the  air  of  the  tympanum  and  the  membrane  closing  the  fenestra  rotunda. — 

Fig.  223. 


A  view  of  the  labyrinth  of  the  Left  Side,  laid  open  in  its  whole  extent  so  as  to  show  its  Structure ;  these 
figures  are  all  magnified:  1,  the  thickness  of  the  outer  covering  of  the  cochlea;  2,  2,  the  scala  vestibuli,  or 
upper  layer  of  the  lamina  spiralis ;  3,  3,  the  scala  tympani  or  lower  layer  of  the  lamina  spiralis  ;  4,  the  ha- 
mulus  cochleae ;  5,  centre  of  the  infundibulum ;  6,  the  foramen  rotundum  communicating  with  the  tym- 
panum ;  7,  the  thickness  of  the  outer  layer  of  the  vestibule ;  8,  the  foramen  rotundum  ;  9,  the  fenestra  ovalis ; 
10,  the  orifice  of  the  aqueduct  of  the  vestibule;  11,  the  inferior  semicircular  canal;  12,  the  superior  semi- 
circular canal ;  13,  the  external  semicircular  canal ;  14,  the  ampulla  of  the  inferior  canal;  15,  the  ampulla  of 
the  superior  canal;  16,  the  common  orifice  of  the  superior  and  inferior  canals;  17,  the  ampulla  of  the  external 


SENSE   OF   HEARING. 


903 


The  fenestra  rotunda  is  not  to  be  considered  as  having  any  peculiar  relation 
with  the  cochlea ;  since,  in  the  Turtle  tribe,  the  former  exists  without  the 
latter. 

905.  It  is  obviously  in  the  Labyrinth,  as  a  whole,  that  the  sonorous  vibra- 
tions are  brought  to  bear  upon  the  Auditory  nerve  spread  out  to  receive  them. 

Fig.  224. 


The  soft  parts  of  the  Vestibule  taken  out  of  their  bony  case,  so  as  to  show  the  distribution  of  the  Nerves 
in  the  Ampullae :  1,  the  superior  semicircular  membranous  canal  or  tube ;  2,  the  external  semicircular  tube ; 
3,  the  inferior  semicircular  tube ;  4,  the  tube  of  union  of  the  superior  and  inferior  canals ;  5,  the  sacculus 
ellipticus;  6,  the  sacculus  sphericus ;  7,  the  portio  dura  nerve;  8,  the  anterior  fasciculus  of  the  auditory  nerve ; 
9,  the  nerve  to  the  sacculus  sphericus ;  10, 10,  the  nervous  fasciculi  to  the  superior  and  external  ampullae ; 
11,  the  nerve  to  the  sacculus  ellipticus ;  12,  the  posterior  fasciculus  of  the  auditory  nerve,  furnishing,  13,  the 
filaments  of  the  sacculus  sphericus,  and,  14,  the  filaments  of  the  cochlea,  cut  off. 

In  regard  to  the  special  functions  of  particular  parts  of  the  labyrinth,  however, 
no  certainty  can  be  said  to  exist.     The  membrane  which  lines  its  cavities  not 

Fig.  225. 


The  Ampullae  of  the  External  Semicircular  Membranous  Canal,  showing  the  mode  of  termination  of  its 
Nerve. 


904 


OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 


only  contains  a  liquid  (the  endo-lympTi),  but  is  also  separated  from  the  osseous 
wall  by  another  collection  of'liquid,  the  peri-lymph;  so  that  it  is  suspended,  as 
it  were,  in  a  liquid  which  bathes  both  its  surfaces.  In  the  cavity  of  the  Vesti- 
bule, which  is  subdivided  by  a  membranous  partition  into  two,  are  found  small 
masses  of  concretionary  particles,  collectively  named  otoconia,  or  ear-powder ; 
these  are  obviously  the  rudiments  of  the  otoliths,  or  ear-stones,  whose  presence 
in  animals  with  a  less  perfect  auditory  apparatus  seems  needful  to  intensify  the 
undulations.  It  is  commonly  supposed  that  the  Semicircular  Canals  have  for 
their  peculiar  function,  to  receive  the  impressions  by  which  we  distinguish  the 

Fig.  226. 


A  view  of  the  axis  of  the  Cochlea  and  the  Lamina  Spiralis,  showing  the  arrangement  of  the  three  Zones ; 
the  osseous  zone  and  the  membrane  of  the  vestibule  have  been  removed :  1,  the  natural  size  of  the  parts ; 
the  other  figure  is  greatly  magnified ;  2,  trunk  of  the  auditory  nerve ;  3,  the  distribution  of  its  filaments  in 
the  zona  ossea ;  4,  the  nervous  anastomosis  of  the  zona  vesicularis ;  5,  the  zona  membranacea ;  6,  the  osseous 
tissue  of  the  modiolus ;  7,  the  opening  between  the  two  scalae. 

direction  of  sounds ;  and  it  is  certainly  a  powerful  argument  in  support  of  this 
view  that,  in  almost  every  instance  in  which  these  parts  exist  at  all,  they  hold 
the  same  relative  position  to  each  other  as  in  Man,  their  three  planes  being 

Fig.  227. 


Cochlea  of  a  new-born  infant,  opened  on  the  side  towards  the  apex  of  the  petrous  bone.  It  shows  the 
general  arrangement  of  the  two  scalae,  the  lamina  spiralis,  and  the  distribution  of  the  cochlear  nerve.  At 
the  apex  is  seen  the  modiolus  expanding  into  the  cupola,  where  the  spiral  canal  terminates  in  a  cul-de-sac. 
The  helicotrema  is  not  visible  in  this  view.  From  Arnold. 

nearly  at  right  angles  to  one  another.     The  idea,  however,  must  be  regarded  as 
a  mere  speculation,  the  value  of  which  cannot  be  decided  without  an  increased 


SENSE   OF    HEARING.  905 

knowledge  of  the  laws  according  to  which  sonorous  vibrations  are  transmitted. 
— Regarding  the  special  function  of  the  Cochlea,  there  is  precisely  the  same 
uncertainty.  This  part  of  the  organ  is  peculiar  in  one  respect,  that  the  expan- 
sion of  the  auditory  nerve  is  here  spread  out  (within  the  lamina  spiralis)  in 
closer  proximity  with  the  bone  itself,  than  it  is  in  any  other  part  of  the  laby- 
rinth ;  and  moreover  the  peri -lymph  is  here  deficient,  so  that  the  membranous 
lining  of  the  cochlea  is  in  absolute  contact  with  its  osseous  wall.  It  is  not 
easy  to  see,  however,  what  can  be  the  peculiar  object  of  this  disposition,  in 
regard  to  the  function  of  hearing.  It  has  been  surmised  by  M.  Duges  that,  by 
the  cochlea,  we  are  especially  enabled  to  estimate  the  pitch  of  sounds,  particu- 
larly of  the  voice ;  and  he  adduces,  in  support  of  this  idea,  the  fact  that  the 
development  of  the  cochlea  follows  a  very  similar  proportion  with  the  compass 
of  the  voice.  This  is  much  the  greatest  in  the  Mammalia ;  less  in  Birds;  and 
in  Reptiles,  which  have  little  true  vocal  power,  the  cochlea  is  reduced  to  its 
lowest  form,  disappearing  entirely  in  the  Amphibia.  That  there  should  be  an 

Fig.  228. 


The  Cochlea  divided  parallel  with  its  axis,  through  the  centre  of  the  Modiolus ;  after  Breschet :  1,  the 
modiolus ;  2,  the  infundibulum  in  which  the  modiolus  terminates ;  3,  3,  the  cochlear  nerve,  sending  its  fila- 
ments through  the  centre  of  the  modiolus;  4,  4,  the  scala  tympani  of  the  first  turn  of  the  cochlea;  5,  5,  the 
scala  vestibula  of  the  first  turn ;  6,  section  of  the  lamina  spiralis,  its  zonula  ossea ;  one  of  the  filaments  of 
the  cochlear  nerve  is  seen  passing  hetween  the  two  layers  of  the  lamina  spiralis  to  be  distributed  upon  the 
membrane  which  invests  the  lamina ;  7,  the  membranous  portion  of  the  lamina  spiralis ;  8,  loops  formed  by 
the  filaments  of  the  cochlear  nerve  ;  9,  9,  the  scala  tympani  of  the  second  turn  of  the  cochlea;  10,  10,  scala 
vestibula  of  the  second  turn;  the  septum  between  the  two  is  the  lamina  spiralis;  11,  the  scala  tympani  of 
the  remaining  half  turn ;  12,  the  remaining  half  turn  of  the  scala  vestibula— the  dome  placed  over  this  half 
turn  is  the  cupola ;  13,  the  lamina  of  bone  which  forms  the  floor  of  the  scala  vestibula  curving  spirally 
round  to  constitute  the  infundibulum  (2)  ;  14,  the  helicotrema  through  which  a  bristle  is  passed ;  its  lower 
extremity  issues  from  the  scala  tympani  of  the  middle  turn  of  the  cochlea. 

acoustic  relation  between  the  voice  and  ear  of  each  species  of  animal,  cannot  be 
regarded  as  improbable ;  but  the  speculation  of  M.  Duges  can  at  present  only 
be  received  as  a  stimulus  to  further  inquiry. 

906.  We  have  now  to  consider  the  functions  of  the  accessory  parts — the 
External  Ear,  and  the  Meatus.  The  Cartilage  of  the  external  ear  may  propa- 
gate sonorous  vibrations  in  two  ways ;  by  reflection  and  by  conduction.  In 
reflection,  the  concha  is  the  most  important  part,  since  it  directs  the  reflected 
undulations  towards  the  tragus,  whence  they  are  thrown  into  the  auditory  pas- 
sage. The  other  inequalities  of  the  external  ear  cannot  promote  hearing  by 
reflection ;  and  the  purpose  of  the  extension  of  its  cartilage  is  evidently  to 
receive  the  sonorous  vibrations  from  the  air,  and  to  conduct  them  to  its  point  of 
attachment.  In  this  point  of  view,  the  inequalities  become  of  importance ; 
for  those  elevations  and  depressions  upon  which  the  undulations  fall  perpen- 
dicularly, will  be  affected  by  them  in  the  most  intense  degree ;  and  in  conse- 
quence of  the  varied  form  and  position  of  these  inequalities,  sonorous  undula- 
tions, in  whatever  direction  they  may  come,  must  fall  advantageously  upon 


906 


OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 


some  of  them. — The  functions  of  the  Meatus  appear  to  be  threefold.  The 
sonorous  undulations  entering  from  the  atmosphere  are  propagated  directly, 
without  dispersion,  to  the  membrana  tympani : — the  sonorous  undulations 


Fig.  229. 


Fig.  230. 


A  view  of  the  Left  Ear  in  its  natural  state :  1,  2, 
the  origin  and  termination  of  the  helix ;  3,  the  anti- 
helix  ;  4,  the  anti-tragus ;  5,  the  tragus ;  6,  the  lobus 
of  the  external  ear;  7,  points  to  the  scapha  and  is 
on  the  front  and  top  of  the  pinna;  8,  the  concha;  9, 
the  meatus  auditorius  externus. 


An  anterior  view  of  the  External  Ear,  as  well  as 
of  the  Meatus  Auditorius,  Labyrinth,  Ac.:  1,  the 
opening  into  the  ear  at  the  bottom  of  the  concha ; 
2,  the  meatus  auditorius  externus  or  cartilaginous 
canal;  3,  the  membrana  tympani  stretching  upon 
its  ring;  4,  the  malleus  ;  5,  the  stapes;  6,  the  laby- 
rinth. 


received  on  the  external  ear  are  conveyed  along  the  walls  of  the  meatus  to  the 
membrana  tympani :  the  air  which  it  contains,  like  all  insulated  masses  of  air, 
increases  the  intensity  of  sounds  by  resonance.  That,  in  ordinary  hearing, 
the  direct  transmission  of  atmospheric  vibrations  to  the  membrana  tympani  is 
the  principal  means  of  exciting  the  reciprocal  vibrations  of  the  latter,  is  suffi- 
ciently evident ;  the  undulations  which  directly  enter  the  passage  will  pass 
straight  on  to  the  membrane ;  while  those  that  enter  obliquely  will  be  reflected 
from  side  to  side,  and  at  last  will  fall  obliquely  on  the  membrane,  thus  perhaps 
contributing  to  the  notion  of  direction.  The  power  of  the  lining  of  the  meatus 
to  conduct  sound  from  the  external  ear  is  made  evident  by  the  fact  that,  when 
both  ears  are  closely  stepped,  the  sound  of  a  pipe  having  its  lower  extremity 
covered  by  a  membrane,  is  heard  more  distinctly  when  it  is  applied  to  the 
cartilage  of  the  external  ear  itself,  than  when  it  is  placed  in  contact  with  the 
surface  of  the  head.  The  resonant  action  of  the  air  in  the  tube  is  easily  demon- 
strated, by  lengthening  the  passage  by  the  introduction  of  another  tube  j  the 
intensity  of  external  sounds,  and  also  that  of  the  individual's  own  voice,  as 
heard  by  himself,  are  then  much  increased. 

907.  Many  facts  prove,  however,  that  the  fluid  of  the  Labyrinth  may  be 
thrown  into  vibration  in  other  ways  than  by  the  Tympanic  apparatus.  Thus,  in 
Osseous  Fishes,  it  is  only  by  the  vibrations  transmitted  through  the  bones  of  the 
head  that  hearing  can  take  place.  There  are  many  persons,  again,  who  can 
distinctly  hear  sounds  which  are  thus  transmitted  to  them;  although,  through 
some  imperfection  of  the  tympanic  apparatus,  they  are  almost  insensible  to  those 
which  they  receive  in  the  ordinary  way.  It  is  evident,  where  this  is  the  case, 
that  the  nerve  must  be  in  a  state  fully  capable  of  functional  activity;  and,  on 


SENSE   OF   HEARING.  907 

the  other  hand,  where  sounds  cannot  thus  be  perceived,  there  will  be  good  rea- 
son to  believe  that  the  nerve  is  diseased. 

908.  A  single  impulse  communicated  to  the  Auditory  nerve,  in  any  of  the 
foregoing  modes,  seems  to  be  sufficient  to  excite  the  momentary  sensation  of 
sound  ;  but  most  frequently  a  series  of  such  impulses  is  concerned,  there  being 
but  few  sounds  which  do  not  partake,  in  a  greater  or  less  degree,  of  the  charac- 
ter of  a  tone.     Any  continuous  sound  or  tone  is  dependent  upon  a  succession  of 
impulses;   and  its  acuteness  or  depth  is  governed  by  the  rapidity  with  which 
these  succeed  one  another.     It  is  not  difficult  to  ascertain,  by  experiment,  what 
number  of  such  impulses  or  undulations  are  required,  to  give  every  tone  which 
the  ear  can  appreciate.     Thus,  if  a  circular  plate,  with  a  number  of  apertures 
at  regular  intervals,  be  made  to  revolve  over  the  top  of  a  pipe  through  which 
air  is  propelled,  a  succession  of  short  puffs  will  be  allowed  to  issue  from  this; 
and,  if  the  revolution  be  sufficiently  rapid,  these  impulses  will  unite  into  a  defi- 
nite tone.     In  the  same  manner,  if  a  spring  be  fixed  near  the  edge  of  a  re- 
volving toothed  wheel,  in  such  a  manner  as  to  be  caught  by  every  tooth  as  it 
passes,  a  succession  of  clicks  will  be  heard ;  and  these,  too,  if  the  revolution  of 
the  wheel  be  sufficiently  rapid,  will  produce  a  tone.     The  number  of  apertures 
in  the  plate  which  pass  the  orifice  of  the  pipe  in  a  given  time,  or  the  number 
of  teeth  which  pass  the  spring,  being  known,  it  is  easy  to  see  that  this  must  be 
the  number  of  impulses  required  to  produce  the  given  tone.     Each  impulse 
produces  a  double  vibration — forwards  and  backwards  (as  seen  when  a  string  is 
put  in  vibration,  by  pulling  it  out  of  the  straight  line);  hence  the  number  of 
impulses  is  always  half  that  of  the  single  vibrations.     The  maximum  and  mini- 
mum of  the  intervals  of  successive  pulses,  still  appreciable  by  the  ear  as  deter- 
minate sounds,  have  also  been  determined  by  M.  Savart,  more  satisfactorily  and 
more  accurately  than  had  previously  been  done.     If  their  intensity  be  great, 
sounds  are  still  audible  which  result  from  the  succession  of  24,000  impulses  in 
a  second;  and  this,  probably,  is  not  the  extreme  limit  to  the  acuteness  of  sounds 
perceptible  by  the  ear.     From  some  observations  of  Dr.  Wollaston's,  it  seems 
probable  that  the  ears  of  different  individuals  are  differently  constituted  in  this 
respect — some  not  being  able  to  hear  very  acute  tones  produced  by  Insects,  or 
even  Birds,  which  are  distinctly  audible  to  others.     Again,  the  sound  resulting 
from  16  impulses  per  second,  is  not,  as  has  been  usually  supposed,  the  lowest 
appreciable  note;  on  the  contrary,  M.  Savart  has  succeeded  in  rendering  tones 
distinguishable  which  are  produced  by  only  7  or  8  impulses  in  a  second;  and 
continuous  sounds  of  a  still  deeper  tone  could  be  heard,  if  the  individual  pulses 
were  sufficiently  prolonged.    In  regard,  however,  to  the  precise  time  during  which 
a  sonorous  impression  remains  upon  the  ear,  it  is  difficult  to  procure  exact  in- 
formation, since  it  departs    more  gradually  than  do  visual  impressions  from 
the  eye.     This  is  certain,  however — that  it  is  much  longer  than  the  interval 
between  the  successive  pulses  in  the  production  of  tones ;  since  it  was  found  by 
M.  Savart,  that  one  or  even  several  teeth  might  be  removed  from  the  toothed 
wheel,  without  a  perceptible  break  in  its  sound — showing  that,  when  the  tone 
was  once  established,  the  impression  of  it  remained  during  an  intermission  of 
some  length. 

909.  The  Ear,  like  the  Eye,  may  vary  considerably  as  regards  general  acute- 
ness,  amongst  different  individuals;  and  its  power  may  be  much  increased  by 
practice.     A  part  of  this  increase  depends,  however,  as  in  other  instances,  upon 
the  greater  attention  which  its  fainter  indications  receive ;  but  a  part,  also,  upon 
an  increased  use  of  the  organ.     The  power  of  hearing  very  faint  sounds  is  as 
different  from  the  power  of  distinguishing  musical  tones,  as  the' power  of  dis- 
cerning very  minute  objects,  or  of  seeing  with  very  faint  degrees  of  light,  is 
from  that  of  distinguishing  colors.     Many  persons  are  altogether  destitute  of 
what  is  termed  a  musical  ear;  whilst  others  are  endowed  with  it  in  a  degree 


908     OF  SENSATION,  AND  THE  ORGANS  OF  THE  SENSES. 

which  is  a  source  of  great  discomfort  to  them,  since  every  discordant  sound  is 
a  positive  torment.  The  power  of  distinguishing  the  direction  of  sounds  appears 
to  be,  in  Man  at  least,  for  the  most  part  acquired  by  habit.  It  is  some  time 
before  the  infant  seems  to  know  anything  of  the  direction  of  noises  which  attract 
his  attention.  Now,  although  there  can  be  no  question  that  this  perception  is 
acquired  by  attention  to  certain  variations  in  the  impressions  made  upon  the 
nerve,  through  the  medium  either  of  the  tympanic  apparatus,  or  of  the  bones 
of  the  head,  yet  it  is  equally  evident,  that  there  can  be  nothing  in  these  varia- 
tions themselves  adequate  to  excite  the  idea,  and  that  it  must  therefore  be  either 
intuitive  or  acquired  by  habit.  This  is  a  consideration  of  some  importance,  in 
regard  to  the  similar  question  as  to  the  sense  of  Visual  direction.  In  some 
cases  we  are  probably  assisted  by  the  relative  intensity  of  the  sensations  commu- 
nicated by  the  two  ears  respectively.  The  idea  of  the  distance  of  the  sonorous 
body  is  another  acquired  perception,  depending  principally  upon  the  loudness  or 
faintness  of  the  sound,  when  we  have  no  other  indications  to  guide  us.  In  this 
respect  there  is  a  great  similarity  between  the  perception  of  the  distance  of  an 
object,  through  the  Eye  by  its  size,  and  through  the  Ear  by  the  intensity  of  its 
sound.  When  we  know  the  size  of  the  object,  or  are  acquainted  with  the  usual 
intensity  of  its  sound,  we  can  judge  of  its  distance;  and  vice  versa,  when  we 
know  its  distance,  we  can  at  once  form  an  idea  of  its  real  from  its  apparent  size, 
and  of  its  real  strength  of  tone  from  that  which  affects  our  ears.  In  this  manner 
the  mind  may  be  affected  with  corresponding  deceptions  through  both  senses; 
thus,  in  the  Phantasmagoria,  the  figure  being  gradually  diminished  whilst  its 
distance  remains  the  same,  it  appears  to  the  spectators  to  recede,  the  illusion 
being  more  complete  if  its  brightness  be  at  the  same  time  diminished ;  and  the 
effect  of  a  distant  full  military  band  gradually  approaching,  may  be  alike  given 
by  a  corresponding  crescendo  of  concealed  instruments.  It  is  upon  the  complete 
imitation  of  the  conditions  which  govern  our  ideas  of  the  intensity  and  direction, 
as  well  as  of  the  character,  of  sounds,  that  the  deceptions  of  the  Ventriloquist 
are  founded. 

910.  Some  facts  of  much  interest  have  lately  been  ascertained,  in  regard  to 
an  occasional  variation  in  the  rapidity  of  the  perception  of  sensory  impressions, 
received  through  the  Eye  and  through  the  Ear.     These  facts  are  the  result  of 
comparisons  made  amongst  different  astronomical  observers,  who  may  be  watch- 
ing the  same  visual  phenomenon,  and  timing  their  observations  by  the  same 
clock ;  for  it  has  been  remarked,  that  some  persons  see  the  same  occurrence  a 
third  or  even  a  half  of  a  second  earlier  than  others.     There  is  no  reason  to  suppose 
from  this,  however,  that  there  is  any  difference  in  the  rate  of  transmission  of 
the  sensory  impressions  in  the  two  nerves.     The  fact  seems  rather  to  be  that  the 
Sensorium  does  not  readily  perceive  two  different  impressions  with  equal  dis- 
tinctness ;   and  that,  when  several  impressions  are  made  on  the  senses  at  the 
same  time,  the  mind  takes  cognizance  of  one  only,  or  perceives  them  in  succes- 
sion.    When,  therefore,  both  sight  and  hearing  are  directed  simultaneously  to 
two  objects,  the  communication  of  the  impression  through  one  sense  will  neces- 
sarily precede  that  made  by  the  other.     The  interval  between  the  two  sensations 
is  greater  in  some  persons  than  in  others ;  for  some  can  receive  and  be  conscious 
of  many  impressions,  seemingly  at  the  same  moment ;  whilst  in  others  a  per- 
ceptible space  must  elapse. 

911.  Amongst  other  important  offices  of  the  power  of  Hearing,  is  that  of 
supplying  the  sensations  by  which  the  Voice  is  regulated.     It  is  well  known 
that  those  who  are  born  entirely  deaf  are  also  dumb;  that  is,  they  do  not 
spontaneously  or  imitatively  form  articulate  sounds,  though  not  the  least  de- 
fect exist  in  their  organs  of  voice.     Hence  it  appears  that  the  vocal  muscles 
are  usually  guided  in  their  action  by  the  sensations  received  through  the  Ears, 
in  the  same  manner  as  other  muscles  are  guided  by  the  sensations  received 


MUSCULAR   MOVEMENTS.  909 

through  themselves ;  but  when  the  former  are  deficient,  the  action  of  the  vocal 
muscles  may  be  guided  by  the  latter  (§  751). 


CHAPTER    XVI. 

OF   MUSCULAR   MOVEMENTS. 

1. —  General  Considerations. 

912.  BY  far  the  larger  proportion  of  the  Muscular  apparatus  of  the  Human 
Body  may  be  considered  in  the  light  of  an  instrument  whereby  the  Nervous 
System  is  enabled  to  give  motion  to  its  parts,  and  thus  to  effect  those  changes, 
in  its  relation  to  the  external  world,  which  are  requisite  for  its  physical  well- 
being,  or  which  are  the  expressions  of  its  psychical  powers.  There  is  probably 
no  part  of  the  Muscular  System  which  is  altogether  beyond  the  pale  of  Nervous 
agency ;  but  a  tolerably  definite  line  of  demarcation  may  be  drawn,  both  struc- 
turally and  functionally,  between  the  two  primary  subdivisions  of  this  system , 
in  the  first  of  which — the  Muscular  Apparatus  of  Organic  Life — the  actions  are 
but  little  dependent  upon  nervous  agency ;  whilst  in  the  second — the  Muscular 
Apparatus  of  Animal  Life — scarcely  any  action  takes  place  but  what  is  called 
forth  by  nerve-force.  The  First  group  consists  of  the  muscular  envelops  which 
surround  the  various  open  cavities  of  the  body,  and  which  form  part  of  its  ge- 
neral investment ;  its  office  being  to  aid  in  the  performance  of  the  Organic 
functions,  by  giving  motion  to  the  contents  of  the  cavities,  or  by  maintaining  a 
proper  state  of  tension  around  them ;  and  it  is  composed  almost  entirely  of  the 
non-striated  or  smooth  form  of  muscular  fibre,  the  only  marked  exception  being 
in  the  case  of  the  heart.  Under  this  category  rank  the  proper  muscular  coat  of 
the  alimentary  canal,  from  its  commencement  in  the  oasophagus  to  its  termina- 
tion at  the  anus ;  the  muscular  coats  of  the  gland-ducts  which  discharge  them- 
selves into  this ;  the  muscular  fibres  of  the  trachea  and  bronchial  tubes ;  the 
muscular  substance  of  the  heart,  and  the  muscular  coats  of  the  bloodvessels  and 
absorbents  generally  j  the  muscular  walls  of  the  ureters,  bladder,  urethra,  and 
vasa  deferentia  in  the  male,  and  of  the  ureters,  bladder,  urethra,  Fallopian  tubes, 
uterus,  and  vagina  of  the  female ;  and  finally,  the  muscular  substance  of  the 
skin.  With  regard  to  nearly  all  these  parts,  as  already  pointed  out,  it  is  difficult 
to  obtain  evidence  that  nervous  agency  has  anything  to  do  with  their  contrac- 
tions ;  and  all  the  evidence  yet  adduced  tends  only  to  show  that  contractions 
may  be  excited  through  the  nervous  system,  not  that  they  habitually  are  so  ;  their 
ordinary  contractions  being  produced  either  by  their  own  motility  (§  499),  or  by 
stimuli  directly  applied  to  themselves. — The  Second  of  the  above-named  divisions 
consists  of  all  those  muscles  which  are  usually  styled  voluntary,  since  they  can 
be  put  or  retained  in  action  by  the  mandates  of  the  Will ;  but  besides  these,  it 
includes  a  large  group  of  muscles  (those,  namely,  that  are  concerned  in  the 
functions  of  Deglutition,  Respiration,  Yomiting,  Defecation,  and  Urination), 
over  which  the  Will  exerts  only  a  partial  control,  their  activity  being  usually 
called  forth  automatically.  It  would  seem  as  if  this  group  were  placed  under 
the  same  conditions,  as  regards  their  dependence  on  Nervous  agency,  with  those 
more  properly  termed  voluntary,  in  order  that  the  Will,  which  is  altogether 
powerless  over  the  Muscular  Apparatus  of  Organic  Life,  may  bring  their  opera- 
tions into  harmony  with  the  general  requirements  of  the  system;  the  functions 
in  question  being  those  which  constitute  (so  to  speak)  the  meeting-points  be- 
tween the  Organic  and  Animal  life.  For  as  we  descend  the  scale  of  animal 


910  OP   MUSCULAR   MOVEMENTS. 

life,  we  find  that  they  lose  more  and  more  of  the  character  they  possess  in  Man, 
becoming  more  and  more  exclusively  automatic,  and  at  last  being  even  trans- 
ferred from  the  more  elaborate  mechanism  of  muscular  contraction,  to  the  simple 
operation  of  ciliary  vibration.1  Nearly  all  those  muscles  in  the  Human  body, 
which  are  ordinarily  called  into  action  by  the  Cranio-Spinal  nerves,  are  composed 
of  striated  fibre ;  the  most  remarkable  exception  being  the  muscular  structure  of 
the  Iris.  And  it  is  peculiarly  characteristic  of  them  that,  whilst  forcible  and 
united  contractions  of  all  the  fasciculi  at  once  are  called  forth  by  irritating 
their  nerves,  the  effect  of  direct  stimulation  is  limited  to  the  fasciculus  irri- 
tated. 

913.  It  is  obvious,  from  what  has  preceded,  that  the  system  of  classifying  the 
Muscles  under  the  categories  of  voluntary  and  involuntary,  cannot  be  consist- 
ently maintained.     It  is  quite  true  that  all  the  Muscles  of  Organic  Life  may 
be  truly  styled  "  involuntary  •"  for,  although  they  are  capable  of  being  influenced 
by  emotional  and  ideational  states  of  mind  (§  923),  yet  the  Will  cannot  exert 
any  direct  influence  upon  them,  only  affecting  them  indirectly  by  its  power  of 
determining  these  states.     But  over  those  Muscles,  also  ministering  to  the  Or- 
ganic functions,  and  doing  so  in  obedience  to  impulses  purely  automatic,  which 
are  called  into  action  by  the  Cranio-Spinal  nerves,  the  Will,  as  we  have  seen, 
exerts  some  power ;  and  such,  therefore,  cannot  be  properly  regarded  as  involun- 
tary, since  the  Will  can  influence  their  actions ;  whilst  they  are  far  from  being 
truly  voluntary,  since  the  Will  cannot  control  their  tendency  to  automatic  action 
beyond  a  certain  limited  amount.     On  the  other  hand,  every  one  of  the  Muscles 
usually  styled  voluntary,  because  ordinarily  called  into  action  by  the  Will,  is 
liable  to  be  thrown  into  action  involuntarily ;  either  by  an  Excito-motor  stimulus, 
as  in  tetanic  convulsions,  or  by  Consensual  action,  as  in  tickling,  or  Emotion- 
ally, as  in  laughter  or  rage,  or  simply  Ideationally,  as  in  somnambulism  and 
analogous  states.     Hence,  although  there  are  certain  groups  of  muscles  which 
are  more   frequently  acted   on  by  the  Will  than  by  any  other  impulse,  and 
certain  others  which  are  more  frequently  played  on  by  the  Emotions,  and  so  on, 
it  becomes  obvious  that  every  muscle  called  into  contraction  by  the  Cranio-Spinal 
nervous  system  is  capable  of  receiving  its  stimulus  to  movement  from  any  of 
these  sources  j  the  nerve-force  transmitted  along  the  motor  fibres  being  issued 
either  from  the  Spinal  Cord,  from  the  Sensory  Granglia,  or  from  the  Cerebrum, 
as  the  case  may  be,  but  being  in  its  nature  and  effects  the  same  in  every  in- 
stance. 

914.  The  grouping  or  combination  of  Muscular  actions,  which  takes  place 
in  almost  every  movement  of  one  part  of  the  body  upon  another,  must  be  at- 
tributed, not  to  any  peculiar  sympathy  among  the  Muscles  themselves,  but  to 
the  mode  in  which  they  are  acted  on  by  the  Nervous  Centres.     This  is  most  ob- 
viously the  case  with  regard  to  those  of  the  primarily  automatic  class ;  but  it 
cannot  be  in  the  least  degree  doubtful,  as  to  those  of  the  secondarily  automatic 
kind  (such  as  walking),  which,  though  at  first  directed  by  the  Will,  come  by 
habit  to  be  performed  under  conditions  essentially  the  same  with  the  preceding; 
and  when  it  is  borne  in  mind  that  even  in  voluntary  movements  the  Will  cannot 
single  out  any  one  muscle  from  the  group  with  which  it  usually  co-operates,  so 
as  to  throw  this  into  separate  contraction,  but  is  limited  to  determining  the 
result  (§  758),  it  seems  pretty  obvious  that  even  here  the  grouping  is  efl'ected 
by  the  endowments  of  the  Automatic  centres  from  which  all  the  motor  impulses 
immediately  proceed  to  the  muscles,  and  not  by  Cerebral  agency.     In  fact, 
the  whole  process  by  which  we  acquire  the  power  of  adapting  our  muscular 

1  Thus  in  the  Oyster  and  other  Bivalve  Mollusks,  which  have  a  complicated  digestive, 
circulating,  and  respiratory  apparatus,  food  is  brought  to  the  mouth,  fecal  matters  are  ex- 
pelled from  the  anus,  and  a  constant  current  of  water  is  made  to  sweep  over  the  respiratory 
surface,  entirely  by  ciliary  motion. 


SYMMETRY  AND    HARMONY   OF   MUSCULAR   MOVEMENTS.        911 

actions  to  the  performance  of  some  new  kind  of  movement — as  in  the  case  of  an 
infant  learning  to  walk,  a  child  learning  to  write,  an  artisan  learning  some  oc- 
cupation which  requires  nice  manipulation,  a  musical  performer  learning  a  new 
instrument,  and  so  on — is  found,  when  attentively  studied,  to  indicate  that  the 
Will  is  far  from  having  that  direct  and  immediate  control  over  the  contractions 
of  the  Muscles  which  it  is  commonly  reputed  to  possess  ;  and  that  the  operation 
really  consists  in  the  gradual  establishment  of  a  new  grouping  of  the  separate 
actions,  in  virtue  of  which  the  stimulus  of  a  Volitional  determination,  acting 
under  the  guidance  of  the  muscular  sensations,  henceforth  calls  into  contraction 
the  group  of  muscles  whose  agency  is  competent  to  carry  that  determination 
into  effect.  For  however  amenable  any  set  of  muscles  (as  those  of  the  arm  and 
hand)  may  have  become  to  the  direction  of  the  Will,  in  any  operations  which 
they  have  been  previously  accustomed  to  perform,  it  is  only  after  considerable 
practice  that  they  can  be  trained  to  any  method  of  combined  action  which  is 
entirely  new  to  them ;  and  even  if  we  attempt  to  bring  our  anatomical  know- 
ledge into  use  for  such  a  purpose,  by  mentally  fixing  upon  certain  muscles  whose 
action  we  wish  to  intensify  and  to  associate  with  those  of  others,  we  find  that 
such  a  method  of  proceeding  affords  no  assistance  whatever,  but  rather  tends  to 
impede  our  progress,  by  drawing  off  the  attention  from  the  "  guiding  sensations" 
(visual,  muscular,  &c.),  which  are  the  only  regulators  that  can  be  depended 
upon  for  determining  the  due  performance  of  the  volitional  mandate. — Hence 
we  are  led  by  these  considerations,  as  by  those  stated  in  the  preceding  paragraph, 
to  the  conclusion,  that  the  agency  which  directly  affects  the  muscles  is  of  the 
same  kind,  and  that  it  operates  under  the  same  instrumental  conditions,  what- 
ever be  the  primal  source  of  the  motor  power.  And  in  watching  the  gradual 
acquirement  of  the  capacity  for  different  kinds  of  movement,  during  the  periods 
of  Infancy  and  Childhood  in  the  Human  subject,  we  find  everything  to  confirm 
this  conclusion.  For  it  becomes  obvious  that  the  acquirement  of  Voluntary 
power  over  the  movements  of  the  limbs  is  just  as  gradual  as  it  is  over  the 
direction  of  the  thoughts  (§  839) ;  all  the  activity  of  the  body,  as  well  as  of  the 
mind,  being  in  the  first  instance  automatic,  and  the  Will  progressively  extending 
its  domination  over  the  former,  as  over  the  latter,  until  it  brings  under  its  control 
all  those  muscular  movements  which  are  not  immediately  required  for  the  con- 
servation of  the  body,  and  turns  them  to  its  own  uses.1 

2. —  Of  the  Symmetry  and  Harmony  of  Muscular  Movements. 

915.  It  might  have  been  not  unreasonably  supposed,  d  priori,  that  those 
muscles  would  have  been  most  readily  put  into  simultaneous  contraction  which 
correspond  to  each  other  on  the  two  sides  of  the  body;  in  other  words,  that 
symmetrical  movements  would  be  those  most  readily  performed.  Such,  however, 
is  by  no  means  the  case ;  for  in  many  of  our  most  familiar  actions,  we  consen- 

1  The  aptitude  which  is  acquired  by  practice,  for  the  performance  of  certain  actions  that 
were  at  first  accomplished  with  difficulty,  seems  to  result  as  much  from  a  change  which  the 
continual  repetition  of  them  occasions  in  the  Muscle,  as  in  the  habit  which  the  Nervous 
system  acquires  of  exciting  their  performance.  Thus,  almost  every  person  learning  to 
play  on  a  musical  instrument  finds  a  difficulty  in  causing  the  two  shorter  fingers  to  move 
independently  of  each  other  and  of  the  rest ;  this  is  particularly  the  case  in  regard  to 
the  ring-finger.  Any  one  may  satisfy  himself  of  the  difficulty,  by  laying  the  palm  of  the 
hand  flat  on  a  table,  and  raising  one  finger  after  the  other,  when  it  will  be  found,  that  the 
ring-finger  can  scarcely  be  lifted  without  disturbing  the  rest — evidently  from  the  difficulty 
of  detaching  the  action  of  that  portion  of  the  extensor  communis  digitorum,  by  which  the 
movement  is  produced,  from  that  of  the  remainder  of  the  muscle.  Yet  to  the  practiced 
musician,  the  command  of  the  Will  over  all  the  fingers  becomes  nearly  alike  ;  and  it  can 
scarcely  be  doubted  that  some  change  in  the  structure  of  the  muscle,  or  a  new  develop- 
ment of  its  nerve-fibres,  takes  place,  which  favors  the  isolated  operation  of  its  several 
divisions. 


912  OP   MUSCULAR   MOVEMENTS. 

taneously  exert  different  muscles  on  the  two  sides  of  the  body.  Thus,  in  ordi- 
nary walking,  we  advance  one  leg  whilst  we  push  backwards  (so  as  to  urge  the 
body  forwards)  with  the  other;  and  in  the  swinging  of  the  arms,  which  is  in  most 
persons  a  natural  part  of  this  mode  of  locomotion,  the  arms  of  the  two  sides 
move  forwards  and  backwards  alternately,  and  the  arm  of  either  side  is  advanced, 
not  with  the  leg  of  its  own  side,  but  with  that  of  the  opposite  side — any  other 
combination  being  felt  as  unnatural,  and  being  only  performed  by  a  conscious 
effort.  Now  it  is  plain  that  this  grouping  of  the  muscular  movements  arises 
out  of  its  felt  conformity  to  the  end  in  view,  and  that  it  is  regulated  by  the 
guiding  sensations  which  indicate  to  us  the  progression  and  balance  of  the  body. 
The  infant,  in  learning  to  walk,  is  prompted  by  an  instinctive  tendency  to  put 
one  foot  before  the  other,  as  may  be  noticed  at  a  very  early  period,  when  it  is 
first  held  so  as  to  feel  the  ground  with  its  feet;  and  in  attempting  to  balance 
itself  when  first  left  to  stand  alone,  it  moves  its  arms  with  a  like  intuitive 
impulse,  not  based  upon  experience.  All  that  experience  does,  in  either  case, 
is  to  give  that  precise  adjustment  to  the  muscular  action,  which  makes  it  per- 
fectly conformable  to  the  indications  afforded  by  the  muscular  sensations.  Thus, 
if  we  advance  each  arm  with  its  corresponding  leg,  we  feel  that  the  balance  of 
the  body  is  not  nearly  so  readily  maintained,  as  it  is  when  we  advance  the  arm 
with  the  leg  of  the  opposite  side;  and  thus,  without  any  design  or  voluntary  de- 
termination on  our  own  parts,  the  former  comes  to  be  our  settled  habit  of  action. 
This  kind  of  adjustment,  in  the  case  before  us,  is  by  no  means  limited  to  the 
muscles  of  the  limbs;  for  there  is  scarcely  any  muscle  of  the  trunk  or  head  that 
is  not  exerted  with  some  degree  of  consentaneous  energy,  however  unconsciously 
to  ourselves,  in  the  act  of  walking.  The  difficulty  which  would  attend  the 
voluntary  harmonization  of  all  these  separate  actions  is  remarkably  evinced  by 
the  fact,  that  no  mechanist,  however  ingenious,  has  ever  succeeded  in  construct- 
ing an  automaton  that  should  walk  like  Man;  the  alternate  shifting  of  the  centre 
of  gravity  from  one  side  to  the  other,  upon  so  small  a  base  as  the  human  foot 
affords,  simultaneously  with  its  movement  in  advance,  constituting  the  great 
difficulty  of  biped  progression.  But  all  this  adjustment  is  effected  in  our  own 
organisms,  for  us,  rather  than  by  us ;  the  act  of  harmonization,  when  once  fully 
mastered,  being  attended  with  no  effort  to  ourselves,  but  the  whole  series  of 
complex  movements  being  performed  in  obedience  to  the  simple  determination 
to  walk,  under  the  automatic  guidance  of  the  senses,  which  instantly  reveal  to 
us  any  imperfection  in  the  performance. — The  same  view  extends  itself  readily 
to  other  combinations  of  dissimilar  and  non-symmetrical  movements,  which  are 
less  natural  to  Man,  but  which  may  be  readily  acquired  artificially  if  they  all 
harmonize  in  a  common  purpose,  and  are  under  the  guidance  of  the  same  set  of 
sensations.  Thus,  the  performer  on  the  organ  uses  his  two  hands  to  execute 
different  movements  (in  very  different  positions,  it  may  be)  on  the  "manual" 
keys,  one  of  his  feet  may  be  on  the  "swell"  pedal,  and  the  other  may  be  en- 
gaged in  playing  on  the  "pedal"  keys;  but  all  these  diverse  actions  are  har- 
monized by  their  relation  to  the  same  set  of  auditory  sensations ;  and  if  the  result 
be  not  that  which  the  performer  anticipated,  an  immediate  correction  is  made. 

916.  It  would  be  easy  to  multiply  instances  of  the  same  kind,  all  illustrative 
of  the  general  principle,  that  the  facility  with  which  we  voluntarily  combine 
different  movements  is  chiefly  determined,  not  by  their  symmetrical  character, 
but  by  their  conformableness  to  a  common  end,  and  by  the  harmony  of  their  guid- 
ing sensations  with  reference  to  that  end;1  but  it  will  be  desirable  to  dwell  par- 

1  Two  simple  examples,  however,  may  be  cited,  of  the  difficulty  which  attends  the  simul- 
taneous performance  of  movements  that  are  not  harmonious.  If  we  attempt  to  elevate  one 
eyelid  whilst  we  are  depressing  the  other,  we  find  that  a  considerable  effort  is  required  to 
accomplish  the  action,  although  the  elevation  or  depression  of  both  eyelids  together  is 
performed  with  so  little  effort  that  we  are  scarcely  conscious  of  it ;  and  the  difficulty  is  in- 


SYMMETRY   AND    HARMONY   OF   MUSCULAR   MOVEMENTS.       913 

ticularly  on  the  Movements  of  the  Eye,  as  presenting  certain  points  of  peculiar 
interest,  some  of  which  have  an  important  bearing  on  Surgical  practice. — It  will 
be  recollected  that,  in  the  Human  Orbit,  six  muscles  for  the  movements  of  the 
eyeball  are  found — the  four  Recti,  and  the  two  Oblique  muscles.  The  precise 
actions  of  these  are  not  easily  established  by  experiment  on  the  lower  animals; 
for  in  all  those  which  ordinarily  maintain  the  horizontal  position,  there  is  an 
additional  muscle,  termed  the  retractor,  which  embraces  the  whole  posterior  por- 
tion of  the  globe,  and  passes  backwards  to  be  attached  to  the  bottom  of  the 
orbit.1  If  the  origin  and  insertion  of  the  four  Recti  muscles  be  examined,  how- 
ever, no  doubt  can  remain  that  each  of  them,  acting  singly,  is  capable  of  causing 
the  globe  to  revolve  in  its  own  direction — the  superior  rectus  causing  the  pupil 
to  turn  upwards — the  internal  rectus  causing  it  to  roll  towards  the  nose — and 
so  on.  A  very  easy  and  direct  application  of  the  laws  of  mechanics  will  further 
make  it  evident  to  us,  that  the  combined  action  of  any  two  of  the  Recti  muscles 
must  cause  the  pupil  to  turn  in  a  direction  intermediate  between  the  lines  of 
their  single  action ;  and  that  any  intermediate  position  may  thus  be  given  to 
the  eyeball  by  these  muscles  alone.  This  fact,  which  has  not  received  the  at- 
tention it  deserves,  leads  us  to  perceive  that  the  Oblique  muscles  must  have 
some  supplementary  function.  It  may  be  objected  that  this  is  a  theoretical 
statement  only ;  and  that  there  may  be  some  practical  obstacle  to  the  perform- 
ance of  diagonal  movements  by  the  Recti  muscles,  which  renders  the  assistance 
of  the  Obliques  essential  for  this  purpose.  But  to  this  it  may  be  replied,  that 
no  single  muscle  can  direct  the  ball  either  downwards  and  inwards,  or  upwards 
and  outwards  j  and  that,  as  we  have  good  reason  to  believe  these  movements  to 
be  effected  by  the  combination  of  the  Recti  muscles,  there  is  no  reason  why  the 
other  diagonal  movements  should  not  also  be  due  to  them. — The  most  probable 
account  of  the  functions  of  the  Oblique  muscles  of  the  eye  seems  to  be  that 
which  was  long  ago  suggested  by  John  Hunter,  and  which  has  received  con- 
firmation from  the  experiments  of  Dr.  G.  Johnson.2  It  has  been  just  shown  that 
the  action  of  the  Recti  muscles  upon  the  pupil  is  such  as  to  cause  it  to  revolve 
in  any  given  direction  ;  and  this  is  put  in  force,  not  merely  to  alter  the  range 
of  vision,  the  head  remaining  stationary,  but  also  to  keep  the  range  of  vision 
the  same,  and  to  cause  the  images  of  tfee  objects  upon  which  our  gaze  is  fixed 
still  to  fall  upon  the  same  parts  of  the  retinae,  by  maintaining  the  position  of 
the  eyes  when  the  head  is  moved  upwards,  downwards,  from  side  to  side,  or  in 
any  intermediate  direction.  But  these  muscles  are  not  able  to  rotate  the  eyeball 
upon  its  antero-posterior  axis ;  and  such  rotation  is  manifestly  necessary  to  pre- 
serve the  fixed  position  of  the  eyeball,  and  consequently  to  keep  the  image  of 

creased  if  we  half  shut  both  eyes,  and  then  try  to  close  one  and  to  open  the  other.  So  if 
we  try  to  move  our  two  hands,  as  if  they  were  simultaneously  winding  cord  in  opposite  direc- 
tions upon  two  reels  placed  in  front  of  us,  we  shall  find  ourselves  unable  to  do  so  without 
a  constant  exercise  of  the  attention,  and  even  then  but  slowly  and  with  difficulty ;  although 
the  very  same  movements  may  be  separately  performed,  or  a  movement  of  both  hands  in 
the  same  direction,  with  the  greatest  facility. 

1  This  muscle  is  most  developed  in  Ruminating  animals,  which,  during  their  whole  time 
of  feeding,  carry  their  heads  in  a  dependent  position.     In  most  Carnivorous  animals,  instead 
of  the  complete  hollow  muscular  cone  (the  base  inclosing  the  eyeball,  whilst  the  apex  sur- 
rounds the  optic  nerve),  which  we  find  in  the  Ruminants,  there  are  four  distinct  strips, 
almost  resembling  a  second  set  of  recti  muscles,  but  deep-seated,  and  inserted  into  the 
posterior  instead  of  the  anterior  portion  of  the  globe.     It  is  obvious  that  the  actions  of 
these  must  greatly  affect  the  results  of  any  operations  which  we  may  perform  upon  the 
other  muscles  of  the  Orbit ;  and,  as  it  is  impossible  to  divide  the  former,  without  completely 
separating  the  eye  from  its  attachments,  we  have  no  means  of  correcting  such  results,  but 
by  reasoning  alone.     Experiments  upon  animals  of  the  order  Quadrumana,  most  nearly 
allied  to  Man,  would  be  more  satisfactory ;  as  in  them,  the  retractor  muscle  is  almost  or 
entirely  absent. 

2  "Cyclopaedia  of  Anatomy  and  Physiology,"  vol.  iii.  p.  790. 

58 


914  OF   MUSCULAR   MOVEMENTS. 

the  object  under  survey  upon  the  same  part  of  the  retina,  when  the  head  is 
inclined  sideways,  or  bowed  towards  one  shoulder  and  then  towards  the  other. 
It  appears,  from  the  experiments  of  Dr.  Gr.  Johnson,  that  the  action  of  the 
Oblique  muscles  is  exactly  adapted  to  produce  such  a  rotation ;  the  Inferior 
oblique,  in  its  contraction,  causing  the  eyeball  to  move  upon  its  antero-poste- 
rior  axis,  in  such  a  manner  that  a  piece  of  paper,  placed  at  the  outer  margin  of 
the  cornea,  passes  downwards  and  then  inwards  towards  the  nose ;  and  the 
Superior  oblique  eifecting  precisely  the  reverse  action,  the  paper  at  the  outer 
margin  of  the  cornea  passing  first  upwards  and  then  inwards.  There  was  not 
the  slightest  appearance,  in  these  experiments,  of  elevation,  depression,  abduc- 
tion, or  adduction  of  the  cornea,  as  a  result  of  the  action  of  the  Oblique  muscles ; 
all  these  movements  being  attributable  to  the  Recti  alone.1 

917.  On  studying  the  Voluntary  movements  of  the  Eyeballs,  we  are  led  to 
perceive  that  they  are  not  so  much  symmetrical  as  harmonious;  that  is  to  say, 
the  corresponding  muscles  on  the  two  sides  are  rarely  in  action  at  once  j  whilst 
such  a  harmony  or  consent  exists  between  the  actions  of  the  muscles  of  the  two 
orbits,  that  they  work  to  one  common  purpose,  namely,  the  direction  of  both 
eyes  towards  the  required  object.  They  may  be  arranged  under  two  groups  : 
the  first  comprising  those  which  are  alike  harmonious  and  symmetrical ;  the 
second  including  those  which  are  harmonious  but  not  symmetrical.  To  the 
first  group  belong  the  following  :  1.  Both  eyeballs  are  elevated  by  the  contrac- 
tion of  the  two  Superior  Recti. — 2.  Both  eyeballs  are  depressed  by  the  conjoint 
action  of  the  Inferior  Recti  muscles. — 3.  Both  are  drawn  directly  inwards  or 
inwards  and  downwards,  as  when  we  look  at  an  object  placed  on  or  near  the 
nose ;  this  movement  is  effected  by  the  action  of  the  Internal  Recti  of  the  two 
sides,  with  or  without  the  Inferior  Recti.  It  is  evidently  symmetrical,  but  might 
seem  at  first  sight  not  to  be  harmonious,  because  the  eyes  do  not  move  together 
towards  one  side  or  the  other  ;  it  is,  however,  really  harmonious,  since  their 
axes  are  directed  towards  the  same  point.3 — Now  it  is  to  be  observed,  with  re- 
gard to  these  movements,  that  we  can  never  effect  them  in  antagonism  with  each 
other,  or  with  those  of  other  muscles.  We  cannot,  for  example,  raise  one  eye 
and  depress  the  other ;  nor  can  we  raise  or  depress  one  eye,  when  we  adduct  or 
abduct  the  other.  The  explanation  of  this  will  be  found  in  the  fact  that  we 
can  never,  by  so  doing,  direct  the  eyes  to  the  same  point. — The  harmonious  but 
unsymmetrical  movements,  forming  the  second  class,  are  those  in  which  the 
Internal  and  External  Recti  of  the  two  sides  are  made  to  act  together,  either 
alone,  or  in  conjunction  with  the  Superior  and  Inferior  Recti.  They  are  as 
follows :  4.  One  eye  is  made  to  revolve  directly  inwards,  by  the  action  of  its 
Internal  Rectus,  whilst  the  other  is  turned  outwards  by  the  action  of  its  External 
Rectus. — 5.  One  eye  is  made  to  revolve  upwards  and  inwards,  by  the  conjoint 
action  of  the  Superior  and  Internal  Recti ;  the  other,  upwards  and  outwards,  by 
the  conjoint  action  of  the  Superior  and  External  Recti. — 6.  One  eye  is  made  to 

1  The  Author  has  been  informed  by  his  friend  Mr.  Bowman  that  he  has  met  with  two 
cases  of  double  vision,  in  which  the  defect  was  not  experienced  when  the  head  was  held 
erect  or  turned  upon  its  vertical  axis,  but  only  when  it  was  inclined  to  the  one  shoulder  or 
the  other.     Such  a  peculiarity  is  readily  explained  on  the  above  hypothesis,  by  the  suppo- 
sition that  one  or  both  of  the  oblique  muscles  of  one  eye  was  paralyzed,  so  that  the  normal 
rotation  was  not  performed  on  that  side. 

2  Some  persons  can  effect  this  voluntarily  to  a  greater  extent  than  others;  but  even  then, 
they  can  only  accomplish  it  by  fixing  the  gaze  upon  some  object  situated  between  the  eyes ; 
and  cannot  call  the  adductor  muscles  into  combined  action  in  perfect  darkness,  or  if  the 
lids  be  closed.     Even  those  who  have  the  least  power  of  effecting  this  extreme  convergence 
by  at  once  directing  the  eyes  towards  a  very  near  object,  can  accomplish  it  by  looking  at 
an  object  placed  at  a  moderate  distance,  and  gradually  bringing  this  nearer  to  the  nose, 
keeping  the  eyes  steadily  fixed  upon  it.     The  unwonted  character  of  the  movement  is 
shown  in  this — that  it  can  only  be  maintained,  even  for  a  short  time,  by  a  strong  effort, 
producing  a  sense  of  fatigue. 


SYMMETRY  AND    HARMONY   OF   MUSCULAR   MOVEMENTS.       915 

revolve  downwards  and  inwards,  by  the  conjoint  action  of  the  Inferior  and  In- 
ternal Recti ;  the  other,  downwards  and  outwards,  by  the  conjoint  action  of  the 
Inferior  and  External  Recti. — In  these  movements,  two  different  muscles,  the 
External  and  Internal  Recti,  are  called  into  action  on  the  two  sides,  with  or, with- 
out the  superior  and  inferior  Recti ;  but  they  are  so  employed  for  the  purpose 
of  directing  the  axes  of  the  eyes  towards  the  same  point ;  and  although,  as  just 
noticed,  we  can  put  the  two  Internal  Recti  in  action  together,  we  cannot  volun- 
tarily cause  the  two  External  Recti  to  contract  together,  it  not  being  possible 
that  any  object  should  be  in  such  a  position  as  to  require  this  action  for  the  direc^ 
tion  of  the  axes  of  the  eyes  towards  it. 

918.  The  greater  number  of  the  foregoing  movements  may  be  performed 
even  unconsciously  to  ourselves,  in  obedience  to  a  voluntary  determination  to 
keep  the  direction  of  the  eyes  fixed,  instead  of  to  give  motion  to  the  eyeballs. 
Thus,  if  we  gaze  steadily  at  an  object  in  front  of  us,  and  then  depress  the  head 
forwards  on  its  transverse  axis,  the  eyeballs  roll  upwards  upon  their  transverse 
axes  (1)  by  the  action  of  the  Superior  Recti,  without  our  being  aware  of  it;  so 
if,  while  still  maintaining  the  same  fixed  gaze,  we  raise  the  head  into  the  vertical 
position  and  then  depress  it  backwards,  the  eyeballs  are  rolled  downwards  (2) 
by  the  action  of  the  Inferior  Recti;  if,  under  the  same  conditions,  the  head  be 
made  to  rotate  on  its  vertical  axis  from  side  to  side,  the  eyeballs  will  be  made 
to  roll  on  their  vertical  axes  in  the  contrary  direction,  by  the  External  and 
Internal  Recti  (4)  of  the  two  sides  respectively ;  so  by  causing  the  head  to 
move  obliquely  in  the  opposite  directions,  the  oblique  movements  (5  and  6)  of 
the  eyeballs  are  made  to  take  place  by  the  continued  fixation  of  the  vision  upon 
the  same  object.     To  these  we  have  to  add  one  more  action,  which  cannot  be 
called  forth  in  any  other  mode ;  namely,  that  rotation  of  the  two  eyes  upon 
their  antero-posterior  axes  which  takes  place,  probably  by  the  instrumentality 
of  the  oblique  muscles,  whem  we  incline  the  head  to  one  side  or  the  other  by 
rotating  it  upon  its  antero-posterior  axis  (§916).     In  all  these  movements,  as 
in  the  preceding,  the  Will  directs  the  result;  and  there  is  no  other  difference 
between  them,  than  that  which  arises  out  of  our  consciousness  of  a  change  in 
the  one  case,  and  our  unconsciousness   in  the  other. — The  truly  Involuntary 
movements  of  the  eyeballs,  however,  are  performed  under  very  different  condi- 
tions ;  there  being  here  no  purposive  direction  or  fixation  of  the  gaze ;  and  the 
muscular  contractions  not  being  determined  by  visual  sensations,  but  being 
called  forth  by  nerve-force  excited  in  some  remote  part.     Of  this  we  have  an 
example  in  the  normal  revolution  of  both  eyes  upwards  and  inwards,  which 
takes  place  in  the  acts  of  coughing,  sneezing,  winking,  &c. ;  but  many  more 
abnormal  movements  of  the  eyeballs,  in  which  there  is  neither  harmony  nor 
symmetry,  present  themselves  in  convulsive  diseases. 

919.  It  is  a  condition  of  single  and  distinct  vision,  that  the  usual  axes  of  the 
eyes  should  be  directed  towards  the  object,  in  order  that  its  picture  should  be 
thrown  upon  the  parts  of  the  two  retinae  which  are   accustomed  to  act  together 
(§  886);  and  that  this  direction  is  afforded  by  the  visual  sensations  which 
govern  the  muscular  movements,  the  result  of  these  merely  .being  determined 
by  the  Will,  seems  sufficiently  obvious  from  the  considerations  now  stated.     The 
following  circumstances,  however,  afford  additional  confirmation  of  this  doctrine. 
— It  is  well  known  that,  in  children  born  blind,  the  movements  are  not  harmo- 
nious ;  they  are  frequently  very  far  from  being  so,  in  cases  of  congenital  cata- 
ract, where  a  considerable  amount  of  light  is  evidently  admitted,  but  where  no 
distinct  image  can  be  formed;  and  in  such  cases,  the  movements  are  most  har- 
monious where  the  object  is  bright  or  luminous,  and  more  vivid  impressions  are 
therefore  made  upon  the  retinae.     It  is  no  objection  to  this  doctrine  to  say,  that 
persons  who  have  become  blind  may  still  move  their  eyes  in  an  harmonious 
manner ;  since,  the  habit  of  the  association  of  particular  movements  having  been 


916  OP   MUSCULAR   MOVEMENTS. 

once  acquired,  the  guidance  of  the  muscles  may  be  effected  by  sensations 
derived  from  themselves,  in  the  manner  in  which  it  takes  place  in  the  laryngeal 
movements  of  the  deaf  and  dumb ;  and,  as  a  matter  of  fact,  a  want  of  consent 
may  often  be  observed  where  the  blindness  is  total.  The  peculiar  vacant 
appearance,  which  may  be  noticed  in  the  countenances  of  persons,  completely 
deprived  of  sight  by  amaurotic  or  other  affections,  which  do  not  alter  the"  ex- 
ternal aspect  of  the  eyes,  seems  to  result  from  this — that  their  axes  are  parallel, 
as  if  the  individual  were  looking  into  distant  space,  instead  of  presenting  that 
slight  convergence  which  must  always  exist  between  them  when  the  eyes  are 
fixed  upon  a  definite  object.  This  convergence,  which  is,  of  ^course,  regulated 
by  the  Internal  Recti,  varies  in  degree  according  to  the  distance  of  the  object; 
and  it  is  astonishing  how  minute  an  alteration  in  the  axes  of  the  eyes  is  per- 
ceptible to  a  person  observing  them.  For  instance,  A  sees  the  eyes  of  B 
directed  towards  his  face,  but  he  perceives  that  B  is  not  looking  at  him ;  he 
knows  this  by  a  sort  of  intuitive  interpretation  of  the  fact,  that  his  face  is  not 
the  point  of  convergence  of  B's  eyes.  But  if  B,  who  might  have  been  pre- 
viously looking  at  something  nearer  or  more  remote  than  A's  face,  fix  his  gaze 
upon  the  latter,  so  that  the  degree  of  the  convergence  of  the  axes  is  altered, 
without  the  general  direction  of  the  eyes  being  in  the  least  affected,  the  change 
is  at  once  perceived  by  the  person  so  regarded ;  and  the  eyes  of  the  two  then 
meet. 

920.  The  physiological  principles  which  have  now  been  stated  have  an  im- 
portant application  in  the  treatment  of  Strabismus  by  operation ;  a  practice 
whose  frequent  want  of  success  is  due  in  great  part  to  the  injudicious  selection 
of  cases,  and  to  the  wrong  measures  pursued. — The  degree  in  which  habit 
accustoms  parts  of  the  retinae  that  did  not  originally  correspond,  to  work 
together  harmoniously,  is  remarkably  shown  by  the  fact,  that  patients  who  have 
been  long  affected  with  Convergent  Strabismus,  and  who  see  equally  well  with 
both  eyes  (as  many  do),  are  not  troubled  with  double  vision.  On  the  other 
hand,  when  a  person  whose  eyes  look  straight  before  him,  is  the  subject  of  a 
disorder  which  renders  their  motions  in  any  degree  irregular,  he  is  at  once 
affected  with  double  vision ;  and  the  same  has  been  frequently  noticed  as  an 
immediate  result  of  the  successful  operation  for  the  cure  of  strabismus,  where 
vision  is  good  in  both  eyes.  Although  the  images  were  previously  formed  on 
parts  of  the  retinae  which  were  very  far  from  corresponding  with  each  other, 
yet  no  sooner  is  the  position  of  the  eyes  rectified  (so  that  the  relation  between 
the  situation  of  the  images  is  the  same  as  it  would  be  in  a  sound  eye),  than  the 
patient  sees  double.  Now  in  these  cases  the  difficulty  very  speedily  diminishes, 
and  the  patient  soon  learns  to  see  single.  That  there  is  a  greater  tendency  to 
consent  between  the  images,  however,  when  they  are  formed  upon  the  parts  of 
the  two  retinae  which  normally  correspond,  may  be  freely  admitted ;  and  this 
seems  to  be  a  principle  of  some  importance  in  determining  the  readjustment  of 
the  eyes,  after  the  operation  for  Strabismus.  This  readjustment  is  not  always 
immediate  j  for  after  the  muscle  has  been  freely  divided,  the  eye  often  remains 
somewhat  inverted  for  a  few  days,  gradually  acquiring  its  straight  position.  The 
Author  has  known  one  case,  in  which,  after  such  a  degree  of  temporary  inver- 
sion as  seemed  to  render  the  success  of  the  operation  very  doubtful,  eversion 
actually  took  place  for  a  short  time  to  a  considerable  extent :  after  which  the 
axes  became  parallel,  and  have  remained  so  ever  since. — Another  argument, 
derived  from  the  results  of  this  operation,  in  favor  of  the  consensual  movement 
being  chiefly  regulated  by  the  correspondence  in  the  seats  of  the  impressions  on 
the  two  retinae,  is,  that  it  is  much  more  successful  in  those  cases  in  which  the 
sight  of  the  most  displaced  eye  is  good,  than  in  those  in  which  (as  not  unfre- 
quently  happens  from  long  disuse)  it  is  much  impaired.  In  cases  of  the  latter 
class,  the  cure  is  seldom  complete.  There  is  another  curious  fact,  which  may  be 


ENERGY   AND   RAPIDITY   OF   MUSCULAR   CONTRACTION.         917 

adverted  to  in  reference  to  this  subject :  Strabismus  not  unfrequently  arises 
from  the  presence  of  an  opaque  spot  on  the  centre  of  the  cornea,  which  prevents 
the  formation  of  any  images  on  the  retina,  except  by  the  oblique  rays;  and 
nature  seems  to  endeavor  (so  to  speak)  to  repair  the  mischief,  by  causing  the 
eye  to  assume  the  position  most  favorable  for  the  reception  of  these.1 

3. — Energy  and  Rapidity  of  Muscular  Contraction. 

921.  The  energy  of  Muscular  contraction  is,  of  course,  to  be  most  remarka- 
bly observed  in  those  instances  in  which  the  continual  exercise  of  particular 

1  In  reference  to  this  subject,  the  Author  would  add  that  he  is  well  convinced,  from 
repeated  observation,  that  those  Surgeons  are  in  the  right  who  have  maintained  that,  in  a 
large  proportion  of  cases,  strabismus  is  caused  by  an  affection  of  both  sets  of  muscles  or 
nerves,  and  not  of  one  only ;  and  that  it  then  requires,  for  its  perfect  cure,  the  division  of 
the  corresponding  muscle  on  both  sides.  Cases  will  be  frequently  met  with,  in  which  this 
is  evident ;  the  two  eyes  being  employed  to  nearly  the  same  extent,  and  the  patient  giving 
to  both  a  slight  inward  direction,  when  desired  to  look  straight  forwards.  In  general, 
however,  one  eye  usually  looks  straight  forwards,  whilst  the  other  is  greatly  inverted ; 
and  the  sight  of  the  inverted  eye  is  frequently  affected  to  a  considerable  degree  by  disuse ; 
so  that,  when  the  patient  voluntarily  rotates  it  into  its  proper  axis,  his  vision  with  it  is  far 
from  being  distinct.  Some  Surgeons  have  maintained  that  the  inverted  eye  is  usually  the  only 
one  in  fault,  and  consider  that  the  division  of  the  tendon  of  its  Internal  Rectus  is  sufficient 
for  the  cure.  They  would  even  divide  its  other  tendons,  if  the  parallelism  be  not  restored, 
rather  than  touch  the  other  eye.  The  Author  is  himself  satisfied,  however,  that  the  restric- 
tion of  the  abnormal  state  to  a  single  eye  is  the  exception,  and  not  the  rule,  in  all  but 
very  slight  cases  of  strabismus ;  and  to  this  opinion  he  is  led  both  by  the  consideration  of 
the  mode  in  which  strabismus  first  takes  place,  and  by  the  results  of  the  operations  which 
have  come  under  his  notice.  If  the  eyes  of  an  infant  affected  with  cerebral  disease  be 
watched,  there  will  frequently  be  observed  in  them  very  irregular  movements ;  the  axes 
of  the  two  being  sometimes  extremely  convergent,  and  then  very  divergent.  This  irregu- 
larity is  rarely  or  never  seen  to  be  confined  to  one  eye.  Now,  in  a  large  proportion  of 
cases  of  Strabismus,  the  malady  is  a  consequence  of  some  cerebral  affection  during  infancy 
or  childhood,  which  we  can  scarcely  suppose  to  have  affected  one  eye  only.  Again,  in  other 
instances  we  find  the  Strabismus  to  have  resulted  from  the  constant  direction  of  the  eyes 
to  very  near  objects,  as  in  short-sighted  persons ;  and  here,  too,  the  cause  manifestly  affects 
both. — Now  it  is  easy  to  understand,  why  one  eye  of  the  patient  should  appear  to  be  in  its 
natural  position,  whilst  the  other  is  greatly  inverted.  The  cause  of  strabismus  usually 
affects  the  two  eyes  somewhat  unequally,  so  that  one  is  much  more  inverted  than  the 
other.  We  will  call  the  least  inverted  eye  A,  and  the  other  B.  In  the  ordinary  acts  of 
vision,  the  patient  will  make  most  use  of  the  least  inverted  eye,  A,  because  he  can  most 
readily  look  straight  forwards  or  outwards  with  it ;  but  to  bring  it  into  the  axis,  or  to 
rotate  it  outwards,  necessitates  a  still  more  decided  inversion  of  B.  This  remains  the  posi- 
tion of  things — the  patient  usually  looking  straight  forwards  with  A,  which  is  the  eye  con- 
stantly employed  for  the  purposes  of  vision — and  frequently  almost  burying  under  the 
inner  canthus  the  other  eye.  B,  the  vision  in  which  is  of  very  little  use  to  him.  When, 
therefore,  the  tendon  of  the  internal  rectus  of  B  is  divided,  the  relative  position  of  the  two 
is  not  entirely  rectified.  Sometimes  it  appears  to  be  so  for  a  time  ;  but  the  strabismus 
then  begins  to  return,  and  it  can  only  be  checked  by  division  of  the  tendon  of  the  other 
eye,  A ;  after  which,  the  cure  is  generally  complete  and  permanent.  That  it  has  not  been 
so,  in  many  of  the  patients  on  whom  operations  have  been  performed,  the  Author  attributes, 
without  the  slightest  doubt  in  his  own  mind,  to  the  neglect  of  the  second  operation.  As 
just  now  stated,  the  sight  of  the  most  inverted  eye  is  frequently  very  imperfect ;  indeed 
it  is  sometimes  impaired  to  such  an  extent,  that  the  patients  speak  of  it  as  entirely  use- 
less. That  this  impairment  results  in  part  from  disuse  merely,  seems  very  evident  from 
the  great  improvement  which  often  succeeds  the  rectification  of  the  axes.  The  Author 
cannot  help  thinking  it  probable,  however,  that  the  same  cause  which  produced  the  dis- 
tortion of  the  eye  may,  in  some  instances  at  least,  have  affected  the  Optic  nerve,  as  well 
as  the  motor  nerves  of  the  orbit ;  and  this  idea  seems  borne  out  by  the  asserted  restora- 
tion of  sight,  in  certain  cases  of  Amaurosis,  by  division  of  one  or  more  tendons,  where  no 
Strabismus  previously  existed  (See  Adams  "  On  Muscular  Amaurosis"). — A  valuable  me- 
moir on  the  operation  for  Strabismus,  founded  on  the  results  of  about  1000  cases,  will  be 
found  in  the  "  Philadelphia  Medical  Examiner,"  vol.  vii.,  and  an  abstract  of  it  in  the 
"Brit,  and  For.  Med.-Chir.  Review,"  July,  1852,  p.  262. 


918  OF    MUSCULAR    MOVEMENTS. 

parts  has  occasioned  an  increased  determination  of  blood  towards  them,  and  in 
consequence  a  permanent  augmentation  in  their  bulk.  This  has  been  the  case, 
for  example,  with  persons  who  have  gained  their  livelihood  by  exhibiting  feats 
of  strength.  Much  will,  of  course,  depend  on  the  mechanically  advantageous 
application  of  muscular  power;  and  in  this  manner,  effects  maybe  produced,  even 
by  persons  of  ordinary  strength,  which  would  not  have  been  thought  credible. 
In  lifting  a  heavy  weight  in  each  hand,  for  example,  a  person  who  keeps  his 
back  perfectly  rigid,  so  as  to  throw  the  pressure  vertically  upon  the  pelvis,  and 
only  uses  the  powerful  extensors  of  the  thigh  and  calf,  by  straightening  the 
^nees  (previously  somewhat  flexed),  and  bringing  the  leg  to  a  right  angle  with 
the  foot,  will  have  a  great  advantage  over  one  who  uses  his  lumbar  muscles  for 
the  purpose.  A  still  greater  advantage  will  be  gained,  by  throwing  the  weight 
more  directly  upon  the  loins,  by  means  of  a  sort  of  girdle,  shaped  so  as  to  rest 
upon  the  top  of  the  sacrum  and  the  ridges  of  the  ilia ;  and  by  pressing  with 
the  hands  upon  a  frame,  so  arranged  as  to  bring  the  muscles  of  the  arms  to  the 
assistance  of  those  of  the  legs  :  in  this  manner  a  single  man,  of  ordinary 
strength,  may  raise  a  weight  of  2000  Ibs. ;  whilst  few,  who  are  unaccustomed  to 
such  exertions,  can  lift  more  than  300  Ibs.  in  the  ordinary  mode.  A  man  of 
great  natural  strength,  however,  has  been  known  to  lift  800  Ibs.  with  his  hands ; 
and  the  same  individual  performed  several  other  curious  feats  of  strength,  which 
seem  deserving  of  being  here  noticed  :  "  1.  By  the  strength  of  his  fingers,  he 
rolled  up  a  very  large  and  strong  pewter  dish.  2.  He  broke  several  short  and 
strong  pieces  of  tobacco-pipe,  with  the  force  of  his  middle  finger,  having  laid 
them  on  the  first  and  third  finger.  3.  Having  thrust  in  under  his  garter  the  bowl 
of  a  strong  tobacco-pipe,  his  legs  being  bent,  he  broke  it  to  pieces  by  the  tendons 
of  his  hams,  without  altering  the  bending  of  the  knee.  4.  He  broke  such 
another  bowl  between  his  first  and  second  fingers,  by  pressing  them  together 
sideways.  5.  He  lifted  a  table  six  feet  long,  which  had  half  a  hundred-weight 
hanging  at  the  end  of  it,  with  his  teeth,  and  held  it  in  that  position  for  a  con- 
siderable time.  It  is  true,  the  feet  of  the  table  rested  against  his  knees ;  but, 
as  the  length  of  the  table  was  much  greater  than  its  height,  that  performance 
required  a  great  strength  to  be  exerted  by  the  muscles  of  his  loins,  neck,  and 
jaws.  6.  He  took  an  iron  kitchen  poker,  about  a  yard  long,  and  three  inches 
in  circumference,  and,  holding  it  in  his  right  hand,  he  struck  it  on  his  bare  left 
arm  between  the  elbow  and  the  wrist,  till  he  bent  the  poker  nearly  to  a  right 
angle.  7.  He  took  such  another  poker,  and,  holding  the  ends  of  it  in  his 
hands,  and  the  middle  of  it  against  the  back  of  his  neck,  he  brought  both  ends 
of  it  together  before  him  j  and,  what  was  yet  more  difficult,  he  pulled  it  straight 
again."1  Haller  mentions  an  instance  of  a  man  who  could  raise  a  weight  of 
300  Ibs.  by  the  action  of  the  elevator  muscles  of  his  jaw :  and  that  of  a  slen- 
der girl,  affected  with  tetanic  spasm,  in  whom  the  extensor  muscles  of  the  back, 
in  the  state  of  tonic  contraction  or  opisthotonos,  resisted  a  weight  of  800  Ibs., 
laid  on  the  abdomen  with  the  absurd  intention  of  straightening  the  body.  It 
is  to  be  recollected  that  the  mechanical  application  of  the  power  developed  by 

1  "  Desaguliers'  Philosophy,"  vol.  ii. — The  energy  of  muscular  contraction  appears  to 
be  greater  in  Insects,  in  proportion  to  their  size,  than  it  is  in  any  other  animals.  Thus  a 
Flea  has  been  known  to  leap  sixty  times  its  own  length,  and  to  move  as  many  times  its 
own  weight.  The  short-limbed  Beetles,  however,  which  inhabit  the  ground,  manifest  the 
greatest  degree  of  muscular  power.  The  Lucanus  cervus  (Stag  Beetle)  has  been  known  to 
gnaw  a  hole  of  an  inch  in  diameter,  in  the  side  of  an  iron  canister  in  which  it  had  been 
confined.  The  Geotropes  stercorarius  (Dung  or  shard-born  Beetle)  can  support  uninjured, 
and  even  elevate,  a  weight  equal  to  at  least  500  times  that  of  its  body.  And  a  small 
Carabus  has  been  seen  to  draw  a  weight  of  85  grains  (about  24  times  that  of  its  body) 
up  a  plane  of  25° ;  and  a  weight  of  125  grains  (36  times  that  of  its  body)  up  a  plane  of  5°  ; 
and  in  both  these  instances  the  friction  was  considerable,  the  weights  being  simply  laid 
upon  a  piece  of  paper,  to  which  the  insect  was  attached  by  a  string. 


ENERGY   AND   RAPIDITY   OF    MUSCULAR   CONTRACTION.          919 

muscular  contraction  to  the  movement  of  the  body,  is  very  commonly  disad- 
vantageous as  regards  force  ;  being  designed  to  cause  the  part  moved  to  pass 
over  a  much  greater  space  than  that  through  which  the  muscle  contracts.  Thus 
the  Temporal  muscle  is  attached  to  the  lower  jaw,  at  about  one-third  of  the  dis- 
tance between  the  condyle  and  the  incisors  ;  so  that  a  shortening  of  the  muscle 
to  the  amount  of  half  an  inch  will  draw  up  the  front  of  the  jaw  through  an 
inch  and  a  half;  but  a  power  of  900  Ibs.  applied  by  the  muscle  would  be 
required  to  raise  300  Ibs.  bearing  on  the  incisors.  In  the  case  of  the  forearm 
and  leg,  the  disproportion  is  much  greater ;  the  points  of  attachment  of  the 
muscles,  by  which  the  knee  and  elbow-joints  are  flexed  and  extended,  being 
much  closer  to  the  fulcrum,  in  comparison  with  the  distance  of  the  points  on 
which  the  resistance  bears. 

922.  The  rapidity  of  the  changes  of  position  of  the  component  particles  of 
muscular  fibres  may,  as  Dr.  Alison  justly  remarks,1  be  estimated,  though  it 
can  hardly  be  conceived,  from  various  well-known  facts.  The  pulsations  of  the 
heart  can  sometimes  be  distinctly  numbered  in  children,  at  more  than  200  in 
the  minute ;  and  as  each  contraction  of  the  ventricles  occupies  only  one-third  of 
the  time  of  the  whole  pulsation,  it  must  be  accomplished  in  l-600th  of  a  minute, 
or  1-1  Oth  of  a  second.  Again,  it  is  certain  that,  by  the  movements  of  the  tongue 
and  other  organs  of  speech,  1500  letters  can  be  distinctly  pronounced  by  some 
persons  in  a  minute ;  each  of  these  must  require  a  separate  contraction  of  mus- 
cular fibres ;  and  the  production  and  cessation  of  each  of  the  sounds  imply  that 
each  separate  contraction  must  be  followed  by  a  relaxation  of  equal  length;  each 
contraction,  therefore,  must  have  been  effected  in  l-3000th  part  of  a  minute,  or 
in  150th  of  a  second.  Haller  calculated  that,  in  the  limbs  of  a  dog  at  full  speed, 
muscular  contractions  must  take  place  in  less  than  the  l-200th  of  a  second,  for 
many  minutes  at  least  in  succession. — All  these  instances,  however,  are  thrown 
into  the  shade,  by  those  which  may  be  drawn  from  the  class  of  Insects.  The 
rapidity  of  the  vibrations  of  the  wings  may  be  estimated  from  the  musical  tone 
which  they  produce ;  it  being  easily  ascertained  by  experiments,  what  number 
of  vibrations  are  required  to  produce  any  note  in  the  scale  (§  908).  From  these 
data,  it  appears  to  be  the  necessary  result,  that  the  wings  of  many  Insects  strike 
the  air  many  hundred,  or  even  many  thousand,  times  in  every  second. — The 
minute  precision  with  which  the  degree  of  muscular  contraction  can  be  adapted 
to  the  designed  effect,  is  in  no  instance  more  remarkable  than  in  the  Glottis. 
The  musical  pitch  of  the  tones  produced  by  it  is  regulated  by  the  degree  of 
tension  of  the  chordae  vocoles,  which  are  possessed  of  a  very  considerable  degree 
of  elasticity  (§  928).  According  to  the  observations  of  Miiller,2  the  average 
length  of  these,  in  the  male,  in  a  state  of  repose,  is  about  73-100ths  of  an  inch; 
whilst,  in  the  state  of  greatest  tension  it  is  about  93-100ths;  the  difference  being 
therefore  20-100ths,  or  one-fifth  of  an  inch  :  in  the  female  glottis,  the  average 
dimensions  are  about  51-100ths,  and  63-100ths  respectively;  the  difference  being 
thus  about  one-eighth  of  an  inch.  Now  the  natural  compass  of  the  voice,  in 
most  persons  who  have  cultivated  the  vocal  organ,  may  be  stated  at  about  two 
octaves,  or  24  semitones.  Within  each  semitone,  a  singer  of  ordinary  capability 
could  produce  at  least  ten  distinct  intervals ;  so  that  of  the  total  number,  240  is 
a  very  moderate  estimate.  There  must,  therefore,  be  at  least  240  different  states 
of  tension  of  the  vocal  cords,  every  one  of  which  is  producible  by  the  will,  with- 
out any  previous  trial ;  and  the  whole  variation  in  the  length  of  the  cords  being 
not  more  than  one-fifth  of  an  inch  even  in  man,  the  variation  required  to  pass 
from  one  interval  to  another  will  not  be  more  than  l-1200th  of  an  inch.  And 

1  "  Cyclopaedia  of  Anatomy  and  Physiology,"  Art.  "Contractility." 

2  "Elements  of  Physiology,"  Baly's  translation,  p.  1018. 


920  OP   MUSCULAR    MOVEMENTS. 

yet  this  estimate  is  much  below  that  which  might  be  truly  made  from  the  per- 
formances of  a  practised  vocalist.1 

4. —  Of  the  Influence  of  Expectant  Attention  on  Muscular  Movements, 

923.  There  is  a  very  curious  group  of  involuntary  muscular  movements,  not 
yet  specially  considered,  which  may  be  ranked  under  the  general  category  of 
ideo-motor  actions ;  being  induced  by  the  state  of  expectant  attention,  in  which 
the  mind  is  fully  possessed  with  the  idea  that  a  certain  action  will  take  place, 
and  is  eagerly  looking  out  for  its  occurrence.  Such  movements  are  well  known 
to  occur  in  the  muscles  connected  with  the  organic  functions,  and  are  among 
the  means  by  which  important  modifications  are  produced  in  those  functions  by 
the  direction  of  the  mind  to  them.  Thus,  as  Dr.  Holland  has  remarked,  "the 
action  of  the  heart  is  often  quickened  or  otherwise  disturbed  by  the  mere  centring 
the  consciousness  upon  it,  without  any  emotion  or  anxiety.  On  occasions  where 
its  beats  are  audible,  observation  will  give  proof  of  this,  or  the  physician  can 
very  often  infer  it  while  feeling  the  pulse;  and  where  there  is  liability  to  irregular 
pulsation,  such  action  is  seemingly  brought  on,  or  increased,  by  the  eifort  of  atten- 
tion, even  though  no  obvious  emotion  be  present."  "  The  same  may  be  said  of 
the  parts  concerned  in  respiration.  If  this  act  be  expressly  made  the  subject  of 
consciousness,  it  will  be  felt  to  undergo  some  change ;  generally  to  be  retarded 
at  first,  and  afterwards  quickened."  "  The  act  of  swallowing,  again,  becomes 
manifestly  embarrassed,  and  is  made  more  difficult  by  the  attention  fixed  upon  it 
when  the  morsel  to  be  swallowed  comes  into  contact  with  the  part."3  And  there 
can  be  no  doubt  that  the  movements  of  the  lower  part  of  the  alimentary  canal 
are  capable  of  being  affected  in  a  similar  manner,  since  we  may  frequently  trace 
the  rapid  descent  of  the  faecal  mass  into  the  rectum,  when  we  expect  to  be  shortly 
able  to  discharge  it ;  and  it  is  in  great  part  in  this  mode  that  habit  operates,  in 
producing  a  readiness  for  defecation  at  particular  times,  and  that  bread-pills  and 
other  supposititious  purgatives  unload  the  bowels.3 

1  It  is  said  that  the  celebrated  Made.  Mara  was  able  to  sound  100  different  intervals 
between  each  tone.     The  compass  of  her  voice  was  at  least  three  octaves,  or  21  tones ; 
so  that  the  total  number  of  intervals  was  2100,  all  comprised  within  an  extreme  variation 
of  one-eighth  of  an  inch ;  so  that  it  might  be  said  that  she  was-  able  to  determine  the  con- 
tractions of  her  vocal  muscles  to  nearly  the  seventeen-thousandth  of  an  inch. 

2  See  Dr.  Holland's  "Chapters  on  Mental  Physiology,"  pp.  16-19. 

3  The  Author  may  mention  the  two  following  cases,  which  have  fallen  within  his  own 
knowledge,  as  curious  illustrations  of  the  influence  of  mental  states  upon  the  movements  of 
the  alimentary  canal. — The  first  of  these  occurred  in  the  person  of  a  literary  man,  of  a  some- 
what hypochondriacal  temperament,  who  had  been  troubled  with  continual  costiveness,  for 
which  he  had  been  accustomed  to  take  an  aperient  pill  daily.     Finding  that  this  ceased  to 
have  its  usual  effect,  and  being  feaful  of  increasing  his  regular  dose,  he  applied  for  advice 
to  a  practitioner,  who,  having  had  former  experience  of  what  mental  agency  alone  would  do, 
determined  to  try  its  effect  in  this  instance.     Seating  his  patient  before  him,  with  the  abdo- 
men uncovered,  he  desired  him  to  fix  his  attention  intently  upon  his  abdominal  sensations, 
and  assured  him  that  in  a  short  time  he  was  quite  certain  that  he  would  begin  to  feel  a 
movement  in  his  bowels,  which  would  end  in  a  copious  evacuation.     He  himself  did  nothing 
but  look  steadily  at  his  patient,  with  an  air  of  great  determination  and  confidence,  and 
point  his  finger  at  the  abdomen,  moving  it  along  the  arch  of  the  colon,  and  (as  it  were)  in 
the  course  of  the  convolutions  of  the  small  intestines,  so  as  to  aid  the  patient  in  fixing  his 
attention  upon  them.     In  a  short  time,  the  expected  movements  were  felt,  and  a  copious 
evacuation  soon  followed ;  and  for  some  time  afterwards,  the  bowels  continued  to  act  freely 
without  medicine. — In  the  other  case,  a  Lecturer  at  a  public  Institution  was  seized  with  a 
strong  impulse  to  defecation  during  his  lecture ;  and  was  greatly  inconvenienced  by  the 
effort  necessary  to  restrain  it.     Before  every  subsequent  lecture  in  the  same  place,  the 
same  impulse  returned  upon  him,  notwithstanding  that  he  might  have  previously  unloaded 
his  bowels  elsewhere.     In  this  case,  there  was  obviously  a  state  of  apprehension  combined 
with  the  simple  anticipation ;  but  the  influence  of  the  latter  is  shown  by  the  fact,  that  in 
no  other  place  did  this  individual  experience  the  impulse  in  question  under  the  like  cir- 
cumstances. 


EXPECTANT   ATTENTION  —  MUSCULAR   MOVEMENTS.  921 

924.  But  it  is  with  the  involuntary  movements  produced  by  the  same  agency 
in  the  muscles  ordinarily  accounted  voluntary,  that  we  are  at  present  especially 
concerned.  This  is  a  very  curious  subject  of  inquiry,  and  one  to  which  ade- 
quate attention  has  scarcely  yet  been  given ;  the  phenomena  which  are  referable 
to  the  principle  of  action  just  enunciated,  having  been  very  commonly  explained 
by  the  agency  of  some  other  force.  .Thus,  if  a  button  or  ring  be  suspended 
from  the  end  of  the  finger  or  thumb,  in  such  a  position  that,  when  slightly 
oscillating,  it  shall  strike  against  a  glass  tumbler,  it  has  been  affirmed  by  many 
who  have  made  the  experiment,  that  the  button  continues  to  swing  with  great 
regularity,  striking  the  glass  at  tolerably  regular  intervals,  until  it  has  sounded 
the  hour  of  the  day,  after  which  it  ceases  for  a  time  to  swing  far  enough  to 
make  another  stroke.  This  certainly  does  come  to  pass,  in  many  instances, 
without  any  intention  on  the  part  of  the  performer;  who  may,  in  fact,  be  doing 
all  in  his  power  to  keep  his  hand  perfectly  stationary.  Now  it  is  impossible, 
by  any  voluntary  effort,  to  keep  the  hand  absolutely  still,  for  any  length  of 
time,  in  the  position  required;  an  involuntary  tremulousness  is  always  observ- 
able in  the  suspended  body;  and  if  the  attention  be  fixed  upon  the  part,  with 
the  expectation  that  the  vibrations  will  take  a  determinate  direction,  they  are 
very  likely  to  do  so.1  Their  persistence  in  this  direction,  however,  only  takes 
place  so  long  as  they  are  guided  by  the  visual  sensations ;  a  fact  which  at  once 
indicates  the  real  spring  of  their  performance.  When  the  performer  is  im- 
pressed with  the  conviction  that  the  hour  will  be  thus  indicated,  the  result  is 
very  likely  to  happen ;  and  when  it  has  once  occurred,  his  confidence  is  suffi- 
ciently established  to  make  its  recurrence  a  matter  of  tolerable  certainty.  On 
the  other  hand,  the  experiment  seldom  succeeds  with  sceptical  subjects;  the 
expectant  idea  not  having  in  them  the  requisite  potency.  That  it  is  through 
the  mind  that  these  movements  are  regulated,  however  involuntarily,  appears 
evident  from  these  two  considerations :  first,  that  if  the  performer  be  entirely 
ignorant  of  the  hour,  the  strokes  on  the  glass  do  not  indicate  its  number,  except 
by  a  casual  coincidence;  and  second,  that  the  division  of  the  entire  period  of 
the  earth's  rotation  into  twenty-four  hours,  and  the  very  nomenclature  of  these 
hours,  being  entirely  arbitrary  and  conventional,  cannot  be  imagined  to  ope- 
rate in  any  other  mode.2  These  phenomena,  in  which  no  hypothetical  "odylic" 
or  other  concealed  agency  can  be  reasonably  supposed  to  operate,  are  here 
alluded  to  only  for  the  sake  of  illustrating  those  next  to  be  described,  which 
have  been  imagined  to  prove  the  existence  of  a  new  force  in  Nature. — If  "a 
fragment  of  anything,  of  any  shape/'  be  suspended  from  the  end  of  the  fore- 
finger or  thumb,  and  the  attention  be  intently  fixed  upon  it,  regular  oscillations 
will  be  frequently  seen  to  take  place  in  it;  and  if  changes  of  various  kinds  be 
made  in  the  conditions  of  the  experiment,  by  placing  bodies  of  different  sorts 
beneath  the  pendulum,  or  by  the  contact  of  different  persons  or  things  with  the 
person  of  the  suspender,  corresponding  changes  in  the  direction  of  the  move- 
ments will  very  commonly  take  place.3  Now  this  will  occur,  notwithstanding 
the  strong  desire  of  the  experimenter  to  maintain  a  complete  immobility  in  the 
suspending  finger;  but  it  is  very  easily  proved  that  the  movements  are  guided 

1  This  was  long  since  pointed  out  by  M.  Chevreuil,  who  investigated  the  subject  in  a 
truly  philosophic  spirit.     See  his  letter  to  M.  Ampere,  in  the  "  Dublin  Journal  of  Medical 
and  Chemical  Science,"  vol.  iv. 

2  For  instance,  the  button  which  strikes  eleven  at  night  in  London,  should  strike  twenty- 
three  in  Rome,  where  the  cycle  of  hours  is  continued  through  the  whole  twenty-four  hours ; 
and  if  an  Act  of  Parliament  were  to  introduce  the  Italian  horary  arrangement  into  this 
country,  all  the  swinging  buttons  in  her  Majesty's  dominions  would  have  to  add  twelve  to 
their  number  of  post-meridian  strokes ;  all  which  would  doubtless  come  to  pass,  if  the 
experimenters'  faith  in  the  result  were  sufficiently  strong. 

9  See  Dr.  H.  Mayo  on  "  The  Truths  contained  in  Popular  Superstitions,"  3d  edition, 
Letter  xii. 


922  OF    MUSCULAR   MOVEMENTS. 

by  his  visual  sensations,  and  that  the  impulse  to  them  is  entirely  derived  from 
his  expectation  of  a  given  result.  For,  if  he  close  his  eyes,  or  withdraw  them 
from  the  vibrating  body,  its  oscillations  (as  in  the  previous  case)  immediately 
lose  their  constancy;  manifestly  proving  that  the  influence  which  directs  them 
acts  through  his  consciousness.  And,  again,  if  he  be  ignorant  of  the  change 
which  is  made  in  the  conditions  of  the  experiment,  and  should  expect  or  guess 
something  different  from  that  which  really  exists,  the  movement  will  be  in  ac- 
cordance with  his  idea,  not  with  the  reality.1 — Thus,  then,  we  have  here  a  most 
distinct  proof  that  a  state  of  mind  exists,  which  is  neither  volitional  nor  emo- 
tional, but  which  consists  in  the  complete  engrossment  of  the  attention  by  a 
fixed  idea,  whereby  definite  muscular  movements  are  produced,  in  spite  of  a 
determined  exertion  of  the  Will.  The  Will  is  concerned,  however,  in  the  in- 
duction of  the  mental  state  in  question,  by  the  fixation  of  the  attention  on  the 
oscillating  body;  and  it  is  only  in  those  individuals  who  possess  the  power  of 
voluntary  abstraction  (§  823)  to  a  considerable  extent  that  the  experiment  is 
likely  to  succeed.  It  is  scarcely  necessary  to  add,  that  as  faith  in  its  results  is 
essential  to  their  production,  those  who  are  acquainted  with  the  mode  in  which 
they  are  really  brought  about,  are  not  likely  to  be  good  subjects  for  it. 

925.  It  is  doubtless  on  the  very  same  physiological  principle,  that  we  are  to 
explain  the  mysterious  phenomena  of  the  "Divining-Rod,"  which  have  been 
accepted  as  true,  or  rejected  as  altogether  fabulous,  according  to  the  previous 
habits  of  thought  of  those  who  have  given  their  attention  to  the  subject.  Now 
that  the  end  of  a  hazel-fork,  whose  limbs  are  grasped  firmly  in  the  hands  of  a 
person  whose  good  faith  can  scarcely  be  doubted,  frequently  points  upwards  or 
downwards  without  any  intentional  direction  on  his  part,  and  often  thus  moves 
when  there  is  metal  or  water  beneath  the  surface  of  the  ground  at  or  near  the 
spot,  is  a  fact  which  is  vouched  for  by  such  testimony  that  we  have  scarcely  a 
right  to  reject  it;  and  when  we  come  to  examine  into  the  conditions  of  the  oc- 
currence, we  shall  find  that  they  are  such  as  justify  us  in  attributing  it  to  a 
state  of  expectant  attention,  which  (as  we  have  seen)  is  fully  competent  to  induce 
muscular  movement.  For,  in  the  first  place,  as  not  above  one  individual  in 
forty,  even  in  the  localities  where  the  virtues  of  the  divining-rod  are  still  held 
as  an  article  of  faith,  is  found  to  succeed  in  the  performance  of  this  experiment, 
it  is  obvious  that  the  agency,  whatever  be  its  nature,  which  produces  the  de- 
flections, must  operate  by  affecting  the  holder  of  the  rod,  and  not  by  attracting 
or  repelling  the  rod  itself.  And  when  experiments  are  carefully  made  with  the 
view  of  determining  the  nature  of  this  agency,  they  are  found  to  indicate  most 
clearly  that  the  state  of  expectant  attention,  induced  by  the  anticipation  of 
certain  results,  is  fully  competent  to  produce  them.  For  the  mere  act  of  hold- 

1  A  most  remarkable  and  convincing  exemplification  of  this  fact  is  afforded  by  Dr. 
Henry  Madden' s  experiments  with  Mr.  Rutter's  "Magnetometer,"  at  Brighton,  as  detailed 
in  the  "Lancet"  for  Nov.  15,  1851. — Dr.  Madden  had  satisfied  himself,  in  the  first  in- 
stance, that  the  vibrations  of  the  suspended  body  were  affected  by  the  reception,  into  his 
other  hand,  of  homoeopathic  globules,  whose  differences  of  composition  were  indicated  by 
corresponding  changes  in  the  direction  of  the  oscillations.  But  having  been  led  to  re- 
examine  the  question,  and  to  apply  that  test  which  he  ought  to  have  employed  from  the 
first — namely,  to  have  various  globules  put  into  his  hand,  without  being  himself  made 
aware  of  their  composition — he  found  that  the  results  entirely  lost  their  previous  con- 
stancy, which  was  thus  evidently  due  to  his  expectation  of  a  particular  movement  in  each 
case.  It  is  a  manifestation  of  the  very  imperfect  analysis  which  is  commonly  made  of 
such  phenomena,  that,  from  the  moment  when  they  are  found  referable  to  a  physiological 
principle,  instead  of  demonstrating  (as  they  were  at  first  supposed  to  do)  the  existence  of 
a  new  force,  they  seem  to  lose  all  their  interest  for  those  who  had  previously  watched 
them  with  eagerness,  and  to  be  set  down  as  illusory,  or  as  the  product  of  the  "imagina- 
tion;" notwithstanding  that  they  are  as  real  in  the  one  case  as  in  the  other,  and  are  not 
in  any  degree  less  curious  and  interesting  when  considered  under  the  former  aspect,  than 
when  viewed  in  the  latter. 


EXPECTANT   ATTENTION  —  MUSCULAR    MOVEMENTS.  923 

ing  the  rod  for  some  time  in  the  required  position,  and  of  attending  to  its  indi- 
cations, is  sufficient  to  produce  a  tendency  to  spasmodic  contraction  in  the 
grasping  muscles,  notwithstanding  a  strong  effort  of  the  will  to  the  contrary ; 
and  when,  by  such  contractions,  the  limbs  of  the  fork  are  made  to  approximate 
towards  or  to  separate  from  each  other,  the  point  of  the  fork  will  be  caused  to 
move  either  upwards  or  downwards,  according  to  the  position  in  which  it  is 
held.  If,  when  the  muscles  have  this  tendency  to  contract,  occasioned  by  their 
continued  restraint  in  one  position,  the  mind  be  possessed  with  the  expectation 
that  a  certain  movement  will  ensue,  that  movement  will  actually  take  place, 
even  though  a  strong  effort  may  be  made  by  the  Will  to  prevent  any  change  in 
the  condition  of  the  muscles.  And  a  sufficient  ground  for  such  expectation 
exists,  on  the  part  of  those  who  are  possessed  with  the  idea  of  the  peculiar 
powers  of  the  divining-rod,  in  the  belief,  or  even  in  the  surmise,  that  water  or 
metal  may  be  beneath  particular  points  of  the  surface  over  which  they  pass.1— 

1  This  was  admitted  even  by  Dr.  H.  Mayo,  notwithstanding  his  belief  in  the  existence 
of  an  "  Od-force,"  governing  the  movements  of  the  divining-rod.  For  he  found,  in  the 
course  of  his  experiments,  that  when  his  "diviner"  knew  which  way  he  expected  the  fork 
to  move,  it  invariably  answered  his  expectations ;  but  when  he  had  the  man  blindfolded, 
the  results  were  uncertain  and  contradictory.  Hence  he  became  certain  that  several  of 
those  in  whose  hands  the  divining-rod  moves,  set  it  in  motion,  and  direct  its  motion  (how- 
ever unintentionally  and  unconsciously)  by  the  pressure  of  their  fingers,  and  by  carrying 
their  hands  nearer  to  or  apart  from  each  other.  (See  his  Letters  "  On  the  Truths  con- 
tained in  Popular  Superstitions,"  Letter  i.) — The  following  statement  of  the  results 
obtained  by  a  very  intelligent  friend  of  the  Author,  who  took  up  the  inquiry  some  years 
ago,  with  a  strong  prepossession  (derived  from  the  assurances  of  men  of  high  scientific  note) 
in  favor  of  the  reality  of  the  supposed  influence,  but  yet  with  a  desire  to  investigate  the 
whole  matter  carefully  and  philosophically  for  himself,  will  serve  as  a  complete  illustration 
of  the  doctrine  enunciated  above.  Having  duly  provided  himself  with  a  hazel-fork,  he  set 
out  upon  a  survey  of  the  neighborhood  in  which  he  happened  to  be  staying  on  a  visit ;  this 
district  was  one  known  to  be  traversed  by  mineral  veins,  with  the  direction  of  some  of 
which  he  was  acquainted.  With  his  "  divining-rod"  in  his  hand,  and  with  his  attention 
closely  fixed  upon  his  instrument  of  research,  he  walked  forth  upon  his  experimental  tour; 
and  it  was  not  long  before,  to  his  great  satisfaction,  he  observed  the  point  of  the  fork  to 
be  in  motion,  at  the  very  spot  where  he  knew  that  he  was  crossing  a  metallic  lode.  For 
many  less  cautious  investigators,  this  would  have  been  enough ;  but  it  served  only  to 
satisfy  this  gentleman  that  he  was  a  favorable  subject  for  the  trial,  and  to  stimulate  him 
to  further  inquiry.  Proceeding  in  his  walk,  and  still  holding  his  fork  secundum  artem,  he 
frequently  noticed  its  point  in  motion,  and  made  a  record  of  the  localities  in  which  this 
occurred.  He  repeated  these  trials  on  several  consecutive  days,  until  he  had  pretty 
thoroughly  examined  the  neighborhood,  going  over  some  parts  of  it  several  times.  When 
he  came  to  compare  and  analyze  the  results,  he  found  that  there  was  by  no  means  a 
satisfactory  accordance  amongst  them ;  for  there  were  many  spots  over  which  the  rod  had 
moved  on  one  occasion,  at  which  it  had  been  obstinately  stationary  on  others,  and  vice 
versa  ;  so  that  the  constancy  of  a  physical  agency  seemed  altogether  wanting.  Further, 
he  found  that,  whilst  some  of  the  spots  over  which  the  rod  had  moved  were  those  known 
to  be  traversed  by  mineral  veins,  there  were  many  others  in  which  its  indications  had  been 
no  less  positive,  but  in  which  those  familiar  with  the  mining  geology  of  the  neighborhood 
were  well  assured  that  no  veins  existed.  On  the  other  hand,  the  rod  had  remained  motion- 
less at  many  points  where  it  ought  to  have  moved,  if  its  direction  had  been  affected  by  any 
kind  of  terrestrial  emanation.  These  facts  led  the  experimenter  to  a  strong  suspicion  that 
the  cause  existed  in  himself  alone  ;  and  carrying  out  his  experiments  still  further,  he 
ascertained  that  he  could  not  hold  the  fork  in  his  hand  for  many  minutes  consecutively, 
concentrating  his  attention  fixedly  upon  it,  without  an  alteration  in  the  direction  of  its 
point,  in  consequence  of  an  involuntary  though  almost  imperceptible  movement  of  his 
hands  ;  so  that  in  the  greater  number  of  instances  in  which  the  rod  exhibited  motion,  the 
phenomenon  was  clearly  attributable  to  this  cause,  and  it  was  a  matter  of  pure  accident 
whether  the  movement  took  place  over  a  mineral  vein,  or  over  a  blank  spot.  But  further 
he  ascertained  on  a  comparison  of  his  results,  that  the  movement  took  place  more  fre- 
quently where  he  knew  or  suspected  the  existence  of  mineral  veins,  than  in  other  situa- 
tions ;  and  thus  he  came,  without  any  knowledge  of  the  theory  of  expectant  attention,  to  the 
practical  conclusion  that  the  actions  of  his  nerves  and  muscles  were  in  great  degree  re- 
gulated by  the  ideas  which  possessed  his  mind. 


924  OF   MUSCULAR   MOVEMENTS. 

Until,  therefore,  it  shall  have  been  proved  by.  an  extended  course  of  carefully 
conducted  experiments,  that  this  mode  of  explanation  is  inadequate  to  account 
for  the  phenomena  in  question,  all  that  is  genuine  in  what  is  at  present  known 
may  be  set  down  to  the  category  of  Ideo-motor  actions,  or  reflex  actions  of  the 
(Jerebrum  (§  683). 

926.  To  this  same  category  are  doubtless  to  be  referred  a  large  number  of 
those  actions  of  Mesmeric  "  subjects"  which  have  been  considered  by  some  as 
most  unequivocal  indications  of  the  existence  of  an  agency  sui  generis,  whilst 
by  others  they  have  been  regarded  as  the  results  of  intentional  deception.  Now 
many  of  them  are  of  a  kind  which  the  Will  could  not  feign,  being  violent  con- 
vulsive movements,  such  as  no  voluntary  effort  could  produce ;  but  the  Mes- 
meric "  subject"  being  previously  possessed  with  the  expectation  that  certain 
results  will  follow  certain  actions  (as,  for  instance,  that  convulsive  movements 
will  be  brought  on  by  touching  a  piece  of  mesmerized  metal),  and  the  whole 
nervous  power  being  concentrated,  as  it  were,  upon  the  performance,  the  move- 
ments follow  when  the  subject  believes  the  conditions  to  have  been  fulfilled, 
whether  they  have  been,  or  not.  These  facts  were  most  completely  established 
by  the  commission  appointed  to  investigate  the  pretensions  of  Mesmer  himself; 
and  whilst  they  demonstrate  the  unreality  of  the  supposed  mesmeric  influence 
(so  far,  at  least,  as  this  class  of  phenomena  is  concerned),  they  also  prove  the 
position  here  contended  for,  namely,  the  sufficiency  of  the  state  of  expectant 
attention,  in  those  whose  minds  can  be  completely  possessed  by  it,  to  produce 
effects  of  the  same  nature  with  those  which  are  induced  in  Hysterical  subjects 
by  emotional  excitement.1 


CHAPTER    XVII. 

OF   THE   VOICE   AND    SPEECH. 

1. —  Of  the  Larynx,  and  its  Actions. 

927.  THE  sounds  produced  by  the  organ  of  Voice  constitute  the  most  import- 
ant means  of  communication  between  Man  and  his  fellows;  and  the  power  of 
Speech  has,  therefore,  a  primary  influence,  as  well  on  his  physical  condition  as 
on  the  development  of  his  mental  faculties.  In  order  to  understand  the  nature 
of  this  organ  as  a  generator  of  Sound,  it  is  requisite  to  inquire,  in  the  first 
instance,  into  the  sources  from  which  sounds  at  all  corresponding  to  the  Human 
voice  are  elsewhere  obtained.  It  is  necessary  to  bear  in  mind  that  Vocal 
sounds,  and  speech  or  articulate  language,  are  two  things  entirely  different;  and 
that  the  former  may  be  produced  in  great  perfection,  where  there  is  no  capa- 
bility for  the  latter.  Hence  we  should  at  once  infer  that  the  instrument  for  the 
production  of  vocal  sounds  was  distinct  from  that  by  which  these  sounds  are 
modified  into  articulate  speech;  and  this  we  easily  discover  to  be  the  case,  the 
voice  being  unquestionably  produced  in  the  larynx,  whilst  the  modifications  of 
it  by  which  language  is  formed  are  effected  for  the  most  part  in  the  oral  cavity. 
— The  structure  and  functions  of  the  former,  then,  first  claim  our  attention. 

1  On  the  whole  of  this  subject,  the  Author  has  the  satisfaction  of  referring  to  the  essay 
on  "The  Effects  of  Attention  on  Bodily  Organs,"  in  Dr.  Holland's  "Chapters  on  Mental 
Physiology,"  as  showing  the  essential  coincidence  between  the  opinions  of  this  distin- 
guished Physician,  and  those  at  which  he  had  himself  arrived  by  independent  inquiry. 


OP   THE   LARYNX,   AND   ITS   ACTIONS. 
Fig.  231. 


925 


External  and  Sectional  views  of  the  Larynx:  A  n  B,  the  cricoid  cartilage;  E  c  a,  the  thyroid  cartilage;  a, 
its  upper  horn ;  c,  its  lower  horn,  where  it  is  articulated  with  the  cricoid;  F,  the  arytenoid  cartilage;  E,  F,  the 
vocal  ligament ;  AK,  crico-thyroideus  muscle ;  F  e  m,  thyro-arytenoideus  muscle;  x  e,  cricc-arytenoideus  lateralis ; 
s,  transverse  section  of  arytenoideus  transversus;  m  n,  space  between  thyroid  and  cricoid;  B  i,  projection  of 
axis  of  articulation  of  arytenoid  with  thyroid. 

928.  It  will  be  remembered  that  the  Trachea  is  surmounted  by  a  stout  car- 
tilaginous annulus,  termed  the  Cricoid  cartilage ;  which  serves  as  a  foundation 
for  the  superjacent  mechanism.  This  is  embraced  (as  it  were)  by  the  Thyroid, 
which  is  articulated  to  its  sides  by  its  lower  horns,  round  the  extremities  of 
which  it  may  be  regarded  as  turning,  as  on  a  pivot.  In  this  manner  the  lower 
front  border  of  the  thyroid  cartilage,  which  is  ordinarily  separated  by  a  small 
interval  from  the  upper  margin  of  the  cricoid,  may  be  made  to  approach  it  or 
recede  from  it ;  as  any  one  may  easily  ascertain  by  placing  his  finger  against  the 
little  depression  which  may  be  readily  felt  externally,  and  observing  its  changes 
of  size,  whilst  a  range  of  different  tones  is  sounded j  for  it  will  then  be  noticed  that 
the  higher  the  note  the  more  the  two  cartilages  are  made  to  approximate,  whilst 
they  separate  in  proportion  to  the  depth  of  the  tones.1  Upon  the  upper  surface 
of  the  back  of  the  cricoid,  are  seated  the  two  small  Arytenoid  cartilages ;  these 
are  fixed  in  one  direction  by  a  bundle  of  strong  ligaments,  which  tie  them  to 
the  back  of  the  cricoid;  but  they  have  some  power  of  moving  in  other  directions, 
upon  a  kind  of  articulating  surface.  The  direction  of  the  surface,  and  the  mode 
in  which  these  cartilages  are  otherwise  attached,  cause  their  movement  to  be  a 
sort  of  rotation  in  a  plane  which  is  nearly  horizontal  but  partly  downwards ;  so 
that  their  vertical  planes  may  be  made  to  separate  from  each  other,  and  at  the 
same  time  to  assume  a  slanting  position.  This  change  of  place  will  be  better 
understood,  when  the  action  of  the  muscles  is  described.  To  the  summit  of  the 
arytenoid  cartilages  are  attached  the  chordae  vocales  or  Vocal  Ligaments,  which 
stretch  across  to  the  front  of  the  thyroid  cartilage ;  and  it  is  upon  the  condition 
and  relative  situation  of  these  ligaments  that  their  action  depends.  It  is  evi- 
dent that  they  may  be  rendered  more  or  less  tense,  by  the  movement  of  the 

1  In  making  this  observation,  it  is  necessary  to  put  out  of  view  the  general  movement 
to  the  larynx  itself,  which  the  finger  must  be  made  to  follow  up  and  down. 


926 


OF   THE   VOICE   AND    SPEECH. 


Thyroid  cartilage  just  described ;  being  tightened  by  the  depression  of  its  front 
upon  the  Cricoid  cartilage,  and  slackened  by  its  elevation.  On  the  other  hand, 
they  may  be  brought  into  more  or  less  close  apposition,  by  the  movement  of  the 
Arytenoid  cartilages;  being  made  to  approximate  nearly,  or  to  recede  in  such  a 


Fig.  232. 


Fig.  233. 


Bird's-eye  view  of  Larynx  from  above  :  G  E  H, 
the  thyroid  cartilage,  embracing  the  ring  of  the 
cricoid  r  u  X  to,  and  turning  upon  the  axis  x  z, 
which  passes  through  the  lower  horns,  c,  Fig. 
231.  N  F,  N  F,  the  arytenoid  cartilages,  connected 
by  the  arytenoideus  transversus.  T  v,  T  v,  the 
vocal  ligaments.  N  x,  the  right  crico-arytenoideus 
lateralis  (the  left  being  removed).  V  k  f,  the  left 
thyro-arytenoideus  (the  right  being  removed). 
H  Z,  N  I,  the  crico-arytenoidei  postici ;  B,  u,  the 
crico-arytenoid  ligaments. 


Posterior  view  of  larynx,  and  part  of  tra- 
chea, dissected  to  show  the  muscles,  a.  Right 
arytenoid  cartilage,  t,  t.  Posterior  margins 
of  thyroid  cartilage,  c.  Back  of  cricoid  car- 
tilage, h.  Oshyoides.  e.  Epiglottis,  b.  Left 
posterior  crico-arytenoid  muscle,  s.  Arytenoid 
muscle.  I.  Fibrous  membrane  at  back  of  tra- 
chea, with  the  glands  lying  in  it.  n.  Muscular 
fibres  of  the  trachea,  r.  Cartilaginous  rings 
of  trachea. 


manner  as  to  cause  the  rima  glottidis  to  assume  the  form  of  a  narrow  V,  by  the 
revolution  of  these  cartilages. — We  shall  now  inquire  into  the  actions  of  the 
muscles  upon  the  several  parts  of  this  apparatus ;  and  first  into  those  of  the 
larynx  alone. 

929.  The  depression  of  the  front  of  the  thyroid  cartilage,  and  the  consequent 
tension  of  the  vocal  Ligaments,  is  occasioned  by  the  conjoint  action  of  the 
Crico-thyroidei  on  both  sides  j  and  the  chief  antagonists  to  these  are  the  Thyro- 
arytenoidei,  which  draw  the  front  of  the  thyroid  back  towards  the  arytenoid 
cartilages,  and  thus  relax  the  vocal  ligaments.  These  two  pairs  of  muscles  may 
be  regarded  as  the  principal  governors  of  the  pitch  of  the  notes,  which,  as  we 
shall  hereafter  see,  is  almost  entirely  regulated  by  the  tension  of  the  ligaments ; 
their  action  is  assisted,  however,  by  that  of  other  muscles  presently  to  be  men- 
tioned.— The  arytenoid  cartilages  are  made  to  diverge  from  each  other,  by  means 
of  the  Crico-arytenoidei  postici  of  the  two  sides,  which  proceed  from  their  outer 
corners,  and  turned  somewhat  round  the  edge  of  the  Cricoid,  to  be  attached  to 


OF   THE   LARYNX,   AND   ITS   ACTIONS.  927 

the  lower  part  of  its  back ;  their  action  is  to  draw  the  outer  corners  backwards 
and  downwards,  so  that  the  points  to  which  the  vocal  ligaments  are  attached, 
are  separated  from  one  another,  and  the  rima  glottidis  is  thrown  open.  This 
will  be  at  once  seen  from  the  preceding  diagram,  in  which  the  direction  of  trac- 
tion of  the  several  muscles  is  laid  down. — The  action  of  these  muscles  is  partly 
antagonized  by  that  of  the  Crico-arytenoidei  laterales,  which  run  forwards  and 


Part  of  Fig.  232  enlarged,  to  show  the  Direction  of  the,  Muscular  JFbrce^which  act  on  the  Arytenoid  carti- 
lage :  Q  N  v  s,  the  right  Arytenoid  cartilage ;  T  v,  its  vocal  ligament ;  B  R  8,  hundle  of  ligaments  uniting  it  to 
Cricoid ;  0  P,  projection  of  its  axis  of  articulation ;  h  g,  direction  of  the  action  of  the  Thyro-arytenoideus  ;  N  X, 
direction  of  Crico-ary tenoideus  lateralis ;  N  w,  direction  of  Crico-ary tenoideus  posticus ;  N  T,  direction  of  Ary- 
tenoideus  transversus. 

downwards  from  the  outer  corners  of  the  Arytenoid  cartilages,  and  whose  action 
is  to  bring  the  anterior  points  of  the  arytenoid  cartilages  into  the  same  straight 
line,  at  the  same  time  depressing  them,  so  as  thus  to  close  the  glottis.  These 
muscles  are  assisted  by  the  Arytenoideus  transversus,  which  connects  the  pos- 
terior faces  of  the  Arytenoid  cartilages,  and  which,  by  its  contraction,  draws 
them  together.  By  the  conjoint  action,  therefore,  of  the  Crico-arytenoidei 
laterales  and  of  the  Arytenoideus  transversus,  the  whole  of  the  adjacent  faces 
of  the  Arytenoid  cartilages  will  be  pressed  together,  and  the  points  to  which 
the  vocal  ligaments  are  attached  will  be  depressed. — But  if  the  Arytenoideus 
be  put  in  action  in  conjunction  with  the  Crico-arytenoidei  postici,  the  tendency 
of  the  latter  to  separate  the  Arytenoid  cartilages  being  antagonized  by  the 
former,  its  backward  action  only  will  be  exerted ;  and  thus  it  may  be  caused  to 
aid  the  Crico-thyroidei  in  rendering  tense  the  vocal  ligaments.  .  This  action 
will  be  further  assisted  by  the  Sterno-ihyroidei,  which  tend  to  depress  the  Thy- 
roid cartilage,  by  pulling  from  a  fixed  point  below  j1  and  the  Thyro-liyoidei  will 
be  the  antagonist  of  these,  when  they  act  from  a  fixed  point  above,  the  Os 
Hyoides  being  secured  by  the  opposing  contraction  of  several  other  muscles. — 
The  respective  actions  of  these  muscles  will  be  best  comprehended  by  the  fol- 
lowing Table  : — 

1  These  are  not  usually  reckoned  among  the  principal  muscles  concerned  in  regulating 
the  voice;  but  that  they  are  so,  any  one  may  convince  himself  by  placing  his  finger 
just  above  the  sternum,  whilst  he  is  sounding  high  notes  ;  a  strong  feeling  of  muscular 
tension  is  then  at  once  perceived. 


928  OF   THE   VOICE   AND    SPEECH. 


Govern  the  Pitch  of  the  Notes. 

«   f  PUT™  TTTV  f  DePress  the  front  of  the  Thyroid  cartilage  on  the  Cri- 

I  {  s£™~o  T^IDEI     }  ......         coid'  and  stretch  the  vocal  lights;  assisted  by  the 

I      Arytenoideus  and  Crico-arytenoidei  postici. 
Elevate  the  front  of  the  Thyroid  cartilage,  and  draw 

the 


Govern  the  Aperture  of  the  Glottis. 
"S     CRICO-ARYTENOIDEI  POSTICI  ................  Open  the  Glottis. 

•§   f  CRICO-ARYTENOIDEI  LATERALES  1  f  Press  together  the  inner  edges  of  the  Ary- 

•<  \  ARYTENOIDEUS  TRANS  VERSUS      /  "    "  \     tenoid  cartilages,  and  close  the  Glottis. 

930.  The  muscles  which  stretch  or  relax  the  Yocal  ligaments  are  entirely 
concerned  in  the  production  of  Voice  ;  those  which  govern  the  aperture  of  the 
Glottis  have  important  functions  in  connection  with  the  Respiratory  actions  in 
general,  and  stand  as  guards  (so  to  speak)  at  the  entrance  to  the  lungs.  Their 
separate  actions  are  easily  made  evident.  In  the  ordinary  condition  of  rest,  it 
seems  probable  that  the  Arytenoid  cartilages  are  considerably  separated  from 
each  other  ;  so  as  to  cause  a  wide  opening  to  intervene  between  their  inner 
faces,  and  between  the  vocal  ligaments,  through  which  the  air  freely  pass*es  ; 
and  the  vocal  ligaments  are  at  the  same  time  in  a  state  of  complete  relaxation. 
—  We  can  close  the  aperture  of  the  Glottis  by  an  exertion  of  the  will,  either 
during  inspiration  or  expiration;  and  its  closure  by  an  automatic  impulse  forms 
part  of  the  acts  of  Coughing  and  Sneezing  (§  555),  besides  giving  rise  to  those 
more  prolonged  impediments  to  the  ingress  and  egress  of  air  which  have  been 
already  noticed  as  resulting  from  disordered  states  of  the  Nervous  system 
(§  849,  xvii).  With  these  actions,  the  muscles  which  regulate  the  tension  of 
the  vocal  ligaments  have  nothing  to  do  ;  and  we  have  seen  that  they  are  per- 
formed by  the  instrumentality  of  the  Pneumogastric  or  proper  Respiratory  nerve 
(§  718).  A  slight  examination  of  the  recent  Larynx  is  sufficient  to  make  it 
evident,  that  when  once  the  borders  of  the  rima  glottidis  are  brought  together 
by  muscular  action,  the  effect  of  strong  aerial  pressure  on  either  side  (whether 
produced  by  an  expulsory  blast  from  below,  or  by  a  strong  inspiratory  effort, 
occasioning  a  partial  vacuum  below,  and  consequently  an  increased  pressure 
above),  will  be  to  force  them  into  closer  apposition.  —  In  order  to  produce  a 
Vocal  sound,  it  is  not  sufficient  to  put  the  ligaments  into  a  state  of  tension  ; 
they  must  also  be  brought  nearer  to  each  other.  That  the  aperture  of  the 
glottis  is  greatly  narrcwed  during  the  production  of  sounds,  is  easily  made  evi- 
dent to  one's  self,  by  comparing  the  time  occupied  by  an  ordinary  expiration,  with 
that  required  for  the  passage  of  the  same  quantity  of  air  during  the  sustenance 
of  a  vocal  tone.  Further,  the  size  of  the  aperture  is  made  to  vary  in  accordance 
with  the  note  which  is  being  produced  ;  of  this,  too,  any  one  may  convince 
himself,  by  comparing  the  times  during  which  he  can  hold  out  a  low  and  a  high 
note  ;  from  which  it  will  appear,  that  the  aperture  of  the  glottis  is  so  much 
narrowed  in  producing  a  high  note,  as  to  permit  a  much  less  rapid  passage  of 
air  than  is  allowed  when  a  low  one  is  sounded.  This  adjustment  of  the  aperture 
to  the  tension  of  the  vocal  ligaments  is  a  necessary  condition  for  the  production 
of  a  clear  and  definite  tone.  It  further  appears  that,  in  the  narrowing  of  the 
glottis  which  is  requisite  to  bring  the  vocal  ligaments  into  the  necessary  approxi- 
mation, the  upper  points  of  the  Arytenoid  cartilages  are  caused  to  approximate, 
not  only  by  being  made  to  rotate  horizontally  towards  each  other,  but  also  by  a 


OF   THE   LARYNX,    AND   ITS   ACTIONS.  929 

degree  of  elevation ;  so  that  the  inner  faces  of  the  vocal  ligaments  are  brought 
into  parallelism  with  each  other — a  condition  which  may  be  experimentally 
shown  to  be  necessary  for  their  being  thrown  into  sonorous  vibration.  The 
muscular  movements  concerned  in  the  act  of  vocalization  appear  to  be  called 
forth  by  the  instrumentality  of  the  fibres  of  the  Spinal  Accessory  nerve  which 
are  contained  in  the  Pneumogastric  (§  719). 

931.  We  have  now  to  inquire  what  is  the  operation  of  the  Vocal  Ligaments 
in  the  production  of  sounds ;  and  in  order  to  comprehend  this,  it  is  necessary  to 
advert  to  the  conditions  under  which  tones  are  produced  by  instruments  of 
various  descriptions  having  some  analogy  with  the  Larynx.  These  are  chiefly 
of  three  kinds;  strings,  flute-pipes,  and  reeds  or  tongues. — The  Vocal  Ligaments 
were  long  ago  compared  by  Ferrein  to  vibrating  strings  ;  and  at  first  sight  there 
might  seem  a  considerable  analogy,  the  sounds  produced  by  both  being  elevated 
by  increased  tension.  This  resemblance  disappears,  however,  on  more  accurate 
comparison ;  for  it  may  be  easily  ascertained  by  experiment,  that  no  string  so 
short  as  the  vocal  ligaments  could  give  a  clear  tone,  at  all  to  be  compared  in 
depth  with  that  of  the  lowest  notes  of  the  human  voice ;  and  also,  that  the  scale 
of  changes  produced  by  increased  tension  is  fundamentally  different.  When  the 
strings  of  the  same  length,  but  of  different  tensions,  are  made  the  subject  of 
comparison,  it  is  found  that  the  number  of  vibrations  is  in  proportion  to  the 
square-roots  of  the  extending  forces.  Thus,  if  a  string  extended  by  a  given 
weight  produce  a  certain  note,  a  string  extended  by  four  times  that  weight  will 
give  a  note  in  which  the  vibrations  are  twice  as  rapid;  and  this  will  be  the 
octave  of  the  other.  If  nine  times  the  original  weight  be  employed,  the  vibra- 
tions will  be  three  times  as  rapid  as  those  of  the  fundamental  note,  producing 
the  twelfth  above  it.  Now  by  fixing  the  larynx  in  such  a  manner  that  the  vocal 
ligaments  can  be  extended  by  a  known  weight,  Mu'ller  has  ascertained  that  the 
sounds  produced  by  a  variation  of  the  extending  force  do  not  follow  the  same 
ratio ;  and  therefore  the  condition  of  these  ligaments  cannot  be  simply  that  of 
vibrating  cords.  Further,  a  cord  of  a  certain  length,  which  is  adapted  to  give 
out  a  clear  and  distinct  note,  equal  in  depth  to  the  lowest  of  the  human  voice, 
may  be  made  by  increased  tension  to  produce  all  the  superior  notes,  which,  in 
stringed  instruments,  are  ordinarily  obtained  by  shortening  the  strings.1  But 
it  does  not  follow  that  a  short  string,  which,  with  moderate  tension,  naturally 
produces  a  high  note,  should  be  able,  by  a  diminution  of  the  tension,  to  give 
out  a  deep  one ;  for,  although  this  might  be  theoretically  possible,  yet  it  cannot 
be  accomplished  in  practice ;  since  the  vibrations  became  irregular  on  account 
of  the  diminished  elasticity.3  These  considerations  are  in  themselves  sufficient 
to  destroy  the  supposed  analogy;  and  to  prove  that  the  Chordse  Vocales  cannot 
be  reduced  to  the  same  category  with  vibrating  strings. — The  next  kind  of 
instrument  with  which  some  analogy  might  be  suspected  is  the  flute-pipe,  in 
which  the  sound  is  produced  by  the  vibration  of  an  elastic  column  of  air  contained 
in  the  tube ;  and  the  pitch  of  the  note  is  determined  almost  entirely  by  the 
length  of  the  column,  although  slightly  modified  by  its  diameter,  and  by  the 
nature  of  the  embouchure  or  mouth  from  which  it  issues.  This  is  exemplified 
in  the  German  Flute,  and  in  the  English  Flute  or  Flageolet ;  in  both  of  which 

1  Thus  in  the  Piano-forte,  where  there  are  strings  for  each  note,  a  gradual  shortening 
is  seen  from  the  lowest  to  the  highest ;  and  in  the  Violin  the  change  of  tone  is  produced 
by  stopping  the  strings  with  the  finger,  so  as  to  diminish  their  acting  length. 

2  Thus  it  would  be  impossible  to  produce  good  Bass  notes  on  the  strings  of  a  Violin,  by 
diminishing  their  tension;  the  length  aiforded  by  the  Violoncello  or  Double  Bass  is  requisite. 
The  striking  difference  between  the  tone  of  the  Bass  strings  in  the  Grand  Piano-forte  'and 
the  small  upright  Piccolo  is  another  exemplification  of  the  same  principle ;  being  chiefly 
due  to  the  length  and  tension  of  the  former,  as  contrasted  with  the  shortness  and  slackness 
of  the  latter. 

59 


930  OP   THE  VOICE   AND    SPEECH. 

instruments,  the  acting  length  of  the  pipe  is  determined  by  the  interval  between 
t^e  embouchure  and  the  nearest  of  the  side  apertures ;  by  opening  or  closing 
which,  therefore,  a  modification  of  the  tone  is  produced.  In  the  Organ,  of  which 
the  greater  number  of  pipes  are  constructed  upon  this  plan,  there  is  a  distinct 
pipe  for  every  note  ;  and  their  length  increases  in  a  regular  scale.  It  is,  in 
fact,  with  flute-pipes  as  with  strings — that  a  diminution  in  length  causes  an 
increase  in  the  number  of  vibrations,  but  in  a  -simply  inverse  proportion ;  so 
that  of  two  pipes,  one  being  half  the  length  of  the  other,  the  shorter  will  give  a 
tone  which  is  the  octave  above  the  other,  the  vibrations  of  its  column  of  air 
being  twice  as  rapid.  Now  there  is  nothing  in  the  form  or  dimensions  of  the 
column  of  air  between  the  larynx  and  the  mouth,  which  can  be  conceived  to 
render  it  at  all  capable  of  such  vibrations  as  are  required  to  produce  the  tones 
of  the  Human  voice ;  though  there  is  some  doubt  whether  it  be  not  the  agent 
in  the  musical  tones  of  certain  Birds.  The  length  of  an  open  pipe  necessary  to 
give  the  lowest  Gr  of  the  ordinary  bass  voice  is  nearly  six  feet ;  and  the  condi- 
tions necessary  to  produce  the  higher  notes  from  it  are  by  no  means  those 
which  we  find  to  exist  in  the  process  of  modulating  the  human  voice. — We  now 
come  to  the  third  class  of  instruments,  in  which  sound  is  produced  by  the  vibra- 
tion of  reeds  or  tonyues ;  these  may  either  possess  elasticity  in  themselves,  or 
be  made  elastic  by  tension.  The  "  free"  reeds  of  the  Eolian,  Accordion, 
Seraphine,  Harmonium,  &c.,  are  examples  of  instruments  of  this  character,  in 
which  the  lamina  vibrates  in  a  sort  of  frame  that  allows  the  air  to  pass  out  on 
all  sides  of  it  through  a  narrow  channel,  thus  increasing  the  strength  of  the  blast : 
whilst  in  the  Hautboy,  Bassoon,  &c.,  and  in  Organ-pipes  of  similar  construction, 
the  reed  covers  an  aperture  at  the  side  of  one  end  of  a  pipe.  In  the  former 
kind,  the  sound  is  produced  by  the  vibration  of  the  tongue  alone,  and  is  regulated 
entirely  by  its  length  and  elasticity  ;  whilst  in  the  latter,  its  pitch  is  dependent 
upon  this,  conjointly  with  the  length  of  the  tube,  the  column  of  air  contained 
in  which  is  thrown  into  simultaneous  vibration.  Some  interesting  researches 
on  the  effect  produced  on  the  pitch  of  a  sound  given  by  a  reed,  through  the 
union  of  it  with  a  tube,  have  been  made  by  M.  W.  Weber;  and,  as  they  are  im- 
portant in  furnishing  data  by  which  the  real  nature  of  the  vocal  organ  may  be 
determined,  their  chief  results  will  be  here  given. — I.  The  pitch  of  a  reed  may 
be  lowered,  but  cannot  be  raised,  by  joining  it  to  a  tube.  n.  The  sinking  of 
the  pitch  of  the  reed  thus  produced  is  at  the  utmost  not  more  than  an  octave. 
in.  The  fundamental  note  of  the  reed,  thus  lowered,  may  be  raised  again  to  its 
original  pitch,  by  a  further  lengthening  of  the  tube;  and  by  a  further  increase 
is  again  lowered.  IV.  The  length  of  tube,  necessary  to  lower  the  pitch  of  the 
instrument  to  any  given  point,  depends  on  the  relation  which  exists  between 
the  frequency  of  the  vibrations  of  the  tongue  of  the  reed  and  those  of  the 
column  of  air  in  the  tube,  each  taken  separately. — From  these  data,  and  from 
those  of  the  preceding  paragraph,  it  follows  that,  if  a  wind  instrument  can,  by 
the  prolongation  of  its  tube,  be  made  to  yield  tones  of  any  depth  in  proportion 
to  the  length  of  the  tube,  it  must  be  regarded  as  a  flute-pipe ;  whilst  if  its  pitch 
can  only  be  lowered  an  octave  or  less  (the  embouchure  remaining  the  same)  by 
lengthening  the  tube,  we  may  be  certain  that  it  is  a  reed  instrument.  The 
latter  proves  to  be  the  case  in  regard  to  the  Larynx. 

982.  It  is  evident  from  the  foregoing  considerations  that  the  action  of  the 
Larynx  has  more  analogy  to  that  of  reed  instruments  than  it  has  to  that  either 
of  vibrating  strings,  or  of  flute-pipes.  There  would  seem,  at  first  sight,  to  be  a 
marked  difference  in  character,  between  the  vocal  ligaments  and  the  tongue  of 
any  reed  instrument;  but  this  difference  is  really  by  no  means  considerable. 
In  a  reed,  elasticity  is  a  property  of  the  tongue  itself,  when  fixed  at  one  end, 
the  other  vibrating  freely  ;  but  by  a  membranous  lamina,  fixed  in  the  same  man- 
ner, no  tone  would  be  produced.  If  such  a  lamina,  however,  be  made  elastic 


OF   THE   LARYNX,    AND   ITS    ACTIONS. 


931 


Fig.  235. 


by  a  moderate  degree  of  tension,  and  be  fixed  in  such  a  manner  as  to  be  advan- 
tageously acted  on  by  a  current  of  air,  it  will  give  a  distinct  tone.  It  is  ob- 
served by  Miiller,  that  membranous  tongues  made  elastic  by  tension  may  have 
either  of  three  different  forms  :  I.  That  of  a  band  extended  by  a  cord,  and  in- 
cluded between  two  firm  plates,  so  that  there  is  a  cleft  for  the  passage  of  air  on 
each  side  of  the  tongue,  n.  The  elastic  membrane  may  be  stretched  over  the 
half  or  any  portion  of  the  end  of  a  short  tube,  the  other  part  being  occupied  by  a 
solid  plate,  between  which  and  the  elastic  membrane  a  narrow  fissure  is  left.  in. 
Two  elastic  membranes  may  be  extended  across  the  mouth  of  a  short  tube,  each 
covering  a  portion  of  the  opening,  and  having  a  chink  left  open  between  them. 
— This  last  is  evidently  the  form  most  allied  to  the  Human  Glottis ;  but  it  may 
be  made  to  approximate  still  more  closely  by  prolonging  the  membranes  in  a 
direction  parallel  to  that  of  the  current  of  air,  so  that  not  merely  their  edges, 
but  their  whole  planes  shall  be  thrown  into  vibration.  Upon  this  principle,  a 
kind  of  artificial  glottis  has  been  constructed  by  Mr.  Willis ;  the  conditions  of 
action  and  the  effects  of  which  are  so 
nearly  allied  to  that  of  the  real  in- 
strument, that  the  similar  character 
of  the  two  can  scarcely  be  doubted. 
The  following  is  his  description  of  it : 
"  Let  a  wooden  pipe  be  prepared  of 
the  form  of  Fig.  235,  a,  having  a  foot, 
C,  like  that  of  an  organ-pipe,  and  an 
upper  opening,  long  and  narrow,  as  at 
B,  with  a  point,  A,  rising  at  one  end 
of  it.  If  a  piece  of  leather,  or  still 
better,  of  sheet  India-rubber  be  dou- 
bled round  this  point,  and  secured  by 
being  bound  round  the  pipe  at  D,  with 
strong  thread,  as  in  Fig.  235,  6,  it 
will  give  us  an  artificial  glottis  with 
its  upper  edges  G  H,  which  may  be 
made  to  vibrate  or  not,  at  pleasure,  by 
inclining  the  planes  of  the  edges.  A 
couple  of  pieces  of  cork,  E,  F,  may 

be  glued  to  the  corners,  to  make  them  more  manageable.  From  this  machine, 
various  notes  may  be  obtained  by  stretching  the  edges  in  the  direction  of  their 
length  G  H ;  the  notes  rising  in  pitch  with  the  increased  tension,  although  the 
length  of  the  vibrating  edge  is  increased.  It  is  true  that  a  scale  of  notes  equal 
in  extent  to  that  of  the  human  voice  cannot  be  obtained  from  edges  of  leather ; 
but  this  scale  is  much  greater  in  India-rubber  than  in  leather ;  and  the  elas- 
ticity of  them  both  is  so  much  inferior  to  that  of  the  vocal  ligaments,  that  we 
may  readily  infer  that  the  greater  scale  of  the  latter  is  due  to  its  greater  elastic 
powers."  By  other  experimenters,  the  tissue  forming  the  middle  coat  of  the 
arteries  has  been  used  for  this  purpose,  in  the  moist  state,  with  great  success ; 
with  this  the  tissue  of  the  vocal  ligaments  is  nearly  identical.  It  is  worthy  of 
remark,  that  in  all  such  experiments,  it  is  found  that  the  two  membranes  may 
be  thrown  into  vibration,  when  inclined  towards  each  other  in  various  degrees, 
or  even  when  they  are  in  parallel  planes,  and  their  edges  only  approximate ; 
but  that  the  least  inclination  from  each  other  (which  is  the  position  the  vocal 
ligaments  have  during  the  ordinary  state  of  the  glottis,  §  930),  completely  pre- 
vents any  sonorous  vibrations  from  being  produced. 

933.  The  pitch  of  the  note  produced  by  membranous  tongues  may  be 
affected  in  several  ways.  Thus,  an  increase  in  the  strength  of  the  blast,  which 
has  little  influence  on  metallic  reeds,  raises  their  pitch  very  considerably ;  and 


Artificial  Glottis. 


932  OP   THE   VOICE   AND    SPEECH. 

in  this  manner  the  note  of  a  membranous  reed  may  be  raised  by  semitones,  to 
as  much  as  a  fifth  above  the  fundamental.  The  addition  of  a  pipe  has  nearly 
the  same  effect  on  their  pitch  as  on  that  of  metallic  reeds ;  but  it  cannot  easily 
be  determined  with  the  same  precision.  The  effect  of  the  junction  of  a  pipe 
with  a  double  membranous  tongue  is  well  shown  in  the  Trumpet,  Horn,  and 
other  instruments,  which  require  the  vibration  of  the  lips,  as  well  as  a  blast 
of  air,  for  the  production  of  their  sound,  having  no  reed  of  their  own.  By 
some,  these  instruments  have  been  classed  with  Flute-pipes;  but  the  conditions 
of  their  action  are  entirely  different.  The  mouth-piece  of  the  horn  or  trumpet 
is  incapable  of  yielding  any  tone,  when  a  current  of  air  is  merely  blown  through 
it ;  and  the  lips  are  necessary  to  convert  it  into  a  musical  reed,  being  rendered 
tense  by  the  contraction  of  their  sphincter,  partly  antagonized  by  the  slightly 
dilating  action  of  other  muscles.  The  variation  of  the  tension  of  the  lips  is 
effected  by  muscular  effort ;  and  several  different  notes  may  be  produced  with  a 
pipe  of  the  same  length;  but  there  is  a  certain  length  of  the  column  of  air 
which  is  the  one  best  adapted  for  each  tone;  and  different  instruments  possess 
various  contrivances  for  changing  this.  It  has  been  recently  ascertained  that 
the  length  of  the  pipe  prefixed  to  the  reed  has  also  a  considerable  influence  on 
its  tone,  rendering  it  deeper  in  proportion  as  it  is  prolonged,  down  to  nearly  the 
octave  of  the  fundamental  note;  but  the  pitch  then  suddenly  rises  again,  as  in 
the  case  of  the  tube  placed  beyond  the  reed.  The  researches  of  Miiller,  how- 
ever, have  not  succeeded  in  establishing  any  very  definite  relation  between  the 
lengths  of  the  two  tubes,  in  regard  to  their  influence  on  the  pitch  of  the  reed 
placed  between  them. 

934.  From  the  foregoing  statements,  it  appears  that  the  true  theory  of  the 
Voice  may  now  be  considered  as  well  established,  in  regard  to  this  essential 
particular — that  the  sound  is  the  result  of  the  vibrations  of  the  vocal  ligaments, 
which  take  place  according  to  the  same  laws  with  those  of  metallic  or  other 
elastic  tongues :  and  that  the  pitch  of  the  notes  is  chiefly  governed  by  the  ten- 
sion of  these  laminae.1  With  respect,  however,  to  the  mode  and  degree  in 
which  these  tones  are  modified  by  the  shape  of  the  air-passages,  both  above  and 
below  the  larynx,  by  the  force  of  the  blast,  and  by  other  concurrent  circum- 
stances, little  is  certainly  known;  but  no  doubt  can  be  felt  that  these  modifica- 
tions are  of  great  importance,  when  we  observe  the  great  amount  of  muscular 
action  which  takes  place  consentaneously  with  the  production  of  vocal  tones, 
and  which  seems  designed  to  modify  the  length  and  tension  of  the  various  parts 
of  the  Vocal  Tube,  so  that  they  may  vibrate  synchronously  with  the  Vocal  Cords. 
Thus,  during  the  ascent  of  the  voice  from  the  deeper  to  the  higher  notes  of  the 
scale,  we  find  the  whole  larynx  undergoing  an  elevation  towards  the  base  of  the 
cranium,  the  thyroid  cartilage  being  drawn  up  within  the  os  hyoides,  so  as  even 
to  press  on  the  epiglottis;  at  the  same  time,  the  small  space  between  the  thyroid 
and  cricoid  cartilages,  or  crico-thyroid  chink,  is  closed  by  the  depression  of  the 
front  of  the  former  upon  the  latter  (§  928);  the  velum  palati  is  depressed  and 
curved  forwards;  and  the  tonsils  approach  one  another.  The  reverse  of  all 

1  It  is  considered,  however,  by  Mr.  Bishop  ("Cyclop,  of  Anat.  and  Physiol.,"  vol.  iv. 
p.  1486),  that  the  vocal  apparatus  combines  the  properties  of  a  stretched  cord,  a  mem- 
branous pipe  with  a  column  of  air  vibrating  in  it,  and  a  reed ;  and  is  the  perfect  type,  of 
which  these  instruments  are  only  imperfect  adaptations.  The  Author  is  unable,  how- 
ever, to  deduce  from  Mr.  Bishop's  previous  statements  the  grounds  upon  which  he  makes 
this  assertion;  and  does  not  understand  how  any  instrument  can  combine  the  actions  of 
strings  and  of  tongues,  the  laws  of  whose  vibration  are  so  different.  That  the  column  of 
air  in  the  air-passages  is  thrown  into  vibration  consentaneously  with  the  production  of 
sound  by  the  vocal  cords,  and  intensifies  that  sound  by  reciprocation,  can  scarcely  be 
doubted;  but  the  reasons  previously  given  appear  to  the  Author  sufficient  to  disprove  the 
notion,  that  this  vibration  is  at  all  more  essential  to  the  production  of  the  vocal  tone  than 
it  is  in  the  reed-pipe  of  an  organ. 


OF   THE   LARYNX,,    AND   ITS    ACTIONS.  933 

these  movements  takes  place  during  the  descent  of  the  voice. — A  very  import- 
ant adjunct  to  the  production  of  the  higher  notes  has  been  pointed  out  by 
Miiller,  as  being  afforded  by  the  modification  in  the  space  included  between  the 
two  sides  of  the  thyroid  cartilage,  which  is  effected  by  the  thyro-arytenoidei. 
He  had  experimentally  ascertained  that  the  introduction  of  a  hollow  plug  into 
the  upper  end  of  the  pipe  beneath  his  artificial  larynx  (and  therefore  just  below 
the  reed),  by  diminishing  its  aperture,  produced  a  considerable  elevation  of  the 
tone.  The  action  may  be  imitated  in  the  human  larynx,  when  made  the  sub- 
ject of  experiment,  by  compressing  the  thyroid  cartilage  laterally ;  and  in  this 
manner,  the  natural  voice  could  be  made  to  extend  through  a  range  that  could 
otherwise  be  only  reached  by  a  falsetto. — The  influence  of  the  prefixed  and  super- 
added  tubes,  in  modifying  the  tones  produced  by  the  Human  larynx,  has  been  found 
by  Prof.  Miiller  not  to  be  at  all  comparable  to  that  which  they  exercised  over  the 
artificial  larynx ;  the  reason  of  which  difference  does  not  seem  very  apparent.  It 
appears,  however,  that  there  is  a  certain  length  of  the  prefixed  tube — as  there  is  a 
certain  distance  of  the  vibrating  laminae,  and  a  certain  length  or  form  of  the  tube 
above — which  is  most  favorable  to  the  production  of  each  note;  and  the  downward 
movement  of  the  whole  vocal  organ,  which  takes  place  when  we  are  sounding  deep 
notes,  and  its  rise  during  the  elevation  of  the  tones,  have  been  supposed  to  have 
the  purpose  of  making  this  adjustment  in  the  length  of  the  trachea ;  but  this 
requires  the  supposition  that  the  real  length  of  the  trachea  is  shortened  whilst  it 
appears  extended — for  which  there  seems  no  foundation.  It  is  considered  by 
Mr.  Wheatstone  that  the  column  of  air  in  the  trachea  may  divide  itself  into 
"  harmonic  lengths,"  and  may  produce  a  reciprocation  of  the  tone  given  by  the 
vocal  ligaments  (§  899)  ;  and  in  this  manner  he  considers  that  the  falsetto  notes 
are  to  be  explained.  It  may  be  added,  that  the  partial  closing  of  the  epiglottis 
seems  to  assist  in  the  production  of  deep  notes,  just  as  the  partial  covering  of 
the  top  of  a  short  pipe  fixed  to  a  reed  will  lower  its  tone;  and  that  something 
of  this  kind  takes  place  during  natural  vocalization,  would"  appear  from  the 
retraction  and  depression  of  the  tongue,  which  accompany  the  lowering  of  the 
front  of  the  head,  when  the  very  lowest  notes  are  being  sounded.  The  experi- 
ments of  Savart  have  shown,  that  a  cavity  which  only  responds  to  a  shrill  note, 
when  its  walls  are  firm  and  dry,  may  be  made  to  afford  a  great  variety  of  lower 
tones  when  its  walls  are  moistened  and  relaxed  in  various  degrees.  This  obser- 
vation may  probably  be  applied  also  to  the  trachea. 

935.  The  falsetto  is  a  peculiar  modification  of  the  voice,  differing  from  the 
"  chest  voice,"  not  merely  in  the  higher  pitch  of  its  notes,  but  also  in  their 
quality ;  its  tones  being  less  reedy,  and  more  like  the  "  harmonic  notes"  of 
stringed  and  wind  instruments.  In  some  individuals,  the  chest  voice  passes 
by  imperceptible  gradations  into  the  falsetto,  whilst  in  others  the  transition  is 
abrupt ;  and  some  persons  can  sound  the  same  notes  in  the  two  different  regis- 
ters, these  notes  forming  the  upper  part  of  the  scale  of  the  chest  voice,  and  the 
lower  part  of  the  falsetto.  Thus,  a  gentleman  of  the  author's  acquaintance  has 
a  bass  voice  of  a  harsh,  reedy  character,  ranging  from  the  D  below  the  bass 
cleff  to  the  D  above  it  (two  octaves)  ;  whilst  his  falsetto,  which  is  remarkable 
for  its  clearness  and  smoothness,  ranges  from  the  A  on  the  highest  line  of  the 
bass  cleff  to  the  E  in  the  highest  space  of  the  treble  cleff.  Thus,  there  are  five 
notes  common  to  the  two  registers,  and  the  entire  voice  ranges  through  more 
than  three  octaves ;  but  from  want  of  a  gradual  passage  from  one  to  the  other, 
this  gentleman  can  only  sing  bass  parts  with  his  chest  voice,  or  alto  parts  with 
his  falsetto,  the  tenor  scale  extending  above  the  range  of  one,  and  below  that  of 
the  other. — With  regard  to  the  theory  of  the  production  of  the  falsetto  voice, 
there  has  been  considerable  difference  of  opinion  amongst  Physiologists  ;  and  it 
cannot  be  regarded  as  fully  determined.  By  Magendie  and  Mayo  it  was  main- 
tained that  these  tones  are  produced  by  the  vibration  of  the  vocal  cords  along 


934  OP   THE   VOICE   AND    SPEECH. 

only  half  their  length,  the  rima  glottidis  being  partly  closed  ;  and  this  explana- 
tion is  consistent  with  the  fact  that  a  far  smaller  quantity  of  air  is  required  for 
sustaining  a  falsetto  note,  than  for  a  note  of  the  ordinary  register,  even  though 
they  should  be  of  the  same  pitch.  By  Miiller,  again,  ifr  is  asserted  that 
in  the  production  of  the  falsetto  notes  merely  the  thin  border  of  the  glottis 
vibrates,  so  that  the  fissure  remains  distinctly  visible  ;  whilst  in  the  production 
of  the  ordinary  vocal  tones,  the  whole  breadth  of  the  vocal  ligaments  is  thrown 
into  strong  vibrations  which  traverse  a  wider  space,  so  that  a  confused  motion  is 
seen  in  the  lips  of  the  glottis,  rendering  its  fissure  indefinite.  It  is  not  impos- 
sible that  both  these  doctrines  are  correct ;  and  that,  in  the  production  of  fal- 
setto notes  the  vocal  ligaments  are  in  contact  with  each  other  for  part  of  their 
length,  and  that  only  their  thin  edges  are  in  vibration  in  the  remainder.  It 
has  been  pointed  out  by  Mr.  Bishop  (loc.  cit.)  that  at  the  moment  of  transition 
from  the  u  chest  voice"  to  the  "  falsetto  voice,"  the  crico-thyroid  chink,  which 
was  closed  during  the  production  of  the  highest  note  of  the  former,  suddenly 
opens  on  the  production  of  the  lowest  note  of  the  latter ;  thus  indicating  that 
the  Vocal  Cords  are  relaxed  in  the  passage  from  the  one  to  the  other,  as  must 
be  the  case,  if,  for  the  production  of  the  same  note,  they  be  only  put  in  vibra- 
tion along  a  part  of  their  length  j  so  that  it  would  not  seem  improbable  that 
the  cause  of  those  differences  in  the  mode  of  transition  which  have  been  already 
noticed,  lies  in  the  difference  in  the  proportional  amount  of  the  vocal  cords 
which  is  thus  thrown  out  of  use  by  the  partial  approximation  of  the  two  lips  of 
the  rima  glottidis.  It  is  further  remarked  by  Mr:  Bishop,  that,  in  the  passage 
from  the  chest  to  the  falsetto  voice,  the  larynx  descends  from  its  previously 
elevated  position,  and  gradually  rises  again  with  the  ascending  scale  of  falsetto 
notes  ;  and  he  mentions  a  case  of  double  falsetto,  in  which  a  third  register  ex- 
isted, and  in  which  the  relaxation  of  the  Vocal  cords  and  the  descent  of  the 
larynx  were  observed  at  its  commencement,  as  at  the  commencement  of  the 
second  or  ordinary' falsetto  register. — An  entirely  different  theory  of  the  falsetto 
has  been  given,  however,  by  MM.  Petrequin  and  Diday  j1  who  consider  that  the  fal- 
setto notes  are  not  produced  by  the  vibration  of  the  vocal  cords,  but  are  really 
"  flute  notes/'  formed  by  the  vibrations  of  the  column  of  air  to  which  the  rima 
glottidis  then  serves  as  the  embouchure.  This  view  harmonizes  well  with  some 
of  the  phenomena  of  the  falsetto  voice  ;  but  it  is  open  to  the  objections  already 
stated  in  regard  to  the  flute  theory  generally.  It  may  be  added  that  some  have 
attempted  to  show  that  the  falsetto  depends  upon  a  peculiar  action  of  the  parts 
above  the  larynx  ;  but  for  this  doctrine  there  is  no  foundation  whatever. 

936.  The  various  muscular  actions,  which  are  employed  in  the  production  and 
regulation  of  the  voice,  are  called  forth  by  an  impulse  which  has  been  shown 
(§  751)  to  be  really  automatic  in  its  operation,  and  to  be  completely  under  the 
influence  of  guiding  sensations,  although  usually  originating  in  a  Volitional 
determination,  or  giving  expression  to  Emotions  or  simply  to  Ideas.  This, 
however,  has  been  proved  to  be  true  of  all  Volitional  movements ;  so  that  the 
production  of  vocal  tones  constitutes  no  real  exception.  It  may  be  safely 
affirmed,  that  the  simple  utterance  of  sounds  is  in  itself  an  Instinctive  action ; 
although  the  combination  of  these,  whether  into  music  or  articulate  language, 
is  a  matter  of  acquirement,  which  is  much  more  readily  made  by  some  indi- 
viduals than  by  others.  No  definite  tone  can  be  produced  by  a  Voluntary 
effort,  unless  that  tone  be  present  to  the  Consciousness  during  an  interval — 
however  momentary — either  as  immediately  produced  by  an  act  of  Sensation, 
recalled  by  an  act  of  Conception,  or  anticipated  by  an  effort  of  the  Imagination. 
When  thus  present,  the  Will  can  enable  the  muscles  to  assume  the  condition 
requisite  to  produce  it ;  but  under  no  other  circumstances  does  this  happen, 

1  "  Gazette  Medicale,"  1844. 


OP   ARTICULATE    SOUNDS.  935 

except  through  the  particular  mode  of  discipline  by  which  the  congenitally  deaf 
may  be  trained  to  speak.  Such  persons  are  debarred  from  learning  the  use  of 
Voice  in  the  ordinary  manner  ;  for  the  necessary  guidance  cannot  be  afforded, 
either  through  sensations  of  the  present  or  conceptions  of  the  past,  and  the 
imagination  is  entirely  destitute  of  power  to  suggest  that  which  has  been  in  no 
shape  experienced.  But  they  may  be  taught  to  acquire  an  imperfect  speech, 
by  causing  them  to  imitate  particular  muscular  movements,  which  they  may  be 
made  to  see ;  being  guided  in  the  imitation  of  those  movements,  in  the  first 
place  by  watching  their  own  performance  of  them  in  a  looking-glass,  and  after- 
wards by  attending  to  the  muscular  sensations  which  accompany  them.  Many 
instances,  indeed,  are  on  record,  in  which  persons  entirely  deaf  were  enabled  to 
carry  on  a  conversation  in  the  regular  way ;  judging  of  what  was  said  by  the 
movements  of  the  lips  and  tongue,  which  they  had  learned  to  connect  with 
particular  syllables ;  and  regulating  their  own  voices  in  reply,  by  their  volun- 
tary power,  guided  in  its  exercise  by  their  muscular  sensations.1 

[In  the  foregoing  account  of  the  Physiology  of  Voice,  the  Author  has  been  chiefly  guided 
by  the  excellent  paper  by  Mr.  Willis  in  the  "Transactions  of  the  Cambridge  Philosophical 
Society,"  vol.  iv. ;  and  by  the  elaborate  investigations  of  Miiller  and  his  coadjutors,  as 
detailed  in  the  Fourth  Book  of  his  Physiology.  Mr.  Bishop's  account  of  the  Physiology 
of  Voice,  in  the  Fourth  Volume  of  the  "Cyclopaedia  of  Anatomy  and  Physiology"  may 
also  be  advantageously  consulted.] 

2 . —  Of  Articulate  Sounds. 

937.  The  larynx,  as  now  described,  is  capable  of  producing  those  tones  of 
which  Voice  fundamentally  consists,  and  the  sequence  of  which  becomes  Music  : 
but  Speech  consists  in  the  modification  of  the  laryngeal  tones,  by  other  organs 
intervening  between  the  Glottis  and  the  Os  externum,  so  as  to  produce  those 
articulate  sounds  of  which  language  is  formed.     It  cannot  be  questioned  that 
Music  has  its  language  ;  and  that  it  is  susceptible  of  expressing  the  emotional 
states  of  the  mind,  among  those  at  least  who  have  been  accustomed  to  associate 
these  with  its  varied  modes,  to  even  a  higher  degree  than  articulate  speech. 
But  it  is  incapable  of  addressing  the  intellect,  by  conveying  definite  ideas  of 
objects,  properties,  actions,  &c.,  in  any  other  way  than  by  a  kind  of  imitation, 
which  may  be  compared  to  the  signs  used  in  hieroglyphic  writing.     These  ideas 
it  is  the  peculiar  province  of  articulate  language  to  convey ;  and  we  find  that 
the  vocal  organ  is  adapted  to  form  a  large  number  of  simple  sounds,  which  may 
be  readily  combined  into  groups,  forming  words.     The  number  of  combinations 
which  can  be  thus  produced  is  so  inexhaustible,  that  every  language  has  its 
own  peculiar  series  ]  no  difficulty  being  found  in  forming  new  ones  to  express 
new  ideas.     There  is  considerable  diversity  in  different  languages,  even  with 
regard  to  the  use  of  the  simplest  of  these  combinations  ;  some  of  them  are  more 
easy  of  formation  than  others,  and  these  accordingly  eater  into  the  composition 
of  all  languages ;  whilst  of  the  more  difficult  ones,  some  are  employed  in  one 
language,  some  in  another — no  one  language  possessing  them  all.     Without 
entering  into  any  detailed  account  of  the  mechanism  required  to  produce  each 
of  these  simple  sounds,  a  few  general  considerations  will  be  offered  in  regard  to 
the  classification  of  them ;  and  the  peculiar  defect  of  articulation,  termed  Stam- 
mering, will  be  briefly  treated  of. 

938.  Vocal  sounds  are  divided  into  Vowels  and  Consonants;   and  the  dis- 
tinctive characters  of  these  are  usually  considered  to  be,  that  the  Vowels  are 
produced  by  the  Voice  alone,  whilst  the  sound  of  the  Consonant  is  formed  by 
some  kind  of  interruption  to  the  voice,  so  that  they  cannot  be  properly  expressed 

1  See  Dr.  Johnstone  "On  Sensation,"  p.  128. 


936  OF   THE   VQICE  AND    SPEECH. 

unless  conjoined  with  a  vowel.  The  distinction  may  be  more  correctly  laid 
down,  however,  in  this  manner:  the  Vowel  sounds  are  continuous  tones,  modi- 
fied by  the  form  of  the  aperture  through  which  they  pass  out  j  whilst  in  sound- 
ing Consonants,  the  breath  suffers  a  more  or  less  complete  interruption,  in  its 
passage  through  parts  anterior  to  the  larynx.  Hence  the  really  simple  Vowel 
sounds  are  capable  of  prolongation  during  any  time  that  the  breath  can  sustain 
them ;  this  is  not  the  case,  however,  with  the  real  Diphthongal  sounds  (of 
which  it  will  presently  appear  that  the  English  i  is  one) ;  whilst  it  is  true  of 
some  Consonants.  It  seems  to  have  been  forgotten  by  many  of  those  who  have 
written  upon  this  subject,  that  the  laryngeal  voice  is  not  essential  to  the  forma- 
tion of  either  vowels  or  consonants ;  for  all  may  be  sounded  in  a  whisper.  It  is 
very  evident,  therefore,  that  the  larynx  is  not  primarily  concerned  in  their  pro- 
duction ;  and  this  has  been  fully  established  by  the  following  experiment :  A 
flexible  tube  was  introduced  by  M.  Deleau  through  his  nostril  into  the  pharynx, 
and  air  was  impelled  by  it  into  the  fauces ;  then,  closing  the  larynx,  he  threw 
the  fauces  into  the  different  positions  requisite  for  producing  articulate  sounds, 
when  the  air  impelled  through  the  tube  became  an  audible  whisper.  The  ex- 
periment was  repeated,  with  this  variation — that  laryngeal  sounds  were  allowed 
to  pass  into  the  fauces ;  and  each  articulated  letter  was  then  heard  double,  in  a 
proper  voice  and  in  a  whisper. 

939.  That  the  Vowels  are  produced  by  simple  modifications  in  the  form  of 
the  external  passages,  is  easily  proved,  both  by  observation  and  by  imitative 
experiment.  When  the  mouth  is  opened  wide,  the  tongue  depressed,  and  the 
velum  palati  elevated,  so  as  to  give  the  freest  possible  exit  to  the  voice,  the 
vowel  a  in  its  broadest  form  (as  in  ah)  is  sounded.1  On  the  other  hand,  if  the 
oral  aperture  be  contracted,  the  tongue  being  still  depressed,  the  sound  oo  (the 
Continental  u)  is  produced.  If  attention  be  paid  to  the  state  of  the  buccal  cavity 
during  the  pronunciation  of  the  different  vowel  sounds,  it  will  be  found  to  un- 
dergo a  great  variety  of  modifications,  arising  from  varieties  of  position  of  the 
tongue,  the  cheeks,  the  lips,  and  velum  palati.  The  position  of  the  tongue  is, 
indeed,  one  of  the  primary  conditions  of  the  variation  of  the  sound ;  for  it  may 
be  easily  ascertained  that,  by  peculiar  inflexions  of  this  organ,  a  great  diversity 
of  vowel  sounds  may  be  produced,  the  other  parts  remaining  the  same.  Still 
there  is  a  certain  position  of  all  the  parts,  which  is  most  favorable  to  the  forma- 
tion of  each  of  these  sounds;  but  this  could  not  be  expressed  without  a  length- 
ened description.  The  following  table,  slightly  altered  from  that  of  Kempelen, 
expresses  the  relative  dimensions  of  the  buccal  cavity  and  of  the  oral  orifice,  for 
some  of  the  principal  of  these ;  the  number  5  expressing  the  largest  size,  and  the 
others  in  like  proportion  : — 

Vowel.  Sound.  Size  of  oral  opening.  Size  of  buccal  cavity. 

a  as  in  ah  5  5 

a  as  in  name  4  2 

e  as  in  theme  3  1 

o  as  in  cold  2  4 

oo  as  in  cool  1  5 

These  are  the  sounds  of  the  five  vowels,  a,  e,  i,  o,  u,  in  most  Continental 
languages ;  and  it  cannot  but  be  admitted  that  the  arrangement  is  a  much  more 
natural  one  than  that  of  our  own  vowel  series.  The  English  a  has  three  distinct 
sounds  capable  of  prolongation  •* — the  true  broad  a  of  ah,  slightly  modified  in 

1  This  sound  of  the  vowel  a  is  scarcely  used  in  our  language,  though  very  common  in 
most  of  the  continental  tongues ;  the  nearest  approach  to  it  in  English  is  the  a  in  far  ;  but 
this  is  a  very  perceptible  modification,  tending  towards  au. 

2  The  short  vowel  sounds,  as  a  in  fat,  e  in  met,  o  in  pot,  &c.,  are  not  capable  of  pro- 
longation. 


OF  ARTICULATE    SOUNDS.  937 

far  ;  the  a  of  fate,  corresponding  to  the  e  of  French ;  and  the  a  of  fall,  which 
should  be  really  represented  by  au.  This  last  is  a  simple  sound,  though  com- 
monly reckoned  as  a  diphthong.  In  Kempelen's  scale,  the  oral  orifice  required 
to  produce  it  would  be  about  3,  and  the  size  of  the  buccal  cavity  4.1  On  the 
other  hand,  the  sound  of  the  English  i  cannot,  like  that  of  a  true  vowel,  be 
prolonged  ad  libitum;  it  is  in  fact  a  sort  of  diphthong,  resulting  from  the  transi- 
tion from  a  peculiar  indefinite  murmur  to  the  sound  of  e,  which  takes  its  place 
when  we  attempt  to  continue  it.  The  sound  oy  or  oi,  as  in  oil,  is  a  good  ex- 
ample of  the  true  diphthong ;  being  produced  by  the  transition  from  au  to  e. 
In  the  same  manner,  the  diphthong  ou,  which  is  the  same  with  ow  in  owl,  is 
produced  in  the  rapid  transition  from  the  broad  a  of  ah,  to  the  oo  of  cool. — 
Much  discussion  has  taken  place  as  to  the  true  character  of?/,  when  it  commences 
a  word,  as  in  yet,  yawl,  &c. ;  some  having  maintained  that  it  is  a  consonant  (for 
the  very  unsatisfactory  reason,  that  we  are  in  the  habit  of  employing  a  rather 
than  an,  when  we  desire  to  prefix  the  indefinite  article  to  such  words),  whilst 
others  regard  it  as  a  peculiar  vowel.  A  slight  attention  to  the  position  of  tite 
vocal  organs  during  its  pronunciation  makes  it  very  clear  that  its  sound  in  such 
words  really  corresponds  with  that  of  the  long  (English)  e  ;  the  pronunciation 
of  the  word  yawl  being  the  same  as  that  of  eaul,  when  the  first  sound  is  not 
prolonged,  but  rapidly  transformed  into  the  second.  The  sound  of  the  letter 
w,  moreover,  is  really  of  the  vowel  character,  being  formed  in  the  rapid  tran- 
sition from  oo  to  the  succeeding  vowel ;  thus  wall  might  be  spelt  ooall.  Many 
similar  difficulties  might  be  removed,  and  the  conformity  between  spoken  and 
written  language  might  be  greatly  increased  (so  as  to  render  far  more  easy  the 
acquirement  of  the  former  from  the  latter),  by  due  attention  to  the  state  of  the 
vocal  organs  in  the  production  of  the  simple  sounds. 

940.  It  is  not  very  difficult  to  produce  a  tolerably  good  artificial  imitation 
of  the  Vowel  sounds.     This  was  accomplished  by  Kempelen,  by  means  of  an 
India-rubber  ball,  with  an  orifice  at  each  end,  of  which  the  lower  one  was  at- 
tached to  a  reed  :  by  modifying  the  form  of  the  ball,  the  different  vowels  could 
be  sounded  during  the  action   of  the  reed.     He  also  employed  a  short  funnel- 
like  tube,  and  obtained  the  different  sounds  by  covering  its  wide  opening  to  a 
greater  or  less  extent.     This  last  experiment  has  been  repeated  by  Mr.  Willis ; 
who  has  also  found  that  the  vowel  sounds  might  be  imitated  by  drawing  out  a  long 
straight  tube  from  the  reed.     In  this  experiment  he  arrived  at  a  curious  result: 
with  a  tube  of  a  certain  length,  the  series  of  vowels,  i,  e,  a,  o,  u,  was  obtained, 
by  gradually  drawing  it  out ;  but,  if  the  length  was  increased  to  a  certain  point, 
a  further  gradual  increase  would  produce  the   same  sequence  in  an  inverted 
order,  u,  o,  a,  e,  i  ;  a  still  further  increase  would  produce  a  return  to  the  first 
scale,  and  so  on.     When  the  pitch  of  the  reed  was  high,  and  the  pipe  short,  it 
was  found  that  the  vowels  o  and  u  could  not  be  distinctly  formed — the  proper 
tone  being  injured  by  the  elongation  of  the  pipe  necessary  to  produce  them  ;  and 
this,  Mr.  Willis  remarks,  is  exactly  the  case  in  the  Human  voice,  most  singers 
being  unable  to  pronounce  u  and  o  upon  their  highest  notes. 

941.  The  most  natural  primary  division  of  the  Consonants  is  into  those  which 
require  a  total  stoppage  of  the  breath  at  the  moment  previous  to  their  being 
pronounced,  and  which,  therefore,  cannot  be  prolonged ;  and  those  in  pronounc- 
ing which  the  interruption  is  partial,  and  which  can,  like  the  vowel  sounds,  be 

1  The  mode  of  making  a  determination  of  this  kind  may  here  be  given,  for  the  sake  of 
example.  If  the  broad  a  be  sounded,  the  mouth  and  fauces  being  opened  wide,  and  we 
contract  the  oral  orifice  by  degrees,  at  the  same  time  slightly  elevating  the  point  of  the 
tongue,  we  gradually  come  to  the  sound  of  au;  by  still  further  contracting  the  orifice,  and 
again  depressing  the  tongue,  we  form  oo.  On  the  other  hand,  in  sounding  e,  the  tongue  is 
raised  nearly  to  the  roof  of  the  mouth  ;  if  it  be  depressed,  without  the  position  of  the  lip<s 
being  altered,  au  is  given. 


938  OP   THE   VOICE  AND   SPEECH. 

prolonged  ad  libitum.  The  former  have  received  the  designation  of  explosive  ; 
and  the  latter  of  continuous. — In  pronouncing  the  explosive  consonants,  the  pos- 
terior nares  are  completely  closed,  so  that  the  exit  of  air  through  the  nose  is 
altogether  prevented ;  and  the  current  may  be  checked  in  the  mouth  in  three 
ways,  by  the  approximation  of  the  lips — by  the  approximation  of  the  point  of 
the  tongue  to  the  front  of  the  palate — and  by  the  approximation  of  the  middle 
of  the  tongue  to  the  arch  of  the  palate.  In  the  first  of  these  modes,  we  pro- 
nounce the  letters  5,  and  p  ;  in  the  second,  d,  and  t;  in  the  third,  the  hard  g, 
and  k.  The  difference  between  6,  d,  and  g,  on  the  one  hand,  and  p,  t,  and  &,1 
on  the  other,  seems  to  depend  on  this — that  in  the  former  group  the  approximating 
surfaces  are  larger,  and  the  breath  is  sent  through  them  more  strongly  at  the 
moment  of  opening  than  in  the  latter. — The  continuous  consonants  may  be 
again  subdivided,  according  to  the  degree  of  freedom  with  which  the  air  is  al- 
lowed to  make  its  exit,  and  the  compression  which  it  consequently  experiences. 
I.  The  first  class  includes  those,  in  which  no  passage  of  air  takes  place  through 
the  nose,  and  in  which  the  parts  of  the  mouth  that  produce  the  sound  are  nearly 
approximated  together,  so  that  the  compression  is  considerable.  This  is  the 
case  with  v,  and  /,  which  are  produced  by  approximating  the  upper  incisors  to 
the  lower  lip ;  and  which  stand  in  nearly  the  same  relation  to  each  other,  as 
that  which  exists  between  d  and  t,  or  b  and  p.  The  sibilant  sounds,  z  and  s, 
also  stand  in  a  similar  relation  to  each  other ;  they  are  produced  by  the  passage 
of  air  between  the  point  of  the  tongue  and  the  front  of  the  palate,  the  teeth  being 
at  the  same  time  nearly  closed.  The  simple  sound  sh  is  formed  by  narrowing 
the  channel  between  the  dorsum  of  the  tongue  and  the  palate  ;  the  former  being 
elevated  towards  the  latter,  through  a  considerable  part  of  its  length.  If,  in 
sounding  s,  we  raise  the  point  of  the  tongue  a  very  little,  so  as  to  touch  the 
palate,  the  sound  of  t  is  evolved ;  and  in  the  same  manner  d  is  produced  from 
z.  This  class  also  includes  tfie  th  ;  which,  being  a  perfectly  simple  sound,  ought 
to  be  expressed  by  a  single  letter,  as  in  Greek,  instead  of  by  two,  whose  com- 
bination does  not  really  produce  anything  like  it.  For  producing  this  sound, 
the  point  of  the  tongue  is  applied  to  the  back  of  the  incisors,  or  to  the  front  of 
the  palate,  as  in  sounding  t  f  but,  whilst  there  is  complete  contact  of  the  tip, 
the  air  is  allowed  to  pass  out  around  it.  n.  In  the  second  class  of  continuous 
consonants,  including  the  letters  m,  ?i,  ?,  and  r}  the  nostrils  are  not  closed;  and 
the  air  thus  undergoes  very  little  compression,  even  though  the  passage  of  air 
through  the  oral  cavity  is  almost  or  completely  checked.  In  pronouncing  m 
and  n,  the  breath  passes  through  the  nose  alone  :  and  the  difference  of  the  sound 
of  these  two  letters  must  be  due  to  the  variation  in  the  form  of  the  cavity  of  the 
mouth,  which  acts  by  resonance.  The  letter  m  is  a  labial,  like  b  ;  and  the  only 
difference  between  the  two  is,  that  in  the  former  the  nasal  passage  is  open,  whilst 
the  mouth  remains  closed;  whilst  in  the  latter,  the  nose  is  entirely  closed,  and  the 
sound  is  formed  at  the  moment  of  opening  the  mouth.  The  same  correspondence 
exists  between  n  and  t,  or  n  and  g  (the  particular  part  of  the  tongue  approximated 
to  the  palate  not  being  of  much  consequence  in  the  pronunciation  of  n);  and  hence 
it  is  that  the  transition  from  n  to  £,  or  from  n  to  g,  is  so  easy,  that  the  combina- 
tions nt  and  ng  are  found  abundantly  in  most  languages.  The  sound  of  I  is  pro- 
duced by  bringing  the  tip  of  the  tongue  into  contact  with  the  palate,  and  allowing 
the  air  to  escape  around  it,  at  the  same  time  that  a  vocal  tone  is  generated  in  the 
larynx ;  it  differs,  therefore,  from  th  in  the  position  at  whiclvthe  obstruction  is  inter- 
posed, as  well  as  in  the  slight  degree  of  compression  of  the  air  which  it  involves. 
The  sound  of  the  letter  r  depends  on  an  absolute  vibration  of  the  point  of  the  tongue 

1  For  the  sake  of  proper  comparison,  this  letter  should  be  sounded  not  as  kay,  but  as  key. 

2  Hence  it  is  easy  to  understand  the  substitution  of  t  or  d,  for  the  English  th,  by 
foreigners. 


OF   ARTICULATE    SOUNDS.  939 

in  a  narrow  current  of  air  forced  between  the  tongue  itself  and  the  palate.  HI. 
The  sounds  of  the  third  class  are  scarcely  to  be  termed  consonants,  since  they 
are  merely  aspirations  caused  by  an  increased  force  of  breath.  These  are  A, 
and  the  guttural  chl  of  most  foreign  languages  (the  Greek  *).  The  first  is  a 
simple  aspiration ;  the  second  an  aspiration  modified  by  the  elevation  of  the 
tongue,  causing  a  slight  obstruction  to  the  passage  of  air,  and  an  increased 
resonance  in  the  back  of  the  mouth.  This  sound  would  become  either  g  or  k, 
if  the  tongue,  whilst  it  is  being  produced,  were  carried  up  to  touch  the  palate.3 

942.  These  distinctions  come  to  be   of  much  importance,  when  we   apply 
ourselves  to  the  treatment  of  defects  of  articulation.     Great  as  is  the  number 
of  muscles  employed  in  the  production  of  definite  vocal  sounds,  the  number  is 
much  greater  for  those  of  articulate  language ;  and  the  varieties  of  combination 
which  we  are  continually  forming  unconsciously  to  ourselves,  would  not  be  sus- 
pected, without  a  minute  analysis  of  the  separate  actions.     Thus,  in  uttering 
the  explosive  sounds,  we  check  the  passage  of  air  through  the  posterior  nares, 
in  the  very  act  of  articulating  the  letter;  and  yet  this  important  movement 
commonly  passes  unobserved. — We  must  regard  the  power  of  forming  the  seve- 
ral articulate  sounds  which  have  been  adverted  to,  and  their  simple  combina- 
tions, as  so  far  resulting  from  intuition,  that  it  can  in  general  be  more  readily 
acquired  by  early  practice  than  other  actions  of  the  same  complexity ;  but  we 
find  that  among  different  Races  of  Men,  there  exist  tendencies  to  the  production 
of  different  sounds,  which,  though  doubtless  influenced  in  great  degree  by  early- 
habit  (since  we   find  that  children,  when  first  learning  to  speak,  form  their 
habits  of  vocalization  in  great  degree  in  accordance  with  the  examples  amidst 
which  thev  are  placed),  are  certainly  also  dependent  in  part  upon  congenital  con- 
stitution, as  we  often  see  in  the  case  of  children  among  ourselves,  who  grow  up 
with  certain  peculiarities  of  pronunciation  of  which  they  do  not  seem  able  to 
divest  themselves.     It  is,  however,  in  the  want  of  power  to  combine  the  dif- 
ferent muscular  actions  concerned  in  vocalization,  that  the  defect  termed  Stam- 
mering essentially  consists. 

943.  Many  theories  regarding  the  nature  of  Stammering  have  been  proposed; 
and  there  can  be  little  doubt  that  the  impediment  may  be  attributed  to  a  great 
variety  of  exciting  causes.     A  disordered  action  of  the  nervous  centres  must, 
however,  be  regarded  as  the  proximate  cause;  though  this  may  be  (to  use  the 
language  of  Dr.  M.  Hall)  either  of  centric  or  of  excentric  origin — that  is,  it  may 
result  from  a  morbid  condition  of  the  ganglionic  centre,  or  from  an  abnormal 
impression  conveyed  through  its  afferent  nerves.     When  of  centric  origin  (and 
this  is  probably  the  most  general  case),  the  phenomena  of  Stammering  and 
Chorea  have  a  close  analogy  to  each  other;  in  fact  stammering  is  frequently 
one  of  the  modes  in  which  the  disordered  condition  of  the  nervous  system  in 
Chorea  manifests  itself. — It  is  in  the  pronunciation  of  the  Consonants  of  the 
explosive  class,  that  the  stammerer  experiences  the  greatest  difficulty.     The 
total  interruption  to  the  breath  which  they  occasion  frequently  becomes  quite 
spasmodic;  and  the  whole  frame  is  thrown  into  the   most  distressing  semi-con- 
vulsive movement,  until  relieved  by  expiration.3     In  the  pronunciation  of  the 
continuous  Consonants  of  the  first  class,  the  stammerer  usually  prolongs  them, 
by  a  spasmodic  continuance  of  the  same  action;  and  there  is,  in  consequence, 
an  impeded,  but  not  a  suspended  respiration.     The  same  is  the  case  with  the  I 
and  r  in  the  second  class.     In  pronouncing  the  m  and  n,  on  the  other  hand,  as 
well  as  the  aspirates  and  vowels,  it  is  sometimes  observed  that  the  stammerer 

1  The  English  ch  is  merely  a  combination  of  t  with  sh  ;  thus  chime  might  be  spelt  tshime. 

2  The  general  classification  proposed  by  Dr.  M.  Hall  has  been  here  adopted,  with  some 
modification  as  to  the  details. 

8  By  Dr.  Arnott  this  interruption  is  represented  as  taking  place  in  the  larynx ;  that  such 
is  not  usually  the  case,  the  Author  believes  that  a  little  attention  to  the  ordinary  phenomena 
of  voice  will  satisfactorily  prove. 


940  OF  THE   VOICE   AND    SPEECH. 

prolongs  the  sound,  by  a  full  and  exhausting  expiration.  In  all  these  cases, 
then,  it  seeins  as  if  the  muscular  sense,  resulting  from  each  particular  combi- 
nation of  actions,  became  the  stimulus  to  the  involuntary  prolongation  of  that 
action.  It  is  possible  that  the  defect  may  result,  in  some  instances,  from  malfor- 
mation of  the  parts  about  the  fauces,  producing  an  abnormal  stimulus  of  this 
kind  in  some  particular  positions  of  the  organ;  and  such  cases  may  be  really 
benefited  by  an  operation  for  the  removal  of  these  parts.  But  the  effect  of  such 
an  operation  is  certainly  exerted  in  most  cases  through  the  mind  of  the  patient; 
the  expectation  of  benefit  from  it  tending  to  improve  his  command  over  the 
muscles  of  vocalization,  which  Emotional  excitement  always  impairs;  and  the 
improvement  is  usually  proportional  to  the  confidence  which  he  has  been  led  to 
feel  in  the  result.  The  slightest  disturbance  of  the  feelings  is  sufficient  in 
most  Stammerers  to  induce  a  complete  perturbation  of  the  vocal  powers ;  the 
very  fear  that  stammering  will  occur,  particularly  under  circumstances  which 
render  it  peculiarly  annoying,  is  often  sufficient  to  bring  it  on  in  a  predisposed 
subject;  and  the  tendency  to  consensual  imitation  sometimes  occasions  stam- 
mering in  individuals  (especially  children)  who  never  show  the  slightest  tend- 
ency to  it  except  when  they  witness  the  difficulty  in  others. 

944.  The  method  proposed  by  Dr.  Arnott  for  the  prevention  of  Stammering, 
consists  in  the  connection  of  all  the  words  by  a  vocal  intonation,  in  such  a 
waanner,  that  there  shall  never  be  an  entire  stoppage  of  the  breath.  It  is  justly 
remarked  by  Miiller,  however,  that  this  plan  may  afford  some  benefit,  but  can- 
not do  everything ;  since  the  main  impediment  occurs  in  the  middle  of  words 
themselves.  One  important  remedial  means,  on  which  too  much  stress  cannot 
be  laid,  is  to  study  carefully  the  mechanism  of  the  articulation  of  the  difficult 
letters,  and  to  practise  their  pronunciation  repeatedly,  slowly,  and  analytically. 
The  patient  would  at  first  do  well  to  practise  sentences  from  which  the  explosive 
consonants  are  omitted;  his  chief  difficulty,  arising  from  the  spasmodic  suspension 
of  the  expiratory  movement,  being  thus  avoided.  Having  mastered  these,  he  may 
pass  on  to  others,  in  which  the  difficult  letters  are  sparingly  introduced ;  and 
may  finally  accustom  himself  to  the  use  of  ordinary  language.  One  of  the  chief 
points  to  be  aimed  at  is  to  make  the  patient  feel  that  he  has  command  over  his 
muscles  of  articulation ;  and  this  is  the  best  done  }>y  gradually  leading  him 
from  that  which  he  finds  he  can  do,  to  that  which  he  fears  he  cannot.  The 
fact  that  stammering  people  are  able  to  sing  their  words  better  than  to  speak 
them,  has  been  usually  explained  on  the  supposition  that,  in  singing,  the  glottis  is 
kept  open,  so  that  there  is  less  liability  to  spasmodic  action;  if,  however,  as  here 
maintained,  the  spasmodic  action  is  not  in  the  larynx,  but  in  the  velum  palati 
and  the  muscles  of  articulation,  the  difference  must  be  due  to  the  direction  of 
the  attention  rather  to  the  muscles  of  the  larynx  than  to  those  of  the  mouth. 
One  of  the  most  important  objects  to  be  aimed  at  in  the  treatment  of  stam- 
mering, consists  in  the  prevention  of  all  Emotional  disturbance  in  connection 
with  the  act  of  Speech;  and  this  requires  the  exercise  of  the  Voluntary 
power  over  the  direction  of  the  thoughts,  in  the  following  mode's  :  1.  To 
reduce  mental  emotion,  by  a  daily,  hourly  habit  of  abstracting  the  mind  from 
the  subject  of  stammering,  both  while  speaking  and  at  other  times.  2.  To 
avoid  exciting  mental  emotion  by  attempting  unnecessarily  to  read  or  speak 
when  the  individual  is  conscious  that  he  shall  not  be  able  to  perform  these  actions 
without  great  distress.  3.  To  elude  mental  emotion,  by  taking  advantage  of 
any  little  artifice  to  escape  from  stammering,  so  long  as  the  artifice  continues  to 
be  a  successful  one. — Much  may  frequently  be  done,  also,  by  constitutional 
treatment,  adapted  to  improve  the  general  condition  of  the  nervous  system.1 

1  See  on  the  subject  of  "Stammering  and  its  Treatment,"  a  useful  pamphlet  under  this 
title,  by  Bacc.  Med.  Oxon.,  1850;  and  Mr.  Bishop's  treatise  "On  Articulate  Sounds,  and 
on  the  Causes  and  Cure  of  Impediments  of  Speech." 


INFLUENCE   OF   THE   NERVOUS    SYSTEM,    ETC.  941 


CHAPTER   XVIII. 

INFLUENCE   OF    THE   NERVOUS    SYSTEM   ON    THE   ORGANIC 
FUNCTIONS. 

945.  OF  the  modes  in  which  the  Nervous  System  influences  the  Organic 
Functions,  a  great  part  have  been  already  considered :  for  it  has  been  shown  to 
be  concerned  in  providing  the  conditions,  either  immediate  or  remote,  under 
which  alone  these  functions  can  be  performed ;  so  that,  when  its  activity  ceases, 
they  cannot  be  much  longer  maintained.  But  the  influence  of  the  Nervous 
System  is  not  alone  exerted  upon  the  motor  or  contractile  tissues  of  the  body; 
for  there  is  good  evidence  that  it  has  a  direct  operation  upon  the  molecular 
changes  which  constitute  the  functions  of  Nutrition,  Secretion,  &c.  ;  and  it  is 
quite  conformable  to  the  general  views  formerly  expressed  (CHAP,  in.)  respect- 
ing the  relations  of  the  different  kinds  of  Vital  Force,  that  the  nerve-force,  which 
is  itself  generated  by  cell-development,  should  in  its  turn  be  able  to  modify  other 
processes  of  cell-development  (§  111).  And  this  view  may  be  admitted  to  its 
fullest  extent,  without  our  thereby  being  led  to  regard  the  processes  in  question 
as  dependent  upon  Nervous  agency — a  doctrine  for  which  there  seems  no  valid 
foundation,  since  they  go  on  with  the  greatest  rapidity  and  energy  in  the  Vege- 
table kingdom,  in  which  nothing  approaching  to  a  Nervous  System  exists ;  whilst 
in  the  Animal  kingdom  they  take  place  with  equal  vigor,  long  before  the  least 
vestige  of  it  appears.  We  shall  see  that  in  the  earliest  condition  of  foetal  life, 
the  germ  consists  but  of  a  congeries  of  cells,  which  have  all  originated  in  a.  single 
one  (§  993) ;  and  from  this  mass,  the  several  tissues  and  organs  are  successively 
generated  by  the  processes  of  histological  and  morphological  transformation — one 
set  of  cells  being  converted  into  muscular  tissue,  another  into  nervous  tissue, 
another  into  mucous  membrane,  and  so  on.  Now  since  this  is  the  case,  it  is 
evident  that  all  these  processes  of  development  must  take  place,  in  virtue  of  the 
inherent  properties  of  the  primitive  substance  itself;  since  no  nervous  influence 
can  be  supposed  to  operate  before  nerves  are  called  into  existence.  Throughout 
the  Animal  body,  it  may  be  observed  that  the  more  Vegetative  the  nature 
of  any  function,  the  less  is  it  connected  with  the  Nervous  System ;  and  all  the 
experiments  which  have  been  regarded  as  proving  that  the  Organic  functions 
are  dependent  upon  Nervous  influence,  are  really  explicable,  fully  as  well,  upon 
the  supposition  that  they  are  capable  of  being  affected  by  it,  either  in  the  way  of 
excitement  or  retardation.  (See  §  447.)  Moreover,  there  is  abundant  evidence 
that  Secretion  may  take  place  after  the  death  of  the  general  system,  through  the 
persistence  of  certain  molecular  changes  whose  essential  conditions  are  not 
immediately  altered;  thus,  Mr.  T.  Bell  mentions  that,  in  dissecting  the  poison- 
apparatus  of  a  Rattlesnake  which  had  been  dead  for  some  hours,  the  poison  con- 
tinued to  be  secreted  so  fast  as  to  require  being  occasionally  dried  off.  This  is 
precisely  what  might  have  been  anticipated,  from  the  independent  power  of  growth 
in  the  secreting  cells;  and  other  acts  of  Nutrition  are  recorded  to  have  occurred 
under  similar  circumstances.  In  such  a  case,  the  Animal  body  is  reduced  to 
the  condition  of  a  Plant;  since  the  influence  of  the  Nervous  system  must  then 
be  entirely  extinct.  Upon  those  who  maintain  that  Nervous  agency  is  a  condi- 
tion essential  to  those  molecular  actions  of  which  Nutrition  and  Secretion  consist, 


942  INFLUENCE   OF   THE   NERVOUS    SYSTEM 

it  is  incumbent,  therefore,  to  offer  some  more  unexceptionable  proof  of  their 
position  than  has  yet  been  given;  since  their  doctrine  is  opposed  by  so  many 
considerations  of  great  weight. 

946.  That  many  of  the  Organic  Functions,  however,  are  directly  influenced 
})j  the  Nervous  System,  is  a  matter  which  does  not  admit  of  dispute ;  and  this 
influence,  exerted  sometimes  in  exciting,  sometimes  in  checking,  and  sometimes 
in  otherwise  modifying  them,  may  well  be  compared  to  that  which  the  hand 
and  heel  of  the  rider  have  upon  his  horse,  or  which   the  engine-driver  exerts 
over  a  locomotive.     It  is  most  remarkably  manifested  in  the  result  of  severe 
injury  of  the  Nervous  centres,  such  as  concussion  of  the  Brain  or  of  the  Solar 
plexus  (§  321);  for  this  does  not  merely  bring  about  a  suspension  of  the  re- 
spiratory and  other  movements  which  minister  to  the  Organic  functions,  hence 
inducing  a  gradual  stagnation  of  the  latter ;  but  occasions  a  sudden  and  complete 
cessation  of  the  whole  train  of  action,  which  cannot  be  attributed  to  any  other 
cause  than  a  positive  depressing  influence  of  some  kind,  propagated  through-  the 
Nervous  System.     In  such  cases,  even  the  vitality  of  the  Blood  is  often  affected  ; 
the  usual  coagulation  not  taking  place  after  death,  so  long,  at  least,  as  the  blood 
remains  within    the  vessels.     A  similar   general  depression  may  result  from 
Mental  Emotion,  operating  through  the  same  channel ;  but  this  more  commonly 
has  rather  a  local  action,  or  operates  more  gradually  (§  797). 

947.  The  influence  of  the  Nervous  System  is  often  especially  exerted  in 
giving  temporary  excitement  to  a  Secreting  process  which  need  not  be  kept  in 
constant  activity,  or  of  which   circumstances  may  occasionally  require  an  in- 
crease.    This  is  the  case,  for  example,  in  regard  to  the  secretions  connected 
with  the  process  of  digestion — the  Saliva,  Gastric  fluid,  Bile,  Pancreatic  fluid, 
&c. ;  all  of  these  being  excited  by  the  contact  of  the  substances  on  which  they 
act,  with  the  surfaces  on  which  their  respective  ducts  open.     The  secretion  of 
Milk,  again,  in  a  nursing  female,  may  be  excited  by  irritation  of  the  nipple; 
and  the  determination  of  blood  to  the  Mammae  during  pregnancy  arises  from  an 
increased  action  in  the  part,  which  is  probably  excited  sympathetically  by  the 
changes  occurring  in  the  Uterus;  and   for  this  kind  of  communication,  the 
Sympathetic  System  seems  to  afford  the  readiest  channel,  since  the  organs  in 
question  are  for  the  most  part  supplied  by  it.     There  is  an  apparent  exception, 
however,  in  the  case  of  the  Salivary  and  Lachrymal  glands,  which  are  supplied 
by  the  5th  Pair :  but  this  nerve  contains  so  many  organic  filaments,  and  is  so 
intimately  connected  with  the  Sympathetic,  as  evidently  to  supply  (in  the  head) 
the  place  of  a  separate  ganglionic  system.     It  is  by  Nervous  influence,  that  the 
mucous  secretion  covering  the  membranes  is  caused  to  be  regularly  formed  for 
their  protection;  for  it  is  shown  by  pathological  facts,  that  when  this  influence 
is  interrupted,  and  the  secretion  is  no  longer  supplied,  the  membrane,  losing 
its  protection,  is  irritated  by  the  air  or  the  fluids  with  which  it  may  be  in  con- 
tact, and  passes  into  an  inflammatory  condition.     This  is  partly  the  explanation 
of  the  fact,  which  has  been  well  ascertained,  that  the  eye  is  liable  to  suppurate 
when  the   5th   pair  has  been  divided;  and  that  the  mucous  membrane  of  the 
bladder  becomes  diseased  in  paraplegia. 

948.  The  influence  of  particular  conditions  of  the  Mind,  in  exciting  various 
Secretions,  is  a  matter  of  daily  experience.     The  flow  of  Saliva,  for  example, 
is  stimulated  by  the  idea  of  food,  especially  that  of  a  savory  character.     Lach- 
rymal secretion,  again,  which  is  continually  being  formed  to  a  small  extent  for 
the  purpose  of  bathing  the  surface  of  the  eye,  is  poured  out  in  great  abundance 
under  the  moderate  excitement  of  the  emotions,  either  of  joy,  tenderness,  or 
grief.     It  is  checked,  however,  by  violent  emotions;  hence  in  intense  grief,  the 
tears  do  not  flow ;  and  it  is  a  well-known  proof  of  moderated  sorrow  when  the 
gush  takes  place,  this  very  act  affording  a  further  relief  (§  797).     Violent  emo- 
tion may  also  suspend  the   Salivary  secretion  ;  as  is  shown  by  the  well-known 


ON   THE    ORGANIC   FUNCTIONS.  943 

test,  often  resorted  to  in  India,  for  the  discovery  of  a  thief  amongst  the  serv- 
ants of  a  family — that  of  compelling  all  the  parties  to  hold  a  certain  quantity 
of  rice  in  the  mouth  during  a  few  minutes— the  offender  being  generally  dis- 
tinguished by  the  comparative  dryness  of  his  mouthful  at  the  end  of  the  experi- 
ment. The  influence  of  the  emotion  of  love  of  offspring  in  increasing  the  secre- 
tion of  Milk  is  well  known.  The  formation  of  this  fluid  is  continually  going 
on  during  the  period  of  lactation  ;  but  it  is  greatly  increased  by  the  sight  of  the 
infant,  or  even  by  the  thought  of  him,  especially  when  associated  with  the  idea 
of  suckling;  this  gives  rise  to  the  sudden  rush  of  blood  to  the  gland,  which  is 
known  by  nurses  as  the  draught,  and  which  occasions  a  greatly  increased  secre- 
tion. The  strong  desire  to  furnish  milk,  together  with  the  irritation  of  the 
gland  through  the  nipple,  has  often  been  effectual  in  producing  the  secretion 
in  girls  and  old  women,  and  even  in  men.  The  quantity  of  the  Gastric  secre- 
tion is  increased  by  exhilaration,  at  least  if  we  may  judge  from  the  increase 
of  the  digestive  powers  under  such  circumstances.  Freedom  from  mental  anx- 
iety favors  the  secretion  of  Fat ;  whilst  continual  solicitude  effectually  checks 
the  disposition.  It  has  been  stated  that  total  despair  has  an  equal  tendency, 
with  absence  of  care,  to  produce  this  effect ;  persons  left  long  to  pine  in  con- 
demned cells,  without  a  shadow  of  hope,  frequently  becoming  remarkably  fat, 
in  spite  of  their  slender  fare.1  The  odoriferous  secretion  of  the  Skin,  which  is 
much  more  powerful  in  some  individuals  than  in  others,  is  increased  under  the 
influence  of  certain  mental  emotions  (as  fear  or  bashfulness),  and  commonly 
also  by  sexual  desire.  The  Sexual  secretions  themselves  are  strongly  influenced 
by  the  condition  of  the  mind.  When  it  is  frequently  and  strongly  directed 
towards  objects  of  passion,  these  secretions  are  increased  in  amount,  to  a  degree 
which  may  cause  them  to  be  a  very  injurious  drain  on  the  powers  of  the  sys- 
tem. On  the  other  hand,  the  active  employment  of  the  mental  powers  on  other 
objects  has  a  tendency  to  render  less  active,  or  even  to  check  altogether,  the 
processes  by  which  they  are  elaborated.3 

1  Fletcher's  "  Rudiments  of  Physiology,"  Partn.,  5,  p.  11. 

2  This  is  a  simple  physiological  fact,  but  of  high  moral  application.     The  Author  would 
say  to  those  of  his  younger  readers,  who  urge  the  wants  of  Nature  as  an  excuse  for  the 
illicit  gratification  of  the  sexual  passion,  "Try  the  effects  of  close  mental  application  to 
some  of  those  ennobling  pursuits,  to  which  your  profession  introduces  you,  in  combination 
with  vigorous  bodily  exercise  (for  the  effects  of  which  see  |  771),  before  you  assert  that 
the  appetite  is  unrestrainable,  and  act  upon  that  assertion."     Nothing  tends  so  much  to 
increase  the  desire,  as  the  continual  direction  of  the  mind  towards  the  object  of  its  gratifi- 
cation.    The  following  observations,  which  the  Author  believes  to  be  strictly  correct,  are 
extracted  from  a  valuable  little  work  (anonymous)  entitled  "  Be  not  deceived,"  addressed 
to  Young  Men ;  they  are  directed  to  those  who  maintain  that,  the  married  state  being 
natural  to  Man,  illicit  intercourse  is  necessary  for  those  who  are  prevented  by  circum- 
stances from  otherwise  gratifying  the  sexual  passion.     "When  the  appetite  is  naturally 
indulged,  that  is,  in  marriage,  the  necessary  energy  is  supplied  by  the  nervous  stimulus 
of  its  natural  accompaniment  of  love  before  referred  to,  which  prevents  the  injury  that 
would  otherwise  arise  from  the  increased  expenditure  of  animal  power :  and  in  like  man- 
ner also,  the  function  being  in  itself  grateful,  this  personal  attachment  performs  the  fur- 
ther necessary  office  of  preventing  immoderate  indulgence,  by  dividing  the  attention, 
through  the  numerous  other  sources  of  sympathy  and  enjoyment  which  it  simultaneously 
opens  to  the  mind.     But,  when  the  appetite  is  irregularly  indulged,  that  is  in  fornication, 
for  want  of  the  healthful  vigor  of  true  love,  its  energies  become  exhausted ;  and  from  the 
want  of  the  numerous  other  sympathetic  sources  of  enjoyment  in  true  love,  in  similar 
thoughts,    common  pursuits,    and    above   all  in    common   holy  hopes,    the   mere   gross 
animal    gratification   of  lust  is   resorted   to   with   unnatural  frequency,    and   thus   its 
powers  become  still  further  exhausted,  and,   therefore,  still  more  unsatisfying,  while, 
at  the  same  time,  a  habit  is  thus  created,  and  these  jointly  cause  an  increased  craving ; 
and  the  still  greater  deficiency  in  the  satisfaction  experienced  in  its  indulgence  further, 
continually,    ever  in    a    circle,  increases  —  the   habit,   demand,    indulgence,  consequent 
exhaustion,  diminished  satisfaction,   and  again  demand  —  till  the  mind  and  body  alike 
become  disorganized."     Such  considerations  as  these  may,  to  some  persons,  appear  mis- 


944  INFLUENCE   OF   THE   NERVOUS    SYSTEM 

949.  No  secretion  so   evidently  exhibits  the  influence    of  the  depressing 
Emotions,  as  that  of  the  Mammae;  but  this  may  be  partly  due  to  the  fact,  that 
the  digestive  system  of  the  Infant  is  a  more  delicate  apparatus  for  testing  the 
qualities  of  that  secretion,  than  any  which  the  Chemist  can  devise ;  affording 
proof,  by  disorder  of  its  function,  of  changes  in  the  character  of  the  Milk,  which 
no  examination  of  its  physical  properties  could  detect.     The  following  remarks 
on  this  subject  are  abridged  from  Sir  A.  Cooper's  valuable  work  on  the  Breast: 
"The  secretion  of  milk  proceeds  best  in  a  tranquil  state  of  mind,  and  with  a 
cheerful  temper;  then  the  milk  is  regularly  abundant,  and  agrees  well  with  the 
child.     On.the  contrary,  a,  fretful  temper  lessens  the  quantity  of  milk,  makes  it 
thin  and  serous,  and  causes  it  to  disturb  the  child's  bowels,  producing  intestinal 
fever  and  much  griping.     Fits  of  anger  produce  a  very  irritating  milk,  followed 
by  griping  in  the  infant,  with  green  stools.      Grief  has  a  great  influence  on 
lactation,  and  consequently  upon  the  child.     The  loss  of  a  near  and  dear  relation, 
or  a  change  of  fortune,  will  often  so  much  diminish  the  secretion  of  milk  as  to 
render  adventitious  aid  necessary  for  the  support  of  the  child.     Anxiety  of  mind 
diminishes  the  quantity,  and  alters  the  quality,  of  the  milk.     The  reception  of 
a  letter  which  leaves  the  mind  in  anxious  suspense  lessens  the   draught,  and 
the  breast  becomes  empty.     If  the  child  be  ill,  and  the  mother  is  anxious 
respecting  it,  she  complains  to  her  medical  attendant  that  she  has  little  milk, 
and  that  her  infant  is  griped,  and  has  frequent  green  and  frothy  motions.     Fear 
has  a  powerful  influence  on  the  secretion  of  milk.     I  am  informed  by  a  medical 
man  who  practises  much  among  the  poor,  that  the  apprehension  of  the  brutal 
conduct  of  a  drunken  husband  will  put   a  stop  for  a  time  to  the  secretion  of 
milk.     When  this  happens,  the  breast  feels  knotted  and  hard,  flaccid  from  the 
absence  of  milk,  and  that  which  is  secreted  is  highly  irritating,  and  some  time 
elapses  before  a  healthy  secretion  returns.      Terror ,  which  is  sudden  and  great 
fear,  instantly  stops  this  secretion."     Of  this,  two  striking  instances,  in  which 
the  secretion,  although  previously  abundant,  was  completely  arrested  by  this 
emotion,  are  detailed  by  Sir  A.  C.     "Those  passions  which  are  generally  sources 
of  pleasure,  and  which,  when  moderately  indulged,  are  conducive  to  health,  will, 
when  carried  to  excess,  alter,  and  even  entirely  check  the  secretion  of  milk." 

950.  There  is  even  evidence  that  the  Mammary  secretion  may  acquire  an 
actually  poisonous  character,  under  the  influence  of  violent  mental  excitement; 
for  certain  phenomena  which  might   otherwise  be   regarded  in  no  other  light 
than  as  simple  coincidences,  appear  to  justify  this  inference,  when  interpreted 
by  the  less  striking  but  equally  decisive  facts  already  mentioned.     "A  carpen- 
ter fell  into  a  quarrel  with  a  soldier  billeted  in  his  house,  and  was  set  upon  by 
the  latter  with  his  drawn  sword.     The  wife  of  the  carpenter  at  first  trembled 
from  fear  and  terror,  and  then  suddenly  threw  herself  furiously  between  the 
combatants,  wrested  the  sword  from  the  soldier's  hand,  broke  it  in  pieces,  and 
threw  it  away.     During  the  tumult,  some  neighbors  came  in  and  separated  the 
men.     While  in  this  state  of  strong  excitement,  the  mother  took  up  her  child 

placed  in  a  Physiological  Treatise — yet  the  Author  feels  sure  that,  by  his  well-judging 
readers,  he  will  not  be  blamed  for  adverting  to  this  subject,  or  for  the  introduction  of  the 
above  quotation  from  a  writer  of  whom  he  has  no  personal  knowledge,  but  whose 
object  must  be  confessed  by  all  to  be  laudable.  There  seems  to  be  something  in  the  pro- 
cess of  training  young  men  for  the  Medical  Profession,  which  encourages  in  them  a  laxity 
of  thought  and  expression  on  these  matters  that  generally  ends  in  a  laxity  of  principle 
and  of  action.  It  might  have  been  expected  that  those  who  are  so  continually  witnessing 
the  melancholy  consequences  of  the  violation  of  the  Divine  law  in  this  particular,  would 
be  the  last  to  break  it  themselves ;  but  this  is  unfortunately  very  far  from  being  the  case. 
The  Author  regrets  to  be  obliged  further  to  remark,  that  some  works  which  have  issued 
from  the  Medical  press  contain  much  that  is  calculated  to  excite,  rather  than  to  repress, 
the  propensity;  and  that  the  advice  sometimes  given  by  practitioners  to  their  patients  is 
immoral  as  well  as  unscientific. 


ON   THE   ORGANIC   FUNCTIONS.  945 

from  the  cradle,  where  it  lay  playing,  and  in  the  most  perfect  health,  never 
having  had  a  moment's  illness;  she  gave  it  the  breast,  and  in  so  doing  sealed 
its  fate.  In  a  few  minutes  the  infant  left  off  sucking,  became  restless,  panted, 
and  sank  dead  upon  its  mother's  bosom.  The  physician,  who  was  instantly 
called  in,  found  the  child  lying  in  the  cradle,  as  if  asleep,  and  with  its  features 
undisturbed ;  but  all  his  resources  were  fruitless.  It  was  irrecoverably  gone."1 
In  this  interesting  case,  the  milk  must  have  undergone  a  change,  which  gave  it 
a  powerful  sedative  action  upon  the  susceptible  nervous  system  of  the  infant. — 
The  following,  which  occurred  within  the  Author's  own  knowledge,  is  perhaps 
equally  valuable  to  the  Physiologist,  as  an  example  of  the  similarly  fatal  in- 
fluence of  undue  emotion  of  a  different  character ;  and  both  should  serve  as  a 
salutary  warning  to  mothers,  not  to  indulge  either  in  the  exciting  or  depressing 
pasvsions.  A  lady  having  several  children,  of  which  none  had  manifested  any 
particular  tendency  to  cerebral  disease,  and  of  which  the  youngest  was  a  healthy 
infant  a  few  months  old,  heard  of  the  death  (from  acute  hydrocephalus)  of  the 
infant  child  of  a  friend  residing  at  a  distance,  with  whom  she  had  been  on  terms 
of  close  intimacy,  and  whose  family  had  increased  almost  contemporaneously 
with  her  own.  The  circumstance  naturally  made  a  strong  impression  on  her 
mind ;  and  she  dwelt  upon  it  the  more,  perhaps,  as  she  happened,  at  that  period, 
to  be  separated  from  the  rest  of  her  family,  and  to  be  much  alone  with  her  babe. 
One  morning,  shortly  after  having  nursed  it,  she  laid  the  infant  in  its  cradle, 
asleep  and  apparently  in  perfect  health ;  her  attention  was  shortly  attracted  to 
it  by  a  noise  ;  and,  on  going  to  the  cradle,  she  found  her  infant  in  a  convulsion, 
which  lasted  a  few  moments  and  then  left  it  dead.  Now,  although  the  influence 
of  the  mental  emotion  is  less  unequivocally  displayed  in  this  case  than  in  the  last, 
it  can  scarcely  be  a  matter  of  doubt ;  since  it  is  natural  that  no  feeling  should 
be  stronger  in  the  mother's  mind,  under  such  circumstances,  than  the  fear  that 
her  own  beloved  child  should  be  taken  from  her,  as  that  of  her  friend  had  been ; 
and  it  is  probable  that  she  had  been  particularly  dwelling  on  it,  at  the  time  of 
nursing  the  infant  on  that  morning. — Another  instance,  in  which  the  maternal 
influence  was  less  certain,  but  in  which  it  was  not  improbably  the  immediate 
cause  of  the  fatal  termination,  occurred  in  a  family  nearly  related  to  the  Author's. 
The  mother  had  lost  several  children  in  early  infancy,  from  a  convulsive  disor- 
der ;  one  infant,  however,  survived  the  usually  fatal  period  ;  but  whilst  nursing 
him  one  morning,  she  had  been  strongly  dwelling  on  the  fear  of  losing  him  also, 
although  he  appeared  a  very  healthy  child.  In  a  few  minutes  after  the  infant 
had  been  transferred  into  the  arms  of  the  nurse,  and  whilst  she  was  urging  her 
mistress  to  take  a  more  cheerful  view,  directing  her  attention  to  his  thriving  ap- 
pearance, he  was  seized  with  a  convulsion-fit,  and  died  almost  instantly.  Now, 
although  there  was  here  unquestionably  a  predisposing  cause,  of  which  there  is 
evidence  in  the  other  cases,  it  can  scarcely  be  doubted  that  the  exciting  cause  of 
the  fatal  disorder  is  to  be  referred  to  the  mother's  anxiety.  This  case  offers  a 
valuable  suggestion — which,  indeed,  would  be  afforded  by  other  considerations — 
that  an  infant,  under  such  circumstances,  should  not  be  nursed  by  its  mother, 

'  Dr.  Von  Ammon,  in  his  treatise  "Die  ersten  Mutterpflichten  und  die  erste  Kindesp- 
flege,"  quoted  in  Dr.  A.  Combe's  excellent  little  work  on  "The  Management  of  In 
fancy." — Similar  facts  are  recorded  by  other  writers.  Mr.  Wardrop  mentions  ("  Lancet," 
No.  516),  that  having  removed  a  small  tumor  from  behind  the  ear  of  a  mother,  all  went 
well,  until  she  fell  into  a  violent  passion ;  and  the  child,  being  suckled  soon  afterwards, 
died  in  convulsions.  He  was  sent  for  hastily  to  see  another  child  in  convulsions,  after 
taking  the  breast  of  a  nurse  who  had  just  been  severely  reprimanded ;  and  he  was  in- 
formed by  Sir  Richard  Croft  that  he  had  seen  many  similar  instances.  Three  others  are 
recorded  by  Burdach  ("Physiologic,"  \  522) ;  in  one  of  them,  the  infant  was  seized  with 
convulsions  on  the  right  side,  and  hemiplegia  on  the  left,  on  sucking  immediately  after  its 
mother  had  met  with  some  distressing  occurrence.  Another  case  was  that  of  a  puppy, 
which  was  seized  with  epileptic  convulsions,  on  sucking  its  mother  after  a  fit  of  rage. 

60 


946  INFLUENCE   OF   THE    NERVOUS    SYSTEM 

but  by  another  woman  of  placid  temperament,  who  has  reared  healthy  children 
of  her  own. 

951.  Other  Secretions   are  in  like  manner  vitiated  by  mental  Emotions, 
although  the  influence  is  not  always  so  manifest.     Thus,  the  halitus  from  the 
lungs  is  sometimes  almost  instantaneously  affected  by  bad  news,  so  as  to  pro- 
duce fetid  breath.     A   copious  secretion  of  fetid  gas  not  unfrequently  takes 
place  in  the  intestinal  canal,  under  the  influence  of  any  disturbing  emotion ;  or 
the  usual  fluid  secretions  from  its  walls  are  similarly  disordered.     The  tendency 
to  Defecation  which  is  commonly  excited  under  such  circumstances  is  not,  there- 
fore, due  simply  to  the  relaxation  of  the  sphincter  ani  (as  commonly  supposed)  ; 
but  is  partly  dependent  on  the  unusually  stimulating  character  of  the  faeces 
themselves.     The  same  may  be  said  of  the  tendency  to  Micturition,  which  is 
experienced  under  similar  conditions  ;  the  change  in  the  character  of  the  urine 
becoming  perceptible  enough  among  many  animals,  in  which  it  acquires  a  pow- 
erfully disagreeable  odor  under  the  influence  of  fear,  and  thus  answers  the  pur- 
pose which  is  effected  in  others  by  a  peculiar  secretion.     It  is  a  prevalent,  and 
perhaps  not  an  ill-founded  opinion  that  melancholy  and  jealousy  have  a  tend- 
ency to  increase  the  quantity,  and  to  vitiate  the  quality  of  the  biliary  fluid  ; 
perhaps  the  disorder  of  the  organic  function  is  more  commonly  the  source  of  the 
former  emotion,  than  its  consequence  ;    but  it  is  certain  that  the  indulgence 
of  these  feelings  produces  a  decidedly  morbific  effect  by  disordering  the  diges- 
tive processes,  and  thus  reacts  upon  the  nervous  system  by  impairing  its  healthy 
nutrition. 

952.  The  influence  of  the  Nervous  System  upon  those  formative  processes 
which  constitute  the  function  of  Nutrition  is  less  evident  than  it  is  upon  the 
Secretory  operations  ;  and  the  nature  of  this  influence  is  rather  to  be  inferred 
from  the  results  of  its  withdrawal,  than  to  be  demonstrated  in  any  more  direct 
manner.     These  results  are  chiefly  to  be  seen  in  the  altered  nutrition  of  parts 
exposed  to  external  impressions,  as  the  integuments  generally,  but  particularly 
those  of  the  extremities ;   and  they  may  be  generally  expressed  by  the  state- 
ment, that  the  withdrawal  of  nervous  influence  from  a  part  renders  it  less  able 
to  withstand  the  destructive  influence  of  physical  agencies.     It  is  certain,  how- 
ever, that  a  great  part  of  the  injurious  effects  which  may  be  observed  to  follow 
injuries  of  the  nerves  of  the  extremities  experimentally  inflicted,  are  traceable 
to  want  of  power  on  the  part  of   the  animal,  consequent  upon  the  paralyzed 
state  of  the  limbs,  to  withdraw  them  from  irritating  impressions  (§  394,  note), 
and  must  not  be  attributed  to  any  direct  deterioration  of  the  formative  opera- 
tions, consequent  upon  the  withdrawal  of  nervous  agency.     The  following  case, 
however,  which  is  given  by  Mr.  Paget1  on  the  authority  of  Mr.   Hilton,  seems 
more  unequivocally  to  establish  this  connection  :  "  A  man  was  at  Guy's  Hospi- 
tal, several  years  ago,  who,  in  consequence  of  a  fracture  at  the  lower  end  of 
the  radius,  repaired  by  an  excessive  quantity  of  new  bone,  suffered  compression 
of  the  median  nerve.     He  had  ulceration  of  the  thumb,  and  of  the  fore  and 
middle  fingers,  which  had  resisted  various  treatment,  and  was  cured  only  by  so 
binding  the  wrist  that  the  parts  on  the  palmar  aspect  being  relaxed,  the  pressure 
on  the  nerve  was  removed.     So  long  as  this  was  done,  the  ulcers  became  and  re- 
mained well ;  but  as  soon  as  the  man  was  allowed  to  use  his  hand,  the  pressure 
on  the  nerves  was  removed,  and  the  ulceration  in  the  parts  supplied  by  it  re- 
turned."   Mr.  Paget  also  mentions  the  following  curious  case  :   u  A  lady,  who  is 
subject  to  attacks  of  what  are  called  nervous  headaches,  always  finds  next  morning 
that  some  patches  of  her  hair  are  white,  as  if  powdered  with  starch.  The  change  is 
effected  in  a  night;  and  in  a  few  days  after,  the  hairs  gradually  regain  their  dark 
brownish  color." — That  such  effects  are  rather  to  be  attributed  to  the  loss  or 

1  "  Lectures  on  Nutrition,"  &c.,  in  "Medical  Gazette,"  1847. 


ON    THE   ORGANIC   FUNCTIONS.  947 

perversion  of  the  influence  of  the  Sympathetic  System,  than  to  that  of  the 
Cerebro-spinal,  would  appear  from  the  fact  noticed  by  Magendie  and  Longet, 
that  destructive  inflammation  of  the  eye  ensues  more  quickly  after  division  of 
the  Trigeminal  nerve  in  front  of  the  Grasserian  ganglion,  than  when  the  division 
is  made  through  the  roots  of  the  nerve,  between  that  ganglion  and  the  brain ; 
the  sympathetic  filaments  which  exist  largely  in  this  nerve  being  interrupted  in 
their  course  to  the  tissues  in  the  former  case,  but  not  in  the  latter.  And  this 
inference  would  be  supported  by  the  fact  that  increased  secretion  of  tears  and 
mucus  from  the  eye,  and  increased  redness  of  the  conjunctiva,  are  ordinary  con- 
sequences of  extirpation  of  the  superior  cervical  ganglion  of  the  sympathetic  in 
dogs ;  and  also  with  the  general  result  of  observation,  that  atrophy  of  parts 
supplied  by  the  spinal  nerves  is  much  greater  when  the  sensory  as  well  as  the 
motor  roots  are  involved,  than  when  the  latter  alone  are  paralyzed — it  being 
through  the  ganglia,  and  connecting  filaments  of  the  former  that  the  true  Sym- 
pathetic fibres  become  incorporated  with  the  Cerebro-spinal  nerves. 

953.  The  influence  of  the  state  of  expectant  attention,  in  modifying  the  pro- 
cesses of  Nutrition  and  Secretion,  is  not  less  remarkable  than  we  have  already 
seen  it  to  be  in  the  production  or  modification  of  Muscular  movements  (§  923). 
It  seems  certain  that  the  simple  direction  of  the  consciousness  to  a  part,  inde- 
pendently of  emotional  excitement,  but  with  the  expectation  that  some  change 
will  take  place  in  its  organic  activity,  is  often  sufficient  to  induce  such  an  altera- 
tion ;  and  would  probably  always  do  so,  if  the  concentration  of  the  attention 
were  sufficient.  The  most  satisfactory  exemplification  of  this  principle  has 
been  given  by  the  experiments  of  Mr.  Braid,  who  has  succeeded  in  producing 
very  decided  changes  in  the  secretions  of  particular  organs,  by  the  fixation  of 
the  attention  upon  them  in  the  "  hypnotic"  state  (§  827).  Thus  he  brought 
back  an  abundant  flow  of  milk  to  the  breast  of  a  female  who  was  leaving  off 
nursing  from  defect  of  milk,  and  repeated  the  operation  upon  the  other  breast 
a  few  days  subsequently,  after  which  the  supply  was  abundant  for  nine  months; 
and  in  another  instance  he  induced  the  catamenial  flow  on  several  successive 
occasions,  when  the  usual  time  of  its  appearance  had  passed.  It  is  not  requi- 
site, however,  to  produce  the  state  of  Somnambulism  for  this  purpose,  if  the 
attention  can  be  sufficiently  drawn  to  the  subject  in  any  other  mode;  thus  Mr. 
Braid  has  repeatedly  produced  the  last-named  result  on  a  female  who  possessed 
considerable  power  of  mental  concentration,  by  inducing  her  to  fix  her  thoughts 
upon  it  for  ten  or  fifteen  minutes,  so  as  to  bring  on  a  state  of  reverie. — Now 
the  effects  which  are  producible  by  this  voluntary  direction  of  the  consciousness 
to  the  result,  are  doubtless  no  less  producible  by  that  involuntary  fixation  of 
the  attention  upon  it,  which  is  consequent  upon  the  eager  expectation  of  benefit 
from  some  curative  method  in  which  implicit  confidence  is  placed,  or,  on  the 
other  hand,  upon  that  anticipation  of  unpleasant  results  in  which  some  in- 
dividuals are  led  to  indulge  by  the  morbid  state  of  their  feelings.  It  is  to 
such  a  state  that  we  may  fairly  attribute  most,  if  not  all,  the  cures  which 
have  been  worked  by  what  is  popularly  termed  the  "imagination."  The 
cures  are  real  facts,  however  they  may  be  explained;  and  there  is  scarcely 
a  malady  in  which  amendment  has  not  been  produced  not  merely  in  the 
estimation  of  the  patient,  but  in  the  more  trustworthy  opinion  of  medical 
observers,  by  practices  which  can  have  had  no  other  effect  than  to  direct  the 
attention  of  the  sufferer  to  the  part,  and  to  keep  alive  his  confident  expectation 
of  the  cure.  The  "  charming-away"  of  warts  by  spells  of  the  most  vulgar  kind, 
the  imposition  of  royal  hands  for  the  cure  of  the  "evil,"  the  pawings  and  strok- 
ings  of  Valentine  Greatrakes,  the  manipulations  practised  with  the  "  metallic 
tractors,"  the  invocations  of  Prince  Hohenlohe,  et  hoc  genus  omne — not  omit- 
ting the  globulistic  administrations  of  the  Infinitesimal  doctors,  and  the  manipu- 
lations of  the  Mesmerists,  of  our  own  times — have  all  worked  to  the  same  end, 


948  OF   GENERATION. 

and  have  all  been  alike  successful.  It  is  unquestionable  that,  in  all  such  cases, 
the  benefit  derived  is  in  direct  proportion  to  the  faith  of  the  sufferer  in  the 
means  employed ;  and  thus  we  see  that  a  couple  of  bread  pills  will  produce 
copious  purgation,  and  a  dose  of  red  poppy  syrup  will  serve  as  a  powerful  narco- 
tic (as  has  happened  within  the  personal  knowledge  of  the  Author),  if  the 
patient  have  been  led  to  feel  a  sufficiently  confident  expectation  of  the  respective 
results  of  these  medicaments.1 — This  state  of  confident  expectation,  however, 
may  operate  for  evil,  no  less  than  for  good.  A  fixed  belief  that  a  mortal  dis- 
ease had  seized  upon  the  frame,  or  that  a  particular  operation  or  system  of  treat- 
ment would  prove  unsuccessful,  has  been  in  numerous  instances  (there  is  no 
reason  to  doubt)  the  direct  cause  of  a  fatal  result.  And  thus  the  morbid  feel- 
ings of  the  hypochondriac,  who  is  constantly  directing  his  attention  to  his  own 
fancied  ailments,  tend  to  induce  real  disorder  in  the  action  of  the  organs  which 
are  supposed  to  be  affected.  In  the  same  category,  too,  may  be  placed  those' 
instances  (to  which  alone  any  value  is  to  be  attached),  wherein  a  strong  and 
persistent  impression  upon  the  mind  of  a  mother  has  appeared  to  produce  a 
corresponding  effect  upon  the  development  of  the  foetus  in  utero.  In  this  case, 
the  effect  (if  admitted  to  be  really  exerted)  must  be  produced  upon  the  maternal 
blood,  and  transmitted  through  it  to  the  foetus ;  since  there  is  no  nervous  com- 
munication between  the  parent  and  offspring.  There  is  no  difficulty,  however, 
in  understanding  how  this  may  occur,  after  what  has  been  stated  on  a  former 
occasion  (§  203)  of  the  influence  of  minute  alterations  in  the  condition  of  the 
blood,  in  determining  local  alterations  of  nutrition. 


CHAPTER  XIX. 

OF   GENERATION. 

1. —  General  Character  of  the  Function. 

954.  HAVING  now  passed  in  review  the  various  operations  which  are  con- 
cerned in  maintaining  the  life  of  the  individual,  we  have  next  to  proceed  to 
those  which  are  destined  to  the  perpetuation  of  the  race,  by  the  production  of 
successive  generations  of  similar  beings.  In  Man  and  the  higher  animals,  this 
function  is  performed  in  only  one  method ;  namely,  by  the  development  of  an 
ovum  in  the  Female,  which,  when  fertilized  by  the  spermatozoon  of  the  Male, 
gives  origin  within  itself  to  a  new  being ;  the  embryo,  if  supplied  with  the  re- 
quisite nourishment,  warmth,  &c.,  gradually  evolving  itself  into  the  likeness  of 
its  parents.  This  process  appears,  as  will  presently  be  shown,  to  be  performed 
in  a  manner  essentially  the  same,  not  only  throughout  the  Animal  kingdom,  but 
through  the  Vegetable  kingdom  also.  But  among  Plants,  and  the  lower  tribes 
of  Animals,  we  find  an  additional  method  of  propagation;  for,  without  any 

i  It  is  commonly  said  that  these  effects  are  produced  by  the  imagination;  but  this  only 
serves  to  induce  the  belief  that  the  sham  remedy  is  one  of  real  efficacy  ;  and  it  is  the  state 
of  "expectant  attention"  which  is  the  immediate  operating  agent,  and  which  is  necessary 
to  the  result. — In  whatever  mode  this  can  be  induced,  the  effect  will  be  the  same.  Thus 
Dr.  Haygarth,  of  Bath  (in  conjunction  with  Mr.  Richard  Smith,  of  Bristol),  tested  the  value 
of  the  "metallic  tractors,"  by  substituting  two  pieces  of  wood  painted  in  imitation  of  them, 
or  even  a  pair  of  tenpenny  nails  disguised  with  sealing-wax,  or  a  couple  of  slate-pencils ; 
which  they  found  to  possess  all  the  virtues  that  were  claimed  for  the  real  instruments, 
because  the  state  of  "expectant  attention"  was  equally  induced  by  either. 


GENERAL   CHARACTER   OP   THE   FUNCTION.  949 

sexual  process  whatever,  new  beings  maybe  formed  by  gemmation  or  "budding" 
from  the  parent-stock,  and  these,  gradually  becoming  less  and  less  dependent 
upon  it,  at  last  detach  themselves  and  maintain  a  separate  existence.  Now  this 
process  may  be  regarded  as  essentially  the  same  with  that  of  the  multiplication 
of  cells  by  subdivision,  which  we  have  seen  to  be  the  most  common  mode  of 
propagation  in  the  simplest  cellular  Plants  (§  104) ;  and  it  differs  from  the  ordi- 
nary operations  of  growth  and  development  in  no  other  particular  than  this — 
that  the  newly-formed  structure,  instead  of  remaining  as  a  constituent  and 
dependent  part  of  the  parental  fabric,  is  capable  of  living  independently  of  it, 
and  of  thus  existing  as  a  distinct  individual  when  spontaneously  or  artificially 
detached.  Among  the  higher  tribes  of  animals,  as  in  Man,  this  mode  of  mul- 
tiplication of  individuals  does  not  present  itself,  at  least  in  the  adult  state ;  for 
in  no  instance  do  we  find  that  a  part  of  the  body  separated  from  the  rest  can 
develop  the  organs  which  are  necessary  for  the  sustenance  of  its  existence ;  and 
the  power  which  the  organism  possesses  of  regenerating  parts  which  it  has  lost  by 
disease  or  accident  is  restrained  within  very  narrow  limits  (§  599).  But  there 
is  good  ground  to  believe  that  such  a  multiplication  by  subdivision  may  take 
place  at  that  earliest  period  of  embryonic  life  at  which  the  germ  is  nothing  else 
than  a  mass  of  cells,  wherein  no  distinction  of  parts  has  as  yet  manifested  itself; 
and  that  the  production  of  two  complete  individuals,  only  held  together  by  a 
connecting  band,  may  arise  from  some  cause  which  determines  the  subdivision 
of  the  germinal  mass,  at  the  period  when  its  grade  of  development  corresponds 
with  that  of  the  Hydra  or  Planaria.1  And  this  view  of  the  case  is  confirmed 
by  the  facts  already  stated  (§  599),  in  regard  to  the  higher  degree  of  the  re- 
generating power  during  embryonic  life,  infancy,  and  childhood,  as  compared 
with  that  which  remains  after  the  development  of  the  fabric  has  been  completed. 
955.  We  have  now  to  consider,  however,  the  proper  act  of  Generation,  which 
uniformly  involves  the  union  of  the  contents  of  two  peculiar  cells,  which  may 
be  designated  "sperm-cells/'  and  " germ-cells."3  Recent  discoveries  render  it 
almost  certain  that  this  true  generative  process  occurs  throughout  the  Vegetable 
kingdom,  and  is  not  confined,  as  was  formerly  supposed,  to  Flowering  Plants.3 
It  appears  to  take  place  in  three  modes ;  which  are  all,  however,  but  variations 
of  one  fundamental  plan  :  1.  In  the  simplest  Cellular  Plants,  in  which  every 
cell  appears  to  possess  the  same  endowments,  so  that  there  is  no  kind  of  special- 
ization of  function,  the  generative  act  consists  in  the  "conjugation"  of  two  of 
the  ordinary  cells,  between  which  no  difference  can  be  traced.  In  what  may  be 
considered  the  lowest  types  of  this  process,  both  cells  discharge  their  contents, 
and  the  new  body  or  sporangium  is  formed  between  them  by  the  mixture  of 
their  "endochromes;"  each  cell  appearing  to  have  precisely  the  same  share  in 
the  process,  so  that  no  distinction  of  "  sperm-cells"  and  "  germ-cells"  can  be 
said  here  to  exist.  This,  however,  is  precisely  what  might  be  expected,  when  it  is 
remembered  that  no  distinction  presents  itself  between  any  other  organs,  such  as 
the  root  and  leaf;  each  cell  having  endowments  to  all  appearance  identical  with 
those  of  the  rest  of  the  mass.  But  the  generative  process,  in  this  which  may 
be  regarded  as  its  simplest  and  most  essential  form,  shows  itself  to  be  the  pre- 
cise counterpart  of  the  process  of  "fission"  already  described  (§  104);  for  as 
in  the  latter  one  cell  divides  itself  into  equal  halves,  between  which  no  difference 
can  be  traced,  so,  in  the  act  of  "  conjugation,"  the  contents  of  two  cells,  ap- 

1  See  Prof.  Allen  Thomson  on  "Double  Monstrosity,"  in  the  "Edinb.  Monthly  Journ.," 
June  and  July,  1844;  and  Prof.  Vrolik's  Article  "  Teratology"  in  the  "Cyclop,  of  Anat 
and  Phys.,"  vol.  iv. 

2  These  terms  are  adopted  from  Prof.  Owen.     See  his  "  Lectures  on  Parthenogenesis," 
London,  1849. 

3  For  a  general  account  of  these  discoveries,  see  the   "British  and  Foreign  Medico- 
Chirurgical  Review,"  Oct.  1849;  and  "  Princ.  of  Phys.,  Gen.  and  Comp.,"  CHAP,  xvin., 
Am.  Ed. 


950 


OF   GENERATION. 


parently  similar,  reunite,  and  form  but  a  single  new  cell  between  them.  In 
virtue  of  that  union,  a  new  force  seems  to  be  developed,  which  leads  to  the 
multiplication  of  this  first  cell  by  repeated  subdivision,  until  the  germ-force  is 
expended,  when  a  fresh  conjugation  occurs.  This  reunion  of  the  cell  contents 
may  take  place,  either  by  the  rupture  of  both  cells  and  the  discharge  of  their 
endochromes,  around  which,  after  their  admixture,  a  new  cell-wall  is  formed 
(Fig.  236,  A,  1),  or  by  the  formation  of  a  direct  communication  from  the  interior 
of  one  to  that  of  the  other;  in  which  latter  case  the  union  of  the  two  endo- 
chromes  may  take  place  either  in  the  connecting  channel  (A,  2),  or  in  one  of 
the  cells  of  the  pair  (A,  3),  within  which  the  sporangium  is  formed  and  matured. 
It  is  in  certain  of  the  Desmideae  and  Zygnemata  that  we  meet  with  this  latter 
type  j  which  presents  us  with  the  first  distinction  between  the  "sperm-cell"  and 
the  "  germ-cell." — 2.  In  the  higher  Algae,  and  in  all  the  superior  Cryptogamia,  the 
process  is  effected  by  the  agency  of  moving  filaments,  precisely  resembling  the 
spermatozoa  of  Animals,  and  developed  within  special  "  sperm-cells"  in  a  mode 
precisely  the  same  with  the  evolution  of  the  spermatozoa  of  Animals  (§  959) ; 
these  appear  to  find  their  way  to  the  germ-cells,  which  are  sometimes  developed 
within  the  same  receptacles,  sometimes  in  distinct  receptacles  on  the  same  plant, 
and  sometimes  in  different  plants ;  and  as  the  result  of  their  contact  with  the 
germ-cells,  the  embryo  originates  in  the  interior  of  the  latter  (Fig.  236,  B). 
This  embryo,  in  the  lower  Cryptogamia,  is  at  once  cast  upon  its  own  resources; 


-QttO- 


Diagram  representing  the  three  principal  forms  of  the  Generative  Process  in  Plants :  A,  conjugation  of  inferior 
Cryptogamia;  formation  of  the  sporangium,  b,  by  admixture  of  the  discharged  endochromes  of  the  parent- 
cells,  a,  a.  2,  production  of  the  sporangium,  6,  within  a  dilatation  formed  by  the  union  of  the  two  parent-cells. 
3,  production  of  the  sporangium,  6,  by  the  passage  of  the  endochrome  of  cell  a  into  that  of  cell  a*,  marking 
out  a  sexual  difference.  B,  fertilization  of  germ  in  higher  Cryptogamia;  a,  sperm-cell  discharging  its  spiral 
filament ;  a*,  germ-cell,  against  which  one  of  these  filaments  is  impinging ;  6,  germ  produced  by  their  con- 
tact. C,  fertilization  of  germ  in  Phanerogamia;  a,  sperm-cell,  or  pollen-grain,  sending  its  prolonged  tube 
down  the  style,  until  it  reaches  a*,  the  germ-cell,  inclosed  in  the  ovule,  the  section  of  whose  coats  is  shown 
at  c;  from  the  contact  of  the  two,  is  produced  the  germ  b. 

whilst  in  the  higher  it  is  nourished,  during  its  early  development,  by  food  sup- 
plied to  it  by  the  parent.  In  no  case,  however,  does  the  parent  appear  to  furnish 
that  accumulation  of  nutritive  matter  for  the  development  of  the  product  of  the 
germ-cell,  which,  when  included  in  a  common  envelop  with  it,  would  constitute 
a  true  "seed." — 3.  In  the  Flowering  Plants,  the  "sperm-cell"  (or  pollen -grain) 
does  not  evolve  a  self-moving  filament,  as  in  the  Cryptogamia;  but  puts  forth  a 
long  tube,  which,  insinuating  itself  between  the  soft  loose  tissue  of  the  "style," 


ACTION   OF   THE    MALE.  951 

conveys  the  fertilizing  influence  to  the  "germ-cell"  (or  embryonic  vesicle'  of 
the  ovule)  after  a  different  fashion  (Fig.  236,  c) ;  still,  however,  fulfilling  the 
same  essential  purpose  as  that  which  the  simple  "  conjugation"  of  the  lowest 
Algae  effected,  namely,  the  mingling  of  the  contents  of  the  "sperm-cell"  and 
"germ-cell,"  which  takes  place  by  transudation  through  the  thin  membranes  of 
the  pollen-tube  and  of  the  embryonic  vesicle.  The  germ-cell  is  here  surrounded 
by  a  mass  of  nutritious  matter,  which,  with  the  embryo,  constitutes  the  "seed;" 
and  it  is  upon  this  store,  that  the  young  plant  subsists  during  the  early  stages 
of  its  development. 

956.  The  "  act  of  Generation"  in  animals  may  be  said  to  combine  the  prin- 
cipal features  of  the  second  and  third  of  the  above  methods  j  for,  as  in  the 
higher  Cryptogamia,  the  "  sperm-cells"  of  Animals  seem  invariably  to  form  the 
self-moving  filaments  known  as  Spermatozoa  j  whilst  the  "  germ-cells,"  instead 
of  being  naked  (as  in  the  Cryptogamia),  are  surrounded  (as  in  Flowering  Plants) 
by  a  mass  of  nutriment  destined  to  serve  for  the  early  development  of  the  em- 
bryo ;  this  mass  with  its  contained  germ-cell  being  known  as  the  ovule  before  it 
has  been  fertilized,  and  as  the  ovum  or  egg  after  fecundation  has  taken  place. 
There  is  a  great  difference,  however,  among  the  different  tribes  of  Animals,  as 
to  the  degree  of  assistance  thus  afforded  to  the  embryo  ;  the  general  rule  being, 
that  the  higher  the  form  which  the  embryo  is  ultimately  to  attain,  the  longer  is 
it  supported  by  its  parent.  Hence  we  find  the  embryos  of  most  Invertebrated 
animals  coming  forth  from  the  egg  in  a  condition  very  much  unlike  their  perfect 
type,  and  only  acquiring  this  after  a  long  succession  of  subsequent  alterations, 
which  frequently  involve  a  complete  change  of  form,  or  metamorphosis.  In 
Fishes,  however,  the  embryo,  though  far  from  having  completed  its  embryonic 
development  at  the  time  of  its  emersion  from  the  egg,  does  not  differ  so  widely 
from  the  adult  type.  In  Birds,  there  is  a  provision  for  a  much  more  advanced 
development  j  the  store  of  nutritious  matter,  or  "  yelk,"  being  so  large  as  to 
allow  the  whole  series  of  changes  requisite  for  the  formation  of  the  complete 
chick  to  take  place  before  it  leaves  the  egg.  In  the  Mammalia,  on  the  contrary, 
the  quantity  of  yelk  contained  in  the  ovum  is  very  small,  but  the  embryo  is 
only  dependent  upon  it  for  the  materials  of  its  increase  during  the  earliest 
stages  of  its  evolution  ;  for  it  speedily  forms  a  special  connection  with  the  pa- 
rent structure,  by  means  of  which  it  is  enabled  to  receive  a  continual  supply  of 
newly-prepared  aliment,  so  as  to  be  supported  at  the  expense  of  this  until  far 
advanced  in  its  development.  Some  approaches  to  this  arrangement  are  met 
with  among  certain  of  the  lower  Animals,  but  it  is  only  in  the  higher  Mam- 
malia that  it  is  completely  carried  out  \  and  it  is  only  in  this  class,  too,  that  we 
find  a  supplemental  provision  for  the  nutrition  of  the  offspring  after  it  has  come 
forth  into  the  world.  In  many  of  the  lower  tribes  of  Animals,  the  fertilization 
of  the  ova  is  accomplished  without  any  sexual  congress ;  the  spermatic  fluid 
effused  by  the  male  coming  into  direct  contact  with  the  ova  previously  deposited 
by  the  female ;  but  in  all  the  higher  tribes,  as  in  Man,  the  spermatic  fluid  is 
conveyed  into  the  oviducts  of  the  female,  that  it  may  impregnate  the  ovum 
shortly  after  it  has  quitted  the  ovarium,  or  even  before  its  final  escape  from  it. 
— With  these  general  views,  we  shall  now  be  prepared  to  examine  into  the  his- 
tory of  the  act  of  Generation  in  Man,  and  to  consider  the  share  which  each  sex 
has  in  its  performance. 

2. — Action  of  the  Male. 

95V.  The  Spermatic  fluid  of  the  Male  is  secreted  by  glandular  organs,  known 
as  Testes.  Each  of  these  consists  of  several  lobules  which  are  separated  from 
each  other  by  processes  of  the  Tunica  Albuginea  that  pass  down  between  them, 
and  also  by  an  extremely  delicate  membrane  (described  by  Sir  A.  Cooper  under 


952 


OP   GENERATION. 


the  name  of  Tunica  Vasculosa)  consisting  of  minute  ramifications  of  the 
spermatic  vessels  united  by  areolar  tissue.  Each  lobule  is  composed  of  a  mass 
of  convoluted  tubuli  seminiferi,  throughout  which  bloodvessels  are  minutely 
distributed.  The  lobules  differ  greatly  in  size,  some  containing  one,  and  others 


Fig.  237. 


Fig.  238. 


The  Testicle  injected  with  mercury :  1,  tunica 
albuginea ;  2,  seminiferous  tubes ;  3,  the  rete  vas- 
culosum  testis ;  4,  a  globule  of  mercury  which  has 
ruptured  the  tubes ;  5,  the  vasa  efferentia  which 
form  the  coni  vasculosi ;  6,  coni  vasculosi  form- 
ing the  head  of  the  epididymis ;  7,  epididymis ;  8, 
globus  minor  of  the  epididymis  ;  ! 


A  view  of  the  minute  structure  of  the  Testis :  1,  1, 
tunica  albuginea ;  2  2,  corpus  Highmorianum ;  3,  3,  tu- 
buli  seminiferi  convoluted  into  lobules ;  4,  vasa  recta ;  5, 
rete  testis  ;  6,  vasa  efferentia ;  7,  coni  vasculosi  consti- 
tuting the  globus  major  of  the  epididymis;  8,  body  of 
the  epididymis ;  9,  its  globus  minor ;  10,  vas  deferens  ; 
11,  vasculum  aberrans,  or  blind  duct. 

many  of  the  tubuli ;  the  total  number  of  the  lobules  is  estimated  at  about  450 
in  each  testis,  and  that  of  the  tubuli  at  840.  The  convolutions  of  the  tubuli 
are  so  arranged,  that  each  lobule  forms  a  sort  of  cone,  the  apex  of  which  is  di- 
rected towards  the  Rete  Testis.  It  is  difficult  to  trace  the  free  extremities  of 
the  Seminiferous  tubes,  owing  to  the  frequency  of  their  anastomoses  with  each 
other ;  in  this  respect,  therefore,  the  structure  of  the  testis  accords  closely  with 
that  of  the  Kidney.  The  diameter  of  the  tubuli  is,  for  the  most  part,  very  uni- 
form; in  the  natural  condition  they  seem  to  vary  from  about  the  l-195th  to  the 
l-170th  of  an  inch  ;  but  when  injected  with  mercury,  they  are  distended  to  a 
size  nearly  double  the  smaller  of  these  dimensions.  When  they  have  reached 
to  within  a  line  or  two  of  the  rete  testis,  they  cease  to  be  convoluted,  several 
unite  together  into  tubes  of  larger  diameter,  and  these  enter  the  rete  testis  under 
the  name  of  tubuli  recti.  The  rete  testis  consists  of  from  seven  to  thirteen  ves- 
sels, which  run  in  a  waving  course,  anastomose  with  each  other,  and  again  divide, 
being  all  connected  together.  The  vasa  efferentia  which  pass  to  the  head  of 
the  epididymis  are  at  first  straight,  but  soon  become  convoluted,  each  forming  a 
sort  of  cone,  of  which  the  apex  is  directed  towards  the  rete  testis,  the  base  to 
the  head  of  the  epididymis.  The  number  of  these  is  stated  to  vary  from  nine 
to  thirty ;  and  their  length  to  be  about  eight  inches.  The  epididymis  itself 
consists  of  a  very  convoluted  canal,  the  length  of  which  is  about  twenty-one 
feet.  Into  its  lower  extremity,  that  is,  the  angle  which  it  makes  where  it  termi- 
nates in  the  vas  deferens,  is  poured  the  secretion  of  the  vasculum  aberrans  or 


ACTION   OF   THE    MALE. 


953 


appendix ;  which  seems  like  a  testis  in  miniature,  closely  resembling  a  single 
lobule  in  its  structure.     Its  special  function  is  unknown. — The  fluid  secreted  by 

Fig.  239. 


Human  Testis,  injected  with  mercury  as  completely  as  possible :  1, 1,  lobules  formed  of  the  seminiferous 
tubes ;  2,  rete  testis ;  3,  vasa  efferentia ;  4,  flexures  of  the  efferent  vessels  passing  into  the  head,  5,  5,  of  the 
epididymis ;  6,  body  of  the  epididymis  ;  7,  appendix ;  8,  cauda ;  9,  vas  deferens. 

the  Testis  is  thick,  tenacious,  and  of  a  grayish  or  yellowish  color.  It  is  mingled, 
during  or  before  emission,  with  fluid  secreted  by  the  Prostate,  Cowper's  gland, 
&c. ;  and  it  cannot,  therefore,  be  obtained  pure  but  by  drawing  it  from  the  tes- 

Fig.  240. 


Plan  of  the  structure  of  the  Testis  and  Epididymis  :  a,  a,  seminiferous  tubes  ;  a*  ,  a* ,  their  anastomoses; 
a,  lobules  formed  of  the  seminiferous  tubes;  b,  rete  testis;  c,  vasa  efferentia;  d,  flexures  of  the  efferent  vessels 
passing  into  the  head,  e,  e,  of  the  epididymis;/,  body  of  the  epididymis;  ^appendix;  h,  cauda;  t'3vas  deferens. 


954  OP   GENERATION. 

ticle  itself;  hence  no  accurate  analysis  can  be  made  of  it  in  the  Human  sub- 
ject. The  peculiar  odor  which  the  Semen  possesses  does  not  appear  to  belong 
to  the  proper  spermatic  fluid ;  but  is  probably  derived  from  one  or  other  of  the 
secretions  with  which  it  is  mingled.  The  chemical  analyses  which  have  been 
made  of  this  fluid  are  all  defective,  inasmuch  as  they  do  not  distinguish  the 
real  secretion  of  the  testes  from  the  mucus,  prostatic  fluid,  &c.,  with  which  it  is 
mingled.  It  may  be  stated,  however,  that  it  has  an  alkaline  reaction,  and  con- 
tains albumen,  with  a  peculiar  animal  principle  termed  Spermatin ;  and  also 
saline  matter,  consisting  chiefly  of  muriates  and  phosphates,  especially  the  lat- 
ter, which  form  crystals  when  the  fluid  has  stood  for  some  little  time. 

958.  The  essential  peculiarity  of  the  Spermatic  fluid  consists  in  the  presence 
of  a  large  number  of  very  minute  bodies,  only  discernible  with  a  high  power 
of  the  Microscope ;  and  these,  in  ordinary  cases,  remain  in  active  motion  for 
some  time  after  they  have  quitted  the  living  organism.     The  Human  Sperma- 
tozoon (of  which  representations  are  given  in  Plate  I.,  Fig.  1)  consists  of  a  little 
oval  flattened  "  body"  between  the  l-600th  and  the  l-800th  of  a  line  in  length, 
from  which  proceeds  a  long  filiform  "tail,"  gradually  tapering  to  the  finest  point, 
of  l-50th  or  at  most  l-40th  of  a  line  in  length.     The  whole  is  perfectly  trans- 
parent; and  nothing  that  can  be  termed  structure  can  be  satisfactorily  distin- 
guished within  it.     Its  movements  are  principally  executed  by  the  tail,  which 
has  a  kind  of  vibratile  undulating  motion.     They  may  continue  for  many  hours 
after  the  emission  of  the  fluid;  and  they  are  not  checked  by  its  admixture  with 
other  secretions,  such  as  the  urine  and  the  prostatic  fluid.     Thus,  in  cases  of 
nocturnal  emission,  the  Spermatozoa  may  not  unfrequently  be  found  actively 
moving  through  the  urine  in  the  morning ;  and  those  contained  in  the  seminal 
fluid  collected  from  females  that  have  just  copulated,  are  frequently  found  to 
live  many  days.     Their  presence  maybe  readily  detected  by  a  Microscope- of 
sufficient  power,  even  when  they  have  long  ceased  to  move,  and  are  broken  into 
fragments;  and  the  Physician  and  the  Medical  Jurist  will  frequently  derive 
much  assistance  from  an  examination  of  this  kind.     Thus,  cases  are  of  no  un- 
common occurrence,  especially  among  those  who  have  been  too  much  addicted 
to  sexual  indulgence,  in  which  seminal  emissions  take  place  unconsciously  and 
frequently,  and  produce  great  general  derangement  of  the  health ;  and  the  true 
nature  of  the  complaint  is  obscure,  until  the  fact  has  been  detected  by  ocular 
examination.     Again,  in  charges  of  rape,  in  which  evidence  of  actual  emission 
is  required,  a  microscopic  examination  of  the  stiffened  spots  left  on  the  linen 
will  seldom  fail  in  obtaining  proof,  if  the  act  have  been  completed :  in  such 
cases,  however,  we  must  not  expect  to  meet  with  more  than  fragments  of  Sper- 
matozoa; but  these  are  so  unlike  anything  else,  that  little  doubt  need  be  enter- 
tained regarding  them.     It  has  been  proposed  to  employ  the  same  test  in  juri- 
dical inquiries  respecting  doubtful  cases  of  death  by  suspension,  seminal  emis- 
sions being  not  unfrequent  results  of  this  kind  of  violence;  but  there  are  many 
obvious  objections  which  should  prevent  much  confidence  being  placed  in  it.1 

959.  The  mode  of  evolution  of  the  Spermatozoa,  first  discovered  by  Wagner, 
and  more  perfectly  elucidated  by  Kolliker,  is  such  as  to  indicate  that  these 
bodies  are  true  products  of  the  formative  action  of  the  organs  in  which  they 
are  found,  and  cannot  be  ranked  (as  they  long  were)  in  the  same  category  with 
Animalcules.     They  are  developed  in  the  interior  of  cells,  or  "  vesicles  of  evo- 
lution," such  as  are  visible  in  the  seminal  fluid  in  various  stages  of  develop- 
ment (Plate  I.,  Fig.  2,  A,  B,  c),  and  have  been  known  under  the  name  of 
"  seminal  granules."     These  appear  to  have  been  themselves  formed  within 
parent-cells,  which  are  probably  to  be  regarded  as  the  epithelial  cells  of  the 

1  See  the  Author's  Article  "  Asphyxia,"  in  the  "Library  of  Practical  Medicine,"  and 
tfie  authorities  there  referred  to. 


ACTION   OF   THE    MALE.  955 

tubuli  seminiferi;  constituting,  like  the  analogous  cells  of  other  glands,  the 
essential  elements  of  the  spermatic  apparatus.1  These  parent-cells  are  some- 
times observed  to  contain  but  a  single  u  vesicle  of  evolution,"  as  shown  at  D  ; 
but  more  commonly  three,  four,  six,  or  seven  are  to  be  seen  within  them  (E). 
When  taken  from  a  body  recently  dead,  and  examined  without  being  treated 
with  water  or  any  other  agent,  they  are  quite  pellucid,  and  exhibit  a  delicate 
contour,  with  perfectly  homogeneous  contents ;  very  speedily,  however,  a  sort 
of  coagulation  takes  place  within  them,  by  which  their  contents  are  rendered 
granular.  Each  of  these  "vesicles  of  evolution"  gives  origin  to  a  spermato- 
zoon, and  to  one  only  ;  the  earliest  stages  of  its  development  have  not  yet  been 
distinctly  made  out,  since  it  does  not  at  first  exhibit  those  sharp  distinct  con- 
tours, dependent  on  its  great  refractive  power,  which  afterwards  distinguish  it ; 
but  it  is  seen  lying  i^  the  interior  of  the  cell  as  a  slight  linear  shadow,  at 
first  partly  hidden  by  the  surrounding  granules  (Fig.  3,  B),  but  afterwards 
without  any  such  obscuration.  When  the  vesicle  is  completely  matured,  it 
bursts,  and  gives  exit  to  the  contained  spermatozoon,  which,  thenceforth,  in  the 
Mammalia,  usually  moves  freely  in  the  spermatic  fluid ;  in  Birds,  however,  it  is 
more  common  for  the  parent-cells  to  retain  the  vesicles  of  evolution  during  the 
development  of  the  Spermatozoa  within  the  latter ;  so  that  when  these  set  free 
the  Spermatozoa,  they  are  still  enveloped  by  the  parent-cell.  In  this  condition 
they  have  a  tendency  to  aggregation  in  bundles;  and  these  bundles  are  finally 
liberated  by  the  rupture  of  the  parent-cell,  after  which  the  individual  sperma- 
tozoa separate  from  one  another.  Such  bundles  may  be  occasionally  seen  in 
the  Human  semen. — That  the  Spermatozoa  are  the  essential  elements  of  the 
spermatic  fluid,  may  be  reasonably  inferred  from  several  considerations.  There 
are  some  cases  in  which  the  "  liquor  seminis"  is  altogether  absent,  so  that  they 
constitute  the  sole  element  of  the  semen ;  whilst,  on  the  other  hand,  they  are 
never  wanting  in  the  semen  of  animals  capable  of  procreation ;  but  are  absent, 
or  imperfectly  developed,  in  the  semen  of  hybrids,  which  are  nearly  or  entirely 
sterile.  Moreover,  we  have  every  reason  to  believe  that,  in  the  higher  animals, 
the  absolute  contact  of  the  spermatozoa  with  the  ovum  is  requisite  for  its  fecun- 
dation ;  whilst,  on  the  other  hand,  if  the  spermatozoa  be  carefully  removed  from 
the  liquor  seminis  by  filtration,  the  latter  is  found  to  be  entirely  destitute  of 
fertilizing  power.2 — It  is  interesting  to  remark  that  the  perfectly  developed 
spermatozoa  possess  the  same  chemical  composition  with  the  epithelial  tissues  in 
general.3 

960.  The  power  of  procreation  does  not  usually  exist  in  the  Human  Male, 
until  the  age  of  from  14  to  16  years ;  and  it  may  be  considered  probable  that 
no  Spermatozoa  are  produced  until  that  period,  although  a  fluid  is  secreted  by 
the  testes.  At  this  epoch,  which  is  ordinarily  designated  as  that  of  Puberty,  a 
considerable  change  takes  place  in  the  bodily  constitution :  the  sexual  organs 
undergo  a  much-increased  development;  various  parts  of  the  surface,  especially 
the  chin  and  the  pubes,  become  covered  with  hair;  the  larynx  enlarges,  and 
the  voice  becomes  lower  in  pitch,  as  well  as  rougher  and  more  powerful;  and 
new  feelings  and  desires  are  awakened  in  the  mind.  Instances,  however,  are 
by  no  means  rare,  in  which  these  changes  take  place  at  a  much  earlier  period; 
the  full  development  of  the  generative  organs,  with  manifestations  of  the  sexual 

1  In  the  Hydra  and  other  Zoophytes,  such  cells  are  found  imbedded  in  the  general 
substance  of  the  body,  instead  of  being  developed  within  a  special  organ. 

2  This  point  has  been  completely  established  by  the  researches  of  Mr.  Newport  ("Phil. 
Trans.,"  1851),  who  has  repeated  and  confirmed  the  experimental  results  previously  ob- 
tained by  Spallanzani  and  by  Prevost  and  Dumas. 

8  For  the  latest  researches  on  the  development,  &c.,  of  the  Spermatozoa,  see  the  elabo- 
rate Article  "Semen,"  in  the  "Cyclop,  of  Anat.  and  Physiol.,"  by  Drs.  Wagner  and 
Leuckardt. 


956  OP   CxENERATION. 

passion,  having  been  observed  in  children  of  but  a  few  years  old.  The  procre- 
ative  power  may  last,  if  not  abused,  during  a  very  prolonged  period.  Un- 
doubted instances  of  virility  at  the  age  of  more  than  100  years  are  on  record ; 
but  in  these  cases,  the  general  bodily  vigor  was  preserved  in  a  very  remarkable 
degree.  The  ordinary  rule  seems  to  be  that  sexual  power  is  not  retained  by 
the  male  to  any  considerable  amount,  after  the  age  of  60  or  65  years. — To  the 
use  of  the  sexual  organs  for  the  continuance  of  his  race,  Man  is  prompted  by  a 
powerful  instinctive  desire  (§  772),  which  he  shares  with  the  lower  animals. 
This  Instinct,  like  the  other  propensities,  is  excited  by  sensations;  and  these 
may  either  originate  in  the  sexual  organs  themselves,  or  may  be  excited  through 
the  organs  of  special  sensation.  Thus  in  Man  it  is  most  powerfully  aroused 
by  impressions  conveyed  through  the  sight  or  the  touch;  but  in  many  other 
animals,  the  auditory  and  olfactive  organs  communicate  impressions  which  have 
an  equal  power;  and  it  is  not  improbable  that,  in  certain  morbidly-excited 
states  of  feeling,  the  same  may  be  the  case  in  ourselves.  That  local  impressions 
have  also  a  very  powerful  effect  in  exciting  sexual  desire,  must  have  been  within 
the  experience  of  almost  every  one ;  the  fact  is  most  remarkable,  however,  in 
cases  of  Satyriasis,  which  disease  is  generally  found  to  be  connected  with  some 
obvious  cause  of  irritation  of  the  generative  system,  such  as  pruritus,  active 
congestion,  &c.  That  some  part  of  the  Encephalon  is  the  seat  of  this  as  of 
other  instinctive  propensities,  appears  from  the  considerations  formerly  ad- 
duced; but  that  the  Cerebellum  is  the  part  in  which  this  function  is  specially 
located,  cannot  be  regarded  as  by  any  means  sufficiently  proved  (§§  707 — 772). 
The  instinct,  when  once  aroused  (even  though  very  obscurely  felt),  acts  upon 
the  mental  faculties  and  moral  feelings ;  and  thus  becomes  the  source,  though 
almost  unconsciously  so  to  the  individual,  of  the  tendency  to  form  that  kind  of 
attachment  towards  one  of  the  opposite  sex  which  is  known  as  love.  This  tend- 
ency cannot  be  regarded  as  a  simple  passion  or  emotion,  since  it  is  the  result 
of  the  combined  operations  of  the  reason,  the  imagination,  and  the  moral  feel- 
ings ;  and  it  is  in  this  engraftment  (so  to  speak)  of  the  psychical  attachment, 
upon  the  mere  corporeal  instinct,  that  a  difference  exists  between  the  sexual 
relations  of  Man  and  those  of  the  lower  animals.  In  proportion  as  the  Human 
being  makes  the  temporary  gratification  of  the  mere  sexual  appetite  his  chief 
object,  and  overlooks  the  happiness  arising  from  spiritual  communion,  which  is 
not  only  purer  but  more  permanent,  and  of  which  a  renewal  may  be  anticipated 
in  another  world — does  he  degrade  himself  to  the  level  of  the  brutes  that  perish. 
Yet  how  lamentably  frequent  is  this  degradation  ! 

961.  When  impelled  by  sexual  excitement,  the  Male  seeks  intercourse  with 
the  Female,  the  erectile  tissue  of  the  genital  organs  becomes  turgid  with  blood 
(§  534),  and  the  surface  acquires  a  much  increased  sensibility ;  this  is  especially 
acute  in  the  Glans  penis.  By  the  friction  of  the  Glans  against  the  rugous  walls 
of  the  Vagina,  the  excitement  is  increased;  and  the  impression  which  is  thus 
produced  at  last  becomes  so  strong,  that  it  calls  forth,  through  the  medium  of 
the  Spinal  Cord,  a  reflex  contraction  of  the  muscles  which  surround  the  Vesi- 
culae  Seminales.  These  receptacles  discharge  their  contents  (partly  consisting 
of  semen  and  partly  of  a  secretion  of  their  own)  into  the  Urethra;  and  from 
this  they  are  expelled  with  some  degree  of  force,  and  with  a  kind  of  convulsive 
action,  by  its  own  Compressor  muscles.  Now  although  the  sensations  con- 
cerned in  this  act  are  ordinarily  most  acutely  pleasurable,  there  appears  suffi- 
cient evidence  that  they  are  by  no  means  essential  to  its  performance ;  and  that 
the  impression  which  is  conveyed  to  the  Spinal  Cord  need  not  give  rise  to  a 
sensation,  in  order  to  produce  the  reflex  contraction  of  the  Ejaculator  muscles 
(§  723).  The  high  degree  of  nervous  excitement  which  the  act  of  coition  in- 
volves produces  a  subsequent  depression  of  corresponding  amount;  and  the  too 
frequent  repetition  of  it  is  productive  of  consequences  very  injurious  to  the 


ACTION   Oi1   THE   FEMALE. 


957 


general  health.  This  is  still  more  the  case  with  the  solitary  indulgence,  which 
(it  is  to  be  feared)  is  practised  by  too  many  youths  ;  for  this,  substituting  an 
unnatural  degree  of  one  kind  of  excitement  for  that  which  is  wanting  in  another, 
cannot  but  be  still  more  trying  to  the  bodily  powers.  The  secretion  of  seminal 
fluid  being,  like  other  secretions,  very  much  under  the  control  of  the  nervous 
system,  will  be  increased  by  the  continual  direction  of  the  mind  towards  objects 
which  awaken  the  sexual  propensity  (§  948,  note);  and  thus,  if  intercourse  be 
very  frequent,  a  much  larger  quantity  will ;  altogether  be  produced,  although 
the  amount  emitted  at  each  period  will  be  less.  The  formation  of  the  secretion 
seems  of  itself  to  be  a  much  greater  tax  upon  the  corporeal  powers  than  might 
have  been  supposed  d  priori :  and  it  is  a  well-known  fact  that  the  highest 
degree  of  bodily  vigor  is  inconsistent  with  more  than  a  very  moderate  indulg- 
ence in  sexual  intercourse  ;  whilst  nothing  is  more  certain  to  reduce  the  powers, 
both  of  body  and  mind,  than  excess  in  this  respect.  These  principles,  which 
are  of  great  importance  in  the  regulation  of  the  health,  are  but  results  of  the 
general  law,  which  prevails  equally  in  the  Vegetable  and  Animal  kingdoms — 
that  the  Development  of  the  Individual,  and  the  Reproduction  of  the  Species, 
stand  in  an  inverse  ratio  to  each  other. 


3. — Action  of  the  Female.          „ 

962.  The  essential  part  of  the  Female  Generative  system  is  that  in  which 
the  Ova  are  prepared;  the  other  organs  are  merely  accessory,  and  are  not  to  be 
found  in  a  large  proportion  of  the  Animal  kingdom.  In  many  of  the  lower 
animals,  the  Ovaria  and  Testes  are  so  extremely  like  each  other,  that  the  dif- 
ference between  them  can  scarcely  be  distinguished ;  and  the  same  is  true  re- 
garding the  condition  of  these  organs  in  Man,  at  an  early  period  of  development. 
The  fact  is  one  of  no  small  interest.  In  many  of  the  lower  animals,  the  Ovarium 
consists  of  a  loose  tissue  containing  many  cells,  in  which  the  Ova  are  formed, 
and  from  which  they  escape  by  the  rupture  of  the  cell-walls ;  in  the  higher 
animals,  as  in  the  Human  female,  the  tissue  of  the  Ovarium  is  more  compact, 
forming  what  is  known  as  the  stroma  ;  and  the  Ova,  except  when  they  are  ap- 
proaching maturity,  can  only  be  distinguished  in  the  interstices  of  this,  by  the 

Fig.  241. 


Diagram  of  a  Graafian  vesicle,  containing  an  ovum :  1.  Stroma  or  tissue  of  the  ovary.  2  and  3.  External 
and  internal  tunics  of  the  Graafian  vesicle.  4.  Cavity  of  the  vesicle.  5.  Thick  tunic  of  the  ovum,  or  yelk- 
sac.  6.  The  yelk.  7.  The  germinal  vesicle.  8.  The  germinal  spot. 

aid  of  a  high  magnifying  power.  The  Ovum  in  all  Vertebrated  animals  is  pro- 
duced within  a  '  capsule  or  bag,  the  exterior  of  which  is  in  contact  with  the 
stroma  of  the  ovarium ;  this  has  been  termed,  in  Mammalia,  the  Graafian  vesick, 


958  OF   GENERATION. 

after  the  name  of  its  first  discoverer ;  but  the  more  general  and  appropriate 
designation  of  Ovisac  has  been  given  to  it  by  Dr.  Barry,  who  has  shown  that 
it  exists  in  other  classes  of  Vertebrata.  Between  the  Ovum  and  the  Ovisac,  in 
Oviparous  animals,  there  is  scarcely  any  interval ;  but  in  the  Mammalia,  a  large 
amount  of  granular  matter  (composed  of  nucleated  cells,  loosely  aggregated  toge- 
ther) is  present ;  being  especially  found  adherent  to  the  lining  of  the  jovisac,  to 
which  it  forms  a  sort  of  epithelium,  or  internal  tunic,  known  as  the  membrana 
granulosa;  whilst  it  also  forms  a  disk-like  investment  to  the  ovum,  which  is 
termed  the  discus  proligerus.  The  membrane  which  incloses  the  yelk  in  Mam- 
malia has  received,  on  account  of  its  thickness  and  peculiar  transparency,  the 
distinctive  appellation  of  zona  pellucida  (Fig.  242,  m  v). — The  yolk,  or  vitellus 
(j"),  which  is  composed  of  albumen  and  oil-particles,  with  traces  of  cells,  is 
very  small  in  the  Mammalian  ovum,  its  function  being  limited  to  the  sustenance 
of  the  germ  during  its  earliest  period  of  development ;  and  it  corresponds  rather 
with  that  part  of  the  yelk  of  the  egg  of  the  higher  Ovipara  which  has  been  dis- 
tinguished as  the  "  germ-yelk/'  in  consequence  of  its  direct  participation  in 
the  formation  of  the  germinal  substance  than  with  that  which  has  been 
termed  the  "  food-yelk,"  as  not  being  incorporated  with  the  germ,  but  being 
destined  for  its  subsequent  nutrition  by  undergoing  conversion  into  blood.1 
Occupying  the  centre  of  the  vitelline  mass,  in  the  immature  ovulum,  is  a  pecu- 
liar cell,  very  different  in  its  aspect  from  the  surrounding  substance,  which  is 
termed  the  germinal  vesicle  (Fig.  242,  v  <?)  ;  and  this  has  a  very  distinct  nucleus 
(t  g)  known  as  the  germinal  spot.  This  cell  must  be  considered  as  the  essential 
part  of  the  ovum,  and  as  homologous  with  the  "  germ-cell"  or  "  embryonic  vesicle" 
of  the  Vegetable  ovule. — The  Human  Ovum  is  extremely  minute ;  not  measur- 
ing above  l-120th  of  an  inch  in  diameter,  and  being  sometimes  of  no  more  than 

Fig.  242. 


Constituent  parts  of  Mammalian  Ovum :  A,  entire ;  B,  ruptured,  with  the  contents  escaping ; — m  v,  vitelline 
membrane ;  j,  yelk ;  v  g,  germinal  vesicle ;  t  g,  germinal  spot. 

half  that  size.  The  diameter  of  the  germinal  vesicle  of  the  human  ovum  has 
not  yet  been  ascertained,  owing  to  the  difficulty  of  isolating  it  from  the  yelk ;  in 
the  ovum  of  the  rabbit,  it  is  about  l-720th  of  an  inch ;  and  that  of  the  ger- 
minal spot,  in  the  Mammalia  generally,  is  from  l-3600th  to  l-2400th  of  an  inch. 
963.  It  appears,  from  the  researches  of  Valentin  and  Bischoff,  that  the 
Graafian  vesicle,  or  Ovisac,  is  formed  previously  to  the  Oyum,  which  is  subse- 
quently developed  in  its  interior ;  and  it  would  seem  that  we  may  regard  it  as 

1  It  has  been  recently  maintained  by  Keinhardt  that  the  Bird's  egg  is  really  homolo- 
gous with  the  Graafian  vesicle  of  the  Mammal,  and  its  entire  contents ;  the  "food-yelk" 
of  the  former  being  represented  in  the  latter  by  the  cellular  substance  surrounding  the 
zona  pellucida,  which  is  afterwards  developed  into  the  corpus  luteum. 


ACTION    OP   THE    FEMALE. 


959 


a  vesicle  of  evolution  for  the  ovum,  in  the  same  way  that  the  gland-cells  of  the 
testis  act  as  vesicles  of  evolution  for  the  spermatozoa.  The  development  of 
ovisacs  commences  at  a  very  early  period  of  life  ;  in  the  ovaries  of  some  animals, 
they  can  be  detected  almost  as  soon  as  these  organs  are  themselves  evolved ;  and 
in  all,  they  show  themselves  soon  after  birth.  In  Fig.  4  (Plate  I.),  is  repre- 
sented the  condition  of  the  Graafian  vesicles  in  various  stages  of  development, 
as  they  are  seen  imbedded  in  the  fibrous  stroma  of  the  ovarium,  in  a  thin  slice 
from  the  ovary  of  a  sow  three  weeks  old ;  by  which  time  the  germinal  vesicle, 
which  is  the  first  part  of  the  ovum  that  makes  its  appearance,  has  been  developed 
in  their  interior.  The  germinal  vesicle,  which  distinctly  shows  the  germinal 
spot,  is  surrounded  by  an  assemblage  of  granules,  which  is  the  first  indication 
of  a  yelk;  and  around  these  the  zona  pellucida  appears  to  be  subsequently 
developed.  The  Ovum  at  first  occupies  the  centre  of  the  Graafian  vesicle,  but 
it  subsequently  removes  to  its  periphery;  and,  when  the  contents  of  the  ovisac 
are  undergoing  maturation,  prior  to  their  escape,  the  ovum  is  always  found  on 
the  side  of  it  nearest  to  the  surface  of  the  ovary.  The  proper  ovisac,  whose 
wall  is  formed  of  a  non-vascular  membrane,  is  surrounded  by  a  vascular  layer, 
which  is  formed  by  a  condensation  of  the  ordinary  stroma  of  the  ovarium ;  it  is 
this,  which  is  reckoned  as  the  outer  layer  of  the  Graafian  vesicle. 

964.  A  continual  change  seems  to  be  taking  place  in  the  contents  of  the 
ovarium,  during  the  greater  part  of  life;  certain  of  the  ovisacs  or  Graafian 
vesicles,  and  their  contents,  successively  arriving  at  maturity,  whilst  others 
degenerate  and  die.     According  to  the  valuable  inquiries  of 

Dr.  Ritchie,1  it  appears  that,  even  during  the  period  of  child-  Fig.  243. 

hood,  there  is  a  continual  rupture  of  ovisacs  and  discharge  of 
ova,  at  the  surface  of  the  ovarium.  The  Ovaria  are  studded 
with  numerous  minute  copper-colored  maculae,  and  their 
surface  presents  delicate  vesicular  elevations,  which  are 
occasioned  by  the  most  matured  ovisacs;  the  dehiscence  of 
these  takes  place  by  minute  punctiform  openings  in  the 
peritoneal  coat,  and  no  cicatrix  is  left.  At  the  period  of 
puberty,  the  stroma  of  the  ovarium  is  crowded  with  ovisacs ; 
which  are  still  so  minute,  that  in  the  Ox  (according  to  Dr. 
Barry's  computation)  a  cubic  inch  would  contain  200  millions. 
of  them.  The  greatest  advance  is- seen  in  those  which  are 
situated  nearest  the  surface  of  the  Ovarium;  and  in  such 
the  Graafian  vesicle,  with  its  two  coats,  may  be  distinctly 
traced.  In  those  animals  whose  aptitude  for  conception  is 
periodical,  the  development  of  the  ova  to  such  a  degree  that 
they  become  prepared  for  fecundation  is  periodical  also. 
This  development  is  made  evident,  when  the  parts  are  ex- 
amined in  an  animal  which  is  "  in  heat/'  by  the  projection 
of  the  Graafian  vesicles  from  the  surface  (Fig.  243) ;  and  it 
consists  not  merely  in  an  increase  of  size,  but  in  certain  ovariumofthetfa&&#, 
internal  changes  presently  to  be  described.  at  the  period  of  Heat; 

965.  In  the  Human  female,  the  period  of  Puberty,  or  showing  various  stages 
of  commencing  aptitude  for  procreation,  is  usually  between   of  the  extrusi°n  of  ova. 
the   13th   and  16th   years;    it  is  generally  thought  to  be 

somewhat  earlier  in  warm  climates   than  in  cold,3  and  in  densely  populated 

1  "London  Medical  Gazette,"  1844. 

2  It  has  been  stated,  by  almost  all  physiological  writers,  that  women  (like  fruits)  reach 
maturity  and  that  menstruation  commences  much  earlier  in  hot  climates,  particularly 
between  the  tropics,  than  in  temperate  and  very  cold  countries ;  from  many  elaborate  and 
interesting  papers  which  have  been  published  within  a  few  years,  however,  especially  from 
those  of  Mr.  Roberton,  of  Manchester  (recently  collected  in  his  "Essays  on  Menstruation, 


060  OF   GENERATION. 

manufacturing  towns  than  in  thinly  peopled  agricultural  districts.  The 
mental  and  bodily  habits  of  the  individual  have  also  considerable  influence 
upon  the  time  of  its  occurrence ;  girls  brought  up  in  the  midst  of  luxury  or 
sensual  indulgence  undergoing  this  change  earlier  than  those  reared  in  hardi- 
hood and  self-denial.  The  changes  in  which  puberty  consists  are  for  the  most 
part  connected  with  the  reproductive  system.  The  external  and  internal  organs 
of  generation  undergo  a  considerable  increase  of  size;  the  mammary  glands 
enlarge;  and  a  deposition  of  fat  takes  place  in  the  mammae  and  on  the  pubes, 
as  well  as  over  the  whole  surface  of  the  body,  giving  to  the  person  that  round- 
ness and  fulness,  which  are  so  attractive  to  the  opposite  sex  at  the  period  of 
commencing  womanhood.  The  first  appearance  of  the  Catamenia  usually  occurs 
whilst  these  changes  are  in  progress,  and  is  a  decided  indication  of  the  arrival  of 
the  period  of  puberty;  but  it  is  not  unfrequently  delayed  much  longer;  and  its 
absence  is  by  no  means  to  be  regarded  as  a  proof  of  the  want  of  aptitude  for 
procreation,  since  many  women  have  borne  large  families,  without  having  ever 
menstruated.  The  Catamenial  discharge,  as  it  issues  from  the  uterus,  appears 
to  be  nearly  or  quite  identical  with  ordinary  blood;  but  in  its  passage  through 
the  vagina,  it  becomes  mixed  with  the  acid  mucus  exuded  from  its  walls,  which 
usually  deprives  it  of  the  power  of  coagulating.  If  the  discharge  should  be 
profuse,  however,  a  portion  of  its  fibrin  remains  unaffected,  and  clots  are  formed. 
In  cases  in  which,  by  the  death  of  women  at  this  period,  an  opportunity  has 
been  afforded  for  the  examination  of  the  lining  membrane  of  the  uterus  during 
menstruation,  it  is  found  to  be  unusually  turgid  with  blood,  the  veins  in  par- 
ticular being  much  distended,  and  opening  upon  the  internal  surface  by  capillary 
orifices,  to  which  valvules  are  occasionally  found  attached.1  Hence  it  is  scarcely 
correct  to  designate  the  menstrual  flux  as  a  "  secretion;"  although  there  is  reason 
to  think  that  it  may  carry  off,  besides  blood,  certain  matters  which  would  be 
appropriate  to  the  formation  of  a  decidual  membrane,  but  which,  if  not  so  em- 
ployed, become  excrementitious. — The  interval  which  usually  elapses  between 
the  successive  appearances  of  the  discharge  is  about  four  weeks;  and  the  dura- 
tion of  the  flow  is  from  three  to  six  days.  There  is  great  variety,  however,  in 
this  respect  among  the  inhabitants  in  different  climates,  and  among  individuals ; 
in  general,  the  appearance  is  more  frequent,  and  the  duration  of  the  flow  greater, 
among  the  residents  in  warm  countries,  and  among  individuals  of  luxurious 
habits  and  relaxed  frame,  than  among  the  inhabitants  of  colder  climes,  or  among 
individuals  inured  to  bodily  exertion.  The  first  appearance  of  the  discharge  is 
usually  preceded  and  accompanied  by  considerable  general  disturbance  of  the 
system ;  especially  pain  in  the  loins  and  a  sense  of  fatigue  in  the  lower  extremi- 
ties; and  its  periodical  return  is  usually  attended  with  the  same  symptoms, 
which  are  more  or  less  severe  in  different  individuals. 

966.  Much  discussion  has  taken  place  respecting  the  causes  and  purposes  of 
the  Menstrual  flow;  and  recent  inquiries  have  thrown  much  light  upon  them. 
The  state  of  the  female  generative  system,  during  its  continuance,  appears  to 
be  analogous  to  the  heat  of  the  lower  animals,  many  of  which  have  a  sero-san- 
guinolent  discharge  at  that  period.  There  is  good  reason  to  believe  that  in  the 

and  on  Practical  Midwifery,"  1851),  it  would  seem  that  the  natural  period  of  puberty  in 
temperate  climates  occurs  in  a  much  more  extended  range  of  ages,  and  is  much  more  equally 
distributed  through  that  range,  than  others  have  alleged ;  and  that  in  other  countries  the 
supposed  parallel  between  plants  and  fruits  does  not  hold  good.  The  fact  seems  to  be 
that  this,  like  other  periodic  phenomena  of  warm-blooded  animals,  is  but  little  influenced 
by  external  temperature,  simply  because  the  rate  of  growth  and  development,  of  which 
these  phenomena  are  the  exponents,  is  determined  by  the  temperature  of  the  body  itself, 
not  by  that  of  the  surrounding  medium.  Still  it  is  quite  possible  that  external  warmth 
may  have  a  slight  influence  in  determining  early  puberty ;  since,  as  already  shown,  it 
tends  to  maintain  a  somewhat  higher  degree  of  bodily  heat  ($  651). 
1  See  Whitehead  "On  Abortion  and  Sterility,"  pp.  13—37. 


ACTION   OF   THE   FEMALE.  961 

Human  female  the  sexual  feeling  becomes  stronger  at  that  epoch;  and  it  is 
quite  certain  that  there  is  a  greater  aptitude  for  Conception  immediately  before 
and  after  menstruation  than  there  is  at  any  intermediate  period.  Observations 
to  this  effect  were  made  by  Hippocrates,  and  were  confirmed  by  Boerhaave  and 
Haller;  indeed  coitus  immediately  after  menstruation  appears  to  have  been  fre- 
quently recommended  as  a  cure  for  sterility,  and  to  have  proved  successful.  It 
is  well  known  that,  among  many  of  the  lower  animals,  the  ova  are  entirely  ex- 
truded by  the  female,  before  the  spermatic  fluid  of  the  male  reaches  them ;  and 
that  even  in  Birds,  this  occasionally  takes  place.  This  question  has  been  made 
the  subject  of  special  inquiry  by  M.  Raciborski;  who  affirms  that  the  exceptions 
to  the  rule — that  conception  occurs  immediately  before  or  after,  or  during  men- 
struation— are  not  more  than  6  or  7  per  cent.  Indeed,  in  his  latest  work  on 
this  subject,1  he  gives  the  details  of  15  cases,  in  which  the  date  of  conception 
could  be  accurately  fixed,  and  the  time  of  the  last  appearance  of  the  catamenia 
was  also  known;  and  in  all  but  one  of  them,  the  correspondence  between  the 
two  periods  was  very  close.  Even  in  the  exceptional  case,  the  catamenia  made 
their  appearance  shortly  after  the  coitus;  which  took  place  at  about  the  middle 
of  the  interval  between  the  two  regular  periods.  When  conception  occurs 
immediately  before  the  menstrual  period,  the  catamenia  sometimes  appear,  and 
sometimes  are  absent;  if  they  appear,  their  duration  is  generally  less  than 
usual.  The  fact  that  conception  often  takes  place  immediately  before  the  last 
appearance  of  the  catamenia  (and  not  after  it,  as  commonly  imagined),  is  one 
well  known  to  practical  men. — Numerous  cases  have  been  collected  by  Mr. 
Girdwood,  Dr.  Robert  Lee,  MM.  Grendrin,  Negrier,  Raciborski,  and  others,  in 
which  the  menstrual  period  was  evidently  connected  with  the  maturation  and 
discharge  of  ova;  but  the  most  complete  observations  yet  made  upon  this  sub- 
ject are  those  of  Dr.  Ritchie  (loc.  cit.).  He  states  that  about  the  period  of 
puberty  a  marked  change  usually  takes  place  in  the  mode  in  which  the  ovisacs 
discharge  their  contents;  but  that  this  change  does  not  necessarily  occur  simul- 
taneously with  the  first  appeaiffcnce  of  the  catamenia;  as,  in  some  cases,  the 
conditions  which  obtain  in  the  period  before  puberty  are  extended  into  that  of 
menstruation.  The  ovaries  now  receive  a  much  larger  supply  of  blood ;  and 
the  ovisacs  show  a  great  increase  in  bulk  and  vascularity ;  so  that,  when  they 
appear  at  the  surface  of  the  ovary,  they  present  themselves  as  pisiform  turgid 
elevations;  and  the  discharge  of  their  contents  leaves  a  much  larger  cicatrix, 
and  is  accompanied  by  an  effusion  of  blood  into  their  cavity,  with  other  subse- 
quent changes,  to  be  presently  described.  It  would  appear,  however,  that 
although  such  a  discharge  takes  place  most  frequently  at  the  menstrual  period, 
yet  the  two  occurrences  are  not  necessarily  coexistent;  for  menstruation 
may  take  place  without  any  such  rupture;  whilst,  on  the  other  hand,  the 
maturation  and  discharge  of  mature  ova  may  occur  in  the  intervals  of  men- 
struation, and  even  at  periods  of  life  when  that  function  is  not  taking  place. 
Perhaps  the  most  correct  general  statement  on  the  subject  would  be  this :  that 
there  is  a  periodic  return  of  Ovarian  excitement,  which  tends  to  the  maturation 
and  extrusion  of  ovules,  though  it  may  not  always  reach  that  point ;  whilst 
there  is  also  a  periodic  turgescence  of  the  vessels  of  the  lining  membrane  of 
the  Uterus  which  tends  to  the  production  of  a  decidual  membrane ; — but  that 
these  two  periods,  though  usually  coincident,  are  not  necessarily  so;  and  that 
either  change  may  occur  without  the  concurrence  of  the  other. 

967.  The  duration  of  the  period  of  aptitude  for  procreation,  as  marked  by 
the  persistence  of  the  Catamenia,  is  more  limited  in  Women  than  in  Men, 
usually  terminating  at  about  the  45th  year;  it  is  sometimes  prolonged,  how- 
ever, for  ten  or  even  fifteen  years  further;  but  cases  are  rare  in  which  women 

1  "Sur  la  Ponte  des  Mammiferes,"  Paris,  1844. 

61 


962  OF   GENERATION. 

above  50  years  of  age  have  borne  children.  There  is  usually  no  menstrual  flow 
during  pregnancy  and  lactation ;  in  fact,  the  cessation  of  the  catamenia  is  gene- 
rally one  of  the  first  signs,  indicating  that  conception  has  taken  place.  But  it 
is  by  no  means  uncommon  for  them  to  appear  once  or  twice  subsequently  to 
conception ;  and  in  some  women,  there  is  a  regular  monthly  discharge,  though 
probably  not  of  the  usual  secretion,  through  the  whole  period.  Some  very 
anomalous  cases  are  on  record,  in  which  the  catamenia  never  appeared  at  any 
other  time  than  during  pregnancy;  and  were  then  regular.  The  absence  of  the 
catamenia  during  lactation  is  by  no  means  constant,  especially  if  the  period  be 
prolonged ;  when  the  menstrual  discharge  recurs,  it  may  be  considered  as  indi- 
cating an  aptitude  for  conception ;  and  it  is  well  known  that,  although  preg- 
nancy seldom  recurs  during  the  continuance  of  lactation,  the  rule  is  by  no  means 
invariable. 

968.  The  function  of  the  Female,  during  the  coitus,  is  essentially  passive. 
When  the  sexual  feeling  is  strongly  excited,  there  is  a  considerable  degree  of 
turgescence  in  the  erectile  tissue  surrounding  the  vagina,  and  composing  the 
greater  part  of  the  nymphas  and  the  clitoris;  and  there  is  an  increased  secretion 
from  various  glandular  follicles.1  But  these  changes  are  by  no  means  neces- 
sary for  effectual  coition  ;  since  it  is  a  fact  well  established,  that  fruitful  inter- 
course may  take  place,  when  the  female  is  in  a  state  of  narcotism,  of  somnambu- 
lism, or  even  of  profound  ordinary  sleep.  It  has  been  supposed  by  some,  that 
the  os  uteri  dilates,  by  a  kind  of  reflex  action,  to  receive  the  semen;  but  of 
this  there  is  no  evidence.  The  introduction  of  a  small  quantity  of  the  fluid 
just  within  the  vagina  appears  to  be  all  that  is  absolutely  necessary  for  con- 
ception ;  for  there  are  many  cases  on  record,  in  which  pregnancy  has  occurred, 
in  spite  of  the  closure  of  the  entrance  to  the  vagina  by  a  strong  membrane,  in 
which  but  a  very  small  aperture  existed.  That  the  spermatozoa  make  their 

1  The  glands  Qf  Duverney  have  been  very  accurately  described  by  Professor  Tiedemann 
(1840),  his  attention  having  been  directed  to  those  organs  by  the  late  Dr.  Fricke,  of  Ham- 
burg. These  glands  are  situated  at  either  side  of  the  entrance  of  the  vagina,  beneath  the 
integument  covering  the  inferior  part  of  the  vagina,  as  well  as  the  superficial  perineal 
fascia  and  the  constrictor  vaginae  muscle.  The  space  they  occupy  lies  between  the  lower 
end  of  the  vagina,  the  ascending  ramus  of  the  ischium,  the  crus  clitoridis,  and  the  erector 
clitoridis  muscle.  Superiorly  are  the  fibres  of  the  levator  ani  which  are  attached  to  the 
ischium,  and  behind  these  are  the  transversi-perinei  muscles.  They  are  surrounded  by 
very  loose  cellular  tissue.  They  are  rounded,  but  somewhat  elongated,  being  flat  and 
bean-shaped.  Their  long  diameter  is  from  5  to  10  lines;  their  transverse  diameter  2J  to 
4^  lines,  and  they  are  from  2 \  to  3  lines  thick.  Their  excretory  duct  is  at  the  anterior  edge 
of  the  superior  part  of  the  gland,  and  runs  beneath  the  constrictor  vaginas,  horizontally 
forwards  and  inwards,  to  the  inner  face  of  the  nympha,  opening  in  front  of  the  carunculae 
myrtiformes,  in  the  midst  of  a  number  of  small  mucous  follicles.  These  glands  were  first 
discovered  by  Duverney  in  the  cow,  about  the  middle  of  the  seventeenth  century.  Bar- 
tholinus  subsequently  found  them  in  the  human  female,  and  his  observations  were  con- 
firmed by  Duverney,  Morgagni,  Santorini,  Peyer,  &c.  Haller  denied  their  existence;  and 
their  presence  seems  to  have  been  forgotten  until  they  were  again  described  by  Mr.  Tay- 
lor ("Dublin  Journal,"  vol.  xiii.,  1838).  They  are  analogous  to  Cowper's  glands  in  the 
male,  according  to  Tiedemann,  and  like  them  are  sometimes  wanting,  and  differ  in  size. 
In  advanced  age  they  are  said  to  diminish  in  size,  and  even  to  disappear.  They  are  pre- 
sent in  the  females  of  all  animals,  where  Cowper's  glands  exist  in  the  males.  They 
secrete  a  thick,  tenacious,  grayish-white  fluid,  which  is  emitted  in  large  quantity  at  the 
termination  of  the  sexual  act,  most  likely  from  the  spasmodic  contraction  of  the  constric- 
tor vaginae  muscle,  under  which  they  lie.  Its  admixture  with  the  male  semen  has  been 
supposed  to  have  some  connection  with  impregnation  ;  but  no  proof  whatever  has  been 
given  that  any  such  admixture  is  necessary.  It  seems  not  improbable,  however,  that  it 
may  serve,  like  the  prostatic  fluid  of  the  male,  to  give  a  dilution  to  the  seminal  fluid  that 
is  favorable  to  its  action.  These  glands  were  probably  known  to  the  ancients,  and  it  is 
doubtless  their  secretion  which  Hippocrates  and  others  describe  as  the  female  semen. — 
These  glands  have  been  since  described  by  M.  Huguier,  in  the  "  Archives  d' Anatomic" 
(1847).  His  description  corresponds  in  every  respect  with  that  given  above. 


ACTION    OP   THE   FEMALE.  963 

way  towards  the  ovarium,  and  fecundate  the  ovum  either  before  it  entirely 
quits  the  ovisac  or  very  shortly  afterwards,  appears  to  be  the  general  rule  in 
regard  to  the  Mammalia;  and  the  question  naturally  arises — by  what  means 
do  they  arrive  there?  It  has  been  supposed  that  the  action  of  the  cilia  which 
line  the  Fallopian  tubes  might  account  for  their  transit ;  but  the  direction  of 
this  is  from  the  ovaria  towards  the  uterus,  and  would  therefore  be  opposed  to 
it.  A  peristaltic  action  of  the  Fallopian  tubes  themselves  may  generally  be 
noticed  in  animals  killed  soon  after  sexual  intercourse ;  and  in  those  which  have 
a  two-horned  membranous  uterus,  such  as  is  evidently  but  a  dilatation  of  the 
Fallopian  tube,  this  partakes  of  the  same  movement,  as  may  be  well  seen  in  the 
Rabbit;  but  this  peristaltic  action,  like  the  ciliary  movement,  is  from  instead 
of  towards  the  ovaries.  Among  the  tribes  whose  ova  are  fertilized  out  of  the 
body,  the  power  of  movement  inherent  in  the  spermatozoa  is  obviously  the 
means  by  which  they  are  brought  in  contact  with  the  ova ;  and  it  does  not 
seem  unreasonable  to  suppose  that  the  same  is  the  case  in  regard  to  the  higher 
classes,  and  that  the  transit  of  these  curious  particles,  from  the  vagina  towards 
the  ovaries,  is  effected  by  the  same  kind  of  action  as  that  which  causes  them  to 
traverse  the  field  of  the  microscope. — We  shall  now  consider  the  changes  in  the 
Ovum  and  its  appendages,  by  which  it  is  prepared  for  fecundation. 

969.  Up  to  the  period  when  the  Ovum  is  nearly  brought  to  maturity,  it  re- 
mains in  the  centre  of  the  ovisac  or  inner  layer  of  the  Graafian  follicle ;  and  it 
is  supported  in  its  place  by  the  "membrana  granulosa,"  which  is  continuous 
with  its  proligerous  disk.  The  movement  of  the  ovum  towards  the  surface, 
which  has  been  already  referred  to  as  a  part  of  the  changes  by  which  it  is  pre- 
pared for  fecundation,  appears  from  the  observations  of  Valentin  to  be  due  to 
the  following  cause.  In  the  immature  ovisac,  the  space  between  its  inner  layer 
and  the  ovum  is  for  the  most  part  filled  up  with  cells ;  these,  however,  gradu- 
ally dissolve  away,  especially  on  the  side  nearest  the  surface  of  the  ovary ; 
whilst  an  albuminous  fluid  is  effused  from  the  deeper  part  of  the  ovisac,  which 
pushes  the  residual  layer  (forming  the  discus  proligerus)  before  it,  and  thus 
carries  it  against  the  opposite  wall.  At  the  same  time,  there  is  a  gradual  thin- 
ning away  of  the  various  envelops  of  the  Graafian  follicle,  as  well  as  of  its  own 
walls,  in  the  situation  of  its  most  projecting  part;  and  thus  it  is  preparing  to 
give  way  at  that  point,  for  the  discharge  of  the  contained  ovum.  Before  rup- 
ture takes  place,  however,  the  ovisac  itself  undergoes  a  considerable  change. 
Its  walls  become  more  vascular  externally,  and  are  thickened  on  their  interior 
by  the  deposit  of  a  fleshy-looking  substance,  which,  in  many  of  the  lower  Mam- 
malia, is  of  a  reddish  color,  whilst  in  the  Human  female  it  is  rather  of  yellowish 
hue.  This  substance  is  at  first  entirely  composed  of  an  aggregation  of  cells 
(Fig.  244),  and  may,  in  fact,  be  considered  as  an  increased  development,  or 
hypertrophy,  of  the  "membrana  granulosa"  or  epithelial  lining  of  the  ovisac. 
In  domestic  quadrupeds,  this  growth,  which  sprouts  like  a  mass  of  granulations 
from  the  •  lining  of  the  ovisac,  is  often  so  abundant,  if  the  ovum  be  impregnat- 
ed, as  not  only  to  fill  the  cavity  of  the  -p.  244. 
ruptured  vesicle,  but  even  to  protrude 
from  the  orifice  on  the  surface  of  the 
ovary  ;  this  orifice,  however,  subsequent- 
ly closes ;  and  the  contained  growth  be- 
comes gradually  firmer,  its  color  chang- 
ing from  red  to  yellow.  In  the  Human 
female,  however,  the  new  formation  con- 
sequent upon  impregnation  is  less 
abundant ;  it  does  not  form  mammillary  _____ 

projections  from    the  interior  Of  the  Oyi-       Cells  forming  the  original  substance  of  the  Corpua 

sac,  but  lies  as  a  uniform  layer  upon  its  Luteum. 


964  OF   GENERATION. 

lining;  and  this  is  thrown  into  wrinkles  or  folds,  in  consequence  of  the  con- 
traction of  the  ovisac.  An  irregular  cavity  is  thus  at  first  left  in  the  interior 
of  the  ovisac,  after  the  discharge  of  the  ovum ;  but  this  gradually  diminishes, 
partly  in  consequence  of  the  increased  growth  of  the  yellow  substance,  and 
partly  owing  to  the  general  contraction  of  the  ovisac,  until  it  is  at  last  nearly 
obliterated  or  reduced  to  a  sort  of  stellate  cicatrix.  An  effusion  of  blood  fre- 

Fig.  245. 


Successive  stages  of  the  formation  of  the  Corpus  Luteum,  in  the  Graafian  follicle  of  the  Sow,  as  seen  in  ver- 
tical section :  at  a  is  shown  the  state  of  the  follicle  immediately  after  the  expulsion  of  the  ovum,  its  cavity 
being  filled  with  blood,  and  no  ostensible  increase  of  its  epithelial  lining  having  yet  taken  place;  at  b,  a  thick- 
ening of  this  lining  has  become  apparent :  at  c,  it  begins  to  present  folds  which  are  deepened  at  d,  and  the 
dot  of  blood  is  absorbed  pari  passu,  and  at  the  same  time  decolorized ;  a  continuance  of  the  same  process,  as 
shown  at  e,f,  g,  h,  forms  the  complete  Corpus  Luteum,  with  its  stellate  cicatrix. 

quently  takes  place  into  this  cavity,  in  the  Human  female,  at  the  time  of  the 
rupture  of  the  ovisac;  but  the  coagulum  which  is  left  takes  no  share  in  the 
formation  of  the  }7ellow  body.  It  generally  loses  its  coloring  matter,  and  ac- 
quires the  characters  of  a  fibrinous  clot;  and  this  may  either  form  a  sort  of 
membranous  sac,  lining  the  cavity,  or  it  may  become  a  solid  mass,  occupying 
the  centre  of  the  stellate  cicatrix. 

970.  The  cells  which  line  the  Graafian  follicle  undergo  a  great  increase 
of  size  at  the  time  of  the  discharge  of  the  ovule,  and  are  also  partially  meta- 
morphosed into  fibres,  especially  where  they  come  into  apposition  with  the 
enveloping  wall  of  the  follicle;  in  fact,  a  gradual  transition  may  be  traced 
between  the  cellular  substance  of  the  interior  of  the  follicle,  and  the  fibrous 
stroma  of  the  Ovarium  itself.  In  this  manner  is  formed  that  reddish-yellow 
granulation-like  substance,  friable  in  consistence,  and  very  vascular,  which  oc- 
cupies that  part  of  the  ovary  of  a  pregnant  female  whence  the  ovum  has  been 
discharged,  and  is  known  under  the  name  of  the  Corpus  Luteum.  Its  size  varies 
according  to  the  length  of  time  which  has  elapsed  since  conception.  At  first, 
it  is  usually  so  large  as  to  occasion  a  considerable  projection  on  the  surface  of 
the  ovary ;  its  form  is  oval,  or  resembles  that  of  a  bean.  When  cut  across,  its 
dimensions  are  usually  found  to  be  from  4  to  5-8 ths  of  an  inch  in  its  long 
diameter,  and  'from  3  to  4-8ths  in  its  short ;  and  it  thus  occupies  from  a  fourth 
to  a  half  of  the  whole  area  of  the  ovarium ;  but  these  dimensions  are  not  unfre- 
quently  exceeded.  The  centre^  of  this  substance  is  hollow ;  and  by  a  proper 
acquaintance  with  this  character,  the  true  Corpus  Luteum  maybe  distinguished 
from  substances  bearing  a  general  resemblance  to  it,  but  very  different  in  their 
character.  The  following  is  Dr.  Montgomery's  account  of  it :  "  Its  centre  ex- 
hibits either  a  cavity,  or  a  radiated  or  branching  white  line,  according  to  the 
period  at  which  the  examination  is  made  (Fig.  246).  If  within  the  first  three 
or  four  months  after  conception,  we  shall,  I  believe,  always  find  the  cavity  still 


ACTION   OF   THE   FEMALE. 


965 


existing,  and  of  such  a  size  as  to  be  capable  of  containing  a  grain  of  wheat  at 
least,  and  very  often  of  much  greater  dimensions ;  this  cavity  is  surrounded  by 
a  strong  white  cyst ;  and  as  gestation  proceeds,  the  opposite  parts  of  this  cyst 


Corpora  Lutea  of  different  periods :  B.  Corpus  luteum  of  about  the  sixth  week  after  impregnation,  showing 
its  plicated  form  at  that  period.  1.  Substance  of  the  ovary.  2.  Substance  of  the  corpus  luteum.  3.  A  gray- 
ish coagulum  in  its  cavity ;  after  Dr.  Patterson.  A.  Corpus  luteum,  two  days  after  delivery.  D.  In  the  twelfth 
week  after  delivery.  After  Dr.  Montgomery. 

approximate,  and  at  length  close  together,  by  which  the  cavity  is  completely 
obliterated,  and  in  its  place  there  remains  an  irregular  white  line,  whose  form 
is  best  expressed  by  calling  it  radiated  or  stelliform.  This  is  visible  as  long  as 
any  distinct  trace  of  the  corpus  luteum  remains."1  The  true  corpus  luteum  is 
further  distinguished  by  its  capability  of  being  injected  from  the  vessels  of  the 
ovary ;  which  is  not  the  case  with  tubercular  deposits  or  other  substances  which 
may  simulate  it.  After  delivery,  the  size  of  the  corpus  luteum  rapidly  dimi- 
nishes ;  and  in  a  few  months  it  ceases  to  be  recognizable  as  such.  The  cicatrix 
by  which  the  ovum  has  escaped  is  visible  for  some  time  longer ;  but  this,  too, 
according  to  the  careful  researches  of  Dr.  Montgomery,  cannot  be  distinguished 
at  a  subsequent  period.  Hence  there  is  no  correspondence  between  the  number 
of  corpora  lutea  found  in  the  ovaries  of  a  woman,  or  of  cicatrices  on  their  surface, 
and  the  number  of  children  she  may  have  borne.  The  number  of  corpora  lutea 
must  always  be  less,  when  there  have  been  many  conceptions,  in  consequence  of 
the  complete  disappearance  of  some  of  them ;  but  the  number  of  cicatrices  may 
be  greater;  for  several  causes,  such  as  the  escape  of  unimpregnated  ova,  or 
the  bursting  of  little  abscesses,  may  give  rise  to  such  appearances. 

971.  It  is  a  question  of  much  scientific  interest,  and  one  that  occasionally 
becomes  of  importance  in  Juridical  investigations,  what  extent  of  resemblance 
may  exist  between  the  condition  of  the  Ovisac  after  the  expulsion  of  an  ovum 
that  does  not  become  impregnated,  and  that  of  a  pregnant  female  in  which  a 
true  "  corpus  luteum"  is  present.  This  question  cannot  be  decided  by  observa- 
tions on  domesticated  quadrupeds;  since  it  appears  certain  that  in  them  there 
is  altogether  a  more  abundant  production  of  the  yellow  substance  than  in  the 
Human  female,  and  that  it  is  more  persistent  after  the  discharge  of  the  ovum  ; 
which  may  perhaps  be  accounted  for  by  the  greater  functional  activity  or  excite- 
ment of  the  ovarian  apparatus  in  an  animal  "  in  heat,"  than  usually  exists  in 
the  Human  female  at  the  menstrual  period.  There  is  reason,  moreover,  to 
believe  that  the  amount  of  this  may  vary  considerably  in  different  females,  and 
in  the  same  females  .  at  different  times.  The  general  fact  certainly  is,  that  a 
thin  layer  of  yellow  substance,  composed  chiefly  of  cells  and  of  fibres  originating 
in  the  metamorphosis  of  cells,  is  ordinarily  formed  on  the  lining  of  the  ovisac ; 
that  this  is  greatly  increased  in  thickness,  if  the  ovum  be  impregnated  ;  but  that 

1  "Signs  of  Pregnancy,"  p.  226. 


966  OF   GENERATION. 

if  it  be  not,  it  gradually  disappears ;  so  that,  from  this  difference  in  the  subse- 
quent changes  (which  may  be  probably  attributed  to  the  increased  determination 
of  blood  to  the  whole  Generative  apparatus  when  it  is  in  a  state  of  excessive 
functional  activity),  the  corpus  luteum  which  is  characteristic  of  the  pregnant 
state  is  usually  a  much  larger  and  more  highly  organized  body,  than  that  which 
is  commonly  found  in  the  ovary  of  the  unimpregnated  female.  But  it  is  also 
unquestionable  that  an  unusual  development  of  the  fibro-cellular  substance 
may  sometimes  take  place  without  impregnation ;  whilst,  on  the  other  hand,  the 
changes  which  usually  follow  impregnation  may  take  place  so  much  less  charac- 
teristically than  usual,  that  the  corpus  luteum,  even  at  an  early  period  of  preg- 
nancy, may  be  no  larger  than  that  which  is  often  found  where  pregnancy  has 
not  occurred.  These  variations,  which  seem  mainly  to  depend  upon  differences 
in  the  degree  of  vascular  excitement  of  the  ovaries,  accompanying  and  succeeding 
the  extrusion  of  ova,  render  it  impossible  to  draw  any  definite  line  of  demarca- 
tion, by  which  we  may  at  once  determine  what  are,  and  what  are  not,  the  results 
of  conception  ;  but  the  following  practical  rules,  deduced  from  a  consideration  of 
all  the  circumstances  yet  known,  may  be  laid  down  for  the  guidance  of  those 
who  find  it  desirable  to  have  some  standard  of  judgment :  "1.  A  Corpus  Lu- 
teum, in  its  earliest  stage  (that  is,  a  large  vesicle  filled  with  coagulated  blood, 
having  a  ruptured  orifice,  and  a  thin  layer  of  yellow  matter  in  its  walls),  affords 
no  proof  of  impregnation  having  taken  place. — 2.  From  the  presence  of  a 
Corpus  Luteum,  the  opening  of  which  is  closed,  and  the  cavity  reduced  or  ob- 
literated, only  a  stellate  cicatrix  remaining,  also  no  conclusion  as  to  pregnancy 
having  existed  or  fecundation  having  occurred  can  be  drawn,  if  the  corpus  luteum 
be  of  small  size,  not  containing  as  much  yellow  substance  as  would  form  a  mass 
the  size  of  a  small  pea. — 3.  A  similar  Corpus  Luteum  of  larger  size  than  a 
common  pea  would  be  strong  presumptive  evidence,  not  only  of  impregnation 
having  taken  place,  but  of  pregnancy  having  existed  during  several  weeks  at 
least ;  and  the  evidence  would  approximate  more  and  more  to  complete  proof, 
in  proportion  as  the  size  of  the  corpus  luteum  was  greater."1 

1  See  Dr.  Baly's  "  Supplement  to  Miiller'8  Physiology,"  p.  57;  where  a  comprehensive 
account  will  be  found  of  all  the  recent  researches  bearing  upon  this  question. — [The 
reader  is  also  referred  to  the  elaborate  prize  essay  of  Dr.  J.  C.  Dalton,  in  the  "  Transac- 
tions of  the  American  Medical  Association"  for  1851,  in  which  the  difference  between  the 
corpora  lutea  of  menstruation  and  pregnancy  is  clearly  made  out.  The  following  are 
some  of  the  characteristic  marks  by  which  the  two  may  be  recognized : — 

"  I.  The  corpus  luteum  of  pregnancy  arrives  more  slowly  at  its  maximum  of  development, 
and  afterward  remains  for  a  long  time  as  a  very  noticeable  tumor,  instead  of  undergoing 
a  process  of  rapid  atrophy. 

II.  It  retains  a  globular  or  only  slightly  flattened  form,  and  gives  to  the  touch  a  sense 
of  considerable  resistance  and  solidity. 

III.  Internally,  it  has  an  appearance  of  advanced  organization,  which  is  wanting  in  the 
corpus  luteum  of  menstruation. 

IV.  Its  convoluted  wall,  particularly,  attains  a  greater  development,  this  portion  mea- 
suring sometimes  so  much  as  three-sixteenths  to  one-fourth  of  an  inch  in  thickness,  while 
in  the  corpus  luteum  of  menstruation  it  never  exceeds  one-eighth,  and  is  almost  always 
less  than  that.     This  difference  in  the  thickness  of  the  convoluted  wall  is  one  of  the  most 
important  points  of  distinction.     It  will  be  much  more  striking  when  viewed  relatively  to 
the  size  of  the  central  coagulum. 

V.  The  color  is  not,  by  any  means,  so  decided  a  yellow,  but  a  more  dusky  and  indefinite 
hue. 

VI.  If  the  period  of  pregnancy  is  at  all  advanced,  it  is  not  found,  like  the  corpus  luteum 
of  menstruation,  in  company  with  unruptured  vesicles  in  active  process  of  development. 

The  histories  and  observations  detailed  by  Dr.  Dalton  will  serve  to  show  how  very  im- 
perfect are  some  of  the  marks  which  various  writers  have  heretofore  laid  down  as  dis- 
tinguishing 'true'  from  'false'  corpora  lutea.  Dr.  Montgomery*  gives  seven  charac- 
teristics by  which,  he  says,  the  'false,'  or  'virgin'  corpora  lutea  may  be  recognized. 


*  "  Signs  uud  Symptoms  of  Pregnancy,"  p.  245. 


ACTION   OF   THE   FEMALE.  967 

972.  It  cannot  now  be  doubted  that  the  maturation  and  discharge  of  ova 
from  the  Ovaries  is,  in  the  Human  female,  and  in  Mammalia  in  general,  an 
operation  quite  as  independent  of  conception,  and  even  of  sexual  intercourse,  as 
it  is  in  those  animals  in  which  the  ova  are  fertilized  out  of  the  body  -1  and  it  is 
no  longer  considered  essential,  therefore,  that  the  seminal  fluid  should  reach 
the  ovarium  in  order  to  effect  the  fertilization  of  the  ova,  since  this  end  may  be 
answered  by  the  contact  of  the  two  in  the  Fallopian  tubes,  or  even  in  the  Uterus 
itself.  From  the  experiments  of  Bischoff,  however,  it  appears  that  in  rabbits, 
bitches,  and  probably  in  most  other  Mammalia,  sexual  union  usually  takes  place 
previously  to  the  escape  of  the  ova  from  the  ovary,  and  that  sufficient  time 
often  elapses  for  the  seminal  fluid  to  reach  the  ovary  before  their  extrusion 
occurs ;  in  such  cases,  therefore,  it  would  seem  probable  that  fecundation  is 
effected  at  the  ovary  itself.  That  such  occasionally  happens  in  the  Human 
female  seems  to  be  unequivocally  proved  by  the  occurrence  of  tubal  or  even 
of  ovarian  foetation ;  the  ovum  having  received  the  fertilizing  influence  imme- 

'  I.  There  is  no  prominence  or  enlargement  of  the  ovary  over  them.' 

This  is  manifestly  incorrect,  for  the  corpora  lutea  of  menstruation  often  causes  a  notice- 
able protuberance  on  the  surface  of  the  ovary. 

'II.  The  external  cicatrix  is  almost  always  wanting.'  According  to  Dr.  Dalton's  ob- 
servations, an  external  cicatrix  is  always  present  in  the  corpus  luteum  of  menstruation, 
and,  in  fact,  must  necessarily  be  so,  since  these  bodies  result  from  the  rupture  of  a  vesicle, 
in  the  same  manner  with  the  corpora  lutea  of  pregnancy. 

4  III.  There  are  often  several  of  them  found  in  both  ovaries,'  &c.  This  is,  no  doubt, 
a  very  important  distinction,  since  we  never  find  more  than  one  corpus  luteum  of  preg- 
nancy at  a  time,  unless  in  cases  of  twins ;  and  then  the  two  corpora  lutea  are  evidently 
of  the  same  date,  and  have  the  same  aspect,  while  the  coexistent  corpora  lutea  of  men- 
struation are  usually  in  many  different  stages  of  retrogression. 

*  IV.  They  present  no  trace  whatever  of  vessels  in  their  substance,  of  which  they  are, 
in  fact,  entirely  destitute,  and,  of  course,  cannot  be  injected.' 

According  to  the  author's  observations,  the  distribution  of  vessels  in  the  two  different 
kinds  of  corpora  lutea  is  the  same.  In  both,  the  substance  of  the  convoluted  wall  itself 
is  non-vascular ;  and  the  vessels  exist  only  in  the  interstices  of  the  folds.  This  fact  is 
very  easily  demonstrated  in  a  corpus  luteum  of  menstruation  when  completely  developed, 
as  the  convolutions  are  here  pretty  easily  separated  from  each  other ;  but,  in  the  corpus 
luteum  of  pregnancy,  the  new  growth  from  the  internal  surface  of  the  vesicle  has  been  so 
abundant,  and  the  convolutions  are  consequently  pressed  so  firmly  together,  that  it  is  not 
always  easy  to  decide  whether  a  section  has  divided  the  substance  of  the  wall,  or  only  by 
accident  passed  between  two  convolutions ;  particularly  as  we  have  not  so  strong  a  con- 
trast in  color,  to  assist  us,  between  the  yellow  wall  and  red  vessels,  as  exists  in  the  corpus 
luteum  of  menstruation. 

'V.  Their  texture  is  sometimes  so  infirm  that  it  seems  to  be  merely  the  remains  of  a 
coagulum,'  &c.  This  is  frequently  a  good  distinguishing  mark. 

'VI.  In  figure  they  are  often  triangular,  or  square,  or  of  some  figure  bounded  by 
straight  lines.'  This  has  already  been  seen  to  be  an  appearance  frequently  presented  by 
the  corpus  luteum  of  menstruation,  at  an  advanced  period  of  atrophy. 

'  VII.  They  never  present  either  the  central  cavity,  or  the  radiated  or  stelliform  white 
line  which  results  from  its  closure.'  This  last  distinction  is  so  exceedingly  incorrect  that  it 
is  difficult  to  understand  how  it  could  have  been  laid  down  by  such  an  observer  as  Dr. 
Montgomery.  The  corpus  luteum  of  menstruation  always  presents  a  central  cavity,  i.  e., 
a  space  included  by  the  convoluted  wall,  which  space  is  filled  by  a  coagulum ;  and,  as  the 
whole  yellow  body  becomes  atrophied,  the  coagulum  is  transformed  into  a  radiated^or 
stelliform  cicatrix,  more  or  less  colored  with  blood,  according  to  the  rapidity  with  which 
the  absorption  of  the  hsematin  has  proceeded. 

There  can  be  no  doubt,  therefore,  of  the  existence  of  certain  distinct  and  reliable  marks 
by  which  the  corpus  luteum  may  be  recognized  as  a  sign  of  pregnancy,  and  distinguished 
from  all  other  appearances,  either  morbid  or  physiological,  to  be  met  with  in  the  ovary." — 
ED.] 

'  Two  cases  in  which  Ovules,  or  their  remains,  were  discovered  in  the  Fallopian  tubes 
of  Women  who  had  died  during  the  Menstrual  period,  under  circumstances  which  entirely 
precluded  the  idea  of  previous  sexual  intercourse,  have  been  lately  recorded  by  Dr.  Letheby 
("Phil.  Trans.,"  1852,  p.  57). 


968  OF   GENERATION. 

diately  upon  quitting  the  ovisac,  or  even  before  it  has  entirely  extricated  itself 
from  the  ovary,  and  having  been  in  some  way  checked  in  its  transit  towards 
the  uterus,  so  that  its  development  has  taken  place  in  the  spot  at  which  it  has 
been  arrested.  It  is  affirmed  by  Bischoff  that  by  the  time  the  ovum  reaches  the 
uterus,  or  even  the  lower  end  of  the  Fallopian  tube,  its  capacity  for  impregna- 
tion is  lost ;  but  this  assertion  chiefly  rests  on  the  cessation  of  sexual  desire, 
observed  in  those  animals  in  which,  after  death,  it  was  found  that  the  ova  had 
passed  into  the  uterus,  or  had  arrived  at  the  lower  part  of  the  Fallopian  tube. 
There  is  every  reason  to  believe  that  this  is  not  the  case  in  the  Human  female ; 
for,  although  the  sexual  desire  may  be  the  strongest  about  the  period  of  the 
maturation  and  escape  of  the  ova,  yet  it  is  by  no  means  wanting  at  other  times  ; 
and  the  occasional  occurrence  of  cases  in  which  impregnation  has  taken  place 
from  a  single  coitus  in  the  middle  of  the  interval  between  the  menstrual  periods, 
shows  either  that  the  ovum  may  retain  its  capacity  for  impregnation  for  some 
time  after  its  escape  from  the  ovary,  or  that  its  maturation  and  extrusion  are 
not  by  any  means  invariably  coincident  with  the  menstrual  period.1 — The  ova, 
when  set  free  from  the  ovaries  by  the  rupture  of  the  ovisacs  and  the  giving  way 
of  their  several  envelops,  are  received  by  the  fimbriated  extremities  of  the  Fal- 
lopian tubes,  which,  during  the  period  of  sexual  excitement,  appear  to  be  closely 
applied  to  the  surface  of  the  ovaries.  Their  conveyance  along  the  Fallopian 
tubes  is  probably  due  in  part  to  their  peristaltic  movement,  and  in  part  to  the 
action  of  the  cilia  which  clothe  their  internal  surface. 

973.  The  object  of  the  changes  which  have  been  already  described  is  to  bring 
the  Ovum  within  reach  of  the  fecundating  influence,  and  to  convey  it  into  the 
uterus  after  it  has  been  fertilized  :  we  have  now  to  consider  the  changes  in  the 
Ovum  itself,  which  take  place  during  the  same  epoch.  At  about  the  same 
period  that  the  ovum  moves  towards  the  periphery  of  the  Graafian  follicle,  the 
germinal  vesicle  moves  towards  the  periphery  of  the  yelk ;  and  it  always  takes 
up  its  position  at  the  precise  point  of  the  zona  pellucida  which  is  nearest  the 
ovisac,  and  which  is  closest,  therefore,  to  the  surface  of  the  ovary.  Moreover, 
the  germinal  spot  is  always  on  that  part  of  the  germinal  vesicle  which  is  in 
closest  contact  with  the  zona  pellucida.  Thus,  the  germinal  spot  is  very  near 
the  exterior  of  the  ovary ;  but  is  separated  from  it  by  the  peritoneal  coat  of  the 
latter,  by  a  thin  layer  of  its  stroma  forming  the  external  layer  of  the  Graafian 
follicle,  by  the  ovisac  forming  its  internal  membrane,  and  by  the  zona  pellucida. 
As  soon  as  these  give  way,  there  is  nothing  to  prevent  the  spermatozoa  from 
coming  into  direct  contact  with  the  ovum,  even  before  it  quits  the  ovisac. 
That  such  contact  is  an  essential  condition  of  fecundation,  there  is  every  reason 
to  believe ;  although,  as  to  the  precise  manner  in  which  it  operates,  we  are  at 
present  in  the  dark.  There  can  be  no  doubt  that  it  is  in  the  contact  of  the 
spermatozoa  with  the  ovum,  and  in  the  changes  which  occur  as  the  immediate 
consequence  of  that  contact,  that  the  act  of  Fecundation  essentially  consists. 
We  have  already  seen  that  the  Spermatozoa  constitute  the  essential  part  of  the 
Seminal  fluid  (§  959) ;  and  although  it  has  been  ascertained  by  Mr.  Newport, 
that  the  spermatic  fluid  as  secreted  by  the  testes  is  inferior  in  fertilizing  power 

1  See  a  case  of  this  kind  recorded  by  Dr.  Oldham  in  the  "Medical  Gazette,"  July  13, 
1849. — Instances  are  certainly  not  unfrequent  in  which  conception  has  taken  place  five  or 
six  days  after  the  conclusion  of  the  menstrual  period ;  the  Author  has  himself  known  one 
in  which  this  occurred,  after  the  menstrual  flow  itself  had  persisted  for  a  week.  It  has 
been  urged  that  the  known  fertility  of  the  Jewish  females,  who  abstain  from  sexual  inter- 
course for  eight  days,  or  even  thirteen  days,  after  the  termination  of  the  catamenia,  is 
opposed  to  the  idea  that  the  menstrual  period  is  that  of  "heat";  but  there  is  reason  to 
believe  that  this  is  to  be  accounted  for  in  another  way — namely,  by  the  usual  occurrence 
of  conception  from  intercourse  immediately  before  the  access  of  the  catamenia.  (See  Mr. 
Girdwood,  in  the  "Lancet,"  Dec.  14,  1844.) 


ACTION   OF   THE   FEMALE. 

to  that  which  has  been  mingled  with  the  prostatic  fluid,  yet  it  seems  that  this 
inferiority  simply  results  from  its  state  of  too  great  concentration,  and  not  from 
any  endowments  peculiar  to  the  prostatic  fluid,  since  dilution  with  other  fluids 
answers  the  same  purpose.  Mr.  Newport's  most  recent  observations  upon  the 
process  of  impregnation  in  the  Frog  (which  the  Author,  through  the  kindness 
of  Mr.  N.,  has  had  the  opportunity  of  verifying)  show  that  the  spermatozoa 
become  imbedded  in  the  gelatinous  envelop  of  the  ovum,  within  a  few  seconds 
after  they  come  into  contact  with  it,  and  that  they  are  thus  brought  into  close 
approximation  with  (if  they  do  not  absolutely  pass  through)  the  vitelline  mem- 
brane ;  in  this  situation  they  probably  undergo  a  gradual  diffluence ;  and  thus 
the  product  of  the  "  sperm-cell"  may  be  absorbed  into  the  "  germ-cell,"  and 
may  intermingle  with  its  contents,  just  as  in  the  fecundation  of  the  ovule  of 
Flowering-plants ;  the  Spermatozoon  being  nothing  else  than  an  embodiment  of 
the  fertilizing  material  developed  within  the  sperm-cell,  which  is  endowed  with 
a  temporary  power  of  movement  in  order  that  it  may  find  its  way  to  the  Ovum. 
It  has  been  remarked  by  Mr.  Newport  that  Spermatozoa  whose  spontaneous 
moft'foVy  has  ceased,  no  longer  possesses  the  fecundating  power;  and  this  fact 
concurs  with  other  phenomena  to  indicate  that  it  is  not  only  a  certain  material, 
but  a  vital  force  of  which  that  material  is  (so  to  speak)  the  vehicle,  which  is 
required  to  effect  this  most  important  operation. 

974.  The  precise  share  which  the  Germinal  Vesicle  and  Germinal  Spot  per- 
form in  the  changes  which  take  place  in  the  ovum  about  the  period  of  fecunda- 
tion, has  not  yet  been  satisfactorily  determined.     According  to  Dr.  Barry,  the 
germinal  vesicle  becomes  filled  with  a  new  development  of  cells,  which  sprout, 
as  it  were,  from  its  nucleus  (the  germinal  spot)  :  and  after  fecundation  a  pair  of 
cells  is  seen  in  the  space  previously  occupied  by  the  pellucid  centre  of  the  nucleus 
which  is  developed  at  the  expense  of  the  rest,  and  is  the  true  foundation  of  the 
embryonic  structure.     This  view  is  to  a  certain  extent  confirmed  by  the  observa- 
tions of  Wagner  on  the  ova  both  of  Frogs  and  Mammalia,  and  by  those  of  Vogt 
on  those  of  the  Rana  obstetricans  :  both  of  which  lead  to  the  belief  that  such  a 
process  of  cell-formation  does  take  place  within  the  germinal  vesicle,  but  that, 
instead  of  the  further  development  being  carried  on  within  the  germinal  vesicle, 
as  maintained  by  Dr.  Barry,  this  ruptures  and  sets  free  the  cells  that  had  been 
developed  in  its  interior,  which  are  now  dispersed  through  the  yelk,  whose  ulte- 
rior changes  take  place  under  their  influence.     Mr.  Newport's  view  is  nearly 
the  same  as  this;  and  he  states  that,  in  the  Frog,  this  dissolution  of  the  germinal 
vesicle  and  diffusion  of  its  contents  take  place  as  a  preparation  for  fecundation, 
and  not  in  consequence  of  it.1     That  the  germinal  vesicle  is  no  longer  to  be  seen 
when  the  metamorphoses  of  the  yelk  have  commenced,  is  now  universally  ad- 
mitted; but  with  regard  to  the  antecedent  process  just  described,  there  is  still  a 
want  of  accordance  amongst  Embryologists,  its  existence  being  altogether  denied 
by  Bischoff,  who  maintains  that  the  germinal  vesicle    simply  dissolves  away 
shortly  after  coition,  as  had  been  supposed  by  Dr.  Barry's  predecessors.     The 
Author  is  strongly  inclined  to  believe,  however,  from  his  own  observations,  as 
well  as  from  a  priori  considerations,  based  on  the  history  of  Vegetable  fertiliza- 
tion, that  there  is  a  development  of  cells  within  the  germinal  vesicle,  at  the  time 
of  its  maturation  ;  and  that  it  is  by  the  influence  of  the  spermatic  fluid  upon  one 
of  these  cells,  after  it  has  been  set  free  in  the  midst  of  the  yelk  by  the  rupture 
or  diffluence  of  the  germinal  vesicle,  that  the  first  cell  of  the  embryonic  fabric 
is  generated. 

975.  Whatever  be  the  precise  nature  and  history  of  the  Fecundating  process, 
there  can  be  no  doubt  that  the  properties  of  the  germ  depend  upon  conditions, 
both  material  and  dynamical,  supplied  by  both  parents.     This  is  most  obviously 

1  "Philosophical  Transactions,"  1851,  p.  178. 


970  OF   GENERATION. 

shown  by  the  fusion  of  the  characters  of  the  parents,  which  is  exhibited  by  hy- 
brids between  distinct  species  or  strongly-marked  varieties  among  the  lower 
animals,  such  as  the  Horse  and  Ass,  the  Lion  and  Tiger,  or  the  various  breeds 
of  Dogs;  or  in  the  offspring  of  parents  belonging  to  two  strongly-contrasted  Races 
of  Men,  such  as  the  European,  on  the  one  hand,  and  the  Negro  or  American 
Indian  on  the  other.  But  it  is  rare  to  meet  with  instances,  even  when  the  dif- 
ferences between  the  parents  are  far  less  strongly  marked,  in  which  some  dis- 
tinctive traits  of  both  may  not  be  readily  traced;  these  traits  showing  themselves 
in  peculiarities  of  manner  and  gesture,  in  tendencies*  of  thought  or  feeling,  in 
proneness  to  particular  constitutional  disorders,  &c.,  even  where  there  is  no  per- 
sonal resemblance,  and  where  there  has  been  no  possibility  that  these  peculiari- 
ties should  have  been  gained  by  imitation.  And  it  is  well  known,  too,  that  such 
peculiarities  will  often  reappear  in  a  subsequent  generation,  after  being  appa- 
rently extinct;  as  if  the  agency  which  produced  them  had  been  overpowered  for 
a  time  by  some  stronger  influence,  but  had  subsequently  been  left  free  to  operate. 
This  phenomenon  is  known  as  atavism. — The  influence  of  particular  perversions 
of  the  regular  nutritive  operations,  brought  about  by  causes  to  which  the  parents 
have  been  exposed,  is  often  manifested  in  the  offspring ;  thus  we  find  gout,  scro- 
fula, syphilis,  &c.,  hereditarily  transmitted;  and  the  children  of  habitual  drunk- 
ards are  distinguished  by  their  tendency  to  Idiocy  and  Insanity.1 — There  seems 
good  reason  to  believe,  moreover,  that  the  attributes  of  the  germ  are  in  great 
degree  dependent,  not  merely  upon  the  habitual  conditions  of  the  parents  which 
have  furnished  its  original  components,  but  even  upon  the  condition  in  which 
those  parents  may  be  at  the  time  of  sexual  congress.  Of  this  we  have  a  remark- 
able proof  in  the  phenomenon  well  known  to  breeders  of  animals,  that  a  strong 
mental  impression  made  upon  the  female  by  a  particular  male  will  give  the  off- 
spring a  resemblance  to  him  even  though  she  has  had  no  sexual  intercourse  with 
him ;  a  circumstance  for  which  there  is  no  difficulty  in  accounting,  on  the  hypo- 
thesis already  put  forth  regarding  the  dynamical  relation  of  Mental  states  to  the 
Organic  processes  (§  945).  And  there  is  no  improbability,  therefore,  in  the  idea 
that  the  offspring  of  parents  ordinarily  healthy  and  temperate,  but  begotten  in 
a  fit  of  intoxication  on  both  sides,  would  be  likely  to  suffer  permanently  from  the 
abrogation  of  the  reason,  which  they  have  temporarily  brought  upon  themselves.3 
There  is  another  class  of  facts  which  seems  referable  to  the  same  category,  that, 
namely,  which  exhibits  the  influence  of  a  male  parent  upon  the  subsequent 
offspring  of  a  different  parentage ;  as  in  the  well-known  case  of  the  transmission 
of  the  Quagga-marks  to  a  succession  of  colts  both  whose  parents  were  of  the 
species  Horse,  the  mare  having  been  once  impregnated  by  the  Quagga  male  ;3 
and  in  the  not  unfrequent  occurrence  of  a  similar  phenomenon  in  the  Human 
species,  as  when  a  widow  who  marries  a  second  time  bears  children  strongly  re- 
sembling her  first  husband.  Some  of  these  cases  appear  referable  to  the  strong 
mental  impression  left  by  the  first  male  parent  upon  the  female ;  but  there  are 
others  which  seem  to  render  it  more  likely  that  the  blood  of  the  female  has 
imbibed  from  that  of  the  fo3tus,  through  the  placental  circulation,  some  of  the 
attributes  which  the  latter  has  derived  from  its  male  parent ;  and  that  the  female 
may  communicate  these,  with  those  proper  to  herself,  to  the  subsequent  offspring 
of  a  different  male  parentage.4 — On  the  whole,  then,  we  seem  entitled  to  con- 

1  See  the  Author's  "Prize  Essay  on  Alcoholic  Liquors,"  $  36,  Am.  Ed.,  and  Dr.  Howe's 
"  Report  on  Idiocy  in  Massachusetts,"  in  the  Am.  Journ.  oi'Mecl.  Sci.,  April,  1849. 

2  See  a  case  of  this  kind  related  by  Mr.  G.  Combe,  in  the  "Phrenological  Journal," 
vol.  viii.  p.  471.' 

3  "  Philosophical  Transactions,"  1821. 

4  See  an  interesting  discussion  of  this  question,  by  Dr.  Alex.  Harvey,  in  the  "Edinb. 
Monthly  Journ.,"  Oct.   1849,  and  Oct.  and  Nov.  1850;  and  in  his  pamphlet  "On  a  Re- 
markable Effect  of  Cross-breeding,"  Edinb.  1851. 


ACTION   OF   THE   FEMALE.  971 

elude  that  the  attributes  of  the  embryo  will  be  influenced  in  a  most  important 
degree  by  the  entire  condition  (as  relates  both  to  the  organic  and  the  psychical 
life)  of  both  parents  at  the  time  of  the  sexual  congress ;  and  it  is  probably  on 
account  of  the  perpetual  changes  taking  place  in  the  bodily  and  mental  state  of 
each  individual  (his  condition  at  any  one  time  being  the  general  resultant  of  all 
those  changes),  that  we  almost  constantly  witness  marked  differences  between 
children  born  at  successive  intervals,  however  strong  may  be  the  "  family  like- 
ness" among  them,  whilst  the  resemblance  between  twins  is  almost  invariably 
much  closer.1 

976.  Having  thus  noticed  the  principal  points  of  the  history  of  the  develop- 
ment and  impregnation  of  the  ovum,  we  shall  proceed  to  consider  the  provisions 
made  for  the  Nutrition  of  the  Embryo,  through  the  generative  apparatus  of 
the  female,  up  to  the  time  of  parturition ;  deferring  the  history  of  the  develop- 
ment of  the  ovum  for  that  separate  consideration  which  the  importance  of  that 
subject  demands. — About  the  time  that  the  ovum  is  leaving  the  ovary,  the  cells 
of  the  proligerous  disk  which  immediately  surrounds  the  zona  pellucida  become 
club-shaped  (Fig.  247) ;  their  small  ends  being  applied  to  the  surface  of  the 
ovum,  so  as  to  give  it  somewhat  of  a  stellate  appearance.  According  to  Bis- 
choff,  these  cells  entirely  disappear  from  the  ovum  of  the  rabbit,  as  soon  as  it 
has  entered  the  Fallopian  tube;  whilst  in  the  bitch  they  become  round,  and 
continue  to  invest  the  ovum  in  this  form  throughout  its  whole  transit  to  the 
uterus.  During  its  passage,  the  ovum  acquires  a  sort  of  gelatinous  envelop, 
which  is  inclosed  in  a  membrane  of  fibrous  texture,  termed  the  Chorion.  This 
envelop  is  probably  of  an  albuminous  nature  in  reality,  corresponding  with 
the  white  of  the  Bird's  egg :  whilst  the  fibrous  texture  of  the  chorion  seems  to  be 

Fig.  247. 


• .  An  ovarian  ovum  from  a  Bitch  in  heat,  exhibiting  the  elongated  form  and  stellate  arrangement  of  the 
cells  of  the  discus  proligerus  or  membrana  granulosa  around  the  zona  pellucida.  B.  The  same  ovum  after 
the  removal  of  most  of  the  club-shaped  cells. 

produced,  like  the  membranous  basis  of  the  eggshell  of  the  bird,3  by  the  exuda- 
tion of  fibrin  from  the  lining  membrane  of  the  Fallopian  tube  or  oviduct.  The 
outer  layer  of  this  envelop,  in  the  egg  of  the  bird,  is  consolidated  by  the  de- 
position of  particles  of  carbonate  of  lime  in  its  areolse ;  and  none  of  it  under- 
goes any  higher  organization.  The  Chorion  of  the  Mammal,  on  the  other 
hand,  subsequently  undergoes  changes  of  a  much  higher  order ;  which  adapt  it 
for  participating,  to  a  most  important  degree,  in  the  nutrition  of  the  included 
embryo.  The  first  of  these  changes  consists  in  the  extension  of  the  surface  of 

1  This  strong  resemblance,  it  is  true,  is  occasionally  deficient;  but  this  may  perhaps  be 
fairly  attributed  to  the  circumstance  of  the  twins  being  the  offspring  of  different  concep- 
tions, which  is  undoubtedly  sometimes  the  case,  as  is  shown  by  the  long  interval  that 
elapses  between  their  births  ($  990). 

2  'Trine,  of  Phys.,  Gen.  and  Comp.,"  g  160,  Am.  Ed. 


972  OF   GENERATION. 

the  membrane  into  a  number  of  villous  prolongations,  at  first  composed  entirely 
of  cells,  which  give  it  a  spongy  or  shaggy  appearance  (Plate  I.  Fig.  10).  These 
serve  as  absorbing  radicles,  and  form  the  channel  through  which  the  embryo  is 
nourished  by  the  fluids  of  the  parent,  until  a  more  perfect  communication  is 
formed,  in  the  manner  to  be  presently  explained. 

977.  We  have  now  to  speak  of  the  changes  in  the  Uterus  which  take  place 
in  consequence  of  Conception,  and  which  prepare  it  to  receive  the  ovum.  Of 
these  the  most  important  is  the  formation  of  the  Membrana  Decidua,  so  called 
from  its  being  cast  off  at  each  parturition.  This  membrane  has  been  usually  sup- 
posed to  be  a  new  formation  ;  and  has  been  described  as  originating  in  coagulable 
lymph  thrown  out  on  the  inner  surface  of  the  uterus,  into  which  vessels  are  pro- 
longed from  the  subjacent  surface.  It  appears,  however,  from  the  researches  of  Dr. 
Sharpey  and  Prof.  Weber,1  that  this  is  not  the  true  account  of  it ;  and  that  the 
Decidua  vera  is  really  composed  of  the  inner  portion  of  the  Mucous  membrane 
itself,  which  undergoes  a  considerable  change  in  its  character.  The  Mucous  mem- 
brane of  the  uterus  possesses  on  its  free  surface  a  tubular  structure  (Figs.  248, 
249) ;  not  very  unlike  that  which  has  been  described  as  existing  in  the  lining 
membrane  of  the  stomach  (§  440).  This  tubular  portion  becomes  thickened 
and  increased  in  vascularity,  within  a  short  time  after  conception ;  and  when 
the  inner  surface  of  a  newly-impregnated  uterus  is  examined  with  a  low  mag- 
nifying power,  the  orifices  of  its  tubes  are  very  distinctly  seen,  being  lined  with 
a  white  epithelium.  The  bloodvessels  form  a  very  minute  network,  which  ex- 
tends in  loops  from  the  subjacent  portion  of  the  membrane.  According  to  the 
observations  of  Prof.  Groodsir,3  the  interfollicular  spaces  also  are  crowded  with 
nucleated  particles ;  and  it  is  to  the  development  of  this  interfollicular  sub- 
stance, as  well  as  to  the  enlargement  of  the  follicles  themselves,  and  the  copious 
development  of  epithelial  cells  in  their  interior,  that  the  mucous  membrane  in 
this  condition  owes  its  increased  thickness.  This  increased  development  appears 
to  have  reference  in  part  to  the  temporary  nutrition  of  the  ovum,  and  in  part 
to  the  further  evolution  of  the  decidual  substance  itself  in  the  formation  of  the 

Fig.  248. 


Section  of  the  lining  membrane  of  a  Human  Uterus  at  the  period  of  commencing  pregnancy,  showing  the 
arrangement  and  other  peculiarities  of  the  glands  d,  d,  d,  with  their  orifices  a,  a,  a,  on  the  internal  surface 
of  the  organ.  Twice  the  natural  size.  After  E.  H.  Weber. 

Placenta.  The  cavity  of  the  uterus  shortly  becomes  filled  with  a  fluid,  evidently 
poured  out  from  the  follicles  in  its  walls,  and  containing  a  large  number  of 
nucleated  cells ;  and  in  this  the  villi  of  the  chorion  are  imbedded,  obviously 
for  the  purpose  of  deriving  from  it  the  materials  required  for  the  development 
of  the  embryonic  structures.  These  villi  are  easily  traced  in  the  bitch  (as  Dr. 
Sharpey  first  pointed  out)  into  the  mouths  of  the  uterine  glandulae,  some  of 
which  are  composite  in  their  structure,  a  single  outlet  being  common  to  a  num- 
ber of  follicles;  but  they  have  not  yet  been  so  traced  in  the  Human  subject. 

1  Muller's  "Elements  of  Physiology,"  pp.  1574-1580. 

2  "Anatomical  and  Physiological  Observations,"  chap.  ix. 


ACTION   OF   THE   FEMALE. 
Fig.  249.  Fig.  250. 


973 


Two  thin  segments  of  Human  Dacidua, 
after  recent  impregnation,  viewed  on  a 
dark  ground ;  they  show  the  openings 
on  the  surface  of  the  membrane.  A  is 
magnified  six  diameters  and  B  twelve 
diameters.  At  1,  the  lining  of  epithelium 
is  seen  within  the  orifices ;  at  2,  it  has 
escaped.  From  Dr.  Sharpey  (xxxii.). 


A  portion  of  Fig.  248  more  enlarged,  show- 
ing the  convoluted  extremities  of  the  tubular 
glandulae. 

978.  The  Deciduous  membrane  is  found  at  a  later  period  to  consist  of  two 
layers ;  the  Decidua  vera  lining  the  uterus,  and  the  Decidua  reflexa  covering 
the  exterior  of  the  ovum.  Regarding  the  origin  of  this  second  layer,  there  has 
been  a  good  deal  of  difference  of  opinion.  The  doctrine  first  propounded  by 
Dr.  W.  Hunter,  which  is  indicated  by  the  name  which  he  bestowed  upon  the 
membrane,  was  that  the  decidua  reflexa  is  a  portion  of  the  true  decidua,  which 
has  been  pushed  before  the  ovum  at  its  entrance  into  the  uterus;  it  being  sup- 
posed that  the  true  decidua  forms  a  completely  closed  sac  (like  that  of  a  serous 
membrane),  against  the  outside  of  which  the  ovum  is  applied,  so  that  it  comes 
to  be  invested  by  a  double  layer  of  it,  as  the  heart  is  by  the  pericardium,  or 
the  lungs  by  the  pleura.  But  this  view  is  negatived  by  a  number  of  consider- 
ations. For,  in  the  first  place,  the  original  decidua  does  not  form  the  closed 
sac  which  this  supposition  involves,  but  extends  (like  the  mucous  membrane 
of  which  it  is  a  metamorphosed  form)  into  the  Fallopian  tubes ;  and  the  ovum, 
at  its  entrance  into  the  uterus,  really  lies  upon  its  internal  surface.  But, 
again,  the  texture  of  the  two  layers  is 
very  different;  for,  as  was  first  pointed 
out  by  Prof.  Goodsir  (loc.  cit.),  the 
decidua  reflexa  is  almost  entirely  com- 
posed of  cells,  exhibiting  few  or  none 
of  the  orifices  of  the  glandular  follicles 
which  are  characteristic  of  the  decidua 
vera,  except  near  the  part  where  the 
two  layers  are  continuous.  According 
to  the  observations  of  M.  Coste,  how- 
ever, there  is  a  considerable  resem- 
blance between  the  two  layers  at  an 


Fig.  251. 


First  stage  of  the  formation  of  the  Decidua  reflexa 
around  the  ovum. 

early   period:    and   he  considers   the 

following  to  be  the  mode  in  which  the  second  investment  is  formed :  When 


974  OF   GENERATION. 

the  ovum  enters  the  uterus,  it  becomes  partially  imbedded  in  the  substance  of 
the  decidua,  which  is  as  yet  quite  soft  (Fig.  251) ;  and  this,  receiving  an  in- 
creased nutrition  at  the  part  with  which  the  ovum  comes  into  contact,  grows  up 

around  it,  very  much  after  the  man- 
Fig.  252.  ner  in  which  the  fleshy  granulations 
grow  up  around  the  pea  imbedded  in 
a  caustic  issue.  This  extension  of 
the  decidual  substance  continues  (Fig. 
252),  until  i*  nas  completely  enve- 
loped the  ovum;  and  it  is  thus,  ac- 
cording to  him,  that  the  decidua  re- 
flexa  is  formed,  in  continuity  with 
the  decidua  vera.1  As  the  ovum 
increases  in  size,  the  cavity  between 

'•iSBH^^  the  decidua  vera  and  the  decidua  re- 

flexa  gradually  diminishes;  and  by 

More  advanced  stage  of  the  same.  the  end    of  the  third  month  the   two 

layers  come   into   contact,  and   are 
henceforth  scarcely  or  not  at  all  distinguishable. 

979.  The  surface  of  the  Ovum,  thus  surrounded  by  the  double  layer  of  the 
deciduous  membrane,  is  rendered  shaggy  by  the  growth  of  villous  tufts  from 
the  surface  of  its  investing  chorion  (Plate  I.  Fig.  10,  /,  /).     Each  of  these 
tufts,  as  was  first  pointed  out  by  Prof.  Groodsir,2  is  composed  of  an  assemblage 
of  nucleated  cells,  which  are  found  in  various  stages  of  development ;  and  these 
are  always  inclosed  within  a  layer  of  basement-membrane,  which  seems  to  be 
itself  composed  of  flattened  cells  united  by  their  edges.     At  the  free  extremity 
of  each  villus  is  a  bulbous  expansion,  the  cells  composing  which  are  arranged 
round  a  central  spot ;  and  it  is  at  this  point  that  the  most  active  processes  of 
growth  take  place,  the  villus  elongating  by  the  development  of  new  cells  from 
its  germinal  spot,  and  (like  the  spongiole  of  the  plant)  drawing  in  nutriment 
from  the  soil  in  which  it  is  imbedded.     In  its  earliest  grade  of  development, 
the  chorion  and  its  villi  contain  no  vessels ;  and  the  fluid  drawn  in  by  the  tufts 
is  communicated  to  the  embryo,  by  the  absorbing  powers  of  the  germinal  mem- 
brane of  the  latter.     But  when  the  tufts  are  penetrated  by  bloodvessels,  and 
their  communication  with  the  embryo  becomes  more  direct,  the  means  by  which 
they  communicate  with  the  parent  are  found  to  be  still  essentially  the  same ; 
namely,  a  double  layer  of  nucleated  cells,  one  layer  belonging  to  the  foetal  tuft, 
and  the  other  to  the  vascular  maternal  surface.     It  is  from  these  elements  that 
the  Placenta  is  formed,  in  the  manner  next  to  be  described. 

980.  The  first  stage  in  this  process  consists  in  the  extension  of  the  foetal 
vessels  into  the  villi  of  the  Chorion  over  its  entire  surface,  in  the  manner  here- 
after to  be  detailed  (§  1001);  so  that  the  nutriment  which  these  villi  imbibe, 
instead  of  being  merely  added  to  the  albuminous  fluid  surrounding  the  yelk- 
bag,  is  now  conveyed  directly  to  the  embryo.     This — the  earliest  and  simplest 
mode  by  which  the  Foetus  effects  a  new  connection  with  the  parent — is  the  only 
one  in  which  it  ever  takes  place  in.  the  lower  Mammalia,  which  are  hence  pro- 
perly designated  as  "  non-placental,"  rather  than  as  ovo-viviparous.     In  the 
higher  Mammalia,  however,  there  soon  occurs  a  great  extension  of  the  vascular 

1  This  doctrine  was  first  announced  by  M.  Coste,  in  a  communication  to  the  Parisian 
Academy  of  Sciences,  on  the  basis  of  observations  on  two  Uteri  at  the  20th  and  25th  days 
of  gestation.     (See  "Comptes  Rendus,"  Mai  24,  1847.)     It  seems  to  be  altogether  that 
which  is  most  in  harmony  with  observed  facts;  and  especially  with  those  which  have  been 
noticed  by  Professors  Weber  and  Sharpey.     See,  also,  the  Memoir  of  M.  Robin,  on  the 
Mucous  Membrane  of  the  Uterus,  in  the  "  Archiv.  Gen.  deMed.,"  4e  Ser.,  torn.  xvii.  xviii. 

2  "Anatomical  and  Pathological  Observations,"  chap.  ix. 


ACTION   OF   THE    FEMALE. 


9Y5 


tufts  of  the  foetal  chorion,  at  certain  points ;  and  a  cor- 
responding adaptation,  on  the  part  of  the  uterine  struc- 
ture, to  afford  them  an  increased  supply  of  nutritious 
fluid.  These  specially  prolonged  portions  are  scattered, 
in  the  Ruminantia  and  some  other  Mammalia,  over  the 
whole  surface  of  the  chorion,  forming  what  are  termed 
the  "cotyledons;"  but  in  the  higher  orders,  and  in  Man, 
they  are  concentrated  in  one  spot,  forming  the  Placenta. 
In  some  of  the  lower  tribes,  the  maternal  and  the  foetal 
portions  of  the  placenta  may  be  very  easily  separated  ; 
the  former  consisting  of  the  thickened  decidua ;  and  the 
latter  being  composed  of  the  prolonged  and  ramifying 
vascular  tufts  of  the  chorion,  dipping  down  into  it.  But 
in  the  Human  placenta,  the  two  elements  are  mingled 
together  through  its  whole  substance. — On  looking  at 
the  foetal  surface  of  the  Human  placenta,  we  perceive 
that  the  Umbilical  vessels  diverge  in  every  direction  from 
the  point  at  which  they  enter  it ;  and  their  subdivisions 
form  a  large  mass  of  capillaries,  arranged  in  a  peculiar 
manner  (Fig.  254),  and  constituting  what  are  known 
as  the  foetal  mill.  Each  villus  contains  one  or  more 
capillary  loops,  communicating  with  an  artery  on  one 

Fig.  254. 


Fig.  253. 


The  extremity  of  a  Villus 
magnified  200  diameters.  Af- 
ter Weber.  The  loop  1  is  filled 
with  blood ;  the  other  loop,  2, 
is  empty ;  3  is  the  margin  of 
the  pellucid  villus. 


Portion  of  the  ultimate  ramifications  of  the  Umbilical  vessels,  forming  the  Foetal  Villi  of  the  Placenta. 

side  and  with  a  vein  on  the  other;  but  the  same  capillary  may  pass  into  several 
villi,  before  re-entering  a  larger  vessel.  The  capillaries  of  the  villi  are  covered, 
as  in  the  chorion,  by  a  layer  of  cells  (Fig.  255,  /),  inclosed  in  basement-mem- 
brane (e)  ',  but  the  foetal  tuft  thus  formed  is  inclosed  in  a  second  series  of  en- 
velops (a,  5,  c),  derived  from  the  maternal  portion  of  the  placenta  (Fig.  256), 
— a  space  (c£)  being  left,  however,  between  the  two,  at  the  extremity  of  the 
tuft. 

981.  Whilst  the  footal  portion  of  the  Placenta  is  thus  being  generated  by  the 
extension  of  the  vascular  tufts  of  the  chorion,  the  maternal  portion  is  formed  by 
the  enlargement  of  the  vessels  of  the  decidua,  between  which  they  dip  down. 
"These  vessels  assume  the  character  of  sinuses;  and  at  last  swell  out  (so  to 
speak)  around  and  between  the  villi ;  so  that  finally  the  villi  are  completely 
bound  up  or  covered  by  the  membrane  which  constitutes  the  walls  of  the  vessels, 
this  membrane  following  the  contour  of  all  the  villi,  and  even  passing  to  a  cer- 
tain extent  over  the  branches  and  stems  of  the  tufts.  Between  this  membrane, 
or  wall  of  the  enlarged  decidual  vessels,  and  the  internal  membrane  of  the  villi, 
there  still  remains  a  layer  of  the  cells  of  the  decidua."1  In  this  manner  is 


Prof.  Goodsir's  "Anatomical  and  Pathological  Observations,"  p.  60. 


976 


OF   GENERATION. 


formed  the  maternal  portion  of  the  placenta,  which  may  be  regarded  in  its  adult 
state  (as  was  well  pointed  out  by  Dr.  J.  Reid1)  in  the  light  of  a  large  sac  (Fig. 


Fig.  255. 


Fig.  256. 


Extremity  of  a  Plaoental  Yillus :  a,  external 
membrane  of  the  villus,  continuous  with  the 
lining  membrane  of  the  vascular  system  of  the 
mother ;  b,  external  cells  of  the  villus,  belong- 
ing to  the  placentaljdecidua:  c,  c,  germinal 
centres  of  the  external  cells ;  d,  the  space  be- 
tween the  maternal  and  foetal  portions  of  the 
villus;  e,  the  internal  membrane  of  the  villus, 
continuous  with  the  external  membrane  of  the 
chorion ;  /,  the  internal  cells  of  the  rillus,  be- 
longing to  the  chorion ;  g,  the  loop  of  umbilical 


Portion  of  the  external  membrane,  with 
the  external  cells  of  a  placental  villus ;— a, 
cells  seen  through  the  membrane ;  b,  cells 
seen  from  within  the  villus;  e,  cells  seen 
in  profile  along  the  edge  of  the  villus. 


259,  c)  formed  by  a  prolongation  of  the  inner  coat  of  the  uterine  vessels ;  against 
the  foetal  surface  of  which  sac,  the  tufts  just  described  may  be  said  to  push 
themselves,  so  as  to  dip  down  into  it,  carrying  before  them  a  portion  of  its  thin 
wall,  which  constitutes  a  sheath  to  each  tuft.  Now,  as  every  extension  of  the 


Fig.  257. 


Diagram  illustrating  the  arrangement  of  the  Placental  Decidua :  a,  decidua  in  contact  with  the  interior  of 
the  uterus;  b,  venous  sinus  passing  obliquely  through  it  by  a  valvular  opening;  c,  a  curling  artery  passing  in 
the  same  direction ;  d,  the  lining  membrane  of  the  maternal  vascular  system,  passing  in  from  the  artery  and 
vein,  lining  the  bag  of  the  placenta,  and  covering  e,  e,  the  foetal  tufts,  passing  on  to  them  from  their  stems 
from  the  foetal  side  of  the  cavity,  also  by  the  terminal  decidual  bars  /,/,  from  the  uterine  side,  and  from  one 
tuft  to  the  other  by  the  lateral  bar,  g ;  /*,  h,  separated  foetal  tufts,  showing  the  internal  membrane  and  cells, 
which,  with  the  loops  of  umbilical  vessels,  constitute  the  true  foetal  portion  of  the  tufts. 

uterine  vessels  carries  the  decidua  before  it,  every  one  of  the  vascular  tufts  that 
dips  down  into  it  will  be  covered  with  a  layer  of  the  cellular  structure  of  the 


1  "Edinb.  Med.  and  Surg.  Journ.,"  Jan.    1841 ;  and 
searches,"  chap.  vm. 


Anat.,  Phys.,  and  Pathol.  Re- 


ACTION   OP   THE   FEMALE. 


977 


latter;  and  the  foetal  portion  of  each  tuft  will  thus  be  inclosed  in  a  layer  of 
maternal  cells  and  basement-membrane  (Fig.  255,  a,  b,  c;  and  Fig.  256,  a,  I,  e). 
In  this  manner,  the  whole  interior  of  the  placental  cavity  is  intersected  by 
numerous  tufts  of  foetal  vessels,  disposed  in  fringes,  and  bound  down  by  reflec- 
tions of  the  delicate  membrane  that  forms  its  proper  wall ;  just  as  the  intestines 
are  held  in  their  places  by  the  reflections  of  the  peritoneum  that  covers  them. 
This  view  was  suggested  to  Dr.  R.  by  the  very  interesting  fact  that  the  tufts 
of  foetal  vessels  not  unfrequently  extend  beyond  the  uterine  surface  of  the  pla- 
centa, and  dip  down  into  the  uterine  sinuses  (Fig.  258);  where  they  are  still 
covered  and  held  in  their  places,  by  reflections  of  the  same  membrane.  All  the 
bands  which  connect  and  tie  down  the  tufts  (Fig.  257,  g)  are  formed  of  the 
same  elements  as  the  envelops  of  the  tufts  themselves ;  namely,  a  fold  of  the 
lining  membrane  of  the  decidual  sinuses,  and  a  layer  of  the  cellular  decidua. 

982.  The  blood  is  conveyed  into  the  Placental  cavity  by  the  "  curling  arteries" 
of  the  uterus  (Fig.  259,  a);  and  is  returned  from  it  by  the  large  veins,  that  are 
commonly  designated  as  sinuses  (Fig.  259,  6).  The  foetal  vessels,  being  bathed 
in  this  blood,  as  the  branchiae  of  aquatic  animals  are  in  the  water  that  surrounds 
them,  not  only  enable  the  foetal  blood  to  exchange  its  venous  character  for  the 
arterial,  by  parting  with  its  carbonic  acid  to  the  maternal  blood,  and  receiving 
oxygen  from  it;  but  they  also  serve  as  rootlets,  by  which  certain  nutritious  ele- 

Fig.  258. 


Fig.  259. 


Diagram  of  the  structure  of  the  Placenta;  showing  a,  the  substance  of  the  uterus;  6,  the  cavity  of  a  sinus; 
c,  c,  the  foetal  tufts  dipping  down  into  this;  d,  d,  the  decidual  lining  of  the  uterus;  e,  curling  arteries. 

ments  of  the  maternal  blood  (probably  those  composing  the  liquor  sanguinis) 
are  taken  into  the  system  of  the  foetus.  In  this,  they  closely  correspond  with 
the  villi  of  the  intestinal  canal ;  and  there  is  this  further  very  striking  analogy — 
that  the  nutrient  material  is  selected  and  prepared  by  two  sets  of  cells,  one  of 
which  (the  maternal)  transmits  it  to  the  other  (the  foetal),  in  the  same  manner 
as  the  epithelial  cells  of  the  intestinal  villi  seem  to  take  up  and  prepare  the 
nutrient  matter,  which  is  destined  to  be  still  further  assimilated  by  the  cells 
that  float  in  the  circulating  current  (§  461).  It  is  pro- 
bable, too,  that  the  placenta  is  to  be  regarded  as  an  ex- 
creting organ;  serving  for  the  removal,  through  the  ma- 
ternal blood,  of  excrementitious  matter  whose  continued 
circulation  through  the  blood  of  the  foetus  would  be  pre- 
judicial to  the  latter.  And  it  will  be  in  this  mode  that 
the  blood  of  the  mother  may  become  impregnated  with 
substances,  or  impressed  with  attributes,  originally  be- 
longing to  the  male  parent,  so  as  to  impart  these  to  the 
products  of  subsequent  conceptions  by  a  different  father 
(§  975).  There  is  no  more  direct  communication  between 
the  mother  and  foetus  than  that  which  is  afforded  by  this 
immersion  of  the  foetal  tufts  in  the  maternal  blood ;  all 
the  observations  which  have  been  supposed  to  prove  the 
existence  of  real  vascular  continuity,  having  been  falsi- 
62 


Diagram  of  the  Placental 
cavity,  according  to  Dr.  Reid : 
a,  curling  artery  of  the  ute- 
rus; fo,  uterine  sinus;  c,  cavity 
of  the  placenta;  d,  fuetal  tuft 
imbedded  in  it,  and  held  in 
place  by  reflections  of  its 
walls. 


978  OF   GENERATION. 

tied  by  the  extravasation  of  fluid,  probably  consequent  upon  the  force  used  in  inject- 
ing the  vessels.  Moreover,  the  different  size  of  the  blood-corpuscles  in  the  foetus 
and  in  the  parent  (§  149)  shows  the  non-existence  of  any  such  communication. 

983.  The  formation  of  the  Placenta,  in  the  manner  just  described,  commences 
in  the  latter  part  of  the  second  month ;  during  the  third,  the  organ  acquires  its 
proper  character ;  and  it  subsequently  goes  on  increasing  in  accordance  with  the 
growth  of  the  ovum.     Towards  the  end  of  the  term  of  gestation,  however,  it 
becomes  more  dense  and  less  vascular  ;  owing,  it  would  seem,  to  the  obliteration 
of  several  of  the  minuter  vessels,  which  are  converted  into  hard  fibrous  filaments. 
The  vessels  of  the  uterus  undergo  great  enlargement  throughout,  but  especially 
at  the  part  to  which  the  placenta  is  attached;  and  the  blood  in  moving  through 
them  produces  a  peculiar  murmur,  which  is  usually  distinctly  audible  at  an  early 
period  of  pregnancy,  and  may  be  regarded  (when  due  care  is  taken  to  avoid 
sources  of  fallacy)  as  one  of  its  most  unequivocal  positive  signs.     The  "  pla- 
cental  bruit"  is  thus  described  by  Dr.  Montgomery:1  "The  characters  of  this 
phenomenon  are,  a  low  murmuring  or  somewhat  cooing  sound,  resembling  that 
made  by  blowing  gently  over  the  lip  of  a  wide-mouthed  phial,  and  accompanied 
by  a  slight  rushing  noise,  but  without  any  sensation  of  impulse.     The  sound  is, 
in  its  return,  exactly  synchronous  with  the  pulse  of  the  mother  at  the  time  of 
examination ;  and  varies,  in  the  frequency  of  its  repetitions,  with  any  accidental 
variation  which  may  occur  in  the  maternal  circulation.     Its  situation  does  not 
vary  during  the  course  of  the  same  pregnancy ;  but  in  whatever  region  of  the 
uterus  it  is  first  heard,  it  will  in  future  be  found,  if  recognized  at  all — for  it  is 
liable  to  intermissions — at  least,  we  shall  occasionally  be  unable  to  hear  it  where 
we  have  already  heard  it  a  short  time  before,  and  where  we  shall  shortly  again 
recognize  it.     According  to  my  experience,  it  will  be  most  frequently  heard 
about  the  situation  of  the  Fallopian  tube  of  the  right  side ;  but  it  may  be  detected 
in  any  of  the  lateral  or  anterior  parts  of  the  uterus."     That  the  cause  of  this 
sound  exists  in  the  uterus  itself,  is  distinctly  proved  by  the  fact,  that  it  has 
been  heard  when  that  organ  was  so  completely  anteverted,  that  the  fundus  hung 
down  between  the  patient's  thighs.     A  sound  so  much  resembling  this  as  to  be 
scarcely  distinguishable  from  it  may  be  occasioned,  however,  by  a  cause  of  a 
very  different  nature — namely,  an  abdominal  tumor,  pressing  upon  the  aorta, 
iliac  arteries,  or  enlarged  vessels  of  its  own  ;  and,  in  doubtful  cases,  it  is  neces- 
sary to  give  full  weight  to  the  possibility  of  such  an  explanation.     The  sound 
may  be  imitated  at  any  time,  by  pressing  the  stethoscope  on  the  iliac  arteries. 
The  placental  bruit  has  been  not  unfrequently  heard  in  the  eleventh  week;  but 
it  cannot  generally  be  detected  before  the  fourth  month,  when  the  fundus  uteri 
rises  above  the  anterior  wall  of  the  pelvis. 

984.  The  amount   of  the  peculiar  tissue  of  the  Uterus   (§  305)  greatly 
increases  during  pregnancy.     At  the  same  time,  the  Mammary  gland  and  its 
appendages  undergo  a  fuller  development ;  and  from  this  a  valuable,  but  not 
unequivocal,  indication   of   pregnancy   may  be   drawn.     Occasional    shooting 
pains  in  the  MammaB  are  not  unfrequently  experienced  within  a  short  period 
after  conception ;  and  more  continued  tenderness  is  also  not  unusual.     A  sense 
of  distension  is  very  commonly  experienced  at  about  the  end  of  the  second 
month;  and  from  that  time  a  distinct  "knottiness"  usually  begins  to  present 
itself,  increasing  with  the  advance  of  pregnancy.     In  many  instances,  kowever, 
these  mammary  sympathies  are  entirely  absent ;  and  they  may  be  simulated  by 
changes  that  take  place  in  consequence  of  various  affections  of  the  uterus.     A 
change  of  color  in  the  areola  is  a  very  common,  but  not  an  invariable,  occur- 
rence in  the  early  months  of  pregnancy ;  but  another  sign  is  afforded  by  the 
areola  and  nipple,  which  is  of  more  value  because  more  constant — namely,  a 

1  "  Signs  of  Pregnancy,"  p.  121. 


ACTION   OF   THE   FEMALE.  979 

puffy  turgescence,  and  an  increased  development  of  the  little  glandular  follicles, 
or  tubercles,  which  commonly  secrete  a  dewy  moisture. — Many  other  changes 
in  the  constitution  take  place  during  pregnancy ;  indicated  by  the  buffiness  of 
the  blood,  the  irritability  of  the  stomach,  and  the  increased  excitability  of  the 
mind.  All  these,  however,  are  discussed  with  sufficient  amplification  in  works 
on  Obstetric  Medicine. 

985.  The  act  of  Conception,  being  one  of  a  purely  organic  nature,  is  not 
itself  productive  of  any  sensation  on   the  part  of  the  mother ;  but  there  are 
some  women  in  whom  it  is  attended  with  certain  sympathetic  affections,  such  as 
faintness,  vertigo,  &c.,  that  enable  them  to  fix  upon  the  particular  time  at 
which  it  has  taken  place.     From  that  period,  however,  the  mother  has  no  direct 
consciousness  of  the  change  going  on  in  the  uterus  (save  by  the  effects  of  its 
increasing  pressure  on  other  parts),  until  the  occurrence   of  what  is  termed 
"quickening/'     This  is  generally  described  as  a  kind  of  fluttering  movement, 
attended  with  some  degree  of  syncope  or  vertigo.     After  it  has  once  occurred, 
and  has  strongly  excited  attention,  it  is  occasionally  renewed  once  or  twice,  and 
then  gives  place  to  the  ordinary  movements  of  the  foetus.     Not  unfrequently, 
however,  no  movement  whatever  is  felt,  until  near  the  end  of  the  term  of  ges- 
tation, or  even  through  the  whole  of  it.     As  to  the   cause  of  the   sensation, 
Obstetricians  are  much  divided;  and  no  satisfactory  account  has  been  given  of 
it.     It  has  been  vulgarly  supposed  to  be  due  to  the  first  movement  of  the  foetus, 
which  was  imagined  then  to  become  possessed  of  an  independent  life :  and  the 
English  law  recognizes   the  truth   of  this   doctrine,  in  varying  the    punish- 
ment of  an  attempt  to  procure  Abortion,  according  to  whether  the  woman 
be  " quick  with  child"  or  not;  and  in  delaying  execution  when  a  woman  can 
be  proved  to  be  so,  though  it  is  made  to  proceed  if  she  is  not,  even  if  she  be 
unquestionably  pregnant.     Whether  or  not  the  first  sensible  notions  of  the 
foetus  are  the  cause  of  the  peculiar  feeling  in  question,  there  can  be  no  doubt 
that  the  embryo  has  as  much  independent  vitality  before,  as  after,  the  quicken- 
ing.    From  the  time  that  the  ovum  quits  the  ovary,  it  ceases  to  be  a  part  of 
the  parent,  and  is  dependent  on  it  only  for  a  due  supply  of  nourishment,  which 
it  converts,  by  its  own  inherent  powers,  into  its  proper  fabric.     This  depend- 
ence cannot  be  said  to  cease  at  the  moment  of  quickening;  for  the  connection 
must  be  prolonged  during  several  weeks,  before  the  foetus  becomes  capable  of 
sustaining  life  without  such  assistance.     The  earliest  period  at  which  this  may 
occur  will  be  presently  considered  (§  990). 

986.  At  the  conclusion  of  about  nine  (solar)  months  from  the  period  of  con- 
ception, the  time  of  Parturition  arrives.     In  this  act,  the  muscular  walls  of  the 
uterus  are  primarily  concerned ;  for  a  kind  of  peristaltic  contraction  takes  place 
in  them,  the  tendency  of  which  is  to  press  the  contents  of  the  cavity  from  the 
fundus  towards  the  os  uteri,  and  finally  to  expel  them ;  and  this  contraction  is 
alone  sufficient  to  empty  the  uterus,-  when  no  impediment  is  presented  to  the 
exit  of  the  foetus,  as  we  see  in  the  occasional  occurrence  of  post-mortem  parturi- 
tion.    It  is,  in  fact,  in  the  contraction  of  the  fibres  of  the  fundus  and  body  of 
the  uterus,  and  in  a  relaxation  of  those  about  the  cervix  (which  relaxation  is 
something  quite  different  from  a  mere  yielding  to  pressure,  and  is  obviously  a 
vital  phenomenon  that  marks  a  peculiarity  in  the  actions  of  this  part),  that  the 
first  stage  of  an  ordinary  labor  essentially  consists.     There  is  no  proof  what- 
ever that  these  changes  are  dependent  upon  nervous  influence;  in  fact,  there  is 
much  evidence  that  the  parturient  action  of  the  uterus  is  not  the  result  (as  some 
have  maintained  it  to  be)  of  a  "  reflex"  action  of  the  Spinal  Cord,  but  is  due  to 
its  inherent  contractility;  for  numerous  instances  have  occurred,  in  which  nor- 
mal parturition  has  taken  place,  notwithstanding  the  destruction  of  the  lower 
part  of  the  Cord,  or  the  existence  of  a  state  of  complete  paraplegia  which 
marked  its  functional  inactivity;  and  the  continuance  of  the  peristaltic  action 


980  OF   GENERATION. 

for  some  time  after  somatic  death,  when  neither  the  Cerebro-spinal  nor  the 
Sympathetic  system  can  afford  any  supply  of  nervous  power,  is  yet  a  more  satis- 
factory proof  of  the  same  position.  Nevertheless,  it  seems  quite  certain  that 
muscular  contractions  of  the  uterus  may  be  induced  by  reflex  action ;  for  in  no 
other  way  can  we  account  for  numerous  phenomena,  which  distinctly  mark  the 
operation  of  remote  causes  acting  through  the  nervous  system,  such  as  the  in- 
duction of  uterine  contractions  by  the  dash  of  cold  water  on  the  abdominal  sur- 
face, by  the  injection  of  cold  water  into  the  vagina,  by  the  ingestion  of  cold 
water  into  the  stomach,  or  even  by  dipping  the  hands  into  cold  water,  or  again 
by  the  suctorial  application  of  the  infant's  lips  to  the  nipple,  by  the  introduction 
of  the  hand  into  the  vagina,  by  violent  movements  of  other  parts  of  the  body, 
and  by  various  other  means.  This  general  fact  has  an  important  practical 
bearing ;  since  there  are  various  occasions  on  which  it  is  most  important  to  life, 
that  the  previously  flaccid  uterus  should  be  excited  to  vigorous  contraction,  for 
the  sake  of  accelerating  parturition  or  of  suppressing  hemorrhage ;  whilst,  on 
the  other  hand,  it  is  often  no  less  important  to  be  able  to  prevent  or  to  antago- 
nize the  operation  of  causes  which  would  prematurely  induce  uterine  contrac- 
tions, to  the  destruction  of  the  offspring  and  the  danger  of  the  mother.  When, 
in  the  normal  act  of  Parturition,  the  head  has  so  far  made  its  way  through  the 
os  uteri  as  to  begin  to  distend  the  lower  part  of  the  genital  canal,  a  new  kind  of 
expulsive  effort  is  superadded  to  that  of  the  uterus  itself;  the  assistance  of  the 
Expiratory  muscles  being  then  called  in  (§  723),  through  the  intermediation  of 
the  Spinal  Cord,  which  is  probably  excited  to  this  action  by  the  stimulus  thus 
applied  to  the  afferent  nerves  of  the  compressed  parts;  and  it  is  chiefly  by  the 
instrumentality  of  these  muscles,  that  the  normal  act  of  parturition  is  usually 
completed.  The  same  action  which  expels  the  foetus  also  detaches  the  placenta; 
and  if  the  uterus  contract  with  sufficient  force  after  this  has  been  thrown  off, 
the  orifices  of  the  vessels  which  communicated  with  it  are  so  effectually  closed, 
that  little  or  no  hemorrhage  takes  place.  If,  however,  the  uterus  does  not  con- 
tract, or  relaxes  after  having  contracted,  a  large  amount  of  blood  may  be  lost 
in  a  short  time  from  the  open  orifices.  For  some  little  time  after  parturition,  a 
sero-sanguineous  discharge,  termed  the  lochia,  is  poured  out  from  the  uterus; 
and  this  commonly  contains  shreds  of  the  deciduous  membrane,  which  had  not 
been  previously  detached,  together  with  a  quantity  of  fat  globules,  and  of  other 
products  of  disintegration  of  the  uterine  tissue  (§  593).  *  Within  a  few  weeks 
after  delivery,  the  uterus  regains  (at  least  in  a  healthy  subject)  its  previous  con- 
dition; and  it  is  probable  that  the  portion  of  its  mucous  membrane  which  had 
been  thrown  off  as  Decidua,  is  very  early  reproduced. 

987.  As  to  the  reason  why  the  period  of  Parturition  should  be  just  nine 
months  after  the  occurrence  of  Conception,  we  know  nothing  more  than  we  do 
of  that  of  similar  periodical  phenomena  in  the  history  of  the  life  of  Man  and 
of  other  living  beings ;  all  of  which  must  be  considered  as  occasional  manifesta- 
tions of  changes  that  are  constantly  in  progress,  whose  rate,  being  dependent 
upon  the  degree  of  Heat  supplied,  is  so  uniform  in  warm-blooded  animals  as  to 
secure  a  very  close  conformity  to  a  common  standard.3  There  is  evidence  that 

1  In  addition  to  the  evidence  already  cited,  of  the  rapid  occurrence  of  fatty  degenera- 
tion of  the  uterine  structure  after  parturition,  the  Author  may  mention  that  he  has  been 
informed  by  Dr.  Retzius  (Professor  of  Midwifery  at  Stockholm)  that  he  has  detected  a 
large  number  of  fat  globules  in  the  urine  of  puerperal  women.     Is  it  not  possible,  it  may 
be  further  asked,  that  some  of  the  oleaginous  matter  so  copiously  poured  forth  by  the 
mammary  glands,  may  be  derived  from  this  source  ?     Such  an  economy  of  nutrient  mate- 
rial would  be  consistent  with  what  we  elsewhere  meet  with  ;  and  the  idea  is  conformable 
to  the  faet,  that  the  proportion  of  butyrine  in  the  milk  is  much  greater  in  the  earlier, 
than  in  the  later  months  of  lactation. 

2  This  may  be  best  illustrated  by  the  analogy  of  a  Ley  den  jar  which  is  being  charged 
by  the  continuous  action  of  an  Electrical  Machine,  and  which  is  so  arranged  as  to  c/wcharge 


ACTION   OP   THE   FEMALE.  981 

the  occurrence  of  the  uterine  nisus  may  be  induced  by  a  variety  of  causes, 
several  of  which  probably  concur  in  the  normal  act  of  Parturition.  For,  in  the 
first  place,  the  state  of  development  of  the  muscular  substance  of  the  uterus 
can  scarcely  be  without  a  considerable  influence  on  this  operation.  We  see  it 
undergoing  a  gradual  augmentation  during  the  period  of  pregnancy,  without  any 
demand  being  made  upon  its  functional  activity ;  it  gradually  becomes  more  and 
more  irritable,  contractions  being  far  more  readily  excited  in  it  by  electrical  or 
other  stimulation,  in  the  later,  than  in  the  earlier  months  of  pregnancy;  and  at 
last  this  irritability  seems  to  reach  its  acme,  in  virtue  of  the  nutritive  changes 
which  have  been  progressively  taking  place  in  it,  and  to  discharge  itself  in  one 
powerful  effort. — That  the  parturient  effort,  however,  is  not  solely  dependent 
upon  the  state  of  development  of  the  Uterus,  appears  from  several  considera- 
tions :  and,  in  the  first  place,  from  the  very  curious  fact  that,  in  cases  of  Extra- 
uterine  pregnancy,  contractions  resembling  those  of  labor  take  place  in  its  walls. 
Moreover,  various  states  of  constitution,  especially  that  which  is  designated  as 
irritability,  may  induce  the  occurrence  of  the  parturient  efforts  at  an  earlier 
period;  and  this  constitutes  Abortion,  or  Premature  Delivery,  according  to  the 
viability  of  the  child.  There  are  some  women,  in  whom  this  regularly  happens 
at  a  certain  month,  so  that  it  seems  to  be  an  action  natural  to  them ;  but  it  is 
always  to  be  prevented,  if  possible,  being  injurious  alike  to  the  mother  and  the 
child ;  and  this  prevention  is  to  be  attempted  by  rest  and  tranquillity  of  mind 
and  body,  and  by  a  careful  avoidance  of  all  the  exciting  causes  which  may  pro- 
duce uterine  contractions  by  their  operation  on  the  Nervous  system.  Among 
the  causes  of  Abortion,  however,  the  death  of  the  foetus,  or  an  abnormal  state  of 
the  placeutal  structure,  is  one  of  the  most  common;  and  thus  we  have  a  very 
distinct  proof  of  the  influence  which  the  state  of  the  contents  of  the  uterus  has 
on  the  induction  of  parturient  effort.  In  fact,  what  may  be  termed  the  matu- 
ration of  the  uterus  and  its  contents — a  condition  analogous  to  that  which  pre- 
cedes the  dropping  of  ripe  fruit,  and  which  is  acquired  by  the  completion  of  the 
developmental  process — appears  to  have  more  influence  in  determining  the 
normal  parturient  effort,  than  any  other  cause  which  can  be  assigned.  Certain 
preparatory  changes  are  known  to  be  taking  place  in  the  uterus  itself  during 
the  last  two  or  three  weeks  of  gestation ;  for  its  upper  part  contracts  itself  more 
closely  around  its  contents,  as  if  it  were  bracing  itself  up  for  the  coming 
encounter;  whilst  there  is  a  greater  disposition  to  relaxation  of  its  lower  part, 
as  also  in  the  soft  parts  surrounding  the  orifice  of  the  pelvis,  so  that  the  whole 
mass  descends.  It  is  well  known  that  there  is  far  less  aptitude  for  dilatation  in 
the  os  uteri  before  this  change  takes  place ;  so  that  premature  labors  are  fre- 
quently rendered  very  difficult  and  tedious  by  the  resistance  which  the  foetus 
encounters  from  the  soft  parts,  notwithstanding  that  its  smaller  size  enables  it 
to  pass  more  readily  through  the  pelvic  canal.  The  placenta  of  the  fully 
developed  foetus,  again,  is  somewhat  in  the  condition  of  the  footstalk  of  a 
ripening  fruit;  that  is,  having  attained  its  full  evolution  as  an  organ  of  tem- 
porary function,  its  connection  tends  to  become  dissevered  in  virtue  of  the 
further  changes  which  take  place  in  itself,  quite  irrespectively  of  any  external 
agency.1  This  is  very  strikingly  evinced  by  the  fact,  that  when  the  uterus 
contains  two  foetuses,  and  one  of  them  is  expelled — either  in  consequence  of 
impeded  development  or  of  disease  in  itself,  or  because  it  has  attained  its  own 

itself  spontaneously  whenever  the  disturbance  in  its  equilibrium  attains  a  certain  intensity. 
If  the  movement  of  the  machine  be  uniform,  and  other  conditions  remain  the  same,  the 
discharge  will  take  place  at  regular  intervals. 

1  Such  a  change  may  be  easily  verified  in  the  placenta  of  many  of  the  lower  animals, 
such  as  the  cat,  in  which  the  foetal  and  maternal  portions  remain  more  distinct  than  they 
do  in  the  human  female ;  for  these  become  far  more  easily  separable  from  each  other,  as 
the  period  of  parturition  draws  near,  than  they  are  at  any  previous  time. 


982  OP   GENERATION. 

full  term  of  development  (as  in  cases  of  superfcetation,  §  990) — the  other,  if  its 
development  at  this  period  is  far  from  complete,  is  often  retained,  and  goes  on 
to  its  full  term,  its  placenta  not  being  detached  in  the  first  parturient  effort, 
because  it  was  not  then  prepared  for  the  separation.  It  is  obvious  that  this 
view  affords  a  rational  explanation  of  the  occurrence  of  uterine  action  in  cases 
of  extra-uterine  foetation;  for,  if  the  condition  of  the  placental  attachment 
furnish  its  exciting  cause,  it  will  do  so  equally,  whether  the  placenta  be 
attached  to  the  lining  of  the  uterus,  or  to  that  of  the  Fallopian  tube,  or  to  any 
other  organ.  It  is  an  additional  indication  that  the  immediate  stimulus  to  the 
parturient  effort  of  the  uterus  is  given  by  some  change  in  the  condition  of  its 
foetal  connections,  that  the  term  of  gestation  seems  capable  of  being  prolonged 
by  peculiarities  in  the  constitution  or  rate  of  development  of  the  foetus,  which 
are  derived  from  the  male  parent ;  for  it  was  ascertained  by  the  late  Earl  Spen- 
cer,1 that  of  75  cows  in  calf  by  a  particular  bull,  the  average  period  was  288  J 
days,  instead  of  280 ;  none  of  these  having  gone  less  than  281  days,  and  two- 
fifths  of  them  having  exceeded  289  days.2 

988.  Although  the  duration  of  Pregnancy  is  commonly  stated  at  nine  solar 
months,  it  would  be  more  correct  to  fix  the  period  at  40  weeks,  or  280  days ; 
which  exceeds  nine  calendar  months  by  from   5   to  7  days,  according  to  the 
months  included.3     This,  at  least,  is  the  average  result  of  observation,  in  cases 
in  which  the  period  of  Conception  could  be  fixed,  from  peculiar  circumstances, 
with  something  like  certainty ;  but  there  can  be  no  doubt  that  variations  of  a 
few  days,  more  or  less,  are  of  continual  occurrence.     The  period  of  Quickening 
may  be  relied  on  in  some  women,  in  whom  it  occurs  with  great  regularity  in  a 
certain  week  of  Pregnancy;  but  in  general  there  is  great  latitude  as  to  the  time 
of  its  occurrence.     The  usual  or  average  time  is  probably  about  the  18th  week. 

989.  The  question  of  the  extreme  limit  of  Gestation  is  one  of  great  import- 
ance both  to  the  Practitioner  and  to  the  Medical  Jurist ;  but  it  is  one  which 
cannot  yet  be  regarded  as  satisfactorily  decided.     Many  persons,  whose  expe- 
rience should  give  much  weight  to  their  opinion,  maintain   that   the  regular 
period  of  40  weeks  is  never  extended  for  more  than  two  or  three  days ;  whilst, 

1  See  Dr.  J.  C.  Hall  in  "Medical  Gazette,"  May  6,  1842. 

2  The  very  ingenious  doctrine  has  been  propounded  by  Dr.  Tyler  Smith  ("Parturition, 
and  the  Principles  and  Practice  of  Obstetrics,"  London,  1849),  that  the  exciting  cause  of 
parturition  is  to  be  found  in  the  recurrence  of  the  periodical  excitement  of  the  ovary,  act- 
ing by  reflection  on  the  uterus  through  the  spinal  system  of  nerves,  the  ovarian  nerves 
being  the  exciters  and  the  uterine  the  motors;  this  excitement  continuing  during  the  entire 
period  of  gestation,  and  giving  a  special  tendency  to  abortion  at  each  return ;  and  acting 
with  such  potency  at  the  eleventh  recurrence  as  then  to  induce  the  parturient  effort.     He 
assigns  no  other  cause,  however,  why  this  eleventh  recurrence  should  be  so  much  more 
effectual  than  the  rest,  than  that  by  this  time  there  is  a  much  greater  aptitude  to  con- 
traction in  the  uterus  itself,  and  an  increased  readiness  to  be  thrown  off  on  the  part  of  the 
placenta — conditions  which  seem  to  the  Author  to  be  in  themselves  adequate  to  account 
for  the  result.     Dr.  Tyler  Smith's  hypothesis  is  distinctly  negatived  by  the  following  facts: 
1.  The  period  of  gestation,  although  commonly  a  multiple  of  the  menstrual  interval,  is  by 
no  means  constantly  so  ;   the  former  remaining  normal  when  the  latter  is  shorter  or  longer 
than  usual.     2.  Parturient  efforts  take  place  in  the  uterus,  notwithstanding  the  previous 
removal  of  the  lower  part  of  the  spinal  cord.     3.   The  removal  of  the  ovaries  in  the  later 
part  of  gestation  does  not  interpose  the  least  check  to  the  parturient  action,  as  Prof. 
Simpson,  of  Edinburgh,  has  experimentally  ascertained.     The  Author  considers  himself 
fully  justified,  therefore,  in  asserting  that  this  hypothesis  does  not  possess  the  slightest 
claim  even  to  be  entertained  as  a  possible  one ;  and  would  refer,  for  a  more  detailed  exami- 
nation of  it,  to  the  "Brit,  and  For.  Med.-Chir.  Review,"  vol.  iv.  p.  1. 

3  The  mode  of  reckoning  customary  among  women,  is  to  date  from  the  middle  of  the 
month  after  the  last  appearance  of  the  Catamenia  ;   but  it  is  certain  that  Conception  is 
much  more  likely  to  take  place  soon  after  they  have  ceased  to  flow,  or  even  just  before 
their  access,  than  in  the  intervening  period  ($  966)  ;   so  that,  in  most  instances,  it  would 
be  most  correct  to  expect  labor  at  forty  weeks  and  a  few  days  after  the  last  recurrence  of 
the  Menses. 


ACTION   OF   THE   FEMALE.  983 

on  the  other  hand,  there  are  numerous  cases,  on  record,  which,  if  testimony  is 
to  be  believed  at  all  (and  in  many  of  these,  the  character  and  circumstances  of 
the  parties  place  them  above  suspicion),  furnish  ample  evidence  that  Gestation 
may  be  prolonged  for  at  least  three  weeks  beyond  the  regular  term.1  The 
English  law  fixes  no  precise  limit ;  and  the  decisions  which  have  been  given  in 
our  courts,  when  questions  of  this  kind  have  been  raised,  have  been  mostly 
formed  upon  the  collateral  circumstances.  The  law  of  France  provides  that  the 
legitimacy  of  a  child  born  within  300  days  after  the  death  or  departure  of  the 
husband  shall  not  be  questioned ;  and  a  child  born  after  more  than  300  days  is 
not  declared  a  bastard,  but  its  legitimacy  may  be  contested.  By  the  Scotch 
law,  a  child  is  not  declared  a  bastard  unless  born  after  the  tenth  month  from 
the  death  or  departure  of  the  husband. — Very  important  evidence  on  this  sub- 
ject is  afforded  by  observations  on  the  lower  animals,  which  are  free  from  those 
sources  of  fallacy  which  attend  human  testimony.  The  observations  of  Tessier, 
which  were  continued  during  a  period  of  forty  years,  with  every  precaution 
against  inaccuracy,  have  furnished  a  body  of  results  which  seems  quite  decisive. 
In  the  Cow,  the  ordinary  period  of  gestation  is  about  the  same  as  in  the  Human 
female ;  but  out  of  577  individuals,  no  less  than  20  calved  beyond  the  298th 
day,  and  of  these,  some  went  on  to  the  321st,  making  an  excess  of  nearly  six 
weeks.  Of  447  Mares,  whose  natural  period  of  gestation  is  about  335  days, 
42  foaled  between  the  359th  and  the  419th  days,  the  greatest  protraction  being 
thus  84  days,  or  just  one-fourth  of  the  usual  term.  Of  912  Sheep,  whose 
natural  period  is  about  151  days,  96  yeaned  beyond  the  153d  day;  and  of  these 
7  went  on  until  the  157th  day,  making  an  excess  of  6  days.  Of  161  Rabbits, 
whose  natural  period  is  about  thirty  days,  no  fewer  than  25  littered  between  the 
3iJd  and  35th ;  the  greatest  protraction  was  here  one-sixth  of  the  whole  period, 
and  the  proportion  in  which  there  was  a  manifest  prolongation  was  also  nearly 
one-sixth  of  the  total  number  of  individuals.  In  the  incubation  of  the  common 
Hen,  Tessier  found  that  there  was  not  unfrequently  a  prolongation  to  the 
amount  of  three  days,  or  one-seventh  of  the  whole  period. — In  regard  to  Cows, 
the  observations  of  Tessier  have  been  confirmed  by  those  of  Earl  Spencer,  who 
has  published3  a  table  of  the  period  of  gestation  as  observed  in  764  individuals; 
he  considers  the  average  period  to  be  284  or  285  days ;  but  no  fewer  than  310 
calved  after  the  285th  day;  and  of  these,  3  went  on  to  the  306th  day,  and  1  to 
the  313th.  It  is  curious  that  among  the  calves  born  between  the  290th  and 
300th  days,  there  was  a  decided  preponderance  of  males — these  being  74  to  32 
females ;  whilst  all  of  those  born  after  the  300th  day  were  females.  The  addi- 
tional series  of  observations  subsequently  made  by  Earl  Spencer,  in  regard  to  the 
constant  protraction  of  the  period  in  75  cows  in  calf  by  a  particular  bull,  has 
been  already  noticed  (§  987). — Another  series  of  observations  has  been  published 
by  Mr.  C.  N.  Bement,  of  Albany,  U.  S.,3  who  has  recorded  the  period  of  gesta- 
tion of  62  cows.  The  longest  period  was  336  days ;  the  shortest,  213  days. 
The  average  period  for  male  calves  was  288  days;  and  for  females,  282  days. — 
On  the  whole,  it  may  be  considered,  that  in  regard  to  the  Human  female,  the 
French  law  is  a  very  reasonable  one ;  and  there  is  quite  sufficient  analogical 
evidence  to  support  the  assertions  of  females  of  good  character,  having  no 
motive  to  deceive,  which  lead  to  the  conclusion  that  a  protraction  of  at  least 
four  weeks  is  quite  possible,  and  that  a  protraction  to  the  extent  of  six  weeks  is 
scarcely  to  be  denied.4 

1  A  good  collection  of  such  cases  will  be  found  in  Dr.  Montgomery's  excellent  work  on 
the  "  Signs  of  Pregnancy,"  and  in  Dr.  A.  Taylor's  "Medical  Jurisprudence." 

2  "Journal  of  the  English  Agricultural  Society,"  1839. 

3  "American  Journal  of  the  Medical  Sciences,"  October,  1845. 

4  See  especially  two  cases,  183  and  184,  detailed  by  Dr.  Murphy  in  his  "Report  of  the 
Obstetric  Practice  of  University  College  Hospital"  for  1844  ;  and  another  case  since  pub- 
lished by  him  in  the  "  Medical  Gazette"  for  1849,  vol.  xlviii.  p.  683. 


984  OF   GENERATION. 

990.  In  regard  to  the  shortest  period  at  which  Gestation  may  terminate, 
consistently  with  the  viability  of  the  Child,  there  is  a  still  greater  degree  of 
uncertainty.  Most  practitioners  are  of  opinion,  that  it  is  next  to  impossible 
for  a  foetus  to  live  and  grow  to  maturity,  which  has  not  nearly  completed  its 
seventh  month  ;  but  it  is  unquestionable  that  infants  born  at  a  much  earlier 
period  have  lived  for  some  months,  or  even  to  adult  age.  It  is  rare  in  such 
cases,  however,  that  the  date  of  conception  can  be  fixed  with  sufficient  precision 
to  enable  a  definite  statement  to  be  given.  Of  the  importance  of  the  question, 
a  case  which  some  time  since  occurred  in  Scotland  affords  sufficient  proof.  A 
vast  amount  of  contradictory  evidence  was  adduced  on  this  trial ;  but,  on  the 
general  rule  of  accepting  positive  in  preference  to  negative  testimony,  it  seems 
that  we  ought  to  consider  it  possible  that  a  child  may  live  for  some  months, 
which  has  been  born  at  the  conclusion  of  24  weeks  of  gestation.  In  the  case 
in  question,  the  Presbytery  decided  in  favor  of  the  legitimacy  of  an  infant  born 
alive  within  25  weeks  after  marriage.1  A  very  interesting  case  is  on  record/* 
in  which  the  mother  (who  had  borne  five  children)  was  confident  that  her  period 
of  gestation  was  less  than  19  weeks ;  the  facts  stated  respecting  the  develop- 
ment of  the  child  are  necessarily  very  imperfect,  as  it  was  important  to  avoid 
exposing  his  body,  in  order  that  his  temperature  might  be  kept  up ;  but  at  the 
age  of  three  weeks,  he  was  only  13  inches  in  length,  and  his  weight  was  no 
more  than  29  oz.  At  that  time,  he  might  be  regarded,  according  to  the  calcu- 
lation of  the  mother,  as  corresponding  with  an  infant  of  22  weeks  or  5?  months; 
but  the  length  and  weight  were  greater  than  are  usual  at  that  period,  and  he  must 
have  been  probably  born  at  about  the  25th  week.  It  is  an  interesting  feature 
in  this  case,  that  the  calorific  power  of  the  infant  was  so  low,  that  artificial  heat 
was  constantly  needed  to  sustain  it ;  but  that,  under  the  influence  of  heat  of 
the  fire,  he  evidently  became  weaker,  whilst  the  warmth  of  a  person  in  bed 
rendered  him  lively  and  comparatively  strong.  During  the  first  week,  it  was 
extremely  difficult  to  get  him  to  swallow ;  and  it  was  nearly  a  month  before  he 
could  suck.  At  the  time  of  the  report,  he  was  four  months  old,  and  his  health 
appeared  very  good. — Another  case  of  very  early  viability  has  been  more  re- 
cently put  on  record  by  Mr.  Dodd  :3  in  this,  as  in  the  former  instance,  the 
determination  of  the  child's  age  rests  chiefly  on  the  opinion  of  the  mother ;  but 
there  appears  no  reason  for  suspecting  any  fallacy.  The  child  seems  to  have 
been  born  at  the  26th  or  27th  week  of  gestation  ;  and  having  been  placed  under 
judicious  management,  it  has  thriven  well. — One  of  the  most  satisfactory  cases 
on  record  is  that  detailed  by  Dr.  Outrepont*  (Professor  of  Obstetrics  at  Wurz- 
burg),  and  stated  by  Dr.  Christison  in  his  evidence  on  the  case  first  alluded 
to.  The  evidence  is  as  complete  as  it  is  possible  to  be  in  any  case  of  the  kind; 
being  derived  not  only  from  the  date  assigned  by  the  mother  to  her  conception, 
but  also  from  the  structure  and  history  of  the  child.  The  gestation  could  have 
only  lasted  27  weeks,  and  was  very  probably  less.  The  length  of  the  child  was 
13 1  inches,  and  its  weight  was  24  oz.  Its  development  was  altogether  slow  ;  and 
at  the  age  of  eleven  years,  the  child  seemed  no  more  advanced  in  body  or  mind 
than  most  other  lads  of  seven  years  old.  In  this  last  point,  there  is  a  very 
striking  correspondence  with  the  results  of  other  observations  upon  premature 
children,  made  at  an  earlier  age.  A  very  remarkable  case  has  been  since  put 
on  record  by  Dr.  Barker  of  Dumfries,5  in  which  the  child  is  affirmed  to  have 
been  born  on  the  158th  day  of  gestation,  or  in  the  middle  of  the  twenty-third 
week  after  intercourse.  Its  size,  weight,  and  grade  of  development  were  con- 

«  Report  of.  Proceedings  against  the  Rev.  Fergus  Jardine,"  Edinburgh,  1839. 

'Edinb.  Med.  and  Surg.  Journal,"  vol.  xi. 

'Provincial  Medical  and  Surgical  Journal,"  vol.  ii.  p.  474. 

'Henke's  Zeitschrift,"  band  vi. 

'  Medical  Times,"  Sept.  7  and  Oct.  12,  1850. 


DEVELOPMENT  OF  THE  EMBRYO.  985 

formable  to  the  asserted  period  :  for  it  weighed  only  1  Ib.  and  measured  11 
inches;  it  had  only  rudimentary  nails,  and  scarcely  any  hair  except  a  little  of 
reddish  color  on  the  back  of  the  head  ;  the  eyelids  were  closed,  and  did  not 
open  until  the  second  day  ;  the  skin  was  shrivelled.  When  born  it  was  wrapped 
up  in  a  box  and  placed  before  the  fire.  The  child  did  not  suck  properly  until 
after  the  lapse  of  a  month,  and  did  not  walk  until  she  was  nineteen  months  old. 
Three  years  and  a  half  afterwards,  this  child  was  in  a  thriving  state,  and  very 
healthy,  but  of  small  make ;  sh'e  then  weighed  29 \  Ibs. 

991.  There  is  another  question  regarding  the  function  of  the  Female  in  the 
Reproductive  act,  which  is  of  great  interest  in  a  scientific  point  of  view,  and 
which  may  become  of  importance  in  Juridical  inquiries  :  namely,  the  possi- 
bility of  Superf cetation,  that  is,  of  two  distinct  conceptions  at  an  interval  of 
greater  or  less  duration ;  so  that  two  foetuses  of  different  ages,  the  offspring  per- 
haps of  different  parents,  may  exist  in  the  uterus  at  the  same  time. — The  sim- 
plest case  of  Superfcetation,  the  frequent  occurrence  of  which  places  it  beyond 
reasonable  doubt,  is  that  in  which  a  female  has  intercourse  on  the  same  day 
with  two  males  of  different  complexions,  and  bears  twins  at  the  full  time ;  the 
two  infants  resembling  the  two  parents  respectively.     Thus,  in  the  slave  States 
of  America,  it  is  not  uncommon  for  a  black  woman  to  bear  at  the  same  time  a 
black  and  a  mulatto  child ;  the  former  being  the  offspring  of  her  black  husband, 
and  the  latter  of  her  white  paramour.     The  converse  has  occasionally,  though 
less  frequently  occurred  :  a  white  woman  bearing  at  the  same  time  a  white  and 
a  mulatto  child.     There  is  no  difficulty  in  accounting  for  such  facts,  when  it  ig 
remembered  that  nothing  has  occurred  to  prevent  the  uterus  and  ovaria  from 
being  as  ready  for  the  second  conception  as  for  the  first ;  since  the  orifice  of  the 
former  is  not  yet  closed  up ;  and,  at  the  time  when  one  ovum  is  matured  for 
fecundation,  there  are  usually  more  in  the  same  condition. — But  it  is  not  easy 
thus  to  account  for  the  birth  of  two  children,  each  apparently  mature,  at  an 
interval  of  five  or  six  months ;   since  it  might  have  been  supposed  that  the 
uterus  was  so  completely  occupied  with  the  first  ovum,  as  not  to  allow  of  the 
transmission  of  the  seminal  fluid  necessary  for  the  fecundation  of  the  second. 
In  cases  where  two  children  have  been  produced  at  the  same  time,  one  of  which 
was  fully  formed,  whilst  the  other  was  small  and  seemingly  premature,  there  is 
no  occasion  whatever  to  imagine  that  the  two  were  conceived  at  different  periods; 
since  the  smaller  foetus  may  have  been  "blighted,"  and  its  development  re- 
tarded, as  not  unfrequently  happens  in  other  cases.     Nor  is  it  necessary  to  infer 
the  occurrence  of  Superfoetation  in  every  case,  in  which  a  living  child  has  been 
produced  a  month  or  two  after  the  birth  of  another  ;  since  the  latter  may  have 
been  somewhat  premature,  whilst  the  former  has  been  carried  to  the  full  term. 
But  such  a  difference  can  scarcely  be,  at  the  most,  more  than  2£  or  3  months; 
and  there  are  several  cases  now  on  record,  in  which  the  interval  was  from  110 
to  170  days,  whilst  neither  of  the  children  presented  any  indication  of  being 
otherwise  than  mature.1 

4. — Development  of  the  Embryo. 

992.  The  history  of  the  evolution  of  the  germ,  from  its  first  appearance  as  a 
single  cell  lying  in  the  midst  of  the  yelk,  to  the  time  when  it  presents  the  form 
and  structure  characteristic  of  its  parent  species,  and  is  capable  of  maintaining 
an  independent  existence — including  the  details  of  the  progressive  development 
of  each  separate  organ  and  tissue,  from  its  first  appearance  as  an  aggregation  of 
simple  cells  formed  by  the  duplicative  subdivision  of  the  primordial  vesicle,  to 

1  See  the  Article  "  Superfoetation,"  in  Dr.  Beck's  "Elements  of  Medical  Jurispru- 
dence." 


986  OP   GENERATION. 

that  stage  of  completeness  in  which  it  is  able  to  bear  a  part  in  the  vital  economy 
of  the  new  being — and  embracing,  also,  the  succession  of  changes  in  the  pro- 
visions for  the  nutrition  of  the  embryo  in  the  successive  phases  of  its  existence, 
and  the  adaptations  of  its  general  organization  to  each  respectively — constitutes 
one  of  the  most  interesting  departments  of  Physiological  Science,  and  one 
which  has  of  late  years  received  more  attention  than  any  other.  It  is  a  branch 
of  the  inquiry,  however,  which  has,  and  seems  likely  to  have  less  practical 
bearing  than  any  other ;  for  neither  as  regards  fhe  preservation  of  the  body  in 
health,  nor  in  its  restoration  from  disease,  is  it  easy  to  see  what  direct  benefit 
the  most  exact  knowledge  of  Embryonic  Development  is  likely  to  afford.  The 
chief  subject  on  which  it  throws  light,  is  that  of  Congenital  Malformations  and 
Deficiencies ;  many  of  which  are  now  distinctly  traceable  to  arrest  or  irregu- 
larity of  the  developmental  processes,  some  of  them,  indeed,  to  excess  (§  596). 
— For  these  reasons,  the  topic  before  us  will  be  passed  over  much  more  lightly 
in  the  present  Treatise  than  its  scientific  importance  might  seem  to  demand ; 
and  all  that  will  be  here  attempted,  will  be  a  mere  sketch  of  the  mode  in  which 
the  evolution  of  the  germ  takes  place,  this  being  followed  in  the  first  instance 
as  a  whole,  whilst  its  principal  organs  will  be  afterwards  separately  considered 
as  they  successively  present  themselves. 

993.  This  sketch,  however,  will  serve  to  convey  an  idea  of  the  nature  of  the 
process,  and  to  illustrate  its  conformity  in  Man  to  that  great  law  of  progress 
from  the  general  to  the  special,  which  is  equally  manifested  in  the  development 
of  every  other  organized  being.  For,  when  we  first  discern  the  primordial  cell 
which  is  to  evolve  itself  into  the  Human  organism,  we  can  trace  nothing  that 
essentially  distinguishes  it  from  that  which  might  give  origin  to  any  other  form 
of  organic  structure,  either  Vegetable  or  Animal ;  its  condition,  in  fact,  being 
permanently  represented  by  the  humblest  single  celled  Plants  and  Animals. 
The  earliest  stage  of  its  development  consists  in  simple  multiplication  by  dupli- 
cative  subdivision,  so  that  a  mass  of  cells  comes  to  be  produced,  amidst  the 
several  individuals  of  which  no  difference  can  be  traced ;  and  this  also  finds  its 
parallel  among  the  simpler  organisms  of  both  kingdoms.  Soon,  however,  this 
homogeneous  condition  gives  rise  to  a  heterogeneous  one ;  the  further  changes 
which  different  parts  of  the  mass  undergo  not  being  of  the  same  uniform  cha- 
racter, so  that  a  marking  out  of  organs,  or  instrumental  parts  adapted  for  differ- 
ent purposes  in  the  economy,  comes  to  be  discernible.  The  organs,  however, 
whose  distinctness  first  becomes  apparent,  are  not  usually  those  which  we  trace 
in  the  completed  structure,  but  have  a  merely  temporary  character ;  being 
evolved  either  as  a  sort  of  scaffolding  or  framework  for  the  building  up  of  the 
more  permanent  parts,  or  with  a  view  to  the  nutrition  of  the  embryo  during  the 
evolution  of  these.  Although  the  first  indications  of  heterogeneousness  in  the 
germinal  mass  are  of  nearly  the  same  kind  in  all  animals — consisting  in  the 
formation  of  a  Hastodermic  membrane  (composed,  however,  of  nothing  else  than 
layers  of  cells)  upon  its  exterior,  which  serves  as  a  sort  of  temporary  stomach, 
whilst  a  large  part  of  the  included  mass  undergoes  liquefaction,  and  serves  as 
the  nutrient  material  for  the  tissues  which  are  to  be  evolved  from  it — yet  indi- 
cations are  very  speedily  manifested,  of  the  primary  division  of  the  Animal 
Kingdom,  of  which  the  new  being  is  a  member  j — thus,  in  the  case  of  the  Hu- 
man embryo,  as  that  of  all  Vertebrated  animals,  the  first  indication  of  the  per- 
manent organization  is  shown  in  the  "  primitive  trace"  which  marks  out  the 
line  of  the  vertebral  column  (Plate  II.  Fig.  11)  ;  and  in  this  we  very  soon  dis- 
cern the  foundations  of  the  separate  vertebra  (Fig.  12,  c).  But  there  is  no- 
thing at  this  period  to  distinguish  the  germ  of  Man  from  that  of  any  other  Ver- 
tebrated animal,  this  early  part  of  the  developmental  process  being  carried  on 
upon  the  same  plan  in  every  member  of  that  sub-kingdom ;  and  it  is  not  until 
we  meet  with  indications  of  the  plans  which  are  peculiar  to  the  respective 


DEVELOPMENT   OP   THE   EMBRYO.  987 

classes  of  that  sub-kingdom,  that  we  can  discover  whether  the  germ  in  course  of 
evolution  is  to  become  a  Mammal,  Bird,  Reptile,  or  Fish.  So,  even  when  it 
has  been  recognized  as  belonging  to  the  Mammalian  class,  there  is,  at  first,  no- 
thing to  distinguish  it  from  that  of  any  other  Mammal ;  and  it  is  only  with 
the  advance  of  the  developmental  process  that  indications  successively  present 
themselves,  which  enable  us  to  distinguish,  one  after  another,  the  characters  of 
the  order,  the  family,  the  genus,  the  species,  the  variety,  the  sex,  and  the  indi- 
vidual— the  more  special  features  progressively  evolving  themselves  out  of  the  more 
general,  which  is  the  expression  of  the  law  of  development,  common  to  all  Or- 
ganized beings.1 

994.  With  this  progressive  alteration  in  the  condition  of  the  embryo  itself,  a 
very  remarkable  series  of  alterations  takes  place,  pari  passu,  in  the  mode  in 
which  it  is  supplied  with  nutrient  material,  and  in  the  provisions  for  the  aera- 
tion of  its  circulating  fluid. — The  first  evolution  of  the  germ  takes  place  en- 
tirely at  the  expense  of  the  yelk  ;  of  which,  however,  the  store  contained  in 
the  Mammalian  ovum  is  very  small.     The  whole  of  this  is  very  speedily  incor- 
porated in  the  substance  of  the  germ,  by  the  peculiar  process  to  be  presently 
described ;  and  there  is  no  residual  store  of  "  food-yelk/'  such  as  that  which, 
in  the  Bird,  serves  for  the  nutrition  of  the  embryo  during  the  whole  remainder 
of  the  developmental  process,  being  gradually  absorbed  into  the  substance  of 
the  blastodermic  membrane,  and  there  converted  into  blood.     The  Mammalian 
ovum,  however,  from  the  time  it  reaches  the  Uterus,  is  furnished  with  a  new 
supply  of  nourishment  in  the  fluid  secreted  by  the  Decidual  membrane  (§  977) ; 
and  for  the  absorption  of  this,  it  is  particularly  adapted  by  the  villosities  which 
develop  themselves  from  its  own  external  envelop.     These,  at  first  entirely  des- 
titute of  bloodvessels,  are  subsequently  penetrated  at  a  certain  part  of  the  sur- 
face by  the  fostal  capillaries  brought  to  them  by  an  organ,  the  Allantois,  which 
is  developed  in  Birds  as  the  temporary  instrument  of  respiration ;  and  thus  is 
originated  the  foetal  portion  of  the  Placenta,  of  whose  formation  details  will  be 
presently  given.     From  the  time  that  this  organ  is  completed,  up  to  the  birth 
of  the  Infant,  the  embryo  draws  its  nutrient  materials  direct  from  the  maternal 
blood,  though  not  receiving  that  blood  as  such  into  its  own  organism  ;  and  it  is 
through  the  same  medium  that  the  aeration  of  its  own  blood  is  effected,  its  pul- 
monary apparatus  being  as  yet  inoperative.     Its  circulating  system,  arranged  in 
accordance  with  these  requirements,  presents  many  peculiarities  which  mark  its 
fo3tal  character ;  and  the  alteration  in  the  course  of  the  blood,  which  takes  place 
as  soon  as  the  respiratory  organs  come  into  play,  constitutes  the  essential  differ- 
ence between  intra-uterine  and  extra-uterine  life.     If,  as  sometimes  happens, 
the  lungs  of  the  new-born  infant  expand  but  imperfectly  or  scarcely  at  all,  the 
circulation  continues  to  be  carried  on,  in  a  greater  or  less  degree,  upon  its  intra- 
uterine  plan ;  and  this,  when  the  placenta  is  no  longer  capable  of  supplying 
the  needed  aeration,  is  incompatible  with  the  persistence  of  life. 

995.  Our  knowledge  of  the  first  stages  of  the  developmental  process  in  the 
Mammalian  ovum  is  in  many  respects  incomplete  ;  and  it  is  requisite  to  inter- 
pret what  has  been  obscurely  seen  in  the  ova  of  this  class,  by  the  clearer  views 
derived  from  observation  of  those  of  the  lower  animals.3 — As  already  stated, 

1  See,  on  this  subject,  the  Author's  "Princ.  of  Phys.,  Gen.  and  Comp.,"  CHAPS,  vnr. 
and  xviii.,  Am.  Ed. ;  in  the  former  of  which  will  be  found  an  examination  of  the  commonly 
received  doctrine,  that  the  higher  forms  in  the  course  of  their  development  pass  through 
the  phases  which  remain  permanently  characteristic  of  the  lower. 

2  The  researches  of  Kolliker  ("  Muller's  Archiv.,"  1843,  p.  68),  and  Bagge  ("  DeEvolut. 
Strongyli  et  Ascarid.,  Diss.  Inaug.,"  1841)  on  the  ova  of  Entozoa — those  of  Mr.  Newport 
("Philos.  Transact.,"  1851)  on  the  ova  of  Batrachia,  and  those  of  Bischoff  ("Entwicke- 
lungsgeschichte  des  Hunde-eies,"  1845)  on  the  ova  of  the  Bitch — are  the  most  valuable 
which  we  at  present  possess. 


988 


OP   GENERATION. 


the  germinal  vesicle  disappears  at  or  about  the  time  of  fecundation  ;  but  its  dis- 
appearance is  not  a  result  of  fecundation,  since  it  also  takes  place  in  the  unim- 


Cleaving  of  the  yelk  after  fecundation :  A,  B,  c  (from  Kolliker),  ovum  of  Ascaris  nigrovenosa;  D  and  E,  that 
of  Ascaris  acuminata  (from  Bagge). 

pregnated  egg,  in  consequence  (it  may  be  presumed)  of  the  completion  of  its 
term  of  life,  and  of  those  operations  which  it  was  developed  to  perform.  Its 
place  is  seen  to  be  occupied  at  an  early  period  after  fecundation,  by  a  new  and  pe- 
culiar cell,  the  origin  of  which  is  obscure,  but  the  destination  of  which  is  most 
important ;  for  it  is  by  the  duplicative  subdivision  of  this  cell,  first  into  2,  then 

Fig.  261. 


A.  Ovum  of  a  Bitch,  from  the  Fallopian  tuhe,  half  an  inch  from  its  opening  into  the  uterus,  showing  the 
sona  pellucida  with  adherent  spermatozoids,  the  yelk  divided  into  its  first  two  segments,  and  two  small  gran- 
ules or  vesicles  contained  with  the  yelk  in  the  cavity  of  the  zona.  B.  Ovum  of  a  bitch  from  the  lower  ex- 
tremity of  the  Fallopian  tube :  the  cells  of  the  tunica  granulosa  have  disappeared :  the  yelk  is  divided  into 
four  segments,  c.  Ovum  of  bitch  from  the  lower  extremity  of  the  Fallopian  tube,  in  a  latter  stage  of  the 
division  of  the  yelk.  D.  An  ovum  from  the  uterus :  it  is  larger,  the  zona  thicker,  and  the  segments  of  the 
yelk  are  very  numerous.  E.  Ovum  from  the  lower  extremity  of  the  Fallopian  tube  burst  by  compression : 
the  segments  of  the  yelk  have  partly  escaped,  and  in  each  of  them  a  bright  spot  or  vesicle  is  visible. 

into  4,  then  into  8,  and  so  on,  and  by  the  metamorphoses  which  its  progeny 
undergo,  that  the  whole  embryonic  fabric  is  gradually  evolved.  Hence  this  cell 
may  be  termed  the  embryo-cell.1  At  the  same  time  a  peculiar  change  begins  to 

1  The  embryo- cell  has  not  yet  been  clearly  made  out  in  the  Mammalian  ovum ;  but  from 
the  conformity  of  the  subsequent  appearances  to  those  which  are  seen  in  the  ova  of  the 
lower  animals,  there  is  every  reason  to  believe  that  the  formation  of  either  a  complete  cell, 
or  of  a  nucleus  having  the  same  essential  endowments,  is  a  preliminary  to  the  cleavage  of 
the  yelk. 


DEVELOPMENT  OP  THE  EMBRYO.  989 

take  place  in  the  yelk,  the  whole  sphere  of  which  is  first  marked  out  by  a  fur- 
row into  two  hemispheres,  and  is  at  last  completely  divided  by  the  extension  of 
this  fission  to  the  centre ;  each  half  is  again  furrowed  and  then  cleft  in  the  same 
manner,  and  thus  the  entire  yelk  is  broken  up  into  a  mass  of  segments  (Fig. 
261,  A,  B,  c).  This  "  segmentation"  takes  place  pari  passu  with  the  multipli- 
cation of  the  embryo-cells,  each  of  which  is  surrounded  by  a  distinct  portion  of 
the  yelk  ;  and  there  seems  every  probability  that  it  is  determined  by  that  mul- 
tiplication, and  that  each  cell  of  the  pair  that  is  formed  by  the  duplicative  sub- 
division of  its  predecessor  draws  around  itself  its  proper  share  of  the  nutritive 
material. — These  changes  take  place  in  the  Mammalian  Ovum,  during  its 
transit  along  the  Fallopian  tube  to  the  uterus  ;  so  that,  by  the  time  of  its  arrival 
there,  the  whole  cavity  of  the  Zona  pellucida  is  occupied  by  minute  spherules 
of  yelk,  each  containing  a  transparent  vesicle,1  the  aggregation  of  which  gives 
it  a  mulberry-like  aspect  (Fig.  261,  D)  ;  and  by  a  continuance  of  the  same  pro- 
cess o"f  subdivision,  the  component  segments  becoming  more  and  more  minute, 
the  mass  comes  to  present  a  finely  granular  aspect. 

996.  At  this  stage  it  does  not  appear  that  the  several  segments  of  the  yelk 
have  a  distinct  enveloping  membrane ;  but  an  envelop  is  now  formed  around 
each  of  them,  converting  it  into  a  cell,  of  which  the  included  vesicle  constitutes 
the  nucleus,  and  of  which  the  portion  of  the  yelk  surrounding  this  forms  the 
contents.  This  happens  first  to  the  peripheral  portions  of  the  mass  ;  and  as  its 
cells  are  fully  developed,  they  arrange  themselves  at  the  surface  of  the  yelk 
into  a  kind  of  membrane,  and  at  the  same  time  assume  a  pentagonal  or  hexa- 
gonal shape  from  mutual  pressure,  so  as  to  resemble  pavement-epithelium 
(Plate  I.  Fig  5).  As  the  globular  masses  of  the  interior  are  gradually  con- 
verted into  cells,  they  also  pass  to  the  surface  and  accumulate  there,  thus  in- 
creasing the  thickness  of  the  membrane  already  formed  by  the  more  superficial 
layer  of  cells,  while  the  central  part  of  the  yelk  remains  filled  only  with  a  clear 
fluid.  By  this  means  the  exterior  of  the  yelk  is  speedily  converted  into  a  kind 
of  secondary  vesicle  situated  within  the  Zona  pellucida,  and  named  by  Bischoff 
the  Uastodermic  vesicle.  This  vesicle,  very  soon  after  its  formation,  presents  at 
one  point  an  opaque,  roundish  spot  (Plate  I.  Fig.  6),  which  is  produced  by  an 
accumulation  of  cells  and  nuclei  of  less  transparency  than  elsewhere ;  this  is 
termed  the  area  germinativa.  The  wall  of  the  vesicle,  which  is  termed  the 
germinal  membrane,  increases  in  extent  and  thickness  by  the  formation  of  new 
cells  (whose  mode  of  production  has  not  been  clearly  made  out) ,  and  it  sub- 
divides into  two  layers  (Plate  I.  Fig.  7),  which,  although  both  at  first  composed 
of  cells,  soon  present  distinctive  characters,  and  are  concerned  in  very  different 
ulterior  operations.  The  outer  one  of  these  is  commonly  known  as  the  serous 
layer  (Fig.  8)  ;  but  being  the  one  in  whose  substance  the  foundation  is  laid  for 
the  vertebral  column  and  the  nervous  system,  it  is  sometimes  called  the  animal 
layer.  The  inner  one  is  usually  known  as  the  mucous  layer  (Fig.  9) ;  and 
being  the  one  chiefly  concerned  in  the  formation  of  the  nutritive  apparatus,  it 
is  sometimes  called  the  vegetative  layer.  This  division  is  at  first  most  evident 
in  the  neighborhood  of  the  area  germinativa ;  but  it  soon  extends  from  this 
point,  and  implicates  nearly  the  whole  of  the  germinal  membrane. 

997.  The  Area  Germinativa,  at  its  first  appearance,  has  a  rounded  form;  but 
it  soon  loses  this,  becoming  first  oval,  and  then  pear-shaped  (Plate  II.  Fig.  11). 
While  this  change  is  taking  place  in  it,  there  gradually  appears  in  its  centre  a 
clear  space,  termed  the  area  pellucida  (a) ;  and  this  is  bounded  externally  by  a 

1  This  vesicle  has  not  yet  been  made  out,  in  the  Mammalian  ovum,  to  be  a  true  cell, 
which  it  certainly  is  in  the  ovum  of  many  of  the  lower  animals  ;  its  appearance,  when 
liberated  from  the  yelk- granules  which  surround  it,  being  rather  that  of  a  fat  or  oil- 
globule. 


990  OF  GENERATION. 

more  opaque  circle  (whose  opacity  is  due  to  the  greater  accumulation  of  cells 
and  nuclei  in  that  part  than  in  the  area  pellucida),  which  subsequently  becomes 
the  area  vasculosa.  In  the  formation  of  these  two  spaces,  both  the  serous  and 
mucous  layers  of  the  germinal  membrane  seem  to  take  their  share ;  but  the 
foundation  of  the  embryonic  structure,  known  as  the  primitive  trace,  is  laid  in 
the  serous  lamina  only.  This  consists  in  a  shallow  groove  (c),  lying  between 
two  oval  masses  (6),  known  as  the  laminae  dorsales.  The  form  of  these 
changes  with  that  of  the  area  pellucida ;  at  first  they  are  oval,  then  pyriform, 
and  at  last  become  of  a  guitar-shape.  At  the  same  time,  they  rise  more 
and  more  from  the  surface  of  the  area  pellucida,  so  as  to  form  two  ridges  of 
higher  elevation,  with  a  deeper  groove  between  them  ;  and  the  summits  of  these 
ridges  tend  to  approach  each  other,  and  gradually  unite,  so  as  to  convert  the 
groove  into  a  tube.  At  the  same  time,  the  anterior  portion  of  the  groove 
dilates  into  three  recesses  or  vesicles  (Plate  II.  Fig.  12,  6),  which  indicate  the 
position  of  the  three  principal  divisions  of  the  Encephalon,  afterwards  to  Tbe  de- 
veloped as  iheprosencephalon,  the  mesencephalon,  and  the  epencephalon  (§  1012). 
The  most  internal  parts  of  these  laminae,  bounding  the  bottom  and  sides  of  the 
groove,  appear  to  furnish  the  rudiments  of  the  nervous  centres  which  this  cranio- 
vertebral  canal  is  to  contain ;  whilst  the  outer  parts  are  developed  into  the  rudi- 
ments of  the  vertebral  column  and  cranium.  Even  before  the  laminae  dorsales 
have  closed  over  the  primitive  groove,  a  few  square-shaped  and  at  first  indistinct 
plates,  which  are  the  rudiments  of  vertebrae  (c),  begin  to  appear  at  about  the 
middle  of  each.  The  position  of  the  bodies  of  the  vertebrae  is  indicated  at  this 
period,  in  the  embryos  of  Birds  and  Fishes,  by  a  distinct  cylindrical  rod  of 
nucleated  cells,  termed  the  chorda  dorsalis;  and  this  retains  its  embryonic  type 
in  the  Myxinoid  Fishes  (§  1010).  While  this  is  going  on,  an  accumulation  of 
cells  takes  place  between  the  two  laminae  of  the  germinal  membrane  at  the  "area 
vasculosa ;"  and  these  cells  speedily  form  themselves  into  a  distinct  layer,  the 
vascular  lamina,  in  which  the  first  bloodvessels  of  the  embryo  are  developed, 
as  will  be  presently  described  (§  998).  From  the  dorsal  laminae  on  either  side, 
a  prolongation  passes  outwards  and  then  downwards,  forming  what  is  known  as 
the  ventral  lamina;  in  this  are  developed  the  ribs  and  the  transverse  processes 
of  the  vertebrae ;  and  the  two  have  the  same  tendency  to  meet  on  the  median 
line,  and  thus  to  close  in  the  abdominal  cavity,  which  the  dorsal  laminae  have  to 
inclose  the  spinal  cord.  At  the  same  time,  the  layers  of  the  germinal  mem- 
brane which  lie  beyond  the  extremities  of  the  embryo^  are  folded  in,  so  as  to 
make  a  depression  on  the  yelk ;  and  their  folded  margins  gradually  approach  one 
another  under  the  abdomen.  The  first  rudiment  of  the  intestinal  canal  presents 
itself  as  a  channel  along  the  under  surface  of  the  embryonic  mass,  formed  by 
the  rising  up  of  the  inner  layer  of  the  germinal  membrane  into  a  ridge  on  either 
side.  The  two  ridges  gradually  arch  over  and  meet,  so  as  to  form  a  tube,  which 
is  thus  (so  to  speak)  pinched  off  the  general  vitelline  sac ;  and  it  remains  in 
connection  with  this,  by  means  of  an  unclosed  portion,  which  constitutes  the 
"  vitelline  duct"  (Figs.  262,  263). 

998.  Whilst  these  new  structures  are  being  produced,  a  very  remarkable 
change  is  taking  place  in  tnat  part  of  the  serous  lamina  which  surrounds  the 
area  pellucida.  This  rises  up  on  either  side  in  two  folds;  and  these  gradually 
approach  one  another,  at  last  meeting  in  the  space  between  the  general  envelop 
and  the  embryo,  and  thus  forming  an  additional  investment  to  the  latter.  As 
each  fold  contains  two  layers  of  membrane,  a  double  envelop  is  thus  formed ; 
of  this,  the  outer  lamina  adheres  to  the  general  envelop ;  whilst  the  inner  re- 
mains as  a  distinct  sac,  to  which  the  name  of  Amnion  is  given.  (See  Figs.  264, 
265,  and  266.)  This  takes  place  during  the  third  day  in  the  Chick;  the  period 
at  which  it  occurs  in  the  Human  Ovum  is  difficult  to  be  ascertained,  owing  to 
the  small  number  of  normal  specimens  which  have  come  under  observation  at  a 


DEVELOPMENT   OP   THE   EMBRYO.  991 

sufficiently  early  stage. — During  the  same  period,  a  very  important  provision  for 
the  future  support  of  the  embryo  begins  to  be  made,  by  the  development  of 
bloodvessels  and  the  formation  of  blood.  Hitherto,  the  embryonic  structure 
has  been  nourished  by  direct  absorption  of  the  alimentary  materials  supplied  to 

Fig.  262.  Fig.  263. 


Plan  of  early  Uterine  Ovum.    Within  the  Diagram  of  Ovum  at  the  commencement  of  the  for- 

external  ring,  or  zona  pellucida,  are  the  mation  of  the  Amnion:  a,  chorion;   b,  yelk-sac;  c, 

serous  lamina,  a ;  the  yelk,  b ;  and  the  in-  embryo ;  d,  and  e,  folds  of  the  serous  layer  rising  up  to 

cipient  embryo,  c.  form  the  amnion. 

it  by  the  yelk ;  but  its  increasing  size,  and  the  necessity  for  a  more  free  com- 
munication between  its  parts  than  any  structure  consisting  of  cells  alone  can 
permit,  call  for  the  development  of  vessels  through  which  the  nutritious  fluid 
may  be  conveyed.  These  vessels  are  first  seen  in  that  part  of  the  Vascular  lamina 
of  the  germinal  membrane  (§  294)  which  immediately  surrounds  the  embryo; 
and  they  form  a  network,  bounded  by  a  circular  channel,  which  is  known  under 
the  name  of  the  Vascular  Area  (Plate  II.  Fig.  13).  This  gradually  extends 
itself,  until  the  vessels  spread  over  the  whole  of  the  membrane  that  contains  the 
yelk.  The  first  blood-disks  appear  to  be  formed  from  the  nuclei  of  the  cells, 
whose  cavities  have  become  continuous  with  each  other  to  form  the  vessels 
(§  149)  j  and  from  these,  the  subsequent  blood-disks  of  the  first  series  are  pro- 
bably generated.  This  network  of  bloodvessels  serves  the  purpose  of  absorbing 
the  nutritious  matter  of  the  yelk,  and  of  conveying  it  towards  the  embryonic 
structures,  which  are  now  in  process  of  rapid  development.  The  first  movement 
of  the  fluid  is  towards  the  embryo ;  and  this  can  be  witnessed  before  any  distinct 
heart  is  evolved.  The  same  process  of  absorption  from  the  yelk,  and  of  con- 
version into  blood,  probably  continues  as  long  as  there  is  any  alimentary  mate- 
rial left  in  the  sac. 

999.  The  Yelk-sac  is  early  separated  in  the  Mammalia,  by  a  constriction  of 
the  portion  which  is  continuous  with  the  abdomen  of  the  Embryo ;  and  it  is 
known  from  that  time  under  the  name  of  the  Umbilical  Vesicle  (Plate  I.  Fig. 
10,  i).  The  communication,  however,  remains  open  for  a  time  through  the 
vitelline  duct ;  and  even  after  this  has  been  cut  off,  the  trunks  which  connect 
the  circulating  system  of  the  embryo  with  that  of  the  vascular  area  are  discern- 
ible ;  these  are  called  Omphalo-Mesenteric,  Meseraic,  or  Vitelline  vessels  (Figs. 
266,  267,  q,  r).  It  was  formerly  believed  that  the  nutrient  matter  of  the  yelk 
passes  directly  through  the  vitelline  duct  into  the  (future)  digestive  ^cavity  of 
the  embryo,  and  is  from  it  absorbed  into  its  structure ;  but  there  can  now  be 
little  doubt,  that  the  vitelline  vessels  are  the  real  agents  of  its  absorption,  and 
that  they  convey  it,  through  the  general  circulating  system,  to  the  tissues  in 
process  of  formation.  They  correspond,  in  fact,  to  the  Mesenteric  veins  of  In- 
vertebrated  animals,  which  are  the  sole  agents  in  the  absorption  of  nutriment 
from  their  digestive  cavity  (§  459) ;  and  the  blastodermic  vesicle  is  to  be  regarded 


992  OF   GENERATION- 

as  the  temporary  stomach  of  the  embryo — remaining  as  the  permanent  stomach 
in  the  Radiated  tribes.1 

1000.  The  formation  of  the  Heart,  which  is  the  first  of  the  permanent  organs 
of  the  Embryo  that  comes  into  functional  activity,  takes  place  in  the  substance 
of  the  vascular  layer,  beneath  the  upper  part  of  the  spinal  column.     Its  first 
rudiment  consists  of  an  aggregation  of  cells,  of  which  the  inner  part  break  down 
to  form  its  cavity,  whilst  the  outer  remain  to  constitute  its  walls.     For  a  long 
time  after  it  has  distinctly  commenced  pulsating,  and  is  obviously  exerting  a 
contractile  force,  its  walls  obviously  retain  the  cellular  character,  and  only  be- 
come muscular  by  a  progressive  histological  transformation  (§  310).     The  first 
appearance  of  the  Heart  in  the  Chick  is  at  about  the  27th  hour  ;  the  time  of  its 
formation  in  Mammalia  has  not  been  distinctly  ascertained.     In  its  earliest  form 
it  has  the  same  simple  character  which  is  presented  by  the  central  impelling 
cavity  of  the  lower  Invertebrata ;  being  a  mere  prolonged  canal,  which  at  its 
posterior  extremity  receives  the  veins,  and  at  its  anterior  sends  forth  the  arteries. 
After  a  short  time,  however,  it  becomes  bent  upon  itself  (Plate  II.  Fig.  13,  d)j 
and  it  is  soon  subdivided  into  three  cavities,  which  exist  in  all  Vertebrata,  viz., 
a  simple  auricle  or  receiving  cavity,  a  simple  ventricle  or  propelling  cavity,  and 
a  bulbus  arteriosus  at  the  origin  of  the  aorta.     The  circulation  is  at  first  carried 
on  exactly  upon  the  plan  which  is  permanently  exhibited  by  Fishes.     The  Aorta 
subdivides  into  four  or  five  arches  on  either  side  of  the  neck  (Figs.  266,  267,  e, 
ef,  e"),  which  are  separated  by  fissures  much  resembling  those  forming  the  en- 
trances to  the  gill-cavities  of  Cartilaginous  Fishes ;  and  these  arches  reunite  to 
form  the  descending  aorta,  which  transmits  branches  to  all  parts  of  the  body. — 
Such  is  the  first  phase  or  aspect  of  the  Circulating  Apparatus,  which  is  common 
to  all  Vertebrata  during  the  earliest  period  of  their  development,  and  which  may 
therefore  be  considered  as  its  most  general  form.     It  remains  permanent  in  the 
class  of  Fishes  ;  and  in  them  the  vascular  system  undergoes  further  development 
on  the  same  type,  a  number  of  minute  tufts  being  sent  forth  from  each  of  the 
arches,  which  enter  the  filaments  of  the  gills,  and  serve  for  the  aeration  of  the 
blood.     In  higher  Vertebrata,  however,  the  plan  of  the  circulation  is  afterwards 
entirely  changed,  by  the  formation  of  new  cavities  in  the  heart,  and  by  the  pro- 
duction of  new  vessels ;  these  changes  will  be  presently  described.     It  is  in- 
correct, therefore,  to  speak  of  the  vascular  arches  in  their  necks  as  branchial 
arches ;  since  no  branchiae  or  gills  are  ever  developed  from  them.     The  clefts 
between  them  may  be  very  distinctly  seen  in  the  Human  Foatus  towards  the 
end  of  the  first  month ;  during  the  second,  they  usually  close  up  and  disappear. 

1001.  With  the  evolution   of  a  Circulating  apparatus,  adapted  to  absorb 
nourishment  from  the  store  prepared  for  the  use  of  the  Embryo,  and  to  convey 
it  to  its  different  tissues,  it  becomes  necessary  that  a  Respiratory  apparatus 
should  also  be  provided,  for  depurating  the  blood  from  the  carbonic  acid  with 

1  Previously  to  the  ninth  day  of  incubation  (in  the  Fowl's  egg),  a  series  of  folds  are 
formed  by  the  lining  membrane  of  the  yelk-bag,  which  project  into  its  cavity  ;  these  become 
gradually  deeper  and  more  crowded,  as  the  bag  diminishes  in  size  by  the  absorption  of 
its  contents.  The  vitelline  vessels  that  ramify  upon  the  yelk-bag  send  into  these  folds 
(or  valvulae  conniventes)  a  series  of  inosculating  loops,  which  immensely  increase  the  ex- 
tent of  this  absorbing  apparatus.  But  these  minute  vessels  are  not  in  immediate  contact 
with  the  yelk ;  for  there  intervenes  between  them  (as  was  first  noticed  by  Mr.  Dalrymple) 
a  layer  of  nucleated  cells,  which  is  easily  washed  away.  (See  Dr.  Baly's  Translation  of 
"  M  tiller's  Physiology,"  pp.  1557-1559.)  It  was  from  the  color  of  these,  communicated 
to  the  vessels  beneath,  that  Haller  termed  the  latter  vasa  lutea  ;  when  the  layer  is  removed, 
the  vessels  present  their  usual  color.  There  seems  good  reason  to  believe  that  these 
cells,  like  those  of  the  Intestinal  Villi  in  the  adult  ($  461),  are  the  real  agents  in  the  pro- 
cess of  absorbing  and  assimilating  the  nutritive  matter  of  the  yelk  ;  and  that  they  deliver 
this  up  to  the  vessels,  by  themselves  undergoing  rupture  or  dissolution,  being  replaced  by 
new  layers. 


DEVELOPMENT   OF   THE   EMBRYO. 


993 


which  it  becomes  charged  during  the  course  of  its  circulation.  The  temporary 
Respiratory  apparatus  now  to  be  described  bears  a  strong  resemblance  in  its 
own  character,  and  especially  in  its  vascular  connections,  to  the  gills  of  the 
Mollusca,  which  are  prolongations  of  the  external  surface  (usually  near  the 
termination  of  the  intestinal  canal),  and  which  almost  invariably  receive  their 
vessels  from  that  part  of  the  system.  This  apparatus,  which  is  termed  the 
Allantois,  sprouts  forth  from  the  caudal  extremity  of  the  embryo  at  first  as  a 
little  mass  of  cells,  which  soon  exhibits  a  cavity  (probably  formed  by  the  lique- 
faction of  the  cells  of  the  internal  part),  so  that  a  vesicle  is  formed  (Figs.  264, 
265,  </),  which  looks  like  a  diverticulum  from  the  lower  part  of  the  digestive 


Fig.  265. 


Diagram  of  an  early  Human  Ovum,  with  the 
Amnion  in  process  of  formation :  a,  the  chorion ; 
b,  the  vitelline  mass,  surrounded  by  the  blasto- 
dermic  vehicle ;  c,  the  embryo ;  d,  e,  and  /,  ex- 
ternal and  internal  folds  of  the  serous  layer, 
forming  the  amnion ;  g,  incipient  allantois. 


Diagram  representing  a  Human  Ovum  in  second 
month:  a  1,  smooth  portion  of  chorion;  a  2, 
villous  portion  of  chorion ;  k,  k,  elongated  villi, 
beginning  to  collect  into  Placenta ;  6,  vitelline  or 
umbilical  .vesicle ;  c,  embryo ;  /,  amnion  (inner 
layer);  g,  allantois;  h,  outer  layer  of  amnion, 
coalescing  with  chorion. 


cavity.  This  vesicle,  in  Birds,  soon  becomes  so  large  as  to  extend  itself  around 
the  whole  yelk-sac,  intervening  between  it  and  the  membrane  of  the  shell,  and 
coming  through  the  latter  into  relation  with  the  external  air ;  but  in  the  em- 
bryos of  Mammalia,  being  early  superseded  by  another  provision  for  the  aeration 
of  the  blood,  the  allantois  seldom  attains  any  considerable  dimensions.  Its 
chief  office  in  them  is  to  convey  the  vessels  of  the  embryo  to  the  chorion ;  and 
its  extent  bears  a  pretty  close  correspondence  with  the  extent  of  surface  through 
which  the  chorion  comes  into  vascular  connection  with  the  decidua.  Thus,  in 
the  Carnivora,  whose  placenta  extends  like  a  band  around  the  whole  ovum,  the 
allantois  also  lines  nearly  the  whole  inner  surface  of  the  chorion ;  on  the  other 
hand,  in  Man  and  the  Quadrumana,  whose  placenta  is  restricted  to  one  spot, 
the  allantois  is  small,  and  conveys  the  foetal  vessels  to  one  portion  only  of  the 
chorion.  When  these  vessels  have  reached  the  chorion,  they  ramify  in  its 
substance,  and  send  filaments  into  its  villi ;  and  in  proportion  as  these  villi  form 
that  connection  with  the  uterine  structure  which  has  been  already  described 
(§§  977-982),  do  the  vessels  increase  in  size.  They  then  pass  directly  from 
the  foetus  to  the  chorion ;  and  the  allantois,  being  no  longer  of  any  use,  shrivels 
up ;  and  remains  as  a  minute  vesicle,  only  to  be  detected  by  careful  examina- 
tion. The  same  thing  happens  in  regard  to  the  umbilical  vesicle,  from  which 
the  entire  contents  have  been  by  this  time  withdrawn ;  and  from  henceforth  the 
foetus  is  completely  dependent  for  the  materials  of  its  growth  upon  the  supply  it 
63 


994 


OF   GENERATION. 


receives  through  the  placenta,  which  is  conducted  to  it  by  the  vessels  of  the 
umbilical  cord.  This  state  of  things  is  represented  in  Figs.  266.  267,  n  n',  o  o'. 
— The  allantois  has  a  correspondence  in  origin  with  the  Urinary  Bladder ;  but 
it  is  only  the  lowest  part  of  it,  pinched  off  as  it  were,  from  the  rest,  which  re- 
mains as  such.  The  duct  by  which  it  is  connected  with  the  abdomen  gradually 
shrivels  ;  and  a  vestige  of  this  is  permanent,  forming  the  Urachus  or  suspensory 
ligament  of  the  Bladder  by  which  it  is  connected  with  the  Umbilicus.  Before 
this  takes  place,  however,  the  Allantois  is  the  receptacle  for  the  secretion  of 
the  Corpora  Wolffiana,  and  of  the  true  Kidneys,  when  they  are  formed  (§  1007). 
1002.  It  will  be  seen,  from  the  succeeding  diagram,  that  the  Umbilical  Cord 
receives  an  investment  from  the  Amnion,  which  forms  a  kind  of  tubular  sheath 
around  it;  it  is  continuous  at  the  umbilicus  with  the  integument  of  the  foetus; 
and  at  the  point  where  the  cord  enters  the  placenta,  it  is  reflected  over  its  in- 
ternal or  fcetal  surface.  The  Amnion  (which  thus  forms  a  shut  sac,  like  that 


Fig.  266. 


Fig.  267. 


Diagram  of  the  Circulation  in  the  Human  Embryo  and  its  Appendages,  as  seen  The  game,  as  seen 

in  profile  from  the  right  side,  at  the  commencement  of  the  formation  of  the  Pla-  from  the  front, 

centa:  a,  venous  sinus  receiving  all  the  systemic  veins ;  5,  right  auricle;  I/,  left 
auricle  :  c,  right  ventricle ;  d,  bulbus  aorticus,  subdividing  into  e,  e',  e",  branchial 
arteries;/,  arterial  trunk  formed  by  their  confluence ;  g,  vena  azygos  superior ;  h, 
confluence  of  the  superior  and  inferior  azygos ;  j,  vena  cava  inferior ;  k,  vena  azy- 
gos inferior;  m,  descending  aorta;  n,  n,  umbilical  arteries  proceeding  from  it;  o, 
umbilical  vein ;  q,  omphalo-mesenteric  vein ;  r,  omphalo-mesenteric  artery,  dis- 
tributed on  the  walls  of  the  vitelline  vesicle  t ;  v,  ductus  venosus ;  y,  vitelline 
duct ;  z,  chorion. 

of  the  pleura,  arachnoid,  &c.)  contains  a  fluid  known  as  the  liquor  amnii;  this 
consists  of  water  holding  in  solution  a  small  quantity  of  albumen  and  saline 
matter,  and  resembling,  therefore,  very  diluted  serum.  During  the  first  two 
months  of  gestation,  the  amnion  and  the  inner  lining  of  the  chorion  (which  is 


DEVELOPMENT    OP   THE   EMBRYO.  995 

really  the  reflected  layer  of  the  amnion,  just  as  the  lining  of  the  abdominal 
cavity  is  formed  by  the  peritoneum)  are  separated  by  a  gelatinous-looking  sub- 
stance, which  probably  aids  in  the  nutrition  of  the  embryo  previously  to  the 
formation  of  the  placenta.  This  is  absorbed  during  the  second  month ;  and 
the  amnion  is  then  found  immediately  beneath  the  chorion. — In  the  Umbilical 
Cord,  when  it  is  completely  formed,  the  following  parts  may  be  traced :  1. 
The  tubular  sheath  afforded  by  the  Amnion.  2.  The  Umbilical  Vesicle  (Fig. 
266,  0,  with  its  pedicle,  or  vitelline  duct.  3.  The  Vasa  Omphalo-Meseraica 
(q_j  r),  or  mesenteric  vessels  of  the  embryo,  by  which  the  yelk  was  absorbed 
into  its  body ;  these  accompany  the  pedicle.  4.  The  Urachus,  and  remains  of 
the  Allantois.  5.  The  Vasa  Umbilicalia  (nn,  o),  which,  in  the  later  period  of 
gestation,  constitute  the  chief  part  of  the  Cord.  These  last  vessels  consist  in 
Man  of  two  arteries  and  one  vein.  The  arteries  are  the  main  branches  of  the 
Hypogastric ;  and  they  convey  to  the  placenta  the  blood  which  has  to  be  aerated 
and  otherwise  revivified,  by  being  brought  into  relation  with  that  of  the  mother. 
The  vein  returns  this  to  the  foetus,  and  discharges  a  part  of  it  into  the  Vena 
Portse,  and  a  part  directly  through  the  Ductus  Venosus  into  the  Vena  Cava. 

1003.  A  change  in  the  type  of  the  Circulating  system  of  the  foetus,  from 
that  at  first  presented  by  it  (§  1000),  takes  place  at  a  very  early  period.  At 
about  the  4th  week,  in  the  Human  Embryo,  a  septum  begins  to  be  formed  in 
the  ventricle;  and  by  the  end  of  the  8th  week  it  is  complete.  The  septum 
auriculorum  is  formed  at  a  somewhat  later  period,  and  it  remains  incomplete 
during  the  whole  of  foetal  life ;  it  is  partly  closed  by  the  valvular  fold  covering 
the  foramen  ovale,  which  fold  is  developed  in  the  3d  month.  During  the  same 
period,  a  transformation  takes  place  in  the  arrangement  of  the  large  vessels 
proceeding  from  the  heart;  which  ends  in  their  assumption  of  the  form  they 
present  until  the  end  of  Foetal  life ;  and  this  undergoes  but  a  slight  alteration, 
when  the  plan  of  the  circulation  is  changed  at  the  moment  of  the  first  inspiration. 
The  number  of  aortic  arches  on  each  side,  which  was  five  at  first,  soon  becomes 
reduced  in  the  Mammalia  to  three,  by  the  obliteration  of  the  two  highest  pairs. 
The  "  bulbus  aorticus"  is  subdivided,  by  the  adhesion  of  its  walls  at  opposite 
points,  into  two  tubes,  of  which  one  becomes  the  Aorta  and  the  other  the 
Pulmonary  Artery :  and  of  the  three  pairs  of  (branchial)  arches,  the  highest, 
being  connected  with  the  aortic  trunk,  contributes  to  the  formation  of  the  Sub- 
clavian  and  Carotid  arteries ;  whilst  of  the  middle  pair,  the  arch  on  the  right 
side  is  obliterated,  and  the  other  becomes  the  "arch  of  the  aorta."  The  lowest 
pair  arises  from  the  Pulmonary  trunk,  and  forms  the  right  and  left  Pulmonary 
arteries;  that  on  the  left  side,  however,  goes  on  to  join  the  descending  aorta  as 
before,  and  thus  constitutes  the  Ductus  Arteriosus.  A  knowledge  of  these 
different  stages  in  the  development  of  the  Heart  and  Arterial  system  enables  us 
to  explain  many  of  the  malformations  which  they  occasionally  present  in  Man; 
these  being  for  the  most  part  due  to  arrest  of  development,  whereby  the  circu- 
lating apparatus  is  permanently  fixed  in  conditions  that  are  properly  characteristic 
of  cold-blooded  animals.  And  it  is  interesting  to  remark,  too,  that  the  varieties 
which  not  unfrequently  present  themselves  in  the  arrangement  of  the  principal 
trunks,  given  off  from  the  Aorta,  find  their  analogues  in  the  arrangements  that 
are  normally  characteristic  of  some  or  other  of  the  Mammalia.1 — The  Venous 
system  undergoes  changes  which  are  even  more  remarkable  than  those  of  the 
arterial  trunks.  In  its  earliest  condition,  it  has  been  ascertained  by  Rathke3  to 
present  essentially  the  same  type  in  the  embryos  of  all  Vertebrated  animals, 
the  peculiarities  of  each  group  being  acquired  by  a  process  of  subsequent  trans- 
formation. There  is  at  first  a  pair  of  anterior  venous  trunks  (Figs.  266,  267, 

1  See  "Princ.  of  Phys.,  Gen.  and  Comp.,"  Am.  Ed.,  $  491,  492. 

2  "  Ueber  den  Bau  und  die  Entwickelung  des  Venensystems  der  Wirbelthiere,"  1838. 


996  OF   GENERATION. 

</,  </),  receiving  the  blood  from  the  head,  and  a  pair  of  posterior  trunks  (&,  &'), 
formed  by  the  confluence  of  the  veins  of  the  trunk,  Wolffian  bodies,  &c. ;  the 
former  are  persistent  as  the  jugular  veins ;  the  latter  remain  separate  in  most 
Fishes,  where  they  are  designated  the  cardinal  veins;  but  in  Man  (as  in  warm- 
blooded Vertebrata  generally)  they  are  only  represented  by  the  venae  azygos, 
major  and  minor,1  which  coalesce  into  a  common  trunk  for  a  considerable  part 
of  their  length.  One  of  the  anterior  trunks  and  one  of  the  posterior  unite  on 
either  side,  to  form  a  canal  which  is  known  as  the  Ductus  Cuvieri ;  and  the 
ducts  of  the  two  sides  coalesce  to  form  a  shorter  main  canal,  which  enters  the 
auricle,  at  that  time  an  undivided  cavity.  This  common  canal  is  absorbed  into 
the  auricle  at  an  early  period,  in  all  Vertebrata  above  Fishes;  and  after  the 
septum  auriculorum  is  formed,  the  two  Cuvierian  ducts  separately  enter  the  right 
auricle.  This  arrangement  is  persistent  in  Birds  and  the  inferior  Mammals,  in 
which  we  find  two  Venae  Cavae  superiores,  entering  the  right  auricle  separately ; 
but  in  the  higher  Mammalia  and  in  Man,  the  left  duct  is  obliterated  and  the 
right  alone  remains  as  the  single  Vena  Cava  superior,  a  transverse  communicating 
branch  being  formed,  to  bring  to  it  the  blood  of  the  left  side.3  The  double 
Vena  Cava  sometimes  presents  itself  as  a  monstrosity  in  the  Human  subject. 
As  the  anterior  extremities  are  developed,  the  subclavian  veins  are  formed  to 
return  the  blood  from  them;  and  these  discharge  themselves  into  the  jugulars. 
The  Omphalo-Mesenteric  vein  (§  999),  which  is  another  primitive  trunk  common 
to  all  Vertebrata,  is  formed  by  the  confluence  of  the  veins  of  the  yelk-bag  and 
intestinal  canal,  and  passes  by  itself,  with  the  two  Cuvierian  ducts,  into  the 
auricle.  The  upper  part  of  this  remains  to  constitute  the  upper  part  of  the 
Inferior  Cava  (Figs.  266,  267,  j),  the  lower  portion  of  which  arises  between,  the 
Wolffian  bodies,  and  originally  enters  the  omphalo-mesenteric  vein  above  the 
liver.  When  the  liver  is  formed,  the  omphalo-mesenteric  vein  becomes  connected 
with  it  both  by  afferent  and  by  efferent  trunks,  the  former  remaining  as  the 
Vena  Portae,  and  the  latter  as  the  Hepatic  vein ;  and  after  giving  off  the  former 
trunks,  the  omphalo-mesenteric  vein  is  itself  obliterated,  so  that  all  the  blood 
which  it  conveys  passes  through  the  liver.  The  Inferior  Cava,  which  receives 
the  hepatic  vein,  is  gradually  enlarged  by  the  reception  of  most  of  the  veins 
from  the  inferior  part  of  the  trunk  and  the  lower  extremities,  and  the  vena 
azygos  is  reduced  in  the  same  proportion ;  in  some  rare  cases  of  abnormal  forma- 
tion, however,  the  vena  cava  fails  to  be  developed,  and  then  the  blood  from  the 
lower  parts  of  the  body  is  conveyed  to  the  superior  cava  through  the  system  of 
the  vena  azygos.  The  Umbilical  Vein  is  to  be  regarded  as  a  product  of  the 
combination  of  the  veins  of  the  allantois  with  an  anterior  vein  of  the  abdominal 
parietes;  it  being  probably  through  this  latter  channel  that  it  comes  to  discharge 
itself  into  the  vena  portae,  which  lies  in  a  part  of  the  body  very  distant  from 
that  at  which  the  allantois  was  developed.  As  the  omphalo-mesenteric  vein 
diminishes  in  size,  the  umbilical  vein  increases,  becoming  the  chief  source  of 
supply  to  the  vena  portae ;  and  it  also  forms  an  anastomosis  with  the  inferior 
cava,  which  constitutes  the  Ductus  Venosus. 

1004.  The  following  is  the  course  of  the  Circulation  in  the  mature  Fretus : 
The  fluid  brought  from  the  placenta  by  the  umbilical  vein  is  partly  conveyed  at 
once  to  the  ascending  Cava  by  means  of  the  ductus  venosus,  and  partly  flows 
through  the  vena  portae  into  the  liver,  whence  it  reaches  the  ascending  Cava  by 
the  hepatic  vein.  Having  thus  been  transmitted  through  the  two  great  depu- 

1  See  Miiller's  "  Verleichende  Anatomic  der  Myxinoiden,"  Berlin,  1840. 

2  The  stages  of  this  transformation  have  been  particularly  well  made  out  by  Mr.  Mar- 
shall, in  his  elaborate  Memoir  "  On  the  Development  of  the  Great  Anterior  Veins  in  Man 
and  Mammalia"  ("  Phil.  Trans*.,"  1850);  and  he  has  further  shown  that  some  vestiges  of 
the  original  arrangement  may  be  traced  even  in  the  normal  condition  of  the  venous  system 
in  the  adult. 


DEVELOPMENT   OF   THE   E-MBRYO. 


997 


rating  organs,  the  Placenta  and  the  foetal  Liver,  it  is  in  the  condition  of  arterial 
blood;  but,  being  mixed  in  the  vessels  with  that  which  has  been  returned  from 
the  trunk  and  lower  extremities,  it  loses  this  character  in  some  degree  by  the 
time  that  it  arrives  at  the  Heart.  In  the  right  auricle,  which  it  then  enters,  it 


The  Foetal  Circulation  :  1.  The  umbilical  cord  consisting  of  the  umbilical  vein  and  two  umbilical  arteries, 
proceeding  from  the  placenta  (2).  3.  The  umbilical  vein  dividing  into  three  branches ;  two  (4,  4)  to  be  dis- 
tributed to  the  liver;  and  one  (5),  the  ductus  venosus,  which  enters  the  inferior  vena  cava  (6).  7.  The  portal 
vein,  returning  the  blood  from  the  intestines,  and  uniting  with  the  right  hepatic  branch.  8.  The  right  auri- 
cle ;  the  course  of  the  blood  is  denoted  by  the  arrow  proceeding  from  8  to  9,  the  left  auricle.  10.  The  left 
ventricle;  the  blood  following  the  arrow  to  the  arch  of  the  aorta  (11),  to  be  distributed  through  the  branches 
given  off  by  the  arch  to  the  head  and  upper  extremities.  The  arrows  12  and  13  represent  the  return  of  the 
blood  from  the  head  and  upper  extremities  through  the  jugular  and  subclavian  veins,  to  the  superior  vena 
cava  (14),  to  the  right  auricle  (8),  and  in  the  course  of  the  arrow  through  the  right  ventricle  (15)  to  the  pul- 
monary artery  (16).  17.  The  ductus  arteriosus,  which  appears  to  be  a  proper  continuation  of  the  pulmonary 
artery;  the  offsets  at  each  side  are  the  right  and  left  pulmonary  artery  cut  off;  these  are  of  extremely  small 
size  as  compared  with  the  ductus  arteriosus.  The  ductus  arteriosus  joins  the  descending  aorta  (18, 18),  which 
divides  into  the  common  iliacs,  and  these  into  the  internal  iliacs,  which  become  the  umbilical  arteries  (19) 
and  return  the  blood  along  the  umbilical  cord  to  the  placenta  and  external  iliacs  (20),  which  are  continued 
into  the  lower  extremities.  The  arrows  at  the  termination  of  these  vessels  mark  the  return  of  the  venous 
blood  by  the  veins  to  the  inferior  cava. 

would  be  also  mixed  with  the  venous  blood  brought  thither  by  the  descending 
Cava,  were  it  not  that  a  very  curious  provision  t  exists,  to  prevent  (in  great  de- 
gree, if  not  entirely)  any  such  further  dilution.  The  Eustachian  valve  has 


'=998  OF   GENERATION. 

!^een  found,  by  the  experiments  of  Dr.  J.  Reid,1  to  serve  the  purpose  of  direct- 
jng  the  arterial  blood,  which  flows  upwards  from  the  ascending  Cava,  through 
the  foramen  ovale,  into  the  left  auricle,  whence  it  passes  into  the  left  ventricle ; 
whilst  it  also  directs  the  venous  blood,  that  has  been  returned  by  the  descending 
Cava,  into  the  right  ventricle.  When  the  ventricles  contract,  the  arterial  blood 
which  the  left  contains  is  propelled  into  the  ascending  Aorta,  and  supplies  the 
branches  that  proceed  to  the  head  and  upper  extremities,  before  it  undergoes 
any  admixture ;  whilst  the  venous  blood,  contained  in  the  right  ventricle,  is 
forced  through  the  Pulmonary  artery  and  Ductus  Arteriosus  into  the  descend- 
ing Aorta,  mingling  with  the  arterial  current  which  that  vessel  previously  con- 
veyed, and  passing  thus  to  the  trunk  and  lower  extremities.  Hence  the  head 
and  superior  extremities,  whose  development  is  required  to  be  in  advance  of 
that  of  the  lower,  are  supplied  with  blood  nearly  as  pure  as  that  which  returns 
from  the  placenta ;  whilst  the  rest  of  the  body  receives  a  mixture  of  this  with 
what  has  previously  circulated  through  the  system ;  and  of  this  mixture  a  por- 
tion is  transmitted  to  the  placenta,  to  be  renovated  by  coming  into  relation  with 
the  maternal  fluid.  At  birth,  the  course  of  the  current  is  entirely  changed  by 
its  diversion  into  the  Lungs,  which  takes  place  immediately  on  the  first  inspi- 
ration. The  Ductus  Venosus  and  Ductus  Arteriosus  soon  shrivel  into  liga- 
ments; the  Foramen  Ovale  becomes  closed  by  its  valve;  and  the  circulation, 

Fig.  269. 


An  embryo  Dog,  representing  the  junction  of  the  umbilical  vesicle  with  the  intestinal  canal :  a,  rudiment- 
ary nostrils;  b,  rudimentary  eyes;  c,  the  first  visceral  arch;  d,  the  second  visceral  arch  ;  e,  the  right,/,  the 
left  auricular  appendage ;  g,  the  right,  h,  the  left  ventricle  of  the  heart ;  i,  the  aorta ;  k,  the  liver,  between 
the  two  lobes  of  which  is  perceived  the  divided  orifice  of  the  omphalo-mesenteric  vein ;  I,  the  stomach ;  m,  the 
intestine,  communicating  with  the  umbilical  vesicle ;  n,  o,  the  Wolfiian  bodies ;  p,  the  allantois ;  q,  the  upper 
extremities ;  r,  the  lower  extremities.  After  Bischoff. 

»  "Edinb.  Med.  and  Surg.  Journal,"  vol.  xliii. ;  and  "  Anat.,  Physiol.,  and  Pathol.  Re- 
searches," Chap.  ix. 


DEVELOPMENT   OF  THE   EMBRYO.  999 

which  was  before  carried  on  upon  the  plan  of  that  of  the  higher  Reptiles,  now 
becomes  that  of  the  complete  Bird  or  Mammal.  It  is  by  no  means  unfrequent, 
however,  for  some  arrest  of  development  to  prevent  the  completion  of  these 
changes;  and  various  malformations,  involving  an  imperfect  discharge  of  the 
function,  may  hence  result. 

1005.  The  Alimentary  Canal  has  been  shown  (§  997)  to  have  its  origin  in 
the  blastodermic  vesicle ;  being  a  portion  pinched  off  (as  it  were)  from  that  part 
of  it  which  is  just  beneath  the  spinal  column  of  the  embryo,  whilst  the  remain- 
der, which  is  at  that  time  the  largest  part  of  it,  forms  the  vitelline  or  umbilical 
vesicle.  In  its  earliest  form  it  is  merely  a  long  narrow  tube  (Fig.  269,  m), 
nearly  straight,  and  communicating  with  the  umbilical  vesicle  (n,  n)  at  about 
the  middle  of  its  length;  thus  it  may  be  regarded  as  composed  of  the  union  of 
two  divisions,  an  upper  and  a  lower.  At  first,  neither  mouth  nor  anus  exists; 
but  these  are  formed  early  in  the  second  month,  if  not  before.  The  tube 
gradually  manifests  a  distinction  into  its  special  parts,  oesophagus,  stomach, 
small  intestine,  and  large  intestine ;  and  the  first  change  in  its  position  occurs 
in  the  stomach,  which,  from  being  disposed  in  the  line  of  the  body,  takes  an 
oblique  direction.  The  curves  of  the  large  and  small  intestines  present  them- 
selves at  a  later  period.  It  is  at  the  lower  part  of  the  small  intestine,  near  its 
termination  in  the  large,  that  the  entrance  of  the  vitelline  duct  exists ;  and  a 
remnant  of  this  canal  is  not  unfrequently  preserved  throughout  life,  in  the  form 
of  a  small  pouch  or  diverticulum  from  that  part  of  the  intestine. — In  immediate 
connection  with  the  intestinal  tube,  we  find  the  first  rudiment  of  the  Liver, 
which  is  formed  by  the  thickening  of  the  cells  in  the  wall  of  the  canal,  at  the 
spot  at  which  the  hepatic  duct  is  subsequently  to  discharge  itself.  This  thick- 
ening increases,  so  as  to  form  a  projection  upon  the  exterior  of  the  canal ;  and 
soon  afterwards  the  lining  membrane  of  the  intestine  dips  down  into  it,  so  that 
a  kind  of  caecum  is  formed,  surrounded  by  a  mass  of  cells,  as  shown  in  Fig. 
270.  The  increase  of  the  organ  seems  to  take  place  by  a  continual  new  bud- 
ding forth  of  cells  from  its  peripheral  portion;  and  a  considerable  mass  is  thus 
formed,  before  the  caecum  in  its  interior  undergoes  any  extension  by  ramifica- 
tions into  it.  Gradually,  however,  the  cells  of  the  exterior  become  metamor- 
phosed into  fibrous  tissue  for  the  investment  of  the  organ ;  those  of  the  interior 
break  down  into  ducts,  which  are  developed  in  continuity  with  the  caecum 
derived  from  the  intestine,  and  which  are  lined  by  muscular  and  fibrous  tissues 
developed  from  the  primitive  cellular  blastema;  whilst  those  which  occupy  the 
intervening  space,  and  which  form  the  bulk  of  the  gland,  give  origin  to  the 
proper  secreting  cells,  which  are  now  to  come  into  active  operation.  As  this 
is  going  on,  the  hepatic  mass  is  gradu- 
ally removed  to  a  distance  from  the  Fig.  270. 
wall  of  the  alimentary  canal ;  and  the 
caecum  is  narrowed  and  lengthened,  so 
as  to  become  a  mere  connecting  pedicle, 
forming,  in  fact,  the  main  trunk  of  the 
hepatic  duct.  In  the  Human  embryo, 
the  formation  of  the  liver  begins  at 
about  the  third  week  of  intra-uterine 
existence ;  the  organ  is  from  the  first  of 
very  large  size,  when  compared  with 
that  of  the  body  ;  and  between  the  third  Origin  of  the  Liver  from  the  intestinal  ^  in  ^ 

and  the  faith  weeks,  it  IS  One-half  _  the  embryo  of  the  Fowl,  on  the  fourth  day  of  incubation ; 
Weight  of  the  entire  embryo.  It  is  at  —a,  heart;  &,  intestine;  c,  everted  portion  giving 
that  period  divided  into  several  lobes,  origin  to  liver  ;d,  liver  ;e,  portion  of  vitelline  vesicle. 

By  the  third  lunar  month,  the  liver  ex- 
tends nearly  to  the  pelvis,  and  almost  fills  the  abdomen ;  the  right  side  now 


1000  OF   GENERATION. 

begins  to  gain  upon  the  left ;  the  gall-bladder  begins  to  appear  at  this  time. 
The  subsequent  changes  chiefly  consist  in  the  consolidation  of  the  viscus,  and 
the  diminution  of  its  proportional  size.  Up  to  the  period  of  birth,  however,  the 
bulk  of  the  liver,  relatively  to  that  of  the  entire  body,  is  much  greater  than  in 
the  adult ;  the  proportion  being  as  1  to  18  or  20  in  the  new-born  child,  whilst 
it  is  about  1  to  36  in  the  adult;  and  the  difference  between  the  right  and  left 
sides  is  still  inconsiderable.  During  the  first  year  of  extra-uterine  life,  how- 
ever, a  great  change  takes  place ;  the  right  lobe  increases  a  little  or  remains 
stationary,  whilst  the  left  lobe  undergoes  an  absolute  diminution,  being  reduced 
nearly  one-half;  and  as,  during  the  same  period,  the  bulk  of  the  rest  of  the 
body  has  been  rapidly  increasing,  the  proportion  is  much  more  reduced  during 
that  period  than  in  any  subsequent  one  of  the  same  length.  According  to 
Meckel,  the  liver  of  the  newly-born  infant  weighs  one-fourth  heavier  than  that 
of  a  child  of  eight  or  ten  months  old ;  and  as  the  weight  of  the  whole  body  is 
more  than  double  during  the  same  time,  it  is  obvious  that  the  change  in  the 
proportion  of  the  two  must  be  principally  effected  at  this  epoch.  The  liver 
seems  to  be  actively  engaged,  during  foetal  life,  in  the  depuration  of  the  blood 
(as  appears  from  the  accumulation  of  meconium,  which  is  chiefly  altered  bile, 
in  the  intestinal  canal  at  birth),  whilst  at  the  same  time  it  is  serving  as  a  blood- 
making  organ  (§  150,  note). — The  general  history  which  has  just  been  given  of 
the  development  of  the  Liver  seems  equally  applicable  to  the  other  glands  that 
are  evolved  from  the  parietes  of  the  Alimentary  canal,  such  as  the  Salivary 
glands  and  Pancreas  ;  since  they  all  seem  to  commence  in  little  masses  of  cells, 
formed  by  an  increased  development,  at  certain  spots,  of  the  layer  of  blastema 
which  originally  constitutes  its  wall ;  and  whilst  some  of  these  cells  give  origin 
to  the  proper  tissues  of  each  gland,  others  form  its  ducts  and  tubuli  by  their 
deliquescence. 

1006.  The  Lungs  also  are  developed  in  immediate  relation  with  the  upper 
part  of  the  Alimentary  canal,  their  first  rudiments  shooting  forth  as  a  pair  of 
budlike  processes  (Fig.  271,  a)  from  its  cesophageal  portion.  These  were 
originally  described  by  Von  Bar  as  hollow,  and  as  in  reality  diverticula  from 
the  tube  itself.  But  most  later  observers  agree  in  stating  that  the  budlike  pro- 
cesses are  not  at  first  hollow,  but  are  solid  aggregations  of  cells,  formed  by  a 
multiplication  of  the  cells  constituting  the  external  wall  of  the  alimentary  tube, 
into  which  its  internal  tunic  is  not  prolonged.  These  gradually  increase  in  size, 
extending  downwards  by  the  multiplication  of  their  component  cells  in  that  direc- 
tion :  and  cavities  are  formed  in  them  (probably,  as  in  the  preceding  instances, 
by  the  deliquescence  or  fusion  of  some  of  the  cells  of  their  interior),  which  at 
first  communicate  with  the  pharynx  by  separate  apertures ;  these,  however, 
coalescing  into  one,  as  the  channels  are  elongated  into  tubes,  and  the  pulmonary 
organs  are  removed  to  a  distance  from  their  point  of  exit.  This  process  com- 
mences, in  the  Chick,  about  the  4th  day 

Fig-  271.  of  incubation ;  and  on  the  5th  or  6th, 

the  lungs  are  completely  detached  from 
the  oesophagus,  and  each  has  its  own 
bronchial  tube  connecting  it  with  the 
trachea  common  to  both  (Fig.  271,  &). 
The  upper  portion  of  the  lung  has  much 
thicker  walls  than  the  lower ;  and  these 
appear  to  contain  a  large  quantity  of 
First  appearance  of  the  Lungs :  a,  in  a  Fowl  at  vesicular  parenchyma,  in  which  the  rami- 

f our  days ;  b,  in  a  Fowl  at  six  days;  c,  termination      fications   of  the    bronchial    tubes    subse- 

of  bronchus  in  a  very  young  Pig.  quently  extend  themselves.     About  the 

tenth    or   eleventh    day  of  incubation, 
these  ramifications  possess  nearly  their  permanent  character  and  situation.    The 


DEVELOPMENT   OF   THE   EMBRYO. 


1001 


first  trace  of  the  Glottis  appears  about  the  fifth  day ;  it  is  then  a  mere  slit  in 
the  walls  of  the  ossophagus,  resembling  that  by  which  the  ductus  pneumaticus 
of  some  Fishes  opens  into  the  alimentary  canal.  The  formation  of  the  cartila- 
ginous rings  of  the  trachea  does  not  commence  until  after  the  twelfth  day,  when 
they  first  appear  as  transverse  strise  on  the  median  line  of  the  front  only ;  they 
gradually  become  solid,  and  extend  themselves  on  either  side,  until  at  last  they 
nearly  meet  on  the  median  line,  on  the  back  or  vertebral  side  of  the  tube. — 
The  history  of  the  process,  in  the  Human  embryo,  appears  to  be  very  nearly 
the  same.  The  first  appearance  of  the  Lungs  takes  place  at  about  the  6th 
week,  at  which  time  they  are  simple  elevations  of  the  external  layer  of  the 
03sophageal  wall.  Their  surface,  however,  soon  becomes  studded  with  numerous 
little  wart-like  projections ;  and  these  are  caused  by  the  formation  of  correspond- 
ing enlargements  of  their  cavity.  These  enlargements  soon  become  prolonged, 
and  develop  corresponding  budlike  enlargements  from  their  sides;  and  in  this 
manner,  the  form  of  the  organs  is  gradually  changed,  a  progressive  increase  in 
their  bulk  taking  place  from  above  downwards,  in  consequence  of  the  extension 
of  the  bronchial  ramifications  from  the  single  tube  at  the  apex.  At  the  same 
time,  however,  a  corresponding  increase  in  the  amount  of  the  parenchymatous 
tissue  of  the  lung  is  taking  place ;  for  this  is  deposited  in  all  the  interstices 
between  the  bronchial  ramifications,  and  might  be  compared  with  the  soil  filling 
up  the  spaces  amongst  the  roots  of  a  tree.  It  is  in  this  parenchyma  that  the 
pulmonary  vessels  are  distributed ;  and  the  portion  of  it  whrch  extends  beyond 
the  terminations  of  the  bronchial  tubes  seems  to  act  as  the  nidus  for  their 
further  extension.  It  can  be  easily  shown  that,  up  to  a  late  period  of  the 
development  of  the  lungs,  the  dilated  terminations  of  the  bronchi  constitute  the 
only  air-cells  (Fig.  271,  c)  ;  but,  as  already  mentioned,  the  parenchyma  sub- 
sequently has  additional  cavities  formed  within  it. — It  is  a  fact  of  some  interest, 
as  an  example  of  the  tendency  of  certain  diseased  conditions  to  produce  a  return 
to  forms  which  are  natural  to  the  fostal  organism,  or  which  present  themselves 
in  other  animals,  that  up  to  a  late  period  in  the  development  of  the  Human 
embryo,  the  lungs  do  not  nearly  fill  the  cavity  of  the  chest,  and  the  pleura  of 
each  side  contains  a  good  deal  of  serous  fluid. 

1007.  The  embryological  development  of  the  Urinary  organs  in  Vertebrated 
animals  is  a  subject  of  peculiar  interest ;  owing  to  the  correspondence  which 
may  be  traced  between  the  transitory  forms  they  present  in  the  higher  classes, 
and  their  permanent  condition  in  the  lower.  In  this 
respect  there  is  an  evident  analogy  with  the  Respi- 
ratory system.  The  first  appearance  of  anything 
resembling  a  Urinary  apparatus  in  the  Chick,  is  seen 
on  the  second  half  of  the  third  day.  The  form  at 
that  time  presented  by  it,  is  that  of  a  long  canal, 
extending  on  each  side  of  the  spinal  column,  from 
the  region  of  the  heart,  towards  the  allantois  (Fig. 
269,  o,  o);  on  the  sides  of  this  are  a  series  of  ele- 
vations and  depressions,  indicative  of  the  incipient 
development  of  cseca.  On  the  fourth  day,  the  Cor- 
pora Wolffiana,  as  they  are  then  termed,  are  dis- 
tinctly recognized  as  composed  of  a  series  of  csecal 
appendages  which  are  attached  along  the  whole  course 
of  the  first-mentioned  canal,  opening  into  its  outer 
side  (Fig.  272,  1).  On  the  5th  day,  these  append- 
ages are  convoluted;  and  the  body  which  they  form  state  of  the  Urinary  and  Genital 
acquires  increased  breadth  and  thickness.  They  Apparatus  in  the  early  embryo  of 

,,         , .  ,    , ,  J      the    Bird :   1,   corpora  Wolffiana : 

evidently  then  possess  a  secreting  function,  and  the  2>  2>  their  excretory  ducts.  3j  kid. 
fluid  which  they  separate  is  .poured  by  their  long  neys;  4, ureter;  5,5, testis. 


1002  OF   GENERATION. 

straight  canals  (2,  2)  into  the  cloaca.  Between  their  component  shut  sacs, 
numbers  of  small  points  appear,  which  consist  of  little  clusters  of  convoluted 
vessels,  exactly  analogous  to  the  Corpora  Malpighiana  of  the  true  kidney.  These 
bodies  remain  as  the  permanent  urinary  organs  of  Fishes ;  but  in  the  higher 
Vertebrata  they  give  place  to  the  true  Kidneys,  the  development  of  which  com- 
mences in  the  Chick  about  the  5th  day.  These  are  seen  on  the  6th  day,  as 
lobulated  grayish  masses  (3),  which  seem  to  sprout  from  the  outer  edges  of  the 
Wolffian  bodies,  but  which  are  really  independent  formations  springing  from  a 
mass  of  blastema  behind  them ;  and  as  they  gradually  increase  in  size  and  advance 
in  development,  the  Wolffian  bodies  retrograde ;  so  that,  at  the  end  of  foatal  life,  the 
only  vestige  of  them  is  to  be  found  as  a  shrunk  rudiment,  situated  (in  the  male)  near 
the  testes. — The  history  of  the  development  of  the  Urinary  organs  in  the  Human 
embryo  seems  to  correspond  closely  with  the  foregoing.  The  Wolffian  bodies 
begin  to  appear  towards  the  end  of  the  first  month ;  and  it  is  in  the  course  of  the 
7th  week  that  the  true  Kidneys  first  present  themselves.  From  the  beginning  of 
the  3d  month,  the  diminution  in  the  size  of  the  Wolffian  bodies  goes  on  paripassu 
with  the  increase  of  the  Kidneys ;  and,  at  the  time  of  birth,  scarcely  any  traces 
of  the  former  can  be  found.  At  the  end  of  the  3d  month,  the  kidneys  consist 
of  seven  or  eight  lobes,  the  future  pyramids;  their  excretory  ducts  still  termi- 
nate in  the  same  canal,  which  receives  those  of  the  Wolffian  bodies,  and  of  the 
sexual  organs ;  and  this  opens,  with  the  rectum,  into  a  sort  of  cloaca,  or  sinus 
uro-genitalis,  analogous  to  that  which  is  permanent  in  the  oviparous  Vertebrata. 
The  Kidneys  are  at  this  time  covered  by  the  Suprarenal  capsules,  which 
equal  them  in  size ;  about  the  6th  month,  however,  these  have  decreased,  whilst 
the  kidneys  have  increased,  so  that  their  proportional  weight  is  as  1  to  2£.  At 
birth,  the  weight  of  the  Kidneys  is  about  three  times  that  of  the  Supra- Renal 
capsules,  and  they  bear  to  the  whole  body  the  proportion  of  1  to  80  ;  in  the 
adult,  however,  they  are  no  more  than  1  to  240.  The  Corpora  Wolffiana  are, 
when  at  their  greatest  development,  the  most  vascular  parts  of  the  body  next 
to  the  liver ;  four  or  five  branches  from  the  aorta  are  distributed  to  each,  and 
two  veins  are  returned  from  each  to  the  vena  cava.  The  upper  veins  and  their 
corresponding  arteries  are  converted  into  the  Renal  or  emulgent  vessels ;  and 
the  lower  into  Spermatic  vessels.  The  lobulated  appearance  of  the  kidney 
gradually  disappears ;  partly  in  consequence  of  the  condensation  of  the  areolar 
tissue  which  connects  the  different  parts,  and  partly  through  the  development  of 
additional  tubuli  in  the  interstices.  The  Urinary  Bladder  is  formed  quite  inde- 
pendently of  the  secreting  apparatus,  being  a  part  of  the  allantois,  which  itself 
serves  as  the  receptacle  for  the  urinary  secretion  formed  by  the  Corpora 
Wolffiana.  The  part  of  the  tube  below  this  forms  the  Cloaca,  or  common 
termination  of  the  intestinal  and  vesical  apparatus.  The  sides  of  this  cloaca, 
however,  gradually  approach  one  another,  so  as  to  form  a  transverse  partition, 
which  separates  the  Rectum  from  the  Genito-urinary  canal ;  and  the  urethra  of 
the  female  is  afterwards  separated  from  the  Vagina  by  a  similar  process. 

1008.  The  essential  parts  of  the  Generative  Apparatus,  namely,  the  Testes 
in  the  male,  and  the  Ovaria  in  the  female,  are  first  developed  in  immediate 
proximity  with  the  Corpora  Wolffiana  (Fig.  272,  5,  5),  and  have  been  supposed 
to  sprout  forth  from  them ;  this,  however,  is  not  really  the  case,  as  they  have 
an  independent  origin  in  a  mass  of  blastema  peculiar  to  themselves.  They  make 
their  first  appearance  in  the  Chick  about  the  fourth  day,  as  delicate  striae  on  the 
Wolffian  bodies ;  and  at  this  period  no  difference  can  be  detected  between  the 
Testes  and  the  Ovaria,  which  originate  in  precisely  the  same  manner.  Like 
the  kidneys,  the  germ-preparing  organs  increase  in  proportion  with  the  dimi- 
nution in  the  temporary  structures ;  at  first,  their  efferent  ducts  open  into  those 
of  the  Wolffian  bodies,  but  they  are  subsequently  separated  by  the  formation  of 
a  partition,  like  that  which  separates  the  rectum  from  the  cloaca.  In  the 


DEVELOPMENT   OP  THE   EMBRYO.  1003 

Human  embryo,  the  rudiments  of  the  sexual  organs — whether  testes  or  ovaria, 
— first  present  themselves  soon  after  the  kidneys  make  their  appearance,  that 
is,  towards  the  end  of  the  7th  week.  They  are  at  first  much  prolonged,  and 
seem  to  consist  of  a  kind  of  soft,  homogeneous  blastema,  in  which  the  structure 
characteristic  of  each  subsequently  develops  itself.  The  Testis  gradually  as- 
sumes its  permanent  form ;  the  epididymis  appears  in  the  tenth  week ;  and  the 
gubernaculum  (a  membranous  process  from  the  filamentous  tissue  of  the  scrotum, 
analogous  to  the  round  ligament  arising  from  the  labiuni  and  attached  to  the 
ovary  of  the  female),  which  is  originally  attached  to  the  vas  deferens,  gradually 
fixes  itself  to  the  lower  end  of  the  testis  or  epididymis.  The  Testes  begin  to 
descend  at  about  the  middle  period  of  pregnancy ;  at  the  seventh  month  they 
reach  the  inner  ring;  in  the  eighth  they  enter  the  passage  ;  and 'in  the  ninth 
they  usually  descend  into  the  scrotum.  The  cause  of  this  descent  is  not  very 
clear  :  it  can  scarcely  be  due  merely,  as  some  have  supposed,  to  the  contraction 
of  the  gubernaculum ;  since  that  does  not  contain  any  fibrous  structure,  until 
after  the  lowering  of  the  testes  has  commenced.  It  is  well  known  that  the  testes 
are  not  always  found  in  the  scrotum  at  the  time  of  birth,  even  at  the  full  period. 
Upon  an  examination  of  97  new-born  infants,  Wrisberg  found  both  testes  in 
the  scrotum  in  67,  one  or  both  in  the  canal  in  17,  in  8  one  testis  in  the  abdo- 
men, and  in  3  both  testes  within  the  cavity.  Sometimes  one  or  both  testes  re- 
main in  the  abdomen  during  the  whole  of  life ;  but  this  circumstance  does  not 
seem  to  impair  their  function.  This  condition  is  natural,  indeed,  in  the  ram. — 
The  Ovary  undergoes  much  less  alteration,  either  in  its  intimate  structure,  or 
in  its  position.  The  efferent  canal  of  the  genital  apparatus,  which  in  the  male 
forms  a  continuous  connection  with  the  tubular  structure  of  the  testes,  remains 
detached  from  the  ovary  in  the  female,  having  a  free  terminal  aperture,  and 
thus  constituting  the  Fallopian  tube.  These  tubes  are  at  first  distinct  on  the 
two  sides,  but  they  gradually  coalesce  higher  and  higher  up  ;*  and  it  is  by  an 
increased  development  of  this  coalesced  portion,  that  the  Uterus  is  formed,  the 
homologue  of  which  in  the  male  seems  to  be  the  (so  called)  Vesicula  prostatica, 
or  "sinus  pocularis,"  which  is  sometimes  developed  to  a  considerable  size,  and 
the  relation  of  which  to  the  orifices  of  the  vasa  deferentia  is  then  seen  to  be 
essentially  the  same  as  that  of  the  female  uterus  to  the  Fallopian  tubes.3 

1009.  The  history  of  the  development  of  the  External  Organs  of  Generation 
in  the  two  sexes  presents  matter  of  great  interest,  from  the  light  which  is 
thrown  by  a  knowledge  of  it  upon  the  malformations  of  these  organs,  which  are 
among  the  most  common  of  all  departures  from  the  normal  type  of  Human 
organization. — Not  only  is  the  distinction  of  sexes  altogether  wanting  at  first ; 
but  the  conformation  of  the  external  parts  of  the  apparatus  is  originally  the 
same  in  Man  and  the  higher  Mammalia,  as  it  permanently  is  in  the  Oviparous 
Vertebrata*  For,  about  the  5th  or  6th  week  of  embryonic  life,  the  opening  of 
a  cloaca  may  be  seen  externally,  which  receives  the  termination  of  the  intestinal 
canal,  the  ureters,  and  the  efferent  ducts  of  the  sexual  organs  j  but  at  the  10th 
or  llth  week,  the  anal  aperture  is  separated  from  that  of  the  genito-urinary 
canal  or  "uro-genital  sinus,"  by  the  development  of  a  transverse  band;  and  the 
uro-genital  sinus  itself  is  gradually  separated,  by  a  process  of  division  extending 
from  before  backwards  or  from  above  downwards,  into  a  "  pars  urinaria"  and  a 
"pars  genitalis,"  the  former  of  which,  extending  towards  the  urachus,  is  converted 
into  the  urinary  bladder.  A  partial  representation  of  this  phase  of  development 

1  For  a  sketch  of  those  different  conditions  presented  by  the  Uterus  in  the  several  orders 
of  the  Mammalian  class,  which  depend  upon  the  degree  of  this  coalescence,  see  the  Author's 
"Princ.  of  Phys.,  Gen.  and  Comp.,"  §  326,  aa,  Am.  Ed. 

2  See  Prof.  E.  Weber's  "Zusatze  zur  Lehre  vom  Baue  undden  Verrichtungen  der  Ge- 
schlechtsorgane,"  Leipzig,  1846. 


1004 


OP   GENERATION. 


is  found  in  the  permanent  condition  of  the  Struthious  Birds  and  of  the  Impla- 
eental  Mammalia.  The  external  opening  of  this  canal  is  soon  observed  to  be 
bounded  by  two  folds  of  skin,  the  rudiments  of  the  labia  majora  in  the  female, 
and  of  the  two  halves  of  the  scrotum  in  the  male ;  whilst  between  and  in  front 
of  these,  there  is  formed  a  penis-like  body,  surmounted  by  a  gland,  and  cleft  or 
furrowed  along  its  under  surface.  This  body  in  the  female  is  retracted  into  the 
genito-urinary  canal,  and  becomes  the  clitoris ;  whilst  the  margins  of  its  furrow 
are  converted  into  the  nymphae  or  labia  minora.  In  the  male,  on  the  other 
hand,  it  increases  in  prominence,  and  becomes  the  penis ;  and  the  margins  of 
the  furrow  at  its  under  surface  unite  (at  about  the  14th  week),  and  form  a  con- 
tinuation of  the  now  contracted  genito-urinary  canal — the  previous  orifice  of 
which  then  closes  up.  Now  in  a  large  proportion  of  cases  of  so-called  Herma- 

Fig.  273. 


Urinary  and  Generative  Organs  of  a  Human  Embryo  measuring  3%  inches  in  length.  A.  General  view  of 
these  parts:  1,  suprarenal  capsules;  2,  kidneys;  3,  ovary;  4,  Fallopian  tube;  5,  uterus;  6,  intestine;  7,  the 
bladder.  B.  Bladder  and  generative  organs  of  the  same  embryo  viewed  from  the  side  :  1,  the  urinary  bladder ; 
2,  urethra ;  3,  uterus  (with  two  cornua) ;  4,  vagina ;  5,  part  as  yet  common  to  the  vagina  and  urethra ;  6, 
common  orifice  of  the  urinary  and  generative  organs ;  7,  the  clitoris,  c.  Internal  generative  organs  of  the 
same  embryo :  1,  the  uterus ;  2,  the  round  ligaments ;  3,  the  Fallopian  tubes ;  4,  the  ovaries ;  5,  the  remains 
of  the  Wolffian  bodies.  D.  External  generative  organs  of  the  same  embryo :  1,  the  labia  majora ;  2,  the 
nymphje;  3,  the  clitoris.  After  Muller. 

phrodism,  there  has  been  either  a  want  of  completeness  in  the  development  of 
the  male  organs,  so  that  they  present  a  greater  or  less  degree  of  resemblance  to 
those  of  the  female ;  or  the  developmental  process  has  gone  on  to  an  abnormal 
extent  in  the  female  organs,  so  that  they  come  to  present  a  certain  degree  of 
resemblance  to  those  of  the  male.  One  of  the  most  common  malformations  of 
the  male  organs  is*  "  hypospadias,"  or  an  abnormal  opening  of  the  urethra  at  the 
base  of  the  penis ;  this  arises  from  incompleteness  in  the  closure  of  the  edges  of 
its  original  furrow.  But  when  the  developmental  process  has  been  checked  at 
an  earlier  period,  the  uro -genital  sinus  may  retain  more  nearly  its  original  cha- 
racter, and  may  have  a  wide  external  opening  beneath  the  root  of  the  penis,  so 


DEVELOPMENT  OF  THE  EMBRYO.  1005 

as  to  resemble  the  female  vagina,  whilst  the  penis  is  itself  destitute  of  any  trace 
of  the  urethral  canal;  in  some  of  these  cases,  again,  the  testes  have  not  descended 
into  the  scrotum ;  whilst  the  absence  of  beard,  the  shrillness  of  the  voice,  and 
the  fulness  of  the  mammae,  have  contributed  to  impart  a  feminine  character  to 
these  individuals,  their  male  attributes,  however,  being  determined  by  the  semi- 
niferous character  of  the  essential  organ,  the  testes.1  In  the  female  organs,  on 
the  other  hand,  a  greater  or  less  degree  of  resemblance  to  those  of  the  male  may 
be  produced  by  the  enlargement  of  the  clitoris,  by  its  furrowing  or  complete 
perforation  by  the  urethra,  by  the  closure  of  the  entrance  of  the  vagina  and  the 
cohesion  of  the  labia,  so  as  to  present  a  likeness  to  the  unfissured  perineum  and 
scrotum  of  the  male,  by  the  descent  of  the  ovaries  through  the  inguinal  ring 
into  the  position  of  the  male  testes,  by  the  imperfect  development  of  the  uterus 
and  mammae ;  and  with  these  are  usually  associated  roughness  of  the  voice  and 
growth  of  hair  on  the  chin,  and  a  psychical  character  more  or  less  virile.  True 
Hermaphrodism,  in  which  there  is  an  absolute  combination  of  the  essential  male 
and  female  organs  in  the  same  individual,  is  comparatively  rare.  It  may  occur 
under  the  forms  of  lateral  hermaphrodism,  in  which  there  is  a  genuine  ovary 
on  one  side  and  a  testis  on  the  other,  in  which  case  the  external  organs  are 
usually  those  of  a  hypospadic  male;  transverse  hermaphrodism,  in  which  the 
external  and  internal  organs  do  not  correspond,  the  former  being  male  and  the 
latter  female,  or  vice  versa; — and  double  or  vertical  hermaphrodism,  in  which 
the  proper  organs  characteristic  of  one  sex  have  existed,  with  the  addition  of 
some  of  those  of  the  other ;  this  is  the  rarest  of  all,  and  it  is  not  certain  that 
the  coexistence  of  testes  and  ovaria  on  the  same  side  has  ever  been  observed  in 
the  Human  species.3 

1010.  We  have  now  to  follow  the  course  of  the  development  of  the  principal 
organs  of  Animal  life ;  and  shall  first  notice  that  of  the  Skeleton. — We  have 
seen  that,  in  the  embryo  of  the  Vertebrated  animal,  the  future  vertebral  column 
is  marked  out  at  an  earlier  period  than  any  other  permanent  organ  (§  997) ; 
and  that  indications  of  a  division  into  vertebrae  are  very  speedily  presented  in 
the  embryo  of  the  higher  classes.  The  earliest  formation,  however,  is  one  of 
which  we  recognize  no  traces  in  the  adult  condition  of  Man ;  namely,  a  longitu- 
dinal column,  tapering  off  to  a  point  at  the  cranial  and  caudal  extremities  of  the 
embryo,  and  occupying  the  place  of  the  future  bodies  of  the  vertebrae.  This,  which 
is  termed  the  "  chorda  dorsalis,"  is  of  gelatinous  consistence,  and  is  composed 
entirely  of  cells ;  it  is  inclosed  in  a  sheath,  which  gradually  acquires  the  struc- 
ture of  a  fibrous  membrane,  and  which  also  invests  the  neural  axis  itself ;  and 
this  condition  is  persistent  in  the  Amphioxus  and  the  Myxinoid  Fishes,3  which 
have  never  any  other  spinal  column  than  the  chorda  dorsalis.  The  vertebrae 
seem  to  be  developed,  in  the  inferior  Vertebrata,  in  the  fibrous  sheath  of  the 
chorda  dorsalis;  but  in  Birds  and  Mammals,  the  quadrangular  plates  which 
show  themselves  at  a  very  early  period  (Plate  II.  Fig.  12)  appear  to  have  an 
independent  origin.  These  gradually  increase  in  number  and  size,  so  as  to  sur- 
round the  chorda  both  above  and  below;  sending  out,  at  the  same  time,  pro- 
longations from  the  inferior  surface,  to  form  the  arches  destined  to  inclose  the 
Spinal  Cord  or  neural  axis,  which  are  hence  termed  by  Prof.  Owen  the  neural 
arches.  In  this  primitive  condition,  the  body  and  arches  of  each  vertebra  are 
formed  by  one  piece  on  each  side  ;  and  these,  becoming  cartilaginous,  are  united 
inferiorly  by  a  suture,  so  as  to  inclose  the  chorda  in  a  sort  of  case  formed  by 

1  The  vesicula  prostatica,  or  "  uterus  masculinus,"  has  presented  an  unusual  development 
in  some  of  these  cases;  see  Prof.  Weber  (loc.  cit.),  and  Prof.  Theile's  "Account  of  a  Case 
of  Hypospadias,"  in  "Muller's  Archiv.,"  1847. 

2  On  the  subject  of  Hermaphrodism,  see  Prof.  Simpson's  Article  in  the   "  Cyclop,  of 
Anat.  and  Phys.,"  vol.  ii. 

3  "Princ.  of  Phys.,  Gen.  and  Comp.,"  \\  321  a,  322,  and  322  a,  Am,  Ed. 


1006 


OF   GENERATION. 


the  bodies  of  the  vertebras,  which  are  still  hollow,  so  as  to  allow  the  segments 
of  the  chorda,  partially  separated  from  each  other,  to  communicate  together. 
This  condition  also  remains  persistent  in  certain  of  the  Cartilaginous  Fishes. 
With  the  concentric  growth  of  the  bodies  of  the  vertebrae,  however,  the  chorda 
dorsalis  gradually  wastes,  and  at  last  disappears;  but  previously  to  its  disap- 
pearance, the  ossification  of  the  bodies  and  neural  arches  of  the  vertebrae 
begins,  the  former  from  a  single  point  on  the  median  line,  the  latter  by  separate 
points  on  the  two  sides. — The  complete  typical  vertebra  (Fig.  274,  A)  essentially 
consists,  according  to  Prof.  Owen,1  of  the  centrum,  around  which  are  arranged 
four  arches  inclosed  by  processes  in  connection  with  it :  viz.,  superiorly,  the 
neural  arch,  which  incloses  the  neural  axis,  and  is  formed  by  a  pair  of  "neura- 
pophyses" (fc,  n)  and  a  "neural  spine"  (n,  s) ;  inferiorly,  the  hgemal  arch,  which 
is  in  like  special  relation  with  the  centres  of  the  circulation,  but  may  be  ex- 
panded around  the  visceral  cavity  generally,  and  which  is  formed  of  a  pair  of 
"  hsemapophyses"  (h,  h),  and  the  "  hsemal  spine"  (h,  s) ;  and  two  lateral  arches, 
inclosing  vascular  canals,  which  are  bounded  by  the  "  diapophyses"  (d,  d) 
and  the  "  parapophyses"  (p,  p),  and  are  completed  by  the  "  pleurapophyses" 
(pi,  pi).  Of  these  elements,  the  centrum  is  the  most  constant ;  and  next^to 
these  are  the  neural  arches,  which  we  find  in  every  part  of  the  vertebral 
column  through  which  the  neural  axis  passes,  and  which  are  enormously  de- 
veloped in  the  cranial  segments,  in  accordance  with  the  high  development  of  the 
nervous  mass.  The  haemal  arches  are  often  almost  entirely  deficient,  as  in  the 


Fig.  274. 


IB     ns 


Elements  of  a  Vertebra,  according  to  Prof.  Owen :  A,  ideal  typical  vertebra  ;  B,  actual  thoracic  vertebra  of  a 
Bird ;  c,  centrum,  giving  off  d,  d,  the  diapophyses,  and  p,  p,  the  parapophyses ;  the  neural  arch,  inclosing 
the  spinal  cord  *,  is  formed  by  n,  n,  the  neurapophyses  and  n,  s,  the  neural  spine;  the  haemal  arch,  inclosing 
the  great  centres  of  the  circulation,  is  formed  by  h,  h,  the  haemapophyses,  and  h,  s,  the  haemal  spine.  From 
both  the  neurapophyses  and  hasmapophyses  may  be  given  off  the  zygapophyses,  z,  z.  The  lateral  arches, 
which  may  inclose  the  vertebral  arteries  0  o,  are  completed  by  the  pleurapophyses,  p,  1;  these  in  B  are  bent 
downwards,  so  as  to  form  part  of  the  haemal  arch,  and  give  off  the  diverging  appendages  a,  a. 

cervical  and  lumbar  vertebras  of  Man  and  the  Mammalia :  but  in  the  dorsal  verte- 
brae they  are  very  largely  developed,  and  the  elements  of  the  lateral  arches  are 
brought  into  connection  with  them,  so  as  to  form  the  inclosure  of  the  visceral 
cavity  (Fig.  274,  B).  From  the  pleurapophyses  are  occasionally  developed  a  pair 


1  See  his  "Archetype  Skeleton," his  "Lectures  on  Comparative  Anatomy,"  TO!,  ii.,  and 
his  "Discourse  on  the  Nature  of  Limbs." 


DEVELOPMENT   OF   THE    EMBRYO.  1007 

of  "diverging  appendages"  (a,  a),  which  are  well  seen  in  the  ribs  of  Birds; 
and  these  are  considered  by  Prof.  Owen  to  be  the  fundamental  elements  of  the 
bones  of  the  "  extremities"  or  "  limbs,"  those  of  the  anterior  extremity  being 
the  diverging  appendages  of  the  occipital  vertebra  (§  1011),  and  those  of  the 
posterior  extremity  standing  in  the  same  relation  to  one  of  the  sacral  vertebrse.1 
—  The  extremities  themselves  are  developed,  in  all  Vertebrata,  as  leaf  like  ele- 
vations from  the  parietes  of  the  trunk  (Fig.  269,  <?,  q,  r,  r)  ;  those  peculiarities 
.of  form  by  which  they  are  adapted  to  specialities  of  function  being  determined 
by  subsequent  processes  of  development.  Thus  in  the  Human  foatus,  the  fingers 
are  at  first  united  by  the  primitive  blastema,  as  if  webbed  for  swimming  ;  but 
this,  as  Prof.  Miiller  justly  remarks,  is  less  to  be  regarded  as  an  approximation 
to  the  form  of  the  extremity  characteristic  of  aquatic  animals,  than  as  the  primi- 
tive and  most  general  form  of  the  hand,  the  individual  parts  of  which  subse- 
quently become  more  completely  isolated  in  such  animals  as  require  to  use  them 
separately. 

1011.  It  is  in  the  cranial  segments  that  the  vertebral  elements  undergo 
their  most  remarkable  transformations,  the  departure  from  the  "  archetype" 
being  more  complete  in  Man  than  in  any  other  animal  ;  so  that  it  is  only  by 
tracing  them  through  their  simplest  to  their  most  complicated  forms  and  ar- 
rangements, that  the  true  nature  of  the  latter  can  be  elucidated.3  —  The  number 
of  the  segments  entering  into  the  skull  has  been  a  subject  of  much  discussion 
among  those  who  adopt  the  "  vertebral  theory"  of  its  composition  ;  but  Prof. 
Owen  agrees  with  Oken  (the  original  propounder  of  the  theory)  in  fixing  the 
number  at  four,  which  corresponds  with  that  of  the  primary  divisions  succeeding 
each  other  in  a  linear  series,  that  are  distinctly  marked  in  the  early  development 
of  the  Encephalon,  namely  (proceeding  from  behind  forwards),  the  Epencephalon, 
the  Mesencephalon,  the  Prosencephalon,  and  the  Rhinencephalon  ;3  and  also 
corresponding  with  the  number  of  the  nerves  of  special  sense,  the  Auditory, 
Gustative,  Optic,  and  Olfactory,  which  issue  from  this  part  of  the  neural  axis 
with  the  same  segmental  regularity  that  the  ordinary  sensori-motor  nerves  do 
elsewhere.4 

1  The  beautiful  chain  of  reasoning  by  which  this  position  is,  in  the  Author's  opinion, 
irrefutably  established,  is  contained  in  the  works  of  Prof.  Owen  already  referred  to  ;  a 
sketch  of  it,  and  of  the  whole  "  Vertebral  Theory,"  will  be  found  in  the  Author's  "  Princ. 
of  Phys.,  Gen.  and  Comp.,"  |  320  et  seq.,  Am.  Ed. 

2  See  especially  Prof.  Owen's  "Archetype  Skeleton,"  and  the  sketch  contained  in  the 
Author's  "Princ.  of  Phys.,  Gen.  and  Comp.,"  %%  320  *,  320  <  I,  Am.  Ed. 

3  The  Rhinencephalon  (consisting  of  the  Olfactive  ganglia)  is  seldom  distinctly  marked 
out  in  the  early  stage  of  development  of  the  higher  Vertebrata,  but  is  obvious  enough  in 
Fishes  (Fig.  171,  A). 

4  Under  the  guidance  of  the  unerring  light  of  Comparative  Anatomy  and  Development, 
the  composition  of  the  Cranial  portion  of  the  skull  —  consisting  of  the  bodies  and  neural  arches 
of  the  four  cranial  vertebrae  —  has  been  determined  by  Prof.  Owen  as  follows,  each  of  the 
"  elements"  enumerated  being  marked  as  distinct,  by  the  separateness  of  its  centre  of  ossi- 
fication. 

TABLE  I. 

Composition  of  the  Neural  Arches  of  the  Cranial  Vertebrae,  in  Man. 
I.  EPENCEPHALIC  OR  OCCIPITAL  VERTEBRA. 

Centrum  ;  Basi-occipital  portion  of  the  Occipital  bone. 

p  T  )  Coalesced  into  the  lateral  or  condyloid  portions  of  the  Occipital 

rarapopnyse&        (      bone>  the  parapopliyses  being  marked  by  the  scabrous  ridge 


> 

;   J      giving  attachment  to  the  rectus  lateralis  muscle. 
Neural  Spine;  Proper  Occipital  bone. 

II.  MESENCEPHALIC  OR  PARIETAL  VERTEBRA. 

Centrum  ;  Basi-sphenoid,  or  body  of  the  posteiior  or  spheno-temporal  part  of  the 
Sphenoid  bone. 


1008  OF   GENERATION. 

1012.  Within  the  Cranio-spinal  canal  thus  formed,  the  rudiment  of  the  Cere- 
bro-spinal  axis  is  found,  at  first  under  a  very  different  aspect  from  that  which 

Parapophyses  ;  Mastoid  portion  of  the  Temporal  bones. 
Neurapophyses  ;  Great  wings  of  Sphenoid  bone,  or  Ali-sphenoids. 
Neural  Spine;  Parietal  bone.s. 

III.  PROSENCEPHALIC  OB  FRONTAL  VERTEBRA. 

Centrum  ;  Pre-sphenoid,  or  body  of  the  anterior  or  spheno-orbital  part  of  the  Sphe- 
noid bone. 
Parapophyses ;  External  angular  processes  of  Frontal  bone  (the  post-frontals  of 

Fishes). 

Neurapophyses  ;  Small  wings  of  Sphenoid  bone,  or  Orbito-sphenoids. 
Neural  Spine;  Frontal  bone. 

IV.  RHINENCEPHALIC  OR  NASAL  VERTEBRA.  . 

Centrum;  Vomer. 

Neurapophyses;  Ossa  plana  of  Ethmoid  bone. 
Neural  Spine  ;  Nasal  bones. 

In  connection  with  the  foregoing,  we  have  two  ossified  "  sense-capsules ;"  the  Auditory 
formed  by  the  petrosal  portion  of  the  Temporal  bone;  and  the  Nasal  formed  by  the  prin- 
cipal part  of  the  Ethmoid  bone,  with  the  turbinate  bones. 

The  hcemal  arches  of  the  cranial  vertebrae  form  the  bones  of  the  Face  and  of  some  other 
parts,  as  will  be  seen  from  the  following  table : — 

TABLE  II. 

Composition  of  the  Hcemal  Arches  of  the  Cranial  Vertebrce,  in  Man. 
I.  EPENCEPHALIC  OR  OCCIPITAL  VERTEBRA. 
Pleurapophyses  ;  Scapulae. 

Diverging  Appendages  ;  Bones  of  Arm,  Forearm,  and  Hand. 
Hcemapophyses ;  Coracoid  processes  of  Scapulae    (Coracoid  bones  of  Oviparous 

Vertebra  ta). 
Hcemal  Spine  ;  Deficient. 

[The  Clavicles  and  first  segment  of  the  Sternum,  which  complete  the  Scapular  arch 
in  the  Mammalia,  are  regarded  by  Prof.  Owen  as  the  haemapophyses  and  haemal 
spine  of  the  atlas,  or  highest  vertebra  of  the  trunk.] 

II.  MESENCEPHALIC  OR  PARIETAL  VERTEBRA. 

Pleurapophyses  ;  Styloid  processes  of  Temporal  bone. 
Diverging  Appendages  ;  Greater  cornua  of  Hyoid  bone,  or  Thyro-hyals. 
Hcemapophyses  ;  Lesser  cornua  of  Hyoid  bone,  or  Cerato-hyals. 
Hcemal  Spine  ;  Body  of  Hyoid  bone. 

III.  PROSENCEPHALIC  OR  FRONTAL  VERTEBRA. 

Pleurapophyses  ;  Tympanic  portion  of  Temporal  bone. 
Diverging  Appendages  ;  Deficient. 
Hcemapophyses  ;  Articular  portion  of  Inferior  Maxilla. 
Hcemal  Spine  ;  Dental  portion  of  Inferior  Maxilla. 

IV.  RHINENCEPHALIC  OR  NASAL  VERTEBRA. 

Pleurapophyses  ;  Palatine  bones.  . 

Diverging  Appendages  ;  Pterygoid  and  Malar  bones,  with  squamosal  and  zygomatic 

portions  of  Temporal  bones. 
Hcemapophyses  ;  Superior  Maxillary  bones. 
Hcemal  Spine  ;  Intermaxillary  bones. 

Thus  we  see  that,  in  the  anterior  segment,  we  have  the  highest  development  of  the  visceral 
portion,  coexisting  with  the  lowest  development  of  the  neural ;  this  last  being  obviously 
related  to  the  comparatively  low  development  of  the  ganglionic  mass  which  it  is  destined  to 
protect. — The  development  of  the  soft  parts  of  the  face  takes  place  in  conformity  with  that 
of  the  vertebral  segments;  these  being  formed  by  "visceral  arches"  which  meet  on  the 
median  line  (Fig.  270,  c,  d  d} ;  and  the  knowledge  of  this  fact  enables  us  to  explain  those 
congenital  malformations  which  result  from  want  of  union  of  the  two  halves  on  the  median 
plane,  such  as  cleft  palate  and  harelip. 


DEVELOPMENT   OF   THE   EMBRYO.  1009 

it  subsequently  presents,  especially  as  regards  the  relative  proportions  of  its 
different  segments.  The  encephalon,  at  about  the  sixth  week,  is  seen  as  a 
series  of  vesicles  arranged  in  a  line  with  each  other  (Fig.  275);  of  which  those 
that  represent  the  Cerebrum  (6)  are  the  smallest,  whilst  that  which  represents 
the  Cerebellum  (d)  is  the  largest.  The  latter  (or  Epencephalon),  as  in  Fishes, 
is  single,  covering  the  fourth  ventricle  on  the  dorsal  surface  of  the  Medulla 
Oblongata.  Anterior  to  this  is  the  single  vesicle  (a)  of  the  Corpora  Quadrige- 
mina  (or  Mesencephalon),  from  which  the  optic  nerve  chiefly  arises ;  this  has  in 
its  interior  a  cavity,  the  ventricle  of  Sylvius,  which  is  persistent  in  the  adult 
Bird,  though  obliterated  in  the  adult  Mammal.  In  front  of  this  is  the  vesicle 
(c)  of  the  Third  Ventricle  (or  Deutencephalon),  which  contains  also  the  Tha- 
lami  Optici ;  as  development  proceeds,  this,  like  the  preceding,  is  covered  by 
the  enlarged  hemispheres  ;  whilst  its  roof  becomes  cleft  anteriorly  on  the 
median  line,  so  as  to  communicate  with  the  cavities  which  they  include.  Still 
more  anteriorly  (6)  is  the  double  vesicle  (or  Prosencephalon)  which  represents 
the  hemispheres  of  the  Cerebrum ;  this  has  a  cavity  on  either  side,  the  floor 
of  which  is  formed  by  the  Corpora  Striata,  and  which  has  at  first  no  opening 
except  into  the  third  ventricle ;  the  "fissure  of  Sylvius"  (which  enables  the 
membranes  of  the  brain  to  be  reflected  into  the  lateral  ventricles)  being  formed 
at  a  later  period.  In  the  small  proportion  which  the  Cerebral  Hemispheres 
bear  to  the  other  parts,  the  absence  of  convolutions,  the  deficiency  of  commis- 
sures, and  the  general  simplicity  of  structure  of  the  whole,  there  is  a  certain 
correspondence  between  the  brain  of  the 
Human  embryo  at  this  period,  and  that  of 
a  Fish ;  but  the  resemblance  is  much 
stronger  between  the  foetal  brain  of  the 
Fish  and  that  of  the  Mammal ;  indeed,  at 
this  early  period  of  their  formation,  the 
two  could  scarcely  be  distinguished;  and  it 
is  the  large  amount  of  change  which  the 
latter  undergoes,  as  compared  with  the 
former,  that  causes  the  wide  dissimilarity 
of  their  adult  forms. — At  about  the  12th  & 
week  we  find  the  Cerebral  Hemispheres 
much  increased  in  size,  and  arching  back 
over  the  Thalami  and  Corpora  Quadrigemina 
(Fig.  276):  still,  however,  they  are  desti-  ** 

>    ,&     ,»  •  i  '  i«  3    •  c     j.i  Human  Embryo  of  sixth  week,  enlarged 

tute  of  convolutions,  and  imperfectly  con-     about  three  times .  fl}  vegicle  of  corpora  quad. 

nected  by  Commissures;  and  there  is  a  large  rigemina;  &,  vesicle  of  cerebral  hemispheres; 
Cavity  Still  existing  in  the  Corpora  Quad-  c,  vesicle  of  third  ventricle ;  d,  vesicle  for  cere- 
rigemina,  which  freely  Communicates  with  bellum  and  medulla  oblongata;  e,  auditory 

the  Third  Ventricle.  In  all  these  particu-  vesicle;.  f>  olfactory  fossa ;  h> liver ;  *  *  c™<*ai 
lars  there  is  a  strong  analogy  between  the 

condition  of  the  brain  of  the  Human  embryo  at  this  period,  and  that  of  the 
Bird. — Up  to  the  end  of  the  3d  month,  the  Cerebral  Hemispheres  present 
only  the  rudiments  of  anterior  lobes,  and  do  not  pass  beyond  that  grade  of 
development  which  is  permanently  characteristic  of  the  Marsupial  Mammalia, 
the  Thalami  being  still  but  incompletely  covered  in  by  them.  During  the 
4th  and  part  of  the  5th  months,  however,  the  middle  lobes  are  developed  from 
their  posterior  aspect,  and  cover  the  Corpora  Quadrigemina ;  and  the  posterior 
lobes,  of  which  there  was  no  previous  rudiment,  subsequently  begin  to  sprout 
from  the  back  of  the  middle  lobes,  remaining  separated  from  them,  however,  by 
a  distinct  furrow,  even  in  the  brain  of  the  mature  foetus,  and  sometimes  in  that 
of  older  persons.  In  these  and  other  particulars,  there  is  a  very  close  corre- 
64 


1010  OP   GENERATION. 

spondence  between  the  progressive  stages  of  development  of  the  Human  Cere- 
brum, and  those  which  we  encounter  in  the  ascending  scale  of  Mammalia.1 


Brain  of  Human  Embryo  at  twelfth  week:  A,  seen  from  behind;  B,  side  view;  c,  sectional  view;  a,  corpora 
quadrigemina ;  Z>,  b,  hemispheres ;  d,  cerebellum ;  e,  medulla  oblongata ;  /,  optic  thalamus :  g,  floor  of  third 
ventricle ;  i,  olfactory  nerve. 

1013.  The  development  of  the  two  principal  Organs  of  Sense,  the  Eye  and 
the  Ear,  has  been  made  the  subject  of  careful  study  (in  the  Chick)  by  Mr.  H. 
Gray.3 — f  he  development  of  the  Eye  commences  by  a  protrusion  from  the 
posterior  part  of  the  anterior  cerebral  vesicle,  representing  the  "  vesicle  of  the 
thalami  optici,"  which  is  at  that  time  hollow ;  and  the  cavity  of  the  protrusion 
is  continuous  with  that  of  the  vesicle  itself,  which  remains  as  the  "  third 
ventricle/'  This  protrusion  is  lined,  like  the  cerebral  vesicle,  with  granular 
matter,  which  gradually  becomes  distinctly  cellular,  forming  a  layer  of  a  truly 
ganglionic  character;  and  whilst  this  change  is  taking  place,  the  protrusion 
increases,  becomes  pear-shaped,  and  is  at  last  connected  only  by  a  narrow  pedicle 
with  the  vesicle  from  which  it  sprang.  This  pedicle  closes  up,  so  as  completely 
to  separate  the  two  cavities;  and  the  one  which  has  been  thus  budded  forth 
constitutes  the  rudiment  of  the  eye,  whilst  the  other  goes  on  to  form  the  gan- 
glionic bodies  at  the  base  of  the  cerebrum,  the  connecting  pedicle  becoming  the 
optic  nerve,  which  connects  the  retina  with  its  ganglionic  centre.  The  spherical 
extremity  of  the  protrusion  is  absorbed,  and  the  retina,  or  vesicular  lining, 
becomes  attached  to  the  margin  of  the  lens,  which  is  in  the  mean  time  developed 
in  the  interior  of  the  cavity,  and  is  at  first  completely  surrounded  by  the  retina. 
The  formation  of  the  coats  of  the  Eye  takes  place  subsequently;  the  development 
even  of  the  "  fibrous  lamina"  and  of  the  "  membrana  Jacobi"  of  the  retina  itself, 
not  taking  place  until  after  its  cellular  layer  has  been  very  distinctly  formed. 
It  is  a  curious  circumstance,  and  one  not  very  easy  to  account  for,  that  the  de- 
velopment of  the  Eye  should  take  place  from  the  Deutencephalic  and  not  from 
the  Mesencephalic  vesicle ;  as  it  is  in  the  latter  that  the  proper  "  optic  ganglia" 
originate,  with  which  the  optic  nerves  come  at  last  to  have  their  principal  con- 
nection, their  connection  with  the  "  thalami  optici"  being  much  less  close. — 
The  Auditory  apparatus  takes  its  origin  in  a  portion  of  the  Epencephalic  vesicle, 
which  protrudes  on  either  side,  its  cavity  at  first  communicating  with  that  of 
the  vesicle,  which  remains  permanent  as  the  "  fourth  ventricle."  As  its  pro- 
trusion increases,  it  becomes  elongated  and  pear-shaped,  and  is  only  connected 
with  the  central  mass  by  a  pedicle  whose  canal  gradually  closes  up ;  the  sac  thus 
cut  oft7  becomes  the  vestibular  cavity,  and  the  pedicle  the  auditory  nerve.  At 
first  there  is  no  vestige  either  of  cochlea,  semicircular  canals,  or  tympanic  appa- 
ratus ;  but  the  sac  presents  the  simple  character  which  it  permanently  retains 
in  the  Cephalopoda  and  the  lower  Fishes.  Gradually,  however,  the  semicircular 

1  See  an  account  of  the  observations  of  Prof.  Retzius  on  the  Development  of  the  Cere- 
brum, in  the  "  Archives  d'Anatomie  Generale  et  de  Physiologic,"  1846. 
a  "  Philosophical  Transactions,"  1850. 


DEVELOPMENT   OF    THE   EMBRYO.  1011 

canals  are  developed,  by  a  contraction  and  folding  in  of  tlie  walls  of  the  vesti- 
bular  sac ;  and  the  cochlea  is  probably  formed  as  an  offset  from  it.  At  the 
same  time,  the  formation  of  cartilage,  and  subsequently  of  bone,  takes  place 
around  the  auditory  sac  and  its  prolongations,  forming  the  "  sense-capsule," 
which,  in  the  higher  Yertebrata,  coalesces  with  the  vertebral  elements  to  form 
the  temporal  bone. — It  is  very  interesting  to  remark,  that  the  membranous 
labyrinth,  between  the  eighth  and  thirteenth  days  in  the  Chick,  has  a  structure 
almost  precisely  similar  to  that  of  the  retinal  expansion  of  the  same  period ; 
consisting,  like  it,  of  a  distinct  but  very  delicate  fibrous  mesh,  in  the  spaces 
between  which  are  deposited  a  quantity  of  granular  matter  and  numerous 
nucleated  cells,  whilst  its  exterior  is  composed  of  a  dense  mass  of  nuclei,  almost 
precisely  analogous  to  the  granular  particles  which  form  a  large  part  of  the 
entire  substance  of  the  retina. 

1014.  There  can  be  no  reasonable  doubt,  that  the  developmental  process 
must  be  greatly  influenced  by  the  quality  of  the  nutriment  supplied  by  the 
maternal  blood.  "  We  have  demonstrative  evidence,"  says  Dr.  A.  Combe,1 
"  that  a  fit  of  passion  in  a  nurse  vitiates  the  quality  of  the  milk  to  such  a 
degree  as  to  cause  colic  and  indigestion  (or  even  death)  in  the  suckling  infant. 
If,  in  the  child  already  born,  and  in  so  far  independent  of  its  parent,  the  relation 
between  the  two  is  thus  strong,  is  it  unreasonable  to  suppose  that  it  should  be 
yet  stronger,  when  the  infant  lies  in  its  mother's  womb,  is  nourished  indirectly 
by  its  mother's  blood,  and  is,  to  all  intents  and  purposes,  a  part  of  her  own 
body  ?  If  a  sudden  and  powerful  emotion  of  her  own  mind  exerts  such  an 
influence  upon  her  stomach  as  to  excite  immediate  vomiting,  and  upon  her  heart 
as  almost  to  arrest  its  motion  and  induce  fainting,  can  we  believe  that  it  will 
have  no  effect  on  her  womb  and  the  fragile  being  contained  within  it  ?  Facts 
and  reason,  then,  alike  demonstrate  the  reality  of  the  influence  :  and  much 
practical  advantage  would  result  to  both  parent  and  child,  were  the  conditions 
and  extent  of  its  operations  better  understood."  Among  facts  of  this  class, 
there  is,  perhaps,  none  more  striking  than  that  quoted  by  the  same  author  from 
Baron  Percy,  as  having  occurred  after  the  siege  of  Landau  in  1793.  In  addition 
to  a  violent  cannonading,  which  kept  the  women  for  some  time  in  a  constant 
state  of  alarm,  the  arsenal  blew  up  with  a  terrific  explosion,  which  few  could 
hear  with  unshaken  nerves.  Out  of  92  children  born  in  that  district  within  a 
few  months  afterwards,  Baron  Percy  states  that  16  died  at  the  instant  of  birth; 
33  languished  for  from  8  to  10  months,  and  then  died ;  8  became  idiotic,  and 
died  before  the  age  of  5  years ;  and  2  came  into  the  world  with  numerous  frac- 
tures of  the  bones  of  the  limbs,  caused  by  the  cannonading  and  explosion. 
Here,  then,  is  a  total  of  59  children  out  of  92,  or  within  a  trifle  of  2  out  of 
every  3,  actually  killed  through  the  medium  of  the  Mother's  alarm  and  the 
natural  consequences  upon  her  own  organization ;  an  experiment  (for  such  it  is 
to  the  Physiologist)  upon  too  large  a  scale  for  its  results  to  be  set  down  as  mere 
"  coincidences." — No  soundly  judging  Physiologist  of  the  present  day  is  likely 
to  fall  into  the  popular  error  of  supposing  that  "  marks"  upon  the  Infant  are 
to  be  referred  to  some  transient  though  strong  impression  upon  the  imagination 
of  the  Mother;  but  there  appear  to  be  a  sufficient  number  of  facts  on  record,  to 
prove  that  habitual  mental  conditions  on  the  part  of  the  Mother  may  have  in- 
fluence enough,  at  an  early  period  of  gestation,  to  produce  evident  bodily 
deformity,  or  peculiar  tendencies  of  the  mind.  That  the  mental  state  of  the 
Mother  can  produce  important  alterations  in  her  own  blood,  seems  demonstrated 
by  the  considerations  previously  adduced  (CHAP,  xvm.)  in  regard  to  its  effect 
upon  the  processes  of  Nutrition  and  Secretion ;  and  that  such  alterations  are 

1  "On  the  Management  of  Infancy,"  p.  76. 


1012  OF   GENERATION. 

sufficient  to  determine  important  modifications  in  the  developmental  processes 
of  the  Embryo,  to  which  her  blood  furnishes  the  materials,  can  scarcely  admit 
of  a  question,  when  we  recollect  what  an  influence  the  presence  or  absence  of 
particular  substances  has  in  modifying  the  growth  of  parts  in  the  adult  (§  203). 
The  error  of  the  vulgar  notion  on  this  subject,  lies  in  supposing  that  a  sudden 
fright,  speedily  forgotten,  can  exert  such  a  continual  influence  on  the  nutrition 
of  the  Embryo,  as  to  occasion  any  personal  peculiarity.1  The  view  here  stated 
is  one  which  ought  to  have  great  weight,' in  making  manifest  the  importance  of 
careful  management  of  the  health  of  the  Mother,  both  corporeal  and  mental, 
during  the  period  of  pregnancy ;  since  the  constitution  of  the  offspring  so  much 
depends  upon  the  impressions  then  made  upon  its  most  impressible  structure. 

1015.  It  is  frequently  of  great  importance,  both  to  the  Practitioner  and  to 
the  Medical  Jurist,  to  be  able  to  determine  the  age  of  a  Foetus,  from  the  phy- 
sical characters  which  it  presents;  and  the  following  table  has  been  framed  by 
Devergie2  in  order  to  facilitate  such  determination.  It  is  to  be  remarked, 
however,  that  the  absolute  length  and  weight  of  the  Embryo  are  much  less  safe 
criteria,  than  its  degree  of  development,  as  indicated  by  the  relative  evolution  of 
the  several  parts  which  make  their  appearance  successively.  Thus  it  is  very 
possible  for  one  child,  born  at  the  full  time,  to  weigh  less  than  another  born  at 
eight  or  even  at  seven  months;  its  length,  too,  may  be  no  greater:  but  the  posi- 
tion of  the  middle  point  of  the  body  will  usually  afford  sufficient  ground  for  the 
determination;  since,  during  the  two  latter  months  of  pregnancy,  the  increas- 
ing development  of  the  lower  extremities  brings  it  lower  down. 

Embryo  3  to  4  weeks. — It  has  the  form  of  a  serpent;  its  length  from  3  to  5  lines;  its 
head  indicated  by  a  swelling ;  its  caudal  extremity  (in  which  is  seen  a  white  line,  indicat- 
ing the  continuation  of  the  medulla  spinalis),  slender,  and  terminating  in  the  umbilical 
cord ;  the  mouth  indicated  by  a  cleft,  the  eyes  by  two  black  points ;  the  members  begin 
to  appear  as  nipple-like  protuberances ;  the  liver  occupies  the  whole  abdomen ;  the  blad- 
der is  very  large.  The  chorion  is  villous,  but  its  villosities  are  still  diffused  over  the 
whole  surface. 

Embryo  of  6  weeks. — Its  length  from  7  to  10  lines;  its  weight  from  40  to  75  grains; 
face  distinct  from  cranium ;  aperture  of  nose,  mouth,  eyes,  and  ears  perceptible ;  head 
distinct  from  thorax ;  hands  and  forearms  in  the  middle  of  the  length,  fingers  distinct ; 
legs  and  feet  situated  near  the  anus ;  clavicle  and  maxillary  bone  present  a  point  of  ossi- 
fication ;  distinct  umbilicus  for  attachment  of  cord,  which  at  that  time  consists  of  the 
omphalo-meseraic  vessels,  of  a  portion  of  the  urachus,  of  a  part  of  the  intestinal  tube, 
and  of  filaments  which  represent  the  umbilical  vessels.  The  placenta  begins  to  be  form- 
ed ;  the  chorion  still  separated  from  the  amnion ;  the  umbilical  vesicle  very  large. 

Embryo  of  2  months. — Length  from  16  to  19  lines;  weight  from  150  to  300  grains; 
elbows  and  arms  detached  from  the  trunk ;  heels  and  knees  also  isolated ;  rudiments  of 
the  nose  and  of  the  lips ;  palpebral  circle  beginning  to  show  itself ;  clitoris  or  penis  appa- 
rent ;  anus  marked  by  a  dark  spot ;  rudiments  of  lungs,  spleen,  and  suprarenal  capsules ; 
caecum  placed  behind  the  umbilicus ;  digestive  canal  withdrawn  into  the  abdomen ;  ura- 
chus visible ;  osseous  points  in  the  frontal  bone  and  in  the  ribs.  Chorion  commencing  to 
touch  the  amnion  at  the  point  opposite  the  insertion  of  the  placenta;  placenta  begins  to 
assume  its  regular  form ;  umbilical  vessels  commence  twisting. 

Embryo  of  3  months. — Length  from  2  to  2g-  inches;  weight  from  1  oz.  to  1J  oz.  (Troy)  ; 
head  voluminous ;  eyelids  in  contact  by  their  free  margin ;  membrana  pupillaris  visible ; 
mouth  closed ;  fingers  completely  separated ;  inferior  extremities  of  greater  length  than 


'  For  some  valuable  observations  on  this  subject,  see  Montgomery  "  On  the  Signs  of 
Pregnancy." — Numerous  cases  have  been  recorded,  during  the  last  few  years  (especially 
in  the  "  Lancet"  and  "  Provincial  Medical  Journal"),  in  which  malformations  in  the  Infant 
appeared  distinctly  traceable  to  strong  impressions  made  on  the  mind  of  the  Mother  some 
months  previously  to  parturition ;  these  impressions  having  been  persistent  during  the 
remaining  period  of  pregnancy,  and  giving  rise  to  a  full  expectation  on  the  part  of  the 
Mother  that  the  child  would  be  affected  in  the  particular  manner  which  actually  occurred. 

2  "  Medecine  Legale,"  3ieme  edit.  torn.  i.  p.  279. 


DEVELOPMENT  OP  THE  EMBRYO.  1013 

rudimentary  tail;  clitoris  and  penis  very  long ;  thynms  as  well  as  suprarenal  capsules 
present;  caecum  placed  below  the  umbilicus;  cerebrum  5  lines,  cerebellum  4  lines,  me- 
dulla oblongata  1 J  line,  and  medulla  spinalis  f  of  a  line,  in  diameter ;  two  ventricles  of 
heart  distinct.  The  decidua  reflexa  and  decidua  uterina  in  contact ;  funis  contains  um- 
bilical vessels  and  a  little  of  the  gelatine  of  Warthon ;  placenta  completely  isolated ;  umbi- 
lical vesicle,  allantois,  and  omphalo-meseraic  vessels  have  disappeared. 

Foetus  of  4  months. — Length  5  to  6  inches ;  weight  2J  to  3  oz. ;  skin  rosy,  tolerably 
dense ;  mouth  very  large  and  open ;  membrana  pupillaris  very  evident ;  nails  begin  to 
appear ;  genital  organs  and  sex  distinct ;  caecum  placed  near  the  right  kidney ;  gall-blad- 
der appearing ;  meconium  in  duodenum ;  caecal  valve  visible ;  umbilicus  placed  near 
pubis;  ossicula  auditoria  ossified ;  points  of  ossification  in  superior  part  of  sacrum;  mem- 
brane forming  at  point  of  insertion  of  placenta  on  uterus ;  complete  contact  of  chorion 
with  amnion. 

Foetus  o/5  months. — Length  6  to  7  inches;  weight  5  to  7  oz. ;  volume  of  head  still  com- 
paratively great ;  nails  very  distinct ;  hair  beginning  to  appear ;  skin  without  sebaceous 
covering ;  white  substance  in  cerebellum ;  heart  and  kidneys  very  voluminous ;  caecum 
situated  at  inferior  part  of  right  kidney ;  gall-bladder  distinct ;  germs  of  permanent  teeth 
appear;  points  of  ossification  in  pubis  and  calcaneum;  meconium  has  a  yellowish-green 
tint,  and  occupies  commencement  of  large  intestine. 

Foetus  0/6  months. — Length  9  to  10  inches;  weight  1  Ib. ;  skin  presents  some  appear- 
ance of  fibrous  structure ;  eyelids  still  agglutinated,  and  membrana  pupillaris  remains ; 
sacculi  begin  to  appear  in  colon ;  funis  inserted  a  little  above  pubis ;  face  of  a  purplish 
red ;  hair  white  or  silvery ;  sebaceous  covering  begins  to  present  itself ;  meconium  in 
large  intestine ;  liver  of  dark  red ;  gall-bladder  contains  serous  fluid  destitute  of  bitter- 
ness ;  testes  near  kidneys ;  points  of  ossification  in  four  divisions  of  sternum ;  middle 
point  at  lower  end  of  sternum. 

Foetus  of  7  months. — Length  13  to  15  inches ;  weight  3  to  4  Ibs. ;  skin  of  rosy  hue,  thick 
and  fibrous ;  sebaceous  covering  begins  to  appear ;  nails  do  not  yet  reach  extremities 
of  fingers ;  eyelids  no  longer  adherent ;  membrana  pupillaris  disappearing ;  a  point  of 
ossification  in  the  astragalus ;  meconium  occupies  nearly  the  whole  of  large  intestine ; 
valvulae  conniventes  begin  to  appear ;  caecum  placed  in  right  iliac  fossa ;  left  lobe  of  liver 
almost  as  large  as  right ;  gall-bladder  contains  bile ;  brain  possesses  more  consistency ; 
testicles  more  distant  from  kidneys ;  middle  point  at  a  little  below  end  of  sternum. 

Foetus  of  8  months. — Length  14  to  16  inches;  weight  4  or  5  Ibs. ;  skin  covered  with 
well-marked  sebaceous  envelop ;  nails  reach  extremities  of  fingers ;  membrana  pupillaris 
becomes  invisible  during  this  month ;  a  point  of  ossification  in  last  vertebra  of  sacrum ; 
cartilage  of  inferior  extremity  of  femur  presents  no  centre  of  ossification  ;  brain  has  some 
indications  of  convolutions ;  testicles  descend  into  internal  ring ;  middle  point  nearer  the 
umbilicus  than  the  sternum. 

Foetus  o/9  months,  the  full  term. — Length  from  17  to  21  inches;  weight  from  5  to  9  Ibs., 
the  average  probably  about  6|-  Ibs. ;  head  covered  with  hair  in  greater  or  less  quantity,  of 
from  9  to  12  lines  in  length ;  skin  covered  with  sebaceous  matter,  especially  at  bends  of 
joints ;  membrana  pupillaris  no  longer  exists;  external  auditory  meatus  still  cartilaginous; 
four  portions  of  occipital  bone  remain  distinct ;  os  hyoides  not  yet  ossified ;  point  of  ossi- 
fication in  the  centre  of  cartilage  at  lower  extremity  of  femur ;  white  and  gray  substances 
of  brain  become  distinct ;  liver  descends  to  umbilicus ;  testes  have  passed  inguinal  ring, 
and  are  frequently  found  in  the  scrotum ;  meconium  at  termination  of  large  intestine ; 
middle  point  of  body  at  umbilicus,  or  a  little  below  it. 

1016.  Even  at  birth,  there  is  a  manifest  difference  in  the  physical  conditions 
of  infants  of  different  sexes  ;  for,  in  the  average  of  a  large  number,  there  is  a  de- 
cided preponderance  on  the  side  of  the  Males  both  as  to  the  length  and  the 
weight  of  the  body. 

a.  The  length  of  the  body  in  fifty  new-born  infants  of  each  sex,  as  ascertained  by  Que- 
telet,1  was  as  follows  : — 


1  "  Sur  L'Homme,"  torn.  ii.  p.  8. 


1014  OP   GENERATION. 

Males.  Females.  Total. 

From  16  to  17  inches1  (French)         ...       2  4               6 

"      17  to  18           . 8  19  27 

"      18  to  19 28  18  46 

"      19  to  20 12  8  20 

"      20  to  21 0  1              1 

From  these  observations,  the  mean  and  the  extremes  of  the  Lengths  of  the  Male  and 
Female  respectively  were  calculated  to  be — 

Males.  Females. 

Minimum          .         .16  inches,  2  lines  16  inches,  2  lines 

Mean        ...     18  6  &  if 

Maximum         .         .     19  8  20  6 

Notwithstanding  that  the  maximum  is  here  on  the  side  of  the  Female  (this  being  an  acci- 
dental result,  which  would  probably  have  been  otherwise,  had  a  larger  number  been  exa- 
mined) the  average  shows  a  difference  of  4^  lines  in  favor  of  the  Male. 

b.  The  inequality  in  the  Weight  of  the  two  is  even  more  remarkable  ;  the  observations  of 
M.  Quetelet2  were  made  upon  63  male  and  56  female  infants. 

Infants  weighing  from  Males.       Females.         Total. 

1  to  1J  kilog.3 0  1  1 

Ijto2 0  1  1 

2  to2£ 3  7  10 

2£to3 13  14  27 

3  to3A 28  23  51 

3£  to  4 14  7  21 

4  to  4£ 5  3  8 

The  extremes  and  means  were  as  follows  : — 

Males.  Females. 

Minimum 2.34  kilog.  1.12 

Mean 3.20  2.91 

Maximum 4.50  4.25 

c.  The  average  weight  of  infants  of  both  sexes,  as  determined  by  these  inquiries,  is  3.05 
kilog.  or  6.7  Ibs. ;  and  this  corresponds  almost  exactly  with  the  statement  of  Chaussier, 
whose  observations  were  made  upon  more  than  20,000  infants.     The  mean  obtained  by 
him,  without  reference  to  distinction  of  sex,  was  6.75  Ibs. ;  the  maximum  being  11.3  Ibs., 
and  the  minimum  3.2  Ibs.*     The  average  in  this  country  is  probably  rather  higher;  ac- 
cording to  Dr.  Joseph  Clarke,5  whose  inquiries  were  made  on  60  males  and  60  females,  the 
average  of  Male  children  is  7£  Ibs. :   and  that  of  Females  6f  Ibs.     He  adds  that  children 
which  at  the  full  time  weigh  less  than  5  Ibs.  rarely  thrive ;  being  generally  feeble  in  their 
actions,  and  dying  within  a  short  time.     Several  instances  are  on  record,  of  infants  whose 
weight  at  birth  exceeded  15  Ibs.     It  appears  that  healthy  females,  living  in  the  country, 
and  engaged  in  active  but  not  over-fatiguing  occupations,  have  generally  the  largest  child- 
ren ;  and  this  is  what  might  be  expected  d  priori,  from  the  superior  energy  of  their  nutri- 
tive functions. 

1017.  Notwithstanding  that,  in  any  ordinary  population,  there  is  a  decided 
preponderance  in  the  number  of  Females,  the  number  of  Male  birtJis  is  con- 
siderably greater  than  that  of  females.  Taking  the  average  of  the  whole  of 
Europe,  the  proportion  is  about  106  Males  to  100  Females.  It  is  curious, 
however,  that  this  proportion  is  considerably  different  for  legitimate  and  for 
illegitimate  births;  the  average  of  the  latter  being  only  102 J  to  100,  in  the 
places  where  that  of  the  former  was  105f  to  100.  This  is  probably  to  be  ac- 

1  The  French  inch  is  about  one-fifteenth  more  than  the  English. 

2  Op.  cit.  torn.  ii.  p.  35. 

3  The  kilogramme  is  equal  to  2£  Ibs.  avoirdupois. 

4  These  numbers  have  been  erroneously  stated  in  many  Physiological  works ;  owing  to 
the  difference  between  the  French  and  English  pound  not  having  been  allowed  for. 

6  "Philosophical  Transactions,"  vol.  Ixxvi. 


DEVELOPMENT  OP  THE  EMBRYO. 


1015 


counted  for  by  the  fact,  which  is  one  of  the  most  remarkable  contributions  that 
have  yet  been  made  by  Statistics  to  Physiology,  that  the  Sex  of  the  offspring  is 
influenced  by  the  relative  ages  of  the  parents.  The  following  table  expresses 
the  average  results  obtained  by  M.  Hofacker1  in  Germany,  and  by  Mr.  Sadler3 
in  Britain  ;  between  which  it  will  be  seen  that  there  is  a  manifest  correspond- 
ence, although  both  were  drawn  from  a  too  limited  series  of  observations. 
The  numbers  indicate  the  proportion  of  Male  births  to  100  Females,  under  the 
several  conditions  mentioned  in  the  first  column. 


Father  younger  than  Mother 
Father  and  Mother  of  equal  age 
Father  older  by  1  to  6  years 
"          "          6  to  9 
"          "          9  to  18 
"          "         18  and  more 


Hofacker. 

90.6 

90.0 

103.4 

124.7 

143.7 

200.0 


Father  younger  than  Mother 
Father  and  Mother  of  equal  age 
Father  older  by  1  to  6  years 

6  to  11 
11  to  16 
"          "          16  and  more 


Sadler. 

86.5 

94.8 

103.7 

126.7 

147.7 

163.2 


From  this  it  appears,  that  the  more  advanced  age  of  the  Male  parent  has  a  very 
decided  influence  in  occasioning  a  preponderance  in  the  number  of  Male  infants; 
and,  as  the  state  of  society  generally  involves  a  condition  of  this  kind  in  regard 
to  marriages,  whilst  in  the  case  of  illegitimate  children  the  same  does  not  hold 
good,  the  difference  in  the  proportional  number  of  male  births  is  accounted  for. 
We  are  not  likely  to  obtain  data  equally  satisfactory  in  regard  to  the  influence 
of  more  advanced  age  on  the  part  of  the  Female  parent ;  as  a  difference  of  10  or 
15  years  on  that  side  is  not  so  common.  If  it  exist  to  the  same  extent,  it  is 
probable  that  the  same  law  would  be  found  to  prevail  in  regard  to  Female 
children  born  under  such  circumstances,  as  has  been  stated  with  respect  to  the 
Male  ; — namely,  that  the  mortality  is  greater  during  embryonic  life  and  early 
infancy,  so  that  the  preponderance  is  reduced. 

1018.  There  appears  to  be,  from  the  first,  a  difference  in  the  Viability  (or 
probability  of  life)  of  Male  and  Female  children  j  for,  out  of  the  total  number 
born  dead,  there  are  3  Males  to  2  Females  :  this  proportion  gradually  lessens, 
however,  during  early  infancy ;  being  about  4  to  3  during  the  first  two  months, 
and  about  4  to  5  during  the  next  three  months  j  after  which  time  the  deaths  are 
nearly  in  proportion  to  the  numbers  of  the  two  sexes  respectively,  until  the  age 
of  puberty.  The  viability  of  the  two  sexes  continues  to  increase  during  child- 
hood j  and  attains  its  maximum  between  the  13th  and  14th  years.  For  a  short 
time  after  this  epoch  has  been  passed,  the  rate  of  mortality  is  higher  in  Females 
than  in  Males  j  but  from  about  the  age  of  18  to  28,  the  mortality  is  much  greater 
in  Males,  being  at  its  maximum  at  25,  when  the  viability  is  only  half  what  it 
is  at  puberty.  This  fact  is  a  very  striking  one ;  and  shows  most  forcibly  that 
the  indulgence  of  the  passions  not  only  weakens  the  health,  but  in  a  great  num- 
ber of  instances  is  the  cause  of  a  very  premature  death.  From  the  age  of  28 
to  that  of  50,  the  mortality  is  greater  and  the  viability  less  on  the  side  of  the 
Female  ;  this  is  what  would  be  anticipated  from  the  increased  risk  to  which  she 
is  liable  during  the  parturient  period.  After  the  age  of  50,  the  mortality  is 
nearly  the  same  for  both. 

a.  These  facts  have  been  expressed  by  Quetelet  (Op.  cit. )  in  a  form  which  brings  them 
prominently  before  the  eye  (Fig.  277).  The  relative  viability  of  the  male  at  different  ages 
is  represented  by  a  curved  line ;  the  elevation  of  which  indicates  its  degree  at  the  respect- 
ive periods  marked  along  the  base  line.  The  dotted  line,  which  follows  a  different  curve, 
represents  the  viability  of  the  Female.  Starting  from  a,  the  period  of  birth,  we  arrive  at 
the  maximum  of  viability  for  both  at  b ;  from  this  point,  the  Female  curve  steadily  descends 
towards  n,  at  first  very  rapidly,  but  afterwards  more  gradually;  whilst  the  Male  curve  does 
not  quite  descend  so  soon,  but  afterwards  falls  much  lower,  its  minimum  being  c,  which 


'Annales  d'Hygiene,"  Oct.  1829. 


2  "Law  of  Population,"  vol.  ii.  p.  343. 


1016 


OP   GENERATION. 


corresponds  with  the  age  of  25  years.     It  afterwards  ascends  to  d,  which  is  the  maximum 
of  viability  subsequently  to  the  age  of  puberty ;  this  point  is  attained  at  the  age  of  30 

Fig.  277. 


Diagram  representing  the  Comparative  Viability  of  the  Male  and  Female  at  different  Ages. 

years,  from  which  period,  up  to  50,  the  probability  of  life  is  greater  in  the  Male  than  in 
the  Female.     In  the  decline  of  life  there  seems  little  difference  for  the  two  sexes. 

1019.    Similar  diagrams  have  been   constructed   by  Quetelet,  to   indicate 
the  relative  Heights  and  Weights  of  the  two  sexes  at  different  ages  (Fig.  278). 

a.  In  regard  to  Height,  it  may  be  observed  that  the  increase  is  most  rapid  in  the  first 
year,  and  that  it  afterwards  diminishes  gradually;  between  the  ages  of  5  and  16  years, 
the  annual  increase  is  very  regular.     The  difference  between  the  Height  of  the  male  and 
Female,  which  has  been  already  stated  to  present  itself  at  birth,  continues  to  increase 
during  infancy  and  youth;  it  is  not  very  decided,  however,  until  about  the  15th  year,  after 
which  the  growth  of  the  Female  proceeds  at  a  much  diminished  rate,  whilst  that  of  the 
Male  continues  in  nearly  the  same  degree,  until  about  the  age  of  19  years.     It  appears, 
then,  that  the  Female  comes  to  her  full  development,  in  regard  to  Height,  earlier  than  does 
the  Male.     It  seems  probable,  from  the  observations  of  Quetelet,  that  the  full  Height  of 
the  Male  is  not  generally  attained  until  the  age  of  25  years.     At  about  the  age  of  50, 
both  Male  and  Female  undergo  a  diminution  of  their  stature,  which  continues  during  the 
latter  part  of  life. 

b.  The  proportional  Weight  of  the  two  sexes  at  different  periods  corresponds  pretty 
closely  with  their  height.     Starting  from  birth,  the  predominance  then  exhibited  by  the 
Male  gradually  increases  during  the  first  few  years;  but  towards  the  period  of  puberty, 
the  proportional  weight  of  the  Female  increases;  and  at  the  age  of  12  years,  there  is  no 
difference  between  the  two  sexes  in  this  respect.     The  weight  of  the  Male,  however,  then 
increases  much  more  rapidly  than  that   of  the  Female,  especially  between  the  ages  of  15 
and  20  years ;  after  the  latter  period,  there  is  no  considerable  increase  on  the  side  of  the 
Male,  though  his  maximum  is  not  attained  until  the  age  of  40 ;  and  there  is  an  absolute 
diminution  on  the  part  of  the  Female,  whose  weight  remains  less  during  nearly  the  whole 


DEVELOPMENT   OF   THE   EMBRYO. 


1017 


period  of  child-bearing.  After  the  termination  of  the  parturient  period,  the  weight  of  the 
Female  again  undergoes  an  increase,  and  its  maximum  is  attained  about  50.  In  old  age, 
the  weight  of  both  sexes  undergoes  a  diminution  in  nearly  the  same  degree.  The  average 

Fig.  278. 


0          3         70       7J         20       Z5       30  JO  50  6'0  10 

Diagram  representing  the  Comparative  Heights  and  Weights  of  the  Male  and  Female  at  different  Ages. 

Weights  of  the  Male  and  Female,  that  have  attained  their  full  development,  are  twenty 
times  those  of  the  new-born  Infants  of  the  two  sexes  respectively.  The  Heights,  on  the 
other  hand,  are  about  3^  times  as  great. 

1020.  The  chief  differences  in  the  Constitution  of  the  two  sexes  manifest 
themselves  during  the  period  when  the  Generative  function  of  each  is  in  the 
greatest  vigor.  Many  of  these  distinctions  have  been  already  alluded  to ;  but 
there  are  others  of  too  great  importance  to  be  overlooked ;  and  these  chiefly 
relate  to  the  Nervous  System  and  its  functions.  There  is  no  obvious  structural 
difference  in  the  Nervous  System  of  the  two  sexes  (putting  aside  the  local  pecu- 
liarities of  its  distribution  to  the  organs  of  generation),  save  the  inferior  size 
of  the  Cerebral  Hemispheres  in  the  Female.  This  difference,  which  is  not 
observed  in  other  parts  of  the  Encephalon,  is  readily  accounted  for  on  the  prin- 
ciples formerly  stated  (§§  782,  783),  when  we  compare  the  psychical  character 
of  Woman  with  that  of  Man;  for  there  can  be  no  doubt  that — putting  aside  the 
exceptional  cases  which  now  and  then  occur — the  intellectual  powers  of  Woman 
are  inferior  to  those  of  Man.  Although  her  perceptive  faculties  are  more  acute, 
her  capability  of  sustained  mental  exertion  is  much  less ;  and  though  her  views 
are  often  peculiarly  distinguished  by  clearness  and  decision,  they  are  generally 
deficient  in  that  comprehensiveness  which  is  necessary  for  their  stability.  With 
less  of  the  volitional  powers  than  Man  possesses,  she  has  the  emotional  and 
instinctive  in  a  much  stronger  degree.  The  emotions,  therefore,  predominate; 
and  more  frequently  become  the  leading  springs  of  action,  than  they  are  in  Man. 
By  their  direct  influence  upon  the  bodily  frame,  they  produce  changes  in  the 
organic  functions,  which  far  surpass  in  degree  anything  of  the  same  kind  that 
we  ordinarily  witness  in  Man;  and  they  thus  not  unfrequently  occasion 
symptoms  of  an  anomalous  kind,  which  are  very  perplexing  to  the  Medical 
practitioner,  though  very  interesting  to  the  Physiological  observer.  But  they 
also  act  as  powerful  motives  to  the  Will;  and,  when  strongly  called  forth,  pro- 
duce a  degree  of  vigor  and  determination,  which  is  very  surprising  to  those  who 


1018 


OP  GENERATION. 


have  usually  seen  the  individual  under  a  different  aspect.  But  this  vigor,  being 
due  to  the  strong  excitement  of  the  Feelings,  and  not  to  any  inherent  strength 
of  Intellect,  is  only  sustained  during  the  persistence  of  the  motive,  and  fails  as 
soon  as  this  subsides.  The  feelings  of  Woman,  being  frequently  called  forth 
by  the  occurrences  she  witnesses  around  her,  are  naturally  more  disinterested 
than  those  of  Man;  his  energy  is  more  concentrated  upon  one  object;  and  to  this 
his  intellect  is  directed  with  an  earnestness  that  too  frequently  either  blunts 
his  feelings,  or  carries  them  along  in  the  same  channel,  thus  rendering  them 
selfish.  The  intuitive  powers  of  Woman  are  certainly  greater  than  those  of 
Man.  Her  perceptions  are  more  acute,  her  apprehension  quicker;  and  she  has 
a  remarkable  power  of  interpreting  the  feelings  of  others,  which  gives  to  her, 
not  only  a  much  more  ready  sympathy  with  these,  but  that  power  of  guiding 
her  actions  so  as  to  be  in  accordance  with  them,  which  we  call  tact.  This  tact 
bears  a  close  correspondence  with  the  adaptiveness  to  particular  ends,  which  we 
see  in  Instinctive  actions. — In  regard  to  the  inferior  development  of  her  Intel- 
lectual powers,  therefore,  and  in  the  predominance  of  the  Instinctive,  Woman 
must  be  considered  as  ranking  below  Man  ;  but  in  the  superior  purity  and  eleva- 
tion of  her  Feelings,  she  is  as  highly  raised  above  him.  Her  whole  character, 
Psychical  as  well  as  Corporeal,  is  beautifully  adapted  to  supply  what  is  deficient 
in  Man ;  and  to  elevate  and  refine  those  powers,  which  might  otherwise  be  directed 
to  low  and  selfish  objects. 

5. —  Of  Lactation. 

1021.  The  new-born  Infant  in  the  Human  species,  as  in  the  class  of  Mammalia 
generally,  is  supplied  with  nourishment  by  a  secretion  elaborated  from  the  blood 


Fig.  279. 


Fig.  280. 


The  Mammary  Gland  after  the  removal  of  the  skin,  as 
taken  from  the  subject  three  days  after  delivery :  1,  the 
surface  of  the  chest;  2,  subcutaneous  fat;  3,  the  skin 
covering  the  gland ;  4,  circumference  of  the  gland ;  5,  its 
lobules  separated  by  fat ;  6,  the  lactiferous  ducts  converg- 
ing to  unite  in  the  nipple;  7,  the  nipple  slightly  raised, 
and  showing  the  openings  of  the  tubes  at  its  extremity. 


A  vertical  section  of  the  Mammary  Gland, 
showing  its  thickness  and  the  origins  of  the 
lactiferous  ducts :  1,  2,  3,  its  pectoral  sur- 
face ;  4,  section  of  the  skin  on  the  surface  of 
the  gland;  5,  the  thin  skin  covering  the 
nipple ;  6,  the  lobules  and  lobes  composing 
the  gland ;  7,  the  lactiferous  tubes  coming 
from  the  lobules;  8,  the  same  tubes  col- 
lected in  the  nipple. 


of  its  maternal  parent,  by  certain  glandular  organs  known  as  the  Mammary. 
The  structure  of  these,  which  has  been  thoroughly  investigated  by  Sir  A.  Cooper1 


On  the  Anatomy  of  the  Breast,"  1840,  Am.  Ed.  1845. 


OF   LACTATION. 


1019 


and  Mr.  Birket,1  is  extremely  simple.  Each  gland  is  composed  of  a  number  of 
separate  glandules,  which  are  connected  together  by  fibrous  or  fascial  tissue, 
in  such  a  manner  as  to  allow  a  certain  degree  of  mobility  of  its  parts,  one  upon 
another,  which  may  accommodate  them  to  the  actions  of  the  pectoralis  muscle 
whereon  they  are  bound  down ;  and  the  glandules  are  also  connected  by  the 
ramifications  of  the  lactiferous  tubes,  which  intermingle  with  one  another  in 
such  a  manner  as  to  destroy  the  simplicity  and  uniformity  of  their  divisions, 
although  they  rarely  inosculate.  The  mammillary  tubes,  or  terminal  ducts  con* 
tained  in  the  nipple,  are  usually  about  ten  or  twelve  in  number ;  they  are 
straight,  but  of  somewhat  variable  size ;  and  their  orifices,  which  are  situated 
in  the  centre  of  the  nipple,  and  are  usually  concealed  by  the  overlapping  of  its 
sides,  are  narrower  than  the  tubes  themselves.  At  the  base  of  the  nipple,  these 

Fig.  281. 


Distribution  of  the  Milk-ducts  in  the  Mamma  of  the  Human  Female,  during  lactation;  the  ducts  injected 

with  wax. 

tubes  dilate  into  reservoirs,  which  extend  beneath  the  areola  and  to  some  dis- 
tance into  the  gland,  when  the  breast  is  in  a  state  of  lactation.  These  are  much 
larger  in  many  of  the  lower  Mammalia  than  they  are  in  the  Human  female ; 
their  use  is  to  supply  the  immediate  wants  of  the  child  when  it  is  first  applied 
to  the  breast,  so  that  it  shall  not  be  disappointed,  but  shall  be  induced  to  pro- 
ceed with  sucking  until  the  "  draught"  be  occasioned  (§  948).  From  each  of 
these  reservoirs  commence  five  or  six  branches  of  the  lactiferous  tubes,  each  of 
which  speedily  subdivides  into  smaller  ones ;  and  these  again  divaricate,  until 

1  "  The  Diseases  of  the  Breast,  and  their  Treatment,"  1850. 


1020  OP   GENERATION. 

their  size  is  very  much  reduced,  and  their  extent  greatly  increased  (Fig.  281). 
These,  like  the  reservoirs  and  mammillary  tubes,  are  composed  of  a  fibrous  coat 
lined  by  a  mucous  membrane ;  the  latter  is  highly  vascular,  and  forms  a  secre- 
tion of  its  own,  which  sometimes  collects  in  considerable  quantity  when  the  milk 
ceases  to  be  produced.  The  smaller  subdivisions  of  the  lactiferous  tubes  pro- 
ceed to  distinct  lobuli  in  each  glandule  ;  so  that  when  a  branch  of  a  mammary 
tube  has  been  filled  with  injection,  its  attached  lobules,  if  separated  from  each 
other  by  long  maceration,  are  like  a  bunch  of  fruits  clustered  upon  a  stalk  (Fig. 
282).  When  the  lactiferous  tubes  are  pursued  to  their  ultimate  distribution, 
they  are  found  to  terminate  in  follicles,  whose  size,  in  full  lactation,  is  that  of 
a  hole  pricked  in  paper  by  the  point  of  a  very  fine  pin,  so  that  when  distended 
with  quicksilver  or  milk,  they  are  just  visible  to  the  naked  eye ;  at  other  times, 
however,  the  follicles  do  not  admit  of  being  injected,  though  the  lactiferous 

Fig.  282.  Fig.  283. 


Termination  of  portion  of  Milk-  Ultimate  follicles  of  Mammary 

duct  in  a  cluster  of  follicles ;  from  Gland,  with  their  secreting  cells, 

a  mercurial  injection;  enlarged  four  a,  a;  b,  b,  the  nuclei. 


tubes  may  have  been  completely  filled.  They  are  lined  by  a  continuation  of  the 
same  membrane  with  that  which  lines  the  ducts ;  and  this  possesses  a  high  vas- 
cularity.  The  arteries  which  supply  the  glandules  with  blood  become  very 
large  during  lactation  ;  and  their  divisions  spread  themselves  minutely  on  the 
follicles.  From  the  blood  which  they  convey,  the  milk  is  secreted  and  poured 
into  the  follicles,  whence  it  flows  into  the  ducts.  The  inner  surface  of  the  milk- 
follicles,  in  common  with  other  glandular  structures,  is  covered  with  a  layer  of 
epithelium-cells  (Fig.  283),  as  was  first  observed  by  Prof.  Goodsir ;  and  these, 
being  seen  to  contain  milk-globules,  may  without  doubt  be  regarded  as  the  real 
agents  in  the  secreting  process.  Absorbent  vessels  are  seen  to  arise  in  large 
numbers  in  the  neighborhood  of  the  follicles ;  their  function  appears  to  be  to 
absorb  the  more  watery  part  of  the  milk  contained  in  the  follicles  and  tubes,  so 
as  to  render  it  more  nutrient  than  it  is  when  first  secreted  ;  and  also  to  relieve 
the  distension  which  would  occur,  during  the  absence  of  the  child,  from  the 
continuance  of  the  secreting  process. — The  Mammary  gland  may  be  detected  at  an 
early  period  of  foetal  existence ;  being  easily  distinguishable  from  the  surround- 
ing parts  by  the  redness  of  its  color  and  its  high  vascularity,  especially  when 
the  whole  is  injected.  At  this  period,  it  presents  no  difference  in  the  male 
and  female ;  and  it  is  not  until  near  the  period  of  puberty  that  any  striking 
change  manifests  itself,  the  gland  continuing  to  grow,  in  the  one  sex  as  in  the 
other,  in  proportion  to  the  body  at  large.  At  about  the  age  of  thirteen  years, 
however,  the  enlargement  of  the  gland  commences  in  the  Female  \  and  by  six- 
teen, it  is  greatly  evolved,  and  some  of  the  lactiferous  tubes  can  be  injected. 
At  about  the  age  of  twenty,  the  gland  attains  its  full  size  previous  to  lactation ; 
but  the  milk-follicles  cannot  even  then  be  injected  from  the  tubes.  During 
pregnancy,  the  mammae  receive  a  greatly  increased  quantity  of  blood.  This 
determination  often  commences  very  early,  and  produces  a  feeling  of  tenderness 
and  distension,  which  is  a  valuable  sign  (where  it  exists  in  connection  with 


OP   LACTATION.  1021 

others)  of  the  commencement  of  gestation.  The  Areola  at  this  time  becomes 
darker  in  its  color,  and  thicker  in  substance,  and  also  more  extended ;  its  pa- 
pillae become  more  developed,  and  the  secretion  from  its  follicles  increases.  A 
true  lacteal  secretion  usually  commences  about  the  third  or  fourth  month  of 
pregnancy,  and  may  be  obtained  by  pressure  properly  applied.  This  fact  may 
be  usefully  applied  in  diagnosing  cases  of  concealed  or  doubtful  pregnancy  from 
cases  of  simple  suppression  of  the  catamenia;  but  it  will  not  serve  to  distinguish 
true  pregnancy  from  spurious,  or  from  the  distension  of  the  uterus  by  tumors.1 
The  vascularity  of  the  gland  continues  to  increase  during  pregnancy;  and  at  the 
time  of  parturition,  its  lobulated  character  can  be  distinctly  felt.  The  follicles  are 
not,  however,  developed  sufficiently  for  injection,  until  lactation  has  commenced. 
After  the  cessation  of  the  catamenia  from  age,  so  that  pregnancy  is  no  longer 
possible,  the  lactiferous  ducts  continue  open,  but  the  milk-follicles  are  incapable 
of  receiving  injection.  The  substance  of  the  glandules  gradually  disappears, 
so  that  in  old  age  only  portions  of  the  ducts  remain,  which  are  usually  loaded 
with  mucus  j  but  the  place  of  the  glandules  is  commonly  filled  up  by  adipose 
tissue,  so  that  the  form  of  the  breast  is  preserved.  Sir  A.  Cooper  notices  a 
curious  change,  which  he  states  to  be  almost  invariable  with  age ;  namely,  the 
ossification  of  the  arteries  of  the  breast,  the  large  trunks  as  well  as  the  branches, 
so  that  their  calibre  is  greatly  diminished  or  even  obliterated. — The  Mammary 
gland  of  the  Male  is  a  sort  of  miniature  picture  of  that  of  the  Female.  It 
varies  extremely  in  its  magnitude,  being  in  some  persons  of  the  size  of  a  large 
pea ;  whilst  in  others  it  is  an  inch,  or  even  two  inches,  in  diameter.  In  its 
structure  it  corresponds  exactly  with  that  of  the  female,  but  is  altogether  on  a 
smaller  scale.  It  is  composed  of  lobules  containing  follicles  from  which  ducts 
arise ;  and  these  follicles  and  ducts  are  not  too  minute  to  be  injected,  although 
with  difficulty.  The  evolution  of  the  gland  goes  on  pari  passu  with  that  of 
the  body,  not  undergoing  an  increase  at  any  particular  period ;  it  is  sometimes 
of  considerable  size  in  old  age.  A  fluid,  which  is  probably  mucus,  may  be 
pressed  from  the  nipple  in  many  persons ;  and  this  in  the  dead  body  with 
even  more  facility  than  in  the  living.  That  the  essential  character  of  the  gland  is 
the  same  in  the  male  as  in  the  female,  is  shown  by  the  instances,  of  which  there 
are  now  several  on  record,  in  which  infants  have  been  suckled  by  men  (§  1022). 
1022.  Although  the  state  of  functional  activity  in  the  Mammary  gland  is 
usually  limited  to  the  epoch  succeeding  Parturition,  yet  this  is  not  invariably 
the  case  ;  for  numerous  instances  are  on  record,  in  which  young  women  who 
have  never  borne  children,  and  even  old  women  long  past  the  period  of 
child-bearing,  have  had  such  a  copious  flow  of  milk  as  to  be  able  to  act  as  effi- 
cient nurses.3  In  these  cases,  the  strong  desire  to  furnish  milk,  and  continued 
irritation  of  the  nipple  by  the  infant's  mouth  seem  to  have  furnished  the  stimu- 
lus requisite  for  the  formation  of  the  secretion ;  and  it  has  been  found  that 
this  is  usually  adequate  to  restore  the  secretion,  after  it  has  been  intermitted  for 
some  months  during  the  ordinary  period  of  lactation,  in  consequence  of  disorder 
or  debility  on  the  part  of  the  mother,  or  any  other  cause ;  so  that  where  her  con- 
dition renders  it  advisable  that  she  should  discontinue  nursing  for  a  time,  the 
child  may  be  withdrawn  and  the  milk  "  dried-up"  with  a  confident  expectation 
that  the  secretion  may  be  reproduced  subsequently.3  Dr.  M' William  mentions, 
in  his  Report  of  the  Niger  Expedition,4  that  the  inhabitants  of  Bona  Yista  (Cape 

1  See  the  valuable  paper  by  Dr.  Peddie,  "  On  the  Mammary  Secretion,"  in  the  "  Edinb. 
Monthly  Journ.,"  Aug.  1848. 

2  A  collection  of  such  cases  is  given  in  Dr.  Dunglison's  "Human  Physiology,"  7th  edit, 
vol.  ii.  p.  513. 

3  See  an  account  of  M.  Trousseau's  experience  on  this  point,  in  "L'Union  Medicale," 
1852,  No.  7  ;  and  a  paper  by  Dr.  Ballou  in  the  "  Amer.  Journ.  of  Med.  Sci.,"  Jan.  1852. 

«  "  Medical  Gazette,"  Jan.  1847. 


1022  OP   GENERATION. 

de  Verde  Islands)  are  accustomed  to  provide  a  wet-nurse  in  cases  of  emergency, 
in  the  person  of  any  woman  who  has  once  borne  a  child  and  is  still  within  the 
age  of  child-bearing,  by  continued  fomentation  of  the  mammse  with  a  decoction 
of  the  leaves  of  ihejatropha  curcas,  and  by  suction  of  the  nipple.  The  most 
curious  fact,  however,  is  that  even  Men  should  occasionally  be  able  to  perform 
the  duties  of  nurses,  and  should  afford  an  adequate  supply  of  infantile  nutri- 
ment. Several  cases  of  this  kind  are  upon  record  j1  but  one  of  the  most  recent 
and  authentic  is  that  given  by  Dr.  Dunglison.3  "  Professor  Hall,  of  the  Uni- 
versity of  Maryland,  exhibited  to  his  Obstetrical  class,  in  the  year  1837,  a  colored 
man,  fifty-five  years  of  age,  who  had  large,  soft,  well-formed  mammae,  rather 
more  conical  than  those  of  the  female,  and  projecting  fully  seven  inches  from 
the  chest ;  with  perfect  and  large  nipples.  The  glandular  structure  seemed  to 
the  touch  to  be  exactly  like  that  of  the  female.  This  man  had  officiated  as  wet- 
nurse,  for  several  years,  in  the  family  of  his  mistress ;  and  he  represented  that 
the  secretion  of  milk  was  induced  by  applying  the  children  intrusted  to  his 
care  to  the  breasts  during  the  night.  When  the  milk  was  no  longer  required, 
great  difficulty  was  experienced  in  arresting  the  secretion.  His  genital  organs 
were  fully  developed." — Corresponding  facts  are  also  recorded  of  the  male  of 
several  of  the  lower  animals. 

1023.  The  secretion  of  Milk  consists  of  Water  holding  in  solution  Sugar, 
various  Saline  ingredients,  and  the  peculiar  albuminous  substance  termed  Casein  • 
and  having  Oleaginous  particles  suspended  in  it.  The  constitution  of  this  fluid 
is  made  evident  by  the  ordinary  processes  to  which  it  is  subjected  in  domestic 
economy.  If  it  be  allowed  to  stand  for  some  time,  exposed  to  the  air,  a  large 
part  of  the  oleaginous  globules  come  to  the  surface,  being  of  less  specific 
gravity  than  the  fluid  through  which  they  are  diffused.  At  the  same  time,  there 
is  reason  to  believe  that  they  undergo  a  change,  which  will  be  presently  de- 
scribed. The  cream  thus  formed  does  not,  however,  consist  of  oily  particles 
alone ;  but  includes  a  considerable  amount  of  casein,  with  the  sugar  and  salts  of 
the  milk.  These  are  further  separated  by  the  continued  agitation  of  the  cream ; 
which,  by  rupturing  the  envelops  of  the  oil-globules,  separates  it  into  butter, 
formed  by  their  aggregation,  and  buttermilk,  containing  the  casein,  sugar,  &c. 
A  considerable  quantity  of  casein,  however,  is  entangled  with  the  oleaginous 
matter,  and  this  has  a  tendency  to  decompose  so  as  to  render  the  butter  rancid ; 
it  may  be  separated  by  keeping  the  butter  melted  at  the  temperature  of  180°, 
when  the  casein  will  fall  to  the  bottom,  leaving  the  butter  pure,  and  much  less 
liable  to  change. — The  milk,  after  the  cream  has  been  removed,  still  contains 
the  greatest  part  of  its  casein  and  sugar.  If  it  be  kept  long  enough,  a  spon- 
taneous change  takes  place  in  its  composition  ;  the  sugar  is  converted  in  to  lactic 
acid,  and  this  coagulates  the  casein,  precipitating  it  in  small  flakes.  The  same 
precipitation  may  be  accomplished  at  any  time  by  the  addition  of  an  acid ;  all 
the  acids,  however,  which  act  upon  albumen,  do  not  precipitate  casein,  as  will 
presently  be  pointed  out  in  detail ;  the  most  effectual  is  that  contained  in  the 
dried  stomach  of  a  calf,  known  as  rennet.  The  whey  left  after  the  curd  has 
been  separated  contains  a  large  proportion  of  the  saccharine  and  saline  matter 

1  See  the  case  described  by  the  Bishop  of  Cork,  in  the  "Philosophical  Transactions," 
vol.  xli.  p.  813;  one  mentioned  by  Captain  Franklin   ("Narrative  of  a  Journey  to  the 
Polar  Sea,"  p.  157) ;  and  one  which  fell  under  the  notice  of  the  celebrated  traveller  Hum- 
boldt  ("  Personal  Narrative,"  vol.  iii.  p.  58). 

2  "Human  Physiology,"  7th  edit.  vol.  ii.  p.  514. — Dr.  Dunglison  also  mentions  that  in 
the  winter  of  1849-50,  an  athletic  man,  twenty-two  years  of  age,  presented  himself  at  the 
Jefferson  Medical  College  at  Philadelphia,  whose  left  mamma,  without  any  assignable  cause, 
became  greatly  developed,  and  secreted  milk  copiously.     [Reported  in  "Philada.  Medical 
Examiner,"  Aug.  1850. — ED.] — It  may  be  added  that  a  lactescent  fluid,  apparently  pre- 
senting the  characters  of  true  milk,  may  frequently  be  expressed  from  the  mammary 
glands  of  infants.     (See  "Dublin  Medical  Press,"  April  17,  1850.) 


OF   LACTATION.  1023 

that  entered  into  the  original  composition  of  the  milk  ;  this  may  be  readily 
separated  by  evaporation. — When  Milk  is  examined  with  the  Microscope,  it  is 
seen  to  contain  a  large  number  of  particles  of  irregular  size  and  form,  suspended 
in  a  somewhat  turbid  fluid ;  these  particles  vary  in  size  from  about  the  1-12, 700th 
to  the  1 -3040th  of  an  inch ;  and  they  are  termed  "  milk-globules."  They  are 
not  affected  by  the  mere  contact  of  ether  or  alkalies ;  but  if  these  reagents  are 
shaken  with  them,  an  immediate  solution  is  the  result.  The  same  effect  happens 
if  they  are  first  treated  with  acetic  acid.  Hence  it  is  evident  that  the  globules 
consist  of  oily  matter,  inclosed  in  an  envelop  of  some  kind :  and  an  extremely 
delicate  pellicle  may  in  fact  be  distinguished,  after  the  removal  of  the  oily 
matter  by  ether,  or  after  the  globules  have  been  ruptured  and  their  contents 
pressed  out  by  rubbing  a  drop  of  milk  between  two  plates  of  glass.  No  proof 
of  the  organization  of  this  pellicle  has,  however,  been  detected ;  and  it  is  probably 
to  be  regarded  as  the  simple  result  of  the  contact  of  oil  with  albuminous  matter 
(§  42). — Besides  these  milk-globules,  other  globules  of  much  smaller  size  are  seen 
in  milk ;  and  these  present  the  peculiar  movement  which  is  exhibited  by  mole- 
cules in  general.  Most  of  them  seem  to  consist  of  oily  matter  not  inclosed  in  an 
envelop,  as  they  are  at  once  dissolved  when  the  fluid  is  treated  with  ether ; 
but,  according  to  the  statements  of  Donne,  it  would  seem  that  a  portion  of  them 
are  composed  of  casein,  suspended,  not  dissolved,  in  the  fluid.  In  addition  to 
the  foregoing  particles,  there  are  found  in  the  Colostrum,  or  milk  first  secreted 
after  delivery,  large  yellow  granulated  corpuscles,  which  seem  to  be  composed 
of  a  multitude  of  small  grains  aggregated  together ;  these  appear  to  be  chiefly 
of  a  fatty  nature,  being  for  the  most  part  soluble  in  ether ;  but  traces  of  some 
adhesive  matter,  probably  mucus,  holding  together  the  particles,  are  then  seen. 
They  are  considered  by  some  as  "  exudation-corpuscles,"  to  which  they  certainly 
bear  a  close  resemblance ;  according  to  Reinhardt,  they  are  transformations  of 
the  epithelial  cells  of  the  mammary  ducts,  the  result  of  a  sort  of  fatty  degene- 
ration or  regressive  metamorphosis  consequent  upon  the  peculiar  activity  of  the 
mammary  gland  during  pregnancy.1  Lamellae  of  epithelium  are  also  found  in 
the  milk. — All  the  larger  globules  may  be  removed  by  repeated  filtration ;  and 
the  fluid  is  then  nearly  transparent.  This,  in  fact,  is  the  simplest  way  of  sepa- 
rating the  oleaginous  from  the  other  constituents  of  the  milk;  as  but  little 
casein  then  adheres  to  the  former.  That  the  transparent  fluid  which  has  passed 
through  the  filter  contains  nearly  the  whole  amount  of  the  casein  of  the  milk, 
appears  a  sufficient  proof  that  this  is,  for  the  most  part,  truly  dissolved  in  the 
fluid. 

1024.  "We  shall  now  consider  the  chemical  characters  of  each  of  the  fore- 
going ingredients. — The  Oleaginous  matter  of  milk  principally  consists  of  the 
ordinary  components  of  fat  (§  37) ;  but  it  also  contains  another  substance  pecu- 
liar to  it,  designated  as  butyrin,  to  which  the  peculiar  smell  and  taste  of  butter 
are  due;  this  yields  in  saponification  three  volatile  acids,  of  strong  animal  odor, 
to  which  Chevreul  has  given  the  names  of  butyric,  caproic,  and  capric  acids. 
These  peculiar  acids  are  not  only  formed  when  the  butyrin  is  treated  with  alka- 
lies, but  are  produced  by  the  ordinary  decomposition  of  this  principle,  which  is 
favored  by  time  and  moderate  warmth. — The  Casein  of  Human  milk,  however, 
is  usually  said  to  be  much  less  precipitable  by  acids  than  is  that  of  the  Cow ; 
very  commonly  resisting  the  action  of  the  mineral  acids,  and  even  that  of  the 
acetic,  but  being  always  coagulated  by  rennet,  though  the  curd  is  long  in  col- 
lecting. On  this  point,  however,  there  has  been  much  discrepancy  of  statement, 
on  which  the  recent  experiments  of  Mr.  Moore2  throw  some  light.  It  appears, 
from  the  results  obtained  by  him,  that  Human  Milk  forms  with  most  acids  two 

1  See  an  abstract  of  his  views  in  the  "Edinb.  Monthly  Journal"  for  Feb.  1848. 

2  "Dublin  Quarterly  Journal  of  Medical  Science,"  vol.  vii.  p.  280. 


1024  OF   GENERATION. 

sets  of  compounds,  one  of  them  soluble  in  water,  the  other  insoluble ;  the  latter 
being  formed  only  when  the  quantity  of  acid  is  large  in  proportion  to  the  casein. 
Thus,  when  two  fluid  ounces  of  Cow's  milk  were  boiled  with  a  single  drop  of 
nitric  acid,  complete  coagulation  of  the  casein  at  once  took  place  :  but  when  two 
fluid  drachms  of  Human  milk  were  treated  in  the  same  manner,  no  coagulation 
occurred,  though  the  casein  was  at  once  thrown  down  by  a  solution  of  lerrocy- 
anide  of  potassium;  the  same  quantity  of  milk,  with  five  drops  of  the  acid, 
formed  a  coagulum  which  was  not  very  manifest  until  after  the  lapse  of  five 
hours,  but  was  very  complete,  the  serous  fluid  not  being  found  to  contain  any 
casein  by  testing  it  with  ferrocyanide  of  potassium ;  and  it  required  ten  drops 
of  nitric  acid  to  produce  immediate  coagulation. — The  quantity  of  acid  necessary 
to  produce  coagulation  sufficiently  rapid  to  be  immediately  visible  will  vary  with 
the  amount  of  casein  present  in  the  particular  specimen  of  milk,  5  drops  in  some 
instances  producing  a  coagulation  as  rapid  as  that  produced  by  10  drops  in 
others.  In  no  specimen  did  Mr.  Moore  fail  to  produce  coagulation  by  adding 
a  sufficiency  of  acid.  Acetic  acid  without  heat  produces  in  Human  milk  a 
slow  separation  of  soft  flaky  coagula ;  but,  when  heat  is  employed,  a  more  perfect 
coagulation  is  produced  by  small  than  by  large  quantities  of  this  acid.  Rennet 
does  not  seem  to  act  upon  the  casein  of  Human  milk,  unless  an  acid  be  also 
present.  In  several  of  these  particulars,  as  well  as  in  its  small  proportional 
amount,  the  Casein  of  Ass's  milk  bears  a  closer  resemblance  to  that  of  Human 
milk  than  does  that  of  the  Cow. — The  Sugar  of  Milk,  which  may  be  obtained 
by  evaporating  whey  to  the  consistence  of  a  syrup,  and  then  setting  it  aside  to  crys- 
tallize, forms  opaque  prisms  or  rhombohedra,  whose  composition  is  10C,8H, 
80 -f  2HO.  In  many  of  its  properties  it  bears  a  close  resemblance  to  Glucose 
(§  45),  into  which  it  is  readily  converted  by  the  agency  of  dilute  sulphuric  or 
hydrochloric  acid,  or  by  the  acetic  or  citric  acids.  It  is  readily  made  to  pass 
into  the  lactic  and  butyric  fermentation,  by  the  appropriate  ferments ;  but  is 
with  difficulty  brought  to  undergo  the  vinous  fermentation. — The  Saline  matter 
contained  in  milk  appears  to  be  nearly  identical  with  that  of  the  blood ;  with  a 
larger  proportion  of  the  phosphates  of  lime  and  magnesia,  which  amount  to  2  or 
2£  parts  in  1000.  These  phosphates  are  held  in  solution  chiefly  by  the  casein, 
which  seems  to  have  a  power  of  combining  with  them,  even  greater  than  that 
of  albumen :  the  presence  of  a  minute  proportion  of  free  alkali,  also,  assists  their 
solution.  A  small  portion  of  iron  in  the  state  of  phosphate,  together  with  the 
chlorides  of  potassium  and  sodium,  may  also  be  detected  in  milk.1 

1025.  The  proportion  of  these  different  constituents  is  liable  to  great  varia- 
tion, from  several  causes.  Thus,  the  whole  amount  of  the  solid  constituents 
may  vary  from  86  to  138.6  parts  in  1000 ;  the  difference  being  partly  due  to 
individual  constitution,  but  in  great  part,  also,  to  the  amount  and  character  of 
the  ingesta.  The  average  seems  to  be  between  100  and  120  parts.  The  follow- 
ing are  the  results  of  the  analyses  of  Simon  ;  the  first  column  being  the  average 
of  fourteen  observations  upon  the  same  woman ;  the  second  giving  the  maxi- 
mum of  each  ingredient ;  and  the  third  the  minimum : — 

i.  ii.  in. 

Water 883.6  914.0  861.4 

Butter 25.3  54.0  8.0 

Casein 34.3  45.2  19.6 

Sugar  of  Milk  and  extractive  matters  .         .             48.2  62.4  39.2 

Fixed  salts 2.3  2.7  1.6 

It  also  appears,  from  the  analyses  of  Simon,  that  the  proportion  of  the  different 
ingredients  is  liable  to  variation,  according  to  the  time  which  has  elapsed  since 
parturition.  The  quantity  of  Casein  is  at  its  minimum  at  the  commencement  of 

1  Haidlen  in  "  Annalen  der  Chemie  und  Pharmacie,"  band  xlv.  p.  263. 


OF   LACTATION.  1025 

lactation,  and  then  gradually  rises  until  it  attains  a  nearly  fixed  proportion. 
The  quantity  of  Sugar,  on  the  contrary,  is  at  its  maximum  at  first,  and  gradually 
diminishes.  The  amount  of  Butter  (as  appears  from  the  wide  extremes  shown 
in  the  above  tables)  is  more  variable  than  that  of  any  other  constituent. — That 
some  of  the  variations  are  due,  moreover,  to  the  character  of  the  ingesta,  and 
others  to  the  external  temperature,  amount  of  exercise,  and  other  circumstances 
affecting  the  individual,  is  proved  by  the  inquiries  of  Dr.  Playfair  upon  the 
Milk  of  the  Cow.  He  has  shown  that  the  amount  of  butter  depends  in  part 
upon  the  quantity  of  oily  matter  in  the  food,  and  in  part  upon  the  amount  of 
exercise  which  the  animal  takes,  and  the  warmth  of  the  atmosphere  in  which  it 
is  kept :  exercise  and  cold,  by  increasing  the  respiration,  eliminate  part  of  the 
oily  matter  in  the  form  of  carbonic  acid  and  water ;  whilst  rest  and  warmth,  by 
diminishing  this  drain,  favor  its  passage  into  the  milk.  The  proportion  of 
Casein,  on  the  other  hand,  is  increased  by  exercise.  Dr.  Playfair's  experience 
on  this  head  seems  to  correspond  with  the  results  of  common  observation  in 
Switzerland ;  for  where  the  cattle  pasture  in  very  exposed  situations,  and  are 
obliged  to  use  a  great  deal  of  muscular  exertion,  the  quantity  of  butter  yielded 
by  them  is  very  small,  whilst  the  cheese  is  in  unusually  large  proportion ;  but 
these  very  cattle,  when  stall-fed,  give  a  large  quantity  of  butter  and  very  little 
cheese. 

1026.  The  change  which  naturally  takes  place,  from  the  condition  of  Colos- 
trum to  that  of  true  Milk,  during  the  first  week  of  lactation,  is  a  very  import- 
ant one.  The  Colostrum  has  a  purgative  effect  upon  the  child,  which  is  very 
useful  in  clearing  its  bowels  of  the  meconium  that  loads  them  at  birth  ;  and  thus 
the  necessity  of  any  other  purgative  is  generally  superseded.  Occasionally, 
however,  the  colostric  character  is  retained  by  the  milk,  during  an  abnormally 
long  period ;  and  the  health  of  the  infant  is  then  severely  affected.  It  is  im- 
portant to  know  that  this  may  occur,  even  though  the  milk  may  present  all  the 
usual  appearance  of  the  healthy  secretion ;  but  the  microscope  at  once  detects 
the  difference.1  The  return  to  the  character  of  the  early  milk,  which  has  been 
stated  to  take  place  after  the  expiration  of  about  twelve  months,  seems  to  indi- 
cate that  Nature  designs  the  secretion  no  longer  to  be  encouraged.  The  mother's 
milk  cannot  then  be  so  nutritious  to  the  child  as  other  food;3  and  every  medical 
man  is  familiar  with  the  injurious  consequences  to  which  she  renders  herself 
liable,  by  unduly  prolonging  lactation.3  Cases  are  not  unfrequent,  however,  in 
which  the  secretion  continues  as  long  as  there  is  a  demand  for  it ;  and  sometimes 
quite  independently  of  this.  It  is  the  habit,  among  some  nations,  to  suckle 
the  children  until  they  are  three  or  four  years  old,  and  to  continue  doing  so  even 
though  another  pregnancy  should  supervene  ;4  so  that  the  older  child  is  only  dis- 
placed by  the  arrival  of  another  infant.  And  it  seems  to  be  chiefly  among  those 
who  have  thus  forced  the  mammary  gland  into  a  state  of  unnaturally  persistent 
activity,  that  the  spontaneous  and  irrepressible  flow  continues,  after  the  demand 
for  it  has  ceased.5 

1  See  Donne,  "  Du  Lait,  et  en particulier  celui  des  Nourrices,"  and  "  Brit,  and  For.  Med. 
Review,"  vol.  vi.  p.  181. 

2  On  the  whole  subject  of  Infant  Nutrition,  the  Author  would  strongly  recommend  the 
excellent  little  work  of  Dr.  A.  Combe,  formerly  referred  to. 

3  One  of  these,  which  has  particularly  fallen  under  the  Author's  notice,  is  debility  of  the 
retina,  sometimes  proceeding  to  complete  amaurosis :  this,  if  treated  in  time,  is  most  com- 
monly relieved  by  discontinuance  of  lactation,  generous  diet,  and  quinine. 

4  See  Erman's  "  Travels  in  Siberia"    (translated  by  Cooley),  vol.  ii.  p.  527  ;  and  the 
"Narrative  of  the  United  States'  Exploring  Expedition,"  vol.  ii.  p.  138. 

5  Thus  Dr.  Green  has  published  ("  New  York  Journ.  of  Med.  and  Surg.,"  Sept.  1844) 
the  case  of  a  lady,  aet.  47,  the  mother  of  four  children,  who  had  an  abundant  supply  of 
milk  for  twenty-seven  years  previously.     A  period  of  exactly  four  years  and  a  half  occurred 

65 


1026  OF    GENERATION. 

1027.  It  is  very  interesting  to  observe  that  Milk  contains  the  three  classes  of 
principles  which  are  required  for  human  food — the  Albuminous,  the  Oleaginous, 
and  the  Saccharine  ;  and  it  is  the  only  secreted  fluid  in  which  these  all  exist  to  any 
considerable  amount.     It  is,  therefore,  the  food  most  perfectly  adapted  for  the 
young  animal ;   and  is  the  only  single  article  supplied  by  nature  in  which  such 
a  combination  exists.     Our  artificial  combinations  will  be  suitable  to  replace  it, 
just  in  proportion  as  they  imitate  its  character;  but  in  none  of  them  can  we 
advantageously  dispense  with  milk,  under  some  form  or  other.     It  should  be 
remembered  that  the  Saline  ingredients  of  milk,  especially  the  phosphates  of 
lime,  magnesia,  and  iron,  have  a  very  important  function  in  the  nutrition  of  the 
infant,  affording  the  material  for  the  consolidation  of  its  bones  and  for  the  pro- 
duction of  its  red  blood-corpuscles ;  and  any  fluid  substituted  for  milk,  which 
does  not  contain  these,  is  deficient  in  essential  constituents.     It  is  very  justly 
remarked  by  Dr.  Rees,1  that,  of  all  the  secreted  fluids,  Milk  is  most  nearly  allied 
in  its  composition  to  Blood. 

1028.  The  proportion  of  the  different  ingredients  in  the  Milk  of  different 
animals,  is  subject  to  considerable  variation  ;  and  this  fact  is  of  much  practical 
importance  in  guiding  our  selection,  when  good  Human  milk  cannot  be  con- 
veniently obtained  for  the  nourishment  of  an  infant.     The  first  point  to  be  in- 
quired into,  is  the  quantity  of  solid  matter  contained  in  each  kind ;  this  may  be 
determined  either  by  evaporation,  or  by  the  specific  gravity  of  the  fluid.     The 
Specific  Gravity  of  Human  milk  is  stated  by  Dr.  Rees  (loc.  cit.)  to  vary  between 
1030  and  1035 ;  others,  however,  have  estimated  it  much  lower.     That  of  the 
Cow  appears  to  be  usually  about  the  same;  that  of  the  cream,  however,  being 
1024,  and  that  of  the  skimmed  milk  about  1035.     The  variation  will  in  part 
depend  (as  in  the  case  of  the  urine)  upon  the  quantity  of  fluid  ingested,  and  in 
part,  it  is  probable,  upon  the  manner  in  which  the  milk  is  drawn ;  for  it  is  well 
known  to  milkers,  that  the  last  milk  they  obtain  is  much  richer  than  that  with 
which  the  udder  is  distended  at  the  commencement.     The  quantity  of  solid 
matter  obtainable  from  Human  and  from  Cow's  Milk  by  evaporation,  seems,  like 
the  specific  gravities  of  the  fluids,  to  be  nearly  the  same.     In  the  relative  pro- 
portion of  the  ingredients,  however,  there  is  a  considerable  difference ;   there 
being  much  more  sugar  and  less  casein  in  Human  Milk,  than  in  that  of  the  Cow. 
The  following  table  exhibits  the  relative  proportions  of  the  different  ingredients, 
in  the  Milk  of  various  animals,  from  which  that  fluid  is  commonly  obtained : — 

Cow.  Goat.  Sheep.  Ass.  Mare. 

Water 861.0         868.0         856.2        907.0          896.3 

Butter 

Casein    ...... 

Sugar  of  Milk  and  extractive  matters 
Fixed  salts 


38.0          33.2  42.0          12.10        traces 

68.0          40.2  45.0          16.74          16.2 


29.0          52.8  50.0  \ 

6.1  5.8  6.8  / 


62.31          87.5 


It  appears  from  this,  that,  whilst  the  milks  of  the  Cow,  G-oat,  and  Sheep  do  not 
differ  from  each  other  in  any  very  prominent  degree,  that  of  the  Ass  and  Mare 
is  a  fluid  of  very  dissimilar  character,  containing  a  comparatively  small  propor- 
tion of  casein,  and  scarcely  any  butter,  but  abounding  in  sugar.  Hence  it  is, 
that  it  is  much  more  disposed  to  ferment  than  other  milk;  indeed  the  sugar  of 
mare's  milk  is  so  abundant,  that  the  Tartars  prepare  from  it  a  spirituous  liquor, 
to  which  they  give  the  name  of  koumiss.  It  would  further  appear  that  no  milk 
more  nearly  approaches  that  of  the  Human  female,  in  the  proportion  of  its 
ingredients,  than  that  of  the  Sheep  and  Groat;  these  both  possess,  however,  a 

between  each  birth,  and  the  children  were  permitted  to  take  the  breast  until  they  were 
running  about  at  play.     At  the  time  when  Dr.  G.  wrote,  she  had  been  nine  years  a  widow, 
and  was  obliged  to  have  her  breasts  drawn  daily,  the  secretion  of  milk  being  so  copious. 
1  "Cyclopcedia  of  Anatomy  and  Physiology,"  Art.  "Milk." 


OF   LACTATION.  1027 

larger  amount  of  casein,  which  forms  a  peculiarly  dense  curd ;  and  the  milk  of 
the  goat  is  tainted  with  the  peculiar  odor  of  the  animal,  which  is  more  intense 
if  the  individual  be  dark  colored.  The  milk  of  the  Ass,  though  differing  in  the 
proportion  of  its  ingredients,  seems  to  bear  a  closer  approximation  in  properties 
(§  1024).  The  milk  of  the  Cow  will  usually  answer  very  well  for  the  food  of 
the  infant ;  care  being  taken  to  dilute  it  properly,  according  to  the  age  of  the 
child,  and  to  add  a  little  sugar.  Where  there  is  an  apprehension  of  an  early 
failure  in  the  supply  of  Milk,  the  Author  has  found  it  advantageous  to  com- 
mence feeding  the  infant  once  a  day  with  this  mixture,  soon  after  the  first  month ; 
and  the  number  of  its  meals  may  be  progressively  increased,  until  it  becomes 
entirely  independent  of  its  parent,  without  any  abrupt  transition. 

1029.  From  what  has  been  stated  of  the  close  correspondence  between  the 
elements  of  the  Blood  and  those  of  the  Milk,  it  is  evident  that  we  can  scarcely 
expect  to  trace  the  existence  of  the  latter,  as  such,  in  the  circulating  fluid.  To 
what  degree  the  change  in  which  their  elaboration  consists  is  accomplished  in 
the  Mammary  gland,  or  during  the  course  of  the  circulation,  there  is  no  certain 
means  of  ascertaining.  It  is  evident  that  this  secretion  cannot  serve  as  the 
channel  for  the  deportation  of  any  element  the  accumulation  of  which  would  be 
injurious  to  the  system ;  since  it  does  not  occur  in  the  male  at  all,  and  is  pre- 
sent in  the  female  at  particular  times  only.  Yet  there  is  reason  to  belieye  that 
if,  whilst  the  process  is  going  on,  it  be  suddenly  checked,  the  retention  of  the 
material  in  the  blood,  or  the  reabsorption  of  the  secreted  fluid,  is  attended  with 
injurious  consequences.  Thus  if,  when  the  milk  is  first  secreted,  the  child  be 
not  put  to  the  breast,  an  accumulation  takes  place,  which,  if  not  relieved,  occa- 
sions great  general  disturbance  of  the  system.  The  narrowness  of  the  orifices  of 
the  milk-tubes  obstructs  the  spontaneous  exit  of  the  fluid,  especially  in  primi- 
paras;  the  reservoirs  and  ducts  become  loaded;  further  secretion  is  prevented; 
and  a  state  of  congestion  of  the  vessels  of  the  gland,  tending  to  inflammation,  is 
induced.  The  accompanying  fever  is  partly  due,  no  doubt,  to  the  local  disturb- 
ance ;  but  in  part,  also,  there  seems  reason  to  believe,  to  the  reabsorption  of 
the  milk  into  the  blood ;  this  cannot  but  be  injurious,  since,  although  but 
little  altered,  the  constitution  of  milk  is  essentially  different,  especially  in 
regard  to  the  quantity  of  crystallizable  matter  (sugar)  which  it  contains. — The 
instances  of  the  vicarious  secretion  of  milk  are  not  numerous ;  and  in  no  instance 
is  there  an^proof  that  the  elements  of  the  fluid  were  pre-existent  in  the  blood. 
Some  of  the  most  curious  are  those  in  which  it  has  been  poured  out  from  a  gland 
in  the  groin ;  but  it  is  probable  that  this  was  in  consequence  of  the  existence 
of  a  real  repetition,  in  that  place,  of  the  true  mammary  structure ;  this  being 
the  situation  of  the  mammae  of  many  of  the  inferior  animals,  of  which  the 
hoinologues  in  Man  are  usually  undeveloped.1 

1  The  following  is  a  more  unequivocal  case  of  vicarious  secretion ;  and  it  is  peculiarly 
interesting  as  exhibiting  the  injmious  effects  of  the  reabsorption  of  the  secretion,  and  the 
relief  which  the  system  experienced  when  it  was  separated  from  the  blood  by  the  new 
channel.  "  A  lady  of  delicate  constitution  (with  a  predisposition  to  pneumonia)  was  pre- 
vented from  suckling  her  child,  as  she  desired,  by  the  following  circumstance :  Soon  after 
her  delivery  she  had  a  severe  fever,  during  which  her  breasts  became  very  large,  and 
hard ;  the  nipples  were  swollen  and  firm ;  and  there  was  evidently  an  abundant  secretion 
of  milk ;  but  neither  the  sucking  of  the  infant,  nor  any  artificial  means,  could  draw  a  sin- 
gle drop  of  fluid  from  the  swollen  glands.  It  was  clear  that  the  milk-tubes  were  closed ; 
and  as  the  breasts  continued  to  grow  larger  and  more  painful,  purgatives  and  other  means 
were  employed  to  check  the  secretion  of  milk.  After  three  days  the  fever  somewhat 
diminished,  and  was  replaced  by  a  constant  cough,  which  was  at  first  dry,'  but  soon  after 
was  followed  by  the  expectoration  of  simple  mucus.  After  this,  the  cough  diminished 
in  severity,  and  the  expectoration  became  easy;  but  the  sputa  were  no  longer  mucous, 
but  were  composed  of  a  liquid,  which  had  all  the  physical  characters  of  genuine 
milk.  This  continued  for  fifteen  days ;  the  quantity  of  milk  expectorated  amounting  to 


1028  OP   GENERATION. 

1030.  Of  the  quantity  of  Milk  ordinarily  secreted  by  a  good  Nurse,  it  is 
difficult  to  form  a  correct  estimate  j1  since  the  amount  which  can  be  artificially 
drawn  affords  no  criterion  of  that  which  is  secreted  at  the  time  of  the  "draught" 
(§  948).  The  quantity  which  can  be  squeezed  from  either  breast  at  any  one 
time,  and  which,  therefore,  must  have  been  contained  in  its  tubes  and  reservoirs, 
is  about  two  ounces.  The  amount  secreted  is  greatly  influenced  by  the  mental 
and  physical  condition  of  the  female,  and  also  by  the  quantity  and  character  of 
the  ingesta.  In  regard  to  the  influence  of  the  mental  state  upon  this  secretion, 
ample  details  have  already  been  given  (CHAP.  xvin.).  With  respect  to  the 
physical  state  most  favorable  to  the  production  of  an  ample  supply  of  this  im- 
portant fluid,  it  may  be  stated  generally  that  sound  health,  a  vigorous  but 
not  plethoric  constitution,  regular  habits,  moderate  but  not  fatiguing  exercise, 
and  an  adequate  but  not  excessive  amount  of  nutritious  food,  furnish  the 
conditions  most  required.  It  is  seldom  that  stimulating  liquors,  which  are 
so  commonly  indulged  in,  are  anything  but  prejudicial ;  but  the  unmeasured 
condemnation  of  them  in  which  some  writers  have  indulged  is  certainly  inju- 
dicious; as  experience  amply  demonstrates  the  improvement  in  the  condi- 
tion both  of  mother  and  infant,  which  occasionally  results  from  the  moderate 
employment  of  them.  Their  modus  operandi,  when  they  are  really  beneficial, 
seems  to  lie  in  promoting  the  digestive  process,  and  in  thus  aiding  in  the  ap- 
propriation of  those  nutritive  materials  which  constitute  the  real  source  of  the 
solid  constituents  of  the  milk. — The  influence  of  various  Medicines  upon  the 
Milk  is  another  important  question  which  has  not  yet  been  sufficiently  investi- 
gated. As  a  general  rule,  it  appears  that  the  most  soluble  saline  compounds 
pass  into  the  milk  as  into  other  secretions ;  but  there  are  many  exceptions. 
Common  salt,  the  sesquicarbonate  of  soda,  sulphate  of  soda,  iodide  of  potassium, 
oxide  of  zinc,  trisnitrate  of  bismuth,  and  sesquioxide  of  iron,  have  been  readily 
detected  in  the  milk,  when  these  substances  were  experimentally  administered 
to  an  Ass;  and  ordinary  experience  shows  that  the  Human  infant  is  affected 
by  many  of  these,  when  they  are  administered  to  the  mother.  The  influence  of 
mercurial  medicines  taken  by  the  mother  in  removing  from  the  infant  a  syphi- 
litic taint  possessed  by  both,  is  also  well  known.  The  vegetable  purgatives, 
especially  castor-oil,  senna,  and  colocynth,  have  little  effect  upon  the  milk ; 
hence  they  are  to  be  preferred  to  the  saline  aperients,  when  it  is  not  desired  to 
act  upon  the  bowels  of  the  child. 

three  ounces  or  more  in  tlie  twenty- four  hours.  The  breasts  gradually  diminished  in  size: 
and  by  the  time  that  the  expectoration  ceased,  they  had  regained  their  natural  dimensions. 
The  same  complete  obstacle  to  the  flow  of  milk  from  the  nipples  recurred  after  the  births 
of  four  children  successively  with  the  same  sequelae.  After  the  sixth,  she  had  the  same 
symptoms  of  fever,  but  this  time  they  were  not  followed  by  bronchitis  or  the  expectoration 
of  milk ;  she  had  in  their  stead  copious  sweatings,  which,  with  other  severe  symptoms, 
reduced  her  to  a  cachectic  state,  and  terminated  fatally  in  a  fortnight."  ("  Bulletino  delle 
Scienze  Mediche,"  Apr.  1839;  and  "Brit,  and  For.  Med.  Review,"  Jan.  1840.) 

1  For  an  estimate  by  M.  Guillot,  founded  on  the  comparative  weight  of  the  Infant 
before  and  after  lactation,  see  "  L' Union  Medicale,"  1852,  No.  16.  The  total  amount  con- 
sidered by  Mons.  G.  to  be  usually  drawn  in  the  twenty-four  hours,  varies  from  32  oz.  to 
64  oz.  ( Apoth. ) ;  but  his  estimates  are  vitiated  by  the  extraordinary  frequency  of  the 
lactations  observed,  the  infant  being  put  to  the  breast  from  25  to  30  times  in  the  twenty- 
four  hours. 


GENERAL   CONSIDERATIONS,  1029 


CHAPTER  XX. 

OF    THE   DIFFERENT    BRANCHES   OF   THE    HUMAN    FAMILY, 
AND    THEIR   MUTUAL   RELATIONS. 

1. —  General  Considerations. 

1031.  AMONGST  the  various  tribes  of  Men  which  people  the  surface  of  the 
globe,  and  which  are  separated  from  all  other  animals  by  the  characters  for- 
merly described  (CHAP.  I.),  there  are  differences  of  a  very  striking  and  important 
nature.     They  are  distinguishable  from  each  other,  not  merely  by  their  lan- 
guage, dress,  manners  and  customs,  religious  belief,  and  other  acquired  pecu- 
liarities, but  in  the  physical  conformation  of  their  bodies  j  and  the  difference 
lies,  not  merely  in  the  color  of  the  skin,  the  nature  of  the  hair,  the  form  of  the 
soft  parts  (such  as  the  nose,  lips,  &c.),  but  in  the  shape  of  the  skull,  and  of 
other  parts  of  the  bony  skeleton,  which  might  be  supposed  to  be  less  liable  to 
variation.     It  is  a  question  of  great  scientific  interest,  as  well  as  one  that  con- 
siderably affects  the  mode  in  which  we  regard  the  races  that  differ  from  our  own, 
whether  they  are  all  of  one  species,  that  is,  descended  from  the  same  or  from 
similar  parentage — or  whether  they  are  to  be  considered  as  distinct  species,  the 
first  parents  of  the  several  races  having  had  the  same  differences  among  them- 
selves as  those  which  are  now  exhibited  by  their  descendants. 

1032.  In  order  to  arrive  at  a  just  conclusion  on  this  subject,  it  is  necessary 
to  take  a  very  extensive  survey  of  the  evidence  furnished  by  a  number  of  differ- 
ent lines  of  inquiry.     Thus,  in  the  first  place,  it  is  right  to  investigate  what  are 
the  discriminating  structural  marks  by  which  species  are  distinguished  among 
other  tribes  of  animals. — Secondly,  it  should  be  ascertained  to  what  extent 
variation  may  proceed  among  races  which  are  historically  known  to  have  a  com- 
mon parentage,  and  what  are  the  circumstances  which  most  favor  such  variations. 
— Thirdly,  the  extreme  variations  which  present  themselves  among  the  different 
races  of  Men  should  be  compared  with  those  which  occur  among  tribes  of  ani- 
mals known  to  be  of  the  same  parentage;  and  it  should  be  questioned,  at  the  same 
time,  whether  the  circumstances  which  favor  the  production  of  varieties  in  the 
latter  case  are  in  operation  in  the  former. — Fourthly,  where  it  is  impossible  to 
trace  back  distinct  races  to  their  origin,  it  is  to  be  inquired  how  far  agreement  in 
physiological  and  psychological  peculiarities  may  be  regarded  as  indicating  spe- 
cific identity,  even  where  a  considerable  difference  exists  in  bodily  conformation ; 
and  this  test,  if  it  can  be  determined  on,  has  to  be  applied  to  Man. — Fifthly,  it 
must  be  attempted,  by  a  detailed  examination  of  the  varieties  of  the  Human  race 
themselves,  to  ascertain  whether  their  differences  in  conformation  are  constant ;  or 
whether  there  are  not  occasional  manifestations,  in  each  race,  of  a  tendency  to 
assume  the  characters  of  others ;  so  as  to  prevent  any  definite  lines  being  drawn 
between  the  several  tribes,  which  together  make  up  the  (supposed)  distinct 
species. — An  investigation  so  comprehensive  could  not  be  followed  out,  even  in 
the  most  cursory  manner  that  would  be  consistent  with  utility,  within  the  limits 
of  the  present  work ;  and  no  more  will  be  attempted,  therefore,  than  an  indica- 
tion of  the  principal  points  of  difference  among  the  several  Races  of  Men,  and  a 


1030      OF    THE    HUMAN    FAMILY,    AND   THEIR    MUTUAL   RELATIONS. 

statement  of  the  results   of  inquiry  into   their  degree   of  constancy  in  each 
group  which  they  can  be  used  to  separate.1 

1033.  The  differential  characters  on  which  those  have  relied  who  have  sought 
to  establish  the  existence  of  a  plurality  of  species  among  Mankind,  are  both 
Anatomico-Physiological,  and  Psychological.     Under  the  former  head  rank  the 
Color  of  the  Skin,  the  texture  of  the  Hair,  and  the  conformation  of  the  bony 
Skeleton,  especially  the   Skull.     The  latter  consist  in  the  superiority  claimed 
for  some  races  over  others  in  intellectual  power,  and  in  moral  and  religious 
capacity.     The  former  group  will  be  the  one  first  considered. 

1034.  The  Color  of  the  skin  exists  in  the  Epidermis  only ;  and  it  depends 
upon  the  admixture  of  pigment-cells  with  the  ordinary  epidermic  cells  (§  242)  ] 
all  the  varied  hues  presented  by  the  different  races  of  men  being  due  to  the 
relative  amount  of  these  cells,  and  to  the  particular  tint  of  the  pigment  which 
they  form.     It  would  be  easy,  by  selecting  well-marked  specimens  of  each  race, 
to  make  it  appear  that  color  affords  a  character  sufficiently  distinctive  for  their 
separation ;  thus,  for  example,  the  fair  and  ruddy  Saxon,  the  jet-black  Negro, 
the  olive   Mongolian,  and  the  copper-colored  North  American,  might  be  con- 
sidered to  be  positively  separated  from  each  other  by  this  character — propagated 
as  it  seems  to  be,  with  little  or  no  perceptible  change,  from  generation  to  gene- 
ration.    But,  although  such  might  appear  to  be  the  clear  and  obvious  result  of 
a  comparison  of  this  kind,  yet  a  more  profound  and  comprehensive  survey  tends 
to  break  down  the  barrier  that  would  be  thus  established.     For,  on  tracing  this 
character  through  the  entire  family  of  Man,  we  find  the  isolated  specimens,  just 
noticed,  to  be  connected  by  such  a  series  of  links,  and  the  transition  from  one 
to  the  other  to  be  so  very  gradual,  that  it  is  impossible  to  say  where  the  line  is 
to  be  drawn.     There  is  nothing  here,  then,  which  at  all  approaches  to  those 
fixed  and  definite  marks  that  are  always  held  to  be  requisite  for  the  establish- 
ment of  specific  distinctions  among  other  tribes  of  animals. 

1035.  But,  further,  there  is  abundant  evidence  that  these  distinctions  are  far 
from  being  constantly  maintained,  even  in  any  one  race.     For  among  all  the 
principal  subdivisions,  albinoism,  or  the  absence  of  pigment-cells,  occasionally 
presents  itself ;  so  that  the  fair  skin  of  the  European  may  present  itself  in  the 
offspring  of  the  Negro  or  of  the  Red  Man.3     On  the  other  hand,  instances  are 
by  no  means  rare,  of  the  unusual  development  of  pigment-cells  in  individuals 

1  The  whole  of  this  investigation  has  been  most  elaborately,  and  in  the  Author's  opin- 
ion most  successfully,  worked  out  by  Dr.  Prichard  in  his  profound  and   philosophical 
Treatise  on  the  "  Physical  History  of  Man."     For  a  more  concise  view  of  Dr.  Prichard' s 
argument,  with  some  additional  considerations  not  embraced  in  it,  the  Author  may  refer 
to  his  own  article  on  the  "Varieties  of  the  Human  Species,"  in  the  "  Cyclop,  of  Anat. 
and  Phys.,"  vol.  iv. 

2  A  very  curious  example  of  change  of  color  in  a  Negro  has  been  recently  recorded,  on 
unquestionable  authority. — The  subject  of  it  is  a  negro  slave  in  Kentucky,  aet.  45,  who 
was  born  of  black  parents,  and  was,  himself,  perfectly  black  until  12  years  of  age.     At 
that  time  a  portion  of  the  skin,  an  inch  wide,  encircling  the  cranium  just  within  the  edge 
of  the  hair,  gradually  changed  to  white  ;  also  the  hair  occupying  that  locality.     A  white 
spot  next  appeared  near  the  inner  canthus  of  the  left  eye  ;  and  from  this  the  white  color 
gradually  extended   over   the  face,  trunk,  and  extremities,  until  it   covered   the   entire 
surface.     The  complete  change  from  black  to  white  occupied  about  ten  years  ;  and,  but 
for  his  hair,  which  was  crisped  or  woolly,  no  one  would  have  supposed  at  this  time  that 
his  progenitors  had  offered  any  of  the  characteristics  of  the  Negro,  his  skin  presenting 
the  healthy  vascular  appearance  of  that  of  a  fair-complexioned  European.     When  he  was 
about  22  years  of  age,'  however,  dark  copper-colored,  or  brown  spots  began  to  appear  on 
the  face  and  hands ;  but  these  have  remained  limited  to  the  portions  of  the  surface  ex- 
posed to  light. — About  the  time  that  the  black  color  of  his  skin  began  to  disappear,  he 
completely  lost  his  sense  of  smell ;  and  since  he  has  become  white,  he  has  had  measles 
and  hooping-cough  a  second  time.     (See  Dr.  Hutchison's  account  of  this  case  in  the 
"Amer.  Journ.  of  Med.  ScL,"  Jan.  1852.) 


GENERAL    CONSIDERATIONS.  1031 

of  the  fair-skinned  races  ;  so  that  parts  of  the  body  are  of  a  dark  red,  or  brown 
hue,  or  are  even  quite  black.  Such  modifications  may  seem  of  little  importance  to 
the  argument ;  since  they  are  confined  to  individuals,  and  may  be  put  aside  as 
accidental.  But  there  is  ample  evidence  that  analogous  changes  may  take  place 
in  the  course  of  time,  which  tend  to  produce  a  great  variety  of  shades  of  color, 
in  the  descendants  of  any  one  stock.  Thus,  in  the  great  Indo-European  family 
(part  of  the  Caucasian  race  of  Blumenbach),  which  may  be  unquestionably 
regarded  as  having  had  a  common  origin,  we  find  races  with  fair  complexion, 
yellow  hair,  and  blue  eyes — others  presenting  the  xanthous  or  olive  hue— -and 
others  decidedly  black.  A  similar  diversity  may  be  seen  among  the  American 
races,  which  are  equally  referable  to  one  common  stock  ;  and  it  exists  to  nearly 
the  same  extent  among  the  African  nations,  which  are  similarly  related  to  each 
other.  It  may  be  freely  admitted,  that  among  European  colonists  settled  in 
hot  climates,  such  changes  do  not  present  themselves  within  a  few  generations ; 
but  in  many  well-known  instances  of  earlier  colonization,  they  are  very  clearly 
manifested.  Thus,  the  wide  dispersion  of  the  Jewish  nation,  and  their  remarka- 
ble isolation  (maintained  by  their  religious  observances)  from  the  people  among 
whom  they  live,  render  them  peculiarly  appropriate  subjects  for  such  observa- 
tions ;  and  we  accordingly  find  that  the  brunette  complexion  and  dark  hair, 
which  are  usually  regarded  as  characteristic  of  that  race,  are  frequently  super- 
seded, in  the  Jews  of  Northern  Europe,  by  red  or  brown  hair,  and  fair  com- 
plexion ;  whilst  the  Jews  who  settled  in  India  some  centuries  ago,  have  become 
as  dark  as  the  Hindoos  around  them. 

1036.  The  relation  of  the  complexions  of  the  different  races  of  Men  to  the 
climates  they  respectively  inhabit,  is  clearly  established  by  an  extended  com- 
parative survey  of  both.     From  such  a  survey  the  conclusion  is  inevitable,  that 
the  intertropical  region  of  the  earth  is  the  principal  seat  of  the  darkest  races  of 
Men;  whilst  the  region  remote  from  the  tropics  is  that  of  the  fairer  races;  and 
that  the  climates  approaching  the  tropics  are  generally  inhabited  by  nations 
which  are  of  an  intermediate  complexion.     To  this  observation,  it  may  be  added 
that  high  mountains,  and  countries  of  great  elevation,  are  generally  inhabited 
by  people  of  a  lighter  color  than  are  those  of  which  the  level  is  low,  such  as 
swampy  or  sandy  plains  upon  the  sea-coast.     These  distinctions  are  particularly 
well  seen  in  Africa,  where  the  tropics  almost  exactly  mark  out  the  limits  of 
the  black  complexion  of  the  inhabitants ;  and  where  the  deepest  hue  is  to  be 
seen  among  the  Negroes  of  the  G-uinea  Coast,  whose  residence  unites  both  the 
conditions  just  mentioned;  whilst  the  mountainous  regions  in  their  immediate 
vicinity  are  inhabited  by  tribes  of  a  much  lighter  aspect. 

1037.  The  nature  of  the  Hair  is,  perhaps,  one  of  the  most  permanent  charac- 
teristics of  different  races.     In  regard  to  its  color,  the  same  statements  apply 
as  those  just  made  with  respect  to  the  color  of  the  skin;  the  variety  of  hue 
being  given  by  pigment-cells,  which  may  be  more  or  less  developed  under  dif- 
ferent circumstances.     But  it  has  been  thought  that  its  texture  afforded  a  more 
valid  ground  of  distinction ;  and  it  is  commonly  said,  that  the  substance  which 
grows  on  the  head  of  the  African  races,  and  of  some  other  dark-colored  tribes 
(chiefly  inhabiting  tropical  climates),  is  wool,  and  not  hair.     This,  however,  is 
altogether  a  mistake;  for  microscopic  examination  clearly  demonstrates  that 
the  hair  of  the  Negro1  has  exactly  the  same  structure  with  that  of  the  European ; 
and  that  it  does  not  bear  any  resemblance  to  wool,  save  in  its  crispness  and 

1  It  is  a  very  common  mistake,  especially  in  the  United  States,  to  consider  Negro  as 
synonymous  with  African.  So  far  is  this  from  being  the  fact,  that,  as  Dr.  Latham  justly 
remarks,  "the  true  Negro  area,  the  area  occupied  by  men  of  the  black  skin,  thick  lips, 
and  woolly  hair,  is  exceedingly  small ;  as  small  in  proportion  to  the  rest  of  the  continent, 
as  the  area  of  the  district  of  the  stunted  Hyperboreans  is  in  Asia,  or  that  of  the  Lapps  in 
Europe."  ("  Natural  History  of  the  Varieties  of  Man,"  p.  471.) 


1032      OP   THE    HUMAN   FAMILY,    AND    THEIR   MUTUAL   RELATIONS. 

tendency  to  curl.  Moreover,  even  this  character  is  far  from  being  a  constant 
one;  for,  whilst  Europeans  are  not  unfrequently  to  be  met  with,  whose  hair  is 
nearly  as  crisp  as  that  of  the  Negro,  there  is  a  great  variety  amongst  the  Negro 
races  themselves,  which  present  every  gradation  from  a  completely  crisp  (or 
what  is  termed  woolly)  hair,  to  merely  curled  or  even  flowing  locks.  A  similar 
observation  holds  good  in  regard  to  the  natives  of  the  islands  of  the  great 
Southern  Ocean,  where  some  individuals  possess  crisp  hair,  whilst  others,  of  the 
same  race,  have  it  merely  curled.  It  is  evident,  then,  that  no  characters  can 
be  drawn  from  the  color  or  texture  of  the  hair  in  Man,  sufficiently  fixed  and 
definite  to  serve  for  the  distinction  of  races;  and  this  view  is  borne  out  by  the 
evident  influence  of  climate,  in  producing  changes  in  the  hairy  covering  of 
almost  every  race  of  domestic  animals;  such  changes  often  manifesting  them- 
selves in  the  very  individuals  that  have  been  transported  from  one  country  to 
another,  and  yet  more  distinctly  in  succeeding  generations. 

1038.  It  has  been  supposed  that  varieties  in  the  configuration  of  the  Skele- 
ton would  afford  characters  for  the  separation  of  the  Human  races,  more  fixed 
and  definite  than  those  derived  from  differences  in  the  form,  color,  or  texture  of 
the  soft  parts  which  clothe  it.     And  attention  has  been  particularly  directed  to 
the  skull  and  the  pelvis,  as  affording  such  characters.     It  has  been  generally 
laid  down  as  a  fundamental  principle,  that  all  those  nations  which  are  found  to 
resemble  each  other  in  the  shape  of  their  heads  must  needs  be  more  nearly  re- 
lated to  each  other  than  they  are  to  tribes  of  Men  which  differ  from  them  in 
this  particular.     But  if  this  principle  be  rigorously  carried  out,  it  will  tend  to 
bring  together  races  which  inhabit  parts  of  the  globe  very  remote  from  each 
other,  and  which  have  no  other  mark  of  affinity  whatever ;  whilst,  on  the  other 
hand,  it  will  often  tend  to  separate  races  which  every  other  character  would 
lead  us  to  bring  together.     It  is  to  be  remembered,  moreover,  that  the  varieties 
in  the  conformation  of  the  skeleton,  presented  by  the  breeds  of  domesticated 
animals,  are  at  least  equal  to  those  which  are  manifested  in  the  conformation 
and  color  of  their  soft  parts;  and  we  might  reasonably  expect,  therefore,  to 
meet  with  similar  variations  among  the  Human  races.    It  is  probable,  however, 
that  climate  has  not  so  much  influence  in  producing  such  changes  in  the  con- 
figuration of  the  body,  as  is  exerted  by  the  peculiar  habits  and  mode  of  life  of 
the  different  races;  and  Dr.  Prichard  has  pointed  out  a  very  remarkable  rela- 
tion of  this  kind,  in  regard  to  the  three  principal  types  of  form  presented  by 
the  Skull. 

1039.  Among  the  rudest  tribes  of  Men,  hunters  and  savage  inhabitants  of 
forests,  dependent  for  their  supply  of  food  on  the  accidental  produce  of  the  soil 
or  on  the  chase — among  whom  are  the  most  degraded  of  the  African  nations, 
and  the  Australian  savages — a  form  of  head  is  prevalent,  which  is  most  aptly 
distinguished  by  the  term  prognathous,  indicating  a  prolongation  or  forward-ex- 
tension of  the  jaws  (Fig.  284).     This  character  is  most  strongly  marked  in  the 
Negroes  of  the  Gold  Coast,  whose  skulls  are  usually  so  formed  as  to  give  the 
idea  of  lateral  compression.     The  temporal  muscles  have  a  great  extent,  rising 
high  on  the  parietal  bones;  the  cheek-bones  project  forward,  and  not  outward; 
the  upper  jaw  is  lengthened  and  projects  forwards,  giving  a  similar  projection 
to  the  alveolar  ridge  and  to  the  teeth  ;  and  the  lower  jaw  has  somewhat  of  the 
same  oblique  projection,  so  that  the  upper  and  lower  incisor  teeth  are  set  at  an 
obtuse  angle  to  each  other,  instead  of  being  nearly  in  parallel  planes,  as  in  the 
European.     From  the  shape  of  the  upper  jaw  alone,  would  result  a  marked 
diminution  in  the  facial  angle,  measured  according  to  the  method  of  Camper; 
but  this  diminution  is  far  from  being  sufficient  to  approximate  the  Ethiopian 
races  to  the  higher  Apes,  as  some  have  supposed  it  to  be  (§  8).     Independently 
of  the  diminution  of  the  facial  angle,  resulting  from  the  projection  of  the  upper 
jaw,  it  is  quite  certain  that,  in  the  typical  prognathous  skull,  there  is  a  want  of 


GENERAL   CONSIDERATIONS. 


1033 


elevation  of  the  forehead ;  but  it  does  not  appear  that  there  is  a  corresponding 
diminution  in  the  capacity  of  the  cranial  cavity,  the  retreating  form  of  the  fore- 
Fig.  284. 


Profile  and  basal  views  of  the  Prognathous  Skull  of  a  Negro. 

head  being  partly  due  to  the  general  elongation  of  the  skull  in  the  antero-poste- 
rior  direction.  Nor  is  it  true,  as  stated  by  some,  that  the  position  of  the  fora- 
men magnum  in  the  Negro  is  decidedly  behind  that  which  it  holds  in  the 
European,  in  this  respect  approaching  that  of  the  Apes  (§  2) :  since,  if  due 
allowance  be  made  for  the  projection  of  the  upper  jaw,  this  aperture  is  found  to 
have  the  same  position  in  the  prognathous  skull  as  in  the  oval  one,  namely, 
exactly  behind  the  transverse  line  bisecting  the  antero-posterior  diameter  of  the 
base  of  the  cranium.  The  prognathous  skull  is  further  remarkable  for  the 
large  development  of  the  parts  connected  with  the  organs  of  sense,  especially 
those  of  smell  and  hearing.  The  aperture  of  the  nostrils  is  very  wide;  and  the 
internal  space  allowed  for  the  expansion  of  the  Schneiderian  membrane,  and  for 
the  distribution  of  the  olfactory  nerve,  is  much  larger  than  in  most  European 
heads.  The  posterior  openings  of  the  nasal  cavity  are  not  less  remarkable  for 
their  width,  than  the  anterior.  The  external  auditory  meatus  is  also  peculiarly 
wide  and  spacious;  and  the  orbital  cavities  have  been  thought  to  be  of  more 
than  ordinary  capacity — but  this  last  is  by  no  means  a  constant  character. 

1040.  A  second  type  of  cranial  conformation,  very  different  from  the  pre- 
ceding, belongs  principally  to  the  Nomadic  races,  who  wander  with  their  herds 
and  flocks  over  vast  plains ;  and  to  the  tribes  who  creep  along  the  shores  of  the 
Icy  Sea,  and  live  partly  by  fishing,  and  in  part  on  the  flesh  of  their  reindeer. 
This  form,  designated  by  Dr.  Prichard  as  the  pyramidal  (Fig.  285),  is  typically 
exhibited  by  various  nations  of  Northern  and  Central  Asia;  and  is  seen,  in  an 
exaggerated  degree,  in  the  Esquimaux.  Its  most  striking  character  is  the  lateral 
or  outward  projection  of  the  zygoma,  which  is  due  to  the  form  of  the  malar  bones. 
These  do  not  project  forwards  and  downwards  under  the  eyes,  as  in  the  progna- 
thous skull;  but  take  a  direction  laterally  or  outwards,  forming,  with  the  zygo- 
matic  process  of  the  temporal  bone,  a  large  rounded  sweep  or  segment  of  a 
circle.  From  this,  in  connection  with  the  narrowness  of  the  forehead,  it  results, 
that  lines  drawn  from  the  zygomatic  arches,  touching  the  temples  on  either 
side,  instead  of  being  parallel  (as  in  Europeans)  meet  over  the  forehead,  so  as  to 
form  with  the  basis  a  triangular  figure.  The  upper  part  of  the  face  being  re- 
markably flat,  the  nose  also  being  flat,  and  the  nasal  bones,  as  well  as  the  space 
between  the  eyebrows,  being  nearly  on  the  same  plane  with  the  cheek-bones, 


1034      OF   THE    HUMAN    FAMILY,    AND    THEIR    MUTUAL   RELATIONS 


the  triangular  space  bounded  by  these  lines  may  be  compared  to  one  of  the 
faces  of  a  pyramid.     The  orbits  are  large  and  deep;  and  the  peculiar  conforma- 

Fig.  285. 


Fig.  286. 


Front  and  basal  views  of  the  Pyramidal  Skull  of  an  Esquimaux. 

tion  of  the  bones  which  surround  it,  gives  to  the  aperture  of  the  lids  an  ap- 
pearance of  obliquity — the  inner  angle  seeming  to  be  directed  downwards.  The 
whole  face,  instead  of  presenting  an  oval  form,  as  in  most  Europeans  and  Afri- 
cans, is  of  a  lozenge-shape.  The  greater  relative  development  of  the  zygomatic 
bones,  and  of  the  bones  of  the  face  altogether,  when  compared  with  the  capacity 
of  the  cranium,  indicates  in  the  pyramidal  skull  a  more  ample  extension  of  the 
organs  subservient  to  sensation ;  the  same  effect  being  thus  produced  by  lateral 
expansion,  as  by  the  forward  extension  of  the  facial  bones  in  the  prognathous 
skulls. 

1041.  The  most  civilized  races — those  which  live  by  agriculture  and  the 
arts  of  cultivated  life — all  the  most  intellectually  improved  nations  of  Europe 
and  Asia — have  a  shape  of  the  head  which  differs  from  both  the  preceding 
forms,  and  which  may  be  termed  oval  or  elliptical  (Fig.  286).  This  at  once  ap- 
proves itself  as  a  more  symmetrical  form ;  no  part  having  an  excessive  promi- 
nence ;  whilst,  on  the  other  hand,  there 
is  nowhere  an  appearance  of  undue 
flattening  or  compression.  The  head 
is  altogether  of  a  rounder  shape  than  in 
other  varieties,  and  the  forehead  is 
more  expanded;  while  the  maxillary 
bones  and  the  zygomatic  arches  are  so 
formed  as  to  give  the  face  an  oval 
shape,  nearly  on  a  plane  with  the  fore- 
head and  cheek-bones,  and  not  project- 
ing towards  the  lower  part.  Owing  to 
the  more  perpendicular  direction  of  the 
alveolar  processes,  the  front  teeth  are 
fixed  in  planes  which  are  nearly  or 
quite  parallel  to  each  other.  The 
principal  features  in  this  form  of  cra- 
nium are  thus  of  a  negative  character; 
Oval  Skull  of  an  European.  the  chief  positive  distinction  is  the  large 

development  of  the  cranial  cavity,  and 
especially  the  fulness  and  elevation  of  the  forehead,  in  proportion  to  the  size  of 


GENERAL   CONSIDERATIONS.  1035 

the  face ; — indicating  the  predominance  of  the  intellectual  powers  over  those 
merely  instinctive  propensities  which  are  more  directly  connected  with  sensa- 
tions. Among  European  nations,  the  Greeks  have  probably  displayed  the 
greatest  symmetry  and  perfection  in  the  form  of  the  head;  but  various  departures 
may  be  traced  towards  the  preceding  forms,  when  we  compare  the  crania  of 
different  races,  and  even  of  individuals,  belonging  to  the  same  stock — some 
approaching  the  pyramidal  form  of  the  Northern  Asiatics,  whilst  others  approxi- 
mate to  the  prognathous  type  of  the  Negro. 

1042.  The  influence  of  habits  of  life,  continued  from  generation  to  generation, 
upon  the  form  of  the  head,  is  remarkably  evinced  by  the  transition  from  one 
type  to  another,  which  may  be  observed  in  nations  that  have  undergone  a  change 
in  their  manners  and  customs,  and  have  made  an  advance  in  civilization.  Thus, 
to  mention  but  one  instance,  the  Turks  at  present  inhabiting  the  Ottoman  and 
Persian  empires  are  undoubtedly  descended  from  the  same  stock  with  the 
nomadic  races  which  are  still  spread  through  Central  Asia  (§  1053).  The 
former,  however,  having  conquered  the  countries  which  they  now  inhabit,  eight 
centuries  since,  have  gradually  settled  down  to  the  fixed  and  regular  habits  of 
the  Indo-European  race,  and  have  made  corresponding  advances  in  civilization ; 
whilst  the  latter  have  continued  their  wandering  mode  of  life,  and  can  scarcely 
be  said  to  have  made  any  decided  advance  during  the  same  interval.  Now  the 
long  since  civilized  Turks  have  undergone  a  complete  transformation  into  the  like- 
ness of  Europeans ;  whilst  their  nomadic  relatives  retain  the  pyramidal  configu- 
ration of  the  skull  in  a  very  marked  degree.  Some  have  attributed  this  change 
in  the  physical  structure  of  the  Turkish  race  to  the  introduction  of  Circassian 
slaves  into  the  harems  of  the  Turks ;  but  this  could  only  affect  the  opulent  and 
powerful  amongst  the  race ;  and  the  great  mass  of  the  Turkish  population  have 
always  intermarried  among  themselves.  The  difference  of  religion  and  manners 
must  have  kept  them  separate  from  those  Greeks  whom  they  subdued  in  the  new 
Ottoman  countries;  and  in  Persia,  the  Tajiks,  or  real  Persians,  still  remain 
quite  distinct  from  their  Turkish  rulers,  belonging  to  a  different  sect  among  the 
Mussulmans,  and  commonly  living  apart  from  them. — In  like  manner,  even  the 
Negro  head  and  face  may  become  assimilated  to  the  European,  by  long  sub- 
jection to  similar  influences;  thus,  in  some  of  our  older  West  Indian  Colonies, 
it  is  not  uncommon  to  meet  with  Negroes,  the  descendants  of  those  first  intro- 
duced there,  who  exhibit  a  very  European  physiognomy ;  and  it  has  even  been 
asserted  that  a  Negro  belonging  to  the  Dutch  portion  of  Guiana  may  be  distin- 
guished from  another  belonging  to  the  British  settlements,  by  the  similarity  of 
the  features  and  expression  of  each,  to  those  which  peculiarly  characterize  his 
masters.  The  effect  could  not  be  here  produced  by  the  intermixture  of  bloods, 
since  this  would  be  made  apparent  by  alteration  of  color. — But  not  only  may 
the  pyramidal  and  prognathous  types  be  elevated  towards  the  elliptical ;  the 
elliptical  may  be  degraded  towards  either  of  these.  Want,  squalor,  and  igno- 
rance have  a  special  tendency  to  induce  that  diminution  of  the  cranial  portion 
of  the  skull,  and  that  increase  of  the  facial,  which  characterize  the  prognathous 
type  ;  as  cannot  but  be  observed  by  any  one  who  takes  an  accurate  and  candid 
survey  of  the  condition  of  the  most  degraded  part  of  the  population  of  the  great 
towns  of  this  country,  but  as  is  seen  to  be  pre-eminently  the  case  with  regard  to 
the  lowest  classes  of  Irish  immigrants.1  A  certain  degree  of  retrogression  to 
the  pyramidal  type  is  also  to  be  noticed  among  the  nomadic  tribes  which  are 
to  be  found  in  every  civilized  community.  Among  these,  as  has  been  remarked 
by  a  very  acute  observer,3  "According  as  they  partake  more  or  less  of  the  purely 
vagabond  nature,  doing  nothing  whatsoever  for  their  living,  but  moving  from 

1  See  the  "  Dublin  University  Magazine,"  No.  xlviii. 

2  Mr.  Henry  May  hew,  in  "  London  Labor  and  the  London  Poor,"  p.  2. 


1036      OF   THE   HUMAN    FAMILY,   AND   THEIR   MUTUAL  RELATIONS. 

place  to  place,  preying  on  the  earnings  of  the  more  industrious  portion  of  the 
community,  so  will  the  attributes  of  the  nomade  races  be  found  more  or  less 
marked  in  them ;  and  they  are  all  more  or  less  distinguished  for  their  high 
cheek-bones  and  protruding  jaws/ '  thus  showing  that  kind  of  mixture  of  the 
pyramidal  with  the  prognathous  type  which  is  to  be  seen  among  the  lowest  of 
the  Indian  and  Malayo-Polynesian  races. 

1043.  Next  to  the  characters  derived  from  the  form  of  the  head,  those  which 
are  founded  upon  the  form  of  the  pelvis  seem  entitled  to  rank.     These  have 
been  particularly  examined  by  Professors  Vrolik  and  Weber.     The  former  was 
led,  by  his  examinations  of  this  part  of  the  skeleton,  to  consider  that  the  pelvis 
of  the  Negress,  and  still  more  that  of  the  female  Hottentot,  approximates  to 
that  of  the  Simiae  in  its  general  configuration ;  especially  in  its  length  and 
narrowness — the  iliac  bones  having  a  more  vertical  position,  so  that  the  anterior 
spines  approach  one  another  much  more  closely  than  they  do  in  the  European ; 
and  the  sacrum  also  being  longer  and  narrower.     On "  the  other  hand,  Prof. 
Weber1  concludes,  from  a  more  comprehensive  survey,  that  no  particular  figure 
is  a  permanent  characteristic  of  any  one  race.     Pie  groups  the  principal  varieties 
which  he  has  met  with,  according  to  the  form  of  the  upper  opening — whether 
oval,  round,  four-sided,  or  wedge-shaped.     The  first  of  these  is  most  frequent  in 
the  European  races ;  the  second,  among  the  American  races ;  the  third,  most 
common  among  the  Mongolian  nations,  corresponds  remarkably  with  the  form 
of  their  heads  ;  whilst  the  last  chiefly  occurs  among  the  races  of  Africa,  and  is 
in  like  manner  conformable  with  the  oblong  compressed  form  usually  presented 
by  their  cranium.     But  though   there  are  particular  shapes  which  are  most 
prevalent  in  each  race,  yet  there  are  numerous  individual  deviations,  of  such  a 
nature  that  every  variety  of  form  presents  itself  occasionally  in  any  given  race. 

1044.  Other  variations  have  been  observed  by  anatomists,  in  the  relative 
length  of  the  bones,  and  in  the  shape  of  the  limbs,  between  the  different  races 
of  Man  j  but  these  also  seem  to  have  reference  to  the  degree  of  civilization,  and 
to  the  regularity  of  the  supply  of  wholesome  nutriment.     It  is  generally  to  be 
observed  that  the  races  least  improved  by  civilization,  like  the  uncultivated 
breeds  of  animals,  have  slender,  lean,  and  elongated  limbs;  this  may  be  especially 
remarked  in  the  natives  of  Australia.     In  nearly  all  the  less  civilized  races  of 
Men,  the  limbs  are  more  crooked  and  badly  formed  than  the  average  of  those 
of  Europeans ;  and  this  is  particularly  the  case  in  the  Negro,  the  bones  of  whose 
legs  bow  outwards,  and  whose  feet  are  remarkably  flat.     It  has  been  generally 
believed  that  the  length  of  the  forearm  in  the  Negro  is  so  much  greater  than 
in  the  European,  as  to  constitute  a  real  character  of  approximation  to  the  Apes. 
The  difference,  however,  is  in  reality  extremely  slight;  and  is  not  at  all  compara- 
ble with  that  which  exists  between  the  most  uncultivated  races  of  Men  and  the 
highest  Apes  (§  5).     And  in  regard  to  all  the  peculiarities  here  alluded  to,  it 
is  to  be  observed  that  they  can  only  be  discovered  by  the  comparison  of  large 
numbers  of  one  race  with  corresponding  numbers  of  another ;  for  individuals 
are  found  in  every  tribe  possessing  the  characters  which  distinguish  the  major- 
ity of  the  other  race.     Such  peculiarities,  therefore,  are  totally  useless  as  the 
foundation  of  specific  characters;  being  simply  variations  from  the  ordinary 
type,  resulting  from  causes  which  might  affect  the  entire  race,  as  well  as  indi- 
viduals.— The  connection-  between  the  general  form  of  the  body,  on  the  one 
hand,  and  the  degree  of  civilization  (involving  the  regular  supply  of  nutriment) 
on  the  other,  is  made  apparent,  not  merely  by  the  improvement  which  we 
perceive  in  the  form,  development,  and  vigor  of  the  frame,  as  we   advance 
from  the  lowest  to  the  most  cultivated  of  the  Human  races;  but  also  by  the 

1  "  Die  Lehre  von  den  Ur-  und  Racenformen  der  Schaedel  und  Becken  des  Menschen  ;" 
Dusseldorf,  1830. 


GENERAL   CONSIDERATIONS.  1037 

degradation  that  is  occasionally  to  be  met  with  in  particular  groups  of  the  higher 
tribes  which  have  been  subjected  for  several  generations  to  the  influence  of 
depressing  causes.  Of  such  degradation,  occurring  under  circumstances  that 
permit  its  successive  steps  to  be  traced,  we  have  a  remarkable  example  in  the 
conversion  of  certain  tribes  of  the  Hottentot  race  into  Bushmen  (§  1058)  ;  and 
there  is  very  strong  ground  for  the  belief  that  similar  influences  have  operated, 
at  a  more  remote  period,  in  the  production  of  the  peculiar  characters  of  the 
Guinea  Coast  Negroes  and  Australian  Bushmen. 

1045.  Independently,  however,  of  the  obvious  modifying  influence  of  external 
circumstances,  much  allowance  must  be  made  for  that  tendency  to  variation, 
which  presents  itself,  more  or  less,  in  all  those  races  of  animals  which  possess 
such  a  constitutional  capability  of  adaptation  to  changes  in  climate,  habits  of 
life,  &c.,  as  enables  them  to  live  and  flourish  under  a  variety  of  conditions. 
Thus  we  find  that  the  offspring  of  any  one  pair  of  domesticated  animals  do  not 
all  precisely  agree  among  themselves,  or  with  their  parents,  either  in  bodily 
conformation  or  in  psychical  character;  but  that  individual  differences,  as  they 
are  termed,  exist  among  them.  Now,  as  this  tendency  to  variation  cannot  be 
clearly  traced  to  any  influence  of  external  circumstances,  it  is  commonly  dis- 
tinguished by  the  term  "  spontaneous ;"  but  there  is  no  effect  without  a  cause ; 
and  as  the  widest  differences  of  this  kind  present  themselves  in  those  races  which 
are  most  obviously  amenable  to  the  influence  of  external  conditions,  we  seem 
justified  in  attributing  them  to  agencies  operating  unostensibly  upon  the  parents, 
either  previously  to  their  intercourse,  or  at  the  time  of  coition  (§  975),  or  in 
the  female  during  the  period  of  utero-gestation  (§  1014).  The  difference 
between  wild  and  domesticated  animals  in  regard  to  color  affords  a  very  good 
illustration  of  this  general  fact ;  for  the  uniformity  among  the  former  is  no  less 
remarkable  than  the  want  of  constancy  among  the  latter ;  and  whilst  variety  of 
color  soon  gives  place  to  uniformity,  when  domesticated  races  return  in  any 
considerable  degree  towards  their  primitive  state,1  it  very  speedily  develops 
itself  in  races  which  are  undergoing  the  converse  process.3 — Now  it  is  by  taking 
advantage  of  those  "spontaneous"  departures  from  the  ordinary  type  which 
present  features  of  value  to  the  breeders  of  domesticated  animals,  that  new  races 
are  developed  from  time  to  time  among  these;  any  strongly  marked  peculiarity 
which  thus  appears  in  only  a  single  individual  being  usually  transmitted  to  some 
of  its  offspring,  and  being  almost  certainly  perpetuated  when  both  parents  are  dis- 
tinguished by  it,  as  happens  when  the  products  of  the  first  procreation  become 
capable  of  breeding  with  each  other.3 — Now  there  can  be  no  hesitation  in  ad- 
mitting that  the  tendency  to  the  so-called  u  spontaneous"  variation  prevails  in 
the  Human  race  to  a  greater  degree  than  in  any  other ;  since  we  find  most 
remarkable  diversities  in  features,  complexion,  hair,  and  general  conformation, 

1  This  has  been  especially  noticed  in  the  horses,  cattle,  sheep,  hogs,  and  dogs,  introduced 
by  the  Spaniards  into  South  America. 

2  Thus  Mr.   T.  Bell  informs  us  ("British  Quadrupeds,"  2d  edit.  p.  203)  that  an 
Australian  bitch,  or  dingo,  in  the  Zoological  Gardens,  had  a  litter  of  puppies,  the  father 
of  which  was  also  of  that  breed ;  both  parents  had  been  taken  in  the  wild  state ;  both  were 
of  the  uniform  reddish-brown  color  which  belongs  to  the  race,  and  the  mother  had  never 
bred  before  ;  but  the  young,  bred  in  confinement,  and  in  a  half  domesticated  state,  were 
all  more  or  less  spotted. 

3  See  the  history  of  the  introduction  of  the  ancon  breed  of  sheep,  characterized  by  a 
peculiar  conformation  of  its  limbs,  in  Massachusetts,  given  by  Col.  Hutchinsonin  the  "  Phil. 
Trans."  for  1813.     A  very  similar  account  has  been  i-ecently  given  by  Prof.  Owen  (in  a 
Lecture  delivered  before  the  Society  of  Arts,  Dec.  10,  1851),  respecting  the  recent  introduc- 
tion of  a  new  breed  of  merino  sheep,  distinguished  for  the  long,  smooth,  straight,  and  silky 
character  of  the  wool,  and  now  known  as  the  Mauchamp  breed. — In  both  instances,  the 
breed  originated  in  the  spontaneous  appearance  of  a  male  lamb  possessing  the  peculiarities 
in  question ;  and  from  its  offspring  such  a  selection  was  made  by  the  breeder  as  enabled 
him  to  bring  together  males  and  females  both  of  which  were  distinguished  by  them. 


1038      OF   THE    HUMAN    FAMILY,   AND    THEIR    MUTUAL   RELATIONS. 

among  the  offspring  of  the  same  parentage ;  whilst  more  special  modifications  of 
the  ordinary  type,  such  as  the  possession  of  six  fingers  on  each  hand  and  of  six 
toes  on  each  foot,  are  of  no  unfrequent  occurrence.  Under  ordinary  circum- 
stances, these  modifications  tend  to  disappear  as  often  as  they  occur;  the  free 
intermixture  of  those  members  of  the  race  which  possess  them,  with  those  which 
depart  less  from  the  ordinary  type,  tending  to  merge  them  in  the  general 
average.  But  there  can  be  no  reasonable  doubt  that,  if  the  same  kind  of 
segregation  were  practised  among  mankind  which  is  adopted  by  the  breeders 
of  animals  for  the  purpose  of  perpetuating  a  particular  variety — if,  for  example, 
the  members  of  a  six-fingered  family  were  to  intermarry  exclusively  with  one 
another — any  such  variety  would  be  permanently  established  as  a  new  race. 
Now  if  it  be  borne  in  mind,  that  the  influence  of  a  scanty  population,  in  the 
early  ages  of  the  human  race,  by  isolating  different  families  from  each  other, 
and  causing  intermarriages  among  even  the  nearest  relatives,  would  have  been 
precisely  the  same  with  that  which  is  now  exercised  by  the  breeders  of  animals, 
we  see  one  reason  why  the  varieties  which  then  arose  should  have  a  much  greater 
tendency  to  self-perpetuation  than  those  which  now  occasionally  present  them- 
selves. And  when,  too,  it  is  borne  in  mind,  that  the  change  in  external  condi- 
tions induced  by  migration  would  thus  operate  not  only  upon  the  parents,  but 
upon  the  offspring,  and  would  have  a  continual  influence  in  so  modifying  the 
constitution  of  the  latter  that  the  peculiarities  thus  acquired  by  them  would  be 
transmitted  in  yet  greater  intensity  to  their  progeny,  there  is  no  real  difficulty 
in  accounting,  upon  the  strictest  physiological  principles,  for  the  widest  depar- 
tures from  one  common  type  of  conformation  which  we  encounter  in  our  survey 
of  the  different  Races  of  Mankind.1 

1046.  Hence  we  are  led  to  conclude,  that,  so  far  as  regards  their  Anatomical 
structure,  there  is  no  such  difference  among  them  as  would  justify  to  the  Zoolo- 
gist the  assertion  of  their  distinct  origin.     But,  further,  it  can  be  shown  that, 
although  the  comparison  of  the  structural  characters  of  the  Human  races  does 
not  furnish  any  positive  evidence  of  their  descent  from  a  common  stock,  it 
proves  that  even  if  their  stocks  were  originally  distinct,  there  could  have  been 
no  essential  difference  between  them ;  the  descendants  of  any  one  such  stock 
being  able  to  assume  the  characters  of  another.     This,  as  already  remarked,  can 
be  proved  by  historical  evidence  in  regard  to  a  sufficient  number  of  tribes,  to 
justify  the  same  assertion  with  respect  to  others,  whose  languages,  customs, 
habits  of  thought,  &c.,  have  an  affinity  strong  enough  to  warrant  us  in  regard- 
ing them  as  descendants  of  the  same  stock,  whilst  their  physical  conformation 
is  widely  different.     Each  principal  geographical  area,  that  is  so  isolated  from 
others  as  to  render  it  probable,  a  priori,  that  its  population  has  extended  from 
one  centre — such  as  the  Continent  of  Africa  or  America — contains  races  of  very 
diversified  physical  characters,  whose  linguistic  affinities  make  it  almost  certain 
that  they  must  have  had  a  common  descent ;  and  thus,  in  whatever  mode  the 
types  of  the  principal  varieties  are  selected,  they  are  found  to  be  connected  by 
so  gradual  a  series  of  intermediate  or  transitional  forms,  that  it  is  impossible  to 
draw  any  such  line  of  demarcation  between  them,  as  would  be  required  by  a 
soundly-judging  Naturalist  for  the  boundary  of  distinct  species. 

1047.  A  very  important  confirmation  of  this  view  is  afforded  by  the  essential 
agreement  which  exists  among  the  different  Races  of  Men  in  regard  to  their 
Physiological  history;  the  variations  which  they  present  not  being  greater  than 

1  For  a  masterly  digest  of  the  analogical  evidence  furnished  by  the  changes  known  to 
have  been  thus  produced  among  domesticated  animals,  and  of  the  modifications  which 
particular  tribes  of  Men  can  be  shown  to  have  undergone  within  the  historic  period,  see 
Dr.  Prichard's  "Physical  History  of  Mankind,"  and  his  "Natural  History  of  Man;'' 
see,  also,  the  summary  given  by  the  Author  in  the  "  Cyclop,  of  Anat.  and  Physiol.,"  vol. 
iv.  pp.  1301-1339. 


GENERAL   CONSIDERATIONS.  1039 

those  which  we  meet  with  between  the  different  individuals  of  any  one  race. 
Thus,  we  not  only  find  the  average  duration  of  life  to  be  the  same  (making 
allowance  for  circumstances  which  are  likely  to  induce  disease),  but  the  various 
epochs  of  life — such  as  the  times  of  the  first  and  second  dentition,  the  period 
of  puberty,  the  duration  of  pregnancy,  the  intervals  of  the  catamenia,  and  the 
time  of  their  final  cessation — present  a  marked  general  uniformity,  such  as  does 
not  exist  among  similar  epochs  in  the  lives  of  species  that  are  nearly  allied,  but 
yet  unquestionably  distinct.  Further,  the  different  races  of  Man  are  all  subject 
to  the  same  diseases,  both  sporadic,  endemic,  and  epidemic;  the  only  exceptions 
being  those  in  which  the  constitution  of  a  race  has  grown-to  a  certain  set  of 
influences  (as  that  of  the  Negro  to  the  malaria  which  produces  certain  pernicious 
fevers  in  the  European),  producing  an  hereditary  immunity  in  the  race,  which 
is  capable  of  being  acquired  by  individuals  of  other  races,  by  a  process  of  accli- 
matization commenced  sufficiently  early.1 — The  most  important  physiological 
test,  however,  of  specific  unity  or  diversity  is  that  furnished  by  the  Generative 
process.  It  may  be  considered  as  a  fundamental  fact,  alike  in  the  Vegetable 
and  in  the  Animal  kingdom,  that  hybrid  races,  originating  in  the  sexual  con- 
nection of  individuals  of  two  different  species,  do  not  tend  to  self-perpetuation; 
the  hybrids  being  nearly  sterile  with  each  other,  although  they  may  propagate 
with  either  of  their  parent  races,  in  which  the  hybrid  race  will  soon  merge ; 
whilst,  on  the  other  hand,  if  the  parents  be  themselves  varieties  of  the  same 
species,  the  hybrid  constitutes  but  another  variety,  and  its  powers  of  repro- 
duction are  rather  increased  than  diminished,  so  that  it  may  continue  to  pro- 
pagate its  own  race,  or  may  be  used  for  the  production  of  other  varieties,  almost 
ad  infinitum.  It  appears  that,  among  Plants,  hybrids  originating  between 
undoubtedly  distinct  species,  sometimes  reproduce  themselves  for  two  or  three 
generations,  but  do  not  continue  beyond  the  fourth.  Amongst  Animals.,  the 
limits  of  hybridity  between  parents  of  distinct  species  are  more  narrow,  since 
the  hybrid  is  totally  unable  to  continue  its  race  with  one  of  its  own  kind;3  and 
although  it  may  propagate  with  one  of  its  parent-species,  the  progeny  will  of 
course  approach  in  character  to  the  pure  breed,  and  the  race  will  speedily 
merge  into  it.  In  Animals,  as  among  Plants,  the  mixed  offsprings,  originating 
from  different  races  within  the  limits  of  the  same  species,  generally  exceed  in 
vigor,  and  in  the  tendency  to  multiply,  the  parent-races  from  which  they  are 
produced,  so  as  to  gain  ground  upon  the  older  varieties,  and  gradually  to  super- 
sede them.  In  this  manner,  by  the  crossing  of  the  breeds  of  our  domesticated 
animals,  many  new  and  superior  varieties  have  been  produced.  The  general 
principle  is,  then,  that  beings  of  distinct  speciesj  or  descendants  from  stocks 

1  This  view  of  the  immunity  of  the  Negro  race  from  certain  forms  of  Fever  which  are 
very  fatal  to  Europeans,  is  justified,  the  Author  believes,  by  all  the  facts  known  upon  the 
subject.     Much  may  be  set  down,  as  he  is  assured  by  Dr.  Daniell,  to  the  better  adaptation 
of  the  Negro  habits  of  life  to  their  climate  ;  and  Europeans  who  exercise  due  caution 
(especially  in  regard  to  the  functions  of  the  skin)  may  preserve  an  immunity  scarcely  less 
complete.     Dr.  D.  himself,  having  been  taken  prisoner  by  one  of  the  Negro  tribes  at  an 
early  age,  and  having  spent  two  years  among  them,  seems  to  have  been  thoroughly  accli- 
matized ;   and  has  subsequently  passed  many  years  on  the  most  unhealthy  parts  of  the 
coast,  without  experiencing  any  severe  attacks  of  illness,  and  in  the  enjoyment  of  very 
good  general  health.     It  is  sometimes  maintained  that  the  Negro  race  possesses  such  a 
complete  exemption  from  the  Yellow  Fever  of  the  United  States,  as  marks  its  specific 
difference ;   such,  however,  is  not  constantly  the  case,  since  Negroes  occasionally  suffer 
from  it;  and  their  comparative  immunity  seems  fairly  attributable  to  the  constitutional 
peculiarity  acquired  by  their  African  progenitors,  and  capable  of  being  acquired  by  Euro- 
peans also. 

2  One  or  two  instances  have    been  stated  to  occur,  in  which  a  Mule  has  produced 
offspring  from  union  with  a  similar  animal ;   but  this  is  certainly  the  extreme  limit,  since 
no  one  has  ever  maintained  that  the  race  can  be  continued  further  than  the  second  gene- 
ration, without  admixture  with  one  of  the  parent-species. 


1040      OF   THE   HUMAN   PAMILY,    AND   THEIR   MUTUAL    RELATIONS. 

originally  different,  cannot  produce  a  mixed  race  which  shall  possess  the  capa- 
bility of  perpetuating  itself;  whilst  the  union  of  varieties  has  a  tendency  to 
produce  a  race  superior  in  energy  and  fertility  to  its  parents. — The  application 
of  this  principle  to  the  Human  races  leaves  no  doubt  with  respect  to  their 
specific  unity ;  for,  as  is  well  known,  not  only  do  all  the  races  of  Men  breed 
freely  with  each  other ;  but  the  mixed  race  is  generally  superior  in  physical 
development,  and  in  tendency  to  rapid  multiplication,  to  either  of  the  parent 
stocks ;  so  that  there  is  much  reason  to  believe  that,  in  many  countries,  the 
mixed  race  between  the  Aborigines  and  European  colonizers  will  ultimately 
become  the  dominant  power  in  the  community.  This  is  especially  the  case  in 
India,  South  America,  and  Polynesia. 

1048.  The  question  of  Psychical  conformity  or  difference  among  the  Races 
of  Mankind  is  one  which  has  a  most  direct  bearing  upon  the  question  of  their 
specific  unity  or  diversity ;  but  it  has  an  importance  of  its  own,  even  greater 
than  that  which  it  derives  from  this  source.  For,  as  has  been  recently  argued 
with  great  justice  and  power,1  the  real  Unity  of  Mankind  does  not  lie  in  the 
consanguinity  of  a  common  descent,  but  has  its  basis  in  the  participation  of 
every  race  in  the  same  moral  nature,  and  in  the  community  of  moral  rights 
which  hence  becomes  the  privilege  of  all.  "This  is  a  bond  which  every  man 
feels  more  and  more,  the  farther  he  advances  in  his  intellectual  and  moral  cul- 
ture, and  which  in  this  development  is  continually  placed  upon  higher  and 
higher  ground ;  so  much  so,  that  the  physical  relation  arising  from  a  common 
descent  is  finally  lost  sight  of,  in  the  consciousness  of  the  higher  moral  obliga- 
tions." It  is  in  these  obligations  that  the  moral  rights  of  men  have  their 
foundation;  and  thus,  "while  Africans  have  the  hearts  and  consciences  of  human 
beings,  it  could  never  be  right  to  treat  them  as  domestic  cattle  or  as  wild-fowl, 
if  it  were  ever  so  abundantly  demonstrated  that  their  race  was  but  an  improved 
species  of  ape,  and  ours  a  degenerate  kind  of  god." — The  Psychical  comparison 
of  the  various  Races  of  Mankind  is  really,  therefore,  in  a  practical  point  of  view, 
the  most  important  part  of  the  whole  investigation ;  but  it  has  been,  neverthe- 
less, the  one  most  imperfectly  pursued,  until  the  inquiry  was  taken  up  by  Dr. 
Prichard.  The  mass  of  evidence  which  he  has  accumulated  on  this  subject, 
however,  leaves  no  reasonable  doubt  that  no  more  "  impassable  barrier"  really 
exists  between  the  different  races  with  respect  to  this,  than  in  regard  to  any  of 
those  points  of  ostensible  diversity  which  have  been  already  considered ;  the 
variations  in  the  positive  and  relative  development  of  their  respective  psychical 
powers  and  tendencies,  not  being  greater,  either  in  kind  or  degree,  than  those 
which  present  themselves  between  individuals  of  our  own  or  of  any  other  race, 
by  some  members  of  which  a  high  intellectual  and  moral  standard  has  been 
attained.  The  tests  by  which  we  recognize  the  claims  of  the  outcast  and  de- 
graded of  our  own  or  of  any  other  "  highly-civilized"  community,  to  a  common 
humanity,  are  the  same  as  those  by  which  we  should  estimate  the  true  relation 
of  the  Negro,  the  Bushman,  or  the  Australian,  to  the  cultivated  European.  If, 
on  the  one  hand,  we  admit  the  influence  of  want,  ignorance,  and  neglect,  in 
accounting  for  the  debasement  of  the  savages  of  our  own  great  cities — and 
if  we  witness  the  same  effects  occurring  under  the  same  conditions  among  the 
Bushmen  of  Southern  Africa  (§  1058) — we  can  scarcely  hesitate  in  admitting 
that  the  long-continued  operation  of  the  same  agencies  has  had  much  to  do  with 
the  psychical  as  well  as  the  physical  deterioration  of  the  Negro,  Australian, 
and  other  degraded  savages.  So,  on  the  other  hand,  if  we  cherish  the  hope 
that  the  former,  so  far  from  being  irreclaimable,  may  at  least  be  brought  up  to 
the  standard  from  which  they  have  degenerated,  by  means  adapted  to  develop 

1  See  the  "New  Quarterly  Preview,"  No.  xv.,  p.  131  ;  and  an  Article  by  Prof.  Agassiz 
in  the  "Christian  Examiner,"  Boston  (N.  E.),  1850. 


GENERAL   CONSIDERATIONS.  1041 

their  intellectual  faculties  and  to  call  forth  the  higher  parts  of  their  moral 
nature,  no  adequate  reason  can  be  assigned  why  the  same  method  should  not 
succeed  with  the  latter,  if  employed  with  sufficient  perseverance.  It  will  be 
only  when  the  effect  of  education,  intellectual,  moral,  and  religious,  shall  have 
been  fairly  tested  by  the  experience  of  many  generations,  in  conjunction  with 
the  influence  of  a  perfect  equality  in  civilization  and  social  position,  that  we 
shall  be  entitled  to  speak  of  any  essential  and  constant  psychical  difference  be- 
tween ourselves  and  the  most  degraded  beings  clothed  in  a  human  form.  All 
the  evidence  which  we  at  present  possess  leads  to  the  belief  that,  under  a  vast 
diversity  in  degree  and  in  modes  of  manifestation,  the  same  intellectual,  moral, 
and  religious  capabilities  exist  in  all  the  Eaces  of  Mankind ;  so  that,  whilst  we 
may  derive  from  this  conformity  a  powerful  argument  for  their  zoological  Unity 
as  a  species,  we  are  also  directly  led  to  recognize  their  community  of  moral 
nature  with  ourselves,  and  to  admit  them  to  a  participation  in  our  own  rights. 

1049.  Most  important  assistance  is  afforded  in  the  determination  of  the  real 
affinities  of  different  Races,  by  the  study  of  their  Languages.  This,  however, 
is  a  department  of  the  inquiry  so  far  beyond  the  limits  of  Physiological  science, 
that  it  must  be  here  dismissed  with  a  bare  mention  of  the  results,  to  which  the 
zealous  pursuit  of  it  by  a  large  number  of  philosophic  philologists  seems  un- 
doubtedly to  tend. — There  can  be  no  reasonable  doubt  that,  as  a  general  princi- 
ple, the  affinities  of  races  are  more  surely  indicated  by  their  languages,  than  by 
their  physical  features ;  and  the  experienced  philologist  is  generally  able  to  dis- 
criminate those  resemblances  which  may  have  arisen  out  of  the  introduction  of 
words  or  of  modes  of  construction  from  the  one  into  the  other,  by  conquest, 
commercial  intercourse,  or  absolute  intermixture,  from  those  which  are  the  re- 
sult of  a  community  of  origin.  And  thus  are  supplied  those  means  of  tracing 
the  past  history  of  races,  which  are  seldom  afforded  by  historical  records,  or 
even  (at  least  with  any  degree  of  certainty)  by  traditional  information.  It  is  to 
be  borne  in  mind,  that  the  affinities  of  languages  are  indicated,  not  merely  by 
verbal  resemblance,  but  by  the  similarity  of  their  modes  of  grammatical  con- 
struction, or  the  methods  by  which  the  relation  between  different  words  that 
constitute  sentences  is  indicated.  The  most  positive  evidence  is  of  course 
afforded,  when  a  conformity  exists  both  in  the  vocabularies  and  in  the  types  of 
construction  of  two  languages ;  but  it  frequently  happens  that  although  the  con- 
formity exists  in  regard  to  one  of  these  alone,  yet  the  evidence  which  it  affords 
is  perfectly  satisfactory.  Thus,  there  are  many  cases  in  which  these  vocabularies 
are  so  continually  undergoing  important  changes  (the  want  of  written  records 
not  permitting  them  to  acquire  more  than  a  traditional  permanence),  that  their 
divergence  becomes  so  great,  even  in  the  course  of  a  few  generations,  as  to  pre- 
vent tribes  which  are  by  no  means  remotely  descended  from  a  common  ancestry, 
from  understanding  one  another;  whilst  yet  the  system  of  grammatical  con- 
struction, which  depends  more  upon  the  grade  of  mental  development  and  upon 
habits  of  thought,  exhibits  a  remarkable  permanence.  Such  appears  to  be  true 
of  the  whole  group  of  American  languages,  which  seem,  as  a  whole,  to  be  legi- 
timately referable  to  a  common  stock,  notwithstanding  their  complete  verbal 
diversity.  On  the  other  hand,  when  two  languages  or  groups  of  languages 
differ  greatly  in  construction,  but  present  that  kind  of  verbal  correspondence  on 
which  the  philologist  feels  justified  in  placing  most  reliance  (namely,  an  essen- 
tial conformity  in  those  "primary  words/'  which  serve  to  represent  the  universal 
ideas  of  a  people  in  the  most  simple  state  of  existence),  that  correspondence  may 
be  held  to  indicate  a  community  of  origin,  if  it  can  be  proved  that  it  has  not 
been  the  result  of  intercourse  between  the  two  families  of  nations  subsequently 
to  their  first  divergence,  and  if  it  seems  probable  on  other  grounds  that  their 
separation  took  place  at  a  period  when  as  yet  the  grammatical  development  of 
both  languages  was  in  its  infancy.  Such  appears  to  have  been  the  case  with 
66 


1042      OF   THE   HUMAN   FAMILY,   AND   THEIR   MUTUAL  RELATIONS. 

certain  of  those  groups  of  languages  whose  distinctness  can  be  traced  back  his- 
torically for  the  longest  period. — It  is  evident,  then,  that  philological  inquiry 
must  be  looked  to  as  one  of  the  chief  means  of  determining  the  question  of 
radiation  from  a  single  centre  or  from  multiple  centres ;  and  it  is  a  remarkable 
fact,  that  the  linguistic  affinity  and  the  conformity  in  physical  characters  fre- 
quently stand  in  a  sort  of  complemental  relation  to  each  other,  each  being  the 
strongest  where  the  other  is  weakest ;  so  that  by  one  or  other  of  these  links  of 
connection,  a  close  relationship  is  indicated  between  all  these  families  of  nations, 
under  which  the  several  races  appear  to  be  most  naturally  grouped. 

2. —  General  Survey  of  the  Principal  Families  of  Mankind. 

1050.  The  distribution  of  the  Races  of  Mankind  under  five  primary  varieties, 
according  to  their  respective  types  of  cranial  conformation,  as  first  proposed  by 
Blumenbach,  is  still  so  commonly  received,  notwithstanding  the  distinct  proof 
which  has  been  given  of  the  fallacious  nature  of  its  basis,  that  it  will  be  de- 
sirable to  explain  his  terms,  and  at  the  same  time  to  show  how  far  the  informa- 
tion subsequently  acquired  has  tended  to  modify  his  arrangement. — The  first  of 
these  varieties,  which  is  considered  to  be  distinguished  by  the  possession  of  the 
oval  or  elliptical  type  of  cranial  conformation,  was  designated  Caucasian  by 
Blumenbach,  on  two  grounds ;  first,  because  he  considered  the  Caucasian  people 
(Georgians  and  Circassians)  as  presenting  its  physical  characters  in  the  great- 
est perfection ;  and  second,  because  it  was  supposed  that  the  Caucasian  range  of 
mountains  might  be  regarded  as  the  centre  or  focus  of  the  races  belonging  to  it. 
Neither  of  these  ideas,  however,  is  correct :  for  whilst  the  oval  form  of  cranium 
is  presented  with  fully  as  great  beauty  and  symmetry  by  the  Greeks,  it  seems 
now  to  be  almost  certainly  determinable  by  the  evidence  of  language,  that  the 
Georgian  and  Circassian  nations  are  really  of  Mongolian  origin,  and  consequently 
have  no  direct  relation  of  affinity  with  the  other  nations  usually  ranked  as  belong- 
ing to  this  variety;  and  the  evidence  of  history  and  tradition,  so  far  from  pointing 
to  the  Caucasian  range  as  the  original  centre  of  radiation  of  the  race,  accords 
with  that  of  language  in  assigning  its  locality  much  nearer  to  Central  Asia.  It 
would  be  most  desirable,  therefore,  that  some  other  designation  should  be  sub- 
stituted for  that  given  by  Blumenbach;  were  it  not  that  the  present  state  of 
our  knowledge  requires  the  entire  abandonment  of  his  doctrine,  that  the  races 
agreeing  in  this  type  of  conformation  are  mutually  connected  by  community  of 
descent.  For,  even  within  the  limits  of  Europe,  we  find  at  least  two  nations — 
the  Turks,  and  the  Magyars  or  true  Hungarians — whose  crania  are  character- 
istically oval,  and  which  are  yet  undoubtedly  of  Mongolian  descent ;  and  al- 
though some  allowance  must  be  made,  in  regard  to  the  change  which  has  taken 
place  among  the  former,  for  the  influence  of  intermixture  with  other  races,  yet 
there  is  no  reason  to  believe  that  any  such  influence  has  operated  among  the 
Magyars,  whose  blood  seems  to  have  been  transmitted  with  remarkable  purity 
from  the  time  when  they  settled  in  Hungary  about  ten  centuries  since.  In  Asia, 
we  find  this  type  presented  not  merely  by  the  Indo-European  races,  but  also  by 
the  Syro- Arabian,  and  by  the  larger  proportion  of  the  inhabitants  of  Hindostan  ; 
yet  the  Syro- Arabian  races  are  more  nearly  related  to  the  African  stock  (§  1052), 
than  to  that  from  which  most  of  the  present  inhabitants  of  Europe  have  sprung ; 
and  there  is  good  reason  to  believe  that  the  great  mass,  if  not  the  whole,  of  the 
existing  inhabitants  of  India,  are  of  Mongolian  descent  (§  1054).  It  will  be 
necessary,  therefore,  to  consider  the  nations  which  present  the  so-called  Cau- 
casian type  of  cranial  conformation,  under  several  distinct  heads.  No  uniformity 
exists  among  them  in  regard  to  color ;  for  this  character  presents  every  inter- 
mediate gradation  between  the  fair  and  florid  hue,  with  light,  red,  or  auburn 
hair,  of  the  Northern  European,  to  the  jet-black  of  many  tribes  in  Northern 


PRINCIPAL   FAMILIES   OF   MANKIND.  1043 

Africa  and  the  Indian  Peninsula.  The  hair  is  generally  long  and  flexible,  with 
a  tendency  to  curl;  but  considerable  variety  presents  itself  with  regard  to  this 
particular.  The  conformation  of  the  features  approaches  more  or  less  closely  to 
that  which  we  are  accustomed  to  regard  as  the  type  of  beauty. 

1051.  The  first  place,  in  a  more  natural  distribution  of  the  Human  Races, 
must  undoubtedly  be  given  to  that  which  is  designated  by  Dr.  Prichard  as  the 
Arian,  and  which  is  often  termed  the  Indo-European;  including  the  collective 
body  of  European  nations,  with  the  Persians,  Affghans,  and  certain  other  na- 
tions of  the  south-western  portion  of  the  Asiatic  continent,  near  to  which  their 
original  focus  appears  to  have  been.  The  great  bond  of  connection  between 
these  nations  lies  in  their  languages ;  which,  in  spite  of  great  diversities,  present 
a  certain  community  of  character  that  is  recognized  by  every  philologist.  The 
family  which  is  most  dissimilar  to  the  rest  is  that  which  is  formed  by  the  Celtic 
nations ;  these  are  undoubtedly,  like  the  others,  of  eastern  origin,  as  was  first 
shown  by  Dr.  Prichard  j1  but  they  appear  to  have  detached  themselves  from  the 
common  stock  at  an  earlier  period  in  the  development  of  its  language ;  and 
both  in  their  physical  conformation  and  in  their  psychical  character,  the  typical 
Celt  contrasts  remarkably  with  the  Germanic  group  of  nations.  The  languages 
of  the  whole  Indo-Germanic  group  are  united  alike  by  community  in  many  of 
the  most  important  "  primary  words/'  and  by  general  similarity  in  grammatical 
construction ;  being  obviously  all  formed  upon  the  same  base  with  the  ancient 
Sanskrit,  if  not  upon  the  Sanskrit  itself.  The  existing  Lettish  or  Lithuanian 
dialect  presents  a  very  near  approach  to  that  type  j  and  the  Old  Prussian,  a 
dialect  spoken  as  late  as  the  sixteenth  century,  had  a  still  closer  alliance  to  the 
ancient  Zend  or  Median,  which  seems  to  have  been  a  very  early  derivation  from 
the  Sanskrit,  and  which  is  the  basis  of  the  language  now  spoken  in  Persia.  But 
there  is  evidence  that,  notwithstanding  the  mutual  affinities  of  the  Indo-Grer- 
manic languages,  every  one  of  them  has  been  modified  by  the  introduction  of 
extraneous  elements :  thus,  in  those  of  Western  Europe,  there  is  a  considerable 
admixture  of  Celtic  ;  whilst  in  others  there  are  traces  of  more  barbaric  tongues. 
In  fact,  there  can  be  little  doubt  that  Europe  had  an  indigenous  population 
before  the  immigration  of  the  Indo-Gerinan  or  even  of  the  Celtic  tribes ;  and  of 
this  population  it  seems  most  probable  that  the  Lapps  and  Finns  of  Scandinavia, 
and  the  Euskarians  (or  Basques)  of  the  Biscayan  provinces,  are  but  the  remnant. 
The  former  of  these  tribes,  which  is  undoubtedly  of  Mongolian  origin,  once 
extended  much  further  south  than  at  present ;  and  with  regard  to  the  latter, 
whose  nearest  linguistic  affinities  are  also  with  the  tongues  of  High  Asia,  there 
is  ample  historical  proof  that  they  had  formerly  a  very  extensive  distribution 
through  Southern  Europe.  It  would  not  seem  improbable,  then,  that  the 
advance  of  the  Indo-European  tribes  from  the  south-east  corner  into  central 
Europe,  separated  that  portion  of  the  aboriginal  (Mongolian)  population  which 
they  did  not  absorb  or  destroy,  into  two  great  divisions ;  of  which  one  was 
gradually  pressed  northward  and  eastward,  so  as  to  be  restricted  to  Finland  and 
Lapland ;  and  the  other  southward  and  westward,  so  as  to  be  confined  at  the 
earliest  historic  period  to  a  part  of  the '  peninsula  of  Spain  and  the  south  of 
France,  gradually  to  be  driven  before  the  successive  irruptions  of  the  Celts, 
Romans,  Arabians,  and  other  nations,  until  their  scanty  remnant  found  an  en- 
during refuge  in  the  fastnesses  of  the  Pyrenees.3 — The  Indo-Germanic  race  is 
unquestionably  that  which  has  exercised  the  greatest  influence  on  the  civiliza- 

'  "On  the  Eastern  Origin  of  the  Celtic  Nations,"  1831. 

2  This  view,  which  was  suggested  by  the  Author  in  the  "Brit,  and  For.  Med.  Rev.," 
Oct.,  1847,  without  the ,  knowledge  that  it  had  been  elsewhere  propounded,  has  been 
put  forthwith  considerable  confidence  by  Dr.  Latham  ("Varieties  of  Man,"  1850),  as 
having  originated  with  Arndt  and  been  adopted  by  Rask,  distinguished  Scandinavian 
ethnologists. 


1044      OF   THE    HUMAN    FAMILY,    AND    THEIR    MUTUAL   RELATIONS. 

tion  of  the  Old  World ;  and  it  seems  indubitably  destined  to  acquire  a  similar 
influence  in  those  newly-found  lands  which  have  been  discovered  by  its  enter- 
prise. With  scarcely  an  exception,  as  Dr.  Latham  has  justly  remarked,  the 
nations  belonging  to  it  present  an  encroaching  frontier  :  there  being  no  instance 
of  its  permanent  displacement  by  any  other  race,  save  in  the  case  of  the  Arab 
dominion  in  Spain,  which  has  long  since  ceased :  in  that  of  the  Turkish  domin- 
ion in  Turkey  and  Asia  Minor,  which  is  evidently  destined  to  expire  at  no 
distant  period,  being  upheld  for  merely  political  purposes  by  extraneous  influ- 
ence ;  and  in  that  of  the  Magyars  in  Hungary,  who  only  maintain  their  ground 
through  their  complete  assimilation  to  the  Indo-Germanic  character.  It  is  a 
remarkable  fact  that  in  most  cases  in  which  this  race  extends  itself  into  coun- 
tries previously  tenanted  by  people  of  an  entirely  different  type,  the  latter  pro- 
gressively decline  and  at  last  disappear  before  it,  provided  the  climate  be  such 
as  enables  it  to  maintain  a  vigorous  existence ;  this  is  pre-eminently  the  case  in 
North  and  South  America,  in  Australia,  in  New  Zealand,  and  in  many  of  the 
smaller  Polynesian  islands.  And  where  the  climate  is  less  favorable  to  the 
perpetuation  of  the  race  in  its  purity,  an  intermixture  with  the  native  blood 
frequently  gives  rise  to  a  mixed  race,  which  possesses  the  developed  intellect  of 
the  one,  and  the  climatic  adaptiveness  of  the  other,  and  which  appears  likely 
ultimately  to  take  the  place  of  both. 

1052.  The  Syro-Aralian  or  Semitic  nations,  agree  with  the  preceding  in 
general  physical  characters,  but  differ  entirely  in  the  structure  of  their  language, 
and  for  the  most  part  in  vocabulary  also,  though  recent  researches  seem  to  indi- 
cate that  certain  roots  of  the  Semitic  and  Indo-Germanic  languages  have  a  decided 
affinity.  It  seems  quite  certain,  however,  that  the  linguistic  affinities  of  the 
Semitic  nations  are  rather  with  the  African  than  with  the  Indo-European  races ; 
and  so  strong  is  the  link  of  connection  thus  established,  that  by  Dr.  Latham 
they  are  ranked  with  the  former  under  the  general  designation  Atlantidsef 
whilst  Mr.  Norris,  whose  authority  upon  all  such  subjects  is  deservedly  great, 
is  strongly  disposed  (as  he  has  himself  informed  the  Author)  to  consider  them 
an  essentially  African  people. — The  original  centre  of  this  race,  however,  is 
commonly  reputed  to  have  been  that  region  of  Asia  which  is  intermediate  be- 
tween the  countries  of  the  Indo-European  and  of  the  Egyptian  races ;  having 
as  its  centre  the  region  watered  by  the  great  rivers  of  Mesopotamia.  Several 
of  the  nations  originally  constituting  this  group  have  become  extinct,  or  nearly 
so  ;  and  the  Arabs,  which  originally  formed  but  one  subdivision  of  it,  have  now 
become  the  dominant  race,  not  only  throughout  the  ancient  domain  of  the  Syro- 
Arabian  nations,  but  also  in  Northern  Africa.  In  the  opinion  of  Baron  Larrey, 
who  had  ample  opportunities  for  observation,  the  skulls  of  the  Arabian  race 
furnish,  at  present,  the  most  complete  type  of  the  human  head ;  and  he  con- 
sidered the  remainder  of  the  physical  frame  as  equally  distinguished  by  its 
superiority  to  that  of  other  races  of  men.  The  different  tribes  of  Arabs  present 
very  great  diversities  of  color,  which  are  generally  found  to  coincide  with  varia- 
tions in  climate.  Thus  the  Shegya  Arabs,  and  others  living  on  the  low  countries 
bordering  on  the  Nile,  are  of  a  dark-brown  or  even  black  hue ;  but  even  when 
quite  jetty,  they  are  distinguished  from  the  Negro  races  by  the  brightness  of 
their  complexions,  by  the  length  and  straightness  of  their  hair,  and  by  the 
regularity  of  their  features.  The  same  may  be  said  of  the  wandering  Arabs  of 
Northern  Africa ;  but  the  influence  of  climate  and  circumstances  is  still  more 
strongly  marked  in  some  of  the  tribes  long  settled  in  that  region,  whose  descent 
may  be  traced  to  a  distinct  branch  of  the  Syro- Arabian  stock,  namely,  the 
Berber,  to  which  belong  the  Kabyles  of  Algiers  and  Tunis,  the  Tuaryks  of 
Sahara,  and  the  Guanches  or  ancient  population  of  the  Canary  Isles.  Amongst 

'  See  his  "Varieties  of  Man,"  1850,  p.  469. 


PRINCIPAL   FAMILIES    OF   MANKIND.  1045 

these  tribes,  whose  affinity  is  indisputably  traceable  through  their  very  remark- 
able language,  every  gradation  may  be  seen,  from  the  intense  blackness  of  the 
'Negro  skin,  to  the  more  swarthy  hue  of  the  inhabitants  of  the  South  of  Europe. 
It  is  remarkable  that  some  of  the  Tuaryk  inhabitants  of  particular  Oases  in  the 
great  desert,  who  are  almost  as  insulated  from  communication  with  other  races 
as  are  the  inhabitants  of  islands  in  a  wide  ocean,  have  hair  and  features  that 
approach  those  of  the  Negroes ;  although  they  speak  the  Berber  language  with 
such  purity,  as  to  forbid  the  idea  of  the  introduction  of  these  characters  by  an 
intermixture  of  races.  The  Jews,  who  are  the  only  remnants  now  existing  of 
the  once  powerful  Phoenician  tribe,  and  who  are  now  dispersed  through  nearly 
every  country  on  the  face  of  the  earth,  present  a  similar  diversity ;  having 
gradually  assimilated  in  physical  characters  to  the  nations  among  which  they 
have  so  long  resided  (§  1035). 

1053.  The  second  primary  division  of  the  Human  family,  according  to  the 
arrangement  of  Blumenbach,  is  that  commonly  termed  Mongolian.  The  real 
Mongols,  however,  constitute  but  a  single  and  not  very  considerable  member  of 
the  group  of  nations  associated  under  this  designation ;  which  is,  therefore,  by 
no  means  an  appropriate  one.  The  original  seat  of  these  races  appears  to  have 
been  the  great  central  elevated  plain  of  Asia,  in  which  all  the  great  rivers  of 
that  continent  have  their  sources,  whatever  may  be  their  subsequent  direction* 
Taken  as  a  whole,  this  division  is  characterized  by  the  pyramidal  form  of  the 
skull,  whose  antero-posterior  diameter  scarcely  exceeds  the  parietal,  and  by  the 
broad  flat  face  and  prominent  cheek-bones;  by  the  flattening  of  the  nose,  which 
is  neither  arched  nor  aquiline ;  by  the  eyes  being  drawn  upwards  at  their  outer 
angle ;  by  the  xanthous  or  olive  complexion,  which  sometimes  becomes  fair,  but 
frequently  swarthy ;  by  the  scantiness  and  straightness  of  the  hair,  and  by 
deficiency  of  beard ;  and  by  lowness  of  stature.  These  characters,  however, 
are  exhibited  in  a  prominent  degree  only  in  the  more  typical  members  of  the 
group  ',  and  may  become  so  greatly  modified  as  to  cease  altogether  to  be  recog- 
nizable. Such  a  modification  has  been  remarkably  effected  in  the  case  of  the 
Turkish  people,  now  so  extensively  distributed.  All  the  most  learned  writers 
on  Asiatic  history  are  agreed  in  opinion,  that  the  Turkish  races  are  of  one 
common  stock;  although  at  present  they  vary  in  physical  characters  to  such  a 
degree  that,  in  some,  the  original  type  has  been  altogether  changed.  Those 
which  still  inhabit  the  ancient  abodes  of  the  race,  and  preserve  their  pastoral 
nomadic  life,  present  the  physiognomy  and  general  characteristics  which  appear 
to  have  belonged  to  the  original  Turkomans  ;  and  these  are  decided^  referable 
to  the  so-called  Mongolian  type.  Before  the  Mohammedan  era,  however,  the 
Western  Turks  or  Osmanlis  had  adopted  more  settled  habits,  and  had  made 
considerable  progress  in  civilization ;  and  their  adoption  of  the  religion  of  Islam 
incited  them  to  still  wider  extension,  and  developed  that  spirit  of  conquest 
which,  during  the  Middle  Ages,  displayed  itself  with  such  remarkable  vigor. 
The  branches  of  the  race,  which,  from  their  long  settlement  in  Europe,  have 
made  the  greatest  progress  in  civilization,  now  exhibit  in  all  essential  particulars 
the  physical  characters  of  the  European  model ;  and  these  are  particularly 
apparent  in  the  conformation  of  the  skull. — In  like  manner  we  find  that  the 
Ugrian  division,  which  migrated  towards  the  north-west  at  a  very  early  period, 
planted  a  colony  in  Europe,  which  still  tenants  the  northern  Baltic  countries, 
forming  the  races  of  Finns  and  Lapps.  In  the  time  of  Tacitus,  the  Finns  were 
as  savage  as  the  Lapps ;  but  the  former,  during  the  succeeding  ages,  became  so 
far  civilized,  as  to  exchange  a  nomadic  life  for  one  of  agricultural  pursuits,  and 
have  gradually  assimilated  with  the  surrounding  people ;  whilst  the  Lapps,  like 
the  Siberian  tribes  of  the  same  race,  have  ever  since  continued  to  be  barbarous 
nomades,  and  have  undergone  no  elevation  in  physical  characters.  The  same 
division  gave  origin  to  the  Magyars  or  Hungarians ;  a  warlike  and  energetic 


1046      OF   THE   HUMAN   FAMILY,    AND    THEIR    MUTUAL   RELATIONS. 

people,  unlike  their  kindred  in  the  North;  in  whom  a  long  abode  in  the  centre 
of  Europe  has,  in  like  manner,  developed  the  more  elevated  characters,  physical 
and  mental,  of  the  European  nations. 

1054.  The  nations  inhabiting  the  South-eastern  and  Southern  portion  of 
Asia,  also,  appear  to  have  had  their  origin  in  the  Mongolian  or  Central  Asiatic 
stock ;  although  their  features  and  form  of  skull  by  no  means  exhibit  its  cha- 
racteristic marks,  but  present  such  departures  from  it  as  are  elsewhere  observ- 
able in  races  that  are  making  advances  in  civilization.  The  conformity  to  the 
Mongolian  type  is  most  decidedly  shown  by  the  nations  (collectively  termed 
Seriform  by  Dr.  Latham)  which  inhabit  China,  Thibet,  the  Indo-Chinese 
peninsula,  and  the  base  of  the  Himalayan  range;  these  are  associated  by  certain 
linguistic  peculiarities  which  distinguish  them  from  all  other  races;  that  pri- 
mitive condition  of  human  speech,  in  which  there  is  a  total  absence  of  inflections 
indicative  of  the  relation  of  the  principal  words  to  one  another,  being  appa- 
rently preserved  with  less  change  in  the  tongues  of  these  people  than  in  those 
of  any  other.  The  Chinese  may  be  physically  characterized  as  Mongolians 
softened  down;  and  in  passing  from  China  towards  India,  through  the  Burmese 
empire,  there  is  so  gradual  a  transition  towards  the  ordinary  Hindoo  type,  that 
no  definite  line  of  demarcation  can  be  anywhere  drawn. — The  inhabitants  of  the 
great  peninsula  of  Hindostan  have  been  commonly  ranked  (as  already  remarked) 
under  the  Caucasian  race ;  both  on  account  of  their  physical  conformity  to 
that  type,  and  also  because  it  has  been  considered  that  the  basis  of  their  lan- 
guages is  Sanskritic.  It  is  certain,  however,  that  this  conclusion  is  incorrect 
with  regard  to  a  very  large  proportion  of  the  existing  population  of  India ;  and 
there  is  strong  reason  to  believe  that  no  part  of  it  bears  any  real  relation  of 
affinity  to  the  Indo-European  group  of  nations,  except  such  as  may  be  derived 
from  a  slight  intermixture.  Thus,  the  Tamulian,  which  is  the  dominant  lan- 
guage of  Southern  India,  is  undoubtedly  not  Sanskritic  in  its  origin  (although 
containing  an  infusion  of  Sanskritic  words),  but  more  closely  approximates  to 
the  Seriform  type ;  and  many  of  the  hill  tribes,  in  different  parts  of  India, 
speak  peculiar  dialects,  which,  though  mutually  unintelligible,  appear  referable 
to  the  same  stock.  Now  it  is  among  this  portion  of  the  population  of  India 
that  the  greatest  departure  presents  itself  from  the  Caucasian  type  of  cranial 
conformation,  and  the  closest  conformity  to  the  Mongolian ;  the  cheek-bones 
being  more  prominent,  the  hair  coarse,  scanty,  and  straight,  and  the  nose  flat- 
tened ;  sometimes,  also,  the  lips  are  very  thick,  and  the  jaws  project,  showing 
an  approximation  to  the  prognathous  type.  Now  in  the  opinion  of  Dr.  Latham 
and  Mr.  Norris,  the  various  dialects  of  Northern  India  (of  which  the  Hindostani 
is  the  most  extensively  spoken)  are  to  be  regarded  as  belonging,  in  virtue  of 
their  fundamental  nature,  to  the  same  group  with  those  of  High  Asia,  notwith- 
standing the  large  infusion  of  Sanskritic  words  which  they  contain;  this  infu- 
sion having  been  introduced  at  an  early  period  by  an  invading  branch  of  the  Arian 
stock,  of  whose  advent  there  is  historical  evidence,  and  whose  descendants  the 
ordinary  Hindoo  population  have  been  supposed  to  be.  According  to  this  view, 
then,  the  influence  of  the  Arian  invasion  upon  the  language  and  population  of 
Northern  India  was  very  much  akin  to  that  of  the  Norman  invasion  upon  those 
of  England;  the  number  of  individuals  of  the  invading  race  being  so  small  in 
proportion  to  that  of  the  indigenous  population,  as  to  be  speedily  merged  in  it, 
not,  however,  without  contributing  to  an  elevation  of  its  phvsical  characters ; 
and  a  large  number  of  new  words  having  been  in  like  mariner  introduced, 
without  any  essential  change  in  the  type  of  the  original  language.  And  thus 
the  only  distinct  traces  of  the  Arian  stock  are  to  be  found  in  the  Brahminical 
caste,  which  preserves  (though  with  great  corruption)  the  original  Brahminical 
religion,  and  which  keeps  up  the  Sanskrit  as  its  classical  language;  it  is  certain, 
however,  that  this  race  is  far  from  being  of  pure  descent,  having  intermingled 


PRINCIPAL    FAMILIES    OP    MANKIND.  1047 

to  a  considerable  extent  with  the  ordinary  Hindoo  population.  There  is  but 
little  to  remind  us  of  the  Mongolian  type  in  the  countenances  of  the  Hindoos, 
which  are  often  remarkable  for  a  symmetrical  beauty  that  only  wants  a  more 
intellectual  expression  to  render  them  extremely  striking ;  some  traces  of  it, 
however,  may  perhaps  be  found  in  the  rather  prominent  zygomatic  arches  which 
are  common  amongst  them ;  but  the  cranial  portion  of  the  skull  presents  no  ap- 
proach to  the  pyramidal  type,  being  often  very  regularly  elliptical.  There  is  a 
remarkable  difference  in  the  color  of  the  different  Hindoo  tribes ;  some  being 
nearly  as  dark  as  Negroes,  others  more  of  a  copper  color,  others  but  little  darker 
than  the  inhabitants  of  Southern  Europe,  whilst  others,  who  can  be  shown  to 
have  migrated  at  a  remote-  period  into  one  of  the  hilly  districts  of  Northern 
India,  have  a  fair  complexion  with  blue  eyes  and  auburn  or  even  red  hair. — 
Another  marked  departure  from  the  ordinary  Mongolian  type  is  presented  by 
the  Hyperborean  tribes  inhabiting  the  borders  of  the  Icy  Sea ;  these  have  for 
the  most  part  a  pyramidal  skull,  but  their  complexion  is  swarthy  and  their 
growth  is  peculiarly  stunted ;  and  they  form  the  link  that  connects  ordinary 
Mongolidse  with  the  Lapps  and  Finns  of  Europe  on  one  side,  and  with  the  Es- 
quimaux of  North  America  on  the  other. 

1055.  According  to  the  usual  mode  of  dividing  the  Human  family,  the  Ethi- 
opian or  Negro  stock  is  made  to  include  all  the  nations  of  Africa,  to  the  south- 
ward of  the  Atlas  range.  But,  on  the  one  hand,  there  is  good  reason  for  sepa- 
rating the  Hottentots  and  Bushmen  of  the  southern  extremity  as  a  distinct 
race;  so,  again,  the  region  north  of  the  Great  Desert  is  mostly  occupied  by  Semitic 
tribes ;  the  scattered  population  of  the  Great  Desert  itself  is  far  from  being 
Negro  in  many  of  its  features  ;  the  valley  of  the  Nile,  at  least  in  its  middle  and 
lower  portions,  including  Egypt,  Nubia,  and  even  Abyssinia,  is  inhabited  by  a 
group  of  nations  which  maybe  designated  as  Nilotic,  and  which  presents  a  series  of 
gradational  transitions  between  the  Negroes  and  Kaffres  and  the  Semitic  races ; 
a  large  portion  of  the  area  south  of  the  Equator  is  occupied  by  the  Kaffre  tribes 
and  their  allies,  which  cannot  be  truly  designated  as  Negroes ;  so  that  the  true 
Negro  area  is  limited  to  the  western  portion  of  the  African  continent,  including 
the  alluvial  valleys  of  the  Senegal,  the  Gambia,  and  the  Niger,  with  a  narrow 
strip  of  central  Africa,  passing  eastward  to  the  alluvial  regions  of  the  Upper 
Nile.  Even  within  this  area,  the  true  Negro  type  of  conformation,  such  as  we 
see  in  the  races  which  inhabit  the  low  countries  near  the  Slave  Coast — consist- 
ing in  the  combination  of  the  prognathous  form  of  skull  with  receding  fore- 
head and  depressed  nose,  thick  lips,  black  woolly  hair,  jet-black  unctuous  skin, 
and  crooked  legs — is  by  no  means  universally  prevalent ;  for  many  of  the  na- 
tions which  inhabit  it  must  be  ranked  as  sub-typical  Negroes ;  and  from  these 
the  gradation  in  physical  characters  is  by  no  means  abrupt  to  those  African 
nations  which  possess,  in  a  considerable  degree,  the  attributes  which  we  are 
accustomed  to  exclude  altogether  from  our  idea  of  the  African  race.  Thus 
the  race  of  Jolofs  near  the  Senegal,  and  the  Guber  in  the  interior  of  Sudan, 
have  woolly  hair  and  deep  black  complexions,  but  fine  forms  and  regular  fea- 
tures of  a  European  cast;  and  nearly  the  same  may  be  said  of  the  dark- 
est of  the  Kaffres  of  Southern  Africa.  The  Bechuana  Kaffres  present  a 
still  nearer  approach  to  the  European  type ;  the  complexion  being  of  a  light 
brown,  the  hair  often  not  woolly  but  merely  curled,  or  even  in  long  flowing 
ringlets,  and  the  figure  and  features  having  much  of  the  European  character. — 
There  is  no  group,  in  fact,  which  presents  a  more  constant  correspondence  be- 
tween external  conditions  and  physical  conformation  than  that  composed  of  the 
African  nations.  As  we  find  the  complexion  becoming  gradually  darker,  in 
passing  from  northern  to  southern  Europe,  thence  to  North  Africa,  thence  to  the 
borders  of  the  Great  Desert,  and  thence  to  the  intertropical  region  where  alone 
the  dullest  black  is  to  be  met  with — so  do  we  find,  on  passing  southwards  from 


1048      OF   THE    HUMAN   FAMILY,    AND   THEIR   MUTUAL   RELATIONS. 

this,  that  the  hue  becomes  gradually  lighter  in  proportion  as  we  proceed  further 
from  the  equator,  until  we  meet  with  races  of  comparatively  fair  complexions 
among  the  nations  of  Southern  Africa.  Even  in  the  intertropical  region,  high 
elevations  of  the  surface  have  the  same  effect  as  we  have  seen  them  to  produce 
elsewhere,  in  lightening  the  complexion.  Thus,  the  high  parts  of  Senegambia, 
where  the  temperature  is  moderate  and  even  cool  at  times,  are  inhabited  by 
Fulahs  of  a  light  copper  -color ;  whilst  the  nations  inhabiting  the  lower  regions 
around  them  are  of  true  Negro  blackness  :  and  nearly  on  the  same  parallel, 
but  at  the  opposite  side  of  Africa,  are  the  high  plains  of  Enarea  and  Kaffa, 
where  the  inhabitants  are  said  to  be  fairer  than  the  natives  of  Southern  Europe. 
1056.  The  languages  of  the  Negro  nations,  so  far  as  they  are  known,  seem 
to  belong  to  one  group ;  for  although  there  is  a  considerable  diversity  in  their 
vocabularies  (arising  in  great  part  from  the  want  of  written  records  which  would 
give  fixity  to  their  tongues),  yet  they  seem  to  present  the  same  grade  of  develop- 
ment and  the  same  grammatical  forms;  and  various  proofs  of  their  affinity  with 
the  Semitic  languages  have  been  developed,  these  being  afforded  by  similarity 
alike  of  roots  and  of  grammatical  construction.  The  Semitic  affinity  of  the  Negro 
nations  is  further  indicated  in  a  very  remarkable  manner  by  the  existence  of  a 
variety  of  superstitions  and  usages  among  the  Negroes  of  the  Western  coast, 
closely  resembling  those  which  prevail  also  among  the  Nilotic  races  whose 
Semitic  relations  are  most  clear,  as  well  as  among  branches  of  the  Semitic 
stock  itself;  and  thus  we  seem  to  have  adequate  proof  of  the  absence 
of  any  definite  line  of  demarcation,  in  regard  either  to  physiological  or  to  lin- 
guistic characters,  between  the  Negro  race  and  one  of  those  which  has  always 
been  considered  to  rank  as  among  the  most  elevated  forms  of  the  Caucasian 
variety. — Nor  is  there  anything  in  the  psychical  character  of  the  Negro  which 
gives  us  a  right  to  separate  him  from  other  Races  of  Mankind.  It  is  true  that 
those  races  which  have  the  Negro  character  in  an  exaggerated  degree  are  uni- 
formly in  the  lowest  stage  of  society,  being  either  ferocious  savages,  or  stupid, 
sensual,  and  indolent;  such  are  most  of  the  tribes  along  the  Slave  Coast.  But, 
on  the  other  hand,  there  are  many  Negro  states,  the  inhabitants  of  which 
have  attained  a  considerable  degree  of  improvement  in  their  social  condition; 
such  are  the  Ashanti,  the  Sulima,  and  the  Dahomans  of  Western  Africa,  also 
the  Gruber  of  Central  Sudan,  among  which  a  considerable  degree  of  civilization 
has  long  existed;  the  physical  characters  of  all  these  nations  deviate  consider- 
ably from  the  strongly  marked  or  exaggerated  type  of  the  Negro ;  and  the 
last  are  perhaps  the  finest  race  of  genuine  Negroes  on  the  whole  continent,  and 
present  in  their  language  the  most  distinct  traces  of  original  relationship  to  the 
Syro- Arabian  nations.  The  highest  civilization,  and  the  greatest  improvement 
in  physical  characters,  are  to  be  found  in  those  African  nations  which  have  adopted 
the  Mohammedan  religion ;  this  was  introduced,  three  or  four  centuries  since, 
into  the  eastern  portion  of  Central  Africa;  and  it  appears  that  the  same  people, 
which  were  then  existing  in  the  savage  condition  still  exhibited  by  the  pagan 
nations  further  south,  have  now  adopted  many  of  the  arts  and  institutions  of 
civilized  society,  subjecting  themselves  to  governments,  practising  agriculture, 
and  dwelling  in  towns  of  considerable  extent,  many  of  which  contain  10,000 
and  some  even  30,000  inhabitants;  a  circumstance  which  implies  a  consider- 
able advancement  in  industry,  and  in  the  resources  of  subsistence.  This 
last  fact  affords  most  striking  evidence  of  the  improbability  of  the  Negro 
races;  and,  taken  in  connection  with  the  many  instances  that  have  presented 
themselves,  of  the  advance  of  individuals,  under  favorable  circumstances,  to  at 
least  the  average  degree  of  mental  development  among  the  European  nations,  it 
affords  clear  proof  that  the  line  of  demarcation,  which  has  been  supposed  to 
separate  them  intellectually  and  morally  from  the  races  that  have  attained  the 
greatest  elevation,  has  no  more  real  existence  than  that  which  has  been  sup- 


PRINCIPAL   FAMILIES    OF   MANKIND.  1049 

posed  to  be  justified  by  a  difference  in  physical  characters,  and  of  which  the 
fallacy  has  been  previously  demonstrated. 

1057.  The  southern  portion  of  the  African  continent  is  inhabited  by  a  group 
of  nations  which,  as  already  mentioned,  recede,  more  or  less  decidedly,  from 
the  Negro  type  in  physical  characters,  and  which  seem  connected  together  by 
essential  community  of  language,  as  branches  of  the  stock  of  which  the  Kaffres 
may  be  considered  the  stem.     In  this  warlike  nomadic  people,  which  inhabit 
the  eastern  parts  of  South  Africa,  to  the  northward  of  the  Hottentot  country, 
so  great  a  departure  from  the  ordinary  Negro  type  presents  itself,  that  many 
travellers  have  assigned  to  them  a  different  origin.    The  degree  of  this  departure, 
however,  varies  greatly  in  the  different  Kaffre  tribes ;  for,  whilst  some  of  them 
are  black,  woolly-headed,  and  decidedly  prognathous,  so  as  obviously  to  approach 
the  modified  Negroes  of  Congo  in  general  aspect,  others  recede  considerably 
from  the  typical  prognathous  races,  both  in  complexion,  features,  and  form  of 
head,  presenting  a  light-brown  color,  high  forehead,  prominent  nose,  and  a  tall, 
robust,  well-shaped  figure.     The  thick  lips  and  black  frizzled  hair  are  generally 
retained,  however ;  but  the  hair  is  sometimes  of  a  reddish  color,  and  becomes 
flowing;    and  the  features   may  present  a  European   cast.     Even  among  the 
tribes  which  depart  most  widely  from  the  Negro  type,  however,  individuals  are 
found  who  present  a  return  to  it ;   and  it  is  interesting  to  remark  that  the 
people  of  Delagoa  Bay,  though  of  the  Kaffre  race  (as  indicated  by  their  lan- 
guage), having  been  degraded  by  subjugation,  approach  the  people  of  the  Guinea 
Coast  in  their  physical  characters.     In  fact,  between  the  most  elevated  Kaffre 
and  the  most  degraded  Negro,  every  possible  gradation  of  physical  and  psychical 
characters  is  presented  to  us,  as  we  pass  northwards  and  westwards  from  Kaf- 
fraria  towards  the  Guinea  Coast;  and  we  meet  with  a  similar  transition,  although 
not  carried  to  so  great  an  extent,  as  we  pass  up  the  eastern  coast. — The  lan- 
guages of  the  Kaffres  and  other  allied  tribes  are  distinguished  by  a  set  of 
remarkable  characters,  which  have  been  considered  as  isolating  them  from  other 
African  tongues.     According  to  Dr.  Latham,  however,  these  peculiarities  are 
not  so  far  without  precedent  elsewhere,  as  to  establish  the  very  decided  line  of 
demarcation  which  some  have  attempted  to  draw ;  and  may  be  regarded,  in  fact, 
as  resulting  from  the  fuller  development  of  tendencies  which  manifest  them- 
selves in  other  African  languages. 

1058.  The  Bushmen  or  Bosjesmen  of  South  Africa  are  generally  regarded  as 
presenting  the  most  degraded  and  miserable  condition  of  which  the  human  race 
is  capable;  and  they  have  been  supposed  to  present  resemblances  in  physical 
characters  to  the  higher  Quadrumana.     Yet  there  is  distinct  evidence,  that  this 
degraded  race  is  but  a  branch  or  subdivision  of  the  once  extensive  nation  of 
Hottentots ;  and  that  its  present  condition  is  in  great  part  due  to  the  hardships 
to  which  it  has  been  subjected,  partly  in  consequence  of  European  colonization. 
The  Hottentot  race  differs  from  all  other  South  African  nations,  both  in  language 
and  in  physical  conformation.     The  language  cannot  be  shown  to  possess  distinct 
affinities  with  any  other  stock;1  but  in  bodily  structure  there  is  a  remarkable 

1  It  is  considered  by  some,  that  the  Hottentot  language  is  a  degraded  Kaffre,  as  the 
Bushman  language  is  a  degraded  Hottentot;  but  the  Author  is  informed  by  Mr.  Norris 
that  he  sees  no  valid  ground  for  this  assumption,  the  affinities  of  the  Hottentot  language 
being  rather,  in  his  opinion,  with  the  languages  of  High  Asia,  although  the  connecting 
links  are  extremely  slight.  Such  as  they  are,  however,  they  tend  to  confirm  an  idea 
suggested  to  the  Author,  some  years  since,  by  the  marked  reproduction  of  so  many  Mon- 
golian characters  in  the  Hottentot  race — that  it  is  the  remnant  of  a  migration  from 
Asia  earlier  than  that  in  which  the  great  bulk  of  the  African  nations  have  their  origin ; 
and  that  it  has  been  driven  down  to  the  remotest  corner  of  the  continent,  just  as  the  abo- 
riginal (Mongolian)  population  of  south-western  Europe  seems  to  have  been  driven  back 
by  the  Indo-European  immigration  ($  1050). 


1050      OF   THE    HUMAN    FAMILY,    AND    THEIR    MUTUAL   RELATIONS. 

admixture  of  the  characters  of  the  Mongolian  with  those  of  the  Negro.  Thus 
the  face  presents  the  very  wide  and  high  cheek-bones,  with  the  oblique  eyes  and 
flat  nose,  of  the  Northern  Asiatics ;  at  the  same  time  that,  in  the  somewhat 
prominent  muzzle  and  thick  lips,  it  resembles  the  countenance  of  the  Negro. 
The  complexion  is  of  a  tawny  buff  or  fawn  color,  like  the  black  of  the  Negroes 
diluted  with  the  olive  of  the  Mongols.  The  hair  is  woolly,  like  that  of  the 
Negroes,  but  it  grows  in  small  tufts  scattered  over  the  surface  of  the  scalp  (like 
a  scrubbing-brush),  instead  of  covering  it  uniformly;  thus  resembling  in  its 
comparative  scantiness  that  of  the  Northern  Asiatics.  It  is  most  interesting  to 
observe  this  remarkable  resemblance  in  physical  characters,  between  the  Hot- 
tentots and  the  Mongolian  races,  in  connection  with  the  similarity  that  exists 
between  the  circumstances  under  which  .they  respectively  live;  and  it  is  not  a 
little  curious  that  the  Hottentot,  as  the  Mongol,  should  be  distinguished  by  the 
extraordinary  acuteness  of  his  vision.  No  two  countries  can  be  more  similar 
than  the  vast  steppes  of  Central  Asia,  and  the  karroos  of  Southern  Africa;  and 
the  proper  inhabitants  of  each  are  nomadic  races,  wandering  through  deserts 
remarkable  for  the  wide  expansion  of  their  surface,  their  scanty  herbage,  and 
the  dryness  of  their  atmosphere,  and  feeding  upon  the  milk  and  flesh  of  their 
horses  and  cattle.  Of  the  original  pastoral  Hottentots,  however,  very  few  now 
remain.  They  have  been  gradually  driven,  by  the  encroachments  of  European 
colonists  and  by  internal  wars  with  each  other,  to  seek  refuge  among  the  inac- 
cessible rocks  and  deserts  of  the  interior;  and  they  have  thus  been  converted 
from  a  mild,  unenterprising  race  of  shepherds,  into  wandering  hordes  of  fierce, 
suspicious,  and  vindictive  savages,  treated  as  wild  beasts  by  their  fellow-men, 
until  they  have  become  really  assimilated  to  wild  beasts  in  their  habits  and  dis- 
positions. This  transformation  has  taken  place,  under  the  observation  of  eye- 
witnesses, in  the  Koranas,  a  tribe  of  Hottentots  well  known  to  have  been  pre- 
viously the  most  advanced  in  all  the  improvements  which  belong  to  pastoral 
life;  for  having  been  plundered  by  their  neighbors,  and  driven  out  into  the 
wilderness  to  subsist  upon  wild  fruits,  they  have  adopted  the  habits  of  the 
Bushmen,  and  have  become  assimilated  in  every  essential  particular  to  that 
miserable  tribe.  It  appears,  however,  from  the  inquiries  of  Dr.  Andrew  Smith, 
that  this  process  of  degradation  has  been  in  operation  quite  independently  of 
external  agencies;  nearly  all  the  South  African  tribes  who  have  made  any 
advances  in  civilization,  being  surrounded  by  more  barbarous  hordes,  whose 
abodes  are  in  the  wildernesses  of  mountains  and  forests,  and  who  constantly 
recruit  their  numbers  by  such  fugitives  as  crime  and  destitution  may  have  driven 
from  their  own  more  honest  and  more  thriving  communities;  and  these  people 
vary  their  mode  of  speech  designedly,  and  even  adopt  new  words,  in  order  to 
make  their  meaning  unintelligible  to  all  but  the  members  of  their  own  com- 
munity. All  this  has  its  complete  parallel  in  the  very  midst  of  our  own  or  any 
other  highly  civilized  community;  all  our  large  towns  containing  spots  nearly 
as  inaccessible  to  those  unacquainted  with  them  as  are  the  rude  caves  or  clefts 
of  hills,  or  the  burrows  scooped  out  of  the  level  karroo,  in  which  the  wretched 
Bushman  lies  in  wait  for  his  prey;  and  these  being  tenanted  by  a  people  that 
have  been  well  characterized  as  les  classes  danger euses,  which,  as  often  as  the 
arm  of  the  law  is  paralyzed,  issue  forth  from  the  unknown  deserts  within  which 
they  lurk,  and  rival  in  their  fierce  indulgence  of  the  most  degrading  passions, 
and  in  their  excesses  of  wanton  cruelty,  the  most  terrible  exhibitions  of  barba- 
rian inhumanity.  Such  outcasts,  in  all  nations,  purposely  adopt,  like  the  Bush- 
men, "a  flash"  language;  and  in  their  general  character  and  usages,  there  is  a 
most  striking  parallel.1 

1059.  The  American  nations,  taken  collectively,  form  a  group  which  appears 

1  See  "London  Labor  and  London  Poor,"  p.  2. 


PRINCIPAL   FAMILIES   OP    MANKIND.  1051 

to  have  existed  as  a  separate  family  of  nations  from  a  very  early  period  in  the 
world's  history.  They  do  not  form,  however,  so  distinct  a  variety,  in  regard  to 
physical  characters,  as  some  anatomists  have  endeavored  to  prove ;  for,  although 
certain  peculiarities  have  been  stated  to  exist  in  the  skulls  of  the  aboriginal 
Americans,  yet  it  is  found,  on  a  more  extensive  examination,  that  these  peculi- 
arities are  very  limited  in  their  extent — the  several  nations  spread  over  this  vast 
continent  differing  from  each  other  in  physical  peculiarities  as  much  as  they  do 
from  those  of  the  Old  World,  so  that  no  typical  form  can  be  made  out  among 
them.  In  regard  to  complexion,  again,  it  may  be  remarked  that,  although  the 
native  Americans  have  been  commonly  characterized  as  "red  men,"  they  are  by 
no  means  invariably  of  a  red  or  coppery  hue,  some  being  as  fair  as  many  Euro- 
pean nations,  others  being  yellow  or  brown,  and  others  nearly,  if  not  quite,  as 
black  as  the  Negroes  of  Africa;  whilst,  on  the  other  hand,  there  are  tribes 
equally  red,  and  perhaps  more  deserving  that  epithet,  in  Africa  and  Polynesia. — 
In  spite  of  all  this  diversity  of  conformation,  it  is  believed  that  the  structure  of 
their  languages  affords  a  decided  and  clearly  marked  evidence  of  relationship 
between  them.  The  words,  and  even  the  roots,  may  differ  entirely  in  the  differ- 
ent groups  of  American  nations;  but  there  is  a  remarkable  similarity  in  gram- 
matical construction  amongst  them  all,  which  is  of  a  kind  not  only  to  demonstrate 
their  mutual  affinity,  but  to  separate  them  completely  from  all  known  languages 
of  the  Old  Continent.  Notwithstanding  their  diversities  in  mode  of  life,  too, 
there  are  peculiarities  of  mental  character,  as  well  as  a  number  of  ideas  and 
customs  derived  from  tradition,  which  seem  to  be  common  to  them  all,  and 
which,  for  the  most  part,  indicate  a  former  elevation  in  the  scale  of  civilization, 
that  has  left  its  traces  among  them  even  in  their  present  degraded  condition, 
and  that  still  distinguishes  them  from  the  sensual,  volatile,  and  almost  animal- 
ized  savages  that  are  to  be  met  with  in  many  parts  of  the  Old  Continent. — The 
Esquimaux  constitute  an  exception  to  all  general  accounts  of  the  physical  cha- 
racters of  the  American  nations;  for  in  the  configuration  of  their  skulls,  as  also 
in  their  complexion  and  general  physiognomy,  they  conform  to  the  Mongolian 
type,  even  presenting  it  in  an  exaggerated  degree.  Their  wide  extension  along 
the  whole  northern  coast  of  America,  and  the  near  proximity  of  this  coast  to 
Kamschatka,  certainly  lend  weight  to  the  idea  that  they  derive  their  origin 
from  the  Northern  Asiatic  stock;  but,  on  the  other  hand,  they  have  a  marked 
affinity,  in  regard  to  language,  to  the  other  American  nations.  The  Athapascan 
Indians,  various  tribes  of  which  inhabit  the  country  south  of  the  Esquimaux 
country,  seem  intermediate  in  physical  characters,  as  they  are  in  geographical 
position,  between  the  Esquimaux  and  the  ordinary  Americans.  They  have  a 
tradition  which  seems  to  indicate  that  they  are  derived  from  the  North-Eastern 
Asiatics,  with  whom  they  have  many  points  of  accordance  in  dress  and  manners. 
1060.  It  now  remains  for  us  to  notice  the  Oceanic  races,  which  inhabit  the 
vast  series  of  islands  scattered  through  the  great  ocean,  that  stretches  from 
Madagascar  to  Easter  Island.  There  is  no  part  of  the  world  which  affords  a 
greater  variety  of  local  conditions  than  this,  or  which  more  evidently  exhibits 
the  effects  of  physical  agencies  on  the  organization  of  the  human  body.  More- 
over, it  affords  a  case  for  the  recognition  of  affinities  by  means  of  language,  that 
possesses  unusual  stability;  since  the  insulated  position  of  the  various  tribes  that 
people  the  remote  spots  of  this  extensive  tract  prevents  them  from  exercising 
that  influence  upon  each  other's  forms  of  speech  which  is  to  be  observed  in  the 
case  of  nations  united  by  local  proximity  or  by  frequent  intercourse.  Tried  by 
this  test,  it  is  found  that  the  different  groups  of  people,  inhabiting  the  greater 
part  of  these  insular  tracts,  are  more  nearly  connected  together,  although  so 
widely  scattered,  and  so  diverse  in  physical  characters,  than  most  of  the  families 
of  men  occupying  continuous  tracts  of  land  on  the  great  continents  of  the  globe. 
The  inhabitants  of  Oceania  seem  divisible  into  two  principal  groups,  which  are 


1052      OF   THE    HUMAN    FAMILY,    AND   THEIR   MUTUAL   RELATIONS. 

probably  to  be  regarded  as  having  constituted  distinct  races  from  a  very  early 
period;  these  are  the  Malayo-Polynesian  race,  and  the  Pelagian  Negroes  or 
Negritos. 

1061.  The  Malayo-Polynesian  group  is  by  far  the  more  extensive  of  the  two ; 
and  comprehends  the  inhabitants  of  the  greater  part  of  the  Indian  and  Poly- 
nesian Archipelagoes,  with  the  peninsula  of  Malacca  (which  is  the  centre  of  the 
Malays  proper),  and  the  inhabitants  of  Madagascar.     These  are  all  closely  united 
by  affinities  of  language.     The  proper  Malays  bear  a  strong  general  resemblance 
to  the  Mongolian  races,  and  this  resemblance  is  shared,  in  a  greater  or  less  degree, 
by  most  of  the  inhabitants  of  the  Indian  Archipelago.    They  are  of  a  darker  com- 
plexion, as  might  be  expected  from  their  proximity  to  the  equator ;  but  in  this 
complexion,  yellow  is  still  a  large  ingredient.     The  Polynesian  branch  of  the 
group  presents  a  much  wider  diversity ;  and  if  it  were  not  for  the  community  of 
language,  it  might  be  thought  to  consist  of  several  races,  as  distinct  from  each 
other  as  from  the  Malayan  branch.     Thus  the  Tahitians  and  Marquesans  are  tall 
and  well  made;  their  figures  combine  grace  and  vigor;  their  skulls  are  usually 
remarkably  symmetrical ;  and  their  physiognomy  presents  much  of  the  European 
cast,  with  a  very  slight  admixture  of  the  features  of  the  Negro.     The  complex- 
ion, especially  in  the  females  of  the  higher  classes,  who  are  sheltered  from  the 
wind  and  sun,  is  of  a  clear  olive  or  brunette,  such  as  is  common  among  the 
natives  of  Central  and  Southern  Europe ;  and  the  hair,  though  generally  black, 
is  sometimes  brown  or  auburn,  or  even  red  or  flaxen.     Among  other  tribes,  as 
the  New  Zealanders,  and  the  Tonga  and  Friendly  Islanders,  there  are  greater 
diversities  of  conformation  and  hue ;  some  being  finely  proportioned  and  vigorous, 
others  comparatively  small  and  feeble ;  some  being  of  a  copper-brown  color,  others 
nearly  black,  others  olive,  and  others  almost  white.     In  fact,  if  we  once  admit 
a  strongly  marked  difference  in  complexion,  features,  hair,  and  general  con- 
figuration, as  establishing  a  claim  to  original  distinctness  of  origin,  we  must 
admit  the  application  of  this  hypothesis  to  almost  every  group  of  islands  in  the 
Pacific; — an  idea  of  which  the  essential  community  of  language  seems  to  afford 
a  sufficient  refutation.     Among  the  inhabitants  of  Madagascar,  too,  all  of  which 
speak  dialects  of  the  same  language,  some  bear  a  strong  resemblance  to  the 
Malayan  type,  whilst  others  present  approaches  to  that  of  the  Negro. 

1062.  The  Pelagian-Negro  races  must  be   regarded  as  a  group  altogether 
distinct  from  the  preceding ;  having  a  marked  diversity  of  language ;  and  pre- 
senting more  decidedly  than  any  of  the  Malayo-Polynesians  the  characters  of 
the  Negro  type.      They  form  the  predominating  population  of  New  Britain, 
New  Ireland,  the  Louisiade  and  Solomon  Isles,  of  several  of  the  New  Hebrides, 
and  of  New  Caledonia ;  and  they  seem  to  extend  westwards  into  the  mountain- 
ous interior  of  the  Malayan  Peninsula,  and  into  the  Andaman  Islands  in  the 
Bay  of  Bengal.     The  Tasmanians,  or  aborigines  of  Van  Dieman's  Land,  which 
are  now  almost  completely  exterminated,  undoubtedly  belong  to  this  group.   Very 
little  is  known  of  them,  except  through  the  reports  of  the  people  of  Malayo- 
Polynesian  race  inhabiting  the  same  islands;    but  it  appears  that,  generally 
speaking,  they  have  a  very  inferior  physical  development,  and  lead  a  savage  and 
degraded  life.     There  is  considerable  diversity  of  physical  characters  among 
them;  some  approximating  closely  in  hair,  complexion,  and  features,  to  the 
Guinea  Coast  Negroes ;  whilst  others  are  of  yellower  tint,  straight  hair,  and  better 
general  development.     The  Papuans,  who  inhabit  the  northern  coast  of  New 
Gluineaand  some  adjacent  islands,  and  who  are  remarkable  for  their  large  bushy 
masses  of  half-woolly  hair,  have  been  supposed  to  constitute  a  distinct  race  ;  but 
there  is  little  doubt  that  they  are  of  hybrid  descent,  between  the  Malays  and 
the  Pelagian  Negroes. — To  this  group  we  are  probably  to  refer  the  Alfourous, 
or  Alforian  race,  which  are  considered  by  some  to  be  the  earliest  inhabitants  of 
the  greater  part  of  the  Malayan  Archipelago,  and  to  have  been  supplanted  by 


PRINCIPAL   FAMILIES   OF   MANKIND.  1053 

the  more  powerful  people  of  the  preceding  races,  who  have  either  extirpated 
them  altogether,  or  have  driven  them  from  the  coasts  into  the  mountainous  and 
desert  parts  of  the  interior.  They  are  yet  to  be  found  in  the  central  parts  of 
the  Moluccas  and  Philippines ;  and  they  seem  to  occupy  most  of  the  interior 
and  southern  portions  of  New  Guinea,  where  they  are  termed  Endamenes. 
They  are  of  very  dark  complexion ;  but  their  hair,  though  black  and  thick,  is 
lank.  They  have  a  peculiarly  repulsive  physiognomy ;  the  nose  is  flattened,  so 
as  to  give  the  nostrils  an  almost  transverse  position;  the  cheek-bones  project; 
the  eyes  are  large,  the  teeth  prominent,  the  lips  thick,  and  the  mouth  wide. 
The  limbs  are  long,  slender,  and  misshapen.  From  the  close  resemblance  in 
physical  characters  between  the  Endamenes  of  New  Guinea  and  the  aborigines 
of  New  Holland,  and  from  the  proximity  between  the  adjacent  coasts  of  these  two 
islands,  it  may  be  surmised  that  the  latter  belong  to  the  Alforian  race ;  but  too 
little  is  known  of  the  language  of  either  to  give  this  inference  a  sufficient  sta- 
bility. In  the  degradation  of  their  condition  and  manner  of  life,  the  savages 
of  New  Holland  fully  equal  the  Bushmen  of  South  Africa;  and  it  is  scarcely 
possible  to  imagine  human  beings  existing  in  a  condition  more  nearly  resem- 
bling that  of  brutes.  But  there  is  reason  to  believe  that  the  tribes  in  closest 
contact  with  European  settlers  are  more  miserable  and  savage  than  those  of  the 
interior;  and  even  with  respect  to  these,  increasing  acquaintance  with  their  lan- 
guage, and  a  consequent  improved  insight  into  their  modes  of  thought,  tend  to 
raise  the  very  low  estimate  which  had  been  formed  and  long  maintained  in  re- 
gard to  their  extreme  mental  degradation.  The  latest  and  most  authentic  state- 
ments enable  us  to  recognize  among  them  the. same  principles  of  a  moral  and 
intellectual  nature,  which,  in  more  cultivated  tribes,  constitute  the  highest  en- 
dowments of  humanity;  and  thus  to  show  that  they  are  not  separated,  by  any 
impassable  barrier,  from  the  most  civilized  and  elevated  nations  of  the  globe. 
There  are  many  indications,  indeed,  that  the  Negrito  race  is  not  so  radically  dis- 
tinct from  the  Malayo-Polynesian,  as  the  marked  physical  dissimilarity  of  their 
respective  types,  and  the  apparent  want  of  conformity  between  their  languages, 
would  make  it  appear.  For  as,  on  the  one  hand,  some  of  the  subdivisions  of 
the  latter  present  a  decided  tendency  towards  that  prognathous  character  and 
depth  of  complexion  which  are  typical  of  the  former,  so  among  the  former  do 
we  not  unfrequently  meet  with  a  lighter  shade  of  skin,  a  greater  symmetry  of 
skull,  and  a  considerable  improvement  in  form  and  feature.  And  although  no 
very  close  relationship  can  be  discovered  between  the  Negrito  and  Malayo-Poly- 
nesian languages,  yet  it  has  been  pointed  out  by  Mr.  Norris  that  a  much  more 
decided  relationship  exists  between  the  Australian  and  Tamulian  (§  1054);  and 
remote  as  this  connection  seems,  the  circumstance  adds  weight  to  the  idea  that 
the  native  Australians  (with  other  Negrito  tribes)  are  an  offset  from  that  south- 
ern branch  of  the  great  nomadic  stock  of  Central  Asia  which  seems  early  to 
have  spread  itself  through  the  Indo-Chinese  and  the  Indian  Peninsulas,  and  to 
have  even  there  shown  an  approximation  to  the  prognathous  type. 

1063.  Looking,  then,  to  the  great  diversity  which  exists  among  the  subordi- 
nate groups  of  which  both  these  divisions  consist,  and  their  tendency  to  mutual 
approximation,  it  cannot  be  shown  that  any  sufficient  reason  exists  for  isolating 
them  from  each  other ;  and,  as  already  remarked,  there  seems  no  medium  be- 
tween the  supposition  that  each  island  had  its  aboriginal  pair  or  pairs,  and  the 
doctrine  that  the  whole  of  Oceania  has  been  peopled  from  a  common  stock. 
Looking,  again,  to  the  very  marked  approximation  which  is  presented  by  certain 
Oceanic  tribes  to  the  Mongolian  type,  and  this  in  a  locality  which,  on  other 
grounds,  might  be  regarded  as  having  received  the  first  stream  of  migration, 
the  possibility,  to  say  the  least,  can  scarcely  be  denied,  that  the  mainland  fur- 
nished the  original  stock,  which  has  undergone  various  transformations  subse- 
quently to  its  first  dispersion ;  these  having  been  the  result  of  climatic  influence 


1054  OF  DEATH. 

and  mode  of  life,  and  having  been  chiefly  influenced  as  to  degree  by  the  length 
of  time  during  which  the  transforming  causes  have  been  in  operation.  At  any 
rate,  it  may  be  safely  affirmed  that  there  is  no  physical  peculiarity  which  entitles 
the  Oceanic  races  to  rank  as  a  group  which  must  have  necessarily  had  an  origi- 
nal stock  distinct  from  that  of  the  continental  nations. 


CHAPTER   XXI. 

OF   DEATH. 

1064.  IT  seems  inherent  in  the  very  nature  of  Vital  Action,  that  it  can  only 
be  sustained  during  a  limited  period  by  any  Organized  body ;  for  although  the 
duration  of  certain  structures  may  be   prolonged,  and  their  vital   properties 
retained,  almost  indefinitely,  yet  this  is  only  when  the  withdrawal  of  all  extrane- 
ous  agencies  has  reduced  them  to  a  condition  of  complete  inactivity  (§  114). 
The  Organized  fabric,  in  fact,  is  at  the  same  time  the  instrument  whereby  Vital 
Force  is  exercised,  and  the  subject  of  its  operation ;  and  of  this  operation,  as 
we  have  seen  (§  114),  decline  is  no  less  a  constituent  part  than  development, 
and  Death  is  its  necessary  sequence.     Hence,  in  the  performance  of  each  one 
of  those  Functions  whose  aggregate  makes  up  the  Life  of  Man,  the  particu- 
lar organ  which  ministers  to  that  function  undergoes  a  certain  loss  by  the 
decline  and  death  of  its  component  tissues ;  and  this  the  more  rapidly,  in  pro- 
portion to  the  activity  of  the  changes  which  are  effected  by  their  instrumentality. 
But  if  the  regenerative  processes  be  also  performed  with  due  vigor,  no  deteri- 
oration of  the  organ  is  manifested,  since  every  loss  of  substance  is  compensated 
by  the  production  of  an  equivalent  amount  of  new  and  similar  tissue.     This 
regenerative  power,  however,  gradually  diminishes  with  the  advance  of  years ; 
and  thus  it  happens  that  the  entire  organism  progressively  deteriorates  (§  133), 
and  that  Death  at  last  supervenes  from  a  general  failure  of  the  vital  powers,  rather 
than  from  the  perversion  or  cessation  of  any  one  class  of  actions  in  particular. 

1065.  But  Death  may  occur  at  any  period  of  Life,  from  some  local  interrup- 
tion produced  by  disease  or  injury  in  the  regular  sequence  of  vital  actions ;  such 
interruption  extending  itself  from  the  part  in  which  it  commences  to  the  organism 
in  general,  in  virtue  of  that  intimate  mutual  dependence  of  one  function  upon 
another  which  is  characteristic  of  all  the  higher  orders  of  living  beings.     The 
death  of  the  body,  as  a  whole,  which  may  be  appropriately  designated  Somatic1 
death,  becomes  a  necessary  consequence  of  the  death  of  a  certain  part  of  it,  or 
Molecular  death,  only  when  the  cessation  of  activity  in  the  latter  interferes  with 
the  elaboration,  the  circulation,  or  the  depuration  of  the  Blood,  which  supplies  not 
merely  the  nutritive  pabulum  to  every  part  of  the  organism,  but  also  the  oxygen 
which  is  essential  to  the  activity  of  the  nervo-muscular  apparatus.    Thus,  even  in 
the  higher  animals,  the  death  or  removal  of  the  limbs,  although  they  may  consti- 
tute (as  in  Man)  a  large  proportion  of  the  fabric,  is  not  necessarily  fatal ;  because 
it  involves  no  interruption,  either  in  the  nutritive  operations  of  the  viscera,  or 
in  the  sensorial  functions  of  the  brain.2     On  the  other  hand,  the  destruction  of 

1  This  terra  was  first  suggested  by  Dr.  Prichard  in  place  of  the  less  accurate  term  "  sys- 
temic," which  was  previously  in  use.  (See  "Cyclop,  of  Anat.  andPhysiol.,"vol.  x.  p.  791.) 

2  The  Author  has  been  informed  by  Dr.  Daniell  that  it  is  not  at  all  uncommon,  in  Ne- 
groes who  are  in  the  last  stage  of  the  adynamic  fevers  of  the  African  coast,  for  death  and 
decomposition  to  extend  gradually  upwards  from  the  extremities  to  the  trunk  ;  so  that  the 


OF   DEATH.  1055 

a  certain  minute  portion  of  the  nervous  centres,  or  such  a  lesion  of  the  heart's 
structure  as  would  be  trivial  in  almost  any  other  organ,  may  be  the  occasion  of 
immediate  death  j  because  these  changes  arrest  the  respiratory  movements,  'or 
interfere  directly  with  the  action  of  the  heart,  so  as  to  bring  the  flow  of  blood 
to  a  stand.  It  sometimes  happens,  however,  that  life  may  be  prolonged,  after 
the  death  or  removal  of  some  important  organ,  in  consequence  of  the  pWer 
which  some  other  possesses  of  discharging  its  function  ]  thus  we  find  that,  in 
Man,  the  kidneys  seem  occasionally  to  take  upon  themselves  the  elimination 
of  the  constituents  of  bile  from  the  blood  (§  622) ;  and  in  the  Frog,  the  skin 
can  perform  part  of  the  office  of  the  Lungs,  so  as  to  effect  the  aeration  of  the 
blood  in  a  sufficient  degree  to  prolong  life  for  some  time,  unless  the  temperature 
be  elevated.1 — But  although  the  vital  activity  of  every  part  of  the  body  is 
dependent  upon  a  due  supply  of  circulating  fluid,  yet  this  dependence  is  usually 
not  so  close  as  to  involve  the  immediate  suspension  of  vital  activity  in  every 
part,  whenever  the  general  Circulation  shall  have  been  brought  to  a  stand.  For 
we  have  distinct  evidence  of  the  persistence  of  vital  changes  in  various  organs 
and  tissues  of  the  body,  after  the  death  of  the  body  at  large ;  as  is  manifested 
in  the  performance  of  ciliary  and  of  muscular  movements  (§§  231,  328),  in 
acts  of  secretion  (§  945)  and  perhaps  even  of  nutrition,  in  the  maintenance  of 
the  local  circulation  (§  522),  and  in  the  generation  of  animal  heat  (§  652) ; 
and  the  fact  is  even  yet  more  remarkably  manifested  in  the  reunion  (even  after 
the  lapse  of  some  hours)  of  parts  that  have  been  entirely  severed,  such  as  fingers 
or  toes,  noses  or  ears,  by  adhesion  between  the  cut  surfaces  when  brought  into 
apposition,  which  could  not  take  place  if  the  severed  part  were  dead. 

1066.  The  permanent  and  complete  cessation  of  the  Circulating  current,  which 
essentially  constitutes  Somatic  Death,  may  be  directly  or  indirectly  consequent 
upon  several  distinct  causes. — In  the  first  place,  it  may  be  due  to  failure  in  the 
propulsive  power  of  the  Heart,  which  constitutes  Syncope.  This  failure  "may 
occur  either  (a)  in  consequence  of  a  loss  of  the  proper  irritability  of  the  Mus- 
cular tissue,  or  (6)  through  the  supervention  of  a  "  tonic  spasm/'  the  organ 
remaining  rigidly  contracted  without  its  usual  alternation  of  relaxation.  The 
phenomena  attending  death  in  the  two  cases  are  not  dissimilar,  when  the  loss 
of  irritability  is  sudden  and  immediate  (as  when  it  arises  from  violent  impres- 
sions on  the  nervous  system) ;  for  the  individual  suddenly  turns  pale,  falls  back 
or  drops  down,  and  expires  with  one  gasp.  But  under  the  former  condition, 
the  heart  is  found  flabby,  sometimes  empty,  sometimes  distended  with  blood, 
both  cavities  being  equally  filled ;  whilst  in  the  latter,  the  heart  is  contracted 
and  hard,  containing  little  or  no  blood,  as  when  in  the  state  of  rigor  mortis 
(§  335). — The  cause  of  the  loss  of  irritability,  when  sudden,  usually  lies  in  the 
influence  of  a  "  shock"  -transmitted  through  the  Nervous  system,  and  originat- 
ing either  in  some  severe  lesion  of  its  central  organs  or  of  its  peripheral  expan- 
sion (§  321),  or  in  a  deficiency  of  its  supply  of  blood  or  diminution  of  its  usual 
pressure  (such  as  is  produced  by  rapid  detraction  of  blood,  especially  in  the 
erect  posture,  by  the  rapid  removal  of  the  fluid  in  ascites  without  the  substitu- 
tion of  artificial  pressure,  or  by  suddenly  rising  into  the  erect  posture  after  pro- 
longed recumbency,51  still  more,  after  long  stooping),  or  in  some  powerful  mental 

former  may  be  in  a  state  of  absolute  putrescence,  before  the  respiration  and  circulation  have 
been  brought  to  a.  stand ;  and  he  learns  from  his  friend  Prof,  Jackson,  of  Philadelphia, 
that  he  has  more  than  once  witnessed  the  same  occurrence. 

•  That  such  cannot  take  place  in  Man,  is  due  not  merely  to  the  far  less  complete  adapta- 
tion of  his  skin  for  the  aeration  of  the  blood,  but  also  to  the  difference  in  the  type  of  his 
circulation,  which  causes  the  arrest  of  blood  in  the  pulmonary  vessels  to  produce  a  stagna- 
tion of  the  entire  current. 

2  Hence  it  is  that  great  caution  should  be  exercised,  in  allowing  patients  who  are  con- 
valescent from  acute  diseases  to  rise  into  the  erect  position ;  many  cases  of  fatal  syncope 


1056  OF   DEATH. 

emotion,  either  exciting  or  depressing.  A  more  gradual  effect  of  the  same  kind 
is  produced  by  Jesions  of  the  internal  organs  (such  as  rupture  of  the  uterus), 
which  often  prove  fatal  by  the  general  "  collapse"  thus  induced,  rather  than  by 
the  disturbance  which  takes  place  in  their  own  proper  functions;  and  this  seems 
to  be  the  usual  modus  operandi  of  corrosive  poisons,  whose  effect  upon  the 
heart's  action  resembles  that  produced  by  severe  burns  of  the  surface  in  children. 
The  influence  of  the  proper  sedative  poisons,  however — such  as  digitalis,  tobacco, 
aconite,  and  upas — seems  to  be  directly  exerted,  through  the  Blood,  upon  the 
tissue  of  the  heart  itself ;  and  the  same  is  probably  the  case  with  some  of  those 
11  morbid  poisons"  whose  introduction  into  the  system  gives  rise  to  diseases  of 
the  most  intensely  adynamic  type,  such  as  Malignant  Cholera,  in  which  the 
" collapse"  is  out  of  all  proportion  to  any  local  lesion.  But  again,  the  loss  of 
the  Heart's  irritability  may  be  a  gradual  process,  resulting  from  the  deteriora- 
tion of  its  tissue  by  fatty  degeneration  or  by  simple  atrophy  ;  and  this  last  con- 
dition may  be  due  to  deficiency  of  blood,  as  happens  in  chronic  starvation  and 
diseases  of  exhaustion,  in  which  the  failure  of  the  circulation  seems  due  to  the 
weakening  of  the  heart's  power  and  to  the  lowering  of  the  quantity  and  quality 
of  the  blood,  as  concurrent  causes,  the  condition  thus  induced  being  appropri- 
ately designated  Asthenia.  In  all  cases  it  is  to  be  observed,  that  when  the  Vital 
powers  have  been  previously  depressed,  a  much  slighter  impression  on  the  Nerv- 
ous system  is  adequate  to  produce  Syncope,  than  would  be  required  when  it 
is  in  a  state  of  full  vigor. — The  causes  of  the  tonic  spasm  of  the  heart  have  not 
been  clearly  made  out,  but  it  seems  producible,  like  the  more  common  form  of 
Syncope,  by  agencies  operating  through  the  Nervous  system;  thus  it  has  super- 
vened upon  the  ingestion  of  a  large  quantity  of  cold  water  into  the  stomach. 

1067.  Somatic  Death  may  be  occasioned,  secondly,  by  an  obstruction  to  the 
flow  of  blood  through  the  capillaries  of  the  lungs,  constituting  Asphyxia  (§  574) ; 
and  this  may  be  consequent  upon  a  disordered  state  of  the  lungs  themselves,  or 
upon  suspension  of  the  respiratory  movements  through  affections  of  the  Nervous 
centres.  It  is  in  this  mode  that  most  fatal  disorders  of  the  Nervous  System  pro- 
duce death,  except  when  a  sudden  and  violent  impression  occasions  a  cessation  of 
the  heart's  power  ;  thus  in  Apoplexy,  Narcotic  Poisoning,  &c.,  death  results  from 
the  paralyzed  condition  of  the  Medulla  Oblongata ;  whilst  in  Convulsive  diseases, 
the  fatal  result  ensues  upon  a  spasmodic  fixation  of  the  respiratory  muscles. — 
Thirdly,  Somatic  death  may  be  occasioned  by  a  disordered  condition  of  the  Blood 
itself  (§  178),  which  at  the  same  time  weakens  the  power  of  the  Heart,  impairs 
the  activity  of  the  Nervous  system,  and  prevents  the  performance  of  those  changes 
in  the  systemic  capillaries  which  afford  a  powerful  auxiliary  to  the  circulation. 
This  is  Death  by  Necrdemia.* — Fourthly,  Somatic  death  may  result  directly  from 
the  agency  of  Cold,  which  stagnates  all  the  vital  operations  of  the  system. 
Where  the  cooling  is  due  to  the  agency  of  an  extremely  low  external  temperature, 
which  acts  first  upon  the  superficial  parts,  there  is  reason  to  think  that  the  con- 
gestion of  the  internal  vessels  thereby  induced  occasions  a  torpid  condition  of 
the  nervous  centres,  and  that  the  cessation  of  the  Circulation  is  immediately  due 
to  Asphyxia.  But  when  the  cooling  is  gradual,  and  the  loss  of  heat  is  almost 
equally  rapid  throughout,  it  is  obvious  that  the  stagnation  must  be  universal, 
and  that  no  cessation  of  activity  in  any  one  part  is  the  occasion  of  the  torpor  in 
the  functions  of  the  remainder.  It  is  in  this  manner  that  death  results  from 
Starvation  ;  and  not  by  the  weakening  of  the  heart's  action,  as  commonly  sup- 
posed. The  proofs  of  this  have  been  already  stated  (§  658).  And  as  a  general 
rule  we  find,  that  the  more  active  the  changes  which  normally  take  place  in  any 

having  been  thus  induced.     The  state  of  general  debility,  and  the  continued  recumbency, 
both  favor  this  result,  especially  in  persons  advanced  in  life. 

1  See  Dr.  C.  J.  B.  Williams's  "  Principles  of  Medicine,"  3d  Am.  Ed.  p.  484. 


OF   DEATH.  1057 

tissue  during  life,  the  more  speedily  does  its  Molecular  Death  follow  Somatic 
Death,  the  requisite  conditions  of  its  vital  action  being  no  longer  supplied  to  it. 
Thus  we  observe  that,  in  Cold-blooded  animals,  the  supervention  of  Molecular 
upon  Somatic  death  is  much  less  speedy  than  it  is  in  Birds  and  Mammals. 
This  seems  due  to  two  causes.  In  the  first  place,  the  tissues  of  the  former, 
being  at  all  times  possessed  of  a  lower  degree  of  vital  activity  than  those  of  the 
latter,  are  disposed  to  retain  it  for  a  longer  time ;  according  to  the  principle 
already  laid  down.  And,  secondly,  as  the  maintenance  of  a  high  temperature 
is  an  essential  condition  of  the  vital  activity  of  the  tissues  of  warm-blooded  ani- 
mals, the  rapid  cooling  of  the  body  after  Somatic  death  is  calculated  to  extin- 
guish it  speedily ;  and  that  this  cause  has  a  real  operation  is  evinced  by  the 
influence  of  artificial  warmth  in  sustaining  the  vital  properties  of  separate^  parts. 
— The  rapidity  with  which  Molecular  death  follows  the  cessation  of  the  general 
circulation  will  be  influenced  by  a  variety  of  causes ;  but  especially  by  the  degree 
in  which  the  condition  of  the  solids  and  fluids  of  the  body  has  been  impaired 
by  the  mode  of  death.  Thus  in  Necraemia,  Asthenia,  and  Death  by  gradual 
cooling,  Molecular  and  Somatic  death  may  be  said  to  be  simultaneous ;  and  the 
same  appears  to  be  true  of  death  by  sudden  and  violent  impressions  on  the  Nerv- 
ous system  (§  321).  But  in  many  cases  of  death  by  causes  which  operate  by 
producing  a  more  gradual  Syncope  or  Asphyxia,  the  tissues  and  blood  having 
been  previously  in  a  healthy  condition,  Molecular  death  may  be  long  postponed ; 
and  we  cannot  be  quite  certain  that  it  has  supervened  until  signs  of  actual  de- 
composition present  themselves.  When  Molecular  death  takes  place  in  an 
isolated  part,  it  must  result  from  some  condition  peculiar  to  that  part,  and  not 
primarily  affecting  the  body  in  general.  Thus  we  may  have  G-angrene  or  Morti- 
fication of  a  limb  as  adirect  result  of  the  application  of  severe  cold,  or  of  an  agent 
capable  of  producing  chemical  changes  in  its  substance,  or  of  violent  contusions 
occasioning  mechanical  injury ;  or,  again,  from  an  interruption  to  the  current  of 
nutritive  fluid ;  or,  further,  from  some  ill  understood  stagnation  of  the  nutritive 
process,  which  manifests  itself  in  the  spontaneous  death  of  the  tissues  without 
any  assignable  cause,  as  in  some  cases  of  senile  gangrene.  Sometimes  we  are 
enabled  to  trace  this  stagnation  to  a  disordered  condition  of  the  circulating 
fluid ;  as  in  the  gangrene  resulting  from  the  continued  use  of  the  ergot  of  rye 
or  wheat ;  but  we  can  give  no  other  account  of  the  almost  invariable  commence- 
ment of  such  gangrene  in  the  extremities,  than  we  can  of  the  selection  of  lead, 
introduced  into  the  blood,  by  the  extensors  of  the  forearm. — When  Mortification 
or  Molecular  Death  is  once  established  in  any  part,  it  tends  to  spread,  both  to 
contiguous  and  to  distant  portions  of  the  body.  Thus  we  have  continually  to 
witness  the  extension  of  gangrene  of  the  lower  extremities,  resulting  from 
severe  injury  or  from  the  use  of  the  ergot,  from  the  small  part  first  affected, 
until  the  whole  limb  is  involved ;  and  this  extension  is  easily  accounted  for  by 
our  knowledge  of  the  tendency  of  organic  substances,  in  the  act  of  decomposi- 
tion, to  produce  a  similar  change  in  other  organic  substances  subjected  to  the 
influence  of  proximity  to  them.  And  the  propagation  of  the  gangrenous 
tendency  to  remoter  parts  is  obviously  due  to  the  perversion  of  the  qualities 
of  the  Blood,  which  results  from  a  similar  cause.1 

1068.  It  is  quite  certain  that  an  apparent  cessation  of  all  the  vital  functions 
may  take  place,  without  that  entire  loss  of  vitality  which  would  leave  the  organism 
in  the  condition  of  a  dead  body,  liable  to  be  speedily  disintegrated  by  the  opera- 
tion of  chemical  and  physical  agencies  (§  115).  The  state  of  Syncope  is  some- 

1  On  the  proximate  causes  of  Death,  see  especially  the  Art.  "Death,"  by  Dr.  Symonds, 
in  the  "  Cyclop,  of  Anat.  and  Phys.,"  vol.  i. ;  the  first  chapter  of  Prof.  Alison's  "Outlines 
of  Pathology  and  Practice  of  Medicine,"  and  Dr.  C.  J.  B.  Williams's  "  Principles  of  Medi- 
cine," pp.  376,  387,  Am.  ed. 

67 


1058  OF   DEATH. 

times  so  complete  that  the  heart's  action  cannot  be  perceived,  nor  any  respira- 
tory movements  be  observed,  all  consciousness  and  power  of  movement  being  at 
the  same  time  abolished ;  and  yet  recovery  has  spontaneously  taken  place,  which 
could  scarcely  be  the  case,  however,  if  all  vital  action  had  been  suspended.  It  is 
not  a  little  remarkable  that  certain  individuals  have  possessed  the  power  of  volun- 
tarily inducing  this  condition.  The  best  authenticated  case  of  this  kind  is  that 
of  Col.  Townsend,  which  was  described  by  Dr.  George  Cheyne,1  who  was  himself 
the  witness  of  the  fact.  But  statements  have  been  recently  made  respecting 
the  performances  of  certain  Indian  Fakeers,  which  are  far  more  extraordinary; 
it  being  demonstrated,  if  these  assertions  ar6  to  be  credited,3  that  the  Human 
organism  may  not  only  be  voluntarily  reduced  to  a  state  resembling  profound 
collapse,  in  which  there  appear  to  be  a  nearly  complete  suspension  of  all  its  vital 
operations,  but  may  continue  in  that  condition  for  some  days  or  even  weeks — 
until,  in  fact,  means  are  taken  to  produce  resuscitation. — Another  form  of  Ap- 
parent Death,  the  existence  of  which  appears  to  be  well  authenticated,  is  that 
sometimes  designated  as  "Trance"  or  "  Catalepsy,"  in  which  there  is  a  reduction 
of  all  the  Organic  Functions  to  an  extremely  low  ebb,  but  in  which  Conscious- 
ness is  still  preserved,  whilst  the  power  of  voluntary  movement  is  suspended; 
so  that  the  patient,  though  fully  aware  of  all  that  is  being  said  and  done  around, 
is  unable  to  make  the  least  visible  or  audible  sign  of  life.3  It  is  impossible,  in 
the  present  state  of  our  knowledge,  to  give  any  satisfactory  account  of  these 
states ;  but  some  light  appears  to  be  thrown  upon  them  by  certain  phenomena 
of  Artificial  Somnambulism,  "  hypnotic"  or  "  mesmeric"  (§  827) ;  for  in  this 
condition  there  is  sometimes  an  extraordinary  retardation  of  the  respiratory 
movements  and  of  the  pulsations  of  the  heart,  which,  if  carried  further,  would 
produce  a  state  of  complete  collapse ;  and  its  self-induction  is  suspected  by 
Mr.  Braid  to  be  the  secret  of  the  performance  of  the  Indian  Fakeers  just  re- 
ferred to. 

1069.  The  signs  by  which  real  is  certainly  distinguishable  from  apparent  Death 
are  not  numerous,  a  large  proportion  of  those  commonly  relied  on  being  fallacious; 
but  they  are  conclusive. — In  the  first  place,  it  is  to  be  remarked  that  no  reliance 
is  to  be  placed,  for  the  reasons  already  mentioned,  upon  the  apparent  cessation  of 
the  heart's  action,  and  of  the  respiratory  movements;  since  the  reduction  of  these 

1  See  his  "Treatise  on  Nervous  Diseases,"  p.  307. 

2  See  a  collection  of  these  cases,  directly  obtained  from  British  officers  who  had  been 
eye-witnesses  of  them  in  India,  by  Mr.  Braid,  in  his  "  Observations  on  Trance,  or  Human 
Hybernation,"  1850. — In  one  of  these,  vouched  for  by  Sir  Claude  M.  Wade,  formerly  poli- 
tical agent  at  the  Court  of  Runjeet  Singh,  the  Fakeer  was  buried  in  an  underground  cell, 
under  strict  guardianship,  for  six  weeks ;  the  body  had  been  twice  dug  up  by  Runjeet  Singh 
during  the  period  of  interment,  and  had  been  found  in  the  same  position  as  when  first 
buried. — In  another  case,  narrated  by  Lieut.  A.  Boileau,  in  his  "  Narrative  of  a  Journey  in 
Rajwarra,  in  1835,"  the  man  had  been  buried  for  ten  days  in  a  grave  lined  with  masonry 
and  covered  with  large  slabs  of  stone,  and  strictly  guarded  ;  and  he  assured  Lieut.  B.  that 
he  was  ready  to  submit  to  an  interment  of  a  twelve  months'  duration,  if  desired.  — In  a 
third  case,  narrated  by  Mr.  Braid,  the  trial  was  made  under  the  direct  superintendence  of 
a  British  Officer,  a  period  of  nine  days  having  been  stipulated  for  on  the  part  of  the  devotee ; 
but  this  was  shortened  to  three  at  the  desire  of  the  Officer,  who  feared  lest  he  should  incur 
blame  if  the  result  was  fatal. — The  appearance  of  the  body  when  first  disinterred  is  de- 
scribed in  all  instances  as  having  been  quite  corpse-like,  and  no  pulsation  could  be  detected 
at  the  heart  or  in  the  arteries  ;  the  means  of  restoration  employed  were  chiefly  warmth 
to  the  vertex  and  friction  to  the  body  and  limbs. — It  may  be  remarked  that  the  possibility 
of  the  protraction  of  such  a  state  (supposing  that  no  deception  vitiates  the  authenticity 
of  the  narratives  referred  to)  can  be  much  better  comprehended  as  occurring  in  India, 
than  as  taking  place  in  this  country ;  since  the  warmth  of  the  tropical  atmosphere  and 
soil  would  prevent  any  serious  loss  of  heat,  such  as  must  soon  occur  in  a  colder  climate 
when  the  processes  whereby  it  is  generated  are  brought  to  a  stand. 

8  Several  such  cases  are  recorded  in  Dr.  H.  Mayors  "Letters  on  the  Truths  contained 
in  Popular  Superstitions,"  and  also  by  Mr.  Braid,  Op.  cit. 


OP   DEATH.  1059 

to  so  low  a  condition  that  they  are  no  longer  distinguishable,  is  by  no  means  in- 
compatible with  the  persistence  of  vitality.  A  surer  test,  however,  is  afforded 
by  the  condition  of  the  Muscular  substance ;  for  this  gradually  loses  its  irrita- 
bility after  real  Death,  so  that  it  can  no  longer  be  excited  to  contraction  by 
electrical  or  any  other  kind  of  stimulation ;  and  the  loss  of  irritability  is  suc- 
ceeded by  the  appearance  of  cadaveric  rigidity  (§  333).  So  long,  then,  as  the 
muscle  retains  its  irritability,  and  remains  free  from  rigidity,  so  long  we  may 
say  with  certainty  that  it  is  not  dead ;  and  the  persistence  of  its  vitality  for  an 
unusual  period  affords  a  presumption  in  favor  of  the  continuance  of  some  de- 
gree of  vital  action  in  the  body  generally ;  whilst,  on  the  other  hand,  the  en- 
tire loss  of  irritability,  and  the  supervention  of  rigidity,  afford  conclusive  evi- 
dence that  Death  has  occurred.  The  most  satisfactory  proof,  however,  is  given 
by  the  occurrence  of  Putrefaction  ;  this  usually  first  manifests  itself  in  the  blue- 
green  coloration  of  the  cutaneous  surface,  especially  the  abdominal ;  but  it  speedily 
becomes  apparent  in  other  parts,  its  rate  being  usually  in  some  degree  of  accord- 
ance with  the  external  temperature,  though  also  much  influenced  by  the  previous 
condition  of  the  solids  and  fluids  of  the  body,  these  having  been  sometimes  left 
by  diseased  actions  in  a  state  that  renders  them  peculiarly  prone  to  disintegra- 
tion (§  418). 

1070.  With  the  final  restoration  of  the  components  of  the  Human  Organism 
to  the  Inorganic  Universe,  in  those  very  forms,  or  nearly  so,  in  which  they 
were  first  withdrawn  from  it,  the  Corporeal  Life  of  Man,  of  which  it  has  been 
the  object  of  the  foregoing  Treatise  to  sketch  the  leading  features,  comes  to  a 
final  close ;  but  the  Death  of  this  Body  is  but  the  commencement  of  a  new  Life 
of  the  Soul,  in  which  (as  the  religious  physiologist  delights  to  believe)  all  that 
is  pure  and  noble  in  Man's  nature  will  be  refined,  elevated,  and  progressively 
advanced  towards  perfection,  whilst  all  that  is  carnal,  selfish,  and  degrading, 
will  be  eliminated  by  the  purifying  processes  to  which  each  individual  must  be 
subjected  before  Sin  can  be  entirely  subjugated,  and  Death  can  be  completely 
"  swallowed  up  of  Victory." 


INDEX  OF  AUTHORS. 


A. 


ABERCROMBIE,  Dr.,  on  dreaming,  802  note, 
803  note. 

Addison,  Mr.,  on  fibrillation  of  liquor  san- 
guinis,  138;  on  colorless  corpuscles,  163, 
205,  206  note. 

Agassiz,  Prof.,  on  psychical  conformity  of 
human  races,  1040  note. 

Alcock,  Dr.,  on  nerves  of  taste,  687. 

Alison,  Prof.,  on  buffy  coat,  199;  on  muscu- 
lar irritability,  326;  on  asphyxia,  referred 
to,  537  note  ;  on  jaundice  from  suppression 
of  hepatic  excretion,  592  ;  on  guiding  sen- 
sations, 722 ;  on  rapidity  of  muscular 
actions,  919;  on  Death,  referred  to,  1057 
note. 

Allen  and  Pepys,  their  experiments  on  respi- 
ration, 524. 

Ancell,  Mr.,  on  red  corpuscles  of  the  blood, 
referred  to,  158  note;  on  coagulation  of  the 
blood,  195  note. 

Andral,  M.,  on  temperature  in  disease,  618  ; 
on  pathology  of  Corpora  Striata  and  Tha- 
lami  Optici,  710;  on  pathology  of  Cere- 
bellum, 734. 

Andral  and  Gavarret,  MM.,  on  composition 
of  blood  in  health,  171  ;  on  composition  of 
blood  in  disease,  184-189  ;  on  buffy  coat, 
200;  on  expiration  of  carbonic  acid,  526, 
527. 

Arnott,  Dr.,  on  the  venous  circulation,  499  ; 
on  stammering,  940. 

Atkinson,  Mr.  H.  G.,  on  materialism,  771 
note. 

Ascherson,  M.,  on  uses  of  fat,  73. 


B. 


Babington,  Dr.,  on  mucus,  233. 

Baillarger,  M.,  on  gray  matter  of  Cerebrum, 

742. 
Bain,  Mr.  Alex.,  on  laws  of  Association,  780 

note. 

Ballou,  Dr.,  on  suspended  lactation,  1021. 
Baly,   Dr.,   on    glandulae   solitariae,   435  ;    on 

mechanical    excitement    of    olfactive    and 

gustative  sensations,  853,  864  ;    on  Corpus 

Luteum,  966. 

Barker,  Dr.,  his  case  of  early  viability,  984. 
Barlow,  Mr.  F.,  on   spontaneous  movements 

after  death  from  Cholera,  327. 

Rev.  J.,  on  self-control,  809,  810  note. 

68 


Barral,  M.,  on  amount  of  carbon  excreted, 
530;  on  excretion  of  nitrogen,  532;  on 
excretion  of  hydrogen,  533;  oti  statistics  of 
excretion,  576,  577. 

Barruel,  on  odorous  principles  of  blood,  173. 

Barry,  Dr.  Martin,  on  ovisac,  958,  959;  on 
changes  in  germinal  vesicle,  969. 

Baxter,  Mr.,  on  disturbance  of  electric  equi- 
librium in  secretion,  633. 

Beau,  M.,  on  growth  of  nail,  250. 

Beau  and  Maissiat,  MM.,  on  mechanism  of 
respiration,  521  note. 

Beaumont,  Dr.,  on  sense  of  satiety,  384;  on 
movements  of  stomach,  405,  406.;  on  se- 
cretion of  gastric  juice,  420:  on  disordered 
states  of  the  stomach,  421,  422  ;  on  gastric 
digestion,  424-426. 

Beck,  Dr.,  on  superfcetation,  985. 

Beclard,  M.,  on  blood  ofmesenteric  vein,  182; 
on  blood  of  splenic  vein,  183. 

Becquerel,  M.,  on  development  of  electricity 
by  capillary  action,  117. 

Becquerel  and  Breschet,  MM.,  on  develop- 
ment of  heat  by  muscular  contraction,  329  ; 
on  cutaneous  asphyxia,  625. 

Becquerel  and  Rodier,  MM.,  on  composition 
of  blood  in  health,  171,  172,  175,  176;  on 
effect  of  loss  of  blood,  178  ;  on  composition 
of  blood  in  disease,  184-190;  on  increase 
of  cholesterin  in  blood  of  old  persons,  213. 

Belfield-Lefevre,  M.,  on  tactile  sensibility, 
859  note. 

Bell,  Sir  C.,  on  the  hand,  41  ;  on  paralysis  of 
respiratory  muscles,  515  ;  on  distinct  func- 
tions of  anterior  and  posterior  roots  of  spinal 
nerves,  651,  847  note ;  on  cephalic  nerves, 
654;  on  columns  of  Spinal  Cord,  668;  on 
decussation  of  posterior  pyramids,  680  ;  on 
motor  and  sensory  tracts  of  Medulla  Ob- 
longata,  681-682;  on  fifth  pair,  683;  on 
spinal  accessory,  691  ;  on  guiding  sensa- 
tions, 722  ;  on  partial  paralysis,  764. 

Bell,  Mr.  T.,  on  secretion  of  serpent-poison 
after  death,  941 ;  on  Australian  Dingo, 
1037  note. 

Bellingeri,  on  columns  of  Spinal  Cord,  670. 

Bement,  Mr.,  his  cases  of  protracted  gesta- 
tion, 983. 

Bennett,  ProfT,  on  uses  of  fat,  74  ;  on  cyto- 
genesis,  128  ;  on  leucocythsemia,  189  ;  on 
colorless  corpuscles,  205;  on  epithelium- 
cells  of  intestinal  villi,  441  ;  on  production 
of  blood-corpuscles  in  ductless  glands,  462  ; 
on  aggregations  of  disintegrating  blood- 


1062 


INDEX   OP   AUTHORS. 


corpuscles,  464;  on  cells  of  absorbent 
glands,  451  ;  his  cases  of  production  of 
sensations  by  ideas,  857. 

Bensch,  on  milk  of  carnivora,  114. 

Berger  and  Delaroche,  MM.,  their  experi- 
ments on  endurance  of  heat,  620,  621. 

Bernard,  M.  Claude,  on  production  of  fat  in 
the  liver,  71 ;  on  passage  of  cane-sugar 
into  the  urine,  75;  on  presence  of  sugar  in 
blood,  76;  on  production  of  sugar  by  liver, 
76-78;  on  blood  of  hepatic  vein,  183  ; 
on  state  of  gastric  follicles  in  intervals  be- 
tween digestion,  39fi  ;  on  salivary  secretion, 
413;  on  composition  of  gastric  juice,  418  ; 
on  secretion  of  gastric  juice,  420  ;  influence 
of  nervous  system  on,  422;  on  gastric 
digestion,  427  ;  on  pancreatic  fluid,  429  ; 
on  influence  of  bile  on  digestion,  430,  431  ; 
on  intestinal  digestion,  432  ;  on  reflux  of 
blood  to  the  kidneys,  442  note  ;  on  assimi- 
lating power  of  liver,  450,  594  ;  on  in- 
fluence of  lesion  of  Sympathetic  on  animal 
heat,  627  ;  on  motor  roots  of  pneumogastric, 
690;  on  spinal  accessory,  691 ;  on  chorda 
tympani,  718. 

Berzelius,  on  lactic  acid,  79  ;  on  coloring  mat- 
ter of  bile,  96,  97;  on  fluorine,  304;  his 
analysis  of  muscle,  311. 

Bibra,  Von,  on  phosphate  of  lime,  102;  on 
carbonate  of  lime,  103  ;  on  composition  of 
bone,  271,  272  ;  on  composition  of  teeth, 
286. 

Bidder,  on  Sympathetic  nerve-fibres,  338  note; 
on  amount  of  lymph  and  chyle,  454;  on 
structure  of  kidney,  referred  to,  595  note. 

Bidder  and  Schmidt,  on  quantity  of  bile  se- 
creted, 431. 

Bird,  Dr.  Golding,  on  lateritious  sediments, 
85;  on  efflorescence  of  uric  acid,  85;  on 
hippuric  acid,  88  ;  on  inosic  acid,  90;  on 
purpurine,  92  ;  on  xanthine,  93  ;  on  cys- 
tine,  93,  94  ;  on  phosphates  in  urine,  356  ; 
on  coloring  matters  of  urine,  604  note;  on 
oxalates  in  urine,  607;  on  base  of  uric  acid 
deposits,  608  note;  on  action  of  diuretics, 
60S. 

Birkett,  Mr.,  on  anatomy  of  breast,  1019. 

Bischof,  Prof.,  on  excretion  of  urea,  602. 

Bischoff,  Prof.,  on  transfusion  of  blood,  202  ; 
on  excretion  of  carbonic  acid,  529  ;  on  evo- 
lution of  ovum,  958  ;  on  formation  of  cho- 
rion,  971,  972;  on  embryonic  development 
of  Mammalia,  987  note. 

Bishop,  Mr.,  on  physiology  of  Voice,  932-935 ; 
on  stammering,  940  note. 

Bizot,  M.,  on  thickness  of  heart's  parietes, 
475. 

Blagden,  Dr.,  on  endurance  of  heat,  621. 

Blake,  Prof.,  his  estimate  of  amount  of  blood, 
156  ;  on  the  rate  of  circulation,  479. 

Blane,  Sir  G.,  on  reflex  action,  672. 

Blondlot,  M.,  on  secretion  of  gastric  juice, 
420  ;  on  gastric  digestion,  427  ;  on  action 
of  bile  in  digestion,  431  ;  on  quantity  of 
bile  secreted,  431  ;  on  acid  of  caecum,  433. 

Blumenbach,  Prof.,  on  Races  of  Mankind, 
1042. 

Bb'ckmann,  on  comparative  composition  of 
muscle  and  blood,  311. 

Boileau,  Lieut.,  his  case  of  Trance,  1058  note. 

Boileau-Castelnau,  M.,  on  Maison  Centrale  of 
Nismes,  396. 


Bois-Reymond,  M.  Du,  on  electric  disturb- 
ance by  organic  processes,  615  note;  by 
muscular  contraction,  329,  636-637;  on 
muscular  current,  634-636 ;  on  nervous 
current,  637-640. 

Bouchardat  and  Sandras,  MM.,  on  blood  of 
mesenteric  veins,  182. 

Bouillaud,  M.,  his  experiments  on  Cerebel- 
lum, 733. 

Bourdon,  M.,  on  respiratory  movements,  516 
note. 

Boussingault,  M.,  on  production  of  fat  in  the 
body,  71,  72  note;  on  decomposition  of 
urea,  81  ;  on  influence  of  salt,  106;  on  ex- 
halation of  nitrogen,  532. 

Boutigny,  M.  de,  on  spherical  state  of  vapor, 
620  note. 

Boyd,  Dr.  S.,  on  structure  of  mucous  mem- 
brane of  stomach,  4] 6  note. 

Bowman,  Mr.,  on  primary  membrane,  139; 
on  structure  of  cornea,  263  ;  on  crystalline 
lens,  265 ;  on  vitreous  humor,  266  ;  on 
structure  of  muscle,  304,  305  ;  on  contrac- 
tion of  muscle,  307,  308  ;  on  Pacinian  cor- 
puscles, 342  ;  on  fatty  liver,  587  ;  on  struc- 
ture of  kidney,  595-598  ;  on  functions  of 
Malpighian  bodies  of  kidney,  599  ;  on  struc- 
ture of  retina,  879 ;  on  peculiar  form  of 
double  vision,  914  note  (see  Todd  and  Bow- 
man). 

Brachet,  M.,  on  sense  of  hunger,  391 ;  on 
movements  of  stomach,  407. 

Braid,  Mr.,  on  Hypnotism,  794,  801,  802,  827- 
829  ;  on  influence  of  attention  on  organic 
functions,  947,  948;  his  cases  of  Trance, 
1058. 

Brewster,  Sir  D.,  on  crystalline  lens,  265  ;  on 
natural  magic,  794  note;  on  the  Stereo- 
scope, 885,  886  note. 

Brinton,  Dr.,  on  serous  membranes,  232. 

Brittan,  Dr.,  his  observations  on  cholera  at 
Bridgewater,  388  note. 

Brodie,  Sir  B.,  on  influence  of  pneumogastric 
on  secretions  of  stomach,  423;  on  depend- 
ence of  animal  heat  upon  nervous  system, 
626,  627  ;  on  morbid  sensations,  854. 

Brown-Sequard,  M.,  on  spontaneous  rhythmi- 
cal contractions  of  muscles,  319  note;  effects 
of  paralysis  on  irritability  and  cadaveric 
rigidity  of  muscles,  321  note;  on  restora- 
tion of  irritability  by  arterial  blood,  323; 
on  influence  of  electricity  on  duration  of 
muscular  irritability,  333  ;  on  regeneration 
of  nervous  tissue,  347,  348  ;  on  hypertrophy 
of  suprarenal  capsules,  following  injury  of 
spinal  cord,  459  note;  disturbance  of  tem- 
perature produced  by  injuries  of  nervous 
system,  627  ;  effects  of  section  of  spinal 
cord,  670;  effects  of  removal  of  medulla 
oblongata,  676 ;  phenomena  produced  by 
injuries  of  nervous  system,  711. 

Briicke,  on  termination  of  Nerves  in  muscles, 
312  note  ;  on  Peyerian  glands,  435. 

Buchanan,  Prof.,  on  coagulation  of  fibrin,  61  ; 
on  milky  serum,  176. 

Budd,  Dr.  G.,  on  morbid  changes  in  hepatic 
cells,  590  ;  on  abscess  of  liver,  592  ;  on 
jaundice  from  suppression  of  hepatic  excre- 
tion, 592  ;  on  reabsorption  of  bile,  592. 

Budd,  Dr.  W.,  on  symmetrical  diseases,  209; 
on  localization  of  inflammatory  action,  568; 
his  cases  of  paraplegia,  672-674  ;  on  para- 


INDEX   OP  AUTHORS. 


1063 


lysis  of  the  tongue,  693  ;  on  continuance  of 

automatic  movements,  699. 
Budge,  Dr.,  on  columns  of  Spinal  Cord,  670. 
Budge  and  Waller,  Drs.,  on  dilatation  of  pupil 

by  sympathetic,  831. 
Burdach,  on  vicarious  secretion  of  urine,  579, 

580;  on  pathology  of  Cerebellum,  738  ;   on 

influence  of  passion  on  mammary  secretion, 

945  note. 
Burrows,  Dr.  G.,  on  blood-clots,  61  ;  on  the 

intracranial  circulation,  501. 
Bushnell,  Rev.  H.,  on  unconscious  influences, 

792  note. 
Busk,  Mr.  G.,  on  blood  in  Scurvy,  187. 


C. 


Carpenter,  Miss,  on  Juvenile  Reformation, 
833  note. 

Carlyle,  Thomas,  on  Coleridge,  789  note. 

Chatin  and  Bouvier,  MM.,  on  blood  in  scurvy, 
187. 

Chaussier,  M.  on  weight  of  new-born  infants, 
1014. 

Cheselden,  his  case  of  cataract,  882. 

Chevreul,  M.,  on  proportion  of  water  in  the 
body,  100;  on  rhythmical  oscillations,  921 
note. 

Cheyne,  Dr.  G.,  on  case  of  Col.  Townsend, 
1058. 

Chossat,  M.,  his  experiments  on  starvation, 
207,  259,  393,  396,  623  ;  on  diurnal  varia- 
tion of  temperature,  617;  on  dependence 
of  animal  heat  upon  nervous  system,  627. 

Christison,  Dr.,  on  blood  in  albuminuria,  189; 
on  milky  serum,  190. 

Clark,  Mr.  A.,  on  fat  in  feces,  208. 

Clarke,  Mr.  J.  L.,  on  structure  of  Spinal  Cord, 
661-662;  on  roots  of  spinal  accessory,  690. 

Clarke,  Dr.  Joseph,  on  weight  of  new-born 
infants,  1014. 

Coathupe,  Mr.,  on  amount  of  air  respired,  523; 
on  products  of  combustion  of  charcoal,  534., 
535  note. 

Collard  de  Martigny,  M.,  on  respiration  in  ni- 
trogen. 531  ;  on  pulmonary  exhalation,  533. 

Collins,  Dr.,  on  infantile  mortality,  545. 

Combe,  Dr.  A.,  on  digestion,  422 ;  on  influ- 
ence of  passion  on  mammary  secretion, 
945 ;  on  influence  of  mother  on  fetus, 
1011 ;  on  infant  nutrition,  1025. 

Combe,  Mr.  G.,  on  result  of  sexual  intercourse 
in  a  state  of  intoxication,  670. 

Combetti,  his  case  of  destruction  of  Cerebel- 
lum, 734. 

Cooper,  Sir  A.,  his  experiments  on  the  cere- 
bral circulation,  352  ;  on  influence  of  emo- 
tions on  mammary  secretion,  944  ;  on  struc- 
ture of  mammary  gland,  1018-1021. 

Copland,  Dr.,  on  antiphlogistic  regimen,  396, 
397. 

Corfe,  Mr.,  on  water  at  Wolverton,  389  note. 

Cork,  Bishop  of,  his  case  of  lactation  by  male, 
1022  note. 

Corti,  Marquis,  on  cochlear  nerve,  895,  896. 

Coste,  M.,  on  decidua  reflexa,  974. 

Cowan, Dr.,  his  case  of  consensual  movements, 
720  ;  of  apoplexy  of  cerebellum,  734  note. 

Cruveilhier,  M.,  his  case  of  Ectopia  Cordis, 
473. 


Curling,  Mr.,  his  cases  of  hypertrophy  of  the 
fingers,  555  note;  on  atrophy  of  bone,  559. 

Currie,  Dr.,  on  cutaneous  absorption,  446. 

Cuvier,  on  the  hand,  41. 

Czermak,  Prof.,  on  motion  of  particles  within 
cells,  130;  on  structure  and  development 
of  dentine,  288. 


D. 


Dalrymple,  Mr.,  on  vasa  lutea  of  Bird's  egg, 
992  note. 

Dalton,  Dr.,  on  statistics  of  excretion,  576. 

Dalton,  Dr.  J.  C.,  on  difference  in  corpora 
lutea  of  menstruation  and  pregnancy,  966. 

Daniell,  Dr.,  on  adynamic  fevers,  221,  614; 
on  immunity  from  African  fevers,  1039 
note;  on  gradual  death  of  fever  patients, 
1054,  1055  note. 

Davaine,  M.,  on  changes  of  form  of  colorless 
corpuscles,  164. 

Davis,  Dr.  N.  S.,  on  central  lobe  of  cere- 
bellum, 740. 

Davy,  Dr.  J.,  on  venous  hue  of  arterial  blood, 
156;  on  effect  of  loss  of  blood,  178;  on 
non-coagulation  of  blood,  194-196  ;  on  tem- 
perature of  human  body,  616-618. 

Delaroche  and  Berger,  MM.,  their  experi- 
ments on  endurance  of  heat,  620,  621. 

Deleau,  M.,  on  vocal  sounds,  936. 

Dennis,  M.,  on  reduction  of  fibrin  to  state  of 
albumen,  60;  on  composition  of  blood,  175, 
176. 

Desaguliers,  Dr.,  his  examples  of  muscular 
power,  918. 

Devergie,  M.,  on  presence  of  lead  in  muscle, 
214  ;  on  characters  of  embryo  at  different 
periods,  1012,  1013. 

Dieffenbach,  Prof.,  on  transfusion  of  blood, 
202. 

Dill,  Dr.,  his  case  of  absorption  in  diabetes, 
447. 

Dittrich,  on  ciliary  movement,  237. 

Dobson,  Mr.,  his  experiments  on  the  spleen, 
463, 

Dodd,  Mr.,  his  case  of  early  viability,  984. 

Donders,  Prof.,  on  structure  of  nail,  250  ;  on 
absorption  of  solid  particles,  445. 

Donne,  M.,  on  temperature  in  disease,  619 ; 
on  human  milk,  1025. 

Donovan,  Dr.,  on  Irish  starvation,  395;  on 
evolution  of  light,  632. 

Dowler,  Dr.  Bennet,  on  spontaneous  move- 
ments after  death  from  yellow  fever,  327  ; 
on  blood's  movement  after  death,  492;  on 
post-mortem  elevation  of  temperature,  619. 

Doyere,  M.,  on  desiccation  of  Tardigrada, 
55  note. 

Draper,  Prof.,  on  influence  of  Light  on  Plants, 
143;  on  the  capillary  circulation,  496. 

Duges,  M.,  pn  function  of  cerebellum,  734; 
on  function  of  cochlea,  905. 

Dulong,  M.,  on  calorification,  626. 

Dumas,  on  production  of  fat  in  the  body,  71 ; 
on  decomposition  of  urea,  81  ;  on  milk  of 
carnivora,  114. 

Dunglison,  Prof.,  on  gastric  juice,  418  ;  on  cu- 
taneous absorption,  448  ;  on  temperature 
in  disease,  618  ;  heat  of  uterus  in  parturi- 
tion, 623  note;  on  temperature  of  paralyzed 


1064 


INDEX   OF  AUTHORS. 


limbs,  627;  his  cases  of  peculiar  secretion 
of  milk,  1022. 

Dunn,  Mr.,  his  cases  of  apoplexy  of  cerebel- 
lum, 734  n ot e,  739;  of  suspended  cerebral 
action,  838-840  note. 

Dupuy,  M.,  on  injection  of  cerebral  substance 
into  veins,  197. 

Dupuytren,  M.,  on  provisional  callus,  2S2. 

Duval,  M.,  on  pulsations  of  heart  after  death, 
472  note. 

Dzondij  on  deglutition,  401. 


E. 


Earle,  Mr.  H.,  on  temperature  of  paralyzed 
limbs,  627. 

Eberhard,on  absorption  of  solid  particles,  445. 

Ecker,  Prof.,  on  suprarenal  bodies,  458. 

Edwards,  Dr.  W.,  on  respiration  in  hydrogen, 
531;  on  temperature  of  infants,  616  note;  on 
seasonal  variation  of  calorific  power,  618; 
on  influence  of  moist  air,  621  ;  on  inferior 
calorifying  power  of  young  animals,  629,  630. 

Edwards,  Prof.  Milne,  on  infantile  mortality, 

.  630. 

Egerton,  Sir  Philip,  on  effect  of  castration  on 
buck, 212. 

Ehrenberg,  Prof.,  on  limits  of  vision,  879. 

Elliotson,  Dr.,  his  case  of  rapid  respiration, 
513. 

Emerson,  Dr.,  on  infantile  mortality,  630  note. 

Enderlin,  on  ashes  of  blood  and  flesh,  106;  on 
gastric  juice,  418;  on  ash  of  feces,  437. 

Engelhardt,  on  columns  of  Spinal  Cord,  670. 

Erichsen,  Prof.,  on  duration  of  muscular  irri- 
tability, 324;  his  experiments  on  rate  of  ab- 
sorption, 442;  on  Asphyxia,  495,  537,  538 
note. 

Erman,  on  protracted  lactation,  1025. 

Evanson,  Dr.,  his  case  of  abolition  of  sexual 
desire,  739  note. 


F. 


Fenwick,  Mr.,  his  experiments  on  absorption 
by  lacteals,  440. 

Figuier,  M.,  on  analysis  of  the  blood,  172. 

Fletcher,  Dr.,  on  fattening  influence  of  despair, 
943. 

Flourens,  M.,  on  removal  of  Cerebrum,  706, 
753  note;  on  functions  of  Corpora  Quadri- 
gemina,  707,  708;  on  auditory  nerve,  708; 
on  Cerebellum,  732. 

Ford,  Mr.,  his  case  of  absorption  in  ovarian 
dropsy,  447. 

Fordyce  and  Blagden,  Drs.,  their  experiments 
on  endurance  of  heat,  621. 

Fourcault,  Dr.,  on  cutaneous  asphyxia,  613. 

Foville,  M.,  on  function  of  Cerebellum,  734; 
on  pathology  of  Insanity,  754. 

Franklin,  Sir  J.,  his  case  of  lactation  by  male, 
1022  note. 

Fremy,  M.,  on  chemical  composition  of  nerv- 
ous matter,  344. 

Frerichs,  Prof.,  on  metamorphosis  of  uric  acid, 
84;  on  increase  of  urea  after  ingestion  of 
gelatin,  412;  on  composition  of  saliva,  412; 
on  gastric  juice,  417;  on  pancreatic  fluid, 
429-430 ;  on  succus  entericus,  429,  432  ;  on 


meconium,  590,  591;  on  structure  of  kidney, 

referred  to,  595  note  ;  on  uraemia,  600. 
Frey,Prof.,on  bloodvessels  of  Peyerian  glands, 

435;  on  suprarenal  bodies,  458. 
Funke,  on    colorless   corpuscles   in   blood  of 

splenic  vein,  462;  on  blood  of  splenic  vein, 

464-465. 


G. 


GJairdner,  Dr.  W.,  on  production  of  fibrin,  179— 
180. 

Gairdner,  Dr.  W.  T.,  on  formation  of  capilla- 
ries, 301;  on  contractility  of  bronchial  tubes, 
510 ;  on  structure  of  kidney,  referred  to,  595 
note. 

Gall,  on  amative  function  of  Cerebellum,  735-' 
737  ;  on  comparative  development  of  Cere- 
brum, 751. 

Garreau,  M.,  on  production  of  heat  by  Arum, 
621  note. 

Garrod,  Dr.,  on  urea  in  blood,  82";  on  uric  acid 
in  bloodj  86;  on  proximate  cause  of  scurvy, 
109  note;  on  salines  of  blood  in  cholera,  190. 
elatin-Commission,  report  of,  377. 

Gerber,  Prof.,  on  progressive  alteration  of 
chyle,  453. 

Gerlach,  on  ciliary  movement,  237 ;  on  struc- 
ture of  kidney,  referred  to,  595  note,  597. 

Gilchrist,  Dr.,  on  water-dressing,  564. 

Girdwood,  Mr.,  on  periodical  discharge  of  ova, 
961,  968  note. 

Goodfellow,  Dr.,  on  muscular  fibrilla,  306  note. 

Goodsir,  Prof.,  on  primary  membrane,  139,  140; 
on  germinal  spots  of  epithelium,  238;  on 
development  of  teeth,  290-295  ;  on  absorp- 
tion by  intestinal  villi,  441  ;  on  structure  of 
absorbent  glands,  451  ;  on  structure  of  kid- 
ney, referred  to,  595  note;  on  structure  of 
decidua,  972-974  ;  on  villi  of  chorion,  974  ; 
on  formation  of  placenta,  975;  on  cells  of 
milk-follicles,  1020. 

Goodsir,  Mr.  H.  D.  S.,  on  spermatic  cells  of 
Crustacea,  124. 

Gorup-Besanez,  on  guanine,  93 ;  on  silica  in 
hair  and  feathers,  105 ;  on  composition  of 
blood,  170,  172. 

Gosselin,  M.,  on  ciliary  movement,  237. 

Graham,  Prof.,  on  iron  in  blood  of  crab,  204; 
on  gastric  juice,  418  ;  his  law  of  mutual  dif- 
fusion of  gases,  525. 

Grainger,  Mr.,  on  act  of  sucking,  398;  on 
structure  of  Spinal  Cord,  667. 

Granville,  Dr.,  on  heat  of  uterus  in  parturition, 
623. 

Gray,  Mr.  H.,  on  development  of  spleen,  458  ; 
of  suprarenal  bodies,  458,  459;  of  thyroid 
body,  461 ;  of  retina,  879  note;  of  eye  and 
ear,  1010,  1011. 

Green,  Dr.,  on  protracted  lactation,  1025  note. 

Greenhow,  Dr.,  on  treatment  of  burns,  564. 

Gregory,  Dr.,  his  case  of  suggested  dreaming, 
802. 

Gregory,  Prof.,  on  creatine,  89. 

Grove,  Prof.,  on  correlation  of  physical  forces, 
120,  142,  357. 

Gruby  and  Delafond,MM.,on  rhythmical  move- 
ments of  intestinal  villi,  440;  on  epithelium- 
cells  of  villi,  441. 

Guckelberger,  on  oxidation  of  azotized  histo- 
genetic  substances,  88. 


INDEX   OP  AUTHORS. 


1065 


Guillot,  M.,  on  structure  of  liver,  586 ;  on 
amount  of  milk  secreted,  1028  note. 

Gull,  Dr.,  on  uses  of  plexuses  of  nerves,  652  ; 
on  paralysis,  841  note,  847. 

Gulliver,  Mr.,  on  molecular  base  of  chyle,  72; 
on  red  corpuscles  of  blood,  158  note,  159; 
on  colorless  corpuscles,  163,  165;  on  pro- 
duction of  red  corpuscles,  168;  on  coagula- 
tion of  blood,  193-196;  on  buffy  coat,  199, 
200;  on  reunion  of  fractures,  282;  on  rigor 
mortis  of  muscles,  333  ;  on  molecular  base 
of  chyle,  452;  on  gorged  state  of  hepatic 
cells/590. 

Gunther  and  Schbn,  on  degeneration  of  nerve- 
fibres  after  section,  346. 

Guy,  Dr.,  on  the  rate  of  the  pulse,  481,  482; 
on  relative  weights  of  liver  and  lungs,  591. 

Guyot,  M.,  on  treatment  of  wounds  by  hot  air, 
564. 


H. 


Haidlen,  on  composition  of  milk,  1024. 

Hales,  on  the  force  of  heart's  contraction,  479, 
480  ;  on  rate  of  blood's  movement  in  capil- 
laries, 497. 

Hall,  Dr.  C.  Radclyffe,  on  contractility  of  bron- 
chial tubes,  510  ;  on  vital  capacity  of  lungs, 
522 ;  on  decussation  of  posterior  pyramids, 
6SO;  on  ciliary  ganglion,  685  note. 

Hall,  Dr.  J.  C.,  on  protracted  gestation,  982. 

Hall,  Dr.  M.,  on  muscular  irritability,  324,  325; 
on  deglutition,  402;  on  vomiting,  408;  on 
defecation  and  urination,  410 ;  on  action  of 
sphincters,  411;  on  circulation  in  acardiac 
fetus,  493 ;  on  stimulus  to  respiratory  move- 
ment, 514,  515 ;  on  structure  of  Spinal  Cord, 
667;  on  reflex  action  of  spinal  cord,  672, 
695-697,  847  notes  on  muscular  tension, 
700;  on  action  of  cantharides  on  spinal  cord, 
702;  on  emotional  actions,  764;  on  stam- 
mering, 939. 

Haller,  on  quantity  of  blood  in  the  body,  155; 
on  muscular  irritability,  326;  on  respiratory 
pulse,  498  ;  on  vicarious  secretion  of  urine, 
579. 

Hamernjk,  on  sounds  of  heart,  478. 

Hamilton,  Sir  W.,  on  perception,  758  note;  on 
unconscious  action  of  Cerebrum,  791  note. 

Harless,  on  columns  of  Spinal  Cord,  670;  on 
muscular  irritability,  321. 

Harvey,  Dr.  A.lex.,  on  influence  of  fetal  blood 
on  maternal,  970. 

Haygarth,  Dr.,  on  metallic  tractors,  948  note. 

Heller,  on  urine-pigments,  91,  92. 

Helmholtz,  on  chemical  change  induced  by 
muscular  action,  311. 

Henle,  on  nuclear  fibres,  228;  on  bone-lacunae, 
277;  on  Pacinian  corpuscles,  342,343;  on 
development  of  nerve-cells,  345. 

Henry,  Mr.  Mitchell,  his  case  of  deficient  com- 
missures, 746  note. 

Herbst,  on  estimation  of  quantity  of  blood,  155; 
on  amount  of  air  respired,  523. 

Hering,  his  experiments  on  the  circulation,  478, 
479. 

Hertwig,  M.,  on  removal  of  Cerebrum,  706, 
752;  on  functions  of  Corpora  Quadrigemina, 
707;  on  Cerebellum,  732. 

Hewett,  Mr.  Prescott,  on  blood-clots,  61. 

Hevvson,  oared  corpuscles  of  blood,  158,  159; 


his  doctrine  of  lymphatic  absorption,  448, 
449  note;  on  production  of  red  corpuscles 
in  spleen  and  thymus,  462. 

Hofacker,  M.,  on  proportion  of  sexes,  1015. 

Holland,  Dr.  G.  C.,  on  temperature  of  infants, 
616. 

Holland,  Dr.  H.,  on  memory,  782,  783;  on  vo- 
luntary recollection,  784  note;  on  sleep, 
821,  822;  on  mental  physiology,  529;  on 
general  physiology  of  Nervous  System,  re- 
ferred to,  847  note;  on  production  of  sub- 
jective sensations  by  attention,  857;  on  in- 
stinctive choice  of  "food,  &c.,  870  note;  on 
influence  of  expectant  attention  on  involun- 
tary movements,  920,  924  note. 

Home,  Dr.  F.,  on  temperature  in  disease,  618. 

Hooker,  Dr.,  on  relation  between  the  pulse  and 
respiration,  513. 

Homer,  Dr.,  on  axillary  glandulse,  242. 

Houston,  Dr.,  on  circulation  in  acardiac  fetus, 
493. 

Howe,  Dr.,  on  emotional  excitement,  766  note; 
on  idiocy,  817,  970. 

Hubbenet,  on  gastric  juice,  418. 

Huguier,  M.,  oniDuverney's  glands,  962  note. 

Humboldt,  Baron,  his  case  of  lactation  by  male, 
1022  note. 

Hunefeld,  on  action  of  bile,  &c.  on  blood-cor- 
puscles, 162. 

Hunter,  John,  on  coagulation  of  blood,  194, 
196;  on  assumption  of  male  plumage  by  fe- 
male pheasant,  212;  on  muscular  tonicity, 
331,  332;  his  doctrine  of  lymphatic  absorp- 
tion, 448,  449  note;  on  muscular  contractility 
of  arteries,  483,  484;  on  hypertrophy  from 
augmented  supply  of  blood,  555;  on  healing 
processes,  562;  his  case  of  paraplegia,  674, 
675  note;  on  oblique  muscles  of  eye,  913. 

Hunter,  Dr.  W.,  on  Decidua  reflexa,\973. 

Huss,  Dr.,  on  Alcoholismus  chronicus,  390. 

Hutchinson,  Col.,  on  ancon  breed  of  sheep, 
1037  note. 

Hutchinson,  Dr.,  on  elastic  tension  of  lungs, 
510;  on  action  of  intercostal  muscles,  511; 
on  forces  of  inspiration  and  expiration,  512; 
on  number  of  respirations,  513 ;  on  vital  ca- 
pacity of  chest,  521 ;  its  relation  to  height 
and  weight,  521,  523  ;  on  amount  of  air  in- 
spired, 523  ;  on  limit  of  suspension  of  re- 
spiratory movements,  536  note. 

Hutchison,  Dr.,  his  case  of  lost  sense  of  smell, 
869  note;  on  change  of  color  in  negro, 
1030  note. 


J. 


Jackson,  Dr.,  on  correlation  of  physical  forces, 
142  note;  on  vital  force,  146-147;  on  vital 
capacity  of  lungs,  522;  on  gradual  death  in 
adynamic  fevers,  1054,  1055  note. 

Jacubowitsch  on  saliva,  414  note. 

Jeffreys,  Mr.  J.,  on  inspired  air,  521,  523. 

Johnson,  Dr.  G.,  on  structure  of  kidney,  re- 
ferred to,  595  note;  on  oblique  muscles  of 
eye,  913. 

Johnstone,  Dr.,  on  conversation  of  deaf  and 
dumb,  935. 

Jones,  Dr.  Bence,  on  water  in  blood,  177; 
on  phosphates  in  urine,  355,  356,  606, 
607;  on  gravel,  calculus,  and  gout,  385; 
on  action  of  saliva  in  stomach,  414;  on 


1066 


INDEX   OF   AUTHORS. 


gastric  juice,  418;  on  emulsification  by 
bile,  430;  on  interchange  of  gases  in  re- 
spiration, 524;  on  production  of  nitric 
acid  in  the  body,  526,  606;  on  sulphates  in 
urine,  606;  on  acidity  of  urine,  608,  609  ; 
on  alkalescence  of  urine,  608,  609  ;  on  base 
of  uric  acid  deposits,  608  note, 

Jones,  Dr.  Handfield,  on  structure  of  liver, 
587  note  ;  on  biliary  cells,  587  note. 

Jones,  Mr.  Wharton,  on  red  corpuscles  of 
blood,  158,  169;  on  colorless  corpuscles, 
164,  165,  205,  206  ;  on  gradation  of  forms  of 
blood-corpuscles,  169  ;  on  buffy  coat,  199  ; 
on  rhythmical  movements  of  veins  of  bat's 
wing,  455;  on  effects  of  stimuli  on  the 
smaller  arteries,  484 ;  on  retardation  of 
capillary  circulation  by  stream  of  carbonic 
acid,  495. 

Jurin,  Dr.,  on  absorption  of  vapor,  447. 


K. 


Kaster,  on  luminosity  of  perspiration,  633. 

Kellie,  Dr.,  on  the  intracranial  circulation, 
501. 

Kempelen,  on  vowel  sounds,  936. 

Kiernan,Mr.,  on  structure  of  liver,  583-589  ; 
on  secretion  of  bile  from  venous  blood, 
591. 

Kilian,  on  fatty  degeneration  of  uterus  after 
parturition,  553. 

King,  Mr.  T.  W.,  on  tricuspid  valve,  475. 

Kirkes  and  Paget,  on  vital  force,  148;  their 
Handbook  referred  to.  Preface,  436;  on 
passage  of  Cerebro-spinal  fibres  through 
sympathetic  ganglia,  830. 

Kitto,  Dr.,  on  guiding  sensations,  723  ;  his 
cases  of  acute  tactile  sensibility,  862  note. 

Kiwisch,  on  sounds  of  heart,  478. 

Knox,  Dr.,  on  the  diurnal  variation  of  the 
pulse,  482. 

Kblliker,  Prof.,  on  motion  of  particles  within 
cells,  130;  on  contractile  tissue  of  skin, 
242;  on  development  of  cutaneous  glandu- 
lae,  244-246  ;  on  termination  of  nerves  in 
cutaneous  papillae,  246  note ;  on  develop- 
ment of  epidermic  cells,  243;  on  structure 
and  development  of  hair,  252-256  ;  on  fat- 
cells,  257 ;  on  bone  lacuna?,  278 ;  on  for- 
mation of  capillaries,  301  ;  on  formation  of 
absorbents.  302 ;  on  union  of  muscle  and 
tendon,  309  ;  on  fusiform  muscular  fibre 
cells,  309,  310,  317;  on  subdivision  of 
muscular  fibre,  310;  on  absorbents  of  mus- 
cle, 312;  on  termination  of  nerves  in  mus- 
cle, 312,  313  note;  on  structure  of  tubular 
nerve-fibre,  336  ;  on  connection  of  nerve- 
fibres  with  cells,  340;  on  peripheral  termi- 
nations of  nerve-fibres,  341,  342;  on  Pa- 
cinian  corpuscles,  342,  343;  on  develop- 
ment of  nerve-fibres,  347;  on  muscular 
structure  of  intestinal  villi,  440;  on  epithe- 
lium-cells of  intestinal  villi,  441  ;  on  con- 
tractions of  lymphatics,  454  ;  on  structure 
of  spleen,  456-458;  on  functions  of  spleen, 
464-465;  on  structure  of  arterial  walls, 
483 ;  on  structure  of  walls  of  veins,  497  ; 
on  erectile  tissue,  501  ;  on  muscular  fibres 
of  bronchial  tubes,  506  ;  on  air-cells  of 
lungs,  506;  on  structure  of  kidney,  refer- 
red to,  595  note}  on  structure  of  spinal 


cord,  660,  666-667  ;  on  corpora  striata  and 
thalami  optici,  705;  on  tactile  papillae, 
858  ;  on  development  of  spermatozoa,  954  ; 
on  embryonic  development  of  Entozoa, 
987. 

Krahmer,  Prof.,  on  action  of  diuretics,  610. 

Krause,  on  intestinal  glandulae,  240,  434. 

Kronenberg,  Dr.,  on  roots  of  spinal  nerves, 
651. 

Kiiss,  on  epithelium-cells  of  villi,  441. 


L. 


Lacauchie,  M.,  on  contractility  of  intestinal 
villi,  440. 

Laer,  Von,  on  silica  in  hair,  105 ;  on  iron  in 
hair,  109. 

Lafargue,  M.,  on  lesion  of  Thalami  Optici, 
709  ;  on  Corpora  Striata,  709;  on  cerebel- 
lum, 733. 

Lallemand,  M.,  on  morbid  sympathies,  835. 

Landerer,  Dr.,  on  urea  in  sweat,  82,  612. 

Larrey,  Baron,  on  Syro-Arabian  race,  1044. 

Latham,  Dr.,  on  scurvy  at  Milbank,  396. 

Latham,  Dr.  R.  G.,  on  Negro  area,  1031 
note;  on  Indo-Germanic  race,  1043,  1044 j 
on  Syro-Arabian  race,  1044,  1045  ;  on  po- 
pulation of  India,  1045;  on  Kaffre  lan- 
guage, 1049. 

Lassaigne,  on  carbonate  of  lime  in  teeth, 
103. 

Laycock,  Dr.,  on  vicarious  secretion  of  urine, 
579  ;  on  reflex  function  of  brain,  774  note, 
810  note,  847  note;  on  morbid  sympathies, 
835  ;  on  connection  of  gout  and  hysteria, 

Lebert,  M.,  on  development  of  muscular  tis- 
sue, 313,  314. 

Lecanu,  M.,  on  composition  of  blood,  175, 
176;  on  water  of  blood  in  cholera,  190; 
on  fat  in  blood,  190  ;  on  excretion  of  urea, 
602. 

Lee,  Dr.  R.,  on  periodical  discharge  of  ova, 
961. 

Lee,  Mr.  H.,  on  the  effect  of  admixture  of  pus 
with  blood,  198. 

Legallois,  M.,  on  dependence  of  heart's  ac- 
tion on  spinal  cord,  468  note;  on  animal 
heat,  627. 

Lehmann,  Prof.,  his  Physiological  Chemistry 
referred  to,  53;  on  casein,  57;  on  vitellin, 
58  ;  on  fibrin,  59,  60  ;  on  production  of  fat, 
72  note;  on  uses  of  fatty  matters,  73;  on 
absorption  of  sugar,  76  ;  on  lactic  acid,  79, 
80;  on  urea  in  the  blood,  82;  on  uric  acid, 
83;  on  production  of  uric  acid,  86;  on  con- 
stitution of  hippuric  acid,  87  ;  on  constitution 
of  biliary  acids,  94-96;  on  origin  of  bile, 
98;  on  analyses  of  inorganic  components, 
98;  on  phosphate  of  lime,  101  ;  on  carbon- 
ate of  lime,  102;  on  chloride  of  sodium  in 
blood,  105;  in  other  fluids,  106;  on  alkaline 
carbonates,  107;  on  non-existence  of  am- 
monia in  fresh  urine,  109;  on  decomposition 
of  sulphates  in  alimentary  canal,  110;  on 
composition  of  blood,  160,  172,  173;  on 
absorbent  power  of  defibrinated  blood,  161 ; 
on  solution  of  blood-corpuscles,  162;  on 
blood  of  hepatic  vein,  183;  on  alkaline  salts 
of  blood,  190;  on  serous  effusions,  231  ;  on 
saliva,  412,  413;  on  gastric  juice,  418;  on 


INDEX   OF   AUTHORS. 


1067 


intestinal  digestion,  429  ;  on  composition  of 
feces,  437 ;  on  composition  of  urine,  601; 
on  variations  in  proportions  of  components, 
602-605;  on  acid  reaction  of  urine,  607; 
on  base  of  uric- acid  sediments,  608. 

Leibnitz,  on  unconscious  action  of  brain,  791 
note. 

Leidy,  Dr.,  on  fission  of  cartilage-cells,  126; 
on  structure  of  cartilage,  260  ;  on  develop- 
ment of  lacunae,  277-278  note;  on  ossifica- 
tion, 277;  on  structure  of  liver,  581,  585, 
586,  587. 

Lenz,  M.,  on  intestinal  digestion,  429. 

Leteliier,  M.,  on  influence  of  external  tem- 
perature on  production  of  carbonic  acid,  526. 

Letheby,  Dr.,  on  elimination  of  arsenic,  111  ; 
on  elimination  of  narcotic  poisons,  215;  on 
discharge  of  ovules  in  menstruation,  967 
note. 

Leuchs,  on  transforming  powers  of  saliva,  414 
note. 

Leuckardt,  Dr.,  on  Spermatozoa,  955  note. 

Leuret,  M.,  on  comparative  anatomy  of  Cere- 
bellum, 729;  on  comparative  size  of  Cere- 
bellum in  geldings,  &c.,  737-738. 

Lever,  Dr.,  on  connection  of  albuminuria  and 
puerperal  convulsions,  600  note. 

Ley,  Dr.  H.,  his  case  of  disordered  respiration, 
516. 

L'Heritier,  M.,  on  composition  of  nervous 
matter,  343. 

Liebig,  Prof.,  on  action  of  ferments,  54,  387  ; 
on  change  in  albumen  by  boiling,  55;  on 
substance  of  muscle,  56,  59;  on  blood- 
fibrin,  63  ;  on  function  of  blood-corpuscles, 
65  note;  on  gelatin,  67;  on  production  of 
fat,  71  ;  on  production  of  cholesteric  acid, 
74;  on  cerebric  acid,  75;  on  metamorpohsis 
of  uric  acid,  84;  on  solution  of  uric  acid  by 
phosphate  of  soda,  85;  on  hippuric  acid,  87; 
on  creatine,90;  on  inosic  acid,  90;  on  uses 
of  alkalinity  of  blood,  107;  on  relative  pro- 
portions of  alkaline  phosphates  and  carbo- 
nates, 107,  108;  on  proportions  of  soda  and 
potash  in  blood  and  muscle,  109;  on  meta- 
morphoses of  organic  compounds,  114;  on 
calorific  powers  of  different  articles  of  food, 
379;  on  nature  of  fecal  matters,  437,438, 
539  note;  on  purgative  action  of  saline 
solutions,  444  note;  on  amount  of  carbon 
excreted,  530;  on  quantitative  estimation  of 
urea,  602;  on  chemical  theory  of  calorifica- 
tion, 626,  628. 

Lining,  on  absorption  of  vapor,  447. 

Longet,  M.,  on  contractility  of  bronchial  tubes, 
509  ;  on  columns  of  Spinal  Cord,  668,  669  ; 
on  roots  of  pneumogastric,  688 ;  on  remo- 
val of  Cerebrum,  706  ;  on  functions  of  Cor- 
pora Quadrigemina,  707,708;  on  Thalami 
Optici,  709;  on  Corpora  Striata,  710;  on 
Crura  Cerebri,  710;  on  Cerebellum,  732, 
734;  on  division  of  fifth  pair,  947. 

Lonsdale,  Dr..  on  departure  of  odor  of  prus- 
sic  acid,  215. 


M. 


Macartney,  Prof.,  on  the  healing  processes, 
561-563  ;  on  treatment  of  wounds  by  steam, 
564. 

Macgregor,  Mr.,  on  increase  of  expiration  of 
carbonic  acid  in  diseases  of  skin,  527. 


Mackinnon,  Dr.,  on  Tropical  Hygiene,  544. 

Macleod,  Mr.,  on  formation  of  blood-corpus- 
cles, 128. 

M'William,  Dr.,  on  artificial  lactation,  1021. 

Madden,  Dr.  W.  H.,  on  muscular  irritability, 
321;  on  cutaneous  absorption,  446,  447  ;  on 
pulmonary  absorption,  534;  on  tuberculosis, 
573. 

Madden,  Dr.  Henry,  on  the  magnetometer, 

922  note. 

Magendie,  M.,  on  sugar  in  the  blood,  76  note  ; 
on  absorption  of  sugar,  76  ;  on  transudation 
of  blood,  192  ;  on  act  of  vomiting,  407  ;  on 
saliva,  413,  414;  on  roots  of  spinal  nerves, 
651;  on  removal  of  Cerebrum,  706,  707; 
on  falsetto  voice,  933 ;  on  division  of  fifth 
pair,  947. 

Magron,  Dr.  Martin,  on  phenomena  produced 
by  injuries  of  nervous  system,  711. 

Magnus,  on  gases  of  blood,  179. 

Malacorps,  M.,  on  removal  of  Cerebrum,  707. 

Malcolm,  Mr.,  on  diminution  of  excretion  of 
carbonic  acid  in  typhus,  527. 

Marc,  M.,  his  case  ofsuspended  animation,536. 

Marchand,  M.,  on  influence  of  diet  on  blood, 
178. 

Marsh,  Sir  H.,  on  evolution  of  light,  632,  633. 

Marshall,  Mr.,  on  development  of  veins,  996. 

Martineau,  Miss,  on  materialism,  771  note; 
her  case  of  idiocy,  813  note. 

Matteucci,  Prof.,  on  endosmosis  of  fatty  mat- 
ters, 258;  on  development  of  electricity  by 
muscular  contraction,  329,  330, 637  note  ;  on 
influence  of  electric  currents  upon  nervous 
excitability,  351  ;  on  relation  of  electricity 
and  nerve-force,  357  ;  on  disturbance  of  elec- 
tric equilibrium  in  organic  processes,  683; 
on  muscular  current,  636,  637. 

Mayer,  Dr.,  on  organic  force,  146  note;  on 
vicarious  secretion  of  urine,  579. 

Mayhew,  Mr.  Henry,  on  nomadic  races,  1035, 
1050. 

Mayo,  Mr.  H.,  on  glosso-pharyngeal  nerve, 
403  ;  on  guiding  sensations,  724;  on  rhyth- 
mical oscillations,  921  ;  on  the  divining  rod, 

923  note  ;  on  falsetto  voice,  933. 
Melsens,  on  non-existence  of  copper  in  blood, 

111. 

Mendelssohn,  on  mechanism  of  respiration, 
521  note. 

Mensonides,  on  absorption  of  solid  particles, 
445. 

Mialhe,  M.,  on  albuminose,  182  ;  on  salivary 
secretion,  414  note. 

Mill,  Mr.  James,  on  ideation,  757  note;  on 
emotions,  762  note. 

Mr.  John  S.,  on  causation,  35  ;  on  explana- 
tion of  phenomena,  471  note;  on  uncon- 
scious action  of  cerebrum,  191  note. 

Millon,  M.,  on  urea  in  eye,  82;  on  silica  in 
blood,  105;  on  copper  in  blood,  111  note. 

Mitchell,  Dr.,  on  heart  of  sturgeon,  468  ;  on 
continuance  of  heart's  action  in  vacua,  469  ; 
on  mutual  diffusion  of  gases,  524. 

Moleschott,  on  size  of  pulmonary  air-cells, 
507  note. 

Montgomery,  Dr.,  on  corpus  luteum,  964  ;  on 
placental  bruit,  978 ;  on  duration  of  preg- 
nancy, 9»3  note;  on  influence  of  mother  on 
fetus,  1012  note. 

Moore,  Mr.,  on  casein  of  human  milk,  1023, 
1024. 


1068 


INDEX   OP   AUTHORS. 


Moreau,  M.,  on  Haschisch,  772,  803-804. 

Morell,  Mr.,  on  perception,  758. 

Morgan,  Mr.,  on  mammary  foetus  of  kangaroo, 
398. 

Miller,  Prof.,  on  presence  of  lead  in  muscle, 
214  note. 

Mulder,  Prof.,  on  protein,  53  note  ;  his  oxides 
of  protein,  60. 

Miiller,  Prof.,  on  envelopes  of  blood-corpus- 
cles, 162;  on  coagulation  of  the  blood,  193; 
on  termination  of  nerves  in  muscle,  312  note  ; 
on  muscular  irritability,  319  ;  on  absorption 
by  cutaneous  lymphatics,  448 ;  on  erectile 
tissue,  501 ;  on  respiration  in  hydrogen,  531  ; 
on  mots  of  spinal  nerves,  651 ;  on  laws  of 
nervous  transmission,  652-654 ;  on  motor 
roots  ofpneumogastric.  6b8;  on  Cerebellum, 
733;  on  erect  vision,  883  ;  on  complemen- 
tary colors,  891-892  ;  on  acoustic  princi- 
ples of  hearing,  897-901  ;  on  length  of  vocal 
cords,  919  ;  his  researches  on  voice,  931-934; 
on  stammering,  940;  on  venous  system  of 
fishes,  996. 

Murphy,  Prof.,  his  cases  of  protracted  gesta- 
tion, 983  note. 


N. 


Nairne,  Dr.,  his  case  of  softening  of  Spinal 
cord,  669  note. 

Nasse,  Prof.,  on  specific  gravity  of  blood,  156  ; 
on  buffy  coat,  199;  on  colorless  corpuscles, 
205;  on  development  of  heat  in  muscular 
contraction,  329  note  ;  on  degeneration  of 
nerves  after  section,  346 ;  on  composition 
of  chyle,  452. 

Neill,  Dr.,  on  structure  of  mucous  membrane 
of  stomach,  416. 

Nelson,  Dr.,  on  spermatic  cells  of  nematoid 
Entozoa,  J24. 

Newport,  Mr.,  on  relations  of  Vital  and  Phy- 
sical forces,  146  note  ;  on  diffluence  of  sper- 
matozoa, 192  note  ;  on  blood  corpuscles  of 
insects,  205;  on  nervous  ganglia  of  Articu- 
lata,  340;  on  increase  of  carbonic  acid  ex- 
creted, by  exercise,  528  ;  on  production  of 
heat  by  bees,  622  ;  on  plexuses  of  wing- 
nerves,  652  ;  on  fertilizing  power  of  sperma- 
tozoa, 955  note,  968,  969  ;  on  changes  in 
germinal  vesicle,  969 ;  on  embryonic  de- 
velopment of  Batrachia,  987. 

Noble,  Mr.,  his  cases  of  paralysis  of  fifth  pair, 
688  ;  his  case  of  paralysis  of  volition,  835 
note. 

Norris,  Mr.,  on  Syro-Arabian  race,  1044;  on 
population  of  India,  1046  ;  on  Hottentot 
language,  1049  note ;  on  Australian  lan- 
guage, 1053. 

Nysten,  on  duration  of  muscular  irritability, 
320 ;  on  diminution  of  carbonic  acid  ex- 
creted, in  diseases  of  respiratory  organs, 
528;  on  vicarious  secretion  of  urine,  579. 


O. 


Oesterlen,  on  absorption  of  solid  particles,  445. 
Oldham,  Dr.,  on  period  of    conception,  968 

note. 
011ivier,M.,  on  pathology  of  Spinal  Cord,  738. 


Oppenheim,  Dr.,  his  case  of  imitative  suicide, 
809  note. 

Orfila,  on  arsenic  in  human  tissues,  111. 

Outrepont,  Dr.,  his  case  of  early  viability,  984. 

Owen,  Prof.,  on  Troglodytes  gorilla,  46;  on 
contraction  of  muscular  fibre,  306  ;  on 
sperm-cell  and  germ-cell,  949  ;  on  typical 
vertebra,  1006,  1007  ;  on  cranial  vertebrae, 
693,  1007,  1008  ;  on  Mauchamp  breed  of 
sheep,  1037  note. 


P. 


Pacini,  on  Pacinian  corpuscles,  342. 

Paget,  Mr.,  on  inflammatory  effusions,  63;  on 
latty  degeneration,  71,  553,  560  ;  on  stellate 
nuclei  of  cartilage-cells,  123  ;  on  large  com- 
pound cells  of  granulations,  1027  note ;  on 
reproduction  of  tendon,  13S;  on  cancerous 
diathesis,  141;  on  red  corpuscles  of  blood, 
158;  on  development  of  blood-corpuscles, 
166-168;  on  fibrin  of  abnormal  blood,  185; 
on  organization  of  blood-clot,  194;  on  re- 
tarded coagulation  of  blood,  195;  on  color- 
less corpuscles,  205,  206  ;  on  symmetrical 
diseases,  209  ;  on  complementary  nutrition, 
210-212;  on  reproduction  of  fibrous  tissues, 
227-229 ;  on  abnormal  osseous  structure, 
280;  on  union  of  fractured  bones,  282  ;  on 
formation  of  capillaries,  301-302;  on  con- 
centric hypertrophy  of  heart,  334  ;  on  propa- 
gation of  contractile  movements  of  heart, 
468  ;  on  complete  contraction  of  heart,  478  ; 
on  effects  of  mechanical  irritation  on  smaller 
arteries,  484;  on  capillary  circulation,  495; 
on  formative  power  of  individual  parts,  551, 
552,  554  ;  on  fatty  degeneration  of  lymph, 
554  ;  on  tumors,  557  ;  on  reparative  power, 
560  ;  on  healing  processes,  562-566  ;  on 
inflammation,  567-572 ;  on  localization  of 
inflammatory  action,  567  ;  on  heat  of  inflam- 
mation, 569  ;  on  lymph-products  of  inflam- 
mation, 570,  571  ;  on  tuberculosis,  573  ;  on 
fatty  liver,  590  ;  his  case  of  deficient  com- 
missures, 746  note  ;  on  influence  of  nervous 
system  on  nutrition,  946. 

Paget,  Dr.,  on  morbid  rhythmical  movements, 
734  note. 

Panum,  Dr.,  on  Casein,  56,  57 ;  on  sanitary 
condition  of  Faroe  islands,  388. 

Parent-Duchatelet,  M.,  on  inhalation  of  sul- 
phuretted hydrogen,  534. 

Parker,  Mr.  Langston,  on  mercurial  inhalation, 
535  note. 

Parkes,  Dr.,  on  blood  in  cholera,  187. 

Peddie,  Dr.,  on  mammary  secretion,  1102. 

Percy,  Baron,  on  siege  of  Landau,  1011. 

Percy,  Dr.,  on  passage  of  cane-sugar  into  the 
urine,  75;  on  composition  offeces,  436;  his 
experiments  on  absorption  of  alcohol,  443. 

Pereira,  Dr.,  on  Food  and  Diet  referred  to,  385 
note,  389  note. 

Petrequin,  M.,  on  falsetto  voice,  934. 

Pettenkofer's  test  for  bile,  95,  98. 

Philip,  Dr.,  Wilson,  on  independent  action  of 
heart,  468  note  ;  on  capillary  circulation, 
496  ;  on  maintenance  of  animal  heat  by  arti- 
ficial respiration,  626. 

Pinel-Grandchamp,  M.,  on  function  of  Cere- 
bellum, 734. 

Playfair,  Dr.  L.,  on  comparative  composition 


INDEX   OF  AUTHORS. 


1069 


of  muscle  and  blood,  311;  on  composition 
of  milk,  1025. 

Poggiale  on  composition  of  blood,  175. 

Poisseuille,  M.,  his  experiments  on  the  rate  of 
circulation,  478;  on  force  of  heart's  con- 
traction, 479  ;  on  haemadynamometer,  479- 
480;  on  muscular  contractility  of  arteries, 
484 ;  on  lateral  pressure  of  blood  within 
arteries,  490. 

Polli,  on  effect  of  loss  of  blood,  178;  on  co- 
agulation of  blood,  194-196. 

Prevost  and  Dumas,  MM.,  on  fertilizing  power 
of  Spermatozoa,  955  note. 

Prichard,  Dr.,  on  Varieties  of  Man,  1030  note; 
on  typical  forms  of  skull,  1032  ;  on  changes 
in  domesticated  animals,  1038  note;  on 
psychical  conformity  of  human  races,  1040; 
on  Celtic  languages,  1043;  on  somatic  death, 
1054. 

Prochaska,  on  reflex  action,  672;  on  the  gen- 
eral Physiology  of  the  Nervous  System, 
referred  to,  847  note. 

Prout,  Dr.,  his  classification  of  alimentary 
substances,  375,  377  note  ;  on  conversion  of 
starch  into  albumen,  444,  445  ;  on  secondary 
digestion,  449  ;  on  excretion  of  carbonic 
acid,  528;  on  quantity  of  urine,  601 ;  on  its 
specific  gravity,  601. 

Purkinje,  optical  experiment  of,  893. 


Q. 

Quain,  Dr.  R.,  on  fatty  degeneration,  72. 

Quekett,  Mr.,  on  elastic  tissue  of  Giraffe,  225 
note  ;  on  lacuna?  of  bone,  268  ;  on  muscular 
fibrilla,  305,  306  note ;  on  elastic  tissue  in 
feces,  436  note. 

Queteiet,  M.,  on  influence  of  seasons  on  mor- 
tality, 630 ;  on  length  and  weight  of  new- 
born infants,  1013, 1014;  on  viability  of  male 
and  female,  1015,  1016  ;  on  relative  heights 
and  weights  of  male  and  female  at  different 
ages,  1016,  1017. 


R. 


Raciborski,M.,  on  periodical  discharge  of  ova, 
961. 

Rathke,  on  development  of  venous  system, 
995. 

Rawitz,  Dr.,  on  components  of  feces,  436. 

Redfern,  Dr.,  on  structure  of  cartilage,  260, 
262. 

Redtenbacher,  on  sulphur  in  taurine,  96. 

Rees,  Dr.  G.  O.,  on  urea  in  milk  and  liquor 
amnii,  82;  on  fluorine,  104  note;  on  red 
corpuscles  of  blood,  158;  on  phosphorized 
fats  of  blood,  178  ;  on  composition  of  chyle 
and  lymph,  451,  452;  on  composition  of 
milk,  1026. 

Regnault  and  Reiset,  MM.,  on  production  of 
carbonic  acid  in  respiration,  525  ;  on  absorp- 
tion and  exhalation  of  nitrogen,  531. 

Reich,  on  phosphorized  fats  of  blood,  179. 

Reichenbach,  Baron,  on  odyle,  829. 

Reid,  Dr.  John,  on  muscular  irritability,  316, 
324,  325;  on  sense  of  hunger,  391;  on 
nerves  of  deglutition,  402,  403,  404;  on 
movements  of  stomach,  407  ;  on  restoration 
of  digestion  after  section  of  pneumogastrics, 


423;  on  influence  of  nerves  on  secretion, 
424;  on  heart's  action  in  vacuo,  469;  on 
excitement  of  heart's  contractions  through 
nerves,  469  ;  on  re-excitement  of  heart's 
action  by  relief  of  distension,  476;  on  re- 
tardation of  systematic  circulation  in  as- 
phyxia, 495  ;  on  function  of  pneumogastric 
in  respiration,  514;  on  laryngeal  nerves, 
517,  518;  on  results  of  section  of  pneumo- 
gastrics, 519-521  ;  on  asphyxia,  referred  to, 
537  ;  his  case  of  hypertrophy  of  a  limb,  555 
note;  on  functions  of  glosso-pharyngeal, 
687,  688  ;  on  nerves  of  taste,  687,  688  ;  on 
motor  roots  of  pneumogastric,  688 ;  on  spi- 
nal accessory,  691 ;  on  structure  and  connec- 
tions of  placenta,  976;  on  Eustachian  valve, 
997,  998. 

Reil,  on  nerves  of  internal  senses,  728,  756. 

Reinhardt,  on  Graafian  vesicle,  958  note;  on 
colostric  corpuscles,  1023. 

Remak,  on  organic  nerve-fibres,  338  note. 

Report  of  Board  of  Health  on  Cholera,  388, 
539-543. 

Report  of  Registrar-General,  on  influence  of 
cold  on  mortality,  631. 

Reports  of  Committees  on  Sounds  of  Heart, 
477. 

Retzius,  Dr.,  on  fat  in  urine  after  parturition, 
980  note. 

Retzius,  Prof.,  on  structure  of  liver,  587  ;  on 
variations  in  position  of  cerebellum,  736  ; 
on  development  of  cerebrum,  1010  note. 

Richardson,  Sir  J.,  on  arctic  diet,  78  note, 
381  note;  on  endurance  of  cold,  620. 

Ritchie,  Dr.,  on  evolution  of  ova,  959,  961. 

Roberton,  Mr.,  on  menstruation,  959,  960. 

Roberts,  Mr.,  his  apparatus  for  reading  card 
in  rapid  motion,  891  note. 

Robin,  on  axillary  glandule,  242  ;  on  decidua, 
974  note. 

Robinson,  Mr.,  on  transudation  from  blood, 
231  ;  on  effusion  of  fibrin,  570. 

Rochoux,  M.,  on  number  of  pulmonary  air- 
cells,  507. 

Roger,  M.,  on  temperature  of  infants,  616- 
618. 

Rogers,  Mr.,  his  Report  on  Cholera  in  Madras 
Army,  541. 

Rokitansky,  Prof.,  on  fatty  degeneration,  71. 

Rolando,  M.,  his  experiments  on  cerebellum, 
732. 

Ronalds,  Prof.,  on  sulphur  and  phosphorus  in 
urine,  92,  604. 

Rose,  Prof.,  his  analyses  of  inorganic  compo- 
nents, 99. 

Rosenthal,  on  Medulla  Oblongata,  677. 

Rossignol,  M.,  on  pulmonary  structure,  508. 

Rostan,  M.,  on  starvation,  395. 

Routh,  Dr.,  on  puerperal  fever  of  Vienna,  217. 

Routier,  on  blood  in  purpura,  187. 

Rumball,  James,  on  instinct  and  reason,  50 
note. 

Rush,  Dr.,  his  case  of  suspended  cerebral  ac 
tivity,  837. 


S. 


Sadler,  Mr.,  on  proportion  of  sexes,  1015. 
Sanders,  Dr.,  on  structure  of  spleen,  456-458. 
Sanders,  Mr.  E.,  on  dentition,  296-298. 
Savart,  M.,  on  production  of  musical  tones,, 
907. 


1070 


INDEX   OF   AUTHORS. 


Scharling,  Prof.,  on  excretion  of  carbonic 
acid,  528,  529  ;  on  amount  of  carbon  ex- 
creted, 530. 

Scherer,  Prof.,  his  researches  on  casein,  56 ; 
on  inosite,  77;  on  hypoxanthine,  87;  on 
acetic  acid  in  juice  of  flesh,  90;  on  urine- 
pigments,  91  ;  on  absorbent  power  of 
haematin,  161;  his  method  of  analyzing 
the  blood,  171,  172  ;  on  the  hue  of  the 
:  cd  corpuscles,  181 ;  on  yellow  fibrous 
tissue,  225. 

SchifF,  on  lesion  of  Thalami  Optici,  709  ;  on 
Corpora  Striata,  709 ;  on  Crura  Cerebri, 
709  ;  on  Cerebellum,  733. 

Schleisner,  Dr.,  on  sanitary  condition  of  Ice- 
land, 382,  545. 

Schlossberger  and  Kemp,  on  proportion  of 
nitrogen  in  alimentary  substances,  378. 

Schmidt,  on  diameter  of  dried  blood-cor- 
puscles, 160;  on  serous  effusions,  231  ;  on 
digestive  process,  419. 

Schneider,  Dr.,  his  case  of  electric  disturb- 
ance, 640. 

Schreger,  on  absorption  by  cutaneous  lym- 
phatics, 448. 

Schroeder  Van  der  Kolk,  on  coagulation  of 
blood,  196. 

Schultze,  on  reaction  of  oleine,  95. 

Schwann,  Prof.,  on  force  of  muscular  con- 
traction, 328,  329 ;  on  peripheral  termina- 
tions of  nerve-fibres,  342;  on  division  of 
bile-duct,  431. 

Seebeck  and  Wartmann,  on  Daltonism,  893. 

Serres,  M.,  on  comparative  anatomy  of  Cere- 
bellum,729;  on  pathology  ofCerebellum,738. 

Sharpey,  Prof.,  on  motion  of  particles  within 
cells,  130;  on  mucous  membranes,  232; 
on  cartilage,  260  ;  on  structure  of  animal 
basis  of  bone,  270  ;  on  intra-membranous 
ossification,  272 ;  on  formation  of  lacunae 
and  canaliculi  of  bone.  277;  on  structure 
of  fibrillae  of  muscle,  305,  306  ;  on  develop- 
ment of  muscle,  313  ;  on  sympathetic  nerve- 
fibres,  338  note;  on  peripheral  terminations 
of  nerve-fibres,  342 ;  on  formation  of  de- 
cidua,  972. 

Sibson,  Dr.,  on  mechanism  of  respiration,  521 
note. 

Simpson,  Dr.,  on  pathology  of  Cerebellum, 
739. 

Simpson,  Prof.,  on  analogy  between  puer- 
peral and  surgical  fever,  217  ;  on  regene- 
ration ofvlimbs,  561  ;  on  parturition,  982 
note ;  on  hermaphrodism,  referred  to,  1005 
note. 

Simon,  Dr.,  on  action  of  bile,  &c.  on  blood- 
corpuscles,  162;  on  blood  of  renal  vessels, 
184;  on  blood  in  typhus,  187;  on  meco- 
nium,  590;  on  variations  in  urine,  601  ;  on 
variations  in  milk,  1024. 

Sirnon,  Mr.,  on  nature  of  fibrin,  63  note ;  on 
free  nuclei,  137;  on  cancer-cells,  141;  on 
coagulation  of  blood  in  the  vessels,  197;  on 
thymus  gland,  461 ;  on  cancerous  cachexia, 
574  note. 

Simon,  on  mechanism  of  respiration,  521  note. 

Sion,  Dr.,  his  case  of  fat  in  the  blood,  190. 

Sloan,  Dr.,  his  case  of  protracted  abstinence, 
397. 

Smith,  Dr.  Andrew,  on  Bushmen,  1050. 

Smith,  Dr.  Southwood,  on  cutaneous  absorp- 
tion, 446;  on  cutaneous  transpiration,  612. 


Smith,  Dr.  Tyler,  on  post-mortem  contrac- 
tion of  uterus,  334;  on  cause  of  parturition, 
982  note. 

Smith,  Mr.  R.  A.,  on  pulmonary  exhalation, 
533. 

Smith,  Mr.  Richard,  his  case  of  blunted  sensi- 
bility, 850  note;  on  metallic  tractors,  948 
note. 

Smith,  Rev.  Sydney,  on  emotions,  763. 

Snow,  Dr.,  his  experiments  on  respiration, 
524. 

Solly,  Mr.  S.,  on  Medulla  Oblongata,  679  ;  on 
the  brain,  694,  704  note  ;  on  optic  chiasma, 

Spallanzani,  on  fertilizing  power  of  sperma- 
tozoa, 955  note. 

Spencer,  Earl,  his  cases  of  protracted  gesta- 
tion, 982,  983. 

Stadeler,  on  carbonaceous  acids  of  urinary 
extractive,  539  note,  604. 

Stanley,  Mr.,  his  case  of  softening  of  Spinal 
Cord,  669. 

Stark,  Dr.,  on  composition  of  bone,  271. 

Stilling,  on  structure  of  Spinal  Cord,  662,  665  ; 
on  columns  of  Spinal  Cord,  669. 

Stokes,  Dr.,  on  muscular  contractions  in 
phthisis,  &c.,  328;  on  evolution  of  light, 
o3z. 

Strecker,  on  constitution  of  hippuric  acid, 
87;  on  biliary  acids,  94-96. 

Symonds,  Dr.,  on  volitional  actions,  768  note  ; 
on  death,  referred  to,  1057  note. 


T. 


Thackrah,  Mr.,  on  coagulation  of  blood,  196, 
198. 

Taylor,  Dr.  A.,  on  precipitation  of  gelatin, 
68  ;  on  poisonous  change  in  meat,  387  ;  on 
protracted  gestation,  referred  to,  983  note. 

Taylor,  Mr.,  on  Duverney's  glands,  962  note. 

Tessier,  M.,  his  cases  of  protracted  gestation, 
983. 

Theile,  Prof.,  on  hypospadias,  1005  note. 

Thomson,  Prof.  A.,  on  proportion  of  water 
in  the  tissues,  100;  on  intestinal  glandulae, 
240,  434,  435  ;  on  contraction  of  muscle, 
307;  on  Peyerian  glands,  434,  435;  on 
double  monstrosity,  557  note,  949. 

Thompson,  Dr.  R.  D.,  on  presence  of  sugar 
in  blood,  76 ;  on  milky  serum,  176  ;  on 
gastric  juice,  418. 

Tiedemann  and  Gmelin,  MM.,  on  action  of 
bile  in  digestion,  431;  their  experiments  on 
absorption,  444. 

Tilanus,  on  saliva,  414  note. 

Tod,  Mr.,  on  duration  of  irritability  of  heart* 
468. 

Todd,  Dr.,  on  structure  of  mucous  membrane 
of  stomach,  415;  on  artificial  epilepsy,  711 ; 
on  Commissures  of  Cerebrum,  746;  on  deli- 
rium, 805 ;  on  chorea,  836 ;  on  epilepsy, 
842;  on  general  physiology  of  Nervous  Sys- 
tem, referred  to,  847  note  (see  Todd  and 
Bowman). 

Todd  and  Bowman,  on  areolar  tissue,  226  note; 
on  structure  of  cuticle,  248  ;  on  ossification, 
277  ;  on  enamel-pulp,  289  ;  on  fibres  of  ol- 
factory nerve,  337;  on  conducting  power 
of  nerves  for  electricity,  357  ;  on  polar 
character  of  nerve-force,  358  ;  on  muscular 


INDEX   OF   AUTHORS. 


1071 


layer  of  bronchial  tube,  606  ;  on  structure 
of  Spinal  Cord,  665;  on  muscular  tension, 
700 ;  on  peculiar  excitability  of  frog,  701 
note  ;  on  corpora  striata  and  thalami  optici, 
705 ;  on  papillae  of  tongue,  865,  866  ;  on 
olfactory  nerve,  871,  872  ;  on  adaptation  of 
eye  to  distances,  876 ;  on  cochlear  nerve, 
896. 

Tomes,  Mr.,  on  granular  structure  of  bone, 
270  ;  on  ossification,  277  ;  on  ununited  frac- 
ture, 282  ;  on  structure  of  dentine,  284,  285; 
on  calcification  of  dentine,  287,  288  ;  on 
formation  of  enamel,  289. 

Toynbee,  Mr.,  on  nutrition  of  cartilage,  261  ; 
on  vessels  of  cornea,  264;  on  structure  of 
kidney,  referred  to,  595  note  ;  on  membrana 
tympani,  899. 

Traill,  Dr.,  on  fat  in  the  blood,  190. 

Travers,  Mr.,  on  formation  of  capillaries,  302. 

Treviranus,  on  complementary  nutrition,  210. 

Trommer,  M.,  on  absorption  of  sugar  into  lac- 
teals,  76. 

Trousseau,  M.,  on  suspended  lactation,  1021. 

Turck,  Dr.,  on  pathological  changes  in  Spinal 
Cord,  836. 

Turley,  Mr.,  his  case  of  excessive  sexual  de- 
sire, 739  note. 


U. 


Unzer,  Prof.,  on  reflex  action,  672;  his  gene- 
ral Physiology  of  the  Nervous  System,  re- 
ferred to,  847  note. 


V. 


Valentin,  Prof.,  his  estimate  of  amount  of  blood, 
155  ;  on  filtration  of  albuminous  fluids,  231  ; 
on  development  of  muscle,  313;  on  post- 
mortem contraction  of  intestinal  tube,  334  ; 
on  degeneration  of  optic  nerve  and  retina 
from  disuse,  345;  on  sense  of  hunger,  391, 
392  note;  on  movements  of  stomach,  407  ; 
on  movements  of  intestinal  canal,  409 ;  on 
excitement  of  heart's  action  by  irritation  of 
the  pneumogastric,  469  ;  on  sounds  of  heart, 
477  ;  on  amount  of  blood  discharged  from 
heart,  478  ;  on  rate  of  blood's  movement  in 
capillaries,  497;  on  excitability  of  mucous 
surface  of  trachea  and  bronchi,  518;  on 
quantity  of  air  respired,  523  ;  on  interchange 
of  gases  in  respiration,  525  ;  on  columns  of 
spinal  cord,  670  ;  on  roots  of  pneumogastric, 
688;  on  spinal  accessory,  691;  on  hypo- 
glossul,  692  ;  on  cephalic  nerves  generally, 
695;  on  olfactory  nerves,  714;  on  motor 
actions  of  sympathetic  nerves,  830  ;  on  tac- 
tile sensibility,  859;  on  evolution  of  ovum, 
958  ;  on  discharge  of  ovum  from  ovisac,  963. 

Van  Deen,  on  columns  of  Spinal  Cord,  669. 

Vanner,  his  estimation  of  the  quantity  of  blood, 
155. 

Verdeil,  on  creatine  and  creatinine  in  blood, 
174;  on  composition  of  ashes  of  blood,  174. 

Vierordt,  on  quantity  of  air  respired,  523  ;  on 
percentage  of  carbonic  acid  in  expired  air, 
524;  on  circumstances  affecting  this,  526- 
529. 

Villerme,  M.5  on  infantile  mortality,  630.  j 


Virchow,  on  haematoidin,  66  ;  on  fatty  degene- 
ration of  uterus  after  parturition,  553. 

Vogt,  his  cases  of  paralysis  of  fifth  pair,  688  ; 
on  changes  in  germinal  vesicle,  969. 

Volkmann,  Prof.,  on  muscular  contraction,  319; 
on  sympathetic  nerve-fibres,  338  ;  on  glosso- 
pharyngeal  nerve,  403  ;  on  sounds  of  heart, 
476;  on  amount  of  blood  discharged  from 
heart,  478  ;  on  force  of  heart's  contraction, 
481  ;  on  rate  of  pulse  in  the  aged,  481  ;  on 
the  influence  of  stature  on  the  pulse,  481  ; 
on  pressure  of  liquids  within  rigid  tubes, 
487  ;  on  dilatation  of  arteries  by  pulse-wave, 
487  ;  on  transmission  of  pulse-wave,  487  ;  on 
rate  of  movement  of  blood  in  arteries,  488  ; 
on  haemodrometer,  488-489  ;  on  lateral  pres- 
sure of  blood  within  arteries,  490  ;  on  rate 
of  blood's  movement  in  capillaries,  497;  on 
contractility  of  bronchial  tubes,  509;  on  dis- 
crimination of  sensory  impressions,  653;  on 
structure  of  Spinal  Cord,  665-667;  on  motor 
roots  of  pneumogastric,  688;  on  refractive 
power  of  eye,  883. 

Von  Ammon,  Dr.,  on  influence  of  passion  on 
mammary  secretion,  944,  945. 

Vrolik,  Prof.,  on  double  monstrosity,  557  note, 
949  ;  on  varieties  in  form  of  plevia,  1036. 


W. 


Wade,  Sir  Claude,  his  case  of  Trance,  1058 
note. 

Wagner,  Prof.,  on  termination  of  nerves  in 
muscle,  312  note  ;  on  motor  roots  of  pneu- 
mogastric, 688  ;  on  tactile  papilla?,  858  ;  on 
spermatozoa,  954,  955  ;  on  changes  in  ger- 
minal vesicle,  969. 

Wallace,  Dr.  Clay,  on  adaptation  of  eye  to 
distances,  876. 

Waller,  Dr.,  on  papillae  of  tongue,  238,866  note; 
on  degeneration  of  nerve-fibres  after  section, 
346  ;  on  influence  of  sympathetic  over  move- 
ments of  pupil,  831. 

Wallis,  Mr.,  his  case  of  deficient  encephalic 
power,  363,  400  note. 

Walshe,  Dr.,  on  cancerous  cachexia,  574  note. 

Ward,  Mr.,  on  movements  after  death  from 
cholera,  327. 

Wardrop,  Mr.,  on  influence  of  passion  on  mam- 
mary secretion,  945  note. 

Wartmann  and  Seebeck,  on  Daltonism,  893. 

Wasmann,  on  pepsin,  419,  420. 

Watson,  Dr.,  on  absorption  of  vapor,  447. 

Weber,  Profrs.,  on  development  of  blood-cor- 
puscles in  liver,  167,  450  ;  on  muscular  con- 
traction, 308,  318;  on  epithelium-cells  of 
intestinal  villi,  441  ;  on  arrestment  of  heart's 
action  by  electro-magnetic  current,  470  ;  on 
effects  of  electro-magnetic  current  on  small 
arteries,  484;  on  capillaries,  494;  on  ac- 
celeration of  blood  by  contraction  of  arteries, 
487  ;  on  rate  of  blood's  movements  in  capil- 
laries, 497  ;  on  size  of  pulmonary  air-cells, 
507  ;  on  tactile  sensibility,  859-861  ;  on 
sensibility  of  tongue,  864;  on  sounds  of  vi- 
brating reeds,  930  ;  on  formation  of  decidua, 
972,  974;  on  vesicula  prostatica,  1003,  1005 
note  ;  on  varieties  of  form  of  pelvis,  1036. 

Webster,  Dr.,  his  case  of  softening  of  Spinal 
Cord,  669. 


1072 


INDEX   OF   AUTHORS. 


Wheatstone,  Prof.,  on  Stereoscope,  885-888  ; 
on  falsetto  voice,  933. 

White,  Mr.,  his  case  of  reproduction  of  super- 
numary  thumb,  561. 

Whitehead,Mr.,  on  menstrual  fluid,  960. 

Williams,  Dr.  C.  J.  B.,  on  destruction  of  blood- 
corpuscles,  188 ;  on  colorless  corpuscles, 
205;  on  ulceration  of  Peyerian  glandulse, 
221,  435  note;  on  elimination  of  morbid 
poisons,  222;  on  force  required  to  propel 
the  blood,  467  ;  his  experiments  on  the  toni- 
city  of  bloodvessels,  485,  488,  499 ;  on  con- 
tractility of  bronchial  tubes,  509,  510  ;  on 
maintenance  of  animal  heat  by  artificial  re- 
spiration, 626;  on  death,  1057  note;  from 
necraemia,  1056. 

Wilson,  Dr.  G.,  on  fluorine,  104. 

Williams,  Dr.  Robert,  on  morbid  poisons,  222. 

Williams,  Dr.  T.,  on  hepatic  follicles,  582;  on 
disintegration  of  hepatic  cells,  590. 

Wilson,  Mr.  E.,  on  follicular  parasite,  244  ;  on 
growth  of  nails,  250,  251  ;  on  diameter  of 
hair,  251  ;  on  muscular  fibrilla,  305,  306 
note  ;  on  congestion  of  liver,  588  note ;  on 
sudoriparous  glandulse,  6]  1. 


Willis,  Mr.,  on  the  voice,  935  ;  his  artificial 

glottis,  931 ;  on  vowel  sounds,  937. 
Wollaston,  Dr.,  on  development  of  sound  by 

muscular  contraction,  330 ;  on  optic  chiasma, 

717  note. 

Wright,  Dr.,  on  composition  of  saliva,  412. 
Wrisberg,  on  loss  of  blood,  155. 
Wohler,  on  urea  in  humors  of  eye,  82;   on 

metamorphosis  of  uric  acid,  84  ;  on  action 

of  soluble  salts  on  kidneys,  609. 


Y. 


Yarrell,  Mr.,  on  assumption  of  male  plumage 
by  female,  212. 


Z. 


Zanarelli,  on  fat  in  the  blood,  190. 
Zander,  on  succus  entericus,  432. 
Zimmermann,  Dr.,  on  effect  of  saline  solutions 

on  fibrin,  60;  on  nature  of  fibrin  63  note; 

on  effects  of  loss  of  blood,  178. 
Zwicky,  on  organization  of  blood-clot,  194. 


INDEX  OF  SUBJECTS. 


ABERRATION,  spherical  and  chromatic,  874. 

Abnormal  forms  of  Nutritive  process,  566-574; 
inflammation,  566-572;  tuberculosis,  572- 
574;  heterologous  growths,  573. 

Abortion,  981. 

Abscesses,  formation  of,  567-572. 

Absence  of  Mind,  797. 

Absorbent  Cells,  439,  441. 

System,  438, 439, 451;  movement  of  fluids 

through,  454,455. 

Vessels,  structure   and  development  of, 

298  ;  see  Lacteals,  and  Lymphatics. 

ABSORPTION,  general  nature  of  the  function, 
365,  438,  439;  by  bloodvessels  of  intes- 
tinal surface,  439,  440,443-445;  by  lac- 
teals,  439-442;  by  lymphatics,  445,449, 
451,452;  by  general  sanguiferous  system, 
449-452. 

Of  vapors  by  lungs,  534,  535. 
Of  effete  tissues,  448,  449. 

Abstinence,  entire,  397. 

Abstraction,  mental,  795;  voluntary,  795,  796  ; 
involuntary,  797-799. 

Activity,  varying,  of  nutritive  processes,  554- 
566. 

,  Vital,  conditions  of,  140-148;  variations 
of,  with  age,  149-153;  relation  of  to  dura- 
tion of  organism,  134,  554;  to  amount  of 
heat  supplied,  143-146. 

Acardiac  fetus,  movement  of  blood  in,  493. 

Acidity  of  the  urine,  608-609. 

Adaptiveness  of  movements  no  proof  of  sensa- 
tion, 674. 

Adhesion  between  cut  surfaces,  562 ;  second- 
ary, 565. 

Adipocere,  71. 

Adipose  Tissue,  structure  of,  256,  257;  devel- 
opment of,  258,  259;  uses  of,  259. 

Adult  age,  peculiar  attributes  of,  152. 

Aeration,  see  Respiration. 

Afferent  nerve-fibres,  651,  653. 

Affinities,  Chemical,  operation  of,  in  the  living 
body, 112. 

Age,  influence  of,  on  nutritive  activity,  149- 
153;  on  rate  of  pulse,  481  ;  on  excretion  of 
carbonic  acid,  530;  on  excretion  of  urea, 
602 ;  on  power  of  calorification,  629-631. 

of  Foetus,  means  of  determining,  1012, 

1013. 

Air,  amount  of,  used  in  respiration,  522-523; 
changes  in  proportions  of  oxygen  and  car- 


bonic acid,  524-525;  amount  of  carbonic 
acid  imparted  to,  526-531 ;  changes  in  pro- 
portion of  nitrogen,  531,  532;  watery  vapor 
imparted  to,  533,  535. 

Air-cells  of  lungs,  structure  of,  504,  505. 

Albinoism,  1030. 

Albumen,  composition  and  properties  of,  54, 55 ; 
its  presence  in  the  solids  and  fluids  of  the  body 
generally,  56 ;  conversion  of,  into  fibrine,  60- 
64,157,161.453;  normal  proportion  of,  in 
blood,  161-170;  variations  in  amount  of,  in 
disease,  184;  its  uses,  54,  63,  205,  206. 

Albuminose,  182,  427. 

Albuminous  Compounds,  53,  91. 

principles  of  Food,  376-385. 

Albuminuria,  blood  in,  189. 

Alcohol,  rapid  absorption  of,  443. 

Alcoholic  drinks,  their  effects  on  the  system, 
389-390 ;  uses  of,  in  Fever,  624. 

Alfourous,  1052. 

Aliment,  sources  of  demand  for,  363,  364  ;  see 
Food. 

Alimentary  canal,  development  of,  999. 

Alkaline  Carbonates,  uses  of,  in  the  system, 
103,  107. 

Phosphates,  uses  of,  in  the  system,  108; 

presence  of,  in  urine,  606;  amount  of,  pro- 
portional to  waste  of  nervous  matter,  355. 

Sulphates,  presence  of,   in   the   system, 

110  ;  in  urine,  605. 

Alkalinity  of  the  urine,  607,  608. 

Allantoin,  84. 

Allantois,  development  of,  993,  994 ;  formation 

of  urinary  bladder  from,  1002. 
Alloxan,  84. 

American  races,  1050,  1051. 
Ammonia,  a  product  of  decomposition,  109. 
Amnion,  formation  of,  990,  991. 
Amphibia,  spinal  cord  of,  663. 
Amphioxus,  nervous  system  of,  646,  706. 
Anaemia,  state  of  blood  in,  186. 
Analysis  of  Blood,  different  methods  of,  170- 

172;  in  disease,  185. 
Ancon  breed  of  sheep,  1037  note. 
Animal  Functions,  371  ;  their  relations  to  the 

Organic,  372-374. 

Heat;  see  Heat,  Animal. 

Magnetism  ;  see  Mesmerism. 

Anterior  Columns  of  Spinal  Cord,  structure  of, 

659-661;   functions  of,  668-671. 
Commissure,  742. 

Pyramids  of  Medulla  Oblongata,  677-681. 

Anthropomorphism,  794-795. 


1074 


INDEX   OF   SUBJECTS. 


Aorta,  development  of,  992 ;  contraction  of, 
produced  by  irritation  of  Sympathetic,  470. 

Aplastic  exudations,  569,  570. 

Aponeuroses,  structure  of,  224. 

Apoplexy,  stale  of  blood  in,  187. 

Apparent  Death,  1057. 

Arab  races,  1044. 

Arciform  fibres,  677. 

Area  germinativa,  989. 

pellucida,  989. 

vasculosa,  991. 

Areolar  Tissue,  structure  and  composition  of, 
226;  development  of,  227. 

Arian  race,  1043-1046. 

Arrest  of  Development,  548;  of  circulating 
apparatus,  999  ;  of  sexual  organs,  1004  ;  of 
visceral  arches  of  face,  1008  note. 

Arsenic,  occasional  presence  of,  in  the  body, 
110;  elimination  of,  111,215. 

Arterial  and  Venous  blood,  differences  of,  181- 
185. 

system,  first  development  of,  995,  996; 

subsequent  changes  in, 997-998. 

Arteries,  movement  of  Blood  in,  482-490  ;  di- 
ameters of,  482 ;  properties  of  coats  of,  226, 
483;  irritability  of,  483  ;  influence  of  nerves 
upon,  483;  influence  of  electrical  and  other 
stimuli  on,  484;  tonicity  of,  485  ;  regulation 
of  diameter  of,  486  ;  elasticity  of,  486,  487  ; 
pulsation  of,  487,  488;  rate  of  movement  of 
blood  in,  488,489;  lateral  pressure  of  blood 
in,  490. 

Articulate  sounds,  production  of,  935-940 ; 
vowels,  935-937  ;  consonants,  937. 

Articulation,  movements  of,  guided  by  sensa- 
tions, 722,  723,  934. 

Artificial  Respiration,  partial  sustenance  of 
heat  by,  626. 

Arum,  liberation  of  heat  by  flowers  of,  621. 

Arytenoid  cartilages,  movements  of,  925-927. 

muscles,  actions  of,  927,  928. 

Asphyxia,  pathology  of,  535-537;  in  relation 
to  capillary  circulation,  493,  494  ;  death  by, 
535,  1056. 

Assimilation,  general  nature  of  the  function, 
365,  366. 

Association  of  Ideas,  laws  of,  775-780. 

Asthenia,  death  by,  1056. 

Asthma,  spasmodic,  pathology  of,  846. 

Atlantidae,  1044. 

Atrophy,  547  ;  conditions  of,  558-560. 

Attention,  state  of,  780,  781  ;  its  share  in  per- 
ception, 759 ;  in  higher  intellectual  pro- 
cesses, 788  ;  voluntary,  795,  796  ;  influence 
of,  on  intensity  of  sensations,  849,  850,  855, 
856 ;  in  producing  muscular  movements,  920 
-924;  on  organic  changes,  947,  948. 

Auditory  Ganglia,  680,  702 ;  functions  of,  708. 

— —  Nerves,  endowments  of,  717;  ultimate 
distribution  of,  894-896. 

Auricles  of  Heart,  action  of,  472-474  ;  capacity 
of,  475. 

Australian  race,  1053. 

Automatic  actions,  of  Spinal  Axis,  695-699;  of 
Sensory  Ganglia,  719-722  ;  their  instrument- 
ality in  voluntary  movement, 722-728  ;  of  Ce- 
rebrum, 774,  775,  788,  789  ;  sleep  prevented 
by  them,  8 19, 820;  of  Nervous  System  in  gene- 
ral, 831 ;  their  subordination  to  the  Will,  831. 

Axioms,  fundamental,  of  human  thought,  785- 
788. 

Azote ;  see  Nitrogen. 


B. 


Barclay,  Capt.,  case  of,  822. 
Barrackpore,  mortality  in  barracks  at,  544. 
Basement-membrane,  139. 
Basque  race,  1043,  1044. 
Beauty,  elementary  notion  of,  785. 
Bee,  manifestations  of  instinct  in,  643,  749  ; 
modification    of   development    by    food   in, 
212  ;  development  of  heat  in,  622. 
Berber  races,  1044. 
Bellary,  cholera  at,  541. 
Benzoic  Acid,  87. 

Bile,  secretion  of,  from  venous  blood,  591  ; 
excrementitious  nature  of,  592,  594  ;  partly 
formed  from  products  of  disintegration,  98, 
591,  592  ;  in  part  from  newly-absorbed  ma- 
terials, 592;  effects  of  suspension  of,  592, 
593 ;  reabsorption  of,  592  ;  general  composi- 
tion of,  593;  individual  components  of,  94- 
98  ;  quantity  of,  secreted,  431 ;  uses  of,  in 
digestion,  430,  431. 
Bile-Pigment,  96,  97. 

Biliary  cells,  587;  fatty  degeneration  of,  589, 
590. 

secretion,  metastasis  of,  579,  580. 

Bilifulvin,  97. 
Bilin,  95. 
Biliphsein,  96. 
Biliverdin,  97. 

Biological  state,  phenomena  of,  797-799.     » 
Birds,  temperature  of,  622;  effects  of  starvation 
on,  623,  624;  spinal  cord  of,  663;  sensory 
ganglia  of,  706-709;    cerebellum  of,  729; 
cerebrum  of,  746,  747,  1009;   intelligence 
and  eclucability  of,  749,  750. 
Binoxide  of  protein,  64,  65. 
Bladder,  contraction  of,  318,  410. 
Blastema,  formative,  127.  128  ;  fibrillation  of. 

228. 

Blastodermic  vesicle,  989. 
Blind  persons,  acuteness  of  touch  in,  862. 
BLOOD,  general  purposes  of,  in  the  economy, 
153,  154  ;  quantity  of,  in   Man,  154,  155  ; 
physical  characters  of,  156,  157. 
Chemical  Composition  of,  170-174;  modifi- 
cation of,  by  age,  174,  175  ;  by  sex,  175; 
by  food   and  drink,  176,  177;  by  loss  of 
blood,   178  ;   differences  of  Arterial  and 
Venous,  178-181 ;   peculiarities  of  portal 
blood,  181,  182;   of  splenic   blood,  182, 
183;  of  hepatic  vein,  183,  184;  of  renal 
vein,  184. 

Pathological  Conditions  of,  184-191  ;  in- 
crease of  fibrin,  185,  186;  diminution  of 
fibrin,  186, 187;  increase  of  red  corpuscles, 
187;  diminution  of  red  corpuscles,  188; 
increase  of  colorless  corpuscles,  188 ; 
diminution  of  albumen,  189;  increase  of 
fatty  matter,  189,  190;  altered  proportion 
of  salts,  190;  increase  and  diminution  of 
water,  190  ;  presence  of  poisons  in,  191  ; 
alterations  of,  in  inflammation,  185-190, 
567-569;  buffy  coat  of,  198-200;  inflam- 
matory effusions  from,  569-572. 
Vital  Properties  of,  191,  192;  coagulation 
of,  193-198  (see  Coagulation)  ;  us*  s  of 
fibrin  of,  201-202;  uses  of  corpuscles  of, 
203-206 ;  uses  of  albumen  of,  207  ;  uses 
of  fatty  matters  of,  207  ;  uses  of  inorganic 
components  of,  208 ;  purification  of,  by 
excretory  processes,  209,  210;  composi- 


INDEX  OP   SUBJECTS. 


1075 


tion  of,  determines  nutritive  operations, 
211,  212;  life  of,  212,  221 ;  self-maintain- 
ing power  of,  213;  elimination  of  poisons 
from,  214-215  ;  contamination  of,  by  mor- 
bid poisons,  215-222. 

Blood  of  Mother,  influence  of  state  of,  on  em- 
bryonic development,  969,  970,  1011,  1012. 

Blood-Corpuscles,  Red,  form,  size,  and  aspect 
of,  157-159;  composition  of,  160,  161  ;  in- 
fluence of  reagents  on,  162;  tendency  to 
aggregation  of,  163;  production  of,  165;  de- 
velopment of,  in  embryo,  165,  166;  subse- 
quent development  from  lymph-corpuscles, 
167-170;  change  of  color  in,  by  respira- 
tion, 180,  181;  their  uses,  203,  204;  varia- 
tions in  amount  of,  in  disease,  187,  188; 
destruction  of,  188 ;  mutual  attraction  of,  in 
coagulation,  193,  199;  adhesion  of,  to  walls 
of  vessels,  494. 

Colorless,  form,  size,  and  aspect  of,  163, 

164;  changes  of  form  of,  164;  numerical 
proportion  of  to  red,  164, 165;  development 
of,  into  red,  167-170;  their  uses,  204-206; 
variations  in  amount  of,  in  disease,  188, 
189. 

Bloodvessels,  development  of,  in  vascular  area, 
165,  300,  991  (see  Arteries,  Veins,  and  Ca- 
pillaries}. 

Bone,  structure  of,  267-269 ;  composition  of, 
270-272;  development  of,  272-277  ;  growth 
of,  279,  280;  irregular  production  of,  280, 
281 ;  regeneration  of,  281,  282. 

Brain;  see  Cerebrum,  Cerebellum,  and  Sensory 
Ganglia. 

Branchial  arches,  992. 

Breeds  of  animals,  origination  of  new,  1037. 

Bronchial  tubes,  contractility  of,  509,  510. 

Brunner's  Glands,  240,  428. 

Buffy  coat  of  blood,  198-200. 

Bulbus  arteriosus,  992. 

Bushmen  of  Southern  Africa,  1040, 1049,  1050. 

Butyrin,  1023. 


C. 


Caco-plastic  deposits,  572. 

Calcium,  fluoride  of,  its  presence  in  the  body, 
104. 

Calcutta,  Black  Hole  of,  538. 

Callus,  formation  of,  282. 

Calorification,  theory  of,  628,  629  (see  Heat, 
Animal). 

Canaliculi  of  Bone,  269  ;  formation  of,  276,  277. 

Cancelli  of  Bone,  267. 

Cancerous  growths,  558,  573. 

Capacity,  germinal,  149;  gradual   diminution 
of,  with  advance  of  life,  150-153. 

vital,  of  Respiration,  521-522. 

Capillarity,  influence  of,  on  chemical  reaction, 
116. 

Capillary  Bloodvessels,  structure  of,  298,  299  ; 
offices  of,  299,  300  ;  development  of,  300- 
302. 

Circulation  of  blood  in,  491-497;  continu- 
ous flow  through,  500;  independent  of 
heart's  propulsion,  492,  493;  variations 
in  movement,  not  influenced  by  heart, 
493 ;  influence  of  alterations  in  diameter 
on,  494,  495;  general  doctrine  of,  495, 
496 ;  effect  of  shock  on,  496,  497 ;  rate 
of  movement  in,  497. 


Carbolic  acid,  539  note. 

Carbonate  of  Lime,  uses  of,  in  the  body, 
103. 

Magnesia,  its  presence  in  the  body,  110. 

Carbonic  Acid,  in  Blood,  179;  absorption  of, 
by  serum,  108;  by  red  corpuscles,  162; 
sources  of  production  of,  in  System,  502- 
504;  its  exchange  for  oxygen  in  respiration, 
524-525;  quantity  of,  generated,  525-530; 
extrication  of,  by  skin,  529,  530  ;  elimina- 
tion of,  by  atmosphere  of  nitrogen  or  hydro- 
gen, 531. 

Cartilage,  simple  cellular,  259,  260  ;  duplica- 
tion of  cells  of,  126  ;  nutrition  of,  261-263; 
ulceration  and  reparation  of,  261  ;  fibrous. 
260. 

Casein,  chemical  composition  and  properties 
of,  56,  57. 

of  human   milk,  peculiarities  of,  1023, 

1024. 

Catalepsy,  state  of,  1058;  rigidity  in,  828. 
Catamenial  flow,  see  Menstruation. 
Caucasian  race,  1042  ;  color  of,  1031. 
Cause,  proper  meaning  of  the  term,  35. 
Cell-Force,  manifestations  of,  129,  130,  133. 
Cells,  the   types  of  Organization,   358;   inde- 
pendent life  of,  124,  358  ;  general  history 
of,  120-136;  form  of,  121  ;  wall  of,  121; 
contents  of,   122;  nuclei   of,  123;  multi- 
plication   of,    by   duplication,   125,    126; 
endogenous   development   of,   126,   127; 
development  of,  in   blastema,   127,  128; 
evolution  of,  from  granules,  128. 
Vital   operations  of,   129  ;  changes  of  form 
of,  129-131 ;  movement  of  particles  with- 
in, 130;    motility   of,    130,  131;    ciliary 
movement  of,  131  ;  development  of  nerve- 
force  by,  132,  133  ;  reciprocity  of  actions 
of,  133,  134;  duration  of,   134,  135;  in- 
fluence of  physical  and  chemical  forces 
on,  135-137. 
Cellular  tissues,  albuminous   composition  of, 

63,  112. 

Celtic  race,  1043. 

Cementum,  structure  of,  286,  287  ;   composi- 
tion of,  286  ;  development  of,  290. 
Cephalic  Ganglia  of  Invertebrata,  706. 

Nerves,  general  character   and  relations 

of,  693,  695. 

Cerebellum,  general  structure  an'd  relations  of, 
947;  particular  account  of,  728-740;  rela- 
tive development  of,  in  different  animals, 
729-732;  results  of  experiments  on,  732, 
733;  pathological  phenomena  of,  733,  734  ; 
its  instrumentality  in  co-ordinating  move- 
ments, 728-734  ;  supposed  by  some  to  be 
seat  of  sensation,  734,  735  ;  by  others  to  be 
organ  of  sexual  instinct,  735 ;  facts  in  oppo- 
sition to  this  view,  736-738  ;  probably  con- 
tains centre  of  sexual  sensation,  739,  740; 
but  not  the  seat  of  desires  and  emotions 
prompted  by  this,  740. 
Cerebration,  unconscious,  784,  790-792. 
Cerebric  Acid,  75. 
Cerebro-spinal  fluid,  747. 

Cerebrum,  general  structure  and  physiological 
relations  of,  374,  647,  741,  832;  patho- 
logical relations  of,  833-836 ;  its  relative 
inferiority  to  sensory  ganglia  in  lower 
animals,  705,  706. 

Leading  features  of  its  structure,  741-746  ; 
comparative  weight  of,  in  different  animals, 


1076 


INDEX   OF   SUBJECTS. 


746, 747;  peculiarity  of  its  circulation,  501; 
immediate  dependence  of  its  activity  on 
supply  of  blood,  353. 

Its  functional  relation  to  Intelligence,  as 
contrasted  with  Instinct,  748-754;  its  ope- 
rations excited  by  reception  of  Sensations, 
754,755;  but  not  themselves  necessarily 
attended  with  Consciousness,  755-757, 
784,  790-792;  formation  of  Ideas,  755. 
756 :  first  stage  consists  in  Perception, 
758-761  ;  connection  of  Emotional  states 
•with  ideas,  761-769 ;  uniformities  of  men- 
tal action  exhibited  by,  770;  general  rela- 
tion of  its  functional  changes  to  psychical 
activity,  770-774  ;  these  changes  conform- 
able to  law  of  reflex  action,  773,  775,  788, 
789;  influence  of  the  Will  upon  their  suc- 
cession, 775,  788-790,  795-796,  810-814, 
817-818;  growth  of,  in  accordance  with 
its  habitual  action,  776,  783,  792,  810,  812. 
State  of,  in  Sleep,  819,  820 ;  cases  of  sus- 
pended activity  of,  837,  838;  development 
of,  1009,  1010. 
Ceruminous  Glands,  245. 
Chaetodon  rostratus,  instinct  of,  761. 
Chemical  Forces,  operation  of,  in  the  living 

body,  116-118. 

Chiasma  of  Optic  nerves,  714-716. 
Childhood,  peculiar  attributes  of,  151,  152. 
Chimpanzee,  comparison  of,  with  Man,  41-49. 
Chloride  of  Sodium,  a  constituent  of  the  body, 
105;  its  uses  in  the  economy,  105,  106;  its 
presence  in  the  urine,  607. 
Chlorosis,  state  of  blood  in,  188;  buffy  coat  in, 

200. 

Choleic  Acid,  95. 
Cholepyrrhin,  96. 

Cholera,  influence  of  putrescent  Food  in  de- 
veloping, 388;  influence  of  imperfect  Respi- 
ration in  developing,  539-541  ;   movements 
after  death  from,  326,  327. 
Cholesterin,  its  composition  and  properties,  74. 
Cholic  Acid,  94. 
Choloidic  Acid,  95. 
Chondrin,  chemical  composition  and  properties 

of,  67,  68. 
Chorda  dorsalis,  990;  transformation  of,  1005. 

tympani,  participation  of,  in  sense  of  taste, 

718. 

Chordae  vocales,  925  ;  structure  of,  226 ;  length 
of,  919 ;  alterations  in  tension  of,  by  muscular 
action,  926,928;   compared  with    vibrating 
strings,  929,  930  ;  with  flute-pipes,  929,  930  ; 
with  reed  instruments,  931-932  ;  their  mode 
of  vibration  in  falsetto  voice,  933,  934. 
Chorea,  pathology  of,  767,  836. 
Chorion,  formation  of,  971;  villi  of,  974,  975. 
Chromatic  aberration,  874. 
Chyle,  composition  and  properties  of,  451-453; 
corpuscles  of,  453;  absorption  of,  441,  442; 
changes  effected  in,  during  passage  to  tho- 
racic duct,  453,454;  milky  aspect  of,  due 
to  fat,  72;  molecular  base  of,  452,  453. 
Chyme,  formation  of,  by  digestive  process,  424 

-428. 
Ciliary  Ganglion,  684. 

Movement,  131,  236,  237. 

Cineritious  substance  of  brain,  339. 
CIRCULATION,  general  plan  of,  383,  466-467 ; 
action  of  Heart  in,  468-482  (see  Heart)',  ac- 
tion of  Arteries  in,  482-490  (see  Arteries); 
action  of  Capillaries  in,  491-497  (see  Capil- 


laries)-, action  of  Veins  in,  497-500  (see 
Veins)',  peculiarity  of,  in  cranium,  500,  747, 
748;  in  erectile  tissues,  501. 

Circulation,  in  Foetus,  early  type  of,  992-995; 
changes  in  plan  of,  995-996;  plan  of,  in  ma- 
ture foetus,  996,  997. 

of  fluid  within  cells,  130. 

Cirrhosis  of  liver,  589. 

Civilization,  influence  of,  on  form  of  skull, 
1034,  1035;  on  body  in  general,  1036. 

Classification,  mental  tendency  to,  777. 

Clitoris,  development  of,  1004. 

Cloaca,  of  Human  embryo,  1002,  1003. 

Coagulable  lymph,  570;  see  Lymph. 

Coagulation  of  Albumen,  55. 

of  Casein,  56,  57. 

of  Fibrin,  60 ;  circumstances  affecting  it, 

61  ;  its  vital  nature,  62. 

of  Blood,  193-202  ;  essentially  due  to  so- 
lidification of  fibrin,  193  ;  an  act  of  vitality, 
194;  occasional  deficiency  of,  194  ;  retarda- 
tion of,  194-196;  effect  of  external  influences 
on,  194-197;  influence  of  rest,  195;  influence 
of  warmth,  195;  effect  of  neutral  salts,  195; 
non-effect  of  surrounding  atmosphere,  195; 
influence  of  depressed  vitality  or  death  of 
vessels,  196;  influence  of  admixture  of  dead 
matter,  197;  varying  proportions  of  serum 
and  clot,  198. . 

Cochlea,  functions  of,  905. 

Cochlear  nerve,  distribution  of,  896. 

Cod,  brain  of,  647. 

Cod-liver  oil,  rationale  of  its  use,  73,  74. 

Codrington,  Sir  E.,  case  of,  823. 

Coition,  act  of,  in  male,  956;  in  female,  962,963. 

Cold,  influence  of,  on  muscular  tonicity,  331; 
power  of  enduring,  619;  production  of,  by 
cutaneous  exhalation,  631;  death  by,  623, 
624,  1056. 

Coldbath-fields  prison,  cholera  at,  542. 

Coleridge,  automatic  action  of  his  intellectual 
powers,  780  note. 

Colostrum,  1025. 

Color,  variation  of,  in  Man,  1030-1031. 

Coloring  matters  of  Bile,  96,  97. 

of  Urine,  92. 

-  of  Red  Corpuscles,  influence  of  reagents 

on,  180,  181. 

Colorless  Corpuscles,  see  Blood- Corpuscles, 
Colorless. 

Colors,  complementary,  891  ;  modifications  in, 
by  proximity,  892  ;  want  of  power  of  dis- 
crimination for,  892. 

Commissural  fibres  of  Cerebrum,  741-746. 

Commissure,  transverse,  of  Spinal  Cord,  661- 
662. 

Commissures,  case  of  deficiency  of,  746  note. 

Comparison,  mental  tendency  to,  777;  inten- 
tional exercise  of,  788,  789. 

Complemental  Nutrition,  211,  212. 

Complementary  Colors,  891,  892. 

Compound  Association,  law  of,  779. 

Complexion,  variation  of,  in  Man,  1030-1031. 

Conception,  act  of,  979. 

Concussion  of  Brain,  313,  314. 

Conduct,  determination  of,  by  the  will,  811; 
influence  of  motives  on,  812-813. 

Conduction  of  sounds,  897,  898. 

Conjugated  Acids,  87  note. 

Conjugation,  among  simple  cellular  Plants, 
949,  950. 

Conscience,  nature  of,  814-816. 


INDEX   OF   SUBJECTS. 


1077 


Consciousness,  seat  of,  in  the  Sensory  Ganglia, 
706,  707;  probably  not  in  the  Cerebrum,  755 
-757;  perceptive,  757-761 ;  emotional,  761- 
769  ;  intellectual,  769-790. 
Consensual  Actions,  350,  374,  398;  performed 
by  instrumentality  of  Sensory  Ganglia,  648, 
719-722. 

Consonants,  articulation  of,  937-940. 
Constructive  Association,  law  of,  779. 
Contiguous  Association,  law  of,  776. 
Contractility   of  Muscle,   317;   see   Muscular 

Fibre. 
Contraction  of  Muscle,  state  of  fibres  in,  306- 

308 ;  see  Muscular  Fibre. 
Contractions,  Muscular,  after  death,  326,  327  ; 

rhythmical,  319  note. 
Convergence  of  optic  axes,  916. 
Convolutions  of  Brain,  742. 
Convulsive  diseases,  pathology  of,  843-846. 
Copper,  occasional  presence  of,  in  body,  111. 
Copulation,  act  of,  in  male,  956,957;  in  fe- 
male, 962. 
Corium,  structure  of,  241,242;   nutrition   of, 

246. 
Cornea,  structure  of,  263,  264 ;   nutrition  of, 

264,  265. 

Corpora  Malpighiana  of  Spleen,  456;  of  Kid- 
ney, 594-598  ;  uses  of,  599. 

Olivaria,  677-682. 

Pyramidalia,  677-682. 

Quadrigemina,  702 ;  functions  of,  707,  708. 

Restiformia,  677-6S2. 

Striata,  703,  705;  functions  of,  708-710. 

Wolffiana,  1001,  1002. 

Corpus  Callosum,  744;  deficiency  of,  746. 

Dentatum,  678. 

Luteum,  structure  and  formation  of,  863- 

966. 
Corpuscles  of  Blood  (see  Blood-Corpuscles');  of 

Chyle,  453;  of  Lymph,  454. 
Corpuscular  lymph,  570,  571. 
Correlation    of  Vital    and    Physical    Forces, 
141-146;  of  Nervous  and  Electrical  Forces, 
356-358;  of  Nervous   and   Mental  Forces, 
772-775. 
Cortical  substance  of  Brain,  339;  of  Kidney, 

610,  611. 

Coughing,  act  of,  519. 
Cramo-spinal  Axis,  645,  646,  659. 
Cranium,  circulation  within,  500,  747. 
Crassamentum  of  Blood,  157,  193;  proportion 

of,  to  Serum,  198. 
Creatine,  composition  and  properties  of,  89, 
90  ;  sources  of,  in  the  body,  89,  90  ;  its  pre- 
sence in  the  Blood,  174  note;  in  the  Urine, 
604. 

Creatinine,  composition  and  properties  of,  89, 
90  ;  sources  of,  in  the  body,  89,  90  ;  its  pre- 
sence in  the   Blood,  174  note;  an  important 
component  of  Urine,  603. 
Croup-like  Convulsion,  846. 
Croupous  exudation,  570. 

Crura  Cerebri,  effects  of  division  of,  710,  711. 
Crusta  petrosa,  structure  and  composition  of, 

286,  287;  development  of,  290. 
Crustacea,  decapodous,  independent  vitality  ol 

their  spermatic,  cells,  102. 
Crying,  act  of,  518. 
Cryptogamia,  generation  in,  949,  950. 
Crystalline  Lens,  structure  and  nutrition  of,  265 
Cutaneous  Asphyxia,  613,  633,  634. 
Glandulae,  242-245,  611. 

69 


utaneous  Transpiration,  61 1-614 ;  composition 
of,  612;  quantity  of,  612,  613 ;  excrementi- 
tious  nature  of,  613,  614. 
Cuticle,  see  Epidermis. 

Cutis,  structure  of,  241,  242  ;  nutrition  of,  246. 
yclostome  Fishes,  chorda  dorsalis  of,  1005; 
sympathetic  system  of,  659. 
ystine,  93,  94. 

^ysts,  piliferous  and  dentigerous,  558. 
Cytogenesis,  different  modes  of,  125-127. 


D. 


Deaf  and  dumb,  their  want  of  command  over 
muscles  of  vocalization,  722,  723;  their  sign- 
language,  759  note. 

Death,  the  necessary  consummation  of  Life, 
134,  135,  1054;  different  modes  of,  1055- 
1056;  somatic.  1055,  1056;  molecular,  1054- 
1057;  apparent  and  real,  1057,  1058;  signs 
of,  1058,  1059. 

Decidua,  formation  of,  972-974. 
Decline  of  life,  152,  153. 
Decussation  of  Optic  Nerves,  716. 
Defecation,  act  of,  410,  411. 
Degeneration  of  tissues,  549,  550  ;  of  muscular 
substance,  553,  559;  increased  tendency  to, 
in  inflammation,  567,  568;  of  lymph  and  its 
products,  571,  572  (see  Fatty  Degeneration). 
Deglutition,  401-404. 
Deity,  notions  respecting,  786-788. 
Dental  groove,  290-295. 
Dentine,  structure   of,  283-285  ;   composition 

of,  287 ;  development  of,  287,  288. 
Dentition,  first,  290-295;  second,  296,  297. 
Desires,  formation  of,  dependent  on  ideas,  740, 

761. 

Development,  a  source  of  demand  for  nutrition, 
548;  its  difference  from  growth,  548  ;  arrest 
of,  548,  995,  1004,  1008  note. 
Development   of  Embryo,   985-1018;    general 
plan  of,  985-987  ;  earliest  stages  of,  987- 
989;  segmentation  of  yelk,  987-989;  form- 
ation of  blastodermic  vesicle,  989;  founda- 
tion of  vertebral  column,  990  ;   develop- 
ment of  amnion,  991,  994;  vascular  area, 
991  ;  vitelline  vessels,  991  ;  heart  and  ar- 
terial   system,   992,   995-998 ;    allantois, 
993;  umbilical  vessels  and  placental  villi, 
994;  venous  system,  995,  996;  alimentary 
canal,  999  ;  liver,  999,  1000  ;  lungs,  1000- 
1001  ;   urinary  organs,  1001,  1002;  gene- 
rative   apparatus,    1002-1005;    skeleton, 
1005,  1006:  cranium,  1007,  1008;  nervous 
centres,  1008-1010;  cephalic  nerves,  693, 
695;  eye,  1010;  ear,  1010_,  1011 ;  spleen, 
458;  suprarenal  bodies,  459,  460;  thymus 
gland,  460,  461 ;  thyroid  gland,  461. 
Influence  of  mother  on,  1011,  1012. 
General  progress  of,  1012-1017. 
Development  of  Tissues,  120  ;  fibrous,  138,  139, 
227,  228;  epithelium,  237;  glandular  folli- 
cles, 239,  240  ;    sebaceous   glandulae,  244  ; 
epidermis,  248  ;  nails,  250,  251  ;  hair,  254- 
256;   fat-cells,  256;    cartilage,  261;    bone, 
272-277;   dentine,  287,  288;   enamel,  288, 
289;  cementum,  290;   milk-teeth.  291-295  ; 
permanent  teeth,  295-297  ;  capillary  blood- 
vessels, 300-302  ;  absorbents,  302  ;  muscular 
fibres,  313-315;  nervous  tissue,  346. 
Deutencephalon,  1009. 


1078 


INDEX    OF   SUBJECTS. 


Diabetic  sugar,  77  note. 

Diaphragm,  movements  of,  511. 

Diarrhoea,  eliminative  agency  of,  437,  438. 

Dichrotous  pulse,  4S7. 

Diet,  animal  and  vegetable,  379-381 ;  influence 
of,  on  composition  of  blood,  177,  178;  of 
urine,  602-605. 

Diet-scales,  384,  386. 

Dietetics,  general  principles  of,  381-383. 

DIGESTION,  general  nature  of,  364,  365. 

Gastric,  424-427;  a  process  of  chemical  so- 
lution, 424  ;  influence  of  various  conditions 
on,  425,  427;  limited  to  azotized  sub- 
stances, 426. 

Intestinal,  428-433  ;  influence  of  pancreatic 
fluid  in,  428,  429;  influence  of  bile  in,  430, 
431  ;  influence  ofsuccus  entericus  in,  429, 
432,  433. 

Direction,  visual  appreciation  of,  883;  auditory 
appreciation  of,  908. 

Discus  proligerus,  958,  963,  971,  972. 

Disintegration  of  tissues,  continual  during  life, 
134,  361,  546,  549,  550,  552-554. 

Distance,  visual  appreciation  of,  888,  889 ;  au- 
ditory appreciation  of,  908. 

Diuretic  medicines,  influence  of,  609-611. 

Diverging  Appendages  of  vertebra,  1006. 

Divining-rod,  rationale  of,  922,  923. 

Dominant  ideas,  influence  of,  in  determining 
the  course  of  thought,  796,  798,  800,  811. 

Double  Monsters,  557,  949. 

Draught  in  mammary  gland,  943. 

Dreaming,  phenomena  of,  802-804,  811. 

Dublin  Lying-in  Hospital,  high  rate  of  mor- 
tality in,  545. 

Ductless  Glands,  456  ;  see  Spleen,  Suprarenal, 
Thymus,  and  Thyroid  bodies. 

Ductus  Arteriosus,  995,  998. 

Cuvieri,  996. 

Venosus,  995-998. 

Duplicative  subdivision  of  Cells,  125,  126. 

Duration  of  Cell-life,  134,  135  ;  varying,  of  dif- 
ferent parts  of  the  fabric,  549,  550;  inverse 
ratio  of,  to  vital  activity,  134. 

Duty,  idea  of,  814-816. 

Duverney's  glands,  962. 

Dyslysin,  95. 


E. 


Ear,  general  action  of,  894 ;  comparative  struc- 
ture of,  894-899;    distribution    of  auditory 
nerve  in,   894-896 ;   acoustic   principles  of, 
896-899  ;  uses  of,  middle,  899-901 ;  internal, 
901,  902;    external,  906;   development  of, 
1010,  1011  ;  (see  Hearing). 
Earthy  Phosphates  in  Urine,  606,  607. 
Ectopia  Cordis,case  of,  478. 
Efferent  nerve-fibres,  651,  654. 
Egg-shell,  fibrous  tissue  of,  62. 
Eighth  Pair  of  Nerves;  see  Pneumogastric. 
Ejaculatio  Seminis,  956 ;  its  independence  of 

sensation,  695,  696,  698. 
Elastic  Fibrous  tissue,  224-226. 
Elasticity  of  Arteries,  486. 
Electricity,  relation   of,  to  nerve-force,  356- 
358;  influence  of  currents  of,  on  muscles, 
318,  319;  on  rigor  mortis,  333;  on  move- 
ments of  heart,  469  ;    on    contraction    ol 
arteries,  484  ;  connection  of,  with  nutri- 
tive and  secretory  operations,  634. 


Evolution  of,  in  living  body,  633,  634,  640  ; 
disturbance  of,  in  muscular  contraction, 
329,  636-637;  muscular  current  of,  634- 
637;  nervous  current  of,  637-639;  peculiar 
cases  of,  640. 

Electro-biological  state,  797-799. 
Electro-tonic  state  of  nerves,  638,  639. 

Elliptical  skull,  1034,  1035. 

Embryo-cell,  988. 

Embryo,  general  development  of,  at  different 
ages,  1012,  1013  (see  Development  of  Em- 
bryo). 

Embryonic  life,  peculiar  condition  of,  148, 149. 
Emotions,  composite  nature  of,  761,  762  ;  their 
direct  action  on  the  automatic  apparatus, 
763-764  ;  their  influence  on  the  intellectual 
processes,  765 ;  their  expenditure  in  bodily 
change,  765,  766  ;  their  perverted  action  in* 
hysteria,  767,  845,846;  in  insanity,  766  note, 
806-809;  their  influence  on  volitional  move- 
ments, 768,  769  ;  their  unconscious  action, 
791,  792  ;  influence  of,  on  stammering,  940  ; 
on  heart's  action,  474. 

Emulsification  of  fat  in  duodenum,  429. 

Enamel,  structure  of,  285;  composition  of, 
286  ;  development  of,  288-290. 

Encyste'd  embryos,  558. 

Epencephalon,  990,  1009. 

Encephalon  of  Man,  its  proportion  to  Spinal 
Cord,  746  ;  supply  of  blood  to,  747  (see  Ce- 
rebrum, Cerebellum,  and  Medulla  Oblongata). 

Epidermis,  structure  of,  246-248;  develop- 
ment of,  248;  pigment-cells  in,  248-250; 
appendages  to,  250-256. 

Epilepsy,  pathology  of,  841,  842;  artificial, 
induced  by  irritation  of  mesocephale,  710. 

Epithelium,  forms  of,  235,  236;  ciliated,  236- 
237;  renewal  of,  244. 

Erectile  tissues,  peculiar  structure  of,  501. 

Erect  vision,  883. 

Ethiopian  Nations,  1047-1050. 

European  Nations,  1042-1046. 

Euskarian  language,  1043,  1044. 

Eustachian  Tube,  uses  of,  901. 

Valve,  uses  of,  997,  998. 

Exanthemata,  state  of  blood  in,  187,  567,  568. 

Excito-motor  actions,  349,  373,  398,  671-676. 

Excrement itious  substances,  80. 

EXCRETION,  general  nature  of,  367-368,  575; 
sources  of  demand  for,  367,  577,  578;  sta- 
tics of,  576,  577;  complementary  relation 
of  different  modes  of,  578  ;  vicarious  forms 
of,  579,  580. 

Exhalation  from  Lungs,  532,  533  ;  from  Skin, 
see  Cutaneous  Transpiration. 

Exhausting  diseases,  death  by,  causes  of,  624, 
1055,  1056. 

Expectant  Attention,  production  of  movements 
by,  920-924;  production  of  organic  changes 
by,  947,  948. 

Experiments  on  Nerves,  value  of,  655-657. 

Expiratory  movements,  511;  force  required 
for,  512. 

External  Ear,  905,  906. 

Externality,  elementary  notion  of,  757,  758. 

Extra-uterine  fetation,  968. 

Extractive  Mutters  of  Blood,  173. 

of  Urine,  91,  92,  603,  605. 

Exudations,  inflammatory,  569-572. 

Exuviation  of  effete  tissues,  552. 

Eye,  optical  structure  of,  874-877;  adaptation 
of,  to  distances,  876 ;  defects  in  refractive 


INDEX   OF    SUBJECTS. 


1079 


power  of,  877;  nervous  organization  of,  878, 
879;  development  of,  1010  (see  Vision). 
Eyes,  convergence   of,   876,    888;    consenta- 
neous movements  of,  912-917. 


F. 


Facial  Angle  of  Man  and  Quadrumana,  47. 

Nerve,  685;  its  connection  with  sense  of 

taste,  718. 

Faeces,  composition  of,  435-438;  expulsion  of, 
410,411. 

Faith,  curative  powers  of,  947. 

Fakeers,  Indian,  simulated  death  of,  1058. 

Fallopian  Tubes,  passage  of  spermatozoa 
through,  962,  963  ;  passage  of  ova  through, 
968;  formation  of  chorion  in,  971. 

False  Joints,  232. 

Falsetto  voice,  933-934. 

Faroe  Islanders,  food  of,  388. 

Fat ;  see  Adipose  Tissue. 

Fat-Cells,  256,257. 

Fats,  saponiriable,  71  ;  their  production  in  the 
body,  71,72;  their  presence  in  its  tissues 
and  fluids,  72,  73;  their  calorifying  power, 
73,  74 ;  their  use  in  assimilation  and  histo- 
genesis,  73,  74. 

non-saponifiable,  74-75. 

Fatty  Components  of  the  Human  body,  69. 

Degeneration,  71,559;  of  uterus,  after  par- 
turition, 553,  980;  of  biliary  cells,  589,  590. 

Matters   of  Blood,    173;    variations   in 

amount  of,  in   disease,   189,    190;  uses  of, 
207,  208. 

Fecundation,  nature  of,  968,  969  ;  seat  of,  967, 
968. 

Female,  peculiarities  of  constitution  of,  1017, 
1018;  pulse  of,  481;  respiration  of,  526, 
527;  relative  viability  of,  1015;  relative 
height  and  weight  of,  1016,  1017;  function 
of,  in  generation,  see  GENERATION. 

Fenestra  ovalis  and  rotunda,  901,  902. 

Ferment  of  saliva,  412;   of  gastric  fluid,  427. 

Fermented  liquors,  influence  of,  on  the  system, 
389,  390. 

Ferments,  operation  of,  in  the  body,  54,  116, 
136,  191  (see  Zymotic  Poisons). 

Fever,  state  of  blood  in,  186,  187  ;  mortality 
from,  542,  543. 

Fibre,  Muscular,  striated,  303-309;  non-stri- 
ated, 309,  310  (see  Muscular  Fibre). 

,  Nervous,  tubular,  336,  337;  gelatinous, 

337. 

Fibres,  simple,  their  formation,  138,  139. 

Fibrillae  of  Muscle,  ultimate  structure  of,  205, 
206. 

Fibrillation  of  Fibrin,  60;  circumstances  af- 
fecting it,  61. 

Fibrin,  distinctive  characters  of,  58;  chemical 
composition  of,  59;  reduction  of,  to  albu- 
minous condition,  60;  fibrillation  of,  60; 
circumstances  affecting  it,  61 ;  vital  nature  of 
the  process,  62  ;  probable  use  of,  in  the  eco- 
nomy, 63;  increase  of^  by  oxygenation,  179. 

of  Blood,  variations  of  in  disease,  185- 

187  ;  its  share  in  producing  coagulation,  193  ; 
its  uses,  201-202;   larger  proportion  of,  in 
arterial  blood,  178;  increase  of,  in  passing 
through  liver,  183. 

of  Chyle,  451,  452  ;  increase  of,  in  transit 

towards  sanguiferous  system,  453,  454. 


Fibrin  of  Lymph,  451,  454. 

Fibro- Car  triage,  260,  261. 

Fibro- Cellular  Membranes,  229,  230. 

Fibrous  tissues,  224  ;  white,  224;  yellow,  225; 
areolar,  226  ;  development  and  reparation  of, 
227-229;  gelatinous  composition  of,  63,  113. 

Fibrous  Membranes,  structure  of,  224. 

Fifth  Pair  of  Nerves,  general  functions  of,  683- 
685;  lingual  branch  of,  687,  688;  its  action 
in  mastication,  400;  influence  of,  on  smell. 
872. 

Fins,  race  of,  1045. 

Fishes,  brain  of,  647;  spinal  cord  of,  663. 

Flowering  Plants,  generation  in,  950. 

Fluids,  absorption  of,  from  stomach,  442,  443; 
from  intestinal  walls,  438-445;  from  general 
surface,  445-448;  by  lacteals,  439-442 ;  by 
lymphatics,  448;  by  bloodvessels,  442-445, 
447,  448. 

Fluoride  of  Calcium,  its  presence  in  the  body. 
104. 

Flute-pipes,  action  of,  929. 

flying-fish,  spinal  cord  of,  663. 

Foetus,  circulation  in,  992-999;  development 
of  organs  in  (see  Development  of  Embryo]  ; 
general  condition  of,  at  different  ages,  1012, 
1013  ;  size  and  weight  of,  at  birth,  1013, 1014. 

Follicles  of  Glands,  239-241  ;  of  Mucous  mem- 
branes, 232,  239  ;  of  Lieberkuhn,  239. 

Food,  classification  of  components  of,  375;  sac- 
charine and  oleaginous  constituents  of,  376, 
381,  382;  albuminous  constituents,  376,  381; 
gelatinous  constituents  of,  377  ;  proportions 
of  carbon  and  nitrogen  in  different  articles 
of,  378,  379;  most  economical  combinations 
of,  379,  380;  relative  value  of  animal  and 
vegetable,  379-381;  general  conclusions  re- 
garding its  composition,  381-383;  quantity 
of,  needed  by  Man,  384-386;  importance  of 
purity  of,  387,  388  ;  prehension  and  ingestion 
of,  397;  relative  digestibility  of  different 
kinds  of,  424,  426. 

Force,  to  be  considered  as  an  expression  of 
Will,  37,  773,  787;  relation  of,  to  mental 
action,  772-775. 

,  Vital,  119;  its  manifestations,  141;  its 

relations  to  Physical  forces,  142,  146;  vari- 
ations in  degree  of,  with  age,  148-153. 

Form,  mode  of  acquiring  a  knowledge  of,  by 
touch,  859;  by  sight,  882-887. 

Formative  power  of  individual  parts,  546,  551; 
excess  of,  in  hypertrophy,  555-558 ;  defi- 
ciency of,  in  atrophy,  559,  560;  manifesta- 
tion of,  in  reparative  process,  560-566; 
greater  energy  of,  in  lower  animals  and  in 
early  stage  of  higher,  149,  151,  560,  561  ; 
deficiency  of,  in  inflammation,  566-568. 

Fornix,  746. 

Fourth  Pair  of  Nerves,  functions  of,  685. 

Freckles,  249. 

Free-will,  775  ;  belief  in  our  own,  785. 

Frigorifying  process,  631. 

Functions,  Vital,  359;  Organic,  359,  360;  Ani- 
mal, 360,  361;  their  mutual  relations,  361- 
363. 

Fungous  growths,  573,  574. 


G. 


Gall-bladder,  contraction  of,  432. 
Ganglia,  nervous  structure  of,  334,  335. 


1080 


INDEX   OF   SUBJECTS. 


Ganglia,  Sensory;   see  Sensory  Ganglia. 
Gangrene,  nature  of,  567  ;  spread  of,  572. 
Gases  of  Blood,  179. 
Gastric  Follicles,  414,  416. 
Gastric  Juice,  composition  of,  417-420;  condi- 
tions of  its  secretion,  420-424;   uses  of  in 
digestion,  424-427 ;  amount  of,  secreted,  426. 
Gelatin  ;  see  Glutin. 
Gelatinous  Compounds,  66. 
Gelatinous  nerve-fibres,  337. 
Gelatin  sugar,  67. 
Geldings,  Cerebellum  of,  737,  738. 
GENERATION,  general  nature  of,  370,  948; mode 
of  its  performance  in  Plants,  949-951;  ge- 
neral mode  of  its  performance  in  Animals, 
952;  essentially  consists  in  union  of  con- 
tents of  sperm-cell  and  germ-cell,  949. 
Action  of  Male  in,  951-957;    structure  of 
testes,  951,   952  ;    characters  of  seminal 
fluid,  954;  nature  and  evolution  of  Sperm- 
atozoa, 954-955  ;   essential  importance  of 
Spermatozoa,  954,  955,  969  ;  share  of,  in 
coition,  956. 

Action  of  Female  in,  957-985  ;  structure  of 
ovum,  957;  evolution  of  ovum,  958;  matu- 
ration and  discharge  of  ovum,  959;  period 
of  puberty,  959,  960;  menstrual  discharge, 
960-962;  share  of,  in  coition,  962,963; 
expulsion  of  ova  from  Graafian  vesicle, 
963;  formation  of  corpus  luteum,  963-966; 
discharge  of  ova  independent  of  coitus, 
967,  968;  fecundation  of  ovum,  968,  969; 
changes  in  germinal  vesicle  and  germinal 
spot,  969;  nature  of  fecundating  process, 
969-971;  formation  of  chorion,  971,  972; 
of  decidua,  972-974;  of  villi  of  chorion, 
974,975;  of  placenta,  974-978;  placen- 
tal  murmur,  978;  changes  in  mammas, 
978  ;  quickening,  979  ;  parturition,  act  of, 
979,  980 ;  period  of,  980-985 ;  superfceta- 
tion,  985  (see  Lactation). 
Embryonic  Development;  see  Development 

of  Embryo. 

Generative  apparatus,  of  Male,  951,  952;    of 
Female,   957-959;    development  of,   1002- 
1005;  see  Testes,  Ovaria,  and  Uterus. 
Germ-Cell,  of  Plants,  949,  950;   of  Man,  958. 
Germinal  Capacity,  of  embryo,  148,  149;  pro- 
gressive reduction  of,  with  advance  of  life, 
150-153. 

Membrane,  989,  990. 

Vesicle  and  Spot,  958;   changes  in,  at 

maturation  of  ova,  969. 
Gestation ;  see  Pregnancy. 
Glands,  elementary  structure  of,  239-241. 

of  Absorbent  System,  450,  451. 

Vascular  or  Ductless,  456. 

Globules,  of  Blood  ;  see  Blood-Corpuscles. 

of  Chyle,  457. 

Globulin,  chemical  composition    and   proper- 
ties of,  58. 

Glosso-Pharyngeal    Nerve,  functions   of,  686, 
687;  its  instrumentality  in  deglutition,  402, 
403  ;  in  sense  of  taste,  687,  688. 
Glottis,  regulation  of  aperture  of,  928,  929. 
Glucose,  75,76. 

Glutin,  chemical  composition   and   properties 
of,  66,67;   uses  of,  in  the  body,  68;  pre- 
sence of,  in  bone,  270,  271. 
Gluttony,  feats  of,  386. 
Glycerine,  70,  71. 
Glycine,  67,  87,95. 


Glycocholic  Acid,  95. 
Go'ugh,  case  of,  862. 
Graafian  vesicle  ;  see  Ovisac. 
Granulation,  process  of,  564-566. 
Granules,  development  of,  into  cells,  128. 
Gray  Fibres  of  Nervous  System,  337. 

—  Matter   of  Nervous    System,  338,  339  ; 

distribution  of,  in  Spinal  Cord,  661,  662  ;  in 

Cerebrum,  741,  742. 
Growth,  a  source  of  demand   for   food,  547; 

excess  and  deficiency  of,  547 ;  its  difference 

from  development,  548,  549. 
Guanine,  86  note,  93. 
Guiding  sensations,  necessity  of,  in   so-called 

"  odylic?'  movements,  921,  922;  essential  to 

voluntary  movements,  722-728. 
Gustative  Sense  ;  see  Taste. 
Gustatory  Ganglia,  703. 

—  Nerves,  687,  688,  718,  719. 


II . 


Habits,  influence  of,  in  determining  muscular 
movements,  699,  721  ;  in  determining  suc- 
cession of  thoughts,  769,  788,812-814;  in 
producing  access  of  sleep,  822  ;  in  terminat- 
ing sleep,  823  ;    in   modifying  intensity  of 
sensations,  850,  851. 
Hachisch,  delirium  of,  803-805. 
Hcemadynamometer,  479. 
Hamatin,  chemical  composition  and  proper- 
ties of,  65. 

Haematococcus,  multiplication  of  cells  of,  125. 
Haematoidin,  66. 

Hair,  structure  of,  251-254  ;  development  of, 
254-256;  production  of,  in  cysts,  558 ;  va- 
riation of,  in  different  races,  1031. 
Hallucinations  of  insanity,  809,  810. 
Hamilton,  Dr.  R.,  case  of,  797  note. 
Hand,  peculiar  to  Man,  41. 
Harmony  of  movements  of  eyeballs,  914. 
Haversian  Canals  of  Bone,  267-269. 
Healing  of  wounds,  561-566;  see  Reparation 

of  injuries. 

Hearing,  physical  conditions  of,  894-899. 
Organ  of,  essential  structure  of,  894,  896  ; 
its  adaptation  to  laws  of  propagation  of 
sound,  897-899;  structure  and  functions 
of  membrana  tympani,  899,  901  ;  uses  of 
tympanic  cavity,  and  Eustachian  tube, 
901  ;  chain  of  bones,  and  fenestra  ovalis, 
901,  902  ;  labyrinth,  903  ;  external  ear  and 
meatus,  905,  906 ;  transmission  of  vibra- 
tions through  bones  of  head,  906. 
Sense  of,  907-909  ;  tones  produced  by  suc- 
cession of  impulses,  907;  estimate  of  in- 
tensity, direction,  and  distance  of  sounds, 
907,  908;  rapidity  of  perception  by,  com- 
pared with  vision,  908;  uses  of,  in  regu- 
lating voice,  726,  727,  908. 
Heart,  muscular  fibre  of,  310;  concentric  hy- 
pertrophy of,  334  ;  irritability  of,  468. 
Rhythmical  movements  of,  468-472;  influ- 
ence of  Nervous  system  on,  470,  471  ; 
disturbance  of,  by  attention  to  them,  920. 
Successive  actions  of,  472,  473;  course  of 
blood  through,  474;  difference  of  two 
sides  of,  475,476;  sounds  of,  476-477; 
rate  of  propulsion  of  blood  by,  478,  479 ; 
force  of  propulsion  of,  479,  480 ;  number 
of  pulsations  of,  481,  482. 


INDEX   OF   SUBJECTS. 


1081 


First  development  of,  992;  subsequent 
changes  in,  995-999. 

Heat,  Influence  of,  on  Vital  action,  143-145, 
614,  615. 

Animal,  sources  of  its  production,  73,  80, 

145,  146,  621-629;  standard  of,  in  Man, 
616;  in  infants,  616;  in  aged  subjects,  616; 
diurnal  variation  of,  617;  development  of, 
in  muscular  contraction,  329;  increase  of, 
by  exercise,  617 ;  in  inflammation,  568;  by 
ingestion  of  food,  617;  influence  of  external 
temperature  on,  618;  influence  of  disease 
on,  618,  619;  liberation  of,  after  death,  619; 
dependence  of,  on  oxidation  of  hydrocarbon, 
621-625;  loss  of,  the  cause  of  death  by 
starvation  and  exhausting  diseases,  624  ;  par- 
tial dependence  of,  on  cutaneous  respira- 
tion, 625;  influence  of  nervous  system  on, 
626-629  ;  inferior  power  of  generating  in 
infants,  629-631  ;  reduction  of,  by  evapora- 
tion from  cutaneous  surface,  631. 

External,  power  of  enduring,   619-621  ; 

influence  of,  on   muscular  tonicity,  331 ;  on 
temperature    of   body,    618;    effect   or,    on 
transpiration,  612,  613. 

Sexual,  of  lower   animals,  analogous  to 

menstruation,  960,  961. 

Height  at  different  ages,  1016,  1017. 

Hemorrhage,  influence  of,  on  composition  of 
Blood,  178. 

Hemorrhagic  diathesis,  state  of  blood  in,  187. 

Hepatic  Artery,  distribution  of,  in  liver,  583, 
584. 

Cells,  589  ;  fatty  degeneration  of,  589. 

— —  Ducts,  distribution  of,  in  liver,  5S5-587. 

Vein,  blood  of,  183,  184;  distribution  of, 

in  liver,  5S3,  585. 

Hereditary  transmission  of  psychical  powers, 
817  ;  of  psychical  peculiarities,  1037. 

Hermaphrodism,  1004,  1005. 

Heterologous  growths,  573. 

Hiccup,  act  of,  518. 

Hindostan,  languages  and  people  of,  1046, 
1047. 

Hippuric  Acid,  composition  and  properties  of, 
87,  88 ;  sources  of  its  production  in  the 
living  body,  87,  88  ;  its  presence  in  human 
urine,  603. 

Histogenetic  Compounds,  51,  112;  appropria- 
tion of,  by  the  tissues,  140,  153,  154. 

Homicidal  Insanity ,  cases  of,  808  note,  809  note. 

Hooping-cough,  846. 

Horny  matter,  composition  of,  248. 

Horses,  cerebellum  of,  737-738;  experiments 
on  spinal  cord  of,  665. 

Hottentot  race,  1049,  1050. 

Hull,  cholera  at,  542  ;  fever  at,  542. 

Humblebee,  heat  evolved  by,  622. 

Hunger,  indicates  necessity  for  aliment,  364, 
382;  sources  of  sense  of,  391,  392. 

Hunting,  effects  of,  on  rigor  mortis,  333. 

Hybrid  races,  970  ;  fertility  of,  1039. 

Hybridity  between  species,  limits  of,  1039. 

Hydrochloric  acid,  its  presence  in  the  body, 
105;  the  principal  acid  of  gastric  juice, 
418,  419. 

Hydrogen,  elimination  of,  by  respiratory  pro- 
cess, 532,  533. 

— — ,  respiration  of,  531. 

Hydrophobia,  pathology  of,  727,844;  excite- 
ment of  its  paroxysm  by  sensations,  720. 

Hypertrophy,  547,   555;  conditions   of,  555- 


556;  shown  in  production  of  tumors,  556; 
in  supernumerary  parts,  557,  558;  modifi- 
cation of,  in  malignant  tumors,  558. 

Hypnotism,  phenomena  of,  801,  802. 

Hypochondriasis,  state  of,  947. 

Hypoglossal  Nerve,  functions  of,  691,  692. 

Hypoxanthine,  87. 

Hysteria,  emotional  perversion  in,  767,  768  ; 
pathology  of,  844-846  ;  remarkable  case  of, 
844  note. 

Hysterical  ischuria,  579. 


I. 


lago,  character  of,  818. 

Iceland,  high  rate  of  mortality  in,  544,  545. 

Ideas,  formation  of,  by  the  instrumentality  of 
the  Cerebrum,  755,756;  sensational,  785; 
intellectual,  785. 

Ideational  consciousness,  757  ;  actions  prompt- 
ed by,  799,  833,  922. 

Identification,  mental  tendency  to,  777. 

Ideo-motor  actions,  799,  922. 

Idiocy,  predominance  of  instinct  in,  752;  re- 
markable cases  of,  363  note,  766  note,  813 
note;  causes  of,  817,  970,  971. 

Imagination,  faculty  of,  792. 

Imitation,  tendency  to,  809  note. 

Impressions  on  Nervous  Centres,  ordinary  ac- 
tion of,  648  ;  reflex  movements  excited  by, 
648,  649. 

Impulsive  insanity,  808,  809. 

Inanition,  M.  Chossat's  experiments  on,  393, 
394,  623-624. 

Incontinence  of  Urine,  702,  846. 

India,  languages  and  population  of,  1046,  1047. 

Indo-European  race,  1043-1046. 

Induction,  mental  tendency  to,  777. 

Infancy,  peculiar  attributes  of,  150. 

Infants,  temperature  of,  616;  imperfect  heat- 
producing  power  of,  629-630;  size  and 
weight  of,  1013,  1014;  early  viability  of, 
984,985;  relative  viability  of,  in  male  and 
female,  1015,  1016. 

Inflammation,  essential  nature  of,  566-568; 
relations  of,  to  hypertrophy  and  atrophy, 
566;  causes  of,  567,  568;  phenomena  of, 
568-569;  state  of  the  blood  in,  185-190, 
569;  characteristic  effusions  in,  569-572; 
unhealthy  forms  of,  571  ;  effects  of,  in  tu- 
bercular subjects,  572,  573. 

Ingestion  of  food,  397. 

Inorganic  Constituents  of  Blood,  174  ;  their 
uses,  208,  209. 

Inosic  Acid,  90. 

Inosite,  or  Muscle-Sugar,  77. 

Insalivation,  412-414. 

Insanity,  phenomena  of,  806-810;  from  intel- 
lectual perversion  or  deficiency,  806,  807  ; 
emotional  disorder  or  moral  insanity,  807, 
SOS;  impulsive,  808,  809;  delusions  of, 
809,  810 ;  pathology  of,  754,  834,  835. 

Insects,  heat  evolved  by,  622;  instinctive  ac- 
tions of,  642,  643,  748-749. 

Inspiration,  causes  of  first,  515. 

Inspiratory  movements,  511;  force  required 
for,  512. 

Instinctive  actions,  642,  643  ;  relations  of,  to 
Intelligential,  748-749. 

Intellectual  operations,  775-793;  their  sub- 
ordination to  the  Will,  793-796. 


1082 


INDEX   OF    SUBJECTS. 


Intelligence,  nature  of,  as  opposed  to  Instinct, 
749,  750;  degree  of,  conformable  to  size 
and  development  of  Cerebrum,  750-754. 

Interlobular  veins  of  liver,  584. 

Internal  senses,  nerves  of,  728,  756. 

Intestinal  Digestion  ;  see  DIGESTION. 

Fluid,  428,  429,  432,  433. 

Intestines,  peristaltic  movements  of,  409-410; 
small,  passage  of  food  through,  428-435  ; 
large,  passage  of  food  through,  435  ;  glan- 
dulae  of,  239-241,  432-435;  secretions  of, 
429-435;  villi  of,  239,  439-442. 

Intralobular  veins  of  liver,  584. 

Intuitive  Perceptions,  758-761. 

Invertebrata,  their  nervous  system,  automatic 
character  of,  642,  644. 

Iris,  movements  of;  see  Pupil. 

Iron,  a  constituent  of  the  human  body,  109  ; 
presence  of,  in  red  corpuscles,  160;  admi- 
nistration of,  in  chlorosis,  188. 

Irritability  of  Arteries,  483,  484. 

of  Heart,  468  ;  see  Heart. 

of  Muscles,  317;  see  Muscular  Fibre. 


J. 


Jacob,  membrane  of,  878. 

Jails,  Indian,  high  rate  of  mortality  in,  544  ; 
English,  cholera  in,  539-541. 

Jaundice,  passage  of  biliary  coloring  matter 
into  the  tissues  and  secretions  in,  580  ;  dif- 
ferent forms  of,  592,  593. 

Jewish  Females,  period  of  conception  in,  968 
note. 

Nation,  1045;  varied  hues  of,  1031. 

Juice  of  Flesh,  79,  89,  90. 


K. 


Kaffre  race,  1049. 

Kidney,  structure  of,  594-599;  tubuli  uriniferi 
of,  595-597;  circulation  in,  597-599;  Cor- 
pora Malpighiana  of,  595-599;  secreting 
cells  of,  595;  development  of,  1001,  1002; 
elimination  of  water  by,  598,  599  ;  secreting 
action  of,  599-609 ;  excretory  function  of, 
609-611  (see  Urine). 

Kurrachee,  cholera  at,  540,  541. 

Kymographion,  490. 


Labyrinth  of  Ear,  functions  of,  903. 

Lachrymal  secretion,  influence  of  nervous  sys- 
tem on, 942. 

Lactation,  1021,  1025;  see  Mammary  Gland 
and  Milk. 

Lacteals,  origin  of,  in  villi,  439-441;  absorp- 
tion of  by,  442-445. 

Lactic  Acid,  its  composition  and  properties, 
78,  79;  its  presence  in  the  fluids  of  the 
body,  79,  80  ;  its  origin  and  destination,  80 ; 
its  occasional  presence  in  urine,  603,  604. 

Lacunae  of  Bone,  269  ;  formation  of,  276,  277. 

Lamina  spiralis,  896. 

Laminae  dorsales,  990. 

Languages  of  different  races,  essential  con- 
formity in,  1041,  1042;  Indo-Germanic, 
1043;  Celtic,  1043;  Euskarian,  1043;  Syro- 


Arabian,  1044,  1047,  1048;  Mongolian, 
1045;  Seriform,  1046;  Tamulian,  1046; 
Hindoo,  1046;  Sanskritic,  1043,  1046;  Ne- 
gro, 1048;  Kaffre,  1049;  Hottentot,  1049  ; 
Bushman,  1050;  American,  1051;  Malayo- 
Polynesian,  1052;  Negrito,  1053. 

Landau,  effects  of  siege  of,  1011. 

Lanugo  of  foetus,  255. 

Lapps,  race  of,  1045. 

Laryngeal  nerves,  their  respective  actions, 
517,518. 

Larynx,  structure  of,  924,  925;  actions  of, 
517,518,927-929;  their  instrumentality  in 
the  production  of  sounds,  929-932  ;  theory 
of  the  voice,  932,  933  ;  falsetto  voice,  933, 
934 ;  automatic  nature  of  movements  of, 
934,  935  ;  their  dependence  on  guiding  sen- 
sations, 722,  723,  908;  spasmodic  closure 
of,  846. 

Laughing,  act  of,  518. 

Law  of  Nature,  meaning  of  the  term,  33. 

Lead,  occasional  presence  of,  in  the  body, 
111;  toxic  action  of,  214. 

Length  of  Fretus  at  different  ages,  1012-1013. 

Leucine,  derived  from  protein  compounds,  54; 
from  gelatin,  67. 

Leucocythsemia,  188. 

LIFE,  or  Vital  Activity,  dependent  on  mate- 
rial conditions  and  dynamical  agency,  119, 
120;  relation  of,  to  chemical  and  physical 
forces,  116-118,  126-137,  140-146;  varying 
duration  of,  in  individual  parts,  see  Duration. 

Life  of  a  Cell,  history  of,  124-135. 

of  Man,  characters  of  principal   epochs 

of,  148-153. 

Ligaments,  structure  of,  224;  elastic,  226. 

Light,  Influence  of,  on  Vital  action,  143;  on 
pigment-cells,  249,  250. 

Evolution  of,  in  human  subject,  632,  633  ; 

from  urine,  sweat,  and  semen,  633. 

Limbs,  nature  and  development  of,  1007. 

Lime,  Carbonate  of,  its  uses  in  the  body,  103 ; 
proportion  of,  in  bone,  271,  272 ;  in  teeth, 
.  286,  287. 

Phosphate  of,  its  uses  in  the  body,  101  ; 

proportion  of,  in  bone,  271,  272 ;  in  teeth, 
286,  287. 

Limits  of  vision,  880. 

Lingual  branch  of  Fifth  pair,  its  participation 
in  sense  of  Taste,  684,  687,  688. 

Liquor  Sanguinis,  157. 

Liver,  structure  of,  581-590  ;  general  plan  of, 
in  lower  animals,  581,  582  ;  in  man,  583  ; 
arrangement  of  bloodvessels  in,  583-585; 
biliary  ducts  in,  585-587  ;  secreting  cells 
in,  586,587,588,  590;  development  of, 
999,  1000  ;  alterations  of,  in  disease,  587- 
590. 

Excretory  function  of,  590,  592,  594;  in 
fetus,  996,  999 ;  formation  of  bile  by, 
59 1-594  (see  Bile}. 

Assimilating  action  of,  183,  184,  449,  450, 
594  ;  production  of  fat  by,  71,  113,  594  ; 
of  sugar  by,  76,  77,  113,  594;  of  fibrin  by, 
183,  184  ;  of  red  corpuscles  by,  167  note. 
Foetal,  depurating  action  of,  996,  997,  999  ; 
development  of,  999,  1000. 

Liver-sugar,  77. 

Locomotion,  movements  of,  automatic  charac- 
ter of,  698-699. 

Loss  of  Blood,  influence  of,  on  Composition  of 
Blood,  178. 


INDEX   OF   SUBJECTS. 


1083 


Luminosity  in  Human  subject,  632,  633. 

Lungs,  structure  of,  504-508  ;  contractility  of 
bronchial  tubes,  510;  elasticity  of,  510; 
force  required  for  their  distension,  510; 
changes  in,  from  section  of  pneumogastric 
nerves,  519-521;  development  of,  999- 
1001. 

Lymph,  composition  and  properties  of,  451, 
452;  corpuscles  of,  453,454. 

,  coagulable,  61;  effusion  of,  in  inflam- 
mation, 570;  conservative  nature  of,  572; 
fibrinous  and  corpuscular  forms  of,  571  ; 
degenerations  of,  571,  572. 

Lymphatics,  absorption  by,  445,  446,  448,  449. 

Lymphatic  Glands,  structure  of,  450,  451. 


M. 


Madder,  effect  of,  on  bones,  280  ;  on  teeth, 
285. 

Magnesia,  Carbonate  of,  its  presence  in  the 
body,  110. 

,  Phosphate  of,  its  uses  in  the  body,  103. 

Magnetism,  Animal  ;  see  Mesmerism. 

Magnetometer,  922  note. 

Magyars,  1045;  assimilation  of,  to  Europeans, 
1042,  1044. 

Maintenance,  a  form  of  nutrition,  551. 

Malayo-Polynesian  races,  1052-1054. 

Male,  rudimentary  uterus  in,  1003;  rudiment- 
ary mammary  gland  in,  1021  ;  lactatiogi  by, 
1022  ;  action  of,  in  generation,  see  GENERA- 
TION. 

Malignant  growths,  558,  574. 

Malpighian  Bodies,  of  Kidney,  595-599;  of 
Spleen,  456,  457. 

Malting,  liberation  of  heat  in,  621. 

Mammalia,  spinal  cord  of,  663;  cerebellum  of, 
731  ;  cerebrum  of,  750,  751. 

Mammary  Gland,  structure  of,  1018-1021 ; 
functional  activity  of,  1021  ;  secretion  of,  in- 
fluence of  mental  emotions  on,  944-945  ;  of 
expectant  attention  on,  947  (see  Milk), 

MAN,  distinctive  characteristics  of,  41  ;  hand 
of,  41 ;  cranium  of,  42,  46  ;  position  of  face 
of,  42  ;  vertebral  column  of,  43  ;  lower  ex- 
tremities of,  44;  facial  angle  of,  47;  myology 
of,  47 ;  visceral  apparatus  of,  48 ;  brain  of, 
48  ;  subordination  of  senses  to  intelligence 
of,  48;  peculiar  adaptability  of,  49;  slow 
growth  of,  49;  mental  endowments  of,  49, 
50;  articulate  speech  of,  50;  capacity  for 
progress  in,  50. 

,  General  Survey  of  Life  of,  148-153;  em- 
bryonic life  of,  149;  childhood  of,  150-151  ; 
adult  age  of,  152 ;  decline  of  life  in,  152, 
153. 

,  Varieties  of,  1029-1054;  see  Color,  Hair, 

Languages,  Pelvis,  Races,  Skull,  and  Va- 
rieties. 

Mania,  phenomena  of,  806. 

Mara,  Mad.,  range  of  voice  of,  920  note. 

Mares,  Cerebellum  of,  737,  738. 

Margaric  Acid,  70. 

Margarin,  69. 

Mastication,  398-400. 

Materialist  doctrine,  its  truths  and  its  errors, 
770-772. 

Matter  and  Mind,  their  differences  and  rela- 
tions, 770-775.  - 

Mauchamp  breed  of  sheep,  1037  note. 


Meatus  auditorius,  905,  906. 
Meconium.  composition  of,  590,  591. 
Medulla  Oblongata,  general  structure  and  rela- 
tions of,  645,  646  ;  particular  account  of,  676 
-683  ;  the  centre  of  nerves  of  respiration  and 
deglutition,  646,  678,  695  (see  Spinal  Axis). 

Medulla  Spinalis;  see  Spinal  Cord. 
Membrana  Granulosa,  957,  964. 

Tympani,  structure  and  functions  of,  899, 

900. 

Membrane,  simp] e  primary,  139,  140;  serous, 
230-232;  synovia),  230-232  ;  mucous,  232- 
235  ;  fibrous,  224  ;  development  of  bone  in, 
272,  273,  280. 

Memory,  connection  of,  with  Association,  776  ; 
nature  of,  781  ;  persistence  of,  782  ;  disloca- 
tion of,  782  (see  Recollection). 

Menstruation,  period  of,  959,  960;  nature  of, 
960-962  ;  persistence  of,  961,  962. 

Mental  action,  its  relation  to  Nervous  action, 
770-775. 

Mesencephalon,  990,  1007. 

Mesmerism,  examination  of  reputed  pheno- 
mena of,  826-829  note;  coma,  826;  somnam- 
bulism, 801,  826;  exaltation  of  senses,  827  ; 
cataleptic  rigidity  of  muscles,  828;  involun- 
tary movements  in,  924  ;  affection  of  organic 
functions,  828,  947  ;  excitement  of  phrenolo- 
gical organs,  828;  clairvoyance,  828;  nature 
of  mesmeric  agency,  828. 

Mesocephale,  effects  of  division  of,  710,  711  ; 
effects  of  electric  irritation  of,  711. 

Metamorphosis,  retrograde,  of  tissues,  113, 
114. 

Metastasis  of  secretion,  578-580. 

Milk,  secretory  apparatus  of,  1018-1021  ;  sup- 
ply of,  1021;  constituents  of,  1022-1024; 
variation  in  their  proportions,  1024,  1025; 
influence  of  mental  states  upon,  942,  944- 
946;  varieties  of,  in  different  animals,  1026, 
1027;  reabsorption  of,  1027 ;  vicarious  se- 
cretion of,  1027;  amount  of,  1028;  passage 
of  medicines,  &c.,  into,  1028. 

,  sugar  of,  1024. 

Milk-teeth,  development  of,  290-294;  order 
of,  295  ;  exuviation  of,  296,  297. 

Milky  serum  of  Blood,  73. 

Milbank  Penitentiary,  scurvy  at,  395,  396; 
cholera  at,  539. 

Mind  and  Matter,  their  differences  and  rela- 
tions, 770-775. 

Mitchell,  James,  case  of,  872. 

Model  Lodging-houses,  low  mortality  in,  543. 

Modelling-process,  563-564. 

Molecular  base  of  chyle,  452. 

death,  1054-1056. 

Mongolian  races,  1045,  1046. 

Monomania,  phenomena  of,  809. 

Monotony,  influence  of,  in  producing  sleep, 
821,  828  note. 

Monstrosities  by  excess,  556,  557  ;  by  inclu- 
sion, 557;  by  arrest  of  development,  548, 
995,  996,  1004,  1008  note. 

Moral  insanity,  807,  80S. 

Morbid  poisons,  216-221. 

Mother,  influence  of  state  of,  on  development 
of  foetus,  970,  971,  1011,  1012;  on  mammarv 
secretion,  944-946. 

Motility,  an  attribute  of  Cells,  130,  131  ;  spon- 
taneous, of  muscles,  319  note;  of  heart,  471 
-472:  of  uterus,  979-981. 

Motive  Powers  to  Human  action,  812,  814. 


1084 


INDEX    OF    SUBJECTS. 


Motor  Linguae,  691,  692. 

Motor  Nerves,  laws  of  transmission  through, 
653,  654. 

of  Orbit,  685,  695. 

Motor  Tract  of  Medulla  Oblongata,  681. 
Movements,  Ciliary,  see  130,  236,  237. 

Muscular,  nature  of,  131,   132;   relation 

of,  te  organism  at  large,  909,  910  ;  voluntary 
and  involuntary,  910;  combination  of,  910; 
symmetry  and  harmony  of,  91 1,  912;  of  eye, 
913-917;  energy  and  Vapidity  of,  917-920; 
influence  of  expectant  attention  on,  920-923 
(see  Muscular  Fibre). 

Mozart,  automatic  action  of  his  creative  pow- 
ers, 789  note. 
Mucous  follicles,  233. 
•         layer  of  germinal  membrane,  989. 
Mucous  Membranes,  structure  of,  232,  233  ;  se- 
cretion of,  233;  general   functions  of,  234, 
235. 

Mucus,  233. 

Multiplication  of  Cells,  125-128. 
Murexide,  85. 
'Muscle-Sugar,  77. 

Muscular  Contraction,  different  modes  of,  317- 
320;    spontaneous,  319   note;    after   death, 
327;   force   of,  328,329;   heat   evolved   in, 
329;    electrical    disturbance   produced    by, 
329,  634-637  (see  Movements,  Muscular). 
Muscular  Current  of  electricity,  634-637. 
Muscular  Fibre,  composition   of,  56,  59,  311  ; 
structure  of,  303-310;  striated,  303-3095 
non-striated,  309,310;  supply  of  vessels 
and  nerves  to,  312,  313;  development  of. 
313,  314  ;  nutrition  of,  315  ;  disintegration 
of,  315-316  ;  effects  of  disuse  of,  316,  317. 
Vital    endowments  of,   317-334;  irritability 
of,  317-320;   its  gradual  departure  after 
death,  320;  its  diminution    by  sedatives, 
321  ;    influence    of  shock    on,  321,  322; 
dependence  of,  upon  arterial   blood,  322, 
323  ;  their  independence  of  nervous  sys- 
tem, 324-326;  peculiar  post-mortem  mani- 
festations of,  326,  327;  Tonicity  of,  330, 
331  ;  rigor  mortis  of,  332-334;   influence 
of  electricity  upon,  333;  spontaneous  rno- 
tility  of,  471-472. 

Muscular  Sense,  importance   of,  in  voluntary 
movements,  722-724  ;  extraordinary  exalta- 
tion of,  in  somnambulism,  &c.,  724;  sugges- 
tion of  ideas  by,  801,  802. 
Muscular  Tension,  influence  of  spinal  cord  on, 

699. 
Myopia,  877. 


N. 


Nails,  structure  of,  250  ;  rate  of  growth  of,  250, 
251. 

Necraemia,  death  by,  1056. 

Negritoes,  or  Pelagian  Negroes,  1052,  1053. 

Negro  races,  color  of,  1031;  hair  of,  1032; 
skull  of,  1032,  1033;  pelvis  of,  1036;  modi- 
fication of,  1035;  geographical  range,  and 
varieties  of,  1047-1049. 

Nerve-Force,  generation  of,  by  cells,  132,  133  ; 
transmission  of,  349-351,  652-654;  its  rela- 
tions to  physical  forces,  351,  352  ;  to  elec- 
tricity, 356,  357  ;  to  animal  heat,  62S,  629; 
to  mental  activity,  770-775  (see  Nervous 
Tissue). 

Nerve-Trunks,  structure  of,  335-337  ;  plexuses 


formed  by,  651,  652;  central  terminations 
of,  339,  340  ;  peripheral  terminations  of, 
312,  313,  341-343  (see  Eye,  Ear,  Papilla?, 
&c.). 

Endowments  of,  349,  651-657 ;  afferent  and 
efferent,  651  ;  use  of  plexuses  of,  651, 
652;  laws  of  transmission  in,  652-654; 
modes  of  determining  their  functions,  654- 
657  ;  by  peripheral  distribution,  654,  655  ; 
by  central  connections,  655,  656;  by  ex- 
periment, 656-657. 

Nervous  Centres,  structure  of,  33S,  339  ;  con- 
nection of,  with  nerve-trunks,  339,  340; 
functional  relations  of,  to  system  in  gene- 
ral, 348-350  ;  principal  organs  of,  in  Man, 
645  ;  Cranio-Spinal  axis,  645,  646;  Spinal 
Cord,  645  ;  Medulla  Oblongata,  645,  646  ; 
Sensory  Ganglia,  646;  Cerebrum,  647  ; 
Cerebellum,  647;  general  course  of  ac- 
tion of,  648-65Q  ;  reflex  operations  of  the 
several  parts,  648-649 ;  subordination  of 
these  to  the  Will,  649,  650. 
Development  of,  999,  1008-1010. 
See  Spinal  Cord,  Medulla  Oblongata,  Sen- 
sory Ganglia,  Cerebellum,  Cerebrum,  and 
Sympathetic. 

Nervous  Current  of  electricity,  637-639. 
NERVOUS  SYSTEM,  general  structure  and  en- 
dowments of,  334  (see  Nervous  Tissue)  ; 
general  functions  of,  371,372;  internun- 
cial  character  of,  349  ;  connection  of,  with 
organs  of  sense,  372,  373;  principal  divi- 
sions of,  374,  375. 

General  arrangement  of,  641-642;  automatic 
character  of,  in  Invertebrata,  642,  643 ; 
distinguished,  in  Vertebrata,  by  Cerebrum, 
and  ministering  to  Intelligence,  644;  sub- 
servience of  general  organism  to,  645. 
Influence  of,  on  Animal  Heat,  625-629  ;  on 
Organic  Functions,  941-948;  shown  in 
effects  of  Emotion  on  Secretions,  942- 
646;  influence  of,  on  Nutrition,  946,  947; 
marked  effect  of  expectant  attention,  947- 
948. 

Nervous  Tissue,  structure  of,  334-343  ;  fibrous, 
335-337;  vesicular,  338,339;  connection  of 
cells  and  fibres,  339,  340;  peripheral  termi- 
nations of  nerve-fibres,  341-343;  composition 
of,  343;  vascular  supply  of,  344,  345  j  nutri- 
tion of,  345 ;  effects  of  disuse  on,  345,  346; 
development  of,  346;  disintegration  of,  354- 
356;  regeneration  of,  347,  348. 
,  functions  of,  348-357;  transmitting  pow- 
er of  nerve-trunks,  349 ;  psychical  relations 
of  centres,  349,  350;  relations  of  nerve-force 
to  other  vital  forces,  350,  351  ;  to  physical 
forces,  351,  352;  to  electricity,  356,  357; 
to  mental  force,  773-775  ;  conditions  of  its 
development,  353-356  ;  necessity  for  oxyge- 
nated blood,  352;  influence  of  contaminated 
blood  on,  353;  disintegration  resulting  from 
its  activity,  354-356. 
Nimes,  prison  at,  396. 
Nitric  acid  of  urine,  607. 

Nitrogen,  proportion  of,  in  different  articles  of 
food,  378;  changes  of,  in  respiration,  531, 
532;  respiration  in,  530,  531. 
Nomadic  races,  peculiarities  of,  1033,  1035. 
Nuclear  fibres,  228. 
Nucleated  blastema,  organization  of,  138,  219, 

287. 
Nuclei,  of  cells,  123;  their  subdivision,  125- 


INDEX   OF   SUBJECTS. 


1085 


127;  free,  137;  their  development  into  nu- 
clear fibres,  228. 

NUTRITION,  general  nature  of,  366,  367,  546, 
547;  dependent  on  pabulum  in  blood,  140, 
211  ;  sources  of  demand  for,  547-551 ;  con- 
dition of  its  performance,  551-554;  inter- 
stitial and  superficial,  552,  553 ;  varying 
activity  of,  554-560;  peculiar  phases  of,  in 
reparation  of  injuries,  562-566;  abnormal 
forms  of,  566-574;  inflammation  and  its  re- 
sults, 566-572  ;  tubercular  formations,  572- 
574;  malignant  growths,  574;  influence  of 
nervous  system  on,  350,  351,  367,  946-948. 


0. 


Oblique  muscles  of  eyeball,  function  of,  913, 

914. 

Oceanic  races,  1051-1054. 
Odoriferous  glandulae,  242,  243. 
Odorous  matter  in  blood,  173. 
Odors,  sensibility  to,  871. 
Odylic  movements,  rationale  of,  921-923. 
(Esophagus,  action  of,  in  deglutition,  404  ;  in 

vomiting,  404. 
Oleaginous  Compounds,  69. 
Oleic  Acid,  70. 
Olein,  69. 

Oleo-phosphoric  acid,  75. 
Olfactory  Ganglia,  702. 

Nerve,  endowments  of,  714;  distribution 

of,  871,  872. 

Olivary  Bodies,  677-682. 

Ganglia,  678. 

Omphalo-mesenteric  vessels,  992,  994,  995. 

Ophthalmic  ganglion,  684. 

Optic  Ganglia,  702 ;   functions  of,  707,  708. 

Nerves,  peculiar    arrangement   of,  716, 

717;  endowments  of,  7 14-7 16;  distribution  of, 
878;  deficient  sensibility  at  entrance  of,  893. 

Thalami,  703-705;  functions  of,  708-711. 

Orang-Outan,  comparison  of,  with  Man,  41-49. 

Orbicularis  muscle,  reflex  action  of,  696,  716. 

Orbit,  motor  nerves  of,  685. 

Order  of  Nature,  33,  34  ;  belief  in,  785. 

Organic  Functions,  359,  360;  their  relations  to 
the  Animal,  361-363. 

Organization,  its  relation  to  Life,  119,  120. 

Oscillations  produced  by  expectant  attention, 
921. 

Osseous  Tissue;  see  Bone. 

Ossification,  intra-membranous,  272,273;  in- 
tra-cartilaginous,  273-276 ;  in  osseous  tu- 
mors, 280. 

Outness,  elementary  notion  of,  757,  758. 

Oval  skull,  1034,  1035. 

Ovarium,  human,  structure  of,  957;  develop- 
ment of,  1002,  1003;  evolution  of  ovisacs 
within,  959;  discharge  of  ova  from,  963-968. 

Overcrowding,  a  powerful  predisposing  cause 
of  zymotic  disease,  539. 

Ovisac,  structure  and  functions  of,  957-959 ; 
formation  of  corpus  luteum  within,  963-968. 

Ovum,  structure  of,  957,  958  ;  evolution  of,  958, 
959  ;  maturation  and  discharge  of,  963-968  ; 
fecundation  of,  968,  969;  first  changes  in, 
969 ;  subsequent  changes  in,  see  Development 
of  Embryo. 

Oxalic  acid  of  urine,  607. 

Oxygen,  respiration  of,  535;  influence  of,  on 
production  of  fibrin,  180. 


P. 


Pacinian  corpuscles,  342,  343. 

Pancreatic  fluid,  composition  of,  428  ;  uses  of, 
in  digestion,  429  ;  amount  of,  secreted,  430. 

Pantheism,  786-788. 

Papillae,  dental,  287;  development  of,  in  fetus, 
290-293. 

of  Mucous  Membranes,  238;  of  Skin,  242, 

858,  859  ;  of  Tongue,  864-868. 

Papuans,  1096. 

Par  Vagum  ;  see  Pneumogastric. 

Paralysis,  pathology  of,  841,  846;  peculiar 
cases  of,  673-674. 

Paraplegia,  pathology  of,  668,  847  ;  peculiar 
cases  of,  672-674. 

Parents,  influence  of  state  of,  on  offspring,  969, 
970. 

Parturition,  act  of,  979,  980 ;  regular  period  and 
causes  of,  980-982;  retarded,  982-983  ;  pre- 
mature, 984,  985. 

Passion,  influence  of,  on  secretion  of  milk,  944, 
945. 

Pathology,  relation  of,  to  Physiology,  38. 

Pelagian-Negro  Races,  1096. 

Pelvis,  variations  in  form  of,  1036. 

Penis,  erectile  tissue  of,  501 ;  function  of,  in 
coition,  956;  development  of,  1004. 

Pepsin,  419. 

Peptones,  427. 

Perception,  nature  of,  758-761. 

Perceptions,  visual,  882,  883. 

Periodical  phenomena,  relation  of,  to  Heat, 
615,  980. 

Periodicity  of  sleep,  819. 

Peristaltic  movements  of  intestines,  309,409; 
influence  of  sympathetic  nerve  on,  409,  410 ; 
influence  of  mental  states  on,  920. 

Persistence  of  sensory  impressions,  gustative, 
870;  olfactive,  873;  visual,  890,  891 ;  audit- 
ory, 908. 

Personal  identity,  consciousness  of,  785. 

Perspiration;  see  Cutaneous  Transpiration. 

Peyer's  Glands,  433,  434. 

Pharynx,  action  of,  in  deglutition,  401-404. 

Phosphate  of  Lime,  uses  of,  in  the  body,  101  ; 
its  importance  In  bones,  271,  272;  in  teeth, 
286,  287. 

Phosphate  ofMagnesia,uses  of,in  the  body,  103. 

Phosphates,  alkaline,  in  Urine,  355. 

Phosphorescence,  cases  of,  in  human  subject, 
533,  632,  633. 

Phosphorized  Fats,  75 ;  their  presence  in  red 
corpuscles  of  blood,  161  ;  in  nervous  tissue, 
344. 

Phosphorus,  a  constituent  of  albumen,  55,  56; 
of  fats  of  brain,  75 ;  its  oxidation  in  the  body, 
355,  606;  its  elimination  from  lungs  as  lumi- 
nous vapor,  533,  632,  633  ;  its  presence  in 
the  urine,  sweat,  and  semen,  92,  632,  633. 

Phosphorus-extractive  of  Urine,  92. 

Photophobia,  716. 

Phrenological  doctrine  of  Cerebellum,  733 
note,  735-740  ;  of  Cerebrum,  750,  780. 

Phthisis,  state  of  blood  in,  186. 

Physical  Forces,  correlation  of,  142  ;  their  re- 
lations to  Vital,  135-137,  142-144. 

Physiology,  object  of  the  Science  of,  33  ;  rela- 
tion of,  to  Pathology,  38. 

Pigment-cells,  248,  249;  influence  of  light  on, 
249,  250 ;  variations  of,  in  different  races, 
1030. 


1086 


INDEX   OF   SUBJECTS. 


Pigmentum  nigrum,  249. 

Pigmentary  matter  of  Urine,  604. 

Pitch  of  voice,  regulation  of,  928. 

Pituitary  membrane,  distribution  of  nerves  in, 
871,872. 

Placenta,  formation  of  maternal  portion  of, 
974-978;  formation  of  foetal  portion  of,  994. 

Placental  sound,  978. 

Plexuses,  nervous,  uses  of,  651,  652. 

Plica  Polonica,  alteration  of  hair  in,  254. 

Pneumogastric  Nerve,  general  distribution  and 
endowments  of,  688-690;  its  instrumentality 
in  deglutition,  403,  404  ;  its  influence  on  se- 
cretion of  gastric  fluid,  422-423  ;  on  move- 
ments of  stomach,  407  ;  on  movements  of 
heart,  469  ;  its  action  as  an  excitor  of  respi- 
ration, 514;  its  motor  powers,  516-517; 
effects  of  section  of,  519-520  ;  influence  of, 
on  larynx,  689,  690. 

Poisons,  influence  of,  on  the  living  body,  136  ; 
elimination  of,  from  the  blood,  214-216  ;  in- 
fluence of,  on  the  Nervous  System ;  see  Toxic 
Influence. 

,  morbid,  their  substantive  existence,  216, 

217  ;  zymotic  conditions  of  their  activity, 
216,  217  ;  course  of  phenomena  in,  219,  220  ; 
alteration  of  blood  by,  220,  221  ;  recovery  of 
blood  from,  221,  222;  materics  morborwn 
generated  within  the  system,  218,  219. 

Polynesian  races,  1052-1054. 

Pons  Tarini,  745. 

Varolii,  effects  of  division  of,  710,  711. 

Portal  blood,  peculiarities  of,  182. 

Portio  Dura  of  Seventh  Pair,  685  (see  Facial 
Nerve). 

Posterior  Columns  of  Spinal  Cord,  structure  of, 
660-662  ;  functions  of,  667-671. 

Pyramids   of  Medulla  Oblongata,  679- 

683. 

Potash,  its  presence  in  the  body,  109;  its  pre- 
dominance in  red  corpuscles  and  in  muscles, 
161. 

Potteries  (Kensington),  mortality  at,  542,  543. 

Pregnancy,  state  of  blood  in,  186;  signs  of, 
978;  usual  term  of,  980-982;  protracted, 
982-983;  abbreviated,  984;  985. 

Presbyopia,  877. 

Pressure  of  blood,  in  heart,  479 ;  in  arteries, 
490. 

Primitive  trace,  990. 

Prognathous  skull,  1032,  1033. 

Projection,  idea  of,  758,  885-887. 

Prosencephalon,  990,  1009. 

Protective  agency  of  Spinal  Cord,  696,  697. 

Protein  Compounds,  general  properties  and  re- 
actions of,  53,  54. 

Protein,  binoxide  and  tritoxide  of,  64,  65. 

Psychical  endowments  of  different  races,  es- 
sential conformity  in,  1040-1041. 

Ptyalin,  412. 

Puberty,  usual  epoch  of,  in  female,  959,  960  ; 
in  male,  955. 

Puerperal  fever,  predisposing  causes  of,  217. 

Pulp,  dentinal,  287;  enamel,  288,  289;  ce- 
mental,  290. 

Pulsations  of  Heart,  causes  of,  468-472. 

Pulse,  Arterial,  487,  488;  rate  of,  at  different 
ages,  481  ;  variations  of,  under  different  cir- 
cumstances, 48 1-482 ;  proportion  of,  to  respi- 
ratory movements,  513. 

,  Respiratory,  498,  499. 

,  Venous,  475. 


Pupil,  movements  of,  697,  716,  877,  880  ;  rela- 
tion of,  to  Third  pair,  685  note  ;  to  Sympa- 
thetic, 830,  831. 

Purkinje,  experiment  of,  893. 

Purpuric  acid,  85. 

Purpurine,  92. 

Pus,  formation  and  characters  of,  571,572; 
influence  of,  on  coagulation  of  Blood,  198. 

Putrefaction,  the  result  of  chemical  agencies, 
135;  may  take  place  even  during  life,  395, 
1054;  evolution  of  light  in,  632;  final  de- 
struction of  body  by,  1059. 

Pyin,  64. 

Pyramidal  bodies  of  Medulla  Oblongata,  677- 
683  ;    anterior,  their  structure  and  connec- 
tions, 677,  681,  683;  posterior,  their  struc- 
ture and  connections,  679-683. 
—  skull,  1033,  1034. 


Q. 

Quadrumana,  comparison  of,  with  Man,  41-49. 
Quagga,  transmission  of  marks  of,  970. 
Quickening,  979. 


R. 


Races  of  Mankind,  Caucasian,  1042-1046; 
Arian.  or  Indo-European,  1043,  1044  ;  Syro- 
Arabian,  1044, 1045 ;  Mongolian,  1045, 1046  ; 
Seriform,  1046;  Hindostanic,  1046,  1047; 
Negro,  1047-1049;  Kaffre,  1049;  Bushman, 
1049,  1050;  American,  1050,  1051  ;  Oceanic, 
1051;  Malayo-Polynesian,  1052;  Pelagian- 
Negro,  1052",  1053. 

Radiating  fibres  of  Cerebrum,  742. 

Radiation  of  Sensations,  854. 

Rapidity  of  muscular  movements,  919. 

Rattlesnake,  secretion  of  poison  of,  continued 
after  death,  941. 

Reasoning  Power,  nature  of,  780. 

Reciprocation  of  sounds,  896-898. 

Reciprocity  of  manifestations  of  Cell-force, 
133. 

Recollection,  power  of,  dependent  on  Asso- 
ciation, 776;  mode  in  which  it  is  exerted, 
783-785. 

Recti  muscles  of  eyeball,  function  of,  913. 

Red  Corpuscles,  see  Blood-Corpuscles,  Red. 

Reeds,  vibrating,  action  of,  930-932. 

Refraction,  laws  of,  873,  874. 

Reflex  actions  of  Nervous  System,  349;  of 
Spinal  Axis,  671-676;  of  Sensory  Ganglia, 
719-722;  of  Cerebrum,  774,  775,  816,  832. 

Regeneration  of  Tissues — of  fibrous  tissues, 
228,  229  ;  of  serous  and  synovial  membranes, 
231  ;  of  mucous  membranes,  234  ;  of  epi- 
thelium, 237;  of  skin,  246;  of  epidermis, 
248;  of  nails,  251  ;  of  hairs,  256  ;  of  crystal- 
line lens,  265  ;  of  bones,  281-282  ;  of  teeth, 
284;  of  capillary  vessels,  301,  302;  of  nerv- 
ous tissue,  347,  348. 

Regeneration  of  lost  parts,  560,  561 ;  see  Re- 
paration. 

Regimen,  influence  of,  on  composition  of 
Blood,  177;  on  system  generally,  380-386. 

Renal  vein,  blood  of,  184. 

Reparation  of  injuries,  560 ;  completeness  of. 
in  lower  animals,  560;  limitations  of,  in 
higher,  560,  561 ;  more  energetic  and  com- 
plete in  embryonic  state  and  in  childhood, 


INDEX   OF   SUBJECTS. 


1087 


149,  150,  151,  560;  not  dependent  on  in- 
flammation, 561,  562  ;  by  immediate  union, 
561  ;  by  adhesion,  562  ;  by  modelling  pro- 
cess, 563-564  ;  by  suppurative  granulation, 
564-566. 

Reproduction,  general  nature  of  the  function, 
370  (see  REGENERATION). 

of  lost  parts,  560,  561  (see  Regeneration 

and  Reparation). 

Resinous  dressing  for  wounds,  564. 

Resistance,  sense  of,  most  generally  diffused, 
852,  859. 

Resonance  of  sounds,  896-898. 

RESPIRATION,  general  nature  of  the  function, 
367,  368;  provisions  for,  502;  sources  of 
demand  for,  502-504. 
Structure   of   apparatus    for,   504-511    (see 

Lungs). 

Movements  of,  51 1  ;  muscular  force  required 
for,  512  ;  rate  and  extent  of,  513  ;  depend- 
ence of,  on  nervous  system,  514-521  ;  in- 
capable of  voluntary  restraint,  516;  dis- 
turbance of,  by  attention  to  them,  920. 
Effects  of,  on  Air,  521-538  (see  Air} ;  on 

Blood,  178-181. 

Consequences  of  Suspension  of,  535-537  ; 
effects  of  deficiency  of,  538-546. 

of  hydrogen,  531  ;  of  nitrogen,  531  ;  of 

oxygen,  179,  535. 

artificial ,  partial  sustenance  of  heat  by,  626. 

Respiratory  Circulation,  peculiarity  of,504,505. 

Pulse,  498,  499. 

Restiform  Bodies,  677-683. 

Ganglia,  678. 

Rete  Mucosum,  247. 

Retina,  structure  of,  879;  deficient  sensibility 
of,  at  entrance  of  optic  nerve,  893 ;  visual 
perception  of,  893;  development  of,  1049. 

Rhythmical  movements  of  heart,  468-472. 

Rigor  mortis,  332-334  ;  influence  of  electricity 
upon,  333. 

of  heart,  478. 

Right,  elementary  notion  of,  786. 

Roots  of  spinal  nerves,  peculiar  endowments 
of,  651,  655,  656;  connections  of,  with  Spi- 
nal Cord,  660-662. 


S. 


Saccharine  Compounds,  75. 

Matter  in  blood,  177. 

Principles  of  Food,  376,  381,  382. 

St.  Kilda,  high  rate   of  infantile   mortality  in, 

545. 

St.  Martin,  case  of,  405,  420,  422,  424-426. 
Saliva,  composition  of,  412-414  ;  uses  of,  413, 

414  ;  influence  of  nervous  system  on  flow  of, 

942,  943. 

Salivary  glands,  412. 
Salt,  common  ;  see  Chloride  of  Sodium. 
Salts  of  Blood,  174;  alteration  of,  in  disease, 

190. 
Sanguification,  process  of,  449-464 ;  share  of 

Liver  in,  450;  share  of  Absorbent  system  in, 

450,  455  ;  share  of  Ductless  Glands"  in,  461- 

464. 

Sanskritic  languages,  1043,  1046. 
Sarcous  elements  of  muscle,  304. 
Saunderson,  case  of,  862. 
Schneiderian  membrane,  distribution  of  nerves 

in,  871,872. 
Scrofulous  constitution,  572. 


Scurvy,  state  of  blood  in,  187,  188. 

— —  at  Miltiank  Penitentiary,  395. 

Sebaceous  Glands,  243,  244. 

Secondarily  automatic  actions,  721,  722. 

SECRETION,  general  nature  of,  368,  574,  575  ; 
effected  by  the  agency  of  cells,  122,  133, 
240  ;  continuance  of,  after  death,  941  ;  influ- 
ence of  nervous  system  on,  350,  360,  361, 
942-948  ;  its  relations  to  excretion,  574,  575 
(see  Excretion);  metastasis  of, 578-580  (see 
Liver,  Kidney,  Bile,  Urine,  &c.). 

Secunderabad,  mortality  in  barracks  at,  543. 

Segmentation  of  vitellus,  988,  989. 

Selecting  power  of  individual  parts,  210. 

Self-control,  power  of,  648,  649  ;  gradual  ac- 
quirement of,  817 ;  loss  of,  in  Insanity,  806— 
810  (see  Will). 

Semicircular  canals,  903. 

Seminal  Animalcules;  see  Spermatozoa. 

Fluid,  characters  of,  954;  secretion  of, 

influenced  by  state  of  feeling,  943  note. 

Semitic  races,  1044,  1045,  1047,  1048. 

Sensation,  definition  of,  848;  dependence  of, 
on  nervous  distribution,  848;  on  capillary 
circulation,  849;  connection  of,  with  pain 
and  pleasure,  849-851  ;  influence  of  habit 
on,  850,  851;  different  forms  of,  851-85?.; 
general  and  special,  851-853;  subjective  at  d 
objective,  853,  854  ;  reference  of,  to  seat  of 
impressions,  855;  influence  of  attention  on, 
855-856;  modification  of,  by  previous  be- 
liefs, 857,  858. 

Sensations,  not  essential  to  reflex  actions  of 
Spinal  Cord,  671-674  ;  but  usually  associated 
with  them,  697,  698;  instrumental  in  reflex 
actions  of  Sensory  Ganglia,  719-722  ;  essen- 
tial to  voluntary  movements,  722-728;  the 
stimuli  to  higher  intellectual  operations,  754, 
755. 

Senses,  exaltation  of,  in  Somnambulism,  827. 

Sensori-motor  actions,  350,  374, 398,  648,  720- 
722. 

Sensorium,  its  special  seat  in  the  sensory 
ganglia,  706. 

Sensory  Ganglia,  general  structure  and  rela- 
tions of,  646,  836-837;  particular  account 
of,  702-706  ;  their  relative  predominance  in 
the  descending  series,  705 ;  constitute  the 
whole  Encephalon  of  lowest 'Fishes  and  In- 
vertebrata,  709  ;  the  probable  seat  of  sensa- 
tion, 706,  707;  reflex  actions  of,  719-720; 
independent  functions  of,  720-722,837-840; 
their  participation  in  voluntary  actions,  722- 
728  ;  pathological  relations  of,  837-842  ;  sus- 
pended action  of,  840-842. 

Sensory  Nerves,  laws  of  transmission  through, 
652,  653. 

Sensory  Tract  of  Medulla  Oblongata,  680,  681. 

Seriform  races,  1046. 

Serolin,  74. 

Serous  Effusions  of  inflammation,  569. 

Serous  Layer  of  germinal  membrane,  989. 

Serous  Membranes,  230-232. 

Serpents,  spinal  cord  of,  663 ;  sympathetic 
system  of,  659. 

Serum  of  Blood,  157,  193;  proportion  of,  to 
Crassamentum,  198  ;  milky,  176,  177. 

of  Serous  Membranes,  231. 

Seventh  Pair  of  Nerves,  portio  dura  of,  685 
(see  Facial  Nerves). 

Sexes,  proportional  number  of,  1014  ;  differ- 
ences in  general  development  of,  1014, 


1088 


INDEX   OF    SUBJECTS. 


1017;  in  viability  of,  1015;  in  constitution 
of,  1017,  1018. 

Sexual  Instinct,  supposed  location  of,  in  Cere- 
bellum, 735-739. 

Organs; see  Generative  Apparatus,  Testes, 

Ovaria,  and  Uterus. 

Secretions,  influence  of  nervous  system 

on,  943. 

sense,  situation  of  ganglionic  centre  of, 

739,  740. 

Sheep,  new  breeds  of,  1037  note. 

Shock,  influence  of,  on  muscular  irritability, 
321,  322;  on  heart,  470. 

Sighing,  act  of,  518. 

Sign-language  of  deaf  and  dumb,  759  note. 

Signs  of  Death,  1058,  1059. 

of  Pregnancy,  978,  979. 

Silica,  its  presence  in  the  body,  105. 

Similarity,  law  of,  777-779. 

Single  vision  with  two  eyes,  884-887. 

Sinus  pocularis,  1003. 

urogenitalis,  1002,  1003. 

Six-fingered  races,  1038. 

Sixth  Pair  of  Nerves,  functions  of,  685,  686. 

Size,  visual  appreciation  of,  888,  889. 

Skeleton  of  Invertebrata,  structure  of,  266. 

Vertebrata,  general  structure  of,  266;  de- 
velopment of,  1005;  varieties  in  conforma- 
tion of,  1032-1037. 

Skin,  structure  of,  241-250;  Cutis  vera,  241, 
242  ;  glandula?  of,  243-245;  papilla?  of,  858, 
859;  nutrition  of,  245,  246;  Epidermis, 
246-248;  pigment-cells,  248-250;  transpi- 
ration from,  611-614. 

Skull  of  Man,  distinctive  peculiarities  of,  42, 
46;  varieties  in  form  of,  1032-1035;  in- 
duced modifications  of,  1035,  1036. 

Sleep,  definition  of,  819  ;  necessity  for,  819, 
820;  periodicity  of,  819;  predisposing  in- 
fluences to,  820 ;  intermediate  stages  be- 
tween sleep  and  waking,  821,  822;  influ- 
ence of  habit  in  inducing,  822,823;  influ- 
ence of  impressions  on  the  sleeper,  823,  824; 
amount  of,  required  by  man,  824-825  ;  cases 
of  absence  and  deficiency  of,  825;  undue 
protraction  of,  826. 

Smell,  sense  of,  871-873  ;  peculiar  objects  of, 
871;  nervous  apparatus  of,  872;  influence 
of  Fifth  pair  on,  872;  uses  of,  872;  im- 
provement of,  873;  special  exaltation  of, 
873  note;  modification  of,  by  habit,  873. 

Smoke,  peculiar  acid  of,  539  note. 

Smooth  Muscular  fibre,  309,  310. 

Sneezing,  act  of,  519. 

Sobbing,  act  of,  518. 

Soda,  carbonate  and  phosphate  of,  their  pre- 
sence and  uses  in  the  body,  107-109. 

Sodium,  chloride  of;  see  Chloride  of  Sodium. 

Solidity,  perception  of,  885-887. 

Somatic  death,  1054-1056. 

Somnambulism,  peculiarity  of  state  of,  800- 
802,811;  exaltation  of  Muscular  sense  in, 
724  ;  exaltation  of  sense  of  smell  in,  873 
note. 

Sound,  laws  of  propngation  of,  896-899. 

Sounds,  Articulate,  935-940. 

of  heart,  476-47$  ;  of  placenta,  978. 

Specific  distinction  between  Human  races,  no 
adequate  grounds  for,  1038-1042. 

Spermatic  cells,  independent  life  of,  124. 

Spermatozoa,  characters  of,  954;  evolution  of, 
954 ;  the  essential  fertilizing  agents,  955. 


Sperm-cell  of  Plants,  949,  950  ;  of  Man,  955. 
Spherical  aberration,  874. 
Sphincters,  action  of,  410,  695. 
Spinal    Accessory    Nerve,    functions   of,   690, 
691  ;  inosculation  of  its  roots  with  Pneumo- 
gastric,  688. 

Spinal  Axis,  functions  of,  695-702,  842.  843; 
its  control  over  the  orifices  of  the  body,  695  ; 
its  relation  to  the  Organic  functions,  695, 
696  ;  its  protective  agency,  696,  697  ;  mor- 
bid excitability  of,  701,  702;  pathological 
relations  of,  842-848. 

Cord,  general  structure  and  relations  of, 

645  ;  comparative  anatomy  of,  663  ;  parti- 
cular account  of,  659-676  ;  anatomy  of,  660- 
667  ;  external  conformation,  and  connection 
of  with  nerves,  660;  internal  structure  of, 
661-667;  different  views  respecting,  664, 
665;  functions  of,  667-676;  conducting 
power  of,  667-671  ;  reflex  actions  of,  671- 
676  ;  their  independence  of  sensation,  671- 
674 ;  their  adaptive  character,  674,  676  ; 
cases  of  injury  of,  672-674  ;  experimental  re- 
searches on,  671,  672,  676  (see  Spinal  Axis). 

Spinal  Nerves,  connections  of,  with  Cord,  660- 
662,  683  ;  general  endowments  of,  650-656. 

Spleen,  structure  of,  456-458 ;  development 
of,  458;  functions  of,  461-464. 

Spiritualist  doctrine,  its  truths  and  its  errors, 
770-772. 

Spitalfields  Workhouse,  fever,  &c.,  at,  543. 

Spontaneous  amputation,  reproduction  of  limbs 
after,  561. 

Splenic  vein,  blood  of,  182,  183,  463. 

Stallions,  Cerebellum  of,  737,  738. 

Stammering,  pathology  and  treatment  of,  939- 
940;  influence  of  emotions  on,  767,  768. 

Starvation,  effects  of,  393,  394;  symptoms  of, 
394,  395;  prolonged,  395,  396;  death  by, 
393-397 ;  consequent  upon  loss  of  heat, 
623-624. 

Steam,  application  of,  to  wounds,  564. 

Stearic  Acid,  70. 

Stearin,  69. 

Stereoscope,  886-887. 

Stomach,  movements  of,  404-408;  secreting 
apparatus  of,  414,  415  ;  villi  of,  416,  417  ; 
gastric  secretion  of,  417-424  (see  Gastric 
Juice)  ;  its  operation  in  Digestion,  424-427; 
effects  of  blows  on,  321. 

Strabismus,  pathology  and  treatment  of,  916, 
917. 

Strangury,  convulsive  action  in,  846. 

Stratum  Malpighii,  247. 

Strength,  feats  of,  918,  919. 

Striated  Muscular  fibre,  303  (see  Muscular 
Fibre). 

Strings,  vibrating,  action  of,  929. 

Strumous  constitution,  572. 

Strychnia,  artificial  tetanus  of,  702,  844. 

Subcutaneous  Wounds,  reparation  of,  228, 
229. 

Subjective  Sensations,  853-858. 

Substantia  gelatinosa  of  Spinal  Cord,  661,  662. 

spongiosa,  661. 

Succession  of  Mental  states,  816,  817  (see 
Trains  of  Thought). 

Succus  entericus,  428,  429,  432,  433. 

Suction,  act  of,  398,  698. 

Sudoriparous  excretion,  composition  of,  612; 
amount  of,  612,  613  ;  vicarious  with  urinary, 
613,614. 


INDEX   OP   SUBJECTS. 


1089 


Sudoriparous  glandulse,  structure  of,  245  ;  num- 
ber of,  611  ;  excretory  action  of,  612-614. 

Swg-ar,  its  composition  and  properties,  75  ;  its 
transformation  in  the  body,  76;  its  produc- 
tion in  the  body,  76,  77. 

Sugar  of  Milk,  1024. 

Suggestion,  influence  of,  in  determining  suc- 
cession of  thought,  788,  796-810. 

Sulphates,  Alkaline,  their  presence  in  the 
body,  110;  in  the  urine,  605,  606. 

Sulphocyanide  of  potassium,  its  presence  in 
the  body,  110;  in  the  saliva,  412 

Sulphur,  an  element  of  protein-compounds, 
63  ;  presence  of,  in  urine,  92;  large  propor- 
tion of,  in  cystine,  93,  94 ;  in  taurine,  96; 
oxidation  of,  in  body,  110. 

Superfetation,  985. 

Supernumerary  parts,  development  of,  557, 
558. 

Suppuration,  571,  572  ;  of  granulation  surface, 
564,  565. 

Suprarenal  bodies,  structure  of,  458,  459  ;  de- 
velopment of,  459,  460;  functions  of,  461, 
462. 

Surgical  fever,  predisposing  causes  of,  217. 

Symmetrical  diseases,  210. 

Sympathetic  System,  general  structure  of,  657, 

658  ;  arrangement  of,  829. 
Cerebro-Spinal  fibres  in,  829,  830;  their  in- 
strumentality in  sensation  and  muscular 
contraction,  830,  831  ;  their  influence  on 
movements  of  intestines,  409,  920;  on 
heart's  action,  469,  470 ;  on  calibre  of 
bloodvessels,  483,  830 ;  on  dilatation  of 
pupil,  831. 

Proper  Fibres  of,  337;  their  probable  func- 
tions, 831 ;  influence  of,  on  animal  heat, 
627. 

Syncope,  state  of  Nervous  Centres  in,  701  ; 
death  by,  1055. 

Synovia,  230. 

Synovial  Membranes,  230-232. 

Syro-Arabian  races,  1044,  1045. 

Systole  of  ventricles,  472,  473  ;  sound  pro- 
duced by,  476,  477  ;  quantity  of  blood  dis- 
charged by,  478,  479;  force  of,  479,480; 
frequency  of,  481,  482. 

Swallowing,  act  of,  401-404. 


T. 


Taliacotian  operation,  regeneration  of  nerve- 
tissue  in,  347. 

Tamulian  language,  1046. 

Taste,  sense  of,  862-870;  peculiar  objects  of, 
862  ;  special  conditions  of,  863  ;  papillae  of, 
864,  865  ;  nerves  of,  686,  687,  862  ;  varying 
acuteness  of,  869  ;  participation  of  smell  in, 
869;  uses  of,  870;  improvement  of,  by  ha- 
bit, 870  ;  cases  of  loss  of,  688,  869. 

Taunton,  cholera  at,  539. 

Taurine,  96. 

Taurocholic  Acid,  95. 

Teeth,  structure  of,  283-287;  composition  of, 
286;  development  of  tissues  of,  287-290; 
evolution  of,  290-295 ;  exuviation  and  re- 
placement of,  296,  297 ;  degeneration  and 
death  of,  554 ;  production  of,  in  cysts,  558. 

Temperature,  Animal  ;  see  Heat. 

Sense  of,  860-861. 

Tendencies  to  thought,  769. 


Tendons,  structure  of,  224  ;  reparation  of,  228; 

attachment  of,  to  muscle,  309. 
j  Tenesmus,  convulsive  action  in,  846. 

Tension,  muscular,  influence  of  Spinal  Cord 
on,  699,  700. 

Testes,  structure  and  secretion  of,  952,  953  ; 
development  of,  1002,  1003. 

Tetanus,  pathology  of,  702,  843,  844. 

Thalami  Optici,  703,  704 ;  functions  of,  708- 
710. 

Thaumatrope,  891. 

Third  Pair  of  Nerves,  functions  of,  685;  its 
influence  on  the  movements  of  the  pupil,  685 
note,  697,  880. 

Third  Ventricle  of  Brain,  1009. 

Thirst,  sense  of,  392,  393. 

Thorax,  movements  of,  in  respiration,  511- 
513. 

Thymus  Gland,  structure  of,  460 ;  develop- 
ment of,  461;  functions  of,  461,  462. 

Thyroid  cartilage,  925 ;  movements  of,  926, 
927. 

Thyroid  Gland,  structure  of,  461  :  develop- 
ment of,  461 ;  functions  of,  461,  462. 

Tissues,  primary,  general  classification  of,  222- 
223. 

Tongue,  papillae  of,  864-868  ;  sensory  nerves 
of,  684,  687,  688 ;  motor  nerves  of,  691, 
693;  partial  paralysis  of,  688,  693. 

Tonicity  of  Muscles,  330,  331 ;  of  Arteries, 
485. 

Touch,  Ganglia  of,  705 ;  Nerves  of,  718;  Sense 
of,  858-862 ;  papilla?  of,  858,  859 ;  varying 
acuteness  of,  859;  knowledge  acquired  by, 
859-861 ;  improvement  of,  861,  862. 

Townsend,  Col.,  case  of,  1058. 

Toxic  diseases,  general  pathology  and  thera- 
peutics of,  215-222. 

Toxic  Influence  on  the  Nervous  System,  pro- 
duction of  delirium  by,  803-805  ;  its  rela- 
tion to  Insanity,  834 ;  to  chorea,  835 ;  to 
coma,  840 ;  to  paralysis,  841,  846;  to  epi- 
lepsy, 841;  to  tetanus,  843;  to  hysteria, 
844  ;  to  convulsive  diseases  generally,  846. 

Trainers'  Diet,  387. 

Trains  of  Thought,  785;  intuitional  nature  of 
some  of  these,  785-788  ;  influence  of  Sug- 
gestion in  exciting  them,  788,  796-810;  in- 
fluence of  the  Will  in  directing  and  control- 
ling them,  788,  789,  793-796,  817-819. 

Trance,  state  of,  1158. 

Transmission  of  nerve-force,  laws  of,  652- 
654;  of  electricity,  653. 

Transudation  of  water  by  Kidneys,  598. 

Trigeminus  or  Trifacial  Nerve,  functions  of, 
683-685;  lingual  branch  of,  687,  688. 

Trismus  nascentium,  mortality  from,  545. 

Tritoxide  of  Protein,  64,  65. 

Troglodytes  gorilla,  skull  of,  46. 

Truth,  elementary  notion  of,  785. 

Tuber  Annulare,  effects  of  division  of,  710,711. 

Cinereum,  745. 

Tubercle,  nature  of,  572-574. 

Tubercula  Quadrigemina,  702;  functions  of, 
707,  708. 

Tubuli  seminiferi,  952. 

uriniferi,  595-597. 

Tumors,  their  relation  to  hypertrophies,  556  ; 
malignant,  558,  574. 

Turkish  nation,  modification  of,  1035,  1045. 

Tympanum,  structure  and  functions  of  mem- 
brane of,  899,  900  ;  cavity  of,  901. 


1090 


INDEX   OF    SUBJECTS. 


Typhoid  fever,  state  of  blood  in,  186,  191. 
Tyrosine,   derived   from    protein-compounds, 


U. 


Ulceration,  nature  of,  567. 

Umbilical  Cord,  structure  of,  994,  995. 

Vesicle,  991,994. 

Vessels,  995-999. 

Unconscious  activity  of  the  Cerebrum,  784, 
790-792. 

Union  of  cut  surfaces,  immediate,  561  ;  by 
adhesion,  562. 

Unity,  Specific,  of  Human  Races,  1038-1042. 

Uraemia,  599,  600. 

Urea,  its  chemical  composition  and  properties, 
81;  sources  of  its  production  in  the  living 
body,  82-83 ;  amount  of,  ordinarily  excreted, 
601,  602;  variations  in  quantity  of,  602- 
605;  presence  of,  in  sweat,  612. 

Uric  Acid,  its  chemical  composition  and  pro- 
perties, 83-86  ;  sources  of  its  production  in 
the  living  body,  86,  87;  amount  of,  ordina- 
rily excreted,  601,  602 ;  variations  in  quan- 
tity of,  86,  602,  605  ;  circumstances  affect- 
ing solubility  of,  85,  86,  607,  608. 

UricxOxide,  92,  93. 

Urinary  Bladder,  contraction  of,  410,  411; 
development  of,  1002,  1004. 

Excretion,  general  purposes  of,  80,  113, 

599;  metastasis  of,  578,  579  ;  see  Urine. 

Organs,  development  of,  1001-1003. 

Urination,  act  of,  410,  411,  695. 

Urine,  secretion  of,  599  ;  excrementitious  cha- 
racter of,  599,  600 ;  physical  properties  of, 
600  ;  quantity  of,  601  ;  specific  gravity  of, 
601;  composition  and  properties  of,  601, 
602;  differences  of,  with  age,  602;  indi- 
vidual components  of,  80-93,  602-604;  in- 
fluence of  diet  upon,  604,  605  ;  inorganic 
constituents  of,  605-607 ;  acid  reaction  of, 
607-608;  alkaline  reaction  of,  608,  609; 
eliminating  agency  of,  609,  610;  influence 
of  diuretics  on,  609,  610  ;  incontinence  of, 
702,  846. 

Urine-Pigment,  92. 

Uro-erythrine,  92. 

Uro-glaucin,  92. 

Uroxanthin,  91. 

Uterus,  muscular  substance  of,  310.  318;  de- 
velopment of,  during  pregnancy,  978  ;  em- 
bryonic development  of,  1003;  inherent 
motility  of,  130-132;  action  of,  in  parturi- 
tion, 979,  980  ;  reflex  action  of,  979  ;  subse- 
quent fatty  degeneration  of,  553,  980  note; 
rudimentary,  of  male,  1003. 


Vagus  Nerve  ;  see  Pneumogastric. 

Valves  of  Heart,  475;  sounds  produced  by 
tension  of,  476,  477. 

Vapor,  aqueous  absorption  of,  446,  447,  534  ; 
exhalation  of,  532,  533. 

Variation,  individual,  1029,  1030,  1036. 

,  spontaneous,  tendency  to,  1036,  1037. 

Varieties  of  Man,  their  essential  conformity  in 
structure,  1030-1038;  in  physiological  his- 
tory, 1038,  1040;  in  psychical  endowments, 


1040-1041;   in  languages,  1041,   1042   (see 
Races). 

Vasa  lutea,  992  note. 

Vascular  Area,  991  ;  formation  of  vessels  in, 
165,  299. 

Layer  of  Germinal  membrane,  990,  991. 

Glands,   455;     see     Spleen,    Suprarenal, 

ThymuSi  and  Thyroid  bodies. 

Vegetable  substances  adapted  for  Human  food, 
375-381 ;  their  dietetic  uses,  381-383. 

Vegetables,  movements  of,  130. 

Veins,  movement  of  Blood  in,  497-500;  struc- 
ture and  properties  of,  497,498;  causes  of 
motion  of  blood  in,  498,499;  influence  of 
gravity  on,  499, 500;  effects  of  rieficient  toni- 
city  on,  499. 

Vena  Portae,  distribution  of,  in  liver,  583,  584; 
blood  of,  181,  182. 

Vena?  Azygos,  996. 

Venous  and  Arterial  Blood,  differences  of.  178- 
181. 

Ventilation,  effects  of  deficient,  538-546. 

Ventricles  of  Heart,  movements  of,  472,  473  ; 
relative  thickness  of,  474,  475;  capacity  of, 
475  ;  sounds  produced  by,  476-477  ;  quantity 
of  blood  propelled  by,  478,  479;  force  of 
propulsion  by,  479,  480. 

Vertebra,  typical,  1006-1007. 

Vertebra?,  cranial,  1007,  1008. 

Vertebral  Column,  first  indications  of,  990; 
subsequent  development  of,  1005. 

Vertebrata,  distinguished  by  Intelligence,  and 
by  possession  of  Cerebrum,  644;  subser- 
viency of  entire  organism  to  Nervous  System 
in,  645. 

Vesicles  of  evolution  of  Spermatozoa,  954. 

Vesicula  prostatica,  1003. 

Vesicular  nervous  substance,  338-340. 

Vessels,  Sanguiferous;  see  Arteries,  Capillaries, 
and  Veins. 

Absorbent;  see  Lacteals  and  Lymphatics. 

Vestibular  cavity  of  ear,  894,  904. 

Viability  of  Foetus,  984  ;  relative,  of  Male  and 
Female,  at  different  ages,  1015,  1016. 

Villi,  Intestinal,  232,  239;  structure  and  action 
of,  439-442  ;  rhythmical  movements  of,  440. 

ofChorion,  974;  of  placenta,  975,  976. 

Virility,  protracted,  956. 

Visceral  system  ;  see  Sympathetic  System. 

Vision,  sense  of,  873-893 ;  special  use  of,  in 
guiding  locomotive  actions,  723,  724  ;  optical 
conditions  of,  873-877;  defective,  877; 
nervous  apparatus  of,  878-880 ;  limits  of, 
8S2  ;  mental  participation  in,  882,  890  ;  con- 
nection of,  with  touch,  882  ;  erect,  883,  884; 
single,  with  two  eyes,  884,  885;  appreciation 
of  solid  forms  by,  885-887  ;  of  distance,  887, 
888;  of  size,  888,  889;  persistence  of  im- 
pressions, 890,  891  ;  complementary  colors, 
891  ;  other  modifications  of  color,  892  ;  want 
of  power  to  distinguish  colors,  892;  vanish- 
ing of  images,  893;  representation  of  retina 
itself,  893. 

Vital  Capacity  of  lungs,  521-522 

Force,  its  agency  in  the  living  body,  119  ; 

conditions  of  its  exercise,  140-144;  its  re- 
lations to  Physical  Forces,  143-146. 

Vitellin,  57. 

Vitelline  vesicle  and  duct,  990,  991,  994. 

vessels,  991,  992. 

Vitellus  of  ovum,  95S  ;  segmentation  of,  988, 
989. 


INDEX   OF    SUBJECTS. 


1091 


Vitreous  body,  structure  and  nutrition  of,  266. 

Vocalization,  automatic  action  of  muscles  of, 
722,  723. 

Vocal  Ligaments;  see  Chordae  Vocales. 

Voice,  ordinary  mode  of  production  of,  932  ; 
falsetto,  mode  of  production  of,  933,  934 
(see  Larynx). 

Volition,  action  of,  on  the  Body,  793-795;  on 
the  Mind,  795-796  (see  Will). 

Volitional  actions,  768  note;  influence  of  emo- 
tions on,  768,  769;  dependence  of,  upon 
previous  idea  of  success,  769,  793,  794,  798  ; 
(see  Will). 

Voluntary  Movements,  their  dependence  on 
guiding  sensations,  722-724;  performed  by 
the  instrumentality  of  the  Sensori-motor  ap- 
paratus, 724-728;  not  definitely  distinguish- 
able from  involuntary  movements,  909-910; 
impulse  to  them  originates  in  Cerebrum, 
754  (see  Volitional  Actions). 

Vomiting,  reversed  action  of  oesophagus  in, 
404  ;  action  of  stomach  in,  407,  408. 

Vowel-sounds,  production  of,  935-937. 


W. 


Walking,  automatic  action  of,  698-699. 

Wandsworth,  cholera  at,  542. 

Waste  of  Tissues;  see  Disintegration  and  De- 
generation. 

Water,  proportion  of,  in  different  tissues,  100  ; 
its  uses  in  the  economy,  100,  101  ;  propor- 
tion of,  in  blood,  170;  influence  of  ingestion 
of  fluid  on,  177  ;  alterations  in,  produced  by 
disease,  190;  importance  of,  in  diet,  380 ; 
effects  of  impurities  of,  389. 

Water-dressing  for  wounds,  564. 

Weight  of  Foetus  at  different  ages,  1012-1014; 
of  male  and  female  at  after  periods  of  life, 
1016,  1017. 

White  Corpuscles;  see  Blood- Corpuscles,  Co- 
lorless. 

White  Fibrous  Tissue,  structure  and  composi- 
tion of,  224,  225 ;  presence  of,  in  Areolar 
tissue,  226,  227 ;  development  and  repara- 
tion of,  227-229. 

Will,  freedom  of,  775,  817;  its  influence  on 
the  Organism  in  general,  793-795;  its 
manifestation  in  Force,  37,  774,  787;  its 
domination  over  reflex  actions,  648,  649  ; 
its  operation  through  automatic  apparatus, 


725-728;  requires  guiding  sensations  for 
its  direction  to  the  muscles,  722-724;  in- 
fluence of  emotional  states  of  mind  upou 
its  exercise,  768,  769  ;  influence  of  idea- 
tional  states,  793,  794. 

Its  influence  on  Psychical  action,  649-650, 
775,  788-790,  795-796,  810-814;  effects 
of  its  suspension,  in  Reverie,  796,  797  ; 
in  "  Biological"  state,  797,  798  ;  in  Som- 
nambulism, 800,  801  ;  in  Dreaming,  802- 
804;  in  Delirium  and  Mania,  804-806;  in 
Insanity,  806-810;  government  of  the 
conduct  by,  811,  812,  817-819. 
Its  general  control  over  Automatic  actions 
of  nervous  system,  831  ;  over  Cerebral 
action,  832-836;  over  Sensory  Ganglia, 
836,  837  ;  over  Spinal  Axis,  842. 

Winking,  act  of,  697. 

Wounds,  healing  of,  561-566. 


Xanthine,  92. 


X. 


Y. 


Yawning,  act  of,  518  ;  consensual  nature  of, 
720. 

Yelk,  composition  of,  958;  segmentation  of, 
988,989. 

Yellow  Fever,  muscular  actions  after  death 
from,  327;  continued  flow  of  blood,  492; 
subsequent  production  of  heat,  619. 

yellow  Fibrous  Tissue,  structure  and  composi- 
tion of,  225,  226  ;  presence  of,  in  Areolar 
tissue,  226,  227  ;  development  of,  228. 

Young  animals,  inferior  heat-producing  power 
of,  629-631. 


Zona  pellucida,  958. 

Zymotic  diseases,  favored  by  previous  state  of 
blood,  216-220;  by  putrescent  food,  387, 
388  ;  by  putrescent  water,  389  ;  by  starva- 
tion, 395;  by  deficiency  of  respiration,  538- 
546. 


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OF  MEDICAL  SCIENCE,  containing  Anatomy,  Physiology,  Surgery,  Midwifery, 
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1000  pages,  with  350  illustrations.  I2P  See  NEILL. 


ABEL  (F.    A.),    F.  C.  S. 
Professor  of  Chemistry  in  the  Royal  Military  Academy,  Woolwich. 

AND 

C.    L.    BLOXAM, 

Formerly  First  Assistant  at  the  Royal  College  of  Chemistry. 

HANDBOOK  OF  CHEMISTRY,  Theoretical,  Practical,  and  Technical,  with  a 
Recommendatory  Preface  by  Dr.  HOFMANN.  In  one  large  octavo  volume  of  662  pages,  with 
illustrations.  (Now  Ready.} 

There  was  still  wanting  some  book  which  should  who  resolves  to  pursue  for  himself  a  steady  search 
aid  the  young  analytical  chemist  through  all  the  into  the  chemical  mysteries  of  creation.  For  such 
phases  of  the  science.  The  "  Handbook"  of  Messrs,  a  student  the  'Handbook'  will  prove  an  excellent 
Abel  and  Bloxam  appears  to  supply  that  want.  As  '  guide,  since  he  will  find  in  it,  not  merely  the  most 
Dr.  H  of  maim  says  in  his  brief  Preface,  "  The  pre-  approved  modes  of  analytical  investigation,  but 
sent  volume  is  a  synopsis  of  their  (the  authors')  ex-  descriptions  of  the  apparatus  necessary;  with  such 
perience  in  laboratory  teaching  ;  it  gives  the  neces-  i  manipulatory  details  as  rendered  Faraday's  '  Che- 
sary  instruction  in  chemical  manipulation,  a  concise  j  mical  Manipulations'  so  valuable  at  the  time  of  its 
account  of  general  chemistry  as  far  as  it  is  involved  publication.  Beyond  this,  the  importance  of  the 
in  the  operations  of  the  laboratory,  and  lastly,  quali-  work  is  increased  by  the  introduction  of  much  of  the 
tative  and  quantitative  analysis.  It  must  be  under-  technical  chemistry  of  the  manufactory." — Athe- 
stood  that  this  is  a  work  fitted  for  the  earnest  student,  :  nacum. 


ASHWELL   (SAMUEL),  M.  D. 
A  PRACTICAL  TREATISE  ON  THE  DISEASES  PECULIAR  TO  WOMEN. 

Illustrated  by  Cases  derived  from  Hospital  and  Private  Practice.    With  Additions  by  PAUL  BECK 
GODDARD,  M.  D.     Second  American  edition.     In  one  octavo  volume,  of  520  pages. 


ARNOTT   (NEILL),  M.  D. 
ELEMENTS 'OF    PHYSICS;    or  Natural  Philosophy,  General  and  Medical. 

Written  for  universal  use,  in  plain  or  non-technical  language.    A  new  edition,  by  ISAAC  HAYS, 
M.  D.     Complete  in  one  octavo  volume,  of  484  pages,  with  about  two  hundred  illustrations. 

BENNETT   (J.    HUGHES),    M.  D.,    F.  R.  S.  E., 

Professor  of  Clinical  Medicine  in  the  University  of  Edinburgh,  &c. 

THE  PATHOLOGY  AND  TREATMENT  OF  PULMONARY  TUBERCU- 
LOSIS, and  on  the  Local  Medication  of  Pharyngeal  and  Laryngeal  Diseases  frequently  mistaken 
for  or  associated  with,  Phthisis.  In  one  handsome  octavo  volume,  with  beautiful  wood-cuts. 
(Now  Ready.) 


it  may  be  most  effectually  carried  intovprac- 
ir  readers  will  learn  from  Dr.  Bennett's  pages, 


How 
tice,  ou1 

especially  from  the  histories  of  the  valuable  and  in- 
teresting cases  which  he  records.  Indeed,  if  the  au- 
thor had  only  reported  these  cases  he  would  have 
benefited  his  profession,  and  deserved  our  thanks.  As 
it  is,  however,  his  whole  volume  is  so  replete  with 
valuable  matter,  that  we  feel  bound  to  recommend 
our  readers,  one  and  all,  to  peruse  it. — Land.  Lancet. 


The  elegant  little  treatise  before  as  shows  how 
faithfully  and  intelligently  these  investigations  have 
been  pursued,  and  how  successfully  the  author's 
studies  have  resulted  in  clearing  up  some  of  the  most 
doubtful  points  and  conflicting  doctrines  hitherto 
entertained  in  reference  to  the  history  and  treatment 
of  pulmonary  tuberculosis. — Ar.  Y.  Journal  of  Medi- 
cal and  Collateral  Science  j  March,  1854. 


BENNETT   (HENRY),  M.  D, 
A  PRACTICAL   TREATISE    ON   INFLAMMATION  OF  THE  UTERUS, 

ITS  CERVIX  AND  APPENDAGES,  and  on  its  connection  with  Uterine  Disease.  Fourth 
American,  from  the  third  and  revised  London  edition.  In  one  neat  octavo  volume,  of  430  pages, 
with  wood-cuts.  (Now  Ready.) 

This  edition  will  be  found  materially  improved  over  its  predecessors,  the  author  having  carefully 
revised  it,  and  made  considerable  additions,  amounting  to  about  seventy-five  pages. 

This  edition  has  been  carefully  revised  and  altered,     that  the  bulk  of  the  profession  are  not  fully  alive  to 


the  importance  and  frequency  of  the  disease  of  which 
it  takes  cognizance.  The  present  edition  is  so  much 
enlarged,  altered,  and  improved,  that  it  can  scarcelv 
he  considered  the  same  work.—  Dr.  banking's  Ab- 


and various  additions  have  been  made,  which  render 

it  more  complete,  and,  if  possible,  more  worthy  of 

the  high   appreciation   in  which  it  is  held  by  the 

medical  profession  throughout  the  world.    A  copy 

should  be  in  the  possession  of  every  physician. — 

Charleston  Med.  Journal  and  Review,  March,  1854. 
We  are  firmly  of  opinion  that  in  proportion  as  a  i      Few  works  issue  from  the  medical  press  which 

knowledge  of  uterine  diseases  becomes  more  appre-  j  are  at  once  original  and  sound  in  doctrine  ;  but  such, 

ciated.  this  work  will  be  proportionably  established  !  we  "*!  assured,  is  the  admirable  treatise  now  before 

us.  The  important  practical  precepts  which  the 
author  inculcates  are  all  rigidly  deduced  from  facts. 
.  .  .  Every  page  of  the  book  is  good,  and  eminently 
practical.  ...  So  far  a«  we  know  and  believe,  it  is 
the  best  work  on  the  subject  of  which  it  treats  — 


as  a  text- book  in  the  profession. — The  Lancet. 

When,  a  few  years  back,  the  first  edition  of  the 
present  work  WHS  published,  the  subject  was  one  al- 
most entirely  unknown  to  the  obstetrical  celebrities 
of  the  day  ;  and  even  now  we  have  reason  to  know 


Monthly  Journal  of  Medical  Science. 


BLANCHARD   &    LEA'S   MEDICAL 


BEALE  (LIONEL   JOHN),  M.  R.  C.  S.,  &c. 
THE    LAWS   OF    HEALTH   IN   RELATION   TO    MIND    AND   BODY. 

A  Series  of  Letters  from  an  old  Practitioner  to  a  Patient.     In  one  handsome  volume,  royal  12mo., 
extra  cloth. 


BILLING    (ARCHIBALD),  M.  D. 

THE  PRINCIPLES  OF  MEDICINE.     Second  American,  from  the  Fifth  and 
Improved  London  edition.     In  one  handsome  octavo  volume,  extra  cloth,  250  pages. 


BLAKISTON    (PEYTON),  M .  D.,  F.  R.  S.,  &c. 
PRACTICAL    OBSERVATIONS    ON    CERTAIN    DISEASES    OF    THE 

CHEST,  and  on  the  Principles  of  Auscultation.    In  one  volume.  8vo.,  pp.  384. 


BURROWS    (GEORGE),   M.D. 

ON  DISORDERS  OF  THE  CEREBRAL  CIRCULATION,  and  on  the  Con- 
nection between  the  Affections  of  the  Brain  and  Diseases  of  the  Heart.  In  one  8vo.  vol.,  witfc 
colored  plates,  pp.  216. 

BUDD  (GEORGE),  M.  D.,  F.  R.  S., 

Professor  of  Medicine  in  King's  College,  London. 

ON  DISEASES   OF  THE   LIVER.     Second  American,  from  the  second  and 

enlarged  London  edition'.     In  one  very  handsome  octavo  volume,  with  four  beautifully  colored 
plates,  and  numerous  wood-cuts,     pp.  468.    New  edition.     (Just  Issued.) 

The  reputation  which  this  work  has  obtained  as  a  full  and  practical  treatise  on  an  important  clas* 
of  diseases  will  not  be  diminished  by  this  improved  and  enlarged  edition.  It  has  been  carefully  and 
thoroughly  revised  by  the  author ;  the  number  of  plates  has  been  increased,  and  the  style  of  its  me- 
chanical execution  will  be  found  materially  improved. 


The  full  digest  we  have  given  of  the  new  matter 
introduced  into  the  present,  volume,  is  evidence  of 
the  value  we  place  on  it.  The  fact  that  the  profes- 
sion has  required  a  second  edition  of  a  monograph 
such  as  that  before  us,  bears  honorable  testimony 
to  its  usefulness.  For  many  years,  Dr.  Budd's 


work  must  be  the  authority  of  the  great  mass  of 


British  practitioners  on  the  hepatic  diseases  ;  and  it 
is  satisfactory  that  the  subject  has  been  taken  up  by 
so  able  and  experienced  a  physician. — British  and 
Foreign  Medico-Chirurgica 


nrSl 
lei 


BUSHNAN   (J.  S.),    M.  D. 
THE  PHYSIOLOGY  OF   ANIMAL  AND  VEGETABLE   LIFE;  a  Popular 

Treatise  on  the  Functions  and  Phenomena  of  Organic  Life.  To  which  is  prefixed  a  Brief  Expo- 
sition of  the  great  departments  of  Human  Knowledge.  In  one  handsome  royal  12mo.  volume, 
with  over  one  hundred  illustrations. 

Though  cast  in  a  popular  form  and  manner,  this  work  is  the  production  of  a  man  of  science,  and 
presents  its  subject  in  its  latest  development,  based  on  truly  scientific  and  accurate  principles. 
It  may  therefore  be  consulted  with  interest  by  those  who  wish  to  obtain  in  a  concise  form,  and  at 
a  very  low  price,  a  resume  of  the  present  state  of  animal  and  vegetable  physiology. 

BLOOD  AND  URINE  (MANUALS  ON). 
BY  JOHN  WILLIAM   GRIFFITH,   G.  OWEN   REESE,   AND  ALFRED 

MARKWICK.     One  thick  volume,  royal  12mo.,  extra  cloth,  with  plates,     pp.  460. 

BRODIE  (SIR  BENJAMIN   C.),  M.  D.,  &c. 
OLINICAL  LECTURES  ON  SURGERY.     1  vol.  8vo.,  cloth.     350pp. 

BY   THE   SAME    AUTHOR. 

SELECT  SURGICAL  WORKS,  1  vol.  8vo.  leather,  containing  Clinical  Lectures 

on  Surgery,  Diseases  of  the  Joints,  and  Diseases  of  the  Urinary  Organs. 


BIRD  (GOLDING),  A.  M.,  M.  D.,  &c. 
URINARY     DEPOSITS:     THEIR     DIAGNOSIS,    PATHOLOGY,    AND 

THERAPEUTICAL  INDICATIONS.    A  new  and  enlarged  American,  from  the  last  improved 

London  edition.    With  over  sixty  illustrations.     In  one  royal  12mo.  volume,  extra  cloth. 

The  new  edition  of  Dr.  Bird's  work,  though  not  j  suits  of  those  microscopical  and  chemical  researches 


mcreased  in  size,  has  been  greatly  modified,  and 
much  of  it  rewritten.  It  now  presents,  in  a  com- 
pendious form,  the  gist  of  all  that  is  known  and  re- 
liable in  this  department.  From  its  terse  style  and 
Convenient  size,  it  is  particularly  applicable  to  the 
«tudent,  to  whom  we  cordially  commend  it. —  The 
Medical  Examiner. 

It  can  scarcely  be  necessary  for  us  to  say  anything 
of  the  merits  of  this  well-known  Treatise,  which  so 


egarding  the  physiology  and  pathology  of  the  uri- 
nary secretion,  which  nave  contributed  so  much  to 
the  increase  of  oar  diagnostic  powers,  and  to  the 
extension  and  satisfactory  employment  of  our  thera- 
peutic resources.  In  the  preparation  of  this  new 
edition  of  his  work,  it  is  obvious  that  Dr.  Goldjmg 
Bird  has  spared  no  pains  to  render  it  a  faithful  repre- 
sentation of  the  present  state  of  scientific  knowledge 
on  the  subject  it  embraces.—  The  British  and  Foreign 
Medieo-C kirurgical  Review. 


admirably  brings  into  practical  application  the  re- 

BY   THE   SAME   AUTHOR. 

ELEMENTS  OF  NATURAL  PHILOSOPHY;  being  an  Experimental  Intro- 
duction to  the  Physical  Sciences.  Illustrated  with  nearly  four  hundred  wood-cuts.  From  lh« 
third  London  edition.  In  one  neat  volume,  royal  12mo.  pp.  402. 


AND    SCIENTIFIC    PUBLICATIONS. 


BARTLETT  (ELISHA),  M.  D., 

Professor  of  Materia  Medica  and  Medical  Jurisprudence  in  the  College  of  Physicians  and 
Surgeons,  New  York. 

THE   HISTORY,  DIAGNOSIS,   AND  TREATMENT   OF  THE   FEVERS 

OF  THE  UNITED  STATES.     Third  edition,  revised  and  improved.     In  one  octavo  volume, 

of  six  hundred  pages,  beautifully  printed,  and  strongly  bound. 

In  preparing  a  new  edition  of  this  standard  work,  the  author  has  availed  himself  of  such  obser- 
vations and  investigations  as  have  appeared  since  the  publication  of  his  last  revision,  and  he  has 
endeavored  in  every  way  to  render  it  worthy  of  a  continuance  of  the  very  marked  favor  with  which 
it  has  been  hitherto  received. 


The  masterly  and  elegant  treatise,  by  Dr.  Bartlett 
is  invaluable  to  the  American  student  and  practi- 
tioner.— Dr.  Holmes's  Report  to  the  Nat.  Med.  Asso- 
ciation. 

We  regard  it,  from  the  examination  we  have  made 
of  it,  the  best  work  on  fevers  extant  in  our  language, 
and  as  such  cordially  recommend  it  to  the  medical 
public. — St.  Louis  Medical  and  Surgical  Journal. 

Take  it  altogether,  it  is  the  m«st  complete  history 
of  our  fevers  which  has  yet  been  published,  and 
every  practitioner  should  avail  himself  of  its  con- 
tents.— The  Western  Lancet. 


Of  the  value  and  importance  of  such  a  work,  it  is 
needless  here  to  speak;  the  profession  of  the  United 
States  owe  much  to  the  author  for  the  very  able 
volume  which  he  has  presented  to  them,  and  for  the 
careful  and  judicious  manner  in  which  he  has  exe- 
cuted his  task.  No  one  volume  with  which  we  are 
acquainted  contains  so  complete  a  history  of  our 
fevers  as  this.  To  Dr.  Bartlett  we  owe  our  best 
thanks  for  the  very  able  volume  he  has  given  us,  as 
embodying  certainly  the  most  complete,  methodical, 
and  satisfactory  account  of  our  fevers  anywhere  to 
be  met  with.— T/ie  Charleston  Med.  Journal  and 
Review . 


BUCKLER  <T.  H.),  M.  D., 

Formerly  Physician  to  the  Baltimore  Almshouse  Infirmary,  &c. 

ON  THE  ETIOLOGY,   PATHOLOGY,  AND  TREATMENT   OF   FIBRO- 

BRONCHITIS  AND  RHEUMATIC  PNEUMONIA.    In  one  handsome  octavo  volume,  extra 
cloth.     (Just  Issued.) 

BOWMAN  (JOHN   EJ,  M.D. 
PRACTICAL   HANDBOOK   OF   MEDICAL    CHEMISTRY.     In  one  neat 

volume,  royal  12mo.,  with  numerous  illustrations,     pp.  288. 

BY  THE  SAME  AUTHOR. 

INTRODUCTION    TO    PRACTICAL    CHEMISTRY,    INCLUDING   ANA- 
LYSIS.   With  numerous  illustrations.    In  one  neat  volume,  royal  12mo.    pp.  350. 


BARLOW   (GEORGE  H.),   M.  D. 
A  MANUAL  OF  THE  PRINCIPLES  AND  PRACTICE   OF  MEDICINE. 

In  one  octavo  volume.     (Preparing-.) 


CYCLOPAEDIA    OF    PRACTICAL    MEDICINE. 

Edited  by  DUNGLISON,  FORBES,  TWEEDIE,  and  CONOLLY,  in  four  large  octavo 
volumes,  strongly  bound.     Jg^r  See  DUNGLISON. 


COLOMBAT  DE  L'ISERE. 
A  TREATISE   ON   THE    DISEASES    OF   FEMALES,  and  on  the  Special 

Hygiene  of  their  Sex.    Translated,  with  many  Notes  and  Additions,  by  C.  D.  MEIGS,  M.  D. 

Second  edition,  revised  and  improved.    In  one  large  volume,  octavo,  with  numerous  wood-culs. 

pp.  720. 

The  treatise  of  M.  Colombat  is  a  learned  and  la-  i  M.  Colombat  De  L'Isere  has  not  consecrated  tea 
borious  commentary  on  these  diseases,  indicating  years  of  studious  toil  and  research  to  the  frailer  gex 
very  considerable  research,  great  accuracy  of  judg-  in  vain;  and  although  we  regret  to  hear  it  is  at  the 
ment,  and  no  inconsiderable  personal  experience. 
With  the  copious  notes  and  additions  of  its  experi- 
enced and  very  erudite  translator  and  editor,  Dr. 
Meigs,  it  presents,  probably,  one  of  the  most  com- 
plete and  comprehensive  works  on  the  subject  we 
possess. — American  Med.  Journal. 


expense  of  health,  he  has  imposed  a  debt  of  gratitude 
as  well  upon  the  profession,  as  upon  the  mothers  and 
daughters  of  beautiful  France,  which  that  gallant 
nation  knows  best  how  to  acknowledge.— New  Or- 
leans Medical  Journal. 


COPLAND  (JAMES),  M.  D.,  F.  R.  S.,  &c. 
OF  THE  CAUSES,  NATURE,  AND  TREATMENT  OF  PALSY  AND 

APOPLEXY,  and  of  the  Forms,  Seats,  Complications,  and  Morbid  Relations  of  Paralytic  and 
Apoplectic  Diseases.    In  one  volume,  royal  12mo.,  extra  cloth,    pp.  326. 


CLYMER  (MEREDITH),  M.  D.,  &c. 
FEVERS;     THEIR    DIAGNOSIS,    PATHOLOGY,    AND    TREATMENT, 

Prepared  and  Edited,  with  large  Additions,  from  the  Essays  on  Fever  in  Tweedie's  Library  of 
Practical  Medicine.    In  one  octavo  volume,  of  600  pages. 


CARSON  (JOSEPH),  M.  D., 

Professor  of  Materia  Medica  and  Pharmacy  in  the  University  of  Pennsylvania. 

SYNOPSIS  OF  THE  COURSE  OF  LECTURES  ON  MATERIA  MEDICA 

AND  PHARMACY,  delivered  in  the  University  of  Pennsylvania.    In  one  very  neat  octavo 
volume,  of  208  pages. 


JBLANCHARD  &  LEA'S   MEDICAL 


CARPENTER  (WILLIAM    B.),   M .  D.,  F.  R.  S.,  &.C., 

Examiner  in  Physiology  and  Comparative  Anatomy  in  the  University  of  London. 

PRINCIPLES  OF  HUMAN  PHYSIOLOGY;  with  their  chief  applications  t© 
Psychology,  Pathology,  Therapeutics,  Hygiene,  and  Forensic  Medicine.  Fifth  American,  from 
the  fourth  and  enlarged  London  edition.  With  three  hundred  and  fourteen  illustrations.  Edited, 
with  additions,  by  FRANCIS  GURNEY  SMITH,  M.  D.,  Professor  of  the  Institutes  of  Medicine  in  the 
Pennsylvania  Medical  College,  &c.  In  one  very  large  and  beautiful  octavo  volume,  of  about  1100 
large  pages,  handsomely  printed  and  strongly  bound  in  leather,  with  raised  bands.  New  edition. 
(Lately  Issued.) 


The  most  complete  work  on  the  science  in  our 
language. — Am.  Med.  Journal. 

The  most  complete  exposition  of  physiology  which 
any  language  can  at  present  give.— Brit,  and  For. 
Med.-Chirurg.  Review. 

We  have  thus  adverted  to  some  of  the  leading 
"additions  and  alterations,"  which  have  been  in- 
troduced by  the  author  into  this  edition  of  his  phy- 
siology. These  will  be  found,  however,  very  far  to 
exceed  the  ordinary  limits  of  a  new  edition,  "  the 
old  materials'  having  been  incorporated  with  the 
new,  rather  than  the  new  with  the  old."  It  now 
certainly  presents  the  most  complete  treatise  on  the 
subject  within  the  reach  of  the  American  reader ; 
and  while,  for  availability  as  a  text-book,  we  may 
perhaps  regret  its  growth  in  bulk,  we  are  sure  that 
tiie  student  of  physiology  will  feel  the  impossibility 
of  presenting  a  thorough  digest  of  the  facts  of  the 
science  within  a  more  limited  compass.— Medical 
Examiner. 

The  greatest,  the  most  reliable,  and  the  best  book 
on  the  subject  which  we  know  of  in  the  English 
language.— Stethoscope. 

The  most  complete  work  now  extant  in  oar  lan- 
guage.— N.  O.  Med.  Register. 

The  changes  are  too  numerous  to  admit  of  an  ex- 
tended notice  in  this  place.  At  every  point  where 
the  recent  diligent  labors  of  organic  chemists  and 
micrographers  have  furnished  interesting  and  valu- 
able facts,  they  have  been  appropriated,  and  no  pains 
have  been  spared,  in  so  incorporating  and  arranging 
them  that  the  work  may  constitute  one  harmonious 
system. — Southern  Med.  and  Surg.  Journal. 


The  best  text-book  in  the  language  on  this  ex- 
tensive subject. — London  Med.  Times. 

A  complete  cyclopaedia  of  this  branch  of  science. 
— N.  Y.  Med.  Times. 

The  standard  of  authority  on  physiological  sub- 
jects. *  *  *  In  the  present  edition,  to  particularize 
the  alterations  and  additions  which  have  been  made, 
would  require  a  review  of  the  whole  work,  since 
scarcely  a  subject  has  not  been  revised  and  altered, 
added  to,  or  entirely  remodelled  to  adapt  it  to  the 
present  state  of  the  science. — Charleston  Med.  Journ. 

Any  reader  who  desires  a  treatise  on  physiology 
may  feel  himself  entirely  safe  in  ordering  this. — 
Western  Med.  and  Surg.  Journal. 

From  this  hasty  and  imperfect  allusion  it  will  be 
seen  by  our  readers  that  the  alterations  and  addi- 
tions to  this  edition  render  it  almost  a  new  work — 
and  we  can  assure  our  readers  that  it  is  one  of  the 
best  summaries  of  the  existing  facts  of  physiological 
science  within  the  reach  of  the  English  student  and 
physician. — JV.  Y.  Journal  of  Medicine. 

The  profession  of  this  country,  and  perhaps  also 
of  Europe,  have  anxiously  and  for  some  time  awaited 
the  announcement  of  this  new  edition  of  Carpenter's 
Human  Physiology.  His  former  editions  have  for 
many  years  been  almost  the  only  text-book  on  Phy- 
siology in  all  our  medical  schools,  and  its  circula- 
tion among  the  profession  has  been  unsurpassed  by 
any  work  in  any  department  of  medical  science. 

it  is  quite  unnecessary  for  us  to  speak  of  this 
work  as  its  merits  would  justify.  The  mere  an- 
nouncement of  its  appearance  will  afford  the  highest 
pleasure  to  every  student  of  Physiology,  while  its 
perusal  will  be  of  infinite  service  in  advancing 
physiological  science. — Ohio  Med.  and  Snrg.  Journ. 


BY  THE  SAME  AUTHOR.     (Now  Ready.) 

PRINCIPLES  OF  COMPARATIVE   PHYSIOLOGY.     New  American,  from 

the  Fourth  and  Revised  London  edition.     In  one  large  and  handsome  octavo  volume,  with  over 
three  hundred  beautiful  illustrations. 

The  delay  which  has  existed  in  the  appearance  of  this  work  has  been  caused  by  the  very  thorough 
revision  and  remodelling  which  it  has  undergone  at  the  hands  of  the  author,  and  the  large  number 
of  new  illustrations  which  have  been  prepared  for  it.  It  will,  therefore,  be  found  almost  a  new 
work,  and  fully  up  to  the  day  in  every  department  of  the  subject,  rendering  it  a  reliable  text-book 
for  all  students  engaged  in  this  branch  of  science.  Every  effort  has  been  made  to  render  its  typo- 
graphical finish  and  mechanical  execution  worthy  of  its  exalted  reputation,  and  creditable  to  the 
mechanical  arts  of  this  country.  A  few  notices  of  the  last  edition  are  appended. 

Without  pretending  to  it,  it  is  an  Encyclopedia  of    critical,  and  unprejudiced  view  of  those  labors,  and 
the  subject,  accurate  and  complete  in  all  respects— 
a  truthful  reflection  of  the  advanced  state  at  which 
the  science  has  now  arrived. — Dublin  Quarterly 
Journal  of  Medical  Science. 

A  truly  magnificent  work— in  itself  a  perfect  phy- 
siological study.— Ranking^s  Abstract. 

This  work  stands  without  its  fellow.  It  is  one 
few  men  in  Europe  could  have  undertaken ;  it  is  one 
no  man,  we  believe,  could  have  brought  to  so  suc- 
cessful an  issue  as  Dr.  Carpenter.  It  required  for 
its  production  a  physiologist  at  once  deeply  read  in 
the  labors  of  others,  capable  of  taking  a  general, 


of  combining  the  varied,  heterogeneous  materials  at 
his  disposal,  so  as  to  form  an  harmonious  whole. 
We  feel  that  this  abstract  can  give  the  reader  a  very 
imperfect  idea  of  the  fulness  of  this  work,  and  no 
idea  of  its  unity,  of  the  admirable  manner  in  which 
material  has  been  brought,  from  the  most  various 
sources,  to  conduce  to  its  completeness,  of  the  lucid- 
ity of  the  reasoning  it  contains,  or  of  the  clearness 
of  language  in  whicli  the  whole  is  clothed.  Not  the 
profession  only,  but  the  scientific  world  at  large. 

this 


must  feel  deeply  indebted  to  Dr.  Carpenter  for 
great  work.     It  must,  indeed,  add  largely  even  t<* 
his  high  reputation. — Medical  Times. 

BY  THE  SAME  AUTHOR.     (Preparing.) 

THE  MICROSCOPE  AND  ITS  REVELATIONS.     In  one  handsome  volume; 

beautifully  illustrated  with  plates  and  wood-cuts. 

BY  THE  SAME  AUTHOR.     (Preparing.) 

GENERAL  PHYSIOLOGY.     In  one  large  and  very  handsome  octavo  volume, 
with  several  hundred  illustrations. 

The  subject  of  general  physiology  having  been  omitted  in  the  last  edition  oi'the  author's  "Com- 
parative Physiology,"  he  has  undertaken  to  prepare  a  volume  which  .shall  present  it  more  tho- 
roughly and  fully  than  has  yet  been  attempted,  and  which  may  be  regarded  as  an  introduction  to 
his  other  works. 


AND   SCIENTIFIC    PUBLICATIONS. 


CARPENTER  (WILLIAM  B.),   M.  D.,  F.  R.  S., 

Examiner  in  Physiology  and  Comparative  Anatomy  in  the  University  of  London. 

ELEMENTS  (OK  MANUAL)  OF  PHYSIOLOGY,  INCLUDING  PHYSIO- 
LOGICAL ANATOMY.  Second  American,  from  a  new  and  revised  London  edition.  With 
one  hundred  and  ninety  illustrations.  In  one  very  handsome  octavo  volume. 

In  publishing-  the  first  edition  of  this  work,  its  title  was  altered  from  that  of  the  London  volume, 
by  the  substitution  of  the  word  "  Elements1'  for  that  of  "  Manual,"  and  with  the  author's  sanction 
the  title  of  "  Elements"  is  still  retained  as  being  more  expressive  of  the  scope  of  the  treatise.  A 
comparison  of  the  present  edition  with  the  former  one  will  show  a  material  improvement,  the 
author  having  revised  it  thoroughly,  with  a  view  of  rendering  it  completely  on  a  level  with  the 
most  advanced  state  of  the  science.  By  condensing  the  less  important  portions,  these  numerous 
additions  have  been  introduced  without  materially  increasing  the  bulk  of  the  volume,  and  while 
numerous  illustrations  have  been  added,  and  the  general  execution  of  the  work  improved,  it  has 
been  kept  at  its  former  very  moderate  price. 


To  say  that  it  is  the  best  manual  of  Physiology 
now  before  the  public,  would  not  do  sufficient  justice 
to  the  author. — Buffalo  Medical  Journal. 

In  his  former  works  it  would  seem  that  he  had 
exhausted  the  subject  of  Physiology.  In  the  present, 
he  gives  the  essence,  as  it  were,  of  the  whole. — N.  Y, 
Journal  of  Medicine. 

Those  who  have  occasion  for  an  elementary  trea- 
tise on  Physiology,  cannot  do  better  than  to  possess 
themselves  of  the  manual  of  Dr.  Carpenter. — Medical 
Examiner. 


The  best  and  most  complete  exposd  of  modern 
Physiology,  in  one  volume,  extant  in  the  English 
language. — St.  Louis  Medical  Journal. 

With  such  an  aid  in  his  hand,  there  is  no  excuse 
for  the  ignorance  often  displayed  respecting  the  sub- 
jects of  which  it  treats.  From  its  unpretending  di- 
mensions, it  may  not  be  so  esteemed  by  those  anxious 
to  make  a  parade  of  their  erudition ;  but  whoever 
masters  its  contents  will  have  reason  to  be  proud  of 
his  physiological  acquirements.  The  illustrations 
are  well  selected  and  finely  executed.— Dublin  Med, 
Press. 


BY   THE   SAME   AUTHOR. 

A  PRIZE  ESSAY  ON  THE  USE  OF  ALCOHOLIC  LIQUORS  IN  HEALTH 

AND  DISEASE.    New  edition,  with  a  Preface  by  D.  F.  CONDIE,  M.  D.,  and  explanations  or 
scientific  words.    In  one  neat  12mo.  volume.     (Now  Ready.) 

This  new  edition  has  been  prepared  with  a  view  to  an  extended  circulation  of  this  important  little 
work,  which  is  universally  recognized  as  the  best  exponent  of  the  laws  of  physiology  and  pathology 
applied  to  the  subject  of  intoxicating  liquors,  in  a  form  suited  both  for  the  profession  and  the  public. 
To  secure  a  wider  dissemination  of  its  doctrines  the  publishers  have  done  up  copies  in  flexible 
cloth,  suitable  for  mailing,  which  will  be  forwarded  through  the  post-office,  free,  on  receipt  of  fifty 
cents.  Societies  and  others  supplied  in  quantities  for  distribution  at  a  liberal  deduction. 


CHELIUS   (J.  M.),   M.  D., 

Professor  of  Surgery  in  the  University  of  Heidelberg,  &c. 

A  SYSTEM  OF  SURGERY.     Translated  from  the  German,  and  accompanied 

with  additional  Notes  and  References,  by  JOHN  F.  SOUTH.     Complete  in  three  very  large  octavo 
volumes,  of  nearly  2200  pages,  strongly  bound,  with  raised  bands  and  double  titles. 


We  do  not~hesitate  to  pronounce  it  the  best  and 
most  comprehensive  system  of  modern  surgery  with 
which  we  are  acquainted. — Medic o-Chirurgical  Re- 
view. 

The  fullest  and  ablest  digest  extant  of  all  that  re- 
lates to  the  present  advanced  state  of  surgical  pa- 
thology.— American  Medical  Journal. 

As  complete  as  any  system  of  Surgery  can  well 
be. — Southern  Medical  and  SurgicalJournal. 


The  most  learned  and  complete  systematic  treatise 
now  extant. — Edinburgh  Medical  Journal. 

A  complete  encyclopaedia  of  surgical  science — a 
very  complete  surgical  library — by  far  the  most 
complete  and  scientific  system  of  surgery  in  the 
English  language.— N.  Y.  Journal  of  Medicine. 

The  most  extensive  and  comprehensive  account  of 
the  art  and  science  of  Surgerv  in  our  language. — 
Lancet. 


CHRISTISON   (ROBERT),  M.  D.,  V.  P.  R.  S.  E.,  &c. 

A  DISPENSATORY;  or.  Commentary  on  the  Pharmacopoeias  of  Great  Britain 
and  the  United  States ;  comprising  the  Natural  History,  Description,  Chemistry,  Pharmacy,  Ac- 
tions, Uses,  and  Doses  of  the  Articles  of  the  Materia  Medica.  Second  edition,  revised  and  im- 
proved, with  a  Supplement  containing  the  most  important  New  Remedies.  With  copious  Addi- 
tions, and  two  hundred  and  thirteen  large  wood-engravings.  By  R.  EGLESFELD  GRIFFITH,  M.  D. 
In  one  very  large  and  handsome  octavo  volume,  of  over  1000  pages. 


It  is  not  needful  that  we  should  compare  it  with 
the  other  pharmacopeias  extant,  which  enjoy  and 
merit  the  confidence  of  the  profession  :  it  is  enough 
ro  say  that  it  appears  to  us  as  perfect  as  a  Dispensa- 
tory, in  the  present  state  of  pharmaceutical  science, 
could  be  made.  If  it  omits  any  details  pertaining  to 
this  branch  of  knowledge  which  the  student  has  a 
right  to  expect  in  such  a  work,  we  confess  the  omis- 
sion has  escaped  our  scrutiny.  We  cordially  recom- 
mend this  work  to  such  of  our  readers  as  are  in  need 
of  a  Dispensatory.  They  cannot  make  choice  of  a 
better. — Western  Journ.  of  Medicine  and  Surgery. 


There  is  not  in  any  language  a  more  complete  and 
perfect  Treatise.— N.  Y.  Annalist. 

In  conclusion,  we  need  scarcely  say  that  we 
strongly  recommend  this  work  to  all  classes  of  our 
readers.  As  a  Dispensatory  and  commentary  on  the 
Pharmacopoeias,  it  is  unrivalled  in  the  English  or 
any  other  language. — The  Dublin  Quarterly  Journal . 

We  earnestly  recommend  Dr.  Christison's  Dis- 
pensatory to  all  our  readers,  as  an  indispensable 
companion,  not  in  the  Study  only,  but  in  theSurgety 
alao.— British  and  Foreign  Medical  Review. 


s 


BLANCHARD  &  LEA'S  MEDICAL 


CONDIE  (D.  F.),  M.  D.,  &c. 
A  PRACTICAL  TREATISE  ON  THE  DISEASES  OF  CHILDREN.    Fourth 

edition,  revised  and  augmented.  In  one  large  volume,  8vo.,  of  nearly  750  pages.  (Just  Issued.') 
FROM  THE  AUTHOR'S  PREFACE. 

The  demand  for  another  edition  has  afforded  the  author  an  opportunity  of  again  subjecting  the 
entire  treatise  to  a  careful  revision,  and  of  incorporating  in  it  every  important  observation  recorded 
since  the  appearance  of  the  last  edition,  in  reference  to  the  pathology  and  therapeutics  of  the  several 
diseases  of  which  it  treats. 

In  the  preparation  of  the  present  edition,  as  in  those  which  have  preceded,  while  the  author  has 
appropriated  to  his  use  every  important  fact  that  he  has  found  recorded  in  the  works  of  others, 
having  a  direct  bearing  upon  either  of  the  subjects  of  which  he  treats,  and  the  numerous  valuable 
observations — pathological  as  well  as  practical — dispersed  throughout  the  pages  of  the  medical 
journals  of  Europe  and  America,  he  has,  nevertheless,  relied  chiefly  upon  his  own  observations  and 
experience,  acquired  during  a  long  and  somewhat  extensive  practice,  and  under  circumstances  pe- 
culiarly well  adapted  for  the  clinical  study  of  the  diseases  of  early  life. 

Every  species  of  hypothetical  reasoning  has,  as  much  as  possible,  been  avoided.  The  author  has 
endeavored  throughout  the  work  to  confine  himself  to  a  simple  statement  of  well-ascertained  patho- 
logical facts,  and  plain  therapeutical  directions — his  chief  desire  being  to  render  it  what  its  title 
imports  it  to  be,  A  PRACTICAL  TREATISE  ON  THE  DISEASES  OF  CHILDREN. 

We  feel  assured  from  actual  experience  that  no 
physician's  library  can  be  complete  without  a  copy 
of  this  work. — N.  Y.  Journal  of  Medicine. 

A  veritable  psediatric  encyclopaedia,  and  an  honor 
to  American  medical  literature.— Ohio  Medical  and 
Surgical  Journal. 

We  feel  persuaded  that  the  American  medical  pro- 
fession will  soon  regard  it  not  only  as  a  very  good, 
but  as  the  VERY  BKST  "Practical  Treatise  on  the 
Diseases  of  Children." — American  Medical  Journal. 


Dr.  Condie:s  scholarship,  acumen,  industry,  and 
practical  sense  are  manifested  in  this,  as  in  all  his 
numerous  contributions  to  science. — Dr.  Holmes's 
Report  to  the  American  Medical  Association. 

Taken  as  a  whole,  in  our  judgment,  Dr.  Condie's 
Treatise  is  the  one  from  the  perusal  of  which  the 
practitioner  in  this  country  will  rise  with  the  great- 
est satisfaction  — Western  Journal  of  Medicine  and 
Surgery. 

One  of  the  best  works  upon  the  Diseases  of  Chil- 
dren in  the  English  language. — Western  Lancet. 

Perhaps  the  most  full  and  complete  work  now  be- 
fore the  profession  of  the  United  States ;  indeed,  we 
may  say  in  the  English  language.  It  is  vastly  supe- 
rior to  most  of  its  predecessors. — Transylvania  Med. 
Journal. 


We  pronounced  the  first  edition  to  he  the  bes-i 
work  on  the  diseases  of  children  in  the  English 
language,  and,  notwithstanding  all  that  has  heem 
published,  we  still  regard  it  in  that  light.— Medical 
Examiner. 


COOPER  (BRANSBY  B.),  F.  R.  S., 

Senior  Surgeon  to  Guy's  Hospital,  &c. 

LECTURES  ON  THE   PRINCIPLES  AND   PRACTICE   OF   SURGERY. 

In  one  very  large  octavo  volume,  of  750  pages.    (Lately  Issued.) 

For  twenty-five  years  Mr.  Bransby  Cooper  has  I  Cooper's  Lectures  as  a  most  valuable  addition  to 
been  surgeon  to  Guy's  Hospital;   and  the  volume  |  our  surgical  literature,  and  one  which  cannot  fail 


before  us  may  be  said  to  consist  of  an  account  of 
the  results  of  his  surgical  experience  during  that 
long  period.  We  cordially  recommend  Mr.  Bransby 


to  be  of  service  both  to  students  and  to  those  who 
are  actively  engaged  in  the  practice  of  their  profes- 
sion.— The  Lancet, 


COOPER  (SIR  ASTLEY   P.),   F.  R.  S.,  &c. 
A  TREATISE  ON  DISLOCATIONS  AND  FRACTURES  OF  THE  JOINTS, 

Edited  by  BRANSBY  B.  COOPER,  F.  R.  S.,  &c.  With  additional  Observations  by  Prof.  J.  C. 
WARREN.  A  new  American  edition.  In  one  handsome  octavo  volume,  with  numerous  illustra- 
tions on  wood. 


BY   THE   SAME   AUTHOR. 


ON  THE  ANATOMY  AND  TREATMENT  OF  ABDOMINAL  HERNIA. 

One  large  volume,  imperial  8vo.,  with  over  130  lithographic  figures. 


BY   THE   SAME   AUTHOR. 


ON   THE   STRUCTURE   AND  DISEASES   OF  THE  TESTIS,  AND  ON 

THE  THYMUS  GLAND.     One  vol.  imperial  8vo.,  with  177  figures,  on  29  plates. 


BY   THE   SAME   AUTHOR. 

ON  THE  ANATOMY  AND  DISEASES   OF  THE   BREAST,  with  twenty- 
five  Miscellaneous  and  Surgical  Papers.     One  large  volume,  imperial  8vo.,  with  252  figures,  on 
36  plates. 
These  last  three  volumes  complete  the  surgical  writings  of  Sir  Astley  Cooper.    They  are  very 

handsomely  printed,  with  a  large  number  oi  lithographic  plates,  executed  in  the  best  style,  and  are 

presented  at  exceedingly  low  priees, 


AND    SCIENTIFIC 


CHURCHILL  (FLEETWOOD),  M.  D.,  M.  R.  I.  A. 
ON  THE  THEORY  AND  PRACTICE  OF  MIDWIFERY.  A  new  American, 

from  the  last  and  improved  English  edition.  Edited,  with  Notes  and  Additions,  by  D.  FRANCIS 
CONDIE,  M.  D.,  author  of  a  "Practical  Treatise  on  the  Diseases  of  Children,"  &c.  With  139 
illustrations.  In  one  very  handsome  octavo  volume,  pp.  510.  (Lately  Issued.} 


To  bestow  praise  on  a  book  that  has  received  such 
marked  approbation  would  be  superfluous.  We  need 
only  say,  therefore,  that  if  the  first  edition  was 
thought  worthy  of  a  favorable  reception  by  the 
medical  public,  we  can  confidently  affirm  that  this 
wiii  be  found  much  more  so.  The  lecturer,  $he 
practitioner,  and  the  student,  may  all  have  recourse 
to  its  pages,  and  derive  from  their  perusal  much  in- 
terest and  instruction  in  everything  relating  to  theo- 
retical and  practical  midwifery.— Dublin  quarterly 
Journal  of  Medical  Science. 

A.  work  of  very  great  merit,  and  such  as  we  can 
confidently  recommend  to  the  study  of  every  obste- 
tric practitioner.— London  Medical  Gazette. 

This  is  certainly  the  most  perfect  system  extant. 
£t  is  the  best  adapted  for  the  purposes  of  a  text- 
book, and  that  which  he  whose  necessities  confine 
him  to  one  book,  should  select  in  preference  to  all 
others.— Southern  Medical  and  Surgical  Journal. 

The  most  popular  work  on  midwifery  ever  issued 
from  the  American pre«s. — Charleston  Med.  Journal. 

Were  we  reduced  to  the  necessity  of  having  but 
ene  work  on  midwifery,  and  permitted  to  choose, 
we  would  unhesitatingly  take  Churchill.— Western 
Med.  and  Surg.  Journal. 

It  is  impossible  to  conceive  a  more  useful  aad 
elegant  manual  than  Dr.  Churchill's  Practice  of 
Midwifery. — Provincial  Medical  Journal. 

Certainly,  in  our  opinion,  the  very  best  work  on 
the  subject  which  exists.— 2V.  Y.  Annalist. 


No  work  holds  a  higher  position,  or  is  more  de- 
serving of  being  placed  in  the  hands  of  the  tyro, 
the  advanced  student,  or  the  practitioner.— Medical 
Examiner. 

Previous  editions,  under  the  editorial  supervisioa 
of  Prof  R.  M.  Huston,  have  been  received  with 
marked  favor,  and  they  deserved  it;  but  this,  re- 
printed from  a  very  late  Dublin  edition,  carefully 
revised  and  brought  up  by  the  author  to  the  present 
time,  does  present  an  unusually  accurate  and  able 
exposition  of  every  important  particular  embraced 
in  the  department  of  midwifery.  *  *  The  clearness, 
directness,  and  precision  of  its  teachings,  together 
with  the  great  amount  of  statistical  research  which 
its  text  exhibits,  have  served  to  place  it  already  ia 
the  foremost  rank  of  works  in  this  department  of  re- 
medial science. — N.  O.  Med.  and  Surg.  Journal. 

In  our  opinion,  it  forms  one  of  the  best  if  not  th« 
very  best  text-book  and  epitome  of  obstetric  science 
which  we  at  present  possess  in  the  English  lan- 
guage.— Monthly  Journal  of  Medical  Science. 

The  clearness  and  precision  of  style  in  which  it  is 
written,  and  the  great  amount  of  statistical  research 
which  it  contains,  have  served  to  place  it  in  the  first 
rank  of  works  in  this  department  of  medical  science. 
—2V.  Y.  Journal  of  Medicine. 

Few  treatises  will  be  found  better  adapted  a«  a. 
text-book  for  the  student,  or  as  a  manual  for  the 
frequent  consultation  of  the  young  practitioner. — 
American  Medical  Journal. 


BY   THE  SAME  AUTHOR. 


ON  THE  DISEASES  OF  INFANTS  AND  CHILDREN. 

handsome  volume  of  over  600  pages. 


In  one  large  and 


We  regard  this  volume  as  possessing  more  claims 
to  completeness  than  any  other  of  the  kind  with 
which  we  are  acquainted.  Most  cordially  and  earn- 
estly, therefore,  do  we  commend  it  to  our  profession- 
al brethren,  and  we  feel  assured  that  the  stamp  of 
Cheir  approbation  will  in  due  time  be  impressed  upon 
it.  After  an  attentive  perusal  of  its  contents,  we 
hesitate  not  to  say,  that  it  is  one  of  the  most  com- 
prehensive ever  written  upon  the  diseases  of  chil- 
dren, and  that,  for  copiousness  of  reference,  extent  of 
research,  and  perspicuity  of  detail,  it  is  scarcely  to 
he  equalled,  and  not  to  be  excelled,  ia  any  lan- 
guage.— Dublin  Quarterly  Journal. 

After  this  meagre,  and  we  know,  very  imperfect 
aotice  of  Dr.  Churchill's  work,  we  shall  conclude 
by  saying,  that  it  is  one  that  cannot  fail  from  its  co- 
piousness, extensive  research,  and  general  accuracy, 
to  exalt  still  higher  the  reputation  of  the  author  in 
this  country.  The  American  reader  will  be  particu- 
larly pleased  to  find  that  Dr.  Churchill  has  done  full 
justice  throughout  his  work  to  the  various  American 
authors  on  this  subject.  The  names  of  Dewees, 
Eberle,  Condie,  and  Stewart,  occur  on  nearly  every 
page,  and  these  authors  are  constantly  referred  to  Ivy 
the  author  in  terms  of  the  highest  praise,  and  with 
the  most  liberal  courtesy. — The  Medical  Examiner. 


The  present  volume  will  sustain  the  reputation 
acquired  by  the  author  from  his  previous  works. 
The  reader  will  find  in  it  full  and  judicious  direc- 
tions for  the  management  of  infants  at  birth,  and  a. 
compendious,  but  clear  account  of  the  diseases  to 
which  children  are  liable,  and  the  most  successful 
mode  of  treating  them.  We  must  not  close  this  no- 
tice without  calling  attention  to  the  author's  style, 
which  is  perspicuous  and  polished  to  a  degree,  we 
regret  to  say,  not  generally  characteristic  of  medical 
works.  "VVe  recommend  the  work  of  Dr.  Churchill 
most  cordially,  both  to  students  and  practitioners, 
as  a  valuable  and  reliable  guide  in  the  treatment  of 
the  diseases  of  children. — Am.  Journ.  of  the  Med. 
Sciences. 

We  know  of  no  work  on  this  department  of  Prac- 
tical Medicine  which  presents  so  candid  and  unpre- 
judiced a  statement  or  posting  up  of  our  actual 
knowledge  as  this. — 2V.  Y.  Journal  of  Medicine. 

Its  claims  to  merit  both  as  a  scientific  and  practi- 
cal work,  are  of  the  highest  order.  Whilst  we 
would  not  elevate  it  above  every  other  treatise  on 
the  same  subject,  we  certainly  believe  that  very  few 
are  equal  to  it,  and  none  superior. — Southern  Med. 
and  Surgical  Journal. 


BY   THE   SAME   AUTHOR. 

ESSAYS  ON  THE  PUERPERAL  FEVER,  AND  OTHER  DISEASES  PE- 
CULIAR TO  WOMEN.  Selected  from  the  writings  of  British  Authors  previous  to  the  close  ot 
the  Eighteenth  Century.  In  one  neat  octavo  volume,  of  about  four  hundred  and  fifty  pages. 

To  these  papers  Dr.  Churchill  has  appended  notes,  demies  of  that  disease.     The  whole  forms  a  very 

embodying  whatever  information  has  been  laid  be-  valuable  collection  of  papers,  by  professional  writers 

fore  the  profession  since  their  authors'  time.    He  has  of  eminence,  on  some  of  the  most  important  accidents 

also  prefixed  to  the  Essays  on   Puerperal   Fever,  to  which  the  puerperal  female  is  liable. American 

which  occupy  the  larger  portion  of  the  volume,  an  Journal  of  Medical  Sciences. 
interesting  historical  sketch  of  the  principal  epi- 


10 


&   LEA'S    MEDICAL 


CHURCHILL  (FLEETWOOD),    M.  D.,  M .  R.  I .  A.,    &c. 

ON  THE  DISEASES  OF  WOMEN;  includiDg  those  of  Pregnancy  and  Child- 
bed.  A  new  American  edition,  revised  by  the  Author.  With  Notes  and  Additions,  by  D  FRAN- 
CIS CONDIE,  M.  D.,  author  of  "A  Practical  Treatise  on  the  Diseases  of  Children."  In  one  large 
and  handsome  octavo  volume,  with  wood-cuts,  pp.  684.  (Just  Issued.) 

From  the  Author's  Preface. 

In  reviewing-  this  edition,  at  the  request  of  my  American  publishers,  I  have  inserted  several  new 
sections  and  chapters,  and  I  have  added,  I  believe,  all  the  information  we  have  derived  from  recent 
researches ;  in  addition  to  which  the  publishers  have  been  fortunate  enough  to  secure  the  services 
of  an  able  and  highly  esteemed  editor  in  Dr.  Condie. 


We  now  regretfully  take  leave  of  Dr.  Churchill's 
book.  Had  our  typographical  limits  permitted,  we 
should  gladly  have  borrowed  more  from  its  richly 
stored  pages.  In  conclusion,  we  heartily  recom- 
mend it  to  the  profession,  and  would  at  the  same 
time  express  our  firm  conviction  that  it  will  not  only 
add  to  the  reputation  of  its  author,  but  will  prove  a 
work  of  great  and  extensive  utility  to  obstetric 
practitioners. — Dublin  Medical  Press. 

Former  editions  of  this  work  have  been  noticed  in 
previous  numbers  of  the  Journal.  The  sentiments  of 
high  commendation  expressed  in  those  notices,  have 
only  to  be  repeated  in  this ;  not  from  the  fact  that 
the  profession  at  large  are  not  aware  of  the  high 
merits  which  this  work  really  possesses,  but  from  a 
desire  to  see  the  principles  and  doctrines  therein 
contained  more  generally  recognized,  and  more  uni- 
versally carried  out  in  practice. — N.  Y.  Journal  of 
Medicine . 

We  know  of  no  author  who  deserves  that  appro- 
bation, on  "the  diseases  of  females,"  to  the  same 
extent  that  Dr.  Churchill  does.  His,  indeed,  is  the 
only  thorough  treatise  we  know  of  on  the  subject ; 
and  it  may  be  commended  to  practitioners  and  stu- 
dents as  a  masterpiece  in  its  particular  department. 
The  former  editions  of  this  work  have  been  com- 
mended strongly  in  this  journal,  and  they  have  won 
their  way  to  an  extended,  and  a  well-deserved  popu- 


larity. This  fifth  edition,  before  us.  is  well  calcu- 
lated to  maintain  Dr.  Churchill's  high  reputation. 
It  was  revised  and  enlarged  by  the  author,  for  hia 
American  publishers,  and  it  seems  to  us  that  there  is 
scarcely  any  species  of  desirable  information  on  its 
subjects  that  may  not  be  found  in  this  work. — Th& 
Western  Journal  of  Medicine  and  Surgery. 

We  are  gratified  to  announce  a  new  and  revised 
edition  of  Dr.  Churchill's  valuable  work  on  the  dis- 
eases of  females  We  have  ever  regarded  it  as  one 
of  the  very  best  works  on  the  subjects  embraced 
within  its  scope,  in  the  English  language;  and  th« 
present  edition,  enlarged  and  revised  by  the  author, 
renders  it  still  more  entitled  to  the  confidence  of  the 
profession.  The  valuable  notes  of  Prof.  Huston 
have  been  retained,  and  contribute,  in  110  small  de- 
gree, to  enhance  the  value  of  the  work.  It  is  a 
source  of  congratulation  that  the  publishers  have 
permitted  the  author  to  be,  in  this  instance,  his 
own  editor,  thus  securing  all  the  revision  which 
an  author  alone  is  capable  of  making. — The  Western 
Lancet. 

As  a  comprehensive  manual  for  students,  or  a 
work  of  reference  for  practitioners,  we  only  speak 
with  common  justice  when  we  say  that  it  surpasses 
any  other  that  has  ever  issued  on  the  same  sub- 
ject from  the  British  press. — The  Dublin  Quarterly 
Journal. 


DEyVEES  (W.    P.),   M.D.,    &c. 
A   COMPREHENSIVE   SYSTEM  OF   MIDWIFERY.     Illustrated  by  occa- 

sional  Cases  and  many  Engravings.     Twelfth  edition,  with  the  Author's  last  Improvements  and 
Corrections.     In  one  octavo  volume,  of  600  pages.     (Just  Issued.) 

BY   THE   SAME   AUTHOR. 

A  TREATISE  ON  THE  PHYSICAL  AND  MEDICAL  TREATMENT  OF 

CHILDREN.     Tenth  edition.     In  one  volume,  octavo,  548  pages.     (Just  Issued.) 


BY   THE    SAME   AUTHOR. 


A  TREATISE  ON   THE  DISEASES   OF   FEMALES.     Tenth   edition. 

one  volume,  octavo,  532  pages,  with  plates.     (Just  Issued.) 


In 


DICKSON   (PROFESSOR   S.    H.>,    M.D. 
ESSAYS  ON  LIFE,  SLEEP,  PAIN,   INTELLECTION,   HYGIENE,   AND 

DEATH.     In  one  very  handsome  volume,  royal  12mo. 


DANA   (JAMES    D). 
ZOOPHYTES  AND  CORALS.     In  one  volume,  imperial  quarto,  extra  cloth, 

with  wood-cuts. 

ALSO, 

AN  ATLAS  TO  THE  ABOVE,  one  volume,  imperial  folio,  with  sixty-one  mag- 

nificent  plates,  colored  after  nature.    Bound  in  half  morocco. 


ON    THE    STRUCTURE    AND    CLASSIFICATION    OF    ZOOPHYTES 

Sold  separate,  one  vol.,  cloth. 


DE    LA    BECHE   (SIR    HENRY    T.),   F.  R.  S.,  &c. 

THE  GEOLOGICAL  OBSERVER.     In  one  very  large  and  handsome  octavo 
volume,  of  700  pages.    With  over  three  hundred  wood-cuts.     (Lately  Issued.) 


AND   SCIENTIFIC    PUBLICATIONS. 


11 


DRUITT   (ROBERT),   M.R.  C.S.,   &c. 
THE  PRINCIPLES  AND  PRACTICE   OF  MODERN   SURGERY.     A  new 

American,  from  the  improved  London  edition.  Edited  by  F.  W.  SARGENT,  M.  D.,  author  of 
"Minor  Surgery,"  &c.  Illustrated  with  one  hundred  and"  ninety-three  wood-engravings.  In 
one  very  handsomely  printed  octavo  volume,  of  576  large  pages. 


Dr.  Druitt's  researches  into  the  literature  of  his 
subject  have  been  not  only  extensive,  but  well  di- 
rected ;  the  most  discordant  authors  are  fairly  and 
impartially  quoted,  and,  while  due  credit  is  given 
to  each,  their  respective  merits  are  weighed  with 
an  unprejudiced  hand.  The  grain  of  wheat  is  pre- 
served, and  the  chaff  is  unmercifully  stripped  off. 
The  arrangement  is  simple  and  philosophical,  and 
the  style,  though  clear  and  interesting,  is  so  precise, 
that  the  book  contains  more  information  condensed 
into  a  few  words  than  any  other  surgical  work  with 
which  we  are  acquainted. — London  Medical  Times 
and  Gazette,  February  IS,  1S54. 

No  work,  in  our  opinion,  equals  it  in  presenting 
BO  much  valuable  surgical  matter  in  so  small  a 
compass. — St.  Louis  Med.  and  Surgical  Journal. 

Druitt's  Surgery  is  too  well  known  to  the  Ameri- 
can medical  profession  to  require  its  announcement 
anywhere.  Probably  no  work  of  the  kind  has  ever 
been  more  cordially  received  and  extensively  circu- 
lated than  this.  The  fact  that  it  comprehend*  in  a 
comparatively  small  compass,  all  the  essential  ele- 
ments of  theoretical  and  practical  Surgery — that  it 
is  found  to  contain  reliable  and  authentic  informa- 
tion on  the  nature' and  treatment  of  nearly  all  surgi- 
cal affections — is  a  sufficient  reason  for  the  liberal 
patronage  it  has  obtained.  The  editor,  Dr.  F.  W. 
Sargent,  has  contributed  much  to  enhance  the  value 
of  the  work,  by  such  American  improvements  as  are 
calculated  more  perfectly  to  adapt  it  to  our  own 
views  and  practice  in  this  country.  It  abounds 
everywhere  with  spirited  and  life-like  illustrations, 
which  to  the  young  surgeon,  especially,  are  of  no 
minor  consideration.  Every  medical  man  frequently 
needs  just  such  a  work  as  this,  for  immediate  refe- 
rence in  moments  of  sudden  emergency,  when  he  has 
not  time  to  consult  more  elaborate  treatises.— The 
Ohio  Medical  and  Surgical  Journal. 

The  author  has  evidently  ransacked  every  stand- 
r.rd  treatise  of  ancient  and  modern  times,  and  all  that 


is  really  practically  useful  at  the  bedside  will  be 
found  in  a  form  at  once  clear,  distinct,  and  interest- 
ing.— Edinburgh  Monthly  Medical  Journal. 

Druitt's  work,  condensed,  systematic,  lucid,  and 
practical  as  it  is,  beyond  most  works  on  Surgery 
accessible  to  the  American  student,  has  had  much 
currency  in  this  country,  and  under  its  present  au- 
spices promises  to  rise  to  yet  higher  favor. — The 
Western  Journal  of  Medicine  and  Surgery. 

The  most  accurate  and  ample  resume  of  the  pre- 
sent state  of  Surgery  that  we  are  acquainted  with. — 
Dublin  Medical  Journal. 

A  better  book  on  the  principles  and  practice  of 
Surgery  as  now  understood  in  England  and  America, 
has  not  been  given  to  the  profession. — Boston  Medi- 
cal  and  Surgical  Journal. 

An  unsurpassable  compendium,  not  only  of  Sur- 
gical, but  of  Medical  Practice. — London  Medical 
Gazette. 

This  work  merits  our  warmest  commendations, 
and  we  strongly  recommend  it  to  young  surgeons  as 
an  admirable  digest  of  the  principles  and  practice  of 
modern  Surgery. — Medical  Gazette. 

It  maybe  said  with  truth  that  the  work  of  Mr. 
Druitt  affords  a  complete,  though  brief  and  con- 
densed view,  of  the  entire  field  of  modern  surgery. 
We  know  of  no  work  on  the  same  subject  having  the 
appearance  of  a  manual,  which  includes  so  many 
topics  of  interest  to  the  surgeon  ;  and  the  terse  man- 
ner in  which  each  has  been  treated  evinces  a  most 
enviable  quality  of  mind  on  the  part  of  the  author, 
who  seems  to  have  an  innate  power  of  searching 
out  and  grasping  the  leading  facts  and  features  of 
the  most  elaborate  productions  of  the  pen.  It  is  a 
useful  handbook  for  the  practitioner,  and  we  should 
deem  a  teacher  of  surgery  unpardonable  who  did  not 
recommend  it  to  his  pupils.  In  our  own  opinion,  it 
is  admirably  adapted  to  the  wants  of  the  student. — 
Provincial  Medical  and  Surgical  Journal. 


DUNGL1SON,    FORBES,   TWEED1E,    AND   CONOLLY. 
THE  CYCLOPEDIA  OF  PRACTICAL  MEDICINE:  comprising  Treatises  on 

the  Nature  and  Treatment  of  Diseases,  Materia  Mediea,  and  Therapeutics,  Diseases  of  Women 
and  Children,  Medical  Jurisprudence,  &e.  &c.  In  four  large  super  royal  octavo  volumes,  of 
3254  double-columned  pages,  strongly  and  handsomely  bound. 

*jfc*  This  work  contains  no  less  than  four  hundred  and  eighteen  distinct  treatises,  contributed  by 
sbAy-eight  distinguished  physicians. 


The  most  complete  work  on  Practical  Medicine 
extant;  or,  at  least,  in  our  language. — Buffalo 
Medical  and  Surgical  Journal. 

For  reference,  it  is  above  all  price  to  every  prac- 
titioner.— Western  Lancet. 

One  of  the  most  valuable  medical  publications  of 
nhe  day— as  a  work  of  reference  it  is  invaluable.— 
Western  Journal  of  Medicine  and  Surgery. 

It  has  been  to  us,  both  as  learner  and  teacher,  a 
workfor  ready  and  frequent  reference,  one  in  which 
modern  English  medicine  is  exhibited  in  the  most 
advantageous  light. — Medical  Examiner. 

We  rejoice  that  this  work  is  to  be  placed  within 
the  reach  of  the  profession  in  this  country,  it  being 


unquestionably  one  of  very  great  value  to  the  prac- 
titioner. This  estimate  of  it  has  not  been  formed 
from  a  hasty  examination,  but  after  an  intimate  ac- 
quaintance derived  from  frequent  consultation  of  it 
during  the  past  nine  or  ten  years.  The  editors  are 
practitioners  of  established  reputation,  and  the  list 
of  contributors  embraces  many  of  the  most  eminent 
professors  and  teachers  of  London,  Edinburgh,  Dub- 
lin, and  Glasgow.  It  is,  indeed,  the  great  merit  of 
this  work  that  the  principal  articles  have  been  fur- 
nished by  practitioners  who  have  not  only  devoted 
especial  attention  to  the  diseases  about  which  they 
have  written,  but  have  also  enjoyed  opportunities 
for  an  extensive  practical  acquaintance  with  them, 
and  whose  reputation  carries  the  assurance  of  their 
competency  justly  to  appreciate  the  opinions  of 
others,  while  it  stamps  their  own  doctrines  with 
high  and  just  authority. — American  Medical  Journ. 


DUNGLISON    (ROBLEY),    M.D., 

Professor  of  the  Institutes  of  Medicine  in  the  Jefferson  Medical  College,  Philadelphia. 

HUMAN  HEALTH;  or,  the  Influence  of  Atmosphere  and  Locality,  Change  of 
Air  and  Climate,  Seasons,  Food,  Clothing,  Bathing,  Exercise,  Sleep,  &c.  &c.,  on  Healthy  Man; 
constituting  Elements  of  Hygiene.  Second  edition,  with  many  modifications  and  additions.  In 
one  octavo  volume,  of  464  pages. 


12 


BLANCHARD   &    LEA'S   MEDICAL 


DUNGLISON    (ROBLEY),    M.D., 

Professor  of  Institutes  of  Medicine  in  the  Jefferson  Medical  College,  Philadelphia. 

MEDICAL  LEXICON;  a  Dictionary  of  Medical  Science,  containing  a  concise 
Explanation  of  the  various  Subjects  and  Terms  of  Physiology,  Pathology,  Hygiene,  Therapeutics, 
Pharmacology,  Obstetrics,  Medical  Jurisprudence,  &c.  With  the  French  and  other  Synonymes  ; 
Notices  of  Climate  and  of  celebrated  Mineral  Waters;  Formulae  for  various  Officinal,  "Empirical, 
and  Dietetic  Preparations,  etc.  Eleventh  edition,  revised.  In  one  very  thick  octavo  volume,  oi 
over  nine  hundred  large  double-columned  pages,  strongly  bound  in  leather,  with  raised  bands. 
(Just  Issued.) 

Every  successive  edition  of  this  work  bears  the  marks  of  the  industry  of  the  author,  and  of  his 
determination  to  keep  it  fully  on  a  level  with  the  most  advanced  state  of  medical  science.  Thus 
nearly  FIFTEEN  THOUSAND  WORDS  have  been  added  to  it  within  the  last  few  years.  As  a  complete 
Medical  Dictionary,  therefore,  embracing  over  FIFTY  THOUSAND  DEFINITIONS,  in  all  the 
branches  of  the  science,  it  is  presented  as  meriting  a  continuance  of  the  great  favor  and  popularity 
which  have  carried  it,  within  no  very  long  space  of  time,  to  an  eleventh  edition. 

Every  precaution  has  been  taken  in  the  preparation  of  the  present  volume,  to  render  its  mecha- 
nical execution  and  typographical  accuracy  worthy  of  its  extended  reputation  and  universal  use. 
The  very  extensive  additions  have  been  accommodated,  without  materially  increasing  the  bulk  oi 
the  volume  by  the  employment  of  a  small  but  exceedingly  clear  type,  cast  for  this  purpose.  The 
press  has  been  watched  with  great  care,  and  every  effort  used  to  insure  the  verbal  accuracy  so  ne- 
cessary to  a  work  of  this  nature.  The  whole  is  printed  on  fine  white  paper ;  and,  while  thus  exhi- 
biting "in  every  respect  so  great  an  improvement  over  former  issues,  it  is  presented  at  the  original 
exceedingly  low  price. 

valuable  work,  we  directed  the  attention  of  OUT 
readers  to  its  peculiar  merits ;  and  we  need  do 
little  more  than  state,  in  reference  to  the  preseni 
reissue,  that,  notwithstanding  the  large  additions 
previously  made  to  it,  BO  fewer  than  four  thou- 
sand ternis,  not  to  be  found  in  the  preceding  edi- 
tion, are  contained  in  the  volume  before  us.— 
Whilst  it  is  a  wonderful  monument  of  its  author's 


We  welcome  it  cordially ;  it  is  an  admirable  work, 
and  indispensable  to  all  literary  medical  men.  The 
labor  wlrich  has  been  bestowed  upon  it  is  something 
prodigious.  The  work,  however,  has  now  been 
done,"  and  we  are  happy  in  the  thought  that  no  hu- 
man being  will  have  again  to  undertake  the  same 
gigantic  task.  Revised  and  corrected  from  time  to 
time,  Dr.  Dunglison's  "  Medical  Lexicon"  will  last 
for  centuries.— British  and  Foreign  Med.  Chirurg. 
Review,  July,  1853. 

The  fact  that  this  excellent  and  learned  work  has 
passed  through  eight  editions,  and  that  a  ninth  is 
rendered  necessary  by  the  demands  of  the  public, 
affords  a  sufficient  evidence  of  the  general  apprecia- 
tion of  Dr.  Dunglison's  labors  by  the  medical  pro- 
fession in  England  and  America.  It  is  a  book  which 
will  be  of  great  service  to  the  student,  in  teaching 
him  the  meaning  of  all  the  technical  terms  used  in 
reedicine,  and  will  be  of  no  jess  use  to  the  practi- 
tioner who  desires  to  keep  himself  on  a  level  with 
the  advance  of  medical  science. — London  Medical 
Times  and  Gazette. 

In  taking  leave  of  our  author,  we  feel  compelled 
to  confess  that  his  work  bears  evidence  of  almost 
incredible  labor  having  been  bestowed  upon  its  com- 
position.—  Edinburgh  Journal  of  Med.  Sciences, 
Sept.  1853. 

A  miracle  of  labor  and  industry  in  one  who  has 


branch  of  medical  science.  There  could  be  no  more 
useful  book  to  the  student  or  practitioner,  in  the 
present  advancing  age,  than  one  in  which  would  be 
found,  in  addition  to  the  ordinary  meaning  and  deri- 
vation of  medical  terms — so  many  of  which  are  of 
modern  introduction — concise  descriptions  of  their 
explanation  and  employment ;  and  all  this  and  much 
more  is  contained  in  the  volume  before  us.  It  is 
therefore  almost  as  indispensable  to  the  other  learned 
professions  as  to  our  own.  In  fact,  to  ail  who  may 
have  occasion  to  ascertain  the  meaning  of  any  word 
belonging  to  the  many  branches  of  medicine.  From 
a  careful  examination  of  the  present  edition,  we  can 
vouch  for  its  accuracy,  and  for  its  being  brought 
quite  up  to  the  date  of  publication  ;  tlie  author  states 
in  his  preface  that  he  has  added  to  it  about  four  thou- 
sand terms,  which  are  not  to  be  found  in  the  prece- 
ding one.  —  Dublin  Quarterly  Journal  of  Medical 
Sciences. 

On  the  appearance  of  the  last  edition  of   this 


erudition  and  industry,  it  is  also  a  work  of  great 
practical  utility,  as  we  can  testify  from  our  owa 
experience;  for  we  keep  it  constantly  within  our 
reach,  and  make  very  frequent  reference  to  it,, 
nearly  always  finding  in  it  the  information  we  seek. 
—British  and  Foreign  Med.-Chirurg.  Review. 

It  has  the  rare  merit  that  it  certainly  has  no  rival 
in  the  English  language  for  accuracy  and  extent 
of  references.  The  terms  generally  include  short 
physiological  and  pathological  descriptions,  so  that, 
as  the  author  justly  observes,  the  reader  does  not 
possess  in  this  work  a  mere  dictionary,  but  a  book, 
which,  while  it  instructs  him  in  medical  etymo- 
logy, furnishes  him  with  a  large  amount  of  useful 
information.  The  author's  labors  have  been  pro- 
perly appreciated  by  his  own  countrymen  ;  and  we 
can  only  confirm  their  judgment,  by  recommending 
this  most  useful  volume  to  the  notice  of  our  cisat- 
lantic readers.  No  medical  library  will  be  complete 
without  it. — London  Med.  Gazette. 

It  is  certainly  more  complete  and  comprehensive 
than  any  with  which  we  are  acquainted  in  the 
English  language.  Few,  in  fact,  could  be  found 
better  qualified  than  Dr.  Dunglison  for  the  produc- 
tion of  such  a  work.  Learned,  industrious,  per- 
severing, and  accurate,  he  brings  to  the  task  all 
the  peculiar  talents  necessary  for  its  successfu? 


performance; 


liarity  with  the  writing 
"  masters  of  our  art," 


at  the  same  time,  his  fami- 


s of  the  ancient  and  modern 
renders  him  skilful  to  note 

the  exact  usage  of  the  several  terms  of  science, 
and  the  various  modifications  which  medical  term- 
inology has  undergone  with  the  change  of  theo- 
ries or  the  progress  of  improvement.  —  American 
Journal  of  the  Medical  Sciences. 

One  of  the  most  complete  and  copious  known  to 
the  cultivators  of  medical  science.  —  JBosto-n  Med. 
Journal. 

The  most  comprehensive  and  best  English  Dic- 
tionary of  medical,  terms  extaat.  —  Buffalo  Medical 
Journal. 


BY   THE   SAME   AUTHOR. 

THE  PRACTICE  OF  MEDICINE.     A  Treatise  on  Special  Pathology  and  The- 
rapeutics.   Third  Edition.    In  two  large  octavo  volumes,  of  fifteen  hundred  pages. 


Upon  every  topic  embraced  in  the  work  the  latest 
information  will  be  found  carefully  posted  up. — 
Medical  Examiner. 

The  student  of  medicine  will  find,  in  these  two 
elegant  volumes,  a  mine  of  facts,  a  gathering  of 
precepts  and  advice  from  the  world  of  experience, 
that  will  nerve  him  with  courage,  and  faithfully 
direct  him  in  his  efforts  to  relieve  the  physical  suf- 


ferings  of  the  race.  —  Boston  Medical  and  Surgical 
Journal  . 

It  is  certainly  the  most  complete  treatise  of  which 
we  have  any  knowledge.—  Western  Journal  of  Medi- 
cine and  Svtrgery. 

One  of  the  most  elaborate  treatises  of  the  kind 
we  have.—  Southern  Med.  and  Surg.  Journal. 


AND    SCIENTIFIC    PUBLICATIONS 


13 


DUNGLISON    (ROBLEY),    M.D., 

Professor  of  Institutes  of  Medicine  in  the  Jefferson  Medical  College,  Philadelphia. 

HUMAN  PHYSIOLOGY.  Seventh  edition.  Thoroughly  revised  and  exten- 
sively modified  and  enlarged,  with  nearly  five  hundred  illustrations.  In  two  large  and  hand- 
somely printed  octavo  volumes,  containing  nearly  1450  pages. 

It  has  long  sin6e  taken  rank  as  one  of  the  medi-  I  Physiology  in  the  English   language,  and  is  highly 
I  classics  of  our  language.     To  say  that  it  is  by  j  creditable  to  the  author  and  publishers. — Canadian 

Medical  Journal. 

The  most  complete  and  satisfactory  system  of 
Physiology  in  the  English  language. — Amer.  Med. 
Journal. 

The  best  work  of  the  kind  in  the  English  lan- 
guage.— Silliman's  Journal. 

The  most  full  and  complete  sj'stem  of  Physiology 
in  our  language. — Western  Lancet. 


sal 

far  the  best  text-book  of  physiology  ever  published 
in  this  country,  is  but  echoing  the  general  testi- 
mony of  the  profession. — N.  Y.  Journal  of  Medicine. 

There  is  no  single  book  we  would  recommend  to 
the  student  or  physician,  with  greater  confidence 
than  the  present,  because  iu  it  will  be  found  a  mir- 
ror of  almost  every  standard  physiological  work  of 
the  day.  We  most  cordially  recommend  the  work 
to  every  member  of  the  profession,  and  no  student 
should  be  without  it.  It  is  the  completest  work  on 


BY   THE    SAME    AUTHOR.      (Just  Issued.) 

GENERAL    THERAPEUTICS    AND    MATERIA  MEDIC  A;   adapted  for  a 

Medical  Text-book.    Fifth  edition,  much  improved.    With  one  hundred  and  eighty-seven  illus- 
trations.   In  two  large  and  handsomely  printed  octavo  vols.,  of  about  1100  pages. 
The  new  editions  of  the  United  States  Pharmacopeia  and  those  of  London  and  Dublin,  have  ren- 
dered necessary  a  thorough  revision  of  this  work.     In  accomplishing  this  the  author  has  spared  no 
pains  in  rendering  it  a  complete  exponent  of  all  that  is  new  and  reliable,  both  in  the  departments 
of  Therapeutics  and  Materia  Medica.     The  book  has  thus  been  somewhat  enlarged,  and  a  like  im- 
provement will  be  found  in  every  department  of  its  mechanical  execution.     As  a  convenient  texl- 
book  for  the  student,  therefore,  containing  within  a  moderate  compass  a  satisfactory  resume  of  its 
important  subject,  it  is  again  presented  as  even  more  worthy  than  heretofore  of  the  very  great  favor 
which  it  has  received. 

In  this  work  of  Dr.  Dunglison,  we  recognize  the  [  As  a  text-book  for  students,  for  whom  it  is  par- 
same  untiring  industry  in  the  collection  and  em-  ticularly  designed,  we  know  of  none  superior  to 
bodying  of  facts  on  the  several  subjects  of  which  he  it. — St.  Louis  Medical  and  Surgical  Journal. 


It  purports  to  be  a  new  edition,  but  it  is  rather 
a  new  book,  so  greatly  has  it  been  improved,  both 
in  the  amount  and  quality  of  the  matter  which  it 
contains. — N.  O.  Medical  and  Surgical  Journal. 

"We  bespeak  for  this  edition,  from  the  profession, 
an  increase  of  patronage  over  any  of  its  former 
ones,  on  account  of  its  increased  merit.  —  N.  Y. 
Journal  of  Medicine. 


treats,  that  has  heretofore  distinguished  him,  and 
we  cheerfully  point  to  these  volumes,  as  two  of  the 
most  interesting  that  we  know  of.  In  noticing  the 
additions  to  this,  the  fourth  edition,  there  is  very 
little  in  the  periodical  or  annual  literature  of  the 
profession,  published  in  the  interval  which  has 
elapsed  since  the  issue  of  the  first,  that  has  escaped 
the  careful  search  of  the  author.  As  a  book  for 
reference,  it  is  invaluable. — Charleston  Med.  Jour- 
nal and  Review. 

It  may  be  said  to  be  the  work  now  upon  the  sub-        We  consider  this  work  unequalled. — Boston  Med  . 
jects  upon  which  it  treats. —  Western  Lancet.  and  Surg.  Journal. 

BY   THE   SAME   AUTHOR. 

NEW  REMEDIES,  WITH  FORMULAE  FOR  THEIR  ADMINISTRATION. 

Sixth  edition,  with  extensive  Additions.    In  one  very  large  octavo  volume,  of  over  750  pages. 

One  of  the  most  useful  of  the  author's  works. — 
Southern  Medical  and  Surgical  Journal. 

This  well-known  and  standard  book  has  now 
reached  its  sixth  edition,  and  has  been  enlarged  and 
improved  by  the  introduction  of  all  the  recent  gifts 
ip  therapeutics  which  the  last  few  years  have  so 
richly  produced,  including  the  anaesthetic  agents, 
Sec.  This  elaborate  and  useful  volume  should  be 
found  in  every  medical  library,  for  as  a  book  of  re- 
ference, for  physicians,  it  is  unsurpassed  by  any 
other  work  iu  existence,  and  the  double  index  for 


diseases  and  for  remedies,  will  be  found  greatly  to 
enhance  its  value. — New  York  Med.  Gazette. 

The  great  learning  of  the  author,  and  his  remark- 
able industry  in  pushing  his   researches  into  every 


very 


source  whence  information  is  derivable,  hag  enabled 
him  to  throw  together  an  extensive  mass  of  facts 
and  statements,  accompanied  by  full  reference  to 
authorities;  which  last  feature  renders  the  work 
practically  valuable  to  investigators  who  desire  to 
examine  the  original  papers. — The  American  Journal 
of  Pharmacy. 


DURLACHER   (LEWIS). 
A   TREATISE    ON   CORNS,   BUNIONS,   THE    DISEASES    OF    NAILS, 

AND  THE  GENERAL  MANAGEMENT  OF   THE  FEET.    IH  one  12mo.  volume,  cloth. 
pp.  134. 


DE  JONGH  (L.  J.),  M.  D.,  &c. 
THE  THREE  KINDS   OF  COD-LIVER  OIL,  comparatively  considered,  with 

their  Chemical  and  Therapeutic  Properties.  Translated,  with  an  Appendix  and  Cases,  by 
EDWARD  CAREY,  M.  D.  To  which  is  added  an  article  on  the  subject  from  "  Dunglison  on  New 
Remedies."  In  one  smaH  12mo.  volume,  extra  cloth. 


DAY  (GEORGE  E.),  M.  D. 
A  PRACTICAL  TREATISE  ON  THE  DOMESTIC  MANAGEMENT  AND 

MORE  IMPORTANT  DISEASES  OF  ADVANCED   LIFE.     With  an  Appendix  on  a  new 


and  successful  mode  of  treating  Lumbago  and  other  forms  of  Chronic  Rheumatism, 
octavo,  226  pages. 


One  volume, 


14 


BLANCHARD   &   LEA'S   MEDICAL 


ELLIS  (BENJAMIN;,  M.D. 

THE  MEDICAL  FORMULARY :  being  a  Collection  of  Prescriptions,  derived 
from  the  writings  and  practice  of  many  of  the  most  eminent  physicians  of  America  and  Europe. 
Together  with  the  usual  Dietetic  Preparations  and  Antidotes  for  Poisons.  To  which  is  added 
an  Appendix,  on  the  Endermic  use  of  Medicines,  and  on  the  use  of  Ether  and  Chloroform.  The 
whole  accompanied  with  a  few  brief  Pharmaceutic  and  Medical  Observations.  Tenth  edition, 
revised  and  much  extended  by  ROBERT  P.  THOMAS,  M.  D.,  Professor  of  Materia  Medica  in  the 
Philadelphia  College  of  Pharmacy.  In  one  neat  octavo  volume,  of  two  hundred  and  ninety-six 
pages.  (Now  Ready.  Revised  and  enlarged  to  1854.) 

This  work  has  received  a  very  complete  revision  at  the  hands  of  the  editor,  who  has  made  what- 
ever alterations  and  additions  the  progress  of  medical  and  pharmaceutical  science  has  rendered  ad- 
visable, introducing  fully  the  new  remedial  agents,  and  revising  the  whole  by  the  latest  improvements 
of  the  Pharmacopoeia.  To  accommodate  these  additions,  the  size  of  the  page  has  been  increased, 
and  the  volume  itself  considerably  enlarged,  while  every  effort  has  been  made  to  secure  the  typo- 
graphical accuracy  which  has  so'long  merited  the  confidence  of  the  profession. 


After  an  examination  of  the  new  matter  and  the 
alterations,  we  believe  the  reputation  of  the  work 
built  up  by  the  author,  and  the  late  distinguished 
editor,  will  continue  to  flourish  under  the  auspices 
of  the  present  editor,  who  has  the  industry  and  accu- 
racy, tmd,  we  would  say,  conscientiousness  requi- 
site for  the  responsible  task. — American  Journal  of 
Pharmacy,  March,  1854. 


It  will  prove  particularly  useful  to  students  ami 
young  practitioners,  as  the  most  important  prescrip- 
tions employed  in  modern  practice,  which  lie  scat- 
tered through  our  medical  literature,  are  here  col- 
lected and  conveniently  arranged  for  reference. — 
Charleston  Med.  Journal  and  Review. 


ER1CHSEN    (JOHN), 

Professor  of  Surgery  in  University  College,  London,  &c. 

THE  SCIENCE  AND  ART  OF  SURGERY;  BEING  A  TREATISE  ON  SURGICAL 

INJURIES,  DISEASKS,  AND  OPERATIONS.  Edited  by  JOHN  H.  BRINTON,  M.  D.  Illustrated  with 
three  hundred  and  eleven  engravings  on  wood.  In  one  large  and  handsome  octavo  volume,  oi 
over  nine  hundred  closely  printed  pages.  (Now  Ready.) 

This  is  a  new  work,  brought  up  to  May,  1854. 
It  is,  in  our  humble  judgment,  decidedly  the  best 
hook  of  the  kind  in  the  English  language.    Strange 
that  just  such  books  are  notoftener  produced  by  pub- 


lie teachers  of  surgery  in  this  country  and  Great 
Britain.  Indeed,  it  is  a  malterof  great  astonishment, 
but  no  less  true  than  astonishing,  that  of  the  many 
works  on  surgery  republished  in  this  country  within 
1he  last  fifteen  or  twenty  years  as  text-books  for 
medical  stuiients,  this  is  the  only  one,  that  even  ap- 
proximates to  the  fulfilment  of  the  peculiar  wants  of 
youngrneri  jusi  entermgupon  the  study  of  this  branch 
of  the  profession. —  Western  Jour .  of Med.  and  Surgery. 
Embracing,  as  will  be  perceived,  the  whole  surgi- 
cal domain,  and  each  division  of  itself  almost  com- 
plete and  perfect,  each  chapter  full  and  explicit,  each 
subject  faithfully  exhibited,  we  can  only  express  our 
extirnate  of  it  in  the  aggregate.  We  consider  it  an 
excellent  contribution  to  surgery,  as  probably  the 
best  single  volume  now  extant  on  the  subject,  and 
with  great  pleasure  we  add  it  to  our  texi  books  — 
Nashville  Journal  of  Medicine  and  Surgery. 


Its  value  is  greatly  enhanced  by  a  very  copious 
well-arranged  index.  We  regard  this  as  one  of  the 
most  valuable  contributions  to  modern  surgery.  To 
one  entering  his  novitiate  of  practice,  we  regard  it 
the  most  serviceable  guide  which  he  can  consult.  He 
will  find  a  fulness  of  detail  leading  him  through  every 
step  of  the  operation,  and  not  deserting  him  until  ihe 
final  issue  of  the  case  is  decided.  For  the  same  rea- 
son we  recommend  it  to  those  whose  routine  of  prac- 
tice lies  in  such  parts  of  the  country  that  they  mast 
rarely  encounter  cases  requiring  surgical  manage- 
ment.— Stethoscope. 

Prof.  Erichsen's  work,  for  its  size,  has  not  been 
surpassed ;  his  nine  hundred  and  eight  pages,  pro- 
fa*e)y  illustrated,  are  rich  in  physiological,  patholo- 
gical, and  operative  suggestions,  doctrines,  details, 
and  processes;  and  will  prove  a  reliable  resource 
for  information,  both  to  physician  and  surgeon,  in  the 
hour  of  peril.— N.  0.  Med.  and  Surg.  Journal. 


FERGUSSON   (WILLIAM),  F.  R.  S., 

Professor  of  Surgery  in  King's  College,  London,  &e. 

A  SYSTEM  OF  PRACTICAL  SURGERY.     Fourth  American,  from  the  third 

and  enlarged  London  edition.    In  one  large  and  beautifully  printed  octavo  volume,  of  about  seven 
hundred  pages,  with  three  hundred  and  ninety-three  handsome  illustrations.     (Just  Issued.) 


The  most  important  subjects  in  connection  with 
practical  surgery  which  have  been  more  recently 
brought  under  the  notice  of,  and  discussed  by,  the 
surgeons  of  Great  Britain,  are  fully  and  dispassion- 
ately considered  by  Mr.  Fergusson,  and  that  which 
was  before  wanting  has  now  been  supplied,  so  that 
we  can  now  look  upon  it  as  a  work  on  practical  sur- 
gery instead  of  one  on  operative  surgery  alone.  And 
we  think  the  author  has  shown  a  wise  discretion  in 
making  the  additions  on  surgical  disease  which  are 
to  be  found  in  the  present  volume,  and  has  very 
much  enhanced  its  value;  for,  besides  two  elaborate 
chapters  on  the  diseases  of  bones  and  joints,  which 
were  wanting  before,  he  has  headed  each  chief  sec- 
tion of  the  work  by  a  general  description  of  the  sur- 
gical disease  and  injury  of  that  region  of  the  body 
which  is  treated  of  in  each,  prior  to  entering  into  the 
consideration  of  the  more  special  morbid  conditions 
and  their  treatment.  There  is  also,  as  in  former 
editions,  a  sketch  of  the  anatomy  of  particular  re- 
gions. There  was  some  ground  formerly  for  the 
complaint  before  alluded  to,  that  it  dwelt  too  exclu- 


sively on  operative  surgery  ;  but  this  defect  is  now 
removed,  and  the  book  is  more  than  ever  adapted  for 
the  purposes  of  the  practitioner,  whether  he  confines 
himself  more  strictly  to  the  operative  department, 
or  follows  surgery  on  a  more  comprehensive  scale. — 
Medical  Times  and  Gazette. 

No  work  was  ever  written  which  more  nearly 
comprehended  the  necessities  of  the  student  and 
practitioner,  and  was  more  carefully  arranged  to 
that  single  purpose  than  this. — 2V.  Y.  Med.  and  Surg. 
Journal. 

The  addition  of  many  new  pages  makes  this  work 
more  than  ever  indispensable  to  the  student  and  prac- 
titioner.— Ranking's  Abstract. 

Among  the  numerous  works  upon  surgery  pub- 
lished of  late  years,  we  know  of  none  we  value 
more  highly  than  the  one  before  us.  It  is  perhaps 
the  very  best  we  have  for  a  text-book  and  for  ordi- 
nary reference,  being  concise  and  eminently  practi- 
cal.— Sou  them  Med.  and  Surg.  Journal. 


FRICK  (CHARLES),  M.  D. 

RENAL    AFFECTIONS;    their  Diagnosis  and  Pathology. 
One  volume,  royal  12mo.,  extra  cloth. 


With  illustrations. 


AND    SCIENTIFIC    PUBLICATIONS. 


15 


FOWNES  (GEORGE),   PH.  D.,  &c. 

ELEMENTARY  CHEMISTRY;  Theoretical  and  Practical.  With  numerous 
illustrations.  A  new  American,  from  the  last  and  revised  London  edition.  Edited,  with  Addi- 
tions, by  ROBERT  BRIDGES,  M.  D.  In  one  large  royal  12mo.  volume,  of  over  550  pages,  with  181 
wood-cuts,  sheep,  or  extra  cloth.  (Now  Heady.) 

The  lamented  death  of  the  author  has  caused  the  revision  of  this  edition  to  pass  into  the  hands  oi 
ihose  distinguished  chemists,  H.  Bence  Jones  and  A.  W.  Hofmann,  who  have  fully  sustained  its 
reputation  by  the  additions  which  they  have  made,  more  especially  in  the  portion  devoted  to  Organic 
Chemistry,  considerably  increasing  the  size  of  the  volume.  This  labor  has  been  so  thoroughly 
performed,  that  the  American  Editor  has  found  but  little  to  add,  his  notes  consisting  chiefly  of  suck 
matters  as  the  rapid  advance  of  the  science  has  rendered  necessary,  or  of  investigations  which  had 
apparently  been  overlooked  by  the  author's  friends. 

The  volume  is  therefore  again  presented  as  an  exponent  of  the  most  advanced  state  of  chemical 
science,  and  as  not  unworthy  a  continuation  of  the  marked  favor  which  it  has  received  as  an  ele- 
mentary text-book. 


We  know  of  no  better  text-book,  especially  in  the 
difficult  department  of  organic  chemistry,  upon 
which  it  is  particularly  full  and  satisfactory.  We 
would  recommend  it  to  preceptors  as  a  capital 
"office  book"  for  their  students  who  are  beginners 
in  Chemistry.  It  is  copiously  illustrated  with  ex- 
cellent wood-cuts,  and  altogether  admirably  "got 
up."— .ZV.  ^  Medical  Reporter,  March,  1854. 

A  standard  manual,  which  has  long  enjoyed  the 
reputation  of  embodying  much  knowledge  in  a  small 
epace.  The  author  has  achieved  the  difficult  task  of 
condensation  with  masterly  tact.  His  book  is  con- 
cise without  being  dry,  and  brief  without  being  too 
dogmatical  or  general. —  Virginia  Med.  and  Surgical 
Journal. 


The  work  of  Dr.  Fownes  has  long  been  before 
the  public,  and  its  merits  have  been  fully  appreci- 
ated as  the  best  text-book  on  chemistry  now  in 
existence.  We  do  not,  of  course,  place  it  in  a  rank 
superior  to  the  works  of  Brande,  Graham,  Turner, 
Gregory,  or  Gmelin,  but  we  say  that,  as  a  work 
for  students,  it  is  preferable  to  any  of  them. — Lon- 
don Journal  of  Medicine. 

A  work  well  adapted  to  the  wants  of  the  student. 
It  is  an  excellent  exposition  of  the  chief  doctrines 
and  facts  of  modern  chemistry.  The  size  of  the.  work, 
and  still  more  the  condensed  yet  perspicuous  style 
in  which  it  is  written,  absolve  it  from  the  charges 
very  properly  urged  against  most  manuals  termed 
popular. — Edinburgh  Monthly  Journal  of  Melical 
Science. 


GRAHAM   (THOMAS),   F.  R.  S., 
Professor  of  Chemistry  in  University  College,  London,  &c. 

THE  ELEMENTS  OF  CHEMISTRY.     Including  the  application  of  the  Science 

to  the  Arts.    With  numerous  illustrations.    With  Notes  and  Additions,  by  ROBERT  BRIDGES, 
M.  D.,  &e.  &c.     Second  American,  from  the  second  and  enlarged  London  edition 
PART  I.  (Lately  Issued)  large  8vo.,  430  pages,  185  illustrations. 
PART  II.  (Preparing)  to  match. 

The  great  changes  which  the  science  of  chemistry  has  undergone  within  the  last  few  years,  ren- 
der a  new  edition  of  a  treatise  like  the  present,  almost  a  new  work.  The  author  has  devoted 
several  years  to  the  revision  of  his  treatise,  and  has  endeavored  to  embody  in  it  every  fact  and 
inference  of  importance  which  has  been  observed  and  recorded  by  the  great  body  of  chemical 
investigators  who  are  so  rapidly  changing  the  face  of  the  science.  "In  this  manner  the  work  has 
been  greatly  increased  in  size,  and  the  number  of  illustrations  doubled ;  while  the  labors  of  the  editor 
have  been  directed  towards  the  introduction  of  such  matters  as  have  escaped  the  attention  of  the 
author,  or  as  have  arisen  since  the  publication  of  the  first  portion  of  this  edition  in  London,  in  1850. 
Printed  in  handsome  style,  and  at  a  very  low  price,  it  is  therefore  confidently  presented  to  the  pro- 
fession and  the  student  as  a  very  complete  and  thorough  text-book  of  this  important  subject. 

GROSS  (SAMUEL  D.),   M.  D., 

Professor  of  Surgery  in  the  Louisville  Medical  Institute,  &c. 

A  PRACTICAL  TREATISE  ON  THE  DISEASES   AND  INJURIES   OF 

THE  URINARY  ORGANS.     In  one  large  and  beautifully  printed  octavo  volume,  of  over  seven 
hundred  pages.    With  numerous  illustrations. 

this  department  of  art.  We  have,  indeed,  unfeigned 
pleasure  in  congratulating  all  concerned  in  this  pub- 
lication, on  the  result  of  their  labours;  and  expe- 
rience a  feeling  something  like  what  animates  a  long- 
expectant  husbandman,  who,  oftentimes  disappointed 
by  the  produce  of  a  favorite  field,  is  at  last  agree- 
ably surprised  by  a  stately  crop  which  may  bear 
comparison  with  any  of  its  former  rivals.  The 
grounds  of  our  high  appreciation  of  the  work  \vill 
be  obvious  as  we  proceed;  and  we  doubt  not  that, 
the  present  facilities  for  obtaining  American  books 
will  induce  many  of  our  readers  to  verify  our  re- 
commendation by  their  own  perusal  of  it. — British 
and  Foreign  Medico-Chirurgical  Review. 


A  volume  replete  with  truths  and  principles  of  the 
utmost  value  in  the  investigation  of  these  diseases. — 
American  Medical  Journal . 

Dr.  Gross  has  brought  all  his  learning,  experi- 
ence, tact,  and  judgment  to  the  task,  and  has  pro- 
duced a  work  worthy  of  his  high  reputation.  We 
feel  perfectly  safe  in  recommending  it  to  our  read- 
ers as  a  monograph  unequalled  in  interest  and 
practical  value  by  any  other  on  the  subject  in  our 
language. — Western  Journal  of  Med.  and  Surg. 

It  hns  remained  for  an  American  writer  to  wipe 
away  this  reproach  ;  and  so  completely  has  the  task 
been  fulfilled,  that  we  venture  to  predict  for  Dr. 
Gross's  treatise  a  permanent  place  in  the  literature 
of  surgery,  worthy  to  rank  with  the  best  works  of 


Whoever  will  peruse  the  vast  amount  of  valuable 

the  present  age.  Not  merely  is  the  matter  good,  practical  information  it  contains,  and  which  we 
but  the  getting  up  of  the  volume  is  most  creditable  !  have  been  unable  even  to  notice,  will,  we  think, 
to  transatlantic  enterprise;  the  paper  and  print  !  agree  with  us,  that  there  is  no  work  in  the  Eno-]ish 
would  docredittoa  first-rate  London  establishment;  language  which  can  make  any  just  pretensions  to 
and  the  numerous  wood-cuts  which  illustrate  it,  de-  ;  be  its  equal.— N.  Y.  Journal  of  Medicine. 
monstrate  that  America  is  making  rapid  advances  in  i 

BY  THE  SAME  AUTHOR.     (Now  Ready.) 

A  PRACTICAL  TREATISE  ON  FOREIGN  BODIES  IN  THE  AIR-PAS- 
SAGES.   In  one  handsome  octavo  volume,  with  illustrations. 

BY  THE  SAME  AUTHOR.     (Preparing.) 

A  SYSTEM  OF  SURGERY;  Diagnostic,  Pathological,  Therapeutic,  and  Opera- 
tive.   With  very  numerous  engravings  on  wood. 


16 


BLANCHARD    &    LEA'S   MEDICAL 


GRIFFITH  (ROBERT  E.),  M.  D.,  &c. 

A  UNIVERSAL  FORMULARY,  containing  the  methods  of  Preparing  and  Ad- 
ministering Officinal  and  other  Medicines.  The  whole  adapted  to  Physicians  and  Pharmaceu- 
tists. SECOND  EDITION,  thoroughly  revised,  with  numerous  additions,  by  ROBERT  P.  THOMAS, 
M.  D.,  Professor  of  Materia  Medica  in  the  Philadelphia  College  of  Pharmacy.  In  one  large  ami 
handsome  octavo  volume,  of  over  six  hundred  pages,  double  columns.  (Just  Issued.) 

The  speedy  exhaustion  of  a  large  edition,  and  the  demand  for  a  second,  sufficiently  show  the  posi- 
tion which  this  work  has  so  rapidly  attained  as  an  authoritative  and  convenient  work  of  reference  for 
the  physician  and  pharmaceutist.  The  opportunity  thus  afforded  for  its  improvement  has  not  been 
neglected.  In  its  revision,  Professor  Thomas  (to  whom  this  task  has  been  confided  inconsequence 
of  the  death  of  the  author),  has  spared  no  labor,  in  the  hope  of  rendering  it  the  most  complete  and 
correct  work  on  the  subject  as  yet  presented  to  the  profession  All  the  newly  introduced  articles 
of  the  Materia  Medica  have  been  inserted,  such  formulae  as  had  escaped  the  attention  of  the  author 
have  been  added,  and  the  whole  has  been  most  carefully  read  and  examined,  to  insure  the  absolute 
correctness,  so  indispensable  in  a  work  of  this  nature.  The  amount  of  these  additions  may  be  esti- 
mated from  the  fact  that  not  only  has  the  page  been  considerably  enlarged,  but  the  volume  has  also 
been  increased  by  about  fifty  pages,  while  the  arrangement  of  the  formulae  and  the  general  typo- 
graphical execution  will  be  found  to  have  undergone  great  improvement.  To  the  practitioner,  its 
copious  collection  of  all  the  forms  and  combinations  of  the  articles  of  the  Pharmacopoeia  render  it 
an  invaluable  book  of  reference,  while  its  very  complete  embodiment  of  officinal  preparations  of  aH 
kinds,  derived  from  all  sources,  American,  English,  and  Continental,  make  it  an  indispensable  assist-' 
tant  to  the  apothecary. 

It  was  a  work  requiring  much  perseverance,  and 
wben  published  was  looked  upon  as  by  far  the  best 
work  of  its  kind  that  had  issued  from  the  American 
press,  being  free  of  much  of  the  trashy,  and  embrac- 
ing most  of  the  non-officinal  formulae  used  or  known 
in  American,  English,  or  French  practice,  arranged 
under  the  heads  of  the  several  constituent  drugs,  plac- 
ing the  receipt  under  its  more  important  constituent. 
Prof  Thoma*  has  certainly  "improved,"  as  well  as 
added  io  this  Formulary,  and  has  rendered  it  addition- 
ally deserving  of  the  confidence  of  pharmaceutists 


and  physicians. — American  Journal  of  Pharmacy. 

\Ve  are  happy  to  announce  a  new  and  improved 
edition  of  this,  one  of  the  most  valuable  and  useful 
works  that  have  emanated  from  an  American  pen. 
It  would  do  credit  to  any  country,  and  will  be  found 
of  daily  usefulness  to  practitioners  of  medicine;  it  is 
better  adapted  to  their  purposes  than  the  dispensato- 
ries.— Southern  Med.  and  Surg.  Journal. 

A  new  edition  of  ihis  well-known  work,  edited  by 
R.  P.  Thomas,  M.  D.,  affords  occasion  for  renewing 
our  commendation  of  so  useful  a  handbook,  which 
ought  to  be  universally  studied  by  medical  men  of 
every  class,  and  made  use  of  by  way  of  reference  by 
office  pupils,  as  a  standard  authority.  It  has  been 
much  enlarged,  and  now  condenses  a  vast  amount 
of  needful  and  necessary  knowledge  in  small  com- 
pass. The  more  of  such  hooks  the  belter  for  the  pro- 
fession and  the  public.—  N.  Y.  Med.  Gazette. 


It  is  one  of  the  mo^t  usefil  books  a  country  practi- 
tioner can  possibly  have  in  his  possession. — Mtdical 
Chronicle. 

The  amount  of  useful,  every-day  matter,  for  a  prac- 
ticing physician,  is  really  immense. — Boston  Mtd. 
and  Surg.  Journal. 

This  is  a  work  of  six  hundred  and  fifty  one  pages, 
embracing  all  on  the  subject  of  preparing  and  admi- 
nistering medicines  that  can  be  desired  by  the  physi- 
cian and  pharmaceutist. —  Western  Lancet. 


In  short,  it  is  a  full  and  complete  work  of  the  kind, 
and  should  be  in  the  hands  of  every  physician  and 
apothecary. —  O.  Med.  and  Surg.  Journal 

We  predict  a  great  sale  for  this  work,  and  we  espe- 
cially recommend  it  to  all  medical  teachers. — Rich- 
mond Stethoscope. 

This  edition  of  Dr.  Griffith's  work  has  been  greatly 
improved  by  the  revision  and  ample  additions  of  Dr. 
Thomas,  and  is  now,  we  believe,  one  of  the  most 
complete  works  of  its  kind  in  any  language.  The 
additions  amount  to  about  seventy  pages,  and  no 
ettort  has  been  spared  to  include  in  them  all  the  re- 
cent improvement  which  have  bfcn  published  in 
medical  journals,  and  systematic  treatises.  A  work 
of  this  kind  appears  to  us  indispensable  to  the  physi- 
cian, and  there  is  none  we  can  more  cordially  recom- 
mend.—  N.  Y.  Journal  of  Medicine. 


BY   THE   SAME   AUTHOR. 


MEDICAL  BOTANY ;  or,  a  Description  of  all  the  more  important  Plants  used 
in  Medicine,  and  of  their  Properties,  Uses,  and  Modes  of  Administration.    In  or 


volume,  of  704  pages,  handsomely  printed,  with  nearly  350  illustrations  on  wood. 


one  large  octavo 


GLUGE  (GOTTLIEB),   M.D., 

Professor  of  Physiology  and  Pathological  Anatomy  in  the  University  of  Brussels,  &c. 

AN  ATLAS   OF   PATHOLOGICAL   HISTOLOGY.     Translated,  with  Notes 

and  Additions,  by  JOSEPH  LEIDY,  M.  D.,  Professor  of  Anatomy  in  the  University  of  Pennsylva- 
nia.    In  one  volume,  very  large  imperial  quarto,  with  three  hundred  and  twenty  figures,  plain 
and  colored,  on  twelve  copperplates. 
This  being,  as  far  as  we  know,  the  only  work  in 

Avhieh  pathological  histology  is  separately  treated 

of  in  a  comprehensive  manner,  it  will,  we  think,  for 

this  reason,  be  of  infinite  service  to  those  who  desire 


to  investigate  the  subject  systematically,  and  who 
have  felt  the  difficulty  of  arranging  in  their  mind 


the  unconnected  observations  of  a  great  number  of 
authors.  The  development  of  the  morbid  tissues, 
and  the  formation  of  abnormal  products,  may  now 
be  followed  and  studied  with  the  same  ease  and 
satisfaction  as  the  best  arranged  system  of  phy- 
siology.— American  Med.  Journal. 


GREGORY  (WILLIAM),   F.  R.  S.  E., 

Professor  of  Chemistry  in  the  University  of  Edinburgh,  &c. 

LETTERS    TO  A  CANDID    INQUIRER    ON    ANIMAL    MAGNETISM. 

In  one  neat  volume,  royal  12mo.,  extra  cloth. 


GARDNER  (D.  PEREIRA),  M .  D. 

MEDICAL  CHEMISTRY,  for  the  use  of  Students  and  the  Profession :  being  a 
Manual  of  the  Science,  with  its  Applications  to  Toxicology,  Physiology,  Therapeutics,  Hygiene, 
&c.  In  one  handsome  royal  12mo.  volume,  with  illustrations. 


AND    SCIENTIFIC    PUBLICATIONS.  17 

HASSE  (C.  E.),    M.  D. 

AN  ANATOMICAL  DESCRIPTION  OF  THE  DISEASES  OF  RESPIRA- 
TION AND  CIRCULATION.     Translated  and  Edited  by  SWAINE.     In  one  volume,  octavo. 

HARRISON  (JOHN),   M.  D. 
AN   ESSAY  TOWARDS   A   CORRECT  THEORY  OF   THE  NERVOUS 

SYSTEM.     In  one  octavo  volume,  292  pages. 

HUNTER  (JOHN). 
TREATISE  ON  THE  VENEREAL  DISEASE.     With  copious  Additions,  by 

DR.  PH.  RICORD,  Surgeon  to  the  Venereal  Hospital  of  Paris.     Edited,  with  additional  Notes,  by 
F.  J.  BUMSTEAD,  M.  D.     In  one  octavo  volume,  with  plates     (Now  Ready.)    tSJF3  See  RICORD. 
ALSO,  HUNTER'S  COMPLETE  WORKS,  with  Memoir,  Notes,  &c.  &c.    In  four  neat  octavo 
volumes,  with  plates. 

HUGHES   (H.    M.),  M.  D., 

Assistant  Physician  to  Guy's  Hospital,  &c. 

A  CLINICAL  INTRODUCTION   TO   THE    PRACTICE   OF  AUSCULTA- 
TION, and  other  Modes  of  Physical  Diagnosis,  in  Diseases  of  the  Lungs  and  Heart.    Second 
American  from  the  Second  and  Improved  London  Edition.  In  one  royal  12mo.  vol.  (Now  Ready.) 
It  has  been  carefully  revised  throughout.     Some  small  portions  have  been  erased ;  much  has 
been,  I  trust,  amended;  and  a  great  deal  of  new  matter  has  been  added;  so  that,  though  funda- 
mentally it  is  the  same  book,  it  is  in  many  respects  a  new  work. — Preface. 

HORNER  (WILLIAM  E.),  M.  D., 
Professor  of  Anatomy  in  the  University  of  Pennsylvania. 

SPECIAL   ANATOMY   AND    HISTOLOGY.     Eighth  edition.     Extensively 

revised  and  modified.    In  two  large  octavo  volumes,  of  more  than  one  thousand  pages,  hand- 
somely printed,  with  over  three  hundred  illustrations. 

This  work  has  enjoyed  a-thorough  and  laborious  revision  on  the  part  of  the  author,  with  the 
view  of  bringing  it  fully  up  to  the  existing  state  of  knowledge  on  the  subject  of  general  and  special 
anatomy.  To  adapt  it  more  perfectly  to  the  wants  of  the  student,  he  has  introduced  a  large  number 
of  additional  wood-engravings,  illustrative  of  the  objects  described,  while  the  publishers  have  en- 
deavored to  render  the  mechanical  execution  of  the  work  worthy  of  the  extended  reputation  which 
it  has  acquired.  The  demand  which  has  carried  it  to  an  EIGHTH  EDITION  is  a  sufficient  evi- 
dence of  the  value  of  the  work,  and  of  its  adaptation  to  the  wants  of  the  student  and  professional 
reader. 


HOBLYN  (RICHARD  D.),  A.  M  . 
A  DICTIONARY  OF  THE   TERMS  USED  IN  MEDICINE   AND   THE 

COLLATERAL   SCIENCES.     Second  and  Improved  American  Edition.     Revised,  with  nu- 
merous Additions,  from  the  second  London  edition,  by  ISAAC  HAYS,  M.  D.,  &c.    In  one  large 
royal  12mo.  volume,  of  over  four  hundred  pages,  double  columns.     (Nearly  Ready.} 
In  passing  this  work  a  second  time  through  the  press,  the  editor  has  subjected  it  to  a  very  tho- 
rough revision,  making  such  additions  as  the  progress  of  science  has  rendered  desirable,  and  sup- 
plying any  omissions  that  may  have  previously  existed.     As  a  concise  and  convenient  Dictionary 
of  Medical  Terms,  at  an.  exceedingly  low  price,  it  will  therefore  be  found  of  great  value  to  the  stu- 
dent and  practitioner. 

HOPE  (J.),   M.  D.,  F.  R.  S.,  &c. 
A  TREATISE  ON  THE    DISEASES    OF    THE    HEART   AND   GREAT 

VESSELS.     Edited  by  PENNOCK.     In  one  volume,  octavo,  with  plates,  572  pages. 
JONES  (C.  HANDFIELD),  F.  R.  S.,  &  EDWARD  H.  SIEVEKINQ,  M.D., 

Assistant  Physicians  and  Lecturers  in  St.  Mary's  Hospital,  London. 

A  MANUAL  OF  PATHOLOGICAL  ANATOMY.     With  400  engravings  on 

wood.  In  one  large  and  handsome  octavo  volume,  of  about  seven  hundred  pages.  (Now  Ready.) 
This  work  will  supply  a  want  which  has  been  felt  of  a  volume  which,  within  a  reasonable  size, 
should  contain  a  clear  and  connected  view  of  the  present  advanced  state  of  pathological  anatomy, 
embodying  the  numerous  investigations  and  discoveries  of  recent  observers,  who,  with  the  aid  of 
the  microscope,  have  so  greatly  enlarged  the  boundaries  of  pathological  science.  This  has  been 
the  aim  of  the  authors,  and  their  reputation  is  sufficient  guarantee  that  the  object  has  been  attained. 
The  publishers  have  omitted  nothing  that  is  requisite  to  the  full  appreciation  and  understanding  of 
the  subject,  and  the  very  numerous  illustrations  with  which  the  volume  abounds,  will,  it  is  hoped, 
fully  elucidate  the  details  and  descriptions. 

JONES  (T.  WHARTON),   F.  R.  S.,  &c. 
THE  PRINCIPLES  AND  PRACTICE  OF   OPHTHALMIC    MEDICINE 

AND  SURGERY.    Edited  by  ISAAC  HAYS,  M.  D.,  &c.     In  one  very  neat  volume,  large  royal 
12mo.,  of  529  pages,  with  four  plates,  plain  or  colored,  and  ninety-eight  wood-cuts. 


The  work  amply  sustains,  in  every  point  the  al- 
ready high  reputation  of  the  author  as  an  ophthalmic 
surgeon  as  well  as  a  physiologist  and  pathologist. 
The  book  ia  evidently  the  result  of  much  labor  and 
research,  and  has  been  written  with  the  greatest 
care  and  attention.  We  entertain  little  doubt  that 
this  book  will  become  what  its  author  hoped  it 


might  become,  a  manual  for  daily  reference  and 
consultation  by  the  student  and  the  general  practi- 
tioner. The  work  is  marked  by  that  correctness, 
clearness,  and  precision  of  style  which  distinguish 
all  the  productions  of  the  learned  author. — British 
and  Foreign  Medical  Review. 


18 


BLANCHARD   &   LEA'S   MEDICAL 


KIRKES  (WILLIAM   SENHOUSE),    M.  D., 

Demonstrator  of  Morbid  Anatomy  at  St.  Bartholomew's  Hospital,  &c.;  and 

JAMES   PAGET,   F.  R.  S., 

Lecturer  on  General  Anatomy  and  Physiology  in  St.  Bartholomew's  Hospital. 

A  MANUAL  OF  PHYSIOLOGY.  Second  American,  from  the  second  and 
improved  London  edition.  With  one  hundred  and  sixty-five  illustration?.  In  one  large  and 
handsome  royal  12mo.  volume,  pp.  550.  (Just  Issued.) 


In  the  present  edition,  the  Manual  of  Physiology 
has  been  brought  up  to  the  actual  condition  of  the 
science,  and  fully  sustains  the  reputation  which  it 
has  already  so  deservedly  attained.  We  consider 
the  work  of  MM.  Kirkes  and  Pnget  to  constitute  one 
of  the  very  best  handbooks  of  Physiology  we  possess 
— presenting  just  such  an  outline  of  the  science,  com- 
prising an  account  of  its  leading  facts  and  generally 
admitted  principles,  as  the  student  requires  during 
his  attendance  upon  a  course  of  lectures,  or  for  re- 
ference whilst  preparing  for  examination.  The  text 
is  fully  and  ably  illustrated  by  a  series  of  very  supe- 
rior wood-engravings,  by  which  a. comprehension  of 
some  of  the  more  intricate  of  the  subjects  treated  of 
is  greatly  facilitated. — Am.  Medical  Journal. 

We  need  only  say,  that,  without  entering  into  dis- 
cussions of  unsettled  questions,  it  contains  all  the 
recent  improvements  in  this  department  of  medical 
science.  For  the  student  beginning  this  study,  and 
the  practitioner  who  has  but  leisure  to  refresh  his 
memory,  this  book  is  invaluable,  as  it  contains  all 


that  it  is  important  to  know,  without  special  details, 
which  are  read  with  interest  only  by  those  who 
would  make  a  specialty,  or  desire  to  possess  a  criti- 
cal knowledge  of  the  subject. — Charleston  Medical 
Journal. 

One  of  the  best  treatises  that  can  be  put  into  the 
hands  of  the  student. — London  Medical  Gazette. 

The  general  favor  with  which  the  first  edition  of 
this  work  was  received,  and  its  adoption  as  a  favor- 
ite text-book  by  many  of  our  colleges,  will  insure  a 
large  circulation  to  this  improved  edition.  It  will 
fully  meet  the  wants  of  the  student.  —  Southern 
Med.  and  Surg.  Journal. 

Particularly  adapted  to  those  who  desire  to  pos- 
sess a  concise  digest  of  the  facts  of  Human  Physi- 
ology.— British  and  Foreign  Med.-Chirurg.  Review. 

We  conscientiously  recommend  it  as  an  admira- 
ble "Handbook  of  Physiology." — London  Journal 
of  Medicine. 


KNAPP  (F.),  PH.  D.,  &c. 

TECHNOLOGY ;  or,  Chemistry  applied  to  the  Arts  and  to  Manufactures.  Edited, 
with  numerous  Notes  and  Additions,  by  Dr.  EDMUND  RONALDS  and  Dr.  THOMAS  RICHARDSON. 
First  American  edition,  with  Notes  and  Additions,  by  Prof.  WALTER  R.  JOHNSON.  In  two  hand- 
some octavo  volumes,  printed  and  illustrated  in  the  highest  style  of  art,  with  about  five  hundred 
wood-engravings. 


PHYSIOLOGICAL 

(Preparing.) 


LEHMANN. 
CHEMISTRY.     Translated  by  GEORGE  E.  DAY,  M.  D. 


LEE  (ROBERT),    M.  D.,  F.  R.  S.,  &c. 

CLINICAL    MIDWIFERY;    comprising  the   Histories  of  Five  Hundred  and 
Forty-five  Cases  of  Difficult,  Preternatural,  and  Complicated  Labor,  with  Commentaries, 
the  second  London  edition.     In  one  royal  12mo.  volume,  extra  cloth,  of  238  pages. 


From 


LA    ROCHE   (R.),    M.  D.,  &c. 

PNEUMONIA  ;  its  Supposed  Connection,  Pathological  and  Etiological,  with  Au- 
tumnal Fevers,  including  an  Inquiry  into  the  Existence  and  Morbid  Agency  of  Malaria.  In  orre 
handsome  octavo  volume,  extra  cloth,  of  500  pages.  , 


A  more  simple,  clear,  and  forcible  exposition  of 
the  groundless  nature  and  dangerous  tendency  of 
certain  pathological  and  etiological  heresies,  has 
seldom  been  presented  to  our  notice.  —  N.  Y.  Journal 
of  Medicine  and  Collateral  Science,  March,  1854. 

This  work  should  be  carefully  studied  by  Southern 
physicians,  embodying  as  it  does  the  reflections  of 
an  original  thinker  and  close  observer  on  a  subject 
peculiarly  their  own.—  Virginia  Med.  and  Surgical 
Journal. 

The  author  had  prepared  us  to  expect  a  treatise 
from  him,  by  his  brief  papers  on  kindred  topics  in 


the  periodical  press,  and  yet  in  the  work  before  us 
he  has  exhibited  an  amount  of  industry  and  learning, 
research  and  ability,  beyond  what  we  are  accustomed 
to  discover  in  modern  medical  writers ;  while  his 
own  extensive  opportunities  for  observation  and 
experience  have  been  improved  by  the  most  laudable 
diligence,  and  display  a  familiarity  with,  the  whole 
subject  in  every  aspect,  which  commands  both  our 
respect  and  confidence.  As  a  corrective  of  prevalent 
and  mischievous  error,  sought  to  be  propagated  by 
novices  and  innovators,  we  could  wish  that  Dr.  La 
Roche's  book  could  be  widely  read.— N.  Y.  Medical 
Gazette. 


BY  THE  SAME  AUTHOR.      (In  Press.) 

YELLOW  FEVER,  considered   in  its  Historical,  Pathological,  and   Etiological 
Relations.     In  one  very  large  and  handsome  octavo  volume. 


LONGET   (F.  A.) 

TREATISE  ON  PHYSIOLOGY.  With  numerous  Illustrations.  Translated 
from  the  French  by  F.  G.  Smith,  M.  D.,  Professor  of  Institutes  of  Medicine  in  the  Pennsylvania 
Medical  College.  (Preparing.) 


AND   SCIENTIFIC   PUBLICATIONS.  19 

LAWRENCE  (W.),   F.  R.  S.,  &c. 
A  TREATISE    ON    DISEASES    OF    THE    EYE.     A    new  edition,   edited, 

with  numerous  additions,  and  243  illustrations,  by  ISAAC  HAYS,  M.  D.,  Surgeon  to  Wills  Hospi- 
tal, &c.     In  one  very  large  and  handsome  octavo  volume,  of  950  pages,  strongly  bound  in  leather 
with  raised  bands.     (Now  Ready.) 
This  work  is  thoroughly  revised  and  brought  up  to  1854. 

This  work  is  so  universally  recognized  as  the  standard  authority  on  the  subject,  that  the  pub- 
Kshers  in  presenting  this  new  edition  have  only  to  remark  that  in  its  preparation  the  editor  has 
carefully  revised  every  portion,  introducing  additions  and  illustrations  wherever  the  advance  of 
science  has  rendered  them  necessary  or  desirable.  In  this  manner  it  will  be  found  to  con- 
tain over  one  hundred  pages  more  than  the  last  edition,  while  the  list  of  wood-engravings 
has  been  increased  by  sixty-seven  figures,  besides  numerous  improved  illustrations  substituted 
for  such  as  were  deemed  imperfect  or  unsatisfactory.  The  various  important  contributions  to 
ophthalmological  science,  recently  made  by  Dalrymple,  Jacob,  Walton,  Wilde,  Cooper,  &c., 
both  in  the  form  of  separate  treatises  and  contributions  to  periodicals,  have  been  carefully 
examined  by  the  editor,  and,  combined  with  the  results  of  his  own  experience,  have  been 
freely  introduced  throughout  the  volume,  rendering  it  a  complete  and  thorough  exponent  of 
the  most  advanced  state  of  the  subject. 

In  a  future  number  we  shall  notice  more  at  length  '  octavo  pages—  has  enabled  both  author  and  editor  to 
this  admirable  treatise  — the  safest  guide  and  most  >  do  justice  to  all  the  details  of  this  subject,  and  con- 
comprehensive  work  of  reference,  which  is  within  |  dense  in  this  single  volume  the  present  state  of  our 
the  reach  of  all  classes  of  the  profession.— Stetho-  \  knowledge  of  the  whole  science  in  this  department, 
scope,  March,  1854.  whereby  its  pi-actieal  value  cannot  be  excelled.  We 

heartily  commend  it,  especially  as  a  hook  of  refe- 

This  standard  text-book  on  the  department  of  |  rence,  indispensable  in  every  medical  library.  The 
which  it  treats,  has  not  been  superseded,  by  any  or  j  additions  of  the  American  editor  very  greatly  en- 
all  of  the  numerous  publications  on  the  subject  !  nance  the  value  of  the  work,  exhibiting  the  learning 
heretofore  issued.  Nor  with  the  multiplied  improve-  j  and  experience  of  Dr.  Hays,  in  the  light  in  which  he 
ments  of  Dr.  Hays,  the  American  editor,  is  it  at  all  !  ought  to  be  held,  as  a  standard  authority  on  all  sub- 
likely  that  this  great  work  will  cease  to  merit  the  j  jects  appertaining  to  this  specialty,  to  which  he  has 
confidence  and  preference  of  students  or  practition-  rendered  so  many  valuable  contributions.— N.  Y. 
ers.  Its  ample  extent— nearly  one  thousand  large  |  Medical  Gazette. 

BY   THE   SAME   AUTHOR. 

A  TREATISE  ON  RUPTURES;  from  the  fifth  London  edition.    In  one  octavo 

volume,  sheep,  480  pages. 


LUDLOW    (J.    L.),    M.  D., 

Lecturer  on  Clinical  Medicine  at  the  Philadelphia  Almshouse,  &c. 

A  MANUAL  OF  EXAMINATIONS  upon  Anatomy  and  Physiology,  Surgery, 
Practice  of  Medicine,  Chemistry,  Obstetrics,  Materia  Medica,  Pharmacy,  and  Therapeutics. 
Designed  for  Students  of  Medicine  throughout  the  United  States.  A  new  edition,  revised  and 
extensively  improved.  In  one  large  royal  12mo.  volume,  with  several  hundred  illustrations. 
(Preparing.) 

LISTON  (ROBERT),   F.  R.S.,  &c. 
LECTURES  ON  THE  OPERATIONS  OF  SURGERY,  and  on  Diseases  and 

Accidents  requiring  Operations.    Edited,  with  numerous  Additions  and  Alterations,  by  T.  D. 
j  M.  D.     In  one  large  and  handsome  octavo  volume,  of  506  pages,  with  216  wood-cuts. 


LALLEMAND  (M.). 
THE    CAUSES,    SYMPTOMS,    AND    TREATMENT    OF    SPERMATOR- 

RHOEA.   Translated  and  edited  by  HENRY  J.  McDouGAL.    In  one  volume,  octavo,  320  pages. 
Second  American  edition.     (Now  Ready.) 

LARDNER  (DIONYSIUS),   D.  C.  L.,  &c. 
HANDBOOKS    OF    NATURAL    PHILOSOPHY    AND    ASTRONOMY. 

Revised,  with  numerous  Additions,  by  the  American  editor.  FIRST  COURSE,  containing  Mecha- 
nics, Hydrostatics,  Hydraulics,  Pneumatics,  Sound,  and  Optics.  In  one  large  royal  12mo. 
volume,  of  750  pages,  with  424  wood-cuts.  SECOND  COURSE,  containing  Heat,  Electricity,  Mag- 
netism, and  Galvanism,  one  volume,  large  royal  12mo.,  of  450  pages,  with  250  illustrations. 
THIRD  COURSE  (  now  ready),  containing  Meteorology  and  Astronomy,  in  one  large  volume,  royal 
12mo.  of  nearly  eight  hundred  pages,  with  thirty-seven  plates  and  two  hundred  wood-cuts.  The 
whole  complete  in  three  volumes,  of  about  two  thousand  large  pages,  with  over  one  thousand 
figures  on  steel  and  wood. 
The  various  sciences  treated  in  this  work  will  be  found  brought  thoroughly  up  to  the  latest  period. 


The  work  furnishes  a  very  clear  and  satisfactory 
account  of  our  knowledge  in  the  important  depart- 
ment of  science  of  which  it  treats.  Although  the 
medical  schools  of  this  country  do  not  include  the 


factory  manner  the  information   they  desire. — The 
Virginia  Med.  and  Surg.  Journal. 

The  present  treatise  is  a  most  complete  digest  of 


study  of  physics  in  their  course  of  instruction,  yet    all  that  has  been  developed  in  relation  to  the  great 
no  student  or  practitioner  should  be  ignorant  of  its     forces  of  nature,  Heat,  Magnetism,  and  Electricity. 


laws.  Besides  being  of  constant  application  in  prac- 
tice, such  knowledge  is  of  inestimable  utility  in  fa- 
cilitating the  study  of  other  branches  of  science.  To 
students,  then,  and  to  those  who,  h 
tered  upon  the  active  pursuits  of  b 
ous  to  sustain  and  improve  their  knowledge  of  the 
general  truths  of  natural  philosophy,  we  can  recom- 
mend this  work  as  supplying  in  a  clear  and  satis- 


o,  having  already  en- 
>f  business,  aredesir- 


Their  laws  are  elucidated  in  a  manner  both  pleasing 
and  familiar,  and  at  the  same  time  perfectly  intelli- 
gible to  the  student.  The  illustrations  are  suffi- 
ciently numerous  and  appropriate,  and  altogether 
we  can  cordially  recommend  the  work  as  well-de- 
serving the  notice  both  of  the  practising  physician 
and  the  student  of  medicine.— The  Med.  Examiner. 


20 


BLANCHARD    &   LEA'S    MEDICAL 


MEIGS  (CHARLES  D.),  M.  D., 
Professor  of  Obstetrics,  &c.  in  the  Jefferson  Medical  College,  Philadelphia. 

ON    THE    NATURE,    SIGNS,    AND    TREATMENT    OF    CHILDBED 

FEVER.     In  a  Series  of  Letters  addressed  to  the  Students  of  his  Class.     In  one  handsome 
octavo  volume,  of  three  hundred  and  sixty-five  pages.    (Now  Ready.) 

BY   THE   SAME    AUTHOR. 

WOMAN:  HER  DISEASES  AND  THEIR  REMEDIES.     A  Series  of  Lee- 

tures  to  his  Class.     Third  and  Improved  edition.     In  one  large  and  beautifully  printed  octavo 

volume.     (Just  Issued.     Revised  and  enlarged  to  1854.) 

The  gratifying  appreciation  of  his  labors,  as  evinced  by  the  exhaustion  of  two  large  impressions 
ef  this  work  within  a  few  years,  has  not  been  lost  upon  the  author,  who  has  endeavored  in  every 
way  fo  render  it  worthy  of  the  favor  with  which  it  has  been  received.  The  opportunity  thus 
afforded  for  a  second  revision  has  been  improved,  and  the  work  is  now  presented  as  in  every  way 
superior  to  its  predecessors,  additions  and  alterations  having  been  made  whenever  the  advance  of 
science  has  rendered  them  desirable.  The  typographical  execution  of  the  work  will  also  be  found 
to  have  undergone  a  similar  improvement  and  the  work  is  now  confidently  presented  as  in  every 
way  worthy  the  position  it  has  acquired  as  the  standard  American  text-book  on  the  Diseases  oit 
Females. 


It  contains  a  vast  amount  of  practical  knowledge, 
by  one  who  has  accurately  observed  and  retained 
the  experience  of  many  years,  and  who  tells  the  re- 
sult in  a  free,  familiar,  and  pleasant  manner. — Dub- 
lin Quarterly  Journal. 

There  is  an  off-hand  fervor,  a  glow,  and  a  warm- 
heartedness infecting  the  effort  of  Dr.  Meigs,  which 
is  entirely  captivating,  and  which  absolutely  hur- 
ries the  reader  through  from  beginning  to  end.  Be- 
sides, the  book  teems  with  solid  instruction,  and 
it  shows  the  very  highest  evidence  of  ability,  viz., 
the  clearness  with  which  the  information  is  pre- 
sented. We  know  of  no  better  test  of  one's  under- 
standing a  subject  than  the  evidence  of  the  power 
of  lucidly  explaining  it.  The  most  elementary,  as 
well  as  the  obscurest  subjects,  under  the  pencil  of 
Prof.  Meigs,  are  isolated  and  made  to  stand  out  in 
such  bold  relief,  as  to  produce  distinct  impressions 
upon  the  mind  and  memory  of  the  reader.  —  The 
Charleston  Med.  Journal. 


Professor  Meigs  has  enlarged  and  amended  this 
great  work,  for  such  it  unquestionably  is,  having 
passed  the  ordeal  of  criticism  at  home  and  abroad, 
but  been  improved  thereby  ;  for  in  this  new  edition 
the  author  has  introduced  real  improvements,  and 
increased  the  value  and  utility  of  the  book  ilfn- 
measurably.  It  presents  so  many  novel,  bright, 
and  sparkling  thoughts;  such  an  exuberance  of  new 
ideas  on  almost  every  page,  that  we  confess  our- 
selves to  have  become  enamored  with  the  book 
and  its  author  ;  and  cannot  withhold  our  congratu- 
lations from  our  Philadelphia  confreres,  that  such  a 
teacher  is  in  their  service.  We  regret  that  our 
limits  will  not  allow  of  a  more  extended  notice  of 
this  work,  but  must  content  ourselves  with  thus 
commending  it  as  worthy  of  diligent  perusal  by 
physicians  as  well  as  students,  who  are  seeking  to 
be  thoroughly  instructed  in  the  important  practical 
subjects  of  which  it  treats. — N.  Y.  Med.  Gazette. 


BY   THE   SAME   AUTHOR. 


OBSTETRICS :  THE  SCIENCE  AND   THE   ART.     Second  edition,  revised 

and  improved.     With  one  hundred  and  thirty-one  illustrations.     In  one  beautifully  printed  octavo 
volume,  of  seven  hundred  and  fifty-two  large  pages.     (Lately  Published.} 

The  rapid  demand  for  a  second  edition  of  this  work  is  a  sufficient  evidence  that  it  has  supplied 
a  desideratum  of  the  profession,  notwithstanding  the  numerous  treatises  on  the  same  subject  which 
have  appeared  within  the  last  few  years.  Adopting  a  system  of  his  own,  the  author  has  combined 
the  leading  principles  of  his  interesting  and  difficult  subject,  with  a  thorough  exposition  of  its  rules 
of  practice,  presenting  the  results  of  long  and  extensive  experience  and  of  familiar  acquaintance 
with  all  the  modern  writers  on  this  department  of  medicine.  As  an  American  Treatise  on  Mid- 
wifery, which  has  at  once  assumed  the  position  of  a  classic,  it  possesses  peculiar  claims  to  the  at- 
tention and  study  of  the  practitioner  and  student,  while  the  numerous  alterations  and  revisions 
which  it  has  undergone  in  the  present  edition  are  shown  by  the  great  enlargement  of  the  work, 
which  is  not  only  increased  as  to  the  size  of  the  page,  but  also  in  the  number.  Among  other  addi- 
tions may  be  mentioned 

A  NEW  AND  IMPORTANT  CHAPTER  ON  "CHILDBED  FEVER." 


BY  THE  SAME  AUTHOR.     (Now  Ready.) 

A  TREATISE  ON  ACUTE  AND  CHRONIC  DISEASES  OF  THE  NECK 

OF  THE  UTERUS.     With  numerous  plates,  drawn  and  colored  from  nature  in  the  highest 
style  of  art.    In  one  handsome  octavo  volume,  extra  cloth. 

The  object  of  the  author  in  this  work  has  been  to  present  in  a  small  compass  the  practical  results 
of  his  long  experience  in  this  important  and  distressing  class  of  diseases.  The  great  changes  intro- 
duced into  practice,  and  the  accessions  to  our  knowledge  on  the  subject,  within  the  last  few  years, 
resulting  from  the  use  of  the  metroscope,  brings  within  the  ordinary  practice  of  every  physician 
numerous  cases  which  were  formerly  regarded  as  incurable,  and  renders  of  great  value  a  work  like 
the  present  combining  practical  directions  for  diagnosis  and  treatment  with  an  ample  series  of  illus- 
trations, copied  accurately  from  colored  drawings  made  by  the  author,  after  nature.  No  such  accu- 
rate delineations  of  the  pathology  of  the  neck  of  the  uterus  have  heretofore  been  given,  requiring, 
as  they  do  the  rare  combination  of  physician  nnd  artist,  and  their  paramount  importance  to  lot; 
physician  in  whose  practice  such  cases  are  frequent,  is  too  evident  to  be  dwelt  upon,  while  in 
artistic  execution  they  are  far  in  advance  of  anything  of  the  kind  as  yet  produced  in  this  country. 


BY   THE    SAME   AUTHOR. 

OBSERVATIONS   ON    CERTAIN    OF    THE    DISEASES 

CHILDREN.    In  one  handsome  octavo  volume,  of  214  pages. 


OF    YOUNG 


AND    SCIENTIFIC    PUBLICATIONS. 


21 


MILLER  (JAMES),   F.  R.  S.  E., 

Professor  of  Surgery  in  the  University  of  Edinburgh,  &c. 

PRINCIPLES  OF  SURGERY.  Third  American,  from  the  second  and  revised 
Edinburgh  edition.  Revised,  with  Additions,  by  F.  W.  SARGENT,  M.  D.,  author  of  "  Minor  Sur- 
gery," &c.  In  one  large  and  very  beautiful  volume,  of  seven  hundred  and  fifty-two  pages,  with 
two  hundred  and  forty  exquisite  illustrations  on  wood. 

The  publishers  have  endeavored  to  render  the  present  edition  of  this  work,  in  every  point  of  me- 
chanical execution,  worthy  of  its  very  high  reputation,  and  they  confidently  present  it  te  the  pro- 
fession as  one  of  the  handsomest  volumes  as  yet  issued  in  this  country. 


This  edition  is  far  superior,  both  in  the  abundance 
and  quality  of  its  material,  to  any  of  the  preceding. 
We  hope  it  will  be  extensively  read,  and  the  sound 
principles  which  are  herein  taught  treasured  up  for 
future  application.  The  work  takes  rank  with 
Watson's  Practice  of  Physic;  it  certainly  does  not 
fall  behind  that  great  work  in  soundness  of  princi- 
ple or  depth  of  reasoning  and  research.  No  physi- 
cian who  values  his  reputation,  or  seeks  the  interests 
of  his  clients,  can  acquit  himself  before  his  God  and 
the  world  without  making  himself  familiar  with  the 
sound  and  philosophical  views  developed  in  the  fore- 
oing  book. — New  Orleans  Medical  and  Surgical 


guage.  This  opinion,  deliberately  formed  after  a 
careful  study  of  the  first  edition,  we  have  had  no 
cause  to  change  on  examining  the  second.  This 
edition  has  undergone  thorough  revision  by  the  au- 
thor; many  expressions  have  been  modified,  and  a 
mass  of  new  matter  introduced.  The  hook  is  got  up 
in  the  finest  style,  and  is  an  evidence  of  the  progress 
of  typography  in  our  country.— Charleston  Medical 
Journal  and  Review. 

We  recommend  it  to  both  student  and  practitioner, 
feeling  assured  that  as  it  now  comes  to  us,  it  pre- 
sents the  most  satisfactory  exposition  of  the  modern 
doctrines  of  the  principles  of  surgery  to  be  found  in 
any  volume  in  any  language.— N.  Y.  Journal  of 
Medicine, 


going  DOC 
Journal. 

Without  doubt  the  ablest  exposition  of  the  prin- 
ciples of  that  branch  of  the  healing  art  in  any  lan- 

BY  THE  SAME  AUTHOR.     (Now  Ready.) 

THE  PRACTICE  OF   SURGERY.     Third  American  from  the  second   Edin- 
burgh edition.    Edited,  with  Additions,  by  F.  W.  SARGENT,  M.  D  ,  one  of  the  Surgeons  to  Will's 
Hospital,  &c.    Illustrated  by  three  hundred  and  nineteen  engravings  on  wood.     In  one  large 
octavo  volume,  of  over  seven  hundred  pages. 
This  new  edition  will  be  found  greatly  improved  and  enlarged,  as  well  by  the  addition  of  much 

new  matter  as  by  the  introduction  of  a  large  and  complete  series  of  handsome  illustrations.    An 

equal  improvement  exists  in  the  mechanical  execution  of  the  work,  rendering  it  in  every  respect 

a  companion  volume  to  the  "Principles." 

No  encomium  of  ours  could  add  to  the  popularity 
of  Miller's  Surgery.  Its  reputation  in  this  country 
is  unsurpassed  by  that  of  any  other  work,  and,  when 
taken  in  connection  with  the  author's  Principles  of 
Surgery,  constitutes  a  whole,  without  reference  to 
which  no  conscientious  surgeon  would  be  willing 
to  practice  his  art.  The  additions,  by  Dr.  Sargent, 
have  materially  enhanced  the  value  of  the  work. — 
Southern  Medical  and  Surgical  Journal. 


It  is  seldom  that  two  volumes  have  ever  made  so 
profound  an  impression  in  so  short  a  time  as  the 
"Principles"  and  the  "Practice"  of  Surgery  by 
Mr.  Miller  —  or  so  richly  merited  the  reputation  they 
have  acquired.  The  author  is  an  eminently  sensi- 
ble, practical,  and  well-informed  man,  who  knows 
exactly  what  he  is  talking  about  and  exactly  how  to 
talk  it.—  Kentucky  Medical  Recorder. 

The  two  volumes  together  form  a  complete  exposfe 
of  the  present  state  of  Surgery,  and  they  ought  to  be 


on  the  shelves  of  every  surgeon. 
porter. 


N.  J.  Med.  Re- 


By the  almost  unanimous  voice  of  the  profession, 
his  works,  both  on  the  principles  and  practice  of 
surgery  have  been  assigned  the  highest  rank.  If  we 
were  limited  to  but  one  work  on  surgery,  that  one 


should  be  Miller's,  as  we  re 
others. — St.  Louis  Med.  and 


'ard  it  superior  to  aW 
urg.  Journal. 


The  author  distinguished  alike  as  a  practitioner 
and  writer,  has  in  this  and  his  "  Principles,"  pre- 
sented to  the  profession  one  of  the  most  complete  and 
reliable  systems  of  Surgery  extant.  His  style  of 
writing  is  original,  impressive,  and  engaging,  ener- 
getic, concise,  and  lucid.  Few  have  the  faculty  of 
condensing  so  much  in  small  space,  and  at  the  same 
time  so  persistently  holding  the  attention;  indeed, 
he  appears  to  make  the  very  process  oY  condensation 
a  means  of  eliminating  attractions.  Whether  as  a 
text-book  for  students  or  a  book  of  reference  for 
practitioners,  it  cannot  be  too  strongly  recommend- 
ed.— Southern  Journal  of  the  Medical  and  Physical 
Sciences. 


MALGAIGNE  (J.  F.). 

OPERATIVE  SURGERY,  based  on  Normal  and  Pathological  Anatomy.     Trans- 
lated from  the  French,  by  FREDERICK  BRITTAN,  A.  B.,  M.  D.    With  numerous  illustrations  on 
wood.    In  one  handsome  octavo  volume,  of  nearly  six  hundred  pages. 
We  have  long  been  accustomed  to  refer  to  it  as  one  I      To  express  in  a  few  words  our  opinion  of  Mal- 

of  the  most  valuable  text-books  in  our  library.—    gaigne's  work,  we  unhesitatingly  pronounce  it  the 


Buffalo  Med.  and  Surg.  Journal. 

Certainly  one  of  the  best  books  published  on  ope- 
rative surgery.— Edinburgh  Medical  Journal. 


very  best  guide  in  surgical  operations  that  has  come 
before  the  profession  in  any  language. — Charleston 
Med.  and  Surg.  Journal. 


MOHR  (FRANCIS),  PH.  D.,  AND  REDWOOD  (THEOPH  I  LUS). 

PRACTICAL  PHARMACY.  Comprising  the  Arrangements,  Apparatus,  and 
Manipulations  of  the  Pharmaceutical  Shop  and  Laboratory.  Edited,  with  extensive  Additions, 
by  Prof.  WILLIAM  PROCTER,  of  the  Philadelphia  College  of  Pharmacy.  In  one  handsomely 
printed  octavo  volume,  of  570  pages,  with  over  500  engravings  on  wood. 

sary  thereto. 


It  is  a  book,  however,  which  will  be  in  the  hands 
of  almost  every  one  who  is  much  interested  in  phar- 
maceutical operations,  as  we  know  of  no  other  pub- 
lication so  well  calculated  to  fill  a  void  long  felt.— 
Medical  Examiner. 

The  book  is  strictly  practical,  and  describes  only 
manipulations  or  methods  of  performing  the  nume- 
rous processes  the  pharmaceutist  has  to  go  through, 
ih  the  preparation  and  manufacture  of  medicines, 
together  with  all  the  apparatus  and  fixtures  neces-  I 


On  these  matters,  this  work  is  very 
full  and  complete,  and  details,  in  a  style  uncom- 
monly clear  and  lucid,  not  only  the  more  compli- 
cated and  difficult  processes,  but  those  not  less  im- 
portant ones,  the  most  simple  and  common. — Buffalo 
Medical  Journal. 

The  country  practitioner  who  is  obliged  to  dis- 
pense his  own  medicines,  Avill  find  it  a  most  valuable 
assistant. — Monthly  Journal  and  Retrospect. 


BLANCHARD    &    LEA'S    MEDICAL 


MACLISE    (JOSEPH),    SURGEON. 

SURGICAL   ANATOMY.     Forming  one  volume,   very  large  imperial  quarto. 

Con- 

with  copious 
the 
cheapest  and  best  executed  Surgicaf  works  as  yet  issued  in  this  country. 


jixurJ-^xxjj    xxii  ZY  J_  v_/ iu  J. .       jj  u      11115    <Jue    vuiuiiie,     veij    icugc    mi 
With  sixty-eight  large  and  splendid  Plates,  drawn  in  the  best  style  and  beautifully  colored.    C 
tain  ing  one  hundred  and  ninety  Figures,  many  of  them  the  size  of  life.     Together  with  copi' 
and  explanatory  letter-press.     Strongly  and  handsomely  bound  in  extra  cloth,  being  one  of 


Copies  can  be  sent  by  mail,  in  five  parts,  done  up  in  stout  covers. 

This  great  work  being  now  concluded,  the  publishers  confidently  present  it  to  the  attention  of  the 
profession  as  worthy  in  every  respect  of  their  approbation  and  patronage.  No  complete  work  of 
the  kind  has  yet  been  published  in  the  English  language,  and  it  therefore  will  supply  a  want  long 
felt  in  this  country  of  an  accurate  and  comprehensive  Atlas  of  Surgical  Anatomy  to  which  the 
student  and  practitioner  can  at  all  times  refer,  to  ascertain  the  exact  relative  position  of  the  various 
portions  of  the  human  frame  towards  each  other  and  to  the  surface,  as  well  as  their  abnormal  de- 
viations. The  importance  of  such  a  work  to  the  student  in  the  absence  of  anatomical  material,  and 
to  the  practitioner  when  about  attempting  an  operation,  is  evident,  while  the  price  of  the  book,  not- 
withstanding the  large  size,  beauty,  and  finish  of  the  very  numerous  illustrations,  is  so  low  as  to 
place  it  within  the  reach  of  every  member  of  the  profession.  The  publishers  therefore  confidently 
anticipate  a  very  extended  circulation  for  this  magnificent  work. 


One  of  the  greatest  artistic  triumphs  of  the  age 
in  Surgical  Anatomy.— British,  American  Medical 
Journal. 

Too  much  cannot  be  said  in  its  praise;  indeed, 
we  have  not  language  to  do  it  justice. — Ohio  Medi- 
cal and  Surgical  Journal. 

The  most  admirable  surgical  atlas  we  have  seen. 
To  the  practitioner  deprived  of  demonstrative  dis- 
sections upon  the  human  subject,  it  is  an  invaluable 
companion.— -.ZV.  J.  Medical  Reporter. 

The  most  accurately  engraved  and  beautifully 
colored  plates  we  have  ever  seen  in  an  American 
book — one  of  the  best  and  cheapest  surgical  works 
ever  published. — Buffalo  Medical  Journal. 

It  is  very  rare  that  so  elegantly  printed,  so  well 
illustrated,  and  so  useful  a  work,  is  offered  at  so 
moderate  a  price.— Charleston  Medical  Journal. 

Its  plates  can  boast  a  superiority  which  places 
them  almost  beyond  the  reach  of  competition. — Medi- 
cal Examiner. 

Every  practitioner,  we  think,  should  have  a  work 
of  this  kind  within  Teach.*— Southern  Medical  and 
Surgical  Journal. 

No  such  lithographic  illustrations  of  surgical  re- 
gions have  hitherto,  we  think,  been  given. — Boston 
Medical  and  Surgical  Journal. 

As  a  surgical  anatomist,  Mr.  Maclise  has  proba- 
bly no  superior. — British  and  Foreign  Medico-Chi- 
rurgical  Review. 

Of  great  value  to  the  student  engaged  in  dissect- 
ing, and  to  the  surgeon  at  a  distance  from  the  means 


of  keeping  up  his  anatomical  knowledge. — Medical 
Times. 

The  mechanical  execution  cannot  be  excelled. — 
Transylvania  Medical  Journal. 

A  work  which  has  no  parallel  in  point  of  accu- 
racy and  cheapness  in  the  English  language. — N.  Y. 
Journal  of  Medicine. 

To  all  engaged  in  the  study  or  practice  of  their 
profession,  such  a  work  is  almost  indispensable. — 
Dublin  Quarterly  Medical  Journal. 

No  practitioner  whose  means  will  admit  should 
fail  to  possess  it. — Ranking's  Abstract. 

Country  practitioners  will  find  these  plates  of  im- 
mense value. — N.  Y.  Medical  Gazette. 

We  are  extremely  gratified  to  announce  to  the 
profession  the  completion  of  this  truly  magnificent 
work,  which,  as  a  whole,  certainly  stands  unri- 
valled, both  for  accuracy  of  drawing,  beauty  of 
coloring,  and  all  the  requisite  explanations  of  the 
subject  in  hand. — The  New  Orleans  Medical  and 
Surgical  Journal. 

This  is  by  far  the  ablest  work  on  Surgical  Ana- 
tomy that  has  come  under  our  observation.  We 
know  of  no  other  work  that  would  justify  a  stu- 
dent, in  any  degree,  for  neglect  of  actual  dissec- 
tion. Jn  those  sudden  emergencies  that  so  often 
arise,  and  which  require  the  instantaneous  command 
of  minute  anatomical  knowledge,  a  work  of  this  kind 
keeps  the  details  of  the  dissecting-room  perpetually 
fresh  in  the  memory. — The  Western  Journal  of  Medi- 
cine and  Surgery. 

The  very  low  price  at  which  this  work  is  furnished,  and  the  beauty  of  its  execution, 
require  an  extended  sale  to  compensate  the  publishers  for  the  heavy  expenses  incurred. 


MULLER  (PROFESSOR  J.),   M.  D. 

PRINCIPLES  OF  PHYSICS  AND  METEOROLOGY.  Edited,  with  Addi- 
tions, by  R.  EGLESFELD  GRIFFITH,  M.  D.  In  one  large  and  handsome  octavo  volume,  extra 
cloth,  with  550  wood-cuts,  and  two  colored  plates. 

The  Physics  of  Mflller  is  a  work  superb,  complete.  I  tion  to  the  scientific  records  of  this  country  may  be 
unique:  the  greatest  want  known  to  English  Science  [  duly  estimated  by  the  fact  that  the  cost  of  the  origi- 
could  not  have  been  better  supplied.  The  work  is  I  nal  drawings  and  engravings  alone  has  exceeded  tiie 
of  surpassing  interest.  The  value  of  this  contribu-  |  sum  of  .£'2,000. — Lancet. 


MAYNE  (JOHN),  M.  D.,  M.  R.  C.  S. 
A  DISPENSATORY  AND  THERAPEUTICAL  REMEMBRANCER.   Com- 

S  rising  the  entire  lists  of  Materia  Medica,  with  every  Practical  Formula  contained  in  the  three 
riti^h  Pharmacopoeias.    With  relative  Tables  subjoined,  illustrating,  by  upwards  of  six  hundred 
and  sixty  examples,   the  Extemporaneous  Forms  and  Combinations  suitable  for  the  different 
Medicines.    Edited,  with  the  addition  of  the  Formulae  of  the  United  States  Pharmacopoeia,  by 
R.  EGLESFELD  GRIFFITH,  M.  D.    In  one  12mo.  volume,  extra  cloth,  of  over  300  large  pages. 


MATTEUCCI  (CARLO). 
LECTURES  ON  THE  PHYSICAL  PHENOMENA  OF  LIVING  BEINGS. 

Edited  by  J.  PEREIRA,  M.  D.    In  one  neat  royal  12mo.  volume,  extra  cloth,  with  cuts,  388  pages- 


AND  SCIENTIFIC    PUBLICATIONS.  23 

NEILL  (JOHN),   M.  D., 

Surgeon  to  the  Pennsylvania  Hospital,  &c.;  and 
FRANCIS  GURNEY  SMITH,   M.  D., 

Professor  of  Institutes  of  Medicine  in  the  Pennsylvania  Medical  College. 

AN  ANALYTICAL  COMPENDIUM  OF  THE  VARIOUS  BRANCHES 

OF  MEDICAL  SCIENCE  ;  for  the  Use  and  Examination  of  Students.  Second  edition,  revised 
and  improved.  In  one  very  large  and  handsomely  printed  royal  12mo.  volume,  of  over  one 
thousand  pages,  with  three  hundred  and  fifty  illustrations  on  wood.  Strongly  bound  in  leather, 
with  raised  bands. 

The  speedy  sale  of  a  large  impression  of  this  work  has  afforded  to  the  authors  gratifying  evidence 
m'  the  correctness  of  the  views  which  actuated  them  in  its  preparation.  In  meeting  the  demand 
for  a  second  edition,  they  have  therefore  been  desirous  to  render  it  more  worthy  of  the  favor  with 
which  it  has  been  received.  To  accomplish  this,  they  have  spared  neither  time  nor  labor  in  embo- 
dying in  it  such  discoveries  and  improvements  as  have  been  made  since  its  first  appearance,  and 
such  alterations  as  have  been  suggested  by  its  practical  use  in  the  class  and  examination-room. 
Considerable  modifications  have  thus  been  introduced  throughout  all  the  departments  treated  of  in 
the  volume,  but  more  especially  in  the  portion  devoted  to  the  "Practice  of  Medicine,"  which  has 
been  entirely  rearranged  and  rewritten.  The  authors  therefore  again  submit  their  work  to  the 
profession,  with  the  hope  that  their  efforts  may  tend,  however  humbly,  to  advance  the  great  cause 
of  medical  education. 

Notwithstanding  the  enlarged  size  and  improved  execution  of  this  work,  the  price  has  not  been 
increased,' and  it  is  confidently  presented  as  one  of  the  cheapest  volumes  now  before  the  profession. 


In  the  rapid  course  of  lectures,  where  work  for 
the  students  is  heavy,  and  review  necessary  for  an 
examination,  a  compend  is  not  only  valuable,  but 
it  is  almost  a  sine  qua  non.  The  one  before  us  is, 
in  most  of  the  divisions,  the  most  unexceptionable 
of  all  books  of  the  kind  that  we  know  of.  The 
newest  and  soundest  doctrines  and  the  latest  im- 
provements and  discoveries  are  explicitly,  though 
concisely,  laid  before  the  student.  Of  course  it  is 
useless  for  us  to  recommend  it  to  all  last  coui'se 
students,  but  there  is  a  class  to  whom  we  very 
sincerely  commend  this  cheap  book  as  worth  its 
weight  in  silver  — that  class  is  the  graduates  in 
medicine  of  more  than  ten  years'  standing,  who 
have  not  studied  medicine  since.  They  will  perhaps 
find  out  from  it  that  the  science  is  not  exactly  now 
•what  it  was  when  they  left  it  off.— The  Stethoscope 


Having  made  free  use  of  this  volume  in  our  ex- 
aminations of  pupils,  we  can  speak  from  experi- 
ence in  recommending  it  as  an  admirable  compend 
for  students,  and  as  especially  useful  to  preceptors 
who  examine  their  pupils.  It  will  save  the  teacher 
much  labor  by  enabling  him  readily  to  recall  all  of 
the  points  upon  which  his  pupils  should  be  ex- 
amined. A  work  of  this  sort  should  be  in  the  hands 
of  every  one  who  takes  pupils  into  his  office  with  a 
view  of  examining  them;  and  this  is  unquestionably 
the  best  of  its  class.  Let  every  practitioner  who  has 
rovide  himself  with  it,  and  he  will  find  the 
refreshing  his  knowledge  so  much  facilitated 
that  he  will  be  able  to  do  justice  to  his  pupils  at  very 
little  cost  of  time  or  trouble  to  himself  .—Transyl  - 
vania  Med.  Journal. 


pupils  pr 
labor  of  r 


NELIGAN  (J.    MOORE),  M.  D.,  M.  R.  I.  A.,  &c. 
A   PRACTICAL   TREATISE    ON   DISEASES    OF   THE    SKIN.     In  one 

neat  royal  12mo.  volume,  of  334  pages. 

OWEN  (PROF.    R.), 

Author  of"  Lectures  on  Comparative  Anatomy,"  "  Archetype  of  the  Skeleton,"  &c. 

ON  THE  DIFFERENT  FORMS   OF  THE  SKELETON,  AND  OF  THE 

TEETH.     One  vol.  royal  12mo.,  with  numerous  illustrations.    (Now  Ready.) 
The  name  of  the  distinguished  author  is  a  sufficient  guarantee  that  this  little  volume  will  prove 
a  satisfactory  manual  and  guide  to  all  students  of  Comparative  Anatomy  and  Osteology.     The  im- 
portance of  this  subject  in  geological  investigations  will  also  render  this  work  a   most  valuable 
assistant  to  those  interested  in  that  science. 


PHILLIPS  (BENJAMIN),   F.  R.  S.,  &c. 

SCROFULA;    its  Nature,  its  Prevalence,  its  Causes,  and  the  Principles  of  its 
Treatment.    In  one  volume,  octavo,  with  a  plate. 


PANCOAST  (J.),  M.  D., 
Professor  of  Anatomy  in  the  Jefferson  Medical  College,  Philadelphia,  &c. 

OPERATIVE  SURGERY;  or,  A  Description  and  Demonstration  of  the  various 
Processes  of  the  Art ;  including  all  the  New  Operations,  and  exhibiting  the  State  of  Surgical 
Science  in  its  present  advanced  condition.  Complete  in  one  royal  4to.  volume,  of  380  pages  of 
letter-press  description  and  eighty  large  4to.  plates,  comprising  486  illustrations.  Second  edition, 
improved. 

Bianchard  &  Lea  having  become  the  publishers  of  this  important  book,  have  much  pleasure  in 
oflering  it  to  the  profession. 


This  excellent  work  is  constructed  on  the  model 
of  the  French  Surgical  Works  by  Velpeau  and  Mal- 
gaigne;  and,  so  far  as  the  English  language  is  con- 


cerned, we  are  proud  as  an  American  to  say  that, 
OF  ITS  KIND  IT  HAS  NO  SUPERIOR.— N.  Y.  Journal  of 
Medicine. 


PARKER   (LANGSTON), 

Surgeon  to  the  Queen's  Hospital,  Birmingham. 

THE  MODERN  TREATMENT  OF  SYPHILITIC  DISEASES,  BOTH  PRI- 
MARY AND  SECONDARY;  comprising  the  Treatment  of  Constitutional  and  Confirmed  Syphi- 
lis, by  a  safe  and  successful  method.  With  numerous  Cases,  FormulEe,  and  Clinical  Observa- 
tions. From  the  Third  and  entirely  rewritten  London  edition.  In  one  neat  octavo  volume. 
(Now  Ready.) 


24 


BLANCHARD   &   LEA'S   MEDICAL 


(Now  Complete.) 

PEREIRA  (JONATHAN),  M.  D.,  F.  R.  S.,  AND  L.  S. 
THE    ELEMENTS    OF    MATERIA    MEDICA    AND    THERAPEUTICS. 

Third  American  edition,  enlarged  and  improved  by  the  author;  including  Notices  of  most  of  the 
Medicinal  Substances  in  use  in  the  civilized  world,  and  forming  an  Encyclopaedia  of  Materia 
Medica.  Edited,  with  Additions,  by  JOSEPH  CARSON,  M.  D.,  Professor  of  Materia  Medica  and 
Pharmacy  in  the  University  of  Pennsylvania.  In  two  very  large  octavo  volumes  of  2100  page*, 
on  small  type,  with  over  four  hundred  and  fifty  illustrations. 
VOLUME  I. — Lately  issued,  containing  the  Inorganic  Materia  Medica,  over  800  pages,  with  145 

illustrations. 

VOLUME  II. — Now  ready,  embraces  the  Organic  Materia  Medica,  and  forms  a  very  large  octavo 
volume  of  1250  pages,  with  two  plates  and  three  hundred  handsome  wood-cuts. 
The  present  edition  of  this  valuable  and  standard  work  will  enhance  in  every  respect  its  well- 
deserved  reputation.  The  care  bestowed  upon  its  revision  by  the  author  may  be  estimated  by  the 
fact  that  its  size  has  been  increased  by  about  five  hundred  pages.  These  additions  have  extended 
to  every  portion  of  the  work,  and  embrace  not  only  the  materials  afforded  by  the  recent  editions  of 
the  pharmacopoeias,  but  also  all  the  important  information  accessible  to  the  care  and  industry  of 
the  author  in  treatises,  essays,  memoirs,  monographs,  and  from  correspondents  in  various  parts  of 
the  globe.  In  this  manner  the  work  comprises  the  most  recent  and  reliable  information  respecting 
all  the  articles  of  the  Materia  Medica,  their  natural  and  commercial  history,  chemical  and  thera- 
peutical properties,  preparation,  uses,  doses,  and  modes  of  administration,  brought  up  to  the  present 
time,  with  a  completeness  not  to  be  met  with  elsewhere.  A  considerable  portion  of  the  work 
which  preceded  the  remainder  in  London,  has  also  enjoyed  the  advantage  of  a  further  revision  by 
the  author  expressly  for  this  country,  and  in  addition  to  this  the  editor,  Professor  Carson,  has  made 
whatever  additions  appeared  desirable  to  adapt  it  thoroughly  to  the  U.  S.  Pharmacopoeia,  and  to 
the  wants  of  the  American  profession.  An  equal  improvement  will  likewise  be  observable  in  every 
department  of  its  mechanical  execution.  It  is  printed  from  new  type,  on  good  white  paper,  with  a 
greatly  extended  and  improved  series  of  illustrations. 

Gentlemen  who  have  the  first  volume  are  recommended  to  complete  their  copies  without  delay. 
The  first  volume  will  no  longer  be  sold  separate. 
When  we  remember  that  Philology,  Natural  His-  I  Medica,  although  completed  under  the  supervision  of 


tory,  Botany,  Chemistry,  Physics,  and  the  Micro- 
scope, are  all  brought  forward  to  elucidate  the  sub- 
ject, one  cannot  fail  to  see  that  the  reader  has  here 
a  work  worthy  of  the  name  of  an  encyclopedia  of 
Materia  Medica.  Our  own  opinion  of  its  merits  is 
that  of  its  editors,  and  also  that  of  the  whole  profes- 
sion, both  of  this  and  foreign  countries— namely, 
"  that  in  copiousness  of  details,  in  extent,  variety, 
and  accuracy  of  information,  and  in  lucid  explana- 
tion of  difficult  and  recondite  subjects,  it  surpasses 
all  other  works  on  Materia  Medica  hitherto  pub- 
lished." We  cannot  close  this  notice  without  allud- 
ing to  the  special  additions  of  the  American  editor, 
which  pertain  to  the  prominent  vegetable  produc- 
tions of  this  country,  and  to  the  directions  of  the 
United  States  Pharmacopoeia,  in  connection  with  all 
the  articles  contained  in  the  volume  which  are  re- 
ferred to  by  it.  The  illustrations  have  been  increased, 
and  this  edition  by  Dr.  Carson  cannot  well  be  re- 
garded in  any  other  light  than  that  of  a  treasure 
which  should  be  found  in  the  library  of  every  physi- 
cian.— New  York  Journal  of  Medical  and  Collateral 
Science,  March,  1854. 

The  third  edition  of  his  "  Elements  of  Materia 


others,  is  by  far  the  most  elaborate  treatise  in  the 
English  language,  and  will,  while  medical  literature 
is  cherished,  continue  a  monument  alike  honorable 
to  his  genius,  as  to  his  learning  and  industry. — 
American  Journal  of  Pharmacy,  March,  1854. 

The  work,  in  its  present  shape,  and  so  far  as  can 
be  judged  from  the  portion  before  the  public,  forms 
the  most  comprehensive  and  complete  treatise  on 
materia  medica  extant  in  the  English  language. — 
Dr.  Pereira  has  been  at  great  pains  to  introduce 
into  his  work,  not  only  all  the  information  on  th-a 
natural,  chemical,  and  commercial  history  of  medi- 
cines, which  might  be  serviceable  to  the  -r 


and  surgeon,  but  whatever  might  enable  his  read- 
ers to  understand  thoroughly  the  mode  of  prepar- 
ing and  manufacturing  various  articles  employed 
either  for  preparing  medicines,  or  for  certain  pur- 
poses in  the  arts  connected  with  materia  medica 
and  the  practice  of  medicine.  The  accounts  of  the 
physiological  and  therapeutic  effects  of  remedies  awj 
given  with  great  clearness  and  accuracy,  and  in  a 
manner  calculated  to  interest  as  well  as  instruct 
the  reader. — The  Edinburgh  Medical  and  Surgical 
Journal. 


PEASELEE  (E.  R.),   M.  D., 

Professor  of  Anatomy  and  Physiology  in  Dartmouth  College,  &c. 

HUMAN  HISTOLOGY,  in  its  applications  to  Physiology  and  General  Pathology; 

designed  as  a  Text-Book  for  Medical  Students.    With  numerous  illustrations.     In  one  handsome 

royal  12mo.  volume.     (Preparing.') 

The  subject  of  this  work  is  one,  the  growing  importance  of  which,  as  the  basis  of  Anatomy  and 
Physiology,  demands  for  it  a  separate  volume.  The  book  will  therefore  supply  an  acknowledged 
deficiency  in  medical  text-books,  while  the  name  of  the  author,  and  his  experience  as  a  teacher  for 
the  last  thirteen  years,  is  a  guarantee  that  it  will  be  thoroughly  adapted  to  the  use  of  the  student. 

PIRRIE  (WILLIAM),  F.  R.  S.  E., 

Professor  of  Surgery  in  the  University  of  Aberdeen. 

THE    PRINCIPLES   AND  PRACTICE   OF   SURGERY.     Edited  by  JOHN 

NEILL,  M.  D.,  Demonstrator  of  Anatomy  in  the  University  of  Pennsylvania,  Surgeon  to  the 
Pennsylvania  Hospital,  &c.  In  one  very  handsome  octavo  volume,  of  ISO  pages,  with  316  illus- 
trations. (Just  Issued.) 


We  know  of  no  other  surgical  work  of  a  reason- 
able size,  wherein  there  is  so  much  theory  and  prac- 
tice, or  where  subjects  are  more  soundly  or  clearly 
taught. — The  Stethoscope. 

There  is  scarcely  a  disease  of  the  bone  or  soft 
parts,  fracture,  or  dislocation,  that  is  not  illustrated 
by  accurate  wood-engravings.  Then,  again,  every 
instrument  employed  by  the  surgeon  is  thus  repre- 
sented. These  engravings  are  not  only  correct,  but 
really  beautiful,  snowing  the  astonishing  degree  of 
perfection  to  which  the  art  of  wood-engraving  has 


arrived.  Prof.  Pirrie,  in  the  work  before  us,  has 
elaborately  discussed  the  principles  of  surgery,  and 
a  safe  and  effectual  practice  predicated  upon  them. 
Perhaps  no  work  upon  this  subject  heretofore  issued 
is  BO  full  upon  the  science  of  the  art  of  surgery. — 
Nashville  Journal  of  Medicine  and  Surgery. 

One  of  the  best  treatises  on  surgery  in  the  English 
language. — Canada  Med.  Journal. 

Our  impression  is,  that,  as  a  manual  for  students. 
Pirrie's  is  the  best  work  extant.— Western  Med.  and 
Surg.  Journal. 


AND    SCIENTIFIC    PUBLICATIONS. 


RAMSBOTHAM  (FRANCIS  H.),  M.D. 
THE  PRINCIPLES  AND  PRACTICE  OF  OBSTETRIC  MEDICINE  AND 

SURGERY",  in  reference  to  the  Process  of  Parturition.    Sixth  American,  from  the  last  London 

edition.    Illustrated  with  one  hundred  and  forty-eight  Figures,  on  fifty-five  Lithographic  Plates. 

In  one  large  and  handsomely  printed  volume,  imperial  octavo,  with  520  pages. 

In  this  edition,  the  plates  have  all  been  redrawn,  and  the  text  carefully  read  and  corrected.     It 
is  therefore  presented  as  in  every  way  worthy  the  favor  with  which  it  has  so  long  been  received. 
From  Prof.  Hodge,  of  the  University  of  Pa. 

To  the  American  public,  it  is  most  valuable,  from  its  intrinsic  undoubted  excellence,  and  as  being 
the  best  authorized  exponent  of  British  Midwifery.  Its  circulation  will,  I  trust,  be  extensive  throughout 
our  country. 


We  recommend  the  student  who  desires  to  mas- 
ter this  difficult  subject  with  the  least  possible 
trouble,  to  possess  himself  at  once  of  a  copy  of  this 
work. — American  Journal  of  the  Med.  Sciences. 

It  stands  at  the  head  of  the  long  list  of  excellent 
obstetric  works  published  in  the  last  few  years  in 
Great  Britain,  Ireland,  and  the  Continent  of  Eu- 
rope. We  consider  this  book  indispensable  to  the 
library  of  every  physician  engaged  in  the  practice 
of  midwifery.— Southern  Med.  and  Surg.  Journal. 


When  the  whole  profession  is  thus  unanimous 
in  placing  such  a  work  in  th«  very  first  rank  as 
regards  the  extent  and  correctness  of  all  the  details 
of  the  theory  and  practice  of  so  important  a  branch 
of  learning,  our  commendation  or  condemnation 
would  be  of  little  consequence;  but  regarding  it 
as  the  most  useful  of  all  works  of  the  kind,  we 
think  it  but  an  act  of  justice  to  urge  its  claims 
upon  the  profession. — N,  O.  Med.  Journal. 


RICORD  (P.),   M.  D., 
Surgeon  to  the  Hopital  du  Midi,  Paris,  &c. 

ILLUSTRATIONS  OF  SYPHILITIC  DISEASE.  Translated  from  the  French, 

by  THOMAS  F.  BETTON,  M.  D.  With  the  addition  of  a  History  of  Syphilis,  and  a  complete  Bib- 
liography and  Formulary  of  Remedies,  collated  and  arranged,  by  PAUL  B.  GODDARD,  M.  D.  "With 
fifty  large  quarto  plates,  comprising  one  hundred  and  seventeen  beautifully  colored  illustrations. 
In  one  large  and  handsome  quarto  volume. 

Blanchard  &  Lea  having  purchased  the  remainder  of  this  valuable  work,  which  was  originally 
sold  as  a  subscription  book,  are  now  prepared  to  offer  it  to  the  profession.  It  is  universally  known 
as  one  of  the  handsomest  volumes  as  yet  presented  in  this  country,  and  as  containing  the  only  ex- 
tended and  thorough  series  of  illustrations  on  the  subject. 

BY  THE  SAME  AUTHOR.      (Now  Ready.) 

A  TREATISE  ON  THE  VENEREAL  DISEASE.     By  JOHN  HUNTER,  F.  R.  S. 

With  copious  Additions,  by  PH.  RICORD,  M.  D.  Edited,  with  Notes,  by  FREEMAN  J.  BUMSTEAD, 
M.  D.  In  one  handsome  octavo  volume,  with  plates. 

From  the  Translator's  Preface. 

"  M.  Ricord's  annotations  to  Hunter's  Treatise  on  the  Venereal  Disease  were  first  published  at 
Paris,  in  1840,  in  connection  with  Dr.  G.  Richelot's  translation  of  the  work,  including  the  contri- 
butions of  Sir  Everard  Home  and  Mr.  Babington.  In  a  second  edition,  which  has  recently  ap- 
peared, M.  Ricord  has  thoroughly  revised  his  part  of  the  work,  bringing  it  up  to  the  knowledge  of 
the  present  day,  and  so  materially  increasing  it  that  it  now  constitutes  full  one-third  of  the  volume. 

"  This  publication  has  been  received  with  great  favor  by  the  French,  both  because  it  has  placed 
within  their  reach  an  important  work  of  Hunter,  and  also  because  it  is  the  only  recent  practical 
work  which  M.  Ricord  has  published,  no  edition  of  his  Traite  des  Maladies  Veneriennes  having 
appeared  for  the  last  fifteen  years." 


Every  one  will  recognize  the  attractiveness  and 
value  which  this  work  derives  from  thus  presenting 
the  opinions  of  these  two  masters  side  by  side.  But, 
it  must  be  admitted,  what  has  made  the  fortune  of 
the  book,  is  the  fact  that  it  contains  the  "  most  com- 
plete embodiment  of  the  veritable  doctrines  of  the 
Hopital  du  Midi,"  which  has  ever  been  msde  public. 
The  doctrinal  ideas  of  M.  Ricord,  ideas  which,  if  not 
universally  adopted,  are  incontestably  dominant,  have 
heretofore  only  been  interpreted  by  more  or  less  skilful 
secretaries,  sometimes  accredited  and  sometimes  not. 


In  the  notes  to  Hunter,  the  master  substitutes  him- 
self for  his  interpreters,  and  gives  his  original  thoughts 
to  the  world,  in  a  summary  form  it  is  true,  but  in  a 
lucid  and  perfectly  intelligible  manner.  In  conclu- 
sion we  can  say  that  this  is  incontestably  the  best 
treatise  on  syphilis  with  which  we  are  acquainted, 
and,  as  we  do  not  often  employ  the  phrase,  we  may- 
be excused  for  expressing  the  hope  that  it  may  find 
a  place  in  the  library  of  every  physician  — Virginia 
Med.  and  Surg.  Journal. 


BY  THE   SAME   AUTHOR. 

LETTERS  ON  SYPHILIS,  addressed  to  the  Chief  Editor  of  the  Union  Medicale. 
With  an  Introduction,  by  Amedee  Latour.  Translated  by  W.  P.  Laltimore,  M.  D.  In  one  neat 
octavo  volume. 

Blanchard  &  Lea  are  now  the  publishers  of  this  valuable  work. 

From  the  Translator's  Preface. 

To  those  who  have  listened  to  the  able  and  interesting  lectures  of  our  author  at  the  Hopital  du 
Midi,  this  volume  will  need  no  commendation;  while  to  those  who  have  not  had  the  pleasure  to 
which  we  allude,  the  book  will  commend  itself  by  the  truths  it  contains,  told  as  they  are  in  the 
same  inimitable  style  in  which  M.  Ricord  delivers  his  clinical  lectures. 

BY  THE   SAME  AUTHOR. 

A  PRACTICAL  TREATISE  ON  VENEREAL  DISEASES.  With  a  Thera- 
peutical Summary  and  Special  Formulary.  Translated  by  SIDNEY  DOANE,  M.  D.  Fourth  edition. 
One  volume,  octavo,  340  pages. 


BLANCHARD  &  LEA'S  MEDICAL 


RIGBY  (EDWARD),   M.  D., 

Physician  to  the  General  Lying-in  Hospital,  &c. 

A   SYSTEM   OF   MIDWIFERY.     With   Notes  and   Additional  Illustrations. 
Second  American  Edition.    One  volume  octavo,  422  pages. 


ROYLE  (J.  FORBES),  M.  D. 
MATERIA  MEDICA  AND  THERAPEUTICS;  including  the  Preparations  of 

the  Pharmacopoeias  of  London,  Edinburgh,  Dublin,  and  of  the  United  States.  With  many  new 
medicines.  Edited  by  JOSEPH  CARSON,  M.  D.,  Professor  of  Materia  Medica  and  Pharmacy  in 
the  University  of  Pennsylvania.  With  ninety-eight  illustrations,  in  one  large  octavo  volume. 
of  about  seven  hundred  pages. 

This  work  is,  indeed,  a  most  valuable  one,  and    ductions  on  the  other  extreme,  which  are  neces- 
will  fill  up  an  important  vacancy  that  existed  be-     sarily  imperfect  from  their  small  extent. — British 
tween  Dr.    Pereira's    most    learned  and   complete    and  Foreign  Medical  Review. 
system  of  Materia  Medica,  and   the  class  of  pro- 


SKEY  (FREDERICK  C.),   F.  R.  S.,  &c. 
OPERATIVE  SURGERY.     In  one  very  handsome  octavo  volume  of  over  650 

pages,  with  about  one  hundred  wood-cuts. 


Its  literary  execution  is  superior  to  most  surgical 
treatises.  It  abounds  in  excellent  moral  hints,  and 
is  replete  with  original  surgical  expedients  and  sug- 
gestions.— Buffalo  Med.  and  Surg.  Journal. 

With  high  talents,  extensive  practice,  and  a  long 
experience,  Mr.  Skey  is  perhaps  competent  to  the 
task  of  writing  a  complete  work  on  operative  sur- 


gery. 


-Charleston  Med.  Journal. 


We  cannot  withhold  from  this  work  our  high  com- 
mendation. Students  and  practitioners  will  find  it  an 
invaluable  teacher  and  guide  upon  every  topic  con- 
nected with  this  department.— N.  Y.  Medical  Ga- 
zette. 

A  work  of  the  very  highest  importance — a  w»rk 
by  itself. — London  Med.  Gazette. 


SHARPEY  (WILLIAM),    M.D.,   JONES   QUAIN,   M.  D.,  AND 
RICHARD  QUAIN,    F.  R.  S.,  &c. 

HUMAN  ANATOMY.     Revised,  with  Notes  and  Additions,  by  JOSEPH  LEIDY, 

M.  D.     Complete  in  two  large  octavo  volumes,  of  about  thirteen  hundred  pages.     Beautifully 
illustrated  with  over  five  hundred  engravings  on  wood. 

We  have  no  hesitation  in  recommending  this  trea- 


It  is  indeed  a  work  calculated  to  make  an  era  in 
anatomical  study,  by  placing  before  the  student 
every  department  of  his  science,  with  a  view  to 
the  relative  importance  of  each ;  and  so  skilfully 
have  the  different  parts  been  interwoven,  that  no 
one  who  makes  this  work  the  basis  of  his  studies, 
will  hereafter  have  any  excuse  for  neglecting  or 
undervaluing  any  important  particulars  connected 
with  the  structure  of  the  human  frame;  and 
whether  the  bias  of  his  mind  lead  him  in  a  more 
especial  manner  to  surgery,  physic,  or  physiology, 
he  will  find  here  a  work  at  once  so  comprehensive 
and  practical  as  to  defend  him  from  exclusiveness 
on  the  one  hand,  and  pedantry  on  the  other. — 
Monthly  Journal  and  Retrospect  of  the  Medical 
Sciences. 


tise  on  anatomy  as  the  most  complete  on  that  sub- 
ject in  the  English  language;  and  the  only  one, 
perhaps,  in  any  language,  which  brings  the.  state 
of  knowledge  forward  to  the  most  recent  disco- 
veries.— The  Edinburgh,  Med.  and  Surg.  Journal. 

Admirably  calculated  to  fulfil  the  object  for  whieh 
it  is  intended. — Provincial  Medical  Journal. 

The  most  complete  Treatise  on  Anatomy  in  the 
English  language. — Edinburgh,  Medical  Journal. 

There  is  no  work  in  the  English  language  to  be 
preferred  to  Dr.  Quain's  Elements  of  Anatomy. — 
London  Journal  of  Medicine. 


SMITH  (HENRY    H.),  M.D.,  AND   HORN  ER  (Wl  LLI  AM  E.),   M.D. 

AN  ANATOMICA.L  ATLAS,  illustrative  of  the  Structure  of  the  Human  Body. 
In  one  volume,  large  imperial  octavo,  with  about  six  hundred  and  fifty  beautiful  figures. 

late  the  student  upon  the  completion  of  this  Atlas, 
as  it  is  the  most  convenient  work  of  the  kind  that 
has  yet  appeared  ;  and  we  must  add,  the  very  beau- 
tiful manner  in  which  it  is  "  got  up"  is  so  creditable 
to  the  country  as  to  be  flattering  to  our  national 
pride. — American  Medical  Journal. 


These  figures  are  well  selected,  and  present  a 
complete  and  accurate  representation  of  that  won- 
derful fabric,  the  human  body.  The  plan  of  this 
Atlas,  which  renders  it  so  peculiarly  convenient 
for  the  student,  and  its  superb  artistical  execution, 
have  been  already  pointed  out.  We  must  congratu- 


SARGENT  (F.  W.),  M.  D. 
ON  BANDAGING  AND  OTHER  POINTS  OF  MINOR  SURGERY.    In 

one  handsome  royal  12mo.  volume  of  nearly  400  pages,  with  128  wood-cuts. 


The  very  best  manual  of  Minor  Surgery  we  have 
seen  ;  an  American  volume,  with  nearly  four  hundred 
pages  of  good  practical  lessons,  illustrated  by  about 
one  hundred  and  thirty  wood-cuts.  In  these  days 
of  "  trial,"  when  a  doctor's  reputation  hangs  upon 
a  clove  hitch,  or  the  roll  of  a  bandage,  it  would  be 
well,  perhaps,  to  carry  such  a  volume  as  Mr.  Sar- 
gent's always  in  our  coat-pocket,  or,  at  all  events, 
to  listen  attentively  to  his  instructions  at  home.— 
Buffalo  Med.  Journal. 


We  have  carefully  examined  this  work,  nful  find  it 
well  executed  and  admirably  adapted  to  the  use  of 
the  student.  Besides  the  subjects  usually  embraced 
in  works  on  Minor  Surgery,  there  is  a  short  chapter 
on  bathing,  another  on  anaesthetic  agents,  and  an 
appendix  of  formulae.  The  author  hasgiven  an  ex- 
cellentwork  on  this  subject, and  his  publishers  have 
illustrated  and  printed  it  in  most  beautiful  style. — 
|  The  Charleston  Medical  Journal. 


STANLEY  (EDWARD). 

A  TREATISE  ON  DISEASES  OF  THE  BONES. 

extra  cloth,  286  pages. 


In  one  volume,  octavo, 


AND    SCIENTIFIC    PUBLICATIONS.  27 

STILLE  (ALFRED),  M.  D. 
PRINCIPLES  OF  THERAPEUTICS.     In  one  handsome  volume.  (Preparing.) 


SIMON   (JOHN),  F.  R.  S. 

GENERAL  PATHOLOGY,  as  conducive  to  the  Establishment  of  Rational 
Principles  for  the  Prevention  and  Cure  of  Disease.  A  Course  of  Lectures  delivered  at  St. 
Thomas's  Hospital  during  the  summer  Session,  of  1850.  In  one  neat  octavo  volume. 


SMITH  (TYLER  W.),  M.  D., 

Lecturer  on  Obstetrics  in  the  Hunterian  School  of  Medicine. 

ON   PARTURITION,    AND    THE    PRINCIPLES    AND    PRACTICE    OF 

OBSTETRICS.    In  one  large  duodecimo  volume,  of  400  pages. 


SIBSON   (FRANCIS),    M.  D., 

Physician  to  St.  Mary's  Hospital. 

MEDICAL  ANATOMY.     Illustrating  the  Form,  Structure,  and  Position  of  the 

Internal  Organs  in  Health  and  Disease.  In  large  imperial  quarto,  with  splendid  colored  plates. 
To  match  "Maclise's  Surgical  Anatomy."  (Preparing.) 

SOLLY  (SAMUEL),    F.  R.  S. 

THE  HUMAN  BRAIN;  its  Structure,  Physiology,  and  Diseases.  With  a 
Description  of  the  Typical  Forms  of  the  Brain  in  the  Animal  Kingdom.  From  the  Second  and 
much  enlarged  London  edition.  In  one  octavo  volume,  with  120  wood-cuts. 

SCHOEDLER  (FRIEDRICH),  PH.D., 

Professor  of  the  Natural  Sciences  at  Worms,  &c. 

THE   BOOK   OF   NATURE;   an  Elementary  Introduction  to  the  Sciences  of 

Physics,  Astronomy,  Chemistry,  Mineralogy,  Geology,  Botany,  Zoology,  and  Physiology.  First 
American  edition,  with  a  Glossary  and  other  Additions  and  Improvements ;  from  the  second 
English  edition.  Translated  from  the  sixth  German  edition,  by  HENRY  MEDLOCK,  F.  C.  S.,  &c. 
In  one  thick  volume,  small  octavo,  of  about  seven  hundred  pages,  with  679  illustrations  on  wood. 
Suitable  for  the  higher  Schools  and  private  students.  (Now  Ready.) 

seen  presents  the  reader  with  so  wide  a  range  of  ele- 
mentary knowledge,  with  so  full  illustrations,  at  ao 
cheap  a  rate. — Silliman's  Journal,  Nov.  1853. 


This  volume,  as  its  title  shows,  covers  nearly  all 
the  sciences,  and  embodies  a  vast  amount  of  informa- 
tion for  instruction.  No  other  work  that  we  have 


TAYLOR  (ALFRED  S.),  M .  D.,  F.  R.  S., 

Lecturer  on  Medical  Jurisprudence  and  Chemistry  in  Guy's  Hospital. 

MEDICAL  JURISPRUDENCE.     Third  American,  from  the  fourth  and  improved 

English  Edition.    With  Notes  and  References  to  American  Decisions,  by  EDWARD  HARTSHORNE, 
M.  D.    In  one  large  octavo  volume,  of  about  seven  hundred  pages.     (Just  Issued.) 

reference,  that  would  be  more  likely  to  afford  the  aid 


acts,  the  whole  constituting  by  far  the  best. 
iable,  and  interesting  treatise  on  Medical 


We  know  of  no  work  on  Medical  Jurisprudence 
which  contains  in  the  same  space  anything  like  the 
same  amount  of  valuable  matter.  —  2V.  Y.  Journal  of 
Medicine. 

The  American  editor  has  appended  several  im- 
portant fa 
most  reliable 

Jurisprudence,  and  one  that  we  cannot  too  strongly 
recommend  to  all  who  desire  to  become  acquainted 
with  the  true  and  correct  exposition  of  this  depart- 
ment of  medical  literature.  —  Northern  Lancet. 

No  work  upon  the  subject  can  be  put  into  the 
hands  of  students  either  of  law  or  medicine  which 
will  engage  them  more  closely  or  profitably  ;  and 
none  could  be  offered  to  the  busy  practitioner  of 
either  calling,  for  the  purpose  of  casual  or  hasty 


desired.  We  therefore  recommend  it  as  the  best  and 
safest  manual  for  daily  use.— American  Journal  of 
Medical  Sciences. 

We  have  heretofore  had  reason  to  refer  to  it  in 
terms  of  commendation,  and  need  now  only  state 
that,  in  the  edition  before  us,  the  author  has  com- 
pletely revised  the  whole  work,  making  many  addi- 
tions and  alterations,  and  brought  it  fully  up  to  the 
present  state  of  knowledge.  The  task  of  the  Ameri- 
can editor  has  been  to  present  all  the  important 
facts  and  cases  that  have  recently  occurred  in  our 
own  country,  bearing  on  the  subjects  treated  of. 
No  better  work  can  be  placed  in  the  hands  of  the 
physician  or  jurist.— St.  Louis  Medical  and  Surgical 
Journal. 


BY   THE    SAME   AUTHOR. 

ON  POISONS,  IN  RELATION  TO  MEDICAL  JURISPRUDENCE   AND 

MEDICINE.    Edited,  with  Notes  and  Additions,  by  R.  E.  GRIFFITH,  M.  D.    In  one  large  octavo 
volume,  of  688  pages. 


The  most  elaborate  work  on  the  subject  that  our 
literature  possesses. — British  and  Foreign  Medico- 
Chirurgical  Review. 

It  contains  a  vast  body  of  facts,  which  embrace 
all  that  is  important  in  toxicology,  all  that  is 
necessary  to  the  guidance  of  the  medical  jurist,  and 
all  that  can  be  desired  by  the  lawyer.  —  Medico- 
Ckirurgical  Review. 


One  of  the  most  practical  and  trustworthy  works 
on  Poisons  in  our  language. — Western  Journal  q/ 
Medicine. 

It  is,  so  far  as  our  knowledge  extends,  incompa- 
rably the  best  upon  the  subject;  in  the  highest  de- 
gree creditable  to  the  author,  entirely  trustworthy. 
and  indispensable  to  the  student  and  practitioner.— 
N.  Y.  Annalist 


THOMSON  (A.  T.),  M.  D.,  F.  R.  S.,  &c. 
DOMESTIC  MANAGEMENT   OF  THE   SICK  ROOM,  necessary  in  aid  of 

Medical  {Treatment  for  the  Cure  of  Diseases.    Edited  by  R.  E.  GRIFFITH,  M.  D.     In  one  large 
royal  12mo.  volume,  with  wood-cuts,  360  pages. 


28  BLANCHARD    &   LEA'S    MEDICAL 

TOMES  (JOHN),    F.  R.  S. 
A  MANUAL  OF  DENTAL  PRACTICE.     Illustrated  by  numerous  engravings 

on  wood.    In  one  handsome  volume.     (Preparing.) 

TODD  (R.  B.),   M.  D.,  AND  BOWMAN  (WILLIAM),   F.  R.  S. 

PHYSIOLOGICAL    ANATOMY  AND    PHYSIOLOGY  OF  MAN.    With 

numerous  handsome  wood-cuts.    Parts  I,  II,  and  III,  in  one  octavo  volume,  552  pages.     Part  IV 

will  complete  the  work. 

The  distinguishing  peculiarity  of  this  work  is,  that  the  authors  investigate  for  themselves  every 
fact  asserted ;  and  it  is  the  immense  labor  consequent  upon  the  vast  number  of  observations  re- 
quisite to  carry  out  this  plan,  which  has  so  long  delayed  the  appearance  of  its  completion.  The 
first  portion  ot  Part  IV,  with  numerous  original  illustrations,  was  published  in  the  Medical  News 
and  Library  for  1853,  and  the  completion  will  be  issued  immediately  on  its  appearance  in  London. 
Those  who  have  subscribed  since  the  appearance  of  the  preceding  portion  of  the  work  can  have 
the  three  parts  by  mail,  on  remittance  of  $2  50  to  the  publishers. 

TRANSACTIONS  OF   THE   AMERICAN    MEDICAL  ASSOCIATION. 
VOLUME  VI,  for  1853,  large  8vo.;  of  870  pages,  with  numerous  colored  plates 

and  wood-cuts. 
Also  to  be  had,  a  few  sets  of  the  Transactions  from  1848  to  1853,  in  six  large  octavo  volumes. 

price  $25.     These  volumes  are  all  published  by  and  sold  on  account  of  the  Association. 

WATSON   (THOMAS),    M.D.,    &c. 
LECTURES    ON    THE   PRINCIPLES    AND    PRACTICE   OF   PHYSIC. 

Third  American,  from  the  last  London  edition.    Revised,  with  Additions,  by  D.  FRANCIS  CONDIE, 

M.  D.,  author  of  a  "  Treatise  on  the  Diseases  of  Children,"  &c.     In  one  octavo  volume,  of  nearly 

eleven  hundred  large  pages,  strongly  bound  with  raised  bands. 

To  say  that  it  is  the  very  best  work  on  the  sub- 
ject now  extant,  is  but  to  echo  the  sentiment  of  the 
medical  press  throughout  the  country.  —  N.  O. 
Medical  Journal . 

Of  the  text-books  recently  republished  Watson  is 
rery  justly  the  principal  favorite. — Holmes's  Rep. 
to  Nat.  Med.  Assoc. 

By  universal  consent  the  work  ranks  among  the 
very  best  text-books  in  our  language. — Illinois  and 
Indiana  Med.  Journal. 

Regarded  on  all  hands  as  one  of  the  very  best,  if 
not  the  very  best,  systematic  treatise  on  practical 
medicine  extant. — St.  Louis  Med.  Journal. 


Confessedly  one  of  the  very  best  works  on  the 
principles  and  practice  of  physic  in  the  English  or 
any  other  language. — Med.  Examiner. 

Asa  text- book  it  has  no  equal ;  as  a  compendium 
of  pathology  and  practice  no  superior. — New  York 
Annalist. 

We  know  of  no  work  better  calculated  for  being 
placed  in  the  hands  of  the  student,  and  for  a  text- 
book; on  every  important  point  the  author  seems 
to  have  posted  up  hia  knowledge  to  the  day.-- 
Amer.  Med.  Journal. 

One  of  the  most  practically  useful  books  that 
ever  was  presented  to  the  student.  —  N.  Y.  Med. 
Journal. 


WALSHE   (W.    H.),    M.  D., 

Professor  of  the  Principles  and  Practice  of  Medicine  in  University  College,  London. 

DISEASES    OF    THE    HEART,    LUNGS,    AND    APPENDAGES;    their 

Symptoms  and  Treatment.     In  one  handsome  volume,  large  royal  12mo.,  512  pages. 
We  consider  this  as  the  ablest  work  in  the  En-  1  the  author  being  the  first  stethoscopist  of  the  day.— 
rlish  language,  on  the  subject  of  which  it  treats;  |  Charleston  Medical  Journal. 

WHAT   TO   OBSERVE 
AT    THE    BEDSIDE    AND    AFTER   DEATH,    IN    MEDICAL    CASES. 

Published  under  the  authority  of  the  London  Society  for  Medical  Observation.     In  one  very- 
handsome  volume,  royal  12mo  ,  extra  cloth.     (Just  Issued.) 
We  hail  the  appearance  of  this  book  as  the  grand  j  given  to  the  world,   through  a  small    but  useful 


desideratum.— Charleston  Medical  Journal. 

This  is  truly  a  very  capital  book.  The  whole 
medical  world  will  reap  advantages  from  its  publi- 
cation. The  medical  journals  will  soon  show  its 
influence  on  the  character  of  the  '  <  Reports  of  Cases" 
which  they  publish.  Drs.  Ballard  and  Walshe  have 


medical  organization,  a  cheap  but  invaluable  book. 
We  do  advise  every  reader  of  this  notice  to  buy  it 
and  use  it.  Unless  he  is  so  vain  as  to  imagine  him- 
self superior  to  the  ordinary  human  capacity,  lie  will 
in  six  months  see  its  inestimable  advantages. — 
Stethoscope. 


WILDE   (W.    R.), 

Surgeon  to  St.  Mark's  Ophthalmic  and  Aural  Hospital,  Dublin. 

AURAL  SURGERY,  AND  THE  NATURE  AND  TREATMENT  OF  DIS- 
EASES OF  THE  EAR.    In  one  handsome  octavo  volume,  with  illustrations.     (Now  Ready.) 
So  little  is  generally  known  in  this  country  concerning  tne  causes,  symptoms,  and  treatment  ol 
aural  affections,  that  a  practical  and  scientific  work  on  that  subject,  from  a  practitioner  of  Mr. 
Wilde's  great  experience,  cannot  fail  to  be  productive  of  much  benefit,  by  attracting  attention 
to  this  obscure  class  of  diseases,  which  too  frequently  escape  attention  until  past  relief.     The  im- 
mense number  of  cases  which  have  come  under  Mr.  Wilde's  observation  for  many  years,  have 
afforded  him  opportunities  rarely  enjoyed  for  investigating  this  branch  of  medical  science,  and  inn 
work  may  therefore  be  regarded  as  of  the  highest  authority. 


This  work  certainly  contains  more  information  on 
the  subject  to  which  it  is  devoted  than  any  other 
with  which  we  are  acquainted.  We  feel  grateful  to 
the  author  for  his  manful  effort  to  rescue  this  depart- 
ment of  surgery  from  the  hands  of  the  empirics  who 
nearly  monopolize  it.  We  think  he  has  successfully 
shown  that  aural  diseases  are  not  beyond  the  re- 
sources of  art ;  that  they  are  governed  by  the  same 


laws,  and  amenable  to  the  same  general  method?  of 
treatment  as  other  morbid  processes.  The  work  i* 
not  written  to  supply  the  cravings  of  popular  patro- 
nage, but  it  is  wholly  addressed  to  the  profession, 
and  bears  on  every  page  the  impress  of  the  reflection* 
of  a  sagacious  and  practical  surgeon. —  Va.  Surg.  and 
Med.  Journal. 


AND    SCIENTIFIC    PUBLICATIONS. 


29 


WILSON    (ERASMUS),   M.D.,    F.  R.  S., 

Lecturer  on  Anatomy,  London. 

A  SYSTEM  OF  HUMAN  ANATOMY,  General  and  Special.     Fourth  Ameri- 
can, from  the  last  English  edition.     Edited  by  PAUL  B.  GODDARD,  A.  M.,-M.  D.    With  two  hun- 
dred and  fifty  illustrations.     Beautifully  printed,  in  one  large  octavo  volume,  oi  nearly  six  hun- 
dred pages. 
In  many,  if  not  all  the  Colleges  of  the  Union,  it  i      It  offers  to  the  student  all  the  assistance  that  can 


has  become  a  standard  text-book.  This,  of  itself, 
is  sufficiently  expressive  of  its  value.  A  work  very 
desirable  to  the  student;  one,  the  possession  of 
which  will  greatly  facilitate  his  progress  in  the 
study  of  Practical  Anatomy. — New  York  Journal  of 
Medicine. 


be  expected  from  such  a  work. — Medical  Examiner. 

The  most  complete  and  convenient  manual  for  the 
student  we  possess. — American  Journal  of  Meditat 
Science. 

In  every  respect,  this  work  as  an  anatomical 
guide  for  the  student  and  practitioner,  merits  our 


Its  author  ranks  with  the  highest  on  Anatomy. —  !  warmest  and  most  decided  praise. — London  Medieal 
Southern  Medical  and  Surgical  Journal.  I  Gazette. 

BY   THE   SAME   AUTHOR. 

THE  DISSECTOR;  or,  Practical  and  Surgical  Anatomy.  Modified  and  Re- 
arranged, by  PAUL,  BECK  GODDARD,  M.  D.  A  new  edition,  with  Revisions  and  Additions.  In 
one  large  and  handsome  volume,  royal  12mo.,  with  one  hundred  and  fifteen  illustrations. 

In  passing  this  work  again  through  the  press,  the  editor  has  made  such  additions  and  improve- 
ments as  the  advance  of  anatomical  knowledge  has  rendered  necessary  to  maintain  the  work  in  the 
high  reputation  which  it  has  acquired  in  the  schools  of  the  United  States,  as  a  complete  and  faithful 
guide  to  the  student  of  practical  anatomy.  A  number  of  new  illustrations  have  been  added,  espe- 
cially in  the  portion  relating  to  the  complicated  anatomy  of  Hernia.  In  mechanical  execution  the 
work  will  be  found  superior  to  former  editions. 

BY   THE   SAME   AUTHOR. 

ON  DISEASES  OF  THE  SKIN.  Third  American,  from  the  third  London 
edition.  In  one  neat  octavo  volume,  of  about  five  hundred  pages,  extra  cloth.  (Just  Issued.) 
Also,  to  be  had  done  up  with  fifteen  beautiful  steel  plates,  of  which  eight  are  exquisitely  colored  ; 
representing  the  Normal  and  Pathological  Anatomy  of  the  Skin,  together  with  accurately  colored 
delineations  of  more  than  sixty  varieties  of  disease,  most  of  them  the  size  of  nature.  The  Plates 
are  also  for  sale  separate,  done  up  in  boards. 

The  increased  size  of  this  edition  is  sufficient  evidence  that  the  author  has  not  been  content 
with  a  mere  republication,  but  has  endeavored  to  maintain  the  high  character  of  his  work  as  the 
standard  text-book  on  this  interesting  and  difficult  class  of  diseases.  He  has  thus  introduced  such 
new  matter  as  the  experience  of  the  last  three  or  four  years  has  suggested,  and  has  made  such 
alterations  as  the  progress  of  scientific  investigation  has  rendered  expedient.  The  illustrations  have 
also  been  materially  augmented,  the  number  of  plates  being  increased  from  eight  to  sixteen. 


Of  these  plates  it  is  impossible  to  speak  too  highly. 
The  representations  of  the  various  forms  of  cuta- 
neous disease  are  singularly"  accurate,  and  the  color- 
ing exceeds  almost  anything  we  have  met  with  in 
point  of  delicacy  and  finish. — British  and  Foreign 
Medical  Review. 


The  "Diseases  of  the  Skin,"  by  Mr.  Erasmus 
Wilson,  may  now  be  regarded  as  the  standard  work 
in  that  department  of  medical  literature.  The 
plates  by  which  this  edition  is  accompanied  leave 
nothing  to  be  desired,  so  far  as  excellence  of  delinea- 
tion and  perfect  accuracy  of  illustration  are  con- 
cerned.— Medico- Chirurgical  Review. 

BY   THE   SAME   AUTHOR. 

ON    CONSTITUTIONAL    AND    HEREDITARY    SYPHILIS,   AND    ON 

SYPHILITIC  ERUPTIONS.     In  one  small  octavo  volume,  beautifully  printed,  with  four  exqui- 
site colored  plates,  presenting  more  than  thirty  varieties  of  syphilitic  eruptions. 

and 

we  are  satis- 
fied, be  received  as  decisive,  in  regard  to  many 
questiones  vexatae.  They  appear  to  us  entitled  to 
notice  at  some  length. — Medical  Examiner. 


connection  with  its  transmissibility,  pathology 
sequelae.  His  facts  and  references  will,  weare  s 


Dr.  Wilson's  views  on  the  general  subject  of 
Syphilis  appear  to  us  in  the  main  sound  and  judi- 
cious, and  we  commend  the  book  as  an  excellent 
monograph  on  the  subject.  Dr.  Wilson  has  pre- 
sented us  a  very  faithful  and  lucid  description  of 
Syphilis  and  has  cleared  up  many  obscure  points  in 

BY  THE  SAME  AUTHOR.     (Now  Ready.) 

HEALTHY  SKIN;  A  Popular  Treatise  on  the  Skin  and  Hair,  their  Preserva- 
tion and  Management.  Second  American,  from  the  fourth  London  edition.  One  neat  volume, 
royal  12mo.,  with  numerous  illustrations. 

Copies  can  be  had  done  up  in  paper  covers  for  mailing,  price  75  cents. 


WHITEHEAD  (JAMES),    F.  R.  C.  S.5    &c. 
THE  CAUSES  AND  TREATMENT  OF  ABORTION  AND   STERILITY; 

being  the  Result  of  an  Extended  Practical  Inquiry  into  the  Physiological  and  Morbid  Conditions 
of  the  Uterus.     Second  American  Edition.     In  one  volume,  octavo,  368  pages.     (Now  Ready.) 

this  department  of  our  profession,  that  the  practi- 
tioner who  does  not  consult  the  recent  works  on  the 
complaints  of  females,  will  soon  find  himself  in  the 
rear  of  his  more  studious  brethren.  This  is  one  of 
the  works  which  must  be  studied  by  those  who 
would  know  what  the  present  state  of  our  knowledge 
is  respecting  the  causes  and  treatment  of  abortion 
and  sterility. — The  Western  Journal  of  Medicine  and 
Surgery. 


The  simple  title  of  this  work  gives  a  very  imper- 
fect idea  of  its  contents.  The  subject  of  sterility 
occupies  a  mere  fraction  of  space,  and  upwards  of 
one-half  of  the  whole  volume  is  taken  up  with  an 
elaborate  account  of  menstruation  as  a  physiological 
process,  and  of  the  disorders  which  its  deviations 
from  health  are  apt  to  produce. — Medical  Ckirurg. 
Revieio . 

Such  are  the  advances  made  from  year  to  year  in 


30 


BLANCHARD    &   LEA'S   MEDICAL 


WEST   (CHARLES),    M.  D., 

Physician  to  the  Hospital  for  Sick  Children,  &c. 

LECTURES   ON   THE   DISEASES   OF  INFANCY  AND  CHILDHOOD. 

Second  American,  from  the  Second  and  Enlarged  London  edition.     In  one  volume,  octavo,  of 
nearly  five  hundred  pages.    (Now  Ready.) 

From  the  Preface  to  the  Second  Edition. 

In  the  preparation  of  the  second  edition  of  these  Lectures,  the  whole  work  has  been  carefully 
revised.  A  few  formulae  have  been  introduced  and  a  minute  alphabetical  index  has  been  appended 
while  additions  amounting  altogether  to  fifty  pages,  have  been  made,  wherever  I  felt  that  more 
extended  observation,  or  more  careful  reflection  had  enabled  me  to  supply  some  of  those  deficiencies 
which  I  am  well  aware,  'are  still  far  too  numerous.  The  work  now  contains  the  result  of  640 


observations,  and  199  post-mortem  examinations,  chiefly  made  among  16,276  children  who  came 
)tice  during  the  ten  years  of  my  connection  with  the  Children's  Infirmary  in  L.am  belli. 


under  my  not 


We  take  leave  of  Dr.  West  with  great  respect  for 
his  attainments,  a  due  appreciation  of  his  acute 
powers  of  observation,  and  a  deep  sense  of  obliga- 
tion for  this  valuable  contribution  to  our  profes- 
sional literature.  His  book  is  undoubtedly  in  many 
respects  the  best  we  possess  on  diseases  of  children. 
The  extracts  we  have  given  will,  we  hope,  satisfy 
our  readers  of  its  value ;  and  yet  in  all  candor  we 
must  say  thpt  they  are  even  inferior  to  some  other 
parts,  the  length  of  which  prohibited  our  entering 
upon  them.  That  the  book  will  shortly  be  in  the 
hands  of  most  of  our  readers  we  do  not  doubt,  and  it 
will  give  us  much  pleasure  if  our  strong  recommend- 
ation of  it  may  contribute  towards  the  result. — The 
Dublin  Quarterly  Journal  of  Medical  Science. 

Dr.  West  has  placed  the  profession  under  deep  ob- 
ligation by  this  able,  thorough,  and  finished  work 


upon  a  subject  which  almost  daily  taxes  to  the  ut- 
most the  skill  of  the  general  practitioner.  He  has 
with  singular  felicity  threaded  his  way  through  all 
the  tortuous  labyrinths  of  the  difficult  subject  he  has 
undertaken  to  elucidate,  and  has  in  many  of  the 
darkest  corners  left  a  light,  for  the  benefit  of  suc- 
ceeding travellers,  which  will  never  be  extinguished . 
Not  the  least  captivating  feature  in  this  admirable 
performance  is  its  easy,  conversational  style,  which 
acquires  force  from  its  very  simplicity,  and  leaves 
an  impression  upon  the  memory,  of  the  truths  it 
conveys,  as  clear  and  refreshing  as  its  own  purity. 
The  author's  position  secured  him  extraordinary  fa- 
cilities for  the  investigation  of  children's  diseases, 
and  his  powers  of  observation  and  discrimination 
have  enabled  him  to  make  the  most  of  these  great 
advantages. — Nashville  Medical  Journal. 


BY  THE  SAME  AUTHOR.     (Now  Ready.) 

AN  ENQUIRY  INTO  THE  PATHOLOGICAL  IMPORTANCE  OF  ULCER- 

ATION  OF  THE  OS  UTERI.    Being  the  Croonian  Lectures  for  the  year  1854.    In  one  neat 
octavo  volume,  extra  cloth. 

This  work  will  appear  in  the  "  Medical  News  and  Library"  during  the  latter  portion  of  1854,  and 
will  be  published  in  a  separate  form  about  December. 


WILLIAMS  (C.  J.  B.),    M.  D.,    F.  R.  S., 

Professor  of  Clinical  Medicine  in  University  College,  London,  &o. 

PRINCIPLES  OF  MEDICINE;  comprising  General  Pathology  and  Therapeu- 
tics,  and  a  brief  general  view  of  Etiology,  Nosology,  Semeiology,  Diagnosis,  Prognosis,  and 
Hygienics.  Edited,  with  Additions,  by  MEREDITH  CLYMER,  M.  D.  Fourth  American,  from  the 
last  and  enlarged  London  edition.  In  one  octavo  volume,  of  476  pages.  (Now  Ready.) 

This  new  edition  has  been  materially  enlarged  and  brought  up  by  the  editor. 

It  possesses  the  strongest  claims  to  the  attention  of  the  medical  student  and  practitioner,  from 
the  admirable  manner  in  which  the  various  inquiries  in  the  different  branches  of  pathology  are 
investigated,  combined,  and  generalized  by  an  experienced  practical  physician,  and  directly  applied 
to  the  investigation  and  treatment  of  disease. — EDITOR'S  PREFACE. 

The  best  exposition  in  our  language,  or,  we  be-  Few  books  have  proved  more  useful,  or  met  with 

lieve,  in  any  language,  of  rational  medicine,  in  its  a  more  ready  sale  than   this,  and  no  practitioner 

present  improved  and  rapidly  improving  state. —  should  regard  his  library  as  complete  without  it. 

British  and  Foreign  Medico-Chirurg.  Review.  — Ohio  Med.  and  Surg.  Journal. 


BY   THE   SAME   AUTHOR. 

A  PRACTICAL  TREATISE  ON  DISEASES  OF  THE  RESPIRATORY 

ORGANS ;  including  Diseases  of  the  Larynx,  Trachea,  Lungs,  and  Pleurae.    With  numerous 
Additions  and  Notes,  by  M.  CLYMER,  M.  D.    With  wood-cuts.    In  one  octavo  volume,  pp.  50S. 


YOUATT   (WILLIAM),  V.  S. 

THE  HORSE.  A  new  edition,  with  numerous  illustrations;  together  with  a 
general  history  of  the  Horse;  a  Dissertation  on  the  American  Trotting  Horse;  how  Trained  and 
Jockeyed ;  an  Account  of  his  Remarkable  Performances ;  and  an  Essay  on  the  Ass  and  the  Mule. 
By  J."  S.  SKINNER,  formerly  Assistant  Postmaster-General,  and  Editor  of  the  Turf  Register. 
One  large  octavo  volume. 

BY   THE   SAME   AUTHOR. 

THE   DOa.     Edited  by  E.  J.  LEWIS,   M.  D.     With   numerous  and  beautiful 

illustrations.     In  one  very  handsome  volume,  crown  Svo.,  crimson  cloth,  gilt. 


\ 


AND   SCIENTIFIC    PUBLICATIONS. 


31 


B.  &  L.  subjoin  a  condensed  list  of  their  publications  in  general  and  educational 
literature,  of  which  more  detailed  catalogues  will  be  furnished  on  application. 
HISTORY  AND   BIOGRAPHY. 


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